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Sample records for aspheric intraocular lenses

  1. Combining zonal refractive and diffractive aspheric multifocal intraocular lenses.

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    Muñoz, Gonzalo; Albarrán-Diego, César; Javaloy, Jaime; Sakla, Hani F; Cerviño, Alejandro

    2012-03-01

    To assess visual performance with the combination of a zonal refractive aspheric multifocal intraocular lens (MIOL) (Lentis Mplus, Oculentis GmbH) and a diffractive aspheric MIOL (Acri.Lisa 366, Acri.Tech GmbH). This prospective interventional cohort study comprised 80 eyes from 40 cataract patients (mean age: 65.5±7.3 years) who underwent implantation of the Lentis Mplus MIOL in one eye and Acri.Lisa 366 MIOL in the fellow eye. The main outcome measures were refraction; monocular and binocular uncorrected and corrected distance, intermediate, and near visual acuities; monocular and binocular defocus curves; binocular photopic contrast sensitivity function compared to a monofocal intraocular lens (IOL) control group (40 age-matched pseudophakic patients implanted with the AR-40e [Abbott Medical Optics]); and quality of vision questionnaire. Binocular uncorrected visual acuities were 0.12 logMAR (0.76 decimal) or better at all distances measured between 6 m and 33 cm. The Lentis Mplus provided statistically significant better vision than the Acri.Lisa at distances between 2 m and 40 cm, and the Acri.Lisa provided statistically significant better vision than the Lentis Mplus at 33 cm. Binocular defocus curve showed little drop-off at intermediate distances. Photopic contrast sensitivity function for distance and near were similar to the monofocal IOL control group except for higher frequencies. Moderate glare (15%), night vision problems (12.5%), and halos (10%) were reported. Complete independence of spectacles was achieved by 92.5% of patients. The combination of zonal refractive aspheric and diffractive aspheric MIOLs resulted in excellent uncorrected binocular distance, intermediate, and near vision, with low incidence of significant photic phenomena and high patient satisfaction. Copyright 2012, SLACK Incorporated.

  2. [Depth of focus in spherical and aspheric intraocular lenses].

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    Nan, Li; Tang, Xin; Liu, Yong-ji

    2012-02-01

    To investigate depth of focus (DOF) in spherical and aspheric IOL eye models. Computer numerical simulation experiment was used. IOL eye model based on Liou-Brennan eye model was constructed by using ZEMAX optical design software. Different IOL were implanted in this eye model. Monochromatic through focus modulation transfer function (MTF) curves were computed. Pupil and aspheric designs' effect on DOF were analyzed. DOF of eye model increased with pupil shrinkage in 550 nm monochromatic light (FY60AD 1.20 D at 6 mm pupil, 1.35 D at 5 mm pupil, 1.70 D at 4 mm pupil, 2.46 D at 3 mm pupil; YA60BBR 1.24 D at 6 mm pupil, 1.48 D at 5 mm pupil, 1.80 D at 4 mm pupil, 2.50 D at 3 mm pupil). MTF in spherical IOL eye model was higher with minus defocus, this trend was obvious at larger pupil. MTF of aspheric IOL eyes were higher than spherical IOL eyes when well focused at 5 mm pupil, while the DOF was lower in aspheric IOL with negative spherical aberration (Tecnis Z9000 1.31 D, FY60AD 1.35 D, CeeOn911 1.55 D, YA60BBR 1.48 D). DOF decreased less in aspheric IOL with zero spherical aberration (LI61AO 1.42 D). DOF in IOL eye model was higher at smaller pupil. When the pupil was large, well focused aspheric IOL improved optical quality compared with spherical IOL, while DOF and the tolerance to defocus in aspheric IOL were partially lost; this phenomenon was obvious with minus defocus.

  3. Evaluation of visual quality of spherical and aspherical intraocular lenses by Optical Quality Analysis System

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    Yan Chen

    2017-06-01

    Full Text Available AIM: To evaluate the impact of spherical and aspherical intraocular lenses on the postoperative visual quality of age-related cataract patients using Optical Quality Analysis System (OQAS. METHODS: Seventy-four eyes with age-related cataracts were randomly divided into spherical and aspherical lens implantation groups. Best-corrected visual acuity (BCVA was measured preoperatively, one day, one week, two weeks, one month and two months after surgery. A biometric systems analysis using the OQAS objective scattering index (OSI was performed. RESULTS: There were no significant differences in visual acuity (P>0.05 before and after spherical and aspheric lens implantation. There was a negative linear correction between the OSI value and BCVA (r=-0.634, P=0.000, and positive corrections between the OSI value and the lens LOCUS III value of nucleus color (NC, nucleus opacity (NO, cortex (C and posterior lens capsular (P (r=0.704, P=0.000; r=0.514, P=0.000; r=0.276, P=0.020; r=0.417, P=0.000, respectively. OSI values of spherical vs aspherical lenses were 11.5±3.6 vs 11.8±3.4, 4.1±0.9 vs 3.3±0.8, 3.5±0.9 vs 2.7±0.7, 3.3±0.8 vs 2.6±0.7, 3.2±0.7 vs 2.5±0.8, and 3.2±0.8 vs 2.5±0.8 before and 1d, 1, 2wk, 1 and 2mo after surgery, respectively. All time points varied significantly (P<0.01 between the two groups. CONCLUSION: Aspherical IOLs does not significantly affect visual acuity compared with spherical IOLs. The OSI value, was significantly lower in the aspherical lens group compared with the spherical lens. This study shows that objective visual quality of aspheric IOLs is better than that of the spherical lens by means of OQAS biological measurement method.

  4. Effect of Spherical Aberration on the Optical Quality after Implantation of Two Different Aspherical Intraocular Lenses

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    Michael Lasta

    2017-01-01

    Full Text Available Purpose. To compare the effect of spherical aberration on optical quality in eyes with two different aspherical intraocular lenses. Methods. 120 eyes of 60 patients underwent phacoemulsification. In patients’ eyes, an aberration-free IOL (Aspira-aA; Human Optics or an aberration-correcting aspherical IOL (Tecnis ZCB00; Abott Medical Optics was randomly implanted. After surgery, contrast sensitivity and wavefront measurements as well as tilt and decentration measurements were performed. Results. Contrast sensitivity was significantly higher in eyes with Aspira lens under mesopic conditions with 12 cycles per degree (CPD and under photopic conditions with 18 CPD (p=0.02. Wavefront measurements showed a higher total spherical aberration with a minimal pupil size of 4 mm in the Aspira group (0.05 ± 0.03 than in the Tecnis group (0.03 ± 0.02 (p=0.001. Strehl ratio was higher in eyes with Tecnis (0.28 ± 0.17 with a minimal pupil size larger than 5 mm than that with Aspira (0.16 ± 0.14 (p=0.04. In pupils with a minimum diameter of 4 mm spherical aberration had a significant effect on Strehl ratio, but not in pupils with a diameter less than 4 mm. Conclusions. Optical quality was better in eyes with the aberration-correcting Tecnis IOL when pupils were large. In contrast, this could not be shown in eyes with pupils under 4 mm or larger. This trial is registered with Clinicaltrials.gov NCT03224728.

  5. Change in corneal aberrations after cataract surgery with 2 types of aspherical intraocular lenses.

    Science.gov (United States)

    Marcos, Susana; Rosales, Patricia; Llorente, Lourdes; Jiménez-Alfaro, Ignacio

    2007-02-01

    To study the effect of cataract surgery through 3.2 mm superior incisions on corneal aberrations with 2 types of monofocal intraocular lenses (IOLs) with an aspherical design. Instituto de Optica, Consejo Superior de Investigaciones Científicas, and Fundación Jiménez Díaz, Madrid, Spain. Corneal topography of 43 eyes was obtained before and after small corneal incision cataract surgery. Twenty-two eyes had implantation of a Tecnis Z9000 silicone IOL (Advanced Medical Optics) and 21 had implantation of an AcrySof IQ SN60WF acrylic IOL (Alcon Research Labs) using the recommended injector for each IOL type. The intended incision size (3.2 mm) was similar in the 2 groups. Corneal aberrations were estimated using custom-developed algorithms (based on ray tracing) for 10.0 mm and 5.0 mm pupils. Comparisons between preoperative and postoperative measurements and across the groups were made for individual Zernike terms and root-mean-square (RMS) wavefront error. The RMS (excluding tilt and defocus) did not change in the AcrySof IQ group and increased significantly in the Tecnis group with the 10.0 mm and 5.0 mm pupil diameters. Spherical aberration and coma-like terms did not change significantly; however, vertical astigmatism, vertical trefoil, and vertical tetrafoil changed significantly with surgery with the 10.0 mm and 5.0 mm pupil diameters (Porder aberrations consistently showed a superior lobe, resulting from a combination of positive vertical trefoil (Z(3)(-3)) and negative tetrafoil (Z(4)(4)). The mean vertical astigmatism increased by 2.47 microm +/- 1.49 (SD) and 1.74 +/- 1.44 microm, vertical trefoil increased by 1.81 +/- 1.19 microm and 1.20 +/- 1.34 microm, and tetrafoil increased by -1.10 +/- 0.78 microm and -0.89 +/- 0.68 microm in the Tecnis group and AcrySof IQ group, respectively. There were no significant differences between the corneal aberrations in the 2 postoperative groups, although there was a tendency toward more terms or orders changing

  6. Visual outcome and optical quality after bilateral implantation of aspheric diffractive multifocal, aspheric monofocal and spherical monofocal intraocular lenses: a prospective comparison

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    Ke Yao

    2013-06-01

    Full Text Available AIM: To evaluate the visual function after bilateral implantation of aspheric diffractive multifocal Tecnis ZMA00, aspheric monofocal ZA9003 versus spherical monofocal Akreos Adapt intraocular lenses (IOLs.METHODS: Tecnis ZMA00, Tecnis ZA9003 or Akreos Adapt IOLs were bilaterally implanted in 180 eyes from 90 patients. The following parameters were assessed 3 months postoperatively: monocular and binocular uncorrected visual acuity (UCVA and distance-corrected visual acuity (DCVA for distance, intermediate and near, spherical aberration (SA, contrast and glare sensitivity, near point refractive power, uncorrected and best-corrected near stereoscopic acuity (NSA. Patient satisfaction was assessed by a questionnaire.RESULTS: Three months postoperatively, the monocular and binocular UCVA and DCVA at near of Tecnis ZMA00 were significantly better than other two groups. The mean SA for 5.0mm optical zone in Tecnis ZMA00 and Tecnis ZA9003 was significantly lower than that in Akreos Adapt. Mean contrast sensitivity and glare sensitivity were better for Tecnis ZA9003 group than for other two groups. Patients with Tecnis ZMA00 had higher monocular and binocular near point refractive power and uncorrected NSA than monofocal groups. The patients in Tecnis ZMA00 had higher mean values for halo compared with other two groups.CONCLUSION: Tecnis ZMA00 provided better near VA and uncorrected NSA and higher near point refractive power than monofocal IOLs and patients were spectacle independent. The IOLs with Tecnis aspheric design improved contrast and glare sensitivity. Patients with Tecnis ZMA00 reported more disturbances on visual phenomena of halo.

  7. Mesopic visual quality after three kinds of aspheric acrylic monofocal intraocular lenses

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    Hai-Lun Ji

    2013-08-01

    Full Text Available AIM:To evaluate best corrected visual acuity(BCVAand contrast sensitivity(CSunder mesopic condition with no glare in patients following implantation of three different kinds of aspheric acrylic monofocal intraocular lens(IOLs.METHODS: Seventy-seven cases(90 eyesof age-related cataract patients were selected, who were undergone phacoemulsification and intraocular lens(IOLimplantation in our hospital during December 2011 to November 2012. Preoperatively, the patients were randomly divided into three groups: 30 eyes(25 caseswere implanted with hydrophobic yellow-tinted acrylic(HOYAIOLs in group 1; 30 eyes(28 caseswith hydrophilic acrylic IOLs(Raynerin group 2; 30 eyes(24 caseswith hydrophilic acrylic surface heparin processing IOLs(XOin group 3. All eyes were evaluated at 1 month and 3 months postoperatively. The BCVA and CS under mesopic condition without glare were measured and underwent statistical analysis.RESULTS: There was neither statistically significant difference in the BCVA(P>0.05, nor statistically significant difference in CS results(after standardization of contrast sensitivity value: lgCS(P>0.05between groups under mesopic condition, but the lgCS of the HOYA group decreased slightly. CONCLUSION: There were not marked differences of BCVA and CS between groups of patients at the follow-up intervals of 1 month and 3 months under mesopic condition. The blue-filter type artificial lens may protect the retina, thus, it is advisable to implant yellow-tinted filter blue artificial lens, especially for patients who are children or young persons.

  8. Evaluation of optical performance of 4 aspheric toric intraocular lenses using an optical bench system: Influence of pupil size, decentration, and rotation.

    Science.gov (United States)

    Kim, Min-Ji; Yoo, Young-Sik; Joo, Choun-Ki; Yoon, Geunyoung

    2015-10-01

    To evaluate the effect of pupil size, degree of intraocular lens (IOL) decentration, and rotation of 4 aspheric toric IOLs on the image quality. Department of Ophthalmology, Seoul St. Mary's Hospital, Seoul, South Korea. Experimental study. Four aspheric toric intraocular lenses (IOLs)-the Precizon (transitional conic toric IOL), AT Torbi 709M (bitoric IOL), SN6AT4 (posterior toric surface IOL), and ZCT225 (anterior toric surface IOL)-were evaluated using the optical bench metrology system. Measurements included changes in spherical aberrations, relative spherical equivalent (SE), and image quality at different pupil diameters and image quality degradation due to decentration and rotation of the IOLs. Change in relative SE with pupil size in aberration-free toric IOLs (transitional conic toric and bitoric IOLs) was greater than in negatively aspheric toric IOLs (posterior toric surface and anterior toric surface IOLs). In contrast, the aberration-free IOLs showed higher contrast than the negatively aspheric IOLs. When IOLs were decentered by 1.0 mm, the contrast reduction rates at 17.6 cycles per degree for the transitional conic toric IOL, bitoric IOL, posterior toric surface IOL, and anterior toric surface IOL were 5.1%, 3.1%, 12.2%, and 15.8%, respectively. Rotation-induced deterioration of contrast to 0.5 required a much higher rotation for the transitional conic toric IOL than for the other 3 IOLs. The transitional conic toric IOL and bitoric IOL provided superior image quality despite pupil size changes and the presence of decentration. The transitional conic toric IOL demonstrated maximum rotation tolerance compared with the other IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  9. Aspheric lenses for terahertz imaging.

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    Lo, Yat Hei; Leonhardt, Rainer

    2008-09-29

    We present novel designs for aspheric lenses used in terahertz (THz) imaging. As different surfaces result in different beam shaping properties and in different losses from reflection and absorption, the resultant imaging resolution (i.e. the focal spot size) depends critically on the design approach. We evaluate the different lens designs using Kirchhoff's scalar diffraction theory, and test the predictions experimentally. We also show that our lenses can achieve sub-wavelength resolution. While our lens designs are tested with THz radiation, the design considerations are applicable also to other regions of the electro-magnetic spectrum.

  10. Method for producing an isoplanatic aspheric monofocal intraocular lens, and resul ting lens

    OpenAIRE

    Barbero, Sergio; Marcos, Susana; Dorronsoro, Carlos; Montejo, Javier; Salazar Salegui, Pedro

    2010-01-01

    [EN] The invention can be used to obtain isoplanatic aspheric mono focal intraocular lenses in a viewing range of up to 25° (preferably up to 10°). The method comprises the following steps: l. mathematical defmition of an aphakic eye model; 2. mathematical definition of an intraocular lens model; 3. mathematical defmition of the implantation of the lens; 4. mathematical defmition of the merit function; 5. definition of the contour conditions; 6. defmition of a measurement for charact...

  11. Quality of vision in patients implanted with aspherical and spherical intraocular lens: Intraindividual comparison

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    Francesco Semeraro

    2014-01-01

    Full Text Available Aims: To compare the quality of vision in pseudophakic patients implanted with aspherical and spherical intraocular lenses (IOLs. Materials and Methods: Randomized prospective longitudinal intrapatient comparison between aspherical and spherical IOLs performed on 22 patients who underwent bilateral cataract surgery. Best corrected visual acuity, subjective contrast sensitivity, Strehl ratio and spherical aberrations (SA, and higher order wavefront aberrations for a 3.5 mm and a 6.0 mm pupil were measured after 3 months of cataract surgery. Results: SA (Z4,0 decreased significantly in eyes with aspherical IOL implant (P = 0.004. Modulation transfer function (MTF and point spread function (PSF resulted no significant difference between the two groups (P = 0.87; P = 0.32. Conclusion: Although the SA is significantly lower in eyes implanted with aspherical IOL, the quality of vision determined with MTF and PSF does not significantly differ for subjective and objective parameters that were analyzed.

  12. CUSTOM OPTIMIZATION OF INTRAOCULAR LENS ASPHERICITY

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    Koch, Douglas D.; Wang, Li

    2007-01-01

    Purpose To investigate the optimal amount of ocular spherical aberration (SA) in an intraocular lens (IOL) to maximize optical quality. Methods In 154 eyes of 94 patients aged 40 to 80 years, implantation of aspheric IOLs was simulated with different amounts of SA to produce residual ocular SA from −0.30 μm to +0.30 μm. Using the VOL-CT program (Sarver & Associates, Carbondale, Illinois), corneal wavefront aberrations up to 6th order were computed from corneal topographic elevation data (Humphrey Atlas, Carl Zeiss Meditec, Inc, Dublin, California). Using the ZernikeTool program (Advanced Medical Optics, Inc, Santa Ana, California), the polychromatic point spread function with Stiles-Crawford effect was calculated for the residual ocular higher-order aberrations (HOAs, 3rd to 6th order, 6-mm pupil), assuming fully corrected 2nd-order aberrations. Five parameters were used to quantify optical image quality, and we determined the residual ocular SA at which the maximal image quality was achieved for each eye. Stepwise multiple regression analysis was performed to assess the predictors for optimal SA of each eye. Results The optimal SA varied widely among eyes. Most eyes had best image quality with low amounts of negative SA. For modulation transfer function volume up to 15 cycles/degree, the amount of optimal SA could be predicted based on other HOAs of the cornea with coefficient of multiple determination (R2) of 79%. Eight Zernike terms significantly contributed to the optimal SA in this model; the order of importance to optimal SA from most to least was: Z60, Z62, Z42, Z53, Z64, Z3−1, Z33, and Z31. For the other 4 measures of visual quality, the coefficients of determination varied from 32% to 63%. Conclusion The amount of ocular SA producing best image quality varied widely among subjects and could be predicted based on corneal HOAs. Selection of an aspheric IOL should be customized according to the full spectrum of corneal HOAs and not 4th-order SA alone

  13. Towards customized intraocular lenses

    NARCIS (Netherlands)

    de Jong, Tim

    2017-01-01

    In the eye there are two refractive components that make light focus on the retina and let you see: the cornea and the lens. When a eye develops cataract the lens becomes caractarous and is removed and replaced with a synthetic intraocular lens during a cataract surgery procedure. Although there was

  14. Comparação da análise da frente de onda e da sensibilidade ao contraste em olhos pseudofácicos com implante de lentes intra-oculares esférica e asférica Wavefront analysis and contrast sensitivity comparison between spheric and aspheric intraocular lenses

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    Wilson Takashi Hida

    2008-06-01

    Full Text Available OBJETIVO: Comparar a análise da frente de onda e a sensibilidade de contraste pós-operatórias em pacientes submetidos à facoemulsificação com implante de lentes intra-oculares esféricas num olho e asféricas no olho contralateral. MÉTODOS: Este estudo prospectivo comparativo, randomizado, duplo-cego, incluiu 32 olhos de 16 pacientes. Uma avaliação oftalmológica completa foi realizada durante as visitas antes e depois da cirurgia (no primeiro, terceiro, sétimo, e nonagésimo dias pós-cirúrgicos, que incluiu acuidade visual, teste de sensibilidade ao contraste, aberrometria. Todos exames (menos aberrometr=ia foram feitos monocularmente com pupilas não dilatadas. Os pacientes foram submetidos a facectomia ultra-sônica convencional com implante de uma lente asférica SN60WF num olho e esférica SN60ATno outro. RESULTADOS: A acuidade visual média com a melhor correção foi -0,146 LogMAR no grupo da lente intra-ocular esférica, e -0.165 logMAR no grupo da lente intra-ocular asférica sob condições fotópicas, -0,003 LogMAR sob condições mesópicas. A sensibilidade ao contraste foi semelhante em ambos os grupos tanto em condições fotópicas e mesópicas. Em relação às aberrações ópticas ocorreu uma diferença significativa nas aberrações totais (1,09 ± 0,56 no grupo asférico e 1,52 ± 1,19 no grupo esférico e no componente esférico das aberrações de alta ordem(0,422 ± 0,202 no grupo asférico e 0,124 ± 0,087 no grupo esférico. CONCLUSÃO: As duas lentes intra-oculares promoveram uma excelente visão em situações de alto contraste, e os olhos implantados com a lente asférica tiveram menos aberrações totais e esféricas que aqueles implantados com a lente esférica.PURPOSE: Compare the wavefront and contrast sensitivity of bilateral pseudophakic patients with aspheric in one eye and spheric intraocular lenses in the other. METHODS: This prospective, comparative, randomized study, double masked, included 32

  15. From Spheric to Aspheric Solid Polymer Lenses: A Review

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    Kuo-Yung Hung

    2011-01-01

    Full Text Available This paper presents a new approach in the use of MEMS technology to fabricate micro-optofluidic polymer solid lenses in order to achieve the desired profile, focal length, numerical aperture, and spot size. The resulting polymer solid lenses can be applied in optical data storage systems, imaging systems, and automated optical inspection systems. In order to meet the various needs of different applications, polymer solid lenses may have a spherical or aspherical shape. The method of fabricating polymer solid lenses is different from methods used to fabricate tunable lenses with variable focal length or needing an external control system to change the lens geometry. The current trend in polymer solid lenses is toward the fabrication of microlenses with a high numerical aperture, small clear aperture (<2 mm, and high transmittance. In this paper we focus on the use of thermal energy and electrostatic force in shaping the lens profile, including both spherical and aspherical lenses. In addition, the paper discusses how to fabricate a lens with a high numerical aperture of 0.6 using MEMS and also compares the optical characteristics of polymer lens materials, including SU-8, Norland Optical Adhesive (NOA, and cyclic olefin copolymer (COC. Finally, new concepts and applications related to micro-optofluidic lenses and polymer materials are also discussed.

  16. Incoherently combining logarithmic aspheric lenses for extended depth of field.

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    Chu, Kaiqin; George, Nicholas; Chi, Wanli

    2009-10-01

    We describe a method for combining concentric logarithmic aspheric lenses in order to obtain an extended depth of field. Substantial improvement in extending the depth of field is obtained by carefully controlling the optical path difference among the concentric lenses so that their outputs combine incoherently. The system is analyzed through diffraction theory and the point spread function is shown to be highly invariant over a long range of object distances. After testing the image performance on a three-dimensional scene, we found that the incoherently combined logarithmic aspheres can provide a high-quality image over an axial distance corresponding to a defocus of +/- 14(lambda/4). Studies of the images of two-point objects are presented to illustrate the resolution of these lenses.

  17. Optical and visual performance of aspheric soft contact lenses.

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    Efron, Suzanne; Efron, Nathan; Morgan, Philip B

    2008-03-01

    This study was conducted to investigate whether aspheric design soft contact lenses reduce ocular aberrations and result in better visual acuity and subjective appreciation of clinical performance compared with spherical soft contact lenses. A unilateral, double-masked, randomized and controlled study was undertaken in which ocular aberrations and high and low contrast logMAR visual acuity were measured on myopic subjects who wore aspheric design (Biomedics 55 Evolution, CooperVision) and spherical design (Biomedics 55, CooperVision) soft contact lenses. Ten subjects who had about -2.00 D myopia wore -2.00 D lenses and 10 subjects who had about -5.00 D myopia wore -5.00 D lenses. Measurements were made under photopic and mesopic lighting conditions. Subjects were invited to grade comfort, vision in photopic and mesopic conditions, and overall impression with the two lens types on 100 unit visual analogue scales. There was no significant difference in high contrast or low contrast visual acuity between the two lens designs of either power under photopic or mesopic conditions. Both lens designs displayed lower levels of spherical aberration compared with the "no lens" condition under photopic and mesopic light levels (p designs. There were no statistically significant differences in subjective appreciation of clinical performance between lens designs or lens powers. At least with respect to the brand of lenses tested, the fitting of aspheric design soft contact lenses does not result in superior visual acuity, aberration control, or subjective appreciation compared with equivalent spherical design soft contact lenses.

  18. The efficiency of aspheric intraocular lens according to biometric measurements.

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    Whang, Woong-Joo; Piao, Junjie; Yoo, Young-Sik; Joo, Choun-Ki; Yoon, Geunyoung

    2017-01-01

    To analyze internal spherical aberration in pseudophakic eyes that underwent aspheric intraocular lens (IOL) implantation, and to investigate the relationships between biometric data and the effectiveness of aspheric IOL implantation. This retrospective study included 40 eyes of 40 patients who underwent implantation of an IOL having a negative spherical aberration of -0.20 μm (CT ASPHINA 509M; Carl Zeiss Meditec Inc., Germany). The IOLMaster (version 5.0; Carl Zeiss AG, Germany) was used for preoperative biometric measurements (axial length, anterior chamber depth, central corneal power) and the measurement of postoperative anterior chamber depth. The spherical aberrations were measured preoperatively and 3 months postoperatively using the iTrace (Tracey Technologies, Houston, TX, USA) at a pupil diameter of 5.0 mm. We investigated the relationships between preoperative biometric data and postoperative internal spherical aberration, and compared biometric measurements between 2 subgroups stratified according to internal spherical aberration (spherical aberration ≤ -0.06 μm vs. spherical aberration > -0.06 μm). The mean postoperative internal spherical aberration was -0.087 ± 0.063 μm. Preoperative axial length and residual total spherical aberration showed statistically significant correlations with internal spherical aberration (p = 0.041, 0.002). Preoperative axial length, postoperative anterior chamber depth, IOL power, and residual spherical aberration showed significant differences between the 2 subgroups stratified according to internal spherical aberration (p = 0.020, 0.029, 0.048, 0.041 respectively). The corrective effect of an aspheric IOL is influenced by preoperative axial length and postoperative anterior chamber depth. Not only the amount of negative spherical aberration on the IOL surface but also the preoperative axial length should be considered to optimize spherical aberration after aspheric IOL implantation.

  19. Some aspects of powerful lasers and aspheric lenses design

    International Nuclear Information System (INIS)

    Metz, Jean de

    1976-01-01

    Gigawatt power glass lasers are described. Geometrical, interferometric, coherence and focusing aspects of the beam are measured. Design of disc amplifier is shown with high gain glass. Aspheric lenses are designed and tested for focussing these beams. Experiments of multi-breakdown in gas are done. We get fusion in plasma made by second harmonic frequency of our 1.06 μ beam. Effect of self-focussing on laser beam quality is studied. (author) [fr

  20. Effect of aspherical and yellow tinted intraocular lens on blue-on-yellow perimetry

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    Rodrigo França de Espíndola

    2012-10-01

    Full Text Available PURPOSE: To investigate the possible effect of aspherical or yellow tinted intraocular lens (IOL on contrast sensitivity and blue-on-yellow perimetry. METHODS: This prospective randomized bilateral double-masked clinical study included 52 patients with visually significant bilateral cataracts divided in two groups; 25 patients (50 eyes received aspherical intraocular lens in one eye and spherical intraocular lens in the fellow eye; and 27 patients (54 eyes received ultraviolet and blue light filter (yellow tinted IOL implantation in one eye and acrylic ultraviolet filter IOL in the fellow eye. The primary outcome measures were contrast sensitivity and blue-on-yellow perimetry values (mean deviation [MD] and pattern standard deviation [PSD] investigated two years after surgery. The results were compared intra-individually. RESULTS: There was a statistically significant between-group (aspherical and spherical intraocular lens difference in contrast sensitivity under photopic conditions at 12 cycles per degree and under mesopic conditions at all spatial frequencies. There were no between-group significant differences (yellow tinted and clear intraocular lens under photopic or mesopic conditions. There was no statistically significant difference between all intraocular lens in MD or PSD. CONCLUSION: Contrast sensitivity was better under mesopic conditions with aspherical intraocular lens. Blue-on-yellow perimetry did not appear to be affected by aspherical or yellow tinted intraocular lens. Further studies with a larger sample should be carried out to confirm or not that hypotheses.

  1. Refractive lens exchange with a multifocal diffractive aspheric intraocular lens

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    Teresa Ferrer-Blasco

    2012-06-01

    Full Text Available PURPOSE: To evaluate the safety, efficacy and predictability after refractive lens exchange with multifocal diffractive aspheric intraocular lens implantation. METHODS: Sixty eyes of 30 patients underwent bilateral implantation with AcrySof® ReSTOR® SN6AD3 intraocular lens with +4.00 D near addition. Patients were divided into myopic and hyperopic groups. Monocular best corrected visual acuity at distance and near and monocular uncorrected visual acuity at distance and near were measured before and 6 months postoperatively. RESULTS: After surgery, uncorrected visual acuity was 0.08 ± 0.15 and 0.11 ± 0.14 logMAR for the myopic and hyperopic groups, respectively (50% and 46.67% of patients had an uncorrected visual acuity of 20/20 or better in the myopic and hyperopic groups, respectively. The safety and efficacy indexes were 1.05 and 0.88 for the myopic and 1.01 and 0.86 for the hyperopic groups at distance vision. Within the myopic group, 20 eyes remained unchanged after the surgery, and 3 gained >2 lines of best corrected visual acuity. For the hyperopic group, 2 eyes lost 2 lines of best corrected visual acuity, 21 did not change, and 3 eyes gained 2 lines. At near vision, the safety and efficacy indexes were 1.23 and 1.17 for the myopic and 1.16 and 1.13 for the hyperopic groups. Best corrected near visual acuity improved after surgery in both groups (from 0.10 logMAR to 0.01 logMAR in the myopic group, and from 0.10 logMAR to 0.04 logMAR in the hyperopic group. CONCLUSIONS: The ReSTOR® SN6AD3 intraocular lens in refractive lens exchange demonstrated good safety, efficacy, and predictability in correcting high ametropia and presbyopia.

  2. DESIGN OF THE MULTIORDER INTRAOCULAR LENSES

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    V. G. Kolobrodov

    2015-01-01

    Full Text Available Intraocular lenses (IOLs are used to replace the natural crystalline lens of the eye. Just few basic designs of IOLs are used clinically. Multiorder diffractive lenses (MODL which operate simultaneously in several diffractive orders were proposed to decrease the chromatic aberration. Properties analysis of MODL showed a possibility to use them to develop new designs of IOLs. The purpose of this paper was to develop a new method of designing of multiorder intraocular lenses with decreased chromatic aberration. The theoretical research of the lens properties was carried out. The diffraction efficiency dependence with the change of wavelength was studied. A computer simulation of MODL in a schematic model of the human eye was carried out. It is found the capability of the multiorder diffractive lenses to focus polychromatic light into a segment on the optical axis with high diffraction efficiency. At each point of the segment is present each component of the spectral range, which will build a color image in combination. The paper describes the new design method of intraocular lenses with reduced chromaticism and with endless adaptation. An optical system of an eye with an intraocular lens that provides sharp vision of objects located at a distance of 700 mm to infinity is modeled.

  3. Application of diffractive aspheric multifocal intraocular lens in the Uighur in phacoemulsification

    Directory of Open Access Journals (Sweden)

    Nuersimanguli·Mijiti

    2016-05-01

    Full Text Available AIM:To research the efficacy and safety of diffractive aspheric multifocal intraocular lens(MIOLin the Uighur in phacoemulsification to provide guidance for the clinical treatment of cataracts patients in Xinjiang region. METHODS:Two hundred and twenty-eight Uygur patients(280 eyesreceived phacoemulsification from April 2012 to March 2013 were randomly divided into multifocal group(106 cases with 146 eyesand monofocal group(122 cases with 134 eyes. Patients were followed up for 3mo. The intraocular pressure(IOP, uncorrected distance visual acuity, uncorrected near vision, best-corrected distance visual acuity and best corrected near vision were measured. The delensed rate, visual quality, and satisfaction for lenses in the form of questionnaires were compared. RESULTS:Multifocal group was better on the uncorrected near vision than monofocal group(PP>0.05. The contrast sensitivity of multifocal group under scotopia at spatial frequency 3c/d was lower than that of monofocal group(PP>0.05. Delensed rate of multifocal group was higher than that of monofocal group(PP>0.05.CONCLUSION:MIOL with phacoemulsification can provide patient good full range vision, especially on good near vision. The patients with MIOL implanted have a higher delensed rate, less postoperative adverse symptoms, quicker recovery and satisfaction.

  4. Customized computer models of eyes with intraocular lenses.

    Science.gov (United States)

    Rosales, P; Marcos, S

    2007-03-05

    We compared experimental wave aberrations in pseudophakic eyes with aspheric intraocular lenses (IOLs) to simulate aberrations from numerical ray tracing on customized computer eye models using corneal topography, angle lambda, ocular biometry, IOL geometry, and IOL tilt and decentration measured on the same eyes. We found high correlations between real and simulated aberrations even for the eye with only the cornea, and these increased on average when the IOL geometry and position were included. Relevant individual aberrations were well predicted by the complete eye model. Corneal spherical aberration and horizontal coma were compensated by the IOL, and in 58.3% of the cases IOL tilt and decentration contributed to compensation of horizontal coma. We conclude that customized computer eye models are a good representation of real eyes with IOLs and allow understanding of the relative contribution of optical, geometrical and surgically-related factors to image quality. Corneal spherical aberration is reduced by aspheric IOLs, although other corneal high order aberrations are still a major contributor to total aberrations in pseudophakic eyes. Tilt and decentration of the IOLs represent a relatively minor contribution of the overall optical quality of the eye.

  5. Optimizing outcomes with multifocal intraocular lenses

    Directory of Open Access Journals (Sweden)

    Gitansha Shreyas Sachdev

    2017-01-01

    Full Text Available Modern day cataract surgery is evolving from a visual restorative to a refractive procedure. The advent of multifocal intraocular lenses (MFIOLs allows greater spectacle independence and increased quality of life postoperatively. Since the inception in 1980s, MFIOLs have undergone various technical advancements including trifocal and extended depth of vision implants more recently. A thorough preoperative workup including the patients' visual needs and inherent ocular anatomy allows us to achieve superior outcomes. This review offers a comprehensive overview of the various types of MFIOLs and principles of optimizing outcomes through a comprehensive preoperative screening and management of postoperative complications.

  6. [Halos and multifocal intraocular lenses: origin and interpretation].

    Science.gov (United States)

    Alba-Bueno, F; Vega, F; Millán, M S

    2014-10-01

    To present the theoretical and experimental characterization of the halo in multifocal intraocular lenses (MIOL). The origin of the halo in a MIOL is the overlaying of 2 or more images. Using geometrical optics, it can be demonstrated that the diameter of each halo depends on the addition of the lens (ΔP), the base power (P(d)), and the diameter of the IOL that contributes to the «non-focused» focus. In the image plane that corresponds to the distance focus, the halo diameter (δH(d)) is given by: δH(d)=d(pn) ΔP/P(d), where d(pn) is the diameter of the IOL that contributes to the near focus. Analogously, in the near image plane the halo diameter (δH(n)) is: δH(n)=d(pd) ΔP/P(d), where d(pd) is the diameter of the IOL that contributes to the distance focus. Patients perceive halos when they see bright objects over a relatively dark background. In vitro, the halo can be characterized by analyzing the intensity profile of the image of a pinhole that is focused by each of the foci of a MIOL. A comparison has been made between the halos induced by different MIOL of the same base power (20D) in an optical bench. As predicted by theory, the larger the addition of the MIOL, the larger the halo diameter. For large pupils and with MIOL with similar aspheric designs and addition (SN6AD3 vs ZMA00), the apodized MIOL has a smaller halo diameter than a non-apodized one in distance vision, while in near vision the size is very similar, but the relative intensity is higher in the apodized MIOL. When comparing lenses with the same diffractive design, but with different spherical-aspheric base design (SN60D3 vs SN6AD3), the halo in distance vision of the spherical MIOL is larger, while in near vision the spherical IOL induces a smaller halo, but with higher intensity due to the spherical aberration of the distance focus in the near image. In the case of a trifocal-diffractive IOL (AT LISA 839MP) the most noticeable characteristic is the double-halo formation due to the 2 non

  7. Mechanical properties of intra-ocular lenses

    Science.gov (United States)

    Ehrmann, Klaus; Kim, Eon; Parel, Jean-Marie

    2008-02-01

    Cataract surgery usually involves the replacement of the natural crystalline lens with a rigid or foldable intraocular lens to restore clear vision for the patient. While great efforts have been placed on optimising the shape and optical characteristics of IOLs, little is know about the mechanical properties of these devices and how they interact with the capsular bag once implanted. Mechanical properties measurements were performed on 8 of the most commonly implanted IOLs using a custom build micro tensometer. Measurement data will be presented for the stiffness of the haptic elements, the buckling resistance of foldable IOLs, the dynamic behaviour of the different lens materials and the axial compressibility. The biggest difference between the lens types was found between one-piece and 3-piece lenses with respect to the flexibility of the haptic elements

  8. Influence of aspheric intraocular lens on frequency doubling technology and contrast sensitivity: a fellow eye study

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    Rodrigo França de Espíndola

    2014-12-01

    Full Text Available Purpose: To evaluate whether implantation of an aspheric intraocular lens (IOL results in reduced ocular aberrations and improved contrast sensitivity after cataract surgery and, therefore, changes on frequency-doubling technology (FDT testing. Methods: The present prospective clinical study enrolled 25 patients with bilateral cataract (50 eyes, who randomly received either an aspheric (Akreos AO or a spherical (Akreos Fit IOL in one eye and the other IOL in the second eye. Assessment 12 months postoperatively included photopic and mesopic contrast sensitivity testing. Higher-order aberrations (HOAs were computed. FDT testing was divided into four areas to evaluate the variation of the values at different points. The median values of the local pattern thresholds (median area contrast sensitivity [MACS] obtained with that division were calculated. Results: The Akreos AO group obtained statistically significantly lower values of HOAs and spherical aberration compared with the Akreos Fit group. There was a statistically significant between-group difference in contrast sensitivity under mesopic conditions at all spatial frequencies. No statistically significant differences were observed in mean deviation and pattern standard deviation. The aspheric IOL exhibited higher MACS in all areas, although a statistically significant difference was reached only in the 20-degree field area (P=0.043. Conclusion: Aspheric IOLs significantly reduced spherical aberration and HOAs, improving mesopic contrast sensitivity. Although there was a trend toward slightly improved FDT in the aspheric IOL group, it was not statistically significant.

  9. A feasible injection molding technique for the manufacturing of large diameter aspheric plastic lenses

    Science.gov (United States)

    Shieh, Jen-Yu; Wang, Luke K.; Ke, Shih-Ying

    2010-07-01

    A computer aided engineering (CAE) tool-assisted technique, using Moldex3D and aspheric analysis utility (AAU) software in a polycarbonate injection molding design, is proposed to manufacture large diameter aspheric plastic lenses. An experiment is conducted to verify the applicability/feasibility of the proposed technique. Using the preceding two software tools, these crucial process parameters associated with the surface profile errors and birefringence of a molded lens can be attainable. The strategy adopted here is to use the actual quantity of shrinkage after an injection molding trial of an aspherical plastic lens as a reference to perform the core shaping job while keeping the coefficients of aspheric surface, radius, and conic constant unchanged. The design philosophy is characterized by using the CAE tool as a guideline to pursue the best symmetry condition, followed by injection molding trials, to accelerate a product’s developmental time. The advantages are less design complexity and shorter developmental time for a product.

  10. Contrast visual acuity after multifocal intraocular lens implantation:aspheric versus spherical design

    Directory of Open Access Journals (Sweden)

    Jun-Hua Li

    2014-02-01

    Full Text Available AIM: To evaluate contrast visual acuity (CVA after implantation of an aspheric apodized diffractive intraocular lens (IOL or a spherical apodized diffractive IOL in cataract surgery.METHOD: This prospective randomized controlled study with a 12-month follow-up compared the results of cataract surgery with implantation of an aspheric AcrySof ReSTOR SN6AD3 IOL (30 eyes and a spherical AcrySof ReSTOR SN60D3 IOL (30 eyes. CVA with best distance correction was measured at 4 contrast levels (100%, 25%, 10% and 5% under 3 levels of chart luminance [250, 85 and 25 candelas per square meter (cd/m2] using a multi-functional visual acuity tester (MFVA-100.RESULTS:At 12 months after surgery, there were no statistically significant differences in 100% CVA and 25% CVA under 250cd/m2 (P100%=0.875 and P25%=0.057 and 85cd/m2 (P100%=0.198 and P25%=0.193 between the aspheric group and the spherical group. However, the 10% CVA and 5% CVA were significant better in aspheric group than spherical group under 250cd/m2 (P10%=0.042 and P5%=0.007 and 85cd/m2 (P10%=0.002 and P5%=0.039. Under the luminance level of 25cd/m2, no significant differences was found in the 100% CVA between the 2 group (P100%=0.245, while aspheric group had better visual acuity in the remaining 3 contracts (P25%=0.023, P10%=0.026 and P5%=0.002, respectively.CONCULSION:The aspheric AcrySof ReSTOR SN6AD3 IOL provided patients with better low-contrast visual acuity than the spherical AcrySof ReSTOR SN60D3 IOL.Keyword:cataract surgery; intraocular lens; contrast sensitivity; visual acuity

  11. Contrast sensitivity after refractive lens exchange with a multifocal diffractive aspheric intraocular lens

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    Teresa Ferrer-Blasco

    2013-04-01

    Full Text Available PURPOSE: To evaluate distance and near contrast sensitivity (CS under photopic and mesopic conditions before and after refractive lens exchange (RLE and implantation of the aspheric AcrySof®ReSTOR® (SN6AD3 model intraocular lens (IOL. METHODS:Seventy-four eyes of 37 patients after RLE underwent bilateral implantation with the aspheric AcrySof ReSTOR IOL. The patient sample was divided into myopic and hyperopic groups. Monocular uncorrected visual acuity at distance and near (UCVA and UCNVA, respectively and monocular best corrected visual acuity at distance and near (BCVA and BCNVA, respectively were measured before and 6 months postoperatively. Monocular CS function was measured at three different luminance levels (85, 5 and 2.5 cd/m² before and after RLE. Post-implantation results at 6 months were compared with those found before surgery. RESULTS: Our results revealed that patients in both groups obtained good UCVA and BCVA after RLE at distance and near vision in relation to pre-surgery values. No statistically significant differences were found between the values of CS pre and post-RLE at distance and near, at any lighting condition and spatial frequency (p>0.002. CONCLUSIONS: Refractive lens exchange with aspheric AcrySof ReSTOR IOL in myopic and hyperopic population provided good visual function and yield good distance and near CS under photopic and mesopic conditions.

  12. Influence of corneal asphericity on the refractive outcome of intraocular lens implantation in cataract surgery.

    Science.gov (United States)

    Savini, Giacomo; Hoffer, Kenneth J; Barboni, Piero

    2015-04-01

    To evaluate the possible influence of anterior corneal surface asphericity on the refractive outcomes in eyes having intraocular lens (IOL) implantation after cataract surgery. Fondazione G.B. Bietti IRCCS, Rome, Italy. Retrospective comparative case series. Intraocular lens power was calculated using the Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. Asphericity (Q-value) was measured at 8.0 mm with a Placido-disk corneal topographer (Keratron), a rotating Scheimpflug camera (Pentacam), and a rotating Scheimpflug camera combined with Placido-disk corneal topography (Sirius). The relationship between the error in refraction prediction (ie, difference between expected refraction and refraction measured 1 month after surgery) and the Q-value was assessed by linear regression. The same IOL model (Acrysof SA60AT) was implanted in 115 eyes of 115 consecutive patients. Regression analysis showed a statistically significant relationship between the error in refraction prediction and the Q-value with all formulas and all devices. In all cases, a more negative Q-value (prolate cornea) was associated with a myopic outcome, whereas a more positive Q-value (oblate cornea) was associated with a hyperopic outcome. The highest coefficient of determination was detected between the Hoffer Q formula and the Placido-disk corneal topographer (R(2) = 0.2630), for which the error in refraction prediction (y) was related to the Q-value (x) according to the formula y = -0.2641 + 1.4589 × x. Corneal asphericity influences the refractive outcomes of IOL implantation and should be taken into consideration when using third-generation IOL power formulas. Dr. Hoffer receives book royalties from Slack, Inc., Thorofare, New Jersey, and formula royalties from all manufacturers using the Hoffer Q formula. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  13. Computerized calculation scheme for toric intraocular lenses.

    Science.gov (United States)

    Langenbucher, Achim; Seitz, Berthold

    2004-06-01

    While a number of intraocular lens (IOL) power prediction formulae are well established for determination of spherical lenses, no common strategy has been published for the computation of toric IOLs. The purpose of this study is to describe a paraxial computing scheme for tracing an axial pencil of rays through the 'optical system eye' containing astigmatic refractive surfaces with their axes at random. The capabilities of this computing scheme are demonstrated with clinical examples. Based on a schematic model eye with spherocylindric surfaces, we use two alternative notations for description of vergences or prescriptions: (1) standard notation (refraction in both cardinal meridians and axis), and (2) component notation (spherical equivalent and cylindric component in 0 degrees and 45 degrees. Refractive surfaces are added to the vergence in component notation, whereas the transformation of the vergence through media is performed in the standard notation for both cardinal meridians. For calculation of the toric lens implant, a pencil of rays is traced through the spectacle and the cornea to the estimated lens position as well as backwards from the retina to the estimated lens position. For calculation of residual spectacle refraction, a pencil of rays is traced backwards from the retina through the toric lens implant and the cornea to the spectacle plane. In example 1 we calculate a 'thin toric lens' for compensation of a corneal astigmatism to achieve a spherical target refraction. In example 2 we compute a 'thick toric lens', which has to compensate for an oblique corneal astigmatism and rotate the spectacle cylinder to the against the rule position to enhance near vision. In example 3 we estimate the residual refraction at the corneal plane after implantation of a thick toric lens, when the cylinder of the lens implant is compensating the corneal cylinder in part and the axis of implantation is not fully aligned with the axis of the corneal astigmatism. This

  14. Bilateral spontaneous subluxation of scleral-fixated intraocular lenses.

    Science.gov (United States)

    Assia, Ehud I; Nemet, Arie; Sachs, Dani

    2002-12-01

    Two young men with primary ectopic lenses had intracapsular cataract extraction and scleral fixation of posterior chamber intraocular lenses (PC IOLs) using 10-0 polypropylene sutures tied to the IOL eyelets. Three to 9 years after implantation, spontaneous IOL vertical subluxation occurred in all 4 eyes (5 IOL loops), probably because of suture breakage. Late subluxation of a sutured IOL may occur several years after implantation. Double fixation and thicker sutures should be considered, especially in young patients.

  15. Antireflection coatings for intraocular lenses of sapphire and fianite

    Energy Technology Data Exchange (ETDEWEB)

    Babin, A.A.; Konoplev, Yu.N.; Mamaev, Yu.A. [Inst. of Applied Physics, Nizhnii Novgorod (Russian Federation)] [and others

    1995-10-01

    Broadband antireflection coatings for intraocular lenses of sapphire and fianite are calculated and implemented practically. Their residual reflectance in the liquid with a refracting index of 1.336 is below 0.2% from each face virtually over the entire visible region. 7 refs., 2 figs., 2 tabs.

  16. Extreme depth-of-field intraocular lenses

    Science.gov (United States)

    Baker, Kenneth M.

    1996-05-01

    A new technology brings the full aperture single vision pseudophakic eye's effective hyperfocal distance within the half-meter range. A modulated index IOL containing a subsurface zeroth order coherent microlenticular mosaic defined by an index gradient adds a normalizing function to the vergences or parallactic angles of incoming light rays subtended from field object points and redirects them, in the case of near-field images, to that of far-field images. Along with a scalar reduction of the IOL's linear focal range, this results in an extreme depth of field with a narrow depth of focus and avoids the focal split-up, halo, and inherent reduction in contrast of multifocal IOLs. A high microlenticular spatial frequency, which, while still retaining an anisotropic medium, results in a nearly total zeroth order propagation throughout the visible spectrum. The curved lens surfaces still provide most of the refractive power of the IOL, and the unique holographic fabrication technology is especially suitable not only for IOLs but also for contact lenses, artificial corneas, and miniature lens elements for cameras and other optical devices.

  17. Magnetic resonance imaging diagnosis of intraocular lenses. Die kernspintomographische Diagnostik der Hinterkammerlinse

    Energy Technology Data Exchange (ETDEWEB)

    Tosch, U. (Strahlenklinik und Poliklinik, Universitaetsklinik Rudolf Virchow, Berlin (Germany)); Bleckmann, H. (Strahlenklinik und Poliklinik, Universitaetsklinik Rudolf Virchow, Berlin (Germany)); Kaczmarek, U. (Strahlenklinik und Poliklinik, Universitaetsklinik Rudolf Virchow, Berlin (Germany))

    1994-09-01

    Intraocular lenses were investigated by MRI to obtain information about the quality of this method. In experimental studies, seven lenses of between 0 and 30 diopters were visualized. By MRI it was possible to differentiate the various diameters of lenses. It was not possible to discriminate the material of the intraocular lenses. After these first studies the eyes of two corpses and eight patients were investigated. Because of the resolution of MRI it was possible to tell the diopter of implanted lenses. However, by use of MRI in the regular position, a tilting or decentration of the intraocular lens was demonstrated. (orig.)

  18. Effect of transscleral neodymium: YAG cyclophotocoagulation on intraocular lenses

    Energy Technology Data Exchange (ETDEWEB)

    Blomquist, P.H.; Gross, R.L.; Koch, D.D. (Baylor College of Medicine, Houston, TX (USA))

    1990-03-01

    A neodymium: YAG laser operating in the thermal mode was used to irradiate isolated intraocular lenses (IOLs) and to perform transscleral cyclophotocoagulation on pseudophakic autopsy eyes to investigate the potential damage to IOL haptics such irradiation may cause. In the isolated IOLs, 70 mJ of energy deformed and partially melted both polymethylmethacrylate (PMMA) and polypropylene haptics. One of the capsular-fixated PC-IOL haptics in an autopsy eye partially melted when irradiated with the maximum energy level (8.8 J), with the aiming beam focused 1 mm posterior to the limbus and maximal posterior focus offset.

  19. [Scheimpflug photography for the examination of phakic intraocular lenses].

    Science.gov (United States)

    Baumeister, M

    2014-10-01

    High myopia phakic intraocular lenses (IOL) have become an established means of surgical correction for high ametropia. Scheimpflug photography is one of the methods which are frequently applied for postoperative examination of the implants. Results from published studies employing Scheimpflug photography for examination of anterior chamber angle-fixated, iris-fixated and sulcus-fixated phakic IOLs were evaluated. In several published studies Scheimpflug photography was used to examine the position of the implant and opacification of the crystalline lens. The results provided valuable evidence for the improvement of phakic IOL design. Scheimpflug photography offers an easy to use, rapid non-contact examination of phakic IOLs.

  20. The Effect of Various Contact Lenses on Intraocular Pressure Measurement by Goldman Tonometer

    Directory of Open Access Journals (Sweden)

    Monireh Mahjoob

    2014-06-01

    Full Text Available Background: Today, contact lenses have extensive usages. Contact lens places on cornea, so it may induce variation on cornea and these variations can influence the measurement of intraocular pressure (IOP by Goldman tonometer. The aim of this research was to study the effect of various contact lenses on measurement of intraocular pressure by Goldman tonometer. Materials and Methods: In this study, 80 subjects aged 18-25 were selected randomly among patients of Al-Zahra ophthalmology center. None of them has any eye pathological problems. Before wearing the lens, intraocular pressure was measured, and then patients were divided into two groups of soft and hard contact lenses. Soft and hard contact lenses were placed on the eye for two hours, and the intraocular pressure was measured again. Results: The mean of IOP before wearing contact lenses and two hours later was 15.96 mmHg and 13.93, s respectively. Paired test showed a significant difference between IOP before and after wearing contact lenses (p=0.001.There was no significant differences in mean of intraocular pressure decline before and after placing the contact lens in both soft and hard lenses. Conclusion: According to this study, the intraocular pressure decreases after wearing contact lenses (CL. This decline may be due to variation in properties of cornea after wearing CL that can also affect IOP measurement.

  1. A simple technique of intraocular lenses explantation for single-piece foldable lenses

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    Arup Bhaumik

    2017-01-01

    Full Text Available Foldable intraocular lenses (IOLs are most commonly used in modern-day cataract surgery. Explantation of these IOLs is not frequently encountered, but sometimes extreme situations may demand the same. Commonly explantation is achieved by bisecting the IOL inside the anterior chamber with a cutter and delivering the pieces out one by one. This may require corneal wound extension with associated damage and endothelial loss leading to visual deterioration. We devised a simple, innovative IOL explantation technique utilizing a modified Alcon A cartridge and snare. This can successfully refold the IOL to be explanted inside the eye and deliver it out through the same wound. The device has limitations with very thick optic lenses, multipiece, and silicon IOLs. In conclusion, we describe a simple, innovative, and reproducible technique to explant almost any single piece IOL without compromising the original surgery and yielding very satisfactory outcomes.

  2. Straylight from glistenings in intraocular lenses : In vitro study

    NARCIS (Netherlands)

    Łabuz, Grzegorz; Reus, Nicolaas J; van den Berg, Thomas J T P

    PURPOSE: To assess light scattering from intraocular lenses (IOLs) with different numbers of laboratory-induced glistenings and create a model for predicting glistening effects on straylight. SETTING: Rotterdam Ophthalmic Institute, Rotterdam, the Netherlands. DESIGN: Experimental study. METHODS:

  3. The effect of ionizing radiation on intraocular lenses

    International Nuclear Information System (INIS)

    Ellerin, Bruce E.; Nisce, Lourdes Z.; Roberts, Calvin W.; Thornell, Cliff; Sabbas, Albert; Wang Huili; Li, P. Mark; Nori, Dattatreyudu

    2001-01-01

    Background: The native crystalline lens is the principal shield against ultraviolet radiation (UV), damage to the human retina. Every year in the United States, more than one million patients undergo removal of the natural lens in the course of cataract surgery (phakectomy), at which time an intraocular lens (IOL) is placed in the lens capsule. The IOL thenceforth serves as the principal barrier to ultraviolet radiation over the life of the implant, potentially for decades. The synthetic organic molecules of which IOLs are composed offer little UV protection unless ultraviolet-absorbing chromophores are incorporated into the lens material during manufacture. However, chromophores are alkenes potentially subject to radiolytic degradation. It is unknown whether ionizing radiation at clinical doses (e.g., to the brain or in the head-and-neck region) affects the UV-absorbing capacity of chromophore-bearing IOLs and consequently exposes the retina to potentially chronic UV damage. In addition, the polymers of which IOLs are composed are themselves subject to radiation damage, which theoretically might result in optical distortion in the visible light range. Objective: To determine whether megavoltage photon ionizing radiation alters the absorption spectra of ultraviolet-shielding polymethylmethacrylate (PMMA) and organopolysiloxane (silicone) intraocular lenses (IOLs) in the UV (280 nm ≤ λ < 400 nm), visible (400 nm ≤ λ ≤ 700 nm), and low-end near-infrared (700 nm < λ ≤ 830 nm) ranges. Design: Prospective, nonrandomized trial of dose-paired IOL cohorts. Methods: Fourteen IOLs, seven of PMMA (Chiron 6842B) and seven of silicone (IOLAB L141U), were paired and examined for absorption spectra in 1-nm intervals over the range λ = 280-830 nm on a Cary 400 deuterium and quartz halogen source-lamp UV/visible spectrophotometer before and after undergoing megavoltage ionizing irradiation to doses of 2, 5, 10, 20, 40, 60, and 100 Gray, respectively. Because of

  4. Clinical Evaluation of Functional Vision of +1.5 Diopters near Addition, Aspheric, Rotational Asymmetric Multifocal Intraocular Lens.

    Science.gov (United States)

    Kretz, Florian Tobias Alwin; Khoramnia, Rahmin; Attia, Mary Safwat; Koss, Michael Janusz; Linz, Katharina; Auffarth, Gerd Uwe

    2016-10-01

    To evaluate postoperative outcomes and visual performance in intermediate distance after implantation of a +1.5 diopters (D) addition, aspheric, rotational asymmetric multifocal intraocular lens (MIOL). Patients underwent bilateral cataract surgery with implantation of an aspheric, asymmetric MIOL with +1.5 D near addition. A complete ophthalmological examination was performed preoperatively and 3 months postoperatively. The main outcome measures were monocular and binocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), distance corrected intermediate visual acuity (DCIVA), uncorrected near visual acuity (UNVA) and distance corrected keratometry, and manifest refraction. The Salzburg Reading Desk was used to analyze unilateral and bilateral functional vision with uncorrected and corrected reading acuity, reading distance, reading speed, and the smallest log-scaled print size that could be read effectively at near and intermediate distances. The study comprised 60 eyes of 30 patients (mean age, 68.30 ± 9.26 years; range, 34 to 80 years). There was significant improvement in UDVA and CDVA. Mean UIVA was 0.01 ± 0.09 logarithm of the minimum angle of resolution (logMAR) and mean DCIVA was -0.02 ± 0.11 logMAR. In Salzburg Reading Desk analysis for UIVA, the mean subjective intermediate distance was 67.58 ± 8.59 cm with mean UIVA of -0.02 ± 0.09 logMAR and mean word count of 96.38 ± 28.32 words/min. The new aspheric, asymmetric, +1.5 D near addition MIOL offers good results for distance visual function in combination with good performance for intermediate distances and functional results for near distance.

  5. Multifocal versus monofocal intraocular lenses after cataract extraction

    Directory of Open Access Journals (Sweden)

    Daniel Calladine

    Full Text Available BACKGROUND: Good unaided distance visual acuity is now a realistic expectation following cataract surgery and intraocular lens (IOL implantation. Near vision, however, still requires additional refractive power, usually in the form of reading glasses. Multiple optic (multifocal IOLs are available which claim to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal IOLs. OBJECTIVES: The objective of this review was to assess the effects of multifocal IOLs, including effects on visual acuity, subjective visual satisfaction, spectacle dependence, glare and contrast sensitivity, compared to standard monofocal lenses in people undergoing cataract surgery. METHODS: Search methods: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register, The Cochrane Library 2012, Issue 2, MEDLINE (January 1946 to March 2012, EMBASE (January 1980 to March 2012, the metaRegister of Controlled Trials (mRCT (www.controlled-trials.com, ClinicalTrials.gov (www.clinicaltrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP (www.who.int/ictrp/search/en. We did not use any date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 6 March 2012. We searched the reference lists of relevant articles and contacted investigators of included studies and manufacturers of multifocal IOLs for information about additional published and unpublished studies. Selection criteria: All randomised controlled trials comparing a multifocal IOL of any type with a monofocal IOL as control were included. Both unilateral and bilateral implantation trials were included. Data collection and analysis: Two authors collected data and assessed trial quality. Where possible, we pooled data from the individual studies using a random-effects model, otherwise we tabulated data. MAIN RESULTS: Sixteen completed trials

  6. [Reasons for exchange and explantation of intraocular lenses].

    Science.gov (United States)

    Neuhann, I; Fleischer, F; Neuhann, T

    2012-08-01

    This study was performed to analyse the reasons for explantation/exchange of intraocular lenses (IOL), which had originally been implanted for the correction of aphakia during cataract extraction. All cases with IOL explantation, which had been performed at one institution between 1/2008 and 12/2009 were analysed retrospectively. A total of 105 eyes of 100 patients were analysed. The median time interval between implantation and explantation of the IOL was 5.9 years (min. 0, max. 29.6). The most frequent cause for the intervention was subluxation/dislocation of the implant in 55.2% of cases. This group comprised 21% of cases with subluxation within the capsular bag in pseudoexfoliation syndrome. Other reasons were optical problems/incorrect IOL power (21%), calcification of hydrophilic acrylic IOL (7.6%), corneal decompensation associated with an anterior chamber lens (4.8%), and single cases with varying problems. The reasons for IOL exchange presented in this study are comparable to those of other series in the literature. Explantations due to optical problems may gain weight in the future due to a rise in refractive procedures and demands. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Single-suture scleral fixation of subluxated foldable intraocular lenses.

    Science.gov (United States)

    Yarangumeli, Alper; Alp, Mehmet Numan; Kural, Gulcan

    2012-01-01

    To evaluate the results of single-suture scleral fixation of subluxated foldable intraocular lenses (IOL) in eyes with sufficient residual capsular support. The results of IOL repositioning by single-suture scleral fixation in 6 eyes of 6 patients with IOL subluxation were included. All subluxated IOLs were single-piece hydrophilic acrylic. Subluxation resulted from posterior capsule tears in 3 eyes, zonular dialyses in 2 eyes, and zonular dialysis with a capsulorhexis tear in 1 eye. A similar technique was used in all eyes in which one haptic was externalized through a superior clear corneal incision and tied with a Pair-PAK 10-0 polypropylene suture, and was finally retracted and fixated behind the iris close to the ciliary sulcus at the 12:00 meridian. All patients were followed up for at least 6 months. Best-corrected visual acuities ranged between finger counting and 20/70 (mean logMAR 1.02±0.64) preoperatively, and between 20/100 and 20/20 (mean logMAR 0.22±0.26) at the final postoperative visit. All IOLs remained centered and no significant postoperative complications were encountered except for an IOL tilt which resulted in a considerable oblique astigmatism in one eye. Subluxated foldable IOLs may safely be repositioned and secured with a single scleral fixation suture in selected cases with adequate amount of capsular remnants.

  8. Micro-Raman analysis of glisterings in intraocular lenses

    Science.gov (United States)

    Rusciano, G.; Martinez, A.; Pesce, G.; Zito, G.; Sasso, A.

    2017-06-01

    The phenomenon of inclusions or microvacuoles in intraocular lenses (IOL), often referred to glistenings due to their appearance when visualized in slit-lamp exams, is main cause of decreased visual in people after IOL implantation. For this reason, there is a huge request by the market of new polymers able to reduce, or even eliminate, the formation of such microvacuoles. In such frame, the use of advanced optical techniques, able to provide a deeper insight on the glistering formation, is strongly required. In particular, Raman spectroscopy (RS) is ideally suited for the analysis of polymers, due to its well-know sensitivity to highly polarizable chemical groups, commonly found in the polymer chains backbones. Moreover, the combination of RS with optical microscopy (Raman micro-spectroscopy) paves the way for real, information-rich chemical mapping of polymeric materials (Raman imaging). In this paper, we analyze the formation of microvacuoles in IOLs following a thermal treatment. In particular, we performed a chemical mapping of a single microvacuole, which allowed us to infer on its effective chemical composition. In order to investigate on the reversibility of glistenings formation, this analysis was repeated as function of time after thermal treatment, in different IOL environments. It turns out that this phenomenon is partially reversible, with an almost complete disappearance of microvacuoles in a dry environment.

  9. In vivo chromatic aberration in eyes implanted with intraocular lenses.

    Science.gov (United States)

    Pérez-Merino, Pablo; Dorronsoro, Carlos; Llorente, Lourdes; Durán, Sonia; Jiménez-Alfaro, Ignacio; Marcos, Susana

    2013-04-12

    To measure in vivo and objectively the monochromatic aberrations at different wavelengths, and the chromatic difference of focus between green and infrared wavelengths in eyes implanted with two models of intraocular lenses (IOL). EIGHTEEN EYES PARTICIPATED IN THIS STUDY: nine implanted with Tecnis ZB99 1-Piece acrylic IOL and nine implanted with AcrySof SN60WF IOL. A custom-developed laser ray tracing (LRT) aberrometer was used to measure the optical aberrations, at 532 nm and 785 nm wavelengths. The monochromatic wave aberrations were described using a fifth-order Zernike polynomial expansion. The chromatic difference of focus was estimated as the difference between the equivalent spherical errors corresponding to each wavelength. Wave aberration measurements were highly reproducible. Except for the defocus term, no significant differences in high order aberrations (HOA) were found between wavelengths. The average chromatic difference of focus was 0.46 ± 0.15 diopters (D) in the Tecnis group, and 0.75 ± 0.12 D in the AcrySof group, and the difference was statistically significant (P Chromatic difference of focus in the AcrySof group was not statistically significantly different from the Longitudinal chromatic aberration (LCA) previously reported in a phakic population (0.78 ± 0.16 D). The impact of LCA on retinal image quality (measured in terms of Strehl ratio) was drastically reduced when considering HOA and astigmatism in comparison with a diffraction-limited eye, yielding the differences in retinal image quality between Tecnis and AcrySof IOLs not significant. LRT aberrometry at different wavelengths is a reproducible technique to evaluate the chromatic difference of focus objectively in eyes implanted with IOLs. Replacement of the crystalline lens by the IOL did not increase chromatic difference of focus above that of phakic eyes in any of the groups. The AcrySof group showed chromatic difference of focus values very similar to physiological values in

  10. Aberration-free intraocular lenses - What does this really mean?

    Science.gov (United States)

    Langenbucher, Achim; Schröder, Simon; Cayless, Alan; Eppig, Timo

    2017-09-01

    So-called aberration-free intraocular lenses (IOLs) are well established in modern cataract surgery. Usually, they are designed to perfectly refract a collimated light beam onto the focal point. We show how much aberration can be expected with such an IOL in a convergent light beam such as that found anterior to the human cornea. Additionally, the aberration in a collimated beam is estimated for an IOL that has no aberrations in the convergent beam. The convergent beam is modelled as the pencil of rays corresponding to the spherical wavefront resulting from a typical corneal power of 43m -1 . The IOLs are modelled as infinitely thin phase plates with 20m -1 optical power placed 5mm behind the cornea. Their aberrations are reported in terms of optical path length difference and longitudinal spherical aberration (LSA) of the marginal rays, as well as nominal spherical aberration (SA) calculated based on a Zernike representation of the wavefront-error at the corneal plane within a 6mm aperture. The IOL designed to have no aberrations in a collimated light beam has an optical path length difference of -1.8μm, and LSA of 0.15m -1 in the convergent beam of a typical eye. The corresponding nominal SA is 0.065μm. The IOL designed to have no aberrations in a convergent light beam has an optical path length difference of 1.8μm, and LSA of -0.15m -1 in the collimated beam. An IOL designed to have no aberrations in a collimated light beam will increase the SA of a patient's eye after implantation. Copyright © 2017. Published by Elsevier GmbH.

  11. Refractive accuracy with light-adjustable intraocular lenses.

    Science.gov (United States)

    Villegas, Eloy A; Alcon, Encarna; Rubio, Elena; Marín, José M; Artal, Pablo

    2014-07-01

    To evaluate efficacy, predictability, and stability of refractive treatments using light-adjustable intraocular lenses (IOLs). University Hospital Virgen de la Arrixaca, Murcia, Spain. Prospective nonrandomized clinical trial. Eyes with a light-adjustable IOL (LAL) were treated with spatial intensity profiles to correct refractive errors. The effective changes in refraction in the light-adjustable IOL after every treatment were estimated by subtracting those in the whole eye and the cornea, which were measured with a Hartmann-Shack sensor and a corneal topographer, respectively. The refractive changes in the whole eye and light-adjustable IOL, manifest refraction, and visual acuity were obtained after every light treatment and at the 3-, 6-, and 12-month follow-ups. The study enrolled 53 eyes (49 patients). Each tested light spatial pattern (5 spherical; 3 astigmatic) produced a different refractive change (Plight adjustments induced a maximum change in spherical power of the light-adjustable IOL of between -1.98 diopters (D) and +2.30 D and in astigmatism of up to -2.68 D with axis errors below 9 degrees. Intersubject variability (standard deviation) ranged between 0.10 D and 0.40 D. The 2 required lock-in procedures induced a small myopic shift (range +0.01 to +0.57 D) that depended on previous adjustments. Light-adjustable IOL implantation achieved accurate refractive outcomes (around emmetropia) with good uncorrected distance visual acuity, which remained stable over time. Further refinements in nomograms and in the treatment's protocol would improve the predictability of refractive and visual outcomes with these IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  12. Photochemical generation of antimicrobial Ag-nanoparticles in intraocular lenses

    Science.gov (United States)

    Badur, Thorben; Kim, Hee-Cheol; Hampp, Norbert

    2017-02-01

    The antimicrobial properties of silver (Ag) nanoparticles (NP) have been investigated in depth during the last decades.[1] For cataract treatment minimal invasive surgery has become state-of-the-art. The physicians are still fighting against postoperative inflammations, such as endophthalmitis.[2] We present a novel approach to reduce these postoperative complications by equipping the hydrophilic intraocular lenses (IOL) with a Ag NP depot. As the Ag NP are completely entrapped inside the polymeric IOL no direct contact of the nanoparticles with epithelial cells may occur. Using 1-hydroxybenzotriazole (HOBt) or 7-hydroxycumarine (7HOCum) as photo reduction mediators (PRM) the formation of the Ag NP is accomplished in situ. PRM and Ag nitrate are diffused into the ready made IOL. By means of two-photon-absorption (TPA) photochemistry at λTPA = 532 nm the Ag NP generation is precisely controlled to occur inside the IOL only. At no point NP are directly exposed to the surface.[3] Interesting dependencies between the used PRM and the resulting particle size distribution or the effectiveness of the silver ion reduction inside the polymer matrix are reported. The Ag NP were prepared in the outer area of the IOL not to affect the optical properties of the ophthalmic implant. The amount of Ag ions released was determined and found to be sufficient to effectively reduce the counts of airborne germs. Besides HOBt and 7HOCum we also investigated the photo reductive properties of several other organic reagents, such as benzophenone (BP) and 4-hydroxybenzophenone (4HOBP) for the ability to produce even three-dimensional nanoparticle structures inside a polymer matrix.

  13. Comparison between OPD-scan results and contrast sensitivity of three intraocular lenses: spheric AcrySof SN60AT, aspheric AcrySof SN60WF and multifocal AcrySof Restor lens Estudo comparativo da análise de frente de onda e sensibilidade ao contraste entre as lentes intra-oculares multifocal AcrySof Restor SN60D3, monofocal AcrySof SN60WF asférica e a monofocal SN60AT esférica

    Directory of Open Access Journals (Sweden)

    Celso Takashi Nakano

    2009-08-01

    Full Text Available Purpose: Compare the OPD-scan results and the contrast sensitivity in patients who had implantation of the AcrySof SN60D3 multifocal IOL, the AcrySof SA60AT spheric monofocal IOL and the AcrySof SN60AT aspheric monofocal IOL. Methods: Thirty-two eyes received the multifocal IOL, 32 eyes received the spheric monofocal IOL and 32 eyes received the aspheric monofocal IOL. They were closely paired in age, sex, pre-operative wavefront analysis and contrast sensitivity. All patients was tested with the OPD-scan aberrometer, ETDRS chart at 100% and 9% contrasts and contrast sensitivity. Results: Statistically significant differences were detected more total aberration in SN60AT group (KW = 9.42; p=0.009 when compared to SN60D3 group (p=0.016 and SN60WF group (p=0.0047. The SN60AT group (KW = 16.20; p=0.0003 showed with high spherical aberration values compared to the SN60WF (p=0.00046 and SN60D3 (p=0.0014 group. No significant differences were found between groups in far-distance VA measured using ETDRS at 100% and 9% contrast. The SN60D3 group compared to SN60AT group (p=0.016 had low contrast sensitivity (log units with statistical difference in 6.0 cpd (KW = 7.84; p=0.0199, but no statistical difference between SN60WF and SN60AT group (p=0.91 and SN60WF and SN60D3 group (p=0.051. The SN60D3 group had low contrast sensitivity performed under mesopic conditions (KW = 10.79; p=0,0045 in 6cpd spatial frequency compared to the SN60AT group (p=0.011 and to the SN60WF group (p=0.007 with statistical significant differences. Conclusion: In all analyzed parameters of OPD-scan aberrometry the aspheric and the multifocal IOLs provided less total and spherical aberrations than spheric IOLs. All IOLs provided an excellent high and low contrasts vision, the multifocal IOL was as good as the spheric and aspheric monofocal IOLs.Objetivo: Comparar a sensibilidade ao contraste e análise de "wavefront" com OPD-scan em pacientes submetidos a cirurgia de facoemulsifica

  14. Professor Peter Choyce: an early pioneer of intraocular lenses and corneal/refractive surgery.

    Science.gov (United States)

    Pandey, Suresh K; Apple, David J

    2005-06-01

    Professor Peter Choyce, FRCS, DOMS, MS, was one of the pioneers of intraocular lens implant surgery. He developed an interest in artificial lens implantation following cataract surgery, a procedure that was widely criticized by the ophthalmic establishment in the UK, Europe, North America and other countries. Owing to the opposition to the intraocular lenses, Peter Choyce together with Sir Harold Ridley co-founded the International Intraocular Implant Club in 1966, which was responsible for the gradual acceptance of artificial lens implantation. Peter Choyce developed several models of intraocular lens, but did not patent the majority of them. The Choyce Mark IX, manufactured by Rayner Intraocular Lenses, became the first US Food and Drug Administration-approved intraocular lens in 1981. A review of Peter Choyce's record confirms a significant number of original innovations in the field of anterior segment surgery, including many procedures taken for granted today, but not associated with his name. These include early work on both kerato- and intraocular lens-refractive procedures, keratoprosthesis, pioneering paediatric implant procedures and others. Unfortunately his tenacious adherence to anterior chamber lens technology, while in general clinically sound, caused many to question his influence and hence he remained poorly understood even until after his death. He passed away on 8 August 2001 after a long fight with colon cancer. In this article, we provide evidence and elaborate Peter Choyce's accomplishments, which places him as one of the most innovative ophthalmologist in his surgical field in the twentieth century.

  15. Toric Intraocular Lenses in the Correction of Astigmatism During Cataract Surgery

    DEFF Research Database (Denmark)

    Kessel, Line; Andresen, Jens; Tendal, Britta

    2016-01-01

    TOPIC: We performed a systematic review and meta-analysis to evaluate the benefit and harms associated with implantation of toric intraocular lenses (IOLs) during cataract surgery. Outcomes were postoperative uncorrected distance visual acuity (UCDVA) and distance spectacle independence. Harms were...

  16. Desempenho visual após implante de uma lente intraocular asférica multifocal difrativa Visual performance after implantation of an aspheric multifocal diffractive intraocular lens

    Directory of Open Access Journals (Sweden)

    Leonardo Akaishi

    2010-08-01

    Full Text Available OBJETIVO: Avaliar a acuidade visual a distancia, intermediária e perto após o implante de uma lente intraocular (LIO asférica multifocal difrativa AcrySof® ReSTOR® SN6AD1. MÉTODOS: Estudo prospectivo de 50 pacientes com catarata submetidos à facoemulsificação e implante de LIO AcrySof® ReSTOR®. Foram avaliados acuidade visual sem correção (AVSC, acuidade visual com correção (AVCC para longe, acuidade visual para perto corrigida para longe (AVPC e acuidade visual intermediária corrigida para longe (AVIC. Um questionário de satisfação e fenômenos visuais foi administrado ao final do estudo. RESULTADO: Após três meses de cirurgia, a média das acuidades (logMAR era: AVSC, 0,05 ± 0,07; AVCC, 0,00 ± 0,01; AVPC, 0,00 ± 0,0, e AVIC, 0,15 ± 0,05. A AVCC e AVPC era de 20/25 ou melhor em todos os pacientes, sendo a AVIC J3 ou melhor em 83% dos pacientes. Pacientes relataram excelente desempenho visual nas questões relacionadas a atividades para distância, intermediário, e perto com pouca ou nenhuma dificuldade. Nenhum paciente relatou halos ou 'glare' severos, sendo os mesmos caracterizados entre nenhum a moderado. CONCLUSÃO: A LIO asférica AcrySof® ReSTOR® SN6AD1 mostrou excelentes resultados na visão para longe, perto e intermediário, além de apresentar uma baixa incidência de fenômenos visuais.PURPOSE: To evaluate distance, intermediate, and near vision after aspheric multifocal diffractive AcrySof® ReSTOR® SN6AD1 intraocular lens (IOL implantation. METHODS: Prospective study of 50 patients with cataract that had phacoemulsification and AcrySof® ReSTOR® IOL implantation. Uncorrected distance vision acuity (UDVA, corrected distance visual acuity (CDVA, distance-corrected near visual acuity (DCNVA, and distance-corrected intermediate visual acuity (DCIVA were measured postoperatively. A patient-satisfaction and visual phenomena questionnaire was administered at the end of the study. RESULTS: Three months

  17. A study of patient satisfaction after cataract surgery with implantation of different types of intraocular lenses.

    Science.gov (United States)

    Wei, Ching-Kuo; Wang, Shun-Mu; Lin, Jen-Chieh

    2012-10-29

    The implementation of capitated payment has driven medical institutions through developing balance billing for medical services. By exploring the patients' decision-making factors on different self-pay items, a reference for the pricing and sales strategy for the related products can be formed. The major purposes of this study were to analyze the determinants of preoperative selection and postoperative satisfaction with implantation of different types of intraocular lenses in cataract surgery. This cross-sectional study consisted of 127 patients that were 50 years of age and older, and who had phacoemulsification with intraocular lens implantation in both eyes. Data were collected by using a structured questionnaire. The following parameters were measured: access to medical care, attitude towards receiving medical products at one's own expense, overall patient satisfaction and postoperative visual clarity. The results showed that the patient's gender, educational level and economic status influenced the type of intraocular lens chosen. Patients in the insurance group cared about access to medical care, and patients in the balance billing group cared about product differentiation. ANOVA results showed no statistically significant differences in the overall satisfaction of the patients among the groups with different types of intraocular lenses. Patients that received cataract surgery with implantation of multifocal intraocular lenses had better vision when trying to view smaller objects and when looking at objects under strong light. Manufacturers should increase the number of differences between their products, and health care providers can then recommend the appropriate intraocular lens in accordance with the needs or demands of their patients, and also by keeping in mind the financial constraints of their patients.

  18. A study of patient satisfaction after cataract surgery with implantation of different types of intraocular lenses

    Directory of Open Access Journals (Sweden)

    Wei Ching-Kuo

    2012-10-01

    Full Text Available Abstract Background The implementation of capitated payment has driven medical institutions through developing balance billing for medical services. By exploring the patients’ decision-making factors on different self-pay items, a reference for the pricing and sales strategy for the related products can be formed. The major purposes of this study were to analyze the determinants of preoperative selection and postoperative satisfaction with implantation of different types of intraocular lenses in cataract surgery. Methods This cross-sectional study consisted of 127 patients that were 50 years of age and older, and who had phacoemulsification with intraocular lens implantation in both eyes. Data were collected by using a structured questionnaire. The following parameters were measured: access to medical care, attitude towards receiving medical products at one’s own expense, overall patient satisfaction and postoperative visual clarity. Results The results showed that the patient’s gender, educational level and economic status influenced the type of intraocular lens chosen. Patients in the insurance group cared about access to medical care, and patients in the balance billing group cared about product differentiation. ANOVA results showed no statistically significant differences in the overall satisfaction of the patients among the groups with different types of intraocular lenses. Patients that received cataract surgery with implantation of multifocal intraocular lenses had better vision when trying to view smaller objects and when looking at objects under strong light. Conclusions Manufacturers should increase the number of differences between their products, and health care providers can then recommend the appropriate intraocular lens in accordance with the needs or demands of their patients, and also by keeping in mind the financial constraints of their patients.

  19. In vitro study of antibiotic effect on bacterial adherence to acrylic intraocular lenses.

    Science.gov (United States)

    Gaál, Valéria; Kilár, Ferenc; Acs, Barnabás; Szijjártó, Zsuzsanna; Kocsis, Béla; Kustos, Ildikó

    2005-11-10

    Implantation of artificial intraocular lenses into the eye during ophthalmic surgical procedures ensures an unliving surface on which bacterial pathogens may attach and form biofilms. Despite antibiotic treatment bacteria growing in biofilms might cause inflammation and serious complications. In this study the adhesive ability of 7 Staphylococcus aureus and 11 coagulase-negative Staphylococcus (CNS) strains to the surface of acrylic intraocular lenses had been examined by the ultrasonic method. In untreated cases adhesion of the S. aureus and CNS strains did not differ significantly. We could not demonstrate significant differences between the adhesive ability of the standard strains and the clinical isolates. In this study a single--60 min long--antibiotic (ciprofloxacin and tobramycin) treatment had been applied, that correlate well with the single or intermittant antibiotic prophylaxis of patients. Ciprofloxacin administration was able to reduce significantly the number of attached cells on the surface of acrylic lenses both in the case of S. aureus and CNS strains. Dependence of the effect from concentration could also be demonstrated. Tobramycin treatment was able to inhibit significantly the attachment of S. aureus cells. Despite the debate on antibiotic prophylaxis we presented in our experiments that a single antibiotic administration can decrease the attachment of bacterial cells to the surface of acrylic intraocular lenses, and might be effective in the prevention of postoperative endophthalmitis, that is a rare but serious complication of ophthalmic surgery.

  20. Effect of aspherical and yellow tinted intraocular lens on blue-on-yellow perimetry Efeito das lentes intraoculares asféricas e com pigmentação amarela na campimetria azul-amarelo

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    Rodrigo França de Espíndola

    2012-10-01

    Full Text Available PURPOSE: To investigate the possible effect of aspherical or yellow tinted intraocular lens (IOL on contrast sensitivity and blue-on-yellow perimetry. METHODS: This prospective randomized bilateral double-masked clinical study included 52 patients with visually significant bilateral cataracts divided in two groups; 25 patients (50 eyes received aspherical intraocular lens in one eye and spherical intraocular lens in the fellow eye; and 27 patients (54 eyes received ultraviolet and blue light filter (yellow tinted IOL implantation in one eye and acrylic ultraviolet filter IOL in the fellow eye. The primary outcome measures were contrast sensitivity and blue-on-yellow perimetry values (mean deviation [MD] and pattern standard deviation [PSD] investigated two years after surgery. The results were compared intra-individually. RESULTS: There was a statistically significant between-group (aspherical and spherical intraocular lens difference in contrast sensitivity under photopic conditions at 12 cycles per degree and under mesopic conditions at all spatial frequencies. There were no between-group significant differences (yellow tinted and clear intraocular lens under photopic or mesopic conditions. There was no statistically significant difference between all intraocular lens in MD or PSD. CONCLUSION: Contrast sensitivity was better under mesopic conditions with aspherical intraocular lens. Blue-on-yellow perimetry did not appear to be affected by aspherical or yellow tinted intraocular lens. Further studies with a larger sample should be carried out to confirm or not that hypotheses.OBJETIVO: Investigar a possibilidade de efeitos na sensibilidade ao contraste e nos resultados da campimetria azul-amarelo com implante de uma lente intraocular (LIO asférica ou de pigmentação amarela. MÉTODOS: Trata-se de um estudo prospectivo, randomizado, duplo-mascarado, envolvendo 52 pacientes portadores de catarata senil bilateral, divididos em dois grupos; 25

  1. Anterior capsular support for posterior chamber intraocular lenses following vitreous loss in endocapsular surgery

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    Jacob Pushpa

    1993-01-01

    Full Text Available We used anterior capsular support for posterior chamber intraocular lenses (PC IOLs in fourteen eyes with large posterior capsular ruptures. An endocapsular technique preserved the anterior capsule and facilitated implantation. With a median follow up of 8.5 months, all patients had a visual acuity of 6/9 or better. One lens was lost in the vitreous and one patient had a clinically significant cystoid macular edema. In the event of a posterior capsular rupture we suggest this technique as an alternative to anterior chamber or scleral-fixated lenses

  2. [Impact of an Aspherical Aberration Correcting Monofocal Intraocular Lens on Patient Satisfaction for Daily Life Activities: The Heidelberg Daily Task Evaluation (DATE) Questionnaire].

    Science.gov (United States)

    Kretz, F T A; Son, H; Liebing, S; Tandogan, T; Auffarth, G U

    2015-08-01

    A clinical evaluation of the functional results and its impact on daily activities of an aspherical, aberration correcting intraocular lens (IOL) was undertaken. Twenty-one patients aged from 50 to 83 years underwent cataract surgery with implantation of the aspheric IOL (Tecnis ZCB00, Abbott Medical Optics). They were evaluated 2 to 4 months after surgery for their subjective satisfaction of vision quality and its impact on performance of daily activities as well as functional results and refractive outcome. Patients were asked to fill out a questionnaire - the Heidelberg DATE (DAily Tasks Evaluation) questionnaire. Significant changes from pre- to postoperative results were found in refraction (p ≤ 0.03), with a mean prediction error of + 0.21 ± 0.43 D. UDVA and CDVA improved significantly (p < 0.01), with a postoperative CDVA of 0.0 logMAR or better in 97.1 % of eyes. All patients would recommend the procedure to a relative or a friend and 93.8 % of patients reported to be satisfied with the outcome. The implantation of the aspheric IOL Tecnis ZCB00 after cataract surgery allows the restoration of visual function, providing an optimised optical quality and a high level of patient satisfaction. Georg Thieme Verlag KG Stuttgart · New York.

  3. UV laser ablation of intraocular lenses: SEM and AFM microscopy examination of the biomaterial surface

    International Nuclear Information System (INIS)

    Spyratou, E.; Asproudis, I.; Tsoutsi, D.; Bacharis, C.; Moutsouris, K.; Makropoulou, M.; Serafetinides, A.A.

    2010-01-01

    Several new materials and patterns are studied for the formation and etching of intraocular lenses (IOLs), in order to improve their optical properties, to reduce the diffractive aberrations and to decrease the incidence of posterior capsular opacification. The aim of this study is to investigate the use of UV (λ = 266 nm) laser pulses to ablate the intraocular lenses materials, and thus to provide an alternative to conventional surface shaping techniques for IOLs fabrication. Ablation experiments were conducted using various polymer substrates of hydrophobic acrylic IOLs and PMMA IOLs. We investigated the ablation efficiency and the morphology of the ablated area by imaging the surface modification with atomic force microscopy (AFM) and scanning electron microscopy (SEM). The morphological appearance of IOL samples reveals the effect of a photochemical and photothermal ablation mechanism.

  4. UV laser ablation of intraocular lenses: SEM and AFM microscopy examination of the biomaterial surface

    Energy Technology Data Exchange (ETDEWEB)

    Spyratou, E., E-mail: ellas5@central.ntua.gr [National Technical University of Athens, School of Applied Mathematical and Physical Sciences, Department of Physics, Zografou Campus, Athens, 15780 (Greece); Asproudis, I. [Department of Ophthalmology, University Hospital of Ioannina, Ioannina, 45110 (Greece); Tsoutsi, D. [Department of Chemistry, University of Ioannina, Ioannina, 45110 (Greece); Bacharis, C.; Moutsouris, K.; Makropoulou, M.; Serafetinides, A.A. [National Technical University of Athens, School of Applied Mathematical and Physical Sciences, Department of Physics, Zografou Campus, Athens, 15780 (Greece)

    2010-02-01

    Several new materials and patterns are studied for the formation and etching of intraocular lenses (IOLs), in order to improve their optical properties, to reduce the diffractive aberrations and to decrease the incidence of posterior capsular opacification. The aim of this study is to investigate the use of UV ({lambda} = 266 nm) laser pulses to ablate the intraocular lenses materials, and thus to provide an alternative to conventional surface shaping techniques for IOLs fabrication. Ablation experiments were conducted using various polymer substrates of hydrophobic acrylic IOLs and PMMA IOLs. We investigated the ablation efficiency and the morphology of the ablated area by imaging the surface modification with atomic force microscopy (AFM) and scanning electron microscopy (SEM). The morphological appearance of IOL samples reveals the effect of a photochemical and photothermal ablation mechanism.

  5. Cauterization technique for suture erosion in transscleralfixation of intraocular lenses

    Directory of Open Access Journals (Sweden)

    Xu-Ting Hu

    2013-12-01

    Full Text Available Transscleral suturing is a commonly applied technique to fix intraocular implants in the sulcus. A major problem after transscleral implantation is suture erosion that normally happens in the late post-surgery period and may result in an increased incidence of endophthalmitis. Here we describe an original cauterization method by using a glass rod to melt the exposed suture end without damaging the suture knot in the sclera to avoid suture exposure in sclera-fixed IOL implantation. This is a simple, quick and effective technique that can be performed without conjunctiva incisions and will help to reduce suture erosion related complications.

  6. Effect of gamma radiation on the optical properties of intraocular lenses

    International Nuclear Information System (INIS)

    Naguib, N.I.

    2006-01-01

    The effect of gamma rays in the range of doses up to 150 gray on optical and thermal properties of the intraocular lenses (IOL) made of polymethyl methacrylate (PMMA) was studied. Thermogravimetric analysis (TGA) and differential scanning colorimetry (DSC) have been performed to study the effect of gamma irradiation on the IOL. The results indicate that irradiation up to 150 Gy did not affect greatly the optical and thermal properties of the investigated IOL

  7. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models

    OpenAIRE

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-01

    Background In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. Methods A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3?mm of pupil diameter and...

  8. Intraocular lenses and clinical treatment in paediatric cataract

    Directory of Open Access Journals (Sweden)

    Camila Ribeiro Koch Pena

    2015-06-01

    Full Text Available Pediatric cataract is the most common treatable cause of blindness in children. Prevalence, etiology and morphology vary with the socioeconomic development. The treatment goal is to reduce amblyopia, being difficult management especially in unilateral cases. The decision on aphakia or primary intraocular lens should be individualized as well as correction with contact lens or spectacles. The intraocular lens single-piece hydrophobic acrylic are the most implanted in children and the preferably is in the capsular bag. The Sanders-Retzlaff-Kraff theoretic (SRK/T stressing that is described as more predictable, following Holladay I and SRK II and the recommendation is to under correction +6.0 or +8.0 dioptrias expecting the growth of the eye. The posterior capsule opacity is the most frequent complication and varies with the material choice of the lens. Glaucoma is the most serious postoperative complication and depends on the timing of the surgery, primary lens implantation and time of post surgical follow-up. The adherence to occlusion therapy with patching is critical to the visual prognosis and is determined by the child’s age and laterality of the cataract. There was significant improvement in the surgery and in IOLs, however the final visual prognosis is still not desirable.

  9. Evaluation of Different Power of Near Addition in Two Different Multifocal Intraocular Lenses

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    Ugur Unsal

    2016-01-01

    Full Text Available Purpose. To compare near, intermediate, and distance vision and quality of vision, when refractive rotational multifocal intraocular lenses with 3.0 diopters or diffractive multifocal intraocular lenses with 2.5 diopters near addition are implanted. Methods. 41 eyes of 41 patients in whom rotational +3.0 diopters near addition IOLs were implanted and 30 eyes of 30 patients in whom diffractive +2.5 diopters near addition IOLs were implanted after cataract surgery were reviewed. Uncorrected and corrected distance visual acuity, intermediate visual acuity, near visual acuity, and patient satisfaction were evaluated 6 months later. Results. The corrected and uncorrected distance visual acuity were the same between both groups (p=0.50 and p=0.509, resp.. The uncorrected intermediate and corrected intermediate and near vision acuities were better in the +2.5 near vision added intraocular lens implanted group (p=0.049, p=0.005, and p=0.001, resp. and the uncorrected near vision acuity was better in the +3.0 near vision added intraocular lens implanted group (p=0.001. The patient satisfactions of both groups were similar. Conclusion. The +2.5 diopters near addition could be a better choice in younger patients with more distance and intermediate visual requirements (driving, outdoor activities, whereas the + 3.0 diopters should be considered for patients with more near vision correction (reading.

  10. Do blue-light filtering intraocular lenses affect visual function?

    Science.gov (United States)

    Lavric, Alenka; Pompe, Manca Tekavcic

    2014-11-01

    To study different aspects of visual function, macular changes, and subjective differences between the eye with an ultraviolet (UV) and blue-light filtering intraocular lens (IOL) and the fellow eye with a UV-light filtering IOL. Thirty patients (60 eyes) with senile cataract had both cataracts extracted, and an IOL was implanted at least 2 years before clinical evaluation. In one eye, AcrySof SA60AT (a UV-light filtering IOL) was implanted, whereas in the contralateral eye, AcrySof IQ SN60WF (a blue-light filtering IOL) was implanted. Each patient underwent visual acuity testing, color vision testing (Ishihara and Farnsworth-Munsell 100-hue tests), and contrast sensitivity (CS) testing. The macula was evaluated with optical coherence tomography and with clinical examination. Patients were asked if they noted any difference between the implanted IOLs concerning visual impression. Subjective visual quality was evaluated using the National Eye Institute Visual Functioning Questionnaire. There was a borderline statistically significant difference in the mean best-corrected visual acuity (p = 0.05). As regards color vision, no significant changes in Ishihara and Farnsworth-Munsell 100-hue error scores were detected between both eyes (p = 0.48 and p = 0.59, respectively). Analysis of CS showed no significant difference between the groups at any spatial frequency. There were also no statistically significant differences in central macular thickness and total macular volume between the two IOL groups (p = 0.72 and p = 0.61, respectively). In both IOL groups, three eyes developed an epiretinal membrane, and six eyes developed early signs of age-related macular degeneration. This study showed no significant effects of a blue-light filtering IOL on visual acuity and no influence on color perception and CS. After more than 2 years, there were no significant differences in macular changes between the IOL groups. Clinical evidence of the effect of a blue-light filtering IOL on

  11. Bilateral implantation of +2.5 D multifocal intraocular lens and contralateral implantation of +2.5 D and +3.0 D multifocal intraocular lenses: Clinical outcomes

    NARCIS (Netherlands)

    Nuijts, Rudy M. M. A.; Jonker, Soraya M. R.; Kaufer, Robert A.; Lapid-Gortzak, Ruth; Mendicute, Javier; Martinez, Cristina Peris; Schmickler, Stefanie; Kohnen, Thomas

    2016-01-01

    To assess the clinical visual outcomes of bilateral implantation of Restor +2.5 diopter (D) multifocal intraocular lenses (IOLs) and contralateral implantation of a Restor +2.5 D multifocal IOL in the dominant eye and Restor +3.0 D multifocal IOL in the fellow eye. Multicenter study at 8

  12. Studies on Development of Polymeric Materials Using Gamma Irradiation for Contact and Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Pranshu Chhabra

    2009-01-01

    Full Text Available For the development of materials for contact lenses and intraocular lenses, the selection criteria is based on the (i capacity to absorb and retain water, (ii hydrophilicity and hydrophobicity, (iii refractive index and (iv hardness besides the other essential properties. Various monomers are being studied to develop suitable materials for such applications. Selection of suitable monomers that can be converted into optical materials of desired characteristics is the most essential step. In the present paper, an attempt has been made to develop suitable optical polymers based on 2-hydroxy ethyl methacrylate (HEMA, N-vinyl pyrrolidone (NVP, methyl methacrylate (MMA, methacrylic acid (MAA, and styrene. Compositions were prepared in such a way that polymers of varying hydrophilicity or hydrophobicity could be obtained keeping HEMA as the base (main monomer. For polymerization, gamma irradiation (Co-60 as a source was used. The results of the study showed that: (i an increase in NVP and MAA content brought in an increase in hydrophilicity of polymerized HEMA (pHEMA, while the addition of styrene and MMA decreased hydrophilicity of polymerized HEMA (pHEMA, (ii polymers for contact lenses with water retention capacity as high as >50 wt.% and as low as <10 wt% with varying content of suitable comonomers can be designed, (iii polymeric materials for contact lenses can be made by using radiation processing such as Co-60 and (iv a dose of 40 kGy was found to be ideal for purpose.

  13. A Rapid and Convenient Procedure to Evaluate Optical Performance of Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Frank Schaeffel

    2014-09-01

    Full Text Available A new portable lens scanner was developed and tested for measuring focal lengths and relative contrast transfer of mono- and multifocal intraocular lenses (IOLs. A photograph of a natural scene was imaged in white light through an IOL in a water-filled cuvette, with their +21D base power largely neutralized by a −20D trial lens, using a USB monochrome video camera that could be focused via a laptop-controlled stepping motor from −8.5 to + 8.0D. The output of 10000 ON-OFF antagonistic “receptive fields” measuring the video image with adjustable diameter was continuously recorded by custom written software to quantify focus and relative contrast. Six monofocal and four multifocal IOLs, as well as two radial refractive gradient (RRG lenses were measured. After calibration with trial lenses the optical powers and relative contrast transfer of mono- and multifocal IOLs were readily measured. Refractive power profiles measured in RRG lenses closely matched data obtained from the manufacturer. The lens scanner uses a rapidly operating procedure, is portable and can be used to verify positions of the focal planes of mono- and multifocal IOLs in less than 3 s.

  14. Results of intraocular lens implantation with capsular tension ring in subluxated crystalline or cataractous lenses in children

    OpenAIRE

    Das, Pranab; Ram, Jagat; Brar, Gagandeep Singh; Dogra, Mangat R

    2009-01-01

    Purpose : To evaluate the outcome of intraocular lens (IOL) implantation using capsular tension ring (CTR) in subluxated crystalline or cataractous lenses in children. Setting : Tertiary care setting Materials and Methods : We prospectively studied 18 eyes of 15 children with subluxation of crystalline or cataractous lenses between 90° up to 210° after phacoemulsification, CTR and IOL implantation. Each child was examined for IOL centration, zonular dehiscence and posterior ...

  15. Influence on Visual Quality of Intraoperative Orientation of Asymmetric Intraocular Lenses.

    Science.gov (United States)

    Bonaque-González, Sergio; Ríos, Susana; Amigó, Alfredo; López-Gil, Norberto

    2015-10-01

    To evaluate visual quality when changing the intraocular orientation of the Lentis Mplus LS-312MF nonrotational symmetric +3.00 diopters aspheric multifocal intraocular lens ([IOL] Oculentis GmbH, Berlin, Germany) in normal eyes. An artificial eye was used to measure the in vitro wavefront of the IOL. The corneal topography of 20 healthy patients was obtained. For each eye, a computational analysis simulated the implantation of the IOL. The modulation transfer function (MTF) and an image quality parameter (visually modulated transfer function [VSMTF] metric) were calculated for a 5.0-mm pupil and for three conditions: distance, intermediate, and near vision. The procedure was repeated for each eye after a rotation of the IOL with respect to the cornea from 0° to 360° in 1° steps. Statistical analysis showed significant differences in mean VSMTF values between orientations for distance vision. Optimal orientation of the IOL (different for each eye) showed a mean improvement of 58% ± 19% (range: 20% to 121%) in VSMTF values with respect to the worst possible orientation. For these orientations, intermediate and near vision quality were statistically indistinguishable. The MTFs were different between orientations, showing a mean difference of approximately 5 cycles per degree in the maximum spatial frequencies that can be transferred between the best and the worst orientations for distance vision. The results suggest that implantation of this nonrotational symmetric IOL should improve visual outcomes if it is oriented to coincide with a customized meridian. A simple, practical method is proposed to find an approximation to the angle that an Mplus IOL should be inserted. Copyright 2015, SLACK Incorporated.

  16. Intraocular pressure measurement with the noncontact tonometer through soft contact lenses.

    Science.gov (United States)

    Liu, Yi-Chun; Huang, Jehn-Yu; Wang, I-Jong; Hu, Fung-Rong; Hou, Yu-Chih

    2011-03-01

    To assess the accuracy of measuring intraocular pressure (IOP) through a soft contact lens (SCL) with different refractive powers using a noncontact tonometer (NCT). Thirty-two healthy adult volunteers free of glaucoma or corneal disease participated in this study. IOP was measured in the right eyes without SCLs and with different lens powers, from -3.0 to -12.0 D as measured by NCT. IOP of the left eyes was also measured, as an internal control. Corneal curvature was measured in both eyes using an autokeratometer. Sixteen volunteers wore one brand of SCL (group A) and the other 16 wore a different brand, with 2 different curvatures (groups B and C). Statistical data were analyzed by SPSS using the Wilcoxon signed rank test for comparison of IOP readings and multiple linear regression analysis for the relationship among power of contact lenses, corneal power, and difference in IOP measurements. The difference in mean IOP between eyes without lenses and those with lenses was statistically significant in lens with -6.0 D and below in all 3 groups. The decrease in IOP significantly correlated with the refractive power of contact lenses in all 3 groups. The difference in IOP measurements was influenced by the mean K in group A but not in group B or C. There was no statistically significant difference in the IOP measurements in the left eyes or in the mean K between the right and left eyes. IOP measurement through myopic SCLs by NCT may be inaccurate and tends toward underestimation, especially in high myopic lenses. A strong relationship exists between IOP reduction and myopic lens power.

  17. Calcification of Hydrophilic Acrylic Intraocular Lenses With a Hydrophobic Surface: Laboratory Analysis of 6 Cases.

    Science.gov (United States)

    Gartaganis, Sotirios P; Prahs, Philipp; Lazari, Eftichia D; Gartaganis, Panos S; Helbig, Horst; Koutsoukos, Petros G

    2016-08-01

    To investigate the nature and characteristic features of deposits causing opacification of intraocular lenses (IOLs) based on the examination of clinical findings using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) analysis. Retrospective, observational case series. This is a multicenter study of 6 hydrophilic acrylic IOLs (Lentis LS-502-1; Oculentis GmbH, Berlin, Germany) with a hydrophobic surface that were explanted from 5 patients because of opacification. Three patients had an uncomplicated phacoemulsification. One patient underwent combined phacoemulsification and pars plana vitrectomy for retinal detachment and later silicone oil endotamponade owing to redetachment. The last patient had a pars plana vitrectomy and silicone oil instillation combined with phacoemulsification for tractive retinal detachment and diabetic retinopathy. The explanted lenses were submitted to our laboratory and were examined by SEM and EDX in order to identify the morphologic features and the composition of the deposits. SEM and EDX analyses confirmed the presence of calcific deposits in the interior of the opacified hydrophilic IOLs, with a pattern showing the formation of lumps on the surface. The lumps were due to subsurface formation of calcium phosphate crystalline deposits. The crystallite clusters seemed to diffuse from the IOL interior to the surface. We demonstrated the calcification pattern of the hydrophilic IOL (Lentis LS-502-1) with a hydrophobic surface. Although hydrophilic acrylic lenses have a hydrophobic surface, the development of calcification is a possible threat initiating from the hydrophilic subsurface of the IOLs. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. [Effect of intraocular pressure measurement through therapeutic soft contact lenses by noncontact tonometer].

    Science.gov (United States)

    Sugimoto-Takeuchi, R; Yamamoto, R; Kuwayama, Y; Kinoshita, S

    1991-09-01

    The measurement of intraocular pressure (IOP) was compared with and without soft contact lenses by a non-contact tonometer. The soft contact lenses examined were Plano-T and Plano-B4 therapeutic contact lenses and Breath-O refractive lens. Twenty-nine eyes of 18 patients with an IOP ranging from 9 to 48mmHg were studied. The measurements of IOP were 19.7 +/- 8.6mmHg with Plano-T and 18.9 +/- 9.2mmHg with Plano-B4. Both numbers were not statistically different, when compared with controls (19.3 +/- 9.8mmHg without lens). There was, however, a significant difference significant difference with (44.7 +/- 10.7mmHg) and without the Breath-O (p less than 0.01). The results suggest that accurate IOP measurements can be obtained through therapeutic soft contact lens by a non-contact tonometer.

  19. The measurement of intraocular pressure over positive soft contact lenses by rebound tonometry.

    Science.gov (United States)

    Zeri, Fabrizio; De Cusatis, Mario; Lupelli, Luigi; Swann, Peter Graham

    2016-01-01

    To investigate if the accuracy of intraocular pressure (IOP) measurements using rebound tonometry over disposable hydrogel (etafilcon A) contact lenses (CL) is affected by the positive power of the CLs. The experimental group comprised 26 subjects, (8 male, 18 female). IOP measurements were undertaken on the subjects' right eyes in random order using a Rebound Tonometer (ICare). The CLs had powers of +2.00D and +6.00D. Measurements were taken over each contact lens and also before and after the CLs had been worn. The IOP measure obtained with both CLs was significantly lower compared to the value without CLs (t test; p<0.001) but no significant difference was found between the two powers of CLs. Rebound tonometry over positive hydrogel CLs leads to a certain degree of IOP underestimation. This result did not change for the two positive lenses used in the experiment, despite their large difference in power and therefore in lens thickness. Optometrists should bear this in mind when measuring IOP with the rebound tonometer over plus power contact lenses. Copyright © 2016 The Authors. Published by Elsevier Espana.. All rights reserved.

  20. Management of subluxated capsular bag-fixated intraocular lenses using a capsular anchor.

    Science.gov (United States)

    Ton, Yokrat; Naftali, Modi; Gortzak, Ruth Lapid; Assia, Ehud I

    2016-05-01

    We describe the use of the capsular anchor (AssiAnchor) to manage a subluxated intraocular lens (IOL) in the capsular bag. The anchor comprises 2 prongs that hold the anterior lens capsule and a central rod that is sutured to the scleral wall, enabling centration of the IOL-capsular bag complex. Six pseudophakic patients presenting with subluxated posterior chamber IOLs in the capsular bag were operated on using the device. The anchor was used successfully in all cases, although in 2 cases only 1 prong was placed under the capsulorhexis edge. In 1 eye, 2 anchors were used 1 month apart following repeated traumatic zonular injury. The capsular bag holding the IOL remained centered and stable throughout the follow-up period. The anchoring device, which was originally designed to preserve the lens capsule and stabilize subluxated crystalline lenses, can also be used to treat subluxation of a capsular bag-fixated IOL. Dr. Assia is the inventor of the AssiAnchor, has a licensed patent of the anchor, and is consultant to Hanita Lenses. Dr. Lapid-Gortzak is a consultant to and speaker for Alcon Surgical, Inc., Hanita Lenses, Orca Surgical, and Sanoculis Ltd.; a speaker for Santen; and a consultant to Icon. Drs. Ton and Naftali have no financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  1. Surface modification of polymethyl methacrylate intraocular lenses by plasma for improvement of antithrombogenicity and transmittance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lihua; Wu Di; Chen Yashao; Wang Xiaoli; Zhao Guowei; Wan Haiyan [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, School of Chemistry and Materials Science, Chang' an South Road 199, Xi' an 710062 (China); Huang Changzheng [Able Eye Device Co. Ltd, Zhengzhou 450008 (China)

    2009-05-15

    To improve antithrombogenicity and reduce ultraviolet transmittance, polymethyl methacrylate intraocular lenses (PMMA IOLs) were pretreated with Ar plasma and combined with heparin (Hp), with polyglycol (PEG) and with both Hp and PEG in a plasma atmosphere. The resulting modified PMMA IOLs denoted as PEG-PMMA, Hp-PMMA and Hp-PEG-PMMA were characterized by attenuated total reflectance Fourier transfer infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis), contact angle (CA) and platelet adhesion experiments. The results indicated that Hp and PEG had been successfully immobilized onto the surfaces of PMMA IOLs. Antithrombogenicity was improved remarkably and ultraviolet transmittance was reduced as well.

  2. Opacification of hydrophilic intraocular lenses after Descemet stripping automated endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Morgan-Warren PJ

    2015-02-01

    Full Text Available Peter J Morgan-Warren, Walter Andreatta, Amit K Patel Department of Ophthalmology, Solihull Hospital, Heart of England NHS Foundation Trust, Birmingham, UK Purpose: Opacification of hydrophilic acrylic intraocular lenses (IOLs is an emerging complication following Descemet stripping automated endothelial keratoplasty (DSAEK. We report six cases and review the current literature.Methods: In this retrospective, noncomparative, observational case series, patients with IOL opacification after previous DSAEK surgery were identified from corneal clinic records. Case notes were reviewed for demographic details, indication for DSAEK, IOL model, incidence of rebubbling, and postoperative course.Results: Six patients developed IOL opacification after DSAEK. All patients had Fuchs’ endothelial dystrophy and had previously received hydrophilic acrylic IOL models. Central anterior IOL opacification was noted in all six cases. Five cases (83% had required rebubbling due to dislocated graft tissue, and one had an early postoperative intraocular pressure (IOP rise. Five cases (83% were managed conservatively, and one case with a failed graft underwent redo DSAEK and IOL exchange.Conclusion: Repeated exposure to intracameral air, raised IOP, and other patient influences may be major etiological factors for IOL opacification after DSAEK. We advise avoiding hydrophilic acrylic IOL models in patients who may require future endothelial keratoplasty. Keywords: IOL, DSAEK, lamellar keratoplasty, endothelial corneal transplantation

  3. Effect of cefuroxime and moxifloxacin on Staphylococcus epidermidis adherence to intraocular lenses.

    Science.gov (United States)

    Karadağ, Serhat; Ozkan, Berna; Karabaş, V Levent; Alintaş, Ozgül; Yumuk, Zeki; Cağlar, Yusuf

    2009-12-01

    To investigate and compare the effect of cefuroxime and moxifloxacin on adhesion of Staphylococcus epidermidis to intraocular lenses (IOLs). Experimental study. The 3-pieced hydrophobic acrylic lenses were contaminated with S. epidermidis (American Type Culture Collection 35983) solutions containing 108 colony-forming units. IOLs were inoculated into test tubes containing tryptic soy broth after being held in antibiotic solutions for 15 minutes. Sonication and vortex procedures were performed in order to remove all the remaining bacteria. From each tube 10 microL and 100 microL was taken and inoculated into sheep blood agar. The colonies were counted overnight. The statistical analyses were made using one-way ANOVA, Turkey Honestly Significant Differences test (HSD) and independent t tests, and a p value less than 0.05 was considered statistically significant. Overall, the mean numbers of colony-forming units on the lenses that were held in control, cefuroxime, moxifloxacin 0.5 mg/0.1 mL and moxifloxacin 0.1 mg/0.1 mL solutions were 1398 (SE 10.01 x 10(3)), 29.9 (SE 1.16 x 10(3)), 0.23 (SD 0.04 x 10(3)), and 0.41 (SD 0.05 x 10(3)), respectively. The evaluation using one-way ANOVA and Turkey HSD tests revealed significant statistical differences among the groups (p = 0.000). The evaluation using independent t tests revealed significant statistical differences between the 2 moxifloxacin groups (p < 0.05). Our results suggest that moxifloxacin and cefuroxime significantly inhibit bacterial adherence to IOLs. The effect of moxifloxacin on inhibition of bacterial adherence was significantly greater than that of cefuroxime. For this reason moxifloxacin might be considered as a better prophylactic agent.

  4. [In Vitro Evaluation of the Optical Quality of Segmental Refractive Multifocal Intraocular Lenses].

    Science.gov (United States)

    Yildirim, Timur Mert; Auffarth, Gerd Uwe; Tandogan, Tamer; Liebing, Stephanie; Labuz, Grzegorz; Choi, Chul Young; Khoramnia, Ramin

    2017-11-08

    In customised patient care, it is important to know the optical quality of different intraocular lenses (IOL). In this study, the optical quality of three segmental intraocular lenses were compared. The LENTIS Comfort LS-313 MF15, LENTIS Mplus X LS-313 MF30 and LENTIS High Add IOL LS-313 MF80 (Oculentis, Berlin, Germany) with a far power of + 21 D were analysed at the optical bench OptiSpheric IOL PRO (Trioptics GmbH, Wedel, Germany). The lenses have almost the same optical design but differ in the power of the near segment. The MF15 has a + 1.5 D addition to improve vision in intermediate distances, the MF30 has a near addition of + 3 D and the MF80 has a near addition of + 8 D. The modulation transfer function area (MTFa) and the Strehl ratio were examined for apertures of 3 mm (photopic) and 4.5 mm (mesopic). The MTFa values for the far focus are 33.34/30.80/51.53 (MF15/MF30/MF80) with an aperture of 3 mm and 25.38/22.52/43.15 for 4.5 mm. The MTFa values for the intermediate focus are 29.85/16.21/6.25 for a 3 mm aperture and 23.92/8.05/3.08 for 4.5 mm. The MTFa values for the near focus are 9.75/21.49/33.12 for an aperture of 3 mm and 4.95/22.70/31.68 for 4.5 mm. The Strehl ratio of the far focus is 0.34/0.30/0.52 for an aperture of 3 mm and 0.24/0.22/0.43 for 4.5 mm. For the intermediate focus, the Strehl ratio is 0.30/0.17/0.07 for an aperture of 3 mm and 0.24/0.08/0.03 for 4.5 mm. The Strehl ratio of the near focus is 0.10/0.22/0.33 for an aperture of 3 mm and 0.05/0.23/0.32 for 4.5 mm. We confirmed that the addition influences the optical quality of segmental bifocal intraocular lenses. For the far focus, the results of the MF15 and MF30 are similar. In intermediate distances, the MF15 achieves the best results. For near distances, the MF30 achieves better optical values than the MF15. The lens MF80, which has been designed for patients with maculopathies, achieves good results for far and near distances. Georg

  5. Light transmission through intraocular lenses with or without yellow chromophore (blue light filter) and its potential influence on functional vision in everyday environmental conditions.

    Science.gov (United States)

    Owczarek, Grzegorz; Gralewicz, Grzegorz; Skuza, Natalia; Jurowski, Piotr

    2016-01-01

    In this research the factors used to evaluate the light transmission through two types of acrylic hydrophobic intraocular lenses, one that contained yellow chromophore that blocks blue light transmission and the other which did not contain that filter, were defined according to various light condition, e.g., daylight and at night. The potential influence of light transmission trough intraocular lenses with or without yellow chromophore on functional vision in everyday environmental conditions was analysed.

  6. Biofilm Formation by Staphylococcus epidermidis on Foldable and Rigid Intraocular Lenses.

    Science.gov (United States)

    Fazly Bazzaz, Bibi Sedigheh; Jalalzadeh, Monireh; Sanati, Maryam; Zarei-Ghanavati, Syamak; Khameneh, Bahman

    2014-05-01

    Biofilm formation of Staphylococcus epidermidis is a major etiological factor of inducing device-related infections. The ability of biofilm formation by the S. epidermidis was assessed in vitro on two brands of foldable (hydrophilic) and two brands of rigid (hydrophobic) intraocular lens materials in order to investigate the role of lens material in postoperative endophthalmitis. To ensure reproducibility of biofilm formation on intraocular lenses, two strains of S. epidermidis and three quantification methods were performed. The S. epidermidis strains, DSMZ3270 (biofilm-producer) and ATCC12228 (non-biofilm-producer) were applied. Organisms were cultivated on disks of different brands of foldable hydrophilic Intra Ocular Lens (IOL) made of acrylic (Didar, Iran; (A) and Omni, India; (B)), and rigid hydrophobic IOL made of polymethyl methacrylate (PMMA; Didar, Iran; (C) and Hexavision, France; (D)). Biofilms were stained with crystal violet (CV) dye, which is an index of biofilm formation. The bacterial population was counted after biofilm homogenization. Scanning electron microscopy (SEM) was performed to examine the extent of biofilm formation. Adherence of DSMZ3270 strain on both types of foldable and rigid IOLs, was significantly more than ATCC12228 (P brands of foldable and PMMA IOLs. According to statistical analyses the incubation time influenced the biofilm formation on both types of IOLs which meant that by increasing incubation time, the biofilm formation increased. According to the SEM pictures, biofilm seems to be lysed at 72 hours. These data demonstrated that the attachment of bacteria to hydrophilic acrylic IOLs was more than hydrophobic PMMA ones independent of the brand. According to these results the bacterial strain might have more hydrophilic properties. Augmenting the biomass of biofilm by passing of time demonstrated the key role of time in biofilm formation on the IOL surfaces. The differences between IOL brands in the biofilm formation

  7. A comparison of visual outcomes in three different types of monofocal intraocular lenses.

    Science.gov (United States)

    Shetty, Vijay; Haldipurkar, Suhas S; Gore, Rujuta; Dhamankar, Rita; Paik, Anirban; Setia, Maninder Singh

    2015-01-01

    To compare the visual outcomes (distance and near) in patients opting for three different types of monofocal intraocular lens (IOL) (Matrix Aurium, AcrySof single piece, and AcrySof IQ lens). The present study is a cross-sectional analysis of secondary clinical data collected from 153 eyes (52 eyes in Matrix Aurium, 48 in AcrySof single piece, and 53 in AcrySof IQ group) undergoing cataract surgery (2011-2012). We compared near vision, distance vision, distance corrected near vision in these three types of lenses on day 15 (±3) post-surgery. About 69% of the eyes in the Matrix Aurium group had good uncorrected distance vision post-surgery; the proportion was 48% and 57% in the AcrySof single piece and AcrySof IQ group (P=0.09). The proportion of eyes with good distance corrected near vision were 38%, 33%, and 15% in the Matrix Aurium, AcrySof single piece, and AcrySof IQ groups respectively (P=0.02). Similarly, The proportion with good "both near and distance vision" were 38%, 33%, and 15% in the Matrix Aurium, AcrySof single piece, and AcrySof IQ groups respectively (P=0.02). It was only the Matrix Aurium group which had significantly better both "distance and near vision" compared with the AcrySof IQ group (odds ratio: 5.87, 95% confidence intervals: 1.68 to 20.56). Matrix Aurium monofocal lenses may be a good option for those patients who desire to have a good near as well as distance vision post-surgery.

  8. In vivo subjective and objective longitudinal chromatic aberration after bilateral implantation of the same design of hydrophobic and hydrophilic intraocular lenses.

    Science.gov (United States)

    Vinas, Maria; Dorronsoro, Carlos; Garzón, Nuria; Poyales, Francisco; Marcos, Susana

    2015-10-01

    To measure the longitudinal chromatic aberration in vivo using psychophysical and wavefront-sensing methods in patients with bilateral implantation of monofocal intraocular lenses (IOLs) of similar aspheric design but different materials (hydrophobic Podeye and hydrophilic Poday). Instituto de Optica, Consejo Superior de Investigaciones Cientificas, Madrid, Spain. Prospective observational study. Measurements were performed with the use of psychophysical (480 to 700 nm) and wavefront-sensing (480 to 950 nm) methods using a custom-developed adaptive optics system. Chromatic difference-of-focus curves were obtained from best-focus data at each wavelength, and the longitudinal chromatic aberration was obtained from the slope of linear regressions to those curves. The longitudinal chromatic aberration from psychophysical measurements was 1.37 diopters (D) ± 0.08 (SD) (hydrophobic) and 1.21 ± 0.08 D (hydrophilic). From wavefront-sensing, the longitudinal chromatic aberration was 0.88 ± 0.07 D and 0.73 ± 0.09 D, respectively. At 480 to 950 nm, the longitudinal chromatic aberration was 1.27 ± 0.09 D (hydrophobic) and 1.02 ± 0.13 D (hydrophilic). The longitudinal chromatic aberration was consistently higher in eyes with the hydrophobic IOL than in eyes with the hydrophilic IOL (a difference of 0.16 D and 0.15 D, respectively). Similar to findings in young phakic eyes, the longitudinal chromatic aberration from the psychophysical method was consistently higher than from wavefront-sensing, by 0.48 D (35.41%) for the hydrophobic IOL and 0.48 D (39.43%) for the hydrophilic IOL. Longitudinal chromatic aberrations were smaller with hydrophilic IOLs than with hydrophobic IOLs of the same design. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  9. Instrumental studies on silicone oil adsorption to the surface of intraocular lenses

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chun Ho [Lab. of Tissue Engineering, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Joo, Choun-Ki [Department of Ophthalmology and Visual Science, Medical College of Catholic University, Seoul 137-701 (Korea, Republic of); Chun, Heung Jae, E-mail: chunhj@catholic.ac.kr [Institute of Cell and Tissue Engineering, Medical College of Catholic University, Seoul 137-701 (Korea, Republic of); Yoo, Bok Ryul [Organosilicone Chemistry Laboratory, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of); Noh, Dong Il; Shim, Young Bock [Research Institute of Biomedical Engineering, Korea Bone Bank Co. Ltd., Seoul 153-782 (Korea, Republic of)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer It was found that PHEMA and Acrysof IOLs possess silicone oil repellant ability. Black-Right-Pointing-Pointer The residual silicone oil was detected on the surfaces of PMMA and silicone IOLs. Black-Right-Pointing-Pointer XPS studies showed that silicone oil coverage of PMMA lenses was 12%. Black-Right-Pointing-Pointer Silicone oil covered the entire surface of the silicone IOLs. - Abstract: The purpose of this study was to examine the degree of adherence of silicone oil to various intraocular lenses (IOLs) through comparison of the physico-chemical properties of the oil and IOLs. Four kinds of IOLs comprising various biomaterials were examined: PMMA (720A Trade-Mark-Sign ), PHEMA (IOGEL 1103 Trade-Mark-Sign ), Acrysof (MA60BM Trade-Mark-Sign ), and silicone (SI30NB Trade-Mark-Sign ). Each lens was immersed in silicone oil or carboxylated silicone (CS-PDMS) oil for 72 h. For determination of the changes in chemical and elemental compositions on the surfaces of IOLs caused by the contact with silicone oil, IOLs were washed and rinsed with n-pentane to remove as much of the adsorbed silicone oil as possible, then subjected to Fourier transform infrared spectroscopic (FTIR) and X-ray photoelectron spectroscopic (XPS) analyses. The results of FTIR studies strongly indicate that washing with n-pentane completely removed the adhered silicone oil on the surfaces of PHEMA and Acrysof IOLs, whereas the residual silicone oil was detected on the surfaces of PMMA and silicone IOLs. XPS studies showed that silicone oil coverage of PMMA lenses was 12%, even after washing with n-pentane. In the case of silicone IOLs, the relative O1s peak area of carboxyl group in the residual CS-PDMS oil was found to be {approx}2.7%. Considering that 2.8% carboxyl group-substituted silicone oil was used in the present study, CS-PDMS oil covered the entire surface of the silicone IOLs.

  10. Comparison of visual function and patient satisfaction with AcrySof ReSTORSN6AD1 multifocal intraocular compared to monofocal intraocular lenses 5

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    Aisa S Alchinova

    2016-12-01

    Full Text Available Aim. To compare visual function and satisfaction in patients after implantation of AcrySof ReSTOR SN6AD1 multifocal intraocular lens (IOL, AcrySof SA60AТ spherical monofocal IOL, or Akreos АО aspheric monofocal IOL during cataract surgery. Materials. Overall, 34 patients received SN6AD1 multifocal (group 1, 48 eyes, 19 patients received Akreos АО monofocal aspheric (group 2, 30 eyes, and 13 patients received AcrySof SA60AТ monofocal spherical (group 3, 18 eyes IOL. Patients with multifocal IOL were closely matched for age, sex, and ocular findings with patients who had monofocal IOL implantation. Six months postoperatively, uncorrected/corrected distance visual acuity (UDVA/CDVA, uncorrected intermediate (60 cm and near (35 cm visual acuity (UNVA, defocus curve, contrast sensitivity, and a quality-of-life questionnaire were evaluated. Furthermore, independence from glasses and presence of optical phenomena were assessed. Results. Patients in group 2 had statistically significant increase in UDVA than that in group 1 (p = 0.037. There was no significant difference in the mean uncorrected intermediate and best corrected distance visual acuities between the groups. UNVA was better in group 1 than that in groups 2 and 3 (p < 0.0001. Photopic contrast sensitivity for high spatial frequencies was better in groups 2 and 3. Glare was reported in 5.9% of patients in group 1. Halos occurred in 32.4% of patients in group 1. No one reported undesirable visual symptoms in groups 2 and 3. Conclusion. Multifocal IOLs provided higher spectacle independence and satisfactory functional vision over a broad range of distances but were associated with increased subjective visual symptoms and reduced photopic contrast sensitivity for high spatial frequencies and distance visual quality compared with monofocal IOLs.

  11. Gas chromatographic determination with electron capture detection of residual ethylene oxide in intraocular lenses

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, H.; Nakamura, A.; Tsuji, K.

    1988-01-01

    A sensitive method is described to determine trace quantities of ethylene oxide (EO) in EO-sterilized intraocular lenses (IOLs). An IOL is dipped in ethanol containing 0.25 ppm propylene oxide (PO) in a 4 mL vial, 2 drops of freshly distilled hydrobromic acid is added through a septum, and the mixture is warmed at 50/sup 0/C for 24 h. It is then neutralized by vigorous shaking with sodium bicarbonate, dehydrated with anhydrous sodium sulfate, and filtered. The filtrate is injected into a gas chromatograph with electron-capture detection, and the peak height ratio of ethylene bromohydrin/propylene bromohydrin is measured. EO residue is calculated from the calibration curve obtained through a similar procedure with the standard EO/PO solutions. The limit of determination is 0.04 ..mu..g/lens (ca 2.0 ppm). When EO residue levels were determined for IOLs sampled at 3 different aeration periods after stabilization, the authors found that 9 days of aeration was necessary to meet the US Food and Drug Administration proposed limit for EO residue in IOLs.

  12. Intraocular pressure readings obtained through soft contact lenses using four types of tonometer.

    Science.gov (United States)

    Takenaka, Joji; Kunihara, Eriko; Rimayanti, Ulfah; Tanaka, Junko; Kaneko, Makoto; Kiuchi, Yoshiaki

    2015-01-01

    To compare the reliability and accuracy of intraocular pressure (IOP) measured while wearing soft contact lenses (SCLs) using a non-contact tonometer (NCT), Goldmann applanation tonometer (GAT), iCare rebound tonometer (RBT) and the Tono-Pen XL. Twenty-six healthy subjects were examined. The IOP was measured using NCT, GAT, RBT, and the Tono-Pen XL, while the subjects wore SCLs -5.00 D, -0.50 D and +5.00 D. Bland-Altman plots and a regression analysis were used to compare the IOPs obtained with those instruments and the IOPs of the naked eyes measured using GAT (the standard IOPs in this study). The IOPs obtained by the Tono-Pen XL while the subjects were wearing -5.00 D, -0.50 D, and +5.00 D SCLs were significantly higher than those of the naked eyes obtained using GAT. RBT showed that the IOPs were similar to the GAT standard IOPs under all conditions. The IOPs measured with NCT and GAT while the subjects were wearing -5.00 D and -0.50 D SCLs were similar to the GAT standard IOPs. The IOPs obtained with RBT and NCT while the subjects were wearing -5.00 D and -0.50 D SCLs exhibited a good correlation with the standard IOPs. The NCT and RBT are best when measuring IOP through hydrogel SCLs.

  13. Comparison of clinical performance between trifocal and bifocal intraocular lenses: A meta-analysis.

    Science.gov (United States)

    Xu, Zequan; Cao, Danmin; Chen, Xu; Wu, Song; Wang, Xin; Wu, Qiang

    2017-01-01

    To compare the clinical performance between trifocal and bifocal intraocular lenses in bilateral cataract and/or refractive lens exchange (RLE) surgery. A comprehensive literature search of PubMed, EMBASE, Cochrane Controlled Trials Register and Web of Science was performed through October 2016 to identify randomized, controlled trials (RCTs) and comparative cohort studies. The primary outcomes were uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), defocus curve, spectacle independence, patient satisfaction and contrast sensitivity. The secondary outcomes were residual sphere, spherical equivalent (SE), cylinder and complications. Six RCTs and 2 cohort studies including 568 eyes (278 in the trifocal group and 290 in the bifocal group) were identified. There was a statically significant difference between the two groups in UDVA (WMD: -0.03, 95% CI: -0.05 to -0.01, P = 0.005), but the difference (0.03 log MAR) is not clinically significant. Intermediate visual acuity was better in the trifocal IOL group judging from UIVA and defocus curves. There was a statically significant difference between the two groups in residual cylinder (WMD: 0.11, 95% CI: 0.02 to 0.20, P = 0.02), and subgroup AT Lisa tri 839MP trifocal also showed significant better UNVA than bifocal IOLs (WMD: -0.13, 95% CI: -0.17 to -0.08, Pbetter uncorrected near visual acuity than bifocal IOLs. However, more evidence is needed to compare their spectacle independence, higher satisfaction rate, and photic phenomena.

  14. Evaluation of Optical Quality: Ocular Scattering and Aberrations in Eyes Implanted with Diffractive Multifocal or Monofocal Intraocular Lenses.

    Science.gov (United States)

    Liao, Xuan; Lin, Jia; Tian, Jing; Wen, BaiWei; Tan, QingQing; Lan, ChangJun

    2018-06-01

    To compare objective optical quality, ocular scattering and aberrations of eyes implanted with an aspheric monofocal intraocular lens (IOL) or an aspheric apodized diffractive multifocal IOL three months after surgery. Prospective consecutive nonrandomized comparative cohort study. A total of 80 eyes from 57 cataract patients were bilaterally or unilaterally implanted with monofocal (AcrySof IQ SN60WF) or multifocal (AcrySof IQ ReSTOR SN6AD1) IOLs. Respectively, 40 eyes of 27 patients were implanted with monofocal IOLs, and 40 eyes of 30 patients were implanted with multifocal IOLs. Ocular high-order aberration (HOA) values were obtained using Hartmann-Shack aberrometer; objective scatter index (OSI), modulation transfer function (MTF) cutoff, Strehl ratio (SR), and contrast visual acuity OV at 100%, 20%, and 9% were measured using Objective Quality Analysis System II (OQAS II). Ocular aberrations performed similar in both groups (p > 0.05). However, significantly higher values of OSI and lower values of MTF cutoff, SR and OV were found in the SN6AD1 group (p < 0.05). Both ocular scattering and wave-front aberrations play essential role in retinal image quality, which may be overestimated when only aberrations were taken into account. Combining the effect of ocular scattering with HOA will result in a more accurate assessment of the visual and optical quality.

  15. The effects of the modulus of the lens material on intraocular pressure measurement through soft contact lenses.

    Science.gov (United States)

    Boyraz, S; Güngör, I

    2013-09-01

    To investigate the effects of the modulus of the lens material on the intraocular pressure measurement using the Tono-Pen XL applanation tonometer through soft contact lenses. Thirty eyes of 15 patients with myopia were evaluated. Intraocular pressure (IOP) measurements were performed using Tono-Pen XL directly over cornea, and subsequently through three soft contact lenses made up of different lens materials. All were -3.00 diopter soft contact lenses: lotrafilcon A with a low water content (24%) and high modulus (1.4 MPa) (CL-I), balafilcon A with a moderate water content (36%) and moderate modulus (1.1 MPa) (CL-II), and vifilcon A with a moderate water content (55%) and low modulus (0.79 MPa) (CL-III). IOP measurements through contact lenses were compared with each other, and with direct corneal measurements. The mean age of the patients (11 males and 4 females) was 26.86±5.62 years. All measurements obtained through CLs were significantly higher than the direct corneal measurements. The measurements through CLs differed by 4.61±0.54 mmHg (P=0,001), 2.9±0.46 mmHg (P=0.001), and 1.94±0.51 mmHg (P=0,003) for CL-I, CL-II and CL-III, respectively. In the paired comparisons of measurements through CLs, all comparisons were significant except the comparison of measurements through CL-II and CL-III (P=0.128). IOP measurements through silicone-hydrogel contact lenses with a high modulus and low water content were higher compared to the other contact lenses. While measuring IOP through CLs, the clinicians should consider the effect of the lens material and the features of the device used.

  16. Aderência in vitro do Staphylococcus epidermidis e da Pseudomonas alcaligenes em lentes intra-oculares In vitro adherence of Staphylococcus epidermidis and Pseudomonas alcaligenes to intraocular lenses

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    Patrícia Ioschpe Gus

    2006-06-01

    Full Text Available OBJETIVO: Quantificar e comparar a aderência in vitro das bactérias Staphylococcus epidermidis e Pseudomonas alcaligenes em diferentes tipos de lentes intra-oculares (LIOs. MÉTODOS: Quatorze lentes intra-oculares foram usadas no experimento. Quatro de polimetilmetacrilato (PMMA, quatro de silicone, quatro de hidrogel e duas de acrílico. Oito lentes intra-oculares foram colocadas em oito tubos de ensaio contendo 4 ml de suspensão de Pseudomonas alcaligenes, e seis lentes intra-oculares foram colocadas em seis tubos de ensaio contendo 4 ml de suspensão de Staphylococcus epidermidis. A concentração do caldo utilizada para o teste de aderência foi de 10(8 unidades formadoras de colônias por mililitro (CFU/mL que corresponde a 0,5 na escala de McFarland. As lentes foram incubadas a 37° por duas horas. Após, foram removidas dos caldos e enxaguadas em água destilada estéril por duas vezes. As lentes foram cultivadas em placas de ágar-sangue a 35-37° e evaliadas a cada 24h por um período de 72h. Nas amostras que tiveram crescimento bacteriano, foram contadas as colônias utilizando os métodos convencionais de laboratório. Todos os ensaios foram executados em duplicata. RESULTADOS: A aderência do Staphylococcus epidermidis nas lentes de PMMA foi menor se comparada com as de silicone e de hidrogel. A aderência daPseudomonas alcaligenes nas lentes de hidrogel foi menor se comparada com as de silicone, PMMA e acrílico. CONCLUSÃO: Os resultados sugerem que a aderência do Staphylococcus epidermidis e da Pseudomonas alcaligenes nas lentes intra-oculares é influenciada pelo tipo de material da lente e pela espécie do microorganismo. A aderência bacteriana pode ter papel importante na patogenicidade da endoftalmite pós-cirurgia de catarata.PURPOSE: To quantify and compare the in vitro adherence of Staphylococcus epidermidis and Pseudomonas alcaligenes to different intraocular lenses (IOLs. METHODS: Fourteen intraocular lenses were

  17. High-Speed 3D Printing of Millimeter-Size Customized Aspheric Imaging Lenses with Sub 7 nm Surface Roughness.

    Science.gov (United States)

    Chen, Xiangfan; Liu, Wenzhong; Dong, Biqin; Lee, Jongwoo; Ware, Henry Oliver T; Zhang, Hao F; Sun, Cheng

    2018-05-01

    Advancements in three-dimensional (3D) printing technology have the potential to transform the manufacture of customized optical elements, which today relies heavily on time-consuming and costly polishing and grinding processes. However the inherent speed-accuracy trade-off seriously constrains the practical applications of 3D-printing technology in the optical realm. In addressing this issue, here, a new method featuring a significantly faster fabrication speed, at 24.54 mm 3 h -1 , without compromising the fabrication accuracy required to 3D-print customized optical components is reported. A high-speed 3D-printing process with subvoxel-scale precision (sub 5 µm) and deep subwavelength (sub 7 nm) surface roughness by employing the projection micro-stereolithography process and the synergistic effects from grayscale photopolymerization and the meniscus equilibrium post-curing methods is demonstrated. Fabricating a customized aspheric lens 5 mm in height and 3 mm in diameter is accomplished in four hours. The 3D-printed singlet aspheric lens demonstrates a maximal imaging resolution of 373.2 lp mm -1 with low field distortion less than 0.13% across a 2 mm field of view. This lens is attached onto a cell phone camera and the colorful fine details of a sunset moth's wing and the spot on a weevil's elytra are captured. This work demonstrates the potential of this method to rapidly prototype optical components or systems based on 3D printing. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Intraocular pressure readings obtained through soft contact lenses using four types of tonometer

    Directory of Open Access Journals (Sweden)

    Takenaka J

    2015-10-01

    Full Text Available Joji Takenaka,1 Eriko Kunihara,1 Ulfah Rimayanti,2 Junko Tanaka,3 Makoto Kaneko,4 Yoshiaki Kiuchi1 1Department of Ophthalmology and Visual Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan; 2Faculty of Medicine and Health Sciences, UIN Alauddin Makassar, South Sulawesi, Indonesia; 3Department of Epidemiology, Infectious Disease Control and Prevention, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan; 4Graduate School of Engineering, Osaka University, Osaka, Japan Purpose: To compare the reliability and accuracy of intraocular pressure (IOP measured while wearing soft contact lenses (SCLs using a non-contact tonometer (NCT, Goldmann applanation tonometer (GAT, iCare rebound tonometer (RBT and the Tono-Pen XL.Methods: Twenty-six healthy subjects were examined. The IOP was measured using NCT, GAT, RBT, and the Tono-Pen XL, while the subjects wore SCLs -5.00 D, -0.50 D and +5.00 D. Bland–Altman plots and a regression analysis were used to compare the IOPs obtained with those instruments and the IOPs of the naked eyes measured using GAT (the standard IOPs in this study.Results: The IOPs obtained by the Tono-Pen XL while the subjects were wearing -5.00 D, -0.50 D, and +5.00 D SCLs were significantly higher than those of the naked eyes obtained using GAT. RBT showed that the IOPs were similar to the GAT standard IOPs under all conditions. The IOPs measured with NCT and GAT while the subjects were wearing -5.00 D and -0.50 D SCLs were similar to the GAT standard IOPs. The IOPs obtained with RBT and NCT while the subjects were wearing -5.00 D and -0.50 D SCLs exhibited a good correlation with the standard IOPs.Conclusion: The NCT and RBT are best when measuring IOP through hydrogel SCLs. Keywords: soft contact lens, intraocular pressure, rebound tonometer, non-contact tonometer

  19. Preliminary evaluation of an algorithm to minimize the power error selection of an aspheric intraocular lens by optimizing the estimation of the corneal power and the effective lens position

    Directory of Open Access Journals (Sweden)

    David P. Piñero

    2016-06-01

    Full Text Available AIM: To evaluate the refractive predictability achieved with an aspheric intraocular lens(IOLand to develop a preliminary optimized algorithm for the calculation of its power(PIOL.METHODS: This study included 65 eyes implanted with the aspheric IOL LENTIS L-313(Oculentis GmbHthat were divided into 2 groups: 12 eyes(8 patientswith PIOL≥23.0 D(group A, and 53 eyes(35 patientswith PIOLIOLadjwas calculated considering a variable refractive index for corneal power estimation, the refractive outcome obtained, and an adjusted effective lens position(ELPadjaccording to age and anatomical factors. RESULTS: Postoperative spherical equivalent ranged from -0.75 to +0.75 D and from -1.38 to +0.75 D in groups A and B, respectively. No statistically significant differences were found in groups A(P=0.64and B(P=0.82between PIOLadj and the IOL power implanted(PIOLReal. The Bland and Altman analysis showed ranges of agreement between PIOLadj and PIOLReal of +1.11 to -0.96 D and +1.14 to -1.18 D in groups A and B, respectively. Clinically and statistically significant differences were found between PIOLadj and PIOL obtained with Hoffer Q and Holladay I formulas(PCONCLUSION: The refractive predictability of cataract surgery with implantation of an aspheric IOL can be optimized using paraxial optics combined with linear algorithms to minimize the error associated to the estimation of corneal power and ELP.

  20. Phakic intraocular lenses for the treatment of refractive errors: an evidence-based analysis.

    Science.gov (United States)

    2009-01-01

    The objective of this analysis is to review the effectiveness, safety, and cost-effectiveness of phakic intraocular lenses (pIOLs) for the treatment of myopia, hyperopia, and astigmatism. CONDITION AND TARGET POPULATION REFRACTIVE ERRORS: Refractive errors occur when the eye cannot focus light properly. In myopia (near- or short-sightedness), distant objects appear blurry because the axis of the eye is too long or the cornea is too steep, so light becomes focused in front of the retina. Hyperopia (far sightedness) occurs when light is focused behind the retina causing nearby objects to appear blurry. In astigmatism, blurred or distorted vision occurs when light is focused at two points rather than one due to an irregularly shaped cornea or lens. Refractive errors are common worldwide, but high refractive errors are less common. In the United States, the prevalence of high myopia (≤ -5 D) in people aged 20 to 39, 40 to 59, and 60 years and older is 7.4% (95% confidence interval [CI], 6.5% - 8.3%), 7.8% (95% CI, 6.4% - 8.6%), and 3.1% (95% CI, 2.2% - 3.9%), respectively. The prevalence of high hyperopia (≥ 3 D) is 1.0% (95% CI, .6% - 1.4%), 2.4% (95% CI, 1.7% - 3.0%), and 10.0% (95% CI, 9.1% - 10.9%) for the same age groupings. Finally, the prevalence of astigmatism (≥ 1 D cylinder) is 23.1% (95% CI, 21.6% - 24.5%), 27.6% (95% CI, 25.8% - 29.3%) and 50.1% (48.2% - 52.0%). LOW VISION: According to the Ontario Schedule of Benefits, low visual acuity is defined by a best spectacle corrected visual acuity (BSCVA) of 20/50 (6/15) or less in the better eye and not amenable to further medical and/or surgical treatment. Similarly, the Ontario Assistive Devices Program defines low vision as BSCVA in the better eye in the range of 20/70 or less that cannot be corrected medically, surgically, or with ordinary eyeglasses or contact lenses. Estimates of the prevalence of low vision vary. Using the criteria of BSCVA ranging from 20/70 to 20/160, one study estimated that 35

  1. Photoprotection and photoreception of intraocular lenses under xenon and white LED illumination.

    Science.gov (United States)

    Artigas, J M; Navea, A; García-Domene, M C; Artigas, C; Lanzagorta, A

    2016-05-01

    To analyze the photoprotection and phototransmission that various intraocular lenses (IOLs) provide under the illumination of a xenon (Xe) lamp and white LEDs (light emitting diode). The spectral transmission curves of six representative IOLs were measured using a Perkin-Elmer Lambda 35 UV/VIS spectrometer. Various filtering simulations were performed using a Xe lamp and white LEDs. The spectral emissions of these lamps were measured with an ILT-950 spectroradiometer. The IOLs analyzed primarily show transmission of nearly 100% in the visible spectrum. In the ultraviolet (UV) region, the filters incorporated in the various IOLs did not filter equally, and some of them let an appreciable amount of UV through. The Xe lamp presented a strong emission of ultraviolet A (UVA), and its emission under 300nm was not negligible. The white LED did not present an appreciable emission under 380nm. The cut-off wavelength of most filters is between 380 and 400nm (Physiol Hydriol60C(®), IOLTECH E4T(®), Alcon SA60AT(®), Alcon IQ SN60WF(®)), so that their UV protection is very effective. Nonetheless, the IOL OPHTEC Oculaid(®) contains a filter that, when a Xe lamp is used, lets through up to 20% for 350nm and up to 15% for 300nm, which at this point is ultraviolet B (UVB). The OPHTEC(®) Artisan IOL has a transmission peak below 300nm, which must be taken into account under Xe illumination. White LEDs do not emit energy below 380nm, so no special protection is required in the UV region. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. Evaluation of rotation and visual outcomes after implantation of monofocal and multifocal toric intraocular lenses.

    Science.gov (United States)

    Garzón, Nuria; Poyales, Francisco; de Zárate, Begoña Ortíz; Ruiz-García, Jose Luis; Quiroga, Juan Antonio

    2015-02-01

    To evaluate rotational stability and its influence on postoperative visual acuity of different monofocal and multifocal toric intraocular lenses (IOLs). A prospective interventional study was designed. Ninety-one patients with a mean age of 71.65 ± 11.82 years were implanted with toric IOLs after phacoemulsification. Three monofocal toric IOLs (the Lentis LT [Oculentis, Berlin, Germany], enVista [Bausch & Lomb, Rochester, NY], and AcrySof IQ [Alcon Laboratories, Inc., Fort Worth, TX]) and one multifocal toric IOL (AcrySof IQ ReSTOR; Alcon Laboratories, Inc.) were implanted. Preoperative and postoperative images were taken to calculate the misalignment due to the marking method. To evaluate rotation in the different follow-up visits, another photograph was taken 1 hour and 1, 7 and 30 days postoperatively. Refraction, uncorrected distance visual acuity (UDVA), and corrected distance visual acuity were measured 30 days postoperatively. Postoperative UDVA was 0.1 logMAR or better in 64.6% of eyes implanted with monofocal IOLs and 46.4% of eyes implanted with multifocal IOLs. The enVista toric IOL showed the best UDVA compared to the other monofocal IOLs, with 81% of eyes with 0.1 logMAR or better. The mean misalignment in the total group studied was 0.07° ± 0.60°; 69.6% of monofocal IOLs and 67.9% of multifocal IOLs showed less than 5° of rotation. A correlation was found between postoperative UDVA and rotation in the monofocal and multifocal IOLs implanted (r = 0.439 [P < .011] and = 0.787 [P = .001], respectively). At 1 month postoperatively, UDVA was slightly more affected by IOL rotation in multifocal than monofocal toric IOLs. The marking method was also effective. Copyright 2015, SLACK Incorporated.

  3. Prevention of increased abnormal fundus autofluorescence with blue light-filtering intraocular lenses.

    Science.gov (United States)

    Nagai, Hiroyuki; Hirano, Yoshio; Yasukawa, Tsutomu; Morita, Hiroshi; Nozaki, Miho; Wolf-Schnurrbusch, Ute; Wolf, Sebastian; Ogura, Yuichiro

    2015-09-01

    To observe changes in fundus autofluorescence 2 years after implantation of blue light-filtering (yellow-tinted) and ultraviolet light-filtering (colorless) intraocular lenses (IOLs). Department of Ophthalmology and Visual Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, and the Department of Ophthalmology, University of Bern, Bern, Switzerland. Prospective comparative observational study. Patients were enrolled who had cataract surgery with implantation of a yellow-tinted or colorless IOL and for whom images were obtained on which the fundus autofluorescence was measurable using the Heidelberg Retina Angiogram 2 postoperatively. The fundus autofluorescence in the images was classified into 8 abnormal patterns based on the classification of the International Fundus Autofluorescence Classification Group, The presence of normal fundus autofluorescence, geographic atrophy, and wet age-related macular degeneration (AMD) also was recorded. The fundus findings at baseline and 2 years postoperatively were compared. Fifty-two eyes with a yellow-tinted IOL and 79 eyes with a colorless IOL were included. Abnormal fundus autofluorescence did not develop or increase in the yellow-tinted IOL group; however, progressive abnormal fundus autofluorescence developed or increased in 12 eyes (15.2%) in the colorless IOL group (P = .0016). New drusen, geographic atrophy, and choroidal neovascularization were observed mainly in the colorless IOL group. The incidence of AMD was statistically significantly higher in the colorless IOL group (P = .042). Two years after cataract surgery, significant differences were seen in the progression of abnormal fundus autofluorescence between the 2 groups. The incidence of AMD was lower in eyes with a yellow-tinted IOL. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  4. Moxifloxacin superior to cefuroxime in reducing bacterial adhesion of Staphylococcus epidermidis on hydrophobic intraocular lenses.

    Science.gov (United States)

    Benbouzid, Fathalah; Kodjikian, Laurent; Hartmann, Daniel; Renaud, François; Baillif, Stéphanie

    2016-02-01

    To compare the anti-adhesive effect of cefuroxime and moxifloxacin on the primary attachment phase of Staphylococcus epidermidis on hydrophobic acrylic intraocular lenses (IOLs). Forty hydrophobic acrylic IOLs were used. Two groups of IOLs were soaked in a moxifloxacin (Mox-T1: 0.5 mg/0.1 ml) or a cefuroxime (Cef-T1: cefuroxime 1 mg/0.1 ml) solution before incubation in a S. epidermidis bacterial suspension. Two other groups were incubated in the bacterial suspension before antibiotics (Cef-T2 and Mox-T2) were added. The control group (Ctrl) consisted of IOLs incubated in the bacterial suspension. After incubation, IOLs were sonicated and vortexed. The resultant suspension was spread over a nutritive agar plate. Bacterial colonies were counted after 24 hr of incubation. Mean number of colony-forming units per IOL was Cef-T1: 184 × 10(3) (SE: 5.24; SD: 28.21), Cef-T2: 117 × 10(3) (SE: 5.74; SD: 30.37), Mox-T1: 1.27 × 10(3) (SE: 0.12; SD: 0.61), Mox-T2: 25 × 10(3) (SE:1.98; SD: 9.72) and Ctrl: 361 × 10(3) (SE: 26.9; SD: 107.6). The number of adhering bacteria did not vary whether cefuroxime was added before or after IOL incubation in the bacterial suspension (p = 0.132). Moxifloxacin was more effective in reducing the number of adhering bacteria when used before IOL incubation (p < 0.001). Overall for T1 and T2, moxifloxacin was more effective than cefuroxime in reducing bacterial adhesion on IOLs (p < 0.001). Moxifloxacin and cefuroxime significantly reduced S. epidermidis adhesion on hydrophobic acrylic IOLs. The anti-adhesive effect was superior with moxifloxacin. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  5. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models.

    Science.gov (United States)

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-11

    In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3 mm of pupil diameter and from 0 to out-of-focus blur were collected and graphed. MTF values, measured at 555 nm of monochromatic light under each spatial frequency, were significantly higher than the values measured at 470 to 650 nm of polychromatic light. The influences of chromatic aberration on MTF values decreased with the increase in IOL diopter when the spatial frequency was ≤12 c/d, while increased effects were observed when the spatial frequency was ≥15 c/d. The MTF values of each IOL eye model were significantly lower than the MTF values of the Liou-Brennan eye models when measured at 555 nm of monochromatic light and at 470 to 650 nm of polychromatic light. The MTF values were also found to be increased with the increase in IOL diopter. With higher diopters of IOLs, the central thickness increased accordingly, which could have created increased chromatic aberration and decreased the retinal image quality. To improve the postoperative visual quality, IOLs with lower chromatic aberration should be selected for patients with short axial lengths.

  6. Comparison of visual outcomes after bilateral implantation of extended range of vision and trifocal intraocular lenses.

    Science.gov (United States)

    Ruiz-Mesa, Ramón; Abengózar-Vela, Antonio; Aramburu, Ana; Ruiz-Santos, María

    2017-06-26

    To compare visual outcomes after cataract surgery with bilateral implantation of 2 intraocular lenses (IOLs): extended range of vision and trifocal. Each group of this prospective study comprised 40 eyes (20 patients). Phacoemulsification followed by bilateral implantation of a FineVision IOL (group 1) or a Symfony IOL (group 2) was performed. The following outcomes were assessed up to 1 year postoperatively: binocular uncorrected distance visual acuity (UDVA), binocular uncorrected intermediate visual acuity (UIVA) at 60 cm, binocular uncorrected near visual acuity (UNVA) at 40 cm, spherical equivalent (SE) refraction, defocus curves, mesopic and photopic contrast sensitivity, halometry, posterior capsule opacification (PCO), and responses to a patient questionnaire. The mean binocular values in group 1 and group 2, respectively, were SE -0.15 ± 0.25 D and -0.19 ± 0.18 D; UDVA 0.01 ± 0.03 logMAR and 0.01 ± 0.02 logMAR; UIVA 0.11 ± 0.08 logMAR and 0.09 ± 0.08 logMAR; UNVA 0.06 ± 0.07 logMAR and 0.17 ± 0.06 logMAR. Difference in UNVA between IOLs (pvisual outcomes. The FineVision IOL showed better near visual acuity. Predictability of the refractive results and optical performance were excellent; all patients achieved spectacle independence. The 2 IOLs gave similar and good contrast sensitivity in photopic and mesopic conditions and low perception of halos by patients.

  7. Reproducibility analysis of measurements with a mechanical semiautomatic eye model for evaluation of intraocular lenses

    Science.gov (United States)

    Rank, Elisabet; Traxler, Lukas; Bayer, Natascha; Reutterer, Bernd; Lux, Kirsten; Drauschke, Andreas

    2014-03-01

    Mechanical eye models are used to validate ex vivo the optical quality of intraocular lenses (IOLs). The quality measurement and test instructions for IOLs are defined in the ISO 11979-2. However, it was mentioned in literature that these test instructions could lead to inaccurate measurements in case of some modern IOL designs. Reproducibility of alignment and measurement processes are presented, performed with a semiautomatic mechanical ex vivo eye model based on optical properties published by Liou and Brennan in the scale 1:1. The cornea, the iris aperture and the IOL itself are separately changeable within the eye model. The adjustment of the IOL can be manipulated by automatic decentration and tilt of the IOL in reference to the optical axis of the whole system, which is defined by the connection line of the central point of the artificial cornea and the iris aperture. With the presented measurement setup two quality criteria are measurable: the modulation transfer function (MTF) and the Strehl ratio. First the reproducibility of the alignment process for definition of initial conditions of the lateral position and tilt in reference to the optical axis of the system is investigated. Furthermore, different IOL holders are tested related to the stable holding of the IOL. The measurement is performed by a before-after comparison of the lens position using a typical decentration and tilt tolerance analysis path. Modulation transfer function MTF and Strehl ratio S before and after this tolerance analysis are compared and requirements for lens holder construction are deduced from the presented results.

  8. Subluxation of suture-fixated posterior chamber intraocular lenses a clinicopathologic study.

    Science.gov (United States)

    Parekh, Parag; Green, W Richard; Stark, Walter J; Akpek, Esen Karamursel

    2007-02-01

    To report the occurrence of subluxation of suture-fixated posterior chamber (PC) intraocular lenses (IOL) and elucidate the mechanisms involved. Prospective clinicopathologic study. A single 10-0 Prolene suture explanted from a patient who experienced subluxation of his PC-IOL, 11.5 years after placement. Furthermore, multiple 10-0 Prolene sutures and PC-IOLs used for iris fixation were studied as controls. Scanning electron microscopy (SEM) was used to analyze the surface of the explanted suture. In addition, randomly selected 10-0 Prolene sutures cut with Vannas scissors and cut with the positioning holes of a randomly selected PC-IOL identical to that implanted in the patient's eye were examined as controls. Finally, the positioning holes of several randomly selected, iris-fixated PC-IOLs were studied using SEM with particular attention to surface quality and edge finish. Presence of any signs of suture degradation, the character of the cut edge of the suture, as well as the characteristics of the positioning holes of the PC-IOLs. Scanning electron microscopy of the explanted suture revealed sharply cut edges, without significant degradation of the suture, and no intact loop. Scanning electron microscopy of the control suture cut with a PC-IOL demonstrated a similarly cut edge. The positioning holes of the examined PC-IOLs had a sharp edge, and some also had an imperfect finish. We conclude that the surface properties of the positioning holes lead to cutting of the suture, and subsequent subluxation of the PC-IOL.

  9. [Cause analysis and management of severe dislocated or subluxated intraocular lenses in the capsular bag].

    Science.gov (United States)

    Wang, Wen-qing; Jia, Li-Li; Lu, Bin; Fang, Jian; Chen, Ying

    2006-05-01

    To analyze the causes of severe dislocated and subluxated intraocular lenses (IOL) in capsular bag and the relevancy with abnormal capsular constitution. The abnormality of capsular and the position of IOL were retrospectively analyzed by slit lamp and microscope in dilated pupil. Surgeries were performed in all of 31 cases in order to exchange or reposit the dislocated or subluxated lOL. Among 31 cases, there were 20 cases with the dislocated or subluxated IOL in the earlier postoperative period and 11 cases in the later postoperative period. The subluxated IOL in 5 cases (16.1%) were caused by the large rupture of the posterior capsular, and by the rupture of the posterior capsular in 9 cases (29.0%). A upward subluxated IOL developed in one case (3.2%) as the result of small rupture in the equater capsular. The subluxatd IOL in the anterior chamber in two cases (6.5%) was induced by the radial rupture of residual anterior capsular. The size of the IOLs in 2 cases were not matched to the diameter of the capsule bag. The dislocated IOL into the vitreous in 2 cases was caused by the rupture of the superior capsular. The subluxated IOL in 2 cases (6.5%) was caused by the zonal finers rupture due to trauma. The severe disfiguration of the IOL haptic was found in one case. The dislocated IOL in 6 cases (19.4%) was caused by asymmetric capsular shrinkage. A subluxated IOL in one case was resulted from the zonular defects with pseudoexfoliation syndrome. The postoperative corrected visual acuity was 0.5 - 1.0 in 24 eyes, 0.1 - 0.4 in 6 eyes, and 0.05 in one eye. There are several causes for the dislocated or subluxated IOL. The correction of the IOL position should depend on the cause for the dislocated or subluxated IOL.

  10. The effect of blue-blocking and neutral intraocular lenses on circadian photoentrainment and sleep one year after cataract surgery

    DEFF Research Database (Denmark)

    Brøndsted, Adam Elias; Haargaard, Birgitte; Sander, Birgit

    2017-01-01

    surgery with implantation of either a neutral or a blue-blocking intraocular lens (IOL). Main outcome was activation of the intrinsically photosensitive retinal ganglion cells (ipRGC) measured by chromatic pupillometry. The circadian rhythm was analysed by 24-hr melatonin profiles and actigraphy......PURPOSE: To compare the long-term effect on circadian photoentrainment and sleep in patients implanted with neutral and blue-blocking intraocular lenses 1 year after cataract surgery. METHODS: Randomized, controlled trial involving 67 patients with age-related cataract. Intervention was cataract...... compared with neutral IOLs. Cataract surgery improved the response of ipRGCs and sleep quality. However, the effect of cataract surgery on sleep quality may be unrelated to circadian photoentrainment....

  11. Near-point string: Simple method to demonstrate anticipated near point for multifocal and accommodating intraocular lenses.

    Science.gov (United States)

    George, Monica C; Lazer, Zane P; George, David S

    2016-05-01

    We present a technique that uses a near-point string to demonstrate the anticipated near point of multifocal and accommodating intraocular lenses (IOLs). Beads are placed on the string at distances corresponding to the near points for diffractive and accommodating IOLs. The string is held up to the patient's eye to demonstrate where each of the IOLs is likely to provide the best near vision. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  12. Intraocular pressure measurements in relation to head position and through soft contact lenses: comparison of three portable instruments.

    Science.gov (United States)

    Klein, Ainat; Shemesh, Gabi; Loewenstein, Anat; Kurtz, Shimon

    2011-01-01

    to compare the reproducibility of three portable instruments-the Tono-Pen tonometer (Reichert Ophthalmic Instruments, Depew, NY), the Phosphene tonometer (Bausch & Lomb, Rochester, NY), and the TERT (Through Eyelid Russian Tonometer; Rjazan State Instrument Making, Rjazan, Russia)-in the measurement of intraocular pressure (IOP) with and without soft contact lenses and in different head positions. twenty-six eyes of healthy volunteers were examined by the three instruments while the subjects were sitting, recumbent, and hyperextending their heads, and with and without contact lenses. IOP measurements were compared and the effects of head position and presence of contact lenses on the resultant values were analyzed. the average difference between the recumbent and sitting positions was 3.56, 2.68, and 2.62 mm Hg for the Tono-Pen tonometer, Phosphene tonometer, and TERT, respectively. There was an increase of 5.60, 2.78, and 2.63 mm Hg in hyperextension compared to sitting for the Tono-Pen tonometer, Phosphene tonometer, and TERT, respectively. The difference in the IOP values obtained in the presence and absence of therapeutic contact lens for the three instruments in the three positions was between -1.23 and +1.47 mm Hg. IOP measurements of bedridden patients are only slightly higher than those of sitting patients except for the Tono-Pen tonometer in the hyperextension position. The presence of contact lenses does not affect IOP values obtained by the three evaluated instruments.

  13. [Opacification of an intraocular lens: calcification of hydrophilic intraocular lenses after gas tamponade of the anterior chamber].

    Science.gov (United States)

    Schmidinger, G; Pemp, B; Werner, L

    2013-11-01

    A patient with endothelial dystrophy was treated with Descemet stripping automated endothelial keratoplasty (DSAEK) combined with cataract extraction and implantation of a hydrophilic intraocular lens (IOL, Lentis-L312, Oculentis) but visual acuity dropped from 0.15 logMAR to 0.52 logMAR 18 months later due to calcification of the IOL. With new methods of lamellar corneal transplantation being used more frequently the number of necessary anterior chamber tamponades with air/gas are increasing. In cataract cases in which a gas tamponade and transplantation might be necessary later on (cornea guttata), hydrophilic IOLs should be avoided.

  14. Comparison of clinical performance between trifocal and bifocal intraocular lenses: A meta-analysis.

    Directory of Open Access Journals (Sweden)

    Zequan Xu

    Full Text Available To compare the clinical performance between trifocal and bifocal intraocular lenses in bilateral cataract and/or refractive lens exchange (RLE surgery.A comprehensive literature search of PubMed, EMBASE, Cochrane Controlled Trials Register and Web of Science was performed through October 2016 to identify randomized, controlled trials (RCTs and comparative cohort studies. The primary outcomes were uncorrected distance visual acuity (UDVA, uncorrected intermediate visual acuity (UIVA, uncorrected near visual acuity (UNVA, defocus curve, spectacle independence, patient satisfaction and contrast sensitivity. The secondary outcomes were residual sphere, spherical equivalent (SE, cylinder and complications.Six RCTs and 2 cohort studies including 568 eyes (278 in the trifocal group and 290 in the bifocal group were identified. There was a statically significant difference between the two groups in UDVA (WMD: -0.03, 95% CI: -0.05 to -0.01, P = 0.005, but the difference (0.03 log MAR is not clinically significant. Intermediate visual acuity was better in the trifocal IOL group judging from UIVA and defocus curves. There was a statically significant difference between the two groups in residual cylinder (WMD: 0.11, 95% CI: 0.02 to 0.20, P = 0.02, and subgroup AT Lisa tri 839MP trifocal also showed significant better UNVA than bifocal IOLs (WMD: -0.13, 95% CI: -0.17 to -0.08, P<0.00001. However, no significant differences were observed in UNVA (WMD: -0.04, 95% CI: -0.11 to 0.02, P = 0.19, spectacle independence (WMD: 1.27, 95% CI: 0.89 to 18.15, P = 0.07, patient satisfaction (WMD: 4.01, 95% CI: 0.07 to 22.72, P = 0.87, residual sphere (WMD: -0.03, 95% CI: -0.18 to 0.13, P = 0.74, SE (WMD: 0.04, 95% CI: -0.09 to 0.16, P = 0.55 or complications (WMD: 2.08, 95% CI: 0.35 to 12.43, P = 0.42.Trifocal IOL technology (especially AT Lisa trifocal 839M trifocal had a clear advantage over bifocal IOLs in intermediate visual acuity, while both trifocal IOLs and

  15. Magnifications of Single and Dual Element Accommodative Intraocular Lenses: Paraxial Optics Analysis

    Science.gov (United States)

    Ale, Jit B; Manns, Fabrice; Ho, Arthur

    2010-01-01

    Purpose Using an analytical approach of paraxial optics, we evaluated the magnification of a model eye implanted with single-element (1E) and dual-element (2E) translating-optics accommodative intraocular lenses (AIOL) with an objective of understanding key control parameters relevant to their design. Potential clinical implications of the results arising from pseudophakic accommodation were also considered. Methods Lateral and angular magnifications in a pseudophakic model eye were analyzed using the matrix method of paraxial optics. The effects of key control parameters such as direction (forward or backward) and distance (0 to 2 mm) of translation, power combinations of the 2E-AIOL elements (front element power range +20.0 D to +40.0 D), and amplitudes of accommodation (0 to 4 D) were tested. Relative magnification, defined as the ratio of the retinal image size of the accommodated eye to that of unaccommodated phakic (rLM1) or pseudophakic (rLM2) model eyes, was computed to determine how retinal image size changes with pseudophakic accommodation. Results Both lateral and angular magnifications increased with increased power of the front element in 2E-AIOL and amplitude of accommodation. For a 2E-AIOL with front element power of +35 D, rLM1 and rLM2 increased by 17.0% and 16.3%, respectively, per millimetre of forward translation of the element, compared to the magnification at distance focus (unaccommodated). These changes correspond to a change of 9.4% and 6.5% per dioptre of accommodation, respectively. Angular magnification also increased with pseudophakic accommodation. 1E-AIOLs produced consistently less magnification than 2E-AIOLs. Relative retinal image size decreased at a rate of 0.25% with each dioptre of accommodation in the phakic model eye. The position of the image space nodal point shifted away from the retina (towards the cornea) with both phakic and pseudophakic accommodation. Conclusion Power of the mobile element, and amount and direction of

  16. Comparison of outcomes with multifocal intraocular lenses: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Béatrice Cochener

    2011-01-01

    Full Text Available Béatrice Cochener1, Antoine Lafuma2, Babak Khoshnood2, Laurène Courouve2, Gilles Berdeaux3,41Centre Hospitalier Universitaire Brest, Brest, France; 2Cemka Eval, Bourg la Reine, France; 3Alcon France, Rueil-Malmaison, France; 4Conservatoire National des Arts et Métiers, Paris, FrancePurpose: To compare the clinical outcome of different multifocal intraocular lenses (IOLs based on information reported in the international literature.Methods: All comparative clinical trials that involved implanting at least one multifocal IOL in patients with cataract or presbyopia were extracted from the literature. Clinical outcomes included uncorrected near visual acuity, uncorrected distance visual acuity, visual acuity, spectacle independence, and halos. Random effects meta-analyses were conducted to compare outcomes for the different IOL types.Results: Twenty papers were identified describing 11 monofocal IOLs and 35 multifocal IOLs (19 diffractive, including 12 ReSTOR®, 14 refractive, and two accommodative patient cohorts. Multifocal and monofocal uncorrected distance visual acuity was 0.165 (0.090–0.240 and 0.093 (0.088–0.098, respectively. Compared with monofocal IOLs, multifocal IOLs produced better uncorrected near visual acuity (0.470 [0.322–0.618] versus 0.141 [0.131–0.152]; P < 0.0001, resulting in higher spectacle independence (incidence rate ratio [IRR] 3.62 [2.90–4.52]; P < 0.0001. Compared with refractive multifocal IOLs, diffractive multifocal IOLs produced a similar uncorrected distance visual acuity (0.105 [0.098–0.111] versus 0.085 [0.029–0.140]; P ≤ 0.78, not significant and better uncorrected near visual acuity (0.217 [0.118–0.317] versus 0.082 [0.067–0.098]; P < 0.0001 resulting in higher spectacle independence (IRR 1.75 [1.24–2.48]; P < 0.001. Compared with other multifocal IOLs, ReSTOR produced a better uncorrected distance visual acuity (0.067 [0.059–0.076] versus 0.093 [0.088–0.098]; P < 0.0001 and better

  17. Aderência bacteriana in vitro a lentes intra-oculares de polimetilmetacrilato e de silicone In vitro bacterial adherence to silicone and polymetylmethacrylate intraocular lenses

    Directory of Open Access Journals (Sweden)

    Claudete Inês Locatelli

    2004-04-01

    Full Text Available OBJETIVOS: Verificar a aderência bacteriana a lentes intra-oculares de silicone e de polimetilmetacrilato como possível fator de risco no desenvolvimento de endoftalmite pós-operatória, utilizando-se um modelo in vitro com três microrganismos potencialmente patogênicos. MÉTODOS: As análises foram realizadas com cepas de Staphylococcus aureus ATCC 29213, Staphylococcus epidermidis (amostra clínica e Pseudomonas aeruginosa ATCC 27853 incluindo a determinação de curvas de crescimento, testes para verificação de produção de cápsula, avaliação da hidrofobicidade, testes de aderência a diferentes materiais, microscopia óptica, microscopia eletrônica de varredura e microscopia de força atômica. RESULTADOS: A produção de cápsula e a aderência das três diferentes cepas não mostraram qualquer relação com a quantidade de microrganismos; em relação às lentes intra-oculares de polimetilmetacrilato e de silicone, não houve diferença estatisticamente significativa na aderência de S. aureus e S. epidermidis; P. aeruginosa foi o microrganismo mais aderente a ambos os materiais. A microscopia eletrônica de varredura confirmou estes achados em relação à aderência, ao peso que a microscopia de força atômica evidenciou a produção de biofilme pelas cepas de S. aureus, S. epidermidis e P. aeruginosa. CONCLUSÕES: Constatou-se, in vitro, que os materiais analisados não diferiram com relação à taxa de aderência bacteriana, porém, P. aeruginosa apresentou maior eficiência de adesão entre as bactérias testadas. Todas as cepas produziram biofilme. Silicone foi o material mais hidrofóbico, quando comparado ao polimetilmetacrilato.PURPOSE: To evaluate bacterial adherence to silicone and polymetylmethacrylate (PMMA intraocular lenses as a risk factor for postsurgery endophthalmitis by using an in vitro model with three potentially pathogenic microorganisms. METHODS: In vitro experiments were carried out with the

  18. Neodymium: YAG laser damage threshold. A comparison of injection-molded and lathe-cut polymethylmethacrylate intraocular lenses.

    Science.gov (United States)

    Wilson, S E; Brubaker, R F

    1987-01-01

    The possibility that injection-molded intraocular lenses (IOLs) with imperfections called iridescent clefts could have a decreased threshold to neodymium: YAG (Nd:YAG) laser-induced damage was investigated. Thresholds for Nd:YAG laser-induced damage were determined for injection-molded and lathe-cut polymethylmethacrylate lenses. When aimed at a membrane in contact with a posterior convex surface, the average thresholds were 0.96 +/- 0.18 mJ (Standard deviation [SD]) and 1.80 +/- 0.55 mJ, respectively. The difference was significant at P = 0.001. When injection-molding polymethylmethacrylate was used to make lathe-cut IOLs, very few iridescent clefts were present, and the threshold to Nd:YAG laser-induced damage was 0.94 +/- 0.25 mJ. Iridescent clefts are therefore produced during the injection-molding process but they do not lower the threshold to Nd:YAG laser-induced damage. Rather, the reduced threshold in injection-molded lenses is most probably a result of the polymethylmethacrylate used in their manufacture. Clinically, iridescent clefts in a lens suggest that it has been manufactured by an injection-molding process and that Nd:YAG laser posterior capsulotomy must be performed at the lowest possible energy level to avoid damage.

  19. Results of intraocular lens implantation with capsular tension ring in subluxated crystalline or cataractous lenses in children.

    Science.gov (United States)

    Das, Pranab; Ram, Jagat; Brar, Gagandeep Singh; Dogra, Mangat R

    2009-01-01

    To evaluate the outcome of intraocular lens (IOL) implantation using capsular tension ring (CTR) in subluxated crystalline or cataractous lenses in children. Tertiary care setting. We prospectively studied 18 eyes of 15 children with subluxation of crystalline or cataractous lenses between 90 degrees up to 210 degrees after phacoemulsification, CTR and IOL implantation. Each child was examined for IOL centration, zonular dehiscence and posterior capsular opacification (PCO). Age of the patient ranged between five to 15 years. Out of 18 eyes, seven had traumatic and 11 had spontaneous subluxation of crystalline or cataractous lens. Phacoemulsification was successfully performed with CTR implantation in the capsular bag. Intraoperative zonular dialysis occurred in two eyes. Anterior vitrectomy was performed in six eyes to manage vitreous prolapse. IOL implanted was polymethyl methacrylate (PMMA) in eight eyes, hydrophobic acrylic in seven and hydrophilic acrylic in three. Follow-up ranged from 24 months to 72 months. Sixteen eyes had a best corrected visual acuity of 20/40 or better. Nine eyes developed significant PCO and were managed with Neodymium Yttrium Aluminum Garnet (Nd:YAG) laser posterior capsulotomy. One eye with acrylic IOL in the capsular bag had IOL dislocation after two years which was managed with vitrectomy and secondary trans-scleral fixation of IOL. Phacoaspiration with CTR implantation makes capsular bag IOL fixation possible in most of the eyes with subluxated crystalline or cataractous lenses. PCO still remains a challenge in children with successful phacoaspiration with CTR implantation.

  20. Results of intraocular lens implantation with capsular tension ring in subluxated crystalline or cataractous lenses in children

    Directory of Open Access Journals (Sweden)

    Das Pranab

    2009-01-01

    Full Text Available Purpose : To evaluate the outcome of intraocular lens (IOL implantation using capsular tension ring (CTR in subluxated crystalline or cataractous lenses in children. Setting : Tertiary care setting Materials and Methods : We prospectively studied 18 eyes of 15 children with subluxation of crystalline or cataractous lenses between 90° up to 210° after phacoemulsification, CTR and IOL implantation. Each child was examined for IOL centration, zonular dehiscence and posterior capsular opacification (PCO. Results : Age of the patient ranged between five to 15 years. Out of 18 eyes, seven had traumatic and 11 had spontaneous subluxation of crystalline or cataractous lens. Phacoemulsification was successfully performed with CTR implantation in the capsular bag. Intraoperative zonular dialysis occurred in two eyes. Anterior vitrectomy was performed in six eyes to manage vitreous prolapse. IOL implanted was polymethyl methacrylate (PMMA in eight eyes, hydrophobic acrylic in seven and hydrophilic acrylic in three. Follow-up ranged from 24 months to 72 months. Sixteen eyes had a best corrected visual acuity of 20/40 or better. Nine eyes developed significant PCO and were managed with Neodymium Yttrium Aluminum Garnet (Nd:YAG laser posterior capsulotomy. One eye with acrylic IOL in the capsular bag had IOL dislocation after two years which was managed with vitrectomy and secondary trans-scleral fixation of IOL. Conclusions : Phacoaspiration with CTR implantation makes capsular bag IOL fixation possible in most of the eyes with subluxated crystalline or cataractous lenses. PCO still remains a challenge in children with successful phacoaspiration with CTR implantation

  1. The measurement of intraocular pressure over positive soft contact lenses by rebound tonometry

    Directory of Open Access Journals (Sweden)

    Fabrizio Zeri

    2016-07-01

    Conclusions: Rebound tonometry over positive hydrogel CLs leads to a certain degree of IOP underestimation. This result did not change for the two positive lenses used in the experiment, despite their large difference in power and therefore in lens thickness. Optometrists should bear this in mind when measuring IOP with the rebound tonometer over plus power contact lenses.

  2. Construction, specification, and mathematical description of aspheric surfaces.

    Science.gov (United States)

    Smith, G; Atchison, D A

    1983-03-01

    Rotationally symmetrical aspheric surfaces of spectacle lenses are constructed as either "zonal aspherics" or "continuous aspherics." Zonal aspherics consist of annular zones surrounding a central zone with each zone being nominally spherical with progressively lower surface power the farther the zone is from the surface vertex. Aspheric surfaces are often specified by the radial drop in surface power from the center to the edge of the lens (e.g., Welsh Four-drop), but for assessment purposes the surface shape must be specified more precisely. The formulas for the description of continuous aspherics can be manipulated into different forms. Mathematical descriptions are given or developed which will enable theoretical assessment of the performances of all lenses with rotationally symmetrical aspheric surfaces.

  3. An intuitive concept for manufacturing and inspecting of aspherical components

    Science.gov (United States)

    Chou, Hsiao-Yu; Chang, Keng-Shou

    2011-09-01

    In this paper we propose an intuitive concept for manufacturing and inspecting of aspherical components. Two types, parabolic and cylinder, of plano-convex and plano-concave aspherical lenses were made by LOH 120S form generation machine. Three form error measurement methods were used known as coordinate measuring machine (CMM), interferometer with CGH null lens and inspection with combined pair lenses. Ultra high accuracy CMM from Panasonic Co., CGH cylinder null and CGH aspheric null from Diffraction International and OWI 150 ASPH CGH interferometer from OptoTech GmbH play the roll for measurement. CMM was used as a surface profiler to inspect the surface shape, and the software GRAPHER was also used as analysis tool to exam asphere numerical datum. The difference between theoretical and practical is as a surface polishing revised reference. The finished plano-convex and plano-concave aspherical lenses can be combined to be a plane lens. The individual and combined lenses were inspected on OPTOTECH OWI 150 ASPH CGH interferometer. The compared interference patterns have shown with the Diffration International CGH Aspheric Null "ASPHERIC 1" and CGH Cylinder Null "H80F2C". Through the procedure, the combined plano-convex and plano-concave aspherical lenses should be a perfect match plane lens and the individual lens might be an aspherical test standard element for quick inspection.

  4. A novel full-angle scanning light scattering profiler to quantitatively evaluate forward and backward light scattering from intraocular lenses

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Bennett N., E-mail: bennett.walker@fda.hhs.gov [Optical Therapeutics and Medical Nanophotonics Laboratory, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993 (United States); Office of Device Evaluation, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland 20993 (United States); James, Robert H.; Ilev, Ilko K. [Optical Therapeutics and Medical Nanophotonics Laboratory, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993 (United States); Calogero, Don [Office of Device Evaluation, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland 20993 (United States)

    2015-09-15

    Glare, glistenings, optical defects, dysphotopsia, and poor image quality are a few of the known deficiencies of intraocular lenses (IOLs). All of these optical phenomena are related to light scatter. However, the specific direction that light scatters makes a critical difference between debilitating glare and a slightly noticeable decrease in image quality. Consequently, quantifying the magnitude and direction of scattered light is essential to appropriately evaluate the safety and efficacy of IOLs. In this study, we introduce a full-angle scanning light scattering profiler (SLSP) as a novel approach capable of quantitatively evaluating the light scattering from IOLs with a nearly 360° view. The SLSP method can simulate in situ conditions by controlling the parameters of the light source including angle of incidence. This testing strategy will provide a more effective nonclinical approach for the evaluation of IOL light scatter.

  5. A novel full-angle scanning light scattering profiler to quantitatively evaluate forward and backward light scattering from intraocular lenses

    International Nuclear Information System (INIS)

    Walker, Bennett N.; James, Robert H.; Ilev, Ilko K.; Calogero, Don

    2015-01-01

    Glare, glistenings, optical defects, dysphotopsia, and poor image quality are a few of the known deficiencies of intraocular lenses (IOLs). All of these optical phenomena are related to light scatter. However, the specific direction that light scatters makes a critical difference between debilitating glare and a slightly noticeable decrease in image quality. Consequently, quantifying the magnitude and direction of scattered light is essential to appropriately evaluate the safety and efficacy of IOLs. In this study, we introduce a full-angle scanning light scattering profiler (SLSP) as a novel approach capable of quantitatively evaluating the light scattering from IOLs with a nearly 360° view. The SLSP method can simulate in situ conditions by controlling the parameters of the light source including angle of incidence. This testing strategy will provide a more effective nonclinical approach for the evaluation of IOL light scatter

  6. The effect of hydrogel and silicone hydrogel contact lenses on the measurement of intraocular pressure with rebound tonometry.

    Science.gov (United States)

    Zeri, Fabrizio; Calcatelli, Paolo; Donini, Bernardo; Lupelli, Luigi; Zarrilli, Luciana; Swann, Peter G

    2011-12-01

    To assess the accuracy of intraocular pressure (IOP) measurements using rebound tonometry over disposable hydrogel (etafilcon A) and silicone hydrogel (senofilcon A) contact lenses (CLs) of different powers. The experimental group comprised 36 subjects (19 male, 17 female). IOP measurements were undertaken on the subject's right eyes in random order using a rebound tonometer (ICare). The CLs had powers of +2.00D, -2.00D and -6.00D. Six measurements were taken over each contact lens and also before and after the CLs had been worn. A good correlation was found between IOP measurements with and without CLs (all r≥0.80; pContact Lens Association. Published by Elsevier Ltd. All rights reserved.

  7. Staphylococcus epidermidis biofilm formation and structural organization on different types of intraocular lenses under in vitro flow conditions.

    Science.gov (United States)

    Baillif, Stéphanie; Leduff, Frank; Hartmann, Daniel J; Kodjikian, Laurent

    2013-01-01

    To compare the adherence and structural organization of Staphylococcus epidermidis biofilm on intraocular lenses (IOLs). IOLs made of 3 different biomaterials [polymethyl methacrylate (PMMA), hydrophilic acrylic or hydrophobic acrylic] were incubated into an S. epidermidis bacterial solution. Scanning electron microscopy was used to count the bound bacteria and to analyze the structural biofilm architecture. After 4-6 h of incubation, adherence was statistically weakest on the hydrophilic acrylic polymer. On the hydrophobic acrylic material, the bacterial cells tended to cover the substratum in a horizontal spread in a continuous monolayer. On the hydrophilic acrylic material or on the PMMA material bacterial cells tended to form only few, small scattered cell clusters. The data suggest that the pattern of S. epidermidis adhesion varies with the IOL biomaterial. Hydrophobic IOLs seem to be more permissive to S. epidermidis adhesion. Copyright © 2013 S. Karger AG, Basel.

  8. Comparison between bilateral implantation of a trifocal intraocular lens and blended implantation of two bifocal intraocular lenses

    Directory of Open Access Journals (Sweden)

    Vilar C

    2017-08-01

    Full Text Available César Vilar,1,2 Wilson Takashi Hida,1–3 André Lins de Medeiros,1,2 Klayny Rafaella Pereira Magalhães,2 Patrick Frensel de Moraes Tzelikis,1,2 Mario Augusto Pereira Dias Chaves,2,4 Antônio Francisco Pimenta Motta,2,3 Pedro Carlos Carricondo,1–3 Milton Ruiz Alves,3 Walton Nosé5 1Cataract Division, Brasília Ophthalmologic Hospital (HOB, Brasília-DF, Brazil; 2Renato Ambrosio Ophthalmologic Research Center (CEORA, 3Ophthalmology Department, São Paulo University – USP, São Paulo-SP, Brazil; 4Cataract Division, ProVisão, João Pessoa-PB, Brazil; 5Ophthalmology Department, Paulista Medical School – UNIFESP, São Paulo-SP, Brazil Purpose: To compare visual outcomes and performance between bilateral implantation of a diffractive trifocal intraocular lens (IOL Acrysof®PanOptix® TFNT00 and blended implantation of two different near add power bifocal IOLs: Acrysof® Restor® SV25T0 in dominant eye and Acrysof® Restor® SN6AD1 in the nondominant eye.Methods: This prospective, nonrandomized, consecutive and comparative study assessed 20 patients (40 eyes who had bilateral cataract surgery performed using the IOLs described. Patients were divided into groups, bilateral trifocal implant and blended implant. Evaluation included measurement of binocular uncorrected and corrected distance visual acuity at 4 m (UDVA, CDVA and uncorrected intermediate (60 cm and near (at 40 cm visual acuity; contrast sensitivity (CS and visual defocus curve.Results: Postoperative CDVA comparison showed no statistical significance between groups. UDVA was significantly better in the trifocal groups. Under photopic conditions, the trifocal group had better CS in higher frequencies with and without glare. The binocular defocus curve demonstrated a trifocal behavior in both groups, with the bilateral trifocal group exhibiting better performance for intermediate vision.Conclusion: Both lens combinations were able to provide good near, intermediate and distance vision

  9. Epidemiological evaluation of YAG capsulotomy incidence for posterior capsule opacification in various intraocular lenses in Japanese eyes

    Directory of Open Access Journals (Sweden)

    Nishi Y

    2015-09-01

    Full Text Available Yutaro Nishi,1,2 Tomohiro Ikeda,1 Kayo Nishi,2 Osamu Mimura1 1Department of Ophthalmology, Hyogo College of Medicine, Hyogo, 2Nishi Eye Hospital, Osaka, Japan Background and objective: We investigated the yttrium aluminum garnet (YAG capsulotomy rates in various intraocular lenses (IOLs. Study design/patients and methods: We retrospectively analyzed 23,440 eyes implanted with either MA60BM, MA60AC, VA-60BB, CeeOnEdge, Clariflex, Technis Z9002, SI-40NB, or UV26T IOLs. We calculated the YAG capsulotomy rates at 1, 3, 5, and 10 years post lens implantation. Results: YAG capsulotomy rates at 3 years postimplantation for the eight groups of IOLs were, respectively, 3.7%, 3.9%, 23.7%, 3.4%, 4.5%, 4.7%, 10.4%, and 21.0%. YAG capsulotomy rates at 10 years postimplantation for the MA60BM and SI-40NB IOLs were, respectively, 9.1% and 15% (P<0.05. The average YAG rates for all sharp-edged and round-edged IOLs at 5 years postimplantation were, respectively, 5.2%±0.7% and 25.6%±9.0% (P<0.05. Conclusion: In all studied IOLs, posterior capsule opacification prevention seemed to be associated with the posterior optic sharp-edge design. Round-edged silicone IOLs may also retard posterior capsule opacification formation, though not as much as sharp-edged IOLs. As the follow-up period progressed, round-edged silicone IOLs showed significantly higher YAG rates than sharp-edged IOLs. Keywords: silicone, intraocular lenses, sharp optic edge, chi-square test, implantation surgery, posterior capsule opacification

  10. Management of subluxated capsular bag-fixated intraocular lenses using a capsular anchor

    NARCIS (Netherlands)

    Ton, Yokrat; Naftali, Modi; Lapid Gortzak, Ruth; Assia, Ehud I.

    2016-01-01

    We describe the use of the capsular anchor (AssiAnchor) to manage a subluxated intraocular lens (IOL) in the capsular bag. The anchor comprises 2 prongs that hold the anterior lens capsule and a central rod that is sutured to the scleral wall, enabling centration of the IOL-capsular bag complex. Six

  11. Use of hydroxypropylmethylcellulose 2% for removing adherent silicone oil from silicone intraocular lenses

    OpenAIRE

    Wong , S Chien; Ramkissoon , Yashin D; Lopez , Mauricio; Page , Kristopher; Parkin , Ivan P; Sullivan , Paul M

    2009-01-01

    Abstract Background / aims: To investigate the effect of hydroxypropylmethylcellulose (HPMC) on the physical interaction (contact angle) between silicone oil and a silicone intraocular lens (IOL). Methods: In vitro experiments were performed, to determine the effect of HPMC (0.5%, 1% or 2%), with or without an additional simple mechanical manoeuvre, on the contact angle of silicone oil at the surface of both silicone and acrylic (control) IOLs. A balanced salt solu...

  12. Comparison of glare in YAG-damaged intraocular lenses: injection-molded versus lathe-cut.

    Science.gov (United States)

    Bath, P E; Dang, Y; Martin, W H

    1986-11-01

    A comparative analysis of YAG laser intraocular lens (IOL) damage was undertaken on injection-molded and lathe-cut IOLs. Damage sites were evaluated with polarized light. A consistent positive polarization was observed in the damage sites of lathe-cut IOLs. A consistent negative polarization was observed in the damage sites of injection-molded IOLs. The presence of positive polarization in IOL damage sites may be correlated with increased potential for glare. Results and clinical implications are discussed.

  13. Use of intraocular lenses in children with traumatic cataract in south India

    OpenAIRE

    Eckstein, M.; Vijayalakshmi, P; Killedar, M.; Gilbert, C.; Foster, A.

    1998-01-01

    AIMS—To assess the long term results of intraocular lens (IOL) implantation for traumatic cataract in young children in a developing country.
METHODS—Prospective hospital based study of 52 children (age 2-10 years) undergoing unilateral cataract extraction and IOL insertion for traumatic cataract performed by a single surgeon in south India. Children were reviewed regularly and followed up initially for 3 years.
RESULTS—There were no serious operative complications. Clinically significant pos...

  14. Bilateral implantation of +2.5 D multifocal intraocular lens and contralateral implantation of +2.5 D and +3.0 D multifocal intraocular lenses: Clinical outcomes.

    Science.gov (United States)

    Nuijts, Rudy M M A; Jonker, Soraya M R; Kaufer, Robert A; Lapid-Gortzak, Ruth; Mendicute, Javier; Martinez, Cristina Peris; Schmickler, Stefanie; Kohnen, Thomas

    2016-02-01

    To assess the clinical visual outcomes of bilateral implantation of Restor +2.5 diopter (D) multifocal intraocular lenses (IOLs) and contralateral implantation of a Restor +2.5 D multifocal IOL in the dominant eye and Restor +3.0 D multifocal IOL in the fellow eye. Multicenter study at 8 investigative sites. Prospective randomized parallel-group patient-masked 2-arm study. This study comprised adults requiring bilateral cataract extraction followed by multifocal IOL implantation. The primary endpoint was corrected intermediate visual acuity (CIVA) at 60 cm, and the secondary endpoint was corrected near visual acuity (CNVA) at 40 cm. Both endpoints were measured 3 months after implantation with a noninferiority margin of Δ = 0.1 logMAR. In total, 103 patients completed the study (53 bilateral, 50 contralateral). At 3 months, the mean CIVA at 60 cm was 0.13 logMAR and 0.10 logMAR in the bilateral group and contralateral group, respectively (difference 0.04 logMAR), achieving noninferiority. Noninferiority was not attained for CNVA at 40 cm; mean values at 3 months for bilateral and contralateral implantation were 0.26 logMAR and 0.11 logMAR, respectively (difference 0.15 logMAR). Binocular defocus curves suggested similar performance in distance vision between the 2 groups. Treatment-emergent ocular adverse events rates were similar between the groups. Bilateral implantation of the +2.5 D multifocal IOL resulted in similar distance as contralateral implantation of the +2.5 D multifocal IOL and +3.0 D multifocal IOL for intermediate vision (60 cm), while noninferiority was not achieved for near distances (40 cm). Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  15. Iris-claw intraocular lenses to correct aphakia in the absence of capsule support.

    Science.gov (United States)

    De Silva, Samantha R; Arun, Kikkeri; Anandan, Maghizh; Glover, Nicholas; Patel, Chetan K; Rosen, Paul

    2011-09-01

    To evaluate the indications, postoperative visual efficacy, and complication rate after intraocular implantation of an iris-claw aphakic intraocular lens (IOL). Oxford Eye Hospital, Oxford, United Kingdom. Case series. This chart review comprised eyes with no capsule support that had anterior iris-fixation IOL implantation for aphakia between 2001 and 2009. The study comprised 116 eyes (104 patients). Iris-claw IOLs were inserted during primary lens surgery in 18 eyes (15.5%), during an IOL exchange procedure for dislocated posterior chamber IOLs in 19 eyes (16.4%), and as a secondary procedure in 79 eyes (68.1%). The mean follow-up was 22.4 months (range 3 to 79 months). The final corrected distance visual acuity (CDVA) was 6/12 or better in 68.9% of all eyes and in 47 of 53 eyes (88.7%) with no preoperative comorbidity. Complications included wound leak requiring resuturing in 2.6% of eyes, postoperative intraocular pressure rise in 9.5% of eyes (glaucoma escalation 0.8%), and cystoid macular edema in 7.7% of eyes (0.8% chronic). Iris-claw IOL subluxation occurred in 6.0% of eyes from 5 days to 60 months postoperatively; all the IOLs were repositioned. Corneal decompensation occurred in 1.7% of eyes; 0.8% had retinal detachments. Iris-claw IOL implantation for aphakia gave a good visual outcome and can be used for a wide range of indications. Postoperative complication rates were comparable to, if not better than, those with conventional anterior chamber IOLs. Correct implantation technique is critical in avoiding postoperative IOL subluxation. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  16. Long-term outcomes of ciliary sulcus versus capsular bag fixation of intraocular lenses in children: An ultrasound biomicroscopy study.

    Directory of Open Access Journals (Sweden)

    Yun-E Zhao

    Full Text Available To evaluate the long-term outcomes of ciliary sulcus versus capsular bag fixation of intraocular lenses (IOLs in children after pediatric cataract surgery.IOL was implanted in the ciliary sulcus in 21 eyes of 14 children, and in the capsular bag in 19 eyes of 12 children for the treatment of pediatric cataract in an institutional setting. Ultrasound biomicroscopy (UBM was performed. Main outcome measures included IOL decentration, IOL tilt, anterior chamber depth (ACD, angle-opening distance at 500 μm (AOD500, trabecular-iris angle (TIA, best-corrected visual acuity (BCVA, intraocular pressure (IOP, and incidence of postoperative complications.The mean follow-up period was 6.81 ± 1.82 years. Comparing to the capsular bag fixation group, the ciliary sulcus fixation group had higher vertical IOL decentration, horizontal IOL tilt, and vertical IOL tilt (p = 0.02, 0.01,0.01, respectively, higher incidence of iris-IOL contact and peripheral anterior synechia (p = 0.001, 0.03, respectively, smaller ACD, AOD500, and TIA (p = 0.02, 0.03, 0.04, respectively, higher mean IOP (17.10 ±6.06 mmHg vs.14.15± 4.74 mmHg, p = 0.01, and higher incidence of secondary glaucoma (28.57% vs. 10.53%, p = 0.007.There was no significant difference between the two groups with regard to the BCVA, refractive errors, incidence of myopic shift, nystagmus, strabismus, and visual axis opacity.Ciliary sulcus fixation of IOLs in pediatric eyes may increase IOL malposition and crowding of the anterior segment, and may associate with a higher risk of secondary glaucoma compared to capsular bag fixation of IOLs.

  17. Late dislocation of in-the-bag intraocular lenses in uveitic eyes: An analysis of management and complications

    Directory of Open Access Journals (Sweden)

    Sudha K Ganesh

    2017-01-01

    Full Text Available Aim: An analysis of late in-the-bag dislocation of intraocular lenses (IOL, in uveitic eyes. Setting: Referral uveitis clinic. Design: Retrospective case series. Materials and Methods: All case records of eyes with chronic uveitis that had phacoemulsification with IOL implantation, at a referral uveitis clinic between February 1997 and January 2015 were retrieved and analyzed. Only those eyes with no documented intraoperative complication and no predisposing risks to IOL dislocation, such as pseudoexfoliation, high myopia, trauma, and prior VR surgery were included in this study. Results: A total of 581 eyes with chronic uveitis underwent phacoemulsification with IOL implantation under steroid cover from February 1997 to December 2015. Out of these 581 eyes, 10 patients (11 eyes had experienced late in-the-bag IOL dislocation (1.89%. All 11 eyes had chronic intermediate uveitis. The mean duration from the time of cataract surgery to IOL dislocation was 11.24 years. 5 out of 11 eyes had pars plana vitrectomy (PPV with IOL removal with 4-point sutured scleral fixated IOL. Two out of 11 eyes had PPV with in-the-bag IOL re-fixation. Out of 11, 2 eyes had PPV with IOL removal only. Remaining 2 eyes of 2 patients did not opt for surgery. Out of 11, 8 eyes had improved vision at last follow-up. Conclusions: In-the-bag dislocation of IOL is a rare late complication in uveitic eyes. With tight perioperative inflammatory control, scleral-fixated posterior chamber intraocular lens or IOL re-fixation are good options of restoring vision in these high-risk eyes.

  18. Visual performance after bilateral implantation of 2 new presbyopia-correcting intraocular lenses: Trifocal versus extended range of vision.

    Science.gov (United States)

    Monaco, Gaspare; Gari, Mariangela; Di Censo, Fabio; Poscia, Andrea; Ruggi, Giada; Scialdone, Antonio

    2017-06-01

    To compare the visual outcomes and quality of vision of 2 new diffractive multifocal intraocular lenses (IOLs) with those of a monofocal IOL. Fatebenefratelli e Oftalmico Hospital, Milan, Italy. Prospective case series. Patients had bilateral cataract surgery with implantation of a trifocal IOL (Panoptix), an extended-range-of-vision IOL (Symfony), or a monofocal IOL (SN60WF). Postoperative examinations included assessing distance, intermediate, and near visual acuity; binocular defocus; intraocular and total aberrations; point-spread function (PSF); modulation transfer function (MTF); retinal straylight; and quality-of-vision (QoV) and spectacle-dependence questionnaires. Seventy-six patients (152 eyes) were assessed for study eligibility. Twenty patients (40 eyes) in each arm of the study (60 patients, 120 eyes) completed the outcome assessment. At the 4-month follow-up, the trifocal group had significantly better near visual acuity than the extended-range-of-vision group (P = .005). The defocus curve showed the trifocal IOL had better intermediate/near performance than the extended-range-of-vision IOL and both multifocal IOLs performed better than the monofocal IOL. Intragroup comparison of the total higher-order aberrations, PSF, MTF, and retinal straylight were not statistically different. The QoV questionnaire results showed no differences in dysphotopsia between the multifocal IOL groups; however, the results were significantly higher than in the monofocal IOL group. Both multifocal IOLs seemed to be good options for patients with intermediate-vision requirements, whereas the trifocal IOL might be better for patients with near-vision requirements. The significant perception of visual side effects indicates that patients still must be counseled about these effects before a multifocal IOL is implanted. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. Accuracy of intraocular pressure measurements in dogs using two different tonometers and plano therapeutic soft contact lenses.

    Science.gov (United States)

    Ahn, Jeong-Taek; Jeong, Man-Bok; Park, Young-Woo; Kim, Se-Eun; Ahn, Jae-Sang; Lee, Yes-Ran; Lee, Eui-Ri; Seo, Kangmoon

    2012-03-01

    To compare and evaluate the accuracy of intraocular pressure (IOP) measured through a therapeutic contact lens, using applanation (TonoPen XL(®)) and rebound (TonoVet(®)) tonometers in enucleated dog eyes. A total of 30 enucleated eyes from 15 beagle dogs. To measure accurate IOP, the anterior chamber of each enucleated eye was cannulated with two 26-gauge needles and two polyethylene tubes were connected vertically to an adjustable reservoir bag of normal saline and a pressure transducer. IOP was measured by the TonoPen XL(®) followed by the TonoVet(®) without a contact lens. After a contact lens was applied to the cornea, IOP was re-measured in the same order. Three consecutive IOP measurements were performed using both tonometers. Without the contact lens, the IOP values obtained by both tonometers correlated well according to the regression analysis (TonoVet(®): γ(2) = 0.98, TonoPen XL(®): γ(2) = 0.97, P contact lens was applied to the cornea. Bland-Altman analysis was used to determine the lower and upper limits of agreement (TonoVet(®): -29.7 and +21.1 mmHg, TonoPen XL(®): -3.9 and +3.6 mmHg) between the two devices. This study suggests that the TonoPen XL(®) is a useful tonometer for dogs wearing therapeutic contact lenses, and importantly, contact lenses would not need to be removed prior to IOP measurement. © 2012 American College of Veterinary Ophthalmologists.

  20. Cionni ring and in-the-bag intraocular lens implantation for subluxated lenses: a prospective case series.

    Science.gov (United States)

    Vasavada, Abhay R; Praveen, Mamidipudi R; Vasavada, Viraj A; Yeh, Ru-Yin; Srivastava, Samaresh; Koul, Archana; Trivedi, Rupal H

    2012-06-01

    To report the intraoperative performance and postoperative outcomes of the Cionni-modified capsule tension ring (CTR) implantation in eyes with subluxated lenses. Prospective, observational case series. This study was carried out at Iladevi Cataract & IOL Research Centre, Ahmedabad, India. The study population comprised 41 eyes with subluxated lenses that underwent lens extraction, capsular bag fixation with modified CTR, and in-the-bag single-piece AcrySof intraocular lens (IOL) implantation. Main outcome measures were intraoperative performance and postoperative best-corrected visual acuity (BCVA), IOL centration, and complications. The mean age was 29.46 ± 16.16 years (3-68 years). Mean extent of subluxation was 6.1 ± 1.0 clock hours. Preoperatively, vitreous was detected in the anterior chambers of 5 eyes (12.2%). Two-port anterior chamber vitrectomy was performed in 2 eyes. Mean follow-up was 45.8 ± 2.9 months. Mean preoperative BCVA was 0.66 ± 0.22 logMAR (35 eyes). Mean postoperative BCVA at final follow-up was 0.33 ± 0.21 logMAR (41 eyes) (P IOL decentration was noted and repositioning was required in 2 eyes. Posterior capsule opacification developed in 14 eyes (34.2%); 12 eyes (29.3%) required Nd:YAG capsulotomy. Other complications included cystoid macular edema in 1 eye (2.4%), posterior synechiae in 1 eye (2.4%), and retinal detachment in 1 eye (2.4%). In-the-bag implantation of a Cionni-modified CTR with IOL appears to be a safe option in eyes with subluxated cataract, ensuring a stable IOL with few complications. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Characteristics of the retinal images of the eye optical systems with implanted intraocular lenses

    Science.gov (United States)

    Siedlecki, Damian; Zając, Marek; Nowak, Jerzy

    2007-04-01

    Cataract, or opacity of crystalline lens in the human eye is one of the most frequent reasons of blindness nowadays. Removing the pathologically altered crystalline lens and replacing it with artificial implantable intraocular lens (IOL) is practically the only therapy in this illness. There exist a wide variety of artificial IOL types on the medical market, differing in their material and design (shape). In this paper six exemplary models of IOL's made of PMMA, acrylic and silicone are considered. The retinal image quality is analyzed numerically on the basis of Liou-Brennan eye model with these IOL's inserted. Chromatic aberration as well as polychromatic Point Spread Function and Modulation Transfer Function are calculated as most adequate image quality measures. The calculations made with Zemax TM software show the importance of chromatic aberration correction.

  2. Subluxation of iris-sutured intraocular lenses and results of a closed chamber technique for repositioning after penetrating keratoplasty.

    Science.gov (United States)

    Jabbur, Nada S; Akpek, Esen Karamursel; Stark, Walter J

    2005-05-01

    To describe subluxation of iris-fixated intraocular lenses (IOLs) after penetrating keratoplasty (PK) as a postoperative complication and report the long-term outcomes of a closed-chamber refixation technique used in the management. This was a retrospective, noncomparative interventional case series in which 19 consecutive patient charts with a subluxated iris-fixated IOL after PK were retrospectively reviewed. Fourteen of the patients underwent surgery using a closed-chamber refixation technique. These patients were evaluated for visual outcome and surgical complications associated with the procedure. In 13 patients, postoperative follow-up was available. In all 13 cases, the fixated IOL appeared stable and remained well positioned during a follow-up period of 56 months (range, 6-122). All patients (100%) achieved improved uncorrected visual acuity. The postoperative visual acuity ranged from 20/20 to 20/100 with a mean of 20/40. Vitreous hemorrhage occurred in 1 patient, and an additional patient required a second surgery using the same technique. Both of these patients did well with a final visual acuity of 20/40 and 20/50, respectively. Subluxation of iris-fixated IOL after PK can occur as a postoperative complication. The technique that we herein describe enables secure refixation of subluxated IOLs and yields favorable long-term results.

  3. Influence of material and haptic design on the mechanical stability of intraocular lenses by means of finite-element modeling.

    Science.gov (United States)

    Remón, Laura; Siedlecki, Damian; Cabeza-Gil, Iulen; Calvo, Begoña

    2018-03-01

    Intraocular lenses (IOLs) are used in the cataract treatment for surgical replacement of the opacified crystalline lens. Before being implanted they have to pass the strict quality control to guarantee a good biomechanical stability inside the capsular bag, avoiding the rotation, and to provide a good optical quality. The goal of this study was to investigate the influence of the material and haptic design on the behavior of the IOLs under dynamic compression condition. For this purpose, the strain-stress characteristics of the hydrophobic and hydrophilic materials were estimated experimentally. Next, these data were used as the input for a finite-element model (FEM) to analyze the stability of different IOL haptic designs, according to the procedure described by the ISO standards. Finally, the simulations of the effect of IOL tilt and decentration on the optical performance were performed in an eye model using a ray-tracing software. The results suggest the major importance of the haptic design rather than the material on the postoperative behavior of an IOL. FEM appears to be a powerful tool for numerical studies of the biomechanical properties of IOLs and it allows one to help in the design phase to the manufacturers. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  4. [Comparison of four MICS intraocular lenses regarding their rates of neodymium:YAG laser capsulotomy].

    Science.gov (United States)

    Spyridaki, M; Höh, H

    2010-03-01

    The aim of this study was to evaluate the incidence of posterior capsule opacification up to 50 months following 1.7-mm bimanual MICS-cataract surgery. Bimanual MICS cataract surgery was performed in 197 eyes (135 patients) via two 1.7-mm corneal incisions. Four MICS acrylic foldable IOLs were implanted: AcriSmart 48S-5, n = 54 (Acritec GmbH, Hennigsdorf, now AT.Smart 48S Carl-Zeiss-Meditec, AG, Jena, Germany), ThinLens UltraChoice 1.0, n = 53 (Technomed GmbH, Baesweiler, Germany), AcriFlex 46, n = 41 und AcriFlex 48 CSE, n = 7 (Acrimed GmbH, Berlin, now: Lentis L-303, Oculentis GmbH, Berlin, Germany) and CareFlex, n = 43 (w2o Medizintechnik AG, Bruchsal, Germany). Statistical analysis was performed using the Kaplan-Meier technique. High levels of completeness of follow-up rates were: ThinLens 96%, CareFlex 100%, AcriSmart 93%, AcriFlex 92%. The capsulotomy rate was 43.13% for ThinLens within a mean/max. follow-up period of 801/1131 days, 34.88% for CareFlex (565/872 days), 40% for AcriSmart (988/1506 days) and 15.91% for AcriFlex (728/975 days). By limiting the follow-up period to a comparable maximum of 850 days for all four IOLs, our capsulotomy rates were as follows: ThinLens 33.33%, CareFlex 32.56 %, AcriSmart 20.0% and AcriFlex 11.36%. MICS IOLs have higher capsulotomy rates than hydrophobic acrylic lenses and sharp-edged silicone lenses. In literature comparisons MICS-IOLs do not exceed the variance levels of capsulotomy rates of PMMA, hydrophilic acrylic and silicone lenses without sharp edges. Cases of decentration or luxation of MICS-IOLs following Neodym:YAG laser capsulotomy were not detected. Capsulotomy frequency with the CareFlex was statistically significantly higher in comparison to the AcriSmart (Log Rank Mantel Cox Test, p = 0.007) and AcriFlex (log rank Mantel Cox test, p = 0.002). Capsulotomy rates observed varied for the four MICS-IOL-types tested. The posterior capsule opacification frequency of the two best MICS-IOLs (AcriFlex, Acri

  5. Potential contact and intraocular lenses based on hydrophilic/hydrophobic sulfonated syndiotactic polystyrene membranes

    Directory of Open Access Journals (Sweden)

    Simona Zuppolini

    2017-10-01

    Full Text Available Crystalline films of syndiotactic polystyrene (s-PS, a commercially available thermoplastic polymer, having a highly hydrophilic amorphous phase, were achieved by using a mild solid-state sulfonation procedure. Despite the used mild process conditions, an easy and uniform sulfonation of the phenyl rings of the amorphous phase is obtained. The crystallinity of the polymer was not affect by the sulfonation degree (S, at least at S less than 20%, and the obtained polymer films show the nanoporous crystalline form of s-PS. As widely reported in literature, the nanoporous nature of the polymer crystalline phase gives to these materials the ability to absorb and release organic molecules of appropriate size and polarity. This property, coupled to transparency, makes these materials potentially useful intraocular lens (IOLs and contact lens applications. Sulfonation procedure and sulfonated film samples characterization by using wide-angle X-ray diffraction (WAXD, Fourier-transform infrared (FTIR and ultraviolet-visible (UV-vis spectroscopy techniques and water sorption tests were reported. Furthermore, the biocompatibility study demonstrated no cytotoxicity and appropriate cell interaction properties for the specific applications.

  6. Differences of Longitudinal Chromatic Aberration (LCA) between Eyes with Intraocular Lenses from Different Manufacturers

    Science.gov (United States)

    Nakajima, Masashi; Hiraoka, Takahiro; Yamamoto, Toshiya; Takagi, Seiu; Hirohara, Yoko; Oshika, Tetsuro

    2016-01-01

    Several researchers have studied the longitudinal chromatic aberration (LCA) of eyes implanted with an intraocular lens (IOL). We investigated the LCA of eyes implanted with yellow-colored IOLs from three different manufacturers: Alcon Inc., HOYA Corp., and AMO Inc. The number of subjects was 11, 16, and 16, respectively. The LCA of eyes implanted with SN60WF and SN60AT (Alcon Inc.), and with XY-1 (HOYA Corp.), was the same as that of phakic eyes. The LCA of eyes with ZCB00V (AMO Inc.) was smaller than that of phakic eyes. The LCA of eyes implanted with Alcon’s and HOYA’s IOLs, but not the LCA of eyes implanted with AMO’s IOLs, was positively correlated with the powers of the IOLs. We also performed simulations to verify the impacts of LCA on visual performance for 4-mm pupil diameter; the simulations were a polychromatic modulation transfer function (MTF) and a visual Strehl ratio computed on the basis of an optical transfer function (VSOTF). We concluded that the differences between the LCA of different manufacturers do not affect visual performances when some extent of higher-order aberration (HOA) exists. The smaller HOA of AMO IOLs may enhance visual performance. PMID:27258141

  7. Reading ability with pseudophakic monovision and with refractive multifocal intraocular lenses: comparative study.

    Science.gov (United States)

    Ito, Misae; Shimizu, Kimiya

    2009-09-01

    To the compare the reading ability after bilateral cataract surgery in patients who had pseudophakic monovision achieved by monofocal intraocular lens (IOL) implantation and patients who had refractive multifocal IOL implantation. Department of Ophthalmology, Kitasato University Hospital, Kanagawa, Japan. This study evaluated patients who had bilateral cataract surgery using the monovision method with monofocal IOL implantation to correct presbyopia (monovision group) or who had bilateral cataract surgery with refractive multifocal IOL implantation (multifocal group). In the monovision group, the dominant eye was corrected for distance vision and the nondominant eye for near vision. The maximum reading speed, critical character size, and reading acuity were measured binocularly without refractive correction using MNREAD-J acuity charts. The monovision group comprised 38 patients and the multifocal group, 22 patients. The mean maximum reading speed was 350.5 characters per minute (cpm) +/- 62.3 (SD) in the monovision group and 355.0 +/- 53.3 cpm in the multifocal group; the difference was not statistically significant. The mean critical character size was 0.24 +/- 0.12 logMAR and 0.40 +/- 0.16 logMAR, respectively (P<.05). The mean reading acuity was 0.05 +/- 0.12 logMAR and 0.19 +/- 0.11 logMAR, respectively (P<.01). The monovision group had better critical character size and reading acuity results. The monovision method group had better reading ability; however, careful patient selection is essential.

  8. Scleral Fixation of Posteriorly Dislocated Intraocular Lenses by 23-Gauge Vitrectomy without Anterior Segment Approach

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    Jeroni Nadal

    2015-01-01

    Full Text Available Background. To evaluate visual outcomes, corneal changes, intraocular lens (IOL stability, and complications after repositioning posteriorly dislocated IOLs and sulcus fixation with polyester sutures. Design. Prospective consecutive case series. Setting. Institut Universitari Barraquer. Participants. 25 eyes of 25 patients with posteriorly dislocated IOL. Methods. The patients underwent 23-gauge vitrectomy via the sulcus to rescue dislocated IOLs and fix them to the scleral wall with a previously looped nonabsorbable polyester suture. Main Outcome Measures. Best corrected visual acuity (BCVA LogMAR, corneal astigmatism, endothelial cell count, IOL stability, and postoperative complications. Results. Mean follow-up time was 18.8 ± 10.9 months. Mean surgery time was 33 ± 2 minutes. Mean BCVA improved from 0.30 ± 0.48 before surgery to 0.18 ± 0.60 (p=0.015 at 1 month, which persisted to 12 months (0.18 ± 0.60. Neither corneal astigmatism nor endothelial cell count showed alterations 1 year after surgery. Complications included IOL subluxation in 1 eye (4%, vitreous hemorrhage in 2 eyes (8%, transient hypotony in 2 eyes (8%, and cystic macular edema in 1 eye (4%. No patients presented retinal detachment. Conclusion. This surgical technique proved successful in the management of dislocated IOL. Functional results were good and the complications were easily resolved.

  9. [Subluxation of hydrophilic acrylate intraocular lenses due to massive capsular fibrosis].

    Science.gov (United States)

    Kramer, S; Schröder, A C; Brückner, K; Jonescu-Cuypers, C; Seitz, B

    2010-05-01

    Compared with other biomaterials, hydrophilic acrylate provides better uveal biocompatibility, lower adhesion rates of bacteria and silicone oil, and less glare. Because of reduced capsular biocompatibility, increased fibrosis may initiate dislocation of the intraocular lens (IOL). In six eyes of four patients, enhanced fibroses led to IOL dislocation, leading to an IOL exchange an average of 40 weeks after implantation of the same hydrophilic acrylate lens type. Predisposing factors were found in 90% of all reported cases of IOL dislocation in the literature, but not in the cases described here. The lens type that was implanted was unable to adapt to the massive fibrosis induced by its hydrophilic biomaterial. The pattern of lens opacification should receive attention when one is choosing an IOL type. Eyes showing pseudoexfoliation syndrome as well as post-uveitis eyes might require a hydrophilic IOL for less cellular reaction, whereas a posterior subcapsular cataract might need a hydrophobic IOL to prevent a massive capsular fibrosis. In the case of increased capsular contraction, unreflected YAG laser capsulotomy may result in IOL subluxation when the lens design cannot handle capsule shrinkage, as demonstrated here.

  10. Scleral Fixation of Posteriorly Dislocated Intraocular Lenses by 23-Gauge Vitrectomy without Anterior Segment Approach.

    Science.gov (United States)

    Nadal, Jeroni; Kudsieh, Bachar; Casaroli-Marano, Ricardo P

    2015-01-01

    Background. To evaluate visual outcomes, corneal changes, intraocular lens (IOL) stability, and complications after repositioning posteriorly dislocated IOLs and sulcus fixation with polyester sutures. Design. Prospective consecutive case series. Setting. Institut Universitari Barraquer. Participants. 25 eyes of 25 patients with posteriorly dislocated IOL. Methods. The patients underwent 23-gauge vitrectomy via the sulcus to rescue dislocated IOLs and fix them to the scleral wall with a previously looped nonabsorbable polyester suture. Main Outcome Measures. Best corrected visual acuity (BCVA) LogMAR, corneal astigmatism, endothelial cell count, IOL stability, and postoperative complications. Results. Mean follow-up time was 18.8 ± 10.9 months. Mean surgery time was 33 ± 2 minutes. Mean BCVA improved from 0.30 ± 0.48 before surgery to 0.18 ± 0.60 (p = 0.015) at 1 month, which persisted to 12 months (0.18 ± 0.60). Neither corneal astigmatism nor endothelial cell count showed alterations 1 year after surgery. Complications included IOL subluxation in 1 eye (4%), vitreous hemorrhage in 2 eyes (8%), transient hypotony in 2 eyes (8%), and cystic macular edema in 1 eye (4%). No patients presented retinal detachment. Conclusion. This surgical technique proved successful in the management of dislocated IOL. Functional results were good and the complications were easily resolved.

  11. Methods of fixation of intraocular lenses according to the anatomical structures in trauma eyes.

    Science.gov (United States)

    Fiorentzis, Miltiadis; Viestenz, Anja; Heichel, Jens; Seitz, Berthold; Hammer, Thomas; Viestenz, Arne

    2018-01-01

    Ocular trauma can lead to severe visual impairment and morbidity, depending on the anatomical structures affected. The main causes of ocular trauma include foreign bodies, impact by an object, falls, and chemicals. Most ocular traumas occur in children or young male adults. A meticulous slit lamp examination is crucial for assessing all anatomical structures. Trauma to the crystalline lens can result in dislocation, an intralenticular foreign body, cataract, fragmentation, and capsular breach. An intraocular lens (IOL) can endure subluxation or luxation under the conjunctiva, into the anterior chamber or the vitreous, or can be extruded. The surgical approach depends on the condition and morphology of the lens and the anatomical structures surrounding it. If there is capsular bag support, a secondary IOL can be placed in the sulcus using remnants of the damaged capsule. If there is no capsular bag support, a secondary IOL can be fixated to the anterior chamber angle, to the iris, or to the sclera. A detailed history of injury cannot always be obtained in trauma settings. Proper education, supervision, and certified safety eye protectors could prevent up to 90% of ocular injuries. Lens trauma can be treated with various surgical procedures and fixation techniques, which nevertheless require advanced surgical skills owing to the fine anatomical structure of the anterior segment. A careful surgical strategy should be established for a globe reconstruction after trauma with secondary lens implantation. Clin. Anat. 31:6-15, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Aspherical supernovae

    International Nuclear Information System (INIS)

    Kasen, Daniel Nathan

    2004-01-01

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3) And

  13. Correlating optical bench performance with clinical defocus curves in varifocal and trifocal intraocular lenses.

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    Plaza-Puche, Ana B; Alió, Jorge L; MacRae, Scott; Zheleznyak, Len; Sala, Esperanza; Yoon, Geunyoung

    2015-05-01

    To investigate the correlations existing between a trifocal intraocular lens (IOL) and a varifocal IOL using the "ex vivo" optical bench through-focus image quality analysis and the clinical visual performance in real patients by study of the defocus curves. This prospective, consecutive, nonrandomized, comparative study included a total of 64 eyes of 42 patients. Three groups of eyes were differentiated according to the IOL implanted: 22 eyes implanted with the varifocal Lentis Mplus LS-313 IOL (Oculentis GmbH, Berlin, Germany); 22 eyes implanted with the trifocal FineVision IOL (Physiol, Liege, Belgium), and 20 eyes implanted with the monofocal Acrysof SA60AT IOL (Alcon Laboratories, Inc., Fort Worth, TX). Visual outcomes and defocus curve were evaluated postoperatively. Optical bench through-focus performance was quantified by computing an image quality metric and the cross-correlation coefficient between an unaberrated reference image and captured retinal images from a model eye with a 3.0-mm artificial pupil. Statistically significant differences among defocus curves of different IOLs were detected for the levels of defocus from -4.00 to -1.00 diopters (D) (P < .01). Significant correlations were found between the optical bench image quality metric results and logMAR visual acuity scale in all groups (Lentis Mplus group: r = -0.97, P < .01; FineVision group: r = -0.82, P < .01; Acrys of group: r = -0.99, P < .01). Linear predicting models were obtained. Significant correlations were found between logMAR visual acuity and image quality metric for the multifocal and monofocal IOLs analyzed. This finding enables surgeons to predict visual outcomes from the optical bench analysis. Copyright 2015, SLACK Incorporated.

  14. Pigment dispersion and Artisan phakic intraocular lenses: crystalline lens rise as a safety criterion.

    Science.gov (United States)

    Baïkoff, Georges; Bourgeon, Grégoire; Jodai, Horacio Jitsuo; Fontaine, Aline; Lellis, Fernando Viera; Trinquet, Laure

    2005-04-01

    To validate the theory that crystalline lens rise can be used as a safety criterion to prevent pigment dispersion in eyes with an Artisan phakic intraocular lens (IOL) (Ophtec BV). Monticelli Clinic, Marseilles, France. A comparative analysis of crystalline lens rise in 9 eyes with pigment dispersion and 78 eyes without dispersion was performed. All eyes had previous implantation of an Artisan IOL. Anterior segment imaging was done using an anterior chamber optical coherence tomography (AC OCT) prototype. Crystalline lens rise was defined by the distance between the anterior pole of the crystalline lens and the horizontal plane joining the opposite iridocorneal recesses. The study confirmed that crystalline lens rise can be considered a safety criterion for implantation of Artisan-type phakic IOLs. The higher the crystalline lens rise, the greater the risk for developing pigment dispersion in the area of the pupil. This complication occurred more frequently in hyperopic eyes than in myopic eyes. Results indicate there is little or no risk for pigment dispersion if the rise is less than 600 microm; 67% of eyes with a rise of 600 microm or more developed pupillary pigment dispersion. In some cases in which the IOL was loosely fixated, there was no traction on the iris root and dispersion was prevented or delayed. Crystalline lens rise should be considered a new safety criterion for Artisan phakic IOL implantation and should also be applied to other types of phakic IOLs. The distance remaining between the crystalline lens rise and a 600 microm theoretical safety level allows one to calculate how long the IOL can safely remain in the eye.

  15. Trifocal intraocular lenses: a comparison of the visual performance and quality of vision provided by two different lens designs

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    Gundersen KG

    2017-06-01

    Full Text Available Kjell G Gundersen,1 Rick Potvin2 1IFocus Øyeklinikk AS, Haugesund, Norway; 2Science in Vision, Akron, NY, USA Purpose: To compare two different diffractive trifocal intraocular lens (IOL designs, evaluating longer-term refractive outcomes, visual acuity (VA at various distances, low contrast VA and quality of vision.Patients and methods: Patients with binocularly implanted trifocal IOLs of two different designs (FineVision [FV] and Panoptix [PX] were evaluated 6 months to 2 years after surgery. Best distance-corrected and uncorrected VA were tested at distance (4 m, intermediate (80 and 60 cm and near (40 cm. A binocular defocus curve was collected with the subject’s best distance correction in place. The preferred reading distance was determined along with the VA at that distance. Low contrast VA at distance was also measured. Quality of vision was measured with the National Eye Institute Visual Function Questionnaire near subset and the Quality of Vision questionnaire.Results: Thirty subjects in each group were successfully recruited. The binocular defocus curves differed only at vergences of −1.0 D (FV better, P=0.02, −1.5 and −2.00 D (PX better, P<0.01 for both. Best distance-corrected and uncorrected binocular vision were significantly better for the PX lens at 60 cm (P<0.01 with no significant differences at other distances. The preferred reading distance was between 42 and 43 cm for both lenses, with the VA at the preferred reading distance slightly better with the PX lens (P=0.04. There were no statistically significant differences by lens for low contrast VA (P=0.1 or for quality of vision measures (P>0.3.Conclusion: Both trifocal lenses provided excellent distance, intermediate and near vision, but several measures indicated that the PX lens provided better intermediate vision at 60 cm. This may be important to users of tablets and other handheld devices. Quality of vision appeared similar between the two lens designs

  16. Outcomes of presbyopia-correcting intraocular lenses after laser in situ keratomileusis.

    Science.gov (United States)

    Chow, Sharon S W; Chan, Tommy C Y; Ng, Alex L K; Kwok, Alvin K H

    2018-03-28

    Laser in situ keratomileusis (LASIK) is the most common refractive surgery in young patients, which aims at providing a clear distance vision without the use of spectacles. With time, these patients develop symptomatic cataract, which affects activities of daily living, and to improve visual acuity, intraocular lens (IOL) implantation can be considered. In post-myopic LASIK patients, to allow continuation of spectacle independence, the implantation of presbyopia-correcting IOLs is a suitable option. The purpose of this retrospective case series is to report the visual outcome and quality in post-myopic LASIK eyes after the implantation of AT LISA tri839MP IOL. Twenty eyes of 13 patients with history of myopic LASIK within 20 years underwent phacoemulsification by one single surgeon. All eyes were implanted with AT LISA tri839PMP IOL, and their outcomes were evaluated at 6 months postoperation. The mean postoperative uncorrected distance visual acuity (VA) is 0.28 ± 0.29, while the corrected distance VA is 0.06 ± 0.14. The mean postoperative uncorrected near VA is 0.02 ± 0.05, while the corrected near VA is 0.01 ± 0.02. The mean postoperative manifest refraction spherical equivalent (SE) is - 0.92 ± 0.76D. There is a statistically significant difference between the preoperative and postoperative refraction (p = 0.02), which shows a postoperative myopic shift. There is also a statistically significant difference between the mean targeted SE and postoperative manifest refraction SE (p = 0.00). Only one out of 20 eyes (5%) reported halo and glare symptoms. Ten out of 20 eyes (50%) are able to achieve spectacles independence. In conclusion, in post-myopic LASIK eyes, AT LISA tri839MP provides a good visual outcome at both near and distance, but is more predictable at near than at distance. There is a myopic shift in the postoperative SE. Visual quality is satisfactory and has not been exacerbated. Most patients can remain to be

  17. Surgical Indications and Clinical Results of Patients with Exchanged Intraocular Lenses in a Tertiary Eye Hospital.

    Science.gov (United States)

    Kavuncu, Sevim; Omay, Aslıhan Esra; Tırhış, Mehmet Hakan; Yılmazbaş, Pelin

    2016-08-01

    To evaluate the demographics, surgical indications and clinical results of patients with repositioned or explanted intraocular lens (IOL) in a tertiary referral eye hospital. Forty-eight eyes of 48 patients that underwent surgery to exchange or reposition the IOL at Ulucanlar Eye Training and Research Hospital between 2009 and 2013 were included in the study. Medical records of patients were evaluated for surgical indications, time elapsed since initial operation, preoperative and postoperative best corrected distance visual acuity and the presence of ocular disease. The mean age of the 31 male and 17 female patients was 64.91±14.26 years. Median time between the initial and final operations was 36.0 months. Pseudoexfoliation syndrome (PEX) was present in 25% of the patients. There was history of previous vitreoretinal surgery in 18.8% of patients, ocular trauma in 6.3%, high myopia and refractive surgery in 4% of patients. In the first operation the IOL was implanted in the sulcus in 50%, in the bag in 27.1%, and in the anterior chamber in 20.8%; following the final surgery the IOL was in the sulcus in 27.1%, in the anterior chamber in 22.9%, and fixated to the sclera in 10.4% of the patients, while the remaining 29.1% remained aphakic. Indication for the secondary surgery was IOL dislocation in 58%, corneal decompensation in 20.8% and IOL degeneration in 6.3%. In the final surgery, IOL was exchanged in 54.2% of the cases, removed in 31.3% of cases, and repositioned in 14.6%. Visual acuity improved by 1-3 lines in 52.3% and remained stable in 13.6% of the patients postoperatively. IOL exchange may be necessary at any time following cataract surgery due to surgical complications, IOL dislocation, biometric measurement errors and corneal decompensation. Factors such as vitreoretinal surgery and the existence of PEX increase the risk of IOL exchange surgery.

  18. Surgical Indications and Clinical Results of Patients with Exchanged Intraocular Lenses in a Tertiary Eye Hospital

    Directory of Open Access Journals (Sweden)

    Sevim Kavuncu

    2016-08-01

    Full Text Available Objectives: To evaluate the demographics, surgical indications and clinical results of patients with repositioned or explanted intraocular lens (IOL in a tertiary referral eye hospital. Materials and Methods: Forty-eight eyes of 48 patients that underwent surgery to exchange or reposition the IOL at Ulucanlar Eye Training and Research Hospital between 2009 and 2013 were included in the study. Medical records of patients were evaluated for surgical indications, time elapsed since initial operation, preoperative and postoperative best corrected distance visual acuity and the presence of ocular disease. Results: The mean age of the 31 male and 17 female patients was 64.91±14.26 years. Median time between the initial and final operations was 36.0 months. Pseudoexfoliation syndrome (PEX was present in 25% of the patients. There was history of previous vitreoretinal surgery in 18.8% of patients, ocular trauma in 6.3%, high myopia and refractive surgery in 4% of patients. In the first operation the IOL was implanted in the sulcus in 50%, in the bag in 27.1%, and in the anterior chamber in 20.8%; following the final surgery the IOL was in the sulcus in 27.1%, in the anterior chamber in 22.9%, and fixated to the sclera in 10.4% of the patients, while the remaining 29.1% remained aphakic. Indication for the secondary surgery was IOL dislocation in 58%, corneal decompensation in 20.8% and IOL degeneration in 6.3%. In the final surgery, IOL was exchanged in 54.2% of the cases, removed in 31.3% of cases, and repositioned in 14.6%. Visual acuity improved by 1-3 lines in 52.3% and remained stable in 13.6% of the patients postoperatively. Conclusion: IOL exchange may be necessary at any time following cataract surgery due to surgical complications, IOL dislocation, biometric measurement errors and corneal decompensation. Factors such as vitreoretinal surgery and the existence of PEX increase the risk of IOL exchange surgery.

  19. Combined pars plana lensectomy-vitrectomy with open-loop flexible anterior chamber intraocular lens (AC IOL) implantation for subluxated lenses.

    Science.gov (United States)

    Kazemi, S; Wirostko, W J; Sinha, S; Mieler, W F; Koenig, S B; Sheth, B P

    2000-01-01

    To review our experience with combined pars plana lensectomy-vitrectomy and open-loop flexible anterior chamber intraocular lens (AC IOL) implantation for managing subluxated crystalline lenses. Retrospective review of 36 consecutive eyes (28 patients), all of which had subluxated crystalline lenses, managed by pars plana lensectomy-vitrectomy with insertion of an open-loop flexible AC IOL. The study was performed at the Medical College of Wisconsin, Milwaukee, over an 8-year period. An average preoperative visual acuity of 20/163 (range, 20/25 to hand motions) improved to 20/36 (range, 20/20 to 4/200) with surgery after a mean follow-up of 14 months (range, 1 to 59 months) (P IOL implantation appears to be an excellent technique for managing subluxated crystalline lenses. It is associated with a significant improvement in visual acuity (P subluxated lens through a limbal wound. Additionally, use of an AC IOL offers a simplified alternative to placement of a ciliary sulcus sutured posterior chamber intraocular lens (PC IOL).

  20. Efficacy and safety of multifocal intraocular lenses following cataract and refractive lens exchange: Metaanalysis of peer-reviewed publications.

    Science.gov (United States)

    Rosen, Emanuel; Alió, Jorge L; Dick, H Burkhard; Dell, Steven; Slade, Stephen

    2016-02-01

    We performed a metaanaysis of peer-reviewed studies involving implantation of a multifocal intraocular lens (IOL) in presbyopic patients with cataract or having refractive lens exchange (RLE). Previous reviews have considered the use of multifocal IOLs after cataract surgery but not after RLE, whereas greater insight might be gained from examining the full range of studies. Selected studies were examined to collate outcomes with monocular and binocular uncorrected distance, intermediate, and near visual acuity; spectacle independence; contrast sensitivity; visual symptoms; adverse events; and patient satisfaction. In 8797 eyes, the mean postoperative monocular uncorrected distance visual acuity (UDVA) was 0.05 logMAR ± 0.006 (SD) (Snellen equivalent 20/20(-3)). In 6334 patients, the mean binocular UDVA was 0.04 ± 0.00 logMAR (Snellen equivalent 20/20(-2)), with a mean spectacle independence of 80.1%. Monocular mean UDVA did not differ significantly between those who had a cataract procedure and those who had an RLE procedure. Neural adaptation to multifocality may vary among patients. Dr. Alió is a clinical research investigator for Hanita Lenses, Carl Zeiss Meditec AG, Topcon Medical Systems, Inc., Oculentis GmbH, and Akkolens International BV. Dr. Dell is a consultant to Bausch & Lomb and Abbott Medical Optics, Inc. Dr. Slade is a consultant to Alcon Surgical, Inc., Carl Zeiss Meditec AG, and Bausch & Lomb. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  1. Simulation of the Effect of Different Presbyopia-Correcting Intraocular Lenses With Eyes With Previous Laser Refractive Surgery.

    Science.gov (United States)

    Camps, Vicente J; Miret, Juan J; García, Celia; Tolosa, Angel; Piñero, David P

    2018-04-01

    To simulate the optical performance of three presbyopia-correcting intraocular lenses (IOLs) implanted in eyes with previous laser refractive surgery. A simulation of the through-focus modulation transfer function (MTF) was performed for three presbyopia-correcting IOLs (Mplus, Oculentis GmbH, Berlin, Germany; Symfony, Johnson & Johnson Vision, Santa Ana, CA; and Mini Well, SIFI S.p.A., Lavinaio, Italy) in one eye with previous myopic LASIK and another with hyperopic LASIK. Real topographic data and the wavefront aberration profile of each IOL obtained with a Hartmann-Shack sensor were used. In the eye with myopic LASIK, all IOLs lost optical quality at near and intermediate distances for 4- and 4.7-mm pupil size. For 3-mm pupil size, the Mini Well IOL showed the best intermediate and near MTF and maintained the far focus independently of the pupil. In the eye with hyperopic LASIK, the Mini Well IOL showed an intermediate, distance, and -4.00-diopter (D) foci for all pupils. The Symfony IOL showed a depth of focus at far and intermediate distance for 3-mm and a focus at -2.50 D in the rest. The Mplus showed a focus of -4.50 and -3.00 D for the 3- and 4-mm pupil, respectively. The Mini Well and Symfony IOLs seem to work better than the Mplus IOL in eyes with previous myopic LASIK. With previous hyperopic LASIK, the Mini Well IOL seems to be able to provide acceptable near, intermediate, and far foci for all pupil sizes. These findings should be confirmed in future clinical studies. [J Refract Surg. 2018;34(4):222-227.]. Copyright 2018, SLACK Incorporated.

  2. Comparison of clinical outcomes between limbal relaxing incisions and toric intraocular lenses in eyes with astigmatic corneas

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    Giuliano de Oliveira Freitas

    2014-01-01

    Full Text Available Objective: To compare refractive and vectorial outcomes of limbal relaxing incisions (LRI versus toric intraocular lenses (IOL in the treatment of preexisting corneal astigmatism at the time of phacoemulsification. Methods: This longitudinal observational case series assessed 62 eyes of 31 consecutive cataract patients with preoperative corneal astigmatism between 0.75 and 2.50 diopters in both eyes. Patients were randomly assorted in two groups: one assigned to receive AcrySof Toric™ IOL in both eyes, and another one assigned to have AcrySof Natural™ IOL associated with LRI, also in both eyes. All patients were re-evaluated, postoperatively, at 1, 3 and 6 months, when refractive astigmatism analysis was performed using vectorial methods proposed by Thibos. Variability of outcomes within each group and between groups were assessed and compared. Results: Manifest refractive cylinder, in diopters (D, as means ± standard deviation, in the LRI group for 1-month, 3-month and 6-month re-evalutions were respectively -0.66 ± 0.30; -0.70 ± 0.21 and -0.74 ± 0.26 when compared to -0.58 ± 0.24; -0.63 ± 0.20, and -0.62 ± 0.17 in the toric IOL group. (p value ≥ 0.06. Vectorial analysis evidenced greater astigmatism reduction in the toric IOL group in the 6th postoperative month, when postoperative mean astigmatic power vector was 0.31 D, when compared to 0.37 D in the LRI group (p value = 0.00. Conclusions: A trend of slightly better refractive outcomes favoring toric IOL group was seen, although such a trend was not statistically significant. Vectorial analysis, however, suggests that the use of toric IOL may constitute a more advantageous approach in the treatment of pre-existing corneal astigmatism, simultaneously with phacoemulsification.

  3. A stepwise approach for the management of capsular contraction syndrome in hinge-based accommodative intraocular lenses.

    Science.gov (United States)

    Page, Timothy P; Whitman, Jeffrey

    2016-01-01

    The aims of this study are to define the various stages of capsular contraction syndrome (CCS) and its effect on refractive error with hinge-based accommodating intraocular lenses (IOLs) and to describe a systematic approach for the management of the different stages of CCS. Hinge-based accommodative IOLs function via flexible hinges that vault the optic forward during accommodation. However, it is the flexibility of the IOL that makes it prone to deformation in the event of CCS. The signs of CCS are identified and described as posterior capsular striae, fibrotic bands across the anterior or posterior capsule, and capsule opacification. Various degrees of CCS may affect hinge-based accommodating IOLs in a spectrum from subtle changes in IOL appearance to significant increases in refractive error and loss of uncorrected visual acuity. The signs of CCS and its effect on IOL position and the resulting changes in refractive error are matched to appropriate treatment plans. A surgeon can avoid CCS and manage the condition if familiar with the early signs of CCS. If CCS is identified, yttrium-aluminum-garnet laser capsulotomy should be considered. If moderate CCS occurs, it may be effectively treated with insertion of a capsular tension ring. If CCS is allowed to progress to advanced stages, an IOL exchange may be necessary. Surgeons should be familiar with the stages of CCS and subsequent interventions. The steps outlined in this article help to guide surgeons in the prevention and management of CCS with hinge-based accommodative IOLs in order to provide improved refractive outcomes for patients.

  4. A stepwise approach for the management of capsular contraction syndrome in hinge-based accommodative intraocular lenses

    Directory of Open Access Journals (Sweden)

    Page TP

    2016-06-01

    Full Text Available Timothy P Page,1 Jeffrey Whitman2 1Department of Ophthalmology, Oakland University William Beaumont School of Medicine, Royal Oak, MI, 2Key-Whitman Eye Center, Dallas, TX, USA Purpose: The aims of this study are to define the various stages of capsular contraction syndrome (CCS and its effect on refractive error with hinge-based accommodating intraocular lenses (IOLs and to describe a systematic approach for the management of the different stages of CCS. Methods: Hinge-based accommodative IOLs function via flexible hinges that vault the optic forward during accommodation. However, it is the flexibility of the IOL that makes it prone to deformation in the event of CCS. The signs of CCS are identified and described as posterior capsular striae, fibrotic bands across the anterior or posterior capsule, and capsule opacification. Various degrees of CCS may affect hinge-based accommodating IOLs in a spectrum from subtle changes in IOL appearance to significant increases in refractive error and loss of uncorrected visual acuity. The signs of CCS and its effect on IOL position and the resulting changes in refractive error are matched to appropriate treatment plans. Results: A surgeon can avoid CCS and manage the condition if familiar with the early signs of CCS. If CCS is identified, yttrium–aluminum–garnet laser capsulotomy should be considered. If moderate CCS occurs, it may be effectively treated with insertion of a capsular tension ring. If CCS is allowed to progress to advanced stages, an IOL exchange may be necessary. Conclusion: Surgeons should be familiar with the stages of CCS and subsequent interventions. The steps outlined in this article help to guide surgeons in the prevention and management of CCS with hinge-based accommodative IOLs in order to provide improved refractive outcomes for patients. Keywords: z-syndrome, pseudophakic tilt, IOL subluxation, CTR, capsular tension ring, capsular fibrosis

  5. Light-distortion analysis as a possible indicator of visual quality after refractive lens exchange with diffractive multifocal intraocular lenses.

    Science.gov (United States)

    Brito, Pedro; Salgado-Borges, José; Neves, Helena; Gonzalez-Meijome, José; Monteiro, Manuel

    2015-03-01

    To study the perception of light distortion after refractive lens exchange (RLE) with diffractive multifocal intraocular lenses (IOLs). Clínica Oftalmológica das Antas, Porto, Portugal. Retrospective comparative study. Refractive lens exchange was performed with implantation of an AT Lisa 839M (trifocal) or 909MP (bifocal toric) IOL, the latter if corneal astigmatism was more than 0.75 diopter (D). The postoperative visual and refractive outcomes were evaluated. A prototype light-distortion analyzer was used to quantify the postoperative light-distortion indices. A control group of eyes in which a Tecnis ZCB00 1-piece monofocal IOL was implanted had the same examinations. A trifocal or bifocal toric IOL was implanted in 66 eyes. The control IOL was implanted in 18 eyes. All 3 groups obtained a significant improvement in uncorrected distance visual acuity (UDVA) (P refractive cylinder was less than 1.00 D in 86.7% of cases with the toric IOL. The mean light-distortion index was significantly higher in the multifocal IOL groups than in the monofocal group (P light-distortion index and CDVA. The multifocal IOLs provided excellent UDVA and functional UNVA despite increased light-distortion indices. The light-distortion analyzer reliably quantified a subjective component of vision distinct from visual acuity; it may become a useful adjunct in the evaluation of visual quality obtained with multifocal IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  6. Acuidade visual em implantes bilaterais de lentes intra-oculares monofocais e multifocais Visual acuity of bilateral implants of monofocal and multifocal intraocular lenses

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    Leonardo Akaishi

    2003-01-01

    Full Text Available OBJETIVO: Comparar a acuidade visual de longe e perto de pacientes submetidos à facoemulsificação binocular não simultânea com implante de lentes multifocais ou monofocais. MÉTODOS: Foram selecionados 20 pacientes com lentes multifocais bilaterais e outros 20 pacientes com lentes monofocais também bilaterais, com acuidade visual sem correção melhor ou igual a 0,63 (20/30, medidos separadamente, nos três primeiros meses de pós-operatório. Foi medida a acuidade visual para longe e perto com e sem correção e testes de sensibilidade ao contraste e ofuscamento. RESULTADOS: A acuidade visual sem correção para longe no grupo das monofocais teve média de 0,82 (DP± 0,16 e no grupo das multifocais, 0,94 (DP±0,12, valor de p 0,001. Os dois grupos de lentes tiveram visão com correção para longe igual a 1. No grupo das multifocais, 75% tiveram J1 e 100% tiveram J3 ou melhor sem correção. No grupo das lentes monofocais, 10% tiveram J1 e 70% tiveram J3 ou melhor sem correção. Não houve diferença significante na avaliação com o teste de sensibilidade ao contraste entre os grupos pesquisados. No teste de ofuscamento, os dois grupos tiveram redução da visão, que foi mais acentuada no grupo dos pacientes com lentes multifocais. CONCLUSÃO: A acuidade visual para longe com correção nos pacientes com implante multifocal foi semelhante a dos pacientes com implantes monofocais, embora a acuidade visual para perto no grupo em que foi implantado lente multifocal foi bastante superior ao grupo da lente monofocal. A sensibilidade ao contraste manteve-se semelhante nos dois grupos, já o ofuscamento ("glare test" no grupo multifocal foi maior que no grupo monofocal.PURPOSE: To compare distant and near visual acuity between patients submitted to bilateral nonsimultaneous facoemulsification and implantation of multifocal or monofocal intraocular lenses (IOL. METHODS: Twenty patients with bilateral multifocal IOL and 20 patients with

  7. Piggyback intraocular lens implantation to correct pseudophakic refractive error after segmental multifocal intraocular lens implantation.

    Science.gov (United States)

    Venter, Jan A; Oberholster, Andre; Schallhorn, Steven C; Pelouskova, Martina

    2014-04-01

    To evaluate refractive and visual outcomes of secondary piggyback intraocular lens implantation in patients diagnosed as having residual ametropia following segmental multifocal lens implantation. Data of 80 pseudophakic eyes with ametropia that underwent Sulcoflex aspheric 653L intraocular lens implantation (Rayner Intraocular Lenses Ltd., East Sussex, United Kingdom) to correct residual refractive error were analyzed. All eyes previously had in-the-bag zonal refractive multifocal intraocular lens implantation (Lentis Mplus MF30, models LS-312 and LS-313; Oculentis GmbH, Berlin, Germany) and required residual refractive error correction. Outcome measurements included uncorrected distance visual acuity, corrected distance visual acuity, uncorrected near visual acuity, distance-corrected near visual acuity, manifest refraction, and complications. One-year data are presented in this study. The mean spherical equivalent ranged from -1.75 to +3.25 diopters (D) preoperatively (mean: +0.58 ± 1.15 D) and reduced to -1.25 to +0.50 D (mean: -0.14 ± 0.28 D; P < .01). Postoperatively, 93.8% of eyes were within ±0.50 D and 98.8% were within ±1.00 D of emmetropia. The mean uncorrected distance visual acuity improved significantly from 0.28 ± 0.16 to 0.01 ± 0.10 logMAR and 78.8% of eyes achieved 6/6 (Snellen 20/20) or better postoperatively. The mean uncorrected near visual acuity changed from 0.43 ± 0.28 to 0.19 ± 0.15 logMAR. There was no significant change in corrected distance visual acuity or distance-corrected near visual acuity. No serious intraoperative or postoperative complications requiring secondary intraocular lens removal occurred. Sulcoflex lenses proved to be a predictable and safe option for correcting residual refractive error in patients diagnosed as having pseudophakia. Copyright 2014, SLACK Incorporated.

  8. The influence of lens power and center thickness on the intraocular pressure measured through soft lenses: a comparison of two noncontact tonometers.

    Science.gov (United States)

    Ogbuehi, Kelechi C

    2012-06-01

    To quantify the influence of soft contact lens power and thickness on the intraocular pressure (IOP). Thirty-nine young, healthy adult volunteers completed this study. One eye of each subject was randomly assigned either a +6D or a -6D high water content daily disposable lens. The other eye was fitted with the second lens. Triplicate measurements of IOP were taken before, during, and after contact lens wear. Each time, IOP was assessed in a randomized order with two noncontact tonometers. The lenses were swapped between eyes during a second session of measurements, one week later. In the first session with the +6D lenses, the average IOPs (±SDs) before, with the lenses fitted, and after the lenses were removed, were: 14.3 ± 2.9 mmHg, 17.0 ± 3.3 mmHg and 13.9 ± 3.1 mmHg, respectively, for the CT80 and 13.6 ± 3.1 mmHg, 17.1 ± 4.5 mmHg and 13.3 ± 2.9 mmHg, respectively, for the PT100. The corresponding values for the first session with the -6D lenses were: 14.3 ± 3.1 mmHg, 13.1 ± 3.1 mmHg and 14.1 ± 3.3 mmHg, respectively, for the CT80 and 13.6 ± 3.2 mmHg, 13.0 ± 3.0 mmHg and 13.6 ± 3.2 mmHg, respectively, for the PT100. IOP significantly (Psoft contact lens-induced changes were consistent between sessions but varied between tonometers. The measurement of IOP through soft contact lenses resulted in consistent, statistically significant differences in IOP, which were not uniform across tonometers and which did not appear to be solely related to the central thickness of the soft contact lenses. Copyright © 2012 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  9. Verification of aspheric contact lens back surfaces.

    Science.gov (United States)

    Dietze, Holger H; Cox, Michael J; Douthwaite, William A

    2003-08-01

    To suggest a tolerance level for the degree of asphericity of aspheric rigid gas-permeable contact lenses and to find a simple method for its verification. Using existing tolerances for the vertex radius, tolerance limits for eccentricity and p values and were calculated. A keratometer-based method and a method based on sag measurements were used to measure the vertex radius and eccentricity of eight concave progressively aspheric surfaces and six concave ellipsoidal surfaces. The results were compared with a gold standard measurement made using a high-precision mechanical instrument (Form Talysurf). The suggested tolerance for eccentricity and p value and is +/-0.05. The keratometer method was very accurate and precise at measuring the vertex radius (mean deviation +/- SD from Talysurf results, -0.002 +/- 0.008 mm). The keratometer was more precise than and similar in accuracy to the sag method for measurement of asphericity (mean deviation of keratometer method results from Talysurf results, 0.017 +/- 0.018; mean deviation of sag method results from Talysurf results using five semichords, -0.016 +/- 0.032). Neither method was precise enough to verify the asphericity within the suggested tolerance. The keratometer can be efficiently used to verify the back vertex radius within its International Organization for Standardization tolerance and the back surface asphericity within an eccentricity/p value tolerance of +/-0.1. The method is poor for progressive aspheres with large edge blending zones. Deriving the eccentricity from sag measurements is a potential alternative if the mathematical description of the surface is known. The limiting factor of this method is the accuracy and precision of individual sag measurements.

  10. Comparison of Biofilm Formation Capacities of Two Clinical Isolates of Staphylococcus Epidermidis with and without icaA and icaD Genes on Intraocular Lenses

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    Sertaç Argun Kıvanç

    2017-03-01

    Full Text Available Objectives: To compare biofilm formations of two Staphylococcus epidermidis (S. epidermidis isolates with known biofilm formation capacities on four different intraocular lenses (IOL that have not been studied before. Materials and Methods: Two isolates obtained from ocular surfaces and identified in previous studies and stored at -86 °C in 15% glycerol in the microbiology laboratory of the Anadolu University Department of Biology were purified and used in the study. The isolates were S. epidermidis KA 15.8 (ICA+, a known biofilm producer isolate positive for icaA, icaD and bap genes, and S. epidermidis KA 14.5 (ICA-, known as a non-biofilm producer isolate negative for icaA, icaD and bap genes. The biofilm formation capacities of the 2 isolates on 4 different IOLs were compared. Two of the IOLs were acrylic (UD613 [IOL A], Turkey; SA60AT [IOL B], USA, and the other two were polymethyl methacrylate (PMMA (B60130C [IOL C], India; B55125C [IOL D], India. Bacterial enumeration and optical density measurements were done from biofilms that formed on the IOLs. Biofilms were imaged using scanning electron microscopy. Results: Mean bacterial counts on the IOLs were 7.1±0.4 log10 CFU/mL with the ICA+ isolate, and 6.7±0.8 log10 CFU/mL with the ICA- isolate; there were no statistically significant differences. Biofilm formation was lower with acrylic lenses than PMMA lenses with both isolates (p=0.009 and p=0.013. The highest biofilm production was obtained on IOL C (PMMA (p<0.001 and the lowest was obtained on IOL A (hydrophilic acrylic (p<0.001. Conclusion: Bacterial counts after biofilm formation were lower on acrylic lenses, especially hydrophilic acrylic with hydrophobic properties. Further animal and in vivo studies are required to support the findings of this study.

  11. Visual outcome and changes in corneal endothelial cell density following aphakic iris-fixated intraocular lens implantation in pediatric eyes with subluxated lenses.

    Science.gov (United States)

    Siddiqui, Sorath Noorani; Khan, Ayesha

    2013-01-01

    To evaluate the visual outcome and corneal endothelial cell density after Artisan aphakic intraocular lens (IOL) implantation (Ophtec, Groningen, the Netherlands) in pediatric eyes with subluxated lenses. Artisan aphakic IOLs were implanted in 18 eyes of 11 children with subluxated lenses. Idiopathic subluxations and ectopia lentis due to Marfan syndrome were included, whereas subluxations due to trauma or buphthalmos were excluded. Best-corrected visual acuity (BCVA) and endothelial cell density were monitored. Mean postoperative BCVA and endothelial cell density at last follow-up visit were calculated. The age of children at the time of Artisan aphakic IOL implantation ranged from 8 to 16 years (mean: 11.58 ± 2.9 years). Mean follow-up was 9.12 ± 4.30 months. Mean postoperative logarithm of the minimum angle of resolution BCVA was 0.26 ± 0.13 (P = .001) and mean postoperative endothelial cell density was 2,860 ± 435 cells/mm(2) (P = .000). Mean endothelial cell loss was 17.1%. Artisan aphakic IOL implantation is a safe surgical choice in the management of ectopia lentis in the pediatric age group. It has minimal complications and is less traumatic to pediatric eyes. However, long-term follow-up of these children is required.[J Pediatr Ophthalmol Strabismus 2013;50(3):178-182.]. Copyright 2013, SLACK Incorporated.

  12. Calidad visual en pacientes con lente intraocular multifocal modelo OcuFlex operados de catarata The quality of vision in patients operated on from cataract and implanted with OcuFlex multifocal intraocular lenses

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    Eneida Pérez Candelaria

    2010-01-01

    -operative periods, visual phenomena, centration and location of the intraocular lens and the subjective level of satisfaction of the patients were analyzed. The Excel Microsoft and Word 2003 for XP Windows-supported summary statistics were used. RESULTS: The postoperative average spheral equivalent was -0,59. For low and medium frequencies in binocular vision, average contrast sensitivity was 1,12 log unit in the preoperative and 1,74 log unit in the postoperative. The slit lamp-based biomicroscopy showed that 100% of cases had their intraocular lens centered and the ultrasound biomicroscopy yielded that in 93,75% of cases, the ILO was in the capsular sac. None of the patients mentioned the glare whereas just one patient (12,5% reported night halo vision. All the patients were satisfied. CONCLUSIONS: The multifocal lenses reduce the dependence of patients on glasses after cataract surgery. Therefore, this is a good choice for the recovery of optimal visual function.

  13. Biconvex intraocular lenses and Nd:YAG capsulotomy: Experimental comparison of surface damage with different poly(methyl methacrylate) formulations

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    Downing, J.E.; Alberhasky, M.T. (Greenview Hospital, Bowling Green, KY (USA))

    1990-11-01

    Biconvex posterior chamber lenses have optical advantages and decrease the risk of capsular opacification, but they are more likely to be pitted during ND:YAG capsulotomy because of apposition of the lens to the capsule. This study reports the likelihood of surface damage to different formulations of poly(methyl methacrylate) at the energy levels required to open posterior capsules. Molded lenses are more easily damaged than higher molecular weight lathe-cut materials (P less than .01), as expected. However, by keeping energy output low, even injection-molded lenses showed minimal damage, with mean pit size 39 +/- 39 microns at 1 mJ. By using a converging contact lens, low power, and keeping the focus behind the capsule, damage to all materials tested should be clinically insignificant.

  14. Bilateral implantation of +3.0 D multifocal toric intraocular lenses: results of a US Food and Drug Administration clinical trial.

    Science.gov (United States)

    Lehmann, Robert; Modi, Satish; Fisher, Bret; Michna, Magda; Snyder, Michael

    2017-01-01

    The purpose of this study was to evaluate the clinical outcomes of apodized diffractive +3.0 D multifocal toric intraocular lens (IOL) implantations in subjects with preoperative corneal astigmatism. This was a prospective cohort study conducted at 21 US sites. The study population consisted of 574 subjects, aged ≥21 years, with preoperative astigmatism 0.75-2.82 D, and potential postoperative visual acuity (VA) ≥0.2 logMAR, undergoing bilateral cataract removal by phacoemulsification. The intervention was bilateral implantation of aspheric apodized diffractive +3.0 D multifocal toric or spherical multifocal nontoric IOLs. The main outcome measures were monocular uncorrected near and distance VA and safety at 12 months. A total of 373/386 and 182/188 subjects implanted with multifocal toric and nontoric IOLs, respectively, completed 12-month follow-up after the second implantation. Toric IOLs were nonin-ferior in monocular uncorrected distance (4 m) and near (40 cm) VA but had >1 line better binocular uncorrected intermediate VA (50, 60, and 70 cm) than nontoric IOLs. Toric IOLs reduced cylinder to within 0.50 D and 1.0 D of target in 278 (74.5%) and 351 (94.1%) subjects, respectively. Mean ± standard deviation (SD) differences between intended and achieved axis orientation in the first and second implanted eyes were 5.0°±6.1° and 4.7°±4.0°, respectively. Mean ± SD 12-month IOL rotations in the first and second implanted eyes were 2.7°±5.8° and 2.2°±2.7°, respectively. No subject receiving toric IOLs required secondary surgical intervention due to optical lens properties. Multifocal toric IOLs were noninferior to multifocal nontoric IOLs in uncorrected distance and near VAs in subjects with preexisting corneal astigmatism and effectively corrected astigmatism of 0.75-2.82 D.

  15. Ion beam figuring of silicon aspheres

    Science.gov (United States)

    Demmler, Marcel; Zeuner, Michael; Luca, Alfonz; Dunger, Thoralf; Rost, Dirk; Kiontke, Sven; Krüger, Marcus

    2011-03-01

    Silicon lenses are widely used for infrared applications. Especially for portable devices the size and weight of the optical system are very important factors. The use of aspherical silicon lenses instead of spherical silicon lenses results in a significant reduction of weight and size. The manufacture of silicon lenses is more challenging than the manufacture of standard glass lenses. Typically conventional methods like diamond turning, grinding and polishing are used. However, due to the high hardness of silicon, diamond turning is very difficult and requires a lot of experience. To achieve surfaces of a high quality a polishing step is mandatory within the manufacturing process. Nevertheless, the required surface form accuracy cannot be achieved through the use of conventional polishing methods because of the unpredictable behavior of the polishing tools, which leads to an unstable removal rate. To overcome these disadvantages a method called Ion Beam Figuring can be used to manufacture silicon lenses with high surface form accuracies. The general advantage of the Ion Beam Figuring technology is a contactless polishing process without any aging effects of the tool. Due to this an excellent stability of the removal rate without any mechanical surface damage is achieved. The related physical process - called sputtering - can be applied to any material and is therefore also applicable to materials of high hardness like Silicon (SiC, WC). The process is realized through the commercially available ion beam figuring system IonScan 3D. During the process, the substrate is moved in front of a focused broad ion beam. The local milling rate is controlled via a modulated velocity profile, which is calculated specifically for each surface topology in order to mill the material at the associated positions to the target geometry. The authors will present aspherical silicon lenses with very high surface form accuracies compared to conventionally manufactured lenses.

  16. [Management of post-traumatic aphakia and aniridia: Retrospective study of 17 patients undergoing scleral-sutured artificial iris intraocular lens implantation. Management of aphakia-aniridia with scleral-sutured artificial iris intraocular lenses].

    Science.gov (United States)

    Villemont, A-S; Kocaba, V; Janin-Manificat, H; Abouaf, L; Poli, M; Marty, A-S; Rabilloud, M; Fleury, J; Burillon, C

    2017-09-01

    To evaluate the long-term outcomes of artificial iris intraocular lenses sutured to the sclera for managing traumatic aphakia and aniridia. All consecutive cases receiving a Morcher ® combination implant from June 2008 to February 2016 in Edouard-Herriot Hospital (Lyon, France) were included in this single-center retrospective study. Visual acuity, subjective degree of glare, quality of life and surgical complications were evaluated. Seventeen eyes of 17 patients were included, among which 82% were male. The mean age was 42 years. The injuries consisted of 23.5% contusion and 70.5% open globe injuries, of which 41% were globe ruptures. There was one postoperative case. A penetrating keratoplasty was performed at the same time for eight eyes. The mean follow-up was 32 months. Best-corrected visual acuity improved in 41.2%, remained the same in 17.6% and decreased in 41.2% of our cases. Distance vision averaged 1±0.25 line better and near vision 2.2±0.32 lines better when visual acuity was quantifiable before surgery. Glare improved in 80% of patients and remained stable in 20%, decreasing on average from 3.3/5 [min. 3-max. 4; SD: 0.48] before surgery to 1.9/5 [min. 0-max. 4; SD: 1.197] after surgery. Regarding the esthetic results, 78% of the patients declared themselves reasonably to very satisfied; 57% reported no limitation of activities of daily living, and 43% reported mild limitation. Ocular hypertension and glaucoma, found in 40% of eyes, were the main postoperative complications. Implantation of prosthetic iris device combined with an intraocular lens appears to be safe and effective in reducing glare disability and improving visual acuity. Close, long-term monitoring is essential for the success of this surgery. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Serial corneal endothelial cell loss with lathe-cut and injection-molded posterior chamber intraocular lenses.

    Science.gov (United States)

    Kraff, M C; Sanders, D R; Lieberman, H L

    1983-01-01

    We compared endothelial cell loss of patients implanted with lathe-cut posterior chamber lenses and those implanted with injection-molded lenses over a three-year postoperative period. Results were based on more than 2,500 measurements of corneal endothelial density. Although the technique of cataract extraction (anterior chamber phacoemulsification, posterior chamber phacoemulsification, or planned extracapsular extraction) significantly affected cell loss (P less than .01), the type of implant (lathe-cut or injection-molded) did not. Significant continuing endothelial cell loss did not occur during the first three postoperative years with injection-molded lenses. There was, however, a statistically significant 7% to 15% additional cell loss after surgery over the first two to three postoperative years with lathe-cut implants. There have been no cases of corneal endothelial decompensation developing after implantation of injection-molded or lathe-cut lenses. Because a standard field clinical specular microscope was used in this study, cell counting errors cannot be ruled out as a cause of these findings.

  18. Precision production: enabling deterministic throughput for precision aspheres with MRF

    Science.gov (United States)

    Maloney, Chris; Entezarian, Navid; Dumas, Paul

    2017-10-01

    Aspherical lenses offer advantages over spherical optics by improving image quality or reducing the number of elements necessary in an optical system. Aspheres are no longer being used exclusively by high-end optical systems but are now replacing spherical optics in many applications. The need for a method of production-manufacturing of precision aspheres has emerged and is part of the reason that the optics industry is shifting away from artisan-based techniques towards more deterministic methods. Not only does Magnetorheological Finishing (MRF) empower deterministic figure correction for the most demanding aspheres but it also enables deterministic and efficient throughput for series production of aspheres. The Q-flex MRF platform is designed to support batch production in a simple and user friendly manner. Thorlabs routinely utilizes the advancements of this platform and has provided results from using MRF to finish a batch of aspheres as a case study. We have developed an analysis notebook to evaluate necessary specifications for implementing quality control metrics. MRF brings confidence to optical manufacturing by ensuring high throughput for batch processing of aspheres.

  19. Comparison of visual outcomes and subjective visual quality after bilateral implantation of a diffractive trifocal intraocular lens and blended implantation of apodized diffractive bifocal intraocular lenses

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    Gundersen KG

    2016-05-01

    Full Text Available Kjell G Gundersen,1 Rick Potvin21IFocus Øyeklinikk AS, Haugesund, Norway; 2Science in Vision, Akron, NY, USAPurpose: To compare the visual acuity (VA and quality of vision between bilateral implantation of a trifocal intraocular lens (IOL and blended bifocal IOLs with an intermediate add in the dominant eye and a near add in the nondominant eye.Patients and methods: Patients with either trifocal or blended bifocal IOLs implanted were recruited after surgery. Subjects returned for a single diagnostic visit between 3 and 24 months after surgery. VA was tested at various distances, including low-contrast acuity and acuity at their preferred reading distance. A binocular defocus curve was obtained, and subjective visual function and quality of vision were evaluated.Results: Twenty-five trifocal subjects and 30 blended bifocal subjects were enrolled. There were no significant differences in low-contrast acuity, preferred reading distance, or acuity at that reading distance. Binocular vision at 4 m, 60 cm, and 40 cm was not statistically significantly different. The trifocal provided statistically significantly better visual acuity (P<0.05 at vergences from -0.5 to -1.5 D (from 2 m to 67 cm viewing distance, P<0.05. There was no statistically significant difference in the near vision subscale scores of the 39-question National Eye Institute Visual Function Questionnaire or the overall scores of the Quality of Vision questionnaire, though significantly more trifocal subjects reported that the observed visual disturbances were “bothersome” (P<0.05.Conclusion: Both lens modalities provided subjects with excellent binocular near and distance vision, with similar low rates of visual disturbances and good reported functional vision. The trifocal IOL provided significantly better intermediate VA in the viewing distance range of 2 m to 67 cm, corresponding to viewing things such as a car dashboard or grocery shelf. VA was similar between groups at

  20. Laser iridotomy to treat uveitis-glaucoma-hyphema syndrome secondary to reverse pupillary block in sulcus-placed intraocular lenses: Case series.

    Science.gov (United States)

    Singh, Harmanjit; Modabber, Milad; Safran, Steven G; Ahmed, Iqbal Ike K

    2015-10-01

    To present cases of uveitis-glaucoma-hyphema (UGH) syndrome due to reverse pupillary block in sulcus-placed posterior chamber intraocular lenses (PC IOLs) that were managed with laser peripheral iridotomy (LPI). Community-based subspecialty clinics. Retrospective interventional case series. A chart review of patients with a sulcus-placed PC IOLs presenting with UGH syndrome and reverse pupillary block with posterior iris bowing as diagnosed by gonioscopy and anterior segment optical coherence tomography was carried out. Laser peripheral iridotomy was performed in the eyes included in the study. The main outcome measure was clinical resolution of UGH syndrome. The study included 6 eyes of 6 patients with a mean age of 59.8 years (range 43.0 to 66.0 years) who presented with unilateral UGH syndrome a mean of 28.7 months (range 0.3 to 84.0 months) after PC IOL implantation. All patients were previously myopic, with 5 (83.3%) having a history of vitrectomy. The mean axial length was 27.0 mm ± 1.4 (SD). An LPI was used to treat the reverse pupillary block with resultant improvement in iris profile and resolution of UGH syndrome in all eyes. The mean intraocular pressure decreased from 30.5 ± 10.0 mm Hg on 0.5 ± 0.8 glaucoma medications to 15.5 ± 3.2 mm Hg postoperatively on 0.7 ± 1.2 medications. The UGH syndrome due to reverse pupillary block occurred after sulcus-placed PC IOLs in susceptible patients, those with axial myopia, and post-vitrectomized eyes. The cases were managed with LPIs. Dr. Ahmed is a consultant to Alcon Laboratories, Inc. and Abbott Medical Optics, Inc. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  1. [Comparison of surface light scattering of acrylic intraocular lenses made by lathe-cutting and cast-molding methods--long-term observation and experimental study].

    Science.gov (United States)

    Nishihara, Hitoshi; Ayaki, Masahiko; Watanabe, Tomiko; Ohnishi, Takeo; Kageyama, Toshiyuki; Yaguchi, Shigeo

    2004-03-01

    To compare the long-term clinical and experimental results of soft acrylic intraocular lenses(IOLs) manufactured by the lathe-cut(LC) method and by the cast-molding(CM) method. This was a retrospective study of 20 patients(22 eyes) who were examined in a 5- and 7-year follow-up study. Sixteen eyes were implanted with polyacrylic IOLs manufactured by the LC method and 6 eyes were implanted with polyacrylic IOLs manufactured by the CM method. Postoperative measurements included best corrected visual acuity, contrast sensitivity, biomicroscopic examination, and Scheimpflug slit-lamp images to evaluate surface light scattering. Scanning electron microscopy and three-dimensional surface analysis were conducted. At 7 years, the mean visual acuity was 1.08 +/- 0.24 (mean +/- standard deviation) in the LC group and 1.22 +/- 0.27 in the CM group. Surface light-seatter was 12.0 +/- 4.0 computer compatible tapes(CCT) in the LC group and 37.4 +/- 5.4 CCT in the CM group. Mean surface roughness was 0.70 +/- 0.07 nm in the LC group and 6.16 +/- 0.97 nm in the CM group. Acrylic IOLs manufactured by the LC method are more stable in long-termuse.

  2. Tilt, Decentration, and Internal Higher-Order Aberrations of Sutured Posterior-Chamber Intraocular Lenses in Patients with Open Globe Injuries

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    Xiangjia Zhu

    2017-01-01

    Full Text Available Purpose. To evaluate the tilt, decentration, and internal higher-order aberrations (HOAs of sutured posterior-chamber intraocular lenses (IOLs in patients with open globe injuries. Methods. 46 consecutive patients (47 eyes who underwent transsclerally sutured IOL implantation were enrolled in this prospective cohort study. Nineteen eyes had a history of open globe injury. The tilt and decentration of the IOLs and the visual quality were measured 1 month after surgery. Results. The horizontal tilt and decentration of the IOLs in the open-globe-injury group were significantly higher than those in the control group (both P<0.05. In the open-globe-injury group, the horizontal decentration was significantly greater in the limbus-sclera-involved group (n=11 than in the only-cornea-involved group (n=8, P=0.040. The internal coma, 3rd-order, and total HOA values at pupil sizes of 4 mm (P=0.006 and 6 mm (P=0.013 were significantly higher in the open-globe-injury group than in the controls. Consequently, the optical quality data for the modulation transfer function and the Strehl ratio (all P<0.05 were significantly poorer in the open-globe-injury group. Conclusions. Open globe injuries damage the structural integrity of the eyeball, resulting in more-misaligned sutured IOLs and poorer visual quality.

  3. HANGING BY A THREAD: THE LONG-TERM EFFICACY AND SAFETY OF TRANSSCLERAL SUTURED INTRAOCULAR LENSES IN CHILDREN (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS)

    Science.gov (United States)

    Buckley, Edward G.

    2007-01-01

    Purpose To evaluate the long-term efficacy, safety, and advisability of using transscleral sutured posterior chamber intraocular lenses (IOLs) in pediatric patients with no capsular support and to determine whether 10-0 polypropylene suture should be used for this purpose. Methods A long-term retrospective interventional case series review of 33 eyes of 26 patients who had a sutured IOL at Duke University Eye Center were evaluated for the intraoperative surgical risks, postoperative visual and refractive outcomes, and the number, type, and severity of the postoperative complications. In addition, a survey of pediatric ophthalmologists’ experience with suture breakage was performed. Results Postoperative visual acuity was significantly improved after surgery (P subluxation of the IOL secondary to spontaneous 10-0 polypropylene suture breakage at 3.5, 8, and 9 years after surgery. A survey of pediatric ophthalmologists revealed 10 similar cases (mean, 5 years after surgery). Conclusion Transscleral fixation of an IOL in a child appears to be a safe and effective procedure provided that the suture material used is stable enough to resist significant degradation over time. Caution should be exercised in the use of 10-0 polypropylene suture to fixate an IOL to the sclera in children, and an alternative material or size should be considered. PMID:18427618

  4. Comparison of posterior capsule folds following intracapsular implantation of three types of intraocular lenses with different haptic design

    Directory of Open Access Journals (Sweden)

    Ling-Lin Zhang

    2018-04-01

    Full Text Available AIM: To compare the incidence of posterior capsule folds among different types of intraocular lens(IOLto determine risk factors of posterior capsule folds. METHODS:It was a retrospective study. We collected the cases in which the patients underwent phacoemulsification(PHACOand IOL implantation and at least one of the three types of IOL was implanted, including 2-haptic 3-piece IOLs(HOYA PY60AD, 4-haptic 1-piece IOLs(Bausch & Lomb AO, 2-haptic 1-piece IOLs(AMO Tecnis ZCB00. The posterior capsule folds were measured using slit lamp microscope 2d after the surgery. Information of patient's age, gender, length of ocular axis, intraocular pressure, types of IOL were recorded. Posterior capsule fold risk indicators were identified by using logistic regression analysis. RESULTS: One hundred eighty-seven patients(242 eyeshad been collected, including 80 eyes implanted with HOYA PY60AD IOLs, 81 eyes implanted with Bausch & Lomb AO IOLs, 81 eyes implanted with AMO Tecnis ZCB00 IOLs. The incidence of posterior capsule folds of patients implanted with HOYA PY60AD IOLs was significantly higher than those of patients implanted with AMO Tecnis ZCB00 IOLs(56.3% vs 38.3%, P=0.027. While the incidence of patients implanted with Bausch & Lomb AO IOLs was significantly lower than those of patients implanted with AMO Tecnis ZCB00 IOLs(14.8% vs 38.3%, P=0.001. Multi-factor logistics regression analysis demonstrated that independent risk factors were type of IOLs and length of ocular axis. Compared with AMO Tecnis ZCB00 IOLs, using HOYA PY60AD IOLs increased the risk of posterior capsule folds \\〖P=0.020, OR(95%CI=2.145(1.129,4.073\\〗, while using Bausch & Lomb AO IOLs reduced the risk \\〖P=0.001, OR(95%CI=0.274(0.127, 0.591\\〗. Shorter ocular axis might increase the risk of posterior capsule folds \\〖P=0.012, OR(95%CI=0.669(0.489, 0.915\\〗. CONCLUSION: Haptic design should be an important consideration in IOL design. Compared with AMO Tecnis ZCB00 IOLs

  5. Manipulating quantum states with aspheric lenses

    International Nuclear Information System (INIS)

    Wang Zhiwei; Ren Xifeng; Huang Yunfeng; Zhang Yongsheng; Guo Guangcan

    2005-01-01

    We present an experimental demonstration to manipulate the width and position of the down-converted beam waist. Our results can be used to engineer the two-photon orbital angular momentum (OAM) entangled states (such as concentrating OAM entangled states) and generate Hermite-Gaussian (HG) modes entangled states

  6. Comparative evaluation of rotational stability and visual outcome of toric intraocular lenses with and without a capsular tension ring.

    Science.gov (United States)

    Rastogi, Anju; Khanam, Samreen; Goel, Yashpal; Thacker, Prolima; Kumar, Prateek

    2018-03-01

    To evaluate the rotational stability of toric intraocular lens (IOL) when co-implanted with a capsular tension ring (CTR) as compared to that of a toric IOL without a CTR. This was a prospective randomized clinical trial performed in a tertiary care centre in India. Fifty adult human eyes with visually significant cataract and regular corneal astigmatism ≥1.5D divided into two groups of 25 eyes each, A and B by simple randomization. Eyes with corneal pathology, lens subluxation, and a specular endothelial cell count IOL. In Group A, a CTR was put in the bag before IOL implantation. The groups were called for follow-up on day 1, 1 week, 1 month, and 3 months, postoperatively. The axis of the toric IOL on each visit was measured by slit lamp imaging in retroillumination and analyzed digitally. Mean rotation of toric IOL at 3 months postoperatively was 1.85 ± 1.72° in Group A and 4.02 ± 2.04° in Group B. The difference was statistically significant (P = 0.003). Coimplantation of a CTR is a safe and effective technique for ensuring better rotational stability of toric IOLs.

  7. Comparative evaluation of rotational stability and visual outcome of toric intraocular lenses with and without a capsular tension ring

    Directory of Open Access Journals (Sweden)

    Anju Rastogi

    2018-01-01

    Full Text Available Purpose: To evaluate the rotational stability of toric intraocular lens (IOL when co-implanted with a capsular tension ring (CTR as compared to that of a toric IOL without a CTR. Methods: This was a prospective randomized clinical trial performed in a tertiary care centre in India. Fifty adult human eyes with visually significant cataract and regular corneal astigmatism ≥1.5D divided into two groups of 25 eyes each, A and B by simple randomization. Eyes with corneal pathology, lens subluxation, and a specular endothelial cell count <2000/mm2 were excluded from the study. The eyes in both the groups underwent standard phacoemulsification and were implanted with a toric IOL. In Group A, a CTR was put in the bag before IOL implantation. The groups were called for follow-up on day 1, 1 week, 1 month, and 3 months, postoperatively. The axis of the toric IOL on each visit was measured by slit lamp imaging in retroillumination and analyzed digitally. Results: Mean rotation of toric IOL at 3 months postoperatively was 1.85 ± 1.72° in Group A and 4.02 ± 2.04° in Group B. The difference was statistically significant (P = 0.003. Conclusion: Coimplantation of a CTR is a safe and effective technique for ensuring better rotational stability of toric IOLs.

  8. Psychophysical Measurements of Luminance Contrast Sensitivity and Color Discrimination with Transparent and Blue-Light Filter Intraocular Lenses.

    Science.gov (United States)

    da Costa, Marcelo Fernandes; Júnior, Augusto Paranhos; Lottenberg, Claudio Luiz; Castro, Leonardo Cunha; Ventura, Dora Fix

    2017-12-01

    The purpose of this study was to measure luminance contrast sensitivity and color vision thresholdfs in normal subjects using a blue light filter lens and transparent intraocular lens material. Monocular luminance grating contrast sensitivity was measured with Psycho for Windows (version 2.36; Cambridge Research Systems) at 3.0, 6.0, 12.0, 20.0, and 30.0 cycles per degree of visual angle (cpd) in 15 normal subjects (eight female), with a mean age of 21.6 years (SD = 3.8 years). Chromatic discrimination was assessed with the Cambridge colour test (CCT) along the protan, deutan, and tritan color confusion axes. Both tests were performed in a darkened room under two situations: with a transparent lens and with blue light filter lens. Subjective impressions were taken by subjects regarding their visual experience under both conditions. No difference was found between the luminance contrast sensitivity measured with transparent and blue light filter. However, 13/15 (87%) of the subjects reported more comfortable vision with the blue filter. In the color vision test, tritan thresholds were significantly higher for the blue filter compared with the transparent filter (p = 0.003). For protan and deutan thresholds no differences were found. Blue-yellow color vision is impaired with the blue light filter, and no impairment occurs with the transparent filter. No significant differences in thresholds were found in the luminance contrast sensitivity comparing the blue light and transparent filters. The impact of short wavelength light filtering on intrinsically photosensitive retinal ganglion cells is also discussed.

  9. Comparison of intraocular pressure measurement with Scheimpflug-based noncontact tonometer with and without hydrogel contact lenses.

    Science.gov (United States)

    Kumar, Mukesh; Shetty, Rohit; Jayadev, Chaitra; Dutta, Debarun; Nicolsan, Maneck D; Nagaraj, Sriharsha; Kumar, Rajesh S

    2015-04-01

    The objective was to determine the repeatability of intraocular pressure (IOP) measurements made through a soft contact lens (CL) using the Scheimpflug noncontact tonometry in healthy subjects. This prospective, randomized, single-center study included one eye of 88 subjects (40 male and 48 female). Only participants without glaucoma or any other ocular pathology were included in this study. Three consecutive IOP measurements by the Scheimpflug noncontact tonometry were performed with and without daily disposable hydrogel CLs (-0.50 DS) (Dailies-nelfilcon A, 69% water, 8.7 mm base curve, 14 mm diameter, center thickness 0.10 mm) by a single operator. To avoid any bias arising from diurnal variation, all measurements were made at a similar time of day (11 am ± 1 h). The repeatability of IOP measurements using the Scheimpflug noncontact tonometry with and without CLs was evaluated using Pearson's correlation analysis. Bland-Altman plotting was used to assess the limits of agreement between the measurements with and without CLs. The mean (± standard deviation) IOPs with and without CL were 13.80 ± 2.70 and 13.79 ± 2.54 mm of Hg respectively. The mean difference was 0.01 ± 0.16 (95% confidence interval, +1.97 to - 2.00) mm Hg. Statistical analysis via paired t-test showed no statistical difference between the two groups with (P = 0.15). A good correlation was found for IOP measurements with and without CL (r = 0.93, P < 0.001). Good test-retest reliability was found when IOP was measured with and without CL. There was no significant difference between IOP measured with and without CLs by Scheimpflug noncontact tonometry.

  10. Comparison of intraocular pressure measurement with Scheimpflug-based noncontact tonometer with and without hydrogel contact lenses

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar

    2015-01-01

    Full Text Available Objectives: The objective was to determine the repeatability of intraocular pressure (IOP measurements made through a soft contact lens (CL using the Scheimpflug noncontact tonometry in healthy subjects. Methods: This prospective, randomized, single-center study included one eye of 88 subjects (40 male and 48 female. Only participants without glaucoma or any other ocular pathology were included in this study. Three consecutive IOP measurements by the Scheimpflug noncontact tonometry were performed with and without daily disposable hydrogel CLs (−0.50 DS (Dailies-nelfilcon A, 69% water, 8.7 mm base curve, 14 mm diameter, center thickness 0.10 mm by a single operator. To avoid any bias arising from diurnal variation, all measurements were made at a similar time of day (11 am ± 1 h. The repeatability of IOP measurements using the Scheimpflug noncontact tonometry with and without CLs was evaluated using Pearson′s correlation analysis. Bland-Altman plotting was used to assess the limits of agreement between the measurements with and without CLs. Results: The mean (± standard deviation IOPs with and without CL were 13.80 ± 2.70 and 13.79 ± 2.54 mm of Hg respectively. The mean difference was 0.01 ± 0.16 (95% confidence interval, +1.97 to − 2.00 mm Hg. Statistical analysis via paired t-test showed no statistical difference between the two groups with (P = 0.15. A good correlation was found for IOP measurements with and without CL (r = 0.93, P < 0.001. Good test-retest reliability was found when IOP was measured with and without CL. Conclusion: There was no significant difference between IOP measured with and without CLs by Scheimpflug noncontact tonometry.

  11. Inability to perform posterior segment monitoring by scanning laser ophthalmoscopy or optical coherence tomography with some occlusive intraocular lenses in clinical use.

    Science.gov (United States)

    Yusuf, Imran H; Peirson, Stuart N; Patel, Chetan K

    2012-03-01

    To evaluate whether occlusive intraocular lenses (IOLs) produced by several manufacturers for clinical use equivalently transmit near-infrared (IR) light for scanning laser ophthalmoscopy (SLO) or optical coherence tomography (OCT) imaging. Nuffield Laboratory of Ophthalmology, Oxford University, United Kingdom. Evaluation of diagnostic test or technology. The study evaluated 6 black IOLs of 2 designs: 3 poly(methyl methacrylate) (PMMA) and 3 iris-claw anterior chamber IOLs. Each IOL was placed between a broad-spectrum white light source and a spectroradiometer to generate transmission spectra. Transmission in the near-IR range was examined using an 850 nm light-emitting diode. Scanning laser ophthalmoscopy or OCT imaging using Spectralis spectral-domain SLO or OCT was attempted through occlusive IOLs in a model eye. Artisan iris-claw and MS 612 PMMA occlusive IOLs totally occluded all wavelengths of light, including in the near IR range in which SLO and OCT imaging systems operate. It was not possible to capture SLO or OCT images through the iris-claw and PMMA occlusive IOLs in a model eye. Results suggest the property of near-IR transmission that permits SLO or OCT imaging through occlusive IOLs is restricted to the Morcher range of occlusive IOLs. Patients with non-near IR transmitting IOLs will not be able to receive detailed posterior segment monitoring with SLO or OCT. This finding may have a significant impact on preoperative occlusive IOL selection and the management of current patients with occlusive IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  12. Controlled release of moxifloxacin from intraocular lenses modified by Ar plasma-assisted grafting with AMPS or SBMA: An in vitro study.

    Science.gov (United States)

    Pimenta, A F R; Vieira, A P; Colaço, R; Saramago, B; Gil, M H; Coimbra, P; Alves, P; Bozukova, D; Correia, T R; Correia, I J; Guiomar, A J; Serro, A P

    2017-08-01

    Intraocular lenses (IOLs) present an alternative for extended, local drug delivery in the prevention of post-operative acute endophthalmitis. In the present work, we modified the surface of a hydrophilic acrylic material, used for manufacturing of IOLs, through plasma-assisted grafting copolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) or [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), with the aim of achieving a controlled and effective drug release. The material was loaded with moxifloxacin (MFX), a commonly used antibiotic for endophthalmitis prevention. The characterization of the modified material showed that relevant properties, like swelling capacity, wettability, refractive index and transmittance, were not affected by the surface modification. Concerning the drug release profiles, the most promising result was obtained when AMPS grafting was done in the presence of MFX. This modification led to a higher amount of drug being released for a longer period of time, which is a requirement for the prevention of endophthalmitis. The material was found to be non-cytotoxic for rabbit corneal endothelial cells. In a second step, prototype IOLs were modified with AMPS and loaded with MFX as previously and, after sterilization and storage (30days), they were tested under dynamic conditions, in a microfluidic cell with volume and renovation rate similar to the eye aqueous humour. MFX solutions collected in this assay were tested against Staphylococcus aureus and Staphylococcus epidermidis and the released antibiotic proved to be effective against both bacteria until the 12th day of release. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Acoustic lenses

    International Nuclear Information System (INIS)

    Kittmer, C.A.

    1983-03-01

    Acoustic lenses focus ultrasound to produce pencil-like beams with reduced near fields. When fitted to conventional (flat-faced) transducers, such lenses greatly improve the ability to detect and size defects. This paper describes a program developed to design acoustic lenses for use in immersion or contact inspection, using normal or angle beam mode with flat or curved targets. Lens surfaces are circular in geometry to facilitate machining. For normal beam inspection of flat plate, spherical or cylindrical lenses are used. For angle beam or curved surface inspections, a compound lens is required to correct for the extra induced aberration. Such a lens is aspherical with one radius of curvature in the plane of incidence, and a different radius of curvature in the plane perpendicular to the incident plane. The resultant beam profile (i.e., location of the acoustic focus, beam diameter, 6 dB working range) depends on the degree of focusing and the transducer used. The operating frequency and bandwidth can be affected by the instrumentation used. Theoretical and measured beam profiles are in good agreement. Various applications, from zone focusing used for defect sizing in thick plate, to line focusing for pipe weld inspection, are discussed

  14. Influence of a new surface modification of intraocular lenses with fluoroalkylsilan on the adherence of endophthalmitis-causing bacteria in vitro.

    Science.gov (United States)

    Kienast, Antonia; Kämmerer, Regine; Weiss, Claudia; Klinger, Matthias; Menz, Dirk-Henning; Dresp, Joachim; Ohgke, Helge; Solbach, Werner; Laqua, Horst; Hoerauf, Hans

    2006-09-01

    Dynasilan is a fluoroalkylsilan that is able to interact with surface active centres on intraocular lenses (IOL), offering a new way for surface modification of different IOL materials. The purpose of this in vitro study was to investigate the influence of this new surface modification on the adherence of two typical endophthalmitis causing bacteria (Staphylococcus epidermidis, Propionibacterium acnes). In a pilot experiment, the effect of Dynasilan coating on the adherence of S. epidermidis was tested on glass slides. Forty-two Dynasilan-modified and 42 unmodified IOL (14 PMMA, 14 silicone and 14 hydrogel) were incubated at 37 degrees C in brain heart infusion broth (10(8) CFU/ml) with either S. epidermidis for 24 h or with P. acnes for 1 h. Subsequently, the adherent bacteria were resuspended using ultrasonification at 35 kHz for 3x45 s. After dilution series and incubation at 37 degrees C on Petri dishes for 24 h and 3 days, respectively, the colonies were counted. In the pilot experiment, a markedly lower number of adherent S. epidermidis was observed on Dynasilan-modified glass slides. Of all IOL materials incubated with S. epidermidis, those modified with Dynasilan showed a lower mean number of adherent bacteria (mean 1.37x10(7); SD 2.37x10(7)) than those untreated (2.43x10(7); SD 3.04x10(7)). IOLs incubated with P. acnes showed a significantly lower mean number of adherent bacteria of 2.51x10(4) (SD 2.71x10(4)) on Dynasilan-modified IOLs versus 6.27x10(4) (SD 7.70x10(4)) on untreated IOLs. The presented in vitro results indicate that Dynasilan surface modification is able to reduce the adherence of S. epidermidis and P. acnes on all IOL materials tested. Further studies regarding the stability of this modification and its biocompatibility must be performed.

  15. Simulation of an Aspheric Glass Lens Forming Behavior in Progressive GMP Process

    International Nuclear Information System (INIS)

    Chang, Sung Ho; Lee, Young Min; Kang, Jeong Jin; Hong, Seok Kwan; Shin, Gwang Ho; Heo, Young Moo; Jung, Tae Sung

    2007-01-01

    Recently, GMP(Glass Molding Press) process is mainly used to produce aspheric glass lenses. Because glass lens is heated at high temperature above Tg (Transformation Temperature) for forming the glass, the quality of aspheric glass lens is deteriorated by residual stresses which are generated in a aspheric glass lens after forming. In this study, as a fundamental study to develop the mold for progressive GMP process, we conducted a aspheric glass lens forming simulation. Prior to a aspheric glass lens forming simulation, compression and thermal conductivity tests were carried out to obtain mechanical and thermal properties of K-PBK40 which is newly developed material for precision molding, and flow characteristics of K-PBK40 were obtained at high temperature. Then, using the flow characteristics obtained, compression simulation was carried out and compared with the experimental result for the purpose of verifying the obtained flow characteristics. Finally, a glass lens press simulation in progressive GMP process was carried out and we could forecast the shape of deformed glass lenses and residual stresses contribution in the structure of deformed glass lenses after forming

  16. A contralateral eye study comparing apodized diffrative and full diffrative lenses: wavefront analysis and distance and near uncorrected visual acuity

    Directory of Open Access Journals (Sweden)

    Marcony Rodrigues de Santhiago

    2009-01-01

    Full Text Available PURPOSE: To evaluate intraindividual visual acuity, wavefront errors and modulation transfer functions in patients implanted with two diffractive multifocal intraocular lenses. METHODS: This prospective study examined 40 eyes of 20 cataract patients who underwent phacoemulsification and implantation of a spherical multifocal ReSTOR intraocular lens in one eye and an aspheric Tecnis ZM900 multifocal intraocular lens in the other eye. The main outcome measures, over a 3-month follow-up period, were the uncorrected photopic distance and near visual acuity and the defocus curve. The visual acuity was converted to logMAR for statistical analysis and is presented in decimal scale. The wavefront error and modulation transfer function were also evaluated in both groups. RESULTS: At the 3-month postoperative visit, the mean photopic distance uncorrected visual acuity (UCVA was 0.74 ± 0.20 in the ReSTOR group and 0.76 ± 0.22 in the Tecnis group (p=0.286. The mean near UCVA was 0.96 ± 0.10 in the ReSTOR group and 0.93 ± 0.14 in the Tecnis group (p=0.963. The binocular defocus curve showed measurements between the peaks better than 0.2 logMAR. The total aberration, higher-order aberration and coma aberration were not significantly different between the groups. The spherical aberration was significantly lower in the Tecnis group than in the ReSTOR group. (p=0.004. Both groups performed similarly for the modulation transfer function. CONCLUSION: The ReSTOR SN60D3 and Tecnis ZM 900 intraocular lenses provided similar photopic visual acuity at distance and near. The diffractive intraocular lenses studied provided a low value of coma and spherical aberrations, with the Tecnis intraocular lens having a statistically lower spherical aberration compared to the ReSTOR intraocular lens. In the 5 mm pupil diameter analyses, both intraocular lens groups showed similar modulation transfer functions.

  17. Pigment dispersion syndrome and pigmentary glaucoma after secondary sulcus transscleral fixation of single-piece foldable posterior chamber intraocular lenses in Chinese aphakic patients.

    Science.gov (United States)

    Tong, Nianting; Liu, Fuling; Zhang, Ting; Wang, Liangyu; Zhou, Zhanyu; Gong, Huimin; Yuan, Fuxiang

    2017-05-01

    To describe secondary pigment dispersion syndrome (PDS) and pigmentary glaucoma after secondary sulcus transscleral fixation of 1-piece hydrophobic acrylic foldable posterior chamber intraocular lenses (PC IOLs) in aphakic patients in a Chinese population. Department of Ophthalmology, Qingdao Municipal Hospital, Qingdao, China. Retrospective case series. This chart review included eyes that had secondary sulcus transscleral fixation of a 1-piece hydrophobic acrylic foldable PC IOL (Tecnis ZCB00) between March 2011 and March 2014. The patients' demographic data, clinical data, postoperative complications, intervals between initial surgery and the onset of PDS, pigmentary glaucoma occurrences, and findings on slitlamp biomicroscopy, gonioscopy, and ultrasound biomicroscopy (UBM) were recorded. The study comprised 23 consecutive eyes of 21 patients. Seventeen eyes of 16 patients were diagnosed with PDS, and 7 eyes of 6 patients were diagnosed with pigmentary glaucoma. The slitlamp examination and UBM showed that the location between the IOL optic and the posterior surface of the iris was very close. Slitlamp examination of the anterior chamber angle using a gonioscope showed dense pigment deposition on the IOL surfaces. A reverse pupillary block was found in 10 eyes of 9 patients. Other postoperative complications included intraocular hemorrhage, pupillary capture of the IOL optic, IOL tilt, IOL decentration, IOL dislocation, and suture erosion. The 1-piece hydrophobic acrylic foldable PC IOL was not suitable for sulcus transscleral fixation because of a high incidence of PDS and pigmentary glaucoma after surgery in a Chinese population. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  18. Surface characterization protocol for precision aspheric optics

    Science.gov (United States)

    Sarepaka, RamaGopal V.; Sakthibalan, Siva; Doodala, Somaiah; Panwar, Rakesh S.; Kotaria, Rajendra

    2017-10-01

    In Advanced Optical Instrumentation, Aspherics provide an effective performance alternative. The aspheric fabrication and surface metrology, followed by aspheric design are complementary iterative processes for Precision Aspheric development. As in fabrication, a holistic approach of aspheric surface characterization is adopted to evaluate actual surface error and to aim at the deliverance of aspheric optics with desired surface quality. Precision optical surfaces are characterized by profilometry or by interferometry. Aspheric profiles are characterized by contact profilometers, through linear surface scans to analyze their Form, Figure and Finish errors. One must ensure that, the surface characterization procedure does not add to the resident profile errors (generated during the aspheric surface fabrication). This presentation examines the errors introduced post-surface generation and during profilometry of aspheric profiles. This effort is to identify sources of errors and is to optimize the metrology process. The sources of error during profilometry may be due to: profilometer settings, work-piece placement on the profilometer stage, selection of zenith/nadir points of aspheric profiles, metrology protocols, clear aperture - diameter analysis, computational limitations of the profiler and the software issues etc. At OPTICA, a PGI 1200 FTS contact profilometer (Taylor-Hobson make) is used for this study. Precision Optics of various profiles are studied, with due attention to possible sources of errors during characterization, with multi-directional scan approach for uniformity and repeatability of error estimation. This study provides an insight of aspheric surface characterization and helps in optimal aspheric surface production methodology.

  19. Subjective evaluation of uncorrected vision in patients undergoing cataract surgery with (diffractive multifocal lenses and monovision

    Directory of Open Access Journals (Sweden)

    Stock RA

    2017-07-01

    Full Text Available Ricardo Alexandre Stock, Thaís Thumé, Luan Gabriel Paese, Elcio Luiz Bonamigo Universidade do Oeste de Santa Catarina, Rua Getúlio Vargas, Joaçaba, Santa Catarina, Brazil Purpose: To analyze patient satisfaction and difficulties with bilateral multifocal intraocular lenses (IOLs implantation and aspheric monofocal IOLs implantation using monovision, after cataract surgery.Materials and methods: A total of 61 participants were included in the study, 29 with monovision and 32 with multifocal lenses. The inclusion criteria were patients undergoing phacoemulsification for bilateral visual impairment due to cataracts and presenting with postoperative visual acuity of 20/30 or better for distance and line J3 or better for near vision.Results: The 2 groups had similar results regarding difficulties with daily activities such as distance vision, near vision, watching television, reading, cooking, using a computer or cellphone, shaving/putting on makeup and shopping. There were differences in responses between the groups regarding difficulty with night vision (P=0.0565 and night driving (P=0.0291. Degree of satisfaction in terms of distance vision without glasses was statistically significantly better in monovision group (P=0.0332, but not for near (P=0.9101.Conclusion: Both techniques yielded satisfactory results regarding visual acuity for different activities without the need to use glasses. Multifocal lenses are a good option for patients with the exception of night driving, and who desire independence from glasses. Keywords: cataract extraction, aphakia, postcataract, patient satisfaction, night vision

  20. Comparison between OPD-Scan results and visual outcomes of monofocal and multifocal intraocular lenses Comparação dos resultados do OPD-Scan e performance visual das lentes intraoculares monofocal e multifocal

    Directory of Open Access Journals (Sweden)

    Wilson Takashi Hida

    2009-08-01

    Full Text Available PURPOSE: To compare the visual outcome, contrast sensitivity and wavefront analysis of patients that underwent cataract surgery and implantation of AcrySof SN60D3 multifocal intraocular lens with those who received the AcrySof SN60AT monofocal IOL. METHODS: This was a prospective clinical trial of forty eyes that received the multifocal IOL and thirty-two eyes that received the monofocal IOL after phacoemulsification. RESULTS: Values for total and spherical aberrations in the multifocal group were statistically lower than in the monofocal group. In the monofocal group, 75% achieved uncorrected intermediate visual acuities between Jaeger 1 and 6. In the multifocal group, 75% of the eyes achieved more than Jaeger 6. At least 87.5% of the multifocal group and 6.3% of the monofocal group achieved monocular uncorrected near acuity of 20/30 (J2, N5 or better. And 90.0% of the eyes in the multifocal group and 37.5% in the monofocal group achieved an uncorrected near acuity of 20/40 (J3, N6 or better. The mean spherical error was 0.11 D in the multifocal group and -0.18 D in the monofocal group (p=0.0379. The SN60D3 group compared to SN60AT group had low contrast sensitivity (log units with statistically significant differences in 6.0 cpd in photopic conditions (p=0.014 and the SN60D3 group compared to SN60AT group had higher contrast sensitivity (log units under mesopic conditions (p=0.044. CONCLUSION: The multifocal IOLs induced less spherical aberration than monofocal IOLs and predictably good uncorrected distance and uncorrected near acuities. However, contrast sensitivity was lower in the multifocal group.OBJETIVO: Comparar a performance visual, sensibilidade ao contraste e de wavefront com OPD-Scan em pacientes submetidos a cirurgia de facoemulsificação com implante de lente intraocular AcrySof SN60D3 multifocal e AcrySof SA60AT monofocal. MÉTODOS: Quarenta olhos com a lente intraocular multifocal e trinta e dois olhos com a lente intraocular

  1. Biomicroscopia ultra-sônica na avaliação da posição das lentes intra-oculares em uma técnica de fixação escleral Ultrasound biomicroscopy in the assessment of the intraocular lenses positioning in a transscleral fixation technique

    Directory of Open Access Journals (Sweden)

    Raul de Camargo Vianna Filho

    2000-10-01

    Full Text Available Objetivo: Avaliar pela biomicrospia ultra-sônica (UBM o posicionamento, em relação ao sulco ciliar, das alças de lentes intra-oculares (LIO, em uma técnica de fixação escleral, avaliando-se também se dois pontos de fixação são suficientes para que não haja inclinação da parte óptica. Métodos: Dezesseis olhos afácicos foram submetidos a implante LIO por uma mesma técnica de fixação escleral, realizados por um mesmo cirurgião. Um mês após a cirurgia, o posicionamento das alças das LIO foram avaliados pelo UBM, assim como distâncias entre as LIO e córnea. Os resultados foram submetidos a testes estatísticos. Resultados: Das 32 alças fixadas à esclera, oito estavam localizadas no sulco ciliar e 24 fora deste. Não houve diferença estatística nas distâncias entre LIO e córnea para alças posicionadas no sulco ciliar quando comparadas àquelas localizadas fora do sulco. Isto sugere que, além da distância ao limbo que se transfixa a esclera, outros fatores devem estar associados ao posicionamento da alça no sulco ciliar. As medidas LIO -- córnea realizadas na periferia das LIO às 3, 6, 9, e 12 horas foram semelhantes, mostrando que dois pontos de fixação são suficientes para que a LIO não fique inclinada. Conclusões: Outros fatores (por exemplo o ângulo de abertura do corpo ciliar, além da distância ao limbo na qual se transfixa a esclera, são importantes para o posicionamento das alças no sulco ciliar. Dois pontos de fixação são suficientes para que a LIO não apresente inclinação dentro do olho.Purpose: To assess, through ultrasound biomicroscopy (UBM, the positioning of the intraocular lenses (IOL haptics as related to the ciliary sulcus by using a scleral fixation technique; and to evaluate, as well, if two fixation points are sufficient to avoid tilting of the lenses. Methods: Sixteen aphakic eyes underwent an IOL implan-tation by means of the same scleral fixation technique, performed by the

  2. Assessment of the safety and efficacy of primary retropupillary fixation of iris-claw intraocular lenses in children with large lens subluxations.

    Science.gov (United States)

    Rastogi, Anju; Goray, Apurva; Thacker, Prolima; Kamlesh; Babita

    2017-08-17

    To evaluate whether retropupillary fixation of the iris-claw intraocular lens (IOL) is a safe and effective treatment option in children with large lens subluxations. Fourteen eyes of children between the ages of 8-17 years with lens subluxations more than 7 clock hours underwent pars plana lensectomy-vitrectomy with implantation of the iris-claw IOL in the retropupillary position as a primary procedure. The best corrected visual acuity (BCVA), intraocular pressure (IOP), corneal endothelial count (EC) and the lens position using ultrasound biomicroscopy (UBM) were assessed pre- and postoperatively. Postoperatively, all patients had an increase in the BCVA with a mean of 0.351 ± 0.154 log MAR units which was statistically significant as compared to the preoperative value of 0.771 ± 0.132 log MAR units (p = 0.003). The difference between the mean preoperative IOP (13.642 ± 2.437 mmHg) and the mean postoperative intraocular pressure at the end of 6 months (13.5 ± 2.244 mmHg) was not statistically significant (p = 0.671). The mean EC decreased by 0.99% from 2838.42 ± 474.76 cells/mm 2 preoperatively to 2810 ± 461.24 cells/mm 2 at the end of 6 months postoperatively (p = 0.117). The lens position was analyzed using UBM and was found to be parallel to the iris plane in all cases at the end of 6 months. Our study shows that primary retropupillary iris-claw IOL implantation can be a safe and efficacious option for children with large (>7 clock hours) lens subluxations that is at least comparable to scleral-fixated PCIOLs.

  3. Spectacle Independence after Cataract Extraction in Post-Radial Keratotomy Patients Using Hybrid Monovision with ReSTOR® Multifocal and TECNIS® Monofocal Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Isha Gupta

    2014-05-01

    Full Text Available Background: We report 2 patients who have undergone radial keratotomy (RK preceding ReSTOR® multifocal intraocular lens (IOL; Alcon, Fort Worth, Tex., USA implantation in their nondominant eyes and TECNIS® monofocal IOL (Abbott Medical Optics, Abbott Park, Ill., USA in their dominant eyes. Methods: Retrospective review of 2 patients who underwent hybrid monovision with ReSTOR® multifocal and TECHNIS® monofocal IOLs at the time of cataract surgery after a remote history of RK. Results: Implantation of the ReSTOR® multifocal and the TECHNIS® monofocal IOLs was successful, with no reported adverse events. The patients were able to achieve spectacle freedom. Conclusion: We report a novel technique for the management of post-RK patients to optimize their chances for spectacle independence.

  4. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Mike A. (Albuquerque, NM); Foreman, Larry R. (Los Alamos, NM)

    1997-01-01

    This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

  5. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, M.A.; Foreman, L.R.

    1997-07-08

    This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

  6. Effects of blue light-filtering intraocular lenses on the macula, contrast sensitivity, and color vision after a long-term follow-up.

    Science.gov (United States)

    Kara-Junior, Newton; Espindola, Rodrigo F; Gomes, Beatriz A F; Ventura, Bruna; Smadja, David; Santhiago, Marcony R

    2011-12-01

    To evaluate the possible side effects and potential protection 5 years after implantation of an intraocular lens (IOL) with a blue-light filter (yellow tinted). Ophthalmology Department, University of São Paulo, São Paulo, Brazil. Prospective randomized clinical study. Patients with bilateral visually significant cataract randomly received an ultraviolet (UV) and blue light-filtering IOL (Acrysof Natural SN60AT) in 1 eye and an acrylic UV light-filtering only IOL (Acrysof SA60AT) in the fellow eye. The primary outcome measures were contrast sensitivity, color vision, and macular findings 5 years after surgery. The study enrolled 60 eyes of 30 patients. There were no significant clinical or optical coherence tomography findings in terms of age-related macular degeneration in any eye. There were no statistically significant differences in central macular thickness between the 2 IOL groups (P=.712). There were also no significant between-group differences under photopic or scotopic conditions at any spatial frequency studied. No statistically significant differences in the color discrimination test were found between the 2 IOL groups (P=.674). After 5 years, there were no significant differences in color perception, scotopic contrast sensitivity, or photopic contrast sensitivity between the blue light-filtering (yellow-tinted) IOL and the IOL with a UV-light filter only (untinted). The potential advantage of the tinted IOL in providing protection to macular cells remains unclear. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  7. Comparative measurement of intraocular pressure by Icare tonometry and Airpuff tonometry in healthy subjects and patients wearing therapeutic soft contact lenses.

    Science.gov (United States)

    Anton, Alexandra; Neuburger, Matthias; Böhringer, Daniel; Jordan, Jens F

    2013-07-01

    The aim of the present study was to compare the measurement of intraocular pressure (IOP) through a therapeutic soft contact lens with the "native" measurement. We additionally investigate whether a rebound tonometer (RT) or non-contact tonometer (NCT) is more suitable to measure IOP through a bandage contact lens. The IOP was determined using each of the two methods, three times successively with (lens measurement) and without (native measurement) a soft contact lens. The Icare tonometer (Icare® TA01i, Icare Finland Oy, 23 subjects) and the Airpuff tonometer (Nidek NT 53OP, Nidek CO., LTD, Hiroishi Gamagori, Aichi, Japan, 16 subjects) were used. We compared the mean values (validity parameter) and standard deviation (precision parameter) of the three individual measurements in each case using the paired t-test. In addition, we conducted a power analysis to estimate the maximum error in the measurement caused by the contact lens (power level set to 0.8). With the Airpuff tonometer we detected no statistically significant between the lens and the native measurement (15.6 ± 2.6 vs. 15.3 ± 2.6 mmHg; p = 0.42). The power analysis revealed that the maximum error caused by the contact lens was 1.2 mmHg. The Icare tonometry, however, trended toward higher values in the contact lens measurements (17.5 ± 4.3 vs. 16.4 ± 3.5 mmHg in the native measurements; p = 0.05). Interestingly, this difference exhibited a statistically significant correlation with the corneal thickness (0.03 mmHg per μm corneal thickness; p = 0.04). The use of NCT and RT for IOP measurement over a soft contact lens is feasible. The accuracy appears to be sufficient for the most common clinical applications.

  8. Sutureless, Glueless, Scleral Fixation of Single-Piece and Toric Intraocular Lens: A Novel Technique

    Directory of Open Access Journals (Sweden)

    Aditya Kelkar

    2015-07-01

    Full Text Available Sutureless, glueless, scleral fixation of an intraocular lens is a known technique of fixing a lens in the scleral pockets. However, this technique is applied to single-piece and toric lenses instead of 3-piece lenses, allowing the advantage of the use of premium lenses in patients with poor capsular support. Favourable results without complications of pigment dispersion, iris transillumination defects, dysphotopsia, elevated intraocular pressure, intraocular hemorrhage and cystoid macular edema with a well-centered, stable intraocular lens have been observed in the 3-month postoperative period in both cases.

  9. Injective Labeled Oriented Trees are Aspherical

    OpenAIRE

    Harlander, Jens; Rosebrock, Stephan

    2012-01-01

    A labeled oriented tree is called injective if each generator occurs at most once as an edge label. We show that injective labeled oriented trees are aspherical. The proof relies on a new relative asphericity test based on a lemma of Stallings.

  10. Lathe converted for grinding aspheric surfaces

    Science.gov (United States)

    Larmer, J. W.; Levinsohn, M.; Mc Craw, D.; Pessagno, E. H.; Taub, F. J.

    1964-01-01

    A standard overarm tracing lathe converted by the addition of an independently driven diamond grinding wheel is used for grinding aspheric surfaces. The motion of the wheel is controlled by the lathe air tracer following the template which produces the desired aspheric profile.

  11. 21 CFR 886.4300 - Intraocular lens guide.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4300 Intraocular lens guide. (a) Identification. An intraocular lens guide is a device intended to be inserted into the eye during surgery to direct... lenses, the device is exempt from the premarket notification procedures in subpart E of part 807 of this...

  12. Bacterial contamination of intraocular lens surgery.

    OpenAIRE

    Vafidis, G C; Marsh, R J; Stacey, A R

    1984-01-01

    One hundred sterile intraocular lenses were placed on the external eye of 50 patients during cataract surgery. Half of the specimens were cultured for bacteria, the other half were examined under the light microscope after fixing and staining. A bacterial contamination rate of 26% was recorded. This is significantly higher than that found in conjunctival swabs (6%) or irrigation specimens (8%) taken at the same time, and higher than that recorded in a group of control lenses (15.2%) exposed t...

  13. Resultados del implante múltiple de lentes intraoculares en la cirugía de catarata en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer" Results of the multiple intraocular lenses implantation in the cataract surgery performed at "Ramón Pando Ferrer" Cuban Institute of Ophthalmology

    Directory of Open Access Journals (Sweden)

    Eric Montero Díaz

    2010-06-01

    Full Text Available OBJETIVO: Valorar los resultados visuales de los pacientes operados con la técnica de piggy back o implantes múltiples de lentes intraoculares. MÉTODOS: Se realizó un estudio descriptivo retrospectivo de corte transversal en el que se tomaron 32 ojos de 30 pacientes del universo operado de catarata, con la técnica antes descrita, en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer", en el período comprendido entre enero de 2000 hasta diciembre de 2006. Fueron evaluadas algunas variables demográficas, como edad y sexo, así como agudeza visual y refracción preoperatorio y posoperatoria con cristales y sin ellos. Reportamos las complicaciones transquirúrgicas y posquirúrgicas asociadas a las diferentes técnicas quirúrgicas empleadas para la extracción del cristalino. RESULTADOS: La edad promedio obtenida fue mayor de 50 años, y predominó el sexo femenino. Parte de los pacientes tuvieron una agudeza visual corregida superior a 20/40. La complicación más frecuente fue la opacidad de la cápsula posterior y solo en la tercera parte de los pacientes se obtuvo una buena corrección refractiva. CONCLUSIONES: La técnica de piggy back permitió la recuperación de cuatro líneas en la cartilla de Snellen en la agudeza visual corregida, mientras que en la agudeza visual sin corrección solo aumentó en dos líneas. Se encontró igual número de pacientes hipocorregidos y bien corregidos.OBJECTIVE: To asses the visual results of patients operated on by piggy back technique or multiple implantation of intraocular lenses METHODS: A retrospective cross-sectional descriptive study was conducted in 32 eyes from 30 patients operated on from cataract, using the above-mentioned technique, at "Ramon Pando Ferrer" Cuban Institute of Ophthalmology in the period January 2000 through December 2006. Some demographic variables as age and sex as well as visual acuity and preoperative and postoperative refraction with/without lenses were evaluated

  14. Intraocular lens alignment from purkinje and Scheimpflug imaging.

    Science.gov (United States)

    Rosales, Patricia; De Castro, Alberto; Jiménez-Alfaro, Ignacio; Marcos, Susana

    2010-11-01

    The improved designs of intraocular lenses (IOLs) implanted during cataract surgery demand understanding of the possible effects of lens misalignment on optical performance. In this review, we describe the implementation, set-up and validation of two methods to measure in vivo tilt and decentration of IOLs, one based on Purkinje imaging and the other on Scheimpflug imaging. The Purkinje system images the reflections of an oblique collimated light source on the anterior cornea and anterior and posterior IOL surfaces and relies on the well supported assumption of the linearity of the Purkinje images with respect to IOL tilt and decentration. Scheimpflug imaging requires geometrical distortion correction and image processing techniques to retrieve the pupillary axis, IOL axis and pupil centre from the three-dimensional anterior segment image of the eye. Validation of the techniques using a physical eye model indicates that IOL tilt is estimated within an accuracy of 0.261 degree and decentration within 0.161 mm. Measurements on patients implanted with aspheric IOLs indicate that IOL tilt and decentration tend to be mirror symmetric between left and right eyes. The average tilt was 1.54 degrees and the average decentration was 0.21 mm. Simulated aberration patterns using custom models of the patients eyes, built using anatomical data of the anterior cornea and foveal position, the IOL geometry and the measured IOL tilt and decentration predict the experimental wave aberrations measured using laser ray tracing aberrometry on the same eyes. This reveals a relatively minor contribution of IOL tilt and decentration on the higher-order aberrations of the normal pseudophakic eye.

  15. Aspheric surface measurement using capacitive probes

    Science.gov (United States)

    Tao, Xin; Yuan, Daocheng; Li, Shaobo

    2017-02-01

    With the application of aspheres in optical fields, high precision and high efficiency aspheric surface metrology becomes a hot research topic. We describe a novel method of non-contact measurement of aspheric surface with capacitive probe. Taking an eccentric spherical surface as the object of study, the averaging effect of capacitive probe measurement and the influence of tilting the capacitive probe on the measurement results are investigated. By comparing measurement results from simultaneous measurement of the capacitive probe and contact probe of roundness instrument, this paper indicates the feasibility of using capacitive probes to test aspheric surface and proposes the compensation method of measurement error caused by averaging effect and the tilting of the capacitive probe.

  16. Simulation of aspheric tolerance with polynomial fitting

    Science.gov (United States)

    Li, Jing; Cen, Zhaofeng; Li, Xiaotong

    2018-01-01

    The shape of the aspheric lens changes caused by machining errors, resulting in a change in the optical transfer function, which affects the image quality. At present, there is no universally recognized tolerance criterion standard for aspheric surface. To study the influence of aspheric tolerances on the optical transfer function, the tolerances of polynomial fitting are allocated on the aspheric surface, and the imaging simulation is carried out by optical imaging software. Analysis is based on a set of aspheric imaging system. The error is generated in the range of a certain PV value, and expressed as a form of Zernike polynomial, which is added to the aspheric surface as a tolerance term. Through optical software analysis, the MTF of optical system can be obtained and used as the main evaluation index. Evaluate whether the effect of the added error on the MTF of the system meets the requirements of the current PV value. Change the PV value and repeat the operation until the acceptable maximum allowable PV value is obtained. According to the actual processing technology, consider the error of various shapes, such as M type, W type, random type error. The new method will provide a certain development for the actual free surface processing technology the reference value.

  17. Intraocular lymphoma

    Directory of Open Access Journals (Sweden)

    Li-Juan Tang

    2017-08-01

    Full Text Available Intraocular lymphoma (IOL is a rare lymphocytic malignancy which contains two main distinct forms. Primary intraocular lymphoma (PIOL is mainly a sub-type of primary central nervous system lymphoma (PCNSL. Alternatively, IOL can originate from outside the central nervous system (CNS by metastasizing to the eye. These tumors are known as secondary intraocular lymphoma (SIOL. The IOL can arise in the retina, uvea, vitreous, Bruch’s membrane and optic nerve. There are predominantly of B-cell origin; however there are also rare T-cell variants. Diagnosis remains challenging for ophthalmologists and pathologists, due to its ability to masquerade as noninfectious or infectious uveitis, white dot syndromes, or occasionally as other metastatic cancers. Laboratory tests include flow cytometry, immunocytochemistry, interleukin detection (IL-10: IL-6, ratio >1, and polymerase chain reaction (PCR amplification. Methotrexate-based systemic chemotherapy with external beam radiotherapy and intravitreal chemotherapy with methotrexate are useful for controlling the disease, but the prognosis remains poor. Therefore, it is important to make an early diagnose and treatment. This review is focused on the clinical manifestations, diagnosis, treatment and prognosis of the IOL.

  18. Glass molding of 3mm diameter aspheric plano-convex lens

    Science.gov (United States)

    Sung, Hayeong; Hue, Myung sang; Lee, Giljae; Ryu, Geunman; Kim, Dongguk; Yang, Suncheol

    2017-10-01

    The many industries and research fields have demands for small scale optical systems. To satisfy the demands, many studies are conducted and the miniaturization technologies have been developed. The optical lens is directly related to the optical systems and a key component for the miniaturization. So the aspheric surface which can replace multispherical lenses is applied to the optical lens. And fabrication methods to reduce the diameter of the lens have been developed. The glass molding pressing (GMP) process is an attractive method to fabricate aspheric lens among the lens manufacturing processes. Because the GMP process has advantages of productivity, repeatability and so on. In this study, a 3 mm diameter aspheric plano-convex lens was fabricated using the GMP process. The GMP process was divided into heating, pressing, annealing and cooling. And the process was conducted using a commercial glass molding machine. Mold tools consist of an upper and a lower mold insert, an inner and an outer guide. The aspheric and the flat surfaces of the mold inserts were coated with ta-C to prevent the sticking of the glass to the mold. The surfaces of molded lens were measured by white interferometry and surface profilometer. The height and the diameter were measured using optical microscopy. As results, the aspheric surface of the lens was 5.1187 nm in Ra and 0.242 um in Pt. And the flat surface was 2.6697 nm in Ra and 0.13 um in Pt. The height and the diameter were 1.935 mm and 3.002 mm respectively.

  19. [IOP measurement through frequent-replacement soft contact lenses].

    Science.gov (United States)

    Touboul, J

    2008-07-01

    Intraocular pressure (IOP) can be measured through soft contact lenses with an air-puff tonometer. These measurements seemed accurate for low-power negative lenses. For positive soft contact lenses, IOP is overestimated. The measurement of IOP through a soft contact lens is acceptable in clinical practice only for glaucoma screening. In glaucomatous patients or patients with ocular hypertension, IOP measurements should be performed without a contact lens. The main technique for IOP measurement remains Goldmann applanation tonometry.

  20. Aspherical bubble dynamics and oscillation times

    Energy Technology Data Exchange (ETDEWEB)

    Godwin, R.P.; Chapyak, E.J. [Los Alamos National Lab., NM (United States); Noack, J.; Vogel, A. [Medizinisches Laserzentrum Luebeck (Germany)

    1999-03-01

    The cavitation bubbles common in laser medicine are rarely perfectly spherical and are often located near tissue boundaries, in vessels, etc., which introduce aspherical dynamics. Here, novel features of aspherical bubble dynamics are explored. Time-resolved experimental photographs and simulations of large aspect ratio (length:diameter {approximately}20) cylindrical bubble dynamics are presented. The experiments and calculations exhibit similar dynamics. A small high-pressure cylindrical bubble initially expands radially with hardly any axial motion. Then, after reaching its maximum volume, a cylindrical bubble collapses along its long axis with relatively little radial motion. The growth-collapse period of these very aspherical bubbles differs only sightly from twice the Rayleigh collapse time for a spherical bubble with an equivalent maximum volume. This fact justifies using the temporal interval between the acoustic signals emitted upon bubble creation and collapse to estimate the maximum bubble volume. As a result, hydrophone measurements can provide an estimate of the bubble energy even for aspherical bubbles. The prolongation of the oscillation period of bubbles near solid boundaries relative to that of isolated spherical bubbles is also discussed.

  1. Optimized method for manufacturing large aspheric surfaces

    Science.gov (United States)

    Zhou, Xusheng; Li, Shengyi; Dai, Yifan; Xie, Xuhui

    2007-12-01

    Aspheric optics are being used more and more widely in modern optical systems, due to their ability of correcting aberrations, enhancing image quality, enlarging the field of view and extending the range of effect, while reducing the weight and volume of the system. With optical technology development, we have more pressing requirement to large-aperture and high-precision aspheric surfaces. The original computer controlled optical surfacing (CCOS) technique cannot meet the challenge of precision and machining efficiency. This problem has been thought highly of by researchers. Aiming at the problem of original polishing process, an optimized method for manufacturing large aspheric surfaces is put forward. Subsurface damage (SSD), full aperture errors and full band of frequency errors are all in control of this method. Lesser SSD depth can be gained by using little hardness tool and small abrasive grains in grinding process. For full aperture errors control, edge effects can be controlled by using smaller tools and amendment model with material removal function. For full band of frequency errors control, low frequency errors can be corrected with the optimized material removal function, while medium-high frequency errors by using uniform removing principle. With this optimized method, the accuracy of a K9 glass paraboloid mirror can reach rms 0.055 waves (where a wave is 0.6328μm) in a short time. The results show that the optimized method can guide large aspheric surface manufacturing effectively.

  2. Aspheric surface testing by irradiance transport equation

    Science.gov (United States)

    Shomali, Ramin; Darudi, Ahmad; Nasiri, Sadollah; Asgharsharghi Bonab, Armir

    2010-10-01

    In this paper a method for aspheric surface testing is presented. The method is based on solving the Irradiance Transport Equation (ITE).The accuracy of ITE normally depends on the amount of the pick to valley of the phase distribution. This subject is investigated by a simulation procedure.

  3. Bilateral spontaneous dislocation of posterior chamber intraocular lens in a patient with gyrate atrophy

    Directory of Open Access Journals (Sweden)

    Michael Kinori

    2012-01-01

    Full Text Available We report a patient with gyrate atrophy, a rare metabolic disease, who had bilateral late spontaneous posterior dislocation of in-the-bag posterior chamber intraocular lens (PCIOL. He underwent pars plana vitrectomy, PCIOL retrieval and anterior chamber intraocular lens implantation in both eyes. This report may imply that patients with gyrate atrophy are at risk for spontaneous dislocation of intraocular lenses.

  4. Modified alignment CGHs for aspheric surface test

    Science.gov (United States)

    Song, Jae-Bong; Yang, Ho-Soon; Rhee, Hyug-Gyo; Lee, Yun-Woo

    2009-08-01

    Computer Generated Holograms (CGH) for optical test are commonly consisted of one main pattern for testing aspheric surface and some alignment patterns for aligning the interferometer, CGH, and the test optics. To align the CGH plate and the test optics, we designed the alignment CGHs modified from the cat's eye alignment method, which are consisted of a couple of CGH patterns. The incident beam passed through the one part of the alignment CGH pattern is focused onto the one radius position of the test aspheric surface, and is reflected to the other part, and vice versa. This method has several merits compared to the conventional cat's eye alignment method. First, this method can be used in testing optics with a center hole, and the center part of CGH plate can be assigned to the alignment pattern. Second, the alignment pattern becomes a concentric circular arc pattern. The whole CGH patterns including the main pattern and alignment patterns are consisted of only concentric circular fringes. This concentric circular pattern can be easily made by the polar coordinated writer with circular scanning. The required diffraction angle becomes relatively small, so the 1st order diffraction beams instead of the 3rd order diffraction beam can be used as alignment beams, and the visibility can be improved. This alignment method also is more sensitive to the tilt and the lateral shift of the test aspheric surface. Using this alignment pattern, a 200 mm diameter F/0.5 aspheric mirror and a 600 mm diameter F/0.9 mirror were tested.

  5. Tinting of intraocular lens implants

    Energy Technology Data Exchange (ETDEWEB)

    Zigman, S.

    1982-06-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users.

  6. Tinting of intraocular lens implants

    International Nuclear Information System (INIS)

    Zigman, S.

    1982-01-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users

  7. The Visual Effects of Intraocular Colored Filters

    Directory of Open Access Journals (Sweden)

    Billy R. Hammond

    2012-01-01

    Full Text Available Modern life is associated with a myriad of visual problems, most notably refractive conditions such as myopia. Human ingenuity has addressed such problems using strategies such as spectacle lenses or surgical correction. There are other visual problems, however, that have been present throughout our evolutionary history and are not as easily solved by simply correcting refractive error. These problems include issues like glare disability and discomfort arising from intraocular scatter, photostress with the associated transient loss in vision that arises from short intense light exposures, or the ability to see objects in the distance through a veil of atmospheric haze. One likely biological solution to these more long-standing problems has been the use of colored intraocular filters. Many species, especially diurnal, incorporate chromophores from numerous sources (e.g., often plant pigments called carotenoids into ocular tissues to improve visual performance outdoors. This review summarizes information on the utility of such filters focusing on chromatic filtering by humans.

  8. Gravitational lensing

    CERN Document Server

    Dodelson, Scott

    2017-01-01

    Gravitational lensing is a consequence of general relativity, where the gravitational force due to a massive object bends the paths of light originating from distant objects lying behind it. Using very little general relativity and no higher level mathematics, this text presents the basics of gravitational lensing, focusing on the equations needed to understand the phenomena. It then applies them to a diverse set of topics, including multiply imaged objects, time delays, extrasolar planets, microlensing, cluster masses, galaxy shape measurements, cosmic shear, and lensing of the cosmic microwave background. This approach allows undergraduate students and others to get quickly up to speed on the basics and the important issues. The text will be especially relevant as large surveys such as LSST and Euclid begin to dominate the astronomical landscape. Designed for a one semester course, it is accessible to anyone with two years of undergraduate physics background.

  9. Comparison of hydrophobic and hydrophilic intraocular lens in preventing posterior capsule opacification after cataract surgery

    Science.gov (United States)

    Zhao, Yang; Yang, Ke; Li, Jiaxin; Huang, Yang; Zhu, Siquan

    2017-01-01

    Abstract Background: Posterior capsular opacification (PCO) is a common long-term complication of cataract surgery. Intraocular lens design and material have been implicated in influencing the development of PCO. This study evaluated the association of hydrophobic and hydrophilic intraocular lenses on preventing PCO. Methods: Medline, Cochrane, EMBASE, and Google Scholar databases were searched until August 3, 2016, using the following search terms: cataract, posterior capsule opacification, and intraocular lens. Eligible studies included randomized controlled trials (RCTs), retrospective, and cohort studies. Results: Eleven studies were included in the study with a total of 889 eyes/patients. The overall analysis revealed that hydrophobic intraocular lenses were associated with lower Nd:YAG laser capsulotomy rates than hydrophilic lenses [odds ratio (OR) = 0.38, 95% confidence interval (95% CI) = 0.16–0.91, P = .029]. Hydrophobic intraocular lenses were also associated with lower subjective PCO score (diff. in means: −1.32, 95% CI = −2.39 to −0.25, P = .015) and estimated PCO score (diff. in means: −2.23; 95% CI, −3.80 to −0.68, P = .005) as compared with hydrophilic lenses. Objective PCO score was similar between lens types. (diff. in means: −0.075; 95% CI, −0.18 to 0.035; P = .182). Pooled analysis found that visual acuity was similar between hydrophobic and hydrophilic intraocular lenses (diff. in means: −0.016; 95% CI, −0.041 to 0.009, P = .208). Conclusion: In general, PCO scores and the rate of Nd:YAG laser capsulotomy were influenced by intraocular lens biomaterial. Lens made of hydrophobic biomaterial were overall superior in lowering the PCO score and the Nd:YAG laser capsulotomy rate, but not visual acuity. PMID:29095259

  10. Gabor lenses

    International Nuclear Information System (INIS)

    Mobley, R.M.; Gamml, G.; Maschke, A.W.

    1979-01-01

    Stable operation of Gabor lenses has been reported by at least three experimental groups. At Brookhaven, several lens designs have been tried since February, 1978 with very good results. The lens concept is simple, operation is less complicated than anticipated, and the focussing strengths attainable make them very attractive alternatives to magnetic focussing for heavy ion beams at low energies. Results obtained with five different configurations are presented. The lenses work well, concern is now with fine details of their beam-optical performance

  11. Gravitational lenses

    International Nuclear Information System (INIS)

    Turner, E.L.

    1989-01-01

    The author discusses how gravitational lens studies is becoming a major focus of extragalactic astronomy and cosmology. This review is organized into five parts: an overview of the observational situation, a look at the state of theoretical work on lenses, a detailed look at three recently discovered types of lensing phenomena (luminous arcs, radio rings, quasar-galaxy associations), a review of progress on two old problems in lens studies (deriving unique lens mass distribution models, measurements of differential time delays), and an attempt to look into the future of lens studies

  12. Application of a virtual coordinate measuring machine for measurement uncertainty estimation of aspherical lens parameters

    International Nuclear Information System (INIS)

    Küng, Alain; Meli, Felix; Nicolet, Anaïs; Thalmann, Rudolf

    2014-01-01

    Tactile ultra-precise coordinate measuring machines (CMMs) are very attractive for accurately measuring optical components with high slopes, such as aspheres. The METAS µ-CMM, which exhibits a single point measurement repeatability of a few nanometres, is routinely used for measurement services of microparts, including optical lenses. However, estimating the measurement uncertainty is very demanding. Because of the many combined influencing factors, an analytic determination of the uncertainty of parameters that are obtained by numerical fitting of the measured surface points is almost impossible. The application of numerical simulation (Monte Carlo methods) using a parametric fitting algorithm coupled with a virtual CMM based on a realistic model of the machine errors offers an ideal solution to this complex problem: to each measurement data point, a simulated measurement variation calculated from the numerical model of the METAS µ-CMM is added. Repeated several hundred times, these virtual measurements deliver the statistical data for calculating the probability density function, and thus the measurement uncertainty for each parameter. Additionally, the eventual cross-correlation between parameters can be analyzed. This method can be applied for the calibration and uncertainty estimation of any parameter of the equation representing a geometric element. In this article, we present the numerical simulation model of the METAS µ-CMM and the application of a Monte Carlo method for the uncertainty estimation of measured asphere parameters. (paper)

  13. Anterior corneal profile with variable asphericity.

    Science.gov (United States)

    Rosales, Marco A; Juárez-Aubry, Montserrat; López-Olazagasti, Estela; Ibarra, Jorge; Tepichín, Eduardo

    2009-12-10

    We present a corneal profile in which the eccentricity, e(Q=-e(2)), has a nonlinear continuous variation from the center outwards. This nonlinear variation is intended to fit and reproduce our current experimental data in which the anterior corneal surface of the human eye exhibits different values of e at different diameters. According to our clinical data, the variation is similar to an exponential decay. We propose a linear combination of two exponential functions to describe the variation of e. We then calculate the corneal sagittal height by substituting e in the first-order aspherical surface equation to obtain the corneal profile. This corneal profile will be used as a reference to analyze the resultant profiles of the customized corneal ablation in refractive surgery.

  14. Comparison of PMMA, foldable silicone and foldable acrylic hydrophobic intraocular lenses in combined phacoemulsification and trabeculectomy Comparação entre lentes intra-oculares de PMMA, lentes dobráveis de silicone e lentes acrílicas hidrofóbicas dobráveis em cirurgias combinadas de facoemulsificação e trabeculectomia

    Directory of Open Access Journals (Sweden)

    Ernani Serpa Junior

    2005-02-01

    Full Text Available PURPOSE: To compare the postoperative results of phacotrabeculectomy with implantation of PMMA, foldable silicone or foldable hydrofobic acrylic intraocular lens (IOL. SETTING: Glaucoma unit, The Royal Liverpool University Hospital, Liverpool, United Kingdom. METHODS: We studied a total of 124 eyes of three consecutive groups of patients with glaucoma and cataract that underwent phacotrabeculectomy with implantation of a PMMA (30 eyes, a foldable silicone (57 eyes or a foldable acrylic (37 eyes IOL. Postoperative Snellen visual acuity and intraocular pressure (IOP, and early and late complications were assessed. All data were analyzed by means of c² test, Fisher's exact test, ANOVA/MANOVA tests or a combination whenever appropriate. RESULTS: In all three groups the early and late mean postoperative IOPs were significantly lower than the preoperative ones (p25 mmHg and hypotony (IOPOBJETIVO: Comparar os resultados pós-operatórios de facotrabeculectomias com implante de lentes intra-oculares de PMMA, dobráveis de silicone e acrílicas hidrofóbicas dobráveis. MÉTODOS: Estudo comparativo retrospectivo, realizado no Departamento de Glaucoma da "St. Paul's Eye Unit - The Royal Liverpool University Hospital", em Liverpool, Inglaterra, onde foram estudados um total de 124 olhos de três grupos consecutivos de pacientes com glaucoma e catarata que foram submetidos à cirurgia de facotrabeculectomia com implante de lentes intra-oculares (LIO de PMMA (30 olhos, dobráveis de silicone (57 olhos e acrílicas hidrofóbicas dobráveis (37 olhos. Foram registradas a visão e pressão intra-ocular (PIO pré e pós-operatória, assim como as complicações pós-operatórias precoces e tardias. Todos os dados foram analisados utilizando-se o teste c², teste exato de Fisher, teste de ANOVA/MANOVA ou uma combinação deles quando necessário. RESULTADOS: Nos três grupos as PIOs pós-operatórias precoces e tardias foram significativamente inferiores

  15. Stress analysis of aspherical coated particle with inner pressure

    Energy Technology Data Exchange (ETDEWEB)

    Liu Bing, E-mail: bingliu@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Yang Lin; Liang Tongxiang; Tang Chunhe [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China)

    2012-10-15

    Coated particles used in HTR fuel element sustain the inner pressure during irradiation as a pressure vessel. In actually the coated particle is not real spherical but with some asphericity, the stress distribution in the vessel is not uniform, coated layer in aspherical particle sustain more additional stress due to the asphericity. In this paper, the geometric shape distribution is summarized based on actual coated particle statistic. A mechanical analysis model is proposed for SiC layer by geometric combinations, and stress distribution of coated particle with a flat is calculated. The results show that the local maximum stress of aspherical particle increased two times than that of ideal spherical coated particle, which increase the failure probability under irradiation and high temperature.

  16. Aspherical Dust Envelopes Around Oxygen-Rich AGB Stars

    Directory of Open Access Journals (Sweden)

    Kyung-Won Suh

    2006-12-01

    Full Text Available We model the aspherical dust envelopes around O-rich AGB stars. We perform the radiative transfer model calculations for axisymmetric dust distributions. We simulate what could be observed from the aspherical dust envelopes around O-rich AGB stars by presenting the model spectral energy distributions and images at various wavelengths for different optical depths and viewing angles. The model results are very different from the ones with spherically symmetric geometry.

  17. Comparison of hydrophobic and hydrophilic intraocular lens in preventing posterior capsule opacification after cataract surgery

    OpenAIRE

    Zhao, Yang; Yang, Ke; Li, Jiaxin; Huang, Yang; Zhu, Siquan

    2017-01-01

    Abstract Background: Posterior capsular opacification (PCO) is a common long-term complication of cataract surgery. Intraocular lens design and material have been implicated in influencing the development of PCO. This study evaluated the association of hydrophobic and hydrophilic intraocular lenses on preventing PCO. Methods: Medline, Cochrane, EMBASE, and Google Scholar databases were searched until August 3, 2016, using the following search terms: cataract, posterior capsule opacification, ...

  18. ASPHERICAL SURFACES APPROXIMATION IN AUTOMATED DESIGN OF OPTICAL SYSTEMS

    Directory of Open Access Journals (Sweden)

    T. V. Ivanova

    2015-07-01

    Full Text Available Subject of Research. The paper deals with the problems of higher order aspherical surfaces approximation using different equation types. The objects of research are two types of equations for higher order aspherical surfaces description used in different software for optical systems design (SАRО, OPAL, ZEMAX, CODE-V, etc. and dependent on z-coordinate or on a radial coordinate on the surface. Conversion from one type of equations to another is considered in view of application in different software for optical systems design. Methods. The subject matter of the method lies in usage of mean square method approximation for recalculation of high-order aspherical surface. Iterative algorithm for recalculation is presented giving the possibility to recalculate coefficients for different types of equations with required accuracy. Recommendations are given for choosing recalculation parameters such as the number of result equation coefficients, the number of points for recalculation and point allocation on a surface. Main Results. Example of recalculation for aspherical surface and accuracy estimation, including result aberration comparison between initial surface and recalculated surface are presented. The example has shown that required accuracy of surface representation was obtained. Practical Relevance. This technique is usable for recalculation of higher order aspherical surfaces in various types of software for optical systems design and also for research of optimal higher order aspherical surfaces description.

  19. Measurement of high-departure aspheres using subaperture stitching with the Variable Optical Null (VON)

    Science.gov (United States)

    Kulawiec, Andrew; Murphy, Paul; DeMarco, Michael

    2010-10-01

    Aspheric surfaces are proven to provide significant benefits to a wide variety of optical systems, but the ability to produce high-precision aspheric surfaces has historically been limited by the ability (or lack thereof) to measure them. Traditionally, aspheric measurements have required dedicated null optics, but the cost, lead time, and calibration difficulty of using null optics has made the use of aspheres more challenging and less attractive. In the past three years, QED has developed the Subaperture Stitching Interferometer for Aspheres (SSI-A®) to help address this limitation, providing flexible aspheric measurement capability of up to 200 waves of aspheric departure from best-fit sphere. Some aspheres, however, have thousands of waves of departure. We have recently developed Variable Optical Null (VON) technology that can null much of the aspheric departure in a subaperture. The VON is automatically configurable and is adjusted to nearly null each specific subaperture of an asphere. This ability to nearly null a local subaperture of an asphere provides a significant boost in aspheric measurement capability, enabling aspheres with up to 1000 waves of departure to be measured, without the use of dedicated null optics. We outline the basic principles of subaperture stitching and VON technology, demonstrate the extended capability provided by the VON, and present measurement results from the new Aspheric Stitching Interferometer (ASI®).

  20. CURVAS PARALELAS EXPLÍCITAS DE LAS CURVAS CÓNICAS NO DEGENERADAS PARA EL TORNEADO CNC DE LENTES Y ESPEJOS ASFÉRICO-CÓNICOS EXPLICIT PARALLEL CURVES OF NON-DEGENERATE CONIC CURVES FOR THE TURNED CNC OF ASPHERIC-CONIC LENSES AND MIRORS

    Directory of Open Access Journals (Sweden)

    Juan Camilo Valencia

    2008-12-01

    Full Text Available Este artículo presenta el método para obtener, en coordenadas cartesianas, las líneas curvas paralelas de las curvas cónicas no degeneradas, por métodos analíticos y numéricos. Se define el offset como una función paralela a la función original a una distancia r. El offset de una cónica es importante para los procesos de fabricación de mecanismos, lentes, espejos y moldes; especialmente en el torneado con control numérico computarizado (CNC de superficies de revolución con secciones cónicas, usando buriles de diamante con punta de radio r. También se presenta una técnica refinada usando interpolación circular segmentaria para construir numéricamente el offset de una parábola, que también puede usarse como modelo para determinar el offset de la elipse y de la hipérbola.This paper presents the method to obtain, in Cartesian coordinates, the parallel curve lines of non-degenerate conical curves, by analytical and numerical methods. Offset is defined as parallel function to the original function to a distance r. Offset of a conic is important for the manufacturing processes of mechanisms, lenses, mirrors, and molds; especially in the turning with computerized numerical control (CNC of surfaces of revolution with conical sections, using diamond tools of radio r. Also a refined tip technique using segmental circular interpolation to numerically construct the parabola offset is presented, that also can be used as model to determine offsets of ellipse and hyperbola.

  1. Feasibility assessment of visual quality analyzer KR-1W guiding personalized aspheric IOL implantation

    Directory of Open Access Journals (Sweden)

    Xiao-Li Wang

    2015-01-01

    Full Text Available AIM: To discuss the feasibility of using the visual quality analyzer KR-1W to guide the relatively personalized aspheric intraocular lens(IOLimplants to make the whole eye spherical aberration close to 0.1μm.METHODS: In this prospective case series study, the corneal spherical aberration with 6mm aperture of 73 patients(100 eyeswas measured with KR-1W Visual Function Analyzer 1d before surgery. For the sake of the whole postoperative spherical aberration were close to 0.1μm, 9 cases(16 eyeswith corneal spherical aberration 0.35μm were implanted Tecnis ZA9003 IOL, named Tecnis group. Aspherical IOL was implanted after phacoemulsification through a cornea 2.75mm incision without suture.Uncorrected visual acuity, beat corrected visual acuity, spherical aberration of the whole eye and jnternal optics(mainly IOLat 6mm pupil diameter were examined at 3mo postoperatively. The relevant data were analyzed using t-test and variance analysis.RESULTS: The whole ocular spherical aberration at 6mm pupil diameter in all postoperative were 0.084±0.032μm; in Tecnis group, the data were 0.091 ± 0.021μm; in AO group, the data were 0.0814-0.013μm; IQ group were 0.093±0.042μm. There was no significantly different between the predicted value and actual value of ocular spherical aberration at 6 mm pupil diameter in all postoperative(t=1.932, P=0.061and in the three groups. The difference value in the predicted values of the preoperative spherical aberrations of the whole eye and the actual values after surgery was 0.013±0.041μm; there was no statistically significant difference(F=2.537, P=0.091. Respectively compared the uncorrected visual acuity and besta corrected visual acuity among three groups of postoperative, no significant difference were found(F=0.897, P=0.421; F=1.423, P=0.097.CONCLUSION: Personality selection of aspheric IOL based on preoperative corneal spherical aberration of patients is feasible and produces satisfactory target postoperative

  2. Wavefront measurement of plastic lenses for mobile-phone applications

    Science.gov (United States)

    Huang, Li-Ting; Cheng, Yuan-Chieh; Wang, Chung-Yen; Wang, Pei-Jen

    2016-08-01

    In camera lenses for mobile-phone applications, all lens elements have been designed with aspheric surfaces because of the requirements in minimal total track length of the lenses. Due to the diffraction-limited optics design with precision assembly procedures, element inspection and lens performance measurement have become cumbersome in the production of mobile-phone cameras. Recently, wavefront measurements based on Shack-Hartmann sensors have been successfully implemented on injection-molded plastic lens with aspheric surfaces. However, the applications of wavefront measurement on small-sized plastic lenses have yet to be studied both theoretically and experimentally. In this paper, both an in-house-built and a commercial wavefront measurement system configured on two optics structures have been investigated with measurement of wavefront aberrations on two lens elements from a mobile-phone camera. First, the wet-cell method has been employed for verifications of aberrations due to residual birefringence in an injection-molded lens. Then, two lens elements of a mobile-phone camera with large positive and negative power have been measured with aberrations expressed in Zernike polynomial to illustrate the effectiveness in wavefront measurement for troubleshooting defects in optical performance.

  3. Comparison of hydrophobic and hydrophilic intraocular lens in preventing posterior capsule opacification after cataract surgery: An updated meta-analysis.

    Science.gov (United States)

    Zhao, Yang; Yang, Ke; Li, Jiaxin; Huang, Yang; Zhu, Siquan

    2017-11-01

    Posterior capsular opacification (PCO) is a common long-term complication of cataract surgery. Intraocular lens design and material have been implicated in influencing the development of PCO. This study evaluated the association of hydrophobic and hydrophilic intraocular lenses on preventing PCO. Medline, Cochrane, EMBASE, and Google Scholar databases were searched until August 3, 2016, using the following search terms: cataract, posterior capsule opacification, and intraocular lens. Eligible studies included randomized controlled trials (RCTs), retrospective, and cohort studies. Eleven studies were included in the study with a total of 889 eyes/patients. The overall analysis revealed that hydrophobic intraocular lenses were associated with lower Nd:YAG laser capsulotomy rates than hydrophilic lenses [odds ratio (OR) = 0.38, 95% confidence interval (95% CI) = 0.16-0.91, P = .029]. Hydrophobic intraocular lenses were also associated with lower subjective PCO score (diff. in means: -1.32, 95% CI = -2.39 to -0.25, P = .015) and estimated PCO score (diff. in means: -2.23; 95% CI, -3.80 to -0.68, P = .005) as compared with hydrophilic lenses. Objective PCO score was similar between lens types. (diff. in means: -0.075; 95% CI, -0.18 to 0.035; P = .182). Pooled analysis found that visual acuity was similar between hydrophobic and hydrophilic intraocular lenses (diff. in means: -0.016; 95% CI, -0.041 to 0.009, P = .208). In general, PCO scores and the rate of Nd:YAG laser capsulotomy were influenced by intraocular lens biomaterial. Lens made of hydrophobic biomaterial were overall superior in lowering the PCO score and the Nd:YAG laser capsulotomy rate, but not visual acuity.

  4. Asphere cross testing: an exercise in uncertainty estimation

    Science.gov (United States)

    Murphy, Paul E.

    2017-10-01

    Aspheric surfaces can provide substantial improvements to optical designs, but they can also be difficult to manufacture cost-effectively. Asphere metrology contributes significantly to this difficulty, especially for high-precision aspheric surfaces. With the advent of computer-controlled fabrication machinery, optical surface quality is chiefly limited by the ability to measure it. Consequently, understanding the uncertainty of surface measurements is of great importance for determining what optical surface quality can be achieved. We measured sample aspheres using multiple techniques: profilometry, null interferometry, and subaperture stitching. We also obtained repeatability and reproducibility (R&R) measurement data by retesting the same aspheres under various conditions. We highlight some of the details associated with the different measurement techniques, especially efforts to reduce bias in the null tests via calibration. We compare and contrast the measurement results, and obtain an empirical view of the measurement uncertainty of the different techniques. We found fair agreement in overall surface form among the methods, but meaningful differences in reproducibility and mid-spatial frequency performance.

  5. Theoretical fringe profiles with crossed Babinet compensators in testing concave aspheric surfaces.

    Science.gov (United States)

    Saxena, A K; Lancelot, J P

    1982-11-15

    This paper presents the theory for the use of crossed Babinet compensators in testing concave aspheric surfaces. Theoretical fringe profiles for a sphere and for an aspheric surface with primary aberration are shown. Advantages of this method are discussed.

  6. The effects of two different types of bandage contact lenses on the healthy canine eye.

    Science.gov (United States)

    Braus, Barbara Katharina; Riedler, Daniela; Tichy, Alexander; Spergser, Joachim; Schwendenwein, Ilse

    2018-02-06

    To compare two types of bandage contact lenses on the healthy canine eye. Six healthy Beagles. Two different types of bandage contact lenses (single sized human silicone contact lens 'PureVision 2' (Bausch & Lomb Incorporated, Rochester, NY, USA) and specially designed veterinary hydrogel contact lens 'AcriVet Pat D' (Bausch & Lomb Incorporated) were placed in 12 eyes of healthy Beagle dogs. Retention times and the effects of the lenses regarding irritation of the eye, changes in tear production, impact of contact lenses on tonometric readings, and cytologic and microbiological alterations of the canine eye were investigated. Mean retention times for veterinary hydrogel lenses with special dimensions were significantly shorter (2 days) than for one size human silicon lenses (8.8 days). Irritation scores were overall low for both types of lenses apart from one human lens causing severe irritation and keratoconjunctivitis as a sequel to folding and displacement. Tear production remained stable in human contact lenses. Intraocular pressure readings with a contact lens in place were only slightly altered; the most accurate readings were obtained through a human lens with an applanation tonometer. Cytology revealed a slight, nonsignificant increase in neutrophilic granulocytes with both types of lenses; the microflora did not change significantly. Human silicone lenses have significantly longer retention times and are less expensive than veterinary hydrogel lenses. In regard to irritation, bacterial growth and inflammation, both types of lenses can be recommended for use in canine eyes. © 2018 American College of Veterinary Ophthalmologists.

  7. Comparison of asphere measurements by tactile and optical metrological instruments

    NARCIS (Netherlands)

    Bergmans, R.H.; Nieuwenkamp, H.J.; Kok, G.J.P.; Blobel, G.; Nouira, H.; Küng, A.; Baas, M.; Voert, M.J.A. te; Baer, G.; Stuerwald, S.

    2015-01-01

    A comparison of topography measurements of aspherical surfaces was carried out by European metrology institutes, other research institutes and a company as part of an European metrology research project. In this paper the results of this comparison are presented. Two artefacts were circulated, a

  8. Computer numeric control subaperture aspheric surface polishing—microroughness evaluation

    Czech Academy of Sciences Publication Activity Database

    Procháska, František; Polák, Jaroslav; Matoušek, O.; Tomka, David

    2014-01-01

    Roč. 53, č. 9 (2014), 092011-092011 ISSN 0091-3286 R&D Projects: GA MŠk(CZ) ED2.1.00/03.0079 Institutional support: RVO:61389021 Keywords : aspheric polishing * optic surface microroughness evaluation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.954, year: 2014 http://opticalengineering.spiedigitallibrary.org/article.aspx?articleid=1901511

  9. Quantitative test for concave aspheric surfaces using a Babinet compensator.

    Science.gov (United States)

    Saxena, A K

    1979-08-15

    A quantitative test for the evaluation of surface figures of concave aspheric surfaces using a Babinet compensator is reported. A theoretical estimate of the sensitivity is 0.002lambda for a minimum detectable phase change of 2 pi x 10(-3) rad over a segment length of 1.0 cm.

  10. IOL Implants: Lens Replacement and Cataract Surgery (Intraocular Lenses)

    Science.gov (United States)

    ... Oncology Oculoplastics/Orbit Refractive Management/Intervention Retina/Vitreous Uveitis Focus On Pediatric Ophthalmology ... Are Cataracts? Pediatric Cataracts Cataract Diagnosis and Treatment Cataract Surgery IOL Implants: Lens Replacement After Cataracts ...

  11. Optical quality of hyperopic and myopic phakic intraocular lenses

    Directory of Open Access Journals (Sweden)

    Cari Pérez-Vives

    2014-01-01

    Full Text Available Aims: To assess and compare the optical quality of the myopic and hyperopic implantable collamer lens (ICL from its wavefront aberrations for different powers and pupil diameters. Settings and Design: Prospective study. Material and Methods: The wavefront aberrations of two myopic (−3 and −6 diopters (D and two hyperopic V4b ICLs (+3 and +6D were measured in vitro. To assess and compare the optical quality of different powers of ICLs, we analyzed the root mean square (RMS of total higher order aberrations (HOAs, trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration at 3- and 4.5-mm pupil. In addition, the point spread functions (PSFs of each ICL evaluated were calculated from the wavefront aberrations at 3- and 4.5-mm pupil. Statistical Analysis: A Student′s t-test for unpaired data was used for comparison between myopic and hyperopic ICLs. Results: Myopic ICLs showed negative spherical aberration, in contrast hyperopic ICLs showed positive spherical aberration, which increases when the ICL power increases, due to the innate optical properties of the lens. All ICLs evaluated had negligible amounts of other aberrations. We did not find statistical significant differences in any Zernike coefficient RMS values analyzed between myopic and hyperopic ICLs at 3- and 4.5-mm pupil (P > 0.05. Conclusions: Myopic and hyperopic ICLs provide good and comparable optical quality for low to moderate refractive error. The ICLs evaluated showed values of wavefront aberrations clinically negligible to affect the visual quality after implantation.

  12. MANAGEMENT OF POSTERIOR DISLOCATED INTRAOCULAR LENSES IN A TERTIARY HOSPITAL

    OpenAIRE

    Shashidhar; Apoorva Mithrananda; Manasa Penumetcha; Shruthi Chandra

    2016-01-01

    BACKGROUND The aim of this study was to assess and compare the visual outcome of different approaches in the management of dislocated PCIOL. MATERIALS AND METHODS 20 eyes of 20 patients who underwent 3PPPV/anterior vitrectomy to refixate or IOL exchange for dislocation or subluxation of PCIOL from 2012 to 2015. SFIOLs were implanted in 12 patients, IOL refixation was done in four patients and four were left aphakic. This is a retrospective study of 20 eyes of 20 patients ...

  13. MANAGEMENT OF POSTERIOR DISLOCATED INTRAOCULAR LENSES IN A TERTIARY HOSPITAL

    Directory of Open Access Journals (Sweden)

    Shashidhar

    2016-10-01

    Full Text Available BACKGROUND The aim of this study was to assess and compare the visual outcome of different approaches in the management of dislocated PCIOL. MATERIALS AND METHODS 20 eyes of 20 patients who underwent 3PPPV/anterior vitrectomy to refixate or IOL exchange for dislocation or subluxation of PCIOL from 2012 to 2015. SFIOLs were implanted in 12 patients, IOL refixation was done in four patients and four were left aphakic. This is a retrospective study of 20 eyes of 20 patients with dislocated/subluxated PCIOLs in a tertiary hospital from 2012 to 2015. STATISTICAL ANALYSIS Paired t-test statistical method. RESULTS We retrospectively analysed hospital records of patients who had undergone three PPPV/anterior vitrectomy for posteriorly dislocated/subluxated IOLs 20 eyes of 20 patients were analysed. SFIOLs were implanted in 12 patients, IOL refixation was done in four patients and four were left aphakic. Postoperative BCVA of 6/12 or better was achieved in 66.67% in primary SFIOL, secondary SFIOL and IOL refixation groups. BCVA of <6/60 was seen in all patients left aphakic. Early and late complications were most in aphakic patients. IOL refixation procedure had minimum early and late complications. Subluxated PCIOLs do better than dislocated lens where a successful SFIOL was placed. CONCLUSION IOL refixation procedure has the least complication rate. Early complications of SFIOL management resolve with time. Thus, 3PPPV/anterior vitrectomy with SFIOL and IOL refixation procedures offer a novel approach towards visual rehabilitation of patients with subluxated or dislocated PCIOLs.

  14. Visual and Refractive Outcomes after Cataract Surgery with Implantation of a New Toric Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Cinzia Mazzini

    2013-06-01

    Full Text Available Purpose: The aim of this study was to evaluate and report the visual, refractive and aberrometric outcomes of cataract surgery with implantation of the new aspheric Tecnis ZCT toric intraocular lens (IOL in eyes with low to moderate corneal astigmatism. Methods: We conducted a prospective study of 19 consecutive eyes of 17 patients (mean age: 78 years with a visually significant cataract and moderate corneal astigmatism [higher than 1 diopter (D] undergoing cataract surgery with implantation of the aspheric Tecnis ZCT toric IOL (Abbott Medical Optics. Visual, refractive and aberrometric changes were evaluated during a 6-month follow-up. Ocular aberrations as well as IOL rotation were evaluated by means of the OPD-Station II (Nidek. Results: The six-month postoperative spherical equivalent and power vector components of the refractive cylinder were within ±0.50 D in all eyes (100%. Postoperative logMAR uncorrected and corrected distance visual acuities (UDVA/CDVA were 0.1 (about 20/25 or better in almost all eyes (94.74%. The mean logMAR CDVA improved significantly from 0.41 ± 0.23 to 0.02 ± 0.05 (p Conclusion: Cataract surgery with implantation of the aspheric Tecnis ZCT IOL is a predictable and effective procedure for visual rehabilitation in eyes with cataract and low to moderate corneal astigmatism, providing an excellent postoperative ocular optical quality.

  15. Flurbiprofen and intraocular pressure.

    Science.gov (United States)

    Gieser, D K; Hodapp, E; Goldberg, I; Kass, M A; Becker, B

    1981-07-01

    Systemic or topical administration of corticosteroids may produce a rise in intraocular pressure (IOP). Nonsteroidal anti-inflammatory drugs (NSAI drugs) are alternate therapy for ocular inflammatory disease. Flurbiprofen, a new NSAI drug, was tested in double-masked fashion to delineate its effect on IOP. Flurbiprofen did not alter IOP in known high corticosteroid responders nor did it block corticosteroid-induced ocular hypertension.

  16. Microscopic and spectroscopic investigation of an explanted opacified intraocular lens

    Energy Technology Data Exchange (ETDEWEB)

    Simon, V., E-mail: viosimon@phys.ubbcluj.ro [Babeş-Bolyai University, Faculty of Physics and Interdisciplinary Research Institute on Bio-Nano-Sciences, 400084 Cluj-Napoca (Romania); Radu, T.; Vulpoi, A. [Babeş-Bolyai University, Faculty of Physics and Interdisciplinary Research Institute on Bio-Nano-Sciences, 400084 Cluj-Napoca (Romania); Rosca, C. [Optilens Clinic of Ophthalmology, 400604 Cluj-Napoca (Romania); Eniu, D. [Iuliu Haţieganu University of Medicine and Pharmacy, Department of Molecular Sciences, 400349 Cluj-Napoca (Romania)

    2015-01-15

    Highlights: • Changes on intraocular lens (IOL) surface after implantation. • Partial opacification of IOL central area. • Elemental composition on IOL surface prior to and after implantation. • First XPS depth profiling examination of the opacifying deposits. • Cell-mediated hydroxyapatite structuring. - Abstract: The investigated polymethylmethacrylate intraocular lens explanted an year after implantation presented a fine granularity consisting of ring-like grains of about 15 μm in diameter. In order to evidence the changes occurred on intraocular lens relative to morphology, elemental composition and atomic environments, microscopic and spectroscopic analyses were carried out using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), energy-dispersive X-ray (EDS), and X-ray photoelectron (XPS) spectroscopies. The results revealed that the grains contain hydroxyapatite mineral phase. A protein layer covers the lens both in opacified and transparent zones. The amide II band is like in basal epithelial cells. The shape and size of the grains, and the XPS depth profiling results indicate the possibility of a cell-mediated process involving lens epithelial cells which fagocitated apoptotic epithelial cells, and in which the debris derived from cell necrosis were calcified. To the best of our knowledge, this is the first investigation on explanted intraocular lenses using XPS depth profiling in order to examine the inside of the opacifying deposits.

  17. New trends in intraocular lens imaging

    Science.gov (United States)

    Millán, María S.; Alba-Bueno, Francisco; Vega, Fidel

    2011-08-01

    As a result of modern technological advances, cataract surgery can be seen as not only a rehabilitative operation, but a customized procedure to compensate for important sources of image degradation in the visual system of a patient, such as defocus and some aberrations. With the development of new materials, instruments and surgical techniques in ophthalmology, great progress has been achieved in the imaging capability of a pseudophakic eye implanted with an intraocular lens (IOL). From the very beginning, optical design has played an essential role in this progress. New IOL designs need, on the one hand, theoretical eye models able to predict optical imaging performance and on the other hand, testing methods, verification through in vitro and in vivo measurements, and clinical validation. The implant of an IOL requires a precise biometry of the eye, a prior calculation from physiological data, and an accurate position inside the eye. Otherwise, the effects of IOL calculation errors or misplacements degrade the image very quickly. The incorporation of wavefront aberrometry into clinical ophthalmology practice has motivated new designs of IOLs to compensate for high order aberrations in some extent. Thus, for instance, IOLs with an aspheric design have the potential to improve optical performance and contrast sensitivity by reducing the positive spherical aberration of human cornea. Monofocal IOLs cause a complete loss of accommodation that requires further correction for either distance or near vision. Multifocal IOLs address this limitation using the principle of simultaneous vision. Some multifocal IOLs include a diffractive zone that covers the aperture in part or totally. Reduced image contrast and undesired visual phenomena, such as halos and glare, have been associated to the performance of multifocal IOLs. Based on a different principle, accommodating IOLs rely on the effort of the ciliary body to increase the effective power of the optical system of the

  18. Intraocular (Eye) Melanoma—Health Professional Version

    Science.gov (United States)

    Intraocular (uveal) melanoma of the uveal tract (iris, ciliary body, and choroid), though rare, is the most common primary intraocular malignancy in adults. Find evidence-based information on intraocular melanoma treatment.

  19. Surface topography of parallel grinding process for nonaxisymmetric aspheric lens

    International Nuclear Information System (INIS)

    Zhang Ningning; Wang Zhenzhong; Pan Ri; Wang Chunjin; Guo Yinbiao

    2012-01-01

    Workpiece surface profile, texture and roughness can be predicted by modeling the topography of wheel surface and modeling kinematics of grinding process, which compose an important part of precision grinding process theory. Parallel grinding technology is an important method for nonaxisymmetric aspheric lens machining, but there is few report on relevant simulation. In this paper, a simulation method based on parallel grinding for precision machining of aspheric lens is proposed. The method combines modeling the random surface of wheel and modeling the single grain track based on arc wheel contact points. Then, a mathematical algorithm for surface topography is proposed and applied in conditions of different machining parameters. The consistence between the results of simulation and test proves that the algorithm is correct and efficient. (authors)

  20. Optical description and design method with annularly stitched aspheric surface.

    Science.gov (United States)

    Cheng, De-Wen; Chen, Xue-Jiao; Xu, Chen; Hu, Yuan; Wang, Yong-Tian

    2015-12-01

    The relentless pressure for designs with new optical functions, small volume, and light weight has greatly increased the importance of aspheric surfaces. In this paper, we propose an annularly stitched aspheric surface (ASAS) description method to increase the freedom and flexibility of imaging system design. The rotationally symmetric ASAS consists of a circular central zone and one or more annular zones. Two neighboring zones are constrained to have the same derivatives on their joint curve, and this means the ASAS is C1 continuous. This finding is proved and verified by the mathematical deduction of the surface formulas. Two optimization strategies and two design methods with the C1 continuous constraints are also discussed. This surface can greatly facilitate the design and even achieve some previously impossible designs without increasing the fabrication difficulty. Two different systems with the proposed ASAS are optimized and the results are presented. The design results verified the practicability of the ASAS.

  1. Active optics: off axis aspherics generation for high contrast imaging

    Science.gov (United States)

    Hugot, E.; Laslandes, M.; Ferrari, M.; Vives, S.; Moindrot, S.; El Hadi, K.; Dohlen, K.

    2017-11-01

    Active Optics methods, based on elasticity theory, allow the aspherisation of optical surfaces by stress polishing but also active aspherisation in situ. Researches in this field will impact the final performance and the final cost of any telescope or instrument. The stress polishing method is well suited for the superpolishing of aspheric components for astronomy. Its principle relies on spherical polishing with a full-sized tool of a warped substrate, which becomes aspherical once unwarped. The main advantage of this technique is the very high optical quality obtained either on form or on high spatial frequency errors. Furthermore, the roughness can be decreased down to a few angstroms, thanks the classical polishing with a large pitch tool, providing a substantial gain on the final scientific performance, for instance on the contrast on coronagraphic images, but also on the polishing time and cost. Stress polishing is based on elasticity theory, and requires an optimised deformation system able to provide the right aspherical form on the optical surface during polishing. The optical quality of the deformation is validated using extensive Finite Element Analysis, allowing an estimation of residuals and an optimisation of the warping harness. We describe here the work realised on stress polishing of toric mirrors for VLT-SPHERE and then our actual work on off axis aspherics (OAA) for the ASPIICS-Proba3 mission for solar coronagraphy. The ASPIICS optical design made by Vives et al is a three mirrors anastigmat including a concave off axis hyperboloid and a convex off axis parabola (OAP). We are developing a prototype in order to demonstrate the feasibility of this type of surface, using a multi-mode warping harness (Lemaitre et al). Furthermore, we present our work on variable OAP, meaning the possibility to adjust the shape of a simple OAP in situ with a minimal number of actuators, typically one actuator per optical mode (Focus, Coma and Astigmatism

  2. On asphericity of convex bodies in linear normed spaces.

    Science.gov (United States)

    Faried, Nashat; Morsy, Ahmed; Hussein, Aya M

    2018-01-01

    In 1960, Dvoretzky proved that in any infinite dimensional Banach space X and for any [Formula: see text] there exists a subspace L of X of arbitrary large dimension ϵ -iometric to Euclidean space. A main tool in proving this deep result was some results concerning asphericity of convex bodies. In this work, we introduce a simple technique and rigorous formulas to facilitate calculating the asphericity for each set that has a nonempty boundary set with respect to the flat space generated by it. We also give a formula to determine the center and the radius of the smallest ball containing a nonempty nonsingleton set K in a linear normed space, and the center and the radius of the largest ball contained in it provided that K has a nonempty boundary set with respect to the flat space generated by it. As an application we give lower and upper estimations for the asphericity of infinite and finite cross products of these sets in certain spaces, respectively.

  3. Fiscal 2000 achievement report on the venture business assisting type regional consortium - Core industry creation type. Research and development of high-accuracy fabrication technology of aspheric optical component creation technology using parallel grinding method; 2000 nendo chiiki consortium kenkyu kaihatsu jigyo seika hokokusho. Parallel kensaku hoshiki ni yoru koseido hikyumen kogaku soshi sosei gijutsu no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Research and development was carried out for the establishment and commercialization of the technical seeds of a newly proposed 'parallel grinding type aspheric surface grinding method,' based on the results of studies of ultra-accuracy grinding and aspheric surface machining technologies conducted at Tohoku University. The new method is characterized in that a work point on the work piece faces the grinding point on the grindstone cross section on the one-to-one basis because the grinding point travels on the grindstone cross section. Accordingly, the method is quite suitable for corrective grinding for eliminating only the error in case a geometrical error occurs on the wrought surface. For this purpose, measurement of the machine surface on board the machine is indispensable. Hence: a study of corrective grinding methods under an on-board measuring system. As the result, the initially intended geometrical accuracy level was attained in the machining of axis-symmetric aspheric glass lenses and aspheric metal molds, and coarseness on the finished surface in the grinding of glass lenses was reduced to 0.3{mu}m using a diamond grindstone. In conclusion, machining accuracy and finished surface coarseness were remarkably improved, and this enables machining without the need of polishing and demonstrates that there are possibilities of commercialization. (NEDO)

  4. Spectral properties of common intraocular lens (IOL) types

    Science.gov (United States)

    Milne, Peter J.; Chapon, Pascal F.; Hamaoui, Marie; Parel, Jean-Marie A.; Clayman, H.; Rol, Pascal O.

    1999-06-01

    Currently over 50 kinds of intraocular lenses (IOLs) are approved for patient use in the treatment of cataracts and ametropia. These lenses are manufactured from at least 2 kinds of silicones as well as several kinds of acrylic polymers including polyHEMA, Poly HOXEMA, a range of polymethacrylate and polyacrylate formulations. We sought to measure spectral transmission curves of a range of IOLS in the UV-visible and near IR spectral regions in order to better characterize their optical properties and to provide a baseline from which to assess their alteration following implantation over time. Consideration of how this may best be achieved are discussed. The variable ability of both explained IOLs and some samples from a range of manufacturers to block UV wavelengths is commented upon.

  5. Preliminary study of the correlation between refractive error and corneal refractive power, corneal asphericity in myopic eye

    Directory of Open Access Journals (Sweden)

    Qi-Chao Han

    2014-05-01

    Full Text Available AIM: To investigate the correlation between myopic refractive error and relative factors, including the corneal refractive power, posterior refractive power, axial length, corneal asphericity coefficient Q value, central cornea thickness(CCTand intraocular pressure(IOP. METHODS:According to the degree of myopia measured by subjective refraction, 138 myopia patients were divided into three subgroups: mild group(-1.00D--3.00D, moderate group(-3.25D--6.00D, high group(>6.00D. The Pentacam anterior segment tomographer(Germany, Oculus Companywas used to measure the corneal refractive power, posterior refractive power, and corneal asphericity in the right eye. IOP, CCT and axial length were measured by a non-contact tonometer and A-scan ultrasonic, respectively. The data was analyzed with a Pearson correlation analysis and one-way ANOVA. RESULTS: The myopic refractive error was negatively correlated with the axial length(r=-0.682, Pr=0.009, P=0.925. The axial length was negatively correlated with corneal refractive power(r=-0.554, Pr=0.674, Pr=-0.375, P=0.01. There was no significantly correlation between the myopic refractive error and CCT, IOP(r=-0.138, P=0.141; r=-0.121, P=0.157. CONCLUSION:The corneal refractive power plays the role of emmetropization during the development of myopia. There is clinic significance for the correlation between Q value and refractive error, IOP to guide the corneal refractive surgery.

  6. Toric Intraocular Lens Outcomes in Patients With Glaucoma.

    Science.gov (United States)

    Brown, Reay H; Zhong, Le; Bozeman, Caroline W; Lynch, Mary G

    2015-06-01

    To report the outcomes of toric intraocular lens implantation in patients with glaucoma and corneal astigmatism. One hundred twenty-six eyes of 87 patients with glaucoma and corneal astigmatism that underwent cataract surgery with an AcrySof toric intraocular lens (Alcon Laboratories, Inc., Fort Worth, TX) implant were selected for this single-center, retrospective case series. Corrected distance visual acuity, intraocular pressure, and refractive astigmatism were measured in each eye preoperatively and postoperatively. Uncorrected distance visual acuity and toric alignment were measured postoperatively. The uncorrected distance visual acuity was 0.04 ± 0.08 logMAR (20/22 Snellen) for all eyes. Ninety-eight percent of all eyes achieved an uncorrected distance visual acuity of 20/40 or better, with 76% achieving 20/25 or better and 47% achieving 20/20. The corrected distance visual acuity for all eyes was 0.01 ± 0.03 logMAR (20/20.5 Snellen) postoperatively. The refractive cylinder improved from 1.47 ± 1.10 diopters preoperatively to 0.31 ± 0.37 diopters postoperatively. The residual refractive cylinder was 1.00 diopter or less in 97% of eyes, 0.75 diopters or less in 90% of eyes, and 0.50 diopters or less in 83% of eyes. Mean misalignment was 4.4° ± 5.1°. Intraocular pressure decreased by a mean of 2.3 ± 3.3 mm Hg following the surgery. Toric intraocular lenses can reliably reduce astigmatism and improve uncorrected vision in eyes with cataract and glaucoma. Copyright 2015, SLACK Incorporated.

  7. Intraocular pressure reduction and regulation system

    Science.gov (United States)

    Baehr, E. F.; Burnett, J. E.; Felder, S. F.; Mcgannon, W. J.

    1979-01-01

    An intraocular pressure reduction and regulation system is described and data are presented covering performance in: (1) reducing intraocular pressure to a preselected value, (2) maintaining a set minimum intraocular pressure, and (3) reducing the dynamic increases in intraocular pressure resulting from external loads applied to the eye.

  8. SU-8 Lenses: Simple Methods of Fabrication and Application in Optical Interconnection Between Fiber/LED and Microstructures

    Science.gov (United States)

    Nguyen, Minh-Hang; Nguyen, Hai-Binh; Nguyen, Tuan-Hung; Vu, Xuan-Manh; Lai, Jain-Ren; Tseng, Fan-Gang; Chen, Te-Chang; Lee, Ming-Chang

    2016-05-01

    This paper presents two facile methods to fabricate off-plane lenses made of SU-8, an epoxy-based negative photoresist from MicroChem, on glass for optical interconnection. The methods allow the fabrication of lenses with flexible spot size and focal length depending on SU-8 well size and SU-8 drop volume and viscosity. In the first method, SU-8 drops were applied directly into patterned SU-8 wells with Teflon-coated micropipettes, and were baked to become (a)-spherical lenses. The lens shape and size were mainly determined by SU-8 viscosity, ratio of drop volume to well volume, and baking temperature and time. In the second method, a glass substrate with SU-8 patterned wells was emerged in diluted SU-8, then drawn up and baked to form lenses. The lens shapes and sizes were mainly determined by SU-8 viscosity and well volume. By the two methods, SU-8 lenses were successfully fabricated with spot sizes varying in range from micrometers to hundred micrometers, and focal lengths varying in range of several millimeters, depending on the lens rim diameters and aspheric sag height. Besides, on-plane SU-8 lenses were fabricated by photolithography to work in conjunction with the off-plane SU-8 lenses. The cascaded lenses produced light spots reduced to several micrometers, and they can be applied as a coupler for light coupling from fiber/Light-emitting diode (LED) to microstructures and nanostructures. The results open up the path for fabricating novel optical microsystems for optical communication and optical sensing applications.

  9. Corneal edema and permanent blue discoloration of a silicone intraocular lens by methylene blue.

    Science.gov (United States)

    Stevens, Scott; Werner, Liliana; Mamalis, Nick

    2007-01-01

    To report a silicone intraocular lens (IOL) stained blue by inadvertent intraoperative use of methylene blue instead of trypan blue and the results of experimental staining of various lens materials with different concentrations of the same dye. A "blue dye" was used to enhance visualization during capsulorhexis in a patient undergoing phacoemulsification with implantation of a three-piece silicone lens. Postoperatively, the patient presented with corneal edema and a discolored IOL. Various IOL materials were experimentally stained using methylene blue. Sixteen lenses (4 silicone, 4 hydrophobic acrylic, 4 hydrophilic acrylic, and 4 polymethylmethacrylate) were immersed in 0.5 mL of methylene blue at concentrations of 1%, 0.1%, 0.01%, and 0.001%. These lenses were grossly and microscopically evaluated for discoloration 6 and 24 hours after immersion. The corneal edema resolved within 1 month after the initial surgical procedure. After explantation, gross and microscopic analyses of the explanted silicone lens revealed that its surface and internal substance had been permanently stained blue. In the experimental study, all of the lenses except the polymethylmethacrylate lenses were permanently stained by methylene blue. The hydrophilic acrylic lenses showed the most intense blue staining in all dye concentrations. This is the first clinicopathological report of IOL discoloration due to intraocular use of methylene blue. This and other tissue dyes may be commonly found among surgical supplies in the operating room and due diligence is necessary to avoid mistaking these dyes for those commonly used during ocular surgery.

  10. Descriptive analysis of the type and design of contact lenses fitted according to keratoconus severity and morphology

    Directory of Open Access Journals (Sweden)

    Letícia Helena Lunardi

    2016-04-01

    Full Text Available ABSTRACT Purpose: Keratoconus is characterized by bilateral asymmetrical corneal ectasia that leads to inferior stromal thinning and corneal protrusion. There is currently a lack of consensus regarding the most efficacious method for fitting contact lenses in patients with keratoconus, given the various topographical patterns and evolution grades observed in affected populations. The purpose of the present study was to evaluate the association between keratoconus evolution grade and topography pattern and the type and design of fitted contact lens. Methods: We performed a retrospective analysis of contact lenses fitted in a total of 185 patients with keratoconus (325 eyes. Keratoconus was classified as either grade I, II, III, or IV based on keratometry and cone morphology (nipple, oval, globus, or indeterminate results. Results: A total of 325 eyes were evaluated in the present study. Of the 62 eyes classified as grade I, 66.1% were fitted with monocurve contact lenses. Of the 162 eyes classified as grade I and II, 51%, 30%, and 19% were fitted with adapted monocurve rigid gas-permeable contact lenses (RGPCL, bicurve lenses, and others lens types, respectively. Bicurve lenses were fitted in 52.1% and 62.2% of eyes classified as grade III and IV, respectively. Of the eyes classified as grade III and IV, monocurve and bicurve RGPCL were fitted in 26% and 55%, respectively. In eyes with oval keratoconus, 45%, 35%, and 20% were fitted with monocurve lenses, bicurve lenses, and other lens types, respectively. In eyes with round cones (nipple morphology, 55%, 30%, and 15% were fitted with bicurve lenses, monocurve lenses, and other lens types, respectively. Conclusion: Monocurve RGPCL were most frequently fitted in patients with mild to moderate keratoconus and oval cones morphology, while bicurve lenses were more frequently fitted in patients with severe and advanced keratoconus. This was probably because bicurve lenses are more appropriate for

  11. One Episode, Two Lenses

    Science.gov (United States)

    Drijvers, Paul; Godino, Juan D.; Font, Vicenc; Trouche, Luc

    2013-01-01

    A deep understanding of students' learning processes is one of the core challenges of research in mathematics education. To achieve this, different theoretical lenses are available. The question is how these different lenses compare and contrast, and how they can be coordinated and combined to provide a more comprehensive view on the topic of…

  12. Improved illumination system of laparoscopes using an aspherical lens array.

    Science.gov (United States)

    Wu, Rengmao; Qin, Yi; Hua, Hong

    2016-06-01

    The current fiber-based illumination systems of laparoscopes are unable to uniformly illuminate a large enough area in abdomen due to the limited numerical aperture (NA) of the fiber bundle. Most energy is concentrated in a small region at the center of the illumination area. This limitation becomes problematic in laparoscopes which require capturing a wide field of view. In this paper, we propose an aspherical lens array which is used to direct the outgoing rays from the fiber bundle of laparoscope to produce a more uniformly illuminated, substantially larger field coverage than standalone fiber source. An intensity feedback method is developed to design the aspherical lens unit for extended non-Lambertian sources, which is the key to the design of this lens array. By this method, the lens unit is obtained after only one iteration, and the lens array is constructed by Boolean operation. Then, the ray-tracing technique is used to verify the design. Further, the lens array is fabricated and experimental tests are performed. The results clearly show that the well-illuminated area is increased to about 0.107m(2) from 0.02m(2) (about 5x larger than a standard fiber illumination source). More details of the internal organs can be clearly observed under this improved illumination condition, which also reflects the significant improvement in the optical performance of the laparoscope.

  13. Implementation of Bluetooth technology in processing aspheric mirrors

    Science.gov (United States)

    Chen, Dong-yun; Li, Xiao-jin

    2010-10-01

    This paper adopts the Bluetooth wireless transmission to replace the conducting rings currently using in the active lap process to overcome the cost and abrasion problems brought by the conducting rings, which has great significance for reducing the costs of processing large aspheric mirrors. Based on the actual application requirements, Article proposes the overall program of using Bluetooth technology as data transmission, including the active lap-side and machine tool-side: In the machine tool-side, the MCU separately connects with Bluetooth module and the sensor via UART0 and UART1 serial port, and when the MCU receives the signals sending from the sensor, the MCU packs and then sends them through the Bluetooth module; while in the active lap side, the CCAL reads-out the position signals of sensor detecting in dual-port memory via one-side ports, and the other side ports connect with the MCU's high ports P4-P7, so the MCU can unpacks and stores the position signals receiving via Bluetooth module. This paper designs and implements the system's hardware circuit, and mainly introduces the ways of serial and parallel. Based upon the realized system, design the test program for the Bluetooth wireless transmission and the experiment results, in the condition of the active lap processing large aspheric mirrors, showed that Bluetooth technology can meet the requirements of practical applications.

  14. Intraocular inflammation in autoimmune diseases.

    Science.gov (United States)

    Pras, Eran; Neumann, Ron; Zandman-Goddard, Gisele; Levy, Yair; Assia, Ehud I; Shoenfeld, Yehuda; Langevitz, Pnina

    2004-12-01

    The uveal tract represents the vascular organ of the eye. In addition to providing most of the blood supply to the intraocular structures, it acts as a conduit for immune cells, particularly lymphocytes, to enter the eye. Consequently, the uveal tract is represented in many intraocular inflammatory processes. Uveitis is probably a misnomer unless antigens within the uvea are the direct targets of the inflammatory process. A better term of the condition is "intraocular inflammation" (IOI). To review the presence of IOI in autoimmune diseases, the immunopathogenic mechanisms leading to disease, and treatment. We reviewed the English medical literature by using MEDLINE (1984-2003) employing the terms "uveitis," "intraocular inflammation," and "autoimmune diseases." An underlying autoimmune disease was identified in up to 40% of patients with IOI, and included spondyloarthropathies, Behcets disease, sarcoidosis, juvenile chronic arthritis, Vogt-Koyanagi-Harada syndrome (an inflammatory syndrome including uveitis with dermatologic and neurologic manifestations), immune recovery syndrome, and uveitis with tubulointerstitial disease. The immunopathogenesis of IOI involves enhanced T-cell response. Recently, guidelines for the use of immunosuppressive drugs for inflammatory eye disease were established and include: corticosteroids, azathioprine, methotrexate, mycophenolate mofetil, cyclosporine, tacrolimus, cyclophosphamide, and chlorambucil. New therapies with limited experience include the tumor necrosis factor alpha inhibitors, interferon alfa, monoclonal antibodies against lymphocyte surface antigens, intravenous immunoglobulin (IVIG), and the intraocular delivery of immunosuppressive agents. An underlying autoimmune disease was identified in up to 40% of patients with IOI. Immunosuppressive drugs, biologic agents, and IVIG are employed for the treatment of IOI in autoimmune diseases.

  15. Gravitational lensing of quasars

    CERN Document Server

    Eigenbrod, Alexander

    2013-01-01

    The universe, in all its richness, diversity and complexity, is populated by a myriad of intriguing celestial objects. Among the most exotic of them are gravitationally lensed quasars. A quasar is an extremely bright nucleus of a galaxy, and when such an object is gravitationally lensed, multiple images of the quasar are produced – this phenomenon of cosmic mirage can provide invaluable insights on burning questions, such as the nature of dark matter and dark energy. After presenting the basics of modern cosmology, the book describes active galactic nuclei, the theory of gravitational lensing, and presents a particular numerical technique to improve the resolution of astronomical data. The book then enters the heart of the subject with the description of important applications of gravitational lensing of quasars, such as the measurement of the famous Hubble constant, the determination of the dark matter distribution in galaxies, and the observation of the mysterious inner parts of quasars with much higher r...

  16. Weakly oval electron lense

    International Nuclear Information System (INIS)

    Daumenov, T.D.; Alizarovskaya, I.M.; Khizirova, M.A.

    2001-01-01

    The method of the weakly oval electrical field getting generated by the axially-symmetrical field is shown. Such system may be designed with help of the cylindric form coaxial electrodes with the built-in quadrupole duplet. The singularity of the indicated weakly oval lense consists of that it provides the conducting both mechanical and electronic adjustment. Such lense can be useful for elimination of the near-axis astigmatism in the electron-optical system

  17. Role of short-wavelength filtering lenses in delaying myopia progression and amelioration of asthenopia in juveniles

    Directory of Open Access Journals (Sweden)

    Hai-Lan Zhao

    2017-08-01

    Full Text Available AIM: To evaluate the positive effects of blue-violet light filtering lenses in delaying myopia and relieving asthenopia in juveniles. METHODS: Sixty ametropia juveniles (aged range, 11-15y were randomized into two groups: the test group (30 children, 60 eyes, wearing blue-violet light filtering lenses; and the control group (30 children, 60 eyes, wearing ordinary aspherical lenses. Baseline refractive power of the affected eyes and axial length of the two groups was recorded. After 1-year, the patients underwent contrast sensitivity (glare and non-glare under bright and dark conditions, accommodation-related testing, asthenopia questionnaire assessment, and adverse reaction questionnaire assessment. RESULTS: After 1y of wearing the filtering lenses, changes in refractive power and axial length were not significantly different between the two groups (P>0.05. Under bright conditions, the contrast sensitivities at low and medium-frequency grating (vision angles of 6.3°, 4.0°, and 2.5° with glare in the test group were significantly higher than in the control group (P0.05. In the test group, the amplitude of accommodation, accommodative lag, and accommodative sensitivity of patients wearing glasses for 6 and 12mo were significantly elevated (P0.05, and the asthenopia grating was not significantly decreased (P>0.05. In addition, after wearing glasses for 6 to 12mo, the asthenopia grating of patients in the test group decreased significantly compared with the control group (P0.05. CONCLUSION: A 1-year follow-up reveal that compare with ordinary glasses, short-wavelength filtering lenses (blue/violet-light filters increase the low- and medium-frequency contrast sensitivity under bright conditions and improved accommodation. They effectively relieved asthenopia without severe adverse reactions, suggesting potential for clinical application. However, no significant advantages in terms of refractive power or axial length progression were found compared

  18. Retropupillary iris claw intraocular lens implantation in aphakia for dislocated intraocular lens.

    Science.gov (United States)

    Faria, Mun Yueh; Ferreira, Nuno Pinto; Pinto, Joana Medeiros; Sousa, David Cordeiro; Leal, Ines; Neto, Eliana; Marques-Neves, Carlos

    2016-01-01

    Nowadays, dislocated intraocular lenses (IOLs) and inadequate capsular support are becoming a challenge for every ophthalmic surgeon. Explantation of dislocated IOL and iris claw IOL (ICIOL) are the techniques that have been used in our ophthalmic department. The aim of this study is to report our technique for retropupillar ICIOL. This study is a retrospective case series. A total of 105 eyes with dislocated IOL from the patients at the Department of Ophthalmology in Santa Maria Hospital, a tertiary reference hospital in Lisbon, Portugal, from January 2012 until January 2016, had been analyzed. Of these 105 eyes, 66 eyes had dislocated one-piece IOL and 39 eyes had dislocated three-piece IOL. The latter underwent iris suture of the same IOL and were excluded from this study. The remaining 66 eyes with dislocated one-piece IOL underwent pars plana vitrectomy, that is, explantation of dislocated IOL through corneal incision and an implantation of retropupillary ICIOL. Operative data and postoperative outcomes included best corrected visual acuity, IOL position, intraocular pressure, pigment dispersion, clinical signs of endothelial cell loss, and anterior chamber depth. The mean follow-up was 23 months (range: 6-48 months). The mean preoperative best corrected visual acuity was 1.260±0.771 logMAR, and postoperative best corrected visual acuity was 0.352±0.400 logMAR units. Mean vision gain was 0.909 logMar units. The patients had the following complications: 1) retinal detachment was found in one patient, 2) corneal edema was found in three patients, 3) high intraocular pressure was observed in twelve patients, 4) subluxation of the IOL was observed in one patient, and 5) macular edema was found in three eyes. The results demonstrate that retropupillary ICIOL is an easy and effective method for the correction of aphakia in patients not receiving capsule support. The safety of this procedure must be interpreted in the context of a surgery usually indicated in

  19. Retropupillary iris claw intraocular lens implantation in aphakia for dislocated intraocular lens

    Directory of Open Access Journals (Sweden)

    Faria MY

    2016-08-01

    Full Text Available Mun Yueh Faria,1–3 Nuno Pinto Ferreira,1–3 Joana Medeiros Pinto,1–3 David Cordeiro Sousa,1–3 Ines Leal,1–3 Eliana Neto,1–3 Carlos Marques-Neves1–3 1Centro de Estudos da Visão, Universidade de Lisboa, 2Department of Ophthalmology, Hospital de Santa Maria, 3Faculty of Medicine, University of Lisbon, Lisbon, Portugal Background: Nowadays, dislocated intraocular lenses (IOLs and inadequate capsular support are becoming a challenge for every ophthalmic surgeon. Explantation of dislocated IOL and iris claw IOL (ICIOL are the techniques that have been used in our ophthalmic department. The aim of this study is to report our technique for retropupillar ICIOL.Methods: This study is a retrospective case series. A total of 105 eyes with dislocated IOL from the patients at the Department of Ophthalmology in Santa Maria Hospital, a tertiary reference hospital in Lisbon, Portugal, from January 2012 until January 2016, had been analyzed. Of these 105 eyes, 66 eyes had dislocated one-piece IOL and 39 eyes had dislocated three-piece IOL. The latter underwent iris suture of the same IOL and were excluded from this study. The remaining 66 eyes with dislocated one-piece IOL underwent pars plana vitrectomy, that is, explantation of dislocated IOL through corneal incision and an implantation of retropupillary ICIOL. Operative data and postoperative outcomes included best corrected visual acuity, IOL position, intraocular pressure, pigment dispersion, clinical signs of endothelial cell loss, and anterior chamber depth.Results: The mean follow-up was 23 months (range: 6–48 months. The mean preoperative best corrected visual acuity was 1.260±0.771 logMAR, and postoperative best corrected visual acuity was 0.352±0.400 logMAR units. Mean vision gain was 0.909 logMar units. The patients had the following complications: 1 retinal detachment was found in one patient, 2 corneal edema was found in three patients, 3 high intraocular pressure was observed in

  20. An Instrument for Inspecting Aspheric Optical Surfaces and Components, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a Phase II SBIR proposal to develop an extremely versatile optical inspection tool for aspheric optical components and optics that are not easily inspected...

  1. An Instrument for Inspecting Aspheric Optical Surfaces and Components, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a Phase I proposal to develop an extremely versatile optical inspection tool for determining the optical figure of aspheric optical components, such as test...

  2. Very large computer generated holograms for precision metrology of aspheric optical surfaces, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Both ground and space telescopes employ aspheric mirrors. A particular example is the X-ray telescope where primary and secondary mirrors have nearly cylindrical...

  3. Research on the method of improving the accuracy of CMM (coordinate measuring machine) testing aspheric surface

    Science.gov (United States)

    Cong, Wang; Xu, Lingdi; Li, Ang

    2017-10-01

    Large aspheric surface which have the deviation with spherical surface are being used widely in various of optical systems. Compared with spherical surface, Large aspheric surfaces have lots of advantages, such as improving image quality, correcting aberration, expanding field of view, increasing the effective distance and make the optical system compact, lightweight. Especially, with the rapid development of space optics, space sensor resolution is required higher and viewing angle is requred larger. Aspheric surface will become one of the essential components in the optical system. After finishing Aspheric coarse Grinding surface profile error is about Tens of microns[1].In order to achieve the final requirement of surface accuracy,the aspheric surface must be quickly modified, high precision testing is the basement of rapid convergence of the surface error . There many methods on aspheric surface detection[2], Geometric ray detection, hartmann detection, ronchi text, knifeedge method, direct profile test, interferometry, while all of them have their disadvantage[6]. In recent years the measure of the aspheric surface become one of the import factors which are restricting the aspheric surface processing development. A two meter caliber industrial CMM coordinate measuring machine is avaiable, but it has many drawbacks such as large detection error and low repeatability precision in the measurement of aspheric surface coarse grinding , which seriously affects the convergence efficiency during the aspherical mirror processing. To solve those problems, this paper presents an effective error control, calibration and removal method by calibration mirror position of the real-time monitoring and other effective means of error control, calibration and removal by probe correction and the measurement mode selection method to measure the point distribution program development. This method verified by real engineer examples, this method increases the original industrial

  4. Retropupillary Fixation of Iris-Claw Intraocular Lens for Aphakic Eyes in Children.

    Directory of Open Access Journals (Sweden)

    Martina Brandner

    Full Text Available To report outcome, complications and safety of retropupillary fixated iris-claw intraocular lenses in a pediatric population.Retrospective study.Ten consecutive pediatric patients (15 eyes underwent placement of retropupillary fixated iris-claw intraocular lenses between October 2007 and July 2013 at the Department of Ophthalmology, Medical University Graz and General Hospital Klagenfurt, Austria. Postoperative visual acuity and complications were analyzed.Median final best-corrected visual acuity improved by 0.12 logMAR from preoperative baseline. Mean postoperative spherical equivalent was -0.05 ± 1.76 D. No serious complications were observed intra- or postoperatively during the entire follow-up period of up to 40 months. One patient experienced a haptic disenclavation with IOL subluxation immediately after a car accident.Our study demonstrates that iris-claw intraocular lens implantation behind the iris is safe in children with lack of capsular support and yields excellent visual outcome with low complication rate.

  5. Retropupillary Fixation of Iris-Claw Intraocular Lens for Aphakic Eyes in Children

    Science.gov (United States)

    Brandner, Martina; Thaler-Saliba, Sarah; Plainer, Sophie; Vidic, Bertram; El-Shabrawi, Yosuf; Ardjomand, Navid

    2015-01-01

    Purpose To report outcome, complications and safety of retropupillary fixated iris-claw intraocular lenses in a pediatric population. Design Retrospective study. Patients and Methods Ten consecutive pediatric patients (15 eyes) underwent placement of retropupillary fixated iris-claw intraocular lenses between October 2007 and July 2013 at the Department of Ophthalmology, Medical University Graz and General Hospital Klagenfurt, Austria. Postoperative visual acuity and complications were analyzed. Results Median final best-corrected visual acuity improved by 0.12 logMAR from preoperative baseline. Mean postoperative spherical equivalent was -0.05 ± 1.76 D. No serious complications were observed intra- or postoperatively during the entire follow-up period of up to 40 months. One patient experienced a haptic disenclavation with IOL subluxation immediately after a car accident. Conclusion Our study demonstrates that iris-claw intraocular lens implantation behind the iris is safe in children with lack of capsular support and yields excellent visual outcome with low complication rate. PMID:26110864

  6. Fresnel's Lighthouse Lenses

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2007-01-01

    One of the rewards of walking up the scores of steps winding around the inside of the shaft of a lighthouse is turning inward and examining the glass optical system. This arrangement of prisms, lenses, and reflectors is used to project the light from a relatively small source in a beam that can be seen far at sea.

  7. A framework of cloud supported collaborative design in glass lens moulds based on aspheric measurement

    Science.gov (United States)

    Zhu, Yongjian; Wang, Yu; Na, Jingxin; Zhi, Yanan; Fan, Yufeng

    2013-09-01

    Aspheric mould design includes the top-down design and reversal design. In this paper, a new framework of reversal design is proposed combining with cloud supported collaborative design (CSCD) based on aspheric measurement. The framework is a kind of collaborative platform, which is composed of eight modules, including the computerized aspheric precision measurement module (CAPM), computer-aided optical design of aspheric lens system (CAOD), computer-aided design of lens mould (CADLM), FEM(finite element method) simulation of lens molding module (FEMLM), computer-aided manufacture of lens and moulds (CAMLM), measurement data analysis module (MDAM), optical product lifecycle management module (OPLM) and cloud computing network module (CCNM). In this framework, the remote clients send an improved requirement or fabrication demand about optical lens system through CCNM, which transfers this signal to OPLM. In OPLM, one main server is in charge of the task distribution and collaborative work of other six modules. The first measurement data of aspheric lens are produced by clients or our proposed platform CAPM, then are sent to CAOD for optimization and the electronic drawings of lens moulds are generated in CADLM module. According the design drawings, the FEMLM could give the lens-molding simulation parameters through FEM software. The simulation data are used for the second design of moulds in CADLM module. In this case, the moulds could be fabricated in CAMLM by ultra-precision machine, and the aspheric lens could be also produced by lens-molding machine in CAMLM. At last, the final shape of aspheric lens could be measured in CAPM and the data analysis could be conducted in MDAM module. Through the proposed framework, all the work described above could be performed coordinately. And the optimum design data of lens mould could be realized and saved, then shared by all the work team.

  8. Study on combined polishing process of aspherical aluminum mirrors

    Science.gov (United States)

    Deng, Jinqiu; Peng, Xiaoqiang; Hu, Hao; Ge, Kunpeng

    2017-10-01

    The aluminum mirrors are widely used as important optical components in some vital fields such as astronomical instruments or military installations due to the unique advantages of aluminum alloy. In order to simplify the structure of optical system and improve the performance at the same time, it's a tendency that the optics will be designed to aspherical or other freeform shapes. However, the traditional techniques are falling to have adequate abilities to deal with the increasing demands of aluminum optics. For example, the tool marks leaved on the surface from single point diamond turning (SPDT) has obvious adverse effects to optical system. The deterministic and sub-aperture polishing process has showed the potential to fabricate complex shapes over the few years. But it's still recognized as a problem to polish bare aluminum directly because of its soft surface and active chemical characteristics. Therefore, a combination of magnetorheological finishing (MRF) and small tool polishing (STP) is applied to obtain high performance aluminum optics in this paper. A paraboloid aluminum mirror was polished with this proposed method, and the results showed that the surface texture of the sample is restrained from rms 0.409λ (λ=632.8nm) to rms 0.025λ, and the surface roughness is improved from average Ra 6 7nm to Ra 3 4nm.

  9. MRI and intraocular tamponade media

    International Nuclear Information System (INIS)

    Manfre, I.; Fabbri, G.; Avitabile, T.; Biondi, P.; Reibaldi, A.; Pero, G.

    1993-01-01

    Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, flurosilicone oil, or perfluoro-carbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment. (orig.)

  10. MRI and intraocular tamponade media

    Energy Technology Data Exchange (ETDEWEB)

    Manfre, I. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy)); Fabbri, G. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy)); Avitabile, T. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Biondi, P. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Reibaldi, A. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Pero, G. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy))

    1993-05-01

    Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, flurosilicone oil, or perfluoro-carbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment. (orig.)

  11. Clinical outcomes of a new diffractive multifocal intraocular lens

    Directory of Open Access Journals (Sweden)

    Baha Toygar

    2017-12-01

    Full Text Available AIM: To evaluate clinical outcomes after implantation of a new diffractive aspheric multifocal intraocular lens (IOL with +3.00 addition power. METHODS: This is a retrospective, consecutive case series of cataract patients who underwent bilateral implantation of the Optiflex MO/HF D012 (Moss Vision Inc. Ltd, London, UK multifocal IOL. Patients followed for 6mo were included in the study. Data on distance, intermediate and near visual acuity, refractive error [manifest spherical equivalent (MSE], contrast sensitivity, adverse events, subjective symptoms, spectacle independence and patient satisfaction [visual function questionnaire (VFQ-25 questionnaire] were retrieved from electronic medical records and analyzed. RESULTS: Forty eyes of 20 patients with a mean age of 66.7±8.5y (range: 53-82 were included in the study. Mean uncorrected distance, near and intermediate visual acuity remained stable through postoperative visits and was 0.19±0.19 logMAR, Jaeger 4 and Jaeger 3 respectively at the 6mo visit. At the end of postoperative 6mo, MSE was -0.14±0.42 diopters (D and 98% of the eyes were within 1.00 D of target refraction. Postoperative low contrast (10% visual acuity remained stable (P=0.54 through follow up visits with a mean of 0.35±0.17 logMAR at the 6mo visit. There were no reported adverse events. None of the patients reported subjective symptoms of halo or glare. Spectacle independence rate was 90%. Mean VFQ-25 questionnaire score was 93.5±6.12. CONCLUSION: The Optiflex MO/HF-DO12 IOL was safely implanted and successfully restored distance, intermediate and near visual acuity without impairing contrast sensitivity. High levels of spectacle independence were achieved at all distances including intermediate distance.

  12. Observations of gravitational lenses

    International Nuclear Information System (INIS)

    Fort, B.

    1990-01-01

    During the last tow years a burst of results has come from radio and optical surveys of ''galaxy lenses'' (where the main deflector is a galaxy). These are reviewed. On the other hand, in September 1985 we pointed out a very strange blue ring-like structure on a Charge-Coupled Device image of the cluster of galaxies Abell 370. This turned out to be Einstein arcs discovery. Following this discovery, new observational results have shown that many rich clusters of galaxies can produce numerous arclets: tangentially distorted images of an extremely faint galaxy population probably located at redshift larger than 1. This new class of gravitational lenses proves to be an important observational topic and this will be discussed in the second part of the paper. (author)

  13. Measurement of aspheric surfaces using an improved annular subaperture stitching interferometry (IASSI)

    International Nuclear Information System (INIS)

    Wen, Yongfu; Cheng, Haobo

    2014-01-01

    An improved annular subaperture stitching interferometry (IASSI) is proposed for testing aspheric surfaces in the stage of precision polishing. It includes a reasonable stitching model and an automatic positioning operation. In the testing process, a series of optical path difference (OPD) data of annular subapertures is obtained as the interferometer is gradually shifted relative to the tested aspheric surface. Then these OPD data can be analyzed by the automatic positioning operation to get the key stitching parameters, and can be stitched together based on a reasonable mathematical model. To verify its validity, we study the applicability of the method to subaperture stitching tests of two conic aspheric surfaces. The stitching results agreed with the full-aperture test results. (paper)

  14. Primary anterior chamber intraocular lens for the treatment of severe crystalline lens subluxation.

    Science.gov (United States)

    Hoffman, Richard S; Fine, I Howard; Packer, Mark

    2009-10-01

    Subluxated cataractous and clear lenses are commonly treated by limbal or pars plana lensectomy followed by primary or secondary intraocular lens (IOL) implantation. Adjunctive capsular prosthetic devices have facilitated lens removal and IOL centration in these challenging cases but have also added complexity and potential complications to the procedure. Although crystalline lens extraction may be required to clear the visual axis in mild to moderate lens subluxations, we propose insertion of a primary anterior chamber IOL without lens extraction in severe subluxations when the eye is optically aphakic or can be made functionally aphakic following neodymium:YAG laser zonulysis. Two cases demonstrating this approach are presented.

  15. Intraocular Ossification in the GSP/pe Chicken With Imperfect Albinism.

    Science.gov (United States)

    Shibuya, K; Kinoshita, K; Mizutani, M; Oshima, A; Yamashita, R; Matsuda, Y

    2015-07-01

    The eyes of 2 male and 2 female GSP/pe chickens, the imperfect albino strain, were investigated at 52 weeks of age. Aged chickens of the GSP/pe colony became blind with bilateral ocular enlargement and opaque lenses. Affected eyes (bilateral in 2 males and unilateral in 2 females) were hard and difficult to section; histologic specimens were processed after decalcification. A large portion of the posterior chamber was occupied by cancellous bone containing fibrous and cartilaginous foci. Osseous tissues developed adjacent to the choroid, and no retinal pigment epithelium (RPE) was detected between osseous tissues and the choroid. Small segments of degenerate neuronal retina were scattered in the osseous tissue. The irises and ciliary bodies were deformed by osseous tissue, and the lenses had severe cataracts. These observations suggest that the intraocular osseous tissue may be derived from RPE in the hereditary incomplete-albino strain of chickens. © The Author(s) 2014.

  16. 21 CFR 886.3600 - Intraocular lens.

    Science.gov (United States)

    2010-04-01

    ... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification. An intraocular lens is a device made of materials such as glass or plastic intended to be implanted to replace the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a...

  17. 21 CFR 886.4275 - Intraocular fluid.

    Science.gov (United States)

    2010-04-01

    ... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4275 Intraocular fluid. (a) Identification. An intraocular fluid is a device consisting of a nongaseous fluid intended to be introduced into the eye to aid... section 515 of the act is required before this device may be commercially distributed. See § 886.3. ...

  18. 21 CFR 886.4270 - Intraocular gas.

    Science.gov (United States)

    2010-04-01

    ... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4270 Intraocular gas. (a) Identification. An intraocular gas is a device consisting of a gaseous fluid intended to be introduced into the eye to place pressure... required. As of May 28, 1976, an approval under section 515 of the act is required before this device may...

  19. Photodynamic therapy of intraocular cancers

    International Nuclear Information System (INIS)

    Gravier, N.; Duvournau, Y.; Querec, M.A.; Pechereau, A.; Patrice, T.

    1992-01-01

    The most common intraocular tumors are choroidal malignant melanomas (70%) and retinoblastomas (13%). Each time that visual acuity is preserved, various conservative treatments are considered relative to the potential risk of metastatic disease during enucleation. In addition to standard techniques, photodynamic therapy is a potentially attractive new approach limited in its effects to the area of the treated tumor. The purpose of this preclinical study is to determine a reference dose-effect for single laser doses and to study effects of fractionation of the laser dose. (author). 9 refs., 1 tab

  20. Additive manufacturing of tunable lenses

    Science.gov (United States)

    Schlichting, Katja; Novak, Tobias; Heinrich, Andreas

    2017-02-01

    Individual additive manufacturing of optical systems based on 3D Printing offers varied possibilities in design and usage. In addition to the additive manufacturing procedure, the usage of tunable lenses allows further advantages for intelligent optical systems. Our goal is to bring the advantages of additive manufacturing together with the huge potential of tunable lenses. We produced tunable lenses as a bundle without any further processing steps, like polishing. The lenses were designed and directly printed with a 3D Printer as a package. The design contains the membrane as an optical part as well as the mechanical parts of the lens, like the attachments for the sleeves which contain the oil. The dynamic optical lenses were filled with an oil. The focal length of the lenses changes due to a change of the radius of curvature. This change is caused by changing the pressure in the inside of the lens. In addition to that, we designed lenses with special structures to obtain different areas with an individual optical power. We want to discuss the huge potential of this technology for several applications. Further, an appropriate controlling system is needed. Wéll show the possibilities to control and regulate the optical power of the lenses. The lenses could be used for illumination tasks, and in the future, for individual measurement tasks. The main advantage is the individuality and the possibility to create an individual design which completely fulfills the requirements for any specific application.

  1. Accommodative intraocular lens versus standard monofocal intraocular lens implantation in cataract surgery.

    Science.gov (United States)

    Ong, Hon Shing; Evans, Jennifer R; Allan, Bruce D S

    2014-05-01

    Following cataract surgery and intraocular lens (IOL) implantation, loss of accommodation or postoperative presbyopia occurs and remains a challenge. Standard monofocal IOLs correct only distance vision; patients require spectacles for near vision. Accommodative IOLs have been designed to overcome loss of accommodation after cataract surgery. To define (a) the extent to which accommodative IOLs improve unaided near visual function, in comparison with monofocal IOLs; (b) the extent of compromise to unaided distance visual acuity; c) whether a higher rate of additional complications is associated the use of accommodative IOLs. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 9), Ovid MEDLINE, Ovid MEDLINE in-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily Update, Ovid OLDMEDLINE (January 1946 to October 2013), EMBASE (January 1980 to October 2013), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to October 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 October 2013. We include randomised controlled trials (RCTs) which compared implantation of accommodative IOLs to implantation of monofocal IOLs in cataract surgery. Two authors independently screened search results, assessed risk of bias and extracted data. All included trials used the 1CU accommodative IOL (HumanOptics, Erlangen, Germany) for their intervention group. One trial had an additional arm with the AT-45 Crystalens accommodative IOL (Eyeonics Vision). We performed a separate analysis comparing 1CU and AT-45 IOL. We included four RCTs, including 229 participants (256 eyes

  2. RHIC electron lenses upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Altinbas, Z. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Binello, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Costanzo, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Drees, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Gassner, D. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, J. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Harvey, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mi, C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Miller, T. A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Pikin, A. I. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Samms, T. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Shrey, T. C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Tan, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Than, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; White, S. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015, two electron lenses were used to partially compensate for the head-on beam-beam effect for the first time. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

  3. Analysis of causes of intraocular lens explantations in the material of Department of Ophthalmology, Medical University of Lodz.

    Science.gov (United States)

    Wilczyński, Michał; Wilczyńska, Olena; Omulecki, Wojciech

    2009-01-01

    Implantation of intraocular lenses (IOLS) has become a standard practice in cataract surgery, however, similar to any other type of surgery, using IOLs is not complication-free and sometimes explantation of intraocular lenses may be necessary. This study was to gather data and analyze causes of intraocular lens explantations, performed in the Department of Ophthalmology, Medical University of Łódź. The data were gathered from medical documentation of all patients who underwent intraocular lens removal from January 2003 to July 2006. The examined group consisted of 16 patients (16 eyes): 9 women (fraction 0.56), and 7 men (fraction 0.44), at the age from 21 to 82 years (mean age 62.4 years, SD +/- 15.5). In all patients IOL explantation was performed under local, peribulbar anaesthesia. Two groups of patients were distinguished: patients who had an anterior chamber lens explanted (3 patients, fraction 0.19) and patients who underwent posterior chamber lens explantation (13 patients, fraction 0.81). Causes of AC IOL explantations were: vaulting of the IOL (1 eye, fraction 0.06), luxation of the IOL to the vitreous cavity (1 eye, fraction 0.06), and painful eyeball after anterior chamber lens implantation (1 eye, fraction 0.06). Causes of PC IOL explantations were: subluxation of the IOL (6 eyes, fraction 0.38), luxation of the lens to the vitreous cavity (3 eyes, fraction 0.19), luxation of the lens to the anterior chamber (1 eye, fraction 0.06), endophthalmitis (2 eyes, fraction 0.13) and incorrect lens power (1 eye, fraction 0.06). In the majority of eyes (n = 13, fraction 0.81) the removed implant was replaced by another intraocular lens, but 3 eyes (fraction 0.19) were left aphakic. We did not observe serious intra- or early postoperative complications which might influence the final result of the operation.

  4. We are not the 99 percent: quantifying asphericity in the distribution of Local Group satellites

    Science.gov (United States)

    Forero-Romero, Jaime E.; Arias, Verónica

    2018-05-01

    We use simulations to build an analytic probability distribution for the asphericity in the satellite distribution around Local Group (LG) type galaxies in the Lambda Cold Dark Matter (LCDM) paradigm. We use this distribution to estimate the atypicality of the satellite distributions in the LG even when the underlying simulations do not have enough systems fully resembling the LG in terms of its typical masses, separation and kinematics. We demonstrate the method using three different simulations (Illustris-1, Illustris-1-Dark and ELVIS) and a number of satellites ranging from 11 to 15. Detailed results differ greatly among the simulations suggesting a strong influence of the typical DM halo mass, the number of satellites and the simulated baryonic effects. However, there are three common trends. First, at most 2% of the pairs are expected to have satellite distributions with the same asphericity as the LG; second, at most 80% of the pairs have a halo with a satellite distribution as aspherical as in M31; and third, at most 4% of the pairs have a halo with satellite distribution as planar as in the MW. These quantitative results place the LG at the level of a 3σ outlier in the LCDM paradigm. We suggest that understanding the reasons for this atypicality requires quantifying the asphericity probability distribution as a function of halo mass and large scale environment. The approach presented here can facilitate that kind of study and other comparisons between different numerical setups and choices to study satellites around LG pairs in simulations.

  5. Application for vibration monitoring of aspheric surface machining based on wireless sensor networks

    Science.gov (United States)

    Han, Chun Guang; Guo, Yin Biao; Jiang, Chen

    2010-05-01

    Any kinds of tiny vibration of machine tool parts will have a great influence on surface quality of the workpiece at ultra-precise machining process of aspheric surface. At present the major way for decreasing influence of vibration is machining compensation technology. Therefore it is important for machining compensation control to acquire and transmit these vibration signals effectively. This paper presents a vibration monitoring system of aspheric surface machining machine tool based on wireless sensor networks (WSN). Some key issues of wireless sensor networks for vibration monitoring system of aspheric surface machining are discussed. The reliability of data transmission, network communication protocol and synchronization mechanism of wireless sensor networks are studied for the vibration monitoring system. The proposed system achieves multi-sensors vibration monitoring involving the grinding wheel, the workpiece and the workbench spindle. The wireless transmission of vibration signals is achieved by the combination with vibration sensor nodes and wireless network. In this paper, these vibration sensor nodes are developed. An experimental platform is structured which employs wireless sensor networks to the vibration monitoring system in order to test acquisition and wireless transmission of vibration signal. The test results show that the proposed system can achieve vibration data transmission effectively and reliability and meet the monitoring requirements of aspheric surface machining machine tool.

  6. Magnetic electron lenses

    CERN Document Server

    1982-01-01

    No single volume has been entirely devoted to the properties of magnetic lenses, so far as I am aware, although of course all the numerous textbooks on electron optics devote space to them. The absence of such a volume, bringing together in­ formation about the theory and practical design of these lenses, is surprising, for their introduction some fifty years ago has created an entirely new family of commercial instruments, ranging from the now traditional transmission electron microscope, through the reflection and transmission scanning microscopes, to co­ lumns for micromachining and microlithography, not to mention the host of experi­ mental devices not available commercially. It therefore seemed useful to prepare an account of the various aspects of mag­ netic lens studies. These divide naturally into the five chapters of this book: the theoretical background, in which the optical behaviour is described and formu­ lae given for the various aberration coefficients; numerical methods for calculat­ ing...

  7. Gravitational lenses and cosmological evolution

    International Nuclear Information System (INIS)

    Peacock, J.A.

    1982-01-01

    The effect of gravitational lensing on the apparent cosmological evolution of extragalactic radio sources is investigated. Models for a lens population consisting of galaxies and clusters of galaxies are constructed and used to calculate the distribution of amplification factors caused by lensing. Although many objects at high redshifts are predicted to have flux densities altered by 10 to 20 per cent relative to a homogeneous universe, flux conservation implies that de-amplification is as common as amplification. The effects on cosmological evolution as inferred from source counts and redshift data are thus relatively small; the slope of the counts is not large enough for intrinsically rare lensing events of high amplitude to corrupt observed samples. Lensing effects may be of greater importance for optically selected quasars, where lenses of mass as low as approximately 10 -4 solar mass can cause large amplifications. (author)

  8. Design of a Test Bench for Intraocular Lens Optical Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Alba-Bueno, Francisco; Vega, Fidel; Millan, Maria S, E-mail: francisco.alba-bueno@upc.edu, E-mail: fvega@oo.upc.edu, E-mail: millan@oo.upc.edu [Departamento de Optica y Optometria, Universidad Politecnica de Cataluna, C/ Violinista Vellsola 37, 08222 Terrassa (Spain)

    2011-01-01

    The crystalline lens is the responsible for focusing at different distances (accommodation) in the human eye. This organ grows throughout life increasing in size and rigidity. Moreover, due this growth it loses transparency through life, and becomes gradually opacified causing what is known as cataracts. Cataract is the most common cause of visual loss in the world. At present, this visual loss is recoverable by surgery in which the opacified lens is destroyed (phacoemulsification) and replaced by the implantation of an intraocular lens (IOL). If the IOL implanted is mono-focal the patient loses its natural capacity of accommodation, and as a consequence they would depend on an external optic correction to focus at different distances. In order to avoid this dependency, multifocal IOLs designs have been developed. The multi-focality can be achieved by using either, a refractive surface with different radii of curvature (refractive IOLs) or incorporating a diffractive surface (diffractive IOLs). To analyze the optical quality of IOLs it is necessary to test them in an optical bench that agrees with the ISO119679-2 1999 standard (Ophthalmic implants. Intraocular lenses. Part 2. Optical Properties and Test Methods). In addition to analyze the IOLs according to the ISO standard, we have designed an optical bench that allows us to simulate the conditions of a real human eye. To do that, we will use artificial corneas with different amounts of optical aberrations and several illumination sources with different spectral distributions. Moreover, the design of the test bench includes the possibility of testing the IOLs under off-axis conditions as well as in the presence of decentration and/or tilt. Finally, the optical imaging quality of the IOLs is assessed by using common metrics like the Modulation Transfer Function (MTF), the Point Spread Function (PSF) and/or the Strehl ratio (SR), or via registration of the IOL's wavefront with a Hartmann-Shack sensor and its

  9. Lessons learned: wrong intraocular lens.

    Science.gov (United States)

    Schein, Oliver D; Banta, James T; Chen, Teresa C; Pritzker, Scott; Schachat, Andrew P

    2012-10-01

    To report cases involving the placement of the wrong intraocular lens (IOL) at the time of cataract surgery where human error occurred. Retrospective small case series, convenience sample. Seven surgical cases. Institutional review of errors committed and subsequent improvements to clinical protocols. Lessons learned and changes in procedures adapted. The pathways to a wrong IOL are many but largely reflect some combination of poor surgical team communication, transcription error, lack of preoperative clarity in surgical planning or failure to match the patient, and IOL calculation sheet with 2 unique identifiers. Safety in surgery involving IOLs is enhanced both by strict procedures, such as an IOL-specific "time-out," and the fostering of a surgical team culture in which all members are encouraged to voice questions and concerns. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  10. Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal; Koester, Benjamin P.; Sharon, Keren; Bayliss, Matthew

    2009-01-29

    We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significantly improves constraints on the mass density profile, compared to those obtained from weak lensing alone. While the mass profiles are well fitted by the universal form predicted in N-body simulations of the {Lambda}-dominated cold dark matter model, all four clusters appear to be slightly more centrally concentrated (the concentration parameters c{sub vir} {approx} 8) than theoretical predictions, even after accounting for the bias toward higher concentrations inherent in lensing selected samples. Our results are consistent with previous studies which similarly detected a concentration excess, and increases the total number of clusters studied with the combined strong and weak lensing technique to ten. Combining our sample with previous work, we find that clusters with larger Einstein radii are more anomalously concentrated. We also present a detailed model of the lensing cluster Abell 1703 with constraints from multiple image families, and find the dark matter inner density profile to be cuspy with the slope consistent with -1, in agreement with expectations.

  11. Refractive outcomes of an advanced aspherically optimized profile for myopia corrections by LASIK: a retrospective comparison with the standard aspherically optimized profile

    Directory of Open Access Journals (Sweden)

    Meyer B

    2015-02-01

    Full Text Available Bertram Meyer,1 Georg Sluyterman van Langeweyde,2 Matthias Wottke2 1Augencentrum Köln, Cologne, Germany; 2Carl Zeiss Meditec AG, Jena, Germany Purpose: A retrospective comparison of refractive outcomes of a new, aspherically optimized profile with an enhanced energy correction feature (Triple-A and the conventionally used aspherically optimized profile (ASA, or aberration smart ablation for correction of low-to-high myopia.Setting: Augen-OP-Centrum, Cologne, GermanyDesign: Retrospective nonrandomized comparative studyMethods: A central database at the Augen-OP-Centrum was used to gather retrospective data for low-to-high myopia (up to -10 D. One hundred and seven eyes (56 patients were treated with the ASA profile, and 79 eyes (46 patients were treated with the Triple-A profile. Postoperative outcomes were evaluated at 1 month, 3 months, 6 months, and 1 year follow-up time points.Results: The Triple-A profile showed better predictability indicated by a significantly lower standard deviation of residuals (0.32–0.34 vs 0.36–0.44, Triple-A vs ASA in the 6-month to 1-year period. The Triple-A group had better stability across all time intervals and achieved better postoperative astigmatism improvements with significantly lower scatter. This group achieved better safety at 1 year, with 100% of eyes showing no change or gain in Snellen lines, compared with 97% in the ASA group. A better safety index was observed for the Triple-A group at later time points. The Triple-A group had a better efficacy index and a higher percentage of eyes with an uncorrected Snellen visual acuity of 20/20 or greater at all investigated follow-up time points.Conclusion: The new aspherically optimized Triple-A profile can safely and effectively correct low-to-high myopia. It has demonstrated superiority over the ASA profile in most refractive outcomes. Keywords: Triple-A, wavefront measurements, corneal aberrations, corneal asphericity, ablation profile

  12. CMB lensing and giant rings

    Energy Technology Data Exchange (ETDEWEB)

    Rathaus, Ben; Itzhaki, Nissan, E-mail: nitzhaki@post.tau.ac.il, E-mail: ben.rathaus@gmail.com [Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv University, Ramat-Aviv, 69978 (Israel)

    2012-05-01

    We study the CMB lensing signature of a pre-inationary particle (PIP), assuming it is responsible for the giant rings anomaly that was found recently in the WMAP data. Simulating Planck-like data we find that generically the CMB lensing signal to noise ratio associated with such a PIP is quite small and it would be difficult to cross correlate the temperature giant rings with the CMB lensing signal. However, if the pre-inationary particle is also responsible for the bulk flow measured from the local large scale structure, which happens to point roughly at the same direction as the giant rings, then the CMB lensing signal to noise ratio is fairly significant.

  13. KINOFORM LENSES - TOWARD NANOMETER RESOLUTION.

    Energy Technology Data Exchange (ETDEWEB)

    STEIN, A.; EVANS-LUTTERODT, K.; TAYLOR, A.

    2004-10-23

    While hard x-rays have wavelengths in the nanometer and sub-nanometer range, the ability to focus them is limited by the quality of sources and optics, and not by the wavelength. A few options, including reflective (mirrors), diffractive (zone plates) and refractive (CRL's) are available, each with their own limitations. Here we present our work with kinoform lenses which are refractive lenses with all material causing redundant 2{pi} phase shifts removed to reduce the absorption problems inherently limiting the resolution of refractive lenses. By stacking kinoform lenses together, the effective numerical aperture, and thus the focusing resolution, can be increased. The present status of kinoform lens fabrication and testing at Brookhaven is presented as well as future plans toward achieving nanometer resolution.

  14. Ultraviolet-B phototoxicity and hypothetical photomelanomagenesis: intraocular and crystalline lens photoprotection.

    Science.gov (United States)

    Mainster, Martin A; Turner, Patricia L

    2010-04-01

    Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Optical radiation measurement, analysis, and perspective. Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Crystalline lens UV-B retinal protection is deficient in children and young adults, increasing their potential susceptibility to acute retinal phototoxicity and hypothetical photomelanomagenesis. UV-B radiation has sufficient energy/photon to induce primary melanomagenic DNA lesions, unlike blue light or UV-A radiation. UV-blocking and blue-blocking IOLs have negligible UV-B transmittance. UV-transmitting IOL transmittance of UV-B radiation is equivalent to that of a 15-year-old crystalline lens. If optical radiation exposure is responsible for welders' increased risk of uveal melanoma, then UV-B radiation is the most probable causative agent and spectacle wear is a potential confounding factor in epidemiologic studies of ocular melanoma. Welders under 30 years of age are at greater risk for welding maculopathy than older welders. Children, adults under 30 years of age, and pseudophakic individuals with UV-transmitting IOLs should wear sunglasses in bright environments because of the UV-B window in their crystalline lenses or IOLs. Copyright 2010 Elsevier Inc. All rights reserved.

  15. Capsule-Fixated Intraocular Lens Implantation in Small Pupil Cases.

    Science.gov (United States)

    Schojai, Merita; Schultz, Tim; Burkhard Dick, H

    2017-08-01

    To describe a new technique for implantation of capsule-fixated intraocular lenses (IOLs) (FEMTIS; Oculentis, Berlin, Germany) in patients with small pupils. In 4 eyes with small pupils, an anterior capsule-fixated IOL was implanted into the capsular bag after femtosecond laser treatment. The two large and two small flaps of the IOL were elevated to the front of the iris and the anterior capsule. Finally, the iris was flipped over the flaps to ensure a fixation of the capsule inside of the capsulotomy. In all cases, the implantation of anterior capsule-fixated IOLs was possible. No complications occurred during surgery or within the first months after surgery. With the described technique, capsulefixated IOLs can be implanted in eyes with small pupil easily and safely. This type of IOL has great potential to improve the refractive outcome by better prediction of the postoperative IOL position and eliminating IOL rotation after cataract surgery. [J Refract Surg. 2017;33(8):568-570.]. Copyright 2017, SLACK Incorporated.

  16. Astrophysical Applications of Gravitational Lensing

    Science.gov (United States)

    Mediavilla, Evencio; Muñoz, Jose A.; Garzón, Francisco; Mahoney, Terence J.

    2016-10-01

    Contributors; Participants; Preface; Acknowledgements; 1. Lensing basics Sherry H. Suyu; 2. Exoplanet microlensing Andrew Gould; 3. Case studies of microlensing Veronica Motta and Emilio Falco; 4. Microlensing of quasars and AGN Joachim Wambsganss; 5. DM in clusters and large-scale structure Peter Schneider; 6. The future of strong lensing Chris Fassnacht; 7. Methods for strong lens modelling Charles Keeton; 8. Tutorial on inverse ray shooting Jorge Jimenez-Vicente.

  17. Biopsy techniques for intraocular tumors

    Directory of Open Access Journals (Sweden)

    Pukhraj Rishi

    2016-01-01

    Full Text Available Biopsy involves the surgical removal of a tissue specimen for histopathologic evaluation. Most intraocular tumors are reliably diagnosed based on the clinical evaluation or with noninvasive diagnostic techniques. However, accurately diagnosing a small percentage of tumors can be challenging. A tissue biopsy is thus needed to establish a definitive diagnosis and plan the requisite treatment. From fine-needle aspiration biopsy (FNAB to surgical excision, all tissue collection techniques have been studied in the literature. Each technique has its indications and limitations. FNAB has been reported to provide for 88-95% reliable and safe ophthalmic tumor diagnosis and has gained popularity for prognostic purposes and providing eye conserving treatment surgeries. The technique and instrumentation for biopsy vary depending upon the tissue involved (retina, choroid, subretinal space, vitreous, and aqueous, suspected diagnosis, size, location, associated retinal detachment, and clarity of the media. The cytopathologist confers a very important role in diagnosis and their assistance plays a key role in managing and planning the treatment for malignancies.

  18. MR imaging of intraocular hemorrhage

    International Nuclear Information System (INIS)

    Saint-Louis, L.A.; Weiss, R.; Ellsworth, R.; Chang, S.; Deck, M.D.F.

    1987-01-01

    The authors evaluated with MR imaging 11 globes (nine patients) with spontaneous or traumatic intraocular hemorrhage. Subretinal blood was present in eight. Intravitreal bleeding was associated in seven and three subchoroidal. The ages of the hemorrhages ranged from 1 day to 6 months. Six of the subretinal and two subchoroidal cases had clotted blood with different intensity on the short TE images but were markedly hypointense on long TR/long TE images. The intravitreal blood was hyperintense on all sequences except in one. All imaging was performed with .5 T, 256 matrix, and 4- and 7- mm section thickness. Because of the varied appearance of hemorrhages, the authors scanned and are scanning two rabbits with intravitreal blood in vivo. Parameters include: 3-mm sections, T1, PD, T2 scans in .3-T and 1.5-T imagers. Initial results for the first 2 days show no change in signal intensity (hyperintense on all sequences). The T1 images show a diminishing intensity up to 8 days, and T2 scans remained hyperintense. These results so far correlate with the patient findings. The authors present the clinical findings and experimental correlation

  19. Manufacturing aspheric mirrors made of zero thermal expansion cordierite ceramics using Magnetorheological Finishing (MRF)

    Science.gov (United States)

    Sugawara, Jun; Maloney, Chris

    2016-07-01

    NEXCERATM cordierite ceramics, which have ultra-low thermal expansion properties, are perfect candidate materials to be used for light-weight satellite mirrors that are used for geostationary earth observation and for mirrors used in ground-based astronomical metrology. To manufacture the high precision aspheric shapes required, the deterministic aspherization and figure correction capabilities of Magnetorheological Finishing (MRF) are tested. First, a material compatibility test is performed to determine the best method for achieving the lowest surface roughness of RMS 0.8nm on plano surfaces made of NEXCERATM ceramics. Secondly, we will use MRF to perform high precision figure correction and to induce a hyperbolic shape into a conventionally polished 100mm diameter sphere.

  20. Optimal design of tilt carrier frequency computer-generated holograms to measure aspherics.

    Science.gov (United States)

    Peng, Jiantao; Chen, Zhe; Zhang, Xingxiang; Fu, Tianjiao; Ren, Jianyue

    2015-08-20

    Computer-generated holograms (CGHs) provide an approach to high-precision metrology of aspherics. A CGH is designed under the trade-off among size, mapping distortion, and line spacing. This paper describes an optimal design method based on the parametric model for tilt carrier frequency CGHs placed outside the interferometer focus points. Under the condition of retaining an admissible size and a tolerable mapping distortion, the optimal design method has two advantages: (1) separating the parasitic diffraction orders to improve the contrast of the interferograms and (2) achieving the largest line spacing to minimize sensitivity to fabrication errors. This optimal design method is applicable to common concave aspherical surfaces and illustrated with CGH design examples.

  1. Conformal Interpolating Algorithm Based on Cubic NURBS in Aspheric Ultra-Precision Machining

    International Nuclear Information System (INIS)

    Li, C G; Zhang, Q R; Cao, C G; Zhao, S L

    2006-01-01

    Numeric control machining and on-line compensation for aspheric surface are key techniques in ultra-precision machining. In this paper, conformal cubic NURBS interpolating curve is applied to fit the character curve of aspheric surface. Its algorithm and process are also proposed and imitated by Matlab7.0 software. To evaluate the performance of the conformal cubic NURBS interpolation, we compare it with the linear interpolations. The result verifies this method can ensure smoothness of interpolating spline curve and preserve original shape characters. The surface quality interpolated by cubic NURBS is higher than by line. The algorithm is benefit to increasing the surface form precision of workpieces in ultra-precision machining

  2. Using neutral network to infer the hydrodynamic yield of aspherical sources

    International Nuclear Information System (INIS)

    Moran, B.; Glenn, L.A.

    1993-07-01

    We distinguish two kinds of difficulties with yield determination from aspherical sources. The first kind, the spoofing difficulty, occurs when a fraction of the energy of the explosion is channeled in such a way that it is not detected by the CORRTEX cable. In this case, neither neural networks nor any expert system can be expected to accurately estimate the yield without detailed information about device emplacement within the canister. Numerical simulations however, can provide an upper bound on the undetected fraction of the explosive energy. In the second instance, the interpretation difficulty, the data appear abnormal when analyzed using similar-explosion-scaling and the assumption of a spherical front. The inferred yield varies with time and the confidence in the yield estimate decreases. It is this kind of problem we address in this paper and for which neural networks can make a contribution. We used a back propagation neural network to infer the hydrodynamic yield of simulated aspherical sources. We trained the network using a subset of simulations from 3 different aspherical sources, with 3 different yields, and 3 satellite offset separations. The trained network was able to predict the yield within 15% in all cases and to identify the correct type of aspherical source in most cases. The predictive capability of the network increased with a larger training set. The neural network approach can easily incorporate information from new calculations or experiments and is therefore flexible and easy to maintain. We describe the potential capabilities and limitations in using such networks for yield estimations

  3. Using neural networks to infer the hydrodynamic yield of aspherical sources

    International Nuclear Information System (INIS)

    Moran, B.; Glenn, L.

    1993-01-01

    We distinguish two kinds of difficulties with yield determination from aspherical sources. The first kind, the spoofing difficulty, occurs when a fraction of the energy of the explosion is channeled in such a way that it is not detected by the CORRTEX cable. In this case, neither neural networks nor any expert system can be expected to accurately estimate the yield without detailed information about device emplacement within the canister. Numerical simulations however, can provide an upper bound on the undetected fraction of the explosive energy. In the second instance, the interpretation difficulty, the data appear abnormal when analyzed using similar-explosion-scaling and the assumption of a spherical front. The inferred yield varies with time and the confidence in the yield estimate decreases. It is this kind of problem we address in this paper and for which neural networks can make a contribution. We used a back propagation neural network to infer the hydrodynamic yield of simulated aspherical sources. We trained the network using a subset of simulations from 3 different aspherical sources, with 3 different yield, and 3 satellite offset separations. The trained network was able to predict the yield within 15% in all cases and to identify the correct type of aspherical source in most cases. The predictive capability of the network increased with a larger training set. The neural network approach can easily incorporate information from new calculations or experiments and is therefore flexible and easy to maintain. We describe the potential capabilities and limitations in using such networks for yield estimations

  4. Cosmology with weak lensing surveys

    International Nuclear Information System (INIS)

    Munshi, Dipak; Valageas, Patrick; Waerbeke, Ludovic van; Heavens, Alan

    2008-01-01

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening matter. The distortions are due to fluctuations in the gravitational potential, and are directly related to the distribution of matter and to the geometry and dynamics of the Universe. As a consequence, weak gravitational lensing offers unique possibilities for probing the Dark Matter and Dark Energy in the Universe. In this review, we summarise the theoretical and observational state of the subject, focussing on the statistical aspects of weak lensing, and consider the prospects for weak lensing surveys in the future. Weak gravitational lensing surveys are complementary to both galaxy surveys and cosmic microwave background (CMB) observations as they probe the unbiased non-linear matter power spectrum at modest redshifts. Most of the cosmological parameters are accurately estimated from CMB and large-scale galaxy surveys, so the focus of attention is shifting to understanding the nature of Dark Matter and Dark Energy. On the theoretical side, recent advances in the use of 3D information of the sources from photometric redshifts promise greater statistical power, and these are further enhanced by the use of statistics beyond two-point quantities such as the power spectrum. The use of 3D information also alleviates difficulties arising from physical effects such as the intrinsic alignment of galaxies, which can mimic weak lensing to some extent. On the observational side, in the next few years weak lensing surveys such as CFHTLS, VST-KIDS and Pan-STARRS, and the planned Dark Energy Survey, will provide the first weak lensing surveys covering very large sky areas and depth. In the long run even more ambitious programmes such as DUNE, the Supernova Anisotropy Probe (SNAP) and Large-aperture Synoptic Survey Telescope (LSST) are planned. Weak lensing of diffuse components such as the CMB and 21 cm emission can also

  5. Cosmology with weak lensing surveys

    Energy Technology Data Exchange (ETDEWEB)

    Munshi, Dipak [Institute of Astronomy, Madingley Road, Cambridge, CB3 OHA (United Kingdom); Astrophysics Group, Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE (United Kingdom)], E-mail: munshi@ast.cam.ac.uk; Valageas, Patrick [Service de Physique Theorique, CEA Saclay, 91191 Gif-sur-Yvette (France); Waerbeke, Ludovic van [University of British Columbia, Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Heavens, Alan [SUPA - Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)

    2008-06-15

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening matter. The distortions are due to fluctuations in the gravitational potential, and are directly related to the distribution of matter and to the geometry and dynamics of the Universe. As a consequence, weak gravitational lensing offers unique possibilities for probing the Dark Matter and Dark Energy in the Universe. In this review, we summarise the theoretical and observational state of the subject, focussing on the statistical aspects of weak lensing, and consider the prospects for weak lensing surveys in the future. Weak gravitational lensing surveys are complementary to both galaxy surveys and cosmic microwave background (CMB) observations as they probe the unbiased non-linear matter power spectrum at modest redshifts. Most of the cosmological parameters are accurately estimated from CMB and large-scale galaxy surveys, so the focus of attention is shifting to understanding the nature of Dark Matter and Dark Energy. On the theoretical side, recent advances in the use of 3D information of the sources from photometric redshifts promise greater statistical power, and these are further enhanced by the use of statistics beyond two-point quantities such as the power spectrum. The use of 3D information also alleviates difficulties arising from physical effects such as the intrinsic alignment of galaxies, which can mimic weak lensing to some extent. On the observational side, in the next few years weak lensing surveys such as CFHTLS, VST-KIDS and Pan-STARRS, and the planned Dark Energy Survey, will provide the first weak lensing surveys covering very large sky areas and depth. In the long run even more ambitious programmes such as DUNE, the Supernova Anisotropy Probe (SNAP) and Large-aperture Synoptic Survey Telescope (LSST) are planned. Weak lensing of diffuse components such as the CMB and 21 cm emission can also

  6. Solutions on a high-speed wide-angle zoom lens with aspheric surfaces

    Science.gov (United States)

    Yamanashi, Takanori

    2012-10-01

    Recent development in CMOS and digital camera technology has accelerated the business and market share of digital cinematography. In terms of optical design, this technology has increased the need to carefully consider pixel pitch and characteristics of the imager. When the field angle at the wide end, zoom ratio, and F-number are specified, choosing an appropriate zoom lens type is crucial. In addition, appropriate power distributions and lens configurations are required. At points near the wide end of a zoom lens, it is known that an aspheric surface is an effective means to correct off-axis aberrations. On the other hand, optical designers have to focus on manufacturability of aspheric surfaces and perform required analysis with respect to the surface shape. Centration errors aside, it is also important to know the sensitivity to aspheric shape errors and their effect on image quality. In this paper, wide angle cine zoom lens design examples are introduced and their main characteristics are described. Moreover, technical challenges are pointed out and solutions are proposed.

  7. Registration of eye reflection and scene images using an aspherical eye model.

    Science.gov (United States)

    Nakazawa, Atsushi; Nitschke, Christian; Nishida, Toyoaki

    2016-11-01

    This paper introduces an image registration algorithm between an eye reflection and a scene image. Although there are currently a large number of image registration algorithms, this task remains difficult due to nonlinear distortions at the eye surface and large amounts of noise, such as iris texture, eyelids, eyelashes, and their shadows. To overcome this issue, we developed an image registration method combining an aspherical eye model that simulates nonlinear distortions considering eye geometry and a two-step iterative registration strategy that obtains dense correspondence of the feature points to achieve accurate image registrations for the entire image region. We obtained a database of eye reflection and scene images featuring four subjects in indoor and outdoor scenes and compared the registration performance with different asphericity conditions. Results showed that the proposed approach can perform accurate registration with an average accuracy of 1.05 deg by using the aspherical cornea model. This work is relevant for eye image analysis in general, enabling novel applications and scenarios.

  8. Intraocular Inflammation Associated with Ocular Toxoplasmosis : Relationships at Initial Examination

    NARCIS (Netherlands)

    Dodds, Emilio M.; Holland, Gary N.; Stanford, Miles R.; Yu, Fei; Siu, Willie O.; Shah, Kayur H.; Loon, Ninette Ten Dam-Van; Muccioli, Cristina; Hovakimyan, Anna; Barisani-Asenbauer, Talin

    2008-01-01

    PURPOSE: To describe characteristics of intraocular inflammation in eyes with active ocular toxoplasmosis and to identify relationships between signs of inflammation, complications (including elevated intraocular pressure [IOP]), other disease features, and host characteristics. DESIGN: Multicenter,

  9. Lente intra-ocular opaca em diplopia intratável: relato de caso Opaque intraocular lens in intractable diplopia: case report

    Directory of Open Access Journals (Sweden)

    Fernanda Teixeira Krieger

    2006-08-01

    Full Text Available Diplopia intratável tem sido descrita em várias situações. Métodos convencionais como prismas e correção cirúrgica do estrabismo falham em neutralizá-la. O objetivo do trabalho é documentar o caso de uma paciente com estrabismo de longa data, cuja diplopia deteriorou-se ao longo dos anos, e não foi possível resolução com cirurgia, prisma, e oclusão com óculos e lente de contato com pupila opaca. A paciente foi então submetida à facoemulsificação com implante de lente intra-ocular opaca que atingiu o objetivo desejado.Intractable diplopia has been described in many situations but poor results are the rule with standard treatment modalities. The authors report a case of a woman with long-standing strabismus and diplopia who failed to improve following surgery, prism, and occlusive spectacles or contact lenses. Then, she was submitted to phacoemulsification and opaque intraocular lens implantation, which successfully neutralized diplopia.

  10. Statistics of gravitational lenses. III. Astrophysical consequences of quasar lensing

    International Nuclear Information System (INIS)

    Ostriker, J.P.; Vietri, M.

    1986-01-01

    The method of Schmidt and Green (1983) for calculating the luminosity function of quasars is combined with gravitational-lensing theory to compute expected properties of lensed systems. Multiple quasar images produced by galaxies are of order 0.001 of the observed quasars, with the numbers over the whole sky calculated to be (0.86, 120, 1600) to limiting B magnitudes of (16, 19, 22). The amount of false evolution is small except for an interesting subset of apparently bright, large-redshift objects for which minilensing by starlike objects may be important. Some of the BL Lac objects may be in this category, with the galaxy identified as the parent object really a foreground object within which stars have lensed a background optically violent variable quasar. 24 references

  11. Ab-interno scleral suture loop fixation with cow-hitch knot in posterior chamber intraocular lens decentration

    Directory of Open Access Journals (Sweden)

    Ertugrul Can

    2016-01-01

    Full Text Available Aim of Study: To describe a simplified ab-interno cow-hitch suture fixation technique for repositioning decentered posterior chamber intraocular lens (PC IOL. Materials and Methods: Two cases are presented with the surgical correction of decentered and subluxated IOL. Ab-interno scleral suture fixation technique with hitch-cow knot in the eye was performed with a ciliary sulcus guide instrument and 1 year follow-up was completed. Results: Both of the patients had well centered lenses postoperatively. Corrected distant and near visual acuities of the patients were improved. There was no significant postoperative complication. In the follow-up period of 1 year, no evidence of suture erosion was found. Conclusions: Ab-interno scleral suture loop fixation with hitch-cow knot in the eye was effective in repositioning decentered or subluxated PC IOLs with excellent postoperative centered lenses and visual outcomes.

  12. Commercial air travel after intraocular gas injection.

    Science.gov (United States)

    Houston, Stephen; Graf, Jürgen; Sharkey, James

    2012-08-01

    Passengers with intraocular gas are at risk of profound visual loss when exposed to reduced absolute pressure within the cabin of a typical commercial airliner. Information provided on the websites of the world's 10 largest airlines offer a considerable range of opinion as to when it might be safe to fly after gas injection. Physicians responsible for clearing pseassengers as 'fit to fly' should be aware modern retinal surgical techniques increasingly employ long-acting gases as vitreous substitutes. The kinetics of long-acting intraocular gases must be considered when deciding how long after surgery it is safe to travel. It is standard practice to advise passengers not to fly in aircraft until the gas is fully resorbed. To achieve this, it may be necessary to delay travel for approximately 2 wk after intraocular injection of sulfur hexafluoride (SF6) and for 6 wk after injection of perfluoropropane (C3F8).

  13. Importance of intraocular pressure in glaucoma

    Science.gov (United States)

    Joos, Karen M.

    1999-06-01

    Glaucoma results in permanent vision loss and affects the peripheral vision initially. It is presented in 22.5 million people worldwide and is the 3rd cause of blindness. Present tonometers are not ideal for intraocular pressure measurements in all eyes. Of concern, PRK and LASIK may result in lower intraocular pressure readings. A challenges now exists for the development of a tonometer which can easily compensate for corneas with many parameters to avoid a future increase in normal-tension glaucoma or glaucoma which is advanced.

  14. Contact Lenses for Color Blindness.

    Science.gov (United States)

    Badawy, Abdel-Rahman; Hassan, Muhammad Umair; Elsherif, Mohamed; Ahmed, Zubair; Yetisen, Ali K; Butt, Haider

    2018-06-01

    Color vision deficiency (color blindness) is an inherited genetic ocular disorder. While no cure for this disorder currently exists, several methods can be used to increase the color perception of those affected. One such method is the use of color filtering glasses which are based on Bragg filters. While these glasses are effective, they are high cost, bulky, and incompatible with other vision correction eyeglasses. In this work, a rhodamine derivative is incorporated in commercial contact lenses to filter out the specific wavelength bands (≈545-575 nm) to correct color vision blindness. The biocompatibility assessment of the dyed contact lenses in human corneal fibroblasts and human corneal epithelial cells shows no toxicity and cell viability remains at 99% after 72 h. This study demonstrates the potential of the dyed contact lenses in wavelength filtering and color vision deficiency management. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Lensing smoothing of BAO wiggles

    Energy Technology Data Exchange (ETDEWEB)

    Dio, Enea Di, E-mail: enea.didio@oats.inaf.it [INAF—Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, I-34143 Trieste (Italy)

    2017-03-01

    We study non-perturbatively the effect of the deflection angle on the BAO wiggles of the matter power spectrum in real space. We show that from redshift z ∼2 this introduces a dispersion of roughly 1 Mpc at BAO scale, which corresponds approximately to a 1% effect. The lensing effect induced by the deflection angle, which is completely geometrical and survey independent, smears out the BAO wiggles. The effect on the power spectrum amplitude at BAO scale is about 0.1 % for z ∼2 and 0.2 % for z ∼4. We compare the smoothing effects induced by the lensing potential and non-linear structure formation, showing that the two effects become comparable at z ∼ 4, while the lensing effect dominates for sources at higher redshifts. We note that this effect is not accounted through BAO reconstruction techniques.

  16. VISUAL ACUITY AND CLINICAL REFRACTION FOLLOWING IMPLANTATION OF VARIOUS MULTIFOCAL INTRAOCULAR LENSES

    Directory of Open Access Journals (Sweden)

    N. N. Temirov

    2015-01-01

    Full Text Available Aim. To analyze visual acuity, clinical refraction, and defocusing tolerance after the implantation of monofocal IOL with rotational asymmetric optic (Lentis Mplus 313 MF compared with Acrysof ReSTOR SN6AD1.Materials and methods. Phacoemulsification was performed in a total of 194 patients (288 eyes, i.e., 144 patients (188 eyes with cataract and 50 patients (100 eyes with presbyopia and high ametropia. The patients were divided into two groups. Study group included 132 patients (194 eyes implanted with Lentis Mplus while control group included 62 patients (94 eyes implanted with Acrysof ReSTOR. Uncorrected distance (5 m, intermediate (50‑70 cm, and near (20‑40 cm visual acuity under photopic (85 cd/m2 and mesopic (8 cd/m2 conditions were measured, objective and subjective refractometry were performed, and defocusing tolerance was evaluated.Results. Postoperatively, uncorrected distance and near visual acuity was high while intermediate visual acuity was moderately low. Lentis Mplus patients had better near and intermediate visual acuity under mesopic conditions as compared with Acrysof ReSTOR patients. Emmetropia (target refraction was achieved in 90.2% of study group patients and in 87.2% of control group patients. In patients implanted with Lentis Mplus, refraction was measured by subjective method. Optimal A-constant for Lentis Mplus and Acrysof ReSTOR was 118.0 and 118.6, respectively. Under defocusing, Lentis Mplus patients had better visual acuity than Acrysof ReSTOR patients. This indirectly confirms better intermediate vision.Conclusions. Lentis Mplus provides better vision at various distances that does not almost depend on light levels and induces minimal dysphotopsia. 

  17. Intraocular pressure readings obtained through soft contact lenses using four types of tonometer

    OpenAIRE

    Takenaka J; Kunihara E; Rimayanti U; Tanaka J; Kaneko M; Kiuchi Y

    2015-01-01

    Joji Takenaka,1 Eriko Kunihara,1 Ulfah Rimayanti,2 Junko Tanaka,3 Makoto Kaneko,4 Yoshiaki Kiuchi1 1Department of Ophthalmology and Visual Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan; 2Faculty of Medicine and Health Sciences, UIN Alauddin Makassar, South Sulawesi, Indonesia; 3Department of Epidemiology, Infectious Disease Control and Prevention, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan; 4Graduate Schoo...

  18. Gravitational lensing by spinning and radially moving lenses

    International Nuclear Information System (INIS)

    Sereno, M.

    2002-01-01

    The effect of currents of mass on bending of light rays is considered in the weak field regime. Following Fermat's principle and the standard theory of gravitational lensing, we derive the gravito-magnetic correction to time delay function and deflection angle caused by a geometrically-thin lens. The cases of both rotating and shifting deflectors are discussed

  19. Intraocular foreign-body hazard during vitrectomy.

    Science.gov (United States)

    Bovino, J A; Marcus, D F

    1982-03-01

    We noted two instances of forceps-induced fragmentation of the bar used for scleral plug storage during vitreous surgery. The silicone bar material was adherent to the plug in both cases. Because this represents a significant intraocular foreign body hazard, the scleral plug should be carefully inspected before insertion.

  20. Fundus autofluorescence patterns in primary intraocular lymphoma.

    Science.gov (United States)

    Casady, Megan; Faia, Lisa; Nazemzadeh, Maryam; Nussenblatt, Robert; Chan, Chi-Chao; Sen, H Nida

    2014-02-01

    To evaluate fundus autofluorescence (FAF) patterns in patients with primary intraocular (vitreoretinal) lymphoma. Records of all patients with primary intraocular lymphoma who underwent FAF imaging at the National Eye Institute were reviewed. Fundus autofluorescence patterns were evaluated with respect to clinical disease status and the findings on fluorescein angiography and spectral-domain optical coherence tomography. There were 18 eyes (10 patients) with primary intraocular lymphoma that underwent FAF imaging. Abnormal autofluorescence in the form of granular hyperautofluorescence and hypoautofluorescence was seen in 11 eyes (61%), and blockage by mass lesion was seen in 2 eyes (11%). All eyes with granular pattern on FAF had active primary intraocular lymphoma at the time of imaging, but there were 5 eyes with unremarkable FAF, which were found to have active lymphoma. The most common pattern on fluorescein angiography was hypofluorescent round spots with a "leopard spot" appearance (43%). These hypofluorescent spots on fluorescein angiography correlated with hyperautofluorescent spots on FAF in 5 eyes (36%) (inversion of FAF). Nodular hyperreflective spots at the level of retinal pigment epithelium on optical coherence tomography were noted in 43% of eyes. The hyperautofluorescent spots on FAF correlated with nodular hyperreflective spots on optical coherence tomography in 6 eyes (43%). Granularity on FAF was associated with active lymphoma in majority of the cases. An inversion of FAF (hyperautofluorescent spots on FAF corresponding to hypofluorescent spots on fluorescein angiography) was observed in less than half of the eyes.

  1. Visual performance after the implantation of a new trifocal intraocular lens

    Directory of Open Access Journals (Sweden)

    Vryghem JC

    2013-10-01

    intraocular lenses improves the intermediate vision with minimal visual discomfort for the patient.Keywords: lens implantation, trifocal diffractive intraocular lens, third focus, diffractive multifocal

  2. Probing supervoids with weak lensing

    Science.gov (United States)

    Higuchi, Yuichi; Inoue, Kaiki Taro

    2018-05-01

    The cosmic microwave background (CMB) has non-Gaussian features in the temperature fluctuations. An anomalous cold spot surrounded with a hot ring, called the Cold Spot, is one of such features. If a large underdense region (supervoid) resides towards the Cold Spot, we would be able to detect a systematic shape distortion in the images of background source galaxies via weak lensing effect. In order to estimate the detectability of such signals, we used the data of N-body simulations to simulate full-sky ray-tracing of source galaxies. We searched for a most prominent underdense region using the simulated convergence maps smoothed at a scale of 20° and obtained tangential shears around it. The lensing signal expected in a concordant Λ cold dark matter model can be detected at a signal-to-noise ratio S/N ˜ 3. If a supervoid with a radius of ˜200 h-1 Mpc and a density contrast δ0 ˜ -0.3 at the centre resides at a redshift z ˜ 0.2, on-going and near-future weak gravitational lensing surveys would detect a lensing signal with S/N ≳ 4 without resorting to stacking. From the tangential shear profile, we can obtain a constraint on the projected mass distribution of the supervoid.

  3. Weak lensing and dark energy

    International Nuclear Information System (INIS)

    Huterer, Dragan

    2002-01-01

    We study the power of upcoming weak lensing surveys to probe dark energy. Dark energy modifies the distance-redshift relation as well as the matter power spectrum, both of which affect the weak lensing convergence power spectrum. Some dark-energy models predict additional clustering on very large scales, but this probably cannot be detected by weak lensing alone due to cosmic variance. With reasonable prior information on other cosmological parameters, we find that a survey covering 1000 sq deg down to a limiting magnitude of R=27 can impose constraints comparable to those expected from upcoming type Ia supernova and number-count surveys. This result, however, is contingent on the control of both observational and theoretical systematics. Concentrating on the latter, we find that the nonlinear power spectrum of matter perturbations and the redshift distribution of source galaxies both need to be determined accurately in order for weak lensing to achieve its full potential. Finally, we discuss the sensitivity of the three-point statistics to dark energy

  4. Optics Demonstrations Using Cylindrical Lenses

    Science.gov (United States)

    Ivanov, Dragia; Nikolov, Stefan

    2015-01-01

    In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

  5. Scientific visualization of gravitational lenses

    International Nuclear Information System (INIS)

    Magallon, M.

    1999-01-01

    Concepts related to gravitational lenses are discussed and applied to develop an interactive visualization tool that allow us to investigate them. Optimization strategies were performed to elaborate the tool. Some results obtained from the application of the tool are shown [es

  6. Neodymium:YAG laser cutting of intraocular lens haptics in vitro and in vivo.

    Science.gov (United States)

    Feder, J M; Rosenberg, M A; Farber, M D

    1989-09-01

    Various complications following intraocular lens (IOL) surgery result in explantation of the lenses. Haptic fibrosis may necessitate cutting the IOL haptics prior to removal. In this study we used the neodymium: YAG (Nd:YAG) laser to cut polypropylene and poly(methyl methacrylate) (PMMA) haptics in vitro and in rabbit eyes. In vitro we were able to cut 100% of both haptic types successfully (28 PMMA and 30 polypropylene haptics). In rabbit eyes we were able to cut 50% of the PMMA haptics and 43% of the polypropylene haptics. Poly(methyl methacrylate) haptics were easier to cut in vitro and in vivo than polypropylene haptics, requiring fewer shots for transection. Complications of Nd:YAG laser use frequently interfered with haptic transections in rabbit eyes. Haptic transection may be more easily accomplished in human eyes.

  7. Optical ensemble analysis of intraocular lens performance through a simulated clinical trial with ZEMAX.

    Science.gov (United States)

    Zhao, Huawei

    2009-01-01

    A ZEMAX model was constructed to simulate a clinical trial of intraocular lenses (IOLs) based on a clinically oriented Monte Carlo ensemble analysis using postoperative ocular parameters. The purpose of this model is to test the feasibility of streamlining and optimizing both the design process and the clinical testing of IOLs. This optical ensemble analysis (OEA) is also validated. Simulated pseudophakic eyes were generated by using the tolerancing and programming features of ZEMAX optical design software. OEA methodology was verified by demonstrating that the results of clinical performance simulations were consistent with previously published clinical performance data using the same types of IOLs. From these results we conclude that the OEA method can objectively simulate the potential clinical trial performance of IOLs.

  8. Achromatic X-ray lenses

    International Nuclear Information System (INIS)

    Umbach, Marion

    2009-01-01

    This thesis presents first results on the development of achromatic refractive X-ray lenses which can be used for scientific experiments at synchrotron sources. First of all the different requirements for achromatic X-ray lenses have been worked out. There are different types of lenses, one type can be used for monochromatized sources when the energy is scanned while the spot size should be constant. The other type can be used at beamlines providing a broad energy band. By a combination of focusing and defocusing elements we have developed a lens system that strongly reduces the chromatic aberration of a refractive lens in a given energy range. The great challenge in the X-ray case - in contrast to the visible range - the complex refractive index, which is very similar for the possible materials in the X-ray spectrum. For precise studies a numerical code has been developed, which calculates the different rays on their way through the lenses to the detector plane via raytracing. In this numerical code the intensity distribution in the detector plane has been analyzed for a chromatic and the corresponding achromatic system. By optimization routines for the two different fields of applications specific parameter combinations were found. For the experimental verification an achromatic system has been developed, consisting of biconcave SU-8 lenses and biconvex Nickel Fresnel lenses. Their fabrication was based on the LIGA-process, including a further innovative development, namely the fabrication of two different materials on one wafer. In the experiment at the synchrotron source ANKA the energy was varied in a specific energy range in steps of 0.1 keV. The intensity distribution for the different energies was detected at a certain focal length. For the achromatic system a reduction of the chromatic aberration could be clearly shown. Achromatic refractive X-ray lenses, especially for the use at synchrotron sources, have not been developed so far. As a consequence of the

  9. Manufacturing and control of the aspherical mirrors for the telescope of the satellite Pleiades

    Science.gov (United States)

    Ducollet, Hélène; du Jeu, Christian; Fermé, Jean-Jacques

    2017-11-01

    For the Pleiades space program, SESO has been awarded the contract (fully completed), for the manufacturing of the whole set of telescope mirrors (4 mirrors, 2 flight models). These works did also include the mechanical design, manufacturing and mounting of the attachment flexures between the mirrors and the telescope main structure. This presentation is focused on the different steps of lightweighting, polishing, integration and control of these mirrors as well as a presentation of the existing SESO facilities and capabilities to produce such kind of aspherical components/sub-assemblies.

  10. Nucleosynthesis in neutrino-driven, aspherical supernova explosion of a massive star

    International Nuclear Information System (INIS)

    Fujimoto, S.; Hashimoto, M.; Ono, M.; Kotake, K.; Ohnishi, N.

    2011-01-01

    We examine explosive nucleosynthesis of p-nuclei during a delayed neutrino-driven, aspherical supernova explosion aided by standing accretion shock instability, based on two-dimensional hydrodynamic simulations of the explosion of a 15M · star. We find that p-nuclei are mainly produced through γ-processes, and that the nuclei lighter than 92 Mo are abundantly synthesized in slightly neutron-rich bubbles with electron fractions of Y e ≤0.48. 94 Mo, 96 Ru, and 98 Ru, are underproduced compared with the solar system, as in the spherical model.

  11. Postoperative Corneal Asphericity in Low, Moderate, and High Myopic Eyes After Transepithelial PRK Using a New Pulse Allocation.

    Science.gov (United States)

    Lin, David T C; Holland, Simon P; Verma, Shwetabh; Hogden, John; Arba-Mosquera, Samuel

    2017-12-01

    To evaluate the postoperative asphericity in low, moderate, and high myopic eyes after combined transepithelial photorefractive keratectomy and SmartSurf ACE treatment (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany). In this retrospective case series, the outcomes of myopic SmartSurf ACE were evaluated at 3 months postoperatively in 106 eyes and divided into low (less than -4.125 diopters [D]), moderate (-4.125 to -6.25 D), and high (more than -6.25 D) myopia groups. In all cases, standard examinations and preoperative and postoperative corneal topography (SCHWIND Sirius) were performed. The analysis comprised evaluating the change in asphericity versus planned correction, comparing expected and achieved postoperative asphericity for all eyes, and comparison of the three groups in terms of the preoperative and postoperatively expected and achieved asphericity. RESULTS At 3 months postoperatively, the low myopia group (n = 33) improved average negative asphericity (Q = -0.04 ± 0.17 preoperative vs -0.19 ± 0.20 postoperative, P .10), but showed significant differences postoperatively (P < .007). The cohort's average preoperative corrected distance visual acuity was 0.01 ± 0.04 logMAR (range: 0.0 to 0.18 logMAR) and uncorrected distance visual acuity was 0.03 ± 0.08 logMAR (range: -0.12 to 0.40 logMAR) 3 months postoperatively. SmartSurf ACE maintained or slightly improved preoperative corneal asphericity for low to moderate myopic corrections (up to -6.00 D). This may provide advantages in the quality of vision and the onset of presbyopic symptoms after laser refractive surgery in myopic patients. [J Refract Surg. 2017;33(12):820-826.]. Copyright 2017, SLACK Incorporated.

  12. EDITORIAL: Focus on Gravitational Lensing

    Science.gov (United States)

    Jain, Bhuvnesh

    2007-11-01

    Gravitational lensing emerged as an observational field following the 1979 discovery of a doubly imaged quasar lensed by a foreground galaxy. In the 1980s and '90s dozens of other multiply imaged systems were observed, as well as time delay measurements, weak and strong lensing by galaxies and galaxy clusters, and the discovery of microlensing in our galaxy. The rapid pace of advances has continued into the new century. Lensing is currently one of best techniques for finding and mapping dark matter over a wide range of scales, and also addresses broader cosmological questions such as understanding the nature of dark energy. This focus issue of New Journal of Physics presents a snapshot of current research in some of the exciting areas of lensing. It provides an occasion to look back at the advances of the last decade and ahead to the potential of the coming years. Just about a decade ago, microlensing was discovered through the magnification of stars in our galaxy by invisible objects with masses between that of Jupiter and a tenth the mass of the Sun. Thus a new component of the mass of our galaxy, dubbed MACHOs, was established (though a diffuse, cold dark matter-like component is still needed to make up most of the galaxy mass). More recently, microlensing led to another exciting discovery—of extra-solar planets with masses ranging from about five times that of Earth to that of Neptune. We can expect many more planets to be discovered through ongoing surveys. Microlensing is the best technique for finding Earth mass planets, though it is not as productive overall as other methods and does not allow for follow up observations. Beyond planet hunting, microlensing has enabled us to observe previously inaccessible systems, ranging from the surfaces of other stars to the accretion disks around the black holes powering distant quasars. Galaxies and galaxy clusters at cosmological distances can produce dramatic lensing effects: multiple images of background galaxies

  13. Sutureless intrascleral intraocular lens fixation with lamellar dissection of scleral tunnel

    Directory of Open Access Journals (Sweden)

    Kawaji T

    2016-01-01

    Full Text Available Takahiro Kawaji,1,2 Tomoki Sato,2 Hidenobu Tanihara11Department of Ophthalmology, Faculty of Life Sciences, Kumamoto University, Chuo-ku, 2Sato Eye & Internal Medicine Clinic, Kumamoto, JapanPurpose: To report the results of sutureless scleral fixation of a posterior chamber intraocular lens (IOL by using our developed simple technique.Methods: We retrospectively reviewed the medical records of 48 eyes of 47 patients who underwent sutureless intrascleral IOL fixation by using our modified technique. A 25-gauge microvitreoretinal knife was used to perform sclerotomies and create limbus-parallel scleral tunnels with lamellar dissection in which the haptics were fixed.Results: The IOLs were fixed and centered well. The mean follow-up period was 26.7 months. Postoperative complications included smooth vitreous hemorrhage in four eyes (8.3%, cystoid macular edema in two eyes (4.2%, and iris capture of the IOL in two eyes (4.2%. No other complications, such as breakage of the IOL, spontaneous IOL dislocation, or retinal detachment, were detected during the follow-up period.Conclusion: The lamellar dissection of the limbus-parallel scleral tunnel can simplify the forceps-assisted introduction of the haptics into the scleral tunnel, and this technique seemed to be safe.Keywords: intraocular lenses, ophthalmologic surgical procedures, intrascleral fixation, sutureless fixation

  14. Black diaphragm intraocular lens implantation and penetrating keratoplasty in aphakic eyes with traumatic aniridia

    Directory of Open Access Journals (Sweden)

    Xiao-Guang Dong

    2013-04-01

    Full Text Available AIM: To evaluate the long-term outcome of implantation of black diaphragm intraocular (BDI lens combined with penetrating keratoplasty (PKP for managing aphakic eyes with traumatic aniridia and corneal damage. METHODS: Six aphakic eyes of six patients with traumatic aniridia and corneal damage had BDI lens implantation at Qingdao Eye Hospital, Shandong Eye Institute from June 2008 to November 2011. Medical records of the patients were reviewed. Three patients received PKP and after 12-18months were implanted with BDI lens. The other three patients completed PKP and BDI lens implantation at the same time. The corrected visual acuity, intraocular pressure and number of corneal endothelial cells were monitored. RESULTS: The patients were followed up for an average of 24.3±12.1months (range 14-48 months. All BDI lenses were located well. The best corrected visual acuity got improved in 5 patients (0.1-1.0 and decreased in 1 patient from 0.4 to 0.2. Three patients had normal intraocular pressure (IOP after implantation. Two patients required antiglaucoma medications to control IOP within the normal range and 1 patient implanted Ahmed glaucoma valve to control IOP. The corneal grafts kept transparent in all eyes and the corneal endothelial counting >1 000/mm2, although two patients experienced acute graft rejection and loss more than 30% corneal endothelial cells. CONCLUSION: Implantation of BDI lens combined with PKP is an effective option for managing aphakic eyes with traumatic aniridia and corneal damage. Although the results in our study are encouraging, additional studies of the long-term safety and efficacy are required. A larger study population and longer follow-up may be beneficial.

  15. Phakic iris-fixated intraocular lens placement in the anterior chamber: effects on aqueous flow.

    Science.gov (United States)

    Repetto, Rodolfo; Pralits, Jan O; Siggers, Jennifer H; Soleri, Paolo

    2015-05-01

    Phakic intraocular lenses (pIOLs) are used for correcting vision; in this paper we investigate the fluid dynamical effects of an iris-fixated lens in the anterior chamber. In particular, we focus on changes in the wall shear stress (WSS) on the cornea and iris, which could be responsible for endothelial and pigment cell loss, respectively, and also on the possible increase of the intraocular pressure, which is known to correlate with the incidence of secondary glaucoma. We use a mathematical model to study fluid flow in the anterior chamber in the presence of a pIOL. The governing equations are solved numerically using the open source software OpenFOAM. We use an idealized standard geometry for the anterior chamber and a realistic geometric description of the pIOL. We consider separately the main mechanisms that produce fluid flow in the anterior chamber. The numerical simulations allow us to obtain a detailed description of the velocity and pressure distribution in the anterior chamber, and indicated that implantation of the pIOL significantly modifies the fluid dynamics in the anterior chamber. However, lens implantation has negligible influence on the intraocular pressure and does not produce a significant increase of the shear stress on the cornea, while the shear stress on the iris, although increased, is not enough to cause detachment of cells. We conclude that alterations in the fluid dynamics in the anterior chamber as a result of lens implantation are unlikely to be the cause of medical complications associated with its use.

  16. Using a slit lamp-mounted digital high-speed camera for dynamic observation of phakic lenses during eye movements: a pilot study

    Directory of Open Access Journals (Sweden)

    Leitritz MA

    2014-07-01

    Full Text Available Martin Alexander Leitritz, Focke Ziemssen, Karl Ulrich Bartz-Schmidt, Bogomil Voykov Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University of Tübingen, Tübingen, Germany Purpose: To evaluate a digital high-speed camera combined with digital morphometry software for dynamic measurements of phakic intraocular lens movements to observe kinetic influences, particularly in fast direction changes and at lateral end points. Materials and methods: A high-speed camera taking 300 frames per second observed movements of eight iris-claw intraocular lenses and two angle-supported intraocular lenses. Standardized saccades were performed by the patients to trigger mass inertia with lens position changes. Freeze images with maximum deviation were used for digital software-based morphometry analysis with ImageJ.Results: Two eyes from each of five patients (median age 32 years, range 28–45 years without findings other than refractive errors were included. The high-speed images showed sufficient usability for further morphometric processing. In the primary eye position, the median decentrations downward and in a lateral direction were -0.32 mm (range -0.69 to 0.024 and 0.175 mm (range -0.37 to 0.45, respectively. Despite the small sample size of asymptomatic patients, we found a considerable amount of lens dislocation. The median distance amplitude during eye movements was 0.158 mm (range 0.02–0.84. There was a slight positive corrlation (r=0.39, P<0.001 between the grade of deviation in the primary position and the distance increase triggered by movements.Conclusion: With the use of a slit lamp-mounted high-speed camera system and morphometry software, observation and objective measurements of iris-claw intraocular lenses and angle-supported intraocular lenses movements seem to be possible. Slight decentration in the primary position might be an indicator of increased lens mobility during kinetic stress during eye movements

  17. New case of gravitational lensing

    Energy Technology Data Exchange (ETDEWEB)

    Surdej, J.; Swings, J.-P.; Magain, P.; Borgeest, U.; Kayser, R.; Refsdal, S.; Courvoisier, T.J.-L.; Kellermann, K.I.; Kuehr, H.

    1987-10-22

    The authors report a brief description of a gravitational lens system UM673 = Q0142 - 100 = PHL3703. It consists of two images, A and B, separated by 2.2 arc s at a redshift zsub(q) = 2.719. The lensing galaxy has also been found. It lies very near the line connecting the two QSO (quasi-stellar objects) images, approx. 0.8 arc s from the fainter one. Application of gravitational optometry to this system leads to a value Msub(o) or approx. = 2.4 x 10/sup 11/ M solar masses for the mass of the lensing galaxy and to ..delta..t approx. 7 weeks for the most likely travel-time difference between the two light paths to the QSO.

  18. Intraocular pressure menagement with transpalpebral tonometry

    OpenAIRE

    Toker, Mustafa İlker; Dursun, Ayhan

    2013-01-01

    Applanation tonometry is the method of measuring intraocular pressure (IOP) with instruments the corneal surface. The Goldmann applanation tonometer (GAT) is regarded as the “gold standard’’ of measuring IOP. An irregular and opaque corneal surface compromises IOP measurement by Goldmann applanation tonometry. In such cases accurate measurement without corneal contact would be applicable. The transpalpebral tonometer is new method and measures IOP without corneal contact through the eyelid....

  19. A system of catoptric lenses

    International Nuclear Information System (INIS)

    McFarland, P.J.; Rambauske, W.R.

    1973-01-01

    Description is given of a system of catoptric lenses for combining energies provided by a certain number of sources, e.g. optical energies provided by a certain number of lasers. This system comprises sets of mirrors the reflecting surfaces of which have their focuses spaced from a common axis. The mirrors of all these sets are arranged on a common frame, which makes aperture-locking impossible. This can be applied to thermonuclear fusion [fr

  20. Effect of an ultraviolet-filtering intraocular lens on cystoid macular edema

    Energy Technology Data Exchange (ETDEWEB)

    Kraff, M.C.; Sanders, D.R.; Jampol, L.M.; Lieberman, H.L.

    1985-03-01

    A prospective double-masked study of 301 patients was undertaken to compare the effect of ultraviolet (UV) filtering in implant intraocular lenses (IOL) on the angiographic incidence of cystoid macular edema (CME) in patients undergoing extracapsular cataract extraction. Patients were randomized to receive either a posterior chamber IOL that contained UV-absorbing chromophore or an identical IOL which did not contain such a chromophore. All patients were scheduled for fluorescein angiography between three and six months after surgery; 228 angiograms were obtained that were readable for the presence or absence of angiographic CME. The mean interval following surgery was 4.3 months. The incidence of CME was 18.8% (21 of 112) in patients who received lenses without UV-filtering chromophore and 9.5% (11 of 116) in patients who received IOLs that contained UV-filtering chromophore. These findings show that UV-filtering-IOLs resulted in a statistically significant decrease in the incidence of CME. The presence or absence of the UV-filtering chromophore did not, however, significantly affect visual acuity in the early postoperative period.

  1. [Changes in intraocular pressure depending on posture].

    Science.gov (United States)

    Barac, Ramona; Pop, Monica; Tătaru, C; Gheorghe, A; Bădescu, Silvia; Stanciu, Maria; Burcea, M

    2014-01-01

    Glaucoma is an important eye disease that, left untreated, causes irreversible blindness by affecting optic nerve threads. Decreasing intraocular pressure and maintaining it at a low level throughout the day is one of the objectives of antiglaucoma therapy. This is a prospective study conducted on a sample of 80 patients who presented at "Emergency Eye Hospital" Bucharest between 1st of December 2013 30th of July 2014. Patients were divided into two groups: 40 patients with glaucoma and 40 patients without glaucoma (control group). THE OBJECTIVE OF THE STUDY: To determine changes in intraocular pressure that may occur depending on body posture and the correlations between changes in intraocular pressure and glaucoma, obesity, hypertension. These IOP changes may be important in the progression of glaucoma regarding that one third of our time is spent on supine position during night. RESULTS AND CONCLUZIONS: IOP varies from sitting down to supine position. IOP increases in supine in most patients (with or without glaucoma) with an average of 1.25 mmHg. The increase among patients with glaucoma is higher (1.67 mmHg) compared to those without glaucoma (0.82 mmHg). In patients with hypertension and glaucoma, IOP increased with 2.62 mmHg. In patients with hypertension and obesity IOP increased with 2.5 mmHg.

  2. Mean intraocular pressure in hypertensive adults

    International Nuclear Information System (INIS)

    Irum, S.; Malik, A.M.; Saeed, M.

    2015-01-01

    To determine the mean Intraocular Pressure (IOP) in already diagnosed adult hypertensive patients with different grades of hypertension. Study Design: Cross-sectional descriptive study. Place and Duration of Study: Combined Military Hospital, Lahore, from March 2012 to Aug 2012. Patients and Methods: A total of 178 already diagnosed hypertensive patients were selected. A detailed history of ocular or systemic diseases was taken. Intraocular pressure was measured with help of Goldmann applanation tonometer. Three consecutive readings of IOP of each eye were taken at 30 minutes interval and mean calculated. Blood pressure was recorded in seated position from right upper arm, by mercury sphygmomanometer. Blood pressure measurements were determined by taking the mean value of three systolic and diastolic readings. Results: The results of intraocular pressure (IOP) between various grades of hypertension were determined. There was an increase in mean IOP with rise in blood pressure. The subjects with grade I hypertension showed a mean IOP of 13.95 ± 3.74 mmHg, while grade II and grade III hypertensive subjects had mean IOPs as 18.10 ± 3.32 and 20.21 ± 2.52 mmHg respectively. Conclusion: A higher value of mean IOP was found with increase in systolic and diastolic blood pressures. (author)

  3. Gravitational lensing in plasmic medium

    Energy Technology Data Exchange (ETDEWEB)

    Bisnovatyi-Kogan, G. S., E-mail: gkogan@iki.rssi.ru; Tsupko, O. Yu., E-mail: tsupko@iki.rssi.ru [Russian Academy of Sciences, Space Research Institute (Russian Federation)

    2015-07-15

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.

  4. Tomographic inversion of P and pP data for aspherical mantle structure below the northwest Pacific region

    NARCIS (Netherlands)

    Hilst, R.D. van der; Engdahl, E.R.; Spakman, W.

    1993-01-01

    To investigate the morphology of subducted slab in the mantle below northwest Pacific island arcs we inverted traveltime residuals for aspherical variations in P-wave propagation velocity relative to the radially symmetric iasp91 reference model. The tomographic method used is based on a step-wise

  5. Avoiding unstable regions in the design space of EUV mirror systems comprising high-order aspheric surfaces

    NARCIS (Netherlands)

    Marinescu, O.; Bociort, F.; Braat, J.

    2004-01-01

    When Extreme Ultraviolet mirror systems having several high-order aspheric surfaces are optimized, the configurations often enter into highly unstable regions of the parameter space. Small changes of system parameters lead then to large changes in ray paths, and therefore optimization algorithms

  6. 30 CFR 18.30 - Windows and lenses.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed in...

  7. Planck 2015 results. XV. Gravitational lensing

    CERN Document Server

    Ade, P.A.R.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Bartolo, N.; Basak, S.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J.J.; Bonaldi, A.; Bonavera, L.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R.C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Diego, J.M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T.A.; Eriksen, H.K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A.A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J.E.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Hurier, G.; Jaffe, A.H.; Jaffe, T.R.; Jones, W.C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Lewis, A.; Liguori, M.; Lilje, P.B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P.M.; Macías-Pérez, J.F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P.G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Nørgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Popa, L.; Pratt, G.W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J.P.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rowan-Robinson, M.; Rubiño-Martín, J.A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Spencer, L.D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J.A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L.A.; Wandelt, B.D.; Wehus, I.K.; White, M.; Yvon, D.; Zacchei, A.

    2016-01-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40 sigma), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator we detect lensing at a significance of 5 sigma. We cross-check the accuracy of our measurement using the wide frequency coverage and complementarity of the temperature and polarization measurements. Public products based on this measurement include an estimate of the lensing potential over approximately 70% of the sky, an estimate of the lensing potential power spectrum in bandpowers for the multipole range 40lensing potential power spectrum and that found in the best-fitting LCDM model based on the Planck temperature and polarization power spectra. Using the lensing likelihood alone we obtain a percent-level measurement of ...

  8. Clinical Outcomes after Uncomplicated Cataract Surgery with Implantation of the Tecnis Toric Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Wojciech Lubiński

    2016-01-01

    Full Text Available Purpose. To evaluate the clinical outcomes after uncomplicated cataract surgery with implantation of an aspheric toric intraocular lens (IOL during a 6-month follow-up. Methods. Prospective study including 27 consecutive eyes of 18 patients (mean age: 66.1±11.4 years with a visually significant cataract and corneal astigmatism ≥ 0.75 D and undergoing uncomplicated cataract surgery with implantation of the Tecnis ZCT toric IOL (Abbott Medical Optics. Visual, refractive, and keratometric outcomes as well as IOL rotation were evaluated during a 6-month follow-up. At the end of the follow-up, patient satisfaction and perception of optical/visual disturbances were also evaluated using a subjective questionnaire. Results. At 6 months after surgery, mean LogMAR uncorrected (UDVA and corrected distance visual acuity (CDVA were 0.19±0.12 and 0.14±0.10, respectively. Postoperative UDVA of 20/40 or better was achieved in 92.6% of eyes. Mean refractive cylinder decreased significantly from −3.73±1.96 to −1.42±0.88 D (p<0.001, while keratometric cylinder did not change significantly (p=0.44. Mean absolute IOL rotation was 1.1±2.4°, with values of more than 5° in only 2 eyes (6.9%. Mean patient satisfaction score was 9.70±0.46, using a scale from 0 (not at all satisfied to 10 (very satisfied. No postoperative optical/visual disturbances were reported. Conclusion. Cataract surgery with implantation of the Tecnis toric IOL is an effective method of refractive correction in eyes with corneal astigmatism due to the good IOL positional stability, providing high levels of patient’s satisfaction.

  9. Fixed mydriatic pupil associated with an intraocular pressure rise as a complication of the implant of a Phakic Refractive Lens (PRL).

    Science.gov (United States)

    Pérez-Cambrodí, Rafael José; Piñero-Llorens, David Pablo; Ruiz-Fortes, Juan Pedro; Blanes-Mompó, Francisco Javier; Cerviño-Expósito, Alejandro

    2014-07-01

    We describe a case report of a patient that was implanted with a posterior chamber phakic intraocular lens (Phakic Refractive Lens, PRL) for the correction of moderate myopia and who developed postoperatively a fixed mydriasis compatible with an Urrets-Zavalia Syndrome (UZS). Specifically, a sudden acute increase of IOP in the left eye was observed in the immediate postoperative period. After IOP stabilization, the refractive result was good, but a fixed and mydriatic pupil appeared. This condition led the patient to experience visual discomfort, halos, and glare associated with high levels of higher-order aberrations in spite of the good visual result. A tinted-contact lens was fitted in order to minimize those symptoms. The UZS should be considered as a possible complication after implantation of posterior chamber phakic intraocular lenses.

  10. Instrumental systematics and weak gravitational lensing

    International Nuclear Information System (INIS)

    Mandelbaum, R.

    2015-01-01

    We present a pedagogical review of the weak gravitational lensing measurement process and its connection to major scientific questions such as dark matter and dark energy. Then we describe common ways of parametrizing systematic errors and understanding how they affect weak lensing measurements. Finally, we discuss several instrumental systematics and how they fit into this context, and conclude with some future perspective on how progress can be made in understanding the impact of instrumental systematics on weak lensing measurements

  11. Factors influencing bacterial adhesion to contact lenses

    OpenAIRE

    Dutta, Debarun; Cole, Nerida; Willcox, Mark

    2012-01-01

    The process of any contact lens related keratitis generally starts with the adhesion of opportunistic pathogens to contact lens surface. This article focuses on identifying the factors which have been reported to affect bacterial adhesion to contact lenses. Adhesion to lenses differs between various genera/species/strains of bacteria. Pseudomonas aeruginosa, which is the predominant causative organism, adheres in the highest numbers to both hydrogel and silicone hydrogel lenses in vitro. The ...

  12. Intercomparison study and optical asphericity measurements of small ice particles in the CERN CLOUD experiment

    Directory of Open Access Journals (Sweden)

    L. Nichman

    2017-09-01

    Full Text Available Optical probes are frequently used for the detection of microphysical cloud particle properties such as liquid and ice phase, size and morphology. These properties can eventually influence the angular light scattering properties of cirrus clouds as well as the growth and accretion mechanisms of single cloud particles. In this study we compare four commonly used optical probes to examine their response to small cloud particles of different phase and asphericity. Cloud simulation experiments were conducted at the Cosmics Leaving OUtdoor Droplets (CLOUD chamber at European Organisation for Nuclear Research (CERN. The chamber was operated in a series of multi-step adiabatic expansions to produce growth and sublimation of ice particles at super- and subsaturated ice conditions and for initial temperatures of −30, −40 and −50 °C. The experiments were performed for ice cloud formation via homogeneous ice nucleation. We report the optical observations of small ice particles in deep convection and in situ cirrus simulations. Ice crystal asphericity deduced from measurements of spatially resolved single particle light scattering patterns by the Particle Phase Discriminator mark 2 (PPD-2K, Karlsruhe edition were compared with Cloud and Aerosol Spectrometer with Polarisation (CASPOL measurements and image roundness captured by the 3View Cloud Particle Imager (3V-CPI. Averaged path light scattering properties of the simulated ice clouds were measured using the Scattering Intensity Measurements for the Optical detectioN of icE (SIMONE and single particle scattering properties were measured by the CASPOL. We show the ambiguity of several optical measurements in ice fraction determination of homogeneously frozen ice in the case where sublimating quasi-spherical ice particles are present. Moreover, most of the instruments have difficulties of producing reliable ice fraction if small aspherical ice particles are present, and all of the instruments cannot

  13. Intercomparison study and optical asphericity measurements of small ice particles in the CERN CLOUD experiment

    Science.gov (United States)

    Nichman, Leonid; Järvinen, Emma; Dorsey, James; Connolly, Paul; Duplissy, Jonathan; Fuchs, Claudia; Ignatius, Karoliina; Sengupta, Kamalika; Stratmann, Frank; Möhler, Ottmar; Schnaiter, Martin; Gallagher, Martin

    2017-09-01

    Optical probes are frequently used for the detection of microphysical cloud particle properties such as liquid and ice phase, size and morphology. These properties can eventually influence the angular light scattering properties of cirrus clouds as well as the growth and accretion mechanisms of single cloud particles. In this study we compare four commonly used optical probes to examine their response to small cloud particles of different phase and asphericity. Cloud simulation experiments were conducted at the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at European Organisation for Nuclear Research (CERN). The chamber was operated in a series of multi-step adiabatic expansions to produce growth and sublimation of ice particles at super- and subsaturated ice conditions and for initial temperatures of -30, -40 and -50 °C. The experiments were performed for ice cloud formation via homogeneous ice nucleation. We report the optical observations of small ice particles in deep convection and in situ cirrus simulations. Ice crystal asphericity deduced from measurements of spatially resolved single particle light scattering patterns by the Particle Phase Discriminator mark 2 (PPD-2K, Karlsruhe edition) were compared with Cloud and Aerosol Spectrometer with Polarisation (CASPOL) measurements and image roundness captured by the 3View Cloud Particle Imager (3V-CPI). Averaged path light scattering properties of the simulated ice clouds were measured using the Scattering Intensity Measurements for the Optical detectioN of icE (SIMONE) and single particle scattering properties were measured by the CASPOL. We show the ambiguity of several optical measurements in ice fraction determination of homogeneously frozen ice in the case where sublimating quasi-spherical ice particles are present. Moreover, most of the instruments have difficulties of producing reliable ice fraction if small aspherical ice particles are present, and all of the instruments cannot separate perfectly

  14. Weak lensing of the Lyman α forest

    Science.gov (United States)

    Croft, Rupert A. C.; Romeo, Alessandro; Metcalf, R. Benton

    2018-06-01

    The angular positions of quasars are deflected by the gravitational lensing effect of foreground matter. The Lyman α (Lyα) forest seen in the spectra of these quasars is therefore also lensed. We propose that the signature of weak gravitational lensing of the Lyα forest could be measured using similar techniques that have been applied to the lensed cosmic microwave background (CMB), and which have also been proposed for application to spectral data from 21-cm radio telescopes. As with 21-cm data, the forest has the advantage of spectral information, potentially yielding many lensed `slices' at different redshifts. We perform an illustrative idealized test, generating a high-resolution angular grid of quasars (of order arcminute separation), and lensing the Lyα forest spectra at redshifts z = 2-3 using a foreground density field. We find that standard quadratic estimators can be used to reconstruct images of the foreground mass distribution at z ˜ 1. There currently exists a wealth of Lyα forest data from quasar and galaxy spectral surveys, with smaller sightline separations expected in the future. Lyα forest lensing is sensitive to the foreground mass distribution at redshifts intermediate between CMB lensing and galaxy shear, and avoids the difficulties of shape measurement associated with the latter. With further refinement and application of mass reconstruction techniques, weak gravitational lensing of the high-redshift Lyα forest may become a useful new cosmological probe.

  15. Photoflash unit having optical system including aspheric lens to enhance light output

    International Nuclear Information System (INIS)

    English, G.J.

    1984-01-01

    A photoflash unit employing an optical system or apparatus with improved center beam candle power seconds and zonal lumen seconds from the flash lamp therein, said unit also employing a minimized utilization ratio of lamp-to-package cross-sectional area. Each individual lamp capsule comprises a reflective element, a refractive element (lens), and at least one photoflash lamp (light source). The lens provides for lamp shred magnification so as to fill the cell (capsule) width to thus provide maximum transfer of light to the subject on axis. One embodiment has the light source fused (glued) to the reflector and lens while a second embodiment has an air interface between the source and the optical elements. In both embodiments, the lens is aspheric and substantially covers both the reflector and source

  16. Wide-Spectrum Microscope with a Long Working Distance Aspherical Objective Based on Obscuration Constraint

    Directory of Open Access Journals (Sweden)

    Weibo Wang

    2016-11-01

    Full Text Available We present an approach for an initial configuration design based on obscuration constraint and on-axis Taylor series expansion to realize the design of long working distance microscope (numerical aperture (NA = 0.13 and working distance (WD = 525 mm with a low obscuration aspherical Schwarzschild objective in wide-spectrum imaging (λ = 400–900 nm. Experiments of the testing on the resolution target and inspection on United States Air Force (USAF resolution chart and a line charge-coupled device (CCD (pixel size of 14 μm × 56 μm with different wavelength light sources (λ = 480 nm, 550 nm, 660 nm, 850 nm were implemented to verify the validity of the proposed method.

  17. Measuring large aspherics using a commercially available 3D-coordinate measuring machine

    Science.gov (United States)

    Otto, Wolfgang; Matthes, Axel; Schiehle, Heinz

    2000-07-01

    A CNC-controlled precision measuring machine is a very powerful tool in the optical shop not only to determine the surface figure, but also to qualify the radius of curvature and conic constant of aspherics. We used a commercially available 3D-coordinate measuring machine (CMM, ZEISS UPMC 850 CARAT S-ACC) to measure the shape of the GEMINI 1-m convex secondary mirrors at different lapping and polishing stages. To determine the measuring accuracy we compared the mechanical measurements with the results achieved by means of an interferometrical test setup. The data obtained in an early stage of polishing were evaluated in Zernike polynomials which show a very good agreement. The deviation concerning long wave rotational symmetrical errors was 20 nm rms, whereas the accuracy measuring of mid spatial frequency deviations was limited to about 100 nm rms.

  18. Aspherical nucleosynthesis in a core-collapse supernova with 25 M {sub ☉} standard progenitor

    Energy Technology Data Exchange (ETDEWEB)

    Popov, M. V. [École Normale Supérieure de Lyon, CRAL (UMR CNRS 5574), Université de Lyon 1, 46 allée d' Italie, F-69007 Lyon (France); Filina, A. A.; Baranov, A. A.; Chardonnet, P. [LAPTh, Université de Savoie, 9, Chemin de Bellevue BP 110, F-74941 Annecy-le-Vieux Cedex (France); Chechetkin, V. M. [Keldysh Institute of Applied Mathematics RAS, Miusskaya sq. 4, 125047 Moscow (Russian Federation)

    2014-03-01

    The problem of nucleosynthesis was studied within an aspherical supernova model. The explosive burning was computed in a star of 25 M {sub ☉} initial mass on its final stage of evolution. The chemical composition of a presupernova was taken from realistic evolutionary computations. A piecewise parabolic method on a local stencil was applied to simulate the hydrodynamics of the explosion. The gravity was recomputed by a Poisson solver on a fine grid as the explosion developed. A detailed yield of chemical elements was performed as a post-processing step using the tracer particles method. The produced nuclei formed a layer-like structure enclosing large fragments of nickel and iron-group isotopes that were pushed away from the central region by an explosion along the polar direction. The light nuclei were preferentially moving along the equatorial plane forming a torus-like structure.

  19. The Scales of Gravitational Lensing

    Directory of Open Access Journals (Sweden)

    Francesco De Paolis

    2016-03-01

    Full Text Available After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge of supermassive black holes in the center of ours and nearby galaxies.

  20. Acute Retention of Urine Following Intraocular Surgery | Nwosu ...

    African Journals Online (AJOL)

    Hyperosmolar agents and carbonic anhydrase inhibitors are used to lower the intraocular pressure and thus minimize the chances of vitreous loss during intraocular surgery. However, these agents could precipitate urinary retention. This is a report on two elderly men who had perioperative acute urinary retention following ...

  1. Implantable intraocular pressure monitoring systems: Design considerations

    KAUST Repository

    Arsalan, Muhammad; Ouda, Mahmoud H.; Marnat, Loic; Shamim, Atif; Salama, Khaled N.

    2013-01-01

    Design considerations and limitations of implantable Intraocular Pressure Monitoring (IOPM) systems are presented in this paper. Detailed comparison with the state of the art is performed to highlight the benefits and challenges of the proposed design. The system-on-chip, presented here, is battery free and harvests energy from incoming RF signals. This low-cost design, in standard CMOS process, does not require any external components or bond wires to function. This paper provides useful insights to the designers of implantable wireless sensors in terms of design choices and associated tradeoffs. © 2013 IEEE.

  2. Implantable intraocular pressure monitoring systems: Design considerations

    KAUST Repository

    Arsalan, Muhammad

    2013-12-01

    Design considerations and limitations of implantable Intraocular Pressure Monitoring (IOPM) systems are presented in this paper. Detailed comparison with the state of the art is performed to highlight the benefits and challenges of the proposed design. The system-on-chip, presented here, is battery free and harvests energy from incoming RF signals. This low-cost design, in standard CMOS process, does not require any external components or bond wires to function. This paper provides useful insights to the designers of implantable wireless sensors in terms of design choices and associated tradeoffs. © 2013 IEEE.

  3. Primary intraocular chondrosarcoma in a dog

    Directory of Open Access Journals (Sweden)

    E. Perlmann

    2013-12-01

    Full Text Available A five-year-old male Cocker Spaniel was presented for evaluation of the right eye due to discomfort, abundant purulent discharge and progressive enlargement of the eyeball. The owner revealed that the right eye has appeared to be inflamed and smaller then the left eye for years. Ophthalmic examination revealed corneal perforation, buphthalmia and conjuctival hyperemia. Enucleating was performed due to signs of endophthalmitis and ocular discomfort. Histopathology revealed a multilobulated proliferation of chondrocytes producing hyaline cartilage with occasional pleomorphism and binucleate cells. A diagnosis of primary intraocular chondrosarcoma was done.

  4. Characterization of sand lenses embedded in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K.E.S.; Nilsson, B.

    2012-01-01

    Tills dominate large parts of the superficial sediments on the Northern hemisphere. These glacial diamictons are extremely heterogeneous and riddled with fractures and lenses of sand or gravel. The frequency and geometry of sand lenses within tills are strongly linked to glaciodynamic processes...

  5. Planck 2015 results: XV. Gravitational lensing

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Arnaud, M.

    2016-01-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40σ), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator, we detect lensing at a significance of 5σ. We...

  6. Lenses and Perception: Investigations with Light

    Science.gov (United States)

    Akcay, Hakan

    2005-01-01

    The main goals of these activities are to help students learn how a convex lens can serve as a magnifying lens and how light travels and creates images. These explorations will introduce middle school students to different types of lenses and how they work. Students will observe and describe how lenses bend light that passes through them and how…

  7. BAYESIAN INFERENCE OF CMB GRAVITATIONAL LENSING

    Energy Technology Data Exchange (ETDEWEB)

    Anderes, Ethan [Department of Statistics, University of California, Davis, CA 95616 (United States); Wandelt, Benjamin D.; Lavaux, Guilhem [Sorbonne Universités, UPMC Univ Paris 06 and CNRS, UMR7095, Institut d’Astrophysique de Paris, F-75014, Paris (France)

    2015-08-01

    The Planck satellite, along with several ground-based telescopes, has mapped the cosmic microwave background (CMB) at sufficient resolution and signal-to-noise so as to allow a detection of the subtle distortions due to the gravitational influence of the intervening matter distribution. A natural modeling approach is to write a Bayesian hierarchical model for the lensed CMB in terms of the unlensed CMB and the lensing potential. So far there has been no feasible algorithm for inferring the posterior distribution of the lensing potential from the lensed CMB map. We propose a solution that allows efficient Markov Chain Monte Carlo sampling from the joint posterior of the lensing potential and the unlensed CMB map using the Hamiltonian Monte Carlo technique. The main conceptual step in the solution is a re-parameterization of CMB lensing in terms of the lensed CMB and the “inverse lensing” potential. We demonstrate a fast implementation on simulated data, including noise and a sky cut, that uses a further acceleration based on a very mild approximation of the inverse lensing potential. We find that the resulting Markov Chain has short correlation lengths and excellent convergence properties, making it promising for applications to high-resolution CMB data sets in the future.

  8. Electron beams, lenses, and optics. Volume 1

    International Nuclear Information System (INIS)

    El-Kareh, A.B.; El-Kareh, J.C.J.

    1970-01-01

    This book treats the ideal case where all lenses are assumed to be free from errors. It presents a thorough mathematical analysis of the electrostatic immersion lens, both symmetrical and asymetrical, and covers the einzel lens and the symmetrical magnetic lens in detail. The authors have obtained data on these lenses by means of a digital computer and present them in tabular form

  9. A Case Report of Intraocular Metastasis Treated with Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ok Bae; Byun, Sang Jun; Kim, Kwang Soo; Kim, Jin Hee [Keimyung University School of Medicine, Daegu (Korea, Republic of); Lee, Ho Jun [Daegu Catholic University School of Medicine, Daegu (Korea, Republic of)

    2009-09-15

    Intraocular metastasis is the most common malignancy of the eye. The frequency of intraocular metastasis in all the patients dying of cancer is about 12% and ocular metastases will be detected more frequently in the future because the patients with malignant tumor are now living longer. Intraocular metastasis can cause a serious clinical problem such as blindness. The early recognition and treatment of intraocular metastasis are very important clinical oncologic issues to maintain vision and to maximize the quality of life. However, significance of intraocular metastasis is still under-evaluated for practicing oncologists. External beam radiotherapy is a safe, effective palliative treatment in terms of preserving both the vision and the eye globe.

  10. Solutions for care of silicone hydrogel lenses.

    Science.gov (United States)

    Willcox, Mark D P

    2013-01-01

    During wear of contact lenses on a daily wear basis, it is necessary to disinfect the lens overnight before reinserting the lens the next day. The ability of the solutions used for this to disinfect lenses and lens cases is important for safe lens wear. The literature on the disinfecting ability of multipurpose disinfecting solutions (MPDS) commonly used with silicone hydrogel lenses reported during the period 2000 to 2012 is reviewed, as this is the period of time during which these lenses have been commercially available. Particular emphasis is placed on the ability of disinfecting solutions to control colonization of lens cases by microbes and changes in composition and use of the solutions. In addition, the literature is reviewed on ways of minimizing lens case microbial contamination. Maintaining the hygiene of contact lenses and lens cases is important in minimizing various forms of corneal infiltrative events that occur during lens wear. Although lens case contamination is not associated with different lenses, it is determined by use of different MPDS. MPDS that allow more frequent or heavy contamination of cases by Gram-negative bacteria are associated with a higher incidence of corneal infiltrative events. MPDS are now available that contain dual disinfectants. Wiping lens cases with tissues or using lens cases that incorporate silver are associated with reductions in contamination in clinical trials. Similarly, using MPDS to rub and rinse lenses before disinfection may reduce levels of microbes on lenses. The MPDS also contain surfactants that help reduce deposition and denaturation of proteins on lenses. Improvements in MPDS formulations and hygiene practices may help to reduce the incidence of adverse events that are seen during use with silicone hydrogel lenses.

  11. On the retinal toxicity of intraocular glucocorticoids.

    Science.gov (United States)

    Torriglia, Alicia; Valamanesh, Fatemeh; Behar-Cohen, Francine

    2010-12-15

    Corticosteroids are hormones involved in many physiological responses such as stress, immune modulation, protein catabolism and water homeostasis. The subfamily of glucocorticoids is used systemically in the treatment of inflammatory diseases or allergic reactions. In the eye, glucocorticoides are used to treat macular edema, inflammation and neovascularization. The most commonly used glucocorticoid is triamcinolone acetonide (TA). The pharmaceutical formulation of TA is not adapted for intravitreal administration but has been selected by ophthalmologists because its very low intraocular solubility provides sustained effect. Visual benefits of intraocular TA do not clearly correlate with morpho-anatomical improvements, suggesting potential toxicity. We therefore studied, non-common, but deleterious effects of glucocorticoids on the retina. We found that the intravitreal administration of TA is beneficial in the treatment of neovascularization because it triggers cell death of endothelial cells of neovessels by a caspase-independent mechanism. However, this treatment is toxic for the retina because it induces a non-apoptotic, caspase-independent cell death related to paraptosis, mostly in the retinal pigmented epithelium cells and the Müller cells. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. [Contemporary possibilities of intraocular pressure measurement].

    Science.gov (United States)

    Hornová, J; Baxant, A

    2013-10-01

    Authors introduced current possibilities of measuring intraocular pressure (IOP). A list of available methods of monitoring IOP is published; contact measurement method IOP directly on the cornea, but also over upper lid, methodology of minimal contact and non-contact measurement. Following contact methods are described; former measurements of IOP by impression Schiotz tonometer and the current methodology applanation. So far as the gold standard measurement Goldmann applanation tonometer (GAT) is considered, another methodology with applanation measurements are compared: Pascal dynamic contoured tonometer (DCT ), BioResonator - resonant applanation tonometer (ART ), digital applanation tonometer Tonopen and last hit: continuous measurement of IOP by Sensimed Triggerfish. Orientation and rapid assessment is palpation pressure control over the lid and measuring by tonometer Diaton. Rebound tonometer (RBT) iCare belongs to measurements with minimal contact, no need anesthetic drops and fluorescein, therefore a self - home version of IOP measurements (Icare ONE) is developed. Non-contact measurement of IOP by different pneumotonometers is popular for screening assessment of IOP. Reichert Ocular Response Analyzer (ORA) is a non-contact applanation IOP measurement and reveals additional properties of the cornea. In the discussion of a range methodology is evaluated, the experience of other authors and their own experience is compared. For monitoring of patients is necessary to select the most suitable methodology, measure repeatedly and accurately to allow long-term monitoring of intraocular pressure.

  13. Sutureless Intrascleral Fixated Intraocular Lens Implantation.

    Science.gov (United States)

    Karadag, Remzi; Celik, Haci Ugur; Bayramlar, Huseyin; Rapuano, Christopher J

    2016-08-01

    To review sutureless intrascleral intraocular lens (IOL) fixation methods. Review of published literature. Sutureless intrascleral IOL fixation methods are newer and have been developed to eliminate the suture-related complications of sutured scleral fixation methods such as suture-induced inflammation or infection and IOL dislocation or subluxation due to suture degradation or suture breakage. Sutureless intrascleral fixation methods aim for intrascleral haptic fixation to achieve stability of the IOL. Various methods of sutureless scleral fixation have been described. Using a needle, a blade, or a trochar, sclerostomies are created in all techniques for intraocular access. Some surgeons prefer to create scleral tunnels, whereas others use scleral flaps for scleral fixation of haptics. The stability of IOLs is attained by the scar tissue formed around the haptics. Short-term results of these new methods are acceptable; studies including more cases with longer follow-up are needed to determine their long-term success. [J Cataract Refract Surg. 2016;32(9):586-597.]. Copyright 2016, SLACK Incorporated.

  14. Pentacam Scheimpflug quantitative imaging of the crystalline lens and intraocular lens.

    Science.gov (United States)

    Rosales, Patricia; Marcos, Susana

    2009-05-01

    To implement geometrical and optical distortion correction methods for anterior segment Scheimpflug images obtained with a commercially available system (Pentacam, Oculus Optikgeräte GmbH). Ray tracing algorithms were implemented to obtain corrected ocular surface geometry from the original images captured by the Pentacam's CCD camera. As details of the optical layout were not fully provided by the manufacturer, an iterative procedure (based on imaging of calibrated spheres) was developed to estimate the camera lens specifications. The correction procedure was tested on Scheimpflug images of a physical water cell model eye (with polymethylmethacrylate cornea and a commercial IOL of known dimensions) and of a normal human eye previously measured with a corrected optical and geometrical distortion Scheimpflug camera (Topcon SL-45 [Topcon Medical Systems Inc] from the Vrije University, Amsterdam, Holland). Uncorrected Scheimpflug images show flatter surfaces and thinner lenses than in reality. The application of geometrical and optical distortion correction algorithms improves the accuracy of the estimated anterior lens radii of curvature by 30% to 40% and of the estimated posterior lens by 50% to 100%. The average error in the retrieved radii was 0.37 and 0.46 mm for the anterior and posterior lens radii of curvature, respectively, and 0.048 mm for lens thickness. The Pentacam Scheimpflug system can be used to obtain quantitative information on the geometry of the crystalline lens, provided that geometrical and optical distortion correction algorithms are applied, within the accuracy of state-of-the art phakometry and biometry. The techniques could improve with exact knowledge of the technical specifications of the instrument, improved edge detection algorithms, consideration of aspheric and non-rotationally symmetrical surfaces, and introduction of a crystalline gradient index.

  15. Outcomes Associated With Concurrent Iris-Sutured Intraocular Lens Placement and Subluxated Crystalline Lens Extraction.

    Science.gov (United States)

    McClellan, Scott F; Soiberman, Uri; Gehlbach, Peter L; Murakami, Peter N; Stark, Walter J

    2015-08-01

    We have developed a novel surgical technique, to our knowledge, for the management of subluxated crystalline lenses involving preplacement of an iris-sutured posterior chamber intraocular lens (PCIOL) before pars plana vitrectomy and lensectomy. To investigate the outcomes of eyes with subluxated crystalline lenses, predominantly a result of Marfan syndrome (14 eyes [58%]) or trauma (5 eyes [21%]), that underwent pars plana vitrectomy and lensectomy with placement of an iris-sutured PCIOL. We performed a retrospective, noncomparative case series of 24 eyes from 17 consecutive adult patients with surgically treated subluxated crystalline lenses presenting to the Wilmer Eye Institute at Johns Hopkins Hospital from October 6, 2006, through May 1, 2013. The mean (SD) postoperative follow-up was 24.4 (20.5) months for eyes with at least 6 months of follow-up (last date, October 13, 2014). We performed the analysis from January 21, 2014, through January 3, 2015. Improvement in best-corrected visual acuity using an automated Snellen chart and induction of astigmatism for eyes with at least 6 months of follow-up (n = 18) and IOL stability during follow-up for all eyes (n = 24). The mean (SD) age at surgery was 49.4 (10.7 [range, 29-67]) years. We found an improvement in mean (SD [95% CI]) best-corrected visual acuity from 0.66 (0.71 [0.30-1.02]) logMAR preoperatively (Snellen equivalent, approximately 20/90; range, 20/30 to hand motions) to 0.07 (0.11 [95% CI, 0.01-0.12]) logMAR postoperatively (Snellen equivalent, approximately 20/23; range, 20/15 to 20/50). We found little change in astigmatism postoperatively (mean change, -0.1 [95% CI, -0.5 to 0.13] diopters). Postoperative complications included retinal detachment (1 eye [4%]), retained cortical fragment (1 [4%]), cystoid macular edema (2 [8%]), and IOL subluxation (3 [13%]) owing to haptic slippage within 3 months of the procedure. The overall probability of successfully achieving placement of a centered iris

  16. Research on the processing technology of medium-caliber aspheric lens in the optoelectronic integrated test system

    Science.gov (United States)

    Liu, Dan; Yu, Xin-ying; Wang, Wei

    2016-10-01

    In the optoelectronic integrated test system, surface profile and finish of the optical element are put forward higher request. Taking an aspherical quartz glass lens with a diameter of 200mm as example, taking Preston hypothesis as the theoretical basis, analyze the influence of surface quality of various process parameters, including the workpiece and the tool axis spindle speed, wheel type, concentration polishing, polishing mold species, dwell time, polishing pressure and other parameters. Using CNC method for the surface profile and surface quality of the lens were investigated. Taking profilometer measurement results as a guide, by testing and simulation analysis, process parameters were improved constantly in the process of manufacturing. Mid and high frequency error were trimmed and improved so that the surface form gradually converged to the required accuracy. The experimental results show that the final accuracy of the surface is less than 2µm and the surface finish is, which fulfils the accuracy requirement of aspherical focusing lens in optical system.

  17. A normal mode treatment of semi-diurnal body tides on an aspherical, rotating and anelastic Earth

    Science.gov (United States)

    Lau, Harriet C. P.; Yang, Hsin-Ying; Tromp, Jeroen; Mitrovica, Jerry X.; Latychev, Konstantin; Al-Attar, David

    2015-08-01

    Normal mode treatments of the Earth's body tide response were developed in the 1980s to account for the effects of Earth rotation, ellipticity, anelasticity and resonant excitation within the diurnal band. Recent space-geodetic measurements of the Earth's crustal displacement in response to luni-solar tidal forcings have revealed geographical variations that are indicative of aspherical deep mantle structure, thus providing a novel data set for constraining deep mantle elastic and density structure. In light of this, we make use of advances in seismic free oscillation literature to develop a new, generalized normal mode theory for the tidal response within the semi-diurnal and long-period tidal band. Our theory involves a perturbation method that permits an efficient calculation of the impact of aspherical structure on the tidal response. In addition, we introduce a normal mode treatment of anelasticity that is distinct from both earlier work in body tides and the approach adopted in free oscillation seismology. We present several simple numerical applications of the new theory. First, we compute the tidal response of a spherically symmetric, non-rotating, elastic and isotropic Earth model and demonstrate that our predictions match those based on standard Love number theory. Second, we compute perturbations to this response associated with mantle anelasticity and demonstrate that the usual set of seismic modes adopted for this purpose must be augmented by a family of relaxation modes to accurately capture the full effect of anelasticity on the body tide response. Finally, we explore aspherical effects including rotation and we benchmark results from several illustrative case studies of aspherical Earth structure against independent finite-volume numerical calculations of the semi-diurnal body tide response. These tests confirm the accuracy of the normal mode methodology to at least the level of numerical error in the finite-volume predictions. They also demonstrate

  18. Adherence of Pseudomonas aeruginosa to contact lenses

    International Nuclear Information System (INIS)

    Miller, M.J.

    1988-01-01

    The purpose of this research was to examined the interactions of P. aeruginosa with hydrogel contact lenses and other substrata, and characterize adherence to lenses under various physiological and physicochemical conditions. Isolates adhered to polystyrene, glass, and hydrogel lenses. With certain lens types, radiolabeled cells showed decreased adherence with increasing water content of the lenses, however, this correlation with not found for all lenses. Adherence to rigid gas permeable lenses was markedly greater than adherence to hydrogels. Best adherence occurred near pH 7 and at a sodium chloride concentration of 50 mM. Passive adhesion of heat-killed cells to hydrogels was lower than the adherence obtained of viable cells. Adherence to hydrogels was enhanced by mucin, lactoferrin, lysozyme, IgA, bovine serum albumin, and a mixture of these macromolecules. Adherence to coated and uncoated lenses was greater with a daily-wear hydrogel when compared with an extended-wear hydrogel of similar polymer composition. Greater adherence was attributed to a higher concentration of adsorbed macromolecules on the 45% water-content lens in comparison to the 55% water-content lens

  19. Investigations of Galaxy Clusters Using Gravitational Lensing

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, Matthew P. [Northern Illinois Univ., DeKalb, IL (United States)

    2014-08-01

    In this dissertation, we discuss the properties of galaxy clusters that have been determined using strong and weak gravitational lensing. A galaxy cluster is a collection of galaxies that are bound together by the force of gravity, while gravitational lensing is the bending of light by gravity. Strong lensing is the formation of arcs or rings of light surrounding clusters and weak lensing is a change in the apparent shapes of many galaxies. In this work we examine the properties of several samples of galaxy clusters using gravitational lensing. In Chapter 1 we introduce astrophysical theory of galaxy clusters and gravitational lensing. In Chapter 2 we examine evidence from our data that galaxy clusters are more concentrated than cosmology would predict. In Chapter 3 we investigate whether our assumptions about the number of galaxies in our clusters was valid by examining new data. In Chapter 4 we describe a determination of a relationship between mass and number of galaxies in a cluster at higher redshift than has been found before. In Chapter 5 we describe a model of the mass distribution in one of the ten lensing systems discovered by our group at Fermilab. Finally in Chapter 6 we summarize our conclusions.

  20. Pigment dispersion and chronic intraocular pressure elevation after sulcus placement of 3-piece acrylic intraocular lens.

    Science.gov (United States)

    Almond, M Camille; Wu, Michael C; Chen, Philip P

    2009-12-01

    A 55-year-old man had phacoemulsification and implantation of a 3-piece acrylic intraocular lens (IOL) (AcrySof MA60AC) in the right eye. One month postoperatively, the intraocular pressure (IOP) was 48 mm Hg and peripheral transillumination defects were noted in the iris circumferentially, with the IOL optic edge visible as a silhouette. Gonioscopy showed dense pigmentation of the trabecular meshwork in the right eye, but in the left eye, only mild trabecular meshwork pigment was seen, along with a concave peripheral iris insertion. At 21 months, the right eye required 3 medications for IOP control. While pigment dispersion has been widely reported after placement of 1-piece acrylic IOLs in the ciliary sulcus, we conclude that in susceptible individuals with a concave peripheral iris insertion, pigment dispersion can occur with sulcus placement of a 3-piece acrylic model despite its thinner optic and angulated haptics.

  1. Aspheric photorefractive keratectomy for myopia and myopic astigmatism with the SCHWIND AMARIS laser: 2 years postoperative outcomes

    Science.gov (United States)

    Aslanides, Ioannis M.; Padroni, Sara; Arba-Mosquera, Samuel

    2012-01-01

    Purpose To evaluate mid-term refractive outcomes and higher order aberrations of aspheric PRK for low, moderate and high myopia and myopic astigmatism with the AMARIS excimer laser system (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany). Methods This prospective longitudinal study evaluated 80 eyes of 40 subjects who underwent aspheric PRK. Manifest refractive spherical equivalent (MRSE) of up to −10.00 diopters (D) at the spectacle plane with cylinder up to 3.25 was treated. Refractive outcomes and corneal wavefront data (6 mm pupil to the 7th Zernike order) were evaluated out to 2 years postoperatively. Statistical significance was indicated by P  0.05, both cases). There was a statistical increase in postoperative coma (+0.12 μm) and spherical aberration (+0.14 μm) compared to preoperatively (P < 0.001, both cases). Conclusion Aspheric PRK provides excellent visual and refractive outcomes with induction in individual corneal aberrations but not overall corneal aberrations.

  2. MicroRNA profiling in intraocular medulloepitheliomas.

    Directory of Open Access Journals (Sweden)

    Deepak P Edward

    Full Text Available To study the differential expression of microRNA (miRNA profiles between intraocular medulloepithelioma (ME and normal control tissue (CT.Total RNA was extracted from formalin fixed paraffin embedded (FFPE intraocular ME (n=7 and from age matched ciliary body controls (n=8. The clinical history and phenotype was recorded. MiRNA profiles were determined using the Affymetrix GeneChip miRNA Arrays analyzed using expression console 1.3 software. Validation of significantly dysregulated miRNA was confirmed by quantitative real-time PCR. The web-based DNA Intelligent Analysis (DIANA-miRPath v2.0 was used to perform enrichment analysis of differentially expressed (DE miRNA gene targets in Kyoto Encyclopedia of Genes and Genomes (KEGG pathway.The pathologic evaluation revealed one benign (benign non-teratoid, n=1 and six malignant tumors (malignant teratoid, n=2; malignant non-teratoid, n = 4. A total of 88 miRNAs were upregulated and 43 miRNAs were downregulated significantly (P<0.05 in the tumor specimens. Many of these significantly dysregulated miRNAs were known to play various roles in carcinogenesis and tumor behavior. RT-PCR validated three significantly upregulated miRNAs and three significantly downregulated miRNAs namely miR-217, miR-216a, miR-216b, miR-146a, miR-509-3p and miR-211. Many DE miRNAs that were significant in ME tumors showed dysregulation in retinoblastoma, glioblastoma, and precursor, normal and reactive human cartilage. Enriched pathway analysis suggested a significant association of upregulated miRNAs with 15 pathways involved in prion disease and several types of cancer. The pathways involving significantly downregulated miRNAs included the toll-like receptor (TLR (p<4.36E-16 and Nuclear Factor kappa B (NF-κB signaling pathways (p<9.00E-06.We report significantly dysregulated miRNAs in intraocular ME tumors, which exhibited abnormal profiles in other cancers as well such as retinoblastoma and glioblastoma. Pathway analysis

  3. A study of Brachytherapy for Intraocular Tumor

    International Nuclear Information System (INIS)

    Ji, Kwang Soo; Yoo, Dae Hyun; Lee, Sung Goo; Kim, Jae Hu; Ji, Young Hun

    1996-01-01

    The eye enucleation or external-beam radiation therapy that has been commonly used for the treatment of intraocular tumor have demerits of visual loss and in deficiency of effective tumor dose. Recently, brachytherapy using the plaques containing radioisotope-now treatment method that decrease the demerits of the above mentioned treatment methods and increase the treatment effect-is introduced and performed in the countries, Our purpose of this research is to design suitable shape of plaque for the ophthalmic brachytherapy, and to measure absorbed doses of Ir-192 ophthalmic plaque and thereby calculate the exact radiation dose of tumor and it's adjacent normal tissue. In order to brachytherapy for intraocular tumor, 1. to determine the eye model and selected suitable radioisotope 2. to design the suitable shape of plaque 3. to measure transmission factor and dose distribution for custom made plaques 4. to compare with the these data and results of computer dose calculation models. The result were as followed. 1. Eye model was determined as a 25 mm diameter sphere, Ir-192 was considered the most appropriate as radioisotope for brachytherapy, because of the size, half, energy and availability. 2. Considering the biological response with human tissue and protection of exposed dose, we made the plaques with gold, of which size were 15 mm, 17 mm and 20 mm in diameter, and 1.5 mm in thickness. 3. Transmission factor of plaques are all 0.71 with TLD and film dosimetry at the surface of plaques and 0.45, 0.49 at 1.5 mm distance of surface, respectively. 4. As compared the measured data for the plaque with Ir-192 seeds to results of computer dose calculation model by Gary Luxton et al. and CAP-PLAN (Radiation Treatment Planning System), absorbed doses are within ±10% and distance deviations are within 0.4 mm Maximum error is -11.3% and 0.8 mm, respectively. As a result of it, we can treat the intraocular tumor more effectively by using custom made gold plaque and Ir-192

  4. Lente intra-ocular multifocal difrativa apodizada: resultados Diffractive apodized multifocal intraocular lens: results

    Directory of Open Access Journals (Sweden)

    Virgilio Centurion

    2007-12-01

    Full Text Available OBJETIVO: Mostrar os resultados visuais e refracionais com lente intra-ocular multifocal difrativa apodizada. MÉTODOS: Estudo de 100 olhos de 50 pacientes com catarata, submetidos à facoemulsificação com implante bilateral de lente intra-ocular (LIO multifocal difrativa apodizada. Foi avaliada a acuidade visual binocular sem e com correção para longe e perto, a previsibilidade refracional e a freqüência de uso de óculos. RESULTADOS: A acuidade visual sem correção para longe foi de e " 20/30 em 97,56% dos olhos operados e e" J2 em 100%, sendo que 82% dos pacientes nunca usam óculos e 16% usam de forma esporádica. CONCLUSÃO: A LIO multifocal difrativa apodizada mostrou ser uma opção previsível, reproduzível e segura na correção dos vícios de refração para longe e perto durante a cirurgia da catarata, permitindo elevado índice de independência ao uso de óculos.OBJECTIVE: To show visual and refraction results using multifocal diffractive apodized intraocular lens. METHODS: The study of 100 eyes of 50 patients with cataract, submitted to phacoemulsification with bilateral implant of multifocal diffractive apodized intraocular lens (IOL. Binocular visual acuity was evaluated with and without correction for near and distance, and refraction previsibility and frequency of wearing glasses. RESULTS: Visual acuity without correction for distance was e" 20/30 in 97.56% of eyes operated on and e" J2 in 100%, of these 82% of patients never wear glasses and 16% wear glasses sporadically. CONCLUSION: Multifocal diffractive apodized IOL proved to be a foreseeable option, reproducible and safe in the correction of refraction errors for distance and near during cataract surgery, enabling a high rate of independence from the use of glasses.

  5. Transient anterior subcapsular vacuolar change of the crystalline lens in patients after posterior chamber phakic intraocular lens implantation.

    Science.gov (United States)

    Chung, Jin Kwon; Shin, Jin Hee; Lee, Sung Jin

    2013-10-25

    We present two cases of transient vacuolar changes in the anterior subcapsular space of the crystalline lens in patients after posterior chamber phakic intraocular lens implantation. Implantable collamer lenses (ICL) were implanted in healthy myopic patients. Vacuolar changes developed just after the irrigating procedure through the narrow space between the ICL and the crystalline lens. Slit-lamp examinations and spectral domain optical coherence tomography showed bleb-like lesions in the anterior subcapsular space of one eye in each case, though the lesions gradually improved without visual deterioration. Consequently, the lesions turned into a few anterior subcapsular small faint opacities. Direct irrigation of the narrow space confined by the ICL and the crystalline lens is at risk for the development of vacuolar changes in the crystalline lens. The observed spontaneous reversal indicates that surgeons should not rush to surgical intervention but rather opt for close follow over several weeks.

  6. Nanofocusing refractive X-ray lenses

    Energy Technology Data Exchange (ETDEWEB)

    Boye, Pit

    2010-02-05

    This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where several single lenses are stacked behind each other. The, so-called nanofocusing refractive lenses (NFLs) have a parabolic cylindrical shape with lateral structure sizes in the micrometer range. NFLs are produced by using micro-machining techniques. These micro-fabrication processes and technologies are introduced. The results of the optimization and the final fabrication process for silicon lenses are presented. Subsequently, two experiments that are exemplary for the use of NFLs, are introduced. The rst one employs a high-resolution scanning fluorescence mapping of a geological sample, and the second one is a coherent x-ray diffraction imaging (CXDI) experiment. CXDI is able to reconstruct the illuminated object from recorded coherent diffraction patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wave field along the

  7. Nanofocusing refractive X-ray lenses

    International Nuclear Information System (INIS)

    Boye, Pit

    2010-01-01

    This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where several single lenses are stacked behind each other. The, so-called nanofocusing refractive lenses (NFLs) have a parabolic cylindrical shape with lateral structure sizes in the micrometer range. NFLs are produced by using micro-machining techniques. These micro-fabrication processes and technologies are introduced. The results of the optimization and the final fabrication process for silicon lenses are presented. Subsequently, two experiments that are exemplary for the use of NFLs, are introduced. The rst one employs a high-resolution scanning fluorescence mapping of a geological sample, and the second one is a coherent x-ray diffraction imaging (CXDI) experiment. CXDI is able to reconstruct the illuminated object from recorded coherent diffraction patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wave field along the

  8. Associated depression in pseudophakic patients with intraocular lens with and without chromophore

    Directory of Open Access Journals (Sweden)

    Mendoza-Mendieta ME

    2016-03-01

    Full Text Available María Elena Mendoza-Mendieta, Ana Aurora Lorenzo-Mejía Association to Prevent Blindness in Mexico (APEC, Hospital “Dr Luis Sánchez Bulnes”, Mexico City, Mexico Background: With aging, the crystalline lens turns yellowish, which increases the absorption of wavelengths in the blue electromagnetic spectrum, reducing their photoreception in the retina. Since these wavelengths are the main stimulus in the regulation of the circadian rhythm, progressive reduction in their transmission is associated with chronic sleep disturbances and depression in elderly patients. Cataract extraction improves circadian photoreception at any age. However, lenses that block blue waves have 27% to 38% less melatonin suppression than lenses that block only ultraviolet (UV rays. Purpose: To assess the depression symptoms in subjects who have had bilateral phacoemulsification and intraocular lens (IOL implants, one group with yellow chromophore IOLs and the other group with transparent IOLs were compared. Setting: Association to Prevent Blindness in Mexico (APEC, Hospital “Dr Luis Sánchez Bulnes”. Design: This was an observational, cross-sectional, and single-center study. Materials and methods: Twenty-six subjects between 60 and 80 years of age, with a history of bilateral phacoemulsification and placement of the same type of IOL in both eyes from 4 to 12 months prior to the study, who attended the follow-up visits and agreed to participate in this study, and provided signed informed consent were included in the study. They were asked to answer the short version of the 15-item Geriatric Depression Scale. Results: The average age of the study participants was 72.5±5.94 years. The group without chromophore included 46.1% (n=12 of the patients and the group with chromophore included 53.9% (n=14 of the patients (P=0.088. Conclusion: In the group of patients with IOLs that block the passage of blue light, the depression rate was 21.4%, a rate similar to that

  9. Intraocular Surgery in Kyphosis: An Easier Approach

    Directory of Open Access Journals (Sweden)

    Karanjit S. Kooner

    2013-06-01

    Full Text Available We describe a 49-year-old man with advanced kyphosis and dense cataract, who could only recline to about 40° from the vertical axis despite a maximal reverse Trendelenburg position and pillows under the head, neck, shoulders and knees. With a single corneal retraction suture at 6 o'clock, the eye could be rotated horizontally, which enabled the surgeon to perform a complex cataract surgery despite prior glaucoma shunt, posterior synechiae, a small pupil and the need to stain the capsule. As the eye can be brought into any desired position with a retraction suture, patients with kyphosis or other conditions that prevent them from assuming a supine position can still have safe intraocular procedures. This maneuver reduces the need to tilt patients to an uncomfortable position that may cause pain, increased breathing difficulty and elevated posterior vitreous pressure.

  10. Intraocular pressure measurements after conductive keratoplasty.

    Science.gov (United States)

    Kymionis, George D; Naoumidi, Tatiana L; Aslanides, Ioannis M; Kumar, Vinod; Astyrakakis, Nikolaos I; Tsilimbaris, Miltiadis; Pallikaris, Ioannis G

    2005-01-01

    To determine the possible impact of conductive keratoplasty (CK) on intraocular pressure (IOP) measurements. A prospective, single-center, noncomparative interventional case series was performed. Baseline and postoperative IOPs were measured by Goldmann applanation tonometry in 32 eyes of 18 patients who underwent CK for hyperopia correction. Mean follow-up was 11.9 months (range: 8 to 18 months). After CK, a statistically significant decrease in the measured IOP was observed (before CK: 14.22+/-1.64 vs after CK: 12.66+/-2.21, P<.001). The change in IOP readings postoperatively was not correlated with age, sex, keratometric readings, or attempted correction. Despite the limitations due to the small number of patients enrolled in this study, the applanation tonometer appears to underestimate the true IOP after CK.

  11. Pharmacokinetics and efficacy of intraocular flurbiprofen.

    Science.gov (United States)

    Blazaki, S; Tsika, C; Tzatzarakis, M; Naoumidi, E; Tsatsakis, A; Tsatsanis, C; Tsilimbaris, Miltiadis K

    2017-12-01

    Intravitreal delivery of non-steroidal anti-inflammatory drugs could be an effective way to treat macular edema caused by posterior segment inflammation. In this study, we evaluated the intravitreal bioavailability and anti-inflammatory efficacy of flurbiprofen in rabbit eyes. For pharmacokinetics, 0.1 ml of 7.66 mg/ml flurbiprofen solution was injected intravitreally and vitreous drug levels were analyzed at specific time points using LC-MS technique. For efficacy, 100 ng lipopolysaccharide of E.coli was injected intravitreally in rabbits to induce inflammation. The animals were separated in three groups and received intraocular flurbiprofen, dexamethasone and PBS to serve as control. Complete ocular examination and total cell count in aqueous fluid were determined to evaluate the extent of inflammation. Eyes were then enucleated for histopathology analysis. The efficacy in the uveitis model was determined by clinical signs of inflammation, total leukocyte count and histology findings. No adverse events were observed during pharmacokinetic assessment. No signs of inflammation, hemorrhage or retina detachment were detected. The recovery of flurbiprofen from vitreous samples was 92.6%. The half-life of flurbiprofen was estimated to be 1.92 h with an elimination constant rate (K) of 0.36. Treatment with intraocular injections of flurbiprofen and dexamethasone significantly reduced total leukocyte count in a manner comparable to dexamethasone [reduction of 96.84% (p flurbiprofen injection compared to control eyes. Flurbiprofen is effective in suppressing inflammation in this experimental uveitis model. In our experimental setting, intravitreal flurbiprofen seem to have a therapeutic result comparable to dexamethasone. However, the half-life of the drug remains short, necessitating further research to prolong its presence in the vitreous cavity.

  12. Computational modeling of intraocular gas dynamics

    International Nuclear Information System (INIS)

    Noohi, P; Abdekhodaie, M J; Cheng, Y L

    2015-01-01

    The purpose of this study was to develop a computational model to simulate the dynamics of intraocular gas behavior in pneumatic retinopexy (PR) procedure. The presented model predicted intraocular gas volume at any time and determined the tolerance angle within which a patient can maneuver and still gas completely covers the tear(s). Computational fluid dynamics calculations were conducted to describe PR procedure. The geometrical model was constructed based on the rabbit and human eye dimensions. SF_6 in the form of pure and diluted with air was considered as the injected gas. The presented results indicated that the composition of the injected gas affected the gas absorption rate and gas volume. After injection of pure SF_6, the bubble expanded to 2.3 times of its initial volume during the first 23 h, but when diluted SF_6 was used, no significant expansion was observed. Also, head positioning for the treatment of retinal tear influenced the rate of gas absorption. Moreover, the determined tolerance angle depended on the bubble and tear size. More bubble expansion and smaller retinal tear caused greater tolerance angle. For example, after 23 h, for the tear size of 2 mm the tolerance angle of using pure SF_6 is 1.4 times more than that of using diluted SF_6 with 80% air. Composition of the injected gas and conditions of the tear in PR may dramatically affect the gas absorption rate and gas volume. Quantifying these effects helps to predict the tolerance angle and improve treatment efficiency. (paper)

  13. Intraocular Lens Calcification; a Clinicopathologic Report

    Directory of Open Access Journals (Sweden)

    Mozhgan Rezaei-Kanavi

    2009-04-01

    Full Text Available

    PURPOSE: To describe the clinical and pathological features of a case of hydrogel intraocular lens (IOL calcification. CASE REPORT: A 48-year-old man underwent explantation of a single-piece hydrophilic acrylic intraocular lens in his left eye because of decreased visual acuity and milky white opalescence of the IOL. The opacified lens was exchanged uneventfully with a hydrophobic acrylic IOL. Gross examination of the explanted IOL disclosed opacification of the optic and haptics. Full-thickness sections of the lens optic were stained with hematoxylin and eosin (H&E, von Kossa and Gram Tworts'. Microscopic examination of the sections revealed fine and diffuse basophilic granular deposits of variable size within the lens optic parallel to the lens curvature but separated from the surface by a moderately clear zone. The deposits were of high calcium content as evident by dark brown staining with von Kossa. Gram Tworts' staining disclosed no microorganisms. CONCLUSION: This report further contributes to the existing literature on hydrogel IOL calcification.

  14. Nanofocusing Parabolic Refractive X-Ray Lenses

    International Nuclear Information System (INIS)

    Schroer, C.G.; Kuhlmann, M.; Hunger, U.T.; Guenzler, T.F.; Kurapova, O.; Feste, S.; Lengeler, B.; Drakopoulos, M.; Somogyi, A.; Simionovici, A. S.; Snigirev, A.; Snigireva, I.

    2004-01-01

    Parabolic refractive x-ray lenses with short focal distance can generate intensive hard x-ray microbeams with lateral extensions in the 100nm range even at short distance from a synchrotron radiation source. We have fabricated planar parabolic lenses made of silicon that have a focal distance in the range of a few millimeters at hard x-ray energies. In a crossed geometry, two lenses were used to generate a microbeam with a lateral size of 330nm by 110nm at 25keV in a distance of 41.8m from the synchrotron radiation source. First microdiffraction and fluorescence microtomography experiments were carried out with these lenses. Using diamond as lens material, microbeams with lateral size down to 20nm and below are conceivable in the energy range from 10 to 100keV

  15. Anterior haptic flexing and in-the-bag subluxation of an accommodating intraocular lens due to excessive capsular bag contraction.

    Science.gov (United States)

    Kramer, Gregory D; Werner, Liliana; Neuhann, Tobias; Tetz, Manfred; Mamalis, Nick

    2015-09-01

    We describe the case of a patient who had cataract surgery with implantation of the hydrophilic acrylic Tetraflex accommodating intraocular lens (IOL), with subsequent development of capsulorhexis phimosis and in-the-bag IOL subluxation. Contraction of the capsular bag secondary to fibrosis resulted in significant anterior flexing of the lens haptic component. Explantation of the IOL-capsular bag complex was required 7 years after implantation. Histopathologic analysis demonstrated multiple areas of thick anterior subcapsular fibrosis. Pseudoexfoliative material was present throughout the surface of the lens capsule. Intraocular lenses manufactured from hydrophilic acrylic material are highly flexible and may be more susceptible to capsule contraction, even in the absence of predisposing ocular and systemic conditions. This case highlights the importance of developing guidelines regarding patient screening and selection for the appropriate use of accommodating and other highly flexible IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  16. Production of {sup 44}Ti in neutrino-driven aspherical supernova explosions

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Shin-ichiro [Kumamoto National College of Technology, 2659-2 Suya, Goshi 861-1102 (Japan); Ono, Masaomi; Hashimoto, Masa-aki [Department of Physics, School of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Kotake, Kei [National Astronomical Observatory Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)

    2014-05-02

    We examine the synthesis of {sup 44}Ti in a neutrino-driven aspherical supernova (SN), focusing on reaction rates related to {sup 44}Ti and rotation of a progenitor. We have performed 2D hydrodynamic simulations of SN of a 15M{sub ⊙} progenitor, whose angular velocity is manually set to be a cylindrical distribution and have followed explosive nucleosynthesis in the ejecta. We find that the faster rates of {sup 40}Ca(α,γ){sup 44}Ti and the slower rate of {sup 44}Ti(α,p){sup 47}V lead to more massive ejection of {sup 44}Ti and {sup 56}Ni and larger ratios <{sup 44}Ti/{sup 56}Ni>. Faster rotation also results in more massive ejection of {sup 44}Ti and {sup 56}Ni. Ratios <{sup 44}Ti/{sup 56}Ni> are however independent from rotation. Large masses of {sup 44}Ti and large ratios observed in SN 1987A and Cas A (> 1O{sup −4}M{sub ⊙} and 1-2 respectively) are not realized in all the models.

  17. Revised Unfilling Procedure for Solid Lithium Lenses

    International Nuclear Information System (INIS)

    Leveling, A.

    2003-01-01

    A procedure for unfilling used lithium lenses to has been described in Pbar Note 664. To date, the procedure has been used to disassemble lenses 20, 21, 17, 18, and 16. As a result of this work, some parts of the original procedure were found to be time consuming and ineffective. Modifications to the original procedure have been made to streamline the process and are discussed in this note. The revised procedure is included in this note.

  18. Microbial adherence to cosmetic contact lenses.

    Science.gov (United States)

    Chan, Ka Yin; Cho, Pauline; Boost, Maureen

    2014-08-01

    To investigate whether cosmetic contact lenses (CCL) with surface pigments affect microbial adherence. Fifteen brands of CCL were purchased from optical, non-optical retail outlets, and via the Internet. A standardized rub-off test was performed on each CCL (five lenses per brand) to confirm the location of the pigments. The rub-off test comprised gentle rubbing on the surfaces of each CCL with wetted cotton buds for a maximum of 20 rubs per surface. A new set of CCL (five lenses per brand) were incubated in Pseudomonas aeruginosa overnight. Viable counts of adhered bacteria were determined by the number of colony-forming units (CFU) on agar media on each lens. The adherence of P. aeruginosa as well as Staphylococcus aureus and Serratia marcescens to three brands of CCL (A-C) (five lenses per brand) were also compared to their adherences on their clear counterparts. Only two of the 15 brands of CCL tested (brands B and C) had pigments that did not detach with the rub-off test. The remaining 13 brands of CCL all failed the rub-off test and these lenses showed higher P. aeruginosa adherence (8.7 × 10(5)-1.9 × 10(6) CFU/lens). Brands B and C lenses showed at least six times less bacterial adhesion than the other 13 brands. Compared to their clear counterparts, bacterial adherence to brands B and C lenses did not differ significantly, whereas brand A lenses showed significantly higher adherence. Surface pigments on CCL resulted in significantly higher bacterial adherence. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  19. Comments on the Gravitational lensing Magnification

    OpenAIRE

    Takashi, HAMANA; Astronomical Institute, Tohoku University

    1998-01-01

    We rederive a relation between gravitational lensing magnification relative to the standard Friedmann distance and one relative to the Dyer-Roeder distance by investigating the null geodesic deviation equation. We show that the relation comes from a natural consequence of the definition of the lensing magnification matrices and is not based on the averaging of the magnifications, which has conventionally been used to derive it. We therefore conclude that the relation is true for each individu...

  20. Comments on the gravitational lensing magnification

    OpenAIRE

    Hamana, Takashi

    1998-01-01

    We rederive a relation between gravitational lensing magnification relative to the standard Friedmann distance and one relative to the Dyer-Roeder distance by investigating the null geodesic deviation equation. We show that the relation comes from a natural consequence of the definition of the lensing magnification matrices and is not based on the averaging of the magnifications, which has conventionally been used to derive it. We therefore conclude that the relation is true for each individu...

  1. Intraocular Pressure in Pregnant and Non-Pregnant Nigerian Women

    African Journals Online (AJOL)

    Erah

    . ... ocular diseases and these were used as the exclusion ... between groups with student's t-test. ... SD = standard deviation, SEM = standard error of mean, N= .... 38(4):229-34. 26. Qureshi IA. Intraocular pressure and pregnancy. Clin. Med.

  2. Factors influencing bacterial adhesion to contact lenses.

    Science.gov (United States)

    Dutta, Debarun; Cole, Nerida; Willcox, Mark

    2012-01-01

    The process of any contact lens related keratitis generally starts with the adhesion of opportunistic pathogens to contact lens surface. This article focuses on identifying the factors which have been reported to affect bacterial adhesion to contact lenses. Adhesion to lenses differs between various genera/species/strains of bacteria. Pseudomonas aeruginosa, which is the predominant causative organism, adheres in the highest numbers to both hydrogel and silicone hydrogel lenses in vitro. The adhesion of this strain reaches maximum numbers within 1h in most in vitro studies and a biofilm has generally formed within 24 h of cells adhering to the lens surface. Physical and chemical properties of contact lens material affect bacterial adhesion. The water content of hydroxyethylmethacrylate (HEMA)-based lenses and their iconicity affect the ability of bacteria to adhere. The higher hydrophobicity of silicone hydrogel lenses compared to HEMA-based lenses has been implicated in the higher numbers of bacteria that can adhere to their surfaces. Lens wear has different effects on bacterial adhesion, partly due to differences between wearers, responses of bacterial strains and the ability of certain tear film proteins when bound to a lens surface to kill certain types of bacteria.

  3. Predicting gravitational lensing by stellar remnants

    Science.gov (United States)

    Harding, Alexander J.; Stefano, R. Di; Lépine, S.; Urama, J.; Pham, D.; Baker, C.

    2018-03-01

    Gravitational lensing provides a means to measure mass that does not rely on detecting and analysing light from the lens itself. Compact objects are ideal gravitational lenses, because they have relatively large masses and are dim. In this paper, we describe the prospects for predicting lensing events generated by the local population of compact objects, consisting of 250 neutron stars, five black holes, and ≈35 000 white dwarfs. By focusing on a population of nearby compact objects with measured proper motions and known distances from us, we can measure their masses by studying the characteristics of any lensing event they generate. Here, we concentrate on shifts in the position of a background source due to lensing by a foreground compact object. With Hubble Space Telescope, JWST, and Gaia, measurable centroid shifts caused by lensing are relatively frequent occurrences. We find that 30-50 detectable events per decade are expected for white dwarfs. Because relatively few neutron stars and black holes have measured distances and proper motions, it is more difficult to compute realistic rates for them. However, we show that at least one isolated neutron star has likely produced detectable events during the past several decades. This work is particularly relevant to the upcoming data releases by the Gaia mission and also to data that will be collected by JWST. Monitoring predicted microlensing events will not only help to determine the masses of compact objects, but will also potentially discover dim companions to these stellar remnants, including orbiting exoplanets.

  4. Visual outcome with the Oculentis Mplus intraocular lens

    OpenAIRE

    Si-Yuan Liu; Xu Yang

    2017-01-01

    AIM: To evaluate the visual outcome of Oculentis Mplus intraocular lens(IOL).METHODS: Totally 20 eyes in 20 patients received phacoemulsification and Oculentis Mplus intraocular lens implantation were as test group, and 20 eyes(Aspira-aA IOL)were as control group. The following postoperative examinations were performed after operation for 3mo: uncorrected visual acuity of distance and near, refractive results, UBM examination, the rate of wearing spectacles and the complications. RESULTS: At ...

  5. Intraocular osseous metaplasia. A clinico-pathological study

    OpenAIRE

    Vemuganti Geeta; Honavar Santosh; Jalali Subhadra

    2002-01-01

    Purpose: To evaluate the clinico-pathologic features of intraocular osseous metaplasia. Methods: Pathology specimens of enucleated eyes submitted to the ophthalmic pathology service at a tertiary eye-care referral center between January 1995 and June 1999 were studied for intraocular osseous metaplasia. Specific histopathologic features noted in specimens with osseous metaplasia were the presence of retinal detachment, gliosis, retinal pigment epithelial hyperplasia, drusen, epiretinal membra...

  6. Relation between intraocular pressure and size of transverse sinuses

    International Nuclear Information System (INIS)

    Kantarci, Mecit; Onbas, Omer; Alper, Fatih; Okur, Adnan; Dane, Senol; Gumustekin, Kenan; Aslankurt, Murat; Yazici, Ahmet Taylan

    2005-01-01

    There are asymmetries in the sizes of transverse sinus and intraocular pressure. The purpose of this study was to investigate possible relationships between the asymmetry of transverse sinuses in TOF MR venography and intraocular pressures of right and left eyes. In this study, subjects were 63 male and 42 female medical school students, aged 18-21 years (mean±SD; 19.72±0.67 years). Subjects with neurological and ophthalmologic disease, particularly dural sinus thrombosis, myopia, trauma and glaucoma, were excluded the study. Subjects were divided into five groups according to the magnitudes of the right- and left-transverse sinuses in MR venography results. There is a functional relation between intraocular pressures of the right and left eyes and asymmetry of the transverse sinus. If the transverse sinus on one side is larger and its venous drainage is greater, the intraocular pressure of the eye on this side is lower. It can be speculated that the transverse sinus size may be associated with pathogenesis of diseases with increased intraocular pressure such as glaucoma. We aim to determine the relation between the size and drainage of transverse sinuses in TOF MR venography and intraocular pressure in patients with open-angle glaucoma in our next study. (orig.)

  7. Relation between intraocular pressure and size of transverse sinuses

    Energy Technology Data Exchange (ETDEWEB)

    Kantarci, Mecit; Onbas, Omer; Alper, Fatih; Okur, Adnan [Atatuerk University, Department of Radiology, Medical Faculty, Erzurum (Turkey); Dane, Senol; Gumustekin, Kenan [Atatuerk University, Department of Physiology, Medical Faculty, Erzurum (Turkey); Aslankurt, Murat [Atatuerk University, Department of Ophtalmatology, Medical Faculty, Erzurum (Turkey); Yazici, Ahmet Taylan [Beyoglu Goez Egitim ve Arastirma Hastanesi, Istanbul (Turkey)

    2005-01-01

    There are asymmetries in the sizes of transverse sinus and intraocular pressure. The purpose of this study was to investigate possible relationships between the asymmetry of transverse sinuses in TOF MR venography and intraocular pressures of right and left eyes. In this study, subjects were 63 male and 42 female medical school students, aged 18-21 years (mean{+-}SD; 19.72{+-}0.67 years). Subjects with neurological and ophthalmologic disease, particularly dural sinus thrombosis, myopia, trauma and glaucoma, were excluded the study. Subjects were divided into five groups according to the magnitudes of the right- and left-transverse sinuses in MR venography results. There is a functional relation between intraocular pressures of the right and left eyes and asymmetry of the transverse sinus. If the transverse sinus on one side is larger and its venous drainage is greater, the intraocular pressure of the eye on this side is lower. It can be speculated that the transverse sinus size may be associated with pathogenesis of diseases with increased intraocular pressure such as glaucoma. We aim to determine the relation between the size and drainage of transverse sinuses in TOF MR venography and intraocular pressure in patients with open-angle glaucoma in our next study. (orig.)

  8. 25G compared with 20G vitrectomy under Resight non-contact wide-angle lenses for Terson syndrome.

    Science.gov (United States)

    Mao, Xinbang; You, Zhipeng

    2017-08-01

    The aim of the present study was to compare the effectiveness of 25G vitrectomy to standard 20G vitrectomy for treatment of Terson syndrome under Resight non-contact wide-angle lenses. This was a case-control study of 20 patients with Terson syndrome (study group) that underwent 25G vitrectomy under Resight non-contact wide-angle lenses, with those of 20 matched patients that underwent 20G vitrectomy (control group). Medical records were reviewed from between July 2011 and October 2013. Data included results of the Early Treatment Diabetic Retinopathy Study examination, ophthalmology B-scan ultrasonography and fundus photography. The mean age, follow-up time, the preoperative visual acuity of LogMAR and the preoperative intraocular pressure (IOP) were all comparable in the two groups (all P>0.05). There were statistically significant differences in postoperative visual acuity of LogMAR compared with preoperative visual acuity (Pcontact wide-angle lenses can achieve a significantly shorter operative time and lower post-operative IOP compared with 20G Vitrectomy.

  9. Adhesion of Pseudomonas aeruginosa to orthokeratology and alignment lenses.

    Science.gov (United States)

    Choo, Jennifer D; Holden, Brien A; Papas, Eric B; Willcox, Mark D P

    2009-02-01

    To determine whether contact lenses designed for orthokeratology (OK) are colonized by greater numbers of bacteria compared with standard (alignment fitted) design rigid gas permeable lenses before and after lens wear. Eighteen 1-year-old cats were randomly fitted with an OK lens in one eye and an alignment fitted (AF) lens in the other eye. Both lenses were made in the same diameter and central thickness and of the same material. Two separate wearing periods of 2 weeks and 6 weeks were used. After each wearing period, lenses were soaked in Pseudomonas aeruginosa (6294 or 6206) for 10 min. The lenses were then reinserted onto their respective corneas for a wearing period of 16 hours after which lenses were collected and remaining adhered bacteria quantified. Unworn control lenses were also soaked and bacteria enumerated for comparison. There were no significant differences in the number of bacteria adherent to unworn AF and OK lenses. Analysis of lenses after wear showed OK lenses retained significantly higher numbers of viable bacteria than AF lenses in all studies. OK lenses retain more bacteria than AF rigid gas permeable lenses after bacteria-loaded overnight lens wear. This may increase the risk for an infection in OK patients should suitable conditions be present. Specific education on the cleaning of OK lenses is essential.

  10. Ocular surface displacement with and without contact lenses during non-contact tonometry.

    Directory of Open Access Journals (Sweden)

    Ulfah Rimayanti

    Full Text Available PURPOSE: To evaluate the displacement of the central ocular surface during non-contact tonometry with and without soft contact lenses and determine the factors associated with the displacement of the central ocular surface and intraocular pressure (IOP reading changes caused by wearing soft contact lenses (CLs. METHODS: One eye each in 21 subjects was studied. The cornea was photographed using a high-speed camera at 5,000 frames/sec during non-contact tonometry without contact lenses (NCL, with -5.0 diopters (D, -0.5 D and +5.0 D CL. The displacement of the ocular surface and the factors affecting displacement at the IOP reading and maximum displacement time were investigated. RESULTS: The IOP readings while wearing +5 D CL were significantly higher than those obtained while wearing -5 D CL. The ocular surface displacement between +5 D CL and other groups were significantly different. A significant positive correlation was found between the ocular surface displacement of subjects at the IOP reading time and the IOP obtained with the non-contact tonometer. A significant negative correlation was found between the ocular surface curvature and the IOP obtained using the non-contact tonometer. The radius of curvature of the ocular surface affected the displacement during the IOP reading and maximum displacement time. CONCLUSIONS: Our results indicate that soft contact lens use changes the ocular surface behavior and IOP readings during non-contact tonometry. The radius of curvature of the eye affects the ocular surface displacement and IOP readings in this situation.

  11. Ocular surface displacement with and without contact lenses during non-contact tonometry.

    Science.gov (United States)

    Rimayanti, Ulfah; Kiuchi, Yoshiaki; Uemura, Shohei; Takenaka, Joji; Mochizuki, Hideki; Kaneko, Makoto

    2014-01-01

    To evaluate the displacement of the central ocular surface during non-contact tonometry with and without soft contact lenses and determine the factors associated with the displacement of the central ocular surface and intraocular pressure (IOP) reading changes caused by wearing soft contact lenses (CLs). One eye each in 21 subjects was studied. The cornea was photographed using a high-speed camera at 5,000 frames/sec during non-contact tonometry without contact lenses (NCL), with -5.0 diopters (D), -0.5 D and +5.0 D CL. The displacement of the ocular surface and the factors affecting displacement at the IOP reading and maximum displacement time were investigated. The IOP readings while wearing +5 D CL were significantly higher than those obtained while wearing -5 D CL. The ocular surface displacement between +5 D CL and other groups were significantly different. A significant positive correlation was found between the ocular surface displacement of subjects at the IOP reading time and the IOP obtained with the non-contact tonometer. A significant negative correlation was found between the ocular surface curvature and the IOP obtained using the non-contact tonometer. The radius of curvature of the ocular surface affected the displacement during the IOP reading and maximum displacement time. Our results indicate that soft contact lens use changes the ocular surface behavior and IOP readings during non-contact tonometry. The radius of curvature of the eye affects the ocular surface displacement and IOP readings in this situation.

  12. Precision cosmology with weak gravitational lensing

    Science.gov (United States)

    Hearin, Andrew P.

    In recent years, cosmological science has developed a highly predictive model for the universe on large scales that is in quantitative agreement with a wide range of astronomical observations. While the number and diversity of successes of this model provide great confidence that our general picture of cosmology is correct, numerous puzzles remain. In this dissertation, I analyze the potential of planned and near future galaxy surveys to provide new understanding of several unanswered questions in cosmology, and address some of the leading challenges to this observational program. In particular, I study an emerging technique called cosmic shear, the weak gravitational lensing produced by large scale structure. I focus on developing strategies to optimally use the cosmic shear signal observed in galaxy imaging surveys to uncover the physics of dark energy and the early universe. In chapter 1 I give an overview of a few unsolved mysteries in cosmology and I motivate weak lensing as a cosmological probe. I discuss the use of weak lensing as a test of general relativity in chapter 2 and assess the threat to such tests presented by our uncertainty in the physics of galaxy formation. Interpreting the cosmic shear signal requires knowledge of the redshift distribution of the lensed galaxies. This redshift distribution will be significantly uncertain since it must be determined photometrically. In chapter 3 I investigate the influence of photometric redshift errors on our ability to constrain dark energy models with weak lensing. The ability to study dark energy with cosmic shear is also limited by the imprecision in our understanding of the physics of gravitational collapse. In chapter 4 I present the stringent calibration requirements on this source of uncertainty. I study the potential of weak lensing to resolve a debate over a long-standing anomaly in CMB measurements in chapter 5. Finally, in chapter 6 I summarize my findings and conclude with a brief discussion of my

  13. [Influence of different multifocal intraocular lens concepts on retinal stray light parameters].

    Science.gov (United States)

    Ehmer, A; Rabsilber, T M; Mannsfeld, A; Sanchez, M J; Holzer, M P; Auffarth, G U

    2011-10-01

    Multifocal intraocular lenses (MIOL) are known to induce various photic phenomena depending on the optical principle. The aim of this study was to investigate the correlation between stray light measurements performed with the C-Quant (Oculus, Germany) and the results of a subjective patient questionnaire. In this study three different MIOLs were compared: AMO ReZoom (refractive design, n=10), AMO ZM900 (diffractive design, n=10) and Oculentis Mplus (near segment design, n=10). Cataract and refractive patients were enrolled in the study. Functional results were evaluated at least 3 months postoperatively followed by stray light measurements and a subjective questionnaire. Surgery was performed for all patients without complications. The three groups were matched for age, IOL power and corrected distance visual acuity (CDVA). Significantly different stray light (median) values log(s) were found (Kruskal-Wallis test, p<0.05): 1.12 log (refractive), 1.13 log (segment) and 1.28 log (diffractive). The subjective questionnaire did not show differences in glare perception but refractive MIOL patients noticed more halos surrounding light sources than the diffractive and segment MIOL patients. Stray light and subjective photopic phenomena do not show any basic correlation. Measurements in patients with refractive MIOLs showed less stray light than near segment or diffractive MIOLs. However, refractive MIOLs induced more halos compared to the other groups analyzed.

  14. Influence of Near-Segment Positioning in a Rotationally Asymmetric Multifocal Intraocular Lens.

    Science.gov (United States)

    Song, In Seok; Yoon, Sam Young; Kim, Jae Yong; Kim, Myoung Joon; Tchah, Hungwon

    2016-04-01

    To compare visual performance and higher order aberrations (HOAs) based on the position of the near segment in eyes with rotationally asymmetric multifocal intraocular lenses (IOLs). Asymmetric multifocal IOLs (Lentis Mplus LS-313; Oculentis Optikgeräte GmbH, Wetzlar, Germany) were implanted with the near segment positioned either inferiorly, superiorly, or temporally. Uncorrected distance (UDVA), intermediate (UIVA), and near (UNVA) visual acuity, corrected distance visual acuity (CDVA), and distance-corrected intermediate (DCIVA) and near (DCNVA) visual acuity, contrast sensitivity, HOAs, and subjective symptom questionnaires were compared at 1 month postoperatively. Forty-five eyes from 45 patients were evaluated (n = 25, 9, and 11 eyes in the inferior, superior, and temporal groups, respectively). No significant differences in UDVA, UIVA, UNVA, CDVA, DCIVA, or DCNVA were found between the three groups (P > .05). The temporal group showed the best results in UDVA, CDVA, and DCNVA, but the inferior group showed the best results in DCIVA and UNVA and the superior group showed the best results in UIVA. Contrast sensitivity and the subjective symptom questionnaire also did not demonstrate any significant differences (P > .05). Total HOA and spherical aberration did not demonstrate any statistically significant differences (P > .05), but vertical coma and horizontal coma demonstrated significant differences based on near segment position (P < .001). The position of the near segment in eyes with rotationally asymmetric multifocal IOLs demonstrates no significant effect on visual performance. Copyright 2016, SLACK Incorporated.

  15. Treatment of dystrophic calcification on a silicone intraocular lens with pars plana vitrectomy

    Directory of Open Access Journals (Sweden)

    Mehta N

    2014-07-01

    Full Text Available Nitish Mehta,1 Roger A Goldberg,2 Chirag P Shah21University of Massachusetts Medical School, Worcester, MA, USA; 2Department of Retina, Ophthalmic Consultants of Boston, Boston, Massachusetts, USAPurpose: Dense, vision-obscuring calcification on the posterior aspect of silicone intraocular lenses (IOLs is often not amenable to neodymium:yttrium-aluminum-garnet capsulotomy, and, in prior reports, has required IOL exchange. We report the successful removal of dense calcium deposition on the posterior surface of a three-piece silicone lens using pars plana vitrectomy (PPV.Materials and methods: A 23-gauge PPV was performed using the Stellaris® vitrectomy system. A light pipe was used to retroilluminate the IOL, and a dense fibrous tissue setting with a low cut-rate and high aspiration rate was able to clear the visual axis of the dystrophic calcification without damaging the IOL optic.Results: Visual acuity improved from 20/100 to 20/25.Conclusion: Small-gauge PPV may be utilized to remove dense dystrophic calcium deposits on the lens surface in lieu of IOL exchange. Keywords: cataract surgery, technique, Nd:YAG capsulotomy, IOL exchange

  16. Intraocular Telescopic System Design: Optical and Visual Simulation in a Human Eye Model.

    Science.gov (United States)

    Zoulinakis, Georgios; Ferrer-Blasco, Teresa

    2017-01-01

    Purpose. To design an intraocular telescopic system (ITS) for magnifying retinal image and to simulate its optical and visual performance after implantation in a human eye model. Methods. Design and simulation were carried out with a ray-tracing and optical design software. Two different ITS were designed, and their visual performance was simulated using the Liou-Brennan eye model. The difference between the ITS was their lenses' placement in the eye model and their powers. Ray tracing in both centered and decentered situations was carried out for both ITS while visual Strehl ratio (VSOTF) was computed using custom-made MATLAB code. Results. The results show that between 0.4 and 0.8 mm of decentration, the VSOTF does not change much either for far or near target distances. The image projection for these decentrations is in the parafoveal zone, and the quality of the image projected is quite similar. Conclusion. Both systems display similar quality while they differ in size; therefore, the choice between them would need to take into account specific parameters from the patient's eye. Quality does not change too much between 0.4 and 0.8 mm of decentration for either system which gives flexibility to the clinician to adjust decentration to avoid areas of retinal damage.

  17. Foot clearance and variability in mono- and multifocal intraocular lens users during stair navigation.

    Science.gov (United States)

    Renz, Erik; Hackney, Madeleine; Hall, Courtney

    2016-01-01

    Intraocular lenses (IOLs) provide distance and near refraction and are becoming the standard for cataract surgery. Multifocal glasses increase variability of toe clearance in older adults navigating stairs and increase fall risk; however, little is known about the biomechanics of stair navigation in individuals with multifocal IOLs. This study compared clearance while ascending and descending stairs in individuals with monofocal versus multifocal IOLs. Eight participants with multifocal IOLs (4 men, 4 women; mean age = 66.5 yr, standard deviation [SD] = 6.26) and fifteen male participants with monofocal IOLs (mean age = 69.9 yr, SD = 6.9) underwent vision and mobility testing. Motion analysis recorded kinematic and custom software-calculated clearances in three-dimensional space. No significant differences were found between groups on minimum clearance or variability. Clearance differed for ascending versus descending stairs: the first step onto the stair had the greatest toe clearance during ascent, whereas the final step to the floor had the greatest heel clearance during descent. This preliminary study indicates that multifocal IOLs have similar biomechanic characteristics to monofocal IOLs. Given that step characteristics are related to fall risk, we can tentatively speculate that multifocal IOLs may carry no additional fall risk.

  18. Gravitationally Lensed Quasars in Gaia: II. Discovery of 24 Lensed Quasars

    Science.gov (United States)

    Lemon, Cameron A.; Auger, Matthew W.; McMahon, Richard G.; Ostrovski, Fernanda

    2018-04-01

    We report the discovery, spectroscopic confirmation and preliminary characterisation of 24 gravitationally lensed quasars identified using Gaia observations. Candidates were selected in the Pan-STARRS footprint with quasar-like WISE colours or as photometric quasars from SDSS, requiring either multiple detections in Gaia or a single Gaia detection near a morphological galaxy. The Pan-STARRS grizY images were modelled for the most promising candidates and 60 candidate systems were followed up with the William Herschel Telescope. 13 of the lenses were discovered as Gaia multiples and 10 as single Gaia detections near galaxies. We also discover 1 lens identified through a quasar emission line in an SDSS galaxy spectrum. The lenses have median image separation 2.13″ and the source redshifts range from 1.06 to 3.36. 4 systems are quadruply-imaged and 20 are doubly-imaged. Deep CFHT data reveal an Einstein ring in one double system. We also report 12 quasar pairs, 10 of which have components at the same redshift and require further follow-up to rule out the lensing hypothesis. We compare the properties of these lenses and other known lenses recovered by our search method to a complete sample of simulated lenses to show the lenses we are missing are mainly those with small separations and higher source redshifts. The initial Gaia data release only catalogues all images of ˜ 30% of known bright lensed quasars, however the improved completeness of Gaia data release 2 will help find all bright lensed quasars on the sky.

  19. Relative radiosensitivity of rat lenses as a function of age

    International Nuclear Information System (INIS)

    Merriam, G.R. Jr.; Szechter, A.

    1975-01-01

    The effect of age on the development of radiation cataracts in rat lenses has been investigated using the Columbia--Sherman rat as an experiment model. A detailed pattern of age dependence was obtained at several different dose levels. In general at dose levels from 200 to 300 rads the lens changes occurred sooner and progressed faster in the adult lenses than in young lenses. In the dose range from 300 rads to 900 rads opacities developed sooner in the young lenses but progression was faster and severe opacities developed sooner in adult lenses. Above 900 rads opacities developed sooner and progressed faster in the young lenses. (U.S.)

  20. AxiSEM3D: broadband seismic wavefields in 3-D aspherical Earth models

    Science.gov (United States)

    Leng, K.; Nissen-Meyer, T.; Zad, K. H.; van Driel, M.; Al-Attar, D.

    2017-12-01

    Seismology is the primary tool for data-informed inference of Earth structure and dynamics. Simulating seismic wave propagation at a global scale is fundamental to seismology, but remains as one of most challenging problems in scientific computing, because of both the multiscale nature of Earth's interior and the observable frequency band of seismic data. We present a novel numerical method to simulate global seismic wave propagation in realistic 3-D Earth models. Our method, named AxiSEM3D, is a hybrid of spectral element method and pseudospectral method. It reduces the azimuthal dimension of wavefields by means of a global Fourier series parameterization, of which the number of terms can be locally adapted to the inherent azimuthal smoothness of the wavefields. AxiSEM3D allows not only for material heterogeneities, such as velocity, density, anisotropy and attenuation, but also for finite undulations on radial discontinuities, both solid-solid and solid-fluid, and thereby a variety of aspherical Earth features such as ellipticity, topography, variable crustal thickness, and core-mantle boundary topography. Such interface undulations are equivalently interpreted as material perturbations of the contiguous media, based on the "particle relabelling transformation". Efficiency comparisons show that AxiSEM3D can be 1 to 3 orders of magnitude faster than conventional 3-D methods, with the speedup increasing with simulation frequency and decreasing with model complexity, but for all realistic structures the speedup remains at least one order of magnitude. The observable frequency range of global seismic data (up to 1 Hz) has been covered for wavefield modelling upon a 3-D Earth model with reasonable computing resources. We show an application of surface wave modelling within a state-of-the-art global crustal model (Crust1.0), with the synthetics compared to real data. The high-performance C++ code is released at github.com/AxiSEM3D/AxiSEM3D.

  1. Corneal Epithelial Remodeling and Its Effect on Corneal Asphericity after Transepithelial Photorefractive Keratectomy for Myopia

    Directory of Open Access Journals (Sweden)

    Jie Hou

    2016-01-01

    Full Text Available Purpose. To evaluate the changes in epithelial thickness profile following transepithelial photorefractive keratectomy (T-PRK for myopia and to investigate the effect of epithelial remodeling on corneal asphericity. Methods. Forty-four patients (44 right eyes who underwent T-PRK were retrospectively evaluated. Epithelial thickness was measured using spectral-domain optical coherence tomography at different corneal zones (central, 2 mm; paracentral, 2–5 mm; and mid-peripheral, 5-6 mm preoperatively and at 1 week and 1, 3, and 6 months postoperatively. The correlation between the changes in corneal epithelial thickness (ΔCET and postoperative Q-value changes (ΔQ was analyzed 6 months postoperatively. Results. Epithelial thickness at 6 months showed a negative meniscus-like lenticular pattern with less central thickening, which increased progressively toward the mid-periphery (3.69±4.2, 5.19±3.8, and 6.23±3.9 μm at the center, paracenter, and mid-periphery, resp., P<0.01. A significant positive relationship was observed between epithelial thickening and ΔQ 6 months postoperatively (r=0.438, 0.580, and 0.504, resp., P<0.01. Conclusions. Significant epithelial thickening was observed after T-PRK and showed a lenticular change with more thickening mid-peripherally, resulting in increased oblateness postoperatively. Epithelial remodeling may modify the epithelial thickness profile after surface ablation refractive surgery for myopia.

  2. A study of brachytherapy for intraocular tumor

    International Nuclear Information System (INIS)

    Ji, Yung Hoon; Lee, Dong Han; Ko, Kyung Hwan; Lee, Tae Won; Lee, Sung Koo; Choi, Moon Sik

    1994-12-01

    Our purpose of this study is to perform brachytherapy for intraocular tumor. The result were as followed. 1. Eye model was determined as a 25 mm diameter sphere. Ir-192 was considered the most appropriate as radioisotope for brachytherapy, because of the size, half, energy and availability. 2. Considering the biological response with human tissue and protection of exposed dose, we made the plaques with gold, of which size were 15 mm, 17 mm and 20 mm in diameter, and 1.5 mm in thickness. 3. Transmission factor of plaques are all 0.71 with TLD and film dosimetry at the surface of plaques and 0.45, 0.49 at 1.5 mm distance of surface, respectively. 4. As compared the measured data for the plaque with Ir-192 seeds to results of computer dose calculation model by Gary Luxton et al. and CAP-PLAN (Radiation Treatment Planning System), absorbed doses are within ±10% and distance deviations are within 0.4 mm. Maximum error is -11.3% and 0.8 mm, respectively. 7 figs, 2 tabs, 28 refs. (Author)

  3. Heavy Silicone Oil and Intraocular Inflammation

    Directory of Open Access Journals (Sweden)

    Francesco Morescalchi

    2014-01-01

    Full Text Available In the past two decades, many advances have been made in vitrectomy instrumentation, surgical techniques, and the use of different tamponade agents. These agents serve close retinal breaks, confine eventual retinal redetachment, and prevent proliferative vitreoretinopathy (PVR. Long-acting gases and silicone oil are effective internal tamponade agents; however, because their specific gravity is lower than that of the vitreous fluid, they may provide adequate support for the superior retina but lack efficacy for the inferior retina, especially when the fill is subtotal. Thus, a specific role may exist for an internal tamponade agent with a higher specific gravity, such as heavy silicone oils (HSOs, Densiron 68, Oxane HD, HWS 45-300, HWS 46-3000, and HeavySil. Some clinical evidence seems to presume that heavy tamponades are more prone to intraocular inflammation than standard silicone if they remain in the eye for several months. In this review, we discuss the fundamental clinical and biochemical/molecular mechanisms involved in the inflammatory response after the use of heavy tamponade: toxicity due to impurities or instability of the agent, direct toxicity and immunogenicity, oil emulsification, and mechanical injury due to gravity. The physical and chemical properties of various HSOs and their efficacy and safety profiles are also described.

  4. Intraocular lens calculations in atypical eyes

    Directory of Open Access Journals (Sweden)

    Aazim A Siddiqui

    2017-01-01

    Full Text Available Cataract surgery is the most performed surgical procedure in the field of ophthalmology. The process of intraocular lens (IOL calculations is a critical step to achieving successful outcomes. Many IOL formulae exist to guide surgeons through the difficult process of picking the most appropriate lens to achieve a certain target refraction. However, these formulae reach within 0.50 diopters of the target refraction only 75% of the time, leaving 25% of the eyes with a significant refractive surprise. A literature review was performed to investigate all the relevant published material on the history, progress, and recent advancements of IOL calculations. Based on this review, the appropriate history, evolution, progress, limitations, and recent advancements are analyzed and explained. Although the modern IOL formulae and biometric devices perform well for average eyes, they are suboptimal for eyes with atypical biometric parameters and also those that are postrefractive and keratoconic. There has not been a single, perfect formula that can resolve the complexities of this process. Various methods of formula optimization and newer generation of IOL formulae and devices may hold the key to improving outcomes in both typical and atypical eyes. These solutions minimize refractive error by introducing new input parameters and complex mathematical techniques to better estimate postoperative lens position.

  5. [The influence of a new surface treatment of silicone intracoular lenses with fluoralkylsitan on the adherence of endophthalmitic bacteria in vitro

    Science.gov (United States)

    Kienast, A; Menz, D-H; Dresp, J; Klinger, M; Bunse, A; Ohgke, H; Solbach, W; Laqua, H; Kämmerer, R; Hoerauf, H

    2003-10-01

    Dynasilan is a fluoroalkylsilan which is able to bind to surface active molecules of intraocular lenses (IOLs), thereby offering a new option for surface modification of silicone lenses. The purpose of this in vitro study was to investigate the influence of this new surface treatment on the adherence of two typical endophthalmitis-inducing bacteria ( Staphylococcus epidermidis, Propionibacterium acnes). A total of 14 Dynasilan-treated and 14 untreated silicone lenses were incubated at 37 degrees C for 24 h in brain heart infusion broth (10(8) CFU/ml) either with Staphylococcus epidermidis or with Propionibacterium acnes for 1 h. Subsequently, the adherent bacteria were resuspended using ultrasonification at 35 kHz for 3 x 45 s. After a dilution series and incubation at 37 degrees C for 24 h or 3 days the colonies were counted. On untreated IOLs incubated with Staphylococcus epidermidis the average number of bacteria was 3.6 x 10(7)/ml, and on treated IOLs the number of counted colonies was reduced to 1.09 x 10(7)/ml. Incubated with Propionibacterium acnes the average number of adherent bacteria on untreated IOLs was 4.75 x 10(4)/ml and on modified IOLs the number was reduced to 2.94 x 10(4)/ml. Dynasilan surface treatment may reduce the adherence of Staphylococcus epidermidis and Propionibacterium acnes on silicone intraocular lenses. Further studies regarding the stability of this treatment, its biocompatibility and influence on lens epithelial cell adhesion are in progress.

  6. Correlations between the alpha angle and femoral head asphericity: Implications and recommendations for the diagnosis of cam femoroacetabular impingement

    International Nuclear Information System (INIS)

    Harris, Michael D.; Kapron, Ashley L.; Peters, Christopher L.; Anderson, Andrew E.

    2014-01-01

    Objective: To determine the strength of common radiographic and radial CT views for measuring true femoral head asphericity. Patients and methods: In 15 patients with cam femoroacetabular impingement (FAI) and 15 controls, alpha angles were measured by two observers using radial CT (0°, 30°, 60°, 90°) and digitally reconstructed radiographs (DRRs) for the: anterior–posterior (AP), standing frog-leg lateral, 45° Dunn with neutral rotation, 45° Dunn with 40° external rotation, and cross-table lateral views. A DRR validation study was performed. Alpha angles were compared between groups. Maximum deviation from a sphere of each subject was obtained from a previous study. Alpha angles from each view were correlated with maximum deviation. Results: There were no significant differences between alpha angles measured on radiographs and the corresponding DRRs (p = 0.72). Alpha angles were significantly greater in patients for all views (p ≤ 0.002). Alpha angles from the 45° Dunn with 40° external rotation, cross-table lateral, and 60° radial views had the strongest correlations with maximum deviation (r = 0.831; r = 0.823; r = 0.808, respectively). The AP view had the weakest correlation (r = 0.358). Conclusion: DRRs were a validated means to simulate hip radiographs. The 45° Dunn with 40° external rotation, cross-table lateral, and 60° radial views best visualized femoral asphericity. Although commonly used, the AP view did not visualize cam deformities well. Overall, the magnitude of the alpha angle may not be indicative of the size of the deformity. Thus, 3D reconstructions and measurements of asphericity could improve the diagnosis of cam FAI

  7. Plasma lenses for focusing relativistic electron beams

    International Nuclear Information System (INIS)

    Govil, R.; Wheeler, S.; Leemans, W.

    1997-01-01

    The next generation of colliders require tightly focused beams with high luminosity. To focus charged particle beams for such applications, a plasma focusing scheme has been proposed. Plasma lenses can be overdense (plasma density, n p much greater than electron beam density, n b ) or underdense (n p less than 2 n b ). In overdense lenses the space-charge force of the electron beam is canceled by the plasma and the remaining magnetic force causes the electron beam to self-pinch. The focusing gradient is nonlinear, resulting in spherical aberrations. In underdense lenses, the self-forces of the electron beam cancel, allowing the plasma ions to focus the beam. Although for a given beam density, a uniform underdense lens produces smaller focusing gradients than an overdense lens, it produces better beam quality since the focusing is done by plasma ions. The underdense lens can be improved by tapering the density of the plasma for optimal focusing. The underdense lens performance can be enhanced further by producing adiabatic plasma lenses to avoid the Oide limit on spot size due to synchrotron radiation by the electron beam. The plasma lens experiment at the Beam Test Facility (BTF) is designed to study the properties of plasma lenses in both overdense and underdense regimes. In particular, important issues such as electron beam matching, time response of the lens, lens aberrations and shot-to-shot reproducibility are being investigated

  8. Weak lensing in generalized gravity theories

    International Nuclear Information System (INIS)

    Acquaviva, Viviana; Baccigalupi, Carlo; Perrotta, Francesca

    2004-01-01

    We extend the theory of weak gravitational lensing to cosmologies with generalized gravity, described in the Lagrangian by a generic function depending on the Ricci scalar and a nonminimal coupled scalar field. We work out the generalized Poisson equations relating the dynamics of the fluctuating components to the two gauge-invariant scalar gravitational potentials, fixing the contributions from the modified background expansion and fluctuations. We show how the lensing equation gets modified by the cosmic expansion as well as by the presence of anisotropic stress, which is non-null at the linear level both in scalar-tensor gravity and in theories where the gravitational Lagrangian term features a nonminimal dependence on the Ricci scalar. Starting from the geodesic deviation, we derive the generalized expressions for the shear tensor and projected lensing potential, encoding the spacetime variation of the effective gravitational constant and isolating the contribution of the anisotropic stress, which introduces a correction due to the spatial correlation between the gravitational potentials. Finally, we work out the expressions of the lensing convergence power spectrum as well as the correlation between the lensing potential and the integrated Sachs-Wolfe effect affecting cosmic microwave background total intensity and polarization anisotropies. To illustrate phenomenologically the effects, we work out approximate expressions for the quantities above in extended quintessence scenarios where the scalar field coupled to gravity plays the role of the dark energy

  9. Research on fabrication of aspheres at the Center of Optics Technology (University of Applied Science in Aalen); Techical Digest

    Science.gov (United States)

    Boerret, Rainer; Burger, Jochen; Bich, Andreas; Gall, Christoph; Hellmuth, Thomas

    2005-05-01

    The Center of Optics Technology at the University of Applied Science, founded in 2003, is part of the School of Optics and Mechatronics. It completes the existing optical engineering department with a full optical fabrication and metrology chain and serves in parallel as a technology transfer center, to provide area industries with the most up-to-date technology in optical fabrication and engineering. Two examples of research work will be presented. The first example is the optimizing of the grinding process for high precision aspheres, the other is generating and polishing of a freeform optical element which is used as a phase plate.

  10. REVIVAL OF THE STALLED CORE-COLLAPSE SUPERNOVA SHOCK TRIGGERED BY PRECOLLAPSE ASPHERICITY IN THE PROGENITOR STAR

    International Nuclear Information System (INIS)

    Couch, Sean M.; Ott, Christian D.

    2013-01-01

    Multi-dimensional simulations of advanced nuclear burning stages of massive stars suggest that the Si/O layers of presupernova stars harbor large deviations from the spherical symmetry typically assumed for presupernova stellar structure. We carry out three-dimensional core-collapse supernova simulations with and without aspherical velocity perturbations to assess their potential impact on the supernova hydrodynamics in the stalled-shock phase. Our results show that realistic perturbations can qualitatively alter the postbounce evolution, triggering an explosion in a model that fails to explode without them. This finding underlines the need for a multi-dimensional treatment of the presupernova stage of stellar evolution

  11. REVIVAL OF THE STALLED CORE-COLLAPSE SUPERNOVA SHOCK TRIGGERED BY PRECOLLAPSE ASPHERICITY IN THE PROGENITOR STAR

    Energy Technology Data Exchange (ETDEWEB)

    Couch, Sean M. [Flash Center for Computational Science, Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Ott, Christian D., E-mail: smc@flash.uchichago.edu, E-mail: cott@tapir.caltech.edu [TAPIR, Mailcode 350-17, California Institute of Technology, Pasadena, CA 91125 (United States)

    2013-11-20

    Multi-dimensional simulations of advanced nuclear burning stages of massive stars suggest that the Si/O layers of presupernova stars harbor large deviations from the spherical symmetry typically assumed for presupernova stellar structure. We carry out three-dimensional core-collapse supernova simulations with and without aspherical velocity perturbations to assess their potential impact on the supernova hydrodynamics in the stalled-shock phase. Our results show that realistic perturbations can qualitatively alter the postbounce evolution, triggering an explosion in a model that fails to explode without them. This finding underlines the need for a multi-dimensional treatment of the presupernova stage of stellar evolution.

  12. Optical methods for the optimization of system SWaP-C using aspheric components and advanced optical polymers

    Science.gov (United States)

    Zelazny, Amy; Benson, Robert; Deegan, John; Walsh, Ken; Schmidt, W. David; Howe, Russell

    2013-06-01

    We describe the benefits to camera system SWaP-C associated with the use of aspheric molded glasses and optical polymers in the design and manufacture of optical components and elements. Both camera objectives and display eyepieces, typical for night vision man-portable EO/IR systems, are explored. We discuss optical trade-offs, system performance, and cost reductions associated with this approach in both visible and non-visible wavebands, specifically NIR and LWIR. Example optical models are presented, studied, and traded using this approach.

  13. Dynamic correction of the laser beam coordinate in fabrication of large-sized diffractive elements for testing aspherical mirrors

    Science.gov (United States)

    Shimansky, R. V.; Poleshchuk, A. G.; Korolkov, V. P.; Cherkashin, V. V.

    2017-05-01

    This paper presents a method of improving the accuracy of a circular laser system in fabrication of large-diameter diffractive optical elements by means of a polar coordinate system and the results of their use. An algorithm for correcting positioning errors of a circular laser writing system developed at the Institute of Automation and Electrometry, SB RAS, is proposed and tested. Highprecision synthesized holograms fabricated by this method and the results of using these elements for testing the 6.5 m diameter aspheric mirror of the James Webb space telescope (JWST) are described..

  14. The effect of intraocular gas and fluid volumes on intraocular pressure.

    Science.gov (United States)

    Simone, J N; Whitacre, M M

    1990-02-01

    Large increases in the intraocular pressure (IOP) of postoperative gas-containing eyes may require the removal of gas or fluid to reduce the IOP to the normal range. Application of the ideal gas law to Friedenwald's equation provides a mathematical model of the relationship between IOP, intraocular gas and fluid volumes, and the coefficient of scleral rigidity. This mathematic model shows that removal of a given volume of gas or fluid produces an identical decrease in IOP and that the more gas an eye contains, the greater the volume reduction necessary to reduce the pressure. Application of the model shows that the effective coefficient of scleral rigidity is low (mean K, 0.0021) in eyes with elevated IOP that have undergone vitrectomy and retinal cryopexy and very low (mean K, 0.0013) in eyes with elevated IOP that have undergone placement of a scleral buckle and band. By using the appropriate mean coefficient of rigidity, the volume of material to be aspirated to produce a given decrease in IOP can be predicted with clinically useful accuracy.

  15. Stationary nonimaging lenses for solar concentration.

    Science.gov (United States)

    Kotsidas, Panagiotis; Chatzi, Eleni; Modi, Vijay

    2010-09-20

    A novel approach for the design of refractive lenses is presented, where the lens is mounted on a stationary aperture and the Sun is tracked by a moving solar cell. The purpose of this work is to design a quasi-stationary concentrator by replacing the two-axis tracking of the Sun with internal motion of the miniaturized solar cell inside the module. Families of lenses are designed with a variation of the simultaneous multiple surface technique in which the sawtooth genetic algorithm is implemented to optimize the geometric variables of the optic in order to produce high fluxes for a range of incidence angles. Finally, we show examples of the technique for lenses with 60° and 30° acceptance half-angles, with low to medium attainable concentrations.

  16. Gravitational Lensing from a Spacetime Perspective

    Directory of Open Access Journals (Sweden)

    Perlick Volker

    2004-09-01

    Full Text Available The theory of gravitational lensing is reviewed from a spacetime perspective, without quasi-Newtonian approximations. More precisely, the review covers all aspects of gravitational lensing where light propagation is described in terms of lightlike geodesics of a metric of Lorentzian signature. It includes the basic equations and the relevant techniques for calculating the position, the shape, and the brightness of images in an arbitrary general-relativistic spacetime. It also includes general theorems on the classification of caustics, on criteria for multiple imaging, and on the possible number of images. The general results are illustrated with examples of spacetimes where the lensing features can be explicitly calculated, including the Schwarzschild spacetime, the Kerr spacetime, the spacetime of a straight string, plane gravitational waves, and others.

  17. Weak lensing in the Dark Energy Survey

    Science.gov (United States)

    Troxel, Michael

    2016-03-01

    I will present the current status of weak lensing results from the Dark Energy Survey (DES). DES will survey 5000 square degrees in five photometric bands (grizY), and has already provided a competitive weak lensing catalog from Science Verification data covering just 3% of the final survey footprint. I will summarize the status of shear catalog production using observations from the first year of the survey and discuss recent weak lensing science results from DES. Finally, I will report on the outlook for future cosmological analyses in DES including the two-point cosmic shear correlation function and discuss challenges that DES and future surveys will face in achieving a control of systematics that allows us to take full advantage of the available statistical power of our shear catalogs.

  18. Aberration characteristics of immersion lenses for LVSEM

    International Nuclear Information System (INIS)

    Khursheed, Anjam

    2002-01-01

    This paper investigates the on-axis aberration characteristics of various immersion objective lenses for low voltage scanning electron microscopy (LVSEM). A simple aperture lens model is used to generate smooth axial field distributions. The simulation results show that mixed field electric-magnetic immersion lenses are predicted to have between 1.5 and 2 times smaller aberration limited probe diameters than their pure-field counterparts. At a landing energy of 1 keV, mixed field immersion lenses operating at the vacuum electrical field breakdown limit are predicted to have on-axis aberration coefficients between 50 and 60 μm, yielding an ultimate image resolution of below 1 nm. These aberrations lie in the same range as those for LVSEM systems that employ aberration correctors

  19. Nanofocusing parabolic refractive x-ray lenses

    International Nuclear Information System (INIS)

    Schroer, C.G.; Kuhlmann, M.; Hunger, U.T.; Guenzler, T.F.; Kurapova, O.; Feste, S.; Frehse, F.; Lengeler, B.; Drakopoulos, M.; Somogyi, A.; Simionovici, A.S.; Snigirev, A.; Snigireva, I.; Schug, C.; Schroeder, W.H.

    2003-01-01

    Parabolic refractive x-ray lenses with short focal distance can generate intensive hard x-ray microbeams with lateral extensions in the 100 nm range even at a short distance from a synchrotron radiation source. We have fabricated planar parabolic lenses made of silicon that have a focal distance in the range of a few millimeters at hard x-ray energies. In a crossed geometry, two lenses were used to generate a microbeam with a lateral size of 380 nm by 210 nm at 25 keV in a distance of 42 m from the synchrotron radiation source. Using diamond as the lens material, microbeams with a lateral size down to 20 nm and below are conceivable in the energy range from 10 to 100 keV

  20. Solid intraocular xanthogranuloma in three Miniature Schnauzer dogs.

    Science.gov (United States)

    Zarfoss, Mitzi K; Dubielzig, Richard R

    2007-01-01

    Macrophages that contain abundant intracytoplasmic lipid are called 'foam cells'. In four canine globes submitted to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW), foam cells formed a solid intraocular mass. The purpose of this study was to describe the histopathologic findings in these cases. The electronic COPLOW database (1993-2006) was searched for the diagnosis of 'foam cell tumor'. Clinical history, gross pathology and histopathology (5-micron sections, hematoxylin and eosin and Alcian blue periodic acid Schiff) were reviewed in all cases. Cases were included if the globe was grossly filled by a solid mass and if all intraocular structures were effaced by lipid-laden foam cell macrophages admixed with birefringent, Alcian blue-positive crystals oriented in stellate patterns. All three patients (four globes) satisfying the selection criteria were Miniature Schnauzers. In all cases the clinical history included diabetes mellitus, hyperlipidemia and chronic bilateral uveitis that was interpreted to be lens-induced. All globes were enucleated because of glaucoma. The term solid intraocular xanthogranuloma was used to describe these cases because the intraocular contents were effaced by a solid mass of foam cells and birefringent crystals. The cases in this report suggest that diabetic Miniature Schnauzers with hyperlipidemia are at risk for lipid and macrophage-rich uveitis, which may in some cases form a solid inflammatory intraocular mass, precipitate glaucoma, and lead to enucleation.

  1. Soft-contact-lenses-induced complications

    Directory of Open Access Journals (Sweden)

    Suvajac Gordana

    2008-01-01

    Full Text Available Background/Aim. Soft contact lenses occupy significant place in ophthalmology, both in the correction of refraction anomalies and in the treatment of many eye diseases. The number of patients that wear soft contact lenses for the purpose of correcting ametropia is constantly increasing. Due to the increasing number of wearers, the percentage of complications that can lead to serious eye damage and serious vision loss is also increasing. The aim of this study was to point out the most common complications related to soft contact lens use. Methods. In the period from 1995−2004 this prospective study included 510 patients wearing soft contact lenses for correcting ametropia. None of the patients wore contact lenses before and none suffered from any system or local diseases that could affected the development of eventual complications. The study took seven years with the patients who wore conventional lenses and three years with those who wore replacement contact lenses. All the necessary ophthalmologic examinations were done (visual acuity, refractokeratometry, the quantity of tear film, biomicroscopic examination of anterior eye segment. All the complications were filmed by video camera. Results. Of all the patients, 19 had blepharitis, 73 suffered from “dry eye”, 57 had conjunctival hyperemia, 12 had conjunctivitis, 34 had gigantopapillary conjunctivitis (GPC, 93 had punctiform epitheliopathy, 20 had corneal infiltration, one patient had keratitis, 91 had corneal vascularisation, and 95 patients had corneal deposits. Conclusion. Both the type and frequency of complications related to soft contact lens use in our group of patients, proved to be significant. Some of this complications (keratitis can significantly damage vision and lead to loss of vision and sometimes can require operative treatment.

  2. The Mathematical Theory of Multifocal Lenses

    Institute of Scientific and Technical Information of China (English)

    Jacob RUBINSTEIN

    2017-01-01

    This paper presents the fundamental optical concepts of designing multifocal ophthalmic lenses and the mathematical methods associated with them.In particular,it is shown that the design methodology is heavily based on differential geometric ideas such as Willmore surfaces.A key role is played by Hamilton's eikonal functions.It is shown that these functions capture all the information on the local blur and distortion created by the lenses.Along the way,formulas for computing the eikonal functions are derived.Finally,the author lists a few intriguing mathematical problems and novel concepts in optics as future projects.

  3. Achromatic Cooling Channel with Li Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Balbekov, V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2002-04-29

    A linear cooling channel with Li lenses, solenoids, and 201 MHz RF cavities is considered. A special lattice design is used to minimize chromatic aberrations by suppression of several betatron resonances. Transverse emittance of muon beam decreases from 2 mm to 0.5 mm at the channel of about 110 m length. Longitudinal heating is modest, therefore transmission of the channel is rather high: 96% without decay and 90% with decay. Minimal beam emittance achievable by similar channel estimated as about 0.25 mm at surface field of Li lenses 10 T.

  4. Refractive outcomes after multifocal intraocular lens exchange.

    Science.gov (United States)

    Kim, Eric J; Sajjad, Ahmar; Montes de Oca, Ildamaris; Koch, Douglas D; Wang, Li; Weikert, Mitchell P; Al-Mohtaseb, Zaina N

    2017-06-01

    To evaluate the refractive outcomes after multifocal intraocular lens (IOL) exchange. Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. Retrospective case series. Patients had multifocal IOL explantation followed by IOL implantation. Outcome measures included type of IOL, surgical indication, corrected distance visual acuity (CDVA), and refractive prediction error. The study comprised 29 patients (35 eyes). The types of IOLs implanted after multifocal IOL explantation included in-the-bag IOLs (74%), iris-sutured IOLs (6%), sulcus-fixated IOLs with optic capture (9%), sulcus-fixated IOLs without optic capture (9%), and anterior chamber IOLs (3%). The surgical indication for exchange included blurred vision (60%), photic phenomena (57%), photophobia (9%), loss of contrast sensitivity (3%), and multiple complaints (29%). The CDVA was 20/40 or better in 94% of eyes before the exchange and 100% of eyes after the exchange (P = .12). The mean refractive prediction error significantly decreased from 0.22 ± 0.81 diopter (D) before the exchange to -0.09 ± 0.53 D after the exchange (P exchange to 0.23 D after the exchange (P exchange can be performed safely with good visual outcomes using different types of IOLs. A lower refractive prediction error and a higher likelihood of 20/40 or better vision can be achieved with the implantation of the second IOL compared with the original multifocal IOL, regardless of the final IOL position. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  5. High-speed optical signal processing using time lenses

    DEFF Research Database (Denmark)

    Galili, Michael; Hu, Hao; Guan, Pengyu

    2015-01-01

    This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle.......This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle....

  6. Dynamics of Fermat potentials in nonperturbative gravitational lensing

    International Nuclear Information System (INIS)

    Frittelli, Simonetta; Newman, Ezra T.

    2002-01-01

    We present a framework, based on the null-surface formulation of general relativity, for discussing the dynamics of Fermat potentials for gravitational lensing in a generic situation without approximations of any kind. Additionally, we derive two lens equations: one for the case of thick compact lenses and the other one for lensing by gravitational waves. These equations in principle generalize the astrophysical scheme for lensing by removing the thin-lens approximation while retaining the weak fields

  7. Intraocular gnathostomiasis: report of a case and review of literature.

    Science.gov (United States)

    Pillai, Gopal S; Kumar, Anil; Radhakrishnan, Natasha; Maniyelil, Jayasree; Shafi, Tufela; Dinesh, Kavitha R; Karim, Shamsul

    2012-04-01

    Intraocular gnathostomiasis is a rare parasitic infection caused by the third-stage larvae of spiruroid nematode Gnanthostoma spp. seen mostly in tropical and subtropical regions. It is a food-borne zoonosis caused by ingestion of raw or undercooked freshwater fish, amphibians, reptiles, birds, and mammals, all of which are known to harbor advanced third-stage larvae of Gnanthostoma spp. To date, 74 cases of intraocular gnathostomiasis have been reported from 12 different countries. Only four countries have reported more than 10 cases each, and India shares the rare distinction of being one of them, with 14 cases. Surprisingly, not a single case of cutaneous gnanthostomiasis has ever been reported from India. We present one such case of intraocular gnathostomiasis in a 41-year-old male who presented with an actively motile worm attached to the iris, and we review the pertinent literature of all such cases reported from India.

  8. Intraocular manifestations of mycobacterium tuberculosis: A review of the literature

    Directory of Open Access Journals (Sweden)

    Lauren A. Dalvin

    2017-05-01

    Full Text Available Mycobacterium tuberculosis: is most commonly associated with pulmonary infection. However, tuberculosis (TB can also affect the eye. TB can affect nearly any tissue in the eye, and a high index of suspicion is required for accurate diagnosis, as many of the intraocular manifestations of TB can mimic other, more common diseases. Correct diagnosis is critical because systemic anti-tuberculosis treatment may be required, and vision loss or even loss of the affected eye can occur without proper treatment. Thus, it is important for ophthalmologists and infectious disease specialists to work together to accurately diagnose and treat intraocular TB. This article reports the various known presentations of intraocular TB and reviews important elements of diagnosis and treatment. Keywords: Mycobacterium, Tuberculosis, Choroidal granuloma, Retinal vasculitis

  9. Epithelial Downgrowth after Intraocular Surgery Treated with Intracameral 5-Fluorouracil

    Directory of Open Access Journals (Sweden)

    Nina Ni

    2015-01-01

    Full Text Available Purpose. To present the clinical and histopathologic correlation of two cases of epithelial downgrowth (EDG after prior intraocular surgery. Methods. Observational case reports. Results. We present two cases of EDG occurring after intraocular surgery. In both cases, after two anterior chamber injections of 5-fluorouracil (5FU, the area of EDG initially regressed. In Case 1, a limited area of EDG eventually recurred, and penetrating keratoplasty with cryotherapy was curative. In Case 2, subsequent corneal edema required Descemet-stripping automated endothelial keratoplasty, and the patient remained clinically free of EDG without further treatment. Conclusion. Intracameral 5FU may have a role in the treatment of EDG after intraocular surgery, though its precise utilization and impact remain to be defined.

  10. A lab-on-phone instrument with varifocal microscope via a liquid-actuated aspheric lens (LAL)

    Science.gov (United States)

    Fuh, Yiin-Kuen; Lai, Zheng-Hong; Kau, Li-Han; Huang, Hung-Jui

    2017-01-01

    In this paper, we introduce a novel concept of liquid-actuated aspheric lens (LAL) with a built-in aspheric polydimethylsiloxane lens (APL) to enable the design of compact optical systems with varifocal microscopic imaging. The varifocal lens module consists of a sandwiched structures such as 3d printed syringe pump functionally serves as liquid controller. Other key components include two acrylic cylinders, a rigid separator, a APL/membrane composite (APLMC) embedded PDMS membrane. In functional operation, the fluidic controller was driven to control the pressure difference and ALPMC deformation. The focal length can be changed through the pressure difference. This is achieved by the adjustment of volume change of injected liquid such that a widely tunable focal length. The proposed LAL can transform to 3 modes: microscopic mode (APLMC only), convex-concave mode and biconcave mode. It is noticeable that LAL in the operation of microscopic mode is tunable in focus via the actuation of APLMC (focal length is from 4.3 to 2.3 mm and magnification 50X) and can rival the images quality of commercial microscopes. A new lab-on-phone device is economically feasible and functionally versatile to offer a great potential in the point of care applications. PMID:28650971

  11. Minimization of variation in volumetric shrinkage and deflection on injection molding of Bi-aspheric lens using numerical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Bensingh, R. Joseph [Central Institute of Plastics Engineering and Technology, Chennai (India); Boopathy, S. Rajendra [College of Engineering, Anna University, Chennai (India); Jebaraj, C. [Vellore Institutes of Technology, Chennai (India)

    2016-11-15

    The profile of a bi-aspheric lens is such a way that the thickness narrows down from center to periphery (convex). Injection molding of these profiles has high shrinkage in localized areas, which results in internal voids or sink marks when the part gets cool down to room temperature. This paper deals with the influence of injection molding process parameters such as mold surface temperature, melt temperature, injection time, V/P Switch over by percentage volume filled, packing pressure, and packing duration on the volumetric shrinkage and deflection. The optimal molding parameters for minimum variation in volumetric shrinkage and deflection of bi-aspheric lens have been determined with the application of computer numerical simulation integrated with optimization. The real experimental work carried out with optimal molding parameters and found to have a shallow and steep surface profile accuracy of 0.14 and 1.57 mm, 21.38-45.66 and 12.28-26.90 μm, 41.56-157.33 and 41.56-157.33 nm towards Radii of curvatures (RoC), surface roughness (Ra) and waviness of the surface profiles (profile error Pt), respectively.

  12. [Correlation of intraocular pressure variation after visual field examination with 24-hour intraocular pressure variations in primary open-angle glaucoma].

    Science.gov (United States)

    Noro, Takahiko; Nakamoto, Kenji; Sato, Makoto; Yasuda, Noriko; Ito, Yoshinori; Ogawa, Shumpei; Nakano, Tadashi; Tsuneoka, Hiroshi

    2014-10-01

    We retrospectively examined intraocular pressure variations after visual field examination in primary open angle glaucoma (POAG), together with its influencing factors and its association with 24-hour intraocular pressure variations. Subjects were 94 eyes (52 POAG patients) subjected to measurements of 24-hour intraocular pressure and of changes in intraocular pressure after visual field examination using a Humphrey Visual Field Analyzer. Subjects were classified into three groups according to the magnitude of variation (large, intermediate and small), and 24-hour intraocular pressure variations were compared among the three groups. Factors influencing intraocular pressure variations after visual field examination and those associated with the large variation group were investigated. Average intraocular pressure variation after visual field examination was -0.28 ± 1.90 (range - 6.0(-) + 5.0) mmHg. No significant influencing factors were identified. The intraocular pressure at 3 a.m. was significantly higher in the large variation group than other two groups (p field examination. Increases in intraocular pressure during the night might be associated with large intraocular pressure variations after visual field examination.

  13. The asphericity of the metabolic tumour volume in NSCLC: correlation with histopathology and molecular markers

    International Nuclear Information System (INIS)

    Apostolova, Ivayla; Ego, Kilian; Steffen, Ingo G.; Buchert, Ralph; Wertzel, Heinz; Achenbach, H.J.; Riedel, Sandra; Schreiber, Jens; Schultz, Meinald; Furth, Christian; Amthauer, Holger; Derlin, Thorsten; Hofheinz, Frank; Kalinski, Thomas

    2016-01-01

    Asphericity (ASP) is a tumour shape descriptor based on the PET image. It quantitates the deviation from spherical of the shape of the metabolic tumour volume (MTV). In order to identify its biological correlates, we investigated the relationship between ASP and clinically relevant histopathological and molecular signatures in non-small-cell lung cancer (NSCLC). The study included 83 consecutive patients (18 women, aged 66.4 ± 8.9 years) with newly diagnosed NSCLC in whom PET/CT with 18 F-FDG had been performed prior to therapy. Primary tumour resection specimens and core biopsies were used for basic histopathology and determination of the Ki-67 proliferation index. EGFR status, VEGF, p53 and ALK expression were obtained in a subgroup of 44 patients. The FDG PET images of the primary tumours were delineated using an automatic algorithm based on adaptive thresholding taking into account local background. In addition to ASP, SUVmax, MTV and some further descriptors of shape and intratumour heterogeneity were assessed as semiquantitative PET measures. SUVmax, MTV and ASP were associated with pathological T stage (Kruskal-Wallis, p = 0.001, p < 0.0005 and p < 0.0005, respectively) and N stage (p = 0.017, p = 0.003 and p = 0.002, respectively). Only ASP was associated with M stage (p = 0.026). SUVmax, MTV and ASP were correlated with Ki-67 index (Spearman's rho = 0.326/p = 0.003, rho = 0.302/p = 0.006 and rho = 0.271/p = 0.015, respectively). The latter correlations were considerably stronger in adenocarcinomas than in squamous cell carcinomas. ASP, but not SUVmax or MTV, showed a tendency for a significant association with the extent of VEGF expression (p = 0.058). In multivariate Cox regression analysis, ASP (p < 0.0005) and the presence of distant metastases (p = 0.023) were significantly associated with progression-free survival. ASP (p = 0.006), the presence of distant metastases (p = 0.010), and Ki-67 index (p = 0.062) were significantly associated with

  14. Computer numerically controlled (CNC) aspheric shaping with toroidal Wheels (Abstract Only)

    Science.gov (United States)

    Ketelsen, D.; Kittrell, W. C.; Kuhn, W. M.; Parks, R. E.; Lamb, George L.; Baker, Lynn

    1987-01-01

    Contouring with computer numerically controlled (CNC) machines can be accomplished with several different tool geometries and coordinated machine axes. To minimize the number of coordinated axes for nonsymmetric work to three, it is common practice to use a spherically shaped tool such as a ball-end mill. However, to minimize grooving due to the feed and ball radius, it is desirable to use a long ball radius, but there is clearly a practical limit to ball diameter with the spherical tool. We have found that the use of commercially available toroidal wheels permits long effective cutting radii, which in turn improve finish and minimize grooving for a set feed. In addition, toroidal wheels are easier than spherical wheels to center accurately. Cutting parameters are also easier to control because the feed rate past the tool does not change as the slope of the work changes. The drawback to the toroidal wheel is the more complex calculation of the tool path. Of course, once the algorithm is worked out, the tool path is as easily calculated as for a spherical tool. We have performed two experiments with the Large Optical Generator (LOG) that were ideally suited to three-axis contouring--surfaces that have no axis of rotational symmetry. By oscillating the cutting head horizontally or vertically (in addition to the motions required to generate the power of the surface) , and carefully coordinating those motions with table rotation, the mostly astigmatic departure for these surfaces is produced. The first experiment was a pair of reflector molds that together correct the spherical aberration of the Arecibo radio telescope. The larger of these was 5 m in diameter and had a 12 cm departure from the best-fit sphere. The second experiment was the generation of a purely astigmatic surface to demonstrate the feasibility of producing axially symmetric asphe.rics while mounted and rotated about any off-axis point. Measurements of the latter (the first experiment had relatively

  15. The asphericity of the metabolic tumour volume in NSCLC: correlation with histopathology and molecular markers

    Energy Technology Data Exchange (ETDEWEB)

    Apostolova, Ivayla; Ego, Kilian; Steffen, Ingo G. [University Hospital, Otto-von-Guericke University Magdeburg, Clinic of Radiology and Nuclear Medicine, Magdeburg (Germany); Buchert, Ralph [University Medicine Charite, Clinic of Nuclear Medicine, Berlin (Germany); Wertzel, Heinz; Achenbach, H.J. [Lung Clinic Lostau GmbH, Lostau (Germany); Riedel, Sandra; Schreiber, Jens [University Hospital, Otto-von-Guericke University Magdeburg, Clinic of Pneumology, Magdeburg (Germany); Schultz, Meinald [Institute of Pathology Stendal, Stendal (Germany); Furth, Christian; Amthauer, Holger [University Hospital, Otto-von-Guericke University Magdeburg, Clinic of Radiology and Nuclear Medicine, Magdeburg (Germany); University Medicine Charite, Clinic of Nuclear Medicine, Berlin (Germany); Derlin, Thorsten [Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany); Hofheinz, Frank [Helmholtz-Center Dresden-Rossendorf, Dresden (Germany); Kalinski, Thomas [University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Institute for Pathology, Magdeburg (Germany); Institute for Pathology Lademannbogen, Hamburg (Germany)

    2016-12-15

    Asphericity (ASP) is a tumour shape descriptor based on the PET image. It quantitates the deviation from spherical of the shape of the metabolic tumour volume (MTV). In order to identify its biological correlates, we investigated the relationship between ASP and clinically relevant histopathological and molecular signatures in non-small-cell lung cancer (NSCLC). The study included 83 consecutive patients (18 women, aged 66.4 ± 8.9 years) with newly diagnosed NSCLC in whom PET/CT with {sup 18}F-FDG had been performed prior to therapy. Primary tumour resection specimens and core biopsies were used for basic histopathology and determination of the Ki-67 proliferation index. EGFR status, VEGF, p53 and ALK expression were obtained in a subgroup of 44 patients. The FDG PET images of the primary tumours were delineated using an automatic algorithm based on adaptive thresholding taking into account local background. In addition to ASP, SUVmax, MTV and some further descriptors of shape and intratumour heterogeneity were assessed as semiquantitative PET measures. SUVmax, MTV and ASP were associated with pathological T stage (Kruskal-Wallis, p = 0.001, p < 0.0005 and p < 0.0005, respectively) and N stage (p = 0.017, p = 0.003 and p = 0.002, respectively). Only ASP was associated with M stage (p = 0.026). SUVmax, MTV and ASP were correlated with Ki-67 index (Spearman's rho = 0.326/p = 0.003, rho = 0.302/p = 0.006 and rho = 0.271/p = 0.015, respectively). The latter correlations were considerably stronger in adenocarcinomas than in squamous cell carcinomas. ASP, but not SUVmax or MTV, showed a tendency for a significant association with the extent of VEGF expression (p = 0.058). In multivariate Cox regression analysis, ASP (p < 0.0005) and the presence of distant metastases (p = 0.023) were significantly associated with progression-free survival. ASP (p = 0.006), the presence of distant metastases (p = 0.010), and Ki-67 index (p = 0.062) were significantly associated with

  16. Capsulorhexis contraction after cataract surgery: Comparison of sharp anterior edge and modified anterior edge acrylic intraocular lenses

    DEFF Research Database (Denmark)

    Corydon, C.; Lindholt, M.; Knudsen, E.B.

    2007-01-01

    eyes) were included in a prospective randomized study. All had phacoemulsification followed by implantation of an IOL with a modified anterior edge (38 eyes) or a sharp anterior edge (46 eyes). One day (baseline) and 3 months postoperatively, the area of the anterior capsule opening was measured using...... retroillumination photographs. RESULTS: There was a significant reduction in the area of the anterior capsule opening from 1 day to 3 months postoperatively in both groups (Psharp...

  17. Bacillus cereus panophthalmitis associated with intraocular gas bubble.

    Science.gov (United States)

    al-Hemidan, A; Byrne-Rhodes, K A; Tabbara, K F

    1989-01-01

    It has become increasingly apparent that Bacillus cereus can cause a severe and devastating form of endophthalmitis following penetrating trauma by a metallic object. B. cereus is an uncommon aetiological agent in non-clostridial gas-forming infections. The patient studied in this single case report showed evidence of intraocular gas mimicking gas gangrene infection. The physiology of non-clostridial bacteria producing gas from anaerobic metabolic conditions is reviewed. Further intraocular and systemic complications which may be avoided by accurate and early diagnosis and the use of recommended treatment with antibiotics such as clindamycin. Images PMID:2493262

  18. Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

    Science.gov (United States)

    Biernaux, J.; Magain, P.; Hauret, C.

    2017-08-01

    Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system. Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars. Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure

  19. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...

  20. A gravitationally lensed quasar discovered in OGLE

    Science.gov (United States)

    Kostrzewa-Rutkowska, Zuzanna; Kozłowski, Szymon; Lemon, Cameron; Anguita, T.; Greiner, J.; Auger, M. W.; Wyrzykowski, Ł.; Apostolovski, Y.; Bolmer, J.; Udalski, A.; Szymański, M. K.; Soszyński, I.; Poleski, R.; Pietrukowicz, P.; Skowron, J.; Mróz, P.; Ulaczyk, K.; Pawlak, M.

    2018-05-01

    We report the discovery of a new gravitationally lensed quasar (double) from the Optical Gravitational Lensing Experiment (OGLE) identified inside the ˜670deg2 area encompassing the Magellanic Clouds. The source was selected as one of ˜60 `red W1 - W2' mid-infrared objects from WISE and having a significant amount of variability in OGLE for both two (or more) nearby sources. This is the first detection of a gravitational lens, where the discovery is made `the other way around', meaning we first measured the time delay between the two lensed quasar images of -132 Technology Telescope spectra. The spectral energy distribution (SED) fitting with the fixed source redshift provided the estimate of the lensing galaxy redshift of z ≈ 0.9 ± 0.2 (90 per cent CL), while its type is more likely to be elliptical (the SED-inferred and lens-model stellar mass is more likely present in ellipticals) than spiral (preferred redshift by the lens model).

  1. Electron Lenses for the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio [Fermilab; Valishev, Alexander [Fermilab; Bruce, Roderik [CERN; Redaelli, Stefano [CERN; Rossi, Adriana [CERN; Salvachua, Belen [CERN

    2014-07-01

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in RHIC at BNL. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, hollow electron beam collimation was studied as an option to complement the collimation system for the LHC upgrades. This project is moving towards a technical design in 2014, with the goal to build the devices in 2015-2017, after resuming LHC operations and re-assessing needs and requirements at 6.5 TeV. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles.

  2. Weak lensing probes of modified gravity

    International Nuclear Information System (INIS)

    Schmidt, Fabian

    2008-01-01

    We study the effect of modifications to general relativity on large-scale weak lensing observables. In particular, we consider three modified gravity scenarios: f(R) gravity, the Dvali-Gabadadze-Porrati model, and tensor-vector-scalar theory. Weak lensing is sensitive to the growth of structure and the relation between matter and gravitational potentials, both of which will in general be affected by modified gravity. Restricting ourselves to linear scales, we compare the predictions for galaxy-shear and shear-shear correlations of each modified gravity cosmology to those of an effective dark energy cosmology with the same expansion history. In this way, the effects of modified gravity on the growth of perturbations are separated from the expansion history. We also propose a test which isolates the matter-potential relation from the growth factor and matter power spectrum. For all three modified gravity models, the predictions for galaxy and shear correlations will be discernible from those of dark energy with very high significance in future weak lensing surveys. Furthermore, each model predicts a measurably distinct scale dependence and redshift evolution of galaxy and shear correlations, which can be traced back to the physical foundations of each model. We show that the signal-to-noise for detecting signatures of modified gravity is much higher for weak lensing observables as compared to the integrated Sachs-Wolfe effect, measured via the galaxy-cosmic microwave background cross-correlation.

  3. Strong gravitational lensing by Sgr A*

    International Nuclear Information System (INIS)

    Bin-Nun, Amitai Y

    2011-01-01

    In recent years, there has been increasing recognition of the potential to use the galactic center as a probe of general relativity in the strong field. There is almost certainly a black hole at Sgr A* in the galactic center, and this would allow us to have the opportunity to probe dynamics near the exterior of the black hole. In the last decade, there has been theoretical research into extreme gravitational lensing in the galactic center. Unlike in most applications of gravitational lensing, where the bending angle is of the order of, at most, an arc minute, very large bending angles are possible for light that closely approaches a black hole. Photons may even loop multiple times around a black hole before reaching the observer. There have been many proposals to use light's close approach to the black hole as a probe of the black hole metric. Of particular interest are the properties of images formed from the light of S stars orbiting in the galactic center. This paper will review some of the attempts made to study extreme lensing as well as extend the analysis of S star lensing. In particular, we are interested in the effect of a Reissner-Nordstrom like 1/r 2 term in the metric and how this would affect the properties of relativistic images.

  4. Electron beams, lenses, and optics. Volume 2

    International Nuclear Information System (INIS)

    El-Kareh, A.B.; El-Kareh, J.C.J.

    1970-01-01

    This volume presents a systematic coverage of aberrations. It analyzes the geometrical aberrations and treats the spherical and chromatic aberrations in great detail. The coefficients of spherical and chromatic aberration have been computed for a series of electrostatic and magnetic lenses and are listed in table form. The book also covers space charge and its effect on highly focused electron beams

  5. Quantum Spin Lenses in Atomic Arrays

    Directory of Open Access Journals (Sweden)

    A. W. Glaetzle

    2017-09-01

    Full Text Available We propose and discuss quantum spin lenses, where quantum states of delocalized spin excitations in an atomic medium are focused in space in a coherent quantum process down to (essentially single atoms. These can be employed to create controlled interactions in a quantum light-matter interface, where photonic qubits stored in an atomic ensemble are mapped to a quantum register represented by single atoms. We propose Hamiltonians for quantum spin lenses as inhomogeneous spin models on lattices, which can be realized with Rydberg atoms in 1D, 2D, and 3D, and with strings of trapped ions. We discuss both linear and nonlinear quantum spin lenses: in a nonlinear lens, repulsive spin-spin interactions lead to focusing dynamics conditional to the number of spin excitations. This allows the mapping of quantum superpositions of delocalized spin excitations to superpositions of spatial spin patterns, which can be addressed by light fields and manipulated. Finally, we propose multifocal quantum spin lenses as a way to generate and distribute entanglement between distant atoms in an atomic lattice array.

  6. Software for Fermat's Principle and Lenses

    Science.gov (United States)

    Mihas, Pavlos

    2012-01-01

    Fermat's principle is considered as a unifying concept. It is usually presented erroneously as a "least time principle". In this paper we present some software that shows cases of maxima and minima and the application of Fermat's principle to the problem of focusing in lenses. (Contains 12 figures.)

  7. Studying dark matter haloes with weak lensing

    NARCIS (Netherlands)

    Velander, Malin Barbro Margareta

    2012-01-01

    Our Universe is comprised not only of normal matter but also of unknown components: dark matter and dark energy. This Thesis recounts studies of dark matter haloes, using a technique known as weak gravitational lensing, in order to learn more about the nature of these dark components. The haloes

  8. Tear exchange and contact lenses: a review.

    Science.gov (United States)

    Muntz, Alex; Subbaraman, Lakshman N; Sorbara, Luigina; Jones, Lyndon

    2015-01-01

    Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  9. Multiply imaged Transient Events in Cluster Lenses

    Science.gov (United States)

    Narasimha, Delampady

    2018-04-01

    ARIES had a successful gravitational microlens project during 1998-2002. A similar monitor for Transient Events in galaxies at high redshift lensed by rich galaxy-clusters provides a challenging possibility with important cosmological implications. Rich galaxy-clusters at intermediate redshifts are powerful gravitational lenses which produce multiple images, in the shape of giant arcs of 5-20" extent, of distant background galaxies in their field. Weak lens shear of the background galaxy distribution can reliably trace the lens mass profile. Multiple images of supernovae or GRBs in the background galaxies can be recorded in a systematic monitor of the system. An unlensed high redshift supernova might not be observable, but when lensed by a galaxy-cluster, it will stand out because the point event brightens relative to the host. The color profile of a high redshift lensed point event will be much more reliable than an unlensed one due to much less host contamination. An estimate of the time delay enables observation of the full light curve of the subsequent images of the event. ARIES can have outside collaboration for multiband simultaneous lightcurves of other images. The measured time delay and position of images of the transient event provide better cosmological constraints including distance scale of the Universe. The Devasthal telescope can detect one or more events by monitoring half a dozen cluster fields over three years time.

  10. Coatings and Tints of Spectacle Lenses

    Directory of Open Access Journals (Sweden)

    H. Zeki Büyükyıldız

    2012-10-01

    Full Text Available Spectacle lenses are made of mineral or organic (plastic materials. Various coatings and tints are applied to the spectacle lenses according to the characteristic of the lens material, and for the personal needs and cosmetic purpose. The coatings may be classified in seven groups: 1 Anti-reflection coatings, 2 Hard coatings, 3 Clean coat, 4 Mirror coatings, 5 Color tint coating (one of coloring processes, 6 Photochromic coating (one of photochromic processes, and 7 Anti-fog coatings. Anti-reflection coatings reduce unwanted reflections from the lens surfaces and increase light transmission. Hard coatings are applied for preventing the plastic lens surface from scratches and abrasion. Hard coatings are not required for the mineral lenses due to their hardness. Clean coat makes the lens surface smooth and hydrophobic. Thus, it prevents the adherence of dust, tarnish, and dirt particles on the lens surface. Mirror coatings are applied onto the sunglasses for cosmetic purpose. Color tinted and photochromic lenses are used for sun protection and absorption of the harmful UV radiations. Anti-fog coatings make the lens surface hydrophilic and prevent the coalescence of tiny water droplets on the lens surface that reduces light transmission. (Turk J Ophthalmol 2012; 42: 359-69

  11. Teaching the Theory of Real Lenses.

    Science.gov (United States)

    Walther, A.

    1996-01-01

    Presents an approach to the study of real lenses that would not contradict Fermat's principle. Shows how the rudiments of the correct theory can be incorporated into courses to provide students a clearer notion of what they can expect in laboratory situations. (DDR)

  12. Are Disposable and Standard Gonioscopy Lenses Comparable?

    Science.gov (United States)

    Lee, Bonny; Szirth, Bernard C; Fechtner, Robert D; Khouri, Albert S

    2017-04-01

    Gonioscopy is important in the evaluation and treatment of glaucoma. With increased scrutiny of acceptable sterilization processes for health care instruments, disposable gonioscopy lenses have recently been introduced. Single-time use lenses are theorized to decrease infection risk and eliminate the issue of wear and tear seen on standard, reusable lenses. However, patient care would be compromised if the quality of images produced by the disposable lens were inferior to those produced by the reusable lens. The purpose of this study was to compare the quality of images produced by disposable versus standard gonioscopy lenses. A disposable single mirror lens (Sensor Medical Technology) and a standard Volk G-1 gonioscopy lens were used to image 21 volunteers who were prospectively recruited for the study. Images of the inferior and temporal angles of each subject's left eye were acquired using a slit-lamp camera through the disposable and standard gonioscopy lens. In total, 74 images were graded using the Spaeth gonioscopic system and for clarity and quality. Clarity wa