WorldWideScience

Sample records for chamber intraocular lenses

  1. Pseudoexfoliation material on posterior chamber intraocular lenses

    Directory of Open Access Journals (Sweden)

    Rocha-Bastos RA

    2014-08-01

    Full Text Available Ricardo António da Rocha-Bastos,1 Sérgio Estrela Silva,1 Flávio Prézia,1 Fernando Falcão-Reis,1,2 António B Melo11Department of Ophthalmology, Hospital São João, Alameda Prof Hernâni Monteiro, Porto, Portugal; 2Department of Sense Organs, Faculty of Medicine, University of Porto, Alameda Prof Hernâni Monteiro, Porto, PortugalAbstract: The presence of pseudoexfoliation material on the surface of an intraocular lens (IOL is a rare finding. We report a series of seven cases with different patterns of pseudoexfoliation material deposition on the posterior chamber IOLs, recognized 2–20 years after cataract surgery. Six patients had an IOL implanted in the capsular bag and one in the ciliary sulcus. Two patients had undergone posterior capsulotomy. Although the pathophysiological mechanisms and clinical significance of this finding remain unknown, the careful follow-up of pseudophakic patients with known or suspected pseudoexfoliation syndrome is essential to monitor the development or progression of glaucoma, since deposition of pseudoexfoliation material continues even after cataract surgery.Keywords: intraocular lens, glaucoma, exfoliation syndrome, cataract

  2. Pseudoexfoliation material on posterior chamber intraocular lenses

    OpenAIRE

    Rocha-Bastos RA; Silva SE; Prézia F; Falcão-Reis F; Melo AB

    2014-01-01

    Ricardo António da Rocha-Bastos,1 Sérgio Estrela Silva,1 Flávio Prézia,1 Fernando Falcão-Reis,1,2 António B Melo11Department of Ophthalmology, Hospital São João, Alameda Prof Hernâni Monteiro, Porto, Portugal; 2Department of Sense Organs, Faculty of Medicine, University of Porto, Alameda Prof Hernâni Monteiro, Porto, PortugalAbstract: The presence of pseudoexfoliation material on the surface of an intraocular lens (IOL) is a ...

  3. Optimum form of posterior chamber intraocular lenses to minimize aberrational astigmatism.

    Science.gov (United States)

    Takei, K; Hommura, S; Okajima, H

    1995-01-01

    To optically determine the optimum form for a posterior chamber intraocular lens (PC IOL), we calculated the aberrational astigmatism induced by tilt and decentration of the PCIOL using an exact raytracing. First, the position and the radii of curvatures of the IOL were determined to make an emmetropic eye model using a paraxial raytracing. Next, the chief rays originating from the fovea centralis were traced backward through the tilted and/or decentrated PC IOL, the center of the pupil and the cornea, using trigonometric raytracing. Finally, the maximum and minimum aberrational astigmatism were calculated based on the Coddington's Equations for the sagittal and the tangential foci of the ray. All the refractive parameters in Gullstrand's No. 1 schematic eye were adopted. The effect of varying anterior corneal asphericity on the results was also examined. Four forms of polymethylmethacrylate PC IOLs (refractive index: 1.491) were analyzed; a plano-convex IOL with the curved surface facing the cornea, and three bi-convex forms with the ratio of anterior-to-posterior radii of curvatures of 1:4, 1:2 and 1:1, respectively. The 1:4 bi-convex form showed the lowest values for the maximum aberrational astigmatism calculated at every combination of tilt and decentration except 0 degrees tilt and/or 0 mm decentration. The aberrational astigmatism with the 1:4 bi-convex form of PC IOL did not exceed 1.0 D at the maximum tilt and decentration. The variation of anterior corneal asphericity did not influence the results. We conclude that the 1:4 bi-convex form of PC IOL minimizes the postoperative astigmatism induced by tilt and/or decentration of the lens. PMID:8926647

  4. Analytical design of intraocular lenses

    OpenAIRE

    Barbero Briones, Sergio; Marcos Celestino, Susana; Dorronsoro Díaz, Carlos

    2008-01-01

    The invention relates to a method for designing intraocular lenses, comprising: the definition of a pseudoaphakic eye model; the definition of a merit function in multiple dimensions, which analytically connects the quality of the image on the retina to the optical and geometric parameters of the pseudoaphakic eye model; and the algorithm optimisation of the previous merit function using analytical and numerical methods in order to obtain one or more minimum globals which provide the optimal ...

  5. Developments in Accommodating Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Zeki Tunç

    2012-07-01

    Full Text Available Technical progress in cataract surgery has decreased the incidence of severe complications in this type of surgery. The introduction of micro incision cataract surgery (MICS (sub- 2.0 mm incision allow the surgeon to achieve better postoperative control of astigmatism and higherorder aberration (HOAs with minimum induction of both. It is believed that multifocal lenses provide very successful results, however, there are limitations to these. Implantation of accommodating intraocular lenses (IOLs is an option to treat presbyopia. The IOLs work by using the continued functionality of the ciliary muscle after cataract removal. Accommodating IOLs were designed to avoid the optical side effects of multifocal IOLs. Two main design concepts exist. First, axial shift concepts rely on anterior axial movement of one or two optics creating accommodative ability. Second, curvature change designs are designed to provide significant amplitudes of accommodation with little physical displacement. Accommodative IOLs to correct astigmatism and HOAs in the future are needed. (Turk J Ophthalmol 2012; 42: 288-93

  6. Surface Modification of Intraocular Lenses

    Institute of Scientific and Technical Information of China (English)

    Qi Huang; George Pak-Man Cheng; Kin Chiu; Gui-Qin Wang

    2016-01-01

    Objective:This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs).Data Sources:All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect.Study Selection:The articles on the surface modification of IOLs were included,but those on design modification and surface coating were excluded.Results:Technology of surface modification included plasma,ion beam,layer-by-layer self-assembly,ultraviolet radiation,and ozone.The main molecules introduced into IOLs surface were poly (ethylene glycol),polyhedral oligomeric silsesquioxane,2-methacryloyloxyethyl phosphorylcholine,TiO2,heparin,F-heparin,titanium,titanium nitride,vinyl pyrrolidone,and inhibitors of cytokines.The surface modification either resulted in a more hydrophobic lens,a more hydrophilic lens,or a lens with a hydrophilic anterior and hydrophobic posterior surface.Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments.Conclusion:The surface modification is an efficient,convenient,economic and promising method to improve the biocompatibility ofIOLs.

  7. Surface Modification of Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Qi Huang

    2016-01-01

    Full Text Available Objective: This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs. Data Sources: All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect. Study Selection: The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded. Results: Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol, polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO 2 , heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments. Conclusion: The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs.

  8. DESIGN OF THE MULTIORDER INTRAOCULAR LENSES

    Directory of Open Access Journals (Sweden)

    V. G. Kolobrodov

    2015-12-01

    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.

  9. Adherence of Staphylococcus epidermidis to intraocular lenses.

    OpenAIRE

    Griffiths, P G; Elliot, T. S.; McTaggart, L

    1989-01-01

    We have demonstrated, with an in vitro model, that Staphylococcus epidermidis is able to colonise intraocular lenses. Adherent organisms were quantitated by light microscopy, scanning electron microscopy, and viable counting. Bacterial adherence was associated with production of a polysaccharide glycocalyx. Organisms which were attached to the lenses were resistant to apparently bactericidal concentrations of antibiotics, as determined by conventional testing. We speculate on the role of colo...

  10. 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.

  11. File list: DNS.Oth.05.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Oth.05.AllAg.Lenses,_Intraocular mm9 DNase-seq Others Lenses, Intraocular http:...//dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Oth.05.AllAg.Lenses,_Intraocular.bed ...

  12. File list: DNS.Oth.10.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: DNS.Oth.20.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Oth.20.AllAg.Lenses,_Intraocular mm9 DNase-seq Others Lenses, Intraocular http:...//dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Oth.20.AllAg.Lenses,_Intraocular.bed ...

  14. File list: DNS.Oth.50.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Oth.50.AllAg.Lenses,_Intraocular mm9 DNase-seq Others Lenses, Intraocular http:...//dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Oth.50.AllAg.Lenses,_Intraocular.bed ...

  15. Drug-Eluting Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Angel Concheiro

    2011-11-01

    Full Text Available Notable advances in materials science and in surgical techniques make the management of cataract by replacement of the opaque crystalline with an intraocular lens (IOL, one of the most cost-effective interventions in current healthcare. The usefulness and safety of IOLs can be enhanced if they are endowed with the ability to load and to sustain drug release in the implantation site. Drug-eluting IOLs can prevent infections and untoward reactions of eye tissues (which lead to opacification and also can act as drug depots for treatment of several other ocular pathologies. Such a myriad of therapeutic possibilities has prompted the design of drug-IOL combination products. Several approaches are under study, namely combination of the IOL with an insert in a single device, soaking in drug solutions, impregnation using supercritical fluids, coating with drug/polymer layers, and covalent grafting of the drug. The advantages/limitations of each technique are discussed in the present review on selected examples. Although more in vivo data are required, the information already available proves the interest of some approaches in ocular therapeutics.

  16. Evaluating the method increasing of toric intraocular lenses rotational stability

    OpenAIRE

    G. A. Fedjashev

    2015-01-01

    Purpose. To suggest a safe and effective way to improve the rotational stability of the position of toric the intraocular lenses in the capsular bag.Patients and methods.86 patients (97 eyes) with corneal astigmatism undergoing cataract surgery and Acrysof Toric (Alcon, USA) intraocular lens implantation. In 42 patients (47 eyes), the intraocular lens (IOL) were implanted in accordance with the proposed invention.Results. Average rotation angle IOL implanted by traditional technology was 2,2±...

  17. File list: Pol.Oth.50.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  18. File list: InP.Oth.05.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  19. File list: Oth.Oth.50.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  20. File list: Unc.Oth.20.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  1. File list: His.Oth.50.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  2. File list: Pol.Oth.05.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  3. File list: InP.Oth.20.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  4. File list: NoD.Oth.20.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  5. File list: His.Oth.20.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  6. File list: Unc.Oth.50.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  8. File list: InP.Oth.10.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  9. File list: Oth.Oth.10.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  10. File list: NoD.Oth.10.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  11. File list: NoD.Oth.05.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: NoD.Oth.50.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: Pol.Oth.20.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  14. File list: Pol.Oth.10.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Oth.10.AllAg.Lenses,_Intraocular mm9 RNA polymerase Others Lenses, Intraocular ...SRX957689 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Oth.10.AllAg.Lenses,_Intraocular.bed ...

  15. File list: Oth.Oth.20.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Oth.20.AllAg.Lenses,_Intraocular mm9 TFs and others Others Lenses, Intraocular ...SRX957680 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Oth.20.AllAg.Lenses,_Intraocular.bed ...

  16. File list: Oth.Oth.05.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Oth.05.AllAg.Lenses,_Intraocular mm9 TFs and others Others Lenses, Intraocular ...SRX957680 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Oth.05.AllAg.Lenses,_Intraocular.bed ...

  17. File list: His.Oth.10.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Oth.10.AllAg.Lenses,_Intraocular mm9 Histone Others Lenses, Intraocular SRX9576...85,SRX957687,SRX957695,SRX957683 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Oth.10.AllAg.Lenses,_Intraocular.bed ...

  18. The dangers of metal-loop intraocular lenses.

    Science.gov (United States)

    Shepard, D D

    1977-10-01

    The author implanted 500 intraocular lenses (IOLs) during intracapsular surgery. Data from the 60 lenses with metal posterior loops showed a markedly high incidence of complication compared to plastic loops: twice as many overall complications, three times the cystoid mascular edema, three times the rate for subsequent corrective surgical procedures, and 30 times more IOLs had to be removed. IOL manufacturers are advised to abandon metal loops for intracapsular implantation. Polypropylene is suggested as the apparent ideal loop material. PMID:304550

  19. Antireflection coatings for intraocular lenses of sapphire and fianite

    International Nuclear Information System (INIS)

    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

  20. Surgical management of astigmatism with toric intraocular lenses

    OpenAIRE

    Ventura, Bruna V.; Li Wang; Weikert, Mitchell P.; Shaun B. Robinson; Koch, Douglas D.

    2014-01-01

    Correction of corneal astigmatism is a key element of cataract surgery, since post-surgical residual astigmatism can compromise the patient's uncorrected visual acuity. Toric intraocular lenses (IOLs) compensate for corneal astigmatism at the time of surgery, correcting ocular astigmatism. They are a predictable treatment. However, accurate measurement of corneal astigmatism is mandatory for choosing the correct toric IOL power and for planning optimal alignment. When calculating the power of...

  1. Single-optic positional accommodating intraocular lenses: a review

    OpenAIRE

    Tomás Juan, Javier; Piñero Llorens, David Pablo; Larrañaga Murueta-Goyena, Ane

    2014-01-01

    Presbyopia is an age-related physiological condition that causes a gradual loss in the ability to focus on near objects, secondary to changes in zonular fibers, ciliary muscle and crystalline lens. Different surgical approaches are being pursued to surgically compensate presbyopia, such as corneal techniques or implantation of multifocal intraocular lenses (IOLs); however, their inability to restore accommodation has led to the development of single-optic positional accommodative IOLs. The ax...

  2. Clinical features of removing phakic intraocular lenses in cataract at high myopia

    Directory of Open Access Journals (Sweden)

    M. E. Konovalov

    2014-07-01

    Full Text Available Purpose: Development and an assessment of efficiency of a technique of phakic intraocular lenses (FIOL at cataract phacoemul- sification.Methods: 25 FIOL, a pupillary lens RSC-3, a posterior chamber lens, production of MNtK, Russia, and posterior chamber lens ICL S4 StAAR were removed. Before complex surgical intervention (FIOL + phacoemulsification were carried out standard ophthalmo- logic examination, and also automatic detection of density of endothelial cells.Results: the developed technique of removal of FIOL included subconjunctival anesthesia, formation of a corneal tunnel, filling of the anterior chamber viscoelastic, FIOL mobilization, removal of the bottom haptic element in the anterior chamber, removal of the top haptic element in the of anterior chamber, FIOL removal. In the early postoperative period in 8% transitory hypertensia was observed, in one case (4% cornea hypostasis developed. In 92.4% of cases of the maximal visual acuity with correction was corresponded to the planned. Loss of endothelial cells after operation made 4.8% that in full corresponds to standard loss of cells after not complicated phacoemulsification.Conclusion: the technique of removal of FIOL developed as part of this research allows enough effectively and to carry out safelyto patients surgical treatment of the complicated cataract with a phakic intraocular lenses explantation.

  3. Standardized methods for assessing the imaging quality of intraocular lenses

    Science.gov (United States)

    Norrby, N. E. Sverker

    1995-11-01

    The relative merits of three standardized methods for assessing the imaging quality of intraocular lenses are discussed based on theoretical modulation-transfer-function calculations. The standards are ANSI Z80.7 1984 from the American National Standards Institute, now superseded by ANSI Z80.7 1994, and the proposed ISO 11979-2 from the International Organization for Standardization. They entail different test 60% resolution efficiency in air, 70% resolutionefficiency in aqueous humor, and 0.43 modulation at 100 line pairs/mm in a model eye. The ISO working group found that the latter corresponds to 60% resolution efficiency in air in a ring test among eight laboratories on a sample of 39 poly(methyl) methacrylate lenses and four silicone lenses spanning the power (in aqueous humor) range of 10-30 D. In both ANSI Z80.7 1994 and ISO 11979-2, a 60% resolution efficiency in air remains an optional approval limit. It is concluded that the ISO configuration is preferred, because it puts the intraocular lens into the context of the optics of the eye. Note that the ISO standard is tentative and is currently being voted on.

  4. Effects of phacoemulsification on intraocular pressure and anterior chamber depth

    OpenAIRE

    LIU, XIN-QUAN; ZHU, HUA-YING; Su, Jing; HAO, XIAO-JUN

    2012-01-01

    The aim of this study was to investigate the effects of phacoemulsification with intraocular lens (IOL) implantation on intraocular pressure (IOP) and anterior chamber depth (ACD) in patients with cataract or cataract associated with primary angle closure (PAC). A total of 361 patients (481 affected eyes) with senile cataract (cataract group) and 44 patients (52 affected eyes) with cataract associated with PAC (cataract with PAC group) underwent phacoemulsification with IOL implantation from ...

  5. Evaluating the method increasing of toric intraocular lenses rotational stability

    Directory of Open Access Journals (Sweden)

    G. A. Fedjashev

    2015-10-01

    Full Text Available Purpose. To suggest a safe and effective way to improve the rotational stability of the position of toric the intraocular lenses in the capsular bag.Patients and methods.86 patients (97 eyes with corneal astigmatism undergoing cataract surgery and Acrysof Toric (Alcon, USA intraocular lens implantation. In 42 patients (47 eyes, the intraocular lens (IOL were implanted in accordance with the proposed invention.Results. Average rotation angle IOL implanted by traditional technology was 2,2±2,0 degrees during 12 months. In patients with IOL implanted by the proposed method, the average angle of rotation of the IOL in all operated eyes was significantly lower and amounted to 0,8±1,2 degrees (p <0,05. Сonclusion. The proposed method of fixing the toric IOL provides for prevention the IOL rotation and decentration relative to the eye optical axis, take steps to prevent phimosis anterior lens capsule, maintaining high visual function for a long time, and as there is no need for repeated surgery.

  6. Laboratory analyses of two explanted hydrophobic acrylic intraocular lenses

    Directory of Open Access Journals (Sweden)

    Yunhai Dai

    2014-01-01

    Full Text Available Two three-piece hydrophobic acrylic intraocular lenses (IOLs were explanted from two patients at 7 and 9 years, respectively, after implantation, because of poor fundus visualisation and/or a clinically significant decrease in visual acuity related to their opacified IOLs. In addition to light microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, confocal laser scanning microscopy was used for the first time to observe the explanted IOLs. The clinical aspect seemed to correspond to the phenomenon of surface light scattering, while laboratory analyses showed dense glistenings in the central layer of the IOL optic, which had no change next to the surface. Further studies on these phenomena are needed.

  7. [To guard against mistakes in selection of intraocular lenses].

    Science.gov (United States)

    He, Shou-zhi

    2008-04-01

    Development of different kinds of new intraocular lenses (IOL) provide more selections to meet various clinical requirements, which may plays an active role in making cataract surgery more perfectible. But there are many misunderstandings about how to select the proper IOL. For example, "the expensive one is the best one", "new product is absolutely perfect", and so on. Some surgeons prefer more practice and ignore the summary of the experiences. Someone unilaterally exaggerates some special function of IOL When selecting the IOL, it is a common challenge for us to fully consider the patients needs, and properly manage the relationship between the basic need and special need, and to avoid fanaticism, and provide the best benefits to the patients. PMID:18844010

  8. Extracapsular cataract extraction : the fate of retained lens material and intraocular lenses

    OpenAIRE

    Kappelhof, Johan

    1987-01-01

    textabstractThe aim of this study was to examine the fate of the lens material that remains in the eye after an extracapsular cataract extraction both with and without insertion of an intraocular lens. Apart from this, the development of precipitates on the intraocular lenses was morphologically investigated in order to get a better understanding of the interactions between eye and intraocular lens. This thesis is divided into a first part covering animal experiments and a second part about m...

  9. The effect of ionizing radiation on intraocular lenses

    International Nuclear Information System (INIS)

    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

  10. Comparative visual performance with monofocal and multifocal intraocular lenses

    Directory of Open Access Journals (Sweden)

    Gundersen KG

    2013-10-01

    Full Text Available Kjell Gunnar Gundersen,1,* Richard Potvin2,*1Privatsykehuset Haugesund, Haugesund, Norway; 2Science in Vision, Burleson, TX, USA *These authors contributed equally to this workBackground: To compare near, intermediate, and distance vision, and quality of vision using appropriate subjective questionnaires, when monofocal or apodized diffractive multifocal intraocular lenses (IOLs are binocularly implanted.Methods: Patients with different binocular IOLs implanted were recruited after surgery and had their visual acuity tested, and quality of vision evaluated, at a single diagnostic visit between 3 and 8 months after second-eye surgery. Lenses tested included an aspheric monofocal and two apodized diffractive multifocal IOLs with slightly different design parameters. A total of 94 patients were evaluated.Results: Subjects with the ReSTOR® +2.5 D IOL had better near and intermediate vision than those subjects with a monofocal IOL. Intermediate vision was similar to, and near vision slightly lower than, that of subjects with a ReSTOR® +3.0 D IOL implanted. The preferred reading distance was slightly farther out for the +2.5 D relative to the +3.0 D lens, and farthest for the monofocal. Visual acuity at the preferred reading distance was equal with the two multifocal IOLs and significantly worse with the monofocal IOL. Quality of vision measures were highest with the monofocal IOL and similar between the two multifocal IOLs.Conclusion: The data indicate that the ReSTOR +2.5 D IOL provided good intermediate and functional near vision for patients who did not want to accept a higher potential for visual disturbances associated with the ReSTOR +3.0 D IOL, but wanted more near vision than a monofocal IOL generally provides. Quality of vision was not significantly different between the multifocal IOLs, but patient self-selection for each lens type may have been a factor.Keywords: multifocal IOL, near vision, cataract, presbyopia

  11. Surgical management of astigmatism with toric intraocular lenses

    Directory of Open Access Journals (Sweden)

    Bruna V. Ventura

    2014-04-01

    Full Text Available Correction of corneal astigmatism is a key element of cataract surgery, since post-surgical residual astigmatism can compromise the patient's uncorrected visual acuity. Toric intraocular lenses (IOLs compensate for corneal astigmatism at the time of surgery, correcting ocular astigmatism. They are a predictable treatment. However, accurate measurement of corneal astigmatism is mandatory for choosing the correct toric IOL power and for planning optimal alignment. When calculating the power of toric IOLs, it is important to consider anterior and posterior corneal astigmatism, along with the surgically induced astigmatism. Accurate toric lens alignment along the calculated meridian is also crucial to achieve effective astigmatism correction. There are several techniques to guide IOL alignment, including the traditional manual marking technique and automated systems based on anatomic and topographic landmarks. The aim of this review is to provide an overview on astigmatism management with toric IOLs, including relevant patient selection criteria, corneal astigmatism measurement, toric IOL power calculation, toric IOL alignment, clinical outcomes and complications.

  12. Experiment design for through-focus testing of intraocular lenses

    Science.gov (United States)

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

    2013-11-01

    Eye models to test intraocular lenses (IOLs) in an optical bench are commonly designed in agreement with the ISO 11979-2 and 11979-9 standard requirements. However, modifications to the ISO eye model have been proposed to test IOLs in conditions closer to real human eye. Wavefront analysis and aberration characterization, wavelength dependence, efficiency, off-axis performance and imaging degradation under certain amount of misalignment can thus be measured in vitro. The main parts of the system to test IOLs are: the illumination system and object test, the eye model including the IOL immersed in a wet cell and a microscope assembled to a sensor that magnifies and captures the aerial image of the object formed by the eye model. A problem concerning the simultaneous variation of defocus and magnification arises when using the microscope to capture out-of-focus images in a through-focus study. Using the eye model, we study the problem of implementing a through-focus measurement of the imaging quality of an IOL. We find a solution based on geometrical optics and compare it with other proposals reported in the literature. The effects on the measurement of the Modulation Transfer Function and the Point Spread Function are predicted. Experimental results are obtained and discussed.

  13. Quality of vision through diffractive bifocal intraocular lenses.

    OpenAIRE

    Jay, J L; Chakrabarti, H S; Morrison, J D

    1991-01-01

    Two elderly women have each received a monofocal intraocular lens in one eye and a 3M diffractive bifocal intraocular lens in the other eye. Both eyes were shown to have equivalent retinal/neural function by measuring contrast sensitivity to laser interference fringes which bypassed refractive and other defects of the ocular media. The eyes with a bifocal intraocular lens displayed a much greater depth of focus, though at the expense of diminished contrast sensitivity compared with the normal...

  14. Drug loading of foldable commercial intraocular lenses using supercritical impregnation.

    Science.gov (United States)

    Bouledjouidja, A; Masmoudi, Y; Sergent, M; Trivedi, V; Meniai, A; Badens, E

    2016-03-16

    The drug delivery through intraocular lenses (IOLs) allows the combination of cataract surgery act and postoperative treatment in a single procedure. In order to prepare such systems, "clean" supercritical CO2 processes are studied for loading commercial IOLs with ophthalmic drugs. Ciprofloxacin (CIP, an antibiotic) and dexamethasone 21-phosphate disodium (DXP, an anti-inflammatory drug) were impregnated into foldable IOLs made from poly-2-hydroxyethyl methacrylate (P-HEMA). A first pre-treatment step was conducted in order to remove absorbed conditioning physiological solution. Supercritical impregnations were then performed by varying the experimental conditions. In order to obtain transparent IOLs and avoid the appearance of undesirable foaming, it was necessary to couple slow pressurization and depressurization phases during supercritical treatments. The impregnation yields were determined through drug release studies. For both drugs, release studies show deep and reproducible impregnation for different diopters. For the system P-HEMA/CIP, a series of impregnations was performed to delimit the experimental range at two pressures (80 and 200 bar) in the presence or absence of ethanol as a co-solvent for two diopters (+5.0 D and +21.0 D). Increase in pressure in the absence of a co-solvent resulted in improved CIP impregnation. The addition of ethanol (5 mol%) produced impregnation yields comparable to those obtained at 200 bar without co-solvent. A response surface methodology based on experimental designs was used to study the influence of operating conditions on impregnation of IOLs (+21.0 D) in the absence of co-solvent. Two input variables with 5 levels each were considered; the pressure (80-200 bar) and the impregnation duration (30-240 min). CIP impregnation yields ranging between 0.92 and 3.83 μg CIP/mg IOL were obtained from these experiments and response surface indicated the pressure as a key factor in the process. The DXP impregnation in P-HEMA was

  15. Spontaneous Scleral Perforation of an Anterior Chamber Intraocular Lens

    Science.gov (United States)

    Spierer, Oriel; O'Brien, Terrence P.

    2016-01-01

    A routine eye examination of a 69-year-old man revealed a scleral perforation of one of the haptics of the anterior chamber intraocular lens (AC IOL) which had been implanted many years ago. The patient was asymptomatic with good visual acuity. His history was negative for any trauma, eye rubbing, topical corticosteroid use, or autoimmune disease. The horizontal and vertical white-to-white diameters of the cornea in the right eye were 11.5 and 10.5 mm, respectively. Anterior segment optical coherence tomography showed the anterior chamber length to be 12.28 mm horizontally and 10.63 mm vertically. The patient underwent an IOL exchange, and the length of the explanted AC IOL was measured to be 12 mm. We speculate that the AC IOL, which was vertically aligned, was oversized. This case demonstrates the need for proper sizing and positioning of an AC IOL. In complex cases where AC IOL may be used, measuring the horizontal and vertical lengths of the anterior chamber by anterior segment optical coherence tomography prior to surgery may be useful.

  16. Anterior chamber fixation of a posterior chamber intraocular lens: A novel technique

    Directory of Open Access Journals (Sweden)

    A Sahap Kükner

    2014-01-01

    Full Text Available We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL in the anterior chamber (AC with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia.

  17. 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.

  18. Rotational stability of the AcrySof SA60TT toric intraocular lenses: A cohort study

    Directory of Open Access Journals (Sweden)

    Gale Richard

    2008-05-01

    Full Text Available Abstract Background To evaluate the rotational stability of the three types of AcrySof SA60TT toric intraocular lenses (Alcon, Switzerland in cataract surgery after the first postoperative week. Methods A retrospective study of 44 eyes in 33 patients. All patients underwent similar uncomplicated phacoemulsification cataract surgery. Seven eyes with corneal astigmatism of less than 1.5 D were implanted with the AcrySof SA60T3 intraocular lens. Seventeen eyes with astigmatism between 1.5 D and 2.25 D received the SA60T4 intraocular lens, and 20 eyes with more than 2.25 D of corneal astigmatism received the SA60T5 intraocular lens. Intraoperatively, the axis of the toric lens was aligned to the steepest axis of the corneal astigmatism. Main outcome measure was the postoperative position of the lens, assessed at 1 week and 3 months, using a specially designed angle measuring eyepiece for the slit lamp. Results There was no significant difference in the rotational stability of the three types of toric intraocular lenses. Overall, the postoperative rotation was within 5 degrees in 95% and within 2 degrees in 68% of eyes. The mean absolute rotation was 2.2 ± 2.2 degrees. No lens showed more than 9 degrees of rotation, and no lens required secondary repositioning. There was no trend for either clockwise or anti-clockwise rotation. The surgical procedure did not change the corneal astigmatism. Conclusion Once placed to it's position, each of the three types of the AcrySof SA60TT toric intraocular lenses demonstrate rotational stability in the capsular bag.

  19. Phakic anterior chamber intraocular lens (Verisyse™) implantation in children for treatment of severe ansiometropia myopia and amblyopia: Six-month pilot clincial trial and review of literature

    OpenAIRE

    Pirouzian, Amir; Ip, Kenneth C; O’Halloran, Henry S

    2009-01-01

    Purpose: The current study aims to evaluate both safety and efficacy of Verisyse™ (AMO, Irvine, CA) phakic anterior chamber intraocular lens (IOL) in the reduction of clinically significant (>−8 D) myopic anisometropia in children who are noncompliant to traditional medical treatment including spectacle correction or contact lenses. Design: Retrospective interventional case series. Methods: Six anisometropic myopic pediatric patients in one practice were identified through chart-review. None ...

  20. Astigmatism correction in cataract surgery with Rayner toric intraocular lenses

    OpenAIRE

    Painter, Sally

    2010-01-01

    Sally L Painter, Kikkeri S Arun, Jonathan K Kam, CK PatelOxford Eye Hospital, John Radcliffe Hospital, Headley Way, Headington, Oxford, United KingdomBackground: Cataract surgery is increasingly regarded as a refractive procedure. Corneal astigmatism can be reduced by the insertion of a toric intraocular lens (T-IOL). Rayner T-flex T-IOLs are licensed for the correction of astigmatism.Methods: In this retrospective study, 46 eyes from 34 patients, in whom T-IOLs were inserted, have been exami...

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

    International Nuclear Information System (INIS)

    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.

  2. [Refraction after Implantation of Multifocal and Presbyopia-Correcting Intraocular Lenses].

    Science.gov (United States)

    Kretz, F T A; Linz, K; Mueller, M; Gerl, M; Koss, M J; Gerl, R H; Auffarth, G U

    2015-08-01

    Nowadays, further developments in the field of intraocular lenses offer a higher level of spectacle independence for our patients. As light gets scattered on different focal points a wider range of defocus is created. This greater defocus area makes it more difficult for us to determine the objective or subjective refraction. This contribution is concerned with the difficulties of measuring visual acuity in different intraocular lens designs and different measurement distances. Measuring refraction after implantation of a multifocal intraocular lens is a complex procedure and the experience of the examiner plays a crucial role. Retinoscopy, keratometry and the defocus curve are reliable methods for testing, while the auto refractometer, bichromatic testing and the cross-cylinder have limitations. PMID:25927177

  3. Comparisons of amplitude of pseudoaccommodation with aspheric yellow, spheric yellow, and spheric clear monofocal intraocular lenses

    OpenAIRE

    Nishi T.; Taketani F; Ueda T; Ogata N.

    2013-01-01

    Tomo Nishi, Futoshi Taketani, Tetsuo Ueda, Nahoko Ogata Department of Ophthalmology, Nara Medical University, Kashihara City, Nara, Japan Purpose: To determine the amplitude of pseudoaccommodation and higher-order aberrations with three types of implanted monofocal intraocular lenses (IOLs): aspheric yellow (IQ); spheric yellow (NT); and spheric clear (AT). Setting: Department of Ophthalmology, Nara Medical University, Nara, Japan. Methods: We studied 60 patients who underwent small incision...

  4. Evaluation of actual retinal images produced by misaligned aspheric intraocular lenses in a model eye

    OpenAIRE

    Fujikado, Takashi

    2014-01-01

    Takashi Fujikado,1 Makoto Saika2 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan; 2Research and Development Department of Topcon Corporation, Tokyo, Japan Purpose: To examine the effect of misalignment (decentration and tilt) of intraocular lenses (IOLs) on retinal image quality using a water-immersed model eye with corneal spherical aberration adjusted to the values found in normal human eyes (spherical aberration 0.25 µm; pupil d...

  5. 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.

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

    Science.gov (United States)

    Unsal, Ugur; Baser, Gonen

    2016-01-01

    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). PMID:27340560

  7. Phacolytic glaucoma-its treatment by planned extracapsular cataract extraction with posterior chamber intraocular lens implantation

    OpenAIRE

    Singh Gurdeep; Kaur Jagmeet; Mall Sanjay

    1994-01-01

    Phacolytic glaucoma has traditionally been treated with intracapsular lens extraction to avoid any anaphylaxis. Various mechanisms have been described for the rise of intraocular pressure in these cases. The present study was undertaken to evaluate the response of extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens implantation (PC IOL) in five cases of phacolytic glaucoma that occurred between March 1989 and August 1990. A planned extracapsular cataract extractio...

  8. Audit of outcome of an extracapsular cataract extraction and posterior chamber intraocular lens training course

    OpenAIRE

    Alhassan, M; Kyari, F.; Achi, I.; Ozemela, C.; Abiose, A

    2000-01-01

    BACKGROUND—A training course for cataract surgery with intraocular lens implantation was organised in April 1997 at the National Eye Centre, Kaduna, Nigeria. Operations were performed by six Nigerian consultant ophthalmologists under the supervision of two surgeons from Aravind Eye Hospital, India.
METHODS—A total of 175 eyes with uncomplicated cataracts were operated on after careful selection. All but six patients had extracapsular cataract extraction with posterior chamber intraocular lens...

  9. AN EXPERIMENTAL STUDY OF THE INTERLEUKIN 1 LEVELS IN AQUEOUS HUMOR AFTER TRANSSCLERAL FIXATION OF INTRAOCULAR LENSES

    Institute of Scientific and Technical Information of China (English)

    周朝晖; 何守志

    1998-01-01

    Purpose. To study the interleukin 1 (IL-1) levels in aqueous humor after transscleroal fixation of intraocular lenses (IOLs) implantation in rabbits and disciss the effect of IL-1 on postoperative anterior ocular inflammation, Methods. Twenty-seven pigmented rabbits were divided into three groups: G1, transscleral fixation of posterior chamber (PC) IOLs implantation; G2, Lens of rabbits were removed without IOLs implantation; GS, the control group, without surgical intervention. On the Ist, 3rd, 7th and 14th postoperative days, aqueous humor samples were obtained. Methyl thiazolyl tetrazolium(MTT) colormetry was used to detected for the presence of IL-1. The data were analyzed hy using analysis of variance of SAS soft ware. Results. It was found that IL-1 level in aqueous humor was increased after transscleral fixation of IOLs implantatlon, IL-1 level reached its maximum on the 14th postoperative days in the IOL implanted group. IL-1 levels on 1st, 3rd, 7th and 14th days postoperatively was significantly higher (P<0. 05) in IOLs implanted group than that of only extracapsular lenses extraction but no IOLs implantation group and that of the none sttrgical intervention group. Conclusions. IL-1 levels increased had a close relationship with a specific response to IOL implantation. The increase of IL-1 may be suggested as the principal mediators of immunological and inflammlatory responses, so that may play critical role in anterior ocular inflammative response after IOL implantation.

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

    OpenAIRE

    Frank Schaeffel; Hakan Kaymak

    2014-01-01

    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 “recept...

  11. Postoperative Astigmatic Outcomes Based on the Haptic Axis of Intraocular Lenses Inserted in Cataract Surgery

    OpenAIRE

    Kim, In-Tae; Park, Hae-Young Lopilly; Kim, Hyun-Seung

    2011-01-01

    Purpose This study was conducted to compare post-operative astigmatic outcomes of two groups, with-the-rule (WTR) and against-the-rule (ATR) astigmatism patients, according to the haptic axis of intraocular lenses (IOLs) inserted in cataract surgery. Methods Seventy-two eyes with WTR astigmatism and 79 eyes with ATR astigmatism had cataract surgery through a clear corneal temporal incision. These two groups of eyes were then each divided into 2 groups based on whether the haptic axis of the i...

  12. Prospective evaluation of visual outcomes with three presbyopia-correcting intraocular lenses following cataract surgery

    OpenAIRE

    Ang RE; Martinez GA; EM Cruz; Tiongson AA; Dela Cruz AG

    2013-01-01

    RE Ang,1,2 GA Martinez,2,3 EM Cruz,1 AA Tiongson,1 AG Dela Cruz1 1Asian Eye Institute, Makati City, Philippines; 2Cardinal Santos Medical Center, San Juan City, Philippines; 3Pasig City General Hospital, Pasig City, Philippines Purpose: To compare the visual acuity and quality of vision achieved with three widely-used intraocular lenses (IOLs) in subjects with bilateral cataracts. Patients and methods: This three-arm, parallel, prospective, partially masked, single-surgeon study randomized 78...

  13. Ultraviolet or blue-filtering intraocular lenses: what is the evidence?

    Science.gov (United States)

    Downes, S M

    2016-02-01

    Cataract surgery was revolutionised by the introduction of modern intraocular lenses in the late 1940's. By the late 1960's to 1970's evidence had emerged that short-wavelength light caused phototoxicity at the retina and retinal pigment epithelium. By the early 1980's ultraviolet filters had been incorporated into intraocular lenses. This caused intense controversy, as there was concern that the UV-filtering chromophore might leach out into the eye causing toxicity. With the arrival of blue-filtering intraocular lenses (BFIOLs) in 1990's, a further debate was ignited as to their safety and potential disadvantages. Selecting the optimal performing intraocular lens to obtain the best visual performance with the fewest potential drawbacks has become complex and challenging for cataract surgeons and their patients with the wide choice of lenses available. Choosing a personalised lens to address astigmatism, presbyopia, spherical aberration, chromatic aberration, and potentially to shield the retina from short-wavelength light is now possible. The potential benefits and possible side effects of these different innovations emphasise the importance of assessing the evidence for their clinical utility, allowing the surgeon and the patient to weigh-up the risk benefit ratio and make an informed decision. The BFIOLs were developed to reduce cyanopsia, address chromatic aberration, and improve contrast sensitivity in different lighting conditions, as well as to prevent short-wavelength light reaching the retina thus potentially reducing the risk of developing age-related macular degeneration. Further design development of the BFIOLs was to mimic the natural crystalline lens absorption and transmittance properties in adulthood. Multiple publications have reported on the potential benefits and pitfalls of implanting a blue-filtering lens. The potential disadvantages raised in the literature over the last 25 years since their introduction, regarding compromise of visual

  14. Refractive errors induced by displacement of intraocular lenses within the pseudophakic eye.

    Science.gov (United States)

    Atchison, D A

    1989-03-01

    Simple methods were developed to estimate refractive errors when intraocular lenses are not fitted optimally within pseudophakic eyes. The accuracy of these methods was determined by comparing results obtained with them to results obtained by raytracing through a model eye. Accuracy was good for longitudinal displacement and tilting, and reasonable for transverse displacement. Refractive errors are related linearly to the magnitude of the longitudinal displacement, and are related to the square of the magnitude of tilt or transverse displacement. The refractive error upon transverse displacement is quadratically dependent upon lens shape. PMID:2717142

  15. Causes of elevated intraocular pressure following implantation of phakic intraocular lenses for myopia.

    Science.gov (United States)

    Almalki, Salem; Abubaker, Abdullah; Alsabaani, Nasser A; Edward, Deepak P

    2016-04-01

    The purpose of this study is to present the causes and visual acuity outcomes in patients with elevated intraocular pressure (IOP) following implantable collamer lens (ICL) implantation. A chart review identified patients who developed high IOP at any postoperative examination and a minimum follow-up period of 3 months after ICL implantation. Data are reported out to 6 months postoperatively. Outcome measures included causes of elevated IOP, best-corrected visual acuity (BCVA) at last visit, number of glaucoma medications, other interventions, and glaucomatous damage. Elevated IOP occurred in 58 (10.8 %) of 534 eyes that received ICL. The mean age was 28 ± 7.2 years. The preoperative IOP was 16.3 ± 1.2 mmHg. Elevated IOP most commonly occurred on the first postoperative day (23/58 (39.7 %) eyes) due to retained viscoelastic. This was followed by steroid response in 22/58 (37.9 %) eyes at 2-4 weeks postoperatively. IOP elevation in 6 (10.3 %) eyes was related to high ICL vault and pupillary block, and in 4 (6.9 %) eyes due to synechial angle closure. At last visit, BCVA was 20/40 or better in 56/58 (96.6 %) eyes, and 5/58 (8.6 %) eyes remained on glaucoma medications due to persistent steroid response (2 eyes), synechial angle closure glaucoma (1 eye), and other causes (2 eyes). One eye showed glaucomatous damage. Two eyes with high vault and elevated IOP underwent ICL explantation. There is a moderate risk of transiently developing elevated IOP after ICL implantation. Thorough removal of viscoelastic and use of anti-glaucoma medications during steroid use will reduce the majority of cases with postoperative IOP elevation. PMID:26265323

  16. Intraocular lens exchange through a 3.2-mm corneal incision for opacified intraocular lenses

    Directory of Open Access Journals (Sweden)

    Kubaloglu Anil

    2011-01-01

    Full Text Available Aim: The aim was to evaluate visual and refractive results and complications of intraocular lens (IOL exchange through a 3.2 mm corneal incision for opacified IOLs. Materials and Methods: This retrospective study comprised 33 eyes of 32 patients with IOL opacification requiring an IOL exchange between July 2003 and March 2007. Exchange surgery was performed through a 3.2-mm temporal clear corneal incision followed by implantation of a new foldable hydrophobic IOL. Uncorrected visual acuity (UCVA, best spectacle-corrected visual acuity (BSCVA, topographical astigmatism, and refractive cylinder were evaluated. Surgically induced astigmatism (SIA was calculated and complications were recorded. Results: Opacification was observed in 25 eyes (76% with Aqua-Sense, 3 eyes (9% with Hydroview, 3 eyes (9% with MemoryLens IOLs, and 2 eyes (6% with DgR. The mean follow-up period was 36.54 months. An uneventful IOL exchange was achieved in 18 eyes (55%. Zonular dehiscence occurred in 9 eyes (27%, and posterior capsule tear developed in 4 eyes (12%. The mean preoperative BSCVA (mean ± standard deviation, decimal scale was 0.13 ± 0.08 (mean: 20/150, range 20/2000 to 20/60 and improved to 0.63 ± 0.18 (mean: 20/32, range 20/60 to 20/20, P < 0.001. The mean SIA was 0.70 D. Seven eyes (21% had 0.5 D or lower SIA. Conclusion: IOL exchange is a technically challenging procedure with potential risks of reversing the advantages of a prior small-incision cataract surgery. The use of a small corneal incision for IOL exchange could preserve the advantages of modern phacoemulsification surgery with acceptable SIA related to the procedure.

  17. 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.

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

    International Nuclear Information System (INIS)

    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.

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

    Directory of Open Access Journals (Sweden)

    R. K. Khandal

    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.

  20. One Year Follow-Up After Veriflex Phakic Intraocular Lenses Implantation for Correction of Myopia

    Science.gov (United States)

    Pjano, Melisa Ahmedbegovic; Biscevic, Alma; Grisevic, Senad; Pidro, Ajla; Ratkovic, Mirko; Bohac, Maja; Husovic, Amila Alikadic; Gojak, Refet

    2016-01-01

    Objectives: The aim of this study was to evaluate visual and refractive outcomes after Veriflex phakic intraocular lenses (pIOL) implantation in moderately myopic eyes as well as postoperative complications. Methods: This prospective clinical study included 40 eyes of 26 patients which underwent implantation of Veriflex for correction of myopia from -6.00 to -14.50 diopters (D) in the Eye Clinic Svjetlost Sarajevo, from January 2011 to January 2014. Uncorrected distance visual acuity (UDVA), manifest residual spherical equivalent (MRSE), intraocular pressure (IOP), endothelial cell (EC) density were evaluated at one, three, six and 12 months. Other complications in postoperative period were evaluated. For statistical analysis SPSS for Windows and Microsoft Excel were used. Results: Out of 26 patients 14 had binocular and 12 monocular procedure, with mean age of 29.8±6.5 years. After 12 months mean UDVA was 0.73±0.20. Mean MRSE was -0.39±0.31D and 90% of eyes had MRSE within ±1D. EC loss was 7.18±4.33%. There was no significant change of IOP by the end of 12 months follow up period. The only intraoperative complication was hyphema and occurred in one eye. Few postoperative complications were: subclinical inflammation in three eyes (7,5%), pigment dispersion in four eyes (10%), ovalisation of papilla in 2 eyes (5%) and decentration of pIOL in 2 eyes (5%). Conclusion: Implantation of iris-claw phakic lenses Veriflex for treating moderately high myopia is a procedure with good visual and refractive results and few postoperative complications. PMID:27482131

  1. Irradiation system for two-photon induced activation of agents in novel intraocular lenses

    Science.gov (United States)

    Klämpfl, Florian; Roth, Stephan; Schmidt, Michael

    This paper presents a newly designed irradiation system for the photochemically triggered two-photon activation of an agent loaded in novel intraocular lenses. After activation, this agent suppresses the formation of after-cataract, a very common disease after the treatment of an eye cataract by implanting an intraocular lens. For this application, intrinsic safety is also important: the laser radiation is applied to one of the most light-sensitive organs: the eye. This has to be taken into account during development of the system. Moreover, the activation uses a two-photon process so a relatively small laser focus is required. To address these issues in combination with economic requirements, a mirror based objective was designed and built, specifically tailored to these needs. Besides the laser beam guidance elements, the irradiation system consists of a camera based monitoring module and an illumination unit. While the first part of the paper shows the design of the system, the second part presents the results of the characterization of the system. The paper closes with a conclusion and an outlook discussing what further development is needed to prepare the system for treatments of human eyes.

  2. New Management of Angle-closure Glaucoma by Phacoemulsification with Foldable Posterior Chamber Intraocular Lens Implantation

    Institute of Scientific and Technical Information of China (English)

    Jian Ge; Yan Guo; Yizhi Liu; Mingkai Lin; Yehong Zhuo; Bing Chen; Xiuqi Chen

    2000-01-01

    Objective: To investigate the management of angle-closure glaucoma by phacoemulsification with foldable posterior chamber intraocular lens (PC-IOL) implantation. Design: Retrospective, noncontrolled interventional case series.Participants: In 36 eyes with angle-closure glaucoma (ACG), there were 18 eyes with primary acute angle-closure glaucoma (PACG), 14 eyes with primary chronic angle-closure glaucoma (PCCG), 3 eyes with secondary acute angle-closure glaucoma (SACG) and 1 eye with secondary chronic angle-closure glaucoma (SCCG).Intervention: Phacoemulsification with posterior chamber intraocular lens implantation.Main Outcome Measures: Postoperative visual acuity, IOP, axial anterior chamber depth.Results: After a mean postoperative follow-up time of 8.81 ± 7.45 months, intraocular pressure was reduced from a preoperative mean of 23.81 ± 17.84 mmHg to a postoperative mean of 12.54 ± 4. 73 mmHg ( P = 0. 001 ). Mean anterior chamber depth was 1.75 ± 0.48 mm preoperatively and 2.29 ± 0.38 mm postoperatively ( P = 0. 000).Best spectacle-corrected visual acuity in 36 eyes ranged from 0. 01 to 0. 7 (20/200 to 20/30) postoperatively, which was better than preoperative VA ranging from hand movement to 0.4 (20/50) ( P= 0. 000).Conclusion: Phacoemulsification with posterior chamber foldable intraocular lens implantation can be a good alternative in treating angle-closure glaucoma. Eye Science 2000; 16:22 ~ 28.

  3. New Management of Angle-closure Glaucoma by Phacoemulsification with Folable Posterior Chamber Intraocular Lens Implantation

    Institute of Scientific and Technical Information of China (English)

    JianGE; YanGuo; 等

    2002-01-01

    Objective:To investigate the management of angle-closure glaucoma by phacoemulsification with foldable posterior chamber intraocular lens (PC-IOIL)implantation.Design:Retrospective,noncontrolled interventional case series.Participants:In 36 eyes with angle -closure glaucoma(ACG).there were 18eyes with primary acute angle-closure glaucoma(PACG),14 eyes with primary chonic angle -closure glaucoma(PCCG),3 eyes with secondary acute angle-closure glaucoma (SACG) and 1 eye with secondary chronic angle -closure glaucoma(SCCG).Intervention:Phacoemulsification with posterior chamber intraocular lens implantation.Main Outcome Measures:Postoperative visual acuity,IOP,axial anterior chamber depth.Results:After a mean postoperative follow -time of 8.81±7.45 months,intraocular pressure was reduced from a preoperative mean of 23.81±17.84 mmHg to a postoperative mean of 12.54±4.73mmHg(P=0.001).Mean anterior chamber depth was 1.75±0.48 mm preoiperatively and 2.29±0.38mm postoperatively(P-0.000).Best spectacle-corrected visual acuity in 36 eyes ranged from 0.01 to 0.7(20/200 to 20/30)postoperatively,which was better than preoperative VA ranging from hand movement to 0.4(20/50)(P=0.000).Conclusion:Phacoemulsification with posterior chamber foldable intraocular lens implantation can be a good alternative in treating angle-closure glaucoma.Eye Science2000;16:22-28.

  4. Intraocular lens dislocation and tube shunt in the posterior chamber: a case report

    OpenAIRE

    Moreno-Montañés, Javier; Velázquez-Villoria, Alvaro; Sabater, Alfonso L.; Salinas-Alamán, Angel

    2015-01-01

    Background To describe management of a case of intraocular lens (IOL) and capsular bag (CB) dislocation in an eye with an Ahmed glaucoma valve in the posterior chamber. Case presentation A 75-year-old pseudophakic man with open-angle glaucoma and diabetic retinopathy developed neovascular glaucoma. After two intravitreous injections of bevacizumab and panretinal photocoagulation were administered, the new vessels regressed. However, goniosynechiae were observed over 360° of the angle. An Ahme...

  5. Acute onset of retinal detachment after posterior chamber phakic intraocular lens implantation

    OpenAIRE

    Núria Planas Domènech; Luí­s Arias; Sergi Prades; Octavi Pujol; Marc Rubio; Caminal, Jose M

    2008-01-01

    Núria Planas Domènech, Luís Arias, Sergi Prades, Octavi Pujol, Marc Rubio, Jose M CaminalDepartment of Ophthalmology, Hospital Universitari de Bellvitge, L’Hospitalet de Llobregat, Barcelona, SpainCase report: A 34-year-old man with severe myopia, presented with acute visual loss in his right eye. This occurred 3 hours after a posterior chamber phakic (PCP) intraocular lens (IOL) implantation, and was associated with a rhegmatogenous retinal detachme...

  6. Retinal detachment following extracapsular cataract extraction and posterior chamber intraocular lens implantation.

    OpenAIRE

    Ho, P C; Tolentino, F I

    1985-01-01

    Fourteen cases of primary retinal detachment after extracapsular cataract extraction and posterior chamber intraocular lens implantation were treated by scleral buckling surgery. Retinal reattachment was achieved in 100% of the cases. All eyes had a postoperative visual acuity of 6/30 or better; in six eyes the visual acuity was 6/12 or better. We attributed our high anatomical success rate to early detection of the retinal detachment, good visibility of the retinal breaks, lack of inflammato...

  7. The Clinical Analysis of Secondary Glaucoma Following Posterior Chamber Intraocular Lens Implantation

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    We present 14 patients with secondary gluacoma following the implantation of a posterior chamber intraocular lens (lOLs). All patients were u-nilateral gluacoma , which developed within 1 month following the IOL implantation in 10 cases, and from 1 to 3 years in 4 cases. The angle of anterior chamber was open in 8 patients, and close in 6 ones. Seven patients required treatment of antiglaucomatous medicine; 4 patients underwent laser indecto-my and 3 patients required antiglaucoma surgery. The results s...

  8. [Optimisation of the visualisation technique for optical paths through intraocular lenses for characterisation of multifocal imaging properties of Fresnel-zone plates].

    Science.gov (United States)

    Reiß, S; Forbrig, J; Guthoff, R F; Terwee, T; Stolz, H; Siewert, S; El-Tamer, A; Hinze, U; Chichkov, B N; Stachs, O

    2014-12-01

    The utilisation of the diffractive properties of Fresnel zone plates offers the possibility of intraocular lens designs with multiple foci. Such intraocular lenses can be manufactured by two-photon polymerisation (2PP). This paper explains the underlying concept and shows the principles for visualisation of the focus properties of such implants. PMID:25519505

  9. Phacolytic glaucoma-its treatment by planned extracapsular cataract extraction with posterior chamber intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Singh Gurdeep

    1994-01-01

    Full Text Available Phacolytic glaucoma has traditionally been treated with intracapsular lens extraction to avoid any anaphylaxis. Various mechanisms have been described for the rise of intraocular pressure in these cases. The present study was undertaken to evaluate the response of extracapsular cataract extraction (ECCE with posterior chamber intraocular lens implantation (PC IOL in five cases of phacolytic glaucoma that occurred between March 1989 and August 1990. A planned extracapsular cataract extraction with can-opener capsulectomy was done in all the cases with placement of a sulcus-fixated modified J-loop Sinskey design intraocular lens. With a mean follow-up period of two years, all patients (100% maintained a normal postoperative intraocular pressure of less than 20 mm Hg without any additional medical therapy. The final best-corrected visual acuity in 4 cases (80% was 6/12 or better, while in one case it was 6/24 due to a senile maculopathy. These results show that ECCE with PC IOL implantation is a safe and efficacious method of visual rehabilitation in cases of phacolytic glaucoma

  10. Toric intraocular lenses for correction of astigmatism in keratoconus and after corneal surgery

    Directory of Open Access Journals (Sweden)

    Mol IEMA

    2016-06-01

    Full Text Available Ilse EMA Mol,1,2 Bart TH Van Dooren1,2 1Department of Ophthalmology, Amphia Hospital, Breda, 2Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands Purpose: To describe the results of cataract extraction with toric intraocular lens (IOL implantation in patients with preexisting astigmatism from three corneal conditions (keratoconus, postkeratoplasty, and postpterygium surgery.Methods: Cataract patients with topographically stable, fairly regular (although sometimes very high corneal astigmatism underwent phacoemulsification with implantation of a toric IOL (Zeiss AT TORBI 709, Alcon Acrysof IQ toric SN6AT, AMO Tecnis ZCT. Postoperative astigmatism and refractive outcomes, as well as visual acuities, vector reduction, and complications were recorded for all eyes.Results: This study evaluated 17 eyes of 16 patients with a mean age of 60 years at the time of surgery. Mean follow-up in this study was 12 months. The corrected distance Snellen visual acuity (with spectacles or contact lenses 12 months postoperatively was 20/32 or better in 82% of eyes. The mean corneal astigmatism was 6.7 diopters (D preoperatively, and 1.5 D of refractive cylinder at 1-year follow-up. No vision-compromising intra- or postoperative complications occurred and decentration or off-axis alignment of toric IOLs were not observed.Conclusion: Phacoemulsification with toric IOL implantation was a safe and effective procedure in the three mentioned corneal conditions. Patient selection, counseling, and IOL placement with optimal astigmatism correction are crucial. Keywords: toric intraocular lens, phacoemulsification, corneal astigmatism, keratoconus, postkeratoplasty, postpterygium surgery

  11. Evaluation of actual retinal images produced by misaligned aspheric intraocular lenses in a model eye

    OpenAIRE

    Fujikado T; Saika M

    2014-01-01

    Takashi Fujikado,1 Makoto Saika2 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan; 2Research and Development Department of Topcon Corporation, Tokyo, Japan Purpose: To examine the effect of misalignment (decentration and tilt) of intraocular lenses (IOLs) on retinal image quality using a water-immersed model eye with corneal spherical aberration adjusted to the values found in normal human eyes (spherical aberration 0.25 µm; pupil diame...

  12. Prospective evaluation of visual outcomes with three presbyopia-correcting intraocular lenses following cataract surgery

    Directory of Open Access Journals (Sweden)

    Ang RE

    2013-09-01

    Full Text Available RE Ang,1,2 GA Martinez,2,3 EM Cruz,1 AA Tiongson,1 AG Dela Cruz1 1Asian Eye Institute, Makati City, Philippines; 2Cardinal Santos Medical Center, San Juan City, Philippines; 3Pasig City General Hospital, Pasig City, Philippines Purpose: To compare the visual acuity and quality of vision achieved with three widely-used intraocular lenses (IOLs in subjects with bilateral cataracts. Patients and methods: This three-arm, parallel, prospective, partially masked, single-surgeon study randomized 78 subjects to receive bilateral Crystalens® Advanced Optics (AO accommodating IOLs, AcrySof® IQ ReSTOR® +3.0 multifocal IOLs, or TECNIS® Multifocal IOLs. Examinations were assessed through days 120 to 180. Results: The Crystalens AO group had statistically significantly better monocular and binocular, high-contrast (HC and low-contrast (LC uncorrected intermediate visual acuity, HC and LC distance-corrected intermediate visual acuity, and significantly fewer monocular and binocular halos and starbursts than did the ReSTOR and TECNIS groups. Monocular and binocular, HC and LC uncorrected near visual acuity exhibited no significant differences among the three lenses. For monocular and binocular HC distance-corrected near visual acuity, the Crystalens AO performed significantly better than the TECNIS and was not significantly different from the ReSTOR. For monocular and binocular LC distance-corrected near visual acuity, the Crystalens AO performed significantly better than both the ReSTOR and the TECNIS. Contrast sensitivity was clinically similar between groups. The Crystalens AO produced statistically fewer halos and starbursts. Conclusion: All three IOLs had excellent uncorrected acuity results at all distances and had good safety, confirming the established safety and effectiveness of these IOLs. Distance and near vision were similar between all three IOLs, and the Crystalens AO provided statistically significantly better intermediate vision. Keywords

  13. Toric intraocular lenses for correction of astigmatism in keratoconus and after corneal surgery

    Science.gov (United States)

    Mol, Ilse EMA; Van Dooren, Bart TH

    2016-01-01

    Purpose To describe the results of cataract extraction with toric intraocular lens (IOL) implantation in patients with preexisting astigmatism from three corneal conditions (keratoconus, postkeratoplasty, and postpterygium surgery). Methods Cataract patients with topographically stable, fairly regular (although sometimes very high) corneal astigmatism underwent phacoemulsification with implantation of a toric IOL (Zeiss AT TORBI 709, Alcon Acrysof IQ toric SN6AT, AMO Tecnis ZCT). Postoperative astigmatism and refractive outcomes, as well as visual acuities, vector reduction, and complications were recorded for all eyes. Results This study evaluated 17 eyes of 16 patients with a mean age of 60 years at the time of surgery. Mean follow-up in this study was 12 months. The corrected distance Snellen visual acuity (with spectacles or contact lenses) 12 months postoperatively was 20/32 or better in 82% of eyes. The mean corneal astigmatism was 6.7 diopters (D) preoperatively, and 1.5 D of refractive cylinder at 1-year follow-up. No vision-compromising intra- or postoperative complications occurred and decentration or off-axis alignment of toric IOLs were not observed. Conclusion Phacoemulsification with toric IOL implantation was a safe and effective procedure in the three mentioned corneal conditions. Patient selection, counseling, and IOL placement with optimal astigmatism correction are crucial. PMID:27382249

  14. Interaction with therapeutic soft contact lenses affects the intraocular efficacy of tropicamide and latanoprost in dogs.

    Science.gov (United States)

    Hatzav, M; Bdolah-Abram, T; Ofri, R

    2016-04-01

    Therapeutic soft contact lenses (TSCLs) are frequently used to support or protect the cornea during healing. Our aim was to quantitatively evaluate the efficacy of topical medications in TSCL-fitted dogs and determine whether it is affected by the presence of TSCLs. In Phase I, pupil diameter was measured in eyes treated with tropicamide and in eyes covered with TSCLs and then treated with tropicamide, with 1-week intervals between sessions. In Phase II, intraocular pressure (IOP) was measured in uncovered and TSCL-covered eyes treated with latanoprost, with 1-week intervals between sessions. Tropicamide caused significant mydriasis in both uncovered and TSCL-covered eyes (P = 0.005). On the other hand, latanoprost caused a significant decrease in IOP when applied to uncovered eyes (P = 0.002), but had no significant effect on IOP when applied to TSCL-covered eyes (P = 0.7). As we used the same dogs and identical TSCLs throughout the study, we conclude that the different outcomes of the two drugs are due to properties of the drugs themselves, or their formulations, affecting their interaction with the TSCLs. The clinical efficacy of topical drugs applied to TSCL-covered eyes may have to be determined for each drug and/or formulation. PMID:26411631

  15. Spontaneous fracture of an implanted posterior chamber polyimide intraocular lens haptic: A case report

    Directory of Open Access Journals (Sweden)

    Haemin Kang

    2014-01-01

    Full Text Available A 57-year-old male patient visited our clinic for decreased visual acuity in the right eye for 10 days. He denied any trauma history, but recalled that the symptom developed after straining. He had undergone uncomplicated phacoemulsification and posterior chamber intraocular lens (IOL implantation in the bag of the right eye 11 years ago. The IOL was a three-piece silicone polyimide-haptics design. On slit-lamp examination, the IOL optic and proximal part of nasal fractured haptic were found in the anterior chamber. The distal part of fractured haptic was observed in the capsular bag. He underwent IOL exchange. The fracture site of the haptic was near the optic-haptic junction. This is the unique case report of a spontaneous fracture of an implanted posterior chamber polyimide IOL haptic, which implies the possibility of IOL haptic fracture in various haptic materials.

  16. 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.

  17. An investigation of the effect of silicone oil on polymer intraocular lenses by means of PALS, FT-IR and Raman spectroscopies.

    Science.gov (United States)

    Chamerski, Kordian; Lesniak, Magdalena; Sitarz, Maciej; Stopa, Marcin; Filipecki, Jacek

    2016-10-01

    The effect of the polydimethylsiloxane (PDMS) based silicone oil, that is widely used in vitreoretinal surgery, on internal structures of the polymer intraocular lenses was investigated. The effect of PDMS was studied on the polymethyl methacrylate (PMMA) rigid lenses and poly(2-hydroxyethyl methacrylate) (PHEMA) flexible lenses. The research was carried out by means of the positron lifetime spectroscopy (PALS) as well as the infrared spectroscopy (FT-IR) and the Raman spectroscopy (RS). The studies involving the use of PALS and FT-IR methods have revealed that the PHEMA based lenses absorbed, whereas the PMMA lenses did not absorb, silicone oil. The results obtained with the use of the RS method were inconclusive, probably due to the too low intensity of the characteristic PDMS bands. The evidence from this study was discussed in terms of physics and related to the clinical use of both silicone oil and intraocular lenses. PMID:27261889

  18. Uveitis-glaucoma-hyphema syndrome caused by posterior chamber intraocular lens--a rare complication in pediatric cataract surgery.

    Science.gov (United States)

    Lin, Chun-Ju; Tan, Chau-Yi; Lin, Szu-Yuan; Jou, Jieh-Ren

    2008-01-01

    We report a case of postoperative uveitis-glaucome-hyphema (UGH) syndrome following pediatric cataract surgery due to posterior chamber intraocular lens (PC-IOL). Slit-lamp examination revealed the optic of PC-IOL migrated into anterior chamber. The PC-IOL explantation was performed and ocular inflammation subsided. PMID:19230361

  19. Surface characterization of polymer-drug modified vascular stents and intraocular lenses

    Science.gov (United States)

    Elachchabi, Amin

    Two of the most important medical devices in clinical use today are endoluminal stents and intraocular lenses (IOLs). In both devices, surface and interfacial properties are of basic importance in the development and clinical performance of these devices. Drug eluting stents have revolutionized the world of interventional cardiology. Research reported here was devoted to the design and development of new drug eluting stents wherein the metallic backbone is completely embedded in a polymeric matrix used also as a drug reservoir. This design, using silicone-drug compositions can lead to higher drug payloads, less tissue damage during angioplasty balloon/stent expansion, and the novel capability of delivering multiple drugs. The adhesion of the polymeric coating to the metallic stent is essential and has not been adequately reported previously. The adhesion of polydimethylsiloxane (PDMS) coatings to a stainless steel stent substrate was shown to be enhanced by the application of mixtures of tetra-n-propyl silicate, tetrabutyltitanate, tetra-2-methoxyethoxysilane, and 3-(trimethoxysilyl)propyl methacrylate coupling agents. Additionally, the effect of drug loading on the stress/strain properties of the polymeric coating is of basic importance. The tensile strength and percent elongation of dexamethasone loaded PDMS films was shown to remain satisfactory for stent coatings at low concentrations (less than 1%) but decreased as the concentrations of dexamethasone in PDMS was increased to 5%. The release of multiple therapeutic agents from PDMS coatings to reduce in-stent restenosis has not been previously reported. The release profile of Paclitaxel, dexamethasone 21-acetate, and their combination from PDMS coatings was studied using high precision liquid chromatography (HPLC). Although dexamethasone release was reduced by paclitaxel, paclitaxel release was unaffected by combination with dexamethasone. Paclitaxel release from the polymeric matrices was shown to inhibit

  20. Spontaneous fracture of an implanted posterior chamber polyimide intraocular lens haptic: A case report

    OpenAIRE

    Haemin Kang; Kyung Eun Han; Tae-im Kim; Eung Kweon Kim

    2014-01-01

    A 57-year-old male patient visited our clinic for decreased visual acuity in the right eye for 10 days. He denied any trauma history, but recalled that the symptom developed after straining. He had undergone uncomplicated phacoemulsification and posterior chamber intraocular lens (IOL) implantation in the bag of the right eye 11 years ago. The IOL was a three-piece silicone polyimide-haptics design. On slit-lamp examination, the IOL optic and proximal part of nasal fractured haptic were found...

  1. Correction of high myopia with foldable Artiflex Phakic intraocular lenses: 1 year follow-up results.

    Directory of Open Access Journals (Sweden)

    Hassan Hashemi

    2013-09-01

    Full Text Available To assess the one year results of Artiflex Phakic intraocular lens (IOL implantation in the treatment of high myopia. In this non-random interventional study, myopic patients with spherical equivalent worse than -5.0 diopters (D who were not eligible for laser surgery were assessed. All patients had refraction, uncorrected and best corrected visual acuity tests (UCVA and BCVA, endothelial cell count (ECC, and measurement of the anterior chamber depth and intraocular pressure before surgery and at 1, 3, 6, and 12 months after surgery. Main outcome measures of this study were refractive stability, refractive predictability, safety, and efficacy after implanting Artiflex IOLs. We studied 53 eyes of 20 female and 8 male patients. The mean preoperative spherical equivalent was -10.22±3.02 D which reached -0.69±1.08 D one year after surgery (P<0.001. On the last follow-up visit, 75% of the eyes were within +0.5 D of emmetropia, 2 eyes had lost one line of BCVA, 18.75% had gained one line and 31.25% had gained 2 or more lines of BCVA. Others showed no change in BCVA. At one year after surgery, 72.2% of the eyes had 20/25 vision or better. The safety and efficacy indices were 1.16 and 1.05, respectively. ECC showed 3.04% decrease (P=0.176. In cases where laser surgery is not an option for myopic patients, use of Artiflex IOLs can have good results with acceptable safety and efficacy.

  2. Effect of Anterior Chamber Depth on Intraocular Pressure after Uneventful Phacoemulsification Surgery in Nonglaucomatous Eyes with CataractEffect of Anterior Chamber Depth on Intraocular Pressure after Uneventful Phacoemulsification Surgery in Nonglaucomatous Eyes with CataractEffect of Anterior Chamber Depth on Intraocular Pressure after Uneventful Phacoemulsification Surgery in Nonglaucomatous Eyes with Cataract

    OpenAIRE

    Tansu Gönen; Kadircan Keskinbora; Fatih Horozo¤lu; Özkan Sever; Mustafa Yaflar

    2011-01-01

    Purpose: To evaluate the effect of preoperative anterior chamber depth (ACD) on intraocular pressure (IOP) after uneventful phacoemulsification and intraocular lens (IOL) implantation in nonglaucomatous eyes. Material and Method: The medical records of fifty-five patients (30 male and 25 female) were reviewed retrospectively. The patients who had undergone uneventful phacoemulsification and IOL implantation were divided into two groups according to the values of preoperative ACD: ...

  3. Visian implantable contact lens versus AcrySof Cachet phakic intraocular lenses: comparison of aberrmetric profiles

    Directory of Open Access Journals (Sweden)

    Hosny MHM

    2013-07-01

    Full Text Available Mohamed HM Hosny, Ahmad MM ShalabyDepartment of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, EgyptPurpose: To evaluate the in vivo aberrometric performance of two phakic intraocular lenses (PIOLs; the Visian implantable contact lens (ICL and the AcrySof Cachet PIOL.Methods: Thirty eight eyes from 29 patients with an age range of 23–32 years and more than 9 D of myopia were divided into two groups; one group of 20 eyes received a Visian ICL model V4c, another group of 18 eyes received an AcrySof Cachet PIOL. Total higher order aberrations (HOAs root mean square, total coma, and total spherical aberrations were recorded pre and 6 weeks postoperatively to evaluate and compare the aberrometric performance of the Visian ICL and the AcrySof Cachet PIOL implanted in highly myopic patients.Results: Preoperatively, there were no significant differences in any studied parameters, except for preoperative spherical equivalent. Postoperatively, there were no statistically significant differences in the induction of HOAs between both PIOLs. The reduction in spherical aberrations was statistically significant in each group as well as in all study patients.Conclusion: Both AcrySof Cachet PIOL and ICLs are effective phakic implants to correct high refractive errors. They both induce small amounts of negative spherical aberration that do not affect the total HOAs, yet reduce the positive ocular spherical aberration. This result is expected to improve the quality of vision in such patients.Keywords: high myopia, higher order aberrations, refractive procedures, phakic implants

  4. Personal A-constant in relation to axial length with various intraocular lenses

    Directory of Open Access Journals (Sweden)

    Mohamed A Eldaly

    2014-01-01

    Full Text Available Purpose: To study the relationship between the axial length and personal A-constant for the 1-piece Tecnis (Abbott ZCB00, AcrySof MA60AC (Alcon and the Quatrix aspheric preloaded (CROMA intraocular lenses (IOL. Materials and Methods: Patients matching the inclusion criteria were further subdivided according to the implanted IOL in this prospective comparative study. The obtained refractive outcomes were introduced into the formula installed in the biometry machine (Humphrey model 820 ultrasonic biometer to obtain the personal A-constant for each eye. Polynomial regression analysis was done to study the individualized A-constant for each type of IOL in relation to preoperative axial length measurement. Results: Two hundred and forty five eyes of 186 patients were enrolled into this study, of whom 73 eyes with Tecnis 1-piece, 116 eyes with MA60AC, and 56 eyes with Quatrix. The median of personalized A-constant for Tecnis 1-piece, MA60AC, and Quatrix were 119.21 (SD 1.3, Std. Mean error 0.15, 119 (SD 1.2, Std. Mean error 0.11 and 120.4 (SD 1.2, Std. Mean error 0.16 respectively. Regression plots for the same range of axial length among all the groups showed that the Tecnis1 group followed the same pattern of the Quatrix group in which there was a linear relationship of a trend towards myopia when the axial length had increased and a hyperopic shift when decreased. This relationship changed into a plateau when the axial length became in the range of 23.5 mm to 27 mm in the MA60AC group. Conclusions: Personal A-constant follows different trends with different IOLs even for the same range of axial length.

  5. 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.

  6. Acute onset of retinal detachment after posterior chamber phakic intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Núria Planas Domènech

    2008-03-01

    Full Text Available Núria Planas Domènech, Luís Arias, Sergi Prades, Octavi Pujol, Marc Rubio, Jose M CaminalDepartment of Ophthalmology, Hospital Universitari de Bellvitge, L’Hospitalet de Llobregat, Barcelona, SpainCase report: A 34-year-old man with severe myopia, presented with acute visual loss in his right eye. This occurred 3 hours after a posterior chamber phakic (PCP intraocular lens (IOL implantation, and was associated with a rhegmatogenous retinal detachment. Retinal retachment surgery was performed without complications, with the outcome showing good anatomical and functional results during a 2-year follow-up period.Discussion: Despite the fact that several authors have described retinal detachments following PCP IOL implantation in highly myopic patients, there is no evidence that this procedure increases the risk of retinal detachment in these patients. The occurrence of the retinal detachment immediately after the phakic IOL implantation supports the hypothesis that the surgical procedure could induce iatrogenic changes in patients with high myopia, which could increase the incidence of retinal detachment. In contrast to other reports, the interval between the PCP IOL implantation and the retinal detachment was only 3 hours in our patient. We believe this demonstrates the importance of performing a complete preoperative vitreoretinal examination in patients with severe myopia.Keywords: retinal detachment, phakic intraocular lens, myopia

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

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    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

  8. The Management of a Patient with Elevated Intraocular Pressure Resistant to Medical Treatment: Anterior Chamber Irrigation

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    Abdullah Beyoğlu

    2014-10-01

    Full Text Available A 7-year-old male patient was medically treated in another center for hyphema which occurred after blunt trauma to his right eye. He was admitted to our clinic when his visual acuity decreased after being discharged. Biomicroscopic examination revealed total hyphema. Intraocular pressure (IOP was 48 mm Hg in the right eye with Goldmann applanation tonometry. Since IOP could not be managed by medical therapy and there was no regression in hyphema, anterior chamber was irrigated. As in our case, it should not be forgotten that re-hemorrhage may occur in the first week of hyphema during childhood. Moreover, surgical treatment should be considered when hemorrhage does not regress with medical treatment, increased IOP persists, and when there is a risk of corneal endothelial staining (corneal blood staining. (Turk J Ophthalmol 2014; 44: 400-2

  9. Significance of intraocular lens power calculation.

    OpenAIRE

    M. Singh; Dahalan, A

    1987-01-01

    A total of 94 patients underwent extracapsular cataract extraction and insertion of Sinsky style two-loop posterior chamber intraocular lenses. Forty-six eyes received a standard power IOL and 48 eyes were given a preoperatively calculated IOL. A significant difference was found in the two groups with regard to the postoperative refractive error and uncorrected visual acuity.

  10. Visual acuity after trans-scleral sutured posterior chamber intraocular lens

    International Nuclear Information System (INIS)

    To determine the changes in visual acuity in patients undergoing Trans-Scleral Sutured Posterior Chamber Intra-Ocular Lens (TSSPCIOL) implantation at a tertiary care hospital in Karachi, Pakistan. Study Design: Case series. Place and Duration of Study: LRBT Tertiary Eye Hospital, Karachi, from January 2006 to December 2010. Methodology: Records of all patients undergoing implantation of TSSPCIOL were reviewed. Patients with diagnosed glaucoma, diabetic retinopathy, macular degeneration, history of recurrent uveitis, corneal haze or central corneal scars were excluded. For the final analysis, 70 eyes out of a total of 75 were selected. Main outcomes of interest were pre and postoperative visual acuities and surgical complications. SPSS 21 was used for data analysis. Results: Pre-operatively, the average Best Spectacle-Corrected Visual Acuity (BSCVA) was 6/36 on the Snellen chart. This improved to 6/12 postoperatively. The mean improvement seen was 2.4 lines on the Snellen chart (p < 0.05). Complications include transient intraocular pressure elevation in 25 eyes (36%), IOL tilt in 4 eyes (7.1%), Cystoid Macular Edema (CME) in 4 eyes (5.7%), vitreous haemorrhage in 2 eyes (2.9%), hyphema in 2 eyes (2.9%), uveitis in 1 eye (1.4%), and retinal detachment 1 eye (1.4%). No IOL subluxation, suture erosion, iris capture, choroidal effusion or endophthalmitis was encountered and no re-operations were needed. Conclusion: TSSPCIOLs are a good management option for patients with aphakia in whom PC IOLs cannot be placed. (author)

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

    International Nuclear Information System (INIS)

    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

  12. Comparative Assessment of Implantation of Bifocal Diffractiverefractive and Monofocal Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Kh.P. Takhchidi

    2009-03-01

    Full Text Available ABSTRACT Purpose To assess the functional results of implantation of bifocal diffractiverefractive and monofocal lenses. Material and methods Long-term visual functions in patients with bifocal diffractive-refractive lenses (MIOL-Accord, AcrySof Restor ® and monofocal lens (MIOL-2 were examined. Postop refraction, distance and near visual acuity, visual acuity at low-contrast values and contrast sensitivity were evaluated. Results Distance visual acuity in patients with MIOL-Accord and AcrySof Restor® did not differ from the visual acuity in patients with MIOL-2. Uncorrected and corrected near visual acuity was better in eyes with diffractive lenses. Visual acuity at low-contrast values and with glare, contrast sensitivity in patients with diffractive lenses were comparable (p>0,05, but were slight lower than those with the monofocal lens. Conclusion Despite different design the bifocal diffractive-refractive lenses MIOLAccord and AcrySof Restor® provided comparable postop visual functions. Uncorrected near visual acuity in patients with the multifocal lens was better than in monofocal patients. Uncorrected distance vision show comparable results in multifocal and monofocal patients. Visual acuity at low-contrast values and contrast sensitivity with glare in patients with diffractive lenses were slight lower than with the monofocal lens.

  13. Corneal Endothelial Cell Changes Due to Combined Phacoemulsification-Posterior Chamber Intraocular Lens Implantation and Transpupillary Silicone Oil Removal

    OpenAIRE

    Mehmet Hanifi Alp; Haluk Esgin

    2014-01-01

    Objectives: The aim of this study was to evaluate the effects of combined phacoemulsification-posterior chamber intraocular lens (PCIOL) implantation and removal of transpupillary silicone oil on the corneal endothelial cell layer. Materials and Methods: In this study, we included seven eyes of 7 patients who had intravitreal hemorrhage resulting from retinal detachment or tractional retinal detachment due to proliferative diabetic retinopathy and who underwent pars plana vitrectomy ...

  14. Evaluation of pars plana sclera fixation of posterior chamber intraocular lens

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    Fangju Han

    2014-01-01

    Full Text Available Purpose: The purpose of this study was to evaluate the clinical efficacy and safety of modified posterior chamber intraocular lens (PCIOL implantation with transscleral fixation. Design and Setting: This is a study, which is conducted at Department of Ophthalmology, Jinan Eye Hospital, Jinan Second People′s Hospital. Materials and Methods: A total of 82 patients who were scheduled for sutured PCIOL were divided randomly into modified and conventional groups. The former underwent PCIOL through pars plana fixation with knot buried and without scleral flap and the latter underwent transscleral fixation of PCIOL in the ciliary sulcus. The main outcome measures included operative time, postoperative visual acuity, and postoperative complications. Results: The mean operative time of the modified group was 39.95 ± 5.87 min, which was significantly less than that of the conventional group (45.77 ± 5.21 min; P < 0.05. No difference was found in postoperative visual acuity between the two groups. There were no significant postoperative complications, including knot exposure, endophthalmitis, and retinal detachment in either group. The optical clamping of PCIOL was prone to occur in the conventional group. Conclusion: Modified sutured PCIOL implantation is a safe, effective, and feasible technique for the correction of aphakia in eyes without adequate posterior capsular support.

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

    OpenAIRE

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

    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 ...

  16. Toric intraocular lenses for correction of astigmatism in keratoconus and after corneal surgery

    OpenAIRE

    Mol, Ilse

    2016-01-01

    Ilse EMA Mol,1,2 Bart TH Van Dooren1,2 1Department of Ophthalmology, Amphia Hospital, Breda, 2Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands Purpose: To describe the results of cataract extraction with toric intraocular lens (IOL) implantation in patients with preexisting astigmatism from three corneal conditions (keratoconus, postkeratoplasty, and postpterygium surgery).Methods: Cataract patients with topographically stable, fairly regular (although sometim...

  17. Comparison of retinal image quality with spherical and customized aspheric intraocular lenses

    OpenAIRE

    Guo, Huanqing; Goncharov, Alexander V.; Dainty, Chris

    2012-01-01

    We hypothesize that an intraocular lens (IOL) with higher-order aspheric surfaces customized for an individual eye provides improved retinal image quality, despite the misalignments that accompany cataract surgery. To test this hypothesis, ray-tracing eye models were used to investigate 10 designs of mono-focal single lens IOLs with rotationally symmetric spherical, aspheric, and customized surfaces. Retinal image quality of pseudo-phakic eyes using these IOLs together with individual variati...

  18. Experience with extracapsular extraction and binkhorst 2-loop intraocular lenses: preliminary communication.

    OpenAIRE

    Marsh, R J; Andrew, N C

    1981-01-01

    Extracapsular cataract extraction and implantation of a Binkhorst 2-loop intraocular lens were performed on 50 patients. The majority of the patients achieved a corrected postoperative acuity of 6/9. Operative, immediate postoperative and late postoperative complications are discussed. The commonest postoperative complication was the formation of a dense capsular membrane which required capsulotomy in 9 patients. Suggestions are put forward for improving the result of this rewarding operation.

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

    OpenAIRE

    Wong, S Chien; Ramkissoon, Yashin D; Lopez, Mauricio; Page, Kristopher; Ivan P. Parkin; 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...

  20. A comparison of anterior and posterior chamber lenses after cataract extraction in rural Africa: a within patient randomised trial

    OpenAIRE

    Waddell, K M; Reeves, B C; Johnson, G J

    2004-01-01

    Background: Extracapsular cataract extraction (ECCE) with a posterior chamber intraocular lens (PC IOL) is the preferred method of cataract surgery in developed countries. However, intracapsular cataract extraction (ICCE) with an anterior chamber lens (AC IOL) may be appropriate in rural Africa. A randomised controlled trial was carried out to compare these surgical strategies.

  1. Phakic anterior chamber intraocular lens (Verisyse™) implantation in children for treatment of severe ansiometropia myopia and amblyopia: Six-month pilot clincial trial and review of literature

    Science.gov (United States)

    Pirouzian, Amir; Ip, Kenneth C; O’Halloran, Henry S

    2009-01-01

    Purpose: The current study aims to evaluate both safety and efficacy of Verisyse™ (AMO, Irvine, CA) phakic anterior chamber intraocular lens (IOL) in the reduction of clinically significant (>−8 D) myopic anisometropia in children who are noncompliant to traditional medical treatment including spectacle correction or contact lenses. Design: Retrospective interventional case series. Methods: Six anisometropic myopic pediatric patients in one practice were identified through chart-review. None of the patients were compliant with specatacle correction or contact lens wear and as a result had dense amblyopia of less than 20/400 by Snellen or Allen visual acuity (mean 6 lines was achieved in four patients (mean visual acuity of 20/70 at six months). Improvement in stereoacuity was noted in all six patients (from total mean zero seconds-arc to six-months post-operative mean of 500 seconds-arc by randot stereoacuity testing). Improvement of >2 lines of visual acuity lines was achieved in the other two patients. No patient lost any lines of visual acuity. Enhanced physical activity, coordination, and improved social interaction were noted in patients and were reported by the parents. No intra/post-operative complications were noted. Discussion: Irreversible or intractable amblyopia secondary to severe anisometropic myopia is a serious medical concern in the pediatric population. Failure of compliance with contact lens therapy consistently leads to visual loss. Anterior chamber phakic IOLs may provide a safe alternative in treatment of noncompliant anisometropic myopic patients who do not accept spectacle wear or contact lens therapy. Conclusion: To reduce or eliminate highly significant anisometropic myopia in children who are noncompliant with traditional medical treatment, phakic anterior chamber IOL implantation may be considered as an alternative modality of treatment. PMID:19668592

  2. A truly knotless technique for scleral fixation of intraocular lenses: Two-year results

    Directory of Open Access Journals (Sweden)

    Naresh K Yadav

    2012-01-01

    Full Text Available Scleral fixated intraocular lens (SFIOL is a safe and effective option for managing optical aphakia. Suture related complications like suture erosion, suture breakage, endophthalmitis, etc. are unique to SFIOL. The knots can be covered by partial thickness flaps or they can be rotated into scleral tissues without flaps to reduce the complications. We performed a recently described novel technique which obviates the need for knot and scleral flaps in securing the SFIOL. This novel 2-point Ab externo knotless technique may reduce the knot related problems. Twenty-three eyes undergoing this knotless SFIOL procedure were analyzed for intraoperative and postoperative complications. Twenty-two eyes either maintained or improved on their preoperative vision. All patients had a minimum follow-up of 24 months.

  3. Phakic anterior chamber intraocular lens (Verisyse™ implantation in children for treatment of severe ansiometropia myopia and amblyopia: Six-month pilot clincial trial and review of literature

    Directory of Open Access Journals (Sweden)

    Amir Pirouzian

    2009-06-01

    Full Text Available Amir Pirouzian1,3, Kenneth C Ip2, Henry S O’Halloran31The Permanente Medical Group, Santa Clara, CA, USA; 2The Permanente Medical Group, San Francisco, CA, USA; 3Rady’s Children’s Hospital of San Diego, San Diego, CA, USAPurpose: The current study aims to evaluate both safety and efficacy of Verisyse™ (AMO, Irvine, CA phakic anterior chamber intraocular lens (IOL in the reduction of clinically significant (>-8 D myopic anisometropia in children who are noncompliant to traditional medical treatment including spectacle correction or contact lenses.Design: Retrospective interventional case series.Methods: Six anisometropic myopic pediatric patients in one practice were identified through chart-review. None of the patients were compliant with specatacle correction or contact lens wear and as a result had dense amblyopia of less than 20/400 by Snellen or Allen visual acuity (mean <20/400. All patients underwent Verisyse™ phakic IOL implantation in the more myopic eye by one surgeon (AP. Pre- and post-operative visual acuity, anterior/posterior segment examination, stereoacuity, axial biometry measurements, cycloplegic refraction, and endothelial cell counts were performed in all patients whenever feasible.Results: The age of patients ranged from 5–11 years. The mean post-operative follow-up time was six months from the time of IOL insertion. Improvement in visual acuity >6 lines was achieved in four patients (mean visual acuity of 20/70 at six months. Improvement in stereoacuity was noted in all six patients (from total mean zero seconds-arc to six-months post-operative mean of 500 seconds-arc by randot stereoacuity testing. Improvement of >2 lines of visual acuity lines was achieved in the other two patients. No patient lost any lines of visual acuity. Enhanced physical activity, coordination, and improved social interaction were noted in patients and were reported by the parents. No intra/post-operative complications were noted

  4. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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. PMID:26294964

  7. Surface modification of acrylate intraocular lenses with dielectric barrier discharge plasma at atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    WANG Yao; LIU ZhenMei; XU ZhiKang; YAO Ke

    2009-01-01

    Surface modification with dielectric barrier discharge (DBD) plasma was carried out at atmospheric pressure (argon as the discharge gas) to improve the biocompatibility of hydrophobic acrylate intraocular lens (IOL). Changes of the plasma-treated IOL surface in chemical composition,morphology and hydrophilicity were comprehensively evaluated by X-ray photoelectron spectroscopy (XPS),field emission scanning electron microscopy (FESEM),atomic force microscopy (AFM) and water contact angle (WCA) measurements. The surface biocompatibility of the untreated and plasma-treated IOLs was compared with the adhesion behavior of platelets,macrophages and lens epithelial cells (LECs) in vitro. After DBD plasma treatment,the hydrophilicity of the IOL surface was obviously improved. The changes in WCA with treatment extension may be attributed to both the introduction of oxygen or/and nitrogen-containing polar groups and the increase of surface roughness induced by plasma etching effect. The existence of low molecular weight oxidized material (LMWOM) was proved on the plasma treated IOL which was caused by the chain scission effect of the plasma treatment. The plasma-treated lOLs resisted the adhesion of platelets and macrophages significantly. The LECs spreading and proliferation were postponed on the lOLs plasma-treated for more than 180 s,with a well maintained epithelial phenotype of LECs. The IOL biocompatibility was improved after the DBD plasma treatment. We speculate that slighter foreign-body reaction and later incidence of anterior capsule opacification (ACO) may be expected after implantation of the argon DBD plasma-treated IOL.

  8. Surface modification of acrylate intraocular lenses with dielectric barrier discharge plasma at atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Surface modification with dielectric barrier discharge(DBD) plasma was carried out at atmospheric pressure(argon as the discharge gas) to improve the biocompatibility of hydrophobic acrylate intraocular lens(IOL).Changes of the plasma-treated IOL surface in chemical composition,morphology and hydrophilicity were comprehensively evaluated by X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM) and water contact angle(WCA) measurements.The surface biocompatibility of the untreated and plasma-treated IOLs was compared with the adhesion behavior of platelets,macrophages and lens epithelial cells(LECs) in vitro.After DBD plasma treatment,the hydrophilicity of the IOL surface was obviously improved.The changes in WCA with treatment extension may be attributed to both the introduction of oxygen or/and nitrogen-containing polar groups and the increase of surface roughness induced by plasma etching effect.The existence of low molecular weight oxidized material(LMWOM) was proved on the plasma-treated IOL which was caused by the chain scission effect of the plasma treatment.The plasma-treated IOLs resisted the adhesion of platelets and macrophages significantly.The LECs spreading and proliferation were postponed on the IOLs plasma-treated for more than 180 s,with a well maintained epithelial phenotype of LECs.The IOL biocompatibility was improved after the DBD plasma treatment.We speculate that slighter foreign-body reaction and later incidence of anterior capsule opacification(ACO) may be expected after implantation of the argon DBD plasma-treated IOL.

  9. Tilt and decentration tolerance of intraocular lenses: measurements with an improved mechanical model eye

    Science.gov (United States)

    Traxler, Lukas; Reutterer, Bernd; Bayer, Natascha; Rank, Elisabet; Krause, Sylvio; Beckert, Erik; Drauschke, Andreas

    2016-03-01

    Cataract, a clouding of the crystalline eye lens, is the leading cause of blindness. It can effectively be treated by cataract surgery, where the clouded lens is replaced by an artificial intraocular lens (IOL). Postoperative healing processes can cause a displacement of the IOL, which further leads to the fact that the quality of vision is deteriorated. Studies have shown that the imaging quality of high sophisticated IOL designs is more sensitive to lens displacements than simpler designs. The effects of IOL displacements are not well represented and tested within the current IOL test standard ISO 11979-2. This fact leads to the necessity to develope new test standards for novel and more sophisticated IOL designs. In this paper we present an improved model eye, which extends the current standard in three main aspects: First, the eye-model is very close to the physiology of the human eye. Second, electromechanic drives allow an automatic and precise simulation of postoperative lens tilts and decentrations, and finally in addition to standard conform MTF analysis, in the proposed setup also wavefront aberrations are measured. The latter reveals specific image aberrations caused by lens displacements. The model eye allows to objectively analyze the displacement tolerance of various IOL designs. The functionality of this novel setup is tested by measuring a spherical and an aspheric IOL design. Additionally, for comparison, IOLs that were already investigated with a previous version of the presented model eye are used for analysis. Measurements results reveal improvements compared to the previous version of the model eye and a functional prototype for wavefront measurement.

  10. Clinical outcomes using standard phacoemulsification and femtosecond laser-assisted surgery with toric intraocular lenses

    Science.gov (United States)

    Espaillat, Arnaldo; Pérez, Obniel; Potvin, Richard

    2016-01-01

    Purpose To compare the 1-month and 1-year results of toric intraocular lens (IOL) implantation with standard (manual) phacoemulsification vs femtosecond laser-assisted surgery. Patients and methods Refractive data, visual acuity data, and ocular aberration measured with a wavefront aberrometer were collected for two groups of patients from one site. The first group had standard phacoemulsification, while the second group had femtosecond laser-assisted surgery, and both groups were implanted with toric IOLs, either monofocal or multifocal. Differences in visual acuity, refractive outcomes, and higher order aberrations – total, corneal, and internal – were evaluated at 1 month and 1 year postoperatively. Results Toric IOLs were implanted in 62 eyes using standard phacoemulsification and 53 eyes using femtosecond laser-assisted surgery. Uncorrected visual acuity and best-spectacle-corrected visual acuity at 1 month and 1 year were not statistically significantly different between the groups (P>0.05) nor was the mean cylinder or mean spherical equivalent refraction (P>0.12). Total ocular higher order aberrations were significantly different between the groups (P<0.05), but absolute differences appeared to be the same. Internal vertical coma was significantly lower in the femto group at 1 year (P=0.03). Differences in aberrations did not correlate with corrected or uncorrected visual acuity. Conclusion Patients who underwent uncomplicated lens surgery with toric IOLs in both the groups had comparable refractive outcomes in terms of visual acuity and residual refraction at 1 year. The femto group had significantly lower internal vertical coma at 1 year. PMID:27099462

  11. Comparison Between Digital and Manual Marking for Toric Intraocular Lenses: A Randomized Trial.

    Science.gov (United States)

    Elhofi, Abdel Hamid; Helaly, Hany Ahmed

    2015-09-01

    To compare the clinical outcome of digital and manual marking for toric intraocular lens (IOL) alignment. This is a prospective clinical study that included 60 eyes of 60 patients undergoing cataract surgery with coexisting corneal astigmatism more than 1 diopter (D). The eyes were randomly assigned to either digital image guidance using VERION digital marker (Alcon Laboratories, Ft. Worth, TX) or manual slitlamp-assisted preoperative marking using pendulum-attached marker. Tecnis toric IOL (Abbott Medical Optics, Inc, Santa Ana, CA) was implanted in all cases. The mean postoperative uncorrected distance visual acuity (UCDVA) for the digital-marking group was 0.12 + 0.12 logMAR, and for the manual-marking group was 0.18 + 0.14 logMAR (P = 0.104). The mean deviation from targeted induced astigmatism (TIA) for the first group was 0.10 + 0.08 D and for the second group was 0.20 + 0.14 D (P = 0.001). The mean postoperative toric IOL misalignment measured by the slitlamp was 2.4° + 1.96° for the first group and was 4.33° + 2.72° for the second group (P = 0.003). Accurate alignment of the toric IOL is important to achieve the desired astigmatism correction. VERION system has the advantage of preoperative planning and intraoperative digital guidance of the toric IOL alignment. The use of VERION system resulted in less postoperative deviation from TIA and showed less postoperative toric IOL misalignment than using manual-marking technique. PMID:26402830

  12. Materials for intraocular lenses enabling photo-controlled tuning of focal length in vivo

    Science.gov (United States)

    Träger, Jens; Heinzer, Jasmin; Kim, Hee-Cheol; Hampp, Norbert

    2007-07-01

    Typical postoperative complications in cataract surgery are that refractive power and curvature of the implanted intraocular lens (IOL) do not have optimum values, requiring the patient to wear viewing aids. This is mainly because biometric data relevant for calculation of the IOL's shape cannot be determined with the required precision. Hence, there is a need for methods to tune the focal length postoperatively in a non-invasive manner. We have developed polymers where we can induce a change in refractive index by linking or cleaving bonds between a su.ciently large number of side groups of the polymer main chain in a photoinduced cycloaddition or cycloreversion reaction, respectively. These photoreactions lead to a change in refractive index great enough to be interesting for the concept of in vivo tunable IOL's. The photochemical reaction can be triggered by a two-photon process (TPA) using a pulsed laser system, i.e. the energy required for bond breaking is provided by two photons in the visible range. This is important because light in the UV cannot induce undesired changes of the refractive index owing to the strong UV-absorption of the cornea. Undesired changes due to light in the visible range of the spectrum are unlikely to happen because photon density of sun light is much too low for TPA. Due to the excellent spatial resolution that can be achieved with two-photon processes one cannot only modify the refractive index of the entire lens but also selectively in well defined areas enabling to correct for aberrations such as astigmatism. Here, we present new polymers that do not only exhibit a photo induced change of refractive index great enough to induce a change of focal length of more than two diopters in a standard IOL. These new polymers have also significantly improved material properties with respect to the fabrication of the IOL and the TPA-sensitivities and the light energy required to induce the refractive index change.

  13. Experimental study of aberration characteristics changing in case of intraocular lenses decentration

    Directory of Open Access Journals (Sweden)

    D.G. Zhaboiedov

    2014-01-01

    Full Text Available Nowadays the creation of high functional vision in intraocular correction which depends much on the optical properties of implanted IOL is of great importance. So far as even after an impeccably performed operation an IOL decentration occurs that inevitably induces aberrations which reduce the vision of a pseudophakic eye, it is important to use IOL models that are least sensitive to decentration. Purpose. To identify IOL models that are less sensitive to decentration using an artificial model of eye optical system. Material and methods. The experimental study of aberration properties of different IOL models TECNIS®, SA60AT, SN60WF, SL-907 «CentriX DZ» has been conducted on an original model. Results. At first the aberrometry of the eye model was performed without IOL, later an investigated IOL was placed into the eye model and centered by localization of mirror images of LEDs centering. Artificially created IOL decentration along the X-axis had ±0.5mm and ±1.0mm values, IOL angular rotations around the vertical axis were ±4° and ±8°. Decentration of all IOL models as well as its rotation around the vertical axis caused the change in the aberrations amplitude. The study showed that the SL-907 «CentriX DZ» IOL model is less sensitive to any IOL decentration and rotation (tilt, the TECNIS® and SN60WF models are more sensitive. The SA60AT IOL is the most sensitive to the decentr ation and rotation. Conclusions. Thus, the IOL decentration in the range of ±1mm and rotation angles of ±8 degrees cause an increase in the amplitude of the aberration modes, equal values of IOL decentration entail unequal changes in the values of aberrations between different IOL models. It has been found that the SL-907 «CentriX DZ» IOL model is less sensitive to decentration, rotation and tilt, that allows its use in cases with a high risk of its displacement in the postoperative period.

  14. Primary and secondary implantation of scleral-fixated posterior chamber intraocular lenses in adult patients

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    Zuleyha Yalniz-Akkaya

    2014-01-01

    Conclusion: Both primary and secondary scleral-fixated PCIOL implantations can provide favorable visual outcomes with lower complication rates. An important consideration is the appropriate timing for scleral fixation, taking into account the patient′s characteristics and the course of the operation.

  15. 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.

  16. Evaluation of actual retinal images produced by misaligned aspheric intraocular lenses in a model eye

    Directory of Open Access Journals (Sweden)

    Fujikado T

    2014-11-01

    Full Text Available Takashi Fujikado,1 Makoto Saika2 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan; 2Research and Development Department of Topcon Corporation, Tokyo, Japan Purpose: To examine the effect of misalignment (decentration and tilt of intraocular lenses (IOLs on retinal image quality using a water-immersed model eye with corneal spherical aberration adjusted to the values found in normal human eyes (spherical aberration 0.25 µm; pupil diameter 6 mm.Methods: Three types of IOL holders were prepared. The first was without decentration or tilt, the second had a decentration of 0.5 mm, and the third had a tilt of 5.0°. One spherical IOL and three aspherical IOLs, each with a power of +20 D, were set in the holders and their optical properties (wave front aberration, defocused modulation transfer function, defocused point spread function, and Landolt ring simulations were compared.Results: Coma aberrations generated by misaligned IOLs were related to the spherical aberration corrective power of the IOLs. Landolt ring simulations show that the depth of focus increased as spherical aberration increased and that the retinal image quality was degraded by increases in coma aberration.Conclusion: Coma aberration was generated by IOLs with a large degree of spherical aberration correction, leading to reduced retinal image quality when the IOL was misaligned. This suggests that, in a clinical setting, the quality of vision might be improved by reducing the degree of coma aberration using IOLs that retain, or minimally correct, spherical aberration. Keywords: coma aberration, decentration, misalignment, spherical aberration, tilt

  17. Trans-scleral Fixation of Posterior Chamber Intraocular Lens Combined with Vitreoretinal Surgery

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    Amir Khosro Ghaseminejad

    2008-12-01

    Full Text Available

    PURPOSE: To report the outcomes of trans-scleral fixation of posterior chamber intraocular lens (PCIOL combined with complete vitrectomy and prophylactic band placement. METHODS: Hospital records of 18 patients who underwent the procedure were reviewed. Indications for vitreoretinal surgery included previous penetrating ocular trauma, complicated cataract surgery and vitreous incarceration, and chronic cystoid macular edema. All patients had iris and angle damage with inadequate lens capsular support. Age, sex, surgical technique, follow up duration and pre- and postoperative best corrected visual acuity (BCVA were evaluated. RESULTS: Overall 18 eyes of 18 patients (14 men and 4 women with mean age of 34.8±23 (range 5-76 years were operated. Mean follow up duration was 36±32.4 (range 6-96 months. Of the 18 operated eyes 7 were aphakic, 6 had complete IOL dislocation into the vitreous cavity, 4 had subluxated cataractous lens and one had a subluxated IOL. The number of eyes with BCVA ? 20/40 increased from 3 (16.7% preoperatively to 9 (50% postoperatively (P < 0.01. Postoperative complications were encountered in 9 eyes and included uveitis, vitreous hemorrhage, repeat IOL dislocation and retinal detachment. CONCLUSION: In the absence of adequate capsular support, trans-scleral fixation of a PCIOL combined with

  18. Polymers for refractive index change in intraocular lenses: a novel approach for photoinduced tuning of focal length

    Science.gov (United States)

    Träger, Jens; Kim, Hee-Cheol; Hampp, Norbert

    2006-02-01

    Before an intraocular lens (IOL) is implanted during cataract surgery, biometric data of the patient's eye have to be determined to calculate the thickness and shape of the IOL. In particular the postoperative anterior chamber depth is an important parameter to predict the correct shape of the IOL. This value, however, cannot be measured without significant uncertainities. We present a solution to this problem, describe novel polymers suitable for IOLs which refractive indices can be changed non-invasively in a photo-induced process. The focal length can be modified by about 2 D, which is sufficient to achive ideal acuteness of vision for almost all patients with implanted IOLs. The change in refractive index is accomplished by linking or cleaving bonds between a sufficiently large number of side groups of the polymer main chain in a photoinduced cyloaddition or cycloreversion, respectively. The photochemical reaction can also be triggered by a two-photon process (TPA) using a pulsed laser system, i.e. the energy required for bond breaking is provided by two photons in the visible range. Light in the UV as well as the visible range of the spectrum cannot induce undesired changes of the refractive index owing to the strong UV-absorption of the cornea and photon densities much too low for TPA, respectively. Due to the excellent spatial resolution that can be achieved with two-photon processes not only modification of the refractive index of the entire lens but also selectively in well defined areas is possible enabling the correction for aberrations such as astigmatism.

  19. Successful toric intraocular lens implantation in a patient with induced cataract and astigmatism after posterior chamber toric phakic intraocular lens implantation: a case report

    OpenAIRE

    Kamiya Kazutaka; Nakamura Akio; Miyake Hideyuki; Nishimoto Hiroyuki; Shimizu Kimiya

    2012-01-01

    Abstract Introduction We report the case of a patient in whom simultaneous toric phakic intraocular lens removal and phacoemulsification with toric intraocular lens implantation were beneficial for reducing pre-existing astigmatism and acquiring good visual outcomes in eyes with implantable collamer lens-induced cataract and astigmatism. Case presentation A 53-year-old woman had undergone toric implantable collamer lens implantation three years earlier. After informed consent was obtained, we...

  20. Long-term results of extracapsular cataract extraction and posterior chamber intraocular lens insertion in Nepal.

    OpenAIRE

    Ruit, S; Robin, A L; Pokhrel, R. P.; Sharma, A.; DeFaller, J; Maguire, P T

    1991-01-01

    We performed a prospective study evaluating the 2-year success rate of extracapsular cataract surgery and posterior chamber IOL insertion performed in 610 eyes by an experienced surgeon in the Nepal Eye Hospital, Kathmandu, Nepal. All patients were followed for 2 years. All eyes underwent manual irrigation and aspiration of cortical materials with the insertion of a modified J-loop posterior chamber IOL. Almost one half of eyes had final uncorrected visual acuities of 20/50 or better. Devasta...

  1. Mechanistic modeling of ophthalmic drug delivery to the anterior chamber by eye drops and contact lenses.

    Science.gov (United States)

    Gause, Samuel; Hsu, Kuan-Hui; Shafor, Chancellor; Dixon, Phillip; Powell, Kristin Conrad; Chauhan, Anuj

    2016-07-01

    Ophthalmic drug for the anterior chamber diseases are delivered into tears by either eye drops or by extended release devices placed in the eyes. The instilled drug exits the eye through various routes including tear drainage into the nose through the canaliculi and transport across various ocular membranes. Understanding the mechanisms relevant to each route can be useful in predicting the dependency of ocular bioavailability on various formulation parameters, such as drug concentration, salinity, viscosity, etc. Mathematical modeling has been developed for each of the routes and validated by comparison with experiments. The individual models can be combined into a system model to predict the fraction of the instilled drug that reaches the target. This review summarizes the individual models for the transport of drugs across the cornea and conjunctiva and the canaliculi tear drainage. It also summarizes the combined tear dynamics model that can predict the ocular bioavailability of drugs instilled as eye drops. The predictions from the individual models and the combined model are in good agreement with experimental data. Both experiments and models predict that the corneal bioavailability for drugs delivered through eye drops is less than 5% due to the small area of the cornea in comparison to the conjunctiva, and the rapid clearance of the instilled solution by tear drainage. A contact lens is a natural choice for delivering drugs to the cornea due to the placement of the contact in the immediate vicinity of the cornea. The drug released by the contact towards the cornea surface is trapped in the post lens tear film for extended duration of at least 30min allowing transport of a large portion into the cornea. The model predictions backed by in vivo animal and clinical data show that the bioavailability increases to about 50% with contact lenses. This realization has encouraged considerable research towards delivering ocular drugs by contact lenses. Commercial

  2. Successful toric intraocular lens implantation in a patient with induced cataract and astigmatism after posterior chamber toric phakic intraocular lens implantation: a case report

    Directory of Open Access Journals (Sweden)

    Kamiya Kazutaka

    2012-04-01

    Full Text Available Abstract Introduction We report the case of a patient in whom simultaneous toric phakic intraocular lens removal and phacoemulsification with toric intraocular lens implantation were beneficial for reducing pre-existing astigmatism and acquiring good visual outcomes in eyes with implantable collamer lens-induced cataract and astigmatism. Case presentation A 53-year-old woman had undergone toric implantable collamer lens implantation three years earlier. After informed consent was obtained, we performed simultaneous toric implantable collamer lens removal and phacoemulsification with toric intraocular lens implantation. Preoperatively, the manifest refraction was 0, -0.5 × 15, with an uncorrected visual acuity of 0.7 and a best spectacle-corrected visual acuity of 0.8. Postoperatively, the manifest refraction was improved to 0, -0.5 × 180, with an uncorrected visual acuity of 1.2 and a best spectacle-corrected visual acuity of 1.5. No vision-threatening complications were observed. Conclusion Toric intraocular lens implantation may be a good surgical option for the correction of spherical and cylindrical errors in eyes with implantable collamer lens-induced cataract and astigmatism.

  3. 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

    Science.gov (United States)

    Gundersen, Kjell Gunnar; Potvin, Rick

    2016-01-01

    Purpose 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 (Pdashboard or grocery shelf. VA was similar between groups at viewing distances from 60 to 40 cm, corresponding to computer or reading distance. PMID:27274184

  4. 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

    Directory of Open Access Journals (Sweden)

    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

  5. Corneal Endothelial Cell Changes Due to Combined Phacoemulsification-Posterior Chamber Intraocular Lens Implantation and Transpupillary Silicone Oil Removal

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    Mehmet Hanifi Alp

    2014-12-01

    Full Text Available Objectives: The aim of this study was to evaluate the effects of combined phacoemulsification-posterior chamber intraocular lens (PCIOL implantation and removal of transpupillary silicone oil on the corneal endothelial cell layer. Materials and Methods: In this study, we included seven eyes of 7 patients who had intravitreal hemorrhage resulting from retinal detachment or tractional retinal detachment due to proliferative diabetic retinopathy and who underwent pars plana vitrectomy and silicone oil injection. Complicated cataract developed, and phacoemulsification-PC-IOL implantation combined with transpupillary silicon oil removal were performed. Preoperative and postoperative corneal endothelial cell count values were taken by Topcon SP-2000P automatic non-contact specular microscopy and were assessed by IMAGEnet 2000 Endothelial Cell Analysis. The results were compared with the findings in the literature. Results: The mean endothelial cell density (ECD was 2461 cell/mm2 preoperatively. The silicone oil removal was performed after an average of 10±3.5 months (range 5-14 months, and then endothelial cells were counted after a mean of 17±21.2 months (range 1-49 months of the combined surgery. The mean ECD was determined as 1906 cell/mm2 postoperatively. While mean endothelial cell loss was found to be 32% in two patients with diabetes mellitus, five non-diabetic patients had 19% cell loss. Corneal decompensation was not observed in any patient during the follow-up period. Conclusion: After combined phacoemulsification-PC-IOL implantation and transpupillary silicone oil removal, significant reduction in endothelial cells was observed. We detected that this reduction was greater in diabetics. (Turk J Ophthalmol 2014; 44: 424-7

  6. Audit of exracapsular cataract extraction with posterior chamber intraocular lens implantation in a tertiary eye care center in Ethiopia.

    Science.gov (United States)

    Tilahun, Yonas; Sisay, Alemayehu

    2006-01-01

    A retrospective audit of records of 370 eyes of 315 patients for whom extracapsular cataract extraction with posterior chamber intraocular lens implantation (ECCE-PC IOL) was performed between 1998 and 1999 was made to determine postoperative visual outcome and complications. One hundred and ninety three patients were males and one hundred and seventy seven were females making a male to female ratio of 1:0.9. At two months postoperatively 82 (30.4%) of eyes had uncorrected visual acuity of 6/18 or better; while 176 (53.7%) of eyes attained an uncorrected visual acuity between 6/18 and 6/60, and 31 (11.5%) had visual acuity between 3/60 and 6/60. 340 of 358 (94.9%) had a preoperative visual acuity of < 3/60. As a result of the surgery, the percentage of blind eyes dropped from 94.9% to 4.4%. The commonest intra operative and early postoperative complications encountered were posterior capsular tear with vitreous loss (5.7%) and striate keratopathy (11.1%) respectively. Posterior capsular opacity was documented in 17 (4.6%) eyes as a late postoperative complication. Routine biometry, to calculate Intra ocular Lens (IOL) power was not done and this was the major limitation of the study. In conclusion, the study increases awareness of cataract surgery outcomes and provides a feedback to achieve better results both in terms of quality and quantity in cataract surgery. Further study with biometric measurement is recommended. PMID:17447364

  7. Retinal image quality with the different types of intraocular lenses including new idea of the hybrid IOLs

    Science.gov (United States)

    Siedlecki, D.; Zając, M.; Nowak, J.

    2007-07-01

    Cataract is one of the most frequent reasons of blindness all around the world. Its treatment relies on removing the pathologically altered crystalline lens and replacing it with an artificial intraocular lens (IOL). There exists plenty of types of such implants, which differ in the optical materials and designs (shapes). However one of the important features, which is rather overlooked in the development of the intraocular implants is the chromatic aberration and its influence on the retinal image quality. In this study authors try to estimate the influence of the design and optical material of the implant on the retinal image quality in the polychromatic light, taking into consideration several exemplary types of IOLs which are commercially available. Authors also propose the partially achromatized hybrid IOLs, the longitudinal chromatic aberration (LCA)of which reduces the total LCA of the phakic eye to the level of a healthy eye's LCA. Several image characteristics, as the polychromatic Point Spread Function (PSF) and the Modulation Transfer Function (MTF) and the polychromatic encircled energy are estimated. The results of the simulations show the significance of the partial chromatic aberration correction.

  8. Late opacification of a hydrophilic acrylic intraocular lens

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    Al-Bdour Muawyah

    2008-01-01

    Full Text Available Cataract extraction and intraocular lens implantation is considered to be a safe procedure in most cases. However, the new advances in the surgical technique namely phacoemulsification and hence the increased use of foldable intraocular lenses have given rise to new complications including late opacification of intraocular lenses. In this case we report late opacification of a foldable hydrophilic acrylic intraocular lens and the surgical technique for its exchange.

  9. To guard against mistakes in selection of intraocular lenses%警惕人工晶状体选择的误区

    Institute of Scientific and Technical Information of China (English)

    何守志

    2008-01-01

    各种新型人工晶状体面世,为满足临床不同需求提供了更多的选择机会,对于推动白内障手术更趋完美起到了积极作用.但在进行人工晶状体选择时,尚存在很多误区.比如"贵的就是好的","新的就一定是完美的"等;还有重使用轻总结,片面夸大某些特殊功能等倾向.在人工晶状体选择时,如何充分考虑患者的需求,处理好特殊需求和基本需求之间的关系,避免盲目性,把最大的受益提供给患者,是我们共同面临的问题.%Development of different kinds of new intraocular lenses(IOL)provide more selections to meet various clinical requirements,which may plays an active role in making cataract surgery more perfectible.But there are many misunderstandings about how to select the proper IOL.For example,"the expensive one is the best one","new product is absolutely perfect",and SO on.Some surgeons prefer more practice and ignore the summary of the experiences.Someone unilaterally exaggerates some special function of IOL When selecting the IOL,it is a common challenge for us to fully consider the patients needs,and properly manage the relationship between the basic need and special need,and to avoid fanaticism,and provide the best benefits to the patients.

  10. Bilateral Primary Intraocular Lymphoma

    OpenAIRE

    Mehrdad Karimi; Masoud Soheilian; Mozhgan Rezaei Kanavi

    2011-01-01

    Purpose: To report a case of bilateral primary intraocular lymphoma. Case report: A 33-year-old man presented with bilateral blurred vision since two years ago. Examination revealed large keratic precipitates, anterior chamber reaction, posterior subcapsular cataracts, and vitreous infiltration. After a short trial of topical and periocular steroids, diagnostic 25-gauge pars plana vitrectomy was performed and cytologic evaluation of the aspirate confirmed a diagnosis of intraocular lympho...

  11. Bilateral Primary Intraocular Lymphoma

    Directory of Open Access Journals (Sweden)

    Mehrdad Karimi

    2011-01-01

    Full Text Available Purpose: To report a case of bilateral primary intraocular lymphoma. Case report: A 33-year-old man presented with bilateral blurred vision since two years ago. Examination revealed large keratic precipitates, anterior chamber reaction, posterior subcapsular cataracts, and vitreous infiltration. After a short trial of topical and periocular steroids, diagnostic 25-gauge pars plana vitrectomy was performed and cytologic evaluation of the aspirate confirmed a diagnosis of intraocular lymphoma. The patient was subsequently managed with intravitreal methotrexate in both eyes and responded favorably. Central nervous system workup for lymphoma was negative. Conclusion: Primary intraocular lymphoma should be considered in young adults suffering from chronic recalcitrant panuveitis.

  12. Simulation of airbag impact on eyes with different axial lengths after transsclerally fixated posterior chamber intraocular lens by using finite element analysis

    Directory of Open Access Journals (Sweden)

    Huang J

    2015-02-01

    Full Text Available Jane Huang,1 Eiichi Uchio,1 Satoru Goto2 1Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, 2Nihon ESI KK Technical Division, Tokyo, Japan Purpose: To determine the biomechanical response of an impacting airbag on eyes with different axial lengths with transsclerally fixated posterior chamber intraocular lens (PC IOL.Materials and methods: Simulations in a model human eye were performed with a computer using a finite element analysis program created by Nihon, ESI Group. The airbag was set to be deployed at five different velocities and to impact on eyes with three different axial lengths. These eyes were set to have transsclerally fixated PC IOL by a 10-0 polypropylene possessing a tensile force limit of 0.16 N according to the United States Pharmacopeia XXII.Results: The corneoscleral opening was observed at a speed of 40 m/second or more in all model eyes. Eyes with the longest axial length of 25.85 mm had the greatest extent of deformity at any given impact velocity. The impact force exceeded the tensile force of 10-0 polypropylene at an impact velocity of 60 m/second in all eyes, causing breakage of the suture. Conclusion: Eyes with transsclerally fixated PC IOL could rupture from airbag impact at high velocities. Eyes with long axial lengths experienced a greater deformity upon airbag impact due to a thinner eye wall. Further basic research on the biomechanical response for assessing eye injuries could help in developing a better airbag and in the further understanding of ocular traumas. Keywords: airbag, ocular trauma, computer simulation, transsclerally fixated posterior chamber intraocular lens, finite element analysis

  13. Optical bench performance of AcrySof® IQ ReSTOR®, AT LISA® tri, and FineVision® intraocular lenses

    Directory of Open Access Journals (Sweden)

    Carson D

    2014-10-01

    Full Text Available Daniel Carson,1 Warren E Hill,2 Xin Hong,1 Mutlu Karakelle1 1Alcon Research, Ltd., Fort Worth, TX, USA; 2East Valley Ophthalmology, Mesa, AZ, USA Purpose: To compare the resolution and optical quality of the ReSTOR® +3.0 D and ReSTOR +2.5 D multifocal intraocular lenses (IOLs with the AT LISA® tri and FineVision® trifocal IOLs.Methods: Resolution, image quality, and photic phenomena were evaluated in the AcrySof® IQ ReSTOR +3.0 D and +2.5 D multifocal IOLs and compared with the AT LISA tri 839MP and FineVision Micro F12 trifocal IOLs, using a Badal optometer and a Snellen visual acuity chart. Simulated headlight images were obtained using a modulation transfer function (MTF bench and a 50 µm pinhole target. MTF values, using vertical and horizontal slits, were determined at far, intermediate, and near distances. Results: Resolution at 20/40 Snellen visual acuity equivalence was attainable over nearly the entire viewing distance range with the AT LISA tri and FineVision IOLs, but background shadows were more prominent with the AT LISA tri and FineVision IOLs than with the ReSTOR IOLs. Distance MTF peaks at 20/20 Snellen–equivalent spatial frequency were greatest for ReSTOR +2.5 D and ReSTOR +3.0 D IOLs. The near MTF peak occurred at 53 cm with ReSTOR +2.5 D and had a 20/20 Snellen–equivalent value that was lower than the near peaks of the other models but higher than the intermediate foci of the trifocal IOLs. Conclusion: AT LISA tri and FineVision trifocal IOLs achieved a useful third focus for intermediate vision but were associated with increased background halos and reduced distance visual quality compared with ReSTOR +2.5 D and +3.0 D multifocal IOLs. Keywords: multifocal, trifocal, modulation transfer function, Badal image, visual acuity, resolution

  14. Phakic anterior chamber intraocular lens (Verisyse™) implantation in children for treatment of severe ansiometropia myopia and amblyopia: Six-month pilot clincial trial and review of literature

    OpenAIRE

    Pirouzian, Amir

    2009-01-01

    Amir Pirouzian1,3, Kenneth C Ip2, Henry S O’Halloran31The Permanente Medical Group, Santa Clara, CA, USA; 2The Permanente Medical Group, San Francisco, CA, USA; 3Rady’s Children’s Hospital of San Diego, San Diego, CA, USAPurpose: The current study aims to evaluate both safety and efficacy of Verisyse™ (AMO, Irvine, CA) phakic anterior chamber intraocular lens (IOL) in the reduction of clinically significant (>-8 D) myopic anisometropia in childre...

  15. SURGICAL OUTCOME OF TRIPLE PROCEDURE AS PENETRATING KERATOPLASTY WITH EXTRACAPSULAR CATARACT EXTRACTION WITH POSTERIOR CHAMBER INTRAOCULAR LENS IMPLANTATION IN PATIENTS WITH BOTH CENTRAL CORNEAL OPACITY AND ADVANCED CATARACT AT RURAL SET UP

    OpenAIRE

    Shubhangi Nigwekar, Kishor Badhe, Neeta Misra, Surekha Bangal

    2015-01-01

    Purpose: To study the surgical outcome of triple procedure as penetrating keratoplasty (PKP) with conventional extra capsular cataract extraction (ECCE) with posterior chamber intraocular lens (PCIOL) implantation in patients with both central corneal opacity and advanced cataract at rural set up. Introduction: When corneal opacity and cataract present together then well-established and effective triple procedure is indicated. Prognosis for a clear graft is good in triple, as graft endothe...

  16. 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

    Directory of Open Access Journals (Sweden)

    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

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

    OpenAIRE

    Gupta, Isha; Oakey, Zack; Ahmed, Faisal; Ambati, Balamurali K

    2014-01-01

    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 Implant...

  18. 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

  19. 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

  20. Visual and optical performance of diffractive multifocal intraocular lenses with different haptic designs: 6 month follow-up

    Directory of Open Access Journals (Sweden)

    Wang M

    2014-05-01

    Full Text Available Mengmeng Wang,1,* Christine Carole C Corpuz,1 Megumi Fujiwara,1 Minoru Tomita1,2,*1Shinagawa LASIK Center, Tokyo, Japan; 2Department of Ophthalmology, Wenzhou Medical College, Wenzhou, People’s Republic of China*These authors contributed equally to this workPurpose: To evaluate and compare the visual acuity outcomes and optical performances of eyes implanted with two diffractive multifocal intraocular lens (IOL models with either a plate haptic design or a modified-C design.Methods: This retrospective study comprised cataract patients who were implanted with either a plate haptic multifocal IOL model (AcrivaUD Reviol BB MFM 611 [VSY Biotechnology, Amsterdam, the Netherlands], group 1 or a modified-C haptic multifocal IOL model ( AcrivaUD Reviol BB MF 613 [VSY Biotechnology, Amsterdam, the Netherlands], group 2 between June 2012 and May 2013. The 6 month postoperative visual acuity, refraction, defocus curve, contrast sensitivity, and wave-front aberration were evaluated and compared between these eyes, using different IOL models.Results: One hundred fifty-eight eyes of 107 patients were included in this study. Significant improvement in visual acuities and refraction was found in both groups after cataract surgery (P<0.01. The visual acuity and contrast sensitivity were statistically better in group 1 than in group 2 (P<0.01. No statistically significant difference in the corneal higher-order aberrations was found between the two groups (P>0.05. However, the ocular higher-order aberrations in group 2 were significantly greater than in group 1 (P<0.05.Conclusion: At 6 months postoperatively, both AcrivaUD Reviol BB MFM 611 IOL and AcrivaUD Reviol BB MF 613 IOL achieved excellent visual and refractive outcomes. The multifocal IOL model with plate haptic design resulted in better optical performances than that with the modified-C haptic design.Keywords: AcrivaUD, VSY, plate haptic, modified-C haptic, multifocal

  1. The measurement of intraocular pressure by non-contact tonometer through bandage contact lenses%应用非接触性眼压计经绷带型角膜接触镜的眼压测量

    Institute of Scientific and Technical Information of China (English)

    陈约洁; 王爱孙; 郑钦象

    2015-01-01

    Objective To evaluate the feasibility and accuracy of the measurement of inttrocular pressure (IOP) by non-contact tonometer (NCT) through bandage contact lenses.Methods IOPs were measured by (NCT) in 42 eyes of 42 patients with and without bandage contact lenses for three times each to get the averages.The values of with and without bandage contact lenses were compared.The correlation of the measurements with and without bandage contact lenses was analyzed.Results The measurement with bandage contact lenses appeared greater than the one without bandage contact lenses (15.26±6.81mmHg vs 13.05±6.16mmHg, P <0.05).The difference of IOPs was 2.21±2.04mmHg, with a maximum of 8mmHg, a minimum of-1.5mmHg, and 95% confidence interval (1.58-2.85mmHg).The measurements with bandage contact lenses significantly correlated with the measurements without bandage contact lenses (r =0.96, P <0.01), while the differences of IOPs did not significantly correlated with the native measurement (r =0.17, P =0.28).Conclusions The measurement of intraocular pressure by non-contact tonometer through bandage contact lens is feasible, so it's unnecessary to remove lenses frequently before the procedures, lest the corneas will be injured once more.However, it should be noted that IOPs through bandage contact lenses may be overestimated.%目的 评价非接触性眼压计(non-contact tonometry,NCT)经绷带型角膜接触镜测量眼压的可行性和准确性.方法 选取2013年11月至2014年6月在温州医科大学眼视光医院需要配戴绷带型角膜接触镜的角膜病、角膜外伤及角膜术后患者42例,共42只患眼.应用NCT分别在患者配戴角膜接触镜前、后测量眼压3次取平均值,比较配戴角膜接触镜前后眼压测值,并进行相关分析以判断角膜接触镜对眼压测量的影响.结果 42例患者配戴前的眼压为(13.05±6.16) mmHg,配戴后的眼压为(15.26±6.81) mmHg,差异有统计学意义(P<0.05),

  2. Pupillary block glaucoma following implantation of a posterior chamber pseudophakos in the anterior chamber.

    Directory of Open Access Journals (Sweden)

    Mandal Anil

    2002-01-01

    Full Text Available Pupillary block glaucoma is a common complication of cataract surgery, especially following anterior chamber intraocular lens implantation. We report a case of pupillary block glaucoma with a posterior chamber IOL that was implanted in the anterior chamber following a complicated extracapsular cataract extraction. The case was successfully managed by explantation of the posterior chamber lens, anterior vitrectomy, peripheral iridectomy and secondary anterior chamber intraocular lens implantation. The intraocular pressure was controlled with a single topical antiglaucoma medication.

  3. Patient-reported benefit of ReSTOR® multi-focal intraocular lenses after cataract surgery: Results of Principal Component Analysis on clinical trial data

    Directory of Open Access Journals (Sweden)

    Viala Muriel

    2008-01-01

    Full Text Available Abstract Background Restoration of functional distance and near vision independently of additional correction remains a goal for cataract surgery. ReSTOR®, a new multi-focal intraocular lens (IOL addresses this issue with an improvement in both distance and near vision, often without need for glasses. This analysis attempted to discuss the patient-reported benefit of ReSTOR® using a full but organised representation of data. Methods Two non-randomised, open-label clinical trials conducted in Europe and the United-States were conducted to compare the efficacy of ReSTOR® to AcrySof® mono-focal IOLs. A total of 710 patients in need of bilateral cataract extraction were included in the pooled study. The TyPE, a patient questionnaire, was fully completed by 672 of them before and after each eye surgery. The TyPE, composed of 67 items measuring overall visual functioning in both conditions (with and without wearing glasses, evaluates limitations, troubles and satisfaction in distance and near vision. A principal component analysis (PCA of the TyPE questionnaire was performed on pooled data from baseline and post-surgery observations in order to fully represent the change in the TyPE data over time. ReSTOR® and mono-focal groups were used as illustrative variables. The coordinates of the first 2 factors were compared between visits and between IOLs (ReSTOR® vs. mono-focal, using paired t-tests and t-tests, respectively. Results The first factor of the PCA explained 55% of the variance and represented 'visual functioning and patient satisfaction'. The second factor explained 6% of the variance and was interpreted as 'independence from glasses'. An overall difference in factorial coordinates in both factors was seen between baseline and the first eye surgery, and between the first and the second eye surgery. No difference between ReSTOR® and mono-focal IOL groups was observed at baseline. After surgery, ReSTOR® treated-patients had higher

  4. A new radionuclear method for the measurement of the flow of intraocular fluid applying a paperstripe saturated with 22NaCl and a gamma-chamber

    International Nuclear Information System (INIS)

    The first results of this new method are reported. A paperstripe saturated with 22NaCl is put on the cornea and the change of scintillation is measured with a gamma-chamber. The non-invasive method may be of significance in the diagnosis of glaucoma and may be used for the evaluation of glaucoma treatment. (author)

  5. [Results of intraocular lens implantation in cataract complicated by medium and high myopia].

    Science.gov (United States)

    Plotnikova, Iu A; Chuprov, A D; Volkov, D V

    2001-01-01

    Results of surgical treatment of cataract complicated by medium and high myopia are analyzed. The main group consisted of 90 patients (96 eyes) subjected to extracapsular cataract extraction with implantation of posterior-chamber intraocular lenses and the reference group of 128 patients in whom cataract was extracted without implantation of artificial lens. The study included creation of a mathematical model of myopic eye with estimation of pressure fluctuations in various zones of the eye, developing during transposition of the vitreous during patient's movements (head movements, jumps, falling) and the damping effect of the lens in the ocular system. It was proven by mathematical calculations that transpositions of jelly fractions of the vitreous decreased by 70% in an eye with the lens in comparison with their transposition in aphakia. Clinical studies demonstrated the efficiency of intraocular correction of aphakia in high myopia: implantation of an intraocular lens decreases the risk of detachment of the retina during the postoperative period and helps attain the desired refraction. PMID:11765458

  6. Intraocular lymphoma after cardiac transplantation: Magnetic resonance imaging findings

    International Nuclear Information System (INIS)

    We report a case of intraocular lymphoma in a 65-year-old man, 15 months after cardiac transplantation. On Magnetic Resonance (MR) images, the iris and the anterior chamber of the right eye were found to be involved with an enhancing soft-tissue lesion. To our knowledge, this is the first case of post-transplantation intraocular lymphoma evaluated with MR imaging.

  7. Intraocular lymphoma after cardiac transplantation: Magnetic resonance imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yi Kyung; Kim, Hyung Jin; Woo, Kyung In; Kim, Yoon Duck [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2013-01-15

    We report a case of intraocular lymphoma in a 65-year-old man, 15 months after cardiac transplantation. On Magnetic Resonance (MR) images, the iris and the anterior chamber of the right eye were found to be involved with an enhancing soft-tissue lesion. To our knowledge, this is the first case of post-transplantation intraocular lymphoma evaluated with MR imaging.

  8. Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

    Directory of Open Access Journals (Sweden)

    Ladan Espandar

    2011-01-01

    Full Text Available Ladan Espandar1, Shameema Sikder2, Majid Moshirfar31Department of Ophthalmology, Tulane University, New Orleans, LA, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA; 3John A Moran Eye Center, University of Utah, Salt Lake City, UT, USAAbstract: Intraocular lens development is driven by higher patient expectations for ideal visual outcomes. The recently US Food and Drug Administration-approved Softec HD™ lens is an aspheric, hydrophilic acrylic intraocular lens (IOL. The hydrophilic design of the lens is optimized to address dysphotopsia while maintaining biocompatibility, optical clarity, resistance to damage, and resistance to biocontamination. Aspheric lenses decrease postoperative spherical aberration. The addition of the Softec lens provides clinicians with another option for IOL placement; however, randomized comparative studies of this lens to others already on the market remain to be completed.Keywords: hydrophilic acrylic intraocular lens, Softec HD intraocular lens, aspheric intraocular lens, IOL

  9. Experimental study for dynamic immunity after the implantion of posterior chamber intraocular lens in rabbit eyes%兔眼后房型人工晶体植入术后动态免疫的实验研究

    Institute of Scientific and Technical Information of China (English)

    杜耀武; 单季先; 刘英杰; 柴立辉

    2003-01-01

    目的:研究兔眼后房型人工晶体植入(Posterior chamber intraocular lens,PC-IOL)术后体液免疫反应(HI)的变化,探讨人工晶体与体液免疫反应变化及术后炎症反应的关系.方法:家兔48只,随机分为A、B 2组,每组24只.A组行右眼透明晶体超声乳化吸除及人工晶体植入,B组行右眼透明晶体超声乳化吸除.分别在术前及术后第7d、14d、21d、28d、35d采血测定IgG、IgM、CH50、C3、Circalating immune complex(CIC),并观察临床指征--睫状充血、房水浑浊程度的变化.结果:A、B 2组术后IgG、IgM、CIC均升高,2组间无显著性差异(P>0.05).CH50、C3均降低,2组间也无显著性差异(P>0.05).A组术后眼内反应明显较B组重,差异非常显著(P<0.01).结论:人工晶体(PMMA)具有较好的稳定性,眼内植入安全.术后早期眼内炎症主要是由人工晶体异物性刺激及手术机械性损伤引起,HI的变化可能与迟发性葡萄膜炎有关.

  10. SURGICAL OUTCOME OF TRIPLE PROCEDURE AS PENETRATING KERATOPLASTY WITH EXTRACAPSULAR CATARACT EXTRACTION WITH POSTERIOR CHAMBER INTRAOCULAR LENS IMPLANTATION IN PATIENTS WITH BOTH CENTRAL CORNEAL OPACITY AND ADVANCED CATARACT AT RURAL SET UP

    Directory of Open Access Journals (Sweden)

    Shubhangi Nigwekar, Kishor Badhe, Neeta Misra, Surekha Bangal

    2015-10-01

    Full Text Available Purpose: To study the surgical outcome of triple procedure as penetrating keratoplasty (PKP with conventional extra capsular cataract extraction (ECCE with posterior chamber intraocular lens (PCIOL implantation in patients with both central corneal opacity and advanced cataract at rural set up. Introduction: When corneal opacity and cataract present together then well-established and effective triple procedure is indicated. Prognosis for a clear graft is good in triple, as graft endothelium does not touch the hard nucleus which may occur in two steps or sequential surgery. It provides faster visual rehabilitation. Being single step procedure it reduces patient’s hospital stay, postoperative care and follows up visits. Methodology: In this hospital based observational , three years longitudinal study, we studied the surgical outcome of relatively rare one step triple procedure as PKP with conventional ECCE with PCIOL implantation in sulcus or in bag, in patients with both central corneal opacity and advanced cataract at rural set up. The outcome measures included graft clarity on slit lamp, postoperative unaided visual acuity with Snellen’s chart and the occurrence of postoperative complications after taking IEC permission and informed written consent in local language from study patients. Results: Out of 13 study patients mean age was 61.15yrs (Range50-80yrs. Follow up range was 9-34 months. At final follow up 9 patients (69.23% had clear grafts and 61.52% patients gained visual acuity >6/24. Graft failure was the most common post operative complication in 30.76% followed by Posterior capsular opacification (PCO in 15.38% patients which was treated well with YAG laser capsulotomy. Conclusion: Triple procedure gives good results in respect to graft clarity, unaided vision, and faster rehabilitation.

  11. Ophthalmic halo reduced lenses design

    Science.gov (United States)

    Limon, Ofer; Zalevsky, Zeev

    2015-05-01

    The halo effect is a very problematic visual artifact occurring in extended depth of focus or multi-focal ophthalmic lenses such as e.g. intra-ocular (after cataract surgery) or contact lenses when used in dark illumination conditions. This artifact is generated due to surface structures added on top of those lenses in order to increase their depth of focus or to realize multiple focal lengths. In this paper we present novel solution that can resolve this major problem of ophthalmic lenses. The proposed solution involves modification to the surface structure that realizes the extended depth of focus. Our solution is fabricated and numerically and experimentally validated also in preliminary in-vivo trials.

  12. Clinical Study on the Visual Quality of Eyes Implanted With AcrySof IQ Aspherical Intraocular Lenses%非球面AcrySof IQ人工晶状体植入术后视觉质量临床研究

    Institute of Scientific and Technical Information of China (English)

    陈迎迎; 谭少健; 梁皓; 刘彦斌

    2012-01-01

    目的 评价非球面人工晶状体(IOL)AcrySof IQ IOL植入术后年龄相关性白内障患者的视觉质量.方法 年龄相关性白内障患者42例55眼,按随机数字表法将患者分成两组.其中非球面人工晶体组24例(28眼),植入AcrySof IQ IOL;球面人工晶体组18例(27眼),植入AcrySof Natural IOL.术后随访3个月的裸眼视力(UCVA)、最佳矫正远视力(BCVA),不同亮度环境下的对比敏感度等.结果 手术后3个月非球面组UCVA为0.76±0.18,优于球面组的0.66±0.17,差异有统计学意义(P<0.05).非球面组BCVA为0.85±0.19,优于球面组的0.74±0.19,差异有统计学意义(P<0.05).两组球镜、柱镜差异无统计学意义(P>0.05).在明视觉条件下,非球面组在12.0 cpd、18.0 cpd的对比敏感度明显优于球面组(P<0.01).在暗视觉条件下非球面组所有空间频率的对比敏感度非球面组均优于球面组(P<0.05).非球面组眩光、光晕等的发生率均低于球面组(P<0.05).结论 白内障术后早期,非球面人工晶状体能够提供较好的术后裸眼视力、最佳矫正远视力、亮环境下高频对比敏感度和暗环境下的所有空间频率的对比敏感度,提示非球面人工晶状体能够提供较好的视觉质量.%Objective To evaluate the visual quality of eyes implanted with AcrySof IQ aspherical intraocular lenses( IOLs ). Methods Forty-two patients( 55 eyes ) with age-related cataracts were enrolled in the study, who were randomly divided into two groups according to random number table. Phacoemulsification and IOL implantation were applied to patients with aspherical IOLs( AcrySof IQ ) in 28 eyes and spherical IOLs( AcrySof Natural IOL ) in 27 eyes, respectively. All patients were followed up for 3 months. The examinations included uncorrected visual acuity ( UCVA ),best corrected visual acuityC BCVA ),contrast sensitivity( Functional Acuity Contrast Test ),and questionnaires were applied on the 3rd month after operation

  13. Comparação entre os resultados pós-operatórios de pacientes submetidos ao procedimento tríplice e transplante de córnea combinado a fixação secundária de lente intra-ocular Comparison between the postoperative results of triple procedure and combined penetrating keratoplasty/ transsclerally sutured posterior chamber lens implantation

    Directory of Open Access Journals (Sweden)

    Daniela Maggioni Pereira Leão

    2006-08-01

    Full Text Available OBJETIVO: Comparar os resultados pós-operatórios de 2 grupos de pacientes submetidos a transplante de córnea com técnicas e tempo cirúrgico diferentes, em relação à abordagem do cristalino e/ou lente intra-ocular. MÉTODOS: Neste estudo retrospectivo foram analisados 37 olhos de pacientes divididos em 2 grupos: extração de catarata, implante de lentes intra-oculares (LIO e transplante de córnea no mesmo tempo cirúrgico - grupo 1 (G1 e extração de catarata sem implante de lentes intra-oculares no primeiro tempo cirúrgico e fixação secundária de lentes intra-oculares associada a transplante de córnea no segundo tempo cirúrgico - grupo 2 (G2. As variáveis estudadas foram: acuidade visual, pressão intra-ocular (PIO, astigmatismo refracional, astigmatismo ceratométrico e complicações pós-operatórias. RESULTADOS: Foi observado melhora da acuidade visual nos 2 grupos (G1 pPURPOSE: To compare the outcomes of two surgical techniques of penetrating keratoplasty with different surgical time, regarding the crystalline and the intraocular lens. METHODS: This retrospective study included 37 patients' eyes divided into 2 groups: extracapsular cataract extraction, posterior chamber intraocular lens implantation and penetrating keratoplasty (Group 1, G1 and transscleral fixation of posterior chamber lens and penetrating keratoplasty (Group 2, G2. The following parameters were recorded: visual acuity, intraocular pressure, refractive astigmatism, complication and keratometric astigmatism. RESULTS: Visual acuity improved in the two groups (G1 p<0.001 and G2 p=0.008. In G2 a significant change for the worse of intraocular pressure outcome was observed when compared with the other group (p=0.014. Regarding refractive and keratometric astigmatism no significant differences between the groups were found. The follow-up was 11 months. CONCLUSION: The most important negative prognostic factor affecting visual acuity was the postkeratoplasty

  14. Determination of heparin on intraocular lens surfaces by ion chromatography.

    Science.gov (United States)

    Ander, B; Karlsson, A; Ohrlund, A

    2001-05-11

    A sensitive and selective method has been developed for the determination of heparin on heparin coated PMMA, poly(methyl methacrylate), intraocular lenses. Heparin was hydrolysed to glucosamine and glucuronic acid, and the content of glucosamine was determined using ion chromatography with pulsed amperometric detection. In order to verify that a complete hydrolysis was obtained for the heparin on the coated intraocular lenses, electron spectroscopy for chemical analysis (ESCA) was used for analysing traces of sulphur on the lens surfaces. The sensitivity of the method allows quantitative determination of 150 ng of heparin on one individual lens. The new method was compared to a standard spectrophotometric method, measuring the colour intensity of a heparin toluidine blue complex. Correlation between the methods was shown for samples prepared from PMMA lenses coated with different amounts of heparin. PMID:11403462

  15. 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.

  16. Accuracy of Intraocular Lens Power Formulas Involving 148 Eyes with Long Axial Lengths: A Retrospective Chart-Review Study

    OpenAIRE

    Chong Chen; Xian Xu; Yuyu Miao; Gaoxin Zheng; Yong Sun; Xun Xu

    2015-01-01

    Purpose. This study aims to compare the accuracy of intraocular lens power calculation formulas in eyes with long axial lengths from Chinese patients subjected to cataract surgery. Methods. A total of 148 eyes with an axial length of >26 mm from 148 patients who underwent phacoemulsification with intraocular lens implantation were included. The Haigis, Hoffer Q, Holladay 1, and SRK/T formulas were used to calculate the refractive power of the intraocular lenses and the postoperative estimated...

  17. 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

  18. BEBC bubble chamber

    CERN Multimedia

    1972-01-01

    Looking up into the interior of BEBC bubble chamber from the expansion cylinder. At the top of the chamber two fish-eye lenses are installed and three other fish-eye ports are blanked off. In the centre is a heat exchanger.

  19. Controversies in intraocular lens implantation in pediatric uveitis.

    Science.gov (United States)

    Phatak, Sumita; Lowder, Careen; Pavesio, Carlos

    2016-12-01

    Cataract is one of the most common and visually debilitating complications of pediatric uveitis. It develops as a consequence of chronic inflammation and steroid use and is seen most often in juvenile idiopathic arthritis (JIA)-associated uveitis. Cataract extraction with intraocular lens (IOL) insertion has been carried out with a measure of success in non-uveitic pediatric eyes, but in cases of uveitis, multiple factors affect the final outcome. Chronic inflammation and its sequelae such as band keratopathy, posterior synechiae, and cyclitic membranes make surgical intervention more challenging and outcome less certain. Postoperative complications like increased inflammation, glaucoma, posterior capsular opacification, retrolental membranes, and hypotony may compromise the visual outcome. Early refractive correction is imperative in pediatric eyes to prevent amblyopia. The use of contact lenses and intraocular lenses in pediatric uveitic eyes were fraught with complications in the past. Surgical interventions such as vitreo-lensectomy followed by contact lens fitting and small incision cataract surgery followed by different types of intraocular lenses have been utilized, and many reports have been published, albeit in small patient groups. This review analyzes and discusses the existing literature on intraocular lens implantation in cases of pediatric uveitic cataract surgery. PMID:27009616

  20. Development and experimental verification of an intraocular scattering model

    Science.gov (United States)

    Jiang, Chong-Jhih; Jhong, Tian-Siang; Chen, Yi-Chun; Sun, Ching-Cherng

    2011-10-01

    An intraocular scattering model was constructed in human eye model and experimentally verified. According to the biometric data, the volumetric scattering in crystalline lens and diffusion at retina fundus were developed. The scattering parameters of cornea, including particle size and obscuration ratio, were varied to make the veiling luminance of the eye model matching the CIE disability glare general formula. By replacing the transparent lens with a cataractous lens, the disability glare curve of cataracts was generated and compared with that of transparent lenses. The MTF of the intraocular scattering model showed nice correspondence with the data measured by a double-pass experiment.

  1. Intraocular lens employed for cataract surgery

    Science.gov (United States)

    Roszkowska, A. M.; Torrisi, L.

    2014-04-01

    The aim of this paper is to illustrate the techniques of cataract surgery with implantation of intraocular lenses and some physical properties of the used materials. The new technology, coupled with extensive experience and the studied cases, permits to increase the standardization and accuracy of the engravings, by reducing the use and handling of surgical instruments inside the eye. At present it is possible to replace the cataract with crystalline lenses based on biopolymers such as PMMA, silicone, acrylic hydrophilic and hydrophobic acrylic. These materials are increasingly able to replace the natural lens and to ensure the fully functional of the eye. The role of femtosecond lasers in cataract surgery, to assist or replace several aspects of the manual cataract surgery, are discussed.

  2. Intraocular lens employed for cataract surgery

    International Nuclear Information System (INIS)

    The aim of this paper is to illustrate the techniques of cataract surgery with implantation of intraocular lenses and some physical properties of the used materials. The new technology, coupled with extensive experience and the studied cases, permits to increase the standardization and accuracy of the engravings, by reducing the use and handling of surgical instruments inside the eye. At present it is possible to replace the cataract with crystalline lenses based on biopolymers such as PMMA, silicone, acrylic hydrophilic and hydrophobic acrylic. These materials are increasingly able to replace the natural lens and to ensure the fully functional of the eye. The role of femtosecond lasers in cataract surgery, to assist or replace several aspects of the manual cataract surgery, are discussed.

  3. Effect of an ultraviolet-filtering intraocular lens on cystoid macular edema

    International Nuclear Information System (INIS)

    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

  4. 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.

  5. Bilateral intraocular dirofilariasis

    Directory of Open Access Journals (Sweden)

    Viney Gupta

    2014-01-01

    Full Text Available Ocular dirofilariasis mostly presents as a subconjunctival or eyelid lesion. [1] Intraocular dirofilarial infestation is rare. [2],[3] We report a case of a young woman who was accidentally detected to have a live motile worm in the anterior segment in one eye and a cystic lesion on the optic disc in the other eye. To our knowledge, bilateral intraocular dirofilariasis has never been reported.

  6. Cluster Lenses

    CERN Document Server

    Kneib, Jean-Paul; 10.1007/s00159-011-0047-3

    2012-01-01

    Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining...

  7. 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

    OpenAIRE

    Raul de Camargo Vianna Filho; Lincoln de Freitas; Norma Allemann; Ana Luísa Hofling de Lima

    2000-01-01

    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 a...

  8. [The progress of studies on intraocular lens implantation in cataract with high myopia].

    Science.gov (United States)

    Liu, Xue; Wan, Xiuhua

    2015-07-01

    With development of the technology of cataract surgery, combined phacoemulsification and intraocular lens implantation in cataract with high myopia has been widely carried out in clinical treatment. Due to the particularity of high myopia, phacoemulsification in patients with cataract and high myopia is difficult and has recently received a lot of attentions. In this paper, preoperative examinations, the selection of intraocular lenses, surgery methods and surgical complications of cataract surgery in patients with cataract and high myopia are briefly reviewed. PMID:26310259

  9. Symbolic algebra approach to the calculation of intraocular lens power following cataract surgery

    Science.gov (United States)

    Hjelmstad, David P.; Sayegh, Samir I.

    2013-03-01

    We present a symbolic approach based on matrix methods that allows for the analysis and computation of intraocular lens power following cataract surgery. We extend the basic matrix approach corresponding to paraxial optics to include astigmatism and other aberrations. The symbolic approach allows for a refined analysis of the potential sources of errors ("refractive surprises"). We demonstrate the computation of lens powers including toric lenses that correct for both defocus (myopia, hyperopia) and astigmatism. A specific implementation in Mathematica allows an elegant and powerful method for the design and analysis of these intraocular lenses.

  10. 非球面人工晶状体在个体化人眼模型中成像质量的研究%Optical quality of aspheric intraocular lenses in individual eye models

    Institute of Scientific and Technical Information of China (English)

    南莉; 汤欣; 刘永基

    2011-01-01

    Objective An aspheric intraocular lens (IOL) with fixed spherical aberration (SA) implanted in an individual patient will not always obtain ideal optical quality since human corneal structure and SA have large individual variations.The aim of this research was to study optical performance of individual pseudophakic eye models that were constructed based on individual anatomic parameters and implanted IOL with different optical designs.Methods Computer numerical simulation experiment.The anatomic parameters of individual pseudophakic patients were obtained by Pentacam and IOL Master.Parameters were input into ZEMAX to build individual eye models.Three aspheric IOL (SofPort AO,Tecnis Z9000,FY60AD) and one spherical IOL (YA60BBR) were implanted into individual eye models.Modulation transfer function (MTF) and contrast sensitivity function (CSF) were calculated for 3 mm to 5 mm pupil diameters and 550 nm wavelength.Results The height of the MTF and CSF curves were decreased with larger pupils.They were similar with the 4 IOL implanted in the individual eye models for 3 mm pupil diameter,but they were different from each other for 4 and 5 mm pupils,indicating that individual people with different anatomic structures need certain types of IOL to obtain optimal optical performance.This phenomenon was more pronounced for larger pupil.Conclusion The individual eye model based on an individual patient's anatomic parameters should mimic the optical performance of an individual's eye.The type of IOL is varied to obtain optimal optical performance for the optical system of the human eye with different anatomic structures.We should choose an IOL based on the individual eye's structure to obtain optimal retinal image clinically.%目的 根据不同患者眼部解剖参数建立个体化眼模型,研究植入不同设计的人工晶状体(IOL)后的光学表现.方法 计算机数字模拟实验.采用Pentacam眼前节分析系统、IOL Master采集白内障摘除联合IOL植入

  11. Estimation of visual performance of two diffractive multifocal intraocular lenses%两种常用衍射型多焦点人工晶状体的视觉评估

    Institute of Scientific and Technical Information of China (English)

    季樱红; 卢奕; 汪琳; 蒋永祥

    2010-01-01

    Objective To evaluate the visual performance after implantation of the Tecnis ZM900 multifocal intraocular lens (IOL) ( TMF) and the Restor SA60D3 multifocal IOL (Restor). Methods In a prospective study, TMF or Restor was implanted randomly in 73 patients (90 eyes) . The following parameters were assessed 3 months after surgery: refraction, uncorrected and best corrected visual acuities (VA) for distance, intermediate, near and different contrast levels, reading ability, pupil size, wave-front error, defocus curve and position of IOL Patient satisfaction (overall satisfaction, spectacle independence, photic phenomena) was assessed by a questionnaire. The chi-square test was applied to compare categorical variables and Mann-Whitney U test was used to compare the measured data. Results The uncorrected, best corrected and/or distance-corrected VA for distance, intermediate, near and different contrast levels did not show statistically significant differences between the two groups (P > 0. 05 ). Near reading acuity and reading speed were better in TMF under low-light conditions (Z= -2.579, P=0.009; Z = -5.244, P=0.000). The curve of defocus showed that TMF had significantly better intermediate distance (at 50 cm) (Z = -5.300, P = 0.000) and worse near distance (from 25 to 28 cm) than those of Restor (Z= -3.745, P = 0. 000; Z= -5. 691, P=0. 000). Measurements under pupil diameter at 3. 0 mm and 5. 0 mm, ocular and intraocularZ (4, 0) were significantly lower (Z = -8.175, P = 0.000; Z= -5.210, P=0.000andZ = -4.453, P=0.000; Z= -3.790, P = 0.000) , the values of PSF Strehl Ratio and MTF AreaRatio A/D were significantly higher (Z = - 3. 047, P = 0. 002; Z = - 3. 672, P = 0. 008 and Z = - 2. 038, P = 0.042; Z = -2.579, P =0.009) in TMF than those in Restor. On the questionnaire, there was no difference of overall satisfaction, spectacle independence and photic phenomena (P > 0.05 ). Conclusions Implantation of the TMF and Restor offers excellent distant and near VA. Restor

  12. Ophthalmic Lenses

    CERN Document Server

    Bhootra, Ajay Kumar

    2009-01-01

    This book is uniquely meant for the ophthalmologists, optometrists and opticians to help the world see better by excellent vision through the services of technicians and clinical principle based ophthalmology so that the management of ocular problems can be done for a better vision . Informs that a wide range of material and design of ophthalmic lenses with innovative developments is available. This book presents comprehensively rich information about the ophthalmic lenses and their dispensing tips . It will be highly useful mainly for the students of optometry and opticians, ophthalmologists,

  13. Artiflex versus STAAR® implantable contact lenses for correction of high myopia

    Directory of Open Access Journals (Sweden)

    Mohammad Ghoreishi

    2011-01-01

    Conclusion : These two lenses have similar outcomes except in the incidence rate of anterior chamber cell and flare reaction that is greater in the Artiflex group. So, these two lenses are safe with predictable outcome in treating high myopia.

  14. 晶状体半脱位白内障术中两类折叠型 lOL做悬吊术的疗效比较%Observation of two types of foldable scleral - fixated posterior chamber intraocular lens to treat cataract dislocation

    Institute of Scientific and Technical Information of China (English)

    邓芳祝; 邝国平

    2014-01-01

    AlM:To observe the clinical efficacy of two types of scleral-fixated posterior chamber intraocular lens ( lOL ) combined intra-capsule lens extraction to treat cataract dislocation. METHODS: After intra - capsule lens extraction of dislocated cataract, two types of lOL were used as scleral-fixated posterior chamber lOL . First group was with four seal loops, the second group was with two open loops. All 21 patients (23 eyes) took the examination of the best corrected visual acuity, intraocular pressure, fundus, and lOL decentration using camera system attached to slit - lamp ophthalmoscope and lOL tilted using ultrasound biomicroscopy (UBM) at 6mo after surgery.RESULTS: After 6mo, all patients had improved eye sight. There was significant difference in the mean lOL decentration between the two groups ( 0. 57mm vs 0. 79mm, P CONCLUSlON: lOL with four loops are more appropriate as scleral-fixated posterior chamber lOL with less tiltness and dicentration.%目的:探讨囊内摘除联合两类人工晶状体( intraocular lens,IOL)做悬吊术治疗晶状体半脱位白内障的临床疗效。  方法:晶状体半脱位患者21例23眼,行晶状体囊内摘除前部玻璃体切割联合IOL悬吊术,依植入IOL类别分为四个闭合襻IOL组和两个C襻IOL组,术后观察视力、眼压、综合验光、眼底,6mo时裂隙灯眼前节摄像系统拍照确定 IOL 偏心值,超声生物显微镜( ultrasound biomicroscopy,UBM)检查确定IOL的倾斜度检查。  结果:所有患眼术后视力均有不同程度的提高。四襻组IOL平均偏心为0.57mm,两襻组平均偏心0.79mm;四襻组IOL平均倾斜度为6°,两襻组平均倾斜度11°,两组间差异均有统计学意义(P  结论:晶状体半脱位术中四个闭合襻IOL做悬吊术后居中性更好,IOL倾斜度更小。

  15. 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.

  16. Acoustic lenses

    International Nuclear Information System (INIS)

    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

  17. Smart lenses

    International Nuclear Information System (INIS)

    If you wear glasses and want to protect your eyes from harmful ultraviolet rays when you step outside into the bright sunshine, you can do a number of things. You can switch to a pair of prescription sunglasses or don some clip-on shades. Alternatively, you can invest in a pair of glasses with 'photochromatic' lenses, which go dark in strong sunlight. Such lenses are said to be 'smart' because they can adapt to their environment without human intervention. An example of a more complex smart system is the adaptive optics used by astronomers to image faint objects. The system compensates for the distorting effect of the atmosphere by first measuring how much a uniform light wavefront is perturbed and then applying an opposite distortion, usually by making the appropriate changes to a deformable mirror. Now, physicists are starting to develop 'adaptive lenses' made from liquids or soft polymer materials that can change their focal length in response to external stimuli. At varying degrees of commercialization, these devices hold great promise in imaging applications where space is at a premium, from mobile-phone cameras to surgical endoscopes. In the November issue of Physics World, Hongrui Jiang and Liang Dong take a look at different methods of producing smart lenses, including 'responsive hydrogels' that focus when given different chemical, biological or physical stimuli. (U.K.)

  18. 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.

  19. Primary Phacoemulsification and Intraocular Lens Implantation for Acute Primary Angle-Closure

    OpenAIRE

    Su, Wei-Wen; Chen, Phil Yeong-Fung; Hsiao, Ching-Hsi; Chen, Henry Shen-Lih

    2011-01-01

    Background To investigate the effect of primary phacoemulsification on intraocular pressure (IOP) in patients with acute primary angle-closure (PAC) and coexisting cataract. Methodology Sixteen eyes of 14 patients with acute PAC received phacoemulsification and intraocular lens implantation as initial management for medically uncontrolled IOP in a retrospective chart review. The effects on IOP, vision, anterior chamber depth (ACD), and number of antiglaucoma medications were evaluated. Princi...

  20. Inflammation after cataract extraction and intraocular lens implantation in patients with rheumatoid arthritis.

    OpenAIRE

    Matsuo, T; Fujiwara, M.; Matsuo, N

    1995-01-01

    AIMS--The purpose of this study was to examine whether preoperative activity of rheumatoid arthritis influences the extent of anterior chamber inflammation after cataract extraction and intraocular lens implantation. METHODS--The medical records of 23 consecutive patients (33 eyes) with rheumatoid arthritis, who underwent cataract extraction with intraocular lens implantation, were reviewed during a 4 year period from April 1990 to March 1994. RESULTS--Eleven patients who still showed a 1+ le...

  1. Malignant intraocular tumors

    International Nuclear Information System (INIS)

    The role of the radiation therapist in the management of malignant intraocular tumors is changing. With more active identification of malignant intraocular tumors, and a better recognization of the manner in which one can deal with problems of radiation sensitivity, radiation techniques of all sorts will be more actively employed in the treatment of these tumors. Special techniques must be selected for appropriate circumstances of management in order to diminish to an absolute minimum the impact upon the lens, the impact upon visual acuity and the impact upon the cornea. Cobalt-60 plaques are being used more commonly in the treatment of melanomas of the choroid, and the role for radiation therapy in the management of retinoblastoma is changing markably to where it may be used as the primary treatment program rather than enucleation. In metastatic disease involving the uveal tract, radiation therapy has assumed the most important role for management. Chemotherapy should be considered as an active adjuvant in the management of not only those individuals with retinoblastoma but also in those identified circumstances where metastases to the uveal tract are being treated. The role for chemotherapy or immunotherapy in malignant melanoma is unclear

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

    Science.gov (United States)

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ...

  3. 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.

  4. Silicone oil-intraocular lens interaction: which lens to use?

    OpenAIRE

    McLoone, E; Mahon, G; Archer, D.; Best, R

    2001-01-01

    AIM—To determine a suitable intraocular lens for implantation in patients at high risk of lens exposure to silicone oil in their lifetime.
METHODS—PMMA, AcrySof, AR40, AQUA-Sense, and Raysoft lenses were examined. Each lens was immersed for 5 minute intervals in balanced salt solution (BSS), in stained silicone oil, and again in BSS before being photographed in air and in BSS. Percentage silicone oil coverage of the lens optic was determined.
RESULTS—The mean percentage coating (MPC) for the ...

  5. Clinical observation on the manual small incision cataract surgery combined with rigid posterior chamber intraocular lens implantation performed by medical team in Africa%援非洲医疗队手法小切口白内障手术效果观察

    Institute of Scientific and Technical Information of China (English)

    郎莉莉; 陈建梅; 崔红平

    2016-01-01

    Objective To investigate the clinical effects of manual small incision cataract surgery combined with rigid posterior chamber intraocular lens implantation in 376 Moroccan cataract cases performed by medical team in Africa.Methods From March 2013 to February 2015 in Morocco,432 eyes of 376 Moroccan patients had undertaken manual small incision cataract surgery combined with rigid posterior chamber lens implantation.The postoperative visual acuity,intraoperative and postoperative complications were analyzed.Results The visual acuities at ≤0.04 were obtained in 9 eyes (2.08%),0.05 ~ 0.25 in 65 eyes(15.05%),0.3 ~0.5 in 236 eyes(54.63%),and≥0.6 in 122 eyes(28.24%) at 1 week postoperatively.The intraoperative complications were stated as follows.The posterior capsular rupture and vitreous prolapse occurred in 28 eyes (6.48%) with nucleus fallen into vitreous cavity in 1 eye,among which 22 eyes were applied posterior chamber lens implantation at stage Ⅰ,the intraocular lens had not been implanted in 6 eyes.Nine eyes (2.08%) complicated with iris prolapse and 12 eyes (2.78%) with progressive miosis.Two eyes(0.46%) complicated with iridodialysis which was sutured intraoperatively.The postoperative complications included the following items.At 1 week postoperatively,corneal edema occurred in 78 eyes(18.06%).The anterior chamber inflammatory responses occurred in 52 eyes(12.04%).The irregular pupil was noticed in 35 eyes (8.10%).The vitreous hemorrhage occurred in 1 eyes(0.23%)which was related to diabetic retinopathy.Other complications were not observed,such as endophthalmitis,secondary glaucoma,intraocular lens dislocation or bullous keratopathy.Conclusion Manual small incision cataract surgery combined with rigid posterior chamber lens implantation is an optimal cataract surgical method in some poverty-striken districts of Africa with the advantages of safety,effectiveness,satisfied results and low cost.And Chinese medical team also

  6. Contact Lenses for Vision Correction

    Science.gov (United States)

    ... Ask an Ophthalmologist Español Eye Health / Glasses & Contacts Contact Lenses Sections Contact Lenses for Vision Correction Proper ... to Know About Contact Lenses Colored Contact Lenses Contact Lenses for Vision Correction Written by: Kierstan Boyd ...

  7. Intraocular coenurosis: a case report.

    OpenAIRE

    Ibechukwu, B. I.; Onwukeme, K. E.

    1991-01-01

    A case of intraocular coenurosis was clinically diagnosed and treated with praziquantel. The drug destroyed the coenurus, but vision was lost through toxic endophthalmitis and retinal detachment. There were no systemic side effects.

  8. Neutrino Lensing

    Institute of Scientific and Technical Information of China (English)

    LUO Xin-Lian

    2009-01-01

    Due to the intrinsic properties of neutrinos, the gravitational lens effect for a neutrino should be more colorful and meaningful than the normal lens effect of a photon. Other than the experiments operated at terrestrial laboratory, in principle, we can propose a completely new astrophysical method to determine not only the nature of the gravity of lens objects but also the mixing parameters of neutrinos by analyzing neutrino trajectories near the central objects.However, the angular, energy and time resolution of the neutrino telescopes are still comparatively poor, so we just concentrate on the two classical tests of general relativity, i.e.the angular deflection and the time delay of the neutrino by a lens object as a preparative work in this paper.In addition, some simple properties of neutrino lensing are investigated.

  9. Anterior Chamber Live Loa loa: Case Report.

    Science.gov (United States)

    Kagmeni, G; Cheuteu, R; Bilong, Y; Wiedemann, P

    2016-01-01

    We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis. PMID:27441005

  10. Anterior Chamber Live Loa loa: Case Report

    Science.gov (United States)

    Kagmeni, G.; Cheuteu, R.; Bilong, Y.; Wiedemann, P.

    2016-01-01

    We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis. PMID:27441005

  11. Treatment of dystrophic calcification on a silicone intraocular lens with pars plana vitrectomy

    OpenAIRE

    Mehta N; Goldberg RA; Shah CP

    2014-01-01

    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 po...

  12. The Impact of Multifocal Intraocular Lens in Retinal Imaging with Optical Coherence Tomography

    OpenAIRE

    Dias-Santos, A; Costa, L; Lemos, V; Anjos, R.; Vicente, A.(IFPA, Dep. AGO, Université de Liège, Bat B5, Sart-Tilman, B-4000, Liège 1, Belgium); Ferreira, J; Cunha, JP

    2015-01-01

    Multifocal intraocular lenses (MF IOLs) have concentric optical zones with different dioptric power, enabling patients to have good visual acuity at multiple focal points. However, several optical limitations have been attributed to this particular design. The purpose of this study is to access the effect of MF IOLs design on the accuracy of retinal optical coherence tomography (OCT). Cross-sectional study conducted at the Refractive Surgery Department of Central Lisbon Hospital Center. Twent...

  13. Anterior chamber cholesterolosis in a patient with retinoblastoma.

    Science.gov (United States)

    Hong, Bryan K; Say, Emil Anthony T; Chévez-Barrios, Patricia; Lee, Thomas C; Kim, Jonathan W

    2016-01-01

    Anterior chamber cholesterolosis is a rare phenomenon typically associated with non-neoplastic conditions such as hyphema or Coats disease; it has never been reported to be associated with intraocular malignancy. We report a case of anterior chamber cholesterolosis presenting in the setting of retinoblastoma and discuss clinical features relevant for its differentiation from Coats disease. PMID:27330481

  14. Cataract surgery to lower intraocular pressure

    Directory of Open Access Journals (Sweden)

    Berdahl John

    2009-01-01

    Full Text Available Cataract and glaucoma are common co morbidities. Cataract surgery is frequently performed in patients with glaucoma. In this study, a review of literature with search terms of cataract, glaucoma and intraocular pressure is followed by evaluation and synthesis of data to determine the effect of cataract surgery on intraocular pressure. Cataract surgery seems to lower intraocular pressure on a sustained basis, especially in patients with higher preoperative intraocular pressure. The mechanism of action of these finds remains speculative.

  15. A novel index for predicting intraocular pressure reduction following cataract surgery

    OpenAIRE

    Issa, S A; Pacheco, J.; Mahmood, U; Nolan, J; Beatty, S

    2005-01-01

    Aim: The results of a study designed to investigate the predictive value of preoperative anterior chamber depth (ACD) and intraocular pressure (IOP) are reported. The relation between these factors and their effect on the reduction in IOP following phacoemulsification cataract surgery was also studied.

  16. Sildenafil Accelerates Anterior Chamber Refilling after Paracentesis in Sheep and Rabbits

    OpenAIRE

    Gerometta, Rosana; Alvarez, Lawrence J.; Candia, Oscar A.

    2012-01-01

    Systemic ingestion of sildenafil accelerated the rate of refilling of the anterior chamber with “secondary” aqueous after paracentesis in sheep and rabbits, as determined by monitoring changes in intraocular pressure.

  17. Pigment dispersion syndrome associated with intraocular lens implantation: a new surgical technique

    Directory of Open Access Journals (Sweden)

    M Isabel Canut Jordana

    2010-11-01

    Full Text Available M Isabel Canut Jordana1, Daniel Pérez Formigó1, Rodrigo Abreu González2, Jeroni Nadal Reus11Barraquer Ophthalmology Centre, Barcelona, Spain; 2University Hospital of La Candelaria, Tenerife, SpainAims: We report the case of a myopic patient who, after intraocular lens transplant in the posterior chamber, suffered elevated intraocular pressure due to pigment dispersion, with recurrent episodes of blurred vision. The patient was treated with a new surgical technique that can avoid potential iridolenticular contact.Methods: Complete ophthalmologic examination and optical coherence tomography (OCT of the anterior segment were performed.Results: Contact between the pigmentary epithelium and the iris with an intraocular lens was revealed by utrasound biomicroscopy and OCT. In this case, Nd:YAG laser iridotomy and laser iridoplasty were not effective for iridolenticular separation and control of the pigment dispersion. We propose a new technique: stitches on the surface of the iris to obtain good iridolenticular separation and good intraocular pressure control.Conclusion: Stitches on the iris surface should be considered as optional therapy in pigmentary glaucoma secondary to intraocular lens implantation. This surgical technique can avoid potential iridolenticular contacts more definitively.Keywords: pigmentary glaucoma, intraocular lens, optical coherence tomography, laser

  18. Role of cataract surgery in lowering intraocular pressure

    International Nuclear Information System (INIS)

    To study the effects of cataract surgery in lowering of intraocular pressure (IOP). Study Design: Retrospective study. Place and Duration of Study: The Department of Ophthalmology, Combined Military Hospital, Rawalpindi from January 2011 to December 2013. Patients and Methods: The study included a total of 250 patients; of which 100 cases had simple cataract with no coexisting disease, 100 cases had cataract with primary open angle glaucoma and 50 cases of cataract had accompanying pseudoexfoliation glaucoma. All patients were assessed and recorded preoperatively for their IOP, vision, depth of anterior chamber (ACD), angle of anterior chamber by gonioscopy and glaucoma medications being used. Cataract surgery was performed by phacoemulsification and IOL implantations in all cases. These patients were followed up for a period of six months. Results: The intraocular ressure of all these patients was recorded at monthly interval for six months. The IOP showed a significant decrease in all cases and remained constant till the end of the study. A marked improvement of vision was noted in all cases. The depth of the anterior chamber increased and the angle also widened in all cases. Discussion: Cataract surgery has been found to reduce IOP along with improvement in vision. Patients with glaucoma have a dual benefit of reduced IOP and visual improvement after cataract surgery. (author)

  19. Multimodal characterization of contact lenses

    Science.gov (United States)

    Marcus, Michael A.; Compertore, David; Gibson, Donald S.; Herbrand, Matthew E.; Ignatovich, Filipp V.

    2015-10-01

    A table top instrument has been designed, constructed and tested to characterize all of the primary optical and physical properties of contact lenses. Measured optical properties include base power, cylinder power, cylindrical axis, prism, refractive index and wavefront aberrations. Measured physical properties include center thickness, lens diameter and lens sagittal depth. The instrument combines a Shack-Hartmann wavefront sensor (SHWS), a machine vision sensor, and a low coherence light interferometer (LCI) all coaxially aligned into a single tabletop unit. The unit includes a cuvette, mounted in a translatable sample chamber for holding the contact lens under test, and it can be configured to measure wet or dry contact lenses. During operation, the vision sensor measures the diameter of the lens, and locates the center of the lens. The lens is then aligned for other measurements. The vision sensor can also measure various alignment marks on the lens, as well as identify any alpha numerical features, which can be used to associate the lens orientation with the measured aberrations. The LCI measures the center thickness, sagittal depth and index of refraction of the contact lens. The base radius of curvature is then calculated using these measured parameters. The SHWS measures the lenses prescription power, including spherical, cylinder, prism, and higher order wavefront aberrations. NIST traceable calibration artifacts are used to calibrate the SHWS, machine vision and LCI modalities. Repeatability measurements on a contact lens in a saline solution are presented.

  20. Broadband waveplate lenses.

    Science.gov (United States)

    Tabiryan, Nelson V; Serak, Svetlana V; Nersisyan, Sarik R; Roberts, David E; Zeldovich, Boris Ya; Steeves, Diane M; Kimball, Brian R

    2016-04-01

    We report on lenses that operate over the visible wavelength band from 450 nm to beyond 700 nm, and other lenses that operate over a wide region in the near-infrared from 650 nm to beyond 1000 nm. Lenses were recorded in liquid crystal polymer layers only a few micrometers thick, using laser-based photoalignment and UV photopolymerization. Waveplate lenses allowed focusing and defocusing laser beams depending on the sign of the circularity of laser beam polarization. Diffraction efficiency of recorded waveplate lenses was up to 90% and contrast ratio was up to 500:1. PMID:27137003

  1. Gravitational Lensing in Astronomy

    CERN Document Server

    Wambsganss, J

    1998-01-01

    Deflection of light by gravity was predicted by General Relativity and observationaly confirmed in 1919. In the following decades various aspects of the gravitational lens effect were explored theoretically, among them the possibility of multiple or ring-like images of background sources, the use of lensing as a gravitational telescope on very faint and distant objects, and the possibility to determine Hubble's constant with lensing. Only relatively recently gravitational lensing became an observational science after the discovery of the first doubly imaged quasar in 1979. Today lensing is a booming part of astrophysics. In addition to multiply-imaged quasars, a number of other aspects of lensing have been discovered since, e.g. giant luminous arcs, quasar microlensing, Einstein rings, galactic microlensing events, arclets, or weak gravitational lensing. By now literally hundreds of individual gravitational lens phenomena are known. Although still in its childhood, lensing has established itself as a very use...

  2. Small-Gauge Pars Plana Vitrectomy for the Management of Symptomatic Posterior Vitreous Detachment after Phacoemulsification and Multifocal Intraocular Lens Implantation: A Pilot Study from the Pan-American Collaborative Retina Study Group

    OpenAIRE

    Navarro, Rodrigo M.; Machado, Leonardo M.; Ossires Maia; Lihteh Wu; Farah, Michel E.; Octaviano Magalhaes; J Fernando Arevalo; Mauricio Maia

    2015-01-01

    Purpose. To determine the efficacy of 23-gauge pars plana vitrectomy (PPV) for symptomatic posterior vitreous detachment (PVD) on visual acuity (VA) and quality after multifocal intraocular lenses (IOLs). Methods. In this prospective case series, patients who developed symptomatic PVD and were not satisfied with visual quality due to floaters and halos after multifocal IOL implantation underwent PPV. Examinations included LogMAR uncorrected visual acuity (UCVA), intraocular pressure, biomicro...

  3. 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.

  4. Cosmology with Doppler Lensing

    OpenAIRE

    Bacon, David; Andrianomena, Sambatra; Clarkson, Chris; Bolejko, C.; Maartens, Roy

    2014-01-01

    Doppler lensing is the apparent change in object size and magnitude due to peculiar velocities. Objects falling into an overdensity appear larger on its near side, and smaller on its far side, than typical objects at the same redshifts. This effect dominates over the usual gravitational lensing magnification at low redshift. Doppler lensing is a promising new probe of cosmology, and we explore in detail how to utilize the effect with forthcoming surveys. We present cosmological simulations of...

  5. Long-term change in intraocular pressure after extracapsular cataract extraction with posterior chamber intraocular lens implantation versus phacoemulsification with posterior chamber intraocular lens implantation in Indians

    Directory of Open Access Journals (Sweden)

    Virendra K Pal

    2013-01-01

    Conclusion: Significant IOP reduction may be expected after cataract surgery with either ECCE or phacoemulsification with IOL implantation. The lowering of IOP became statistically significant at about 2 months post-operatively, but became almost stable after the 4 th month.

  6. 21 CFR 886.3600 - Intraocular lens.

    Science.gov (United States)

    2010-04-01

    ... the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens. 886.3600 Section 886.3600 Food... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification....

  7. Automatic intraocular lens segmentation and detection in optical coherence tomography images.

    Science.gov (United States)

    Gillner, Melanie; Eppig, Timo; Langenbucher, Achim

    2014-05-01

    We present a new algorithm for automatic segmentation and detection of an accommodative intraocular lens implanted in a biomechanical eye model. We extracted lens curvature and position. The algorithm contains denoising and fan correction by a multi-level calibration routine. The segmentation is realized by an adapted canny edge detection algorithm followed by a detection of lens surface with an automatic region of interest search to suppress non-optical surfaces like the lens haptic. The optical distortion of lens back surface is corrected by inverse raytracing. Lens geometry was extracted by a spherical fit. We implemented and demonstrated a powerful algorithm for automatic segmentation, detection and surface analysis of intraocular lenses in vitro. The achieved accuracy is within the expected range determined by previous studies. Future improvements will include the transfer to clinical anterior segment OCT devices. PMID:23928353

  8. spark chamber

    CERN Multimedia

    A few cosmic rays pass through your body every second of every day, no matter where you are. Look at the spark chamber to your right – every flash is the track made by a cosmic ray from outer space. The spark chamber is filled with a special gas mixture. Cosmic rays knock electrons out of the atoms in the gas. These electrons accelerate towards high voltage metal strips layered throughout the chamber, creating sparks like little bolts of lightning.

  9. spark chamber

    CERN Multimedia

    A few cosmic rays pass through your body every second of every day, no matter where you are. Look at the spark chamber to your right – every flash is the track made by a cosmic ray from outer space. The spark chamber is filled with a special gas mixture. Cosmic rays knock electrons out of the atoms in the gas. These electrons accelerate towards high voltage metal strips layered throughout the chamber, creating sparks like little bolts of lightning.

  10. 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…

  11. Effects of systemic domestic recombinant human erythropoietin on HIF-1α expression in the retina in a rabbit model of acute high intraocular pressure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To observe the expression of hypoxia inducible factor-1α (HIF-1α) in the retina of rabbits with acute high intraocular pressure and to investigate the mechanism of systemic domestic recombinant human erythropoietin (rhEPO) protecting the retina from ischemia-reperfusion injury. Methods First,control group and model group were established in rabbit eyes. The acute high intraocular pressure model was established by saline perfusion into anterior chamber,and then hypodermic injection of domestic rhEP...

  12. Cosmology with Gravitational Lensing

    CERN Document Server

    Heavens, Alan

    2011-01-01

    In these lectures I give an overview of gravitational lensing, concentrating on theoretical aspects, including derivations of some of the important results. Topics covered include the determination of surface mass densities of intervening lenses, as well as the statistical analysis of distortions of galaxy images by general inhomogeneities (cosmic shear), both in 2D projection on the sky, and in 3D where source distance information is available. 3D mass reconstruction and the shear ratio test are also considered, and the sensitivity of observables to Dark Energy is used to show how its equation of state may be determined using weak lensing. Finally, the article considers the prospect of testing Einstein's General Relativity with weak lensing, exploiting the differences in growth rates of perturbations in different models.} \\abstract{In these lectures I give an overview of gravitational lensing, concentrating on theoretical aspects, including derivations of some of the important results. Topics covered include...

  13. The Orphan Lenses Project

    Science.gov (United States)

    Moustakas, Leonidas A.; Brownstein, J.; Fadely, R.; Fassnacht, C. D.; Gavazzi, R.; Goodsall, T.; Griffith, R. L.; Keeton, C. R.; Kneib, J. P.; Koekemoer, A.; Koopmans, L. V. E.; Marshall, P. J.; Merten, J.; Metcalf, R. B.; Oguri, M.; Papovich, C.; Rein, H.; Ryan, R.; Stewart, K. R.; Treu, T.

    2012-01-01

    Strong gravitational lenses are uniquely suited for the study of dark matter structure and substructure within massive halos of many scales, act as gravitational telescopes for distant faint objects, and can give powerful and competitive cosmological constraints. Some 300 lenses have been identified in the literature in one form or another; many others have been found, but perhaps have not warranted dedicated publications. The Orphan Lenses project aims to be a master compilation of all strong gravitational lenses that are known, and a community repository for candidate lenses. A clear and uniform database of basic properties and gravitational lens models is being developed, which will be available online and through a smartphone interactive application. I will present the project, and scientific highlights with this dataset.

  14. Intraocular Lens Opacification following Intracameral Injection of Recombinant Tissue Plasminogen Activator to Treat Inflammatory Membranes after Cataract Surgery

    OpenAIRE

    2015-01-01

    Purpose. To report 7 cases of intraocular lens (IOL) opacification following treatment of postoperative anterior chamber fibrin with recombinant tissue plasminogen activator (rtPA) after cataract surgery. Methods. Retrospective case series of 7 eyes in 7 patients who developed IOL opacification after receiving rtPA for anterior chamber inflammatory membrane formation resulting from phacoemulsification cataract surgery. Three explanted IOLs were investigated with light microscopy, histochemica...

  15. Ussing Chamber

    NARCIS (Netherlands)

    Westerhout, J.; Wortelboer, H.; Verhoeckx, K.

    2015-01-01

    The Ussing chamber system is named after the Danish zoologist Hans Ussing, who invented the device in the 1950s to measure the short-circuit current as an indicator of net ion transport taking place across frog skin (Ussing and Zerahn, Acta Physiol Scand 23:110-127, 1951). Ussing chambers are increa

  16. Anterior chamber flare after trabeculectomy and after phacoemulsification

    OpenAIRE

    Siriwardena, D; Kotecha, A; Minassian, D; Dart, J.; KHAW, P.

    2000-01-01

    AIMS—To evaluate and compare prospectively the anterior chamber inflammatory response after phacoemulsification cataract surgery and after trabeculectomy with peripheral iridectomy.
METHODS—Anterior chamber inflammation was measured using the Kowa FM-500 laser flare meter in 131 patients undergoing trabeculectomy and 148 patients undergoing phacoemulsification cataract extraction with intraocular lens implantation. Flare was measured before surgery and on each postoperative visit up to 12 mon...

  17. Effect of intraocular lens implantation on combined extracapsular cataract extraction with trabeculectomy: a comparative study.

    OpenAIRE

    Neumann, R.; Zalish, M.; Oliver, M.

    1988-01-01

    In an attempt to assess the effect of posterior chamber intraocular lens (IOL) implantation on the outcome of combined extracapsular cataract extraction (ECCE) and trabeculectomy we compared 23 eyes subjected to ECCE and trabeculectomy with 23 eyes subjected to a triple procedure-that is, with the addition of IOL implantation. The results showed that IOL implantation did not have a detrimental effect on postoperative IOP reduction, gain in visual acuity, or needs for antiglaucoma medication. ...

  18. Cataract surgery and intraocular pressure.

    Science.gov (United States)

    Melancia, Diana; Abegão Pinto, Luis; Marques-Neves, Carlos

    2015-01-01

    Cataract surgery is one of the most performed surgeries in the developed world. In addition to its significant impact on visual acuity, phacoemulsification has been hailed as a potential intraocular pressure (IOP)-lowering procedure. While current evidence suggests an overall significant and sustained decrease in IOP to exist after cataract surgery, the specific ocular characteristics that could help predict which patients are likely to benefit from this IOP-lowering effect remain unclear. This definition is important in glaucoma patients if this surgery is to be used in the treatment for this disease. Our review aims to summarize the literature on the subject, depicting possible mechanisms behind this IOP decrease, which type of patients are more likely to benefit from this surgery for IOP-lowering purposes and ultimately help optimizing disease management for the increasing number of patients with concomitant glaucoma and cataract. PMID:25765255

  19. Cytomegalovirus retinitis mimicking intraocular lymphoma

    Directory of Open Access Journals (Sweden)

    Patrick Gooi

    2008-12-01

    Full Text Available Patrick Gooi1, James Farmer2, Bernard Hurley3, Elliott Brodbaker41Department of Ophthalmology, University of Calgary, Calgary, Alberta, Canada; 2Department of Pathology and Lab Medicine University of Ottawa and The Ottawa Hospital, Ottawa, Ontario, Canada; 3Department of Ophthalmology, University of Ottawa Eye Institute and The Ottawa Hospital, Ottawa, Ontario, Canada; 4Faculty of Medicine, University of Ottawa, Ottawa, Ontario, CanadaAbstract: We present a case of an unusual retinal infiltrate requiring retinal biopsy for definitive diagnosis. A 62-year-old man with treated lymphoma presented with decreased vision in the right eye associated with a white retinal lesion, which extended inferonasally from an edematous disc. Intraocular lymphoma was considered as a diagnosis; thus, the patient was managed with vitrectomy and retinal biopsy. Cytological analysis of the vitreous aspirate could not rule out a lymphoproliferative disorder. The microbial analysis was negative. Histology of the lesion showed extensive necrosis and large cells with prominent nucleoli. To rule out lymphoma, a battery of immunostains was performed and all were negative. However the limited amount of tissue was exhausted in the process. Subsequently, a hematoxylin and eosin (H/E slide was destained, on which a CMV immunostain was performed. This revealed positivity in the nuclei and intranuclear inclusions within the large atypical cells. A diagnosis of CMV retinitis was made. Retinal biopsy may provide a definitive diagnosis and direct patient care toward intravenous gancyclovir in the case of CMV or toward radiation and chemotherapy for intraocular lymphoma. When faced with a limited amount of tissue, destaining regular H/E slides is a possible avenue to performing additional immunohistochemical studies.Keywords: CMV retinitis, retinal biopsy, immunohistochemistry, destaining

  20. Wire Chamber

    CERN Multimedia

    1986-01-01

    Two wire chambers made originally for the R807 Experiment at CERN's Intersecting Storage Rings. In 1986 they were used for the PS 201 experiment (Obelix Experiment) at LEAR, the Low Energy Antiproton Ring. The group of researchers from Turin, using the chambers at that time, changed the acquisition system using for the first time 8 bit (10 bit non linear) analog to digital conversion for incoming signals from the chambers. The acquisition system was controlled by 54 CPU and 80 digital signal processors. The power required for all the electronics was 40 kW. For the period, this system was one of the most powerful on-line apparatus in the world. The Obelix Experiment was closed in 1996. To find more about how a wire chamber works, see the description for object CERN-OBJ-DE-038.

  1. Vacuum chamber

    International Nuclear Information System (INIS)

    A detailed description is given of the vacuum chamber of the so-called experimental equipment DEMAS (double-arm-time-of-flight spectrometer) at the heavy ion accelerator U-400 at the JINR-Dubna. (author)

  2. Artiflex versus STAAR® implantable contact lenses for correction of high myopia

    OpenAIRE

    Mohammad Ghoreishi; Amin Masjedi; Kobra Nasrollahi; Aminhossein Rahgozar; Keivan Jenab; Hamid Fesharaki

    2011-01-01

    Purpose : To compare two phakic intraocular lenses, Artiflex and STAAR® implantable contact lens (ICL), in high myopia. Setting : Isfahan Ophthalmology Clinic, Iran. Materials and Methods : In a randomized, prospective clinical trial study, 40 eyes of 20 patients who came to Isfahan ophthalmology clinic to correct their refractive error were examined. Artiflex was inserted in 20 eyes and ICL in the other 20 eyes. After 1 year, uncorrected visual acuity (UCVA), best corrected visual ac...

  3. Effect of hemodialysis on intraocular lens power calculation.

    Science.gov (United States)

    Çalışkan, Sinan; Çelikay, Osman; Biçer, Tolga; Aylı, Mehmet Deniz; Gürdal, Canan

    2016-03-01

    Background To evaluate changes in ocular biometric parameters after hemodialysis (HD) in patients with end-stage renal disease (ESRD). Methods Forty eyes of 40 patients undergoing HD were included in this cross-sectional study. Keratometry (K) readings, white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber depth (ACD), pupil diameter, lens thickness (LT), axial length (AL), and intraocular lens (IOL) power calculation were measured with Lenstar LS 900 (Haag Streit AG, Koeniz, Switzerland) before and after hemodialysis. Intraocular pressure (IOP) was measured with a non-contact tonometer (Tonopachy NT-530P, Nidek Co., LTD, Tokyo, Japan). Main outcomes were changes in biometric parameters after HD. Reliability of the measurements (intraclass correlation coefficients (ICCs)) and the effect size (Cohen's d) were also calculated. Results Mean difference in AL before and after HD was -0.041 ± 0.022 mm with ICCs > 0.90 (p  0.90 (p = 0.041 and Cohen's d = 0.20). Hemodialysis had no significant effect on K readings, WTW distance, CCT, ACD, LT, or IOP. Conclusion Axial length and pupil diameter increase after HD with small effect size, while HD does not significantly affect IOL power calculations. PMID:26707804

  4. 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...

  5. Cosmology with gravitational lenses

    Science.gov (United States)

    Falco, E. E.

    2009-05-01

    Gravitational lenses yield a very high rate of return on observational investment. Given their scarcity, their impact on our knowledge of the universe is very significant. In the weak-field limit, lensing studies are based on well-established physics and thus offer a straightforward approach to pursue many currently pressing problems of astrophysics. Examples of these are the significance of dark matter and the density, age and size of the universe. I present recent developments in cosmological applications of gravitational lenses, regarding estimates of the Hubble constant using strong lensing of quasars. I describe our recent measurements of time delays for the images of SDSS1004+4112, and discuss prospects for the future utilizing synoptic telescopes, planned and under construction.

  6. COSMOLOGY WITH GRAVITATIONAL LENSES

    Directory of Open Access Journals (Sweden)

    Emilio E. Falco

    2009-01-01

    Full Text Available Gravitational lenses yield a very high rate of return on observational investment. Given their scarcity, their impact on our knowledge of the universe is very signi cant. In the weak- eld limit, lensing studies are based on well-established physics and thus o er a straightforward approach to pursue many currently pressing problems of astrophysics. Examples of these are the signi cance of dark matter and the density, age and size of the universe. I present recent developments in cosmological applications of gravitational lenses, regarding estimates of the Hubble constant using strong lensing of quasars. I describe our recent measurements of time delays for the images of SDSS J1004+4112, and discuss prospects for the future utilizing synoptic telescopes, planned and under construction.

  7. Types of Contact Lenses

    Science.gov (United States)

    ... procedure is primarily used for the correction of myopia (nearsightedness). Overnight Ortho-K lenses are the most ... prescribed maintenance schedule in order to maintain the treatment effect. Your eye care professional will determine the ...

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

    Science.gov (United States)

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

    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. Design of a Test Bench for Intraocular Lens Optical Characterization

    International Nuclear Information System (INIS)

    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

  10. 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

  11. 'In-the-bag' hyphaema--a rare complication of posterior chamber lens implantation.

    OpenAIRE

    Thomas, R; Aylward, G W; Billson, F A

    1989-01-01

    A 72-year-old woman developed a hyphaema on the first postoperative day after a combined trabeculectomy and extracapsular cataract extraction with posterior chamber intraocular lens implantation. On the second day the blood had redistributed to accumulate 'in the bag' posterior to the intraocular lens and had formed a fluid level. Postural drainage helped to clear the hyphaema from both locations, with no short-term effect on visual function or the filtering bleb.

  12. Periocular migration of an intraocular lens.

    OpenAIRE

    Jenkins, C.

    1992-01-01

    A woman presented with a painful eye 6 weeks after cataract extraction and intraocular lens implantation. In the past she had had a sector iridectomy for iris bombé caused by chronic anterior uveitis. On examination the three central corneal sutures were absent, whilst the medial and lateral sutures had broken and were protruding from the section. The eye was quiet and the section intact. Combined clinical and ultrasound examination failed to locate the intraocular lens. Four months postopera...

  13. Intraocular cilia associated with perforating injury

    Directory of Open Access Journals (Sweden)

    Gopal Lingam

    2000-01-01

    Full Text Available Purpose: To report a case series of penetrating injury complicated by occurrence of intraocular cilia. Methods: Retrospective analysis of charts of 11 eyes of 11 patients with penetrating injury and intraocular cilia, presenting between September 1978 and November 1998. Ten eyes underwent surgery for trauma-related problems such as cataract, vitritis, retinal detachment etc., at which time intraocular cilia were removed. One eye did not have surgery and continues to harbour cilia at the posterior perforation site. Results: Metallic wire was responsible for injury in 6 of 11 eyes with intraocular cilia. Five eyes had significant intraocular inflammation. The cilia were located in the anterior segment in 4 eyes; in the posterior segment in 6 eyes and in both in one eye. At the last follow up, 72.7% had 6/18 or better vision. Poor vision in the rest was due to recurrent retinal detachment (2 eyes and macular scarring (1 eye. Conclusion: Intraocular cilia are more commonly associated with injury by a metallic wire. The presentation and management of an injured eye does not seem to be influenced by the presence of cilia in the eye.

  14. Ectopic intraocular lens: An unusual complication of cataract surgery

    Directory of Open Access Journals (Sweden)

    Mehul A Shah

    2014-01-01

    Full Text Available We wish to report an unusual complication of intraocular lens (IOL insertion following uneventful phacoemulsification. After successful phacoemulsification surgery, a hydrophobic acrylic IOL was loaded in the injector for insertion into the capsular bag. During insertion, the IOL inadvertently extended into the corneal stromal lamella. The complication was recognized at a late stage, and the foldable acrylic lens was retrieved and reinserted correctly in the bag. The anterior chamber was made viscoelastically taut and was maintained in this state for 10 min, followed by a routine viscoelastic wash and air bubble injection. Cornea was slightly edematous with stromal haze, and the corneal thickness was 908 μm. At the 1-month follow-up visit, the patient′s vision was 20/40, the stromal haze had subsided, the corneal thickness was 572 μm, and the patient was comfortable. Though it was unknown complication, following proper management patient recovered satisfactorily.

  15. Weak Gravitational Lensing

    Science.gov (United States)

    Pires, Sandrine; Starck, Jean-Luc; Leonard, Adrienne; Réfrégier, Alexandre

    2012-03-01

    This chapter reviews the data mining methods recently developed to solve standard data problems in weak gravitational lensing. We detail the different steps of the weak lensing data analysis along with the different techniques dedicated to these applications. An overview of the different techniques currently used will be given along with future prospects. Until about 30 years ago, astronomers thought that the Universe was composed almost entirely of ordinary matter: protons, neutrons, electrons, and atoms. The field of weak lensing has been motivated by the observations made in the last decades showing that visible matter represents only about 4-5% of the Universe (see Figure 14.1). Currently, the majority of the Universe is thought to be dark, that is, does not emit electromagnetic radiation. The Universe is thought to be mostly composed of an invisible, pressure less matter - potentially relic from higher energy theories - called "dark matter" (20-21%) and by an even more mysterious term, described in Einstein equations as a vacuum energy density, called "dark energy" (70%). This "dark" Universe is not well described or even understood; its presence is inferred indirectly from its gravitational effects, both on the motions of astronomical objects and on light propagation. So this point could be the next breakthrough in cosmology. Today's cosmology is based on a cosmological model that contains various parameters that need to be determined precisely, such as the matter density parameter Omega_m or the dark energy density parameter Omega_lambda. Weak gravitational lensing is believed to be the most promising tool to understand the nature of dark matter and to constrain the cosmological parameters used to describe the Universe because it provides a method to directly map the distribution of dark matter (see [1,6,60,63,70]). From this dark matter distribution, the nature of dark matter can be better understood and better constraints can be placed on dark energy

  16. ATYPICAL CASE OF RETAINED INTRAOCULAR FOREIGN BODY PRESENTING AS SECONDARY GLAUCOMA AFTER 12 YEARS

    Directory of Open Access Journals (Sweden)

    Chandrakant

    2015-02-01

    Full Text Available Atypical case of retained intraocular foreign body presenting as secondary glaucoma after 12 years . To report a case of retained intraocular foreign body presenting as glaucoma after 12 yrs. A 24 yrs old male patient came to OPD, with pain & redness in right eye since 2 days. He was operated for cataract 12 years back. On examination, OD VA - hand movements. Slit lamp examination revealed corneal edema and deep anterior chamber . Rest of the det ails was not clear. OS Findings were normal. IOP: OD - 50 mmHg, OS - 16 mmHg. After control of IOP with medications, following findings were noted: Corneal scar in paracentral zone. RAPD present in right eye. Iris hole present at 3’0 clock position. FUNDUS: V itreous is clear. Intraocular foreign body of size half disc diameter present over the optic disc. Disc is pale , with attenuated vessels & peripapillary pigmentary changes. Yellowish speckled lesions present surrounding the vessels and dull foveal reflex. Gonioscopy revealed open angles with increased pigmentation. Visual fields showing advanced field defects . CT & B scan showing radio opaque foreign body over disc. Electro retinogram of right eye showing reduced response to all stimuli. Removal of foreign body not done because of poor visual prognosis & risk of symphathetic ophthalmitis. CONCLUSION: Retained metallic Intraocular foreign body can manifest after many years with varied presentation like secondary glaucoma without classical f eatures of siderosis bulbi .

  17. wire chamber

    CERN Multimedia

    Was used in ISR (Intersecting Storage Ring) split field magnet experiment. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  18. Biopsy techniques for intraocular tumors.

    Science.gov (United States)

    Rishi, Pukhraj; Dhami, Abhinav; Biswas, Jyotirmay

    2016-06-01

    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. PMID:27488148

  19. 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.

  20. Robert Chambers

    NARCIS (Netherlands)

    K. Biekart (Kees); D.R. Gasper (Des)

    2013-01-01

    textabstractProfessor Robert Chambers is a Research Associate at the Institute of Development Studies (IDS), University of Sussex (Brighton, UK), where he has been based for the last 40 years, including as Professorial Research Fellow. He became involved in the field of development management in the

  1. Weak gravitational lensing

    CERN Document Server

    Hoekstra, H

    2014-01-01

    Luminous tracers have been used extensively to map the large-scale matter distribution in the Universe. Similarly the dynamics of stars or galaxies can be used to estimate masses of galaxies and clusters of galaxies. However, assumptions need to be made about the dynamical state or how well galaxies trace the underlying dark matter distribution. The gravitational tidal ?field a?ffects the paths of photons, leading to observable e?ffects. This phenomenon, gravitational lensing, has become an important tool in cosmology because it probes the mass distribution directly. In these lecture notes we introduce the main relevant quantities and terminology, but the subsequent discussion is mostly limited to weak gravitational lensing, the small coherent distortion of the shapes of distant galaxies by intervening structures. We focus on some of the issues in measuring accurate shapes and review the various applications of weak gravitational lensing, as well as some recent results.

  2. Contact Lenses in the Laboratory.

    Science.gov (United States)

    Kingston, David W.

    1981-01-01

    Summarizes results of a three-item questionnaire returned by 43 Michigan institutions expressing views on wearing contact lenses in chemical laboratories. Questions focused on eye protection, type of protection, and use of contact lenses. (SK)

  3. Accuracy of Intraocular Lens Power Formulas Involving 148 Eyes with Long Axial Lengths: A Retrospective Chart-Review Study.

    Science.gov (United States)

    Chen, Chong; Xu, Xian; Miao, Yuyu; Zheng, Gaoxin; Sun, Yong; Xu, Xun

    2015-01-01

    Purpose. This study aims to compare the accuracy of intraocular lens power calculation formulas in eyes with long axial lengths from Chinese patients subjected to cataract surgery. Methods. A total of 148 eyes with an axial length of >26 mm from 148 patients who underwent phacoemulsification with intraocular lens implantation were included. The Haigis, Hoffer Q, Holladay 1, and SRK/T formulas were used to calculate the refractive power of the intraocular lenses and the postoperative estimated power. Results. Overall, the Haigis formula achieved the lowest level of median absolute error 1.025 D (P 33 mm, and median absolute errors were significantly higher for those eyes than eyes with axial length = 26.01-30.00 mm. Absolute error was correlated with axial length for the SRK/T (r = 0.212, P = 0.010) and Hoffer Q (r = 0.223, P = 0.007) formulas. For axial lengths > 33 mm, eyes exhibited a postoperative hyperopic refractive error. Conclusions. The Haigis and SRK/T formulas may be more suitable for calculating intraocular lens power for eyes with axial lengths ranging from 26 to 33 mm. And for axial length over 33 mm, the Haigis formula could be more accurate. PMID:26793392

  4. Posterior capsular opacification: Incidence and factors influencing and rate of Nd:YAG capsulotomy in diabetic and uveitic patients and after multifocal intraocular lens implantation.

    OpenAIRE

    Elgohary, M A

    2005-01-01

    This thesis examined the incidence and factors affecting the rate of posterior capsular opacification (PCX)), the most common complication of cataract surgery, in diabetic and uvcitic patients and in patients with multifocal intraocular lenses (IOLs). These patients arc particularly sensitive to PCO development because of the risks associated with Nd:YAG capsulotomy in the former two groups and the potential effect on visual function in the latter group. PCO rate was estimated both retrospect...

  5. Nonparaxial anamorphic diffractive lenses

    International Nuclear Information System (INIS)

    Applications of anamorphic diffractive lenses, or in other words elliptical zone plates, are growing in number and diversity. Following this progress, the manufacturing methods of anamorphic diffractive lenses are also a subject of continuous improvement. On the other hand, their design is still based mainly on the paraxial approximation. In the present paper nonparaxial elliptical zone plates are presented and their difference from the paraxial version, termed as the elliptical aberration is shown. A comparison of their focusing quality was performed based on results of numerical modelling as well as experiments. (paper)

  6. Gravitational Lensing & Stellar Dynamics

    CERN Document Server

    Koopmans, L V E

    2005-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and mass-anisotropy degeneracies. Second, observational results are presented from the Lenses Structure & Dynamics (LSD) Survey and the Sloan Lens ACS (SLACS) Survey collaborations to illustrate this new methodology in constraining the dark and stellar density profiles, and mass structure, of early-type galaxies to redshifts of unity.

  7. Weak and Strong Lensing Statistics

    OpenAIRE

    Straumann, Norbert

    2001-01-01

    After a brief introduction to gravitational lensing theory, a rough overview of the types of gravitational lensing statistics that have been performed so far will be given. I shall then concentrate on recent results of galaxy-galaxy lensing, which indicate that galactic halos extend much further than can be probed via rotation of stars and gas.

  8. Implantation of iris-claw Artisan intraocular lens for aphakia in Fuchs′ heterochromic iridocyclitis

    Directory of Open Access Journals (Sweden)

    Ahmad Kheirkhah

    2014-01-01

    Full Text Available Implantation of iris-claw Artisan intraocular lens (IOL is a surgical option for correction of aphakia; however, these IOLs have not been used in eyes with uveitis including Fuchs′ heterochromic iridocyclitis (FHI due to possible risk of severe postoperative intraocular inflammation. In the case reported here, we secondarily implanted an Artisan IOL in a 28-year-old man with FHI who had aphakia with no capsular support due to a previous complicated cataract surgery. Enclavation was easily performed and no intraoperative complication was noted. Postoperative course was uneventful with no significant anterior chamber inflammation during 12 months of follow-up. Although there were few deposits on the IOL surface, the patient achieved a best-corrected visual acuity of 20/20 without developing glaucoma or other complications. Therefore, Artisan IOL may be considered for correction of aphakia in patients with FHI. However, studies on large number of patients are required to evaluate safety of the procedure.

  9. Ionization chamber

    International Nuclear Information System (INIS)

    An ionization chamber X-ray detector is described. It comprises a flat cathode sheet parallel to an anode which has a perforated insulating layer on its surface. An open grid, a thin perforated metal sheet is disposed on the insulating layer - the perforations of the layer and sheet are aligned. There is a detector gas and means for maintaining the grid at an electric potential between that of the anode and cathode and for measuring the current flow from the anode to the cathode. The grid shields the anode from the electric field produced by the positive ions which flow towards the cathode and this permits an independent measurement of the electron current flowing to the anode; even when the X-ray pulse length is not much shorter than the ion drift time. The recovery time of the ionization chamber is thus decreased by several orders of magnitude over previous chambers. The grid will normally be fixed to the anode and by shielding the anode from the cathode electric field, tends to eliminate capacitive microphone currents which would otherwise flow in the anode circuit. (U.K.)

  10. 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... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens guide. 886.4300 Section...

  11. Personal radon dosimetry from eyeglass lenses

    International Nuclear Information System (INIS)

    Eyeglass lenses are commonly composed of allyl-diglycol carbonate (CR-39), an alpha-particle detecting plastic, thus making such lenses personal radon dosemeters. Samples of such lenses have been obtained, etched to reveal that radon and radon progeny alpha tracks can be seen in abundance, and sensitivities have been calibrated in radon chambers as a primary calibration, and with a uranium-based source of alpha particles as a convenient secondary standard. With one exception natural, environmental (fossil) track densities ranged from less than 3,000 to nearly 70,000 per cm2 for eyeglasses that had been worn for various times from one to nearly five years. Average radon concentrations to which those wearers were exposed are inferred to be in the range 14 to 130 Bq.m-3 (0.4 to 3.5 pCi.l-1). A protocol for consistent, meaningful readout is derived and used. In the exceptional case the fossil track density was 1,780,000 cm-2, and the inferred (24 h) average radon concentration was 6500 Bq.m-3 (175 pCi.l-1) for a worker at an inactive uranium mine that is used for therapy. (author)

  12. 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.

  13. Gold Nanoslit Lenses

    OpenAIRE

    Ishii, Satoshi; Kildishev, Alexander V.; Shalaev, Vladimir M.; Chen, Kuo-Ping; Drachev, Vladimir P.

    2011-01-01

    We experimentally demonstrate the focusing properties of arrays of parallel subwavelength-wide nanoslits in a gold film. The lenses are designed to focus either TM- or TE-polarized light and diverge the light of the orthogonal polarization. (C) 2010 Optical Society of America

  14. Feline intraocular sarcoma associated with phthisis bulbi

    Directory of Open Access Journals (Sweden)

    E. Perlmann

    2011-06-01

    Full Text Available Two cases of feline intraocular sarcoma were reported in stray cats that presented blindness and hypotonia of the affected eye for years before the tumor development. Phthisis bulbi, a final stage of a severe inflammation of the eye, is frequently unmonitored because eyes are blind, small, opaque, and not painful. Yet, this report shows that monitoring and early enucleation of eyes of cats with phthisis bulbi are important and should be considered as a treatment option, because feline intraocular sarcoma is an aggressive tumor that significantly decreases live expectancy.

  15. 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.

  16. The relationship between cytokine level and nitric oxide content in aqueous humor after intraocular lens implantation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM: To investigate the relationship between cytokine level and nitric oxide (NO) content in aqueous humor after intraocular lens implantation. METHODS: All New Zealand rabbits were divided randomly into three groups: (1) control group, (2) extracapsular cataract extraction group (ECCE), (3) extracapsular cataract extraction and posterior chamber intraocular lens implantation group (ECCE+IOL). The inflammation of all experimental rabbit eyes, including cornea edema and anterior chamber exudation were observed via zoom-photo slitlamp microscope 1,3,7,14,30 d postoperation. Meanwhile, aqueous humor was drawn for white blood cell (WBC) counting and classifying, and for NO-2/NO-3 and cytokine assay, including interleukin-2(IL-2), tumour necrosis factor-α(TNF-α). Statistics were taken by SPSS softwear. RESULTS: (1) Total WBC in aqueous humor were higher and anterior chamber exudation were more severe in ECCE+IOL group than that in ECCE group and control group. (2) The level of IL-2 and TNF-α and the content of NO-2/NO-3 in aqueous humor of ECCE+IOL group were higher than that in ECCE group and control group 1-14 d postoperation respectively, and it increased to peak value at 3-7 d postoperation and decreased gradually after two weeks postoperation. (3) The change regularity of IL-2, TNF-α and NO-2/NO-3 in each group were basically similar, i.e. when the level of cytokine (IL-2 and TNF-α) was normal, the content of NO-2/NO-3 was normal too, when the level of cytokine (IL-2 and TNF-α) increased, the content of NO-2/NO-3 increased too. CONCLUSION: The intraocular inflammation after ECCE+IOL was more severe than that after simple ECCE. NO, IL-2 and TNF-α play an important role in intraocular inflammation after intraocular lens implantation. The changes of IL-2 and TNF-α level was closely related with NO content in aqueous humor.

  17. Evaluation of a class of polyurethane materials for intraocular lens manufacturing.

    Science.gov (United States)

    Bozukova, Dimitriya; Bertrand, Virginie; Pagnoulle, Christophe; De Pauw-Gillet, Marie-Claire

    2015-08-01

    Ophthalmic lenses are medical devices with considerable requirements in terms of optical, biomechanical and biological performance. There is limited number of materials used for their manufacturing, comprising mainly silicones and poly(meth)acrylates. This series of publications aims at investigating the applicability of thermoplastic polyurethane elastomers (TPU) for the manufacturing of ophthalmic lenses and examining the properties of the respective devices. This study is related to the synthesis of TPUs with chemical compositions that comprise chemically grafted filters for the hazardous-light. GC-MS, attenuated total reflectance Fourier transform infrared spectroscopy, and UV-vis spectroscopies confirmed the reaction completion and the beneficial effect of the filters on the light transmittance, respectively. Relatively high refractive index of the material was measured and allows for the manufacturing of thinner lenses. The contrast sensitivity determined for a model intraocular lens (IOL) was satisfactory. Few optical defects were, however, present on the model lens prepared by thermoplastic injection molding. The elasticity of the materials was evaluated in view to their potential applicability as foldable IOLs by determining their glass transition temperature and their Young modulus and measuring their shore A. The TPU materials demonstrated more bioadhesive character compared with a benchmark hydrophilic acrylic reference material, which is already used for IOL manufacturing. PMID:25352276

  18. Learning unit: Thin lenses

    Science.gov (United States)

    Nita, L.-S.

    2012-04-01

    Learning unit: Thin lenses "Why objects seen through lenses are sometimes upright and sometimes reversed" Nita Laura Simona National College of Arts and Crafts "Constantin Brancusi", Craiova, Romania 1. GEOMETRIC OPTICS. 13 hours Introduction (models, axioms, principles, conventions) 1. Thin lenses (Types of lenses. Defining elements. Path of light rays through lenses. Image formation. Required physical quantities. Lens formulas). 2. Lens systems (Non-collated lenses. Focalless systems). 3. Human eye (Functioning as an optical system. Sight defects and their corrections). 4. Optical instruments (Characteristics exemplified by a magnifying glass. Paths of light rays through a simplified photo camera. Path of light rays through a classical microscope) (Physics curriculum for the IXth grade/ 2011). This scenario exposes a learning unit based on experimental sequences (defining specific competencies), as a succession of lessons started by noticing a problem whose solution assumes the setup of an experiment under laboratory conditions. Progressive learning of theme objectives are realised with sequential experimental steps. The central cognitive process is the induction or the generalization (development of new knowledge based on observation of examples or counterexamples of the concept to be learnt). Pupil interest in theme objectives is triggered by problem-situations, for example: "In order to better see small objects I need a magnifying glass. But when using a magnifier, small object images are sometimes seen upright and sometimes seen reversed!" Along the way, pupils' reasoning will converge to the idea: "The image of an object through a lens depends on the relative distances among object, lens, and observer". Associated learning model: EXPERIMENT Specific competencies: derived from the experiment model, in agreement with the following learning unit steps I. Evoking - Anticipation: Size of the problem, formulation of hypotheses and planning of experiment. II

  19. Characterizing intraocular tumors with photoacoustic imaging

    Science.gov (United States)

    Xu, Guan; Xue, Yafang; Gursel, Zeynep; Slimani, Naziha; Wang, Xueding; Demirci, Hakan

    2016-03-01

    Intraocular tumors are life-threatening conditions. Long-term mortality from uveal melanoma, which accounts for 80% of primary intraocular tumors, could be as high as 25% depending on the size, ciliary body involvement and extraocular extension. The treatments of intraocular tumors include eye-sparing approaches such as radiotherapy and thermotherapy, and the more aggressive enucleation. The accurate diagnosis of intraocular tumors is thereby critical in the management and follow-up of the patients. The diagnosis of intraocular tumors is usually based on clinical examination with acoustic backscattering based ultrasonography. By analyzing the high frequency fluctuations within the ultrasound (US) signals, microarchitecture information inside the tumor can be characterized. However, US cannot interrogate the histochemical components formulating the microarchitecture. One representative example is the inability of US imaging (and other contemporary imaging modalities as well) in differentiating nevoid and melanoma cells as the two types of cells possesses similar acoustic backscattering properties. Combining optical and US imaging, photoacoustic (PA) measurements encode both the microarchitecture and histochemical component information in biological tissue. This study attempts to characterize ocular tumors by analyzing the high frequency signal components in the multispectral PA images. Ex vivo human eye globes with melanoma and retinoblastoma tumors were scanned using less than 6 mJ per square centimeters laser energy with tunable range of 600-1700 nm. A PA-US parallel imaging system with US probes CL15-7 and L22-14 were used to acquire the high frequency PA signals in real time. Preliminary results show that the proposed method can identify uveal melanoma against retinoblastoma tumors.

  20. Pulsar lensing geometry

    CERN Document Server

    Liu, Siqi; Macquart, J-P; Brisken, Walter; Deller, Adam

    2015-01-01

    Our analysis of archival VLBI data of PSR 0834+06 revealed that its scintillation properties can be precisely modelled using the inclined sheet model (Pen & Levin 2014), resulting in two distinct lens planes. These data strongly favour the grazing sheet model over turbulence as the primary source of pulsar scattering. This model can reproduce the parameters of the observed diffractive scintillation with an accuracy at the percent level. Comparison with new VLBI proper motion results in a direct measure of the ionized ISM screen transverse velocity. The results are consistent with ISM velocities local to the PSR 0834+06 sight-line (through the Galaxy). The simple 1D structure of the lenses opens up the possibility of using interstellar lenses as precision probes for pulsar lens mapping, precision transverse motions in the ISM, and new opportunities for removing scattering to improve pulsar timing. We describe the parameters and observables of this double screen system. While relative screen distances can i...

  1. Anterior chamber gas bubbles in open globe injury.

    Science.gov (United States)

    Barnard, E B G; Baxter, D; Blanch, R

    2013-01-01

    We present a case of a 40-year-old soldier who was in close proximity to the detonation of an improvised explosive device (IED). Bubbles of gas were visible within the anterior chamber of his left eye. The authors propose that intraocular gas, present acutely after trauma, is diagnostic of open globe injury and is of particular importance in remote military environments. PMID:24079202

  2. Linguatula serrata in the anterior chamber of the eye

    Directory of Open Access Journals (Sweden)

    Muna Bhende

    2014-01-01

    Full Text Available We report a case of intraocular Linguatula in healthy young female who presented with a history of trivial trauma, dislocated lens, inflammation and secondary glaucoma. A mobile worm was seen in the anterior chamber. Pars plana lensectomy and vitrectomy was planned to remove both the cataractous lens and the parasite during which the worm disappeared from view but was later recovered from the cassette fluid. It was identified as the nymphal form of Linguatula serrata (tongue worm.

  3. Management of dislocated intraocular implants.

    Science.gov (United States)

    Chan, C K; Agarwal, A; Agarwal, S; Agarwal, A

    2001-12-01

    Implant dislocation may occur in the absence of appropriate capsular or zonular support (PCIOL) (11,35,53) or following traumatic injury to anterior ocular tissues (ACIOL). (11,19,20) Other factors (e.g., advanced patient age, high myopia, previous vitrectomy, pseudoexfoliation syndrome, and certain connective tissue disorders) also may predispose implant dislocation. (9,52) Although reported for all types of IOLs, implant dislocation is becoming more manageable because of the advancement of surgical techniques. A dislocated ACIOL or PCIOL may be explanted, exchanged, or repositioned. (11,48,71) Repositioning the dislocated PCIOL in the ciliary sulcus with modern vitreoretinal techniques provides an optimal environment for visual recovery. (11,71) Implant repositioning techniques generally may be categorized into the external or the internal approaches. (8,11) The former involves external suturing methods for a primary or secondary implant in the absence of adequate capsular or zonular support (15,16,31,42,56,60,61,64,66,73,76) and the latter is achieved through modern pars plana techniques. 8,11,62,69) Recently, several implant repositioning methods gaining increasing acceptance include the scleral loop fixation, (45) the snare approach, (43) the use of the 25-gauge implant forceps, (13) temporary haptic externalization, (8,11,36,71) and the use of perfluorocarbon liquids. (1,28,40,41,44) The temporary haptic externalization method combines the best features of the external and the internal approaches, avoids complex intraocular maneuvers, and allows precise scleral fixation of the dislocated IOL on a consistent basis. (8,11,71) Endoscopy provides the surgeon with optimal viewing of the anterior retropupillary anatomy that is often difficult to appreciate (e.g., capsular-zonular complex, ciliary sulcus, anterior retina, and vitreous base). (6,11) As a result, precise haptic placement is possible during the repositioning process. (6,11) However, a three

  4. Gravitational lensing by wormholes

    OpenAIRE

    Dey, Tushar Kanti; Sen, Surajit

    2008-01-01

    We have investigated the gravitational lensing by two wormholes, viz., Janis-Newman-Winnicour (JNW) wormhole and Ellis wormhole. The deflection angle in the strong field limit is calculated and various lens parameters of two wormholes are compared. It is shown that the JNW wormhole exhibits the relativistic images, while the Ellis wormhole does not have any relativistic images due to the absence of its photon sphere.

  5. Hydrogels contact lenses

    Czech Academy of Sciences Publication Activity Database

    Michálek, Jiří; Hobzová, Radka; Přádný, Martin; Dušková, Miroslava

    New York : Springer, 2010 - (Ottenbrite, R.; Park, K.; Okano, T.), s. 303-315 ISBN 978-1-4419-5918-8 R&D Projects: GA AV ČR KAN200520804 Institutional research plan: CEZ:AV0Z40500505 Keywords : contact lenses * hydrogels * silicone-hydrogels Subject RIV: EI - Biotechnology ; Bionics http://www.springerlink.com/content/l32kx3303v110unn/

  6. Noiseless Gravitational Lensing Simulations

    CERN Document Server

    Angulo, Raul E; Hilbert, Stefan; Abel, Tom

    2013-01-01

    The microphysical properties of the DM particle can, in principle, be constrained by the properties and abundance of substructures in DM halos, as measured through strong gravitational lensing. Unfortunately, there is a lack of accurate theoretical predictions for the lensing signal of substructures, mainly because of the discreteness noise inherent to N-body simulations. Here we present Recursive-TCM, a method that is able to provide lensing predictions with an arbitrarily low discreteness noise, without any free parameters or smoothing scale. This solution is based on a novel way of interpreting the results of N-body simulations, where particles simply trace the evolution and distortion of Lagrangian phase-space volume elements. We discuss the advantages of this method over the widely used cloud-in-cells and adaptive-kernel smoothing density estimators. Applying the new method to a cluster-sized DM halo simulated in warm and cold DM scenarios, we show how the expected differences in their substructure popul...

  7. Chamber transport

    Energy Technology Data Exchange (ETDEWEB)

    OLSON,CRAIG L.

    2000-05-17

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system.

  8. Measurement of intraocular distances in human eyes by using Fourier domain low-coherence interferometry

    Science.gov (United States)

    Feng, Liang; Zhu, Lida; Li, Qinghua; Ma, Zhenhe; Wang, Bo; Wang, Yi

    2016-03-01

    We introduce a system for rapidly measuring the intraocular distances of human eyes in vivo with high sensitivity by using Fourier domain low-coherence interferometry. The system mainly consisting of a rapid focus displacement unit and a reference arm which has a variable optical path length. This system is capable of providing a complete biometrical assessment of a human eye in a single measurement procedure, including cornea thickness, anterior chamber depth, lens thickness, and axial length. The system is experimentally verified by measuring the four parameters of a human eye in vivo.

  9. Intraocular lens power estimation by accurate ray tracing for eyes underwent previous refractive surgeries

    Science.gov (United States)

    Yang, Que; Wang, Shanshan; Wang, Kai; Zhang, Chunyu; Zhang, Lu; Meng, Qingyu; Zhu, Qiudong

    2015-08-01

    For normal eyes without history of any ocular surgery, traditional equations for calculating intraocular lens (IOL) power, such as SRK-T, Holladay, Higis, SRK-II, et al., all were relativley accurate. However, for eyes underwent refractive surgeries, such as LASIK, or eyes diagnosed as keratoconus, these equations may cause significant postoperative refractive error, which may cause poor satisfaction after cataract surgery. Although some methods have been carried out to solve this problem, such as Hagis-L equation[1], or using preoperative data (data before LASIK) to estimate K value[2], no precise equations were available for these eyes. Here, we introduced a novel intraocular lens power estimation method by accurate ray tracing with optical design software ZEMAX. Instead of using traditional regression formula, we adopted the exact measured corneal elevation distribution, central corneal thickness, anterior chamber depth, axial length, and estimated effective lens plane as the input parameters. The calculation of intraocular lens power for a patient with keratoconus and another LASIK postoperative patient met very well with their visual capacity after cataract surgery.

  10. Cross-correlating Planck CMB lensing with SDSS: Lensing-lensing and galaxy-lensing cross-correlations

    CERN Document Server

    Singh, Sukhdeep; Brownstein, Joel R

    2016-01-01

    We present first results from cross-correlating Planck CMB lensing maps with the Sloan Digital Sky Survey (SDSS) galaxy lensing shape catalog and BOSS galaxy catalogs. For galaxy position vs. CMB lensing cross-correlations, we measure the convergence signal around the galaxies in configuration space, using the BOSS LOWZ ($z\\sim0.30$) and CMASS ($z\\sim0.57$) samples. With fixed Planck 2015 cosmology, doing a joint fit with the galaxy clustering measurement, for the LOWZ (CMASS) sample we find a galaxy bias $b_g=1.75\\pm0.04$ ($1.95\\pm 0.02$) and galaxy-matter cross-correlation coefficient $r_{cc}=1.0\\pm0.2$ ($0.8\\pm 0.1$) using $20lensing. Using the same scales and including the galaxy-galaxy lensing measurements, we constrain $\\Omega_m=0.284\\pm0.024$ and relative calibration bias between the CMB lensing and galaxy lensing to be $b_\\gamma=0.82^{+0.15}_{-0.14}$. The combination of galaxy lensing and CMB lensing also allows us to measure the cosmolo...

  11. Distribution of pseudoexfoliation material on anterior segment structures in human autopsy eyes after cataract surgery with intraocular lens implantation.

    Science.gov (United States)

    Schmack, Ingo; Auffarth, Gerd Uwe

    2016-06-01

    The purpose of the study was to evaluate the distribution and amount of pseudoexfoliation material (PXM) on anterior segment structures in pseudophakic human autopsy eyes with pseudoexfoliation (PEX) syndrome and to study its impact on fixation and decentration of posterior chamber intraocular lenses (IOLs). Sixteen human autopsy eyes (donor age [mean ± SD] 77.5 ± 8.6 years; range, 70-90 years) with history of cataract surgery and PEX syndrome were analyzed for distribution and accumulation of PXM on structures of the anterior segment by light microscopy. Quantitative IOL decentration measurements were performed using the Miyake-Apple posterior view technique. All 16 eyes displayed IOLs which were either fixed symmetrically in the capsular bag (n = 8) or asymmetrically with one haptic in the sulcus and one in the bag (n = 7) or at the pars plicata of the ciliary body (n = 1). In the majority, PXM was found around the pars plicata (average grade: 1.6 ± 0.53 µm) and the lens capsule (average grade: 1.05 ± 0.46 µm). Minor amounts were detected at the pars plana and the trabecular meshwork. IOL decentration measurements ranged from 0.51 ± 0.35 (symmetrical-fixation) to 0.61 ± 0.43 mm (asymmetrical-fixation). There was only a weak statistically not significant correlation in regard to the amount of PXM and IOL decentration and between PXM distribution and the IOL fixation site. PXM contributes to weakening of the suspensory apparatus of the crystalline lens. Although PXM induced tissue alterations predispose for a broad spectrum of intra- and postoperative complications, the amount and distribution of PXM on different anterior segment structures showed only a weak correlation to IOL decentration or fixation location. PMID:26307751

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Extracapsular cataract extraction with posterior chamber lens implantation in Fuch's heterochromic cyclitis.

    OpenAIRE

    Baarsma, G.S.; Vries, J. de; Hammudoglu, C. D.

    1991-01-01

    Twenty-two patients with Fuch's heterochromic cyclitis had a posterior chamber intraocular lens implanted after extracapsular cataract extraction. After a mean follow-up period of 2.5 years (range, 6 to 70 months) half the patients had a visual acuity of 1.0 or more. The results compare favourably with those in the general population.

  14. Weak lensing by voids in modified lensing potentials

    CERN Document Server

    Barreira, Alexandre; Li, Baojiu; Baugh, Carlton; Pascoli, Silvia

    2015-01-01

    We study lensing by voids in Cubic Galileon and Nonlocal gravity cosmologies, which are examples of theories of gravity that modify the lensing potential. We find voids in the dark matter and halo density fields of N-body simulations and compute their lensing signal analytically from the void density profiles, which we show are well fit by a simple analytical formula. In the Cubic Galileon model, the modifications to gravity inside voids are not screened and they approximately double the size of the lensing effects compared to GR. The difference is largely determined by the direct effects of the fifth force on lensing and less so by the modified density profiles. For this model, we also discuss the subtle impact on the force and lensing calculations caused by the screening effects of haloes that exist in and around voids. In the Nonlocal model, the impact of the modified density profiles and the direct modifications to lensing are comparable, but they boost the lensing signal by only $\\approx 10\\%$, compared ...

  15. Microbiological profile of anterior chamber aspirates following uncomplicated cataract surgery

    Directory of Open Access Journals (Sweden)

    Prajna N

    1998-01-01

    Full Text Available Anterior chamber aspirate cultures were done for 66 patients who underwent either an uncomplicated intracapsular cataract extraction, extracapsular cataract extraction with posterior-chamber intraocular lens implantation, or phacoemulsification with posterior-chamber intraocular lens implantation. The aspirate was obtained at the time of wound closure. The aspirates were immediately transferred to the microbiology laboratory where one drop of the aspirate was placed on a glass slide for gram stain, and the remainder was unequally divided and inoculated into blood agar, chocolate agar and thioglycolate broth. The cultures were incubated at 37° C with 5% CO2 and held for 5 days. Of 66 patients 4 (6%, had smear-positive anterior chamber aspirates. None of the aspirates showed any growth on any of the 3 culture media used. None of the eyes in the study developed endophthalmitis. This study concludes that there is no contamination of the anterior chamber by viable bacteria after cataract surgery, irrespective of the mode of intervention.

  16. Intraocular pressure in Japanese diabetic patients

    OpenAIRE

    Matsuoka M; Ogata N.; Matsuyama K; Yoshikawa T.; Takahashi K.

    2012-01-01

    Masato Matsuoka,1 Nahoko Ogata,2 Kayako Matsuyama,1 Tadanobu Yoshikawa,1 Kanji Takahashi31Department of Ophthalmology, Kansai Medical University, Takii Hospital, Osaka, 2Department of Ophthalmology, Nara Medical University, Nara, 3Department of Ophthalmology, Kansai Medical University, Hirakata Hospital, Osaka, JapanBackground: To determine whether the intraocular pressure (IOP) in diabetic patients is significantly different from that in nondiabetic patients.Methods: The medical records of a...

  17. Intraocular eyelash after uneventful cataract surgery

    OpenAIRE

    Knyazer, Boris

    2010-01-01

    Boris Knyazer, Jaime Levy, Itamar Klemperer, Tova LifshitzDepartment of Ophthalmology, Soroka University Medical Center, Ben-Gurion, University of the Negev, Beer-Sheva, IsraelIntroduction: Intraocular eyelash is an uncommon complication after cataract surgery. We report a very rare case of corneal foreign body after uneventful phacoemulsification surgery. Methods: A 66-year-old man referred to our outpatient ophthalmology clinic for routine examination one week after uneventful phacoemulsifi...

  18. Roulettes: A weak lensing formalism for strong lensing - I. Overview

    CERN Document Server

    Clarkson, Chris

    2016-01-01

    We present a new perspective on gravitational lensing. We describe a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the non-linear geodesic deviation equation, the amplification matrix of weak lensing is generalised to a sum over independent amplification tensors of increasing rank. We show how an image distorted by a generic lens may be constructed as a sum over `roulettes', which are the natural curves associated with the independent spin modes of the amplification tensors. Highly distorted images can be constructed even for large sources observed near or within the Einstein radius of a lens where the shear and convergence are large. The amplitude of each roulette is formed from a sum over appropriate derivatives of the lensing potential. Consequently, measuring these individual roulettes for images around a lens gives a new way to reconstruct a strong lens mass distribution without requiring a lens model. This formalism generalises the convergence, ...

  19. 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.

  20. Effect of a tight necktie on intraocular pressure

    OpenAIRE

    Božić Marija; Hentova-Senćanin Paraskeva; Branković Aleksandra; Marjanović Ivan; Jocić Đorđević Jasmina; Senćanin Ivan

    2012-01-01

    Introduction. Any factor causing constriction of the neck may lead to an increase in intraocular pressure. A tight necktie may result in increasing intraocular pressure, which could lead to an erroneous diagnosis and treatment of ocular hypertension or even glaucoma. This study was aimed at evaluating the effect of a tight necktie on intraocular pressure measurement using Goldmann applanation tonometry. Material and Methods. This study included forty eyes of 20 patients with primary ope...

  1. 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...

  2. Heat Conduction in Lenses

    Directory of Open Access Journals (Sweden)

    Beat Aebischer

    2007-04-01

    Full Text Available We consider several heat conduction problems for glass lenses with different boundary conditions. The problems dealt with in Sections sec:1 to sec:3 are motivated by the problem of an airborne digital camera that is initially too cold and must be heated up to reach the required image quality. The problem is how to distribute the heat to the different lenses in the system in order to reach acceptable operating conditions as quickly as possible. The problem of Section sec:4 concerns a space borne laser altimeter for planetary exploration. Will a coating used to absorb unwanted parts of the solar spectrum lead to unacceptable heating? In this paper, we present analytic solutions for idealized cases that help in understanding the essence of the problems qualitatively and quantitatively, without having to resort to finite element computations. The use of dimensionless quantities greatly simplifies the picture by reducing the number of relevant parameters. The methods used are classical: elementary real analysis and special functions. However, the boundary conditions dictated by our applications are not usually considered in classical works on the heat equation, so that the analytic solutions given here seem to be new. We will also show how energy conservation leads to interesting sum formulae in connection with Bessel functions. The other side of the story, to determine the deterioration of image quality by given (inhomogeneous temperature distributions in the optical system, is not dealt with here.

  3. On Weak Lensing Shape Noise

    CERN Document Server

    Niemi, Sami-Matias; Cropper, Mark

    2015-01-01

    One of the most powerful techniques to study the dark sector of the Universe is weak gravitational lensing. In practice, to infer the reduced shear, weak lensing measures galaxy shapes, which are the consequence of both the intrinsic ellipticity of the sources and of the integrated gravitational lensing effect along the line of sight. Hence, a very large number of galaxies is required in order to average over their individual properties and to isolate the weak lensing cosmic shear signal. If this `shape noise' can be reduced, significant advances in the power of a weak lensing surveys can be expected. This paper describes a general method for extracting the probability distributions of parameters from catalogues of data using Voronoi cells, which has several applications, and has synergies with Bayesian hierarchical modelling approaches. This allows us to construct a probability distribution for the variance of the intrinsic ellipticity as a function of galaxy property using only photometric data, allowing a ...

  4. Gravitational lenses and cosmological evolution

    International Nuclear Information System (INIS)

    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)

  5. RETAINED STONE PIECE IN ANTERIOR CHAMBER

    Directory of Open Access Journals (Sweden)

    ZvornicaninJasmin, Nadarevic-VodencarevicAmra

    2015-04-01

    Full Text Available ABSTRACT We read with interest the article by Surekha et al. regarding the retained stone piece in anterior chamber. Similar to the results of previous studies, the authors found that delayed intraocular foreign body (IOFB management can result in good visual outcome without an apparent increased risk of endophthalmitis or other deleterious side effects. However, the authors failed to explain the exact reason for the diminution of vision in patients left eye. It is unclear what the uncorrected visual acuity was and what kind of correction was used, more precisely type and amount of cylinder, given the presence of the corneal opacity. Since the size of the IOFB is approximately 4x4x1mm, significant irido-corneal angle changes resulting in intraocular pressure raise and optic nerve head damage can be expected. Traumatic glaucoma following open globe injury can occur in 2.7 to 19% of cases, with several risk factors associated with glaucoma development (advanced age, poor visual acuity at presentation,perforating rather than penetrating ocular injury,lens injury, presence of vitreous hemorrhage and presence of an IOFB. Earlier reportsof latetraumaticoptic neuropathy onset, even after several years, indicate that this possibility cannot be completely ruled out too. Therefore, repeated intraocular pressure measurements, gonioscopy, pupillary reaction assessment, together with through posterior segment examination including visual field and optical coherence tomography examinations can be useful in determining the possible optic nerve damage as one of the possible reasons for visual acuity reduction. The authors did not suggest any operative treatment at this time. However, it should bear in mind that the inert anterior chamber IOFB could be a risk factor for non-infectious endophthalmitis development even after many years. Also, long term retained anterior chamber foreign body leads to permanent endothelial cell loss and can even result in a corneal

  6. A CLINICAL STUDY OF INTRAOCULAR PRESSURE CHANGES WITH VECURONIUM BROMIDE AND PANCURONIUM BROMIDE

    OpenAIRE

    Nagaraja; Nagesha

    2014-01-01

    BACKGROUND: The maintenance of intraocular pressure forms the mainstay of anesthetic management of intraocular surgery. It is desirable to achieve a normal or reduced intraocular pressure before the eye is opened to avoid expulsive hemorrhage and ocular disruption at the time of incision. Therefore the ideal anesthetic technique for intraocular surgery should produce a moderate reduction in intraocular pressure, or maintain intraocular pressure at near normal values and av...

  7. Iris Claw versus Scleral Fixation Intraocular Lens Implantation during Pars Plana Vitrectomy

    Directory of Open Access Journals (Sweden)

    Fereydoun Farrahi

    2012-01-01

    Full Text Available Purpose: To compare the outcomes of iris claw anterior chamber intraocular lens (ICACIOL with that of scleral fixation posterior chamber intraocular lens (SF-PCIOL implantation during pars plana vitrectomy (PPV as initial surgery to correct aphakia. Methods: Twelve patients with complicated cataract surgery or trauma who had suffered nucleus, whole crystalline lens or intraocular lens (IOL drop into the vitreous cavity, and undergone PPV with IC-ACIOL implantation over a period of one year were evaluated for the purpose of this study. Uncorrected visual acuity (UCVA, best corrected visual acuity (BCVA, central corneal thickness (CCT, spherical equivalent (SE refractive error, astigmatism and complications were recorded. The results were compared to outcomes of another group of 13 patients who had previously undergone PPV with SF-PCIOL implantation. Results: Mean improvement of UCVA was greater in IC-ACIOL eyes as compared to the SF-PCIOL group (-1.17±0.28 versus -0.89±0.21 logMAR, P=0.01, corresponding values for postoperative BCVA were 0.24±0.17 and 0.44±0.22 logMAR (P=0.041, respectively. Average postoperative SE was comparable in the IC-ACIOL and SFPCIOL groups at 0.6±1.03 and 0.56±1.23 diopters, respectively (P=0.290. However, 10 (83.3% IC-ACIOL eyes versus 6 (46.1% SF-PCIOL eyes had SE within 1 diopter of emmetropia (P=0.048. Mean postoperative increase in CCT was comaparble between the study groups (P=0.126. Conclusion: In the absence of sufficient capsular support, the use of an IC-ACIOL for correction of aphakia during PPV can be a good alternative and seems to entail better visual outcomes as compared to SF-PCIOL.

  8. Roulettes: a weak lensing formalism for strong lensing: I. Overview

    Science.gov (United States)

    Clarkson, Chris

    2016-08-01

    We present a new perspective on gravitational lensing. We describe a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the nonlinear geodesic deviation equation, the amplification matrix of weak lensing is generalised to a sum over independent amplification tensors of increasing rank. We show how an image distorted by a generic lens may be constructed as a sum over ‘roulettes’, which are the natural curves associated with the independent spin modes of the amplification tensors. Highly distorted images can be constructed even for large sources observed near or within the Einstein radius of a lens where the shear and convergence are large. The amplitude of each roulette is formed from a sum over appropriate derivatives of the lensing potential. Consequently, measuring these individual roulettes for images around a lens gives a new way to reconstruct a strong lens mass distribution without requiring a lens model. This formalism generalises the convergence, shear and flexion of weak lensing to arbitrary order, and provides a unified bridge between the strong and weak lensing regimes. This overview paper is accompanied by a much more detailed paper II, arXiv:1603.04652.

  9. 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.

  10. Dosimetry and treatment planning of Occu-Prosta I-125 seeds for intraocular lesions

    Directory of Open Access Journals (Sweden)

    Chaudhari Suresh

    2008-01-01

    Full Text Available Intraocular malignant lesions are frequently encountered in clinical practice. Plaque brachytherapy represents an effective means of treatment for intraocular lesions. Recently Radiopharmaceutical Division, BARC, Mumbai, has indigenously fabricated reasonable-cost I-125 sources. Here we are presenting the preliminary experience of dosimetry of sources, configuration of treatment planning system (TPS and quality assurance (QA for eye plaque therapy with Occu-Prosta I-125 seeds, treated in our hospital, for a patient with ocular lesions. I-125 seeds were calibrated using well-type chamber. BrachyVision TPS was configured with Monte Carlo computed radial dose functions and anisotropy functions for I-125 sources. Dose calculated by TPS at different points in central axis and off axis was compared with manually calculated dose. Eye plaque was fabricated of 17 karat pure gold, locally. The seeds were arranged in an outer ring near the edge of the plaque and in concentric rings throughout the plaque. The sources were manually digitized on the TPS, and dose distribution was calculated in three dimensions. Measured activity using cross-calibrated well-type chamber was within ±10% of the activity specified by the supplier. Difference in TPS-calculated dose and manually calculated dose was within 5%. Treatment time calculated by TPS was in concordance with published data for similar plaque arrangement.

  11. Dosimetry and treatment planning of Occu-Prosta I-125 seeds for intraocular lesions.

    Science.gov (United States)

    Chaudhari, Suresh; Deshpande, Sudesh; Anand, Vivek; De, Sandeep; Saxena, Sanjay; Dash, A; Basu, Mahua; Samant, Preetam; Kannan, V

    2008-01-01

    Intraocular malignant lesions are frequently encountered in clinical practice. Plaque brachytherapy represents an effective means of treatment for intraocular lesions. Recently Radiopharmaceutical Division, BARC, Mumbai, has indigenously fabricated reasonable-cost I-125 sources. Here we are presenting the preliminary experience of dosimetry of sources, configuration of treatment planning system (TPS) and quality assurance (QA) for eye plaque therapy with Occu-Prosta I-125 seeds, treated in our hospital, for a patient with ocular lesions. I-125 seeds were calibrated using well-type chamber. BrachyVision TPS was configured with Monte Carlo computed radial dose functions and anisotropy functions for I-125 sources. Dose calculated by TPS at different points in central axis and off axis was compared with manually calculated dose. Eye plaque was fabricated of 17 karat pure gold, locally. The seeds were arranged in an outer ring near the edge of the plaque and in concentric rings throughout the plaque. The sources were manually digitized on the TPS, and dose distribution was calculated in three dimensions. Measured activity using cross-calibrated well-type chamber was within +/-10% of the activity specified by the supplier. Difference in TPS-calculated dose and manually calculated dose was within 5%. Treatment time calculated by TPS was in concordance with published data for similar plaque arrangement. PMID:20041047

  12. Dosimetry and treatment planning of Occu-Prosta 125I seeds for intraocular lesions

    International Nuclear Information System (INIS)

    Intraocular malignant lesions are frequently encountered in clinical practice. Plaque brachytherapy represents an effective means of treatment for intraocular lesions. Recently Radiopharmaceutical Division, BARC, Mumbai, has indigenously fabricated reasonable-cost 125I sources. Here we are presenting the preliminary experience of dosimetry of sources, configuration of treatment planning system (TPS) and quality assurance (QA) for eye plaque therapy with Occu-Prosta 125I seeds, treated in our hospital, for a patient with ocular lesions. 125I seeds were calibrated using well-type chamber. BrachyVision TPS was configured with Monte Carlo computed radial dose functions and anisotropy functions for 125I sources. Dose calculated by TPS at different points in central axis and off axis was compared with manually calculated dose. Eye plaque was fabricated of 17 karat pure gold, locally. The seeds were arranged in an outer ring near the edge of the plaque and in concentric rings throughout the plaque. The sources were manually digitized on the TPS, and dose distribution was calculated in three dimensions. Measured activity using cross-calibrated well-type chamber was within ± 10% of the activity specified by the supplier. Difference in TPS-calculated dose and manually calculated dose was within 5%. Treatment time calculated by TPS was in concordance with published data for similar plaque arrangement. (author)

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

    DEFF Research Database (Denmark)

    Kessel, Line; Andresen, Jens; Tendal, Britta; Erngaard, Ditte; Flesner, Per; Hjortdal, Jesper

    2016-01-01

    evaluated as surgical complications and residual astigmatism. CLINICAL RELEVANCE: Postoperative astigmatism is an important cause of suboptimal UCDVA and need for distance spectacles. Toric IOLs may correct for preexisting corneal astigmatism at the time of surgery. METHODS: We performed a systematic...... literature search in the Embase, PubMed, and CENTRAL databases within the Cochrane Library. We included randomized clinical trials (RCTs) if they compared toric with non-toric IOL implantation (± relaxing incision) in patients with regular corneal astigmatism and age-related cataracts. We assessed the risk.......36-0.71) and moderate quality evidence that toric IOL implantation was not associated with an increased risk of complications (RR, 1.73; 95% CI, 0.60-5.04). Residual astigmatism was lower in the toric IOL group than in the non-toric IOL plus relaxing incision group (mean difference, 0.37 diopter [D]; 95% CI...

  14. The correction of corneal astigmatism of toric intraocular lenses in patients who underwent cataract surgery. Review

    OpenAIRE

    G. A. Fedyashev

    2014-01-01

    The paper presents an overview of the methods of surgical correction of corneal astigmatism in patients who underwent cataract surgery with IOL implantation, gives an idea of toric IOL, their advantages over other methods of the astigmatism correction, the criteria for patient selection, calculation features, preoperative marking. Besides the concept of rotational instability is sanctified position the IOL within the eye, its causes, methods of detecting the position of the IOL, as well as su...

  15. The correction of corneal astigmatism of toric intraocular lenses in patients who underwent cataract surgery. Review

    Directory of Open Access Journals (Sweden)

    G. A. Fedyashev

    2014-07-01

    Full Text Available The paper presents an overview of the methods of surgical correction of corneal astigmatism in patients who underwent cataract surgery with IOL implantation, gives an idea of toric IOL, their advantages over other methods of the astigmatism correction, the criteria for patient selection, calculation features, preoperative marking. Besides the concept of rotational instability is sanctified position the IOL within the eye, its causes, methods of detecting the position of the IOL, as well as surgical ways to improve its rotational stability.

  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. Recent Advances in Cataract Operations: Phacoemulsification, Intraocular Lens Implantation and Prolonged-Wear Soft Contact Lenses

    OpenAIRE

    Salz, James J.

    1981-01-01

    A standard cataract extraction involves removal of the entire cataractous lens through a 12- to 13-mm incision with the aid of a cryoprobe while phacoemulsification consists of removing the cataract through a 3-mm incision by breaking the lens into small pieces with an ultrasonically vibrating needle which is then used to aspirate the fragmented cataract. Most ophthalmic surgeons choose to carry out the standard cataract extraction because although phacoemulsification offers a more rapid reha...

  18. Influence of age, corneal astigmatism and some characteristics of intraocular lens on glare in pseudophakic persons

    Directory of Open Access Journals (Sweden)

    Avramović Siniša

    2007-01-01

    Full Text Available Background/Aim. Although an extraordinary visual acuity is achieved following the extracapsular cataract extraction with the implantation of intraocular lens, all the problems of vision are not solved in so doing and many of them should be considered. The aim of this study was to establish the influence of age, dioptric power of intraocular lens, corneal astigmatism and optic diameter of intraocular lens on glare in pseudophakic subjects. Methods. We examined 152 patients who underwent final correction at least two weeks after the suture removing what was performed if the astigmatism more than 2.0 D was measured by the use of a Javal keratometer. Examination was performed by a Rodenstock Adaptometer Nyctomat. According to the recommendation of the manufacturer, healthy persons should notice 50% of contrast under the constant glare and in the given time. Statistical data processing was performed by χ2 test. Results. In the group of patients with the findings lower than normal at constant glare there were 112 of eyes (73.68% as follows: 22 eyes (14.47% at the age from 50-55 years; 15 eyes (9.87% were at the age from 56-60 years; 18 eyes (11.84% were at the age from 61-65 years, and 57 eyes (37.50% were at the age from 66-70 years. Dioptric power of lenses up to 20.0 D had 37 eyes (24.3%, from 20.5-22.0 D 85 eyes (56.9% and more than 22.5 D, 27 eyes (17.8%. Regarding the results of discomfort caused by glare and corneal astigmatism, measured by a Javal keratometer, in the observed group normal results were found in 112 eyes (73.68%, and out of that number 95 (62.50% were with corneal astigmatism less than 20.0 D, and 17 (11.18% had astigmatism of 20.0 D and more. Out of 112 eyes there were 58 of them (38.16% with findings lower than normal in relation to the constant glare and with the lens diameter of 5.5 mm, 48 (31.58% with the lens diameter of 6.0mm, and 6 of them (3.95% with lens diameter of 6.5mm. Conclusion. The study determined a

  19. Directed Energy Anechoic Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — The Directed Energy Anechoic Chamber comprises a power anechoic chamber and one transverse electromagnetic cell for characterizing radiofrequency (RF) responses of...

  20. [Laser scan microscopy: a new imaging procedure in quality assessment of artificial lenses].

    Science.gov (United States)

    Rochels, R; Ziegler, E

    1989-01-01

    Laser-scan microscopy permits the evaluation of surfaces and deeper layers of an object by computer-assisted scanning with a laser beam. The reflected helium-neon or argon laser light is transmitted to a photodetector and after signal processing, to a frame store and a TV monitor. Imaging is realized by synchronous scanning and modulation of light intensity. Laser-scan microscopy revealed a smooth surface of both PMMA and HEMA lenses, whereas tears were detected in folded silicone implants. The physical and chemical homogeneity inside the three different materials was optimal. Compared to scanning electron microscopy, the quality of imaging is not as good with laser-scan microscopy. Nevertheless, one decisive advantage of the latter method is an analysis free of processing and artifacts, which permits a routine control of brand new and folded intraocular lenses. PMID:2722098

  1. 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.

  2. How to measure intraocular pressure: applanation tonometry

    Directory of Open Access Journals (Sweden)

    Nick Astbury

    2012-01-01

    Full Text Available Unless there is a contraindication (e.g. trauma or corneal ulcer, all adults attending an eye unit should have their intraocular pressure (IOP measured. Many people with glaucoma have no symptoms and do not know they have the condition. All children who have had cataract surgery should also have their IOP measured at every follow-up visit, if possible. Finding glaucoma early allows treatment to be given which will preserve sight. Although elevated IOP is not the only sign of glaucoma, measuring it is simple and quick to do. Applanation tonometry, using a Goldmann tonometer at a slit lamp, is the preferred method (the ‘gold standard’.

  3. Lensed: a code for the forward reconstruction of lenses and sources from strong lensing observations

    CERN Document Server

    Tessore, Nicolas; Metcalf, R Benton

    2015-01-01

    Robust modelling of strong lensing systems is fundamental to exploit the information they contain about the distribution of matter in galaxies and clusters. In this work, we present Lensed, a new code which performs forward parametric modelling of strong lenses. Lensed takes advantage of a massively parallel ray-tracing kernel to perform the necessary calculations on a modern graphics processing unit (GPU). This makes the precise rendering of the background lensed sources much faster, and allows the simultaneous optimisation of tens of parameters for the selected model. With a single run, the code is able to obtain the full posterior probability distribution for the lens light, the mass distribution and the background source at the same time. Lensed is first tested on mock images which reproduce realistic space-based observations of lensing systems. In this way, we show that it is able to recover unbiased estimates of the lens parameters, even when the sources do not follow exactly the assumed model. Then, we...

  4. Acoustic Fresnel lenses with extraordinary transmission

    OpenAIRE

    Molerón, Miguel; Serra-Garcia, Marc; Daraio, Chiara

    2014-01-01

    We investigate numerically and experimentally highly efficient acoustic lenses based on the principle of extraordinary acoustic transmission. We study circular, flat lenses composed of perforated air channels. The geometry is similar to binary Fresnel lenses, and the lenses exploit several resonance mechanisms to enhance the transmission, such as Fabry–Perot resonances in the channels and cavity resonances on the lens surface. The proposed lenses are able to transmit up to 83% of the incident...

  5. On Perfect Lenses and Nihility

    CERN Document Server

    Lakhtakia, A

    2002-01-01

    The canonical problem of a perfect lens with linear bianisotropic materials is formulated. Its solution is shown to be directly connected with the concept of nihility, the electromagnetic nilpotent. Perfect lenses as well as nihility remain unrealizable.

  6. Planar Lenses at Visible Wavelengths

    CERN Document Server

    Khorasaninejad, Mohammadreza; Devlin, Robert C; Oh, Jaewon; Zhu, Alexander Y; Capasso, Federico

    2016-01-01

    Sub-wavelength resolution imaging requires high numerical aperture (NA) lenses, which are bulky and expensive. Metasurfaces allow the miniaturization of conventional refractive optics into planar structures. We show that high-aspect-ratio titanium dioxide metasurfaces can be fabricated and designed as meta-lenses with NA = 0.8. Diffraction-limited focusing is demonstrated at wavelengths of 405 nm, 532 nm, and 660 nm with corresponding efficiencies of 86%, 73%, and 66%. The meta-lenses can resolve nanoscale features separated by sub-wavelength distances and provide magnification as high as 170x with image qualities comparable to a state-of-the-art commercial objective. Our results firmly establish that meta-lenses can have widespread applications in laser-based microscopy, imaging, and spectroscopy.

  7. HUBBLE'S TOP TEN GRAVITATIONAL LENSES

    Science.gov (United States)

    2002-01-01

    The NASA Hubble Space Telescope serendipitous survey of the sky has uncovered exotic patterns, rings, arcs and crosses that are all optical mirages produced by a gravitational lens, nature's equivalent of having giant magnifying glass in space. Shown are the top 10 lens candidates uncovered in the deepest 100 Hubble fields. Hubble's sensitivity and high resolution allow it to see faint and distant lenses that cannot be detected with ground-based telescopes whose images are blurred by Earth's atmosphere. [Top Left] - HST 01248+0351 is a lensed pair on either side of the edge-on disk lensing galaxy. [Top Center] - HST 01247+0352 is another pair of bluer lensed source images around the red spherical elliptical lensing galaxy. Two much fainter images can be seen near the detection limit which might make this a quadruple system. [Top Right] - HST 15433+5352 is a very good lens candidate with a bluer lensed source in the form of an extended arc about the redder elliptical lensing galaxy. [Middle Far Left] - HST 16302+8230 could be an 'Einstein ring' and the most intriguing lens candidate. It has been nicknamed the 'the London Underground' since it resembles that logo. [Middle Near Left] - HST 14176+5226 is the first, and brightest lens system discovered in 1995 with the Hubble telescope. This lens candidate has now been confirmed spectroscopically using large ground-based telescopes. The elliptical lensing galaxy is located 7 billion light-years away, and the lensed quasar is about 11 billion light-years distant. [Middle Near Right] - HST 12531-2914 is the second quadruple lens candidate discovered with Hubble. It is similar to the first, but appears smaller and fainter. [Middle Far Right] - HST 14164+5215 is a pair of bluish lensed images symmetrically placed around a brighter, redder galaxy. [Bottom Left] - HST 16309+8230 is an edge-on disk-like galaxy (blue arc) which has been significantly distorted by the redder lensing elliptical galaxy. [Bottom Center] - HST 12368

  8. Retropupillary iris-claw intraocular lens in ectopia lentis in Marfan syndrome

    Science.gov (United States)

    Faria, Mun Yueh; Ferreira, Nuno; Neto, Eliana

    2016-01-01

    Objective To report visual outcomes, complication rate, and safety of retropupillary iris-claw intraocular lens (ICIOL) in ectopia lentis in Marfan syndrome (MFS). Design Retrospective study. Methods Six eyes of three MFS patients with ectopia lentis underwent surgery for subluxation lens and retropupillary ICIOL implantation from October 2014 to October 2015 at the Department of Ophthalmology, Santa Maria Hospital in Lisbon, Portugal. Demographics, preoperative and postoperative best-corrected visual acuity (BCVA), and intraocular pressure were evaluated. Endothelium cell count was assessed using specular microscopy; anterior chamber depth was measured using Pentacam postoperatively; and intraocular lens position was viewed by ultrasound biomicroscopy. All patients were female; mean age was 20±14.264 years (range: 7–38 years). Results The average follow-up period was 6.66 months (range: 4–16 months). Preoperative BCVA was 0.568±0.149 logMAR units, and postoperative BCVA was 0.066±0.121 logMAR units. The mean BCVA gain was −0.502±0.221 on the logMAR scale. Postoperative average astigmatism and intraocular pressure were 1.292±0.697 mmHg (range: 0.5–2.25 mmHg) and 16 mmHg (range: 12–18 mmHg), respectively. The average endothelial cell density decreased from 3,121±178 cells/mm2 before surgery to 2,835±533 cells/mm2 after surgery (measured at last follow-up visit) and in the last follow-up, representing an average endothelial cell loss of 9.16%. Mean anterior chamber depth was 4.01 mm (±0.77 mm), as measured by Pentacam. No complications were found intra- or postoperatively in any of the six studied eyes. Conclusion Retropupillary ICIOL implantation is a safe and effective procedure in the treatment of aphakia in MFS eyes, without capsular support after surgery for ectopia lens. The six eyes that underwent lensectomy and retropupillary ICIOL implantation have had excellent visual outcomes with no complications so far. PMID:27382335

  9. Avaliação de lente intra-ocular fácica para a correção da presbiopia Phakic intraocular lens for presbyopia correction

    Directory of Open Access Journals (Sweden)

    Caroline Amaral Ferraz

    2007-08-01

    Full Text Available OBJETIVO: Avaliar os resultados clínicos e refrativos, bem como as complicações pós-operatórias, da cirurgia de implante de uma lente fácica multifocal de suporte angular para a correção da presbiopia. MÉTODOS: Estudo retrospectivo de análise de prontuários de 30 pacientes dos quais 51 olhos foram submetidos a implante de lente intra-ocular fácica Newlife® para a correção da presbiopia. Os pacientes foram avaliados em visita pré-operatória e em um mês, 3, 6 e 12 meses após a cirurgia. A análise descritiva das variáveis do estudo e os testes estatísticos foram realizados e as complicações pós-operatórias foram descritas. RESULTADOS: Após o procedimento, o equivalente esférico médio foi de -0,046 (± 0,48 D e 87,5% dos pacientes podiam ler P3 (equivalente a J2 sem necessidade de óculos. A perda de células endoteliais, após seguimento de 12 meses, foi de 7,57%. A lente intra-ocular foi retirada em 6 (11,5% olhos por diferentes razões, sendo a catarata a causa mais freqüente de retirada de lente. CONCLUSÕES: O implante da lente intra-ocular fácica Newlife® para a correção da presbiopia melhorou significativamente a acuidade visual sem correção e a refratometria no grupo de olhos estudados. Os critérios de avaliação adotados (acuidade visual com correção, contagem endotelial e existência de complicações não permitiram afirmar a segurança do procedimento de implante da lente intra-ocular fácica Newlife® para o período de acompanhamento analisado.PURPOSE: To evaluate clinical and refractive results of anterior chamber multifocal phakic intraocular lens Newlife® for presbyopia correction considering uncorrected far and near visual acuity and refraction data and also to evaluate safety of this intraocular lens considering distance and near corrected visual acuity, endothelial cell count and complications. METHODS: Retrospective analysis of a clinical database of 30 patients (51 eyes who had received

  10. Ocular Toxicity after High-Dose Cefuroxime Injection into the Anterior Chamber

    Directory of Open Access Journals (Sweden)

    Harun Çakmak

    2016-08-01

    Full Text Available Cephalosporins are beta-lactam antibiotics and, like penicillin derivatives, they show bacteriostatic effect by disrupting bacterial cell wall synthesis. Cefuroxime is a second generation cephalosporin and the use of intracameral cefuroxime after cataract surgery has been widely used in the endophthalmitis prophylaxis. A 78-year-old male patient was operated for cataracts in both eyes about 8 years ago. Ocular trauma has occurred in the left eye nine months ago. Vitrectomy surgery combined with intraocular lens extraction was performed and the patient was left aphakic. Secondary intraocular lens implantation was performed. In this paper, we present postoperative ocular findings in a patient who was given cefuroxime into the anterior chamber 2.5 times higher than the recommended dose (25 mg/ml after secondary intraocular lens implantation.

  11. Effect of a tight necktie on intraocular pressure

    Directory of Open Access Journals (Sweden)

    Božić Marija

    2012-01-01

    Full Text Available Introduction. Any factor causing constriction of the neck may lead to an increase in intraocular pressure. A tight necktie may result in increasing intraocular pressure, which could lead to an erroneous diagnosis and treatment of ocular hypertension or even glaucoma. This study was aimed at evaluating the effect of a tight necktie on intraocular pressure measurement using Goldmann applanation tonometry. Material and Methods. This study included forty eyes of 20 patients with primary open angle glaucoma and 20 healthy controls (all male. Intraocular pressure was measured without a necktie, 3 minutes after placing a tight necktie and 3 minutes after loosening it. Student’s t-test was used to analyze the data between two groups. The intraocular pressure measurements were subjected to paired t - test. The value p < 0.05 was considered statistically significant. A possible correlation between the age of subjects and intraocular pressure values was analyzed using linear regression (Pearson′. Results. A statistically significant difference was found in intraocular pressure readings in all three measurements between two tested groups (p<0.05. When analyzed within groups, statistical significance in intraocular pressure readings was found after loosening the necktie (<0.05. No correlation between the age of subjects and increased intraocular pressure was found in either tested group of subjects after the necktie had been tightened (r2=0.006, p=0.70 for primary open angle patients, r2=0.07, p=0.22 for healthy controls. Conclusion. Wearing a tight necktie for a limited period of time during the day could be considered as a possible risk factor for glaucoma development.

  12. 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

  13. 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.

  14. Effects of Cataract Surgery on Intraocular Pressure in Patients with and without Glaucoma

    Directory of Open Access Journals (Sweden)

    Tülin İsmi

    2013-06-01

    Full Text Available Pur po se: To evaluate the effects of phacoemulsification surgery with primary intraocular lens (IOL implantation on intraocular pressure (IOP in various types of glaucoma patients with visually significant cataract and to compare these results with cataract patients without glaucoma. Ma te ri al and Met hod: This retrospective study included consecutive cases of 21 primary open-angle glaucoma patients, 13 primary angle-closure glaucoma (PACG patients, 11 pseudoexfoliation glaucoma patients, and 21 control eyes without any type of glaucoma; all patients had co-existing cataract. Visual acuities, IOP, number of glaucoma medications used, anterior chamber depth (ACD, and gonioscopic evaluations were noted both pre- and postoperatively. Phacoemulsification and IOL implantations were performed via clear corneal incisions in the whole study group. Study group was followed-up for six months. Re sults: Postoperative visits at the 1st, 3rd, and 6th months were noted. After surgery, visual acuities improved significantly (p=0.001 in all groups. Intraocular pressures decreased in all groups postoperatively, but the change was statistically significant in the PACG group (p=0.013. Increase in ACD was significant in PACG group (p=0.001. Widening of iridocorneal angle and decrease in the number of antiglaucoma drugs were observed in all groups, but these were significant in the PACG group (p=0.001 and p<0.05, respectively. Dis cus si on: In glaucoma patients with co-existing cataract, phacoemulsification surgery allows both the visual rehabilitation and IOP control. This IOP lowering effect is seen most markedly in the PACG group. (Turk J Ophthalmol 2013; 43: 167-72

  15. Broken intraocular lens during cataract surgery.

    OpenAIRE

    Kirkpatrick, J N; Cook, S D

    1992-01-01

    A case of planned routine extracapsular cataract extraction is described where surgery was complicated peroperatively by fracture of the posterior chamber lens implant. The technique of lens implantation is discussed.

  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. Surface gravity-wave lensing.

    Science.gov (United States)

    Elandt, Ryan B; Shakeri, Mostafa; Alam, Mohammad-Reza

    2014-02-01

    Here we show that a nonlinear resonance between oceanic surface waves caused by small seabed features (the so-called Bragg resonance) can be utilized to create the equivalent of lenses and curved mirrors for surface gravity waves. Such gravity wave lenses, which are merely small changes to the seafloor topography and therefore are surface noninvasive, can focus or defocus the energy of incident waves toward or away from any desired focal point. We further show that for a broadband incident wave spectrum (i.e., a wave group composed of a multitude of different-frequency waves), a polychromatic topography (occupying no more than the area required for a monochromatic lens) can achieve a broadband lensing effect. Gravity wave lenses can be utilized to create localized high-energy wave zones (e.g., for wave energy harvesting or creating artificial surf zones) as well as to disperse waves in order to create protected areas (e.g., harbors or areas near important offshore facilities). In reverse, lensing of oceanic waves may be caused by natural seabed features and may explain the frequent appearance of very high amplitude waves in certain bodies of water. PMID:25353576

  18. Cosmology with weak lensing surveys.

    Science.gov (United States)

    Munshi, Dipak; Valageas, Patrick

    2005-12-15

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening mass. Since the lensing effects arise from deflections of the light rays due to fluctuations of the gravitational potential, they can be directly related to the underlying density field of the large-scale structures. Weak gravitational surveys are complementary to both galaxy surveys and cosmic microwave background observations as they probe unbiased nonlinear matter power spectra at medium redshift. Ongoing CMBR experiments such as WMAP and a future Planck satellite mission will measure the standard cosmological parameters with unprecedented accuracy. The focus of attention will then shift to understanding the nature of dark matter and vacuum energy: several recent studies suggest that lensing is the best method for constraining the dark energy equation of state. During the next 5 year period, ongoing and future weak lensing surveys such as the Joint Dark Energy Mission (JDEM; e.g. SNAP) or the Large-aperture Synoptic Survey Telescope will play a major role in advancing our understanding of the universe in this direction. In this review article, we describe various aspects of probing the matter power spectrum and the bi-spectrum and other related statistics with weak lensing surveys. This can be used to probe the background dynamics of the universe as well as the nature of dark matter and dark energy. PMID:16286284

  19. Intraocular pressure in Japanese diabetic patients

    Directory of Open Access Journals (Sweden)

    Matsuoka M

    2012-07-01

    Full Text Available Masato Matsuoka,1 Nahoko Ogata,2 Kayako Matsuyama,1 Tadanobu Yoshikawa,1 Kanji Takahashi31Department of Ophthalmology, Kansai Medical University, Takii Hospital, Osaka, 2Department of Ophthalmology, Nara Medical University, Nara, 3Department of Ophthalmology, Kansai Medical University, Hirakata Hospital, Osaka, JapanBackground: To determine whether the intraocular pressure (IOP in diabetic patients is significantly different from that in nondiabetic patients.Methods: The medical records of all patients who were initially examined in the Department of Ophthalmology, Kansai Medical University, Takii Hospital were reviewed. At the initial examination, patients had a detailed interview and underwent a comprehensive ophthalmic examinations. All patients were over 20 years of age and did not have glaucoma.Results: A total of 703 patients were evaluated. The mean (±standard error IOP of the diabetic patients was 15.5 ± 0.2 mmHg (n = 206, and was significantly higher than the 14.0 ± 0.1 mmHg (n = 497 in the nondiabetic patients (P < 0.0001. The IOP was negatively correlated with age (r = –0.202; P = 0.024 in the diabetic patients and was weakly but significantly correlated with the glycosylated hemoglobin (HbA1c level (r = 0.240; P = 0.015 in the group with diabetic retinopathy.Conclusion: The significantly higher IOP in diabetic patients and positive correlation of IOP with HbA1c levels in patients with diabetic retinopathy indicate that IOP in diabetic patients is higher, especially in those with poor control of diabetes.Keywords: diabetes mellitus, diabetic retinopathy, intraocular pressure, open-angle glaucoma

  20. Computational modeling of intraocular gas dynamics

    Science.gov (United States)

    Noohi, P.; Abdekhodaie, M. J.; Cheng, Y. L.

    2015-12-01

    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. SF6 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 SF6, the bubble expanded to 2.3 times of its initial volume during the first 23 h, but when diluted SF6 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 SF6 is 1.4 times more than that of using diluted SF6 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.

  1. The M31 pixel lensing plan campaign: MACHO lensing and self-lensing signals

    International Nuclear Information System (INIS)

    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign consists of about 1 month/year observations carried out over 4 years (2007-2010) at the 1.5 m Cassini telescope in Loiano (Astronomical Observatory of BOLOGNA, OAB) plus 10 days of data taken in 2010 at the 2 m Himalayan Chandra Telescope monitoring the central part of M31 (two fields of about 13' × 12.'6). We establish a fully automated pipeline for the search and the characterization of microlensing flux variations. As a result, we detect three microlensing candidates. We evaluate the expected signal through a full Monte Carlo simulation of the experiment completed by an analysis of the detection efficiency of our pipeline. We consider both 'self lensing' and 'MACHO lensing' lens populations, given by M31 stars and dark matter halo MACHOs, in M31 and the Milky Way, respectively. The total number of events is consistent with the expected self-lensing rate. Specifically, we evaluate an expected signal of about two self-lensing events. As for MACHO lensing, for full 0.5(10–2) M ☉ MACHO halos, our prediction is for about four (seven) events. The comparatively small number of expected MACHO versus self-lensing events, together with the small number statistics at our disposal, do not enable us to put strong constraints on that population. Rather, the hypothesis, suggested by a previous analysis, on the MACHO nature of OAB-07-N2, one of the microlensing candidates, translates into a sizeable lower limit for the halo mass fraction in form of the would-be MACHO population, f, of about 15% for 0.5 M ☉ MACHOs.

  2. The M31 pixel lensing plan campaign: MACHO lensing and self-lensing signals

    Energy Technology Data Exchange (ETDEWEB)

    Calchi Novati, S.; Scarpetta, G. [Istituto Internazionale per gli Alti Studi Scientifici (IIASS), Via Pellegrino 19, I-84019 Vietri Sul Mare (Italy); Bozza, V. [Dipartimento di Fisica E. R. Caianiello, Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (Italy); Bruni, I.; Gualandi, R. [INAF, Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Dall' Ora, M. [INAF, Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); De Paolis, F.; Ingrosso, G.; Nucita, A.; Strafella, F. [Dipartimento di Matematica e Fisica E. De Giorgi, Università del Salento, CP 193, I-73100 Lecce (Italy); Dominik, M. [SUPA, University of St Andrews, School of Physics and Astronomy, North Haugh, St Andrews, KY16 9SS (United Kingdom); Jetzer, Ph. [Institute for Theoretical Physics, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland); Mancini, L. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Safonova, M.; Subramaniam, A. [Indian Institute of Astrophysics, Bangalore 560 034 (India); Sereno, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Collaboration: PLAN Collaboration

    2014-03-10

    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign consists of about 1 month/year observations carried out over 4 years (2007-2010) at the 1.5 m Cassini telescope in Loiano (Astronomical Observatory of BOLOGNA, OAB) plus 10 days of data taken in 2010 at the 2 m Himalayan Chandra Telescope monitoring the central part of M31 (two fields of about 13' × 12.'6). We establish a fully automated pipeline for the search and the characterization of microlensing flux variations. As a result, we detect three microlensing candidates. We evaluate the expected signal through a full Monte Carlo simulation of the experiment completed by an analysis of the detection efficiency of our pipeline. We consider both 'self lensing' and 'MACHO lensing' lens populations, given by M31 stars and dark matter halo MACHOs, in M31 and the Milky Way, respectively. The total number of events is consistent with the expected self-lensing rate. Specifically, we evaluate an expected signal of about two self-lensing events. As for MACHO lensing, for full 0.5(10{sup –2}) M {sub ☉} MACHO halos, our prediction is for about four (seven) events. The comparatively small number of expected MACHO versus self-lensing events, together with the small number statistics at our disposal, do not enable us to put strong constraints on that population. Rather, the hypothesis, suggested by a previous analysis, on the MACHO nature of OAB-07-N2, one of the microlensing candidates, translates into a sizeable lower limit for the halo mass fraction in form of the would-be MACHO population, f, of about 15% for 0.5 M {sub ☉} MACHOs.

  3. Laser flare photometry: a noninvasive, objective, and quantitative method to measure intraocular inflammation.

    Science.gov (United States)

    Tugal-Tutkun, Ilknur; Herbort, Carl P

    2010-10-01

    Aqueous flare and cells are the two inflammatory parameters of anterior chamber inflammation resulting from disruption of the blood-ocular barriers. When examined with the slit lamp, measurement of intraocular inflammation remains subjective with considerable intra- and interobserver variations. Laser flare cell photometry is an objective quantitative method that enables accurate measurement of these parameters with very high reproducibility. Laser flare photometry allows detection of subclinical alterations in the blood-ocular barriers, identifying subtle pathological changes that could not have been recorded otherwise. With the use of this method, it has been possible to compare the effect of different surgical techniques, surgical adjuncts, and anti-inflammatory medications on intraocular inflammation. Clinical studies of uveitis patients have shown that flare measurements by laser flare photometry allowed precise monitoring of well-defined uveitic entities and prediction of disease relapse. Relationships of laser flare photometry values with complications of uveitis and visual loss further indicate that flare measurement by laser flare photometry should be included in the routine follow-up of patients with uveitis. PMID:19430730

  4. Individual electrostatic astigmatic tubular lenses

    International Nuclear Information System (INIS)

    Electron-optical properties of three-electrode individual astigmatic tubular lenses with similar electrode diameters are investigated. It has been assumed while calculations that gaps between the el ctrodes are infinitely small and lines separating them are presented as part of line of intersection of two cylinders with equal radius. Parameters characterizing paraxial properties of lenses and coefficients of their spherical aberration for subject position on the infinity at different ratios of electrode potential and distances between gaps are determined. The three-electrode individual lens focuses charged particle beams in one plain and it scatters them in another one in the whole chosen range of potential ratios. It is revealed that coefficients of spherical aberration in individual lenses have different signs and one of the coefficients passes through zero

  5. Patient acceptability of the Tecnis® multifocal intraocular lens

    Directory of Open Access Journals (Sweden)

    Sood P

    2011-03-01

    Full Text Available Priyanka Sood1, Maria A Woodward21Emory Eye Center, Atlanta, GA, USA; 2Kellogg Eye Center, Ann Arbor, MI, USAAbstract: Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients' desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anterior prolate IOL with a diffractive multifocal lens design. The design aims to minimize spherical aberration and improve range of focus. The purpose of this review is to assess patient acceptability of the Tecnis® multifocal intraocular lens.Keywords: Tecnis®, intraocular lens, multifocal, presbyopia 

  6. [The neuroanatomical and physiological bases of variations in intraocular pressure].

    Science.gov (United States)

    Chiquet, C; Denis, P

    2004-09-01

    Intraocular pressure displays a distinct circadian rhythm in animals and humans, with an increase at night and a decrease during the daytime. In animals, the IOP rhythm has been reported to be synchronized by environmental light and to persist in constant darkness, demonstrating a circadian component controlled by an endogenous pacemaker. The structures involved in the rhythmic regulation of intraocular pressure include the suprachiasmatic nucleus, which controls the activity of sympathetic and parasympathetic ocular innervation. These effectors are responsible for controlling the production (beta-adrenergic system) and the outflow (alpha1-adrenergic, parasympathetic system, prostaglandin) of aqueous humor. The production of aqueous humor is under adrenergic control (alpha1- and beta-receptors). Many neuropeptides such as vasoactive intestinal peptide, substance P, and the atrial natriuretic peptide are also involved in the regulation of intraocular pressure. A better understanding of the circadian regulation of intraocular pressure is needed for an appropriate treatment of ocular hypertension and glaucoma. PMID:15314570

  7. Cosmological models and gravitational lenses

    International Nuclear Information System (INIS)

    Full text: The large amount of observational data collected since the early last century by Surveys as: CLASS, SNAP, SDSS and others, made the tests possible cosmological models. What stands out most is one that uses gravitational lensing, which serves as a complement to tests with SNe-Ia. Currently, the observations indicate that the universe is accelerated expansion. Moreover to that we have the cosmic structures we observe today as the need to add more material. A proposal usual to solve these problems is to propose the existence of two dark components. This name comes from the constituents emitted any radiation. However, despite both not emit radiation they must distort space-time somehow. Thus, when a beam of light from any source in this region spreads geometrically modified, will have its trajectory changed. Therefore, the phenomenon of gravitational lensing allows infer indirectly the amount of dark matter in the universe. Moreover, the study of gravitational lensing enables to obtain cosmological parameters as the Hubble constant and density parameter. Moreover, this effect can heaven be used to detect exoplanets, or also as a natural telescope. In this study aims to assess some cosmological models using gravitational lenses and the CLASS data in tests with fluids quartessence. Such fluids are useful for treating the matter and dark energy as a single fluid. Unlike the model LambdaCDM that treats separately, i.e. in this model the universe consists of baryons, radiation, dust, dark matter and dark energy. We will use the statistics of gravitational lensing to make a comparison between the generalized Chaplygin gas and the viscous fluid. In addition, an application of statistics to the CLASS lenses will be applied in models well accepted by the scientific community. (author)

  8. Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

    OpenAIRE

    Ladan Espandar; Shameema Sikder; Majid Moshirfar

    2011-01-01

    Ladan Espandar1, Shameema Sikder2, Majid Moshirfar31Department of Ophthalmology, Tulane University, New Orleans, LA, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA; 3John A Moran Eye Center, University of Utah, Salt Lake City, UT, USAAbstract: Intraocular lens development is driven by higher patient expectations for ideal visual outcomes. The recently US Food and Drug Administration-approved Softec HD™ lens is an aspheric, hydrophilic acrylic intraocular le...

  9. Patient acceptability of the Tecnis® multifocal intraocular lens

    OpenAIRE

    Woodward, Maria

    2011-01-01

    Priyanka Sood1, Maria A Woodward21Emory Eye Center, Atlanta, GA, USA; 2Kellogg Eye Center, Ann Arbor, MI, USAAbstract: Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients' desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL) designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anter...

  10. Patient acceptability of the Tecnis® multifocal intraocular lens

    OpenAIRE

    Sood, Priyanka; Woodward, Maria A.

    2011-01-01

    Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients’ desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL) designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anterior prolate IOL with a diffractive multifocal lens design. The design aims to minimize spherical aberration and improve range of focus....

  11. Intraocular Gnathostomiasis: Report of a Case and Review of Literature

    OpenAIRE

    Pillai, Gopal S.; Kumar, Anil; Radhakrishnan, Natasha; Maniyelil, Jayasree; Shafi, Tufela; Dinesh, Kavitha R.; Karim, Shamsul

    2012-01-01

    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...

  12. Metabolic Syndrome as a Risk Factor for Elevated Intraocular Pressure

    OpenAIRE

    Sahinoglu-Keskek, Nedime; Keskek, Sakir Ozgur; Cevher, Selim; Kirim, Sinan; Kayiklik, Asim; Ortoglu, Gulay; Saler, Tayyibe

    2014-01-01

    Objective: The aim of this study was to investigate the association between intraocular pressure and metabolic syndrome by comparing central corneal thicknesses. Methods: One hundred sixty-two subjects were enrolled in this cross-sectional study, with 89 subjects in a metabolic syndrome group and 73 subjects in a control group. Ophthalmological examinations, including intraocular pressure and central corneal thickness measurements, were performed on each subject. Serum fasting glucose, trigly...

  13. Design of spherical symmetric gradient index lenses

    OpenAIRE

    Miñano Dominguez, Juan Carlos; Grabovičkić, Dejan; Benitez Gimenez, Pablo; Gonzalez Lopez, Juan Carlos; Santamaria Galdon, Maria Asuncion

    2012-01-01

    Spherical symmetric refractive index distributions also known as Gradient Index lenses such as the Maxwell-Fish-Eye (MFE), the Luneburg or the Eaton lenses have always played an important role in Optics. The recent development of the technique called Transformation Optics has renewed the interest in these gradient index lenses. For instance, Perfect Imaging within the Wave Optics framework has recently been proved using the MFE distribution. We review here the design problem of these lenses, ...

  14. Relation between intraocular pressure and size of transverse sinuses

    International Nuclear Information System (INIS)

    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.)

  15. 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.)

  16. Magnetic Nanoparticles as Intraocular Drug Delivery System to Target Retinal Pigmented Epithelium (RPE)

    Science.gov (United States)

    Giannaccini, Martina; Giannini, Marianna; Calatayud, M. Pilar; Goya, Gerardo F.; Cuschieri, Alfred; Dente, Luciana; Raffa, Vittoria

    2014-01-01

    One of the most challenging efforts in drug delivery is the targeting of the eye. The eye structure and barriers render this organ poorly permeable to drugs. Quite recently the entrance of nanoscience in ocular drug delivery has improved the penetration and half-life of drugs, especially in the anterior eye chamber, while targeting the posterior chamber is still an open issue. The retina and the retinal pigment epithelium/choroid tissues, located in the posterior eye chamber, are responsible for the majority of blindness both in childhood and adulthood. In the present study, we used magnetic nanoparticles (MNPs) as a nanotool for ocular drug delivery that is capable of specific localization in the retinal pigmented epithelium (RPE) layer. We demonstrate that, following intraocular injection in Xenopus embryos, MNPs localize specifically in RPE where they are retained for several days. The specificity of the localization did not depend on particle size and surface properties of the MNPs used in this work. Moreover, through similar experiments in zebrafish, we demonstrated that the targeting of RPE by the nanoparticles is not specific for the Xenopus species. PMID:24451140

  17. Magnetic Nanoparticles as Intraocular Drug Delivery System to Target Retinal Pigmented Epithelium (RPE

    Directory of Open Access Journals (Sweden)

    Martina Giannaccini

    2014-01-01

    Full Text Available One of the most challenging efforts in drug delivery is the targeting of the eye. The eye structure and barriers render this organ poorly permeable to drugs. Quite recently the entrance of nanoscience in ocular drug delivery has improved the penetration and half-life of drugs, especially in the anterior eye chamber, while targeting the posterior chamber is still an open issue. The retina and the retinal pigment epithelium/choroid tissues, located in the posterior eye chamber, are responsible for the majority of blindness both in childhood and adulthood. In the present study, we used magnetic nanoparticles (MNPs as a nanotool for ocular drug delivery that is capable of specific localization in the retinal pigmented epithelium (RPE layer. We demonstrate that, following intraocular injection in Xenopus embryos, MNPs localize specifically in RPE where they are retained for several days. The specificity of the localization did not depend on particle size and surface properties of the MNPs used in this work. Moreover, through similar experiments in zebrafish, we demonstrated that the targeting of RPE by the nanoparticles is not specific for the Xenopus species.

  18. N-body lensed CMB maps: lensing extraction and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Antolini, Claudia; Martinelli, Matteo; Baccigalupi, Carlo [SISSA, Via Bonomea 265, Trieste, I-34136 (Italy); Fantaye, Yabebal [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, Oslo, N-0315 (Norway); Carbone, Carmelita, E-mail: claudia.antolini@sissa.it, E-mail: y.t.fantaye@astro.uio.no, E-mail: mmartin@sissa.it, E-mail: carmelita.carbone@brera.inaf.it, E-mail: bacci@sissa.it [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46, Merate, I-23807 (Italy)

    2014-02-01

    We reconstruct shear maps and angular power spectra from simulated weakly lensed total intensity (TT) and polarised (EB) maps of the Cosmic Microwave Background (CMB) anisotropies, obtained using Born approximated ray-tracing through the N-body simulated Cold Dark Matter (CDM) structures in the Millennium Simulations (MS). We compare the recovered signal with the ΛCDM prediction, on the whole interval of angular scales which is allowed by the finite box size, extending from the degree scale to the arcminute, by applying a quadratic estimator in the flat sky limit; we consider PRISM-like instrumental specification for future generation CMB satellites, corresponding to arcminute angular resolution of 3.2' and sensitivity of 2.43 μK-arcmin. The noise contribution in the simulations closely follows the estimator prediction, becoming dominated by limits in the angular resolution for the EB signal, at ℓ ≅ 1500. The recovered signal shows no visible departure from predictions of the weak lensing power within uncertainties, when considering TT and EB data singularly. In particular, the reconstruction precision reaches the level of a few percent in bins with Δℓ ≅ 100 in the angular multiple interval 1000∼<ℓ∼<2000 for T, and about 10% for EB. Within the adopted specifications, polarisation data do represent a significant contribution to the lensing shear, which appear to faithfully trace the underlying N-body structure down to the smallest angular scales achievable with the present setup, validating at the same time the latter with respect to semi-analytical predictions from ΛCDM cosmology at the level of CMB lensing statistics. This work demonstrates the feasibility of CMB lensing studies based on large scale simulations of cosmological structure formation in the context of the current and future high resolution and sensitivity CMB experiment.

  19. Intracapsular dexamethasone implant in patients undergoing phacoemulsification and intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Lucas Monferrari Monteiro Vianna

    2013-08-01

    Full Text Available PURPOSE: To relate the outcomes of 7 eyes of 7 patients in which a dexamethasone 0.7 mg implant (Ozurdex® was placed inside the capsule bag after phacoemulsification and intraocular lens (IOL implantation and compare with the fellow eyes, that were operated by the same technique and received dexamethasone eyedrops in the post-operatory. METHODS: Report review of 7 eyes of 7 patients who received dexamethasone 0.7 mg implant after phacoemulsification and IOL, comparing them to the fellow eyes. All the patients underwent bilateral cataract surgery, with one month interval, by the same technique and by experienced surgeons, without complications. Post operatory medication consisted of moxifloxacin eye drops for all the 14 eyes and topic dexamethasone for the 7 eyes that did not received the implant. RESULTS: Nuclear cataract classification (according to LOCS III was 3.28 ± 0.69 in the implant eye group and 3.14 ± 0.83 in the fellow eye group. Postoperative best spectacle correct visual acuity (BSCVA was 0.85 ± 0.12 and 0.87 ± 0.13, respectively in the implant and fellow eye groups. The intraocular pressure remained stable and similar to the pre-operative measurements. Anterior chamber reaction and cornea edema were similar in both groups in the follow-up. Two of the four no sutured pellet migrated to the anterior chamber during the first post-operative week and had to be repositioned. Another no sutured pellet dislocated and remained partially inside the capsule bag. The 3 patients with IOL haptic-sutured pellet had no complications. CONCLUSIONS: In the present study, dexamethasone 0.7mg implant were effective in controlling the inflammation after phacoemulsification and IOL implantation, with no significant side effects.

  20. In Vivo Imaging of Intraocular Fluidics in Vitrectomized Swine Eyes Using a Digital Fluoroscopy System

    Science.gov (United States)

    Tandogan, Tamer; Khoramnia, Ramin; Auffarth, Gerd Uwe; Koss, Michael Janusz; Choi, Chul Young

    2016-01-01

    Purpose. To describe the characteristics of intraocular fluidics during cataract surgery in swine eyes with prior vitrectomy. Methods. We prepared three groups of enucleated swine eyes (nonvitrectomized, core, and totally vitrectomized). Irrigation and aspiration were performed (2.7 mm conventional sleeved phacosystem) using a balanced saline solution mixed with a water-soluble radiopaque contrast medium at 1 : 1 ratio. We imaged the eyes using a digital fluoroscopy system (DFS) during phacoemulsification and compared the characteristics of the intraocular fluid dynamics between the groups. Results. The anterior chamber depth (ACD) after the commencement of irrigation differed between groups (2.25 ± 0.06 mm; 2.33 ± 0.06 mm; 3.17 ± 0.11 mm), as well as the height of the fluid flowing from the anterior chamber into the posterior cavity that was identified by lifting up the iris to correct the infusion deviation syndrome (0.00 ± 0.00 mm; 0.41 ± 0.04 mm; 2.19 ± 0.35 mm). Conclusions. DFS demonstrated differences in fluid dynamics during phacoemulsification in swine eyes with or without prior vitrectomy. In completely vitrectomized eyes, the large ACD, which developed during phacoemulsification, could be reduced by lifting the iris and allowing the fluid to shift to the posterior cavity. Recognizing the differences in fluidics of vitrectomized eyes as compared to those of the nonvitrectomized eyes may reduce the frequency of intraoperative complications. PMID:27127645

  1. Visual Performance after Bilateral Implantation of a Four-Haptic Diffractive Toric Multifocal Intraocular Lens in High Myopes.

    Science.gov (United States)

    Chang, John S M; Chan, Vincent K C; Ng, Jack C M; Law, Antony K P

    2016-01-01

    Background. The vision with diffractive toric multifocal intraocular lenses after cataract surgery in long eyes has not been studied previously. Objectives. To report visual performance after bilateral implantation of a diffractive toric multifocal intraocular lens in high myopes. Methods. Prospective, observational case series to include patients with axial length of ≥26 mm and corneal astigmatism of >1 dioptre who underwent bilateral AT LISA 909M implantation. Postoperative examinations included photopic and mesopic distance, intermediate, and near visual acuity; photopic contrast sensitivity; visual symptoms (0-5); satisfaction (1-5); and spectacle independence rate. Results. Twenty-eight eyes (14 patients) were included. Postoperatively, mean photopic monocular uncorrected distance, intermediate, and near visual acuities (logMAR) were 0.12 ± 0.20 (standard deviation), 0.24 ± 0.16, and 0.29 ± 0.21, respectively. Corresponding binocular values were -0.01 ± 0.14, 0.13 ± 0.12, and 0.20 ± 0.19, respectively. One eye (4%) had one-line loss in vision. Under mesopic condition, intermediate vision and near vision decreased significantly (all P ≤ 0.001). Contrast sensitivity at all spatial frequencies did not improve significantly under binocular condition (all P > 0.05). Median scores for halos, night glare, starbursts, and satisfaction were 0.50, 0.00, 0.00, and 4.25, respectively. Ten patients (71%) reported complete spectacle independence. Conclusions. Bilateral implantation of the intraocular lens in high myopes appeared to be safe and achieved good visual performance and high satisfaction. PMID:27563460

  2. Gravitational lensing by gravitational waves

    OpenAIRE

    Bisnovatyi-Kogan, G. S.; Tsupko, O. Yu.

    2008-01-01

    Gravitational lensing by gravitational wave is considered. We notice that although final and initial direction of photons coincide, displacement between final and initial trajectories occurs. This displacement is calculated analytically for the plane gravitational wave pulse. Estimations for observations are discussed.

  3. 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…

  4. Gravitational Lensing of Supernova Neutrinos

    OpenAIRE

    Mena Requejo, Olga; Mocioiu, Irina; Quigg, Chris

    2006-01-01

    The black hole at the center of the galaxy is a powerful lens for supernova neutrinos. In the very special circumstance of a supernova near the extended line of sight from Earth to the galactic center, lensing could dramatically enhance the neutrino flux at Earth and stretch the neutrino pulse.

  5. Peroperative microbial contamination of anterior chamber aspirates during extracapsular cataract extraction and phacoemulsification

    OpenAIRE

    Beigi, B; WESTLAKE, W.; Mangelschots, E.; Chang, B.; Rich, W; Riordan, T

    1997-01-01

    BACKGROUND—The normal conjunctival flora is one of the main sources of intraocular contamination during cataract surgery. The theory that the positive anterior chamber (AC) pressure during phacoemulsification (phaco), and the smaller wound utilised, might reduce the rate of contamination was studied.
METHODS—The peroperative AC aspirates of 210 consecutive patients undergoing cataract surgery were assessed. In group 1, 100 patients underwent a standard extracapsular cataract extraction (ECCE)...

  6. Associated depression in pseudophakic patients with intraocular lens with and without chromophore

    Science.gov (United States)

    Mendoza-Mendieta, María Elena; Lorenzo-Mejía, Ana Aurora

    2016-01-01

    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 phacoemul-sification 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 observed in the elderly population, whereas no patients in the group with transparent IOLs had depression. PMID:27099465

  7. A study of brachytherapy for intraocular tumor

    International Nuclear Information System (INIS)

    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)

  8. Streamer chamber: pion decay

    CERN Multimedia

    1992-01-01

    The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

  9. Prototype multiwire proportional chamber

    CERN Multimedia

    1975-01-01

    Chambers of this type were initially developed within the Alpha project (finally not approved). They were designed such to minimize the radiation length with a view to a mass spectrometer of high resolution meant to replace the Omega detector. The chambers were clearly forerunners for the (drift) chambers later built for R606 with the novel technique of crimping the wires. See also photo 7510039X.

  10. Electromagnetic reverberation chambers

    CERN Document Server

    Besnier, Philippe

    2013-01-01

    Dedicated to a complete presentation on all aspects of reverberation chambers, this book provides the physical principles behind these test systems in a very progressive manner. The detailed panorama of parameters governing the operation of electromagnetic reverberation chambers details various applications such as radiated immunity, emissivity, and shielding efficiency experiments.In addition, the reader is provided with the elements of electromagnetic theory and statistics required to take full advantage of the basic operational rules of reverberation chambers, including calibration proc

  11. Spontaneous dislocation of a transparent lens to the anterior chamber: A case report

    OpenAIRE

    Jovanović Miloš; Stefanović Ivan

    2010-01-01

    Introduction. The causes leading to dislocation of the natural lenses are different involving injuries, hereditary diseases and spontaneous dislocation. Spontaneous dislocation of a transparent natural lens is extremely rare, especially dislocation of the anterior eye chamber. We report a case of spontaneous dislocation of the transparent natural lens to the anterior eye chamber in a patient who had no history of eye injuries. Case Outline. The patient was a 17-year old boy. Lens dislocation ...

  12. Intraocular Lens Power Calculation after Corneal Refractive Surgery

    Directory of Open Access Journals (Sweden)

    Mohammad-Ali Javadi

    2012-01-01

    Full Text Available Purpose: To report refractive outcomes following phacoemulsification (PE and posterior chamber intraocular lens (PCIOL implantation in eyes with previous corneal refractive surgery. Methods: In this retrospective comparative study, 18 consecutive eyes of 14 patients with previous keratorefractive surgery for myopia including photorefractive keratectomy (PRK, 6 eyes; 33.3% and laser in situ keratomileusis (LASIK, 12 eyes; 66.7% underwent PE+PCIOL. Computerized corneal topography was employed to determine the flattest keratometric reading within the 3-mm central zone. This value was inserted into the Sanders-Retzlaff-Kraff/T (SRK/T formula to calculate IOL power. IOL power selected for implantation was 1 D greater than the calculated value described above. Results: Mean age and follow-up period were 54.1±11.5 years and 29.9±26.3 months, respectively. Mean implanted lens power was 18.56±3.86 D which was not significantly different from mean back-calculated IOL power for target refraction (19.04±4.16 D (P=0.28. There was no significant difference between mean target refraction (-0.94±0.52 D and achieved postoperative spherical equivalent refractive error (-0.62±1.06 at final follow-up (P=0.28. The achieved spherical equivalent refractive error was within ±0.50 D of intended refraction in 8 (44.4% eyes, within ±1.0 D in 11 (61.1% eyes, and within ±2.0 D in 16 (88.9% eyes. In a subgroup of patients (5 eyes with complete pre-refractive surgery data, the difference between post-refractive surgery keratometry method and all other methods (P=0.02 and between the current method and the Feiz-Mannis method (P=0.01 was statistically significant. Conclusion: The method suggested herein is simple and independent of pre-refractive surgery data with results comparable to other commonly used methods.

  13. Comparison of two optical biometers in intraocular lens power calculation

    Directory of Open Access Journals (Sweden)

    Sheng Hui

    2014-01-01

    Full Text Available Aims: To compare the consistency and accuracy in ocular biometric measurements and intraocular lens (IOL power calculations using the new optical low-coherence reflectometry and partial coherence interferometry. Subjects and Methods: The clinical data of 122 eyes of 72 cataract patients were analyzed retrospectively. All patients were measured with a new optical low-coherence reflectometry system, using the LENSTAR LS 900 (Haag Streit AG/ALLEGRO BioGraph biometer (Wavelight., AG, and partial coherence interferometry (IOLMaster V.5.4 [Carl Zeiss., Meditec, AG] before phacoemulsification and IOL implantation. Repeated measurements, as recommended by the manufacturers, were performed by the same examiner with both devices. Using the parameters of axial length (AL, corneal refractive power (K1 and K2, and anterior chamber depth (ACD, power calculations for AcrySof SA60AT IOL were compared between the two devices using five formulas. The target was emmetropia. Statistical analysis was performed using Statistical Package for the Social Sciences software (SPSS 13.0 with t-test as well as linear regression. A P value < 0.05 was considered to be statistically significant. Results: The mean age of 72 cataract patients was 64.6 years ± 13.4 [standard deviation]. Of the biometry parameters, K1, K2 and [K1 + K2]/2 values were significantly different between the two devices (mean difference, K1: −0.05 ± 0.21 D; K2: −0.12 ± 0.20 D; [K1 + K2]/2: −0.08 ± 0.14 D. P <0.05. There was no statistically significant difference in AL and ACD between the two devices. The correlations of AL, K1, K2, and ACD between the two devices were high. The mean differences in IOL power calculations using the five formulas were not statistically significant between the two devices. Conclusions: New optical low-coherence reflectometry provides measurements that correlate well to those of partial coherence interferometry, thus it is a precise device that can be used for the

  14. [Intraocular Pressure Sensor Based on a Contact Lens].

    Science.gov (United States)

    Guo, Xuhong; Pet, Weihua; Yao, Zhaolin; Chen, Yuanfang; Hu, Xiaohui; Chen, Hongda; Zhu, Jingyuan; Wu, Huijuan

    2016-02-01

    Intraocular pressure detection has a great significance for understanding the status of eye health, prevention and treatment of diseases such as glaucoma. Traditional intraocular pressure detection needs to be held in the hospital. It is not only time-consuming to doctors and patients, but also difficult to achieve 24 hour-continuous detection. Microminiaturization of the intraocular pressure sensor and wearing it as a contact lens, which is convenient, comfortable and noninvasive, can solve this problem because the soft contact lens with an embedded micro fabricated strain gauge allows the measurement of changes in corneal curvature to correlate to variations of intraocular pressure. We fabricated a strain gauge using micro-electron mechanical systems, and integrated with the contact lens made of polydimethylsiloxane (PDMS) using injection molding. The experimental results showed that the sensitivity was 100. 7 µV/µm. When attached to the corneal surface, the average sensitivity of sensor response of intraocular pressure can be 125.8 µV/mm Hg under the ideal condition. PMID:27382734

  15. Effects of 2-alkynyladenosine derivatives on intraocular pressure in rabbits.

    Science.gov (United States)

    Konno, Takashi; Ohnuma, Shin-ya; Uemoto, Kazuhiro; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Endo, Kazuki; Hosokawa, Tomokazu; Nakahata, Norimichi

    2004-02-23

    We evaluated the activities of 2-alkynyladenosine derivatives, relatively selective adenosine A2 receptor agonists, in the intraocular pressure regulation in rabbits. An adenosine A2 receptor agonist 2-[p-(2-carboxyethyl)phenylethylamino]-5'-N-ethylcarboxamidoadenosine (CGS-21680) decreased intraocular pressure, while another A2 receptor agonist 2-(phenylamino)adenosine transiently increased it. The first group of 2-alkynyladenosine derivatives (1-hexyn-1-yl derivatives) caused a transient increase followed by decrease in intraocular pressure, while the second group (1-octyn-1-yl and 6-cyano-1-hexyn-1-yl derivatives) only decreased it. The second group is also effective in the ocular hypertensive models induced by water-loading and alpha-chymotrypsin. The outflow facility was increased by a 1-octyn-1-yl derivative. Both increase and decrease in intraocular pressure induced by 2-alkynyladenosine derivatives were inhibited by an adenosine A2 receptor antagonist 3,7-dimethyl-1-propargylxanthine, but not by an adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropyl xanthine. These findings suggest that 2-alkynyladenosine derivatives may affect intraocular pressure via adenosine A2 receptor, and 2-alkynyladenosine derivative-induced ocular hypotension is due to the increase of outflow facility. PMID:14985053

  16. 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

  17. [Techniques for preparing postmortem human eyes to perform anterior segment intraocular surgery].

    Science.gov (United States)

    Vargas, L G; Werner, L; Pandey, S K; Werner, L P; Schmidbauer, J M; Zuleta, V; Escobar-Gómez, M; Apple, D J

    2003-02-01

    We describe different methods to prepare postmortem human or animal eyes used at the Center for Research in Ocular Therapeutics and Biodevices at the Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA. These techniques have been utilized for performing different surgical procedures (phacoemulsification, extracapsular cataract extraction, etc.), and for training of surgeons in-transition. Performing these techniques in the wet-laboratory contributed to improve surgical skills to perform the critical steps of the phacoemulsification surgery. Pathological evaluation of pseudophakic postmortem human eyes using the Miyake-Apple posterior view and histology was helpful to analyze postoperative complications of cataract surgery (anterior capsule opacification and posterior capsule opacification) secondary to postoperative proliferation of lens epithelial cells into the capsular bag. Modifications in the surgical techniques and/or lens design may be helpful to reduce these postoperative complications. Implantation of various aphakic and phakic intraocular lenses in postmortem human eyes as well as animal eyes was helpful to analyze the sizing and fitting of new lens designs within the eye. PMID:12647248

  18. Visual outcomes and optical quality after implantation of a diffractive multifocal toric intraocular lens

    Science.gov (United States)

    Chen, Xiangfei; Zhao, Ming; Shi, Yuhua; Yang, Liping; Lu, Yan; Huang, Zhenping

    2016-01-01

    Background: This study evaluated the visual function after implantation of a multifocal toric intraocular lenses (IOLs). Materials and Methods: This study involved 10 eyes from eight cataract patients with corneal astigmatism of 1.0 diopter (D) or higher who had received phacoemulsification with implantation of an AcrySof IQ ReSTOR Toric IOL. Six-month evaluations included visual acuity, spherical equivalent (SE), defocus curve, residual astigmatism, IOL rotation, contrast sensitivity (CS), wavefront aberrations, modulation transfer function (MTF), and patient satisfaction assessments. Results: At 6 months postoperatively, uncorrected distance visual acuity (logarithm of the minimum angle of resolution) was 0.09 ± 0.04, corrected distance visual acuity was 0.02 ± 0.11, and uncorrected near visual acuity was 0.12 ± 0.07. The mean SE was −0.095 ± 0.394 D (±0.50 D in 90%). Refractive astigmatism at the 6-month follow-up visit was significantly reduced to 0.35 ± 0.32 D from 1.50 ± 0.41 D presurgery (P 0.05). There was an increase in MTF results between preoperative and postoperative evaluations at all spatial frequencies. Conclusions: The diffractive multifocal toric IOL is able to provide a predictable astigmatic correction with apparently outstanding levels of optical quality after implantation. PMID:27221680

  19. The impact of multifocal intraocular lens in retinal imaging with optical coherence tomography.

    Science.gov (United States)

    Dias-Santos, Arnaldo; Costa, Lívio; Lemos, Vanessa; Anjos, Rita; Vicente, André; Ferreira, Joana; Cunha, João Paulo

    2015-02-01

    Multifocal intraocular lenses (MF IOLs) have concentric optical zones with different dioptric power, enabling patients to have good visual acuity at multiple focal points. However, several optical limitations have been attributed to this particular design. The purpose of this study is to access the effect of MF IOLs design on the accuracy of retinal optical coherence tomography (OCT). Cross-sectional study conducted at the Refractive Surgery Department of Central Lisbon Hospital Center. Twenty-three eyes of 15 patients with a diffractive MF IOL and 27 eyes of 15 patients with an aspheric monofocal IOL were included in this study. All patients underwent OCT macular scans using Heidelberg Spectralis(®). Macular thickness and volume values and image quality (Q factor) were compared between the two groups. There were no statistically significant differences between both groups regarding macular thickness or volume measurements. Retinal OCT image quality was significantly lower in the MF IOL group (p image quality. However, this fact does not seem to compromise the accuracy of spectral domain OCT retinal measurements. PMID:25381578

  20. Managing bevacizumab-induced intraocular inflammation

    OpenAIRE

    Subijay Sinha; Nagender Vashisht; Pradeep Venkatesh; Sat Pal Garg

    2012-01-01

    The outcome of four cases of sterile endophthalmitis that developed after intravitreal injections of bevacizumab has been reported here. All four eyes received 1.25 mg/0.05 ml intravitreal bevacizumab from 0.2-ml aliquots for different etiologies. The inflammation predominantly involved the anterior chamber with mild vitreous reaction. All patients were culture negative and regained preinjection visual acuity and were culture negative following intravitreal antibiotic administration. This rep...

  1. Gravitational Lensing - Einstein's Unfinished Symphony

    CERN Document Server

    Treu, Tommaso

    2014-01-01

    Gravitational lensing - the deflection of light rays by gravitating matter - has become a major tool in the armoury of the modern cosmologist. Proposed nearly a hundred years ago as a key feature of Einstein's theory of General Relativity, we trace the historical development since its verification at a solar eclipse in 1919. Einstein was apparently cautious about its practical utility and the subject lay dormant observationally for nearly 60 years. Nonetheless there has been rapid progress over the past twenty years. The technique allows astronomers to chart the distribution of dark matter on large and small scales thereby testing predictions of the standard cosmological model which assumes dark matter comprises a massive weakly-interacting particle. By measuring distances and tracing the growth of dark matter structure over cosmic time, gravitational lensing also holds great promise in determining whether the dark energy, postulated to explain the accelerated cosmic expansion, is a vacuum energy density or a...

  2. Extinction Curves of Lensing Galaxies

    Science.gov (United States)

    Elíasdóttir, Árdís

    2006-09-01

    Dust extinction causes light from distant sources to be dimmed on itsway to the observer. In cosmological studies, such as SN Ia studies,it is of great importance that the effects of dust extinction becorrectly accounted for. However, although dust properties, andhence extinction, are expected to vary with redshift, not very muchis known about the extinction properties of high redshift galaxies.This is because the methods traditionally used to study extinctioncurves are only applicable for the most nearby galaxies. Studyinggravitationally lensed quasars is an emerging method of studying thedust extinction of high redshift galaxies. I will present an ESO VLTstudy of 10 such lensing galaxies, with redshifts up to 1. The 10systems display varying amount and type of extinction, with thedoubly imaged quasar B1152+199 showing the greatest extinction with A(V)=2.4 and R_V=2.1 for a Galactic type extinction law.

  3. 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.

  4. The relation between intraocular pressure change and plasma natriuretic peptide under simulated hypobaric conditions

    Directory of Open Access Journals (Sweden)

    Karadag Remzi

    2010-01-01

    Full Text Available Purpose: To ascertain whether the changes in intraocular pressure (IOP that occur during hypobaric hypoxic exposure are related to plasma N-terminal pro-brain natriuretic peptide (BNP levels. Materials and Methods: The study group comprised 26 healthy participants (all male, mean age 23.1 years. IOP was measured at local ground level, (792 m above sea level, then while in a chamber providing hypobaric hypoxic conditions (the subjects were exposed to a pressure equivalent to 9144 m for 1-3 min, and again after exit from the chamber. In each condition, the mean of three consecutive measurements of IOP was calculated for each eye. For BNP measurements, blood samples were drawn before the participants entered the chamber and just after they left the chamber. Results: IOP during hypobaric hypoxic exposure (18.00 ± 3.70 mmHg was significantly greater than that before (15.66 ± 2.10 mmHg, P < 0.001 or after (16.10 ± 2.63 mmHg, P = 0.001 the exposure. IOP levels before and after the exposure were not significantly different (P = 0.136. Plasma BNP levels measured before and after exposure to hypobaric hypoxic conditions were not significantly different (P = 0.462. Conclusion: Plasma BNP levels did not change after short-term hypobaric hypoxic exposure, while the IOP increased. This increase may have been caused by some other systemic factors. As the hypobaric hypoxic conditions were reversed, IOP decreased to normal levels.

  5. High resolution drift chambers

    International Nuclear Information System (INIS)

    High precision drift chambers capable of achieving less than or equal to 50 μm resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs

  6. Gravitational Lensing: Einstein's unfinished symphony

    Science.gov (United States)

    Treu, Tommaso; Ellis, Richard S.

    2015-01-01

    Gravitational lensing - the deflection of light rays by gravitating matter - has become a major tool in the armoury of the modern cosmologist. Proposed nearly a hundred years ago as a key feature of Einstein's theory of general relativity, we trace the historical development since its verification at a solar eclipse in 1919. Einstein was apparently cautious about its practical utility and the subject lay dormant observationally for nearly 60 years. Nonetheless there has been rapid progress over the past twenty years. The technique allows astronomers to chart the distribution of dark matter on large and small scales thereby testing predictions of the standard cosmological model which assumes dark matter comprises a massive weakly-interacting particle. By measuring the distances and tracing the growth of dark matter structure over cosmic time, gravitational lensing also holds great promise in determining whether the dark energy, postulated to explain the accelerated cosmic expansion, is a vacuum energy density or a failure of general relativity on large scales. We illustrate the wide range of applications which harness the power of gravitational lensing, from searches for the earliest galaxies magnified by massive clusters to those for extrasolar planets which temporarily brighten a background star. We summarise the future prospects with dedicated ground and space-based facilities designed to exploit this remarkable physical phenomenon.

  7. Uncontrolled Selling of Contact Lenses

    Directory of Open Access Journals (Sweden)

    Cem Sundu

    2015-05-01

    Full Text Available Objectives: To evaluate the opticians’ perspective about selling and applying contact lenses (CL in the provincial centre of Mersin. Materials and Methods: Twenty opticians who work in the 4 main districts in the provincial centre of Mersin were included in the study. A questionnaire form which was prepared before was filled out by the participants. Results: Seventy-eight percent of the opticians were selling CL without prescription, whereas 25% also carried out its fitting. Seventyfive percent of the participants did not get any education about contact lenses, while 65% of them were feeling themselves disqualified about CLs. Furthermore, half of the participants did not have enough knowledge about the complications associated with CL usage and 75% of them wanted to receive information about CLs. Conclusion: As a result of the questionnaire, we found out that a significant part of the participants were both selling and fitting contact lenses without prescription. We believe that auditing the opticians is as important as educating the contact lens users. (Turk J Ophthalmol 2015; 45: 102-104

  8. Gravitational lensing in plasmic medium

    International Nuclear Information System (INIS)

    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

  9. Evaluation of the motion of surgical instruments during intraocular surgery

    Science.gov (United States)

    Hubschman, J-P; Son, J; Allen, B; Schwartz, S D; Bourges, J-L

    2011-01-01

    Purpose Robot assistance in ocular microsurgery could improve precision, dexterity, save time or prevent complications by task automation, and provide access to ocular surgery in undeserved countries by teleoperation. However, to design robotic devices, the range of motion of surgical instruments needs to be precisely quantified. Methods An electromagnetic tracking system was developed for intraocular surgery in order to quantify the movements of ophthalmic surgeons. Kinematics of surgical steps during phacoemulsification and pars plana vitrectomy procedures were determined by measuring the maximum translation and angular range of motion of intraocular surgical tools in the three planes. Conclusion Important variations in amplitudes of rotation and translation were measured between both hands and between surgical tasks. These parameters may be used to develop a robotic intraocular surgical system or to improve training. PMID:21527954

  10. 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...

  11. Characterization of sand lenses embedded in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K.E.S.; Nilsson, B.; Bjerg, Poul Løgstrup

    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...... parameters is defined to allow characterization of sand lenses. The proposed classification scheme uses a stringent terminology to distinguish several types of sand lenses based on the geometry. It includes sand layers, sand sheets, sand bodies, sand pockets and sand stringers. The methodology has been...... lenses in various glacial environments. Due to the complex and mutable appearance of sand lenses, geometric descriptions can reveal the deformation history and even give indications on the palaeo-glaciological conditions during the deposition of the surrounding tills. This information can support the...

  12. Corrigendum: Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

    Directory of Open Access Journals (Sweden)

    Espandar L

    2011-02-01

    Full Text Available Espandar L, Sikder S, Moshirfar M. Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision. Clin Ophthalmol. 2011;5:65–70.There was an error in the reported optic size of Lenstec’s Softec HD intraocular lens, which was reported to be 5.5 mm in Espandar et al’s work, but is 5.75 mm.Please see the specifications on Lenstec’s Web site for further details (see http://www.lenstec.com/lenstec/hd_specs.html.Read the original article

  13. Immediate intraocular pressure response to selective laser trabeculoplasty

    OpenAIRE

    Lanzetta, P; Menchini, U; Virgili, G

    1999-01-01

    BACKGROUND/AIMS—Selective laser trabeculoplasty targets the pigmented trabecular meshwork cells without damage to the trabecular meshwork architecture in vitro. A study was conducted in vivo of eight eyes with uncontrolled open angle glaucoma to ascertain the immediate intraocular response to selective laser trabeculoplasty.
METHODS—The trabecular meshwork of each eye was treated 360° with a frequency doubled Q-switched Nd:YAG laser. Intraocular pressure was measured 1, 2, 24 hours and 1, 4, ...

  14. 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 ...

  15. M31 Pixel Lensing PLAN Campaign: MACHO Lensing and Self Lensing Signals

    CERN Document Server

    Novati, S Calchi; Bruni, I; Dall'Ora, M; De Paolis, F; Dominik, M; Gualandi, R; Ingrosso, G; Jetzer, Ph; Mancini, L; Nucita, A; Safonova, M; Scarpetta, G; Sereno, M; Strafella, F; Subramaniam, A; Gould, A

    2014-01-01

    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign consists of about 1 month/year observations carried out during 4 years (2007-2010) at the 1.5m Cassini telescope in Loiano ("Astronomical Observatory of BOLOGNA", OAB) plus 10 days of data taken in 2010 at the 2m Himalayan Chandra Telescope (HCT) monitoring the central part of M31 (two fields of about 13'x12.6'). We establish a fully automated pipeline for the search and the characterization of microlensing flux variations: as a result we detect 3 microlensing candidates. We evaluate the expected signal through a full Monte Carlo simulation of the experiment completed by an analysis of the detection efficiency of our pipeline. We consider both "self lensing" and "MACHO lensing" lens populations, given by M31 stars and dark matter halo MACHOs, in the M31 and the Milky Way (MW), respectively. The...

  16. cluster-lensing: Tools for calculating properties and weak lensing profiles of galaxy clusters

    Science.gov (United States)

    Ford, Jes

    2016-05-01

    The cluster-lensing package calculates properties and weak lensing profiles of galaxy clusters. Implemented in Python, it includes cluster mass-richness and mass-concentration scaling relations, and NFW halo profiles for weak lensing shear, the differential surface mass density ΔΣ(r), and for magnification, Σ(r). Optionally the calculation will include the effects of cluster miscentering offsets.

  17. Facoemulsificação, vitrectomia via pars plana e implante de lente intra-ocular em olhos com retinopatia diabética proliferativa Phacoemulsification, pars plana vitrectomy and intraocular lens implant in eyes with proliferative diabetic retinopathy

    Directory of Open Access Journals (Sweden)

    Armando Belfort Mattos

    2004-06-01

    realizar a vitrectomia via pars plana, ao invés de se realizar uma segunda cirurgia, que seria somente para a remoção da catarata após a vitrectomia pars plana, é técnica segura e capaz de promover a melhora da acuidade visual além de ser menos agressiva para o paciente. O potencial para melhora da acuidade visual final é limitado pela gravidade da retinopatia diabética.PURPOSE: To evaluate the outcomes and the best technique for a combined phacoemulsification (PHACO, pars plana vitrectomy (PPV and posterior chamber intraocular lens insertion (PCIOL in one single procedure for patients with proliferative diabetic retinopathy. METHODS: We reviewed charts of 47 (53 eyes patients with proliferative diabetic retinopathy who underwent combined phacoemulsification with posterior chamber intraocular lens implant and pars plana vitrectomy performed between January 1991 and September 1998 at the Bascom Palmer Eye Institute, eye hospital affiliated with the University of Miami. The study was done in conjunction with the Federal University of São Paulo. A total of 43 eyes from 40 patients were elected to participate in the study. RESULTS: The follow-up range was three to 60 months (mean 20 months. The age ranged from 37 to 77 years with a mean of 59. Preoperative visual acuity improved two lines or more in 26 (60.4% eyes, remained the same in 9 (20.9% and got worse in 8 (18.6%. In 10 (23.2% eyes visual acuity improved to 20/40. The study showed to be statistically significant for the improvement of the final visual acuity. Recurrent vitreous hemorrhage was the most frequent postoperative complication found in 12 (27.9% eyes and it was followed by transient anterior chamber reaction in 9 (20.9% eyes. Intraoperative and postoperative complications related to phacoemulsification were rare. IOL capture was found in 2 (4.6% eyes and intraocular lens subluxation in 1 (2.3% eye. CONCLUSION: Combined phacoemulsification with posterior chamber intraocular lens implant and pars plana

  18. OPAL Jet Chamber Prototype

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the dirfferent parts of the tracking system. This piece is a prototype of the jet chambers

  19. Latanoprost ophthalmic solution in the treatment of open angle glaucoma or raised intraocular pressure: a review

    Directory of Open Access Journals (Sweden)

    Andrea Russo

    2009-01-01

    Full Text Available Andrea Russo, Ivano Riva, Teodoro Pizzolante, Federico Noto, Luciano QuarantaCattedra di Malattie dell’Apparato Visivo, Università degli studi di Brescia, USVD “Centro per lo studio del Glaucoma” Spedali Civili di BresciaAbstract: Latanoprost is a prostaglandin F2-alpha isopropyl ester prodrug which is rapidly hydrolyzed by esterases in the cornea to the biologically active latanoprost acid. When latanoprost is topically administered into the eye, the cornea seems to act like as a slow-release depot to the anterior segment. One hour after administration maximum concentration is found in the iris, followed by the anterior chamber and the ciliary body. Despite extensive research, controversy remains about the real mechanism of action of this drug. Immunohistochemical data have shown that the intraocular pressure (IOP reduction with topical prostaglandin F2-alpha is associated with a reduction of collagens within the uveoscleral outflow pathway. Evidence from several experimental and clinical studies suggests that latanoprost is a valuable addition first-line treatment alternatives for glaucoma, ocular hypertension and even angle-closure glaucoma. Strong points are its efficacy, which is demonstrated to be higher than that of brimonidine, dorzolamide and timolol with fewer systemic adverse effects; a convenient administration schedule; and the IOP-controlling pattern, which is relatively flat compared with timolol and dorzolamide, and enables better control in glaucoma progression, since large fluctuations may be associated with the risk of developing glaucoma in untreated ocular hypertensive subjects.Keywords: latanoprost, intraocular pressure, glaucoma, ocular hypertension

  20. Gridded ionization chamber

    International Nuclear Information System (INIS)

    An improved ionization chamber type x-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is disposed adjacent the anode and is maintained at a voltsge intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting toward the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure

  1. ALICE Time Projection Chamber

    CERN Multimedia

    Lippmann, C

    2013-01-01

    The Time Projection Chamber (TPC) is the main device in the ALICE 'central barrel' for the tracking and identification (PID) of charged particles. It has to cope with unprecedented densities of charges particles.

  2. Toxic Test Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — Description/History: Hazardous material test facility Both facilities have 16,000 cubic foot chambers, equipped with 5000 CFM CBR filter systems with an air change...

  3. Calorimetry with flash chambers

    International Nuclear Information System (INIS)

    The flash chambers used in the Fermilab E594 neutrino experiment are described, and their use in a calorimeter discussed. Resolutions obtained with a calibration beam are presented, and comments made about the pattern recognition capabilities of the calorimeter

  4. Bubble chamber: antiproton annihilation

    CERN Multimedia

    1971-01-01

    These images show real particle tracks from the annihilation of an antiproton in the 80 cm Saclay liquid hydrogen bubble chamber. A negative kaon and a neutral kaon are produced in this process, as well as a positive pion. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  5. Gridded Ionization Chamber

    International Nuclear Information System (INIS)

    In the present paper the working principles of a gridded ionization chamber are given, and all the different factors that determine its resolution power are analyzed in detail. One of these devices, built in the Physics Division of the JEN and designed specially for use in measurements of alpha spectroscopy, is described. finally the main applications, in which the chamber can be used, are shown. (Author) 17 refs

  6. Intraocular pressure and tear production in five herbivorous wildlife species.

    Science.gov (United States)

    Ofri, R; Horowitz, I H; Raz, D; Shvartsman, E; Kass, P H

    2002-08-31

    The intraocular pressure and rate of tear production were measured in 18 addax antelopes (Addax nasomaculatus), four impalas (Aepyceros melampus), 11 wide-lipped rhinoceroses (Ceratotherium simum), 10 white-tailed wildebeests (Connochaetes gnou) and seven scimitar-horned oryxes (Oryx dammah). The animals were anaesthetised with an intramuscular injection of etorphine hydrochloride and acepromazine maleate, and the Schirmer tear test I was used to evaluate tear production, and applanation tonometry was used to evaluate the intraocular pressure. The mean (sd) rate of tear production ranged from 17.6 (3.1) mm/minute in the rhinoceros to 28.8 (8.3) mm/minute in the addax. The intraocular pressure ranged from 8.0 (1.2) mmHg in the impala to 32.1 (10.4) mmHg in the rhinoceros. The rate of tear production in the addax and the intraocular pressure in the rhinoceros appear to be the highest values of these variables to have been reported in any species. PMID:12233828

  7. Telemedicine in the control of intra-ocular pressure.

    Science.gov (United States)

    Michelson, G; Striebel, W; Prihoda, W; Schmidt, V

    2000-01-01

    Glaucoma is one of the most common causes of blindness in the Western world and a major risk factor is increased intra-ocular pressure. We therefore used telemedicine in its control. Patients measured their intra-ocular pressure several times a day with a portable instrument and the values were then entered into a portable digital assistant. These data were transmitted by a modem to a central server. If the intra-ocular pressure was pathologically high, an email message was automatically sent to the ophthalmologist. The pressure curve, including a statistical analysis, was displayed in an easily readable chart format. Ten patients with glaucoma participated in a trial. Self-tonometry with telemedicine enabled continuous evaluation of the patient by the ophthalmologist. This approach offered the advantage of controlling the treatment remotely. Advantages for the patient were that the measurements were easily done at home under normal conditions, and the patient could control when the measurement and data transmission would be performed. Telemedicine is a cost-effective technique enabling the early diagnosis of pathologically increased intra-ocular pressure. PMID:10793996

  8. Effect of chymase on intraocular pressure in rabbits.

    Science.gov (United States)

    Konno, Takashi; Maruichi, Midori; Takai, Shinji; Oku, Hidehiro; Sugiyama, Tetsuya; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Ikeda, Tsunehiko; Miyazaki, Mizuo

    2005-11-01

    Chymase is a chymotrypsin-like serine protease that is stored exclusively in the secretory granules of mast cells and converts big endothelins to endothelin-1 (1-31). The aim of this study was to evaluate the effect of chymase on intraocular pressure in rabbits. Chymase injection (3 and 10 mU) resulted in a trend toward increased intraocular pressure and a significant increase in intraocular pressure at a dose of 10 mU compared with the control. A specific chymase inhibitor, Suc-Val-Pro-Phe(P)(OPh)(2), attenuated the ocular hypertension induced by chymase. Endothelin-1 (1-31) also caused ocular hypertension, which was inhibited by a selective endothelin ET(A) receptor antagonist, cyclo(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123). Moreover, chymase-induced ocular hypertension was inhibited by BQ-123. These results suggest that chymase influences the regulation of intraocular pressure, and it is likely that the formation of endothelin-1 (1-31) and subsequent activation of endothelin ET(A) receptors are involved in the development of ocular hypertension induced by chymase. PMID:16253233

  9. Hematoporphyrin derivative photoradiation therapy for the treatment of intraocular tumors

    International Nuclear Information System (INIS)

    Hematoporphyrin derivative (HpD) photoradiation therapy (PRT) is currently being examined for the treatment of intraocular tumors (retinoblastoma and uveal melanoma). HpD is preferentially retained in malignant tissue and tumorcidal action can be induced when HpD is activated with visible red light. Preclinical studies have been conducted using pigmented rabbits having transplanted intraocular tumors. A dye laser system has been used to generate red light (630 nm) for localized irradiation of ocular tissue following I.V. administration of HpD. The authors have previously reported that acute toxicity to normal retina (in the form of retinal necrosis) can be induced by HpD PRT, and that this damage can be limited to the treatment field. The results of current preclinical studies related to long term ocular toxicity, HpD distribution in ocular tissue and intraocular tumor tissue response following HpD PRT are presented. In addition, initial clinical results of intraocular HpD PRT are described

  10. Impact factors on intraocular pressure measurements in healthy subjects.

    NARCIS (Netherlands)

    Theelen, T.; Meulendijks, C.F.M.; Geurts, D.; Leeuwen, A.M. van; Voet, N.B.; Deutman, A.F.

    2004-01-01

    AIM: To evaluate whether intraocular pressure (IOP) calculation by applanation tonometry is determined more essentially by the subject's neck position or by neck constriction. METHODS: 23 right eyes of 23 healthy subjects (12 male, 11 female) were included. IOP was measured by applanation tonometry

  11. Unilateral phacoemulsification and intraocular lens implantation in a dachshund

    OpenAIRE

    Kopala, Robyn L.

    2008-01-01

    A 1.5-year-old, spayed, female dachshund was presented with a cataract and lens-induced uveitis in the left eye. The cataract progressed from immature to hypermature in 4 months. Phacoemulsification and intraocular lens implantation was performed and the dog remains visual in the left eye 1 year post-surgery.

  12. Implantable parylene-based wireless intraocular pressure sensor

    OpenAIRE

    Chen, Po-Jui; Rodger, Damien C.; Saati, Saloomeh; Humayun, Mark S.; Tai, Yu-Chong

    2008-01-01

    This paper presents a novel implantable, wireless, passive pressure sensor for ophthalmic applications. Two sensor designs incorporating surface-micromachined variable capacitor and variable capacitor/inductor are implemented to realize the pressure sensitive components. The sensor is monolithically microfabricated using parylene as a biocompatible structural material in a suitable form factor for increased ease of intraocular implantation. Pressure responses of the mi...

  13. Combined aniridic intraocular lens implantation and vitreoretinal surgery

    Science.gov (United States)

    Mehta, Hijab; Jayadev, Chaitra; Natarajan, S

    2007-01-01

    A 45-year-old man presented with post-traumatic aniridia. We describe the combined surgery done to treat both aniridia and epiretinal membrane simultaneously. A combined aniridia intraocular lens and vitreoretinal surgery was done. The case report highlights the advantage of combined surgery in terms of cost factor and surgical time. PMID:17699956

  14. Combined aniridic intraocular lens implantation and vitreoretinal surgery

    OpenAIRE

    Mehta Hitendra; Mehta Hijab; Jayadev Chaitra; Natarajan S

    2007-01-01

    A 45-year-old man presented with post-traumatic aniridia. We describe the combined surgery done to treat both aniridia and epiretinal membrane simultaneously. A combined aniridia intraocular lens and vitreoretinal surgery was done. The case report highlights the advantage of combined surgery in terms of cost factor and surgical time.

  15. Combined aniridic intraocular lens implantation and vitreoretinal surgery

    Directory of Open Access Journals (Sweden)

    Mehta Hitendra

    2007-01-01

    Full Text Available A 45-year-old man presented with post-traumatic aniridia. We describe the combined surgery done to treat both aniridia and epiretinal membrane simultaneously. A combined aniridia intraocular lens and vitreoretinal surgery was done. The case report highlights the advantage of combined surgery in terms of cost factor and surgical time.

  16. Intraocular inflammation following endotamponade with high-density silicone oil.

    NARCIS (Netherlands)

    Theelen, T.; Tilanus, M.A.D.; Klevering, B.J.

    2004-01-01

    BACKGROUND: The use of a mixture of silicone oil and partially fluorinated alkanes (high-density silicone oil) has recently been suggested as intraocular tamponade in complicated retinal detachment of the inferior quadrants. We describe a series of patients who developed a clinical picture resemblin

  17. The Scales of Gravitational Lensing

    CERN Document Server

    De Paolis, Francesco; Ingrosso, Gabriele; Manni, Luigi; Nucita, Achille; Strafella, Francesco

    2016-01-01

    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.

  18. 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.

  19. Natural wormholes as gravitational lenses

    CERN Document Server

    Cramer, J G; Morris, M S; Visser, M; Benford, G; Landis, G A; Cramer, John G; Forward, Robert L; Morris, Michael S; Visser, Matt; Benford, Gregory; Landis, Geoffrey A

    1995-01-01

    Visser has suggested traversable 3-dimensional wormholes that could plausibly form naturally during Big Bang inflation. A wormhole mouth embedded in high mass density might accrete mass, giving the other mouth a net *negative* mass of unusual gravitational properties. The lensing of such a gravitationally negative anomalous compact halo object (GNACHO) will enhance background stars with a time profile that is observable and qualitatively different from that recently observed for massive compact halo objects (MACHOs) of positive mass. We recommend that MACHO search data be analyzed for GNACHOs.

  20. Weak lensing by galaxy troughs

    Science.gov (United States)

    Gruen, Daniel

    2016-06-01

    Galaxy troughs, i.e. underdensities in the projected galaxy field, are a weak lensing probe of the low density Universe with high signal-to-noise ratio. I present measurements of the radial distortion of background galaxy images and the de-magnification of the CMB by troughs constructed from Dark Energy Survey and Sloan Digital Sky Survey galaxy catalogs. With high statistical significance and a relatively robust modeling, these probe gravity in regimes of density and scale difficult to access for conventional statistics.

  1. Incidência de opacificação de cápsula posterior em pacientes submetidos à facoemulsificação e implante de lentes intra-oculares acrílicas hidrofílicas expansíveis Incidence of posterior capsule opacification in patients submitted to phacoemulsification and expandable acrylic intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Hilton Arcoverde Gonçalves de Medeiros

    2006-06-01

    Full Text Available OBJETIVO: Avaliar prospectivamente os resultados das lentes intra-oculares de polímeros expansíveis implantadas em pacientes submetidos à facoemulsificação, quanto à incidência de opacificação de cápsula posterior, levando em consideração a biocompatibilidade das lentes expansíveis. MÉTODOS: O grupo de estudo foi composto por 830 pacientes, 1.200 olhos, que foram submetidos a facoemulsificação, utilizando a mesma técnica, variando-se apenas o diâmetro da capsulorrexe, pelo mesmo cirurgião, no período de 1998 a 2002, com implante de lente intra-ocular hidrofílica expansível. O acompanhamento médio foi de 2,4 anos, variando de seis meses a quatro anos. RESULTADOS: O número total de opacificação de cápsula posterior foi de 54 casos. CONCLUSÃO: A incidência de opacificação de cápsula posterior encontrada no grupo foi de 4,6%.PURPOSE: To evaluate prospectively the results of expandable acrylic intraocular lenses in patients submitted to phacoemulsification as regard posterior capsule opacification. METHODS: The study group consisted of 830 patients, 1,200 eyes that underwent phacoemulsification from 1998 to 2002, by the same surgeon, using the same technique but with different diameters of capsulorrhexis, with expandable hydrophilic acrylic intraocular lens implantation. The mean follow-up was 2.4 years, ranging from 6 months to 4 years. RESULTS: The total number of posterior capsule opacification was 54 cases. CONCLUSIONS: The incidence of posterior capsule opacification was 4.6% in these patients.

  2. Changes in intraocular pressure and anterior segment morphometry after uneventful phacoemulsification cataract surgery.

    LENUS (Irish Health Repository)

    Dooley, I

    2012-02-01

    PURPOSE: To study changes in anterior segment morphometry after uneventful phacoemulsification cataract surgery, and to investigate whether there is a relationship between any observed changes and intraocular pressure (IOP) reduction after the procedure. METHODS: The anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), central corneal thickness (CCT), and IOP were measured in 101 non-glaucomatous eyes before and after uneventful phacoemulsification cataract surgery. RESULTS: After cataract surgery, the mean ACD, ACV, and ACA values increased by 1.08 mm, 54.4 mm(3), and 13.1 degrees , respectively, and the mean IOP (corrected for CCT) decreased by 3.2 mm Hg. The predictive value of a previously described index (preoperative ACD\\/preoperative IOP (corrected for CCT) or CPD ratio) for IOP (corrected for CCT) reduction after cataract surgery was confirmed, reflected in an r(2) value of 23.3% between these two parameters (P<0.001). Other indices predictive of IOP reduction after cataract surgery were also identified, including preoperative IOP\\/preoperative ACV and preoperative IOP\\/preoperative ACA, reflected in r(2) values of 13.7 and 13.7%, respectively (P<0.001 and P<0.001, respectively). CONCLUSIONS: Our study confirms the predictive value of the CPD ratio for IOP reduction after cataract surgery, and may contribute to the decision-making process in patients with glaucoma or ocular hypertension. Furthermore, two novel indices of preoperative parameters that are predictive for IOP reduction after cataract surgery were identified, and enhance our understanding of the mechanisms underlying IOP changes after this procedure.

  3. Aplanatic lenses revisited: the full landscape.

    Science.gov (United States)

    Mashaal, Heylal; Feuermann, Daniel; Gordon, Jeffrey M

    2016-04-01

    The full scope of solutions for dual-contour aplanatic lenses that can approach the basic limit for radiation transfer are identified, analyzed, and illustrated. Complementary solutions are shown to yield lenses that are either monolithic or have two refractive contours separated by an air gap. The performance of a promising representative design for LED collimation is presented. PMID:27139654

  4. Long-term visual outcomes after Crystalens® HD intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Karavitaki AE

    2014-05-01

    Full Text Available Alexandra E Karavitaki, Ioannis G Pallikaris, Sophia I Panagopoulou, George A Kounis, George Kontadakis, George D KymionisInstitute of Vision and Optics, University of Crete, Crete, GreecePurpose: Our purpose was to evaluate the long-term visual outcomes after bilateral implantation of Crystalens® HD (Bausch and Lomb, Inc. accommodative intraocular lenses.Methods: In this study, 25 patients (50 eyes who underwent cataract surgery and bilateral Crystalens HD accommodative intraocular lens implantation were included. The Crystalens HD lens was implanted in the bag in both eyes, without any intra- or postoperative complications. The visual parameters measured before and after surgery were: uncorrected distance visual acuity, corrected distance visual acuity (CDVA (using the Early Diabetic Retinopathy Study [EDTRS] logMAR charts, uncorrected intermediate visual acuity, and uncorrected near visual acuity using a Birkhäuser reading chart, at a distance of 66 cm and 33 cm for intermediate and near vision, respectively, directly illuminated by a lamp of 60 watts. After surgery, the patients were evaluated at 1, 3, 6, 12, 24, and 36 months.Results: The mean age was 68.70±7.1 (range: 54 to 83 years. The mean follow-up was 42.72±0.49 (range: 42.33 to 43.27 months. The uncorrected distance visual acuity improved from 0.56±0.41 (range: 0 to 2 preoperatively to 0.19±0.13 (range: 0 to 0.38 (logMAR scale at the last follow-up visit, and the CDVA improved from 0.17±0.18 (range: 0 to 0.7 preoperatively to 0.05±0.05 (range: −0.02 to 0.22 at the last follow-up visit. No eyes lost lines of CDVA during the follow-up period, while 54% of patients gained one or more lines of CDVA. The uncorrected intermediate and near visual acuity was J2 or better in 71% and 69% of our patients, respectively.Conclusion: Crystalens HD implantation seems to provide an improvement in visual acuity for far, intermediate, and near distances.Keywords: presbyopia, accommodation

  5. Aberrations in asymmetrical electron lenses

    International Nuclear Information System (INIS)

    Starting from well established knowledge in light-optics we explore the question if electron-optical aberration can be improved in asymmetrical electron lenses. We show that spherical as well as chromatic aberration coefficients are reduced in asymmetric electrostatic einzel lenses when the center electrode is moved away from the center position towards the entrance electrode. Relative improvements up to 40% for both the chromatic and the spherical aberration coefficients can be obtained. We use analytical and numerical calculations to confirm this result for exemplary cases of a lens with fixed length and working distance. The agreement of the two calculation methods is very good. We then derive an estimate for the electron-optical aberration coefficients from light-optics. The derived expressions for chromatic and spherical aberrations are somewhat simpler than the ones derived from electron-optics as they involve integrals only over the electrostatic potential, not over the electron paths. The estimated formulas still agree well with the electron optical calculations. Overall, we are tempted to suggest that the enormous knowledge base of light optics can provide considerable guidance for electron-optical applications. -- Highlights: ► Develops the analogy between light and electron optics in aberration calculations. ► Optimized spherical and chromatic aberrations for an electrostatic einzel lens. ► Comparison between analytic and numerical aberration calculations.

  6. Aberrations in asymmetrical electron lenses.

    Science.gov (United States)

    Fitzgerald, J P S; Word, R C; Könenkamp, R

    2012-08-01

    Starting from well established knowledge in light-optics we explore the question if electron-optical aberration can be improved in asymmetrical electron lenses. We show that spherical as well as chromatic aberration coefficients are reduced in asymmetric electrostatic einzel lenses when the center electrode is moved away from the center position towards the entrance electrode. Relative improvements up to 40% for both the chromatic and the spherical aberration coefficients can be obtained. We use analytical and numerical calculations to confirm this result for exemplary cases of a lens with fixed length and working distance. The agreement of the two calculation methods is very good. We then derive an estimate for the electron-optical aberration coefficients from light-optics. The derived expressions for chromatic and spherical aberrations are somewhat simpler than the ones derived from electron-optics as they involve integrals only over the electrostatic potential, not over the electron paths. The estimated formulas still agree well with the electron optical calculations. Overall, we are tempted to suggest that the enormous knowledge base of light optics can provide considerable guidance for electron-optical applications. PMID:22206603

  7. Cosmology with Strong Lensing Systems

    CERN Document Server

    Cao, Shuo; Gavazzi, Raphaël; Piórkowska, Aleksandra; Zhu, Zong-Hong

    2015-01-01

    In this paper, we assemble a catalog of 118 strong gravitational lensing systems from SLACS, BELLS, LSD and SL2S surveys and use them to constrain the cosmic equation of state. In particular we consider two cases of dark energy phenomenology: $XCDM$ model where dark energy is modeled by a fluid with constant $w$ equation of state parameter and in Chevalier - Polarski - Linder (CPL) parametrization where $w$ is allowed to evolve with redshift: $w(z) = w_0 + w_1 \\frac{z}{1+z}$. We assume spherically symmetric mass distribution in lensing galaxies, but relax the rigid assumption of SIS model in favor to more general power-law index $\\gamma$, also allowing it to evolve with redshifts $\\gamma(z)$. Our results for the $XCDM$ cosmology show the agreement with values (concerning both $w$ and $\\gamma$ parameters) obtained by other authors. We go further and constrain the CPL parameters jointly with $\\gamma(z)$. The resulting confidence regions for the parameters are much better than those obtained with a similar metho...

  8. Gravitational Lensing: Strong, Weak and Micro

    CERN Document Server

    Schneider, Peter; Wambsganss, Joachim

    2006-01-01

    The theory, observations, and applications of gravitational lensing constitute one of the most rapidly growing branches of astrophysics. The gravitational deflection of light generated by mass concentrations along a light path produces magnification, multiplicity, and distortion of images and delays photon propagation from one line of sight relative to another. The huge amount of scientific work on gravitational lensing produced over the last decade has clearly revealed its already substantial and wide impact and its potential for future astrophysical applications. The up-to-date contributions in this book are based on the lecture notes of the 33rd Saas–Fee Advanced Course of the Swiss Society of Astronomy and Astrophysics, entitled Gravitational Lensing: Strong, Weak, and Micro. The book comprises four complementary parts, written by leading experts in the field, constituting a genuine textbook about gravitational lensing: • Peter Schneider – Part 1: Introduction to Gravitational Lensing and Cosmology ...

  9. New lensed quasars from the MUSCLES survey

    CERN Document Server

    Jackson, Neal; Ofek, Eran O; Shin, Min-Su

    2011-01-01

    Gravitational lens systems containing lensed quasars are important as cosmological probes, as diagnostics of structural properties of the lensing galaxies and as tools to study the quasars themselves. The largest lensed quasar sample is the SDSS Quasar Lens Search, drawn from the Sloan Digital Sky Survey (SDSS). We are attempting to extend this survey using observations of lens candidates selected from a combination of the quasar sample from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). This adds somewhat higher image quality together with a wider range of wavelength for the selection process. In previous pilot surveys we observed 5 objects, finding 2 lenses; here we present further observations of 20 objects in which we find 4 lenses, of which 2 are independently discovered in SQLS (in preparation). Following earlier work on the combination of these two surveys, we have refined our method and find that use of a colour-separation diagnostic, where we select for separations between components which...

  10. Image processing challenges in weak gravitational lensing

    CERN Document Server

    Amara, Adam

    2011-01-01

    The field of weak gravitational lensing, which measures the basic properties of the Universe by studying the way that light from distant galaxies is perturbed as it travels towards us, is a very active field in astronomy. This short article presents a broad overview of the field, including some of the important questions that cosmologists are trying to address, such as understanding the nature of dark energy and dark matter. To do this, there is an increasing feeling within the weak lensing community that other disciplines, such as computer science, machine learning, signal processing and image processing, have the expertise that would bring enormous advantage if channelled into lensing studies. To illustrate this point, the article below outlines some of the key steps in a weak lensing analysis chain. The challenges are distinct at each step, but each could benefit from ideas developed in the signal processing domain. This article also gives a brief overview of current and planned lensing experiments that wi...

  11. Gravitational Lensing of Cosmic Microwave Background Polarization

    CERN Document Server

    Ade, P A R; Anthony, A E; Arnold, K; Barron, D; Boettger, D; Borrill, J; Chapman, S; Chinone, Y; Dobbs, M; Elleflot, T; Errard, J; Fabbian, G; Feng, C; Flanigan, D; Gilbert, A; Grainger, W; Halverson, N W; Hasegawa, M; Hattori, K; Hazumi, M; Holzapfel, W L; Hori, Y; Howard, J; Hyland, P; Inoue, Y; Jaehnig, G C; Jaffe, A; Keating, B; Kermish, Z; Keskitalo, R; Kisner, T; Jeune, M Le; Lee, A T; Linder, E; Lungu, M; Matsuda, F; Matsumura, T; Meng, X; Miller, N J; Morii, H; Moyerman, S; Myers, M J; Navaroli, M; Nishino, H; Paar, H; Peloton, J; Quealy, E; Rebeiz, G; Reichardt, C L; Richards, P L; Ross, C; Schanning, I; Schenck, D E; Sherwin, B; Shimizu, A; Shimmin, C; Shimon, M; Siritanasak, P; Smecher, G; Spieler, H; Stebor, N; Steinbach, B; Stompor, R; Suzuki, A; Takakura, S; Tomaru, T; Wilson, B; Yadav, A; Zahn, O

    2013-01-01

    Primary fluctuations in both temperature and polarization of the Cosmic Microwave Background (CMB) reflect the properties of the Universe from the Big Bang until the photons decoupled from matter 380,000 years later. These primary fluctuations are then lensed by large-scale structures (such as clusters of galaxies and filaments of dark matter), with the result that the distribution and properties of dark matter, including the masses of neutrinos, can be determined more accurately by extracting the lensing information than through studying the primary fluctuations alone. Polarization lensing can give cleaner, higher resolution results than temperature lensing. The correlation of lensed CMB polarization with large-scale structure, traced through the Cosmic Infrared Background, was recently detected; however, this correlation does not trace all structure and depends on the relationship between the infrared flux from the galaxies and the underlying mass distribution. Here we report the detection of gravitational ...

  12. Time Delay in Swiss Cheese Gravitational Lensing

    CERN Document Server

    Chen, Bin; Dai, Xinyu

    2010-01-01

    We compute time delays for gravitational lensing in a flat LambdaCDM Swiss cheese universe. We assume a primary and secondary pair of light rays are deflected by a single point mass condensation described by a Kottler metric (Schwarzschild with Lambda) embedded in an otherwise homogeneous cosmology. We find that the cosmological constant's effect on the difference in arrival times is non-linear and at most around 0.002% for a large cluster lens; however, we find differences from time delays predicted by conventional linear lensing theory that can reach ~4% for these large lenses. The differences in predicted delay times are due to the failure of conventional lensing to incorporate the lensing mass into the mean mass density of the universe.

  13. [Corneal metabolism with contact lenses in competitive sports].

    Science.gov (United States)

    Schnell, D; Khaireddin, R

    2013-06-01

    The corneal metabolism during the use of contact lenses plays an important role for permanent corneal health, especially in competitive sports. Thus, it is important to understand the steps of corneal metabolism in general and during highly competitive sports activity in particular. The aim of this review is to summarize the current knowledge on physiological and biochemical effects of contact lens wear. Of the energy requirements of the cornea 75 % is supplied by aerobic processes; therefore, the eye needs the highest possible amount of oxygen and sufficient glucose which can be obtained from external air and to a lesser degree from within the anterior chamber. If the oxygen supply is too low this results in hypoxic edema. Fitting athletes with contact lenses must still be viewed with caution as the visual needs of athletes are usually much more demanding than those of the general public. An indiscriminate choice of lens design can adversely affect athletic performance and may even create a hazardous situation. An intelligent choice of contact lens can provide some subtle advantages that may improve athletic performance and provide the decisive margin for victory. PMID:23783993

  14. Detection of purkinje images for automatic positioning of fixation target and interferometric measurements of anterior eye chamber

    OpenAIRE

    Almeida, Mariana Quelhas Dias Rodrigues

    2012-01-01

    In cataract surgery, the eye’s natural lens is removed because it has gone opaque and doesn’t allow clear vision any longer. To maintain the eye’s optical power, a new artificial lens must be inserted. Called Intraocular Lens (IOL), it needs to be modelled in order to have the correct refractive power to substitute the natural lens. Calculating the refractive power of this substitution lens requires precise anterior eye chamber measurements. An interferometry equipment, the AC Master from ...

  15. Evaluation of high volume extracapsular cataract extraction with posterior chamber lens implantation in Sierra Leone, west Africa.

    OpenAIRE

    Cook, N J

    1996-01-01

    AIMS: Intraocular lens (IOP) implantation in sub-Saharan Africa is not the routine procedure of choice in the treatment of cataract. Previous series consist of small numbers of selected patients. The purpose of this study was to evaluate routine posterior chamber lens implantation in large numbers of consecutive patients. METHODS: 1059 cataract extractions with planned IOL (744 patients) were performed over a 1 year period from August 1993 to July 1994. RESULTS: 94.6% (1002) of eyes showed an...

  16. Target Chamber Manipulator

    Science.gov (United States)

    Tantillo, Anthony; Watson, Matthew

    2015-11-01

    A system has been developed to allow remote actuation of sensors in a high vacuum target chamber used with a particle accelerator. Typically, sensors of various types are placed into the target chamber at specific radial and angular positions relative to the beam line and target. The chamber is then evacuated and the experiments are performed for those sensor positions. Then, the chamber is opened, the sensors are repositioned to new angles or radii, and the process is repeated, with a separate pump-down cycle for each set of sensor positions. The new sensor positioning system allows scientists to pre-set the radii of up to a dozen sensors, and then remotely actuate their angular positions without breaking the vacuum of the target chamber. This reduces the time required to reposition sensors from 6 hours to 1 minute. The sensors are placed into one of two tracks that are separately actuated using vacuum-grade stepping motors. The positions of the sensors are verified using absolute optical rotary encoders, and the positions are accurate to 0.5 degrees. The positions of the sensors are electronically recorded and time-stamped after every change. User control is through a GUI using LabVIEW.

  17. The KLOE drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Adinolfi, M.; Aloisio, A.; Ambrosino, F.; Andryakov, A.; Antonelli, A.; Antonelli, M.; Anulli, F.; Bacci, C.; Bankamp, A.; Barbiellini, G.; Bellini, F.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Bulychjov, S.A.; Cabibbo, G.; Calcaterra, A.; Caloi, R.; Campana, P.; Capon, G.; Carboni, G.; Cardini, A.; Casarsa, M.; Cataldi, G.; Ceradini, F.; Cervelli, F.; Cevenini, F.; Chiefari, G.; Ciambrone, P.; Conetti, S.; Conticelli, S.; Lucia, E. De; Robertis, G. De; Sangro, R. De; Simone, P. De; Zorzi, G. De; Dell' Agnello, S.; Denig, A.; Domenico, A. Di; Donato, C. Di; Falco, S. Di; Doria, A.; Drago, E.; Elia, V.; Erriquez, O.; Farilla, A.; Felici, G.; Ferrari, A.; Ferrer, M.L.; Finocchiaro, G.; Forti, C.; Franceschi, A.; Franzini, P.; Gao, M.L.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Golovatyuk, V.; Gorini, E.; Grancagnolo, F.; Grandegger, W.; Graziani, E.; Guarnaccia, P.; Hagel, U.V.; Han, H.G.; Han, S.W.; Huang, X.; Incagli, M.; Ingrosso, L.; Jang, Y.Y.; Kim, W.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Lomtadze, F.; Luisi, C.; Mao, C.S.; Martemianov, M.; Matsyuk, M.; Mei, W.; Merola, L.; Messi, R.; Miscetti, S.; Moalem, A.; Moccia, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nedosekin, A.; Panareo, M.; Pacciani, L.; Pages, P.; Palutan, M.; Paoluzi, L.; Pasqualucci, E.; Passalacqua, L.; Passaseo, M.; Passeri, A.; Patera, V.; Petrolo, E.; Petrucci, G.; Picca, D.; Pirozzi, G.; Pistillo, C.; Pollack, M.; Pontecorvo, L.; Primavera, M.; Ruggieri, F.; Santangelo, P.; Santovetti, E.; Saracino, G.; Schamberger, R.D.; Schwick, C.; Sciascia, B.; Sciubba, A.; Scuri, F.; Sfiligoi, I.; Shan, J.; Silano, P.; Spadaro, T.; Spagnolo, S.; Spiriti, E.; Stanescu, C.; Tong, G.L.; Tortora, L.; Valente, E.; Valente, P. E-mail: paolo.valente@lnf.infn.it; Valeriani, B.; Venanzoni, G.; Veneziano, S.; Wu, Y.; Xie, Y.G.; Zhao, P.P.; Zhou, Y

    2001-04-01

    The tracking detector of the KLOE experiment is 4 m diameter, 3.3 m length drift chamber, designed to contain a large fraction of the decays of low-energy K{sub L} produced at the Frascati DAPHINE phi-factory. The chamber is made by a thin carbon fiber structure and operated with a helium-based gas mixture in order to minimise conversion of low-energy photons and multiple scattering inside the sensitive volume. The tracking information is provided by 58 layers of stereo wires defing 12,582 cells, 2x2 cm{sup 2} in size in the 12 innermost layers and 3x3 cm{sup 2} in the outer ones. Details of the chamber design, calibration procedure and tracking performances are presented.

  18. The KLOE drift chamber

    International Nuclear Information System (INIS)

    The tracking detector of the KLOE experiment is 4 m diameter, 3.3 m length drift chamber, designed to contain a large fraction of the decays of low-energy KL produced at the Frascati DAPHINE phi-factory. The chamber is made by a thin carbon fiber structure and operated with a helium-based gas mixture in order to minimise conversion of low-energy photons and multiple scattering inside the sensitive volume. The tracking information is provided by 58 layers of stereo wires defing 12,582 cells, 2x2 cm2 in size in the 12 innermost layers and 3x3 cm2 in the outer ones. Details of the chamber design, calibration procedure and tracking performances are presented

  19. Automated Electrostatics Environmental Chamber

    Science.gov (United States)

    Calle, Carlos; Lewis, Dean C.; Buchanan, Randy K.; Buchanan, Aubri

    2005-01-01

    The Mars Electrostatics Chamber (MEC) is an environmental chamber designed primarily to create atmospheric conditions like those at the surface of Mars to support experiments on electrostatic effects in the Martian environment. The chamber is equipped with a vacuum system, a cryogenic cooling system, an atmospheric-gas replenishing and analysis system, and a computerized control system that can be programmed by the user and that provides both automation and options for manual control. The control system can be set to maintain steady Mars-like conditions or to impose temperature and pressure variations of a Mars diurnal cycle at any given season and latitude. In addition, the MEC can be used in other areas of research because it can create steady or varying atmospheric conditions anywhere within the wide temperature, pressure, and composition ranges between the extremes of Mars-like and Earth-like conditions.

  20. Effects of systemic domestic recombinant human erythropoietin on HIF-1α expression in the retina in a rabbit model of acute high intraocular pressure

    Institute of Scientific and Technical Information of China (English)

    Yan-ping Song; Jian-ming Wang; Mei Zhang; Na Hui; Shi-ping Zhao; Kai Hu

    2009-01-01

    Objective To observe the expression of hypoxia inducible faetor-1α (HIF-1α) in the retina of rabbits with acute high intraocular pressure and to investigate the mechanism of systemic domestic recombinant human erythropoietin (rhEPO) protecting the retina from ischemia-reperfusion injury. Methods First, control group and model group were established in rabbit eyes. The acute high intraocular pressure model was established by saline perfusion into anterior chamber, and then hypodermic injection of domestic rhEPO was made. HIF-1α protein in the retina was observed by immunohistochemical staining method on days 1, 3, 7 and 14 after retinal ischemla-reperfusion, respectively. Results No cells with HIF-la positive expression were observed in the retina of the control group. Ceils with HIF-1α positive expression in the model group outnumbered those in the control group (P < 0. 01). The resemblance pattern occurred in EPO group but its degree was slightly greater than that in the model group from day 3 after ischemia-reperfusion (P<0.05). Conclusion Domestic rhEPO can down-regulate the expression of HIF-1α in the retina with acute high intraocular pressure, which may be one of the mechanisms that rhEPO protects the retina from ischemia-reperfusion injury.

  1. Clinical observation of small-incision extracapsular cataract extraction with intraocular lens implantation for the treatment of cataract in the sight restoration project

    Directory of Open Access Journals (Sweden)

    Xiao-Jian Cheng

    2014-04-01

    Full Text Available AIM: To analyze the clinical effects of small-incision extracapsular cataract extraction with intraocular lens implantation for the treatment of cataract.METHODS:Totally 642 cases 676 eyes of cataract were treated by small-incision extracapsular cataract extraction with intraocular lens implantation. Complication during and after operations and postoperative visual acuity was observed.RESULTS:Visual acuity of 670 eyes was ≥0.05 and off-blindness rate was 99.11%, and there was 627 eyes ≥0.3 and the off-disability rate was 92.75% after 1mo. Rupture of posterior capsule during surgery occurred in 24 eyes. Fifty-four eyes were corneal edema, and anterior chamber exudation were 26 eyes, and 23 eyes were hypertension after operation. CONCLUSION: There are a little complications during and after operation for cataract treated by small-incision extracapsular cataract extraction with intraocular lens implantation. Patients have good recovery after operation. This operation does not need high-standard equipments and is suitable in the sight restoration project.

  2. Adherence of Pseudomonas aeruginosa to contact lenses

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. Strong Lensing by Binary Galaxies

    CERN Document Server

    Shin, E M

    2008-01-01

    We study the problem of gravitational lensing by binary galaxies, idealized as two isothermal spheres. In a wide binary, each galaxy possesses individual tangential, nearly astroidal, caustics and roundish radial caustics. As the separation of the binary is made smaller, the caustics undergo a sequence of metamorphoses. The first metamorphosis occurs when the tangential caustics merge to form a single six-cusped caustic, lying interior to the radial caustics. At still smaller separations, the six-cusped caustic undergoes the second metamorphosis and splits into a four-cusped caustic and two three-cusped caustics, which shrink to zero size (an elliptic umbilic catastrophe) before they enlarge again and move away from the origin perpendicular to the binary axis. Finally, a third metamorphosis occurs as the three-cusp caustics join the radial caustics, leaving an inner distorted astroid caustic enclosed by two outer caustics. The maximum number of images possible is 7. Classifying the multiple imaging according ...

  5. Gravitational lensing in observational cosmology

    Science.gov (United States)

    Nottale, L.

    This paper reviews some previous theoretical and observational results concerning the various effects of gravitational lensing, and also presents still unpublished results in this field. The theoretical section deals with the Optical Scalar Equation (OSE) approach. We recall the form of these equations, which relate the deformations of the cross sectional area of a light beam to the material and energetic distribution it encounters, via the two basic contributions to lensing, the matter or Ricci term and the shear term. The introduction of a new distance, the optical distance, allows to write the OSE in a simplified way from which new solutions are easily derived. We demonstrate here that a general form may be obtained for the amplification formula in the exact relativistic treatment, provided the Universe is assumed to be Friedmannian in the mean. New results are also presented concerning the probability distribution of amplifications, the relation from matter term to shear terms (the first ones give the mean of the second ones) and the problem of energy conservation. We recall how our method let to an analytical formula yielding the amplification by any number of lenses placed anywhere along the line of sight and present new general solutions for lensing by large scale density inhomogeneities. The gravitational redshift effects are also considered, either due to the crossing by photons of inhomogeneities, or intrinsic to them ; generalized solutions to the last problem are given. Some observational evidence concerning various lensing effects, either statistical or applying to individual sources, are considered. We first recall how the dependence of the amplification formula on the various physical parameters points towards the optimisation of lensing by very rich clusters of galaxies lying at redshifts around 0.7, which may give rise to very large amplifications for reasonable values of the density parameter. Recent results concerning a statistical effect of

  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. Edge shape and comfort of rigid lenses.

    Science.gov (United States)

    La Hood, D

    1988-08-01

    One of the main factors determining the comfort of a rigid contact lens is the shape of the edge. The comfort of four different contact lens edge shapes was assessed with four unadapted subjects in a randomized masked trial. Lenses with well rounded anterior edge profiles were found to be significantly more comfortable than lenses with square anterior edges. There was no significant difference in subjective comfort between a rounded and square posterior edge profile. The results suggest that the interaction of the edge with the eyelid is more important in determining comfort than edge effects on the cornea, when lenses are fitted according to a corneal alignment philosophy. PMID:3177585

  8. Wettability and silicone hydrogel lenses: a review.

    Science.gov (United States)

    Keir, Nancy; Jones, Lyndon

    2013-01-01

    One of the major breakthroughs in the development of silicone hydrogel contact lenses has related to the ability of manufacturers to overcome the surface hydrophobicity that occurred with silicone elastomer lenses. However, the wettability of silicone hydrogel lenses continues to be of interest as a potential link between in vivo lens performance and contact lens-related comfort. This article will review some of the knowledge we have gained in the area of contact lens wettability over the past decade and will discuss some of the challenges related to its measurement. PMID:23274760

  9. Tevatron Electron Lenses: Design and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir; /Fermilab; Bishofberger, Kip; /Los Alamos; Kamerdzhiev, Vsevolod; /Fermilab; Kozub, Sergei; /Serpukhov, IHEP; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab /SLAC /Fermilab /Serpukhov, IHEP /Novosibirsk, IYF /Serpukhov, IHEP /Fermilab

    2008-08-01

    The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  10. Lensing convergence in galaxy redshift surveys

    CERN Document Server

    Cardona, Wilmar; Kunz, Martin; Montanari, Francesco

    2016-01-01

    In this letter we demonstrate the importance of including the lensing contribution in galaxy clustering analyses with large galaxy redshift surveys. It is well known that radial cross-correlations between different redshift bins of galaxy surveys are dominated by lensing. But we show here that also neglecting lensing in the auto-correlations within one bin severely biases cosmological parameter estimation with redshift surveys. It leads to significant shifts for several cosmological parameters, most notably the scalar amplitude, the scalar spectral index and in particular the neutrino mass scale. Especially the latter parameter is one of the main targets of future galaxy surveys.

  11. Weak Lensing: Dark Matter, Dark Energy

    International Nuclear Information System (INIS)

    The light rays from distant galaxies are deflected by massive structures along the line of sight, causing the galaxy images to be distorted. Measurements of these distortions, known as weak lensing, provide a way of measuring the distribution of dark matter as well as the spatial geometry of the universe. I will describe the ideas underlying this approach to cosmology. With planned large imaging surveys, weak lensing is a powerful probe of dark energy. I will discuss the observational challenges ahead and recent progress in developing multiple, complementary approaches to lensing measurements.

  12. Nanofocusing refractive X-ray lenses

    International Nuclear Information System (INIS)

    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

  13. Twin axial vortices generated by Fibonacci lenses.

    Science.gov (United States)

    Calatayud, Arnau; Ferrando, Vicente; Remón, Laura; Furlan, Walter D; Monsoriu, Juan A

    2013-04-22

    Optical vortex beams, generated by Diffractive Optical Elements (DOEs), are capable of creating optical traps and other multi-functional micromanipulators for very specific tasks in the microscopic scale. Using the Fibonacci sequence, we have discovered a new family of DOEs that inherently behave as bifocal vortex lenses, and where the ratio of the two focal distances approaches the golden mean. The disctintive optical properties of these Fibonacci vortex lenses are experimentally demonstrated. We believe that the versatility and potential scalability of these lenses may allow for new applications in micro and nanophotonics. PMID:23609732

  14. An ultralow power wireless intraocular pressure monitoring system

    International Nuclear Information System (INIS)

    This paper describes an ultralow power wireless intraocular pressure (IOP) monitoring system that is dedicated to sensing and transferring intraocular pressure of glaucoma patients. Our system is comprised of a capacitive pressure sensor, an application-specific integrated circuit, which is designed on the SMIC 180 nm process, and a dipole antenna. The system is wirelessly powered and demonstrates a power consumption of 7.56 μW at 1.24 V during continuous monitoring, a significant reduction in active power dissipation compared to existing work. The input RF sensitivity is −13 dBm. A significant reduction in input RF sensitivity results from the reduction of mismatch time of the ASK modulation caused by FM0 encoding. The system exhibits an average error of ± 1.5 mmHg in measured pressure. Finally, a complete IOP system is demonstrated in the real biological environment, showing a successful reading of the pressure of an eye. (semiconductor integrated circuits)

  15. Wire chamber conference

    International Nuclear Information System (INIS)

    This booklet contains program and the abstracts of the papers presented at the conference, most of them dealing with performance testing of various types of wire chambers. The publication of proceedings is planned as a special issue of 'Nuclear instruments and methods' later on. All abstracts are in English. An author index for the book of abstracts is given. (A.N.)

  16. Scanning bubble chamber pictures

    CERN Multimedia

    1974-01-01

    These were taken at the 2 m hydrogen bubble chamber. The photo shows an early Shiva system where the pre-measurements needed to qualify the event were done manually (cf photo 7408136X). The scanning tables were located in bld. 12. Gilberte Saulmier sits on foreground, Inge Arents at centre.

  17. LEP Vacuum Chamber

    CERN Multimedia

    1983-01-01

    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  18. Drift chamber detectors

    International Nuclear Information System (INIS)

    A review of High Energy Physics detectors based on drift chambers is presented. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysied, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author)

  19. LEP vacuum chamber, prototype

    CERN Multimedia

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  20. Intraocular Pressure Following Intravitreal Injection of Triamcinolone Acetonide§

    OpenAIRE

    Ansari, Ejaz A; Ali, N

    2008-01-01

    Background: To investigate the intraocular pressure (IOP) response following intravitreal injection of triamcinolone acetonide. Methods: This retrospective consecutive non-comparative case series study included 41 patients (52 eyes) (19 male, 22 female, mean age 64.1 ± 13.44; range 22 – 85 years) with progressive exudative ARMD (n = 10 eyes) or diffuse diabetic macular oedema (42 eyes), who received one or more intravitreal injection(s) of 4 mg triamcinolone acetonide. Results: IOP increased ...

  1. Intraocular Pressure And Its Determinants In Tehran Population

    OpenAIRE

    Kashi AH; Fotouhil A; Hashemi H.; Mohammadl K

    2005-01-01

    Background: The aim of this study was to provide data, on the distribution or intraocular pressure (IOP) in Tehran population. Materials and Methods: Through a population-based, cross-sectional study, a total of 4565 Tehran citizens were studied in the Tehran Eye Study. The findings of the participants (n=3834) 10 years and older free of glaucoma diagnosis or suspicion who had undergone applanation tonometry examination are presented. All participants received a standardized protocol included...

  2. Black intraocular lens: another cosmetic approach to leukocoria

    OpenAIRE

    Pedrosa, C; Pina, S.; Azevedo, A.; Pêgo, P; Feijóo, B; Prieto, I

    2012-01-01

    Purpose – To present a case report of a black intraocular lens implantation for cosmetic improvement of a blind eye with leukocoria. Setting – Ophthalmology Department - Professor Dr. Fernando Fonseca Hospital, EPE - Amadora, Lisboa, Portugal Methods – We report a 32-year-old woman who was evaluated because of the undesired cosmetic appearance of her amblyopic left eye with exotropia and leukocoria due to traumatic cataract and total retinal detachment during childhood. The Examination ...

  3. Increased Intraocular Pressure after Extensive Conjunctival Removal: A Case Report

    OpenAIRE

    Lee, Young Rok; Na, Jung Hwa; Kim, Jae Yong; Sung, Kyung Rim

    2013-01-01

    A 50-year-old woman, who had undergone extensive removal of conjunctiva on the right eye for cosmetic purposes at a local clinic 8 months prior to presentation, was referred for uncontrolled intraocular pressure (IOP) elevation (up to 38 mmHg) despite maximal medical treatment. The superior and inferior conjunctival and episcleral vessels were severely engorged and the nasal and temporal bulbar conjunctival areas were covered with an avascular epithelium. Gonioscopic examination revealed an o...

  4. Visual functional changes during acute elevation of intraocular pressure

    Institute of Scientific and Technical Information of China (English)

    Tian-De SHOU

    2006-01-01

    Glaucoma is closely related to elevation of intraocular pressure (IOP). Many studies have done on the effect of chronic elevation of IOP on the retina and optic nerve, but less attention was paid to the effect of acute elevated IOP. Here we briefly review experimental studies on functional changes of the visual system from the retina to the visual cortex under acute elevated IOP condition, which is similar to that of acute primary angle-closure glaucoma.

  5. Composition of intraocular foreign bodies: experimental study of ultrasonographic presentation

    Directory of Open Access Journals (Sweden)

    Márcio Augusto Nogueira Costa

    2013-02-01

    Full Text Available PURPOSE: To investigate the reliability of ultrasound in determining the size and identify the sonographic features and artifacts generated by intraocular foreign bodies of different materials. METHODS: Experimental study using 36 enucleated porcine eyes. Fragments of nine different compositions (wood, glass, plastic, cardboard, iron, aluminum, lead, powder and concrete and similar dimensions (4 mm were implanted via scleral incision into the vitreous cavity of 36 porcine eyes, four eyes were used for each material. Ultrasound examination was performed in all eyes using the contact technique, conductive gel and 10-MHz transducer (EZScan, Sonomed. RESULTS: Considering the material fragments of gunpowder, lead, concrete, aluminum, wood and glass, the size determined by ultrasound was considered statistically similar to the actual size. The material iron presented ultrasound-determined dimension statistically smaller than its actual size. Cardboard and plastic materials showed ultrasound-determined measurements far greater than the actual. All fragments of intraocular foreign bodies demonstrated hyper-reflective interfaces, irrespective of their composition. Whereas the artifacts generated by different materials, it was found that the materials iron, aluminum and lead showed reverberation of great extent. The material wood showed no reverberation. The length of the reverberation artifact for the materials iron, glass, aluminum and cardboard was lower when compared to other materials. All materials presented posterior shadowing artifact, with the exception of aluminum. CONCLUSION: Ultrasonography was considered a reliable technique to determine the size of intraocular foreign bodies in pigs, with little influence caused by its composition. Ultrasound artifacts generated were considered material-dependent and can assist the examiner to identify the nature of a foreign body of unknown etiology. Ultrasonography aided the surgeon to identify, locate and

  6. PSYCHOLOGICAL REACTIONS TO CATARACT SURGERY WITH INTRAOCULAR LENS IMPLANTATION

    OpenAIRE

    Chaudhury, S.; Chakraborty, P.K.; Gurunadh, V.S.; Ratha, P.

    1995-01-01

    A prospective study of fifty patients who underwent cataract surgery with intraocular lens (IOL) implantation was undertaken. Factors aggravating and allaying pre-operative, intra-operative and post-operative anxiety were studied A good doctor-patient relations/lip, confidence in the ophthalmologist, and knowledge of successful surgery with IOL implantation in an acquaintance were the major anxiety relieving factors. The main anxiety provoking factors were concerns about the success of surger...

  7. An Unusual Case of Marble Intraocular Foreign Body

    OpenAIRE

    Omoti Afekhide; Dawodu Oseluese; Ogbeide Osesogie

    2008-01-01

    This report presents a case of marble intraocular foreign body that developed toxic complications during surgery. The patient is a 25 years old male who presented to the University of Benin Teaching Hospital with a history of trauma to the right eye while cutting marble. He was examined, had an ocular ultrasound scan and subsequently had an extracapsular cataract extraction. His visual acuity in the right eye was light perception. There was an entry point on the cornea, the lens was opaque, t...

  8. Intravitreal triamcinolone for intraocular inflammation and associated macular edema

    Directory of Open Access Journals (Sweden)

    Steven M Couch

    2008-11-01

    Full Text Available Steven M Couch, Sophie J BakriMayo Clinic Department of Ophthalmology, Mayo Clinic, Rochester, MN, USAAbstract: Triamcinolone acetonide (TA is a corticosteroid that has many uses in the treatment of ocular diseases because of its potent anti-inflammatory and anti-permeability actions. Intraocular inflammation broadly referred to as uveitis can result from several causes, including the immune system and after ophthalmic surgery. One of the most common reasons for vision loss with uveitis is macular edema. TA has been used for many years as an intravitreal injection for the treatment of ocular diseases. Several case control studies have been reported showing the efficacy of TA in the treatment of intraocular inflammation and associated macular edema caused by Behcet’s disease, Vogt-Koyanagi-Harada syndrome, sympathetic ophthalmia and white dot syndromes. It has also been shown efficacious in cases of pars planitis and idiopathic posterior uveitis. Some authors have reported its use in postoperative cystoid macular edema. Many of the studies on the use of TA in controlling intraocular inflammation and concomitant macular edema showed its effect to be transient in many patients requiring reinjection. Complications can arise from intravitreal injection of TA including elevated intraocular pressure and cataract. Rarely, it can be associated with infectious and non-infectious endophthalmitis. TA may be useful as an adjuvant in the treatment of uveitis and its associated macular edema, especially in patients resistant or intolerant to standard treatment.Keywords: triamcinolone acetonide, Behcet’s disease, sympathetic ophthalmia, Vogt-Koyanagi-Harada syndrome, white dot syndromes, uveitis, cataract surgery, macular edema, endophthalmitis

  9. Comparative study of two silicone hydrogel contact lenses used as bandage contact lenses after photorefractive keratectomy

    OpenAIRE

    Hasan Razmjoo; Elham Abdi; Sayna Atashkadi; Akhlaghi M Reza; Peyman A Reza; Mojtaba Akbari

    2012-01-01

    Background: Silicon hydrogel bandage contact lenses are used to enhance epithelial healing, control surface-generated pain, and prevent epithelial erosions after refractive surgery. Considering the importance of faster reepithelialization in preventing complications of photorefractive keratectomy (PRK) and the fact that the features and specifications of these commercially-available lenses are different and their performance as a postoperative bandage lenses would be different also, the aim o...

  10. Sustained Neural Stem Cell-Based Intraocular Delivery of CNTF Attenuates Photoreceptor Loss in the nclf Mouse Model of Neuronal Ceroid Lipofuscinosis.

    Directory of Open Access Journals (Sweden)

    Wanda Jankowiak

    Full Text Available A sustained intraocular administration of neurotrophic factors is among the strategies aimed at establishing treatments for currently untreatable degenerative retinal disorders. In the present study we have analyzed the neuroprotective effects of a continuous neural stem (NS cell-based intraocular delivery of ciliary neurotrophic factor (CNTF on photoreceptor cells in the nclf mouse, an animal model of the neurodegenerative lysosomal storage disorder variant late infantile neuronal ceroid lipofuscinosis (vLINCL. To this aim, we genetically modified adherently cultivated NS cells with a polycistronic lentiviral vector encoding a secretable variant of CNTF together with a Venus reporter gene (CNTF-NS cells. NS cells for control experiments (control-NS cells were modified with a vector encoding the reporter gene tdTomato. Clonal CNTF-NS and control-NS cell lines were established using fluorescent activated cell sorting and intravitreally grafted into 14 days old nclf mice at the onset of retinal degeneration. The grafted cells preferentially differentiated into astrocytes that were attached to the posterior side of the lenses and the vitreal side of the retinas and stably expressed the transgenes for at least six weeks, the latest post-transplantation time point analyzed. Integration of donor cells into host retinas, ongoing proliferation of grafted cells or adverse effects of the donor cells on the morphology of the host eyes were not observed. Quantitative analyses of host retinas two, four and six weeks after cell transplantation revealed the presence of significantly more photoreceptor cells in eyes with grafted CNTF-NS cells than in eyes with grafted control-NS cells. This is the first demonstration that a continuous intraocular administration of a neurotrophic factor attenuates retinal degeneration in an animal model of neuronal ceroid lipofuscinosis.

  11. Intraocular nematode with diffuse unilateral subacute neuroretinitis: case report

    Directory of Open Access Journals (Sweden)

    Zakariah Sakinah

    2011-06-01

    Full Text Available Abstract Background Live intraocular nematode is a rare occurrence. Nematode can migrate actively within the eye, creating visual symptoms and damaging ocular tissue. Case presentation A 26-year old man presented with painless reduced vision of the left eye for one week duration. It was associated with floaters. Visual acuity on the left eye was hand movement. Anterior segment examination was normal with normal intra-ocular pressure. Fundus examination showed a live nematode lying subretinally at the macular area with macular oedema and multifocal chorioretinal lesions at peripheral retina. There was no vitritis, vasculitis or any retinal hemorrhage. Systemic examination revealed normal findings and laboratory studies only showed leucocytosis with normal eosinophil count and negative serum toxocara antibody. The diagnosis of introcular nematode with diffuse unilateral subacute neuroretinitis was made. He was treated with oral anti-helminths and a course of oral steroid at a reducing dose. The nematode had died evidenced by its immobility during the treatment and finally disintegrated, leaving macular oedema with mottling appearance and mild hyperpigmentation. Multifocal chorioretinal lesions had also resolved. However despite treatment his visual acuity during follow-up had remained poor. Conclusions Cases of intraocular nematode, though not commonly encountered, continue to present the ophthalmologist with the problem of diagnosis and management and hence poorer prognosis to the patient.

  12. Sunlight exposure as risk factor for intraocular malignant melanoma

    International Nuclear Information System (INIS)

    In a case-control study, the authors compared 444 patients with intraocular malignant melanoma with matched controls to evaluate the role of exposure to ultraviolet radiation and other risk factors in the pathogenesis of this tumor. Persons born in the southern United States had a relative risk of 2.7 (95 per cent confidence interval, 1.3 to 5.9) as compared with those born in the North. Subjects with brown eyes were protected as compared with those with blue eyes (relative risk, 0.6; 95 per cent confidence interval, 0.4 to 0.8), but complexion and hair color were not important risk factors. Patients with intraocular malignant melanoma were also more likely to have spent time outdoors in their gardens, to have sunbathed, and to have used sunlamps. Rarely wearing hats, visors, or sunglasses while in the sun was a risk factor for the disease (relative risk, 1.9; 95 per cent confidence interval, 1.6 to 2.2). These data suggest that sunlight exposure is an important risk factor for intraocular melanoma

  13. An unusual case of marble intraocular foreign body

    Directory of Open Access Journals (Sweden)

    Omoti Afekhide

    2008-01-01

    Full Text Available This report presents a case of marble intraocular foreign body that developed toxic complications during surgery. The patient is a 25 years old male who presented to the University of Benin Teaching Hospital with a history of trauma to the right eye while cutting marble. He was examined, had an ocular ultrasound scan and subsequently had an extracapsular cataract extraction. His visual acuity in the right eye was light perception. There was an entry point on the cornea, the lens was opaque, there was vitreous haemorrhage and the intraocular foreign body was localized in the posterior part of the posterior segment by ultrasound scan. He had extracapsular cataract extraction. During anterior capsulotomy, the cornea suddenly and rapidly became cloudy with a brownish tinge and the corneal epithelium started desquamating.Marble on its own may not be toxic but the other chemicals including cement, used in the processing of the marble were responsible for this delayed toxicity. Ultrasound scan is valuable in localisation of intraocular foreign bodies.

  14. Effects of Mirtogenol® on ocular blood flow and intraocular hypertension in asymptomatic subjects

    OpenAIRE

    Steigerwalt, Robert D; Gianni, Belcaro; Paolo, Morazzoni; Bombardelli, Ezio; Burki, Carolina; Schönlau, Frank

    2008-01-01

    Purpose The most important variable risk factor for developing glaucoma is intraocular hypertension. Timely lowering of high intraocular pressure (IOP) significantly lowers the likelihood of developing glaucoma. The aim of this study was to evaluate the effects of the food supplement Mirtogenol® (Mirtoselect® and Pycnogenol®) on IOP and ocular blood flow in a product evaluation study. Methods Thirty-eight asymptomatic subjects with intraocular hypertension were either given Mirtogenol® (20 su...

  15. Successful Removal of Large Intraocular Foreign Body by 25-Gauge Microincision Vitrectomy Surgery

    OpenAIRE

    Hiroshi Kunikata; Megumi Uematsu; Toru Nakazawa; Nobuo Fuse

    2011-01-01

    We describe a new technique for removing a large intraocular foreign body by 25-gauge microincision vitrectomy surgery (25G-MIVS). Noncomparative interventional case series were performed at a single centre. Two patients with a long smooth intraocular vitreal foreign body underwent phacoemulsification and aspiration, intraocular lens implantation, 25G-MIVS, and extraction of the foreign body. The foreign body was removed through a posterior capsulorhexis, anterior continuous curvilinear capsu...

  16. 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 by...... Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies, but it...... is based on well understood physics and unlike distance ladder methods there are no calibration issues. Moreover, it has an advantage over some of the leading methods (such as Type Ia SNe) in that it is a purely cosmological approach. In this thesis, the property of strong gravitational lensing...

  17. Doubling Strong Lensing as a Cosmological Probe

    CERN Document Server

    Linder, Eric V

    2016-01-01

    Strong gravitational lensing provides a geometric probe of cosmology in a unique manner through distance ratios involving the source and lens. This is well known for the time delay distance derived from measured delays between lightcurves of the images of variable sources such as quasars. Recently, double source plane lens systems involving two constant sources lensed by the same foreground lens have been proposed as another probe, involving a different ratio of distances measured from the image positions and fairly insensitive to the lens modeling. Here we demonstrate that these two different sets of strong lensing distance ratios have strong complementarity in cosmological leverage. Unlike other probes, the double source distance ratio is actually more sensitive to the dark energy equation of state parameters $w_0$ and $w_a$ than to the matter density $\\Omega_m$, for low redshift lenses. Adding double source distance ratio measurements can improve the dark energy figure of merit by 40% for a sample of fewer...

  18. The Sloan Nearby Cluster Weak Lensing Survey

    CERN Document Server

    Kubo, Jeffrey M; Hardin, Frances Mei; Kubik, Donna; Lawhorn, Kelsey; Lin, Huan; Nicklaus, Liana; Nelson, Dylan; Reis, Ribamar R R; Seo, Hee-Jong; Soares-Santos, Marcelle; Stebbins, Albert; Yunker, Tony

    2009-01-01

    We describe and present initial results of a weak lensing survey of nearby ($\\rm{z}\\lesssim0.1$) galaxy clusters in the Sloan Digital Sky Survey (SDSS). In this first study, galaxy clusters are selected from the SDSS spectroscopic galaxy cluster catalogs of \\citet{miller05} and \\citet{berlind06}. We report a total of seven individual low redshift cluster weak lensing measurements which include: A2048, A1767, A2244, A1066, A2199, and two clusters specifically identified with the C4 algorithm. Our program of weak lensing of nearby galaxy clusters in the SDSS will eventually reach $\\sim 200$ clusters, making it the largest weak lensing survey of individual galaxy clusters to date.

  19. Intrinsic Galaxy Alignments and Weak Gravitational Lensing

    CERN Document Server

    Heavens, A F

    2001-01-01

    Gravitational lensing causes background galaxy images to become aligned, and the statistical characteristics of the image alignments can then be used to constrain the power spectrum of mass fluctuations. Analyses of gravitational lensing assume that intrinsic galaxy alignments are negligible, but if this assumption does not hold, then the interpretation of image alignments will be in error. As gravitational lensing experiments become more ambitious and seek very low-level alignments arising from lensing by large-scale structure, it becomes more important to estimate the level of intrinsic alignment in the galaxy population. In this article, I review the cluster of independent theoretical studies of this issue, as well as the current observational status. Theoretically, the calculation of intrinsic alignments is by no means straightforward, but some consensus has emerged from the existing works, despite each making very different assumptions. This consensus is that a) intrinsic alignments are a small but non-n...

  20. Time delays in cosmology with gravitational lenses

    Science.gov (United States)

    Falco, E. E.

    Gravitational lenses yield a very high rate of return on observational investment. Given their scarcity, their impact on our knowledge of the universe is very significant. In the weak-field limit, lensing studies are based on well-established physics and thus offer a straightforward approach to pursue many currently pressing problems of astrophysics and cosmology. Examples of these are the significance of dark matter and the density, age and size of the universe. I present recent developments in cosmological applications of gravitational lenses, focusing on estimates of the Hubble constant using strong lensing of quasars. I describe our recent measurements of time delays for the images of SDSSJ1004+4112, and discuss prospects for the future utilizing synoptic telescopes, planned and under construction.

  1. Current indications for scleral contact lenses.

    Science.gov (United States)

    Foss, A J; Trodd, T C; Dart, J K

    1994-04-01

    Scleral contact lenses have been largely superseded by corneal contact lenses, but they still retain a role as a treatment of choice for a small group of patients who have tried other types of contact lens wear without success and who are not good candidates for surgery. We performed a cross sectional survey of 44 patients attending clinics at Moorfields Eye Hospital who were successful long-term scleral contact lens wearers and reviewed their indications. Twenty-one patients had been fit to improve visual acuity, 20 for therapeutic indications, and three for cosmetic reasons. Scleral lenses were most useful were with patients with ocular surface disorders, such as Stevens-Johnson syndrome, and for visual rehabilitation of patients with grossly irregular corneal topography. All patients were benefiting from scleral contact lens wear, and none had serious complications as a result of the scleral lens wear. We conclude that all ophthalmic departments should have access to these lenses. PMID:8044976

  2. Hydrophilic synthetic polymers for soft contact lenses

    International Nuclear Information System (INIS)

    A process for preparing a hydrophilic synthetic polymer usable as soft contact lenses is provided. The process comprises copolymerizing 20 parts (by wt.) of 2-hydroxyethyl methacrylate with 0.5 to 3 parts of vinyl acetate and 0.1 to 1 part of a cross-linking monomer (A). The polymerization is carried out either catalytically or by radiation. The resulting copolymer is mechanically fabricated and then swollen with water to give soft contact lenses. The lenses are stable both dynamically and optically, do not injure the cornea, and are capable of correcting regular astigmatism. In one example, 20 parts of 2-hydroxyethyl methacrylate were copolymerized in a mold with 1 part of vinyl acetate and 0.5 part of divinylbenzene (A) by irradiation with Co 60 radiation (1 x107 r) and then thermally treated. A transparent hydrophilic polymer usable as soft contact lenses was obtained. (Kaichi, S.)

  3. Cosmological Information from Lensed CMB Power Spectra

    CERN Document Server

    Smith, K M; Kaplinghat, M; Smith, Kendrick M.; Hu, Wayne; Kaplinghat, Manoj

    2006-01-01

    Gravitational lensing distorts the cosmic microwave background (CMB) temperature and polarization fields and encodes valuable information on distances and growth rates at intermediate redshifts into the lensed power spectra. The non-Gaussian bandpower covariance induced by the lenses is negligible to l=2000 for all but the B polarization field where it increases the net variance by up to a factor of 10 and favors an observing strategy with 3 times more area than if it were Gaussian. To quantify the cosmological information, we introduce two lensing observables, characterizing nearly all of the information, which simplify the study of non-Gaussian impact, parameter degeneracies, dark energy models, and complementarity with other cosmological probes. Information on the intermediate redshift parameters rapidly becomes limited by constraints on the cold dark matter density and initial amplitude of fluctuations as observations improve. Extraction of this information requires deep polarization measurements on only ...

  4. A capacitor-based sensor and a contact lens sensing system for intraocular pressure monitoring

    Science.gov (United States)

    Chiou, Jin-Chern; Huang, Yu-Chieh; Yeh, Guan-Ting

    2016-01-01

    This study proposes a capacitor-based sensor on a soft contact lens for the measurement of intraocular pressure (IOP). The sensor was designed and fabricated via microelectromechanical system fabrication technologies. The soft contact lens is designed to be worn on a cornea such that the curvature of the contact lens corresponds substantially to that of the cornea. In addition, the contact lens was fabricated via a cast-molding method using poly-2-hydroxyethyl methacrylate to achieve a lens with high oxygen permeability, which can be worn comfortably for a long time. An IOP sensor prototype was implemented, which exhibited 1.2239 pF mmHg-1 (13,171 ppm mmHg-1) sensitivity during measurements of an artificial anterior chamber at pressures between 18 and 30 mmHg. The results indicate that the developed capacitor-based IOP sensor exhibited high stability and reproducibility in a series of measurements performed under various pressures. The capacitance of the proposed IOP sensor can successfully be converted into a digital value via a capacitor-to-digital converter and be transmitted via a commercial wireless telemetry system in this study.

  5. The Origin of Weak Lensing Convergence Peaks

    OpenAIRE

    Liu, Jia; Haiman, Zoltan

    2016-01-01

    Weak lensing convergence peaks are a promising tool to probe nonlinear structure evolution at late times, providing additional cosmological information beyond second-order statistics. Previous theoretical and observational studies have shown that the cosmological constraints on $\\Omega_m$ and $\\sigma_8$ are improved by a factor of up to ~ 2 when peak counts and second-order statistics are combined, compared to using the latter alone. We study the origin of lensing peaks using observational da...

  6. The focusing properties of solenoid lenses

    International Nuclear Information System (INIS)

    Solenoids show inevitability their spherical aberration, which increases beam effective emittance. In this work the author make efforts to improve field quality in different ways. Calculations tell that increasing gap size of pole pieces or taping magnet poles can obviously reduce coefficient of spherical aberration. The equivalent parameters of solenoid lenses are calculated according to axial magnetic field pattern of lenses; they only relate to its geometry, independent of its magnetic field inductivity strength

  7. Weak lensing, dark matter and dark energy

    OpenAIRE

    Huterer, Dragan

    2010-01-01

    Weak gravitational lensing is rapidly becoming one of the principal probes of dark matter and dark energy in the universe. In this brief review we outline how weak lensing helps determine the structure of dark matter halos, measure the expansion rate of the universe, and distinguish between modified gravity and dark energy explanations for the acceleration of the universe. We also discuss requirements on the control of systematic errors so that the systematics do not appreciably degrade the p...

  8. Chromagen lenses and abnormal colour perception

    OpenAIRE

    O. Matthew Oriowo; Abdullah Z. Alotaibi

    2011-01-01

    Background: The Chromagen lens system comprises of tinted spectacle or contact lenses, each with a specific colour wavelength filter which controls the spectra of the light entering the eye. This study investigated whether spectacle-mounted Chromagen lenses would enhance colour perception in individuals with abnormal colour vision.Methods: The Ishihara colour test was used to test for colour vision deficiency (CVD) and also to evaluate the effect of the Chromagen spectacle lens on colour perc...

  9. Lensing Time Delays and Cosmological Complementarity

    OpenAIRE

    Linder, Eric V.

    2011-01-01

    Time delays in strong gravitational lensing systems possess significant complementarity with distance measurements to determine the dark energy equation of state, as well as the matter density and Hubble constant. Time delays are most useful when observations permit detailed lens modeling and variability studies, requiring high resolution imaging, long time monitoring, and rapid cadence. We quantify the constraints possible between a sample of 150 such time delay lenses and a near term supern...

  10. Keeping an eye on dialysis: the association of hemodialysis with intraocular hypertension.

    Science.gov (United States)

    William, Jeffrey H; Gilbert, Aubrey L; Rosas, Sylvia E

    2015-11-01

    Intraocular hypertension is common during hemodialysis. Dialysis disequilibrium syndrome and intraocular hypertension occur via similar pathophysiologic mechanisms. These mechanisms may contribute to the development of glaucoma and cataracts in a patient population already at high risk for ocular abnormalities, given the common risk factors for chronic kidney disease and impaired aqueous humor outflow. We describe a patient with complicated diabetes mellitus, end-stage renal disease, and recent cataract surgery who developed severe intraocular hypertension during hemodialysis. We recommend increased awareness of the symptoms of intraocular hypertension and subsequent ophthalmologic surveillance in order to prevent long-term visual complications. PMID:26042412

  11. A method to calculate Fresnel lenses

    International Nuclear Information System (INIS)

    In solar engineering, in contrast to image optics, Fresnel lenses are intended for securing the required concentrations of solar radiation and its distribution over a receiver's surface. It is also important to secure a high use coefficient of the concentrated flux. In particular, this defines the features of calculation of Fresnel lenses: it is necessary to take into account inaccuracies in fabrication of Fresnel lenses and solar radiation redistribution by means of selecting the respective parameters of Fresnel lens belts. In the present work, we examine the procedure for the calculating geometrical parameters of Fresnel lenses on a flat base by considering the mentioned requirements. A corresponding software for calculating the geometrical parameters and concentrating characteristics of the Fresnel lenses is developed, and examples of calculation are given. For a constant refractive index of Fresnel lens material, it is shown that the Fresnel lens can secure a concentration of about 1000, but in this case the optical efficiency of the Fresnel lens will not be higher than 70%. The procedure that has been developed may be the basic one for determining the parameters and concentrating characteristics of Fresnel lenses by considering refractive index variance. (author)

  12. Statistical challenges in weak lensing cosmology

    CERN Document Server

    Takada, Masahiro

    2014-01-01

    Cosmological weak lensing is the powerful probe of cosmology. Here we address one of the most fundamental, statistical questions inherent in weak lensing cosmology: whether or not we can recover the initial Gaussian information content of large-scale structure by combining the weak lensing observables, here focused on the weak lensing power spectrum and bispectrum. To address this question we fully take into account correlations between the power spectra of different multipoles and the bispectra of different triangle configurations, measured from a finite area survey. In particular we show that super-survey modes whose length scale is larger than or comparable with the survey size cause significant sample variance in the weak lensing correlations via the mode-coupling with sub-survey modes due to nonlinear gravitational clustering -- the so-called super-sample variance. In this paper we discuss the origin of the super-sample variance and then study the information content inherent in the weak lensing correlat...

  13. Cosmological test using strong gravitational lensing systems

    CERN Document Server

    Yuan, C C

    2015-01-01

    As one of the probes of universe, strong gravitational lensing systems allow us to compare different cosmological models and constrain vital cosmological parameters. This purpose can be reached from the dynamic and geometry properties of strong gravitational lensing systems, for instance, time-delay $\\Delta\\tau$ of images, the velocity dispersion $\\sigma$ of the lensing galaxies and the combination of these two effects, $\\Delta\\tau/\\sigma^2$. In this paper, in order to carry out one-on-one comparisons between $\\Lambda$CDM universe and $R_h=ct$ universe, we use a sample containing 36 strong lensing systems with the measurement of velocity dispersion from the SLACS and LSD survey. Concerning the time-delay effect, 12 two-image lensing systems with $\\Delta\\tau$ are also used. In addition, Monte Carlo (MC) simulations are used to compare the efficiency of the three methods as mentioned above. From simulations, we estimate the number of lenses required to rule out one model at the $99.7\\%$ confidence level. Compar...

  14. Cosmological test using strong gravitational lensing systems

    Science.gov (United States)

    Yuan, C. C.; Wang, F. Y.

    2015-09-01

    As one of the probes of universe, strong gravitational lensing systems allow us to compare different cosmological models and constrain vital cosmological parameters. This purpose can be reached from the dynamic and geometry properties of strong gravitational lensing systems, for instance, time-delay Δτ of images, the velocity dispersion σ of the lensing galaxies and the combination of these two effects, Δτ/σ2. In this paper, in order to carry out one-on-one comparisons between ΛCDM universe and Rh = ct universe, we use a sample containing 36 strong lensing systems with the measurement of velocity dispersion from the Sloan Lens Advanced Camera for Surveys (SLACS) and Lens Structure and Dynamic survey (LSD) survey. Concerning the time-delay effect, 12 two-image lensing systems with Δτ are also used. In addition, Monte Carlo simulations are used to compare the efficiency of the three methods as mentioned above. From simulations, we estimate the number of lenses required to rule out one model at the 99.7 per cent confidence level. Comparing with constraints from Δτ and the velocity dispersion σ, we find that using Δτ/σ2 can improve the discrimination between cosmological models. Despite the independence tests of these methods reveal a correlation between Δτ/σ2 and σ, Δτ/σ2 could be considered as an improved method of σ if more data samples are available.

  15. Strong gravitational lensing with the SKA

    CERN Document Server

    McKean, J P; Vegetti, S; Rybak, M; Serjeant, S; Koopmans, L V E; Metcalf, R B; Fassnacht, C D; Marshall, P J; Pandey-Pommier, M

    2015-01-01

    Strong gravitational lenses provide an important tool to measure masses in the distant Universe, thus testing models for galaxy formation and dark matter; to investigate structure at the Epoch of Reionization; and to measure the Hubble constant and possibly w as a function of redshift. However, the limiting factor in all of these studies has been the currently small samples of known gravitational lenses (~10^2). The era of the SKA will transform our understanding of the Universe with gravitational lensing, particularly at radio wavelengths where the number of known gravitational lenses will increase to ~10^5. Here we discuss the technical requirements, expected outcomes and main scientific goals of a survey for strong gravitational lensing with the SKA. We find that an all-sky (3pi sr) survey carried out with the SKA1-MID array at an angular resolution of 0.25-0.5 arcsec and to a depth of 3 microJy / beam is required for studies of galaxy formation and cosmology with gravitational lensing. In addition, the ca...

  16. Ophthalmic glucose monitoring using disposable contact lenses.

    Science.gov (United States)

    Geddes, Chris

    2004-01-01

    We have developed a range of disposable and colorless tear glucose sensing contact lenses, using off-the-shelf lenses embedded with new water soluble, highly fluorescent and glucose sensitive boronic acid containing fluorophores. The new lenses are readily able to track tear glucose levels and therefore blood glucose levels, which are ideally suited for potential use by diabetics. The fluorescence responses from the lenses can be monitored using simple excitation and emission detection devices. The novelty of our approach is two fold. Firstly, the notion of sensing extremely low glucose concentrations in tears, which track blood levels, by our contact lens approach, and secondly, the unique compatibility of our new glucose signaling probes with the internal mildly acidic contact lens environment. The new lenses are therefore ideal for the noninvasive and continuous monitoring of tear glucose, with a 15 minute response time, and a measured shelf life in excess of 3 months. In this invited article, we show that fluorescence based signaling using plastic disposable lenses, which have already been industrially optimized with regard to vision correction and oxygen / analyte permeability etc, may a notable alternative to invasive and random finger pricking, the most widely used glucose monitoring technology by diabetics. PMID:17271473

  17. Three chamber negative ion source

    International Nuclear Information System (INIS)

    A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential

  18. Scintillations in ionization chambers

    International Nuclear Information System (INIS)

    High purity Ar and mixtures of Ar with 1% CH4, 3% CH4, CO2 and N2, respectively, have been applied for fission fragment detection in a gridded ionization chamber. Gas scintillation has been observed simultaneously with a photomultiplier VALVO-XP 2041. Whereas all mixtures work equally well as an ionization gas, only Ar + 3% N2 shows a primary scintillation yield sufficient for fas timing. (orig.)

  19. Double chambered right ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1983-12-15

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure.

  20. Optimal Weak Lensing Skewness Measurements

    CERN Document Server

    Zhang, T J; Zhang, P; Dubinski, J; Zhang, Tong-Jie; Pen, Ue-Li; Zhang, Pengjie; Dubinski, John

    2003-01-01

    Weak lensing measurements are entering a precision era to statistically map the distribution of matter in the universe. The most common measurement has been of the variance of the projected surface density of matter, which corresponds to the induced correlation in alignments of background galaxies. This measurement of the fluctuations is insensitive to the total mass content, like using waves on the ocean to measure its depths. But when the depth is shallow as happens near a beach, waves become skewed. Similarly, a measurement of skewness in the projected matter distribution directly measures the total matter content of the universe. While skewness has already been convincingly detected, its constraint on cosmology is still weak. We address optimal analyses for the CFHT Legacy Survey in the presence of noise. We show that a compensated Gaussian filter with a width of 2.5 arc minutes optimizes the cosmological constraint, yielding $\\Delta \\Omega_m/\\Omega_m\\sim 10%$. This is significantly better than other filt...