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Sample records for lens vitreous body

  1. Effects of lens extirpation with anterior vitrectomy on vitreous three-dimensional mesh structure

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    Yan Zhao

    2017-06-01

    Full Text Available AIM: To investigate the changes in vitreous gel structure after lens extirpation combined with anterior vitrectomy in rabbit eyes. METHODS: Twenty-eight chinchilla rabbits were divided into three groups. The control group (Group I included 16 eyes from eight rabbits who did not receive any treatment. Group II included 20 eyes from 10 rabbits that underwent lens aspiration only. Group III included 20 eyes from 10 rabbits that underwent lens aspiration combined with posterior capsulotomy and anterior vitrectomy. Eyes were harvested on the 30th and 60th day postoperatively, respectively. Changes in vitreous gel stretch length due to gravity and the rate of vitreous liquefaction were observed. The collagen content in the vitreous body was examined using the L-hydroxyproline test. Electronic microscopic images were obtained from each eyeball. RESULTS: On both the 30th and 60th day postoperatively, the vitreous gel length of group III was significantly shorter than group I and group II (P<0.05, while the rate of liquefaction of the vitreous body in group III was significantly higher than group I and group II (P<0.05. The collagen content in group III was also higher than that in group I and group II (P<0.05. CONCLUSION: Loss of vitreous gel mass is more likely to occur in the eyes of rabbits receiving anterior vitrectomy. Lensectomy combined with anterior vitrectomy may damage the stable three-dimensional mesh structure of collagen, which could aggravate vitreous gel liquefaction.

  2. Sectioning a luxated intraocular lens inside the vitreous cavity.

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    Vilaplana, Daniel; Pazos, Marta

    2013-07-01

    We describe a new technique for sectioning an intraocular lens (IOL) inside the vitreous cavity. The IOL had a broken haptic and was accidentally luxated after a complicated cataract surgery with posterior capsule rupture. The primary indication to cut the IOL in half inside the vitreous cavity is to preserve the anterior capsule integrity, especially in a small-sized capsulotomy, allowing subsequent implantation of a new IOL in the sulcus with the optical zone captured in the capsulorhexis. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Vascular remnants in the rabbit vitreous body. I. Morphological characteristics and relationship to vitreous embryonic development

    NARCIS (Netherlands)

    Los, LI; Van Luyn, MJA; Nieuwenhuis, P

    Using light and transmission electron microscopy, we observed novel structures in the rabbit vitreous body. They were found in 18 out of 27 eyes from rabbits 0.5-36 months of age. These structures are scattered throughout the entire vitreous matrix. By light and transmission electron microscopy,

  4. Vitreous Humor Changes Expression of Iron-Handling Proteins in Lens Epithelial Cells

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    Goralska, Malgorzata; Fleisher, Lloyd N.; McGahan, M. Christine

    2017-01-01

    Purpose In humans, vitrectomy is associated with development of nuclear cataracts. Iron catalyzes free radical formation causing oxidative damage, which is implicated in cataract formation. This study was designed to determine if vitreous humor, which can initiate differentiation of lens epithelial cells, would have an effect on iron-handling proteins. Methods Cultured canine lens epithelial cells were treated with collected canine vitreous humor. Lysates of treated and control cells were separated by SDS-PAGE. Ferritin H- and L-chains, transferrin receptor 1, and aquaporin 0 were immunodetected and quantitated with specific antibodies. Morphologic changes in treated cells were assessed. Results Treatment of lens epithelial cells with a 33% (vol/vol) solution of vitreous humor changed the morphology of lens cells and induced expression of aquaporin 0, a marker of fiber cell differentiation that was undetectable in control cells. Treatment did not modify the size of iron-handling proteins but significantly increased content of ferritin from 2.9- to 8.8-fold over control and decreased levels of transferrin receptor by 37% to 59%. Conclusions Vitreous humor may significantly limit iron uptake by transferrin/transferrin receptor pathway, and by increasing ferritin levels could profoundly increase the iron-storage capacity of ferritin in lens cells. Vitreous humor may play a significant protective role against iron-catalyzed oxidative damage of lens epithelial cells and therefore in the formation of cataracts. PMID:28245299

  5. Intra-ocular lens implantation after vitreous loss.

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    Shah N

    1991-10-01

    Full Text Available Vitreous loss is a dreaded complication of cataract surgery, especially so with IOL implant which then may have to be abandoned. Thirty three cases of IOL implants, either anterior chamber or posterior chamber, after vitreous loss done in the past 3 years were studied. Of these, 18 (55% had a final visual acuity of 6/18 or better and none was worse than 6/60. The postoperative complications and findings and a review of literature are discussed.

  6. COMPARATIVE ANATOMY OF THE VITREOUS BODY IN RHESUS-MONKEYS AND MAN

    NARCIS (Netherlands)

    WORST, JGF; LOS, LI

    1992-01-01

    In the isolated unfixed vitreous body a structural organization can be visualized by slitlamp microscopy or by an ink-injection technique. We discuss the observations on human and rhesus monkey (Macaca mulatta) vitreous bodies using the ink-injection technique. Advantages and disadvantages of this

  7. [Buffering capacity of the vitreous body in aggressive posterior retinopathy of prematurity].

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    Amkhanitskaia, L I; Sidorenko, E I; Nikolaeva, G V; Kuznetsova, Iu D

    2014-01-01

    To investigate the role of vitreous body changes in the pathogenesis of aggressive posterior retinopathy of prematurity. The study included 60 children with stage 4-5 retinopathy of prematurity demonstrating either classical or aggressive posterior form of progression. In all cases vitreous samples for laboratory testing were taken during surgery. The study showed that aggressive posterior retinopathy of prematurity is associated with more significant metabolic changes in comparison with classical form of the disease. The degree of biochemical imbalance of the vitreous appeared directly related to the stage of the disease, which was determined by the type and extent of retinal detachment. Volcano-shaped retinal detachment with intensive exudation within the posterior eye segment is considered the most severe variant of aggressive posterior retinopathy of prematurity. Aggressive posterior retinopathy of prematurity is characterized by substantial disturbance of metabolism of the vitreous body, which contributes to exudation and proliferation, thus aggravating the course of the disease and worsening the prognosis.

  8. Supracapsular glued intraocular lens in progressive subluxated cataracts: Technique to retain an intact vitreous face.

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    Jacob, Soosan; Narasimhan, Smita; Agarwal, Amar; Mazzotta, Cosimo; Rechichi, Miguel; Agarwal, Athiya

    2017-03-01

    We describe a technique to prevent late intraocular lens (IOL) subluxation and dislocation that can be associated with progressive zonulopathy. Supracapsular glued IOL fixation is done to retain an intact anterior hyaloid face and avoid vitreous disturbance while providing stable long-term IOL fixation. Phacoemulsification is followed by glued IOL implantation above intact anterior and posterior capsules. Sclerotomies are created ab interno in a supracapsular plane under diametrically opposite lamellar scleral flaps without entering the vitreous cavity. Haptics are externalized in the supracapsular plane and tucked into intrascleral tunnels. Intraoperative or postoperative posterior capsulorhexis or capsulotomy and anterior capsule relaxing cuts can prevent capsule phimosis. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  9. Stability of endogenous GHB in vitreous humor vs peripheral blood in dead bodies.

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    Busardò, Francesco Paolo; Mannocchi, Giulio; Giorgetti, Raffaele; Pellegrini, Manuela; Baglio, Giovanni; Zaami, Simona; Marinelli, Enrico; Pichini, Simona

    2017-05-01

    For the first time, the stability of GHB was tested in post-mortem peripheral blood and vitreous humor samples, collected from 22 dead bodies at two different times: at the external body examination at the place of death and then during autopsy. An ad hoc method for the detection and quantification of GHB in vitreous humor by gas chromatography coupled to mass spectrometry (GC-MS) was developed and validated, with a good linearity between 0.1 and 50μg/mL (r 2 =0.991) and a precision and accuracy always better than 10% and an analytical recovery higher than 90%. The geometric mean of GHB concentration in the 22 peripheral blood samples at t 0 was: 3.6μg/mL (95% CI: 2.3-5.9μg/mL) and at t 1 it was 7.4μg/mL (95% CI: 5.0-10.9μg/mL); that of GHB in the 22 vitreous humor at t 0 was: 2.5μg/mL (95% CI: 1.5-4.1μg/mL) and at t 1 it was 3.0μg/mL (95% CI: 1.9-4.8μg/mL). There was no significant difference between the GHB concentrations in vitreous humor and peripheral blood at t 0 in all the samples (p>0.10). Conversely at t 1 , the increase of GHB in the peripheral blood was significantly increased by a 102% (range: 86-120%) (phumor only a slight increase by 19% was observed (range: 16-21%) (p>0.05 vs t 0 ). Finally at t 1 , GHB values in the two matrices were statistically different, being that of peripheral blood higher (phumor as a more stable alternative matrix in comparison to peripheral blood for the post-mortem determination of endogenous GHB. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Vitreous substitutes:challenges and directions

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    Qian-Ying Gao

    2015-06-01

    Full Text Available Thenatural vitreous body has a fine structure and complex functions. The imitation of the natural vitreous body by vitreous substitutes is a challenging work for both researchers and ophthalmologists. Gases, silicone oil, heavy silicone oil and hydrogels, particularly the former two vitreous substitutes are clinically widely used with certain complications. Those, however, are not real artificial vitreous due to lack of structure and function like the natural vitreous body. This article reviews the situations, challenges, and future directions in the development of vitreous substitutes, particularly the experimental and clinical use of a new artificial foldable capsular vitreous body .

  11. Characterization of the vitreous body of the human eye using a cyanine dye as a spectral and fluorescent probe

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    Panova, Ina G.; Tatikolov, Alexander S.

    2009-02-01

    We used one of cyanine dyes as a spectral and fluorescent probe in the study of the composition of the extracellular matrix of the human eye (its vitreous body). Owing to the unique ability of the dye to bind to collagens and human serum albumin, we revealed the simultaneous presence of both types of biomacromolecules in the vitreous body. The formation of the dye complex with human serum albumin leads to appearance of a long-wavelength absorption band (~612 nm) and a steep rise of fluorescence, whereas in the presence of collagens the dye forms J-aggregates with a longer-wavelength absorption band (640-660 nm) and moderate fluorescence. In this work we studied the composition of the human fetus vitreous body and its dynamics from 9 to 31 gestation weeks. On the basis of the data obtained by this method, we may assume that albumin, being a carrier protein, probably provides the vitreous body and surrounding tissues with necessary growth factors, hormones, lipids, vitamins, and some other biomolecules. The data show that the dye is promising not only for study of albumin functions in eye development, but also for characterization of some eye diseases and for analysis of other extracellular media.

  12. [Structure of the vitreous body over areas with lattice degeneration of the retina (author's transl)].

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    Slezak, H

    1975-12-04

    The clinical examination of the vitreous in the extreme fundus periphery is difficult; therefore only very little was known up to now about the relations of the posterior limiting membrane of the vitreous and the preretinal tract to retinal lattice degenerations arranged parallel to the ora serrata in several rows. There will be reports of new findings gained by depression biomicroscopy.

  13. Complicações da luxação do cristalino para a cavidade vítrea Complications of lens displacement into the vitreous cavity

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    Jacó Lavinsky

    2002-08-01

    Full Text Available Objetivo: Avaliar as complicações pré e pós-vitrectomia, sua correlação com o tempo de permanência do núcleo no vítreo e a acuidade visual final, bem como as complicações a longo prazo. Métodos: Estudo retrospectivo de 12 pacientes que apresentavam fragmentos do cristalino no vítreo pós-facectomia, submetidos a vitrectomia no Serviço de Oftalmologia do Hospital de Clínicas de Porto Alegre (HCPA entre novembro de 1994 e junho de 2000. Resultados: Após a queda do núcleo no vítreo, 5 pacientes apresentaram edema corneano, 3 uveíte, 8 glaucoma, 1 descolamento de retina e todos tiveram redução da acuidade visual. Submetidos à vitrectomia, no pós-operatório imediato 2 apresentavam hifema, 6 glaucoma, 2 descolamento de retina, 1 phthisis bulbi, 1 edema macular cistóide, 2 perfluorocarbono na câmara anterior e 7 edema corneano. No pós-operatório tardio, a maioria das complicações se resolveram (média de 6 meses. O tempo de permanência do núcleo luxado foi menor que 15 dias para 3 pacientes e maior que 15 dias para 9 pacientes. Conclusão: Os resultados sugerem que os fragmentos do cristalino retidos na cavidade vítrea devem ser removidos prontamente para impedir a resposta inflamatória, melhorando, assim, o prognóstico visual.Purpose: To evaluate the complications before and after vitrectomy, their correlation with the time the lens remained in the vitreous cavity, and final visual acuity. The long-term complications were also evaluated. Methods: Retrospective study of 12 patients who had lens material in the vitreous after cataract surgery. The patients underwent vitreous surgery from November 1994 to June 2000 at the Ophthalmology Service of the Hospital de Clínicas de Porto Alegre (HCPA. Results: After the displacement of the nucleus into the vitreous cavity, 5 patients had corneal edema, 3 had uveitis, 8 glaucoma, 1 retinal detachment, and all patients had reduced visual acuity. After vitrectomy, 2 patients had

  14. Organization of the rabbit vitreous body : Lamellae, Cloquet's channel and a novel structure, the 'alae canalis Cloqueti'

    NARCIS (Netherlands)

    Los, LI; van Luyn, MJA; Nieuwenhuis, P

    Even though the rabbit is a frequently used animal model for studies on Vitreous function and pathobiology, data on the structural organization of the rabbit Vitreous are scarce. The aim of the present study is to give a detailed description of rabbit vitreous structure in order to provide a basis

  15. Vitreous cinematography in the study of vitreoretinal diseases.

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    Trempe, C L; Takahashi, M; Freeman, H M

    1981-07-01

    A new technique of vitreous cinematography involves scanning of the vitreous cavity using optical sections to provide objective, reproducible information on the dynamics of the posterior vitreous and vitreoretinal relationships. Using a newly developed preset lens (El Bayadi-Kajiura lens), this technique makes it possible to document an entire optical section of the posterior vitreous. This is done by mechanically displacing the vitreous so that maximum reflectivity can be obtained from the vitreous gel. This article describes the technique and presents clinical examples documenting complete and incomplete vitreous detachment in normal eyes, Cloquet's canal associated with an optic disc pit, vitreous traction associated with a lamellar hole in an area of preretinal macular fibrosis, and vitreous traction at the anterior flap of a retinal break.

  16. The Relationship of Brimonidine Concentration in Vitreous Body to the Free Concentration in Retina/Choroid Following Topical Administration in Pigmented Rabbits.

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    Shinno, Keisuke; Kurokawa, Kazuya; Kozai, Seiko; Kawamura, Akio; Inada, Katsuhiro; Tokushige, Hideki

    2017-05-01

    Several studies showed that repeated topical administration of brimonidine tartrate ophthalmic solution reached the human vitreous concentration above 2 nM, which is the concentration necessary to activate the α 2 -adrenergic receptor. The purpose of this study was to elucidate the relationship of the brimonidine concentration in the vitreous body to the free concentration in the retina/choroid which is the target site of brimonidine on neuroprotective effect after topical administration. Brimonidine concentrations in the eye tissues of pigmented rabbits were determined following single ocular administration of 0.1% brimonidine tartrate ophthalmic solution at pH 7.3. Binding affinity of brimonidine to melanin and melanin content in the retina/choroid of pigmented rabbits was also examined. The concentration of free brimonidine which did not bind to melanin in the retina/choroid was calculated using the binding parameters to melanin. Topically applied brimonidine rapidly distributed to intraocular tissues. The elimination rate from melanin-containing tissues such as the iris/ciliary body and retina/choroid was slower than the aqueous humor and vitreous body in pigmented rabbits. In both the anterior and posterior retina/choroid, the free brimonidine concentrations were over 100-fold lower than the total concentrations. The concentrations in the vitreous body closely matched to the free concentrations in the posterior retina/choroid. Simulated free concentrations in the posterior retina/choroid were gradually increased when 0.1% solution was instilled twice daily. The present data indicated that the brimonidine concentration in the vitreous body was comparable to the free concentration in the posterior retina/choroid. This suggests that the vitreous concentration can be a surrogate indicator of the free brimonidine concentration in the posterior retina/choroid. From the present findings, it is expected that multiple instillation of brimonidine tartrate ophthalmic

  17. Whole vitreous humor dissection for vitreodynamic analysis.

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    Murali, Karthik; Kashani, Amir H; Humayun, Mark S

    2015-05-24

    The authors propose an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes. While previous studies have shown the results of such dissections, the detailed steps have not been described, precluding researchers outside the field from replicating their methods. Other studies harvest vitreous either through aspiration, which does not maintain the vitreous structure anatomy, or through partial dissection, which only isolates the vitreous core. The proposed method isolates the whole vitreous body, with the vitreous core and cortex intact, while maintaining vitreous anatomy and structural integrity. In this method, a full thickness scleral flap in an enucleated porcine eye is first created and through this, the choroid tissue can be separated from the sclera. The scleral flap is then expanded and the choroid is completely separated from the sclera. Finally the choroid-retina tissue is peeled off the vitreous to leave an isolated intact vitreous body. The proposed vitreous dissection technique can be used to study physical properties of the vitreous humor. In particular, this method has significance for experimental studies involving drug delivery, vitreo-retinal oxygen transport, and intraocular convection.

  18. A direct contact between astrocyte and vitreous body is possible in the rabbit eye due to discontinuities in the basement membrane of the retinal inner limiting membrane

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    A. Haddad

    2003-02-01

    Full Text Available Different from most mammalian species, the optic nerve of the rabbit eye is initially formed inside the retina where myelination of the axons of the ganglion cells starts and vascularization occurs. Astrocytes are confined to these regions. The aforementioned nerve fibers known as medullated nerve fibers form two bundles that may be identified with the naked eye. The blood vessels run on the inner surface of these nerve fiber bundles (epivascularization and, accordingly, the accompanying astrocytes lie mostly facing the vitreous body from which they are separated only by the inner limiting membrane of the retina. The arrangement of the astrocytes around blood vessels leads to the formation of structures known as glial tufts. Fragments (N = 3 or whole pieces (N = 3 of the medullated nerve fiber region of three-month-old male rabbits (Orictolagus cuniculus were fixed in glutaraldehyde followed by osmium tetroxide, and their thin sections were examined with a transmission electron microscope. Randomly located discontinuities (up to a few micrometers long of the basement membrane of the inner limiting membrane of the retina were observed in the glial tufts. As a consequence, a direct contact between the astrocyte plasma membrane and vitreous elements was demonstrated, making possible functional interactions such as macromolecular exchanges between this glial cell type and the components of the vitreous body.

  19. Intraocular lens dislocation after whole-body vibration.

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    Vela, José I; Andreu, David; Díaz-Cascajosa, Jesús; Buil, José A

    2010-10-01

    We present 2 cases of intraocular lens (IOL) dislocation that appeared shortly after the patients exercised on a vibration platform. The first patient was a 71-year-old woman who presented with lens subluxation in her right eye and a complete posterior IOL dislocation in her left eye. The second case was a 62-year-old woman who presented with unilateral IOL dislocation within the capsular bag in her right eye. Timing from IOL implantation to dislocation was approximately 6 years and 4 years, respectively. Pars plana vitrectomy with removal of the dislocated IOL was performed in both patients. Whole-body vibration training has become increasingly popular as a form of exercise training. It reportedly may provide benefits in physical function and in some diseases, especially in older people. However, evidence-based protocols ensuring safety and efficacy in this population are lacking. We discuss vibration as a cause of late IOL dislocation. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  20. Regional distribution of phospholipids in porcine vitreous humor.

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    Schnepf, Abigail; Yappert, Marta Cecilia; Borchman, Douglas

    2017-07-01

    This project explores the regional phospholipid distribution in porcine vitreous humor, retina, and lens. Matrix-assisted laser desorption mass spectrometry has been used previously to image lipids, proteins, and other metabolites in retinas and lenses. However, the regional composition of phospholipids in vitreous humors is not known. To address this issue, we have applied this mass spectral method to explore the regional phospholipid distribution in porcine vitreous humor both ex-situ and in-vitro. To establish the possible source(s) of phospholipids in the vitreous humor, compositional studies of the lens and retina were also pursued. Due to the overall low levels of phospholipids in vitreous humor, it was necessary to optimize the experimental approaches for ex-situ and in-vitro studies. The sensitivity observed in the spectra of methanol extracts from the lens and retina was higher than that for methanol:chloroform extracts, but the compositional trends were the same. A fourfold improvement in sensitivity was observed in the analysis of vitreous humor extracts obtained with the Bligh and Dyer protocol relative to the other two extraction methods. For ex-situ studies, the 'stamp method' with para-nitroaniline as the matrix was chosen. Throughout the vitreous humor, phosphatidylcholines were the most abundant phospholipids. In-vitro results showed higher relative levels of phospholipids compared to the 'stamp' method. However, more details in the regional phospholipid distribution were provided by the ex-situ approach. Both in-vitro and ex-situ results indicated higher levels of phospholipids in the posterior vitreous region, followed by the anterior and central regions. The posterior region contained more unsaturated species whereas more saturated phospholipids were detected in the anterior region. The observed trends suggest that the phospholipids detected in the posterior vitreous humor migrate from the retina and associated vasculature while those present in

  1. Eye rotation induced dynamics of a Newtonian fluid within the vitreous cavity: the effect of the chamber shape

    International Nuclear Information System (INIS)

    Stocchino, Alessandro; Repetto, Rodolfo; Cafferata, Chiara

    2007-01-01

    The dynamics of the vitreous body induced by eye rotations is studied experimentally. In particular, we consider the case in which the vitreous cavity is filled by a Newtonian fluid, either because the vitreous is liquefied or because it has been replaced, after vitrectomy, by a viscous fluid. We employ a rigid Perspex container which models, in a magnified scale, the vitreous cavity of the human eye. The shape of the cavity closely resembles that of the real vitreous chamber; in particular, the anterior part of the container is concave in order to model the presence of the eye lens. The container is filled with glycerol and is mounted on the shaft of a computer-controlled motor which rotates according to a periodic time law. PIV (particle image velocimetry) measurements are taken on the equatorial plane orthogonal to the axis of rotation. The experimental measurements show that the velocity field is strongly influenced by the deformed geometry of the domain. In particular, the formation of a vortex in the vicinity of the lens, which migrates in time towards the core of the domain, is invariably observed. The vortex path is tracked in time by means of a vortex identification technique and it is found that it is significantly influenced by the Womersley number of the flow. Particle trajectories are computed from the PIV measurements. Particles initially located at different positions on the equatorial horizontal plane (perpendicular to the axis of rotation) tend to concentrate in narrow regions adjacent to the lens, thus suggesting the existence, in such regions, of a vertical fluid ejection. Such a strong flow three-dimensionality, which is essentially induced by the irregular shape of the domain, may play a significant role in the mixing processes taking place inside the eye globe. The tangential stresses acting on the rigid boundary of the domain are also computed from the experimental measurements showing that regions subject to particularly intense stresses

  2. The effects of aging vitreous on contrast sensitivity function.

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    Garcia, Giancarlo A; Khoshnevis, Matin; Yee, Kenneth M P; Nguyen, Justin H; Nguyen-Cuu, Jeannie; Sadun, Alfredo A; Sebag, J

    2018-05-01

    Contrast sensitivity function (CSF) declines with age. When unassociated with cataracts, this is hypothesized to be due to macular ganglion cell complex (GCC) thinning. However, other studies found associations with increased vitreous echodensity and posterior vitreous detachment (PVD). We investigate the relationship between CSF, vitreous echodensity, PVD, and GCC thickness as related to age in the same subjects. Age, CSF (Weber index: %W), vitreous echodensity (quantitative ultrasonography [QUS]), lens status (phakia or pseudophakia), best-corrected visual acuity (BCVA), and GCC thickness (SD-OCT) were evaluated in 57 eyes of 57 subjects with (n = 32, mean age = 62 years) and without (n = 25, mean age = 44 years) PVD (P PVD (2.98 ± 0.31 %W) compared to no PVD (1.97 ± 0.24 %W; P PVD than those without (P PVD status, vitreous echodensity, and age were the only independent variables demonstrating significant effects on CSF. Lens status, BCVA, and GCC thickness did not demonstrate association with CSF. PVD, vitreous echodensity, and age are determinants of CSF. PVD and increased vitreous echodensity are each associated with diminished CSF, independent of age. Thus, in the absence of GCC thinning and cataracts, vitreous changes may be a cause of decreased CSF with age.

  3. Flow inside an eye under vitreous surgery

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    Kono, Daiki; Sakamoto, Shun; Sakakibara, Jun

    2014-11-01

    Vitreous is a clear gel filling the space between crystalline lens and retina in human eye. Under circumstances where the vitreous becomes opaque due to bleeding or other disease, ophthalmologist removes the vitreous from eye by cutting and sucking through a pipe named vitreous cutter, and meanwhile replaces fluid in the eye with a balanced salt solution by injecting it through the infusion port. Jet flow from the infusion port may cause intense flow. Consequently, this may generate a pressure and a shear stress on the retinal wall and possibly lead to the damage of retinal cell. In this study, we visualized the flow inside eye and estimated the shear stress on the retinal wall under the vitreous surgery. Instead of using human eye, we used a spherical shell model simulating human eyeball, and measured the two dimensional distribution of two-component velocity by PIV. Under the condition of Re=66 to 99, which meet in the actual operation, the maximum shear stress reaches 0.4 Pa. This value is insufficient to cause retinal detachment, while any physiological effect on the retinal endothelial cells is still unclear. Flow field under higher Re will be presented in the talk. Supported by Grants-in-Aid for Scientific Research of Japan Society for the Promotion of Science under Grant No. 25289026.

  4. Vitreous floaters (Conference Presentation)

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    Kershaw, K.; Nguyen, Derek; Yee, Kenneth; Nguyen, Justin A.; Harrington, Michael G.; Sebag, Jerry

    2017-02-01

    BACKGROUND: Vitreous opacities and posterior vitreous detachment (PVD) disturb vision by degrading contrast sensitivity (AJO 172:7-12, 2016). Increased light scattering is the presumed mechanism. To test this hypothesis, dynamic light scattering (DLS) was performed on excised vitreous of patients with clinically significant floaters, and compared to macular pucker controls. METHODS: Undiluted, unfixed vitreous was procured during 25-gauge vitrectomy in 14 subjects (age = 59 +/- 6.6 years) with clinically significant vitreous floaters, and 6 controls (age = 66.5 +/- 8.7 years; P = 0.10) with macular pucker. Total protein concentration was determined by fluorescent Quant-iTTM protein assay kit (Invitrogen/Molecular Probes, Eugene, OR) with bovine serum albumin (0500 ng/ml) as a standard. Fluorescence (excitation at 470 nm and emission at 570 nm) was measured using a Gemini XPS Dual-Scanning Microplate Spectrofluorometer and data analyzed using SoftMax Pro software (Molecular Devices, Sunnyvale, CA). DLS (NS300, Malvern Instruments, Westborough, MA) measurements were performed in each specimen after 10-fold dilution in phosphate buffered saline to optimize concentration in each specimen and determine the mean number of particles, the particle size distributions, and the average particle sizes. RESULTS: Total protein concentration in vitreous specimens trended higher in macular pucker controls (1037 +/- 1038 μg/mL) than eyes with vitreous floaters (353.7 +/- 141.1 μg/mL P = 0.08). When normalized to total protein concentration, the number of particles in vitreous from floater eyes was more than 2-fold greater than controls (P AJO 172:7-12, 2016). DLS could elucidate the underlying molecular abnormalities in patients afflicted with bothersome vitreous floaters and help develop clinical tools to better measure vitreous floaters as well as test the efficacy of various therapies.

  5. Vitreous vascular endothelial growth factor concentrations in proliferative diabetic retinopathy versus proliferative vitreoretinopathy.

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    Citirik, Mehmet; Kabatas, Emrah Utku; Batman, Cosar; Akin, Kadir Okhan; Kabatas, Naciye

    2012-01-01

    To assess vitreous vascular endothelial growth factor (VEGF) concentrations in proliferative diabetic retinopathy (PDR) in comparison to proliferative vitreoretinopathy (PVR). Vitreous samples were collected from 69 eyes of 69 patients with traumatic lens dislocation (n = 10), grade B PVR with rhegmatogenous retinal detachment (n = 13), grade C PVR with rhegmatogenous retinal detachment (n = 14), PDR with vitreous hemorrhage (n = 18), and PDR with vitreous hemorrhage and tractional retinal detachment (n = 14). Vitreous fluid samples were obtained at vitrectomy, and the levels of VEGF were measured by enzyme-linked immunosorbent assay. The mean vitreous level of VEGF was 15.14 ± 5.22 pg/ml in eyes with grade B PVR, 99.15 ± 38.58 pg/ml in eyes with grade C PVR, 4,534.01 ± 1,193.28 pg/ml in eyes with vitreous hemorrhage secondary to PDR, 5,157.29 ± 969.44 pg/ml in eyes with vitreous hemorrhage and tractional retinal detachment secondary to PDR, and 16.19 ± 5.76 pg/ml in eyes of the control group with traumatic lens dislocation. Vitreous VEGF concentrations were significantly higher in the patients with grade C PVR, PDR with vitreous hemorrhage and PDR with vitreous hemorrhage and tractional retinal detachment in comparison to the control patients (p < 0.05). A significant alteration was not observed in patients with grade B PVR (p = 0.55). Vitreous VEGF concentrations are increased in PDR and grade C PVR. The high VEGF concentrations could suggest a possible effect of VEGF on advanced PVR. Copyright © 2011 S. Karger AG, Basel.

  6. Variations of posterior vitreous detachment

    OpenAIRE

    Kakehashi, A.; Kado, M.; Akiba, J.; Hirokawa, H.

    1997-01-01

    AIMS—To identify variations in posterior vitreous detachment (PVD) and establish a clinical classification system for PVD.
METHODS—400 consecutive eyes were examined using biomicroscopy and vitreous photography and classified the PVD variations—complete PVD with collapse, complete PVD without collapse, partial PVD with thickened posterior vitreous cortex (TPVC), or partial PVD without TPVC.
RESULTS—In each PVD type, the most frequently seen ocular pathologies were as follows: in complete PVD ...

  7. Results of phacoemulsification of cataract complicated by lens subluxation depending on the ring setting method

    Directory of Open Access Journals (Sweden)

    N. G. Zavgorodnjaja

    2015-02-01

    Full Text Available Actuality. Cataract extraction complicated by zonular weakness remains one of the urgent problems of eye microsurgery. Aim. To increase the efficiency of cataract surgery complicated by lens subluxation through comparative analysis of frequency and structure of intra- and postoperative complications, as well as the functional results of surgical treatment of patients depending on the ring setting method. Methods and results. 91 patients (93 eyes were examined, who were operated on complicated cataract, and were divided into 2 groups depending on the method of ring setting. Conclusion. It was established that the offered method of implant capsular ring gives the opportunity to reduce the length of patients’ treatment by 2,6 day, to decrease of 28,43% for complications, and also to avoid such heavy operating complications, as a vitreous prolapse, displacement of the eye lens fragments in a vitreous body, dug up capsule bag.

  8. Scleral suspension pars-plana lensectomy for ectopia lentis followed by suture fixation of intraocular lens

    Directory of Open Access Journals (Sweden)

    Mitra Sandip

    2001-01-01

    Full Text Available Purpose: To describe a simple technique of scleral suspension-pars plana lensectomy (SS-PPL in acquired and congenital ectopia lentis and scleral fixation of intraocular lens (IOL. Materials and Methods: Twenty eyes of 16 patients (12 unilateral and 4 bilateral cases of "essential familial lens subluxation" aged 10-40 years (mean 25 years underwent SS-PPL with implantation of scleral fixated IOL. Indications for surgery were best-corrected visual acuity <6/18, bisection of pupil by the lens, and lens-induced glaucoma. Prerequisites for SS-PPL were, visibility of part of the lens in the pupillary area and soft lens. Results: Postoperative visual acuity ranged from 6/6 - 6/36. Lens tilt in 3 cases(15% and small decentration in 2 cases(10% were seen; however these did not seriously compromise the visual result. Scant vitreous bleeding on the first postoperative day was seen in 3 cases (15%. Conclusion: The advantages of the scleral suspension of subluxated lens prior to lensectomy include stabilization; it allows proper viewing of the lens, avoids injury to the iris and cliary body during lensectomy and reduces the possibility of dislocation of the lens.

  9. [The vitreous and the macula].

    Science.gov (United States)

    Kishi, Shoji

    2015-03-01

    The macula is a site where various vitreoretinal disorders occur. In 1983 we started to observe the retinal surface of postmortem eyes with a scanning electron microscope (SEM). We investigated the anatomy of the vitreous in postmortem eyes by slit lamp biomicroscopy. The novel anatomy of the premacular vitreous led us to conduct a clinical study of vitreomacular interface diseases. In 1997, time domain optical coherence tomography(OCT) became available which facilitated visualization of the vitreoretinal interface. Swept source OCT which was introduced in 2012 can depict liquefied lacunae in the vitreous. It enabled us to elucidate the mechanism of vitreoretinal diseases. I. SEM revealed the remnants of vitreous cortex at fovea with high incidence (44%), which suggests strong vitreoretinal attachment at the fovea and vitreous cortex origin of the epiretinal membrane. II. We studied the anatomy of the vitreous in postmortem eyes. The vitreous of bisected eye balls was stained by fluorescein and immersed in water and observed by slit-lamp biomicroscopy. We discovered a "posterior precortical vitreous pocket (PPVP)" in adult eyes without posterior vitreous detachment (PVD). III. We performed clinical study in various vitreoretinal diseases based on the novel vitreous anatomy and explained their mechanism. 1. In diabetic retinopathy, ring shaped fibrovascular tissue surrounding the macula is formed along the outer margin of the PPVP. Although PVD progresses outside the PPVP, its posterior wall remains attached to the retina, which causes macular traction or cystoid macular edema. 2. In eyes with idiopathic epimacular membrane (IEM), detached vitreous cortex had an oval defect corresponding to the IEM. Posterior wall of the PPVP that is premacular vitreous cortex appeared to be the framework of IEM. 3. During vitrectomy for macular hole, premacular round defect appears when PVD is created. The residual cortex on the macula is fibrous membrane with elasticity. The

  10. Proteomic Analyses of the Vitreous Humour

    Directory of Open Access Journals (Sweden)

    Martina Angi

    2012-01-01

    Full Text Available The human vitreous humour (VH is a transparent, highly hydrated gel, which occupies the posterior segment of the eye between the lens and the retina. Physiological and pathological conditions of the retina are reflected in the protein composition of the VH, which can be sampled as part of routine surgical procedures. Historically, many studies have investigated levels of individual proteins in VH from healthy and diseased eyes. In the last decade, proteomics analyses have been performed to characterise the proteome of the human VH and explore networks of functionally related proteins, providing insight into the aetiology of diabetic retinopathy and proliferative vitreoretinopathy. Recent proteomic studies on the VH from animal models of autoimmune uveitis have identified new signalling pathways associated to autoimmune triggers and intravitreal inflammation. This paper aims to guide biological scientists through the different proteomic techniques that have been used to analyse the VH and present future perspectives for the study of intravitreal inflammation using proteomic analyses.

  11. Classification of posterior vitreous detachment

    Science.gov (United States)

    Kakehashi, Akihiro; Takezawa, Mikiko; Akiba, Jun

    2014-01-01

    Diagnosing a posterior vitreous detachment (PVD) is important for predicting the prognosis and determining the indication for vitreoretinal surgery in many vitreoretinal diseases. This article presents both classifications of a PVD by slit-lamp biomicroscopy and of a shallow PVD by optical coherence tomography (OCT). By biomicroscopy, the vitreous condition is determined based on the presence or absence of a PVD. The PVD then is classified as either a complete posterior vitreous detachment (C-PVD) or a partial posterior vitreous detachment (P-PVD). A C-PVD is further divided into a C-PVD with collapse and a C-PVD without collapse, while a P-PVD is divided into a P-PVD with shrinkage of the posterior hyaloid membrane (P-PVD with shrinkage) and a P-PVD without shrinkage of the posterior hyaloid membrane (P-PVD without shrinkage). A P-PVD without shrinkage has a subtype characterized by vitreous gel attachment through the premacular hole in a posterior hyaloid membrane to the macula (P-PVD without shrinkage [M]). By OCT, a shallow PVD is classified as the absence of a shallow PVD or as a shallow PVD. A shallow PVD is then subclassified as a shallow PVD without shrinkage of the posterior vitreous cortex, a shallow PVD with shrinkage of the posterior vitreous cortex, and a peripheral shallow PVD. A shallow PVD without shrinkage of the posterior vitreous cortex has two subtypes: an age-related shallow PVD and a perifoveal PVD associated with a macular hole. PMID:24376338

  12. 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

    Science.gov (United States)

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

    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, biomicroscopy, and indirect ophthalmoscopy at baseline and 1, 7, 30, and 180 days postoperatively. Ultrasonography and aberrometry were performed. The Visual Functioning Questionnaire 25 (VFQ-25) was administered preoperatively and at 30 days postoperatively. Both the postoperative UCVA and questionnaire results were compared to preoperative findings using the Wilcoxon test. Results. Sixteen eyes of 8 patients were included. VA significantly improved from 0.17 to 0.09 postoperatively (P = 0.017). All patients reported improvement of halos, glare, and floaters. VFQ-25 scores significantly improved in general vision (P = 0.023), near activities (P = 0.043), distance activities (P = 0.041), mental health (P = 0.011), role difficulties (P = 0.042), and driving (P = 0.016). Conclusion. PPV may increase UCVA and quality of vision in patients with bilateral multifocal IOLs and symptomatic PVD. Larger studies are advised. PMID:26504590

  13. Remodeling of the adult human vitreous and vitreoretinal interface : a dynamic process

    NARCIS (Netherlands)

    Ponsioen, Theodorus Leonardus

    2008-01-01

    The vitreous body (or vitreous) of the human eye is an almost acellular, transparent loose-meshed connective tissue consisting mainly of water (99%) and of just 0.1% macromolecules, such as glycosaminoglycans (e.g. hyaluronan), proteoglycans, glycoproteins (such as opticin), collagens, and

  14. Raman spectroscopy of human vitreous collagen in diabetic retinopathy

    Science.gov (United States)

    Sebag, Jerry; Nie, Shuming; Reiser, Karen M.; Yu, Nai-Teng

    1992-08-01

    In diabetes nonenzymatic glycation alters collagen throughout the body resulting in the histopathology that underlies diabetic disease in several organs. In the eye such changes in vitreous collagen could contribute to vitreous degeneration and the progression of proliferative diabetic retinopathy. Previous studies have demonstrated early glycation and advanced endproducts in the vitreous of humans with proliferative diabetic retinopathy. Near-infrared Fourier-transform Raman spectroscopy was performed on vitreous obtained at surgery from diabetic patients and from non-diabetic control subjects. The findings were compared to measurements obtained in untreated and glycated (in vitro) rat-tail tendon collagen. The results demonstrated substantial changes in diabetic vitreous collagen resulting from glycation, most likely advanced glycation endproducts. This approach appears to be useful as a means of characterizing the molecular changes induced by diabetes. Furthermore, this technique could be developed as a way of quantifying these changes in vivo in several tissues, so as to gauge the severity of non-enzymatic glycation and monitor the response to therapy.

  15. Mixing processes in the vitreous chamber induced by eye rotations

    International Nuclear Information System (INIS)

    Stocchino, Alessandro; Repetto, Rodolfo; Siggers, Jennifer H

    2010-01-01

    In this paper, we study a model of flow in the vitreous humour in the posterior chamber of the human eye, induced by saccadic eye rotations. We concentrate on the effect of the shape of the chamber upon the mixing properties of the induced flows. We make particle image velocimetry measurements of the fluid velocity in a transparent plastic (Perspex) model of the posterior chamber during sinusoidal torsional oscillations about a vertical axis. We use a Newtonian fluid to model the vitreous humour, which is most realistic when either the vitreous humour is liquefied or has been replaced by purely viscous tamponade fluids. The model of the posterior chamber is a sphere with an indentation, representing the effect of the lens. In spite of the purely periodic forcing, a steady streaming flow is generated, which plays a fundamental role in the mixing processes in the domain. The streaming flow differs markedly from that in a perfect sphere, and its topological characteristics change substantially as the frequency of oscillation varies. We discuss the flow characteristics in detail and show that, for physiological parameter values, the Peclet number (based on a suitable measure of the steady streaming velocity) is large, suggesting that advection strongly dominates over diffusion for mass transport phenomena. We also compute particle trajectories based on the streaming velocity and use these to investigate the stirring properties of the flow.

  16. Classification of posterior vitreous detachment

    OpenAIRE

    Kakehashi, Akihiro; Takezawa, Mikiko; Akiba, Jun

    2013-01-01

    Akihiro Kakehashi,1 Mikiko Takezawa,1 Jun Akiba21Department of Ophthalmology, Jichi Medical University, Saitama Medical Center, Saitama, 2Kanjodori Eye Clinic, Asahikawa, JapanAbstract: Diagnosing a posterior vitreous detachment (PVD) is important for predicting the prognosis and determining the indication for vitreoretinal surgery in many vitreoretinal diseases. This article presents both classifications of a PVD by slit-lamp biomicroscopy and of a shallow PVD by optical coherence tomography...

  17. Refractive shifts in four selected artificial vitreous substitutes based on Gullstrand-Emsley and Liou-Brennan schematic eyes.

    Science.gov (United States)

    Gao, Qianying; Chen, Xiang; Ge, Jian; Liu, Yongji; Jiang, Zhaoxin; Lin, Zhi; Liu, Yaqin

    2009-07-01

    To determine and compare the refractive shifts based on Gullstrand-Emsley and Liou-Brennan schematic eyes after filling them with four selected artificial vitreous substitutes: silicone oil, heavy silicone oil, hydrogels, and encapsuled balanced salt solution. The optical constants of artificial vitreous body-filled eyes were calculated based on Gullstrand-Emsley and Liou-Brennan schematic eyes with accommodation relaxed. The theoretical refractive shifts in these two models were compared in pars plana vitrectomy (PPV), PPV plus lensectomized and PPV plus intraocular lens (IOL) eyes after four artificial vitreous tamponades. The Gullstrand-Emsley schematic eye shows refractive shifts of +8.710, -4.544, +1.136, and -0.338 D in PPV eyes; +11.044, +20.332, +16.351, and +17.413 D in PPV plus lensectomized eyes; and the need for IOL powers of +22.195, +22.366, +22.292, and +22.312 D in PPV plus IOL eyes in silicone oil, heavy silicone oil, hydrogels, and encapsuled balanced salt solution tamponade eyes, respectively. Similarly, the Liou-Brennan schematic eye induced shifts of +6.260, -3.266, +0.817, and -0.272 D in PPV eyes; +13.181, +20.654, +17.451, and +18.305 D in PPV plus lensectomized eyes; and the need IOL powers of +13.522, +23.767, +19.389, and +20.558 D in PPV plus IOL eyes, respectively. The Gullstrand-Emsley schematic eye is a convenient and accurate model for predicting refractive shifts for hydrogels and encapsuled balanced salt solution substitutes in PPV eyes. The Liou-Brennan schematic eye is recommended for silicone oil and heavy silicone oil in PPV eyes and for all four substitutes in PPV plus lensectomized eyes and PPV plus IOL eyes. In addition, the encapsuled balanced salt solution changes the refraction little in either schematic eye.

  18. Posterior vitreous detachment and retinal detachment after cataract surgery.

    Science.gov (United States)

    Ripandelli, Guido; Coppé, Andrea Maria; Parisi, Vincenzo; Olzi, Diego; Scassa, Cecilia; Chiaravalloti, Adele; Stirpe, Mario

    2007-04-01

    To evaluate possible changes of vitreous status in emmetropic eyes after uneventful phacoemulsification surgery, and possible related complications such as the onset of retinal detachment (RD). Retrospective case series. Four hundred fifty-three emmetropic eyes from 453 patients (mean age, 62.03+/-5.57 years) subjected to uneventful phacoemulsification with intraocular lens implantation in the capsular bag were considered in the study. They had a refractive error within +/-0.5 diopters (mean, -0.21+/-0.08). Eyes with peripheral retinal lattice degeneration were included only if asymptomatic and only if the degeneration involved one retinal quadrant. After cataract surgery, the 453 eyes were evaluated preoperatively at days 1, 15, and 30 and months 3, 6, 12, 18, 24, 36, 48, and 60. The whole period of follow-up was 5 years. Evaluation of vitreous status by biomicroscopic examination, indirect binocular ophthalmoscopy, and B-scan ultrasonography. Postoperative onset of posterior vitreous detachment (PVD) and RD. After cataract surgery, a PVD occurred in 107 of 141 (75.88%) eyes without preoperative PVD or lattice degeneration. Posterior vitreous detachment occurred in 41 of 47 eyes (87.23%) with preoperative lattice degeneration and no PVD. Eyes with preoperative lattice degeneration and postoperative PVD showed a higher incidence of RD after cataract surgery (21.27%) than eyes without preoperative PVD or lattice degeneration (0.70%). In all patients with lattice degeneration, RD originated from horseshoe retinal tears on lattice areas located on the superior quadrants. No correlation was observed between the development of RD and age. Our results suggest that the onset of postoperative PVD should be considered an important risk factor for the development of RD after cataract surgery, particularly in eyes with lattice areas.

  19. Computed tomography in the evaluation of patients with persistent hyperplastic primary vitreous (PHPV)

    International Nuclear Information System (INIS)

    Mafee, M.F.; Goldberg, M.F.; Valvassori, G.E.; Capek, V.

    1982-01-01

    The computed tomographic (CT) findings in 5 patients with proven persistent hyperplastic primary vitreous (PHPV) are described. PHPV arises when the embryonic hyaloid vascular system fails to regress normally. Clinically, this condition usually manifests an unilateral or bilateral leukokoria and is one of the more important and frequent conditions mimicking retinoblastoma. The spectrum of CT findings include: (a) soft-tissue replacement (infiltration) of the vitreous body; (b) retrolental soft tissue along the Cloquet canal; (c) absence of abnormal calcification within the orbit; (d) microphthalmus; (e) retrohyaloid layered blood; and (f) hypervascularity in the vitreous humor

  20. Experiment of vitreous liquefaction induced by C3F8.

    Science.gov (United States)

    Wang, Jing; Li, Qiuming

    2017-01-01

    To investigate the effect and safety of vitreous liquefaction induced by C3F8 (an inert gas) injected into vitreous cavit of rabbit eyes. 24 rabbits (48 eyes) were randomly divided into four groups, named group A, group B, group C and group D, with 6 rabbits in each group. The right eye in each rabbit was taken as the experimental eye while the left as the control eye. The experimental eyes in group A were injected with 0.1mL disinfectant air; the experimental eyes in group B, group C and group D were all injected with C3F8 0.1mL, 0.2mL and 0.3mL respectively after receiving anterior chamber penetration; and the controlled eyes in all group were injected with 0.1mL balanced salt solution (BSS). During the first 7 d after injection, all the rabitts' eyes were examined by slit lamp, ophthalmoscope, intraocular pressure (IOP) and dark-adapted retina Electroretinography (ERG) each day. After that, the examination of IOG and ERP were reviewed weekly. Besides, B ultrasound should be examined to observe the situation of posterior vitreous detachment (PVD) in the 4th and 8th weeks. The rabbits were killed in the end of the 8th week, with their specimens examined by the light microscope, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Except group A, all the experimental eyes were produced with vitreous liquefaction. In group C and group D, in addition to the produced vitreous liquefaction, posterior vitreous detachment (PVD), even complete PVD, were induced in different extent. But in group B, the vitreous body was returned to the gel state at 2 weeks after gas absorption. In group C and group D, the vitreous body was not found to recover its original state at 8 weeks. In group D, there was a little increase of intraocular pressure, a mild delay of wave a and wave b after ERG in the 4th day after the gas injection. While there was no such situation in other groups. After the examination of B ultrasound in the 8th week, the complete PVD

  1. Vitreous in lattice degeneration of retina.

    Science.gov (United States)

    Foos, R Y; Simons, K B

    1984-05-01

    A localized pocket of missing vitreous invariably overlies lattice degeneration of the retina. Subjects with lattice also have a higher rate of rhegmatogenous retinal detachment, which is usually a complication of retinal tears. The latter are in turn a result of alterations in the central vitreous--that is, synchysis senilis leading to posterior vitreous detachment. In order to determine if there is either an association or a deleterious interaction between the local and central lesions of the vitreous in eyes with lattice, a comparison was made in autopsy eyes with and without lattice the degree of synchysis and rate of vitreous detachment. Results show no association between the local and central vitreous lesions, indicating that a higher rate of vitreous detachment is not the basis for the higher rate of retinal detachment in eyes with lattice. Also, there was no suggestion of deleterious interaction between the local and central vitreous lesions, either through vitreodonesis as a basis for precocious vitreous detachment, or through a greater degree of synchysis as a basis for interconnection of local and central lacunae (which could extend the localized retinal detachment in eyes with holes in lattice degeneration).

  2. Detection of ketosis in vitreous at autopsy after embalming.

    Science.gov (United States)

    Steinhauer, Jon R; Volk, Andrea; Hardy, Robert; Konrad, Robert; Daly, Tom; Robinson, C Andrew

    2002-01-01

    Ketosis occurs in ketoacidosis or malnourishment. When either is suspected in relation to a death, it may be important to analyze for ketosis at autopsy. We encountered a case where starvation was suspected in a deceased nursing home resident, where the body had been embalmed prior to autopsy. Gas chromatography (GC) was unable to separate acetone from formaldehyde, a component of embalming fluid. The Acetest is a simple test that can detect acetone and acetoacetate in body fluids. We validated the Acetest with GC on vitreous. The Acetest and GC were consistent except at very low levels of acetone or acetoacetate. The sensitivity of the Acetest for acetoacetate in vitreous was 10 mg/dL, consistent with early starvation. Significant interference from embalming fluid did not occur. The Acetest was negative in the described case. The Acetest is a simple and useful test for the detection of ketosis in embalmed autopsies.

  3. Thanatochemistry: Study of vitreous humor potassium | Tumram ...

    African Journals Online (AJOL)

    This study has been carried out to determine the death interval from the biochemical parameter of vitreous potassium. In 308 medicolegal cases vitreous humor was taken and analyzed for potassium with known time of death. There was a linear rise in potassium concentration with increasing death interval. Regression ...

  4. Association of the nuclear matrix component NuMA with the Cajal body and nuclear speckle compartments during transitions in transcriptional activity in lens cell differentiation.

    Science.gov (United States)

    Gribbon, Chris; Dahm, Ralf; Prescott, Alan R; Quinlan, Roy A

    2002-10-01

    The transcriptional status of cells can be deduced from the staining pattern of various nuclear markers such as the Cajal body, nucleolus and nuclear speckles. In this study we have used these markers to correlate transcriptional status with cell differentiation in the lens. As a closed system with no cell loss and with each stage being spatially preserved, it is particularly well suited to such studies. To confirm that the nuclear markers in lens cells follow the same trends as in other cells, primary bovine lens epithelial cells were cultured and then treated with actinomycin D to inhibit transcription. This reduced the Cajal body markers to one or two foci per nucleus and the nucleoli became compacted as revealed by fibrillarin staining. The nuclear speckles, containing snRNPs (e.g. Sm) and the splicing factor, SC35, also became larger and more numerous while the signal for trimethylguanine (TMG) decreased suggesting a role hierarchy for the various speckle factors during transcriptional shutdown. The signal for survival of motor neurones gene product (SMN) also decreased at this point. In the lens epithelium, postmitotic cells near the equatorial region had one or two Cajal bodies per nucleus, indicating these cells had only basal levels of transcription. Sm was also present as large foci in these cells. Interestingly, both the speckles and Cajal bodies were NuMA-positive in these post-mitotic cells. At the epithelial-fibre cell transition, Cajal body number increased, while their size decreased indicative of increased transcriptional activity. Fibrillarin adopted the open floret pattern indicating increased transcriptional activity. The nuclear speckles adopted a more diffuse nucleoplasmic pattern, although some spots were still observed. All NuMA colocalisation with the Cajal bodies and nuclear speckles was lost at this stage of lens cell differentiation. Transcriptional shutdown occurs at a later stage in fibre cell differentiation, prior to programmed

  5. Efficiency of radiation protection equipment in interventional radiology: a systematic Monte Carlo study of eye lens and whole body doses

    International Nuclear Information System (INIS)

    Koukorava, C; Farah, J; Clairand, I; Donadille, L; Struelens, L; Vanhavere, F; Dimitriou, P

    2014-01-01

    Monte Carlo calculations were used to investigate the efficiency of radiation protection equipment in reducing eye and whole body doses during fluoroscopically guided interventional procedures. Eye lens doses were determined considering different models of eyewear with various shapes, sizes and lead thickness. The origin of scattered radiation reaching the eyes was also assessed to explain the variation in the protection efficiency of the different eyewear models with exposure conditions. The work also investigates the variation of eye and whole body doses with ceiling-suspended shields of various shapes and positioning. For all simulations, a broad spectrum of configurations typical for most interventional procedures was considered. Calculations showed that ‘wrap around’ glasses are the most efficient eyewear models reducing, on average, the dose by 74% and 21% for the left and right eyes respectively. The air gap between the glasses and the eyes was found to be the primary source of scattered radiation reaching the eyes. The ceiling-suspended screens were more efficient when positioned close to the patient’s skin and to the x-ray field. With the use of such shields, the H p (10) values recorded at the collar, chest and waist level and the H p (3) values for both eyes were reduced on average by 47%, 37%, 20% and 56% respectively. Finally, simulations proved that beam quality and lead thickness have little influence on eye dose while beam projection, the position and head orientation of the operator as well as the distance between the image detector and the patient are key parameters affecting eye and whole body doses. (paper)

  6. Efficiency of radiation protection equipment in interventional radiology: a systematic Monte Carlo study of eye lens and whole body doses.

    Science.gov (United States)

    Koukorava, C; Farah, J; Struelens, L; Clairand, I; Donadille, L; Vanhavere, F; Dimitriou, P

    2014-09-01

    Monte Carlo calculations were used to investigate the efficiency of radiation protection equipment in reducing eye and whole body doses during fluoroscopically guided interventional procedures. Eye lens doses were determined considering different models of eyewear with various shapes, sizes and lead thickness. The origin of scattered radiation reaching the eyes was also assessed to explain the variation in the protection efficiency of the different eyewear models with exposure conditions. The work also investigates the variation of eye and whole body doses with ceiling-suspended shields of various shapes and positioning. For all simulations, a broad spectrum of configurations typical for most interventional procedures was considered. Calculations showed that 'wrap around' glasses are the most efficient eyewear models reducing, on average, the dose by 74% and 21% for the left and right eyes respectively. The air gap between the glasses and the eyes was found to be the primary source of scattered radiation reaching the eyes. The ceiling-suspended screens were more efficient when positioned close to the patient's skin and to the x-ray field. With the use of such shields, the Hp(10) values recorded at the collar, chest and waist level and the Hp(3) values for both eyes were reduced on average by 47%, 37%, 20% and 56% respectively. Finally, simulations proved that beam quality and lead thickness have little influence on eye dose while beam projection, the position and head orientation of the operator as well as the distance between the image detector and the patient are key parameters affecting eye and whole body doses.

  7. EURADOS intercomparisons in external radiation dosimetry: similarities and differences among exercises for whole-body photon, whole-body neutron, extremity, eye-lens and passive area dosemeters

    International Nuclear Information System (INIS)

    Romero, Ana M.; Grimbergen, Tom; McWhan, Andrew; Stadtmann, Hannes; Fantuzzi, Elena; Clairand, Isabelle; Neumaier, Stefan; Dombrowski, Harald; Figel, Markus

    2016-01-01

    The European Radiation Dosimetry Group (EURADOS) has been organising dosimetry intercomparisons for many years in response to an identified requirement from individual monitoring services (IMS) for independent performance tests for dosimetry systems. The participation in intercomparisons gives IMS the opportunity to show compliance with their own quality management system, compare results with other participants and develop plans for improving their dosimetry systems. In response to growing demand, EURADOS has increased the number of intercomparisons for external radiation dosimetry. Most of these fit into the programme of self-financing intercomparisons for dosemeters routinely used by IMS. This programme is being coordinated by EURADOS working group 2 (WG2). Up to now, this programme has included four intercomparisons for whole-body dosemeters in photon fields, one for extremity dosemeters in photon and beta fields, and one for whole-body dosemeters in neutron fields. Other EURADOS working groups have organised additional intercomparisons including events in 2014 for eye-lens dosemeters and passive area dosemeters for environmental monitoring. In this paper, the organisation and achievements of these intercomparisons are compared in detail focusing on the similarities and differences in their execution. (authors)

  8. Outcome of Lens-Sparing Vitrectomy for Infantile Post-Traumatic ...

    African Journals Online (AJOL)

    DR OKONKWO_

    ABSTRACT. The visual outcome after bilateral lens-sparing 3-port pars plana vitrectomy in a case of post-traumatic vitreous haemorrhage in an infant is reported. Although it is possible to perform a vitrectomy procedure via a pars plana approach in infants without compromise to the lens for the treatment of amblyogenic ...

  9. Test of ring, eye lens and whole body dosemeters for the dose quantity Hp(3) to be used in interventional radiology

    Science.gov (United States)

    Szumska, A.; Budzanowski, M.; Kopeć, R.

    2017-11-01

    In its statement on tissue reactions approved on 21st April 2011, the International Commission on Radiological Protection (ICRP, 2012) reviewed its recommendation concerning the equivalent dose limit for the eye lens and reduced the dose limits for occupationally exposed persons to 20 mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. This limit was approved and written down in the new EURATOM (European Atomic Energy Community) directive 2013/59 and in the IAEA (International Atomic Energy Agency) BSS (Basic Safety Standard) of July 2014. For that reason, the necessity to monitor the eye lens may become more important than it was before. However, specially dedicated dosemeters for the dose quantity Hp(3) are using very rarely. Commonly use are only whole body personal dosemeters for the personal dose equivalent quantities Hp(10) worn on the trunk and ring dosemeters worn on finger to measure the quantity Hp(0.07). Therefore, in this work it was investigated whether dosemeters from routine use calibrated in terms of Hp(10) and Hp(0.07) and worn on thyroid collar and protective apron could deliver similar results like dedicated eye lens dosemeter worn close to the eyes. The results show that the best method if dedicated eye lens dosimeters is not used is to measure doses in terms of Hp(0.07) on the thyroid collar (Pearson product, r=0.85). Obtained results shows also importance of proper localization of eye lens dosimeter (close to the eye, from side of the X-ray source).

  10. Retrospective Study of Vitreous Tap Technique Using Needle Aspiration for Management of Shallow Anterior Chamber during Phacoemulsification

    Directory of Open Access Journals (Sweden)

    Ashraf Ahmed Nossair

    2017-01-01

    Full Text Available Purpose. To evaluate the technique of vitreous tap using needle aspiration for management of anterior chamber shallowness during phacoemulsification. Methods. A retrospective study included 26 eyes of 17 patients who underwent phacoemulsification in which vitreous tap was performed using a 27-gauge needle attached to a 5 ml syringe, inserted 3.5 mm from the limbus to aspirate 0.2 ml of liquefied vitreous if a cohesive (OVD failed to sufficiently deepen the anterior chamber. Results. Preoperative anterior chamber depth was 2.31 ± 0.26 mm, axial length was 21.7 ± 0.67 mm, lens thickness was 4.5 ± .19 mm, and cataract grade was 3.77 ± 1.4. Preoperative CDVA in LogMAR units was 0.98 ± 0.75. Coexisting angle closure glaucoma was present in 7 patients (26.92% preoperatively. Vitreous needle tap was successful in vitreous removal on the first attempt in 26 eyes (100%. Postoperative follow-up period was 22.88 ± 10.24 (4–39 months. The final postoperative CDVA in LogMAR units was 0.07 ± 0.1, while the final postoperative IOP was 16.54 ± 1.45 mmHg. No complications related to vitreous tap were noted. Conclusion. Vitreous needle tap is a simple, cost-effective, and safe technique for management of shallow anterior chamber in phacoemulsification.

  11. Developmental abnormalities of the vitreous in mouse fetuses caused by simultaneous irradiation of x-rays and ultrasound

    International Nuclear Information System (INIS)

    Shirai, Shoichiro; Yuguchi, Shuji; Majima, Akio

    1980-01-01

    Eye abnormalities in mouse fetuses caused by irradiation of X-rays alone, or simultaneous irradiation of X-rays and ultrasound on day 7 of gestation were histologically studied on day 18 of gestation. Developmental abnormalities of the vitreous were examined in the present experiment, and the following results were obtained. 1. Developmental abnormalities of the vitreous were observed in 23 fetused, and unilateral cases were 15 of 23 fetuses. In 31 eyes with these abnormalities, much more abundant mesenchymal tissue of components of primary vitreous was found in the retrolental vitreous cavity than in the normal eyes. 2. The above 31 eyes were also accompanied by a variety of ocular abnormalities such as microphthalmia, faulty closure of the fetal fissure, aplasia and hypoplasia of the optic nerve, goniodysgenesis, and corneolenticular adhesion. Complications observed to be associated with developmental abnormalities of the vitreous were lens abnormalities, retinal traction and fold, fibrovascular anastomosis between mesenchymal tissues of the chamber angle and vitrious cavity, retinal rosette, and anomalies of the optic nerve head. 3. The histological findings of 17 eyes corresponded to anterior persistent hyperplastic primary vitreous (PHPV) encountered clinically, those of 3 eyes to posterior PHPV, those of 6 eyes to mixed type of both anterior and posterior types, and those of 5 eyes to PHPV of the optic nerve head. In 3 bilateral cases, the type was different for either eye. 4. From these results, it was considered that the pathogenesis of PHPV of Reese and congenital retinal fold of Mann consists of the maldevelopment of the components of the primary vitreous, and that the type of defect is depends on the portion involved and the degree depends on the time at which the maldevelopment occurs. (author)

  12. Factors associated with pentosidine accumulation in the human vitreous

    NARCIS (Netherlands)

    Van Deemter, Marielle; Bank, Ruud A.; Vehof, Jelle; Hooymans, Johanna M. M.; Los, Leonoor I.

    Purpose: To explore factors associated with pentosidine accumulation in the human vitreous. Methods: Vitreous samples were obtained during trans pars plana vitrectomy for macular hole or rhegmatogenous retinal detachment. Patient characteristics included age, gender, and diabetes mellitus. Ocular

  13. Design of an Injectable in Situ Gelation Biomaterials for Vitreous Substitute

    DEFF Research Database (Denmark)

    Annaka, Masahiko; Mortensen, Kell; Vigild, Martin E.

    2011-01-01

    To adapt the physical properties of living materials to their biological function, nature developed various types of polymers with outstanding physical behavior. One example is the vitreous body, which is important intraocular elements not only because of its optical and mechanical performances, ...

  14. Relationship between Central Corneal Thickness, Vitreous ...

    African Journals Online (AJOL)

    The central corneal thickness (CCT), Vitreous chamber depth (VCD) and axial length (AL) are important ocular parameters used in the assessment of ocular health in relation to some ocular morbidities. Determining the differences in these parameters in relation to each other is fundamental to understanding the general eye ...

  15. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...

  16. Proteomic interactions in the mouse vitreous-retina complex.

    Directory of Open Access Journals (Sweden)

    Jessica M Skeie

    Full Text Available Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina.Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software.We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor.Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

  17. Accessory optical device for the Heidelberg retina angiograph ( HRA classic to perform angiography of the vitreous cavity and the anterior eye segment

    Directory of Open Access Journals (Sweden)

    Mennel Stefan

    2007-01-01

    Full Text Available The Heidelberg retina angiograph ( HRA classic enables fluorescein angiography (FA and indocyanine green angiography (ICG-A of the retina and choroid. The goal of this study was to design an accessory device to adapt the HRA classic for application on structures anterior to the retina. The optical device consisted of a cylindrical two-piece plastic frame holding a magnifying lens commonly used with the indirect ophthalmoscope. A 60-diopters lens was inserted in this frame to enable the angiography of the anterior segment. A less strong lens of 30 diopters was used for the visualization of pathologic findings in the vitreous cavity. We designed an easy-to-use and low-cost device to adapt the HRA classic for angiography of the fundus, vitreous cavity and anterior segment in the same session and without delay. FA and ICG-A images of two patients with rubeosis iridis and of one patient with choroidal melanoma are described.

  18. Continuous Curvilinear Capsulorhexis Training and Non-Rhexis Related Vitreous Loss: The Specificity of Virtual Reality Simulator Surgical Training (An American Ophthalmological Society Thesis).

    Science.gov (United States)

    McCannel, Colin A

    2017-08-01

    To assess the specificity of simulation-based virtual reality ophthalmic cataract surgery training on the Eyesi ophthalmic virtual reality surgical simulator, and test the hypothesis that microsurgical motor learning is highly specific. Retrospective educational interventional case series. The rates of vitreous loss and retained lens material, and vitreous loss and retained lens material associated with an errant continuous curvilinear capsulorhexis (CCC) were assessed among 1037 consecutive cataract surgeries performed during four consecutive academic years at a teaching hospital. The data were grouped by Eyesi use and capsulorhexis intensive training curriculum (CITC) completion. The main intervention was the completion of the CITC on the Eyesi. In the Eyesi simulator experience-based stratification, the vitreous loss rate was similar in each group (chi square p=0.95) and was not preceded by an errant CCC in 86.2% for "CITC done at least once", 57.1% for "CITC not done, but some Eyesi use", and 48.9% for "none" training groups (p=4×10-5). Retained lens material overall and occurring among the errant CCC cases was similar among training groups (p=0.82 and p=0.71, respectively). Eyesi capsulorhexis training was not associated with lower vitreous loss rates overall. However, non-errant CCC associated vitreous loss was higher among those who underwent Eyesi capsulorhexis training. Training focused on the CCC portion of cataract surgery may not reduce vitreous loss unassociated with an errant CCC. It is likely that surgical training is highly specific to the task being trained. Residents may need to be trained for all surgical steps with adequate intensity to minimize overall complication rates.

  19. ECTOPIC LENS EXTRACTION IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2002-12-01

    Full Text Available Background. Ectopia lentis continues to be a therapeutic challenge for ophthalmologists. It can occur as an isolated condition, after ocular trauma, in association with other ocular disorders, as part of a systemic mesodermal disease or a complication of general metabolic disorders. Minimal subluxation of the lens may cause no visual symptoms, but in more advanced cases serious optical disturbances arise. The most important is amblyopia. Surgical treatment options include iris manipulation, lens discission, aspiration, intracapsular or extracapsular extraction, and pars plana lensectomy. The choice of surgical technique remains controversial, in part because of the historically poor visual results and high rate of perioperative complications, including vitreous loss and retinal detachment.Methods. We describe a surgical technique based on the use of the Cionni endocapsular tension ring, dry irrigation aspiration of lens material, centration of the capsular bag and foldable intraocular lens implantation into the bag. With mentioned surgical technique 8 patients were operated; 4 boys and 4 girls, together 11 eyes.Results. The final BCVA after follow up period improved in 9 eyes and it remained the same as before operation in one eye. Statistical comparison of preoperative and postoperative visual acuities showed significant improvement. On the other hand there was no correlation between preoperative and postoperative visual acuity.Conclusions. This surgical procedure is an alternative approach in solving this challenging cases of ectopia lentis with good postoperative visual rehabilitation.

  20. Recent Advances and History of Vitreous Surgery

    Directory of Open Access Journals (Sweden)

    Tatsuya Mimura

    2011-01-01

    Full Text Available There have been tremendous advances in the small-gauge pars plana vitrectomy (PPV systems. This review provides an overview of the recent advances and state of the art of vitreous surgery. The two most innovative advancements that have been developed in this area are the small-gauge cutter and the new illuminating systems. Compared to the traditional 20-gauge PPV, transconjunctival sutureless small-gauge PPV is a safe and effective strategy to treat a variety of vitreoretinal diseases. Chandelier illumination allows better visualisation of vitreous for bimanual surgery. The small-gauge PPV provides benefits in terms of less inflammation, less patient discomfort, and faster recovery of the visual acuity.

  1. Convective transport resistance in the vitreous humor

    Science.gov (United States)

    Penkova, Anita; Sadhal, Satwindar; Ratanakijsuntorn, Komsan; Moats, Rex; Tang, Yang; Hughes, Patrick; Robinson, Michael; Lee, Susan

    2012-11-01

    It has been established by MRI visualization experiments that the convection of nanoparticles and large molecules with high rate of water flow in the vitreous humor will experience resistance, depending on the respective permeabilities of the injected solute. A set of experiments conducted with Gd-DTPA (Magnevist, Bayer AG, Leverkusen, Germany) and 30 nm gadolinium-based particles (Gado CELLTrackTM, Biopal, Worcester, MA) as MRI contrast agents showed that the degree of convective transport in this Darcy-type porous medium varies between the two solutes. These experiments consisted of injecting a mixture of the two (a 30 μl solution of 2% Magnevist and 1% nanoparticles) at the middle of the vitreous of an ex vivo whole bovine eye and subjecting the vitreous to water flow rate of 100 μl/min. The water (0.9% saline solution) was injected at the top of the eye, and was allowed to drain through small slits cut at the bottom of the eyeball. After 50 minutes of pumping, MRI images showed that the water flow carried the Gd-DTPA farther than the nanoparticles, even though the two solutes, being mixed, were subjected to the same convective flow conditions. We find that the convected solute lags the water flow, depending on the solute permeability. The usual convection term needs to be adjusted to allow for the filtration effect on the larger particles in the form (1- σ) u . ∇ c with important implications for the modeling of such systems.

  2. Retinal and vitreous metastases from hepatocholangiocarcinoma.

    Science.gov (United States)

    Praidou, Anna; Jacob, Sarita; Irion, Luciane; Sivaraj, Ramesh; Groenewald, Carl; Coupland, Sarah E; Heimann, Heinrich

    2017-06-19

    To report a case of metastatic hepatocholangiocarcinoma to the vitreous and retina. A 70-year-old male, who was recently diagnosed with hepatocholangiocarcinoma, was complaining of floaters in his right eye over the past 5 months and was referred to the Liverpool Ocular Oncology Centre. On presentation, his visual acuity in the right eye was 6/24. Fundus exam revealed a whitish, unilateral, full-thickness retinal lesion at the inferotemporal arcade of his right eye, with vitreous infiltration and subretinal fluid. The patient underwent 25G pars plana vitrectomy with biopsy, resection of the lesion and intravitreal bevacizumab injection. Histopathology testing of the surgical specimens confirmed the diagnosis of metastatic carcinoma to the eye. Two months postoperatively his visual acuity had improved to 6/7.5 and there was no sign of active disease in his right eye, while 9 months postoperatively his visual acuity decreased to 6/9.5 due to developing nuclear sclerotic cataract in his right eye. The current report presents the first case of a hepatocholangiocarcinoma metastasis to the vitreous and retina.

  3. Lens Subluxation after Plasmin and SF6 Injections in Rabbit Eyes

    Science.gov (United States)

    Wu, Wei-Chi; Liu, Chi-Hsien; Wang, Nan-Kai; Chen, Kwan-Jen; Chen, Tun-Lu; Hwang, Yih-Shiou; Liao, Pei-Ju; Li, Lien-Min; Lai, Chi-Chun

    2014-01-01

    Purpose To investigate the rate of lens subluxation following plasmin and/or SF6 injections in eyes, and whether a subsequent elevated level of vascular endothelial growth factor (VEGF) and vitreous tap would aggravate subluxation. Methods Four groups of rabbits were used. Group 1 received an intravitreal injection (IVI) of plasmin and SF6 in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF6 in the right eye; and group 4 received an IVI of balanced salt solution in the right eye. After treatment, IVIs of VEGF were given and vitreous tap was performed three times, followed by clinical observation of lens subluxation and scanning electronic microscope evaluation of the zonular fibers. Results After IVIs of plasmin and SF6, and VEGF and vitreous tap had been performed one to three times, lens subluxation was noted in 0%, 43%, 71%, 71%, and 86% of the eyes in group 1. After IVIs of plasmin, VEGF, and vitreous tap had been performed one to three times, lens subluxation was noted in 11%, 22%, 44%, 44%, and 67% of the eyes in group 2. The eyes in group 3 and 4 did not show signs of lens subluxation after VEGF IVIs and vitreous tap. Histology confirmed zonular fiber damage in the eyes treated with plasmin. Conclusions The incidence of lens subluxation increased following plasmin injections in the eyes, and this was aggravated by the subsequent high VEGF level in the eyes and vitreous tapping. Zonular fibers were disrupted following plasmin treatment. These effects should be kept in mind when using plasmin enzymes in patients with vitreoretinal abnormalities. PMID:25397749

  4. Lens subluxation after plasmin and SF6 injections in rabbit eyes.

    Directory of Open Access Journals (Sweden)

    Wei-Chi Wu

    Full Text Available To investigate the rate of lens subluxation following plasmin and/or SF6 injections in eyes, and whether a subsequent elevated level of vascular endothelial growth factor (VEGF and vitreous tap would aggravate subluxation.Four groups of rabbits were used. Group 1 received an intravitreal injection (IVI of plasmin and SF6 in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF6 in the right eye; and group 4 received an IVI of balanced salt solution in the right eye. After treatment, IVIs of VEGF were given and vitreous tap was performed three times, followed by clinical observation of lens subluxation and scanning electronic microscope evaluation of the zonular fibers.After IVIs of plasmin and SF6, and VEGF and vitreous tap had been performed one to three times, lens subluxation was noted in 0%, 43%, 71%, 71%, and 86% of the eyes in group 1. After IVIs of plasmin, VEGF, and vitreous tap had been performed one to three times, lens subluxation was noted in 11%, 22%, 44%, 44%, and 67% of the eyes in group 2. The eyes in group 3 and 4 did not show signs of lens subluxation after VEGF IVIs and vitreous tap. Histology confirmed zonular fiber damage in the eyes treated with plasmin.The incidence of lens subluxation increased following plasmin injections in the eyes, and this was aggravated by the subsequent high VEGF level in the eyes and vitreous tapping. Zonular fibers were disrupted following plasmin treatment. These effects should be kept in mind when using plasmin enzymes in patients with vitreoretinal abnormalities.

  5. A case report of intraocular lens luxation with the capsular bag after vitrectomy.

    Science.gov (United States)

    Kawai, Kenji; Bando, Masayasu; Suzuki, Takahiro; Hayakawa, Kenji

    2004-04-01

    We experienced a case of intraocular lens (IOL) luxation with the capsular bag after vitrectomy. The case was a 66-year-old female in whom an IOL was implanted one year after surgery for giant tear retinal detachment using silicone oil. Four years after the implantation surgery, the patient suffered subluxation of the IOL with the capsular bag. Examinations of the luxated IOL with the capsular bag using a stereoscopic microscope confirmed the presence of silicone oil droplets between the capsule and the IOL. Adhesion of vitreous body residues was observed in the capsule. Luxation of the IOL was thought to be connected with chronic inflammation resulting from the use of silicone oil and repeated vitrectomy. In addition to examining pathological findings of luxated IOL, it would also be important in the future to identify the pathology of the capsular bag.

  6. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

  7. Biochemical Analysis of Synovial Fluid, Cerebrospinal Fluid and Vitreous Humor at Early Postmortem Intervals in Donkeys

    Directory of Open Access Journals (Sweden)

    Doha Yahia

    2014-01-01

    Full Text Available Biochemical analysis of body fluids after death is a helpful tool in veterinary forensic medicine. Synovial fluid, cerebrospinal fluid (CSF and vitreous humor are easily accessible and well preserved from contamination. Five donkeys (Equus africanus asinus aged 1 - 2 years old were subjected to the study. Samples (Synovial fluid, CSF and vitreous humor were collected before death (antimortem and then at 2, 4, 6, 8, 10 and 12 hours postmortem. Samples were analyzed for glucose, chloride, sodium, magnesium, potassium, enzymes and total protein. Synovial fluid analysis showed that glucose concentration started to decrease at 6 hours postmortem, while magnesium level increased with time. Other parameters were more stable. CSF analysis showed several changes related to time after death as the decrease in glucose and sodium levels, and the increased levels of potassium, magnesium, calcium and total protein. Vitreous analysis revealed a reduction in glucose level and increased potassium and magnesium concentrations. The present study concluded that biochemical analysis of synovial fluid, vitreous humor and CSF can help in determination of time since death in donkeys. This study recommend using CSF for determination of early post-mortem intervals.

  8. Raman spectroscopy characterization of diabetes effects on human vitreous in diabetic retinopathy

    Science.gov (United States)

    Sebag, Jerry; Nie, Shuming; Reiser, Karen M.; Yu, Nai-Teng

    1993-06-01

    Nonenzymatic glycation alters collagen throughout the body, resulting in the histopathology that underlies diabetic disease in several organs. In the eye such changes in vitreous collagen could contribute to the progression of proliferative diabetic retinopathy by inducing vitreous degeneration. In this study, near infrared Fourier-transform Raman spectroscopy was performed on vitreous obtained at surgery from diabetic patients and from non-diabetic control subjects. The findings were compared to measurements obtained in untreated and glycated (in vitro) rat-tail tendon collagen, as well as demineralized chick bone, rich in crosslinks. The results demonstrated substantial changes in diabetic vitreous collagen not resulting from enzyme-mediated crosslinking, but most likely advanced nonenzymatic glycation. This approach appears to be useful as a means of characterizing the molecular changes induced by diabetes. Furthermore, this technique could be developed as a way of quantifying these changes in vivo in several tissues, so as to gauge the severity of disease and monitor the response to therapy.

  9. Vitreous veils and radial lattice in Marshall syndrome.

    Science.gov (United States)

    Brubaker, Jacob W; Mohney, Brian G; Pulido, Jose S; Babovic-Vuksanovic, Dusica

    2008-12-01

    To report the findings of membranous vitreous veils and radial lattice in a child with Marshall syndrome. Observational case report. Retrospective review of medical records and fundus photograph of a 6-year-old boy with Marshall syndrome. Vitreoretinal findings were significant for bilateral membranous vitreous veils and radial lattice degeneration. This case demonstrates the occurrence of vitreous veils and radial lattice degeneration in patients with Marshall syndrome.

  10. Acquired Nonpigmented Vitreous Cyst Associated With Lattice Degeneration.

    Science.gov (United States)

    Lu, Jing; Mai, Guiying; Liu, Ruyuan; Luo, Yan; Lu, Lin

    2017-10-01

    A 63-year-old male presented with a round-shaped floater and visual obscuration in the right eye. Clinical evaluation showed a nonpigmented vitreous cyst connected to a lattice degeneration by a stalk. Immunostaining of the vitreous cyst obtained from vitrectomy showed its origin of retinal neuroepithelium. The cyst was formed by continuous vitreous traction, which might tear up the disrupted retina at the area of lattice degeneration. This report added the lattice degeneration to the list of causes for the acquired vitreous cyst. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:856-858.]. Copyright 2017, SLACK Incorporated.

  11. Diabetes-induced oxidative stress in the vitreous humor

    Directory of Open Access Journals (Sweden)

    Zsuzsanna Géhl

    2016-10-01

    Conclusion: The study demonstrates that diabetes-associated redox alterations also reach the vitreous with the most prominent changes being increased protein carbonylation and increased antioxidant levels.

  12. Lens stem cells may reside outside the lens capsule: an hypothesis

    Directory of Open Access Journals (Sweden)

    Meyer Rita A

    2007-06-01

    Full Text Available Abstract In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors. Historically, the lens has been viewed as a closed system, in which cells at the periphery of the lens epithelium differentiate into fiber cells. Theoretical considerations led us to question whether the intracapsular lens is indeed self-contained. Since stem cells generate tumors and the lens does not naturally develop tumors, we reasoned that lens stem cells may not be present within the capsule. We hypothesize that lens stem cells reside outside the lens capsule, in the nearby ciliary body. Our ideas challenge the existing lens biology paradigm. We begin our discussion with lens background information, in order to describe our lens stem cell hypothesis in the context of published data. Then we present the ciliary body as a possible source for lens stem cells, and conclude by comparing the ocular lens with the corneal epithelium.

  13. Thermodynamic Origin of the Vitreous Transition

    Directory of Open Access Journals (Sweden)

    Robert Tournier F.

    2011-05-01

    Full Text Available The vitreous transition is characterized by a freezing of atomic degrees of freedom at a temperature Tg depending on the heating and cooling rates. A kinetic origin is generally attributed to this phenomenon instead of a thermodynamic one which we develop here. Completed homogeneous nucleation laws reflecting the energy saving due to Fermi energy equalization of nascent crystals and their melt are used. They are applied to bulk metallic glasses and extended to inorganic glasses and polymers. A transition T*g among various Tg corresponds to a crystal homogeneous nucleation temperature, leading to a preliminary formation of a cluster distribution during the relaxation time preceding the long steady-state nucleation time of crystals in small samples. The thermally-activated energy barrier ΔG*2ls/kBT at T*g for homogeneous nucleation is nearly the same in all glass-forming melts and determined by similar values of viscosity and a thermally-activated diffusion barrier from melt to cluster. The glass transition T*g is a material constant and a linear function of the energy saving associated with charge transfers from nascent clusters to the melt. The vitreous transition and the melting temperatures alone are used to predict the free-volume disappearance temperature equal to the Vogel-Fulcher-Tammann temperature of fragile glass-forming melts, in agreement with many viscosity measurements. The reversible thermodynamic vitreous transition is determined by the disappearance temperature T*g of the fully-relaxed enthalpy Hr that is not time dependent; the observed specific heat jump at T*g is equal to the proportionality coefficient of Hr with (T*g − Ta for T ≤ T*g as expected from the enthalpy excess stored by a quenched undercooled melt at the annealing temperature Ta and relaxed towards an equilibrium vitreous state. However, the heat flux measurements found in literature over the last 50 years only gave an out-of-equilibrium Tg since the enthalpy

  14. Late onset retinoblastoma presenting with vitreous haemorrhage

    DEFF Research Database (Denmark)

    Bagger, Mette; Prause, Jan Ulrik; Heegard, Steffen

    2012-01-01

    in the retina. A vascularized gelatinous mass was revealed after vitrectomy. Later the patient developed white cysts in the anterior chamber and histological findings were indicative of a retinoblastoma. The patient was enucleated and the diagnosis of retinoblastoma was confirmed. Intraocular surgery in young...... people with unknown retinoblastoma enhances the risk of metastasis development, orbital recurrence and death. Unexplained vitreous haemorrhage can obscure the view of a tumour but ultrasonic findings of a retinal mass calls for further imaging e.g. through MRI. The case illustrates the importance...

  15. Mechanical Models of the Dynamics of Vitreous Substitutes

    Directory of Open Access Journals (Sweden)

    Krystyna Isakova

    2014-01-01

    Full Text Available We discuss some aspects of the fluid dynamics of vitreous substitutes in the vitreous chamber, focussing on the flow induced by rotations of the eye bulb. We use simple, yet not trivial, theoretical models to highlight mechanical concepts that are relevant to understand the dynamics of vitreous substitutes and also to identify ideal properties for vitreous replacement fluids. We first recall results by previous authors, showing that the maximum shear stress on the retina grows with increasing viscosity of the fluid up to a saturation value. We then investigate how the wall shear stress changes if a thin layer of aqueous humour is present in the vitreous chamber, separating the retina from the vitreous replacement fluid. The theoretical predictions show that the existence of a thin layer of aqueous is sufficient to substantially decrease the shear stress on the retina. We finally discuss a theoretical model that predicts the stability conditions of the interface between the aqueous and a vitreous substitute. We discuss the implications of this model to understand the mechanisms leading to the formation of emulsion in the vitreous chamber, showing that instability of the interface is possible in a range of parameters relevant for the human eye.

  16. SHORT REPORT SHO SHO Persistent hyperplastic primary vitreous ...

    African Journals Online (AJOL)

    The overall shape of PHPV has been likened to a martini glass. The globe is usually small, with the vitreous typically abnormally hyper- intense on both T1 and T2-weighted sequences. The signal intensity of layered haemorrhage in vitreous can vary with the age of blood (Fig. 1). Retinal detachment (RD). Separation of the ...

  17. 21 CFR 886.4150 - Vitreous aspiration and cutting instrument.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vitreous aspiration and cutting instrument. 886.4150 Section 886.4150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cutting instrument. (a) Identification. A vitreous aspiration and cutting instrument is an electrically...

  18. Vitreous mediators in retinal hypoxic diseases.

    Science.gov (United States)

    dell'Omo, Roberto; Semeraro, Francesco; Bamonte, Giulio; Cifariello, Francesco; Romano, Mario R; Costagliola, Ciro

    2013-01-01

    The causes of retinal hypoxia are many and varied. Under hypoxic conditions, a variety of soluble factors are secreted into the vitreous cavity including growth factors, cytokines, and chemokines. Cytokines, which usually serve as signals between neighboring cells, are involved in essentially every important biological process, including cell proliferation, inflammation, immunity, migration, fibrosis, tissue repair, and angiogenesis. Cytokines and chemokines are multifunctional mediators that can direct the recruitment of leukocytes to sites of inflammation, promote the process, enhance immune responses, and promote stem cell survival, development, and homeostasis. The modern particle-based flow cytometric analysis is more direct, stable and sensitive than the colorimetric readout of the conventional ELISA but, similar to ELISA, is influenced by vitreous hemorrhage, disruption of the blood-retina barrier, and high serum levels of a specific protein. Finding patterns in the expression of inflammatory cytokines specific to a particular disease can substantially contribute to the understanding of its basic mechanism and to the development of a targeted therapy.

  19. Vitreous Mediators in Retinal Hypoxic Diseases

    Directory of Open Access Journals (Sweden)

    Roberto dell'Omo

    2013-01-01

    Full Text Available The causes of retinal hypoxia are many and varied. Under hypoxic conditions, a variety of soluble factors are secreted into the vitreous cavity including growth factors, cytokines, and chemokines. Cytokines, which usually serve as signals between neighboring cells, are involved in essentially every important biological process, including cell proliferation, inflammation, immunity, migration, fibrosis, tissue repair, and angiogenesis. Cytokines and chemokines are multifunctional mediators that can direct the recruitment of leukocytes to sites of inflammation, promote the process, enhance immune responses, and promote stem cell survival, development, and homeostasis. The modern particle-based flow cytometric analysis is more direct, stable and sensitive than the colorimetric readout of the conventional ELISA but, similar to ELISA, is influenced by vitreous hemorrhage, disruption of the blood-retina barrier, and high serum levels of a specific protein. Finding patterns in the expression of inflammatory cytokines specific to a particular disease can substantially contribute to the understanding of its basic mechanism and to the development of a targeted therapy.

  20. Persistent hyperplastic primary vitreous: imaging evaluation

    International Nuclear Information System (INIS)

    Jacob, Beatriz Mahmud; Teixeira, Kim-Ir-Sen Santos; Figueiredo, Sizenildo da Silva; Nobrega, Bruno Barcelos da

    2003-01-01

    Persistent hyperplastic primary vitreous (PHPV) is a congenital developmental anomaly of the eye that primarily affects premature infants. PHPV results from failure of regression of the embryogenic primary vitreous and hyaloid vasculature, and proliferation of connective tissue. Three types of PHPV may be found: anterior, posterior and a combination of anterior and posterior. The clinical findings include leukocoria (white pupillary reflex) and microphthalmic eye. This anomaly is usually unilateral and unassociated with other systemic findings. The differential diagnosis between PHPV and other ocular diseases may be difficult due to similar features such as leukocoria, detached retina, retinal folds and cataract. Other diseases with similar features include retinoblastoma, isolated congenital cataract, retinopathy of prematurity and pseudo gliomas or leukocorias. Direct visualization of the remnants of the fetal hyaloid vascular system offers the best evidence of PHPV. However, diagnosis using the ophthalmoscope is sometimes impossible because of opaque tissues. In this circumstance an indirect visualization by ultrasound, computed tomography or magnetic resonance imaging may be useful. These imaging methods provide valuable information for the differentiation from other diseases, particularly retinoblastoma. The authors present a review of the literature and an iconographic study of the imaging findings in patients with PHPV. (author)

  1. Twenty-four hour intraocular pressure monitoring with the SENSIMED Triggerfish contact lens: effect of body posture during sleep.

    Science.gov (United States)

    Beltran-Agulló, Laura; Buys, Yvonne M; Jahan, Farzana; Shapiro, Colin M; Flanagan, John G; Cheng, Jason; Trope, Graham E

    2017-10-01

    To determine the difference in relative intraocular pressure (IOP) measured by the SENSIMED Triggerfish (TF) contact lens in flat compared with 30° head-up sleeping positions in patients with progressive primary open-angle glaucoma or normotensive glaucoma, based on recent or recurrent disc haemorrhage. Prospective, randomised, cross-over, open-label comparative study. IOP was monitored for 24 hours using TF on two separate sessions. Patients were randomly assigned to sleep flat one night and 30° head-up the other. Outputs in arbitrary units were obtained. Sleep and wake periods were defined as 22:00-6:00 and 8:00-22:00, respectively. Mean TF values during sleep and wake periods and wake-sleep and sleep-wake slopes were calculated for each session. TF output signals were compared between positions. Twelve subjects completed the study. Significant mean positive slopes were noted during the sleep period for both positions (pSleep position affects IOP as measured by TF in some patients with progressive glaucoma. The upward drift in TF output detected in >50% of the subjects requires further investigation to establish whether the increased output values over time are an artefact induced by the TF or a real change in IOP. NCT01351779. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  2. Toxic effects of extracellular histones and their neutralization by vitreous in retinal detachment.

    Science.gov (United States)

    Kawano, Hiroki; Ito, Takashi; Yamada, Shingo; Hashiguchi, Teruto; Maruyama, Ikuro; Hisatomi, Toshio; Nakamura, Makoto; Sakamoto, Taiji

    2014-05-01

    Histones are DNA-binding proteins and are involved in chromatin remodeling and regulation of gene expression. Histones can be released after tissue injuries, and the extracellular histones cause cellular damage and organ dysfunction. Regardless of their clinical significance, the role and relevance of histones in ocular diseases are unknown. We studied the role of histones in eyes with retinal detachment (RD). Vitreous samples were collected during vitrectomy, and the concentration of histone H3 was measured by enzyme-linked immunosorbent assay. The location of the histones and related molecules was examined in a rat RD model. The release of histones and their effects on rat retinal progenitor cells R28 and ARPE-19 were evaluated in vitro. In addition, the protective role of the vitreous body against histones was tested. The intravitreal concentration of histones was higher in eyes with RD (mean, 30.9 ± 9.8 ng/ml) than in control eyes (below the limit of detection, Phistone H3 was observed on the outer side of the detached retina and was associated with photoreceptor death. Histone H3 was released from cultured R28 by oxidative stress. Histones at a concentration 10 μg/ml induced the production of interleukin-8 in ARPE-19 cells (2.5-fold increase, PHistones were toxic to cells at concentrations of ≥ 20 μg/ml. Vitreous body or hyaluronan decreased toxicity of histones by inhibiting diffusion of histones. These results indicate that histones are released from retinas with RD and may modulate the subretinal microenvironment by functioning as damage-associated molecular pattern molecules, thereby inducing proinflammatory cytokines or cell toxicity. In addition, the important role of the vitreous body and hyaluronan in protecting the retina from these toxic effects is suggested.

  3. Cryo-electron microscopy of vitreous sections

    International Nuclear Information System (INIS)

    Dubochet, J.; Al-Amoudi, A.; McDowall, A.W.

    2002-01-01

    Full text: For the last two decades, cryo-electron microscopy (cryo-em) of thin layers of vitrified biological suspensions has considerably extended applications in electron microscopy. Biomacromolecules or their assemblies can be observed in their fully hydrated native state, without any or few microscopy related preparation artefacts. Only electron beam damage still limits resolution, thus leaving room for specialists of image processing, capable of extracting the very last bit of information created by a limited number of electrons. They're skills and programs have been very good when applied to thin specimens but this method does not apply readily to bulk specimens. However over the last 20 years, cryo-em of vitreous bulk material and sections has also been under development. In principle, it is the dream method of structural cell biology. It consists in vitrifying a sample of tissue by rapid cooling, cutting into ultra-thin sections and cryo-em observation with all details perfectly preserved. Practically the technical problems are considerable. First of all, vitrification, which is relatively easy for sub-micron sample, must be extended to macroscopic dimensions. For this purpose, freezing under high pressure has proved very effective. Cutting a piece of vitreous material into u nder the knife . A compromise must be found between fracturing the brittle material or plastic deformation when it is more viscous. Here the recent development of an oscillating knife is promising. Finally, to become fluent with the various manipulations and adjustments leading to optimal observations requires time and experience. Copyright (2002) Australian Society for Electron Microscopy Inc

  4. Instantaneous flow rate of vitreous cutter probes.

    Science.gov (United States)

    Rossi, Tommaso; Querzoli, Giorgio; Angelini, Giampiero; Rossi, Alessandro; Malvasi, Carlo; Iossa, Mario; Ripandelli, Guido

    2014-11-20

    We report on instantaneous volumetric flow rate of vitreous cutters measured by means of particle image velocimetry (PIV). In an in vitro experimental study, vitreous cutters mounting a regular blade (RB) or modified Twedge blade (TB) engineered for higher flow were connected to a console machine equipped with a double peristaltic and Venturi pump, and immersed in balanced salt solution (BSS). Instantaneous flow was measured on aspiration tubing sections proximal to the cutter hand piece. Measures settings were as follows: (1) regular functioning at 3000 and 6000 cuts per minute (cpm) with 300 mm Hg aspiration with both pumps, (2) aspiration tubing clamped proximal to pump cassette, and (3) aspiration tubing clamped proximal to hand piece, and (4) flow fluctuation as a function of cut rate also was calculated. For main outcome measures, instantaneous volumetric flow rate in mL/min and flow fluctuation measured as the standard deviation of flow rate were measured. Regular functioning shows sinusoidal flow oscillating at cut rate frequency, with amplitude between ±50 mL/min at 3000 cpm and ±35 mL/min at 6000 cpm. The TB always determined a bimodal wave and neither blade nor pump type influenced the sinusoidal pattern of flow. Clamping aspiration tubing zeroes flow, but does not influence fluctuation frequency or amplitude. Clamping at the hand piece determined a significantly higher oscillation. Oscillation amplitude retain a typical resonance pattern with significant changes in function of cut rate and resonance occurs at approximately 4000 cpm. Cutter blade action determines instantaneous flow rate fluctuation that interferes significantly with cutter suction and hampers a steady suction through cutter port. In a surgical scenario, this translates into a higher risk of inadvertent retinal entrapment and lower predictability of cutter behavior, especially at frequency approaching resonance. Copyright 2014 The Association for Research in Vision and Ophthalmology

  5. "Vitreous loss: Incidence and complications in extracapsular Cataract extractions "

    Directory of Open Access Journals (Sweden)

    Nikeghbali A

    2000-09-01

    Full Text Available One of the dangerous complications of cataract extractions is vitreous loss. The purpose of this stuy is to evaluate the incidence of vitreous loss and its sepuale while teaching residents at Rasoul Akram Hospital in Iran. This study has been conducted on existing records of 730 eyes which were subjectd to extracapsular cataract extractions by 3rd and 4th year, right handed resident of Rasoul Akram hospital. The information was taken from the records of patients who had vitreous loss during cataract surgery and the following data was extracted. The presence of any systemic diseases, phase of operation where vitreous loss occurred, vision on the next day, one month and 3 months later, the cause of low vision and any post operative sequale of the eye were evaluated. Extracted data collected and the prevalence of vitreous loss and its sequale were indentified and presented. Forty-nine eyes (6.7% had vitreous loss, thirty-one of them were in the left eye (63.3% and eighteen of them were in the right eye (36.7%. Regarding the stage of operation in which vitrous loss had occurred: twenty –eight eyes while nucleous delivery (57.7% eighteen eyes during aspiration of cortical material (36.7% and in three cases during IOL implantation. Five eyes had pseudoexfoliaton syndrome, four patients were diabetic and three had high myopia. Post operational sequale of these 49 eyes were: thirty-five with transient corneal edema (71.4%. Nine with misshaped pupils (18.9%, four with high astigmatism (8.1%, tow with cystoid macular edema (4%, two with retinal detachment (4% and seven with cloudy vitreous. (14.3%. The incidence of vitreous loss is more than expected. More extensive research to evaluated the prognositc factors according to the eye (OD/OS and the stage of the operation the leads to vitreous loss and to decrease its incidence is still needed.

  6. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory...

  7. Unilateral persistent hyperplastic primary vitreous: intensive management approach with excellent outcome beyond visual maturation.

    Science.gov (United States)

    Yusuf, Imran H; Patel, Chetan Kantibhai; Salmon, John F

    2015-01-06

    Persistent hyperplastic primary vitreous (PHPV) is an ocular developmental disorder resulting from incomplete apoptosis of the embryonic hyaloid vasculature. Unilateral PHPV is traditionally associated with a poor prognosis because of the challenges associated with managing progressive anisometropic amblyopia. We report a child with unilateral PHPV who underwent cataract extraction, primary posterior capsulotomy with anterior vitrectomy and intraocular lens implantation followed by combined trabeculectomy/trabeculotomy within the first 8 weeks of life. Intensive optometric and orthoptic input was required for many years to manage the increasing anisometropic amblyopia with final visual acuity of 20/40 unaided in the affected eye and without evidence of glaucomatous optic neuropathy. This case illustrates the excellent visual outcome possible in a child with complex, unilateral PHPV using an intensive management approach comprising: early surgical intervention for congenital cataract and secondary glaucoma, meticulous monitoring of refraction, visual acuity and intraocular pressure and motivated parents who engaged in the management. 2015 BMJ Publishing Group Ltd.

  8. Time course of development of posterior vitreous detachments after phacoemulsification surgery.

    Science.gov (United States)

    Hikichi, Taiichi

    2012-10-01

    To determine when posterior vitreous detachments (PVDs) develop after phacoemulsification and aspiration combined with foldable intraocular lens implantation. Prospective, consecutive case series. A total of 575 eyes without a PVD preoperatively were studied prospectively and followed for 3 years after uneventful phacoemulsification surgery. All patients underwent a comprehensive ocular examination, including a dynamic vitreous examination using biomicroscopy with and without a preset lens and a preoperative retinal examination on the day of surgery; the day postoperatively; 1 week and 1, 3, 6, and 12 months postoperatively; and every 6 months for 3 years postoperatively. The patients were divided into groups and analyzed on the basis of age and refractive error or axial length. The cumulative incidence rates of eyes that developed PVD for 3 years postoperatively at each postoperative time point. The cumulative numbers and percentages of eyes that developed a PVD were 6 (1.0%), 18 (3.1%), 31 (5.4%), 45 (7.8%), 63 (11.0%), 88 (15.3%), 106 (18.4%), 133 (23.1%), and 172 (30.0%) within 1 week and 1, 3, 6, 12, 18, 24, 30, and 36 months, respectively. Eleven (6.4%) of the 172 eyes in which a PVD developed during the follow-up period had new retinal breaks with or without a retinal detachment. Eight (15.4%) of 52 eyes with lattice degeneration and 3 (2.5%) of 120 eyes without lattice degeneration had retinal breaks associated with a PVD; these percentages were significant (P = 0.003). Development of PVDs seems to accelerate after phacoemulsification and linearly accumulated for 3 years postoperatively. Approximately 6% of eyes with a PVD had retinal breaks and eyes with lattice degeneration had a 6.2-fold higher risk of developing retinal breaks associated with a PVD. Long-term follow-up is needed after phacoemulsification is performed. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  9. Reticulated Vitreous Carbon Electrodes for Gas Phase Pulsed Corona Reactors

    National Research Council Canada - National Science Library

    Locke, B

    1998-01-01

    A new design for gas phase pulsed corona reactors incorporating reticulated vitreous carbon electrodes is demonstrated to be effective for the removal of nitrogen oxides from synthetic air mixtures...

  10. Reticulated Vitreous Carbon Electrodes for Gas Phase Pulsed Corona Reactors

    National Research Council Canada - National Science Library

    LOCKE, B

    1999-01-01

    A new design for gas phase pulsed corona reactors incorporating reticulated vitreous carbon electrodes is demonstrated to be effective for the removal of nitrogen oxides from synthetic air mixtures...

  11. Objective Measurement of Vitreous Inflammation using Optical Coherence Tomography

    Science.gov (United States)

    Keane, Pearse A.; Karampelas, Michael; Sim, Dawn A.; Sadda, Srinivas R.; Tufail, Adnan; Sen, H. Nida; Nussenblatt, Robert B.; Dick, Andrew D.; Lee, Richard W.; Murray, Philip I.; Pavesio, Carlos E.; Denniston, Alastair K.

    2014-01-01

    Purpose To obtain measurements of vitreous signal intensity from optical coherence tomography (OCT) image sets in patients with uveitis, with the aim of developing an objective, quantitative marker of inflammatory activity in patients with this disease. Design Retrospective, observational case-control series. Participants Thirty patients (30 eyes), with vitreous haze secondary to intermediate, posterior, or panuveitis; twelve patients (12 eyes) with uveitis but without evidence of vitreous haze; and 18 patients (18 eyes) without intraocular inflammation or vitreoretinal disease. Methods Clinical and demographic characteristics were recorded, including visual acuity (VA), diagnosis, and anatomic type of uveitis. In each eye, the anterior chamber (AC) was graded for cellular activity and flare according to standardized protocols. The presence and severity of vitreous haze was classified according to the National Eye Institute system. Spectral domain OCT images were analyzed using custom software. This software provided an “absolute” measurement of vitreous signal intensity, which was then compared to that of the retinal pigment epithelium (RPE), generating an optical density ratio with arbitrary units (“VIT/RPE-Relative Intensity”). Main Outcome Measures Correlation between clinical vitreous haze scores and OCT-derived measurements of vitreous signal intensity. Results VIT/RPE-Relative Intensity was significantly higher in uveitic eyes with known vitreous haze (0.150) than in uveitic eyes without haze or in healthy controls (0.0767, p=0.0001). VIT/RPE-Relative intensity showed a significant, positive correlation with clinical vitreous haze scores (r=0.566, p=0.0001). Other ocular characteristics significantly associated with VIT/RPE-Relative Intensity included VA (r=0.573, p=0.0001), AC cells (r=0.613, p=0.0001), AC flare (r=0.385, p=0.003). Measurement of VIT/RPE-Relative Intensity showed a good degree of inter-grader reproducibility (95% limits of agreement

  12. Vitreous Microparticle Shedding in Retinal Detachment: A Prospective Comparative Study.

    Science.gov (United States)

    Tumahai, Perle; Saas, Philippe; Ricouard, Fanny; Biichlé, Sabéha; Puyraveau, Marc; Laheurte, Caroline; Delbosc, Bernard; Saleh, Maher

    2016-01-01

    Microparticles (MPs) are membrane-derived vesicles measuring less than 1 μm in diameter. They are shed from nearly every activated or preapoptotic cell and may exhibit biologic activities in inflammation or apoptosis settings. The main purpose of this study was to determine whether MP shedding was higher in the vitreous of patients with retinal detachment (RD). This was a prospective, comparative study. Levels of vitreous MPs (including phosphatidylserine [PS]-expressing MPs, photoreceptor cell-derived MPs, and photoreceptor cell-derived MPs expressing PS) and soluble proinflammatory factors (i.e., monocyte chemoattractant protein-1, intercellular adhesion molecule-1, and IL-6) were analyzed by flow cytometry. Samples were obtained from 49 eyes undergoing RD surgery and 41 control eyes. Vitreous levels of all the MPs studied were significantly increased in the RD group. Vitreous MP levels were correlated with levels of at least one proinflammatory factor depending on MP subsets. Concerning clinical parameters, vitreous PS-expressing MP and PS-expressing photoreceptor cell-derived MP levels were higher depending on the duration of RD at surgery, the detached retina surface, and the macula status and were found more sensitive than proinflammatory factors only for the duration of RD at surgery. Vitreous concentrations of MPs (mainly derived from photoreceptor cells) are higher after rhegmatogenous RD and found to be correlated with soluble proinflammatory factors.

  13. Lens dislocation has a possible relationship with laser iridotomy

    Directory of Open Access Journals (Sweden)

    Mutoh T

    2012-12-01

    Full Text Available Tetsuya Mutoh,1,2 Kevin F Barrette,2 Yukihiro Matsumoto,1 Makoto Chikuda11Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya City, Saitama, Japan; 2Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USAAbstract: We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 months following laser iridotomy. All patients were male and two eyes were complicated with acute primary angle closure glaucoma preoperatively. Case 1 showed bilateral lens dislocation, while cases 2 and 3 involved unilateral lens dislocation. Cases 2 and 3 showed lenses completely dislocated into the vitreous cavity. All cases needed lens removal and scleral fixation of intraocular lenses. Final visual acuity was 1.2 in all cases. We suspect that laser iridotomy may induce localized zonular dialysis that results in progressive zonular weakness, leading to lens dislocation.Keywords: lens dislocation, laser iridotomy, primary angle closure glaucoma

  14. Comparison of lens oxidative damage induced by vitrectomy and/or hyperoxia in rabbits

    Directory of Open Access Journals (Sweden)

    Hong Yan

    2017-02-01

    Full Text Available AIM: To compare of lens oxidative damage induced by vitrectomy and/or hyperoxia in rabbit. METHODS: Sixteen New Zealand rabbits (2.4-2.5 kg were randomly divided into two groups (Group A, n=12; Group B, n=4. In Group A, the right eyes were treated with vitrectomy and systemic hyperoxia (oxygen concentration: 80%-85%, 1 ATA, 4h/d (Group A-right, and the left eyes were treated with hyperoxia without vitrectomy surgery (Group A-left. Four rabbits in group B (eight eyes were untreated as the controls. Lens transparency was monitored with a slit lamp and recorded before and after vitrectomy. After hyperoxic treatment for 6mo, the eyeballs were removed and the lens cortices (containing the capsules and nuclei were separated for further morphological and biochemical evaluation. RESULTS: Six months after treatments, there were no significant morphological changes in the lenses in any experimental group when observed with a slit lamp. However, the levels of water-soluble proteins and ascorbate, and the activities of catalase and Na+-K+-ATPase were significantly reduced, whereas the levels of malondialdehyde and transforming growth factor β2 (TGF-β2 were significantly elevated, in both the cortices and nuclei of eyes treated with vitrectomy and hyperoxia. The increase in protein-glutathione mixed disulfides and the reduction in water-soluble proteins were more obvious in the lens nuclei. The levels of ascorbate in the vitreous fluid were also reduced after vitrectomy, whereas TGF-β2 increased after vitrectomy and hyperoxia. Systemic hyperoxia exposure increased these effects. CONCLUSION: Removal of the intact vitreous gel with vitrectomy and exposing the lens to increased oxygen from the retina induce lens oxidation and aggregation. Thus, an intact vitreous gel structure may protect the lens from oxidative insult and maintain lens transparency.

  15. Clinical research on the development of posterior vitreous detachments after coaxial microincision phacoemulsification

    Directory of Open Access Journals (Sweden)

    Rong Xu

    2013-09-01

    Full Text Available AIM: To explore the development process of when posterior vitreous detachments(PVDsafter coaxial micro-incision phacoemulsification and aspiration combined with foldable intraocular lens implantation.METHODS: Clinical data of 917 patients with cataract were collected after coaxial microincision phacoemulsification and aspiration combined with foldable intraocular lens implantation. The 917 operating eyes forms observation group and the 917 corresponding normal eyes serve as control group. All patients underwent a comprehensive ocular examination before surgery. The vitreous and retinal condition was tested by B-scan ultrasonography and biomicroscope with a 90-diopter(Dpreset lens after 1 week and 1, 3, 6, and 12 months postoperatively. RESULTS: The incident rate of eyes in the observation group that developed PVD after operation were 8(0.9%, 31(3.4%, 53(5.8%, 78(8.5%, 129(14.1%within 1 week and 1, 3, 6, 12 months, respectively. Ten(7.8%of the 129 eyes in which PVD developed during the one year follow-up period had new retinal breaks with or without a retinal detachment; One(0.1%of the 788 eyes in which a PVD did not developed during the follow-up period had new retinal tear with or without a retinal detachment; these percentages were statistically significant(P=0.009. Eight(14.8%of 54 eyes with lattice degeneration and 2(2.7%of 75 eyes without lattice degeneration had retinal tears associated with a PVD; the difference was statistically significant(P=0.004.CONCLUSION: Development of PVDs seems to accelerate after coaxial microincision phacoemulsification and linearly accumulated for 1 year postoperatively. Approximately 7.8% of eyes with a PVD had retinal tears. Compared with patients having no lattice degeneration, Patients' eyes with lattice degeneration had a 5.5-fold higher risk of developing retinal breaks associated with a PVD. This indicates long-term follow-up is necessary after phacoemulsification is performed.

  16. Detection of Treponema pallidum in the vitreous by PCR

    Science.gov (United States)

    Müller, M; Ewert, I; Hansmann, F; Tiemann, C; Hagedorn, H J; Solbach, W; Roider, J; Nölle, B; Laqua, H; Hoerauf, H

    2007-01-01

    Background Ocular involvement of syphilis still poses a clinical challenge due to the chameleonic behaviour of the disease. As the serodiagnosis has significant limitations, the direct detection of Treponema pallidum (TP) in the vitreous represents a desirable diagnostic tool. Methods Real‐time polymerase chain reaction (PCR) for the detection of TP was applied in diagnostic vitrectomies of two patients with acute chorioretinitis. Qualitative verification of TP by real‐time PCR and melting point analysis according to a modified protocol was ruled out. Patients underwent complete ophthalmological examination with fundus photographs, fluorescein angiography, serological examination, antibiotic treatment and follow‐up. Results In two cases of acute chorioretinitis of unknown origin, real‐time PCR of vitreous specimens of both patients provided evidence of TP and was 100% specific. Initial diagnosis of presumed viral retinitis was ruled out by PCR of vitreous specimen. Patients were treated with systemic antibiotics and showed prompt improvement in visual function and resolution of fundus lesions. Conclusions With real‐time PCR, detection of TP in the vitreous was possible and delivered a sensitive, quick and inexpensive answer to a disease rather difficult to assess. In cases of acute chorioretinitis, the use of PCR‐based assays of vitreous specimens in the diagnostic evaluation of patients is advisable. Although syphilitic chorioretinitis is a rare disease, PCR should include search for TP, as diagnostic dilemmas prolong definitive treatment in a sight‐threatening disease. PMID:17108014

  17. Prevalence of posterior vitreous detachment in glaucoma patients and controls.

    Science.gov (United States)

    Schwab, Christoph; Glatz, Wilfried; Schmidt, Bernd; Lindner, Ewald; Oettl, Karl; Riedl, Regina; Wedrich, Andreas; Ivastinovic, Domagoj; Velikay-Parel, Michaela; Mossboeck, Georg

    2017-05-01

    To evaluate the impact of oxidative stress - present in glaucoma - on the vitreous. We therefore compare the presence of early and late stages of posterior vitreous detachment (PVD) between patients with glaucoma and controls. The vitreous state was evaluated by the combination of optical coherence tomography and ultrasound. The main outcome was the vitreous state classified into 'no PVD', 'initial PVD' and 'advanced PVD'. We evaluated the vitreous state in 48 patients with glaucoma (age: mean 66.5 ± 11.9 years; visual field deviation: mean 10.4 ± 6.8 dB) and compared the results with 101 previously investigated controls (age: mean 73.6 ± 9.3 years). After one-to-one matching on age and sex, ordinal logistic regression revealed that patients with glaucoma were significantly more likely to exhibit advanced PVD stages compared to non-glaucoma patients (OR 2.60, 95% confidence interval: 1.06-6.36, p = 0.037). Our results suggest that the presence or absence of PVD might be a valuable hint for diagnosing glaucoma - however, further research is needed to determine whether PVD can be used to supplement current glaucoma screening guidelines. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  18. Identification of vitreous proteins in retinopathy of prematurity.

    Science.gov (United States)

    Sugioka, Koji; Saito, Akio; Kusaka, Shunji; Kuniyoshi, Kazuki; Shimomura, Yoshikazu

    2017-07-01

    Retinopathy of prematurity (ROP) is a disorder of blood vessels in the retina developed in premature infants and the leading cause of the blindness in children. Proteomic analysis was performed to identify vitreous proteins specific to patients with ROP. Vitreous humor samples were obtained from three patients with ROP and two patients with congenital cataract, the latter included as a control group. The vitreous samples were separated by 2D-PAGE and the proteins running as definitive spots were identified by MALDI-TOF MS spectrometry. We identified 13 and 6 proteins in the vitreous from ROP and cataract patients, respectively. Albumin, transferrin, pigment epithelium-derived factor (PEDF) and transthyretin were found in both patient groups. In the samples from ROP patients, PEDF and transthyretin levels were lower than in those from cataract patients, and retinol binding protein 3 and prostaglandin D synthase were not detected. Of the 13 proteins, 9 proteins including α-2-macroglobulin, ceruloplasmin, α-fetoprotein, vitamin D-binding protein, α-1-antitrypsin, α-1-β-glycoprotein, hemopexin, apolipoprotein A-1 and A-lV were found in vitreous samples of only the ROP patients. PEDF has anti-angiogenic and neurotrophic functions. Whether PEDF is increased or decreased in diabetic retinopathy has been controversial but we observed lower PEDF in the ROP samples than in the controls. The proteins specific to or decreased in ROP, if confirmed in future studies, may provide clue to understanding its pathogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available Subspecialties Cataract/Anterior Segment Comprehensive Ophthalmology Cornea/External Disease Glaucoma Neuro-Ophthalmology/Orbit Pediatric Ophthalmology/Strabismus Ocular Pathology/Oncology Oculoplastics/Orbit Refractive Management/Intervention Retina/Vitreous Uveitis ...

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available Subspecialties Cataract/Anterior Segment Comprehensive Ophthalmology Cornea/External Disease Glaucoma Neuro-Ophthalmology/Orbit Pediatric Ophthalmology/Strabismus Ocular Pathology/Oncology Oculoplastics/Orbit Refractive Management/Intervention Retina/Vitreous Uveitis Focus On ...

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Intervention Retina/Vitreous Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy ...

  2. The vitreous state thermodynamics, structure, rheology, and crystallization

    CERN Document Server

    Gutzow, Ivan S

    2013-01-01

    This book summarizes the experimental evidence and modern classical and theoretical approaches in understanding the vitreous state, from structural problems, over equilibrium and non-equilibrium thermodynamics, to statistical physics. Glasses, and especially silicate glasses, are only the best known representatives of this particular physical state of matter. Other typical representatives include organic polymer glasses, and many other easily vitrifying organic and inorganic substances, technically important materials, amidst them vitreous water and vitrified aqueous solutions, and also many metallic alloy systems. Some of these systems only form glasses under particular conditions, e.g. through ultra-rapid cooling. This book describes the properties and the formation of both every-day technical glasses and especially of such more exotic forms of vitreous matter. It is a unique source of knowledge and new ideas for materials scientists, engineers and researchers working on condensed matter. The new edition e...

  3. Vitreous Substitutes: Old and New Materials in Vitreoretinal Surgery

    Directory of Open Access Journals (Sweden)

    Camilla Alovisi

    2017-01-01

    Full Text Available Recent developments in vitreoretinal surgery have increased the need for suitable vitreous substitutes. A successful substitute should maintain all the physical and biochemical properties of the original vitreous, be easy to manipulate, and be long lasting. Substitutes can be gaseous or liquid, both of which have associated advantages and disadvantages related to their physical properties and use. Furthermore, new surgical techniques with smaller vitreoretinal instruments have driven the use of more viscous substitutes. In this review, we analyze and discuss the most frequently used vitreous substitutes and look ahead to future alternatives. We classify these compounds based on their composition and structure, discuss their clinical use with respect to their associated advantages and disadvantages, and analyze how new vitreoretinal surgical techniques have modified their use.

  4. Vitreous Substitutes: Old and New Materials in Vitreoretinal Surgery

    Science.gov (United States)

    Panico, Claudio; Eandi, Chiara M.

    2017-01-01

    Recent developments in vitreoretinal surgery have increased the need for suitable vitreous substitutes. A successful substitute should maintain all the physical and biochemical properties of the original vitreous, be easy to manipulate, and be long lasting. Substitutes can be gaseous or liquid, both of which have associated advantages and disadvantages related to their physical properties and use. Furthermore, new surgical techniques with smaller vitreoretinal instruments have driven the use of more viscous substitutes. In this review, we analyze and discuss the most frequently used vitreous substitutes and look ahead to future alternatives. We classify these compounds based on their composition and structure, discuss their clinical use with respect to their associated advantages and disadvantages, and analyze how new vitreoretinal surgical techniques have modified their use. PMID:28785482

  5. Efficacy observation of danshen injection iontophoresis treatment for vitreous hemorrhage

    Directory of Open Access Journals (Sweden)

    Jing Hao

    2013-11-01

    Full Text Available AIM: To probe into the clinical value of danshen injection iontophoresis in treatment of vitreous hemorrhage. METHODS: Eighty-eight vitreous hemorrhage patients(88 eyeswere selected from June 2012 to June 2013 in our hospital. The patients were divided into observation group and control group randomly, with 44 cases(44 eyesin each group. The patients in control group were treated with xueshuantong clinical drug treatment. The patients in observation group were treated with danshen injection iontophoresis clinical drug treatment. The clinical treatment and visual recovery situations of the patients in two groups were compared and analyzed. RESULTS: The cure rate and total effective rate of observation group were 75% and 95%. The cure rate and total effective rate of control group were 59% and 77%. There were statistically significant differences(PPCONCLUSION: Danshen injection iontophoresis therapy has positive role in improving clinical outcomes and promoting visual function for patients with vitreous hemorrhage.

  6. Survey: technique of performing intravitreal injection among members of the Brazilian Retina and Vitreous Society (SBRV

    Directory of Open Access Journals (Sweden)

    Helio F. Shiroma

    2015-02-01

    Full Text Available Purpose: To evaluate and describe the precautions involved in the technique of intravitreal injection of antiangiogenic drugs adopted by the ophthalmologists who are members of the Brazilian Society of Retina and Vitreous (SBRV. Methods: A questionnaire containing 22 questions related to precautions taken before, during, and after intravitreal injection was sent electronically to 920 members of SBRV between November 15, 2013 and April 31, 2014. Results: 352 responses (38% were obtained. There was a predominance of men (76% from the southwest region of Brazil (51%. The professional experience varied between 6 and 15 years after medical specialization (50%. Most professionals (76% performed an average of 1 to 10 intravitreal injections a week, and 88% of the procedures were performed in the operating room using povidone iodine (99%, sterile gloves, and blepharostat (94%. For inducing topical anesthesia, usage of anesthetic eye drops was the most used technique (65%. Ranibizumab (Lucentis® was the most common drug (55%, and age-related macular degeneration (AMD was the most treated disease (57%. Regarding the complications treated, 6% of the ophthalmologists had treated at least one case of retinal detachment, 20% had treated cases of endophthalmitis, 9% had treated cases of vitreous hemorrhage, and 12% had encountered cases of crystalline lens touch. Conclusion: Intravitreal injection is a procedure routinely performed by retina specialists and has a low incidence of complications. Performing the procedure in the operating room using an aseptic technique was preferred by most of the respondents. Ranibizumab was the most used drug, and AMD was the most treated disease.

  7. Role of avastin on the incidence of post-operative vitreous hemorrhage after vitrectomy in diabetic vitreous hemorrhage

    International Nuclear Information System (INIS)

    Ahmed, N.; Shaheer, M.; Tahir, M.Y.

    2014-01-01

    Diabetic retinopathy is one of the most common cause of legal blindness. Five to 10% of diabetic patients suffer from the proliferative diabetic retinopathy which includes the formation of new vessels on the retina and optic disc which can be complicated as vitreous hemorrhage and tractional retinal detachment. Pars plana vitrectomy along with laser photocoagulation is being used for the management of vitreous hemorrhage. In our study we used injection avastin one week before surgery to see its role on the incidence of rebleed after vitrectomy in diabetic vitreous hemorrhage. Materials and Methods; Fifty patients were divided into 2 equal groups on the basis of simple random sampling. 25 patients in Group I were operated with routine pars plana vitrectomy with endolaser photo- coagulation while in Group II all the 25 patients were given injection avastin intra-vitreally one week before surgery. Evaluation was done on the first post operative day, first follow up visit (one week) and after one month to see the incidence of re-bleed. Chi-square test was used for statistical analysis. Results: Fifty patients divided into two groups. In Group I, 3 patients had recurrent vitreous hemorrhage on first post-operative day, 3 patients had re-bleed on first follow up visit, and only 2 patients had re-bleed after one month. In Group II, none of the patients had recurrent vitreous hemorrhage on first post-operative day and on first follow-up visit (one week) while 2 patients had re-bleed after one month. Conclusion: Injection intravitreal Avastin (Bevaci- zumab) one week before surgery significantly reduces the risk of vitreous hemorrhage after vitrectomy in diabetic patients. (author)

  8. Contact lens in keratoconus

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2013-01-01

    Full Text Available Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP lenses, soft and soft toric lenses, piggy back contact lenses (PBCL, hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

  9. Contact lens in keratoconus

    Science.gov (United States)

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL. PMID:23925325

  10. Persistent hyperplastic primary vitreous – The martini glass sign

    African Journals Online (AJOL)

    2014-06-20

    /radiographics.14.5.7991814. 2. Küker W, Ramaekers V. Persistent hyperplastic primary vitreous: MRI. Neuroradiology. 1999;41(7):520–522. PMID: 10450848. http:// · dx.doi.org/10.1007/s002340050796. 3. Sun MH, Kao LY, ...

  11. Enzymatic Breakdown of Type II Collagen in the Human Vitreous

    NARCIS (Netherlands)

    van Deemter, Marielle; Pas, Hendri H.; Kuijer, Roel; van der Worp, Roelofje J.; Hooymans, Johanna M. M.; Los, Leonoor I.

    2009-01-01

    PURPOSE. To investigate whether enzymatic collagen breakdown is an active process in the human vitreous. METHODS. Human donor eyes were used for immunohistochemistry to detect the possible presence of the matrix metalloproteinase (MMP)-induced type II collagen breakdown product col2-3/4C-short in

  12. Posterior Vitreous Detachment and Retinal Detachment After Implantation of the Visian Phakic Implantable Collamer Lens

    OpenAIRE

    Bamashmus, Mahfouth A.; Al-Salahim, Seddique A.; Tarish, Nabil A.; Saleh, Mahmoud F.; Mahmoud, Hatem A.; Elanwar, Mohamed F.; Awadalla, Mohamed A.

    2013-01-01

    Introduction: To evaluate the vitreoretinal complications in myopes after Visian implantable collamer lenses (ICL) implantation. Materials and Methods: This is a retrospective, observational, non-comparative clinical study that evaluated 617 consecutive myopes who underwent ICL implantation at the Department of Refractive Surgery, Yemen Magrabi Hospital, Sana′a, Yemen between July 2006 and May 2010. Follow up ranged from 6 months to 40 months. Preoperative and postoperative patient evalua...

  13. Posterior vitreous detachment and retinal detachment after implantation of the Visian phakic implantable collamer lens.

    Science.gov (United States)

    Bamashmus, Mahfouth A; Al-Salahim, Seddique A; Tarish, Nabil A; Saleh, Mahmoud F; Mahmoud, Hatem A; Elanwar, Mohamed F; Awadalla, Mohamed A

    2013-01-01

    To evaluate the vitreoretinal complications in myopes after Visian implantable collamer lenses (ICL) implantation. This is a retrospective, observational, non-comparative clinical study that evaluated 617 consecutive myopes who underwent ICL implantation at the Department of Refractive Surgery, Yemen Magrabi Hospital, Sana'a, Yemen between July 2006 and May 2010. Follow up ranged from 6 months to 40 months. Preoperative and postoperative patient evaluation included manifest and cycloplegic refractions, uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), slit-lamp biomicroscopy, intraocular pressure and dilated retinal examination. Investigations included corneal topography, central corneal thickness, anterior chamber depth and white to white diameter. Retinal diseases and complications were recorded and analyzed preoperatively and postoperatively. Preoperatively, 61 (9.9%) eyes had posterior segment pathology requiring prophylactic laser photocoagulation. One eye developed spontaneous rhegmatogenous retinal detachment (RRD), one eye developed traumatic retinal detachment and two eyes required laser treatment postoperatively. The overall retinal detachment rate post-ICL was 0.32%. Posterior segment complications are rare after ICL implantation but dilated vitreoretinal assessment is important before and after the procedure. Patients with suspicious retinal lesions need a comprehensive vitreoretinal evaluation by a retinal specialist. If a patient develops floaters or blurry vision he/she requires further assessment by a vitreoretinal specialist.

  14. A Flow Cytometric Analysis of Vitreous Inflammatory Cells in Patients with Proliferative Diabetic Retinopathy

    Directory of Open Access Journals (Sweden)

    Mojca Urbančič

    2013-01-01

    Full Text Available The purpose of this study was to investigate inflammatory cells in vitreous from patients with proliferative diabetic retinopathy (PDR using flow cytometric analysis. Twenty-eight patients with PDR requiring vitrectomy because of macular traction or tractional retinal detachment were enrolled in the study (n=28, and 6 patients with macular hole (MH formed the control group. Samples of vitreous and peripheral venous blood were obtained at the beginning of vitrectomy. T lymphocytes were found in vitreous from patients with PDR, and CD4/CD8 ratio was higher in vitreous (median 4.3 compared to blood (median 1.9; P=0.003. No B lymphocytes were detected in vitreous. The percentage of histiocytes/macrophages was significantly higher in vitreous (median 62.1 in comparison with blood (median 5.5; P<0.0001. No lymphocytes were detected in vitreous of the control group. There were more T lymphocytes in vitreous from patients with active PDR. No association between cells in the vitreous and visual acuity improvement after surgery was found. In conclusion, T lymphocytes are found in vitreous from patients with PDR and reflect the activity of PDR but do not seem to predict visual prognosis. Higher CD4/CD8 ratio in vitreous compared to blood from patients with PDR is consistent with local inflammatory response in PDR.

  15. Microstructural characterization and influence of manufacturing parameters on technological properties of vitreous ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Njoya, D. [Laboratoire de Physico-chimie des Materiaux Mineraux, Departement de Chimie Inorganique, Faculte des Sciences, Universite de Yaounde I, B.P. 812, Yaounde (Cameroon); Laboratoire de Physico-chimie des Materiaux et Environnement, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Hajjaji, M., E-mail: Hajjaji@ucam.ac.ma [Laboratoire de Physico-chimie des Materiaux et Environnement, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Bacaoui, A. [Laboratoire de Chimie Organique Appliquee, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Njopwouo, D. [Laboratoire de Physico-chimie des Materiaux Mineraux, Departement de Chimie Inorganique, Faculte des Sciences, Universite de Yaounde I, B.P. 812, Yaounde (Cameroon)

    2010-03-15

    Microstructure of vitreous ceramic samples manufactured from kaolinitic-clay and feldspars raw materials from Cameroon was investigated in the range 1150-1250 deg. C by X-ray diffraction and scanning electron microscopy and by measuring some technological properties. Moreover, the simultaneous influence of feldspars content, heating temperature and soaking time on water absorption and firing shrinkage was evaluated by adopting the response surface methodology (Doehlert matrix), using the New Efficient Methodology for Research using Optimal Design (NEMROD) software. The results show that a spinel phase, mullite, glassy phase and some amount of hematite were formed. However, the spinel phase and potassic feldspar, as compared to the sodic one, disappeared at moderate firing temperature and soaking time. Apparently, mullite developed from spinel phase, which is formed from the demixion of metakaolin. On the other hand, it is found that the effects of fluxing content and firing temperature on the measured properties were almost similar and more influent than soaking time. Antagonistic and synergetic interactions existed between the considered parameters, and their importance differed for the considered properties. By using this mathematical tool, suitable operating conditions for manufacturing vitreous bodies were determined.

  16. Distribution of fluorescein sodium and triamcinolone acetonide in the simulated liquefied and vitrectomized Vitreous Model with simulated eye movements.

    Science.gov (United States)

    Stein, Sandra; Bogdahn, Malte; Rosenbaum, Christoph; Weitschies, Werner; Seidlitz, Anne

    2017-11-15

    Intravitreal administration is the method of choice for drug delivery to the posterior segment of the eye with special emphasis on the vitreous body and its surrounding retinal vasculature. In order to gain a better understanding of the underlying distribution processes, an in vitro model simulating the vitreous body (Vitreous Model, VM) and a system simulating the impact of movement on the VM (Eye Movement System, EyeMoS) was previously developed. In the study reported here, these systems were modified in regard to a standardized injection procedure, the diversity of simulated eye movements, extended periods of investigation, the opportunity to simulate the state after vitrectomy and in considering the physiological temperature. Fluorescein sodium (FS) and triamcinolone acetonide (TA) were used as (model) drugs to examine the drug distribution within the VM. Vitrectomy was simulated by replacing half the volume of the polyacrylamide gel that was used as vitreous substitute with the clinically used Siluron® 5000 whereas for a simulated liquefaction half the volume of the gel was replaced by buffer. A simulated liquefaction caused a 12-fold faster distribution of FS compared to the simulated juvenile VM, which was most likely caused by convective forces and mass transfer. Also, the injection technique (injection into the gel or into the buffer compartment) influenced the resulting distribution pattern. Without any liquefaction, the previously described initial injection channel occurred with both (model) drugs and, in the case of TA, remained almost unchanged during the investigation period of 72h. Simulating vitrectomized eyes, TA did not spread uniformly, but either remained in the depot or strongly sedimented within the VM suggesting that a homogenous distribution of a TA suspension is highly unlikely in vitrectomized eyes. High variabilities were observed with ex vivo animal eyes, demonstrating the limited benefit of explanted tissues for such distribution

  17. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, ... Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume Contacts May Contain Chemicals Harmful to Eyes ...

  18. Vitreous carbon mask substrate for X-ray lithography

    Science.gov (United States)

    Aigeldinger, Georg [Livermore, CA; Skala, Dawn M [Fremont, CA; Griffiths, Stewart K [Livermore, CA; Talin, Albert Alec [Livermore, CA; Losey, Matthew W [Livermore, CA; Yang, Chu-Yeu Peter [Dublin, CA

    2009-10-27

    The present invention is directed to the use of vitreous carbon as a substrate material for providing masks for X-ray lithography. The new substrate also enables a small thickness of the mask absorber used to pattern the resist, and this enables improved mask accuracy. An alternative embodiment comprised the use of vitreous carbon as a LIGA substrate wherein the VC wafer blank is etched in a reactive ion plasma after which an X-ray resist is bonded. This surface treatment provides a surface enabling good adhesion of the X-ray photoresist and subsequent nucleation and adhesion of the electrodeposited metal for LIGA mold-making while the VC substrate practically eliminates secondary radiation effects that lead to delamination of the X-ray resist form the substrate, the loss of isolated resist features, and the formation of a resist layer adjacent to the substrate that is insoluble in the developer.

  19. Application of ultrasound in the diagnosis of posterior vitreous detachment

    Directory of Open Access Journals (Sweden)

    Hui-Wei Wang

    2013-12-01

    Full Text Available AIM: To investigate the utility of ultrasound in the diagnosis of posterior vitreous detachment(PVD. METHODS: From September 2011 to September 2012, 506 eyes of 305 cases(male 191, female 114of PVD patients in our hospital were checked and analyzed with ultrasound.RESULTS: Totally, 179 eyes were diagnosed as partial PVD, the proportion was 35.4%. And 327 eyes were diagnosed as complete PVD, the proportion was 64.6%. Among the 61 eyes(12.1%with a small amount of hemorrhage of vitreous humor,retinal breaks of 26 eyes(5.1%were founded. Given the photocoagulation nicely heal to the breaks and then recovered. CONCLUSION:Ultrasonography can accurately diagnose PVD. It has non-invasive,convenience, and other characteristics, and it is worthy of clinical popularization.

  20. A safe technique for in-the-bag intraocular lens implantation in pediatric cataract surgery.

    Science.gov (United States)

    Khokhar, Sudarshan; Sharma, Reetika; Patil, Bharat; Sinha, Gautam; Nayak, Bhagabat; Kinkhabwala, Ravish Akhilkumar

    2015-01-01

    To describe a safe technique for in-the-bag intraocular lens (IOL) implantation in pediatric cataract patients who undergo lens aspiration with primary posterior capsulorhexis and anterior vitrectomy. Sixty eyes of 45 consecutive patients with congenital/developmental cataract underwent lens aspiration with primary posterior continuous curvilinear capsulorhexis (PCCC) with anterior vitrectomy and in-the-bag IOL implantation using the described technique of IOL implantation using anterior capsule as support. All eyes had stable IOL at the end of surgery and none of the eyes had lens decentration/dislocation in posterior vitreous. Implantation of in-the-bag IOL is difficult in children who undergo primary PCCC with anterior vitrectomy. Our technique of implanting IOL by pushing it against the back surface of anterior capsule is a safe method and results in no complications related to faulty IOL implantation.

  1. Vitreous fluid quantification of opiates, cocaine, and benzoylecgonine: comparison of calibration curves in both blood and vitreous matrices with corresponding concentrations in blood.

    Science.gov (United States)

    Antonides, Heather M; Kiely, Elizabeth R; Marinetti, Laureen J

    2007-10-01

    Vitreous fluid specimens are often used in the Montgomery County Coroner's Office as a second matrix confirmation for both cocaine and opiate analyses. In this manuscript, calibration curves constructed for both vitreous and blood were used to quantify vitreous specimens to evaluate if any matrix effects occur when measuring vitreous specimens using a calibration curve in blood. Cases that screened positive by ELISA for cocaine metabolite and opiates were confirmed by solid-phase extraction. Gas chromatography with mass spectral detection in the positive electron impact mode was used for the detection and quantification of oxycodone, free morphine, codeine, 6-monoacetylmorphine, hydrocodone, cocaine, and benzoylecgonine. For interpretive purposes, no significant matrix effects were found in concentrations of vitreous specimens quantified with a calibration curve constructed in a blood matrix. After determining that vitreous fluid can be accurately measured with blood calibrators, a comparison was made between blood and vitreous concentrations for the above analytes. Concentration differences between blood and vitreous specimens for each drug are evaluated with selected case histories included.

  2. Effects of mechanical stress and vitreous samples in retinal pigment epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Eri, E-mail: eritakahashi@fc.kuh.kumamoto-u.ac.jp; Fukushima, Ayako; Haga, Akira; Inomata, Yasuya; Ito, Yasuhiro; Fukushima, Mikiko; Tanihara, Hidenobu

    2016-02-12

    In rhegmatogenous retinal detachment (RRD), scattered RPE cells from the basement membrane into the vitreous cavity undergo an epithelial mesenchymal transition (EMT) and form the intraocular fibrous membrane in response to vitreous fluid. We investigated whether exposure to vitreous samples was associated with EMT-associated signals and mesenchymal characters. Human vitreous samples were collected from patients with RRD, epiretinal membrane (ERM), or macular hole (MH). We evaluated the effects of vitreous on ARPE-19 cells in suspension cultures using poly 2-hydroxyethyl methacrylate-coated dishes and three-dimensional (3D) Matrigel cultures. We found that exposure to vitreous samples did not induce morphological changes or accelerate wound closure in monolayers. Several samples showed increased phosphorylation of Smad2 and nuclear translocation of nuclear factor-κB. Mechanical stress triggered an elevation of phosphorylation levels in Smad2. In addition, exposure to vitreous fluid increased the phosphorylation of p38 mitogen-activated protein kinase in cell suspension cultures after mechanical stress. Moreover, ARPE-19 cells showed a stellate invasive phenotype in 3D Matrigel cultures with vitreous samples. In this study, we demonstrated that mechanical stress and vitreous were associated with EMT-associated signals and invasive phenotypes in 3D cultures but not in monolayers. These results have important implications for the role of vitreous humor in the induction of EMT and intraocular fibrosis.

  3. Vitreous Seeds in Retinoblastoma: Clinicopathologic Classification and Correlation.

    Science.gov (United States)

    Amram, Alec L; Rico, Grecia; Kim, Jonathan W; Chintagumpala, Murali; Herzog, Cynthia E; Gombos, Dan S; Chévez-Barrios, Patricia

    2017-10-01

    A recent classification scheme for retinoblastoma vitreous seeds has shown promise in predicting treatment response. For the first time, we correlate this clinical classification scheme with its histopathologic features. Retrospective review. Enucleated eyes received at the pathology department of the Retinoblastoma Center of Houston from 2010 to 2015. Macroscopic photographs of the enucleated eyes of patients with retinoblastoma were analyzed to select those with vitreous seeds. Cases with adequate material for clinicopathologic correlation were selected for further analysis, and clinical photographs were reviewed. Routine histopathologic slides were reviewed and compared with the clinical and macroscopic photographs. Seeds were classified as type 1 ("dust"), type 2 ("sphere"), or type 3 ("cloud"). To confirm the presence of macrophages, CD68 immunohistochemical staining was used. Synaptophysin was used to stain retinoblastoma cells. To correlate clinical vitreous seed type with histopathologic features. A total of 14 eyes with adequate amounts of tumor seeds along with clinical and macroscopic photographic correlation were selected from a total of 138 eyes reviewed. Type 1 seeds consisted of individual viable tumor cells and scattered macrophages. Type 2 seeds consisted of 2 submorphologies: spheres with viable cells throughout and spheres with an outer rim of viable cells but necrotic cells centrally. Type 3 seeds were composed of more than 90% necrotic material admixed with few macrophages and viable cells at their outer rim. Untreated (8/14) and previously treated (6/14) eyes showed similar histopathologic features for each type of seeds. Treated eyes had more type 1 and 3 seeds. We provide the first histopathologic correlation of the clinical classification scheme for vitreous seeds in retinoblastoma. "Dust" is formed by scattered single cells alternating with macrophages. "Spheres" with translucent centers contain multiple layers of viable tumor cells that

  4. Investigating the micro-rheology of the vitreous humor using an optically trapped local probe

    Science.gov (United States)

    Watts, Fiona; Ean Tan, Lay; Wilson, Clive G.; Girkin, John M.; Tassieri, Manlio; Wright, Amanda J.

    2014-01-01

    We demonstrate that an optically trapped silica bead can be used as a local probe to measure the micro-rheology of the vitreous humor. The Brownian motion of the bead was observed using a fast camera and the micro-rheology determined by analysis of the time-dependent mean-square displacement of the bead. We observed regions of the vitreous that showed different degrees of viscoelasticity, along with the homogeneous and inhomogeneous nature of different regions. The motivation behind this study is to understand the vitreous structure, in particular changes due to aging, allowing more confident prediction of pharmaceutical drug behavior and delivery within the vitreous humor.

  5. Investigating the micro-rheology of the vitreous humor using an optically trapped local probe

    International Nuclear Information System (INIS)

    Watts, Fiona; Wright, Amanda J; Tan, Lay Ean; Wilson, Clive G; Girkin, John M; Tassieri, Manlio

    2014-01-01

    We demonstrate that an optically trapped silica bead can be used as a local probe to measure the micro-rheology of the vitreous humor. The Brownian motion of the bead was observed using a fast camera and the micro-rheology determined by analysis of the time-dependent mean-square displacement of the bead. We observed regions of the vitreous that showed different degrees of viscoelasticity, along with the homogeneous and inhomogeneous nature of different regions. The motivation behind this study is to understand the vitreous structure, in particular changes due to aging, allowing more confident prediction of pharmaceutical drug behavior and delivery within the vitreous humor. (paper)

  6. Forensic Analysis of a Contact Lens in a Murder Case.

    Science.gov (United States)

    Zwerling, Charles S

    2016-03-01

    Contact lenses have had rare relevance in trials and/or investigations. After 5 years of burial, orbital remnants were retrieved from an exhumed body and subsequently identified as a key piece of material evidence in a murder trial. The exhumed case materials were evaluated under laboratory conditions and were determined to be contact lens remnants. Contact lens fracture and burial simulation studies were performed to provide additional corroboration of the physical findings of the exhumed contact lens remnants. This material evidence was instrumental in providing factual proof refuting the defendant's testimony in the murder trial. A brief history of contact lens composition and use is provided for understanding the methods and observational results. This forensic case study represents the first published documentation of a contact lens from an exhumed body being used in a murder investigation and establishes an operational procedure for future forensic contact lens examinations. © 2016 American Academy of Forensic Sciences.

  7. [Detection of leptospira by culture of vitreous humor and detection of antibodies against leptospira in vitreous humor and serum of 225 horses with equine recurrent uveitis].

    Science.gov (United States)

    Dorrego-Keiter, Elisa; Tóth, József; Dikker, Lieke; Sielhorst, Jutta; Schusser, Gerald Fritz

    2016-01-01

    In the ongoing discussion regarding the aetiopathogenesis of equine recurrent uveitis (ERU) it was the aim of the present study to elucidate the relationship of leptospira infection and ERU. In a population of 225 horses leptospira were examined in vitreous humor by culture and leptospira antibody were detected in vitreous humor and serum samples. Preoperative serum samples were collected from 221/225 ERU patients of different age, gender and breed. Undiluted vitreous humor was aseptically taken from 198/225 patients that underwent pars plana vitrectomy at the beginning of surgery and from 27/225 patients' eyeball after enucleation: Serum and vitreous humor were tested for specific leptospiral antibodies by microscopic agglutination test (MAT). Furthermore, vitreous humor was examined by culture. 20 patients which were euthanized due to a live-threatening disease other than ERU served as a control group. A total of 127/221 (57.5%) horses had serum antibodies (≥ 1:100). Most frequently antibodies against L. interrogans serovar Grippotyphosa were detected (79/127), followed by L. interrogans serovar lcterohaemorrhagiae (34/127) and L. interrogans serovar Bratislava (29/127). Only 79/225 horses (35.1%) had leptospiral antibodies in vitreous humor, in which L. interrogans serovar Grippotyphosa (67/79) was identified most frequently followed by L. interrogans serovar Pomona (18/79) and L. interrogans serovar lcterohaemorrhagiae (8/79) which was identified as single or multiple reaction. Isolation of leptospira from vitreous humor was positive in 34/212 horses (16%). 10/20 control horses had a positive antibody titer against leptospira in serum and 2/20 horses in vitreous humor, whereas there was no leptospira detected in culture. The result of 84% negative cultures from vitreous humor of 212 ERU patients is decisive for the diagnosis and therapy of ERU.

  8. Complex Study of the Physical Properties of Reticulated Vitreous Carbon

    Science.gov (United States)

    Alifanov, O. M.; Cherepanov, V. V.; Morzhukhina, A. V.

    2015-01-01

    We give an example of using a two-level identifi cation system incorporating an augmented mathematical model covering the structure, the thermal, electrophysical, and optical properties of nonmetallic ultraporous reticulated materials. The model, when combined with a nonstationary thermal experiment and methods of the theory of inverse heat transfer problems, permits determining the little studied characteristics of the above materials. We present some of the results of investigations of reticulated vitreous carbon confirming the possibility of using it in a number of engineering applications.

  9. REFRACTIVE NEUTRON LENS

    OpenAIRE

    Petrov, P. V.; Kolchevsky, N. N.

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  10. Contact lens in keratoconus

    OpenAIRE

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the En...

  11. Modern Phacoemulsification and Intraocular Lens Implantation (Refractive Lens Exchange) Is Safe and Effective in Treating High Myopia.

    Science.gov (United States)

    Srinivasan, Bhaskar; Leung, Hiu Ying; Cao, He; Liu, Shu; Chen, Lizhen; Fan, Alex Hoi

    Improved efficacy, predictability, and safety of modern phacoemulsification have resulted in cataract surgery being considered as a refractive procedure. Refractive lens exchange by definition is a surgery aimed at replacing the cataractous or clear crystalline lens with an intraocular lens (IOL) in cases of high ametropia. The excellent intraocular optics of this procedure provide a better visual outcome as compared with laser refractive surgery in high myopia. With advances in technology and IOL formulas, the predictability of refractive outcome after cataract surgery in high myopes has improved. The option of addressing presbyopia using multifocal/accommodating IOLs or monovision results in patients achieving reasonable spectacle independence. The most important concern with respect to phacoemulsification in high myopia is the risk of pseudophakic retinal detachment. High myopia is an independent risk factor for retinal detachment, and recent publications have reported a much lesser risk of retinal detachment specifically attributable to phacoemulsification in high myopes, especially if a thorough posterior segment evaluation is done and patients are followed up until development of complete posterior vitreous detachment. Refractive lens exchange is an effective and safe option to correct high myopia and can significantly improve quality of life in select patients.

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

    Science.gov (United States)

    Wilczyński, Michał; Wilczyńska, Olena; Omulecki, Wojciech

    2009-01-01

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

  13. Vitreous hemorrhage as a clue to late presenting Pulmonary Arterio Venous Malformation

    Directory of Open Access Journals (Sweden)

    Brijesh Takkar

    2017-10-01

    Full Text Available Retinal vasculature is frequently altered in systemic vascular disorders such as Diabetes and Hypertension. We present a rare case in which vitreous hemorrhage was the presenting sign of an underlying congenital cyanotic heart disease. Keywords: Vitreous hemorrhage, Cyanotic heart disease, Conjunctival telangiectasia

  14. Differential Vitreous Dye Diffusion Following Microplasmin or Plasmin Pre-Treatment

    NARCIS (Netherlands)

    Gad Elkareem, Ashraf M.; Willikens, Ben; Stassen, Jean Marie; de Smet, Marc D.

    2010-01-01

    Purpose: Plasmin and microplasmin are related enzymes that differ mainly in size. The differential effect of plasmin and microplasmin on vitreous structure, protein degradation, and dye diffusion through porcine vitreous was evaluated. Methods: The enzymatic effect was examined using a number of

  15. Electrochemical behaviour of uranium (IV) in DMF at vitreous carbon

    International Nuclear Information System (INIS)

    Afonso, M.L.; Gomes, A.; Carvalho, A.; Alves, L.C.; Wastin, F.; Goncalves, A.P.

    2009-01-01

    The electrochemical behaviour of UCl 4 (0.01 mol L -1 up to 0.05 mol L -1 ) in 0.1 mol L -1 TBAPF 6 /DMF solution at vitreous carbon was studied, at room temperature, by cyclic voltammetry and potentiostatic techniques. The electrolytic solutions were analyzed by UV spectroscopy (UV), and the electrodeposited films were characterized by Rutherford Backscattering Spectroscopy (RBS) and X-ray diffraction (XRD). The cyclic voltammetric results, at low UCl 4 concentrations (0.01 mol L -1 ), point that the reduction of U(IV) to U(0) occurs in two steps involving mainly U(IV) and U(III) species. The first electron transfer reaction is quasi-reversible and the second irreversible. The diffusion coefficient of U(IV) in DMF and the charge rate constant were determined to be 4.78 x 10 -7 cm 2 s -1 and 1.93 x 10 -3 cm s -1 (at 0.02 V s -1 ), respectively. RBS data obtained from samples prepared at constant potential (-3.10 V) during 3 h at room temperature, indicated the presence of uranium particles deposited all over the vitreous carbon surface with aggregates in some places, confirming that the second reduction step corresponds to uranium electrodeposition. No crystallographic ordering could be seen by XRD, pointing to an amorphous character of the uranium films.

  16. MR imaging of model drug distribution in simulated vitreous

    Directory of Open Access Journals (Sweden)

    Stein Sandra

    2015-09-01

    Full Text Available The in vitro and in vivo characterization of intravitreal injections plays an important role in developing innovative therapy approaches. Using the established vitreous model (VM and eye movement system (EyeMoS the distribution of contrast agents with different molecular weight was studied in vitro. The impact of the simulated age-related vitreal liquefaction (VL on drug distribution in VM was examined either with injection through the gel phase or through the liquid phase. For comparison the distribution was studied ex vivo in the porcine vitreous. The studies were performed in a magnetic resonance (MR scanner. As expected, with increasing molecular weight the diffusion velocity and the visual distribution of the injected substances decreased. Similar drug distribution was observed in VM and in porcine eye. VL causes enhanced convective flow and faster distribution in VM. Confirming the importance of the injection technique in progress of VL, injection through gelatinous phase caused faster distribution into peripheral regions of the VM than following injection through liquefied phase. VM and MR scanner in combination present a new approach for the in vitro characterization of drug release and distribution of intravitreal dosage forms.

  17. Enhanced vitreous imaging in healthy eyes using swept source optical coherence tomography.

    Science.gov (United States)

    Liu, Jonathan J; Witkin, Andre J; Adhi, Mehreen; Grulkowski, Ireneusz; Kraus, Martin F; Dhalla, Al-Hafeez; Lu, Chen D; Hornegger, Joachim; Duker, Jay S; Fujimoto, James G

    2014-01-01

    To describe enhanced vitreous imaging for visualization of anatomic features and microstructures within the posterior vitreous and vitreoretinal interface in healthy eyes using swept-source optical coherence tomography (SS-OCT). The study hypothesis was that long-wavelength, high-speed, volumetric SS-OCT with software registration motion correction and vitreous window display or high-dynamic-range (HDR) display improves detection sensitivity of posterior vitreous and vitreoretinal features compared to standard OCT logarithmic scale display. Observational prospective cross-sectional study. Multiple wide-field three-dimensional SS-OCT scans (500×500A-scans over 12×12 mm2) were obtained using a prototype instrument in 22 eyes of 22 healthy volunteers. A registration motion-correction algorithm was applied to compensate motion and generate a single volumetric dataset. Each volumetric dataset was displayed in three forms: (1) standard logarithmic scale display, enhanced vitreous imaging using (2) vitreous window display and (3) HDR display. Each dataset was reviewed independently by three readers to identify features of the posterior vitreous and vitreoretinal interface. Detection sensitivities for these features were measured for each display method. Features observed included the bursa premacularis (BPM), area of Martegiani, Cloquet's/BPM septum, Bergmeister papilla, posterior cortical vitreous (hyaloid) detachment, papillomacular hyaloid detachment, hyaloid attachment to retinal vessel(s), and granular opacities within vitreous cortex, Cloquet's canal, and BPM. The detection sensitivity for these features was 75.0% (95%CI: 67.8%-81.1%) using standard logarithmic scale display, 80.6% (95%CI: 73.8%-86.0%) using HDR display, and 91.9% (95%CI: 86.6%-95.2%) using vitreous window display. SS-OCT provides non-invasive, volumetric and measurable in vivo visualization of the anatomic microstructural features of the posterior vitreous and vitreoretinal interface. The

  18. Enhanced vitreous imaging in healthy eyes using swept source optical coherence tomography.

    Directory of Open Access Journals (Sweden)

    Jonathan J Liu

    Full Text Available To describe enhanced vitreous imaging for visualization of anatomic features and microstructures within the posterior vitreous and vitreoretinal interface in healthy eyes using swept-source optical coherence tomography (SS-OCT. The study hypothesis was that long-wavelength, high-speed, volumetric SS-OCT with software registration motion correction and vitreous window display or high-dynamic-range (HDR display improves detection sensitivity of posterior vitreous and vitreoretinal features compared to standard OCT logarithmic scale display.Observational prospective cross-sectional study.Multiple wide-field three-dimensional SS-OCT scans (500×500A-scans over 12×12 mm2 were obtained using a prototype instrument in 22 eyes of 22 healthy volunteers. A registration motion-correction algorithm was applied to compensate motion and generate a single volumetric dataset. Each volumetric dataset was displayed in three forms: (1 standard logarithmic scale display, enhanced vitreous imaging using (2 vitreous window display and (3 HDR display. Each dataset was reviewed independently by three readers to identify features of the posterior vitreous and vitreoretinal interface. Detection sensitivities for these features were measured for each display method.Features observed included the bursa premacularis (BPM, area of Martegiani, Cloquet's/BPM septum, Bergmeister papilla, posterior cortical vitreous (hyaloid detachment, papillomacular hyaloid detachment, hyaloid attachment to retinal vessel(s, and granular opacities within vitreous cortex, Cloquet's canal, and BPM. The detection sensitivity for these features was 75.0% (95%CI: 67.8%-81.1% using standard logarithmic scale display, 80.6% (95%CI: 73.8%-86.0% using HDR display, and 91.9% (95%CI: 86.6%-95.2% using vitreous window display.SS-OCT provides non-invasive, volumetric and measurable in vivo visualization of the anatomic microstructural features of the posterior vitreous and vitreoretinal interface. The

  19. Lipid partitioning in maize (Zea mays L.) endosperm highlights relationships among starch lipids, amylose, and vitreousness.

    Science.gov (United States)

    Gayral, Mathieu; Bakan, Bénédicte; Dalgalarrondo, Michele; Elmorjani, Khalil; Delluc, Caroline; Brunet, Sylvie; Linossier, Laurent; Morel, Marie-Hélène; Marion, Didier

    2015-04-08

    Content and composition of maize endosperm lipids and their partition in the floury and vitreous regions were determined for a set of inbred lines. Neutral lipids, i.e., triglycerides and free fatty acids, accounted for more than 80% of endosperm lipids and are almost 2 times higher in the floury than in the vitreous regions. The composition of endosperm lipids, including their fatty acid unsaturation levels, as well as their distribution may be related to metabolic specificities of the floury and vitreous regions in carbon and nitrogen storage and to the management of stress responses during endosperm cell development. Remarkably, the highest contents of starch lipids were observed systematically within the vitreous endosperm. These high amounts of starch lipids were mainly due to lysophosphatidylcholine and were tightly linked to the highest amylose content. Consequently, the formation of amylose-lysophosphatidylcholine complexes has to be considered as an outstanding mechanism affecting endosperm vitreousness.

  20. Vitreous humor and albumin augment the proliferation of cultured retinal precursor cells

    DEFF Research Database (Denmark)

    Yang, Jing; Klassen, Henry; Pries, Mette

    2008-01-01

    Intravitreal injection is an important delivery route for studies involving the transplantation of various types of precursor cells to the retina; however, the effect on these cells of exposure to the vitreous microenvironment has not been specifically investigated. Here vitreous humor was evalua......Intravitreal injection is an important delivery route for studies involving the transplantation of various types of precursor cells to the retina; however, the effect on these cells of exposure to the vitreous microenvironment has not been specifically investigated. Here vitreous humor...... was evaluated for the potential to influence the proliferation of rat retinal precursor cells in vitro. Cells were isolated at embryonic day 19 and plated in standard proliferation medium in the presence or absence of fluid expressed from porcine vitreous humor. Cellular proliferation at different...

  1. Late capsular bag contraction and intraocular lens subluxation in retinitis pigmentosa: a case report

    Directory of Open Access Journals (Sweden)

    Tsai Frank F

    2011-02-01

    Full Text Available Abstract Introduction Retinitis pigmentosa is clinically characterized by loss of predominantly rod photoreceptor function as well as loss of peripheral vision. The classic clinical triad is considered to be the presence of bone spicule pigmentation in the peripheral retina, arteriolar attenuation, and waxy disc pallor. Cataracts, most commonly of the posterior subcapsular type, are often found in all forms of retinitis pigmentosa. Ectopia lentis and lens dislocation are known risk factors for those with retinitis pigmentosa, presumably secondary to zonular fiber weakness and vitreous degeneration. The post-operative complication of lens dislocation following cataract extraction in patients with retinitis pigmentosa has also been documented. Case presentation We report a case of severe capsular bag contraction with intraocular lens subluxation following cataract extraction in a 58-year-old Hispanic woman with retinitis pigmentosa. Conclusion Patients with retinitis pigmentosa undergoing cataract surgery should be notified of this potentially late complication of surgery.

  2. CONTACT LENS RELATED CORNEAL ULCER

    Directory of Open Access Journals (Sweden)

    AGARWAL P

    2010-01-01

    Full Text Available A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are:overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. The presenting symptoms of contact lens related corneal ulcers include eye discomfort, foreign body sensation and lacrimation. More serious symptoms are redness (especially circum-corneal injection, severe pain, photophobia, eye discharge and blurring of vision. The diagnosis is established by a thorough slit lamp microscopic examination with fluorescein staining and corneal scraping for Gram stain and culture of the infective organism. Delay in diagnosing and treatment can cause permanent blindness, therefore an early referral to ophthalmologist and commencing of antimicrobial therapy can prevent visual loss.

  3. Extent of Detached Retina and Lens Status Influence Intravitreal Protein Expression in Rhegmatogenous Retinal Detachment.

    Science.gov (United States)

    Pollreisz, Andreas; Sacu, Stefan; Eibenberger, Katharina; Funk, Marion; Kivaranovic, Danijel; Zlabinger, Gerhard J; Georgopoulos, Michael; Schmidt-Erfurth, Ursula

    2015-08-01

    The aim of the study was to compare intravitreal cytokines and chemokines to clinical parameters in patients with rhegmatogenous retinal detachment (RRD). In this prospective study vitreous samples were taken undiluted from 60 patients with RRD and 20 age-matched controls with idiopathic epiretinal membranes at the beginning of primary vitrectomy. The following clinical parameters were assessed from RRD patients prior to surgery: number of quadrants detached, RD height, lens status, symptom duration, and refractive power. Concentrations of 40 different proteins in the vitreous of RRD eyes were measured by multiplex protein array, compared with controls and correlated to clinical parameters. Ten cytokines and chemokines were significantly upregulated in the vitreous of RRD eyes compared with controls (tissue inhibitors of metalloproteinases [TIMP]-1 and -2, macrophage inflammatory protein [MIP]-1α, monocyte chemoattractant protein [MCP]-1, IL-6, and -8, inducible protein (IP)-10, brain-derived neurotrophic factor [BDNF], TGFβ-3, and platelet-derived growth factor [PDGF]-AB/BB). Linear regression analysis revealed that IL-8 and TGFβ-3 increased with the number of retinal quadrants detached, while TIMP-1 rose in eyes with greater RD heights. Concentrations of IP-10 and myeloperoxidase (MPO) peaked in eyes with two or more quadrants detached, while TIMP-2 was highest expressed in the vitreous of eyes with great RD height. In pseudophakic eyes with higher detachment height levels of vascular cell adhesion molecule (VCAM)-1 were significantly increased, while neural cell adhesion molecule (NCAM) was decreased in pseudophakic patients with shallow RD height. Extent of RRD and lens status significantly influence intravitreal proinflammatory, profibrotic, and proapoptotic protein expression. These data contribute to the fundamental understanding of pathophysiological mechanisms in RRD and may serve as a basis for development of adjunct therapeutics to facilitate

  4. Synchrotron radiation analysis on ancient Egyptian vitreous materials

    Energy Technology Data Exchange (ETDEWEB)

    Yamahana, Kyoko [Tokai Univ., Hiratsuka, Kanagawa (Japan). Lecture of Egyptian Archaeology

    2000-07-01

    Ancient Egyptian vitreous materials, namely faience and glass, share the same elemental composition. But they appear to have originated separately. Faience objects appear as early as the Predynastic period, and glass was introduced from Mesopotamia during the New Kingdom. These faience and glass objects were not of daily use, rather they were regarded as religious symbols or luxury status goods. Most of the products were coloured blue, but we see an increased use of other colours during the New Kingdom (c.1550-1069BC). This tendency corresponds to the period of both territorial and political expansion of Egypt. A non-destructive SR-XRF experiment at SPring-8 was conducted last winter, aiming to determine the regional trait of elemental composition by examining the pattern and ratio of rare earth elements. As a result, we could observe some distinctive rare earth elements that may indicate regional variation. (author)

  5. An injectable oxidated hyaluronic acid/adipic acid dihydrazide hydrogel as a vitreous substitute.

    Science.gov (United States)

    Su, Wen-Yu; Chen, Ko-Hua; Chen, Yu-Chun; Lee, Yen-Hsien; Tseng, Ching-Li; Lin, Feng-Huei

    2011-01-01

    Vitrectomy is a common procedure for treating ocular-related diseases. The surgery involves removing the vitreous humor from the center of the eye, and vitreous substitutes are needed to replace the vitreous humor after vitrectomy. In the present study, we developed a colorless, transparent and injectable hydrogel with appropriate refractive index as a vitreous substitute. The hydrogel is formed by oxidated hyaluronic acid (oxi-HA) cross-linked with adipic acid dihydrazide (ADH). Hyaluronic acid (HA) was oxidized by sodium periodate to create aldehyde functional groups, which could be cross-linked by ADH. The refractive index of this hydrogel ranged between 1.3420 and 1.3442, which is quite similar to human vitreous humor (1.3345). The degradation tests demonstrated that the hydrogel could maintain the gel matrix over 35 days, depending on the ADH concentration. In addition, the cytotoxicity was evaluated on retina pigmented epithelium (RPE) cells cultivated following the ISO standard (tests for in vitro cytotoxicity), and the hydrogel was found to be non-toxic. In a preliminary animal study, the oxi-HA/ADH hydrogel was injected into the vitreous cavity of rabbit eyes. The evaluations of slit-lamp observation, intraocular pressure, cornea thickness and histological examination showed no significant abnormal biological reactions for 3 weeks. This study suggests that the injectable oxi-HA/ADH hydrogel should be a potential vitreous substitute. Koninklijke Brill NV, Leiden, 2011

  6. Negative effects of transthyretin in high myopic vitreous on diabetic retinopathy

    Directory of Open Access Journals (Sweden)

    Jun Shao

    2017-12-01

    Full Text Available AIM: To analyze the relationship between vitreous transthyretin (TTR levels, high myopia and diabetic retinopathy (DR. METHODS: We selected 6722 individuals from the southern Jiangsu Province for diabetes and ophthalmic examinations. The TTR concentration in the vitreous of 50 patients with high myopia and diabetes, 50 patients with only DR, and 20 healthy controls were determined by ELISA. Key factors in Tie2 pathway in DR development including vascular endothecial growth factor (VEGF, Tie2, Angpt1, Angpt2, vascular endothelial growth factor receptor (VEGFR 1 and VEGFR2 were also detected by ELISA. RESULTS: The prevalence of DR in patients with diabetes and myopia [6.00 D, and diabetes without myopia were 11.1%, 2.5%, and 60.0%, respectively. The vitreous TTR concentration of patients with diabetes and high myopia was approximately 6.5- and 4.2-times higher than those of patients with DR and healthy controls, respectively (P<0.05. Following the vitreous TTR concentration, the levels of VEGF, Tie2, Angpt1, Angpt2, VEGFR1 and VEGFR2 in vitreous of diabetes and high myopia patients, DR patients and healthy controls were detected as dramatically fluctuated. CONCLUSION: The results suggest that TTR can affect the vitreous contents of key factors in Tie2 pathway for neovascularization, and there should be a protective association between abundant TTR levels in the vitreous of highly myopic patients and a decreased risk of DR.

  7. Reticulated vitreous carbon: a useful material for cell adhesion and tissue invasion

    Directory of Open Access Journals (Sweden)

    MK Pec

    2010-10-01

    Full Text Available Diverse carbon materials have been used for tissue engineering and clinical implant applications with varying success. In this study, commercially available reticulated vitreous carbon (RVC foams were tested in vitro and in vivo for compatibility with primary cell adhesion and tissue repair. Pores sizes were determined as 279 ± 98 µm. No hydroxyapatite deposition was detected after immersion of the foams in simulated body fluid. Nonetheless, RVC provided an excellent support for adhesion of mesenchymal stem cells (MSCs as well as primary chondrocytes without any surface pre-treatment. Live cell quantification revealed neutral behaviour of the material with plastic adhered chondrocytes but moderate cytotoxicity with MSCs. Yet, rabbit implanted foams exhibited good integration in subcutaneous pockets and most importantly, total defect repair in bone. Probably due to the stiffness of the material, incompatibility with cartilage regeneration was found. Interestingly and in contrast to several other carbon materials, we observed a total lack of foreign body reactions. Our results and its outstanding porous interconnectivity and availability within a wide range of pore sizes convert RVC into an attractive candidate for tissue engineering applications in a variety of bone models and for ex vivo cell expansion for regenerative medical applications.

  8. Body

    OpenAIRE

    Riggs, Christina

    2010-01-01

    The human body is both the physical form inhabited by an individual “self” and the medium through which an individual engages with society. Hence the body both shapes and is shaped by an individual’s social roles. In contrast to the cognate fields of archaeology, anthropology, and classics, there has been little explicit discussion or theorization of the body in Egyptology. Some recent works, discussed here, constitute an exception to this trend, but there is much more scope for exploring anc...

  9. Traction on the retina induced by saccadic eye movements in the presence of posterior vitreous detachment.

    Science.gov (United States)

    Repetto, R; Tatone, A; Testa, A; Colangeli, E

    2011-04-01

    Posterior vitreous detachment is a fairly common condition in elderly people. Tractions exerted by the detached vitreous on the retina may result in retinal tears and detachments. We studied how these tractions can arise from saccadic eye movements. Numerical simulations have been performed on a two-dimensional model of the vitreous chamber within a rigid spherical sclera, subjected to prescribed finite-amplitude rotations about a vertical axis. The vitreous chamber was assumed to be split into two regions: one occupied by the detached vitreous, modeled as an elastic viscous solid, and the other occupied by the separated liquefied vitreous, modeled as a Newtonian fluid. At the interface between the two phases, we also considered the presence of the vitreous cortex, modeled as an elastic membrane. We tested several different configurations of the interface. In all cases, we found that eye rotations generate large tractions on the retina close to the attachment points of the membrane. Comparing them, we identified configurations of the vitreous detachment that exhibit higher tractions. We also investigated how the response to saccadic movements depends on some physical parameters, in particular on the rheological properties of the solid phase and the membrane. The numerical simulations show that the generated tractions may be of the same order of magnitude as the adhesive force between the retina and the pigment epithelium. Therefore, the model provides a sound physical justification for the hypothesis that saccadic movements, in the presence of posterior vitreous detachment, could be responsible for high tractions on the retina, which may trigger retinal tear formation.

  10. Results and complications of scleral fixated (Sutured posterior chamber intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Amoozadeh J

    2001-08-01

    Full Text Available Optical rehabilitation of the patient with aphakia who cannot tolerate contact lenses present a therapeutic challenge. In the absence of capsular support, anterior chamber lenses have been widely used. On the other hand intraocular lens implantation of scleral sutured posterior chamber intraocular lens during penterating keratoplasty or insufficient iris support is recommended. The purpose of this study is to evaluate the clinical outcome and complication in 17 patients who underwent scleral-fixation of an intraocular lens.We studied prospectively the results of posterior chamber intraocular lens implantation by scleral fixation in 17 eyes of 17 patients without a complete posterior lens capsule support at farabi Eye Hospital. Uncorrected visual acuity improved from counting finger to 20/40 or better in 9 eyes (53 percent. The following complications were observed during the mean postoperative follow-up of 7.2 (range 3-12 months; increased intraocular pressure in 5 eyes, vitreous hemorrhage and icr hyphema in 2 eyes, cystoid macular edema (CME and vitritis in one eye, and endophthalmitis and retinal detachment in one eye. Posterior chamber intraocular lens implantation by scleral fixation is a relatively safe procedure and can be recommended for many patients

  11. Ligands and modifiers in vitreous materials the spectroscopy of condensed systems

    CERN Document Server

    Margaryan, Alfred

    1999-01-01

    The study of the effect of ligand and modifier ions on the spectroscopic properties of dn or fn elements in vitreous materials is important for the development of controllable lasers and amplifiers. The spectroscopic characteristics of inorganic compounds of transition elements and their solutions are well understood theoretically in the spectrochemistry of complexes, but developments for vitreous materials in these conditions have not been well documented. This book fills the gap by applying the ligand field theory of solid materials to the vitreous state, and presenting the data obtained fro

  12. Vitreous haemorrhage in massive hemorrhagic polypoidal choroidal vasculopathy: clinical characteristics and surgical outcomes: Vitreous hemorrhage in PCV.

    Science.gov (United States)

    Narayanan, Raja; Mithal, Kopal; Jalali, Subhadra; Chhablani, Jay Kumar; Mathai, Annie; Ali, Md Hasnat

    2015-01-01

    To report the outcomes of vitreous hemorrhage (VH) associated with hemorrhagic polypoidal choroidal vasculopathy (PCV). A retrospective study of 28 eyes of 27 consecutive patients of hemorrhagic PCV with VH, which were managed surgically between January 2003 and December 2011, was performed. All patients underwent pars plana vitrectomy for VH associated with PCV. The main outcome measure was best-corrected visual acuity (BCVA) at baseline, at 1, 3 and 6 months post operatively and at last follow up. The visual acuity measured on early treatment diabetic retinopathy study (ETDRS) chart improved in 16 eyes (57.1 %) by two or more lines, remained unchanged in nine eyes (32.1 %) and decreased in three (10.7 %) after surgery when compared to baseline VA. The mean baseline VA was 2.69 ± 0.57 logMAR units (hemorrhagic PCV have sustained improvement in visual acuity following surgery.

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... new application of artificial intelligence shows whether a patient’s eyes point to high blood pressure or risk ...

  14. Colored Contact Lens Dangers

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    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  15. Colored Contact Lens Dangers

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    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  16. Colored Contact Lens Dangers

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    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her ...

  17. Colored Contact Lens Dangers

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    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...

  18. Colored Contact Lens Dangers

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    Full Text Available ... with Colored Contact Lenses Julian: Teenager Blinded In One Eye By Non-Prescription Contact Lens Laura: Vision ... Robyn: Blurry Vision and Daily Eye Drops After One Use Facts About Colored Contacts and Halloween Safety ...

  19. Colored Contact Lens Dangers

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    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For ...

  20. Colored Contact Lens Dangers

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    Full Text Available ... in a pair of colored contact lenses, Laura Butler of Parkersburg, W.Va., had "extreme pain in ... to wear any kind of contact lens. In Butler's case, the lenses caused an infection and left ...

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  2. Colored Contact Lens Dangers

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    Full Text Available ... an impulsive buy from a souvenir shop, but 10 hours after she first put in a pair ... Prescription Contact Lens Laura: Vision Loss After Just 10 Hours Robyn: Blurry Vision and Daily Eye Drops ...

  3. bubble chamber lens

    CERN Multimedia

    Before the days of electronic detectors, visual techniques were used to detect particles, using detectors such as spark chambers and bubble chambers. This plexiglass lens was used to focus the image of tracks so they could be photographed.

  4. Colored Contact Lens Dangers

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    Full Text Available ... Contact Lens Facts Over-the-Counter Costume Contacts May Contain Chemicals Harmful to Eyes Four Ways Over- ... without a prescription are breaking the law, and may be fined $11,000 per violation. "Many of ...

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ...

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... an ophthalmologist — an eye medical doctor — who will measure each eye and talk to you about proper ...

  7. Colored Contact Lens Dangers

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    Full Text Available ... prescription. Follow the contact lens care directions for cleaning, disinfecting, and wearing the lenses. Never share contact ... with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American ...

  8. Viscous froth lens

    Science.gov (United States)

    Green, T. E.; Bramley, A.; Lue, L.; Grassia, P.

    2006-11-01

    Microscale models of foam structure traditionally incorporate a balance between bubble pressures and surface tension forces associated with curvature of bubble films. In particular, models for flowing foam microrheology have assumed this balance is maintained under the action of some externally imposed motion. Recently, however, a dynamic model for foam structure has been proposed, the viscous froth model, which balances the net effect of bubble pressures and surface tension to viscous dissipation forces: this permits the description of fast-flowing foam. This contribution examines the behavior of the viscous froth model when applied to a paradigm problem with a particularly simple geometry: namely, a two-dimensional bubble “lens.” The lens consists of a channel partly filled by a bubble (known as the “lens bubble”) which contacts one channel wall. An additional film (known as the “spanning film”) connects to this bubble spanning the distance from the opposite channel wall. This simple structure can be set in motion and deformed out of equilibrium by applying a pressure across the spanning film: a rich dynamical behavior results. Solutions for the lens structure steadily propagating along the channel can be computed by the viscous froth model. Perturbation solutions are obtained in the limit of a lens structure with weak applied pressures, while numerical solutions are available for higher pressures. These steadily propagating solutions suggest that small lenses move faster than large ones, while both small and large lens bubbles are quite resistant to deformation, at least for weak applied back pressures. As the applied back pressure grows, the structure with the small lens bubble remains relatively stiff, while that with the large lens bubble becomes much more compliant. However, with even further increases in the applied back pressure, a critical pressure appears to exist for which the steady-state structure loses stability and unsteady

  9. Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears

    Science.gov (United States)

    Townsend, Dennis P.; Patel, P. R.

    1988-01-01

    Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

  10. Uveitis, vitreous humour, and Klebsiella. II. Cross-reactivity studies with radioimmunoassay

    International Nuclear Information System (INIS)

    Welsh, J.; Avakian, H.; Ebringer, A.

    1981-01-01

    Radioimmunoassay with calf and cow vitreous humour -125 I and rabbit antivitreous humour serum was employed to investigate the immunological cross-reactivity of vitreous humour with bacterial and mammalian tissue antigens. Klebsiella ultrasonicate preparation at a dose of 10 000 μg/ml was found to inhibit the binding of vitreous humour by 25-100% (p < 0.001), compared with an inhibition of 5-30% by a similar quantity of E. coli ultrasonicate preparation. Equivalent amounts of Streptococcus pyogenes antigen, bovine haemoglobin, and hyaluronic acid had no inhibitory effect, while horse spleen ferritin was found to inhibit vitreous humour binding between 0 and 10%. These results indicate that klebsiella micro-organisms have antigens which partially resemble some eyeball components. It is suggested that acute anterior uveitis of ankylosing spondylitis may be produced by anti-Gram-negative bacterial antibodies binding to cross-reacting eye antigens. (author)

  11. Hydraulic Resistance of Vitreous Cutters: The Impact of Blade Design and Cut Rate.

    Science.gov (United States)

    Rossi, Tommaso; Querzoli, Giorgio; Angelini, Giampiero; Malvasi, Carlo; Rossi, Alessandro; Morini, Mario; Esposito, Graziana; Micera, Alessandra; di Luca, Natale Mario; Ripandelli, Guido

    2016-07-01

    To measure the hydraulic resistance (HR) of vitreous cutters equipped with a Regular guillotine Blade (RB) or double edge blade (DEB) at cut rates comprised between 0 and 12,000 cuts per minute (CPM) and compare it with vitreous fragment size. This was an in vitro experimental study; in vivo HR measure and vitreous sampling. HR, defined as aspiration pressure/flow rate, was measured in balanced salt solution (BSS; Alcon, Fort Worth, TX) (in vitro) and during pars plana vitrectomy of 20 consecutive patients aged 18 to 65, undergoing macular surgery. HR was recorded at increasing cut rates (500-6000 CPM for the RB and 500-12,000 CPM for the DEB; 5 mL/min flow). Vitreous samples were withdrawn and analyzed with Western and collagen type II and IX immunostaining to evaluate protein size. The main outcome measures were hydraulic resistance (mm Hg/ml/min [±SD]) and optic density for Western blot and immunostaining. RB and DEB showed identical HR in BSS between 0 and 3000 CPM. Above 3000 CPM, RB HR steadily increased, and was significantly higher than DEB HR. Vitreous HR was also similar for the two blades between 0 and 1500 CPM. Above 1500 CPM, RB offered a significantly higher resistance. Western blot and immunostaining of vitreous samples did not yield a significant difference in size, regardless of blade type and cut rate. DEB is more efficient, offering a lower HR than RB over 1500 CPM in human vitreous. There is no viscosity reduction as a function of cut-rate between 1500 and 12,000 CPM, as HR does not vary. Future vitreous cutters will benefit of a DEB; optimal cut rate needs to be defined, and the simple increase of cut rate does not provide benefits after a certain limit to be assessed.

  12. Proteomic Analysis of the Vitreous following Experimental Retinal Detachment in Rabbits

    DEFF Research Database (Denmark)

    Mandal, Nakul; Lewis, Geoffrey P.; Fisher, Steven K.

    2015-01-01

    of the vitreous following experimental retinal detachment using a comparative proteomic based approach. Materials and Methods. Retinal detachment was created in the right eyes of six New Zealand red pigmented rabbits. Sham surgery was undertaken in five other rabbits that were used as controls. After seven days......, and α-1-antiproteinase F. Conclusions. Proteomic investigation of the rabbit vitreous has identified a set of proteins that help further our understanding of the pathogenesis of rhegmatogenous retinal detachment and its complications....

  13. Evidence for vitreous type orientational ordering in solid hydrogen and deuterium

    International Nuclear Information System (INIS)

    Devoret, M.

    1982-09-01

    This shown a new region in the concentration-temperature phase diagram for solid mixtures of ortho and para-hydrogen. This region is characterized by a vitreous type orientational, ordering, with the quadrupoles of the ortho molecules frozen in a random fashion. This new vitreous state is called a quadrupolar glass, with the degrees of freedom of quadrupolar moments frozen in solid hydrogen [fr

  14. [Surgery in posterior luxated lens fragments through intravitreal phacofragmentation].

    Science.gov (United States)

    Branisteanu, D; Moraru, Andreea

    2013-01-01

    To assess the intra and postoperative difficulties, the anatomical and functional results after intravitreal phacoemulsification during pars plana vitrectomy for retained intraocular lens fragments. Retrospective, non-comparative case series of 48 eyes who underwent vitrectomy for posterior dislocated lens fragments during phacoemulsification between January 2000 and January 2010. In 11 cases the vitrectomy was performed immediately, within 24 hours, and in 37 cases it was delayed 2 to 10 days after cataract surgery. During pars plana vitrectomy the lens fragments were separated of vitreous strings and then phacoemulsification was performed into the center of vitreous cavity. All cases were performed under local anesthesia by the same surgeon. During vitrectomy PFCL was used in 5 cases to protect central retina. Cases were followed-up at least 6 months. Statistical analysis was performed using Wilcoxon and chi square tests. Mean age in the study group was 65.38% 9.49 years (ranging 52-82 years). The mean visual acuity improved from 0.12% 0.07 (0.04-0.3) preoperatively to 0.3% 0.2 (0.05-0.6) postoperatively (p < 0.01). Mean intraocular pressure decreased postoperatively from 26.24% 9.3 mmHg (16-48 mmHg) to 15.95% 3.69 mmHg(12-24 mmHg) (p < 0.01). In all cases corneal edema and intraocular inflammation ceased after vitrectomy. In those 11 cases operated immediately the intravitreal phacoemulsification time was longer, as well as greater number of intraoperative complication (corneal edema, corneal leakage). In 4 out of these 11 cases (36.36%) severe postoperative retinal complications were noticed (2 cases of retinal detachment, 1 case of choroidal detachment and 1 case of choroidal hematoma). In the delayed group the only postoperative complication was cystoid macular edema in 9 out of 37 cases (24.32%). Removal of retained intraocular lens fragments suspended the intraocular inflammation and normalized intraocular pressure in all cases. Our results are in favor of

  15. Vitreous and plasma VEGF levels as predictive factors in the progression of proliferative diabetic retinopathy after vitrectomy.

    Directory of Open Access Journals (Sweden)

    Jiaxing Wang

    Full Text Available To investigate the vitreous and plasma levels of vascular endothelial growth factor (VEGF in patients with proliferative diabetic retinopathy (PDR and to determine whether they predict a disease prognosis after primary vitrectomy.Fifty patients (50 eyes with PDR who underwent pars plana vitrectomy (PPV and 56 healthy controls (56 eyes were enrolled in this retrospective study. Clinical data were collected and analyzed. Vitreous and plasma VEGF concentrations were measured using enzyme-linked immunosorbent assays. VEGF levels and clinical data were compared and analyzed to see if they provide a prognosis of PDR progression after primary vitrectomy at more than 6 months follow-up. Correlation of VEGF concentrations between vitreous fluid and plasma was analyzed.The average BCVA was significantly improved after surgery (P<0.001. Vitreous and plasma VEGF levels were significantly elevated in PDR patients than those in healthy controls (P vitreous<0.001; P plasma<0.001. Both vitreous and plasma VEGF levels were significantly higher in PDR progression group than in stable group (P vitreous < 0.001; P plasma = 0.004. Multivariate logistic regression analyses showed that the increased vitreous VEGF level was associated with the progression of PDR after primary PPV (OR = 1.539; P = 0.036. Vitreous VEGF level was positively associated with plasma VEGF level in PDR patients (P<0.001.The increased VEGF level in vitreous fluid may be identified as a significant predictive factor for the outcome of vitrectomy in patients with PDR.

  16. Association of serum and vitreous concentrations of osteoprotegerin with diabetic retinopathy.

    Science.gov (United States)

    Yu, Gehua; Ji, Xiaoyan; Jin, Ji; Bu, Shuyang

    2015-03-01

    Angiogenesis is involved in the pathogenesis of diabetic retinopathy. Osteoprotegerin, a recently identified glycoprotein belonging to the tumour necrosis factor receptor superfamily, has been implicated to be correlated with angiogenesis. This study aims to determine whether serum and vitreous concentrations of osteoprotegerin are associated with diabetic retinopathy. This study consisted of 254 diabetic patients (100 without diabetic retinopathy, 64 with non-proliferative diabetic retinopathy and 90 with proliferative diabetic retinopathy) and 62 control subjects. Serum and vitreous concentrations of osteoprotegerin were evaluated using enzyme-linked immunosorbent assay method. Serum and vitreous osteoprotegerin concentrations in proliferative diabetic retinopathy patients were significantly elevated compared with those of the other three groups. Non-proliferative diabetic retinopathy patients showed elevated concentrations of serum and vitreous osteoprotegerin compared with patients without diabetic retinopathy. In addition, control subjects had significantly lower serum and vitreous osteoprotegerin concentrations compared with diabetic patients without retinopathy, non-proliferative diabetic retinopathy patients and proliferative diabetic retinopathy patients. Serum and vitreous osteoprotegerin concentrations are associated with the presence and severity of diabetic retinopathy. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  17. Bromatological characteristics and ruminal digestibility of grain corn hybrids with different vitreousness in silage maturity

    Directory of Open Access Journals (Sweden)

    Evandrei Santos Rossi

    2016-06-01

    Full Text Available The aim of this research was to evaluate vitreousness in commercial corn hybrids with flint and dent grains and to study the effect of this characteristic on agronomic behavior, nutritional value, and ruminal degradability of grains harvested in silage maturity. Twelve commercial corn hybrids were evaluated. They were divided in two groups (six with flint grains and six with dent grains. The experiments were conducted in two municipalities represented by Guarapuava and Laranjeiras do Sul, both in Paraná State. The harvest for the grain quality analysis was performed at ¾ of the milk line stage in the grain. The following characteristics were evaluated: grain yield, grain yield in silage maturity, vitreousness, ruminal digestibility of grain, neutral detergent fiber, acid detergent fiber and crude protein. The grains in the group of dent hybrids exhibited better degradability associated with lower vitreousness than the group of flint hybrids. The group of dent hybrids exhibited better ruminal digestibility of the grains associated with lower vitreousness versus the group of flint hybrids. There is a negative correlation between vitreousness and the digestibility of the grain; thus, vitreousness can be a criterion for selecting genotypes for forage production.

  18. Vitreous occlusion of tube implant in a phakic patient with traumatic glaucoma

    Directory of Open Access Journals (Sweden)

    Suneeta Dubey

    2014-01-01

    Full Text Available Tube implants or glaucoma drainage devices have become an important method of intraocular pressure reduction when treating complex cases of traumatic glaucoma. However, it is not uncommon to have complications associated with tube implants. The optimal treatment of patients who have undergone glaucoma implant surgery complicated by vitreous incarceration is uncertain. If vitreous is present or is able to prolapse into anterior chamber, as in aphakic or pseudophakic patient without an intact posterior capsule, a concurrent anterior vitrectomy is usually performed. In such cases, pars plana vitrectomy has been found to be more effective in several studies. However, there are no set guidelines for management of such a case in a phakic eye and the management can be more challenging especially when there is no obvious deficiency in posterior capsule, zonular dialysis, or loose vitreous gel in the anterior chamber prior to or during tube implantation. We describe a case of 14-year-old phakic patient with traumatic glaucoma without vitreous gel in anterior chamber whose tube implant became occluded by vitreous resulting in increased intra ocular pressure. This is the first documented report of vitreous incarceration in a phakic patient and its successful management.

  19. Optic Nerve Head Hemorrhages Associated With Posterior Vitreous Detachment.

    Science.gov (United States)

    Polkinghorne, Philip J

    2018-01-01

    To report and evaluate the clinical and optical coherence tomography (OCT) features of optic nerve hemorrhages (ONH) associated with spontaneous posterior vitreous detachment (PVD). A prospective case series conducted at a private ophthalmic practice in Auckland, New Zealand. A consecutive series of patients presenting at a private multispecialty practice in Auckland, New Zealand, with symptoms of PVD with ONH underwent imaging of the optic nerve with digital retinal photography and OCT. The number and location of each hemorrhage were recorded, together with relevant ophthalmic and demographic data. Twenty of 30 eyes with ONH had evidence of persistent vitreopapillary adhesion. Three patterns of adhesion were identified: central, peripheral, and combined. In all, 52 hemorrhages were identified, of which the majority were flame-shaped, although other types were seen including dot and blot hemorrhages. One subretinal hemorrhage occurred in a patient with a central vitreopapillary adhesion. ONH hemorrhages associated with PVD are commonly found with persistent vitreopapillary adhesions as evidenced on OCT. The clinical features of ONH together with OCT imaging may help to distinguish ONH associated with PVD from other hemorrhages found on or adjacent to the optic nerve. Copyright 2017 Asia-Pacific Academy of Ophthalmology.

  20. A catoptric lens

    International Nuclear Information System (INIS)

    Rambauske, W.R.

    1973-01-01

    The invention relates to a catoptric lens for combining energies transmitted by several sources such as lasers; said lens comprising mirrors, the reflective surfaces of which have their focuses spaced from a common axis of symmetry. By means of these reflecting surfaces, which are generated by the nutation of portions of quadratic conics about the axis of symmetry, it is possible to focus the energy emmited by several lasers at the focus of the exit-mirror reflecting surface. This can be applied to thermonuclear fusion [fr

  1. Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye

    Science.gov (United States)

    Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Iturbide-Jiménez, F.; Martínez-López, M.; Ramírez-Como, M.; Armengol-Cruz, V.; Vásquez-Báez, I.

    2014-09-01

    Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.

  2. Quadrupole magnetic lens

    International Nuclear Information System (INIS)

    Piskunov, V.A.

    1981-01-01

    The following connection of windings of electromagnet is suggested for simplification of the design of qUadrupole magnetic lens intended for use in radiotechnical and electron-optical devices. The mentioned windings are connected with each other by a bridge scheme and the variable resistors are switched in its diagonals in the lens containing four electromagnet with windings connected with two variable resistors the mobile contacts of which are connected with a direct current source. Current redistribution between left windings and right windings takes place at shift of mobile contact of variable resistor, and current redistribution between upper and low coils of electromagnets takes place at shifting mobile contact of the other variable resistor. In this case smooth and independent electron-optical misalignment of lens by two mutually perpendicular directions proceeds. Use of the given design of the lens in the oscillograph permits to use printing assembly for alignment plate and to reduce the number of connections at the expense of decreasing the number of resistors

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into the cornea. Even if you have perfect vision, you need to get an eye exam and a prescription ...

  4. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ...

  5. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  6. The Lens of Chemistry

    Science.gov (United States)

    Thalos, Mariam

    2013-01-01

    Chemistry possesses a distinctive theoretical lens--a distinctive set of theoretical concerns regarding the dynamics and transformations of a perplexing variety of organic and nonorganic substances--to which it must be faithful. Even if it is true that chemical facts bear a special (reductive) relationship to physical facts, nonetheless it will…

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her with a corneal ... A recent article from U.S. News and World Report explains what ophthalmologists are and how they can ...

  8. bubble chamber lens

    CERN Multimedia

    Was used in a PS experiment. Before the days of electronic detectors, visual techniques were used to detect particles, using detectors such as spark chambers and bubble chambers. This plexiglass lens was used to focus the image of tracks so they could be photographed.

  9. Thermal Lens Microscope

    Science.gov (United States)

    Uchiyama, Kenji; Hibara, Akihide; Kimura, Hiroko; Sawada, Tsuguo; Kitamori, Takehiko

    2000-09-01

    We developed a novel laser microscope based on the thermal lens effect induced by a coaxial beam comprised of excitation and probe beams. The signal generation mechanism was confirmed to be an authentic thermal lens effect from the measurement of signal and phase dependences on optical configurations between the sample and the probe beam focus, and therefore, the thermal lens effect theory could be applied. Two-point spatial resolution was determined by the spot size of the excitation beam, not by the thermal diffusion length. Sensitivity was quite high, and the detection ability, evaluated using a submicron microparticle containing dye molecules, was 0.8 zmol/μm2, hence a distribution image of trace chemical species could be obtained quantitatively. In addition, analytes are not restricted to fluorescent species, therefore, the thermal lens microscope is a promising analytical microscope. A two-dimensional image of a histamine molecule distribution, which was produced in mast cells at the femtomole level in a human nasal mucous polyp, was obtained.

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... an Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact ... After One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter ...

  11. Clinical survey of lens care in contact lens patients.

    Science.gov (United States)

    Ky, W; Scherick, K; Stenson, S

    1998-10-01

    Overall, contact lenses provide a safe and effective modality for vision correction. However, problems do occasionally arise. Up to 80% of contact lens complications can be traced to poor patient compliance with recommended lens care guidelines. We conducted a survey to evaluate the level of patient compliance in specific areas of lens care and maintenance and to assess patient knowledge of basic contact lens information. Patients were asked to complete an anonymous 15 question survey that focused on lens care--specifically the use of contact lens cleaners, methods of disinfection, enzyme treatments, use of rewetting drops, and the frequency of follow-up exams. In addition, the survey included six true/false questions relating to contact lens care and safety. There were a total of 103 participants in the study. Approximately 24% of patients stated they never cleaned their lenses prior to disinfection, and 5% used saline solutions as their primary mode of disinfection. A sizable portion of those surveyed (43% of soft lens wearers and 71% of rigid gas permeable lens wearers) either never used enzyme cleaners or used them less than once a month. Seventy percent of patients either never used rewetting drops or used them less than once a day. Twenty-nine percent of patients consulted their eye care professionals every 2 years and 6% less often than every two years. Six questions assessed patient knowledge of contact lens care safety. Of a possible six out of six correct answers, the mean number of correct responses was 3.74. A sizable proportion of contact lens wearers do not adequately adhere to recommended contact lens care, and many have an inadequate understanding of contact lens care guidelines. Therefore, it is important that practitioners place more emphasis on patient education at the time of initial contact lens fitting and reinforce such instruction during follow-up visits.

  12. Noncontact optical measurement of lens capsule thickness ex vivo

    Science.gov (United States)

    Ziebarth, Noel M.; Manns, Fabrice; Uhlhorn, Stephen; Parel, Jean-Marie

    2004-07-01

    Purpose: To design a non-contact optical system to measure lens capsule thickness in cadaver eyes. Methods: The optical system uses a 670nm laser beam delivered to a single-mode fiber coupler. The output of the fiber coupler is focused onto the tissue using an aspheric lens (NA=0.68) mounted on a motorized translation stage. Light reflected from the sample is collected by the fiber coupler and sent to a silicon photodiode connected to a power meter. Peaks in the power signal are detected when the focal point of the aspheric lens coincides with the capsule boundaries. The capsule thickness is proportional to the distance between successive peaks. Anterior and posterior lens capsule thickness measurements were performed on 13 human, 10 monkey, and 34 New Zealand white rabbit lenses. The cadaver eyes were prepared for optical measurements by bonding a PMMA ring on the sclera. The posterior pole was sectioned, excess vitreous was removed, and the eye was placed on a Teflon slide. The cornea and iris were then sectioned. After the experiments, the lenses were excised, placed in 10% buffered formalin, and prepared for histology. Results: Central anterior lens capsule thickness was 9.4+/-2.9μm (human), 11.2+/-6.6μm (monkey), and 10.3+/-3.6μm (rabbit) optically and 14.9+/-1.6μm (human), 17.7+/-4.9μm (monkey), and 12.6+/-2.3μm (rabbit) histologically. The values for the central posterior capsule were 9.4+/-2.9μm (human), 6.6+/-2.5μm (monkey), and 7.9+/-2.3μm (rabbit) optically and 4.6+/-1.4μm (human), 4.5+/-1.2μm (monkey), and 5.7+/-1.7μm (rabbit) histologically. Conclusions: This study demonstrates that a non-contact optical system can successfully measure lens capsule thickness in cadaver eyes.

  13. [Research Progress of Vitreous Humor Detection Technique on Estimation of Postmortem Interval].

    Science.gov (United States)

    Duan, W C; Lan, L M; Guo, Y D; Zha, L; Yan, J; Ding, Y J; Cai, J F

    2018-02-01

    Estimation of postmortem interval (PMI) plays a crucial role in forensic study and identification work. Because of the unique anatomy location, vitreous humor is considered to be used for estima- ting PMI, which has aroused interest among scholars, and some researches have been carried out. The detection techniques of vitreous humor are constantly developed and improved which have been gradually applied in forensic science, meanwhile, the study of PMI estimation using vitreous humor is updated rapidly. This paper reviews various techniques and instruments applied to vitreous humor detection, such as ion selective electrode, capillary ion analysis, spectroscopy, chromatography, nano-sensing technology, automatic biochemical analyser, flow cytometer, etc., as well as the related research progress on PMI estimation in recent years. In order to provide a research direction for scholars and promote a more accurate and efficient application in PMI estimation by vitreous humor analysis, some inner problems are also analysed in this paper. Copyright© by the Editorial Department of Journal of Forensic Medicine.

  14. Removal of giant intraocular foreign body with the assistance of silicone oil tamponade in 23G vitrectomy

    Directory of Open Access Journals (Sweden)

    Zhong-Ping Chen

    2018-01-01

    Full Text Available AIM: To evaluate the outcomes and safety of minimally invasive 23G pars plana vitrectomy(PPVcombined with silicone oil tamponade for the removal of giant intraocular foreign body(IOFB. METHODS: A total of 12 cases diagnosed with giant IOFB were included in this retrospective study in which 11 eyes of 11 males and 1 eye of 1 female were treated in Changsha Aier Eye Hospital between February 2012 and March 2015. Among these patients, the preoperative best corrected visual acuity varied from light perception to 0.1 with retinal detachment identified in all 12 eyes. All patients underwent 23G minimally invasive PPV. After the vitreous was removed and the damaged retina was repaired, silicone oil was filled, and then the scleral incision was extended to remove the giant IOFB. Lens extraction and intraocular lens implantation were performed in some patients when necessary. Silicone oil was removed 6mo later. RESULTS: The giant IOFB was removed successfully just with 1 attempt in each of 12 eyes, and no IOFB fell and reinjured the retina or damaged the cornea during the procedure. All retinas were reattached and no endophthalmitis was observed in any patients postoperatively. The silicone oil was removed successfully after 6mo, and by then the visual acuity was improved in all cases. Sixty-seven percent of patients became free of blindness and 25% free of visual disability. CONCLUSION: Removing giant IOFB through 23G PPV assisted with silicone oil tamponade is safe and effective.

  15. Pathological findings in the lens capsules and intraocular lens in chronic pseudophakic endophthalmitis: an electron microscopy study.

    Science.gov (United States)

    Adán, A; Casaroli-Marano, R P; Gris, O; Navarro, R; Bitrian, E; Pelegrin, L; Sanchez-Dalmau, B

    2008-01-01

    The aim of this study was to describe the pathological findings in lens capsules and intraocular lens (IOL) studied by scanning and/or transmission electron microscopy (SEM and TEM, respectively) in a series of four eyes with chronic pseudophakic endophthalmitis (CPE). We performed a retrospective study of four patients presenting CPE in whom surgical treatment with pars plana vitrectomy, capsulectomy with extraction of the IOL, and intravitreous antibiotic therapy was thereafter performed. The extracted IOL and the capsular remains were studied by SEM and/or TEM and microbiologic analysis of aqueous humour and vitreous aspirate was also carried out in all the cases. The presence of microorganisms was observed in the material analysed in all the cases studied. The use of TEM identified bacterial contamination by Staphylococcus spp and mixed contamination with microorganisms presenting a bacillar morphology suggestive of infection by Propionibacterium acnes in addition to the presence of cocci in the capsular remains. In another two cases, SEM localized colonies of Staphylococcus spp on the surface of the IOL in one case and mixed bacterial colonization with cocci plus filamentous bacteria in the other. The presence of macrophages associated with bacteria was observed in the capsular remains. Microorganisms were found in the IOL or the capsular material in the four cases studied, thereby explaining the refractoriness and severity of infection. The possible presence of polymicrobial infections, especially in the cases with filamentous bacteria, also explains the recurrence of infection.

  16. Clinical observation on vitreous surgery in treating idiopathic macular hole

    Directory of Open Access Journals (Sweden)

    Min Liu

    2013-12-01

    Full Text Available AIM: To observe the surgical effect and influential factors of idiopathic macular hole(IMHtreated with vitrectomy and internal limiting membrane peeling combined with intravitreal gas tamponade.METHODS: The clinical data of 22 IMH patients(23 eyeswere retrospectively analyzed. All the patients were diagnosed with IMH by optical coherence tomography(OCTand their macular hole patterns were measured before and after surgery by OCT in addition to the routine examinations. All patients were treated with vitrectomy, internal limiting membrane peeling combined with gas injection(air or inert gas. The postoperative visual acuity, macular hole closure rate and the incidence of surgical complications were observed. The correlation between the patients' age, course of disease, preoperative best corrected visual acuity(BCVA, macular hole diameter, the type of vitreous cavity filling gas, the postoperative BCVA, and the macular hole closure rate was analyzed with SPSS 13.0 statistical software.RESULTS: Postoperative OCT examination results showed that the macular hole closure rate was 100%. The macular hole closure rate was 79%(11 eyes of 14 eyesafter the first intravitreal air injection and 100%(9 eyesafter fist intravitreal inert gas injection(100mL/L C3F8. There was no significant difference between the air injection and inert gas injection(χ2=2.1214, P>0.05. The mean preoperational BCVA was 0.11±0.05 and the mean postoperative BCVA 0.23±0.12; there was a statistically significant difference between them(t=4.023,Pt=3.92, PPr=-0.415, P=0.256, duration of disease(r=0.193, P= 0.498, preoperative VA(r=0.152, P=0.673had no significant influence on IMH visual outcomes.CONCLUSION: The vitrectomy combined with internal limiting membrane peeling and intravitreal gas tamponade is an effective treatment for IMH; the macular hole diameter is the major influence factor in the postoperative closure and visual prognosis of IMH; while the preoperative visual acuity

  17. [Correct contact lens hygiene].

    Science.gov (United States)

    Blümle, S; Kaercher, T; Khaireddin, R

    2013-06-01

    Although contact lenses have long been established in ophthalmology, practical aspects of handling contact lenses is becoming increasingly less important in the clinical training as specialist for ophthalmology. Simultaneously, for many reasons injuries due to wearing contact lenses are increasing. In order to correct this discrepancy, information on contact lenses and practical experience with them must be substantially increased from a medical perspective. This review article deals with the most important aspects for prevention of complications, i.e. contact lens hygiene.

  18. Genetic analysis of vitreous endosperms derived from homozygotic plants for opaque-2 gene in maize (Zea mays L.)

    International Nuclear Information System (INIS)

    Prioli, A.J.; Barbosa, H.M.; Sant'Anna, R.

    1980-01-01

    From experiments in which opaque-2 maize seeds were treated with gamma rays and ethil methanesulfonate, and their respective untreated controls, seeds with hard, vitreous endosperms were obtained. Some of these were completely vitreous, with no evidence of opaque endosperm tissue. Others had very small and few (one to three) areas of opaque tissue. Plants derived from completely vitreous endosperm seeds were self pollinated and crossed to an opaque-2 inbred. The segregation of vitreous to opaque seeds indicated that the normal allele at the opaque-2 locus was responsible for the vitreousity of the endosperm. Lysine content of the vitreous endosperm was comparable to that of normal endosperms. Plants derived from vitreous seeds with few and tiny spots of opaque tissue produced, upon selfing or crossing to the opaque-2 inbred, only opaque-2 seeds. It is concluded that: (a) induced mutation may not be an effective tool to obtain vitreous opaque-2 endosperm with high lysine content; and, (b) there are unknown genetic systems which severely modify the expression of the opaque-2 gene. (Author) [pt

  19. VITREOUS INCARCERATION IN SCLEROTOMIES AFTER VALVED 23-, 25-, OR 27-GAUGE AND NONVALVED 23- OR 25-GAUGE MACULAR SURGERY.

    Science.gov (United States)

    Tosi, Gian Marco; Malandrini, Alex; Cevenini, Gabriele; Neri, Giovanni; Marigliani, Davide; Cerruto, Arianna; Virgili, Gianni

    2017-10-01

    To study the patterns of vitreous incarceration at sclerotomy sites by ultrasound biomicroscopy in patients subjected to valved or nonvalved small-gauge pars plana vitrectomy. A prospective comparative study of 88 eyes affected by epiretinal membrane and macular hole. Patients were divided into four groups: valved or nonvalved 23-gauge (16 eyes each) and valved or nonvalved 25-gauge (20 eyes each); their vitreal disposition was compared by ultrasound biomicroscopy. Vitreal disposition was also assessed in 16 eyes of 16 patients subjected to valved 27-gauge pars plana vitrectomy. Three vitreal patterns were identified: P0 (vitreous not visible or vitreous strand distant from the sclerotomy site), P1 (vitreous strand parallel to and in contact with the sclerotomy site), and P2 (vitreous strand entrapped in the sclerotomy site). The effect of valved trocar use on vitreous incarceration seemed to be somewhat beneficial, but no statistically significant effect could be shown (odds ratio: 0.85, 95% confidence interval: 0.42-1.74, P = 0.657). Similarly, no differences in vitreous incarceration were shown among vitrectomy gauges (23, 25, or 27) both in a model including valved trocars only (P = 0.858) and in a model with all available data (P = 0.935). In 23- and 25-gauge macular surgeries, postoperative vitreous incarceration does not seem to be reduced using valved cannulas and was similar to that observed in 27-gauge surgery.

  20. Integrating Micro- or Nanoscale Encapsulation Technology with Vitreous Cryopreservation: A New Strategy to Improve Biopreservation.

    Science.gov (United States)

    Zheng, Y Y; Zhao, G

      BACKGROUND: None-uniform distributions of temperatures, limited freezing and thawing rates, and thermal stresses are three main hindering factors for successful vitreous cryopreservation of mass volume of biosamples. Micro- and nanoscale encapsulation, owning the intrinsic features to avoid those limitations introduced by the traditional approaches, has been opened up a new way for effective and high-efficiency biopreservation. This short review article summarizes recent advances in cell encapsulation technology for biopreservation by manipulating cells and biological agents in micro- or nanoscale volume droplets and microgels, and discusses its promising applications for future vitreous cryopreservation.

  1. Vitreous-induced cytoskeletal rearrangements via the Rac1 GTPase-dependent signaling pathway in human retinal pigment epithelial cells

    International Nuclear Information System (INIS)

    Huang, Xionggao; Wei, Yantao; Ma, Haizhi; Zhang, Shaochong

    2012-01-01

    Highlights: ► Vitreous induces morphological changes and cytoskeletal rearrangements in RPE cells. ► Rac1 is activated in vitreous-transformed RPE cells. ► Rac inhibition prevents morphological changes in vitreous-transformed RPE cells. ► Rac inhibition suppresses cytoskeletal rearrangements in vitreous-transformed RPE cells. ► The vitreous-induced effects are mediated by a Rac1 GTPase/LIMK1/cofilin pathway. -- Abstract: Proliferative vitreoretinopathy (PVR) is mainly caused by retinal pigment epithelial (RPE) cell migration, invasion, proliferation and transformation into fibroblast-like cells that produce the extracellular matrix (ECM). The vitreous humor is known to play an important role in PVR. An epithelial-to-mesenchymal transdifferentiation (EMT) of human RPE cells induced by 25% vitreous treatment has been linked to stimulation of the mesenchymal phenotype, migration and invasion. Here, we characterized the effects of the vitreous on the cell morphology and cytoskeleton in human RPE cells. The signaling pathway that mediates these effects was investigated. Serum-starved RPE cells were incubated with 25% vitreous, and the morphological changes were examined by phase-contrast microscopy. Filamentous actin (F-actin) was examined by immunofluorescence and confocal microscopy. Protein phosphorylation of AKT, ERK1/2, Smad2/3, LIM kinase (LIMK) 1 and cofilin was analyzed by Western blot analysis. Vitreous treatment induced cytoskeletal rearrangements, activated Rac1 and enhanced the phosphorylation of AKT, ERK1/2 and Smad2/3. When the cells were treated with a Rac activation-specific inhibitor, the cytoskeletal rearrangements were prevented, and the phosphorylation of Smad2/3 was blocked. Vitreous treatment also enhanced the phosphorylation of LIMK1 and cofilin and the Rac inhibitor blocked this effect. We propose that vitreous-transformed human RPE cells undergo cytoskeletal rearrangements via Rac1 GTPase-dependent pathways that modulate LIMK1 and

  2. Vitreous-induced cytoskeletal rearrangements via the Rac1 GTPase-dependent signaling pathway in human retinal pigment epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xionggao [State Key Ophthalmic Laboratory, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou (China); Department of Ophthalmology, Hainan Medical College, Haikou (China); Wei, Yantao; Ma, Haizhi [State Key Ophthalmic Laboratory, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou (China); Zhang, Shaochong, E-mail: zhshaochong@163.com [State Key Ophthalmic Laboratory, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou (China)

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer Vitreous induces morphological changes and cytoskeletal rearrangements in RPE cells. Black-Right-Pointing-Pointer Rac1 is activated in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition prevents morphological changes in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition suppresses cytoskeletal rearrangements in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer The vitreous-induced effects are mediated by a Rac1 GTPase/LIMK1/cofilin pathway. -- Abstract: Proliferative vitreoretinopathy (PVR) is mainly caused by retinal pigment epithelial (RPE) cell migration, invasion, proliferation and transformation into fibroblast-like cells that produce the extracellular matrix (ECM). The vitreous humor is known to play an important role in PVR. An epithelial-to-mesenchymal transdifferentiation (EMT) of human RPE cells induced by 25% vitreous treatment has been linked to stimulation of the mesenchymal phenotype, migration and invasion. Here, we characterized the effects of the vitreous on the cell morphology and cytoskeleton in human RPE cells. The signaling pathway that mediates these effects was investigated. Serum-starved RPE cells were incubated with 25% vitreous, and the morphological changes were examined by phase-contrast microscopy. Filamentous actin (F-actin) was examined by immunofluorescence and confocal microscopy. Protein phosphorylation of AKT, ERK1/2, Smad2/3, LIM kinase (LIMK) 1 and cofilin was analyzed by Western blot analysis. Vitreous treatment induced cytoskeletal rearrangements, activated Rac1 and enhanced the phosphorylation of AKT, ERK1/2 and Smad2/3. When the cells were treated with a Rac activation-specific inhibitor, the cytoskeletal rearrangements were prevented, and the phosphorylation of Smad2/3 was blocked. Vitreous treatment also enhanced the phosphorylation of LIMK1 and cofilin and the Rac inhibitor blocked this effect. We propose that vitreous

  3. Prolonging contact lens wear and making contact lens wear safer.

    Science.gov (United States)

    Foulks, Gary N

    2006-02-01

    To summarize the present status of safety and efficacy of contact lens wear. Literature review. Ovid Medline searches were performed on records from 1966 through 2005 using keywords: keratitis, contact lens complications, extended-wear contact lenses, and silicone-hydrogel contact lenses. Patients desire comfort, clarity of vision, and prolonged contact lens wear when contact lenses are used to correct refractive error. Practitioners desire patient satisfaction but also require maintenance of the integrity of the eye and no complications that jeopardize vision or health of the eye. Improvements in the oxygen permeability of the contact lens materials, design of the contact lens and its surface, and solutions for the maintenance of the lens have reduced but not eliminated the risks of infection, inflammation, and conjunctival papillary reaction associated with contact lens wear. The lessons of past and recent history suggest that patient education and practitioner participation in the management of contact lens wear continue to be critical factors for patient satisfaction and safety in the extended wear of contact lenses. The availability of highly oxygen permeable contact lenses has increased the tolerance and safety of extended contact lens wear, but patient instruction and education in proper use and care of lenses is required and caution is advised.

  4. Development of a Fresnel lens for cold neutrons based on neutron refractive optics

    CERN Document Server

    Oku, T; Moriyasu, S; Yamagata, Y; Ohmori, H; Takizawa, Y; Shimizu, H M; Hirota, T; Kiyanagi, Y; Ino, T; Furusaka, M; Suzuki, J

    2001-01-01

    We have developed compound refractive lenses (CRLs) for cold neutrons, which are made of vitreous silica and have an effective potential of (90.1-2.7x10 sup - sup 4 i) neV. In the case of compound refractive optics, neutron absorption by the material deteriorates lens performance. Thus, to prevent an increase in neutron absorption with increasing beam size, we have developed Fresnel lenses using the electrolytic in-process dressing grinding technique. The lens characteristics were carefully investigated with experimental and numerical simulation studies. The lenses functioned as a neutron focusing lens, and the focal length of 14 m was obtained with a 44-element series of the Fresnel lenses for 10 A neutrons. Moreover, good neutron transmission of 0.65 for 15 A neutrons was obtained due to the shape effect. According to comprehensive analysis of the obtained results, it is possible to realize a CRL for practical use by choosing a suitable lens shape and material.

  5. Lens-sparing vitrectomy for shaken baby syndrome

    Directory of Open Access Journals (Sweden)

    Fiona Chew Lee Min

    2016-02-01

    Full Text Available AIM: To document the ophthalmological findings and visual outcomes for shaken baby syndrome(SBSpatients who had lens-sparing vitrectomy(LSVfor non-resolving premacular and vitreous hemorrhages obscuring the macula.METHODS: A retrospective review and statistical analysis of ophthalmological and demographic data of patients admitted with SBS from 2010 to 2012 was done. Patients with premacular and vitreous hemorrhage obscuring the macula who underwent LSV were included as subjects. Paired samples t-test was used to compare means, categorical data was analysed using Fisher's exact test and Pearson Chi-squared test. P value of less than 0.05 was considered as statistically significant.RESULTS: Thirty two subjects were recruited with a mean age of 5.09±1.96mo. Twenty one(65.6%subjects had visual acuity of no light perception at presentation. Subjects with poorer initial visual acuity had larger pupil sizes(P=0.021and most of them had neurosurgical intervention(P=0.027. The mean duration to perform LSV was 28.56±20.83d. Our vitrectomy complication rate was 4.26%. Post-operatively, 26(80%subjects had vision of light perception or better, the spherical equivalent was significantly more myopic(P=0.001.CONCLUSION: Prompt ophthalmological assessment is vital to ensure optimum visual rehabilitation in SBS patients. With low complication rates, early surgical intervention with LSV represents a promising option for non-resolving intraocular hemorrhages obscuring the macula in SBS.

  6. Sapphire ball lens-based fiber probe for common-path optical coherence tomography and its applications in corneal and retinal imaging.

    Science.gov (United States)

    Zhao, Mingtao; Huang, Yong; Kang, Jin U

    2012-12-01

    We describe a common-path swept source optical coherence tomography fiber probe design using a sapphire ball lens for cross-sectional imaging and sensing for retina vitrectomy surgery. The high refractive index (n=1.75) of the sapphire ball lens improves the focusing power and enables the probe to operate in the intraocular space. The highly precise spherical shape of the sapphire lens also reduces astigmatism and coma compared to fused nonspherical ball lenses. A theoretical sensitivity model for common-path optical coherence tomography (CP-OCT) was developed to assess its optimal performance based on an unbalanced photodetector configuration. Two probe designs-with working distances 415 and 1221 μm and lateral resolution 11 and 18 μm-were implemented with sensitivity up to 88 dB, which is significantly higher than previously reported CP-OCT probes. We assessed the performances of the fiber probes by cross-sectional imaging a bovine cornea and retina in air and in vitreous gel with a 1310 nm swept source OCT system. To the best of our knowledge, this is the first demonstration of sapphire ball lens-based CP-OCT probes directly inserted into the vitreous gel of a bovine eyeball for ocular imaging with a sensitivity approaching the theoretical limitation of CP-OCT.

  7. Intraocular Lens Subluxation in Marfan Syndrome

    Science.gov (United States)

    Rodrigo, Bolaños-Jiménez; Paulina, López-Lizárraga E; Francesc, March de R; Eduardo, Telich-Tarriba J; Alejandro, Navas

    2014-01-01

    Purpose : Ectopia lentis (EL) is a major criteria for the diagnosis of Marfan syndrome, it may vary from an asymptomatic mild displacement to a significant subluxation that places the equator of the lens in the pupillary axis. The purpose of this work is to present the case of a patient with Marfan syndrome who received treatment for subluxation at our institution. Case Report : A 51-year-old female diagnosed with Marfan syndrome presented to the emergency department with bilateral eye redness, foreign body sensation and crusting around the eyes on awakening. She had the following history of cardiac and ophthalmologic complications, including: 1. Lens subluxation 2. High myopia 3. Aortic root dilation, 4. Mitral valve prolapse and 5. Tricuspid insufficiency. Conclusion : The ophthalmological management of Marfan patients is challenging and periodical follow-up is needed. Surgical versus conservative management is controversial, each case needs to be evaluated individually to analyze the risks and benefits of the procedures. PMID:25279020

  8. [Clinical study of the auxiliary management with iris retractor for subluxated lens combined with cataract].

    Science.gov (United States)

    Zhong, Liu-Xueying; Zheng, Dan-Ying; Sun, Yi

    2011-01-01

    To study the clinical effects and safety of the auxiliary management with iris retractor for subluxated lens combined with cataract. Thirty-one eyes lens subluxation with cataract come from 27 patients were reviewed, all of them were 30 - 78 years old and III - IV grade of nuclear. Among these patients, 14 were traumatic cataracts, 12 Marfan syndromes, two over-mature phase of cataracts, one caused suspensory ligament broken during phacoemulsification, and one unclear reason. 1 to 4 iris retractors were used during surgeries, according to the extension of zonular loss and nuclear hardness. Anterior vitrectomy would be taken if vitreous prolapsed. Visual acuities and reactions post-operative were observed, too. And correlation analysis would be used to study the relationship of those objections. There were no serious complications during the surgeries such as tearing of capsular, falling of nuclear, bleeding of intraocular, and so on. Only 9 of 31 eyes (29.0%) had vitreous prolapsed interoperation, which appeared a significant correlated with range of zonular loss (Spearman r = 0.453, P = 0.010). However, none of them happened during the phacoemulsification for lens nucleus and only 6 eyes took the anterior vitrectomy. The best corrected postoperative visual acuity of these patients attended to 0.2 - 1.2 at a half to 1 month, increased by 1 - 12 lines [average of (6.0 ± 2.7) lines] compared with preoperative. Twenty-three eyes visual acuity of them were no less than 0.5. Corneal edema postoperatively appeared a significant correlated with vitrectomy (Spearman r = 0.398, P = 0.026), while seemed no associated with the range of zonular loss, the number of iris retractors, energy and duration of ultrasound burst or type of intraocular lens (IOL) (P > 0.05). Phacoemulsification assists with iris retractor can simplify the process of cataract surgery of subluxated lens. Individualized surgical planning and flexible and decisive measures intra-operative achieved good

  9. Lens subluxation grading system: predictive value for ectopia lentis surgical outcomes

    Directory of Open Access Journals (Sweden)

    Mauro Waiswol

    2009-03-01

    Full Text Available Objective: To present a classification system to grade ectopia lentis and to assess its usefulness as a predictor for surgical outcomes. Methods: Fifty-one eyes of 28 patients with either simple (19 patients or Marfan syndrome-associated ectopia lentis (nine patients with variable degrees of subluxation were operated on. Lens subluxation intensity was graded according to the lens subluxation grading system (LSGS from grade 1 (lens on the whole pupillary area up to grade 4 (lens absent from the pupillary area. Thirty eyes underwent cataract extraction (“dry” aspiration with endocapsular ring and in-the-bag intraocular lens (IOL implantation. Twenty-one eyes underwent cataract extraction (“dry” aspiration with scleral fixation of the IOL. The predictive value of the LSGS was assessed by analyzing the post-operative outcomes, including visual acuity (VA, endothelial cell loss, and complications for each grade on the grading system. Rresults: Patients were classified into grade 1 (19.6%, grade 2 (51% and grade 3 (29.4%. Post-operative VA was lower for eyes with larger degrees of subluxation. The higher the subluxation grade, the higher the endothelial cell loss, as well as, the frequency of vitreous loss and surgical time. Higher subluxation grades prevented optimal surgical outcomes with endocapsular ring and in-the-bag IOL implantation. Cconclusions: The LSGS provides an estimate of the surgical success of ectopia lentis. Adequate standardization of lens subluxation is crucial for understanding studies dealing with the surgical correction of this disorder.

  10. Blood culture bottles are superior to conventional media for vitreous culture.

    Science.gov (United States)

    Thariya, Patsuda; Yospaiboon, Yosanan; Sinawat, Suthasinee; Sanguansak, Thuss; Bhoomibunchoo, Chavakij; Laovirojjanakul, Wipada

    2016-08-01

    To compare blood culture bottles and conventional media for the vitreous culture in patients with clinically suspected infectious endophthalmitis. Retrospective comparative study at KKU Eye Center, Khon Kaen University. There were 342 patients with clinically suspected infectious endophthalmitis participated in the study. The vitreous specimens were inoculated in both blood culture bottles and on conventional culture media (blood agar, MacConkey agar, chocolate agar, Sabouraud dextrose agar and thioglycolate broth). The number of positive culture yields in both blood culture bottles and conventional media. Positive culture yields in both methods were found in 151 eyes (49.5%). There were 136 of 151 eyes (90.1%) with positive culture in blood culture bottles, whereas 99 of 151 eyes (65.6%) yielded positive cultures in conventional media. These findings were different with a statistical significance (P culture bottles and conventional media improved the yield. Blood culture bottles are superior to conventional media for vitreous culture in clinically suspected infectious endophthalmitis. Vitreous culture using blood culture bottles should be recommended as the primary method for microbiological diagnosis. A combination of both methods further improves the positive culture yield. © 2016 Royal Australian and New Zealand College of Ophthalmologists.

  11. Reproducibility of vitreous fluorophotometry in patients with type 1 diabetes mellitus

    NARCIS (Netherlands)

    Jager, J; Tromp, A; Hooymans, JMM; Smit, AJ

    1997-01-01

    We assessed the day-to-day reproducible of vitreous fluorophotometry in 7 type 1 diabetic patients and in 1 healthy control subject. The coefficient of variation for duplicate measurements was 33.7, 40.3 and 23.6%, for the right eyes, the left eyes and mean values of both eyes, respectively.

  12. Diagnosis of ocular toxocariasis by detecting antibodies in the vitreous humor.

    Science.gov (United States)

    Inchauspe, S; Echandi, L V; Dodds, E M

    2018-02-02

    To demonstrate the production of the local toxocara antibodies in the vitreous of patients with negative serology. Retrospective review of the medical records of patients seen in a Tertiary Referral Hospital, and at an Eye Institute, with an ocular diagnosis of toxocariasis who had a negative serology and positive titres in the vitreous. After reviewing the medical records of 40 patients with a diagnosis of ocular toxocariasis, a total of six cases (15%) were found with a negative serology and a positive vitreous titre for toxocara antibody, both of them performed using an ELISA procedure. The mean age was 18 years, there were no differences observed between males and females. A peripheral granuloma was the most common clinic finding, and all patients underwent vitrectomy either to remove epiretinal membranes or to repair retinal detachments. A negative serology does not rule out a diagnosis of ocular toxocariasis. Vitreous samples may be necessary to confirm a clinical diagnosis. Copyright © 2018 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Packages of vitreous collagen (type II) in the human retina : an indication of postnatal collagen turnover?

    NARCIS (Netherlands)

    Ponsioen, TL; van der Worp, RJ; van Luyn, MJA; Hooymans, JMM; Los, LI

    The purpose of this study was to evaluate the vitreoretinal border in the (pre-)equatorial area in nonpathologic human donor eyes, because the majority of retinal defects induced by posterior vitreous detachment (PVD) are located there. Nine eyes (24-80 years) were fixed and embedded in Technovit

  14. Cyclic GMP in the pig vitreous and retina after experimental retinal detachment

    NARCIS (Netherlands)

    Diederen, R.; Heij, La E.C.; Lemmens, M.A.M.; Kijlstra, A.; Vente, De J.; Hendrikse, F.

    2008-01-01

    Purpose: Earlier studies have revealed a decreased level of cGMP in vitreous fluid obtained from patients with a retinal detachment. To further investigate this phenomenon, we developed an experimental retinal detachment model in pigs. Methods: Experimental unilateral retinal detachments were

  15. Experimental investigation of vitreous humour motion within a human eye model

    International Nuclear Information System (INIS)

    Repetto, Rodolfo; Stocchino, Alessandro; Cafferata, Chiara

    2005-01-01

    We present an experimental study of the vitreous motion induced by saccadic eye movements. A magnified model of the vitreous chamber has been employed, consisting of a spherical cavity carved in a perspex cylindrical container, which is able to rotate with a prescribed time law. Care has been taken to correctly reproduce real saccadic eye movements. The spherical cavity is filled with glycerol and the flow field is measured on the equatorial plane orthogonal to the axis of rotation, through the PIV technique. Visualizations of the fully three-dimensional flow suggest that it essentially occurs on planes perpendicular to the axis of rotation, the motion orthogonal to such planes being smaller by three to four orders of magnitude. Theoretical results, based on a simplified solution, are in very good agreement with the experimental findings. The maximum value of the shear stress at the wall, which is thought to play a possibly important role in the pathogenesis of retinal detachment, does not significantly depend on the amplitude of saccadic movements. This suggests that relatively small eye rotations, being much more frequent than large movements, are mainly responsible for vitreous stresses on the retina. Results also illustrate the dependence of the maximum shear stress at the wall from the vitreous viscosity

  16. Experimental investigation of vitreous humour motion within a human eye model

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, Rodolfo [Dipartimento di Ingegneria delle Strutture, delle Acque e del Terreno, University of L' Aquila (Italy); Stocchino, Alessandro [Dipartimento di Ingegneria Ambientale, University of Genova (Italy); Cafferata, Chiara [Dipartimento di Ingegneria Ambientale, University of Genova (Italy)

    2005-10-07

    We present an experimental study of the vitreous motion induced by saccadic eye movements. A magnified model of the vitreous chamber has been employed, consisting of a spherical cavity carved in a perspex cylindrical container, which is able to rotate with a prescribed time law. Care has been taken to correctly reproduce real saccadic eye movements. The spherical cavity is filled with glycerol and the flow field is measured on the equatorial plane orthogonal to the axis of rotation, through the PIV technique. Visualizations of the fully three-dimensional flow suggest that it essentially occurs on planes perpendicular to the axis of rotation, the motion orthogonal to such planes being smaller by three to four orders of magnitude. Theoretical results, based on a simplified solution, are in very good agreement with the experimental findings. The maximum value of the shear stress at the wall, which is thought to play a possibly important role in the pathogenesis of retinal detachment, does not significantly depend on the amplitude of saccadic movements. This suggests that relatively small eye rotations, being much more frequent than large movements, are mainly responsible for vitreous stresses on the retina. Results also illustrate the dependence of the maximum shear stress at the wall from the vitreous viscosity.

  17. The rabbit as an animal model for post-natal vitreous matrix differentiation and degeneration

    NARCIS (Netherlands)

    Los, L. I.

    2008-01-01

    Purpose This study evaluates whether rabbits are a suitable animal model to study post-natal vitreous differentiation and degeneration. Methods Human and rabbit eyes of various ages were studied by complementary anatomical techniques, light microscopy, and transmission electron microscopy. Results

  18. Catecholamines and their O-methylated metabolites in vitreous humor in hypothermia cases.

    Science.gov (United States)

    Hervet, Tania; Teresiński, Grzegorz; Hejna, Petr; Descloux, Emilienne; Grouzmann, Eric; Palmiere, Cristian

    2016-06-01

    The aim of this study was to assess the diagnostic value of catecholamines and their O-methylated metabolites in vitreous humor samples in identifying antemortem cold exposure and fatal hypothermia in the forensic casework. A total of 80 autopsy cases (40 hypothermia fatalities and 40 cases in which hypothermia as the main or contributory cause of death was excluded) were selected for this study. Catecholamines and their O-methylated metabolites were measured in urine and vitreous humor samples collected at autopsy. Urine catecholamine and their O-methylated metabolite concentrations were significantly higher in hypothermia-related deaths. On the other hand, measurements in vitreous humor samples did not reveal statistically significant differences between hypothermia-related deaths and controls. Globally considered, our findings seem to suggest that, contrary to urine catecholamines and their O-methylated metabolites, vitreous levels of these compounds appear to be of limited value in characterizing human antemortem stress reactions due to cold exposure and can hardly be used in the forensic setting to support the diagnosis of hypothermia.

  19. Proliferative and inflammatory factors in the vitreous of patients with proliferative diabetic retinopathy

    Directory of Open Access Journals (Sweden)

    V V Chernykh

    2015-01-01

    Full Text Available Purpose: The purpose was to measure the concentrations of various cytokines and growth factors (including vascular endothelial growth factor [VEGF] and pigment epithelium-derived factor [PEDF] in the vitreous of patients with proliferative diabetic retinopathy (PDR and to investigate interaction between inflammatory and proliferative factors in the genesis of PDR. Materials and Methods : Vitreous samples from 32 eyes with PDR and 25 eyes without diabetes mellitus and signs of DR (control were collected. Vitreous concentrations of VEGF, PEDF, monocyte chemotactic protein-1 (MCP-1, interleukin-4 (IL-4, IL-6, IL-8, IL-10, IL-17A, and secretory immunoglobulin A (sIgA were simultaneously measured using enzyme-linked immunoassay. Results : Vitreous levels of VEGF, PEDF, IL-17A, IL-6, IL-8, IL-4, and sIgA were significantly (Π < 0.05 higher in eyes with PDR compared to control. The concentration of VEGF was more than 17-times higher than in control, and the concentration of PEDF was not changed oppositely and was also higher (1.45-times compared to control, that may indicate disturbances of compensatory mechanisms in angiogenesis regulation in PDR. Significant (Π < 0.05 positive correlations were observed between vitreous concentrations of VEGF and IL-17ΐ (r = 0.45, VEGF and IL-8 (r = 0.48, VEGF and IL-4 (r = 0.51, PEDF and IL-17ΐ (r = 0.48, PEDF and IL-8 (r = 0.59, MCP-1 and PEDF (r = 0.72, MCP-1 and IL-8 (r0 = 0.45, IL-4 and IL-17ΐ (r = 0.65, IL-4 and IL-8 (r = 0.71, IL-8 and IL-17ΐ (r = 0.59. Conclusions: Significantly raised levels of inflammatory and proliferative factors and numerous positive correlations between them may demonstrate a significant role of activation of vascular proliferation and local inflammation in the pathogenesis of PDR.

  20. Cyclic GMP in the pig vitreous and retina after experimental retinal detachment.

    Science.gov (United States)

    Diederen, Roselie M H; La Heij, Ellen C; Lemmens, Marijke A M; Kijlstra, Aize; de Vente, Jan; Hendrikse, Fred

    2008-02-04

    Earlier studies have revealed a decreased level of cGMP in vitreous fluid obtained from patients with a retinal detachment. To further investigate this phenomenon, we developed an experimental retinal detachment model in pigs. Experimental unilateral retinal detachments were induced in pig eyes by subretinal injection of 0.25% sodium hyaluronate. Fourteen days later the vitreous and retinas were analyzed for cGMP expression. Following enucleation, the retinas were incubated in the presence of a nonselective phosphodiesterase inhibitor (IBMX), and the particulate guanylyl cyclase stimulator atrial natriuretic peptide (ANP) or the soluble guanylyl cyclase stimulator sodium nitroprusside (SNP). cGMP was visualized in retinal wholemounts by immunochemistry combined with a computer based stereology system. cGMP levels in vitreous were determined by ELISA. The mean vitreous cGMP level in pig eyes with a retinal detachment (1.45 pmol/ml) was significantly lower compared to the mean level of cGMP in healthy pig eyes (4.61 pmol/ml; p=0.028 was considered significant). In the inner retina, ANP as well as SNP induced cGMP immunoreactivity in both detached and healthy retinas. After incubation with ANP, cGMP could also be detected in the outer nuclear layer of the detached retina, whereas this was not the case in the normal retina. Experimental retinal detachment in the pig eye leads to a decrease of cGMP levels in vitreous similar to that observed in clinical studies. This model may be helpful to analyze the mechanisms involved in cGMP dynamics following retinal detachment.

  1. Compliance among soft contact lens wearers.

    OpenAIRE

    Kuzman, Tomislav; Barišić Kutija, Marija; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurišić, Darija; Škegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-01-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in ...

  2. Panoramic lens applications revisited

    Science.gov (United States)

    Thibault, Simon

    2008-04-01

    During the last few years, innovative optical design strategies to generate and control image mapping have been successful in producing high-resolution digital imagers and projectors. This new generation of panoramic lenses includes catadioptric panoramic lenses, panoramic annular lenses, visible/IR fisheye lenses, anamorphic wide-angle attachments, and visible/IR panomorph lenses. Given that a wide-angle lens images a large field of view on a limited number of pixels, a systematic pixel-to-angle mapping will help the efficient use of each pixel in the field of view. In this paper, we present several modern applications of these modern types of hemispheric lenses. Recently, surveillance and security applications have been proposed and published in Security and Defence symposium. However, modern hemispheric lens can be used in many other fields. A panoramic imaging sensor contributes most to the perception of the world. Panoramic lenses are now ready to be deployed in many optical solutions. Covered applications include, but are not limited to medical imaging (endoscope, rigiscope, fiberscope...), remote sensing (pipe inspection, crime scene investigation, archeology...), multimedia (hemispheric projector, panoramic image...). Modern panoramic technologies allow simple and efficient digital image processing and the use of standard image analysis features (motion estimation, segmentation, object tracking, pattern recognition) in the complete 360° hemispheric area.

  3. Shape change of the vitreous chamber influences retinal detachment and reattachment processes: is mechanical stress during eye rotations a factor?

    Science.gov (United States)

    Meskauskas, Julia; Repetto, Rodolfo; Siggers, Jennifer H

    2012-09-19

    We aim to understand how mechanical causation influences retinal detachment and reattachment processes. In particular, myopes suffer retinal detachment more frequently than emmetropes, and following a retinal detachment, scleral buckling promotes retinal reattachment. We test the hypothesis that stresses arising from saccadic eye rotations are involved in the processes, and that the alteration in the stress due to the change in the vitreous chamber geometry is sufficient to explain the phenomena. The vitreous chamber of the eye has an approximately spherical shape and it is filled with vitreous humor. We developed a mathematical model, treating the vitreous chamber in emmetropic and myopic eyes as a spheroid and in eyes subjected to scleral buckling as a sphere with a circumferential indentation. We assume that the eye performs prescribed small-amplitude, periodic, torsional rotations and we solve semi-analytically for the fluid pressure, velocity, and stress distributions. The shape of the vitreous chamber has a large effect on the retinal stress. The vitreous and the retina of a highly myopic eye continuously experience shear stresses significantly higher than those of an emmetropic eye. An eye fitted with a scleral buckle experiences large stress levels localized around the buckle. Our results provide a mechanical explanation for the more frequent occurrence of posterior vitreous detachment and retinal detachment in myopic eyes. To understand how the stress distribution in a buckled eye facilitates reattachment, an additional model of the details of the reattachment process should be coupled to this model.

  4. Elevated Levels of Cytokines Associated with Th2 and Th17 Cells in Vitreous Fluid of Proliferative Diabetic Retinopathy Patients.

    Directory of Open Access Journals (Sweden)

    Masaru Takeuchi

    Full Text Available Macrophages are involved in low-grade inflammation in diabetes, and play pathogenic roles in proliferative diabetic retinopathy (PDR by producing proinflammatory cytokines. T cells as well as other cells are also activated by proinflammatory cytokines, and infiltration into the vitreous of patients with PDR has been shown. In this study, we measured helper T (Th cell-related cytokines in the vitreous of PDR patients to define the characteristics of Th-mediated immune responses associated with PDR. The study group consisted of 25 type 2 diabetic patients (25 eyes with PDR. The control group consisted of 27 patients with epiretinal membrane (ERM, 26 patients with idiopathic macular hole (MH, and 26 patients with uveitis associated with sarcoidosis. Vitreous fluid was obtained at the beginning of vitrectomy, and centrifuging for cellular removals was not performed. Serum was also collected from PDR patients. IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, soluble sCD40L, and TNFα in the vitreous and serum samples were measured. Both percent detectable and levels of IL-4, IL-6, IL-17A, IL-21, IL-22, and TNFα in the vitreous were significantly higher than those in the serum in PDR patients. Vitreous levels of these cytokines and IL-31 were significantly higher in PDR than in ERM or MH patients. Vitreous levels of IL-4, IL-17A, IL-22, IL-31, and TNFα in PDR patients were also significantly higher than those of sarcoidosis patients. In PDR patients, vitreous IL-17A level correlated significantly with vitreous levels of IL-22 and IL-31, and especially with IL-4 and TNFα. Although it is unclear whether these cytokines play facilitative roles or inhibitory roles for the progression of PDR, the present study indicated that Th2- and Th17-related immune responses are involved in the pathogenesis of PDR.

  5. Multiple methods of surgical treatment combined with primary IOL implantation on traumatic lens subluxation/dislocation in patients with secondary glaucoma.

    Science.gov (United States)

    Wang, Rui; Bi, Chun-Chao; Lei, Chun-Ling; Sun, Wen-Tao; Wang, Shan-Shan; Dong, Xiao-Juan

    2014-01-01

    To describe clinical findings and complications from cases of traumatic lens subluxation/dislocation in patients with secondary glaucoma, and discuss the multiple treating methods of operation combined with primary intraocular lens (IOL) implantation. Non-comparative retrospective observational case series. 30 cases (30 eyes) of lens subluxation/dislocation in patients with secondary glaucoma were investigated which accepted the surgical treatment by author in the Ophthalmology of Xi'an No.4 Hospital from 2007 to 2011. According to the different situations of lens subluxation/dislocation, various surgical procedures were performed such as crystalline lens phacoemulsification, crystalline lens phacoemulsification combined anterior vitrectomy, intracapsular cataract extraction combined anterior vitrectomy, lensectomy combined anterior vitrectomy though peripheral transparent cornea incision, pars plana lensectomy combined pars plana vitrectomy, and intravitreal cavity crystalline lens phacofragmentation combined pars plana vitrectomy. And whether to implement trabeculectomy depended on the different situations of secondary glaucoma. The posterior chamber intraocular lenses (PC-IOLs) were implanted in the capsular-bag or trassclerally sutured in the sulus decided by whether the capsular were present. visual acuity, intraocular pressure, the situation of intraocular lens and complications after the operations. The follow-up time was 11-36mo (21.4±7.13). Postoperative visual acuity of all eyes were improved; 28 cases maintained IOP below 21 mm Hg; 2 cases had slightly IOL subluxation, 4 cases had slightly tilted lens optical area; 1 case had postoperative choroidal detachment; 4 cases had postoperative corneal edema more than 1wk, but eventually recovered transparent; 2 cases had mild postoperative vitreous hemorrhage, and absorbed 4wk later. There was no postoperative retinal detachment, IOL dislocation, and endophthalmitis. To take early treatment of traumatic lens

  6. Crystalline lens radioprotectors

    International Nuclear Information System (INIS)

    Belkacemi, Y.; Pasquier, D.; Castelain, B.; Lartigau, E.; Warnet, J.M.

    2003-01-01

    During more than a half of century, numerous compounds have been tested in different models against radiation-induced cataract. In this report, we will review the radioprotectors that have been already tested for non-human crystalline lens protection. We will focus on the most important published studies in this topic and the mechanisms of cyto-protection reported in. vitro and in. vivo from animals. The most frequent mechanisms incriminated in the cyto-protective effect are: free radical scavenging, limitation of lipid peroxidation, modulation of cycle progression increase of intracellular reduced glutathione pool, reduction of DNA strand breaks and limitation of apoptotic cell death. Arnifostine (or Ethyol) and anethole dithiolethione (or Sulfarlem), already used clinically as chemo- and radio-protectants, could be further test?r for ocular radioprotection particularly for radiation-induced cataract. (author)

  7. [Application of Mixed-effect Model in PMI Estimation by Vitreous Humor].

    Science.gov (United States)

    Yang, M Z; Li, H J; Zhang, T Y; Ding, Z J; Wu, S F; Qiu, X G; Liu, Q

    2018-02-01

    To test the changes of the potassium (K⁺) and magnesium (Mg²⁺) concentrations in vitreous humor of rabbits along with postmortem interval (PMI) under different temperatures, and explore the feasibility of PMI estimation using mixed-effect model. After sacrifice, rabbit carcasses were preserved at 5 ℃, 15 ℃, 25 ℃ and 35 ℃, and 80-100 μL of vitreous humor was collected by the double-eye alternating micro-sampling method at every 12 h. The concentrations of K⁺ and Mg²⁺ in vitreous humor were measured by a biochemical-immune analyser. The mixed-effect model was used to perform analysis and fitting, and established the equations for PMI estimation. The data detected from the samples that were stoned at 10 ℃, 20 ℃ and 30 ℃ with 20, 40 and 65 h were used to validate the equations of PMI estimation. The concentrations of K⁺ and Mg²⁺ [f( x , y )] in vitreous humor of rabbits under different temperature increased along with PMI ( x ). The relative equations of K⁺ and Mg²⁺ concentration with PMI and temperature under 5 ℃~35 ℃ were f K⁺ ( x , y )=3.413 0+0.309 2 x +0.337 6 y +0.010 83 xy -0.002 47 x ² ( P PMI estimation by K⁺ and Mg²⁺ was in 10 h when PMI was between 0 to 40 h, and the time of deviation was in 21 h when PMI was between 40 to 65 h. the ambient temperature range of 5 ℃-35 ℃, the mixed-effect model based on temperature and vitreous humor substance concentrations can provide a new method for the practical application of vitreous humor chemicals for PMI estimation. Copyright© by the Editorial Department of Journal of Forensic Medicine.

  8. Ultrasound monitoring of vitreous in pre and postLasik patients

    Directory of Open Access Journals (Sweden)

    Amanda Alvarado, MD

    2003-12-01

    Full Text Available Title: Echografic Vitreoretinal Findings afterLaser In Situ Keratomileusis.Objective: To report the echographic changesobserved in the vitreous of patients followingLasik. Design: Prospective, observational,descriptive study. Method: We performed anultrasound of the vitreous of patients elegiblefor refractive surgery. Vitreous Changes weremeasured by video B scan ultrasonographybefore and at the first and third month after Lasikat Fundación Oftalmológica Nacional betweenJune 2002 and March 2003. Results: A total of16 patients, 67% women, 33% men, mean ageof 31.6 years (range between 22 and 40 years.A total of 29 eyes were studied, 16 right and 13left for a total of 87 echographies. The refractiveerrors in a range of -10.50 and +3.50 of sphericalequivalent. There were 24 myopic and 5hypermetropic eyes. The vitreous changes correspondedto a posterior vitreous detachment(PVD and the presence of opacities in thevitreous. At the beginning of the study 18 eyes(62% had evidenced PVD and all of the 29 eyes(100% had opacities; At the end of the controls changes were evidenced in 22 eyes (81%, thevitreous opacities increased in 14 eyes (48.27%,while they remained without changes in 15 eyes(51.7%. The presence of newly developed PVDwas documented in 10 eyes (30 %, there was anincrease of PVD in 8 eyes (27.5%, and in onecase we observed the presence of a traction areaat the vitreoretinal interfase that correspondedto 3.4% of the eyes studied; it was an hypermetropicpatient in whom ophthalmoscopically,after the echographic findings, we evidenced twooperculated like retinal holes that requiredtreatment with laser. Conclusions: We demostratedthat true changes are evidenced at thevitreous post Lasik. Posterior vitreous detachmentis the most significant discovery and itcould be implied in the genesis of tears anddetachment of the retina, but its incidence is evensmaller than in the general population and thisallows refractive surgery to remain as a

  9. NMR Spectroscopy of the Hydrated Layer of Composite Particles Based on Nanosized Al2O3 and Vitreous Humor

    Science.gov (United States)

    Turov, V. V.; Gerashchenko, I. I.; Markina, A. I.

    2013-11-01

    The hydrated layer of composite particles prepared using Al2O3 and cattle vitreous humor was investigated using NMR spectroscopy. It was found that water bound to Al2O3 nanoparticles was present in the form of clusters with different degrees of association and energies of interaction with the surface. Water bound to the surface of the Al2O3/vitreous humor composite became more uniform upon immobilization of vitreous humor components on the surface of the Al2O3. With this, the clusters of adsorbed water had characteristics that were close to those found in air and weakly polar CHCl3 media. Addition of polar CH3CN led to the formation of very small water clusters. PMR spectra of the surface of the Al2O3/vitreous humor composite in the presence of trifluoroacetic acid differentiated four types of hydrated structures that differed in the degree of water association.

  10. [Iris hooks and modified capsular tension ring for subluxation lens in patients with Marfan's syndrome].

    Science.gov (United States)

    Wu, Wen-Jie; Zheng, Dan-ying; Zheng, Ying-feng; Cai, Xiao-yu

    2007-02-01

    To evaluate clinical efficiency and safety of the iris hooks and modified capsular tension ring (MCTR) for the treatment of subluxation lens in patients with Marfan's syndrome. This study comprised 5 patients (7 eyes) with Marfan's syndrome and subluxation lens. After 3.2 mm clear cornea incision and continuous curvilinear capsulorhexis (CCC), 2 - 4 disposable nylon iris hooks were inserted through the stab incisions and placed in the capsulorhexis to support the capsule and enlarged the CCC. Following irrigation/aspiration, a MCTR with suture in its eyelet was placed in the capsule bag. After tightening and tying the suture of MCTR, the capsular bag was centered and fixed. A foldable AcrySof one-piece intraocular lens (IOL) was then placed in the capsule bag. Twelve months after the operation, the best corrected visual acuity was >/= 0.8 in six eyes and 0.7 in one eye. The scheimpflug images obtained from the Pentacam demonstrated that the IOL were well centered. UBM showed that all the MCTR and the haptics of the IOL were in the capsule bag, the eyelet of the MCTR was rested stably between the capsulorhexis margin and the iris. The retroillumination photograph indicated that only one eye had obvious posterior capsular opacification. No intraoperative and postoperative complications such as prolapse of vitreous and retina detachment was occurred. The iris hooks can provide excellent intraoperative capsule-lens stability and facilitate the manipulation during operation. MCTR allows additional suture fixation to the eye wall without damaging the capsular bag and maintains the long-term stability of the intraocular lens. Furthermore, MCTR is helpful for avoiding dislocation of the IOL due to progressive weakening of the zonular fibers in some patients and provides long-term safety.

  11. Contact Lens Wear at Altitude: Subcontact Lens Bubble Formation

    Science.gov (United States)

    1987-11-01

    incidence of (PMMA) lenses . Reported here are the results of contact lens subcontact lens bubble formation under scleral lenses at bubble studies with soft...vision from formation of large bubbles greater than 6,096 m (20,000 It). With soft contact lenses , bubble under their contact lenses . They also found...always located at the limbus and were without sequela to vision or corneal epithelial integrity. scleral lenses used by Jaeckle were permeable to gases

  12. Flanged Intrascleral Intraocular Lens Fixation with Double-Needle Technique.

    Science.gov (United States)

    Yamane, Shin; Sato, Shimpei; Maruyama-Inoue, Maiko; Kadonosono, Kazuaki

    2017-08-01

    To report the clinical outcomes of a new technique for transconjunctival intrascleral fixation of an intraocular lens (IOL). Prospective, noncomparative, interventional case series. One hundred eyes of 97 consecutive patients with aphakia, dislocated IOL, or subluxated crystalline lens who underwent posterior chamber sutureless implantation of an IOL were studied. Two angled incisions parallel to the limbus were made by 30-gauge thin-wall needles. Haptics of an IOL were externalized with the needles and cauterized to make a flange of the haptics. The flange of the haptics were pushed back and fixed into the scleral tunnels. Best-corrected visual acuity (VA), corneal endothelial cell density, IOL tilt, and complications were determined. The IOLs were fixed with exact centration and axial stability. The mean preoperative best-corrected VA was 0.25 logarithm of the minimum angle of resolution (logMAR) units; after surgery, it improved significantly to 0.11 logMAR, 0.09 logMAR, 0.12 logMAR, and 0.04 logMAR at 6, 12, 24, and 36 months, respectively (P IOL tilt was 3.4°±2.5°. The postoperative complications included iris capture by the IOL in 8 eyes (8%), vitreous hemorrhage in 5 eyes (5%), and cystoid macular edema in 1 eye (1%). There were no incidents of postoperative retinal detachment, endophthalmitis, or IOL dislocation. We have developed a new technique for intrascleral IOL fixation. The flanged IOL fixation technique is a simple and minimally invasive method for achieving good IOL fixation with firm haptic fixation. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  13. Straylight Measurements in Contact Lens Wear

    NARCIS (Netherlands)

    van der Meulen, Ivanka J. E.; Engelbrecht, Leonore A.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Mourits, Maarten P.; Schlingemann, Reinier O.; van den Berg, Thomas J. T. P.

    2010-01-01

    Purpose: (1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints. Methods: Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens

  14. Comparative kinetics of serum and vitreous humor digoxin concentrations in a guinea pig model. Part I: Intravenous administration of digoxin

    International Nuclear Information System (INIS)

    Donnelly, B.; Balkon, J.; Bidanset, J.H.; Belmonte, A.; Barletta, M.; Manning, T.

    1991-01-01

    The pharmacokinetics of a single intravenous dose of digoxin in the guinea pig was investigated with emphasis on the penetration of digoxin into the vitreous humor. A controlled study was undertaken and data was collected which indicated that digoxin follows an open, two-compartment pharmacokinetic model with a terminal half-life of 318 minutes. The data indicated that the ratio of vitreous concentrations to serum concentrations were determined to be equal following an initial tissue distribution phase

  15. Detection of Elevated Signaling Amino Acids in Human Diabetic Vitreous by Rapid Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Miao-Jen Lu

    2007-01-01

    Full Text Available Elevated glutamate is implicated in the pathology of PDR. The ability to rapidly assess the glutamate and amino acid content of vitreous provides a more complete picture of the chemical changes occurring at the diabetic retina and may lead to a better understanding of the pathology of PDR. Vitreous humor was collected following vitrectomies of patients with PDR and control conditions of macular hole or epiretinal membrane. A capillary electrophoresis method was developed to quantify glutamate and arginine. The analysis is relatively fast (<6 minutes and utilizes a poly(ethyleneoxide and sodium dodecylsulfate run buffer. Both amino acid levels show significant increases in PDR patients versus controls and are comparable to other reports. The levels of vitreal glutamate vary inversely with the degree of observed hemorrhage. The results demonstrate a rapid method for assessment of a number of amino acids to characterize the chemical changes at the diabetic retina to better understand tissue changes and potentially identify new treatments.

  16. Migration of Intraocular Silicone Oil from the Vitreous Cavity into the Upper Eyelid Causing Ptosis

    Directory of Open Access Journals (Sweden)

    Yuzo Deguchi

    2014-07-01

    Full Text Available Introduction: To report a case in which intraocular silicone oil migrated into the upper eyelid and caused ptosis. Methods: A 65-year-old woman presented with proliferative vitreoretinopathy in the right eye. Vitrectomies, injection of silicone oil and encircling were performed. Two months after the last operation, swelling of her right eyelid occurred. Result: Magnetic resonance imaging revealed moisture in the palpebral fat tissue. We incised the bulbar conjunctiva and confirmed silicone oil leakage from the vitreous cavity through the scleral button hole of the encircling suture. Postoperatively, the right upper eyelid swelling decreased. Histopathologically, dense macrophage infiltration was seen in the palpebral tissues. Conclusions: We report a rare case with a postoperative complication caused by silicone oil. In cases with swelling of the eyelid and decreased silicon oil in the vitreous cavity postoperatively, clinicians should consider the possibility of silicone oil leakage.

  17. Imaging Drosophila brain by combining cryo-soft X-ray microscopy of thick vitreous sections and cryo-electron microscopy of ultrathin vitreous sections.

    Science.gov (United States)

    Leforestier, Amélie; Levitz, Pierre; Preat, Thomas; Guttmann, Peter; Michot, Laurent J; Tchénio, Paul

    2014-11-01

    Cryo-soft X-ray microscopy is an emerging imaging tool complementary to cryo-electron microscopy, allowing to image frozen hydrated specimens ten to hundred times thicker, but at lower resolution. We describe how the method, so far restricted to isolated small cells or cell monolayers, can be extended to large cells and tissue. We image the synapses of the Kenyon cells in frozen hydrated Drosophila brains combining cryo-soft X-ray microscopy of thick vitreous sections, and cryo-electron microscopy of ultrathin vitreous sections. We show how to obtain frozen hydrated sections of thicknesses ranging from 40 nm up to 2.5 μm, by tuning the sectioning speed of the cryo-microtome. A fluorescent stereo-microscope mounted on the cryo-microtome allowed us to target the regions of interest after GFP-labeling of synapses. Thick cryo-sections were imaged by cryo-soft X-ray microscopy at a resolution better than 25 nm, while ultrathin cryo-sections of the same regions were explored in parallel at the nanometre level of resolution by cryo-electron microscopy. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Motorized injector-assisted intrascleral intraocular lens fixation.

    Science.gov (United States)

    Hung, Jia-Horung; Wang, Shih-Hao; Teng, Yu-Ti; Hsu, Sheng-Min

    2017-03-01

    For eyes with deficient capsular support, intraocular lens (IOL) implantation has long been a technical challenge. Recently, intrascleral fixation of the haptics of a three-piece posterior chamber IOL has become a popular option. In this procedure, externalization of the leading haptic during IOL injection is a stressful step. We present a modified technique to improve the ease and safety of this step. Our modified technique involves IOL injection with a motorized injector with several important modifications described here. With these modifications, a surgeon can easily maintain the correct orientation of the IOL in a well-controlled manner during IOL injection. The records of 13 patients who underwent this technique were retrospectively evaluated. Corrected-distance visual acuity improved significantly after surgery (pIOL decentration, or vitreous hemorrhage was noted during the follow-up period. In conclusion, the motorized injector-assisted intrascleral IOL fixation technique is a safe and effective alternative to the conventional procedure. This technique makes the process of leading haptic externalization easier and more controllable. Copyright © 2017. Published by Elsevier Taiwan.

  19. Motorized injector-assisted intrascleral intraocular lens fixation

    Directory of Open Access Journals (Sweden)

    Jia-Horung Hung

    2017-03-01

    Full Text Available For eyes with deficient capsular support, intraocular lens (IOL implantation has long been a technical challenge. Recently, intrascleral fixation of the haptics of a three-piece posterior chamber IOL has become a popular option. In this procedure, externalization of the leading haptic during IOL injection is a stressful step. We present a modified technique to improve the ease and safety of this step. Our modified technique involves IOL injection with a motorized injector with several important modifications described here. With these modifications, a surgeon can easily maintain the correct orientation of the IOL in a well-controlled manner during IOL injection. The records of 13 patients who underwent this technique were retrospectively evaluated. Corrected-distance visual acuity improved significantly after surgery (p<0.05. No postoperative retinal detachment, endophthalmitis, IOL decentration, or vitreous hemorrhage was noted during the follow-up period. In conclusion, the motorized injector-assisted intrascleral IOL fixation technique is a safe and effective alternative to the conventional procedure. This technique makes the process of leading haptic externalization easier and more controllable.

  20. Structural and trapping characteristics of a new A1 defect in vitreous silica

    International Nuclear Information System (INIS)

    Brower, K.L.

    1978-01-01

    I have found with EPR that some A1 impurity atoms in type-I and -II vitreous silica are bonded to only three oxygen atoms. Under ionizing radiation at 4 K, diamagnetic AlO 3 traps an electron and becomes paramagnetic AlO 3 - ; this charge configuration is observed with EPR for T 3 - exists for T < or approx. = 550 K, but if the compensator involves hydrogen, the extra electron can remain trapped for T < or approx. = 650 K

  1. [Evaluation of the modified capsular tension ring in cases of traumatic lens subluxation].

    Science.gov (United States)

    Marques, Daniela Meira Villano; Marques, Frederico França; Cionni, Robert J; Osher, Robert Henry; Freitas, Lincoln Lemes

    2007-01-01

    To evaluate the behavior of the modified capsular tension ring (MCTR) in traumatic subluxated cataracts analyzing the visual acuity, centration of the capsular bag, pseudophacodonesis, postoperative follow-up and intra- and postoperative complications. Cincinnati Eye Institute, Cincinnati, Ohio, USA. Twenty-two eyes of 22 patients with traumatic loss of zonular support had phacoemulsification using PCIOL and MCTR implantation. The preoperative examination included best correct visual acuity (BCVA) and the presence or absence of phacodonesis, lens decentration and vitreous prolapse. The postoperative evaluation included BCVA, the presence of pseudophacodonesis, PCIOL centration, necessity of vitrectomy and other complications. 21 eyes (95.45%) had an improvement in BCVA. The preoperative examination disclosed phacodonesis in 11 eyes (50%) and no eye presented pseudophacodonesis in the postoperative period. Preoperatively, symptomatic decentration was presented by 10 eyes (45.45%) and 22 eyes (100%) had no decentration after surgery. The preoperative examination revealed vitreous prolapse in the anterior chamber in 9 eyes (40.90%). Vitrectomy was required in 11 eyes (50%). The use of the MCTR resulted in a good centration of the capsular bag and the PC IOL in 22 eyes with traumatic cataract and loss of zonular support.

  2. Scleral depressed vitreous shaving, 360 laser, and perfluoropropane (C3 F8) for retinal detachment

    Science.gov (United States)

    Chaturvedi, Vivek; Basham, Ryan P; Rezaei, Kourous A

    2014-01-01

    Purpose: To review the characteristics and outcomes of patients who underwent pars plana vitrectomy (PPV) with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% C3F8 gas for rhegmatogenous retinal detachment (RRD). Materials and Methods: A retrospective review of a consecutive series of patients who underwent primary repair of RRD by PPV with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% perfluoropropane (C3F8) was conducted. Patients with less than 3 months follow-up, previous retinal surgery, and higher than grade B proliferative vitreoretinopathy were excluded. Results: Ninety-one eyes were included in the study. The mean age was 60.1 years. The mean follow-up was 13.7 months. The macula was detached in 63% (58/91) of the eyes. The reattachment rate after one surgical procedure was 95% (86/91) while overall reattachment rate was 100%. There was no statistically significant difference between reattachment rates of superior, nasal/temporal, or inferior RRDs. The mean final best corrected visual acuity (BCVA) was 20/40. Of all the patients, 66% of patients with macula-off RRDs had a final BCVA of 20/40 or better. Conclusions: PPV with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% C3F8 leads to successful anatomical reattachment with visual improvement in patients with primary RRD. PMID:25116775

  3. Prevalence and Associations of Incomplete Posterior Vitreous Detachment in Adult Chinese: The Beijing Eye Study

    Science.gov (United States)

    Shao, Lei; Xu, Liang; You, Qi Sheng; Wang, Ya Xing; Chen, Chang Xi; Yang, Hua; Zhou, Jin Qiong; Jonas, Jost B.; Wei, Wen Bin

    2013-01-01

    Purpose To determine prevalence and associations of incomplete posterior vitreous detachment (PVD). Methods The population-based cross-sectional Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range: 50–93 years). A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD-OCT). Incomplete PVD was differentiated into type 1 (shallow PVD with circular perifoveal vitreous attachment), type 2 (PVD reaching fovea but not foveola), type 3 (shallow PVD with pinpoint vitreous attachment at the foveola), and type 4 (PVD completely detached from the macula, attached to the optic disc). Results An incomplete PVD was detected in 3948 eyes (prevalence: 60.5±0.6%; 95% Confidence Interval (CI): 59.3%,61.7%) of 2198 subjects (67.1±0.8%;95%CI: 65.6%,68.7%). Type 1 PVD was seen in 3090 (78.3%) eyes, type 2 PVD in 504 (12.8%) eyes, type 3 PVD in 70 (1.8%) eyes, and type 4 PVD in 284 (7.2%) eyes. Prevalence of incomplete PVD was associated with younger age (PPVD was associated with higher age (PPVD (detected in 67.1% subjects) was associated with younger age, male gender, rural region of habitation, larger corneal diameter, better best corrected visual acuity and hyperopic refractive error. PMID:23544043

  4. Scleral depressed vitreous shaving, 360 laser, and perfluoropropane (C 3 F 8 for retinal detachment

    Directory of Open Access Journals (Sweden)

    Vivek Chaturvedi

    2014-01-01

    Full Text Available Purpose : To review the characteristics and outcomes of patients who underwent pars plana vitrectomy (PPV with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% C3F8 gas for rhegmatogenous retinal detachment (RRD. Materials and Methods : A retrospective review of a consecutive series of patients who underwent primary repair of RRD by PPV with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% perfluoropropane (C 3 F 8 was conducted. Patients with less than 3 months follow-up, previous retinal surgery, and higher than grade B proliferative vitreoretinopathy were excluded. Results : Ninety-one eyes were included in the study. The mean age was 60.1 years. The mean follow-up was 13.7 months. The macula was detached in 63% (58/91 of the eyes. The reattachment rate after one surgical procedure was 95% (86/91 while overall reattachment rate was 100%. There was no statistically significant difference between reattachment rates of superior, nasal/temporal, or inferior RRDs. The mean final best corrected visual acuity (BCVA was 20/40. Of all the patients, 66% of patients with macula-off RRDs had a final BCVA of 20/40 or better. Conclusions: PPV with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% C 3 F 8 leads to successful anatomical reattachment with visual improvement in patients with primary RRD.

  5. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; Agarwal, P

    2010-01-01

    A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are: overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. Th...

  6. A course in lens design

    CERN Document Server

    Velzel, Chris

    2014-01-01

    A Course in Lens Design is an instruction in the design of image-forming optical systems. It teaches how a satisfactory design can be obtained in a straightforward way. Theory is limited to a minimum, and used to support the practical design work. The book introduces geometrical optics, optical instruments and aberrations. It gives a description of the process of lens design and of the strategies used in this process. Half of its content is devoted to the design of sixteen types of lenses, described in detail from beginning to end. This book is different from most other books on lens design because it stresses the importance of the initial phases of the design process: (paraxial) lay-out and (thin-lens) pre-design. The argument for this change of accent is that in these phases much information can be obtained about the properties of the lens to be designed. This information can be used in later phases of the design. This makes A Course in Lens Design a useful self-study book, and a suitable basis for an intro...

  7. Gabor lens theory

    International Nuclear Information System (INIS)

    Irani, A.A.

    1978-01-01

    The principle of using the space charge of an electron cloud to focus ion beams was first proposed by Gabor. Electrons are to be confined radially by means of an axial magnetic field B/sub z/ and axially by means of externally applied electric fields E/sub z/. An ion beam of charge density n/sub i/ much less than n/sub e/, the electron charge density can then be focused by the radial electric field set up by the electron cloud. The case considered here is that of a hollow cylindrical conductor charged to a potential +V with grounded rings on either side to set up the axial E/sub z/ field. A solenoid wound around the central conductor supplies the B/sub z/ field. Theoretical calculations are carried out for n/sub e/ maximum as a function of B/sub z/ due to radial confinement and V due to axial confinement and the focal length of the Gabor Lens is calculated

  8. No turnover in lens lipids for the entire human lifespan.

    Science.gov (United States)

    Hughes, Jessica R; Levchenko, Vladimir A; Blanksby, Stephen J; Mitchell, Todd W; Williams, Alan; Truscott, Roger J W

    2015-03-11

    Lipids are critical to cellular function and it is generally accepted that lipid turnover is rapid and dysregulation in turnover results in disease (Dawidowicz 1987; Phillips et al., 2009; Liu et al., 2013). In this study, we present an intriguing counter-example by demonstrating that in the center of the human ocular lens, there is no lipid turnover in fiber cells during the entire human lifespan. This discovery, combined with prior demonstration of pronounced changes in the lens lipid composition over a lifetime (Hughes et al., 2012), suggests that some lipid classes break down in the body over several decades, whereas others are stable. Such substantial changes in lens cell membranes may play a role in the genesis of age-related eye disorders. Whether long-lived lipids are present in other tissues is not yet known, but this may prove to be important in understanding the development of age-related diseases.

  9. Association between aqueous humor and vitreous fluid levels of Th17 cell-related cytokines in patients with proliferative diabetic retinopathy.

    Science.gov (United States)

    Takeuchi, Masaru; Sato, Tomohito; Sakurai, Yutaka; Taguchi, Manzo; Harimoto, Kozo; Karasawa, Yoko; Ito, Masataka

    2017-01-01

    Inflammation is known to be involved in the progression of diabetic retinopathy. We have recently reported that vitreous levels of IL-4, IL-17A, IL-22, IL-31, and TNFα are higher than the respective serum levels in proliferative diabetic retinopathy (PDR) patients, and that vitreous levels of these cytokines are higher in PDR than in other non-inflammatory vitreoretinal diseases or uveitis associated with sarcoidosis. In the present study, we investigated inflammatory cytokines including Th17 cell-related cytokines in aqueous humor samples obtained from eyes with PDR, and analyzed the association between the aqueous humor and vitreous fluid levels of individual cytokines. The study group consisted of 31 consecutive type 2 diabetic patients with PDR who underwent cataract surgery and vitrectomy for vitreous hemorrhage and/or tractional retinal detachment. Undiluted aqueous humor was collected during cataract surgery, and then vitreous fluid was obtained using a 25G vitreous cutter inserted into the mid-vitreous cavity at the beginning of vitrectomy. IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, soluble CD40 ligand (sCD40L), and TNFα levels in the aqueous humor and vitreous fluid were measured using a beads-array system. Although IL-17A was detected in the aqueous humor of eyes with PDR and the level correlated with IL-17A level in the vitreous fluid, both percent detectable and level of IL-17A in the aqueous humor were significantly lower than those in the vitreous fluid. Vitreous IL-17A level was related significantly to IL-10, IL-22, and TNFα levels in aqueous humor as well as in vitreous fluid, On the other hand, aqueous IL-17A level was not related significantly to aqueous or vitreous levels of IL-10, IL-22 or TNFα level. The present study demonstrated that IL-17A level and detectable rate in the aqueous humor of patients with PDR are markedly lower than those in the vitreous fluid and aqueous IL-17A does not

  10. [Contact lens care and maintenance].

    Science.gov (United States)

    Bloise, L

    2017-04-01

    All contact lenses with replacement schedules longer than daily must be maintained. At each step of their use, the lenses may be contaminated. Contact lens solutions perform the essential functions of cleaning, decontaminating and preserving the lenses to prevent infectious problems and improve wearing comfort. Contact lens contamination essentially comes from hands, cleaning solutions, cases, water and the environment. The pathogenic microorganisms are mainly Gram-negative bacteria, fungi and amoebae. Contact lens deposits may or may not have an organic origin. Their presence increases the risk of infection because they serve as a nutrient matrix for microbes, and they are responsible for wearing discomfort. Contact lens solutions differ in their composition, their mechanism of action and the concentration of the various agents. To prescribe the best lens care system to each wearer and for each material, it is necessary to be very familiar with them. Maintenance is the main cause of discomfort with contact lenses, either through improper use, solution-material incompatibility, or a reaction of the wearer to the components. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  12. Automated Fresnel lens tester system

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.S.

    1981-07-01

    An automated data collection system controlled by a desktop computer has been developed for testing Fresnel concentrators (lenses) intended for solar energy applications. The system maps the two-dimensional irradiance pattern (image) formed in a plane parallel to the lens, whereas the lens and detector assembly track the sun. A point detector silicon diode (0.5-mm-dia active area) measures the irradiance at each point of an operator-defined rectilinear grid of data positions. Comparison with a second detector measuring solar insolation levels results in solar concentration ratios over the image plane. Summation of image plane energies allows calculation of lens efficiencies for various solar cell sizes. Various graphical plots of concentration ratio data help to visualize energy distribution patterns.

  13. Compliance among soft contact lens wearers.

    Science.gov (United States)

    Kuzman, Tomislav; Kutija, Marija Barisić; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurisić, Darija; Skegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-12-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in different aspects of lens care handling and wearing habits. In our research 50 asymptomatic lens wearers filled out a questionnaire containing demographic data, lens type, hygiene and wearing habits, lenses and lens care system replacement schedule and self-evaluation of contact lens handling hygiene. We established criteria of compliance according to available manufacturer's recommendations, prior literature and our clinical experience. Only 2 (4%) of patients were fully compliant SCL wearers. The most common non-compliant behaviours were insufficient lens solution soaking time (62%), followed by failure to daily exchange lens case solution and showering while wearing lenses. 44% of patients reported storing lenses in saline solution. Mean lens storage case replacement was 3.6 months, with up to 78% patients replacing lens case at least once in 3 months. Average grade in self evaluating level of compliance was very good (4 +/- 0.78) (from 1-poor level of hygiene to 5-great level of hygiene). Lens wearers who reported excessive daily lens wear and more than 10 years of lens wearing experience were also found to be less compliant with other lens system care procedures. (t = -2.99, df=47, p lens system maintenance steps. Most common non-compliant behaviours were the ones that are crucial for maintaining lens sterility and preventing infection. Despite the low objective compliance rate, self grading was relatively high. Therefore, these results indicate the need for patient

  14. Dose limits to the eye lens

    Energy Technology Data Exchange (ETDEWEB)

    Sion, N.

    2016-09-15

    Protecting the human body from the effects of ionizing radiation is essential to forestall stochastic effects and require placing limits on the effective dose. Dose limits on specific organs are also necessary to reduce the deterministic effects and tissue reactions. The standard for radiation protection was ISO 15382 (2002) which mainly dealt with beta radiation for nuclear power plant workers. Clearly an update is required to allow for new technology and the proliferative use of radiation in medical practices. There is a need for more explicit radiation monitoring to operators and staff. ICRP118 (International Commission on Radiological Protection), Ref. 1, evolved their recommendations to include eye lens doses as a follow on to their publication 103 and to focus on radiation exposures. It provides updated estimates of 'practical' threshold doses for tissue injury at the level of 1% incidence. This paper discusses the current status and the recommendation for a drastic reduction of the dose limit to the eye lens. (author)

  15. Curiosity's Mars Hand Lens Imager (MAHLI) Investigation

    Science.gov (United States)

    Edgett, Kenneth S.; Yingst, R. Aileen; Ravine, Michael A.; Caplinger, Michael A.; Maki, Justin N.; Ghaemi, F. Tony; Schaffner, Jacob A.; Bell, James F.; Edwards, Laurence J.; Herkenhoff, Kenneth E.; Heydari, Ezat; Kah, Linda C.; Lemmon, Mark T.; Minitti, Michelle E.; Olson, Timothy S.; Parker, Timothy J.; Rowland, Scott K.; Schieber, Juergen; Sullivan, Robert J.; Sumner, Dawn Y.; Thomas, Peter C.; Jensen, Elsa H.; Simmonds, John J.; Sengstacken, Aaron J.; Wilson, Reg G.; Goetz, Walter

    2012-01-01

    The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ?5 km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ?2.1 cm to infinity. At the minimum working distance, image pixel scale is ?14 μm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI?s resolution is comparable at ?30 μm per pixel. Onboard capabilities include autofocus, auto-exposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage.

  16. Mass diffusion coefficient measurement for vitreous humor using FEM and MRI

    Science.gov (United States)

    Rattanakijsuntorn, Komsan; Penkova, Anita; Sadha, Satwindar S.

    2018-01-01

    In early studies, the ‘contour method’ for determining the diffusion coefficient of the vitreous humor was developed. This technique relied on careful injection of an MRI contrast agent (surrogate drug) into the vitreous humor of fresh bovine eyes, and tracking the contours of the contrast agent in time. In addition, an analytical solution was developed for the theoretical contours built on point source model for the injected surrogate drug. The match between theoretical and experimental contours as a least square fit, while floating the diffusion coefficient, led to the value of the diffusion coefficient. This method had its limitation that the initial injection of the surrogate had to be spherical or ellipsoidal because of the analytical result based on the point-source model. With a new finite element model for the analysis in this study, the technique is much less restrictive and handles irregular shapes of the initial bolus. The fresh bovine eyes were used for drug diffusion study in the vitreous and three contrast agents of different molecular masses: gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA, 938 Da), non-ionic gadoteridol (Prohance, 559 Da), and bovine albumin conjugated with gadolinium (Galbumin, 74 kDa) were used as drug surrogates to visualize the diffusion process by MRI. The 3D finite element model was developed to determine the diffusion coefficients of these surrogates with the images from MRI. This method can be used for other types of bioporous media provided the concentration profile can be visualized (by methods such as MRI or fluorescence).

  17. Early Vitreous Surgery in the Treatment of Aggressive Posterior Retinopathy of Prematurity

    Directory of Open Access Journals (Sweden)

    A. V. Tereshhenko

    2017-01-01

    Full Text Available The goal is to identify objective indications for early primary vitreous surgery in infants with aggressive posterior ROP and to develop a methodology. Patients and methods. The study included 20 preterm infants (40 eyes with aggressive posterior ROP at the stage of formation exudative-tractional retinal detachment, which were divided into two groups. The main group consisted of 10 infants (20 eyes with severe manifestations of aggressive posterior ROP. The control group included 10 premature infants (20 eyes with aggressive posterior ROP, who underwent transpupillary laser coagulation of the retina (LC. In all cases (20 eyes 5-8 days after LC was recorded the progression of the disease. Based on data from a complex ophthalmic examination, given the progression of the disease after LC in the control group and baseline severe aggressive posterior ROP in the main group with the control with identical clinical picture, patients in both groups was made early vitreous surgery: in the main group — after ophthalmological examination and control after 8-16 days after LC. Results. In the main group after 6 months in 15 eyes (75% formed the correct vitreomacular interface, in 5 cases (25% were diagnosed with the smoothness of the foveolar pits by sealing the internal limiting membrane with no signs of retinal edema. In the control group after 6 months in 6 eyes (30% formed the right macular interface in 11 (55% — was defined by flatness or lack foveolar pit with no signs of retinal edema. On 3 eyes (15% in the 2nd zone remained a local retinal detachment. Conclusion. Primary vitrectomy performed according to the developed indications, allows to optimize the treatment of patients with aggressive posterior ROP in cases of inefficiency of the LC. It is an alternative and pathogenetically substantiated technology, which efficiency is not inferior to the traditional approach, including LС followed by vitreous surgery.

  18. Computer-aided lens assembly

    Science.gov (United States)

    Tomlinson, Richard; Alcock, Rob; Petzing, Jon; Coupland, Jeremy

    2004-01-01

    We propose a computer-aided method of lens manufacture that allows assembly, adjustment, and test phases to be run concurrently until an acceptable level of optical performance is reached. Misalignment of elements within a compound lens is determined by a comparison of the results of physical ray tracing by use of an array of Gaussian laser beams with numerically obtained geometric ray traces. An estimate of misalignment errors is made, and individual elements are adjusted in an iterative manner until performance criteria are achieved. The method is illustrated for the alignment of an air-spaced doublet.

  19. Acanthamoeba keratitis. Contact lens and noncontact lens characteristics.

    Science.gov (United States)

    Chynn, E W; Lopez, M A; Pavan-Langston, D; Talamo, J H

    1995-09-01

    To identify potential differences in time to diagnosis and final visual outcome between contact lens and noncontact lens users with Acanthamoeba keratitis. Prior studies have shown early diagnosis and therapy to be related to outcome but have not analyzed differences among patients with and without contact lenses. A retrospective analysis of 11 consecutive cases (involving 13 eyes) of Acanthamoeba keratitis diagnosed at one institution over a 3-year period. Mean time to diagnosis was significantly longer in noncontact lens users versus those who wore contact lenses (mean, 5.8 versus 3.3 weeks). Fifty percent of patients who did not wear contact lenses had a poor outcome (visual acuity worse than 20/40 or penetrating keratoplasty) versus 14% of patients who wore contact lenses. Diagnoses were made later in patients without contact lenses, and these patients had a worse visual outcome than those with Acanthamoeba keratitis who wore contact lenses. All patients with unresponsive microbial keratitis, even those without contact lens use, should be evaluated for Acanthamoeba.

  20. Posterior vitreous detachment with microplasmin alters the retinal penetration of intravitreal bevacizumab (Avastin) in rabbit eyes.

    Science.gov (United States)

    Goldenberg, David T; Giblin, Frank J; Cheng, Mei; Chintala, Shravan K; Trese, Michael T; Drenser, Kimberly A; Ruby, Alan J

    2011-02-01

    Intravitreal bevacizumab (BV) (Avastin, Genentech Inc., South San Francisco, CA) is frequently used for the treatment of age-related macular degeneration. Previous studies have demonstrated full-thickness retinal penetration. Intravitreal recombinant microplasmin (MP) has been shown to successfully induce a posterior vitreous detachment (PVD) and vitreous liquefaction in animals. It has been suggested that a PVD may alter the retinal penetration of molecules in the vitreous cavity. The aim of this study was to compare BV retinal penetration in rabbit eyes with and without an MP-induced PVD. Twelve adult rabbits were injected with 0.1 mL (0.4 mg) of MP into the vitreous cavity of 1 eye. One week later, the rabbits were injected with 0.05 mL (1.25 mg) of BV into both eyes. Both eyes of 3 rabbits were harvested at 6 hours, 12 hours, 24 hours, and 72 hours after the BV injection. Frozen retinal cross sections were prepared, and BV retinal penetration was evaluated with immunohistochemistry using a fluorescence-labeled antibody against BV. Two eyes from one rabbit were not injected with either agent and used as controls to compare the background autofluorescence. Peripapillary retinal sections were recorded with a digital camera, and intraretinal BV fluorescence-labeled antibody was measured by qualitative photographic interpretation. Two additional rabbits received an intravitreal injection of 0.1 mL of MP in 1 eye. One week later, both eyes from each rabbit were enucleated, and frozen retinal sections were prepared and analyzed with light microscopy to evaluate histologic damage. Full-thickness BV retinal penetration was observed throughout the retina in both eyes of each rabbit. All the MP-injected eyes exhibited increased antibody labeling in retinas evaluated at 6 hours, 12 hours, and 24 hours after BV injection when compared with the contralateral non-MP-injected eyes. By 3 days after BV injection, all eyes demonstrated decreased antibody labeling compared with

  1. Posterior Vitreous Detachment as Observed by Wide-Angle OCT Imaging.

    Science.gov (United States)

    Tsukahara, Mayuka; Mori, Keiko; Gehlbach, Peter L; Mori, Keisuke

    2018-04-06

    Posterior vitreous detachment (PVD) plays an important role in vitreoretinal interface disorders. Historically, observations of PVD using OCT have been limited to the macular region. The purpose of this study is to image the wide-angle vitreoretinal interface after PVD in normal subjects using montaged OCT images. An observational cross-sectional study. A total of 144 healthy eyes of 98 normal subjects aged 21 to 95 years (51.4±22.0 [mean ± standard deviation]). Montaged images of horizontal and vertical OCT scans through the fovea were obtained in each subject. Montaged OCT images. By using wide-angle OCT, we imaged the vitreoretinal interface from the macula to the periphery. PVD was classified into 5 stages: stage 0, no PVD (2 eyes, both aged 21 years); stage 1, peripheral PVD limited to paramacular to peripheral zones (88 eyes, mean age 38.9±16.2 years, mean ± standard deviation); stage 2, perifoveal PVD extending to the periphery (12 eyes, mean age 67.9±8.4 years); stage 3, peripapillary PVD with persistent vitreopapillary adhesion alone (7 eyes, mean age 70.9±11.9 years); stage 4, complete PVD (35 eyes, mean age 75.1±10.1 years). All stage 1 PVDs (100%) were observed in the paramacular to peripheral region where the vitreous gel adheres directly to the cortical vitreous and retinal surface. After progression to stage 2 PVD, the area of PVD extends posteriorly to the perifovea and anteriorly to the periphery. Vitreoschisis was observed in 41.2% at PVD initiation (stage 1a). Whereas prior work suggests that PVD originates in the perifoveal region and after the sixth decade, our observations demonstrate that (1) PVD first appears even in the third decade of life and gradually appears more extensively throughout life; (2) more than 40% of eyes without fundus diseases at their PVD initiation are associated with vitreoschisis; and (3) PVD is first noted primarily in the paramacular-peripheral region where vitreous gel adheres to the retinal surface and is

  2. Removal of Cd+2 from aqueous solutions onto polypyrrole coated reticulated vitreous carbon eletrodes

    OpenAIRE

    Tramontina Jucelânia; Machado Giovanna; Azambuja Denise S.; Piatnicki Clarisse M.S.; Samios Dimitrios

    2001-01-01

    The development of simple methods for removal of heavy metals from aqueous samples is a relevant field of research. In this connection, the electrodeposition of the Cd+2 ion, one of the most toxic species for animals and human beings, was investigated in aerated pH 4.8 sulfuric-sulfate solutions. In potentiostatic conditions, the maximum rate of cadmium deposition at a neutral polypyrrole (PPy0) coated reticulated vitreous carbon (RVC) working electrode occurs at -3.0 V vs. the saturated calo...

  3. Effects of dietary deficiency of selective amino acids on the function of the cornea and lens in rats.

    Science.gov (United States)

    Wegener, A; Golubnitschaja, O; Breipohl, W; Schild, H H; Vrensen, G F J M

    2002-01-01

    Effects of dietary deficiencies of tryptophan and methionin on the transparency of cornea and lens were investigated in young rats (Brown-Norway, BN; Sprague-Dawley, SD) over 3 months. Transparency of the cornea and lens were evaluated in weekly intervals using a photo-slitlamp microscope. After sacrifice and lens fresh weight determination the lenses were prepared for histopathology. Methionin deficiency had no effect on the parameters investigated. Tryptophan deficiency caused severe loss of body weight in both strains, with additional loss of hair in SD rats. These developed corneal neovascularisations and cataracts. BN rats showed an enhanced zone of discontinuity in the lens. Diet intermission arrested the pathological processes in the eye which restarted when feeding the diet again. This observation is supported by lens fresh weight data. DNA staining evidenced that tryptophan deficiency arrested lens fiber maturation in both strains but stimulated corneal neovascularisation only in SD rats.

  4. A microcapillary lens for X-rays

    CERN Document Server

    Dudchik, Y I

    1999-01-01

    A new design of a compound refractive lens for X-rays is proposed. The lens is made as a set of glue microlenses placed in a glass capillary. The technique of lens fabrication is described. Results of ray tracing calculations for 8 and 15 keV photons are represented.

  5. Vitreous and plasma VEGF levels as predictive factors in the progression of proliferative diabetic retinopathy after vitrectomy.

    Science.gov (United States)

    Wang, Jiaxing; Chen, Song; Jiang, Feng; You, Caiyun; Mao, Chunjie; Yu, Jinguo; Han, Jindong; Zhang, Zhuhong; Yan, Hua

    2014-01-01

    To investigate the vitreous and plasma levels of vascular endothelial growth factor (VEGF) in patients with proliferative diabetic retinopathy (PDR) and to determine whether they predict a disease prognosis after primary vitrectomy. Fifty patients (50 eyes) with PDR who underwent pars plana vitrectomy (PPV) and 56 healthy controls (56 eyes) were enrolled in this retrospective study. Clinical data were collected and analyzed. Vitreous and plasma VEGF concentrations were measured using enzyme-linked immunosorbent assays. VEGF levels and clinical data were compared and analyzed to see if they provide a prognosis of PDR progression after primary vitrectomy at more than 6 months follow-up. Correlation of VEGF concentrations between vitreous fluid and plasma was analyzed. The average BCVA was significantly improved after surgery (Ppredictive factor for the outcome of vitrectomy in patients with PDR.

  6. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  7. Spinning pipe gas lens revisited

    CSIR Research Space (South Africa)

    Mafusire, C

    2008-01-01

    Full Text Available , there is little information on optical phase aberrations and no study to date on the propagation parameters of the laser beam, but has rather remained rooted in the domain of ray optics. Researchers revisit the spinning pipe gas lens in this paper with new...

  8. A model for the linear stability of the interface between aqueous humor and vitreous substitutes after vitreoretinal surgery

    Science.gov (United States)

    Isakova, Krystyna; Pralits, Jan O.; Repetto, Rodolfo; Romano, Mario R.

    2014-12-01

    We consider the motion of two immiscible viscous fluids induced by periodic oscillations of a flat solid surface along its plane. The interface between the two fluids is parallel to the solid wall; one fluid occupies the region between the wall and the interface and the other extends from the interface to infinity. We study numerically the linear stability of the interface with respect to two-dimensional perturbations using the normal mode analysis and assuming quasi-steady flow conditions. The analysis is motivated by the need of understanding the behavior of vitreous substitutes inserted in the vitreous chamber of the eye after vitrectomy. This is a common surgical procedure adopted to treat retinal detachments, whereby the vitreous humor is removed from the eye and replaced by fluids immiscible with water. Owing to their hydrophobic nature, vitreous substitutes coexist in the vitreous chamber with a certain amount of aqueous humor (the fluid produced in the anterior part of the eye) and, typically, a thin layer of aqueous separates the tamponade fluid from the retina. A common problem with this treatment is that, in some cases, the interface between the two fluids breaks down and this might eventually lead to the generation of an emulsion. It is believed that mechanics plays an important role in this process but the problem remains very poorly understood. We find that instability of the interface is possible in a range of parameters that is relevant for the problem that motivated the present analysis. This suggests that shear instability is likely a possible mechanism triggering the onset of vitreous substitutes-aqueous interface instability.

  9. Tube entrance lens focus control

    Science.gov (United States)

    Weisser, D. C.; Fifield, L. K.; Kitchen, T. F. G.; Tunningley, T. B.; Lobanov, N. R.; Muirhead, A. G.

    2013-02-01

    The entrance of the accelerator tube in a large electrostatic accelerator imposes a strong lens that dominates the beam optics. The magnification of the lens is large because of the low injection energy, the high voltage gradient of the acceleration tube and the long distance to the terminal. In the absence of the acceleration, the magnification would produce an unacceptably large beam spot at the terminal. The tyranny of the lens is especially irksome when the accelerator is required to operate at a lower terminal voltage than the one corresponding to the nominal gradient at high voltage. One way around the difficulty, used in NEC Pelletron accelerators, is to insert a series of nylon and steel rods that short together units of the acceleration structure at the terminal leaving the ones near the entrance close to the nominal gradient for optimum transmission. This operation takes time and risks the loss of insulating gas. Another alternative used in the 25URC at Oak Ridge National Laboratory, is to focus the beam at the tube entrance, substantially diluting the effect of the entrance lens. The beam then diverges and so requires an additional lens part way to the terminal. This solution is only partially effective and still necessitates use of shorting rods for low voltage operation. The fact that these elaborate strategies are used is evidence that the alternative of lowering the injection energy as the terminal voltage is lowered imposes enough problems that it is not used in practice. We have modeled a solution that controls the voltage gradient at the tube entrance using an external power supply. This not only maintains the focusing effect of the lens but provides the opportunity to tune the beam by adjusting the entrance lens. A 150 kV power supply outside the pressure vessel feeds a controllable voltage through a high voltage feed-through to the fifth electrode of the accelerator tube. Thus 150 kV on this electrode creates the nominal gradient of 30 kV per

  10. Relationships between vitreous levels of soluble receptor for advanced glycation end products (sRAGE) and renal function in patients with diabetic retinopathy.

    Science.gov (United States)

    Katagiri, Makiko; Shoji, Jun; Kato, Satoshi; Kitano, Shigehiko; Uchigata, Yasuko

    2017-12-01

    We investigated the relationship between vitreous levels of soluble receptor for advanced glycation end products (sRAGE) and vascular endothelial growth factor (VEGF) and renal function, and correlations between vitreous sRAGE levels and proliferative diabetic retinopathy (PDR) activity. We examined 33 eyes from 33 patients with diabetes mellitus who underwent a vitrectomy (eight patients in the non-PDR [NPDR] group and 25 in the PDR group). Serum creatinine levels and estimated glomerular filtration rate (eGFR) were measured and classified according to the chronic kidney disease (CKD)-staging method. Enzyme-linked immunosorbent assay (ELISA) was performed to quantify vitreous sRAGE and VEGF levels. Vitreous sRAGE levels were significantly higher in PDR group compared to NPDR group (p = 0.00003). Vitreous sRAGE levels were significantly higher in patients with CKD stage 5 (end-stage renal failure or hemodialysis) than in patients with CKD stage 1 or 2 (p renal function, and low vitreous sRAGE levels in patients with PDR were associated with postoperative vitreous hemorrhage. Vitreous sRAGE may be a useful biomarker for renal dysfunction associated with diabetic retinopathy.

  11. Investigation of the motion of a viscous fluid in the vitreous cavity induced by eye rotations and implications for drug delivery

    International Nuclear Information System (INIS)

    Bonfiglio, Andrea; Repetto, Rodolfo; Stocchino, Alessandro; Siggers, Jennifer H

    2013-01-01

    Intravitreal drug delivery is a commonly used treatment for several retinal diseases. The objective of this research is to characterize and quantify the role of the vitreous humor motion, induced by saccadic movements, on drug transport processes in the vitreous chamber. A Perspex model of the human vitreous chamber was created, and filled with a purely viscous fluid, representing eyes with a liquefied vitreous humor or those containing viscous tamponade fluids. Periodic movements were applied to the model and the resulting three-dimensional (3D) flow fields were measured. Drug delivery within the vitreous chamber was investigated by calculating particle trajectories using integration over time of the experimental velocity fields. The motion of the vitreous humor generated by saccadic eye movements is intrinsically 3D. Advective mass transport largely overcomes molecular diffusive transport and is significantly anisotropic, leading to a much faster drug dispersion than in the case of stationary vitreous humor. Disregarding the effects of vitreous humor motion due to eye movements when predicting the efficiency of drug delivery treatments leads to significant underestimation of the drug transport coefficients, and this, in turn, will lead to significantly erroneous predictions of the concentration levels on the retina. (paper)

  12. Progressive Outer Retinal Necrosis Combined with Vitreous Hemorrhage in a Patient with Acquired Immunodeficiency Syndrome

    Science.gov (United States)

    You, Yong Sung; Lee, Sung Jin; Lee, Sung Ho; Park, Chang Hyun

    2007-01-01

    Purpose To describe an unusual case of rapidly progressive outer retinal necrosis (PORN) with vitreous hemorrhage in a 41-year-old woman with acquired immunodeficiency syndrome (AIDS), who had retinitis developed from what was probably varicellar-zoster virus combined with cytomegalovirus (CMV) and herpes simplex type 1,2, as proven by the polymerase chain reaction restriction fragment length polymorphism method (PCR-RFLP). Methods This study is a case report detailing clinical follow-up and an aqueous humor test by PCR-RFLP. Results The deep, white retinal lesions coalesced and progressively expanded in a circumferential manner, with sparing of the perivascular retina. However, retinal and vitreous hemorrhages, unusual findings for PORN, could be noted around the optic nerve. Varicellar-zoster virus (VZV), cytomegalovirus (CMV), and herpes simplex types 1,2 (HSV-1,2) were detected in the aqueous humor by PCR. Conclusions PORN has been described as a variant of necrotizing herpetic retinopathy, occurring particularly in patients with AIDS. Although the etiologic agent has been reported to be VZV, concurrent or combined etiologic agents can include HSV-1, HSV-2, and CMV in AIDS patients. Therefore, combined antiviral therapy with acyclovir and ganciclovir could be more reasonable as an initial therapy. PMID:17460434

  13. Recovery of platinum from concentrated sodium chloride brine by electrodeposition on vitreous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Harrar, J.E.; Stephens, F.B.

    1984-01-01

    The voltammetric characteristics of Pt(II) and Pt(IV) have been examined at a vitreous carbon electrode in slightly acidic 3M (approx. 15 wt %) NaCl solutions. Pt(IV) is reduced to Pt(II) at approx. 0 V and Pt(II) is reduced to Pt(0) at approx. -0.5 V vs Ag-AgCl. The rate of deposition of platinum metal at -0.5 V is very low on bare carbon, but increases as the coverage of platinum increases. The potential at which hydrogen is evolved in this medium is approx. -0.85 V. A technique has been tested for the removal of sub-part-per-million levels of platinum from the high-salinity brine by controlled-potential electrolysis using a reticulated, vitreous-carbon, flow-through electrode. However, at control potentials negative enough to begin to electrodeposit the platinum at a significant rate, simultaneous reduction of hydrogen ion reduces the current and energy efficiency to an unacceptable level.

  14. USE OF VITREOUS FERTILIZERS WITH SLOW RELEASE OF NUTRIENTS IN VITICULTURE

    Directory of Open Access Journals (Sweden)

    M. Ion

    2012-04-01

    Full Text Available An experiment was conducted to study the possibility of using vitreous fertilizers made from waste from the glass industry in vineyards fertilization. Six recipes were tested having as composition the basic elements: P2O5 (43.5%, K2O (32.6%, MgO (18.5% and CaO (5.4%, plus the presence of some micronutrients (B, Fe, Zn, Mo, Mn as oxide form. The efficiency of these fertilizers was made in comparison both with an unfertilized plot and an fertilized plot with NPK applied on the base of optimal rates. The experimental results have shown that this type of fertilizers can replace the use of common chemical fertilizers, their effect on the fertility and productivity of grapevine being relative similar, the benefit consisting of slow release over a long period of time of the nutrients from their composition with positive effects in preventing environmental pollution. The presence of micronutrients in their composition determined even higher yields (by 10-19% as compare to chemical fertilization and a higher content (by 8-45 % of anthocyanins in grapes when vitreous fertilizers had B, Fe, Zn and Mo in their composition.

  15. Ceramics Vitreous China Produced by Utilizing Sediment Soil from Water Supply Treatment Process

    Directory of Open Access Journals (Sweden)

    Wangrakdiskul Ubolrat

    2017-01-01

    Full Text Available Due to generating the abundant of sediment soil, it makes the high burden of disposal cost to the metropolitan waterworks authority. Enhancing the value of sediment soil has been explored. This research aims to utilize the sediment soil, wastes of water supply treatment process for producing ceramics vitreous china. In this experiment, five types of raw materials are exploited, namely, sediment soil, ball clay, kaolin, feldspar and silica sand. The formulas have been divided into two groups. Sediment soil has been used as substituted material in ball clay for the first group, and substituted in kaolin for the second group. The specimens of each formula are formed by uniaxial pressing at 100 bar of size 50×100×7 mm. Then they have been sintered at two different temperatures, 1200°C and 1250°C, with heating rate 400° C/ hr and soaking for 30 minutes. The result reveals that the suitable formula for ceramics vitreous china is No. 2_4 of Group 2 with sintering temperature 1250°C. Its mixture consists of 0% kaolin, 35% ball clay, 30% feldspar, 20% silica sand and 15% sediment soil. The properties of this formula are 9.4% shrinkage, 9.39 MPa of bending strength, 6.34×10−6/K coefficient of thermal expansion, and 0.66% water absorption.

  16. Comparison of two Nd:YAG laser posterior capsulotomy: cruciate patternvscircular pattern with vitreous strand cutting.

    Science.gov (United States)

    Kim, Jin-Soo; Choi, Jung Yeol; Kwon, Ji-Won; Wee, Won Ryang; Han, Young Keun

    2018-01-01

    To investigate the effects and safety of neodymium: yttrium-aluminium-garnet (Nd:YAG) laser posterior capsulotomy with vitreous strand cutting. A total of 40 eyes of 37 patients with symptomatic posterior capsular opacity (PCO) were included in this prospective randomized study and were randomly subjected to either cruciate pattern or round pattern Nd:YAG posterior capsulotomy with vitreous strand cutting (modified round pattern). The best corrected visual acuity (BCVA), intraocular pressure (IOP), refractive error, endothelial cell count (ECC), anterior segment parameters, including anterior chamber depth (ACD) and anterior chamber angle (ACA) were measured before and 1mo after the laser posterior capsulotomy. In both groups, the BCVA improved significantly ( P pattern group, P =0.001 for the cruciate pattern group); the IOP and ECC did not significantly change. The ACD significantly decreased ( P pattern group and P =0.034 for the cruciate group). The extent of changes in these parameters was not significantly different between the groups. Modified round pattern Nd:YAG laser posterior capsulotomy is an effective and safe method for the treatment of PCO. This method significantly changes the ACD and ACA, but the change in refraction is not significant. Modified round pattern Nd:YAG laser posterior capsulotomy can be considered a good alternative procedure in patients with symptomatic PCO.

  17. Predictors of postoperative bleeding after vitrectomy for vitreous hemorrhage in patients with diabetic retinopathy.

    Science.gov (United States)

    Motoda, Saori; Shiraki, Nobuhiko; Ishihara, Takuma; Sakaguchi, Hirokazu; Kabata, Daijiro; Takahara, Mitsuyoshi; Kimura, Takekazu; Kozawa, Junji; Imagawa, Akihisa; Nishida, Kohji; Shintani, Ayumi; Iwahashi, Hiromi; Shimomura, Iichiro

    2017-12-19

    To clarify the association between perioperative variables and postoperative bleeding in pars plana vitrectomy for vitreous hemorrhage in diabetic retinopathy. The present retrospective study enrolled 72 eyes of 64 patients who were admitted to Osaka University Hospital between April 2010 and March 2014, and underwent vitrectomy for vitreous hemorrhage as a result of diabetic retinopathy. Postoperative bleeding developed in 12 eyes. Using binomial logistic regression analysis, we found that the duration of operation was the only significant variable associated with postoperative bleeding within 12 weeks after vitrectomy. Furthermore, Poisson regression analysis identified fasting blood glucose just before vitrectomy, no treatment with antiplatelet drugs and treatment with antihypertensive drugs, as well as duration of operation, to be significantly associated with the frequency of bleeding within 52 weeks after vitrectomy. Long duration of operation can be used to predict bleeding within both 12 and 52 weeks after vitrectomy. In addition, fasting blood glucose just before vitrectomy, no treatment with antiplatelet drugs and treatment with antihypertensive drugs might be risk factors for postoperative bleeding up to 1 year after vitrectomy. © 2017 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

  18. Persistent hyperplastic primary vitreous: imaging evaluation; Persistencia hiperplastica do vitreo primitivo: avaliacao por metodos de imagem

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, Beatriz Mahmud; Teixeira, Kim-Ir-Sen Santos; Figueiredo, Sizenildo da Silva; Nobrega, Bruno Barcelos da [Universidade Federal de Goias, Goiania (Brazil). Hospital das Clinicas. Dept. de Diagnostico por Imagem]. E-mail: biamjacob@hotmail.com

    2003-06-01

    Persistent hyperplastic primary vitreous (PHPV) is a congenital developmental anomaly of the eye that primarily affects premature infants. PHPV results from failure of regression of the embryogenic primary vitreous and hyaloid vasculature, and proliferation of connective tissue. Three types of PHPV may be found: anterior, posterior and a combination of anterior and posterior. The clinical findings include leukocoria (white pupillary reflex) and microphthalmic eye. This anomaly is usually unilateral and unassociated with other systemic findings. The differential diagnosis between PHPV and other ocular diseases may be difficult due to similar features such as leukocoria, detached retina, retinal folds and cataract. Other diseases with similar features include retinoblastoma, isolated congenital cataract, retinopathy of prematurity and pseudo gliomas or leukocorias. Direct visualization of the remnants of the fetal hyaloid vascular system offers the best evidence of PHPV. However, diagnosis using the ophthalmoscope is sometimes impossible because of opaque tissues. In this circumstance an indirect visualization by ultrasound, computed tomography or magnetic resonance imaging may be useful. These imaging methods provide valuable information for the differentiation from other diseases, particularly retinoblastoma. The authors present a review of the literature and an iconographic study of the imaging findings in patients with PHPV. (author)

  19. Vitreous Detachment

    Science.gov (United States)

    ... to sight-saving treatments and plays a key role in reducing visual impairment and blindness. NEI Home Contact Us A-Z Site Map NEI on Social Media Information in Spanish (Información en español) Website, Social ...

  20. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  1. Two-step technique for posterior optic buttonholing of intraocular lens.

    Science.gov (United States)

    Agarwal, Tushar; Jhanji, Vishal; Singh, Digvijay; Khokhar, Sudarshan

    2014-04-01

    This study aims to describe a two-step surgical technique for placement of a posterior chamber intraocular lens (IOL) in cases with crystalline lens subluxation resulting from non-progressive zonular dialysis. The first stage entails a phacoemulsification with creation of a 4-mm posterior capsular opening using an automated vitrector. The second stage performed 6 weeks later includes an anterior vitrectomy and injection of a foldable three-piece IOL in the sulcus. The haptics of IOL are positioned in the sulcus while the optic is pushed behind the posterior capsular opening therefore "buttonholing" the IOL. Seven eyes of seven patients with posttraumatic zonular dialysis were operated using this technique. Follow-up of all cases revealed a well-centered IOL with good postoperative visual acuity (20/20 to 20/80). Our two-stage surgical technique precludes the insertion of capsular tension ring in cases with non-progressive zonular dialysis. The technique is recommended in the presence of less than or equal to 6 clock hours of zonular dialysis with preexisting posterior capsular tear or herniation of vitreous in the anterior chamber.

  2. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Shin, Jung Hyuck; Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin

    2011-01-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility

  3. Lens decenter and tilt measurement by interferogram

    Science.gov (United States)

    Hung, Min-Wei; Wu, Wen-Hong; Huang, Kuo-Cheng

    2009-11-01

    For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.

  4. [Treatment for penetrating wound caused by metallic intraocular foreign body].

    Science.gov (United States)

    Pienaru, M; Şerban, Ramona; Baltă, F

    2014-01-01

    Penetrating wounds with intraocular foreign body are ophthalmologic emergencies due to their severity and complexity and may require multiple surgeries for final resolution. 30-years-old patient with penetrating wound and metallic intraocular foreign body in the posterior vitreous requires successive operations for IOFB extraction, lensectomy, posterior vitrectomy for rhegmatogenous retinal detachment and then silicone oil extraction with final visual acuity 0, 4 PH.

  5. Prevalence and associations of incomplete posterior vitreous detachment in adult Chinese: the Beijing Eye Study.

    Directory of Open Access Journals (Sweden)

    Lei Shao

    Full Text Available To determine prevalence and associations of incomplete posterior vitreous detachment (PVD.The population-based cross-sectional Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range: 50-93 years. A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD-OCT. Incomplete PVD was differentiated into type 1 (shallow PVD with circular perifoveal vitreous attachment, type 2 (PVD reaching fovea but not foveola, type 3 (shallow PVD with pinpoint vitreous attachment at the foveola, and type 4 (PVD completely detached from the macula, attached to the optic disc.An incomplete PVD was detected in 3948 eyes (prevalence: 60.5±0.6%; 95% Confidence Interval (CI: 59.3%,61.7% of 2198 subjects (67.1±0.8%;95%CI: 65.6%,68.7%. Type 1 PVD was seen in 3090 (78.3% eyes, type 2 PVD in 504 (12.8% eyes, type 3 PVD in 70 (1.8% eyes, and type 4 PVD in 284 (7.2% eyes. Prevalence of incomplete PVD was associated with younger age (P<0.001;OR:0.91, male gender (P<0.001;OR:0.64, rural region of habitation (P<0.001;OR:0.49, larger corneal diameter (P = 0.04;OR:0.91, better best corrected visual acuity (P = 0.02;OR:0.41, and hyperopic refractive error (P<0.001;OR:1.15. The type of incomplete PVD was associated with higher age (P<0.001, urban region of habitation (P<0.001, myopic refractive error (P = 0.001, thinner cornea (P = 0.005, and better best corrected visual acuity (P = 0.056.In adult Chinese in Greater Beijing, prevalence of an incomplete PVD (detected in 67.1% subjects was associated with younger age, male gender, rural region of habitation, larger corneal diameter, better best corrected visual acuity and hyperopic refractive error.

  6. Optomechanical integrated simulation of Mars medium resolution lens with large field of view

    Science.gov (United States)

    Yang, Wenqiang; Xu, Guangzhou; Yang, Jianfeng; Sun, Yi

    2017-10-01

    The lens of Mars detector is exposed to solar radiation and space temperature for long periods of time during orbit, so that the ambient temperature of the optical system is in a dynamic state. The optical and mechanical change caused by heat will lead to camera's visual axis drift and the wavefront distortion. The surface distortion of the optical lens includes the displacement of the rigid body and the distortion of the surface shape. This paper used the calculation method based on the integrated optomechanical analysis, to explore the impact of thermodynamic load on image quality. Through the analysis software, established a simulation model of the lens structure. The shape distribution and the surface characterization parameters of the lens in some temperature ranges were analyzed and compared. the PV / RMS value, deformation cloud of the lens surface and quality evaluation of imaging was achieved. This simulation has been successfully measured the lens surface shape and shape distribution under the load which is difficult to measure on the experimental conditions. The integrated simulation method of the optical machine can obtain the change of the optical parameters brought by the temperature load. It shows that the application of Integrated analysis has play an important role in guiding the designing the lens.

  7. Looking beyond the perfect lens

    International Nuclear Information System (INIS)

    Wee, W H; Pendry, J B

    2010-01-01

    The holy grail of imaging is the ability to see through anything. From the conservation of energy, we can easily see that to see through a lossy material would require lenses with gain. The aim of this paper therefore is to propose a simple scheme by which we can construct a general perfect lens, with gain-one that can restore both the phases and amplitudes of near and far fields.

  8. Gauge Transconjunctival Sutureless Vitrectomy in Eyes with Posteriorly Dislocated Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Hüseyin Dündar

    2013-04-01

    Full Text Available Pur po se: To evaluate the efficacy and safety of 23-gauge (23G pars plana vitrectomy (PPV in dislocated intraocular lens (IOL cases: In early- and late-term follow-up. Ma te ri al and Met hod: In this retrospective study, the medical records of 17 patients who underwent 23 G PPV treatment for dislocated IOL between January 2009 and June 2011 were analyzed. Detailed ophthalmologic examination was performed in all patients; intraoperative and postoperative complications were recorded. Re sults: In this study, mean follow-up time was 9.0 (4-22 months and mean age was 60.8 (8-82 years. Mean time after cataract surgery was variable (mean of 28.3 (0-80 months. Four patients had trauma history, five patients had pseudoexfoliation syndrome, and two patients had pathologic myopia. Dislocated IOL was placed into the sulcus in nine patients (52.9%. In two cases (11.7%, the IOLs were removed, and the patients were left aphakic. In two cases out of other 6 (11.7%, the dislocated IOL was changed with scleral fixation lens, whereas in the other four cases (23.5%, IOL was changed with iris claw lens. One patient (5.8% remained at the same level of vision, while twelve (70.5% cases increased two or more lines in BCVA. The vision was decreased in two cases. Intraocular pressure elevation controlled by medication was observed in one case. For two days, hypotony was observed in one patient. Dis cus si on: 23 G PPV technique is an effective and safe method for removing and repositioning of dislocated IOL in the vitreous. (Turk J Ophthalmol 2013; 43: 99-102

  9. Lens subluxation and retinal dysfunction in a girl with homozygous VSX2 mutation.

    Science.gov (United States)

    Khan, Arif O; Aldahmesh, Mohammed A; Noor, Jawaher; Salem, Ahmed; Alkuraya, Fowzan S

    2015-03-01

    To describe a unique lens subluxation phenotype in a child from a consanguineous family and to determine its genetic basis. Ophthalmologic examination (including ocular biometry and electroretinography [ERG] for the proband) and autozygosity-analysis-guided exome sequencing for the family; confirmatory candidate gene sequencing in the family and ethnically matched controls. An otherwise healthy 3-year-old Saudi Arabian girl with poor vision since birth had smooth irides, lens subluxation, cone-rod dysfunction, and high myopia - features resembling Knobloch syndrome but differing in regard to direction of lens subluxation (superior rather than temporal) and the pattern of chorioretinal atrophy (without vitreous condensations or distinct macular atrophy). Autozygome-guided exome sequencing revealed the girl to harbor a homozygous exon 5 mutation in the ocular transcription factor gene visual homeobox 2 (VSX2) [c.773delA; p.Lys258SerfsX44] that was heterozygous in the unaffected brother and parents and absent in 100 healthy ethnically matched controls and on-line databases. Previously reported VSX2 mutations have affected the DNA-binding domains and only been associated with microphthalmia. Unlike previously reported mutations, the current VSX2 mutation is downstream to the protein's DNA binding domains. The phenotype of this girl is unique and suggests a normal regulatory role for VSX2 in iris, zonule, and cone-rod development. For a consanguineous family with suspected recessive ocular disease but without a clear candidate gene, autozygome-guided exome analysis is a powerful technique, even when only a single patient is affected.

  10. PENETRATING OCULAR INJURY WITH RETAINED INTRAOCULAR FOREIGN BODY FROM DRYWALL.

    Science.gov (United States)

    Syed, Reema; Kim, Sung-Hye; Palacio, Agustina; Nunery, William R; Schaal, Shlomit

    2018-03-23

    To present a case of open globe injury and retained intraocular foreign body secondary to drywall. Interventional case report. A 21-year-old man presented with corneal laceration, iris defect, and vitreous hemorrhage after hammering drywall. Computed tomography scan was negative for intraocular foreign body, but a drywall intraretinal foreign body was found on 25-gauge vitrectomy. Intraoperative findings and 6-month follow-up are presented. Intraocular foreign body must always be suspected in all cases of penetrating ocular trauma. Although magnetic resonance imaging is ideal in diagnosing nonmetallic foreign bodies, computed tomography scan with Hounsfield units should be used in an emergency setting.

  11. Proposal of the system for the biogas purification using vitreous and natural zeolite membranes

    International Nuclear Information System (INIS)

    Ortega Viera, Lianys; Fernández SantanI, Elina; Alfonso Martínez, Félix Enrique; Aguiar RoqueI, Yania; Rodríguez Muñoz, Susana

    2017-01-01

    One way to reduce the effects of climate change is to replace fossil fuels with renewable energy such as biogas, but the amount of hydrogen sulphide in it represents an impediment to its use, because of its negative impacts on human health, materials of construction and the environment, being essential its reduction or elimination. For this reason, it was defined as aim to propose an effective method for the purification of biogas using membranes constructed from vitreous waste materials and natural cuban zeolite. This treatment requires four membranes with their supports and eight valves and could be used by small farmers for the purification of 1.4 m 3 of biogas per day, an amount necessary for the cooking of three meals of a family of five people, being the cost of the biogas purification process equal to 0.06%/m 3 . (author)

  12. Changes in the thermoelectric response of vitreous carbon due to the irradiation by γ-rays

    Science.gov (United States)

    Culebras, M.; Madroñero, A.; Mota, C.; Gómez, C. M.; Amo, Jose M.; Cantarero, A.

    2014-07-01

    In order to study variations in the thermoelectric properties, some commercial glassy carbon samples were subjected to a sequence of steps consisting of a combination of irradiation with γ-rays produced by radioisotopes 60Co, and hydrogen adsorption when the samples were put in an over pressured atmosphere of this gas. With this procedure it was possible to observe that the irradiation decreases the electrical conductivity of glassy carbon samples and the hydrogenation changes the sign of Seebeck coefficient. The material initially is an n-type semiconductor, but with hydrogenation changes to p-type semiconductor. X-ray diffraction analysis showed that the hydrogenated vitreous carbon is more amorphous than the pristine material and the γ-rays irradiation produces changes in the crystallite size and shape.

  13. Preparation, electrochemical characterization and charge-discharge of reticulated vitreous carbon/polyaniline composite electrodes

    International Nuclear Information System (INIS)

    Dalmolin, Carla; Biaggio, Sonia R.; Rocha-Filho, Romeu C.; Bocchi, Nerilso

    2009-01-01

    Polyaniline was electrodeposited onto reticulated vitreous carbon - RVC - in order to obtain a tridimensional composite electrode. Three variations of these electrodes were analysed: a small-anion-doped polyaniline (RVC/Pani), a polyanion-doped polyaniline (RVC/PaniPSS) and a bi-layer type formed by an inner layer of the first electrode and an outer layer of the second one (RVC/Pani/PaniPSS). These composites were characterized by cyclic voltammetry, scanning electronic microscopy and electrochemical impedance spectroscopy. Photomicrographies, voltammetric profiles and impedance data pointed to different morphological and electrochemical characteristics for polyaniline doped with small or large anions, and a mixed behavior for the bi-layer electrodes. Charge-discharge tests for these tridimensional (3D) electrodes, employed as the cathode in lithium batteries, indicated better performance for the RVC/Pani electrode. These RVC composites presented higher specific capacities when compared with those obtained for Pani deposited onto bidimensional substrates.

  14. Leber congenital amaurosis associated with optic disk neovascularization and vitreous hemorrhage.

    Science.gov (United States)

    Kurz, Daryl; Ciulla, Thomas A

    2003-05-01

    To report an unusual case of optic disk neovascularization and vitreous hemorrhage associated with Leber congenital amaurosis (LCA). Interventional case report. A 16-year-old Caucasian girl with a history of LCA presented with decreased vision in her left eye, diffuse retinal pigmentary abnormalities characteristic of LCA, and hemorrhage over the left optic disk and macula. Six months of follow-up revealed optic disk neovascularization. A small amount of neovascularization was noted in the right eye at 6 months. An extensive systemic evaluation indicated no other cause for the neovascularization. Panretinal photocoagulation was performed in both eyes, and subsequently the neovascularization regressed. Leber congenital amaurosis like retinitis pigmentosa, can rarely be associated with neovascularization of the disk, which is amenable to treatment with peripheral photocoagulation if it does not spontaneously regress.

  15. Electron exchange between neutral and ionized impurity iron centers in vitreous arsenic selenide

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, A. V. [Herzen State Pedagogical University of Russia (Russian Federation); Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Egorova, A. Yu. [St.-Petersburg Mining University (Russian Federation); Kiselev, V. S.; Seregin, P. P., E-mail: ppseregin@mail.ru [Herzen State Pedagogical University of Russia (Russian Federation)

    2017-04-15

    Impurity iron atoms in vitreous arsenic-selenide As{sub 2}Se{sub 3} films modified by iron form one-electron donor centers with an ionization energy of 0.24 (3) eV (the energy is counted from the conduction-band bottom). The Fermi level is shifted with an increase in the iron concentration from the mid-gap to the donorlevel position of iron due to the filling of one-electron states of the acceptor type lying below the Fermi level. At an iron concentration of ≥3 at %, the electron-exchange process is observed between neutral and ionized iron centers resulting in a change both in the electron density and in the tensor of the electric-field gradient at iron-atom nuclei with increasing temperature above 350 K.

  16. Defects in electron irradiated vitreous SiO2 probed by positron annihiliation

    International Nuclear Information System (INIS)

    Uedono, Akira; Tanigawa, Shoichiro; Kawano, Takao; Itoh, Hisayoshi

    1994-01-01

    Defects in 3 MeV electron irradiated vitreous SiO 2 (v-SiO 2 ) were probed by the positron annihilation technique. For unirradiated v-SiO 2 specimens, almost all positrons were found to annihilate from positronium (Ps) states. This high formation probability of Ps was attributed to the trapping of positrons by open-space defects. The formation probability of Ps was decreased by the electron irradiation. The observed inhibition of the Ps formation was attributed to the trapping of positrons by point defects introduced and/or activated by the irradiation. From measurements of the lifetime distribution of Ps, it was found that, by the electron irradiation, the mean size of open-space defects was decreased and the size distribution of such defects was broadened. (Author)

  17. Defects in electron irradiated vitreous SiO[sub 2] probed by positron annihiliation

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Tanigawa, Shoichiro (Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science); Kawano, Takao (Tsukuba Univ., Ibaraki (Japan). Radioisotope Centre); Itoh, Hisayoshi (Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment)

    1994-10-10

    Defects in 3 MeV electron irradiated vitreous SiO[sub 2] (v-SiO[sub 2]) were probed by the positron annihilation technique. For unirradiated v-SiO[sub 2] specimens, almost all positrons were found to annihilate from positronium (Ps) states. This high formation probability of Ps was attributed to the trapping of positrons by open-space defects. The formation probability of Ps was decreased by the electron irradiation. The observed inhibition of the Ps formation was attributed to the trapping of positrons by point defects introduced and/or activated by the irradiation. From measurements of the lifetime distribution of Ps, it was found that, by the electron irradiation, the mean size of open-space defects was decreased and the size distribution of such defects was broadened. (Author).

  18. Effect of intravitreal bevacizumab on serum, aqueous, and vitreous humor levels of erythropoietin in patients with proliferative diabetic retinopathy.

    Science.gov (United States)

    Cancarini, A; Costagliola, C; Dell'omo, R; Romano, M; Morescalchi, F; Agnifili, L; Ruggeri, G; Semeraro, F

    2014-12-01

    The aim of this study was to evaluate concentrations of erythropoietin (EPO) and vascular endothelial growth factor (VEGF) in serum, aqueous and vitreous humour of diabetic patients with proliferative retinopathy (PDR) and to verify their possible modifications induced by intravitreal injection of bevacizumab (IVB). This prospective observational study was performed on patients who underwent vitrectomy for proliferative diabetic retinopathy and macular hole or pucker. The study sample consisted of 33 patients with proliferative diabetic retinopathy and 20 non-diabetic patients with macular hole or pucker. EPO and VEGF levels in serum, aqueous and vitreous humour were measured in both groups. In diabetic patients measures were performed before and after IVB. EPO and VEGF levels in aqueous and vitreous humour were markedly increased in diabetic patients with PDR as compared with those recorded in the control group (P<0.001); contrarily, EPO serum levels were similar in both groups (p=not significant). IVB did not affect EPO levels (aqueous 39.1 ± 29.2 vs. 38.6 ± 26.1; vitreous 179.3 ± 88.3 vs. 131.6 ± 67.8; serum 9.2 ± 5.8 vs. 6.9 ± 3.7 mUI/mL); conversely, VEGF concentration significantly decreased 15 days after IVB in serum and ocular fluids (aqueous 141.6 ± 12.3 vs. 81.4 ± 5.4; vitreous 180.4 ± 45.8 vs. 95.8 ± 23.6; serum 113.9 ± 52.8 vs. 73.2 ± 65.6 mUI/mL). These findings demonstrate that the production of VEGF and EPO is regulated by different mechanisms. Intraocular levels of EPO in diabetic patients were significantly higher than those recorded in serum, suggesting a local production. In addition, bevacizumab does not influence intraocular levels of EPO.

  19. Valorization of vitreous China waste to EMT/FAU, FAU and Na-P zeotype materials.

    Science.gov (United States)

    Maatoug, Nesrine; Delahay, Gérard; Tounsi, Hassib

    2018-04-01

    In this study, Na-X, Na-P, SOD and EMT/FAU zeotype materials have been prepared from vitreous China waste by conventional hydrothermal route and alkaline fusion prior to hydrothermal synthesis. The conventional route has shown its limits in the activation of the waste in the chosen experimental conditions, [NaOH] = 3.5 M and T = 60 °C. The amorphous phase of vitreous China waste plays an important role during the zeolitization process because it easily dissolves into the alkaline solution compared to crystalline phases like quartz and mullite. By the conventional route, Na-X and Na-P1 and SOD zeolites were obtained. The alkaline fusion step using NaOH as mineralizer at 550 °C converted the waste to highly active soluble aluminate and silicate salts. The fused material was mixed with distilled water to have liquid to solid ratio L/S = 5, under vigorous stirring at room temperature for 1 day. The obtained gel with molar composition of 7.0 Na 2 O: 1.0 Al 2 O 3 : 4.8 SiO 2 : 209.4 H 2 O was converted by hydrothermal crystallization at 60 °C to nanosized EMT/FAU zeotype and geopolymeric amorphous aluminosilicate material. With the increase of fusion time, there is a decrease of the amount of EMT-type zeolite. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers

    Directory of Open Access Journals (Sweden)

    Yong Wei

    2017-12-01

    Full Text Available By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU.

  1. The current status of eye lens dose measurement in interventional cardiology personnel in Thailand.

    Science.gov (United States)

    Krisanachinda, Anchali; Srimahachota, Suphot; Matsubara, Kosuke

    2017-06-01

    Workers involved in interventional cardiology procedures receive high eye lens doses if radiation protection tools are not properly utilized. Currently, there is no suitable method for routine measurement of eye dose. In Thailand, the eye lens equivalent doses in terms of Hp(3) of the interventional cardiologists, nurses, and radiographers participating in interventional cardiology procedures have been measured at 12 centers since 2015 in the pilot study. The optically stimulated luminescence (OSL) dosimeter was used for measurement of the occupational exposure and the eye lens dose of 42 interventional cardiology personnel at King Chulalongkorn Memorial Hospital as one of the pilot centers. For all personnel, it is recommended that a first In Light OSL badge is placed at waist level and under the lead apron for determination of Hp(10); a second badge is placed at the collar for determination of Hp(0.07) and estimation of Hp(3). Nano Dots OSL dosimeter has been used as an eye lens dosimeter for 16 interventional cardiology personnel, both with and without lead-glass eyewear. The mean effective dose at the body, equivalent dose at the collar, and estimated eye lens dose were 0.801, 5.88, and 5.70 mSv per year, respectively. The mean eye lens dose measured by the Nano Dots dosimeter was 8.059 mSv per year on the left eye and 3.552 mSv per year on the right eye. Two of 16 interventional cardiologists received annual eye lens doses on the left side without lead glass that were higher than 20 mSv per year, the new eye lens dose limit as recommended by ICRP with the risk of eye lens opacity and cataract.

  2. Primary intraocular lens implantation for penetrating lens trauma in Africa.

    Science.gov (United States)

    Bowman, R J; Yorston, D; Wood, M; Gilbert, C; Foster, A

    1998-09-01

    This study aimed to audit the surgical strategy of primary posterior chamber intraocular lens implantation for cases of recent penetrating trauma involving the lens in an African population. Retrospective, noncomparative case series. Seventy-two cases are reported, including all patients who underwent primary intraocular lens implantation for traumatic cataract extraction performed within 1 month of injury between 1988 and 1996. Demographic characteristics and follow-up attendance rates are analyzed. Surgical technique and the occurrence of intraoperative and postoperative complications are reported. Visual outcomes are reported with detailed analysis for cases of poor visual outcome. Mean age was 14.3 years (standard deviation = 11.1), 57 (79%) were male and 15 (21%) were female (chi-square = 23.66, P capsule had been breached by the trauma in 27 (38%) cases, and 15 of these required anterior vitrectomy. Capsular fixation of the implant was achieved in 49% of patients, the remainder having sulcus fixation. Intraoperative rupture of the posterior capsule occurred in four cases. The only common postoperative complication was acute fibrinous anterior uveitis, which occurred in 29 (40%) patients, and 32% of patients followed up for at least 6 months required secondary posterior capsulotomy. This was more common in younger patients (chi-square = 4.2, P < 0.05). Corrected postoperative visual acuities were available for 51 patients, of which 71% achieved 20/60 or better visual acuity. Patients 6 years of age or younger were less likely to achieve 20/60 (chi-square = 6.61, P = 0.01). This surgical strategy has proved successful, producing good visual results and causing no sight-threatening complications. Primary posterior capsulotomy may be appropriate for younger patients.

  3. Research on one manual zoom liquid lens

    Science.gov (United States)

    Zhao, Cunhua; Shi, Yongpeng; Li, Wenjiao; Li, Congcong

    2011-11-01

    In liquid zoom lens, the accurate fixed-focus location needs the accurate calculation of focal length. That is to say, the accurate calculation of surface curvature must be obtained. Therefore, the research of their relation in liquid zoom lens becomes extremely important which has a directly theoretical instruction for the design of liquid zoom lenses. In our paper, the relation is studied. A manual liquid lens is reported which has upper and nether components with specificaton Φ12×5mm. The zoom lens is obtained by the upper component circumvolving down into the nether components.

  4. Numerical analyses of planer plasmonic focusing lens

    Science.gov (United States)

    Chou, Yen-Yu; Lee, Yeeu-Chang

    2018-03-01

    The use of polystyrene (PS) sphere lithography has been widely applied in the fabrication of micron and nano structures, due to their low cost and ease of fabrication in large scale applications. This study evaluated the feasibility of plasmonic lens base on metal thin films with nanohole structures fabricated by using PS sphere lithography through three-dimensional (3D) finite difference time domain (FDTD) method. We calculated the intensity profile of lens with various wavelength of incident light, lens size, cutting positions, diameters of nanohole, and periods of nanohole to investigate the geometric parameters influence on the focusing properties of the plasmonic lens.

  5. Multiple methods of surgical treatment combined with primary IOL implantation on traumatic lens subluxation/dislocation in patients with secondary glaucoma

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2014-04-01

    Full Text Available AIM:To describe clinical findings and complications from cases of traumatic lens subluxation/dislocation in patients with secondary glaucoma, and discuss the multiple treating methods of operation combined with primary intraocular lens (IOL implantation.METHODS:Non-comparative retrospective observational case series. Participants:30 cases (30 eyes of lens subluxation/dislocation in patients with secondary glaucoma were investigated which accepted the surgical treatment by author in the Ophthalmology of Xi''an No.4 Hospital from 2007 to 2011. According to the different situations of lens subluxation/dislocation, various surgical procedures were performed such as crystalline lens phacoemulsification, crystalline lens phacoemulsification combined anterior vitrectomy, intracapsular cataract extraction combined anterior vitrectomy, lensectomy combined anterior vitrectomy though peripheral transparent cornea incision, pars plana lensectomy combined pars plana vitrectomy, and intravitreal cavity crystalline lens phacofragmentation combined pars plana vitrectomy. And whether to implement trabeculectomy depended on the different situations of secondary glaucoma. The posterior chamber intraocular lenses (PC-IOLs were implanted in the capsular-bag or trassclerally sutured in the sulus decided by whether the capsular were present. Main outcome measures:visual acuity, intraocular pressure, the situation of intraocular lens and complications after the operations.RESULTS: The follow-up time was 11-36mo (21.4±7.13. Postoperative visual acuity of all eyes were improved; 28 cases maintained IOP below 21 mm Hg; 2 cases had slightly IOL subluxation, 4 cases had slightly tilted lens optical area; 1 case had postoperative choroidal detachment; 4 cases had postoperative corneal edema more than 1wk, but eventually recovered transparent; 2 cases had mild postoperative vitreous hemorrhage, and absorbed 4wk later. There was no postoperative retinal detachment, IOL

  6. Exchange of tears under a contact lens is driven by distortions of the contact lens.

    Science.gov (United States)

    Maki, Kara L; Ross, David S

    2014-12-01

    We studied the flow of the post-lens tear film under a soft contact lens to understand how the design parameters of contact lenses can affect ocular health. When a soft contact lens is inserted, the blinking eyelid causes the lens to stretch in order to conform to the shape of the eye. The deformed contact lens acts to assume its un-deformed shape and thus generates a suction pressure in the post-lens tear film. In consequence, the post-lens tear fluid moves; it responds to the suction pressure. The suction pressure may draw in fresh fluid from the edge of the lens, or it may eject fluid there, as the lens reassumes its un-deformed shape. In this article, we develop a mathematical model of the flow of the post-lens tear fluid in response to the mechanical suction pressure of a deformed contact lens. We predict the amount of exchange of fluid exchange under a contact lens and we explore the influence of the eye's shape on the rate of exchange of fluid. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  7. Upregulation of Mir-21 Levels in the Vitreous Humor Is Associated with Development of Proliferative Vitreoretinal Disease.

    Directory of Open Access Journals (Sweden)

    Ayumi Usui-Ouchi

    Full Text Available MicroRNAs (miRNAs are small noncoding RNAs that regulate gene expression by post-transcriptional inhibition of mRNA translation. Dysregulation of miRNAs, including circulating miRNAs, has been reported to play an important role in the development of various diseases, including fibrotic diseases. Aberrant expression of miRNAs in the vitreous humor of vitreoretinal diseased eyes has been reported. However, the expression pattern of miRNAs present in the vitreous humor of proliferative vitreoretinal disease (PVD patients, including proliferative diabetic retinopathy (PDR, and proliferative vitreoretinopathy (PVR, remains unknown. To investigate the factors important for the development of PVD, we characterized the miRNAs present in the vitreous humor of PVD patients and analyzed the expression profiles of 377 miRNAs using quantitative polymerase chain reaction-based miRNA arrays. The expression of a specific subset of miRNAs, previously reported to be associated with the development of angiogenesis and fibrosis, was significantly altered in the vitreous of PVD patients. Among these miRNAs, we identified miR-21 as a candidate fibrotic miRNA with an important role in the pathogenesis of PVD. Increased miR-21 levels in the vitreous were associated with retinal fibrosis, including PVR and PDR. Because epithelial-mesenchymal transition (EMT of retinal pigment epithelial cells (RPECs plays a critical role in retinal fibrosis, the expression of miR-21 in human RPECs was determined. Its expression in RPECs was induced by transforming growth factor-β, a key growth factor involved in fibrogenesis, and was enhanced by high glucose culture conditions, suggesting that miR-21 expression positively correlates with disease progression. Gain- and loss-of-function studies revealed that miR-21 promoted cell proliferation and migration of ARPE-19 cells without affecting EMT-related gene expression. Together, our studies have identified miR-21 as a potential disease

  8. [Study on the setup of a new technique of tissue and cell culture for vitreous fluid of vitrectomy].

    Science.gov (United States)

    Li, Gen-lin; Liu, Yue-yue; Zhang, Xiang; Zhang, Cheng-yue; Wang, Liang-hai

    2008-12-01

    To setup a new technique of tissue and cell culture for vitreous aspirates. Experiment study. Specimens used for supporting new culture technique were selected based on random digit table. Thirty cases with rhegmatogenous retinal detachment (RRD) and forty-eight with proliferative diabetic retinopathy (PDR), which undergoing primary pars plana vitrectomy, were selected randomly and included in the study. After being antiphase stained with fluorescein-natrium (0.5%) and digested with hyaluronidase (10(5) U/L) combined with collagenase I (10(6) U/L) for removing vitreous gel, sediment of vitreous fluid after centrifugation were inoculated into standard culturing bottle with which polylysine (0.01%) was pre-set. The bottle which contained F12 medium with 30% fetal bovine serum was placed upside down for 24 hours and consecutively upside for 6 days. During which, F12 medium was replaced once in half volume, and cell growth along the edge of sedimentary membrane was observed at time of the 3rd and the 6th day after upside culture. Under condition of pre-setting by polylysine (0.01%) and being placed upside down for 24 hours, pieces from vitreous fluids could adhere to the bottom of bottle in a way of semi-xerosis with adherence rate of 100% (78/78). No bacteria, fungus and mycoplasma contamination was found within 7 days. Antiphase stained with fluorescein-natrium (0.5%) and digested with hyaluronidase (10(5) U/L) combined with collagenase I (10(6) U/L) for 30 minutes, vitreous gel in 78 specimens could be digested (78/78). Cell emigration could be found in edge area of some pieces of vitreous fluid and cell growth as well as proliferation was shown. In 30 specimens of RRD, cell growth rate were 43.33% (13/30). In 48 specimens of PDR, cell growth rate were 37.50% (18/48). Concerning PDR phase V (PDR-V), cell growth rate reach 41.67% (10/24). Enzymolysis with upside down and semi-xerosis could ensure good adherence of membrane, moreover, no contamination and obvious cell

  9. [Acanthamoeba isolation from contact lens solution of contact lens wearers without keratitis].

    Science.gov (United States)

    Watanabe, R; Ishibashi, Y; Hommura, S; Ishii, K

    1994-05-01

    Acanthamoeba keratitis seems to be associated with wearing contact lenses. As controls, we surveyed contact lens wearers without keratitis. Contact lens solutions of 93 persons were examined in order to identify risk factors for contamination by Acanthamoeba. Therefore, the contact lens disinfection system and storage schedules were studied in each case. Acanthamoeba organisms were isolated from 4 specimens (4.3%). The incidence of Acanthamoeba was higher in specimens of soft contact lens solution than in those of hard contact lens solution, and all the Acanthamoeba positive cases had been using tap water.

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

    Science.gov (United States)

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

    2009-10-01

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

  11. Protection of the eye lens

    International Nuclear Information System (INIS)

    2015-01-01

    The limit of radiation exposure for eye lens is going to decrease dramatically from 150 to 20 mSv as a transposition into the French law of a CIPR (International Commission for Radiation Protection) directive. Sanitary studies have shown that radiologists are more likely by a factor of 3.8 to get eye lens opacities than the rest of the population. The wearing of protective glasses is recommended and in order to get a better monitoring of the radiation dose new dosimeters have been designed, they can be worn on the glass frame of directly stuck on the skin near the eyes. A study has shown that veterinary surgeons that are accustomed to stay near animals to keep them quiet during radiological exams are prone to receive high doses as well as physicians that use hypnosis to decrease the level of anxiety of their patients during radiological exams. Radiation exposure of radiologists can be mitigated through: the use of protective shields and equipment and the optimization of the dose delivered to the patient. (A.C.)

  12. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    Kritchman, E.M.

    1979-01-01

    A new linear convex Fresnel lens with its groove side down is described. The design philosophy is similar to the highly concentrating two focal Fresnel lens but including a correction for chromatic aberration. A solar concentration ratio as high as 80 is achieved. For wide acceptance angles the concentration nears the theoretical maximum. (author)

  13. Modified suturing contact lens for penetrating keratoplasty.

    Science.gov (United States)

    Kramer, S G; Stewart, H L

    1978-11-01

    The authors have previously described a suturing contact lens that protects the corneal endothelium by aiding in the maintenance of the anterior chamber during penetrating keratoplasty. This report describes structural modifications of the suturing contact lens, which improve its stability and effectiveness. An additional configuration for use in corneal lacerations is presented.

  14. Charged black lens in de Sitter space

    Science.gov (United States)

    Tomizawa, Shinya

    2018-02-01

    We obtain a charged black lens solution in the five-dimensional Einstein-Maxwell-Chern-Simons theory with a positive cosmological constant. It is shown that the solution obtained here describes the formation of a black hole with the spatial cross section of a sphere from that of the lens space of L (n ,1 ) in five-dimensional de Sitter space.

  15. Contact Lens Use in the Civil Airman Population

    National Research Council Canada - National Science Library

    Nakagawara, Van

    2002-01-01

    ...) aeromedical certificate. Although contact lens technology has advanced dramatically in recent years, the aviation environment may still have adverse effects on contact lens performance in some flight situations...

  16. Corrected electrostatic lens systems for ion beams

    International Nuclear Information System (INIS)

    Dalgish, R.L.

    1981-01-01

    Recent work in our laboratory has introduced a new class of electrostatic focus forming element for beams, the ELCO lens. It compares favourably with the electrostatic and magnetic quadrupole elements conventionally used for microbeam formation. The ELCO lens does however have disadvantages associated with apertures and alignment. We have continued with the development of ion beam lenses and have evolved a further class of lens element which eliminates aperture and alignment problems. This new element can be combined like optical lenses into an aberration corrected system. Experimental measurement on the basic lens element has confirmed mathematical analysis of ion trajectories through the element. This mathematical analysis predicts that the basic element can be combined into a corrected lens system for, either: (1) high resolution microprobe formation with intrinsic rastering ability, the spot size limited only by the beam properties; or (2) high quality image formation with large magnification/demagnification ratio and wide angular aperture. (orig.)

  17. Biologically inspired LED lens from cuticular nanostructures of firefly lantern

    Science.gov (United States)

    Kim, Jae-Jun; Lee, Youngseop; Kim, Ha Gon; Choi, Ki-Ju; Kweon, Hee-Seok; Park, Seongchong; Jeong, Ki-Hun

    2012-01-01

    Cuticular nanostructures found in insects effectively manage light for light polarization, structural color, or optical index matching within an ultrathin natural scale. These nanostructures are mainly dedicated to manage incoming light and recently inspired many imaging and display applications. A bioluminescent organ, such as a firefly lantern, helps to out-couple light from the body in a highly efficient fashion for delivering strong optical signals in sexual communication. However, the cuticular nanostructures, except the light-producing reactions, have not been well investigated for physical principles and engineering biomimetics. Here we report a unique observation of high-transmission nanostructures on a firefly lantern and its biological inspiration for highly efficient LED illumination. Both numerical and experimental results clearly reveal high transmission through the nanostructures inspired from the lantern cuticle. The nanostructures on an LED lens surface were fabricated by using a large-area nanotemplating and reconfigurable nanomolding with heat-induced shear thinning. The biologically inspired LED lens, distinct from a smooth surface lens, substantially increases light transmission over visible ranges, comparable to conventional antireflection coating. This biological inspiration can offer new opportunities for increasing the light extraction efficiency of high-power LED packages. PMID:23112185

  18. Si-O-Si bond-angle distribution in vitreous silica from first-principles 29Si NMR analysis

    International Nuclear Information System (INIS)

    Mauri, Francesco; Pasquarello, Alfredo; Pfrommer, Bernd G.; Yoon, Young-Gui; Louie, Steven G.

    2000-01-01

    The correlation between 29 Si chemical shifts and Si-O-Si bond angles in SiO 2 is determined within density-functional theory for the full range of angles present in vitreous silica. This relation closely reproduces measured shifts of crystalline polymorphs. The knowledge of the correlation allows us to reliably extract from the experimental NMR spectrum the mean (151 degree sign ) and the standard deviation (11 degree sign ) of the Si-O-Si angular distribution of vitreous silica. In particular, we show that the Mozzi-Warren Si-O-Si angular distribution is not consistent with the NMR data. This analysis illustrates the potential of our approach for structural determinations of silicate glasses. (c) 2000 The American Physical Society

  19. THEORETICAL GAS CONCENTRATIONS ACHIEVING 100% FILL OF THE VITREOUS CAVITY IN THE POSTOPERATIVE PERIOD: A Gas Eye Model Study.

    Science.gov (United States)

    Williamson, Tom H; Guillemaut, Jean-Yves; Hall, Sheldon K; Hutter, Joseph C; Goddard, Tony

    2017-12-11

    To determine the concentrations of different gas tamponades in air to achieve 100% fill of the vitreous cavity postoperatively and to examine the influence of eye volume on these concentrations. A mathematical model of the mass transfer dynamics of tamponade and blood gases (O2, N2, and CO2) when injected into the eye was used. Mass transfer surface areas were calculated from published anatomical data. The model has been calibrated from published volumetric decay and composition results for three gases sulphahexafluoride (SF6), hexafluoroethane (C2F6), or perfluoropropane (C3F8). The concentrations of these gases (in air) required to achieve 100% fill of the vitreous cavity postoperatively without an intraocular pressure rise were determined. The concentrations were calculated for three volumes of the vitreous cavity to test whether ocular size influenced the results. A table of gas concentrations was produced. In a simulation of pars plana vitrectomy operations in which an 80% to 85% fill of the vitreous cavity with gas was achieved at surgery, the concentrations of the 3 gases in air to achieve 100% fill postoperatively were 10% to 13% for C3F8, 12% to 15% for C2F6, and 19% to 25% for SF6. These were similar to the so-called "nonexpansive" concentrations used in the clinical setting. The calculations were repeated for three different sizes of eye. Aiming for an 80% fill at surgery and 100% postoperatively, an eye with a 4-mL vitreous cavity required 24% SF6, 15% C2F6, or 13% C3F8; 7.2 mL required 25% SF6, 15% C2F6, or 13% C3F8; and 10 mL required 25% SF6, 16% C2F6, or 13% C3F8. When using 100% gas (e.g., used in pneumatic retinopexy), to achieve 100% fill postoperatively, the minimum vitreous cavity fill at surgery was 43% for SF6, 29% for C2F6, and 25% for C3F8 and was only minimally changed by variation in the size of the eye. A table has been produced, which could be used for surgical innovation in gas usage in the vitreous cavity. It provides concentrations

  20. Treatment of vitreous hemorrhage in Rh-positive patients by intravitreal injection of anti-Rho-immunoglobulin.

    Science.gov (United States)

    Morawiecki, J; Geursen, R G

    1985-01-01

    22 Rh-positive patients suffering from vitreous hemorrhage caused by injuries to the eye, hypertension, or associated with subarachnoid hemorrhage, were treated with anti-Rh-immunoglobulin by intravitreal injection. 8 patients (36.4%) needed only one immunoglobulin injection and rapidly regained their former visual acuity. In 2 cases with repeated hemorrhage the result of the treatment was not satisfactory. The incidence of adverse effects was low.

  1. PERSISTENT OVERPRODUCTION OF INTRAOCULAR VASCULAR ENDOTHELIAL GROWTH FACTOR AS A CAUSE OF LATE VITREOUS HEMORRHAGE AFTER VITRECTOMY FOR PROLIFERATIVE DIABETIC RETINOPATHY.

    Science.gov (United States)

    Wakabayashi, Yoshihiro; Usui, Yoshihiko; Tsubota, Kinya; Ueda, Shunichiro; Umazume, Kazuhiko; Muramatsu, Daisuke; Goto, Hiroshi

    2017-12-01

    The purpose of this study was to investigate whether vitreous levels of vascular endothelial growth factor (VEGF) predict late vitreous hemorrhage (VH) after vitrectomy for proliferative diabetic retinopathy, and how VEGF level changes in patients with postoperative late VH. Eighty-five eyes of 68 patients with proliferative diabetic retinopathy who underwent vitrectomy were analyzed retrospectively. Vitreous samples were collected from eyes undergoing primary vitrectomy and from eyes with late VH undergoing second vitrectomy. Vitreous VEGF levels were measured using enzyme-linked immunosorbent assay. The relationship between VEGF level and late VH (>4 weeks) occurring during follow-up as well as clinical findings, and changes in VEGF level in eyes with late VH undergoing second vitrectomy were analyzed. Late VH occurred in 20 (24%) of 85 eyes, and 9 eyes required second vitrectomy. Vitreous levels of VEGF were significantly higher (median: 1,945 pg/mL; P diabetic retinopathy (odds ratio: 20.8, 95% confidence interval: 2.72-159.47; P = 0.003). Vitreous VEGF level at second vitrectomy in patients with late VH was significantly lower compared with that at primary vitrectomy, but remained elevated (median: 1,610 pg/mL; P = 0.023). In patients with proliferative diabetic retinopathy, high intraocular VEGF level at primary vitrectomy was identified as an independent risk factor of postoperative late VH. Persistent overproduction of intraocular VEGF may be associated with postoperative late VH.

  2. Phototoxicity and cytotoxicity of fullerol in human lens epithelial cells

    International Nuclear Information System (INIS)

    Roberts, Joan E.; Wielgus, Albert R.; Boyes, William K.; Andley, Usha; Chignell, Colin F.

    2008-01-01

    The water-soluble, hydroxylated fullerene [fullerol, nano-C 60 (OH) 22-26 ] has several clinical applications including use as a drug carrier to bypass the blood ocular barriers. We have assessed fullerol's potential ocular toxicity by measuring its cytotoxicity and phototoxicity induced by UVA and visible light in vitro with human lens epithelial cells (HLE B-3). Accumulation of nano-C 60 (OH) 22-26 in the cells was confirmed spectrophotometrically at 405 nm and cell viability estimated using MTS and LDH assays. Fullerol was cytotoxic to HLE B-3 cells maintained in the dark at concentrations higher than 20 μM. Exposure to either UVA or visible light in the presence of > 5 μM fullerol-induced phototoxic damage. When cells were pretreated with non-toxic antioxidants: 20 μM lutein, 1 mM N-acetyl cysteine, or 1 mM L-ascorbic acid prior to irradiation, only the singlet oxygen quencher-lutein significantly protected against fullerol photodamage. Apoptosis was observed in lens cells treated with fullerol whether or not the cells were irradiated, in the order UVA > visible light > dark. Dynamic light scattering (DLS) showed that in the presence of the endogenous lens protein α-crystallin, large aggregates of fullerol were reduced. In conclusion, fullerol is both cytotoxic and phototoxic to human lens epithelial cells. Although the acute toxicity of water-soluble nano-C 60 (OH) 22-26 is low, these compounds are retained in the body for long periods, raising concern for their chronic toxic effect. Before fullerols are used to deliver drugs to the eye, they should be tested for photo- and cytotoxicity in vivo

  3. Change of ranibizumab-induced human vitreous protein profile in patients with proliferative diabetic retinopathy based on proteomics analysis.

    Science.gov (United States)

    Zou, Chen; Han, Changjing; Zhao, Minjie; Yu, Jingjing; Bai, Lin; Yao, Yuan; Gao, Shuaixin; Cao, Hui; Zheng, Zhi

    2018-01-01

    Preoperative treatment of anti-vascular endothelial growth factor (VEGF) agents is extensively used in proliferative diabetic retinopathy (PDR), but the molecular mechanism is not fully understood. The objective of this research is to observe change of protein profile induced by ranibizumab (an anti-VEGF agent) in vitreous humor from PDR patients and reveal the effects of anti-VEGF treatment on PDR. A proteomic method was used to identify differentially expressed proteins in vitreous humor. Untreated PDR patients were defined as PDR group, while those who treated with intravitreal injection of ranibizumab (IVR) were defined as IVR. Gene Ontology (GO) annotation and REACTOME pathways were obtained from DAVID Bioinformatics Resources. Intravitreal level of apolipoprotein C-I (APOC1), serpin peptidase inhibitor clade A member 5 (SERPINA5), tissue inhibitor of metalloproteinases (TIMP2), and keratin 1 (KRT1) were determined by enzyme-linked immuno sorbent assay (ELISA). 339 differentially expressed proteins were identified in response to IVR. The most notable GO annotation describes the altered proteins was "innate immune response". The most notable REACTOME pathway was "platelet degranulation". ELISA result showed increased level of APOC1, SERPINA5, KRT1 and a decreased level of TIMP2 in PDR group compared with IVR. In addition to decreasing VEGF level, ranibizumab is associated with change of human vitreous protein profile in patients with PDR, in which the differential proteins are involved in immune response, platelet degranulation, complement activation etc., suggesting that the effects of VEGF are involved in these signaling pathways.

  4. Correlation of Vitreous Vascular Endothelial Growth Factor and Uric Acid Concentration Using Optical Coherence Tomography in Diabetic Macular Edema

    Directory of Open Access Journals (Sweden)

    Libuse Krizova

    2015-01-01

    Full Text Available Purpose. We investigated two factors linked to diabetic macular edema (DME, vitreous and serum levels of vascular endothelial growth factor (VEGF and uric acid (UA in patients with DME, and compared the results with changes in optical coherence tomography (OCT and visual acuity (VA. Methods. A prospective study of 29 eyes, 16 cystoid DME and nonproliferative diabetic retinopathy (DR and 13 nondiabetic controls. Biochemical analysis of vitreous and serum samples was performed and OCT scans were graded according to central retinal thickness (CRT, cube volume (CV, cube average thickness (CAT, and serous retinal detachment (SRD. Results. In DME group, intravitreal concentrations of VEGF (p<0.001, UA (p=0.038, and total protein (p<0.001 were significantly higher than in control group. In DME subjects, intravitreal UA correlated significantly with intravitreal VEGF (ƍ = 0.559, p=0.03 but not with total vitreous protein and serum UA. Increased intravitreal VEGF in DME group correlated with increase in CV (ƍ = 0.515/p=0.041. None of the OCT parameters correlated with the VA. Conclusions. The results suggest that the CV might be assessor of anti-VEGF therapy efficacy. Second, apart from VEGF, the role of UA in the pathogenesis and progression of DR should be considered.

  5. Measurement of amino acid levels in the vitreous humor of rats after chronic intraocular pressure elevation or optic nerve transection.

    Science.gov (United States)

    Levkovitch-Verbin, Hana; Martin, Keith R G; Quigley, Harry A; Baumrind, Lisa A; Pease, Mary Ellen; Valenta, Danielle

    2002-10-01

    To investigate whether the levels of free amino acids and protein in the vitreous of rat eyes are altered with chronic intraocular pressure (IOP) elevation or after optic nerve transection. The concentrations of 20 amino acids in the vitreous humor were measured by high-performance liquid chromatography in both eyes of 41 rats with unilateral IOP elevation induced by translimbal photocoagulation. Eyes were studied 1 day and 1, 2, 4, and 9 weeks after initial IOP elevation. The same amino acids were measured in 41 rats 1 day and 2, 4, and 9 weeks after unilateral transection of the orbital optic nerve. The intravitreal protein level was assayed in additional 22 rats with IOP elevation and 12 rats after nerve transection. Two masked observers evaluated the amount of optic nerve damage with a semiquantitative, light-microscopic technique. In rats with experimental glaucoma, amino acid concentrations were unchanged 1 day after treatment. At 1 week, 4 of 20 amino acids (aspartate, proline, alanine, and lysine) were higher than in control eyes ( 0.05). Vitreous protein level was significantly higher in glaucomatous eyes than their paired controls at 1 day ( 0.01).

  6. Investigation of lens morphology and mechanical characteristics of lens capsule and lens nucleus in patients with agerelated and diabetic cataract

    Directory of Open Access Journals (Sweden)

    A. S. Tishkova

    2014-07-01

    Full Text Available Purpose: To investigate the influence of carbohydrate metabolism on the structure and mechanical properties of the lens capsule and nucleus.Methods: Human lens pathology was studied in different forms of cataract. 220 patients with a cataract (220 eyes were included in this study. Morphological, immunohystological and immunocytochemical investigations of lens substance (antibodies to a- (a-А and a-В, b-, g- crystallines, spectroscopic analyses of smears and morphometric analyses of slices, investigation of lens morphology and mechanical caracteristics of lens capsule and lens nucleus were performed.Results: The capsule of the lens in patients with senile cataract contains more Na+, Cl-. The capsule of the lens in patients with senile cataract contains more Ca2+, O. Mechanical strength of the capsule in the case of diabetes mellitus was lower comparatively with senile cataract in the same age groups. More significant expression of a-В and b-crystallines was found in patients with diabetes mellitus comparatively with patients with age-related cataract. Morphological features were founded in patients with cortical and nuclear forms of senile cataract and the diabetic cataract.Conclusion: During surgery (ultrasonic microcoaxial phacoemulsification the equivalent of ultrasound was recorded. Lower density of the lens nucleus of patients with diabetes mellitus made it possible to use lower energy parameters. Using the torsion ultrasound in those cases allowed us to decrease the influence of ultrasound on eye tissues and reduce the time of achieving the maximum BCVA in the postsurgical period.

  7. Investigation of lens morphology and mechanical characteristics of lens capsule and lens nucleus in patients with agerelated and diabetic cataract

    Directory of Open Access Journals (Sweden)

    A. S. Tishkova

    2013-01-01

    Full Text Available Purpose: To investigate the influence of carbohydrate metabolism on the structure and mechanical properties of the lens capsule and nucleus.Methods: Human lens pathology was studied in different forms of cataract. 220 patients with a cataract (220 eyes were included in this study. Morphological, immunohystological and immunocytochemical investigations of lens substance (antibodies to a- (a-А and a-В, b-, g- crystallines, spectroscopic analyses of smears and morphometric analyses of slices, investigation of lens morphology and mechanical caracteristics of lens capsule and lens nucleus were performed.Results: The capsule of the lens in patients with senile cataract contains more Na+, Cl-. The capsule of the lens in patients with senile cataract contains more Ca2+, O. Mechanical strength of the capsule in the case of diabetes mellitus was lower comparatively with senile cataract in the same age groups. More significant expression of a-В and b-crystallines was found in patients with diabetes mellitus comparatively with patients with age-related cataract. Morphological features were founded in patients with cortical and nuclear forms of senile cataract and the diabetic cataract.Conclusion: During surgery (ultrasonic microcoaxial phacoemulsification the equivalent of ultrasound was recorded. Lower density of the lens nucleus of patients with diabetes mellitus made it possible to use lower energy parameters. Using the torsion ultrasound in those cases allowed us to decrease the influence of ultrasound on eye tissues and reduce the time of achieving the maximum BCVA in the postsurgical period.

  8. Development of a thin film vitreous bond based composite ceramic coating for corrosion and abrasion services

    International Nuclear Information System (INIS)

    Franke, B.

    2003-01-01

    IPC has been involved with the Alberta Research Council in developing a vitreous bond (VB) - based composite ceramic fluoropolymer coating technology. Compared to the present state of the art which is based on a hard discontinuous phase (ceramic particles) suspended in a soft continuous matrix (fluoropolymer mix) the novelty of our approach consists of designing a composite system in which both the ceramic and the fluoropolymer phases are continuous. The ceramic matrix will provide the strength and the erosion resistance for the fluoropolymer matrix even at high temperatures. The ceramic formulation employed is not affected by temperatures up to 500 o F while the fluoropolymer matrix provides a corrosion protection seal for the ceramic matrix. The inherent flexibility of the polymer matrix will protect against brittle fractures that may develop by handling or impact. Therefore the composite coating is able to withstand the deformation of the substrate without chipping or disbanding. The fluoropolymer matrix also provides dry lubrication properties further enhancing the erosion resistance of the ceramic phase. The thickness of the coating is very thin, in the 25 to 100 micron range. In summary, the coating technology is able to provide the following features: Corrosion protection levels similar to those of fluoropolymer coatings; Erosion resistance similar to that of ceramic coatings; Price comparable to that of polymer coatings; Exceptional wear resistance properties; and Capability for coating complicated shapes internally or externally or both. This paper will discuss the theory and development of this new technology and the resultant coating and potential properties. (author)

  9. Evaluation of porous vitreous carbon or silicon implants by radiology in rat's skull

    International Nuclear Information System (INIS)

    Vaccari-Mazzetti, Marcelo Paulo; Kobata, Celio Toshiro; Fabiani, Paulo; Martins, Dulce Maria Fonseca Soares; Gomes, Paulo de Oliveira; Martins, Jose Luiz

    2008-01-01

    Purpose: Evaluate by CT the use of porous vitreous carbon (PVC) and silicon (S) implants as the replacement bone in the craniofacial skeleton of rats. Methods: 40 rats divided in: Group A (n=20) PVC submitted to the implant of a fragment in skull. After the euthanasia, the animals were divided into two subgroups: A I: 10 animals, studied in the 7th postoperative day (P.O) and AII: 10 animals, studied in the 28th P.O. In group B, S, 20 rats were submitted to S implant in the skull. All other steps were identical to group A, with designation of subgroups BI and BII. CT with beams in axial cuts of 1 mm thickness to obtain 3-D information It was used Hounsfield scale for evaluate the radio density of the implant. They were used non parametric tests to analyze the results. Results: The 7th PO boss remained in the two groups, but for 28th PO, observed reduction in the volume of the implant in Group A, not observed in group B. CT studies noticed different radio densities around all of S prostheses (pseudo capsule), that do not appeared in CPV implants. The S has remained unchanged in the CT, but the CPV has had a modification in its radio density (p≤0,05), in all implants. Conclusion: In CT evaluation the implants of CPV have greater deformation that the S, which makes them not suitable for replacement of membranous bone in the rat skull. (author)

  10. A new perspective in the estimation of postmortem interval (PMI) based on vitreous.

    Science.gov (United States)

    Muñoz, J I; Suárez-Peñaranda, J M; Otero, X L; Rodríguez-Calvo, M S; Costas, E; Miguéns, X; Concheiro, L

    2001-03-01

    The relation between the potassium concentration in the vitreous humor, [K+], and the postmortem interval has been studied by several authors. Many formulae are available and they are based on a correlation test and linear regression using the PMI as the independent variable and [K+] as the dependent variable. The estimation of the confidence interval is based on this formulation. However, in forensic work, it is necessary to use [K+] as the independent variable to estimate the PMI. Although all authors have obtained the PMI by direct use of these formulae, it is, nevertheless, an inexact approach, which leads to false estimations. What is required is to change the variables, obtaining a new equation in which [K+] is considered as the independent variable and the PMI as the dependent. The regression line obtained from our data is [K+] = 5.35 + 0.22 PMI, by changing the variables we get PMI = 2.58[K+] - 9.30. When only nonhospital deaths are considered, the results are considerably improved. In this case, we get [K+] = 5.60 + 0.17 PMI and, consequently, PMI = 3.92[K+] - 19.04.

  11. Electrochemical and AFM study of nickel nucleation mechanisms on vitreous carbon from ammonium sulfate solutions

    International Nuclear Information System (INIS)

    Grujicic, Darko; Pesic, Batric

    2006-01-01

    Reaction and nucleation mechanisms of nickel in ammoniacal solutions have been investigated as a function of nickel concentration, solution pH, deposition potential, temperature and conditioning potential. Electrochemical mechanisms of nickel reduction were found to be pH dependent, while their kinetics was concentration dependent. A surface film formed by anodic oxidation passivates nickel clusters preventing their further oxidation. Nickel nucleation on vitreous carbon, which proceeds according to the progressive nucleation model, shows a large degree of inhibition at both pH 6 and pH 9. Cluster sizes were larger when electrodeposition was carried out from solutions with higher nickel concentrations. The clusters were also larger at more negative deposition potentials and at higher solution pH. Cluster population density increased with the increasing solution temperature. Different activation energies for the nickel-aquo and nickel-ammino complexes calculated from Arrhenius diagram indicate that electroreduction of nickel-ammino complex is energetically more demanding. All electrochemical results were further verified by the atomic force microscopy investigations

  12. Microstructural observation of casein micelles in milk by cryo-electron microscopy of vitreous sections (CEMOVIS).

    Science.gov (United States)

    Kamigaki, Takamichi; Ito, Yosiko; Nishino, Yuri; Miyazawa, Atsuo

    2018-03-02

    Casein micelles are present in bovine milk as colloidal particles with diameters of 20-600 nm, which are complex macromolecular assemblies composed of four distinct types of casein and colloidal calcium phosphate (CCP). Multiple structural models of casein micelles have been proposed based on their biochemical or physical properties and observed using electron microscopy. However, the CCP distribution and crosslinking structure between CCP and casein remain unclear. Therefore, the internal structure of casein micelles in raw milk was observed using cryo-electron microscopy of vitreous sections (CEMOVIS) with high precision at high resolution. The results confirmed that the average casein micelle diameter was about 140 nm, and that the CCP diameter in casein micelles was about 2-3 nm, with an average diameter of 2.3 nm. The distribution of CCP in casein micelles was not uniform, with an average interval between CCPs of about 5.4 nm. Areas containing no black particles (attributed to CCP) were present, with an average size of about 19.1 nm. Considering previous reports, these areas possibly correspond to pores or cavities filled with water. Based on differences in the density of structures in casein micelles, we estimated that some of the casein aggregates were able to connect with CCP in a string.

  13. Managing the consequences of aggressive conservative treatment for refractory retinoblastoma with vitreous seeding

    Directory of Open Access Journals (Sweden)

    Aubrey Brink

    2014-08-01

    Full Text Available A 4 year-old girl with bilateral, non-familial retinoblastoma (RB was referred to our care after primary enucleation OS and active tumor OD refractory to multiple therapies (intravenous chemotherapy, laser/cryotherapy, and I-125 plaque radiotherapy. Vitreous seeding OD, initially controlled by several sessions of Ophthalmic Artery Infusion Chemotherapy (OAIC and periocular chemotherapy, recurred shortly thereafter. The patient underwent intravitreal (IVit Melphalan injections achieving tumor control despite the concurrent development of keratopathy, pupillary synechiae, cataract, and necrosis of the inferior fornix and the adjacent orbital fat, all secondary to the treatments administered. Repeated amniotic membrane implants and tarsorrhaphy were performed to alleviate the symptoms. Despite being tumor free for 6 months, a poor fundus view and treatment-related complications prompted us to consider enucleation, but parents declined. Following recent negative magnetic resonance imaging (MRI, her cataract was removed. She was then found to have tumor recurrence. Her eye was enucleated 12 months ago and she recovered well from the surgery. As ocular oncology embarks in eye-preserving treatments for retinoblastoma, it is important to address the cumulative effects and associated impact of such treatments and the possibility of failure.

  14. Er:YAB nanoparticles and vitreous thin films by the polymeric precursor method

    Energy Technology Data Exchange (ETDEWEB)

    Maia, Lauro J. Q., E-mail: lauro@if.sc.usp.b [Universidade de Sao Paulo, Grupo Crescimento de Cristais e Materiais Ceramicos, Departamento de Fisica e Ciencia dos Materiais, Instituto de Fisica de Sao Carlos (Brazil); Ibanez, Alain; Ortega, Luc [Laboratoire de Cristallographie CNRS associe a l' Universite Joseph Fourier et a l' INPG (France); Mastelaro, Valmor R.; Hernandes, Antonio C. [Universidade de Sao Paulo, Grupo Crescimento de Cristais e Materiais Ceramicos, Departamento de Fisica e Ciencia dos Materiais, Instituto de Fisica de Sao Carlos (Brazil)

    2008-12-15

    The synthesis of Y{sub 0.9}Er{sub 0.1}Al{sub 3}(BO{sub 3}){sub 4} crystalline powders and vitreous thin films were studied. Precursor solutions were obtained using a modified polymeric precursor method using d-sorbitol as complexant agent. The chemical reactions were described. Y{sub 0.9}Er{sub 0.1}Al{sub 3}(BO{sub 3}){sub 4} composition presents good thermal stability with regard to crystallization. The Y{sub 0.9}Er{sub 0.1}Al{sub 3}(BO{sub 3}){sub 4} crystallized phase can be obtained at 1,150 {sup o}C, in agreement with other authors. Crack- and porosity-free films were obtained with very small grain size and low RMS roughness. The films thickness revealed to be linearly dependent on precursor solution viscosity, being the value of 25 mPa s useful to prepare high-quality amorphous multi-layers (up to {approx} 800 nm) at 740 {sup o}C during 2 h onto silica substrates by spin coating with a gyrset technology.

  15. Smart platform for the time since death determination from vitreous humor cystine.

    Science.gov (United States)

    Ansari, Niha; Lodha, Anand; Menon, Shobhana K

    2016-12-15

    In this work, we report the smart application of AgNPs based sensors for determination of time since death (TSD) via recognition and quantification of vitreous humor (VH) cystine as well as provide the portability for on spot determination of TSD. The lower detection limit was found to be 7.0ng/ml with prominent selectivity. It was found that there is a linear correlation between the VH cystine concentration and TSD as the concentration of cystine increases up to 96h±3.9h. Further for the first time TSD determination is given a smart approach and it proves to have a great utility up to 24h±2.6h. The linear regression equation between TSD (the dependent variable), RGB intensity of cystine concentration till 24h (the independent variable) was found to be TSD=26.69+-0.05*x. The proposed method gives the smart detection, portability, rapidity, sensitivity, selectivity as well as cost effectiveness for determination of time since death. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Effect of neutron irradiation on the density of low-energy excitations in vitreous silica

    International Nuclear Information System (INIS)

    Smith, T.L.

    1979-01-01

    Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity were made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat C/sub ex/, the thermal conductivity kappa, and the anomalous temperature dependence of the ultrasound velocity Δv/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that kappa and Δv/v are determined by the same localized excitations responsible for C/sub ex/, but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. A consistent account for the measured C/sub ex/, kappa, and Δv/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model

  17. Simultaneous quantification of cocaine, amphetamines, opiates and cannabinoids in vitreous humor.

    Science.gov (United States)

    Peres, Mariana Dadalto; Pelição, Fabrício Souza; Caleffi, Bruno; De Martinis, Bruno Spinosa

    2014-01-01

    A GC-MS method for simultaneous analysis of cocaine (COC), amphetamines (AMPs), opiates, cannabinoids and their metabolites in vitreous humor (VH) was developed and fully validated. VH samples were extracted using solid phase extraction and injected into the GC-MS, using a selected ion monitoring mode. Linearity ranged from 10 to 1000 ng/mL; the exception was anhydroecgonine methyl ester (AEME), for which linearity ranged from 10 to 750 ng/mL. Inter-assay imprecision lay from 1.2 to 10.0%, intra-assay imprecision was samples taken from individuals whose blood had screened positive for drugs of abuse. All the individuals screened positive for COC in the blood (seven samples) also had positive results in VH; COC concentration ranged from 30.81 to 283.97 ng/mL (mean 186.98 ng/mL) and benzoylecgonine concentration ranged from 11.47 to 460.98 ng/mL (mean 133.91 ng/mL). It was also noticed that, in five cases, cocaethylene was detected. AEME was also quantified in one case. The use of AMP detected by blood analysis was confirmed in the VH of one individual (24.31 ng/mL). However, samples taken from three individuals whose blood tested positive for carboxy-tetrahydrocannabinol presented negative results. The results demonstrated that VH is a suitable alternative biological sample to determine COC, AMPs, opiates and their metabolites.

  18. On the Possibility of Calculating Entropy, Free Energy, and Enthalpy of Vitreous Substances

    Directory of Open Access Journals (Sweden)

    Sergei V. Nemilov

    2018-03-01

    Full Text Available A critical analysis for the arguments in support of, and against, the traditional approach to thermodynamics of vitreous state is provided. In this approach one presumes that there is a continuous variation of the entropy in the glass-liquid transition temperature range, or a “continuous entropy approach” towards 0 K which produces a positive value of the entropy at T → 0 K. I find that arguments given against this traditional approach use a different understanding of the thermodynamics of glass transition on cooling a liquid, because it suggests a discontinuity or “entropy loss approach” in the variation of entropy in the glass-liquid transition range. That is based on: (1 an unjustifiable use of the classical Boltzmann statistics for interpreting the value of entropy at absolute zero; (2 the rejection of thermodynamic analysis of systems with broken ergodicity, even though the possibility of analogous analysis was proposed already by Gibbs; (3 the possibility of a finite change in entropy of a system without absorption or release of heat; and, (4 describing the thermodynamic properties of glasses in the framework of functions, instead of functionals. The last one is necessary because for glasses the entropy and enthalpy are not functions of the state, but functionals, as defined by Gibbs’ in his classification.

  19. Removal of Cd+2 from aqueous solutions onto polypyrrole coated reticulated vitreous carbon eletrodes

    Directory of Open Access Journals (Sweden)

    Tramontina Jucelânia

    2001-01-01

    Full Text Available The development of simple methods for removal of heavy metals from aqueous samples is a relevant field of research. In this connection, the electrodeposition of the Cd+2 ion, one of the most toxic species for animals and human beings, was investigated in aerated pH 4.8 sulfuric-sulfate solutions. In potentiostatic conditions, the maximum rate of cadmium deposition at a neutral polypyrrole (PPy0 coated reticulated vitreous carbon (RVC working electrode occurs at -3.0 V vs. the saturated calomel reference electrode (SCE. Moreover, the conversion rate depends both on the applied potential and on the mass transport regime, and, for solutions containing 10 mg L-1 of Cd2+, the highest removal efficiency achieved is 84% after 90 min of electrolysis. The concentration decay of the Cd+2 ion in the solution was monitored by anodic stripping voltammetry (ASV at a hanging mercury drop electrode. Besides, metallic cadmium deposited onto the polypyrrole modified RVC electrode was evidenced by Scanning Electron Microscopy (SEM analysis using the backscattered electron image (BEI technique and by Energy Dispersive Spectrometry (EDS.

  20. Monitoring the Modifications of the Vitreous Humor Metabolite Profile after Death: An Animal Model

    Directory of Open Access Journals (Sweden)

    Maria Francesca Rosa

    2015-01-01

    Full Text Available We applied a metabolomic approach to monitor the modifications occurring in goat vitreous humor (VH metabolite composition at different times (0, 6, 12, 18, and 24 hours after death. The 1H-NMR analysis of the VH samples was performed for the simultaneous determination of several metabolites (i.e., the metabolite profile representative of the VH status at different times. Spectral data were analyzed by Principal Component Analysis (PCA and by Orthogonal Projection to Latent Structures (OPLS regression technique. PCA and OPLS suggested that different spectral regions were involved in time-related changes. The major time-related compositional changes, here detected, were the increase of lactate, hypoxanthine, alanine, total glutathione, choline/phosphocholine, creatine, and myo-inositol and the decrease of glucose and 3-hydroxybutyrate. We attempted a speculative interpretation of the biological mechanisms underlying these changes. These results show that multivariate statistical approach, based on 1H NMR metabolite profiling, is a powerful tool for detecting ongoing differences in VH composition and may be applied to investigate several physiological and pathological conditions.

  1. Evaluation of the vitreous matrices to include high-level radioactive wastes

    International Nuclear Information System (INIS)

    Varani, J.L.; Petraitis, E.J.; Pasquali, R.C.

    1987-01-01

    The Argentine Nuclear Programme considers a fuel cycle with Pu recycle. This will generate high-level liquid wastes, that should be safely eliminated. With this purpose, primary glasses utilizing three prototipe compositions were prepared. Simulated wastes oxides in the rate of about 10% were added to the vitreous matrices. The mixture was melted in ceramic melting pots in a muffle furnace at 1 100 deg C during 8 hours. Resistance leaching tests were made following an adaptation of the DIN 12 111 standard. Quantitative analysis of the leaching solutions were made to evaluate the solubility of the different elements. Glasses were observed with optical microscopy scanning before and after leaching. In the first, glasses, bubbles and crystalline-phase appear; in the second ones, puncture and embrittlement were detected. By means of differential thermoanalysis, endo and exothermal peaks were identified in glasses supporting gradual heating. X ray diffraction analysis were made in samples with and without wastes. The degree of crystallization of samples was evaluated by photographic and diffractometric techniques. Leaching studies showed the existance of a direct relation between leaching and glass alkaline content. (M.E.L.) [es

  2. Endocan concentrations in postmortem serum, vitreous humor and urine in victims of lethal hypothermia.

    Science.gov (United States)

    Descloux, Emilienne; Augsburger, Marc; Teresiński, Grzegorz; Hejna, Petr; Grouzmann, Eric; Scarpelli, Maria Pia; Hervet, Tania; Palmiere, Cristian

    2017-08-01

    Endocan is a soluble molecule secreted from vascular endothelial cells of various organs. Its exact function in humans remains to be elucidated, though it has been postulated that increased tissue expression or serum levels of this molecule may be an indicator of endothelial activation and neovascularization. In the realm of forensic pathology, studies pertaining to endothelial activation following exposure to cold exclusively focused on thrombomodulin, a transmembrane protein specific to endothelial cells. In the study herein described, endocan concentrations were determined in postmortem serum, urine and vitreous humor samples collected during autopsy in a series of cases that underwent medicolegal investigations. A total of 76 autopsy cases were selected and three study groups (hypothermia group, sepsis group and non-hypothermia/non-sepsis group) prospectively formed during the study period. The obtained results seem to indicate that exposure to cold and subsequent death is not distinguished by significant endothelial dysfunction causing enhanced endocan secretion. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  3. Cuba Through A New Lens

    Directory of Open Access Journals (Sweden)

    Jean Stubbs

    2008-12-01

    Full Text Available [First paragraph] The Origins of the Cuban Revolution Reconsidered. Samuel Farber. Chapel Hill: University of North Carolina Press, 2006. x + 212 pp. (Paper US$ 19.95 Cuba: A New History. Ric hard Gott . New Haven: Yale University Press, 2005. xii + 384 pp. (Paper US$ 17.00 Havana: The Making of Cuban Culture. Antoni Kapcia. Oxford: Berg Publishers, 2005. xx + 236 pp. (Paper US$ 24.95 Richard Gott, Antoni Kapcia, and Samuel Farber each approach Cuba through a new lens. Gott does so by providing a broad-sweep history of Cuba, which is epic in scope, attaches importance to social as much as political and economic history, and blends scholarship with flair. Kapcia homes in on Havana as the locus for Cuban culture, whereby cultural history becomes the trope for exploring not only the city but also Cuban national identity. Farber revisits his own and others’ interpretations of the origins of the Cuban Revolution.

  4. Radiation studies in Lens culinaris

    International Nuclear Information System (INIS)

    Sinha, S.S.N.

    1977-01-01

    Estimation of chromosomal aberrations in flowers of Lens culinaris according to their sequence of development in the plants at 4, 8 and 12 Kr in the M 1 generation, showed that the later formed flowers had smaller percentages of cells with aberrations than those developed earlier. It is suggested that this may be the result of competition between more damaged and less damaged cells during the development of the shoot. There is consequently a decrease of sterility in successive flowers. The numbers of karyotypes taking part in the formation of lower and uppermost flowers were estimated cytologically at 4, 8 and 12 Kr. It was found that more karyotypes were involved in the formation of the lower flowers than in the upper ones. It appeared that at lower doses larger numbers of karyotypes were taking part in the formation of the chimaera than at higher doses. (auth.)

  5. Microbial contamination of contact lens storage cases and domestic tap water of contact lens wearers.

    Science.gov (United States)

    Üstüntürk, Miray; Zeybek, Zuhal

    2012-11-01

    Contact lenses have been widely used as an alternative to spectacles both in developed and developing countries. However, under certain circumstances, adverse responses can occur during contact lens wear and several microorganisms--including bacteria, fungi, and free living amoebae--can cause several eye infections in wearers. Extended wear of contact lenses is the major risk factor of eye infections such as microbial keratitis, besides contaminated contact lens storage case, contaminated lens care solutions, and inaccurate contact lens handling. In this study, we collected contact lens storage case and domestic tap water samples from 50 asymptomatic contact lens wearers. We determined that total aerobic mesophilic bacteria were isolated in 45 (90 %), Gram negative rod bacteria were isolated in 20 (40 %), Pseudomonas spp. were isolated in 2 (4 %) and fungi were isolated in 18 (36 %) out of 50 contact lens storage cases. Free living amoebae were not detected in investigated contact lens storage cases. At the same time, out of 50, total aerobic mesophilic bacteria were isolated in 34 (68 %), fungi were isolated in 15 (30 %) and free living amoebae were isolated in 15 (30 %) domestic tap water samples. No Gram-negative rod bacteria and Pseudomonas spp. were detected in investigated water samples. Two contact lens case samples and two tap water samples were excluded from the analysis for Pseudomonas spp. for technical reasons. According to our findings, inadequate contact lens maintenance during lens wear may result in the contamination of contact lens storage cases. This situation can lead to severe eye infections in contact lens wearers over time.

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

    Science.gov (United States)

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

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Das Pranab

    2009-01-01

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

  8. Pax6- and Six3-mediated induction of lens cell fate in mouse and human ES cells.

    Directory of Open Access Journals (Sweden)

    Raymond M Anchan

    Full Text Available Embryonic stem (ES cells provide a potentially useful in vitro model for the study of in vivo tissue differentiation. We used mouse and human ES cells to investigate whether the lens regulatory genes Pax6 and Six3 could induce lens cell fate in vitro. To help assess the onset of lens differentiation, we derived a new mES cell line (Pax6-GFP mES that expresses a GFP reporter under the control of the Pax6 P0 promoter and lens ectoderm enhancer. Pax6 or Six3 expression vectors were introduced into mES or hES cells by transfection or lentiviral infection and the differentiating ES cells analyzed for lens marker expression. Transfection of mES cells with Pax6 or Six3 but not with other genes induced the expression of lens cell markers and up-regulated GFP reporter expression in Pax6-GFP mES cells by 3 days post-transfection. By 7 days post-transfection, mES cell cultures exhibited a>10-fold increase over controls in the number of colonies expressing γA-crystallin, a lens fiber cell differentiation marker. RT-PCR and immunostaining revealed induction of additional lens epithelial or fiber cell differentiation markers including Foxe3, Prox1, α- and β-crystallins, and Tdrd7. Moreover, γA-crystallin- or Prox1-expressing lentoid bodies formed by 30 days in culture. In hES cells, Pax6 or Six3 lentiviral vectors also induced lens marker expression. mES cells that express lens markers reside close to but are distinct from the Pax6 or Six3 transduced cells, suggesting that the latter induce nearby undifferentiated ES cells to adopt a lens fate by non-cell autonomous mechanisms. In sum, we describe a novel mES cell GFP reporter line that is useful for monitoring induction of lens fate, and demonstrate that Pax6 or Six3 is sufficient to induce ES cells to adopt a lens fate, potentially via non-cell autonomous mechanisms. These findings should facilitate investigations of lens development.

  9. Single-lens 3D digital image correlation system based on a bilateral telecentric lens and a bi-prism: validation and application.

    Science.gov (United States)

    Wu, Lifu; Zhu, Jianguo; Xie, Huimin

    2015-09-10

    By using the principle of stereovision, 3D digital image correlation (3D-DIC) can determine the 3D morphology and deformation of a target and has been widely used in experimental mechanics as a noncontact 3D measurement technique. To eliminate the limitations of the conventional 3D-DIC system, this study proposes a calibration-free single-lens 3D-DIC system based on a bilateral telecentric lens and a bi-prism. The performance of the proposed system is verified by tests of rigid-body translation along the out-of-plane direction. As a comparison, the same rigid-body translations are measured using a single-entocentric-lens 3D-DIC system. The results show that the measurement accuracy of the proposed system is higher than that of the entocentric-lens-based one. As an application, the proposed system is used to measure the thermal linear expansion of a ceramic plate at elevated temperatures. The reasonable measurement results verify its applicability in deformation measurements, even in high-temperature environments.

  10. Contact lens compliance among a group of young, university-based lens users in South India.

    Science.gov (United States)

    Noushad, Babu; Saoji, Yeshwant; Bhakat, Premjit; Thomas, Jyothi

    2012-01-01

    To investigate the rate of compliance with the soft contact lens care and maintenance procedures with a focus on contact lens wearing habits, cleaning and disinfecting procedures, and maintenance of lens care accessories in a group of young, university-based contact lens wearers Two hundred and sixteen young soft contact lens wearers with an age range of 18-22 years were selected conveniently from the student population of Manipal University, Manipal, India. After receiving informed consent from the participants, their level of compliance with contact lenses was assessed using a questionnaire. The mean (±SD) age of the participants was 21.86±2.35 years. Out of 216 subjects, only 34% of the lens users were identified to be compliant with the least level of compliance observed in the maintenance of lens care accessories. Conventional users showed significantly (p=0.001) better level of compliance compared to disposable wearers and so did the users who acquired their lenses from clinicians (p=0.001) compared to over-the-counter lens receipt. The gender (p=0.496) and years of experience in contact lens use (p=0.142) did not show any statistically significant difference in the level of compliance. This study demonstrated that non-compliance with lens care procedures among a group of young, university-based soft contact lens wearers is common. The results indicated that all subjects had some degree of non-compliance and the least level of compliance observed in the care of lens accessories.

  11. Tear film physiology and contact lens wear. II. Contact lens-tear film interaction.

    Science.gov (United States)

    Holly, F J

    1981-04-01

    The successful fitting of contact lenses requires the practitioner to take into account many properties of the specific lens type used but the practitioner must also understand patient factors including tear properties, use of appropriate solutions, procedures for lens cleaning, and efficiency of blinking. Selection of appropriate patients, selection of lens type, proper fitting, good maintenance, and training and monitoring of patients increase the probability of achieving success.

  12. Posterior chamber lens implantation with scleral fixation in children with traumatic cataract.

    Science.gov (United States)

    Caca, Ihsan; Sahin, Alparslan; Ari, Seyhmus; Alakus, Fuat

    2011-01-01

    To evaluate the outcomes of posterior chamber lens implantation with scleral fixation (SF-PCIOL) in children with traumatic cataract. Twenty-four eyes of 24 cases were included. All patients had corneal or corneoscleral lacerations that were primarily repaired. Traumatic cataract subsequently developed and SF-PCIOL was performed due to insufficient posterior capsule support. The average age of the patients was 5.8 years (range: 4 to 10 years). All cases had SF-PCIOL implanted via internal route using triangular double scleral flaps made of 9-0 polypropylene after a complete anterior vitrectomy. Average follow-up was 14.6 ± 4.3 months (range: 11 to 18 months). Visual acuity was increased at the last visit in 23 (96%) patients. Common postoperative complications were fibrinous reaction in 6 (25%) patients, transient intraocular pressure increase in 4 (17%) patients, membrane formation requiring removal in 1 (4%) patient, transient intraocular hemorrhage as vitreous hemorrhage in 1 (4%) patient, and retinal detachment in 1 (4%) patient after the postoperative second month. SF-PCIOL is an effective and reliable method in patients with pediatric traumatic cataract who had insufficient posterior capsule support. Copyright 2011, SLACK Incorporated.

  13. Placement of a crystalline lens and intraocular lens: Retinal image quality.

    Science.gov (United States)

    Siedlecki, Damian; Nowak, Jerzy; Zajac, Marek

    2006-01-01

    The influence of changes of both crystalline lens and intraocular lens (IOL) misalignment on the retinal image quality was investigated. The optical model of the eye used in investigations was the Liou-Brennan model, which is commonly considered as one of the most anatomically accurate. The original crystalline lens from this model was replaced with an IOL, made of rigid polymethylmethacrylate, in a way that recommend obligatory procedures. The modifications that were made both for crystalline lens and IOL were the longitudinal, the transversal, and the angular displacement.

  14. Restoring lens capsule integrity enhances lens regeneration in New Zealand albino rabbits and cats.

    Science.gov (United States)

    Gwon, A; Gruber, L J; Mantras, C

    1993-11-01

    In studies conducted by numerous investigators for 150 years, lenses regenerated following endocapsular lens extraction in New Zealand albino rabbits have been irregular in shape, appearing primarily doughnut-shaped as a result of lack of lens growth at the site of the anterior capsulotomy and its adhesion to the posterior capsule. In the present study, we restored the lens capsule integrity by inserting a collagen patch at the time of surgery to seal the anterior capsulotomy and to improve the shape and structure of the regenerated lenses. We then filled the capsule bag with air to prevent adhesions between the anterior and posterior capsule and maintain capsule tautness and shape. Lens regeneration was first noted as early as one to two weeks. Regenerated lens filled approximately 50% of the capsule bag at two weeks and 100% by five weeks. Subsequent growth was in the anterior-posterior direction and measured by A-scan biometry. Lens thickness increased by 0.3 mm per month. The regenerated lenses were spherical with normal cortical structure and a nuclear opacity. In conclusion, restoration of lens capsular integrity with a collagen patch following endocapsular lens extraction enhanced the shape, structure, and growth rate of the regenerated lenses. In addition, lens regeneration was shown to occur in two cats.

  15. Development of Fresnel lens for improvement of rear visibility; Shikai kojo Fresnel lens no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, K.; Sanada, C.; Tsukino, M. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    Fresnel lenses have been widely used to increase the visual field around vehicles for drivers. However, internal reflection in these lenses has been an obstacle in producing dear images. This internal glow is generated by incident light from an unexpected direction reflecting on the non-lens surface or radiating from the non-lens surface of the Fresnel lens. The cause of internal glow has been made dear combining louver film with the lens. The newly developed technology removes obstacles in producing dear images by reducing internal glow. 7 figs.

  16. The usefulness of point-of-care (POC) tests in screening elevated glucose and ketone body levels postmortem

    OpenAIRE

    Walta, Anna-Mari; Keltanen, Terhi; Lindroos, Katarina; Sajantila, Antti

    2016-01-01

    The aim was to evaluate the performance of point-of-care (POC) tests in detecting glucose and ketone bodies in postmortem (PM) samples and to assess the usefulness of POC tests in sample screening for more precise analyses. Glucose and ketone body, beta-hydroxybutyrate (BHB), were measured from vitreous humor (VH) in 52 autopsy cases with a POC blood glucose monitoring device (BGMD). In addition glucose and ketone bodies, acetone (Ac) and acetoacetate (AcAc), were measured from urine samples ...

  17. Night Vision Goggles Objectives Lens Focusing Methodology

    National Research Council Canada - National Science Library

    Pinkus, Alan; Task, H. L

    2000-01-01

    ...: interpupillary distance, tilt, eye relief, height, eyepiece and objective lens focus. Currently, aircrew use a Hoffman 20/20 test unit to pre-focus their NVG objective lenses at optical infinity before boarding their aircraft...

  18. Role of Aquaporin 0 in lens biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  19. Contractual considerations in contact lens practice.

    Science.gov (United States)

    Classé, J G

    1986-03-01

    The use of forms in contact lens practice can save time, promote patient education, and reduce the opportunity for legal or economic disputes. The most commonly employed forms are those for contact lens fitting agreements, instructions for care and maintenance of lenses, prepaid service agreements, clinical investigations of investigatory lenses or solutions, and for extended wear patients. Sample forms are utilized for purposes of illustration.

  20. Evolution and the Calcite Eye Lens

    OpenAIRE

    Williams, Vernon L.

    2013-01-01

    Calcite is a uniaxial, birefringent crystal, which in its optically transparent form, has been used for animal eye lenses, the trilobite being one such animal. Because of the calcite birefringence there is a difficulty in using calcite as a lens. When the propagation direction of incoming light is not exactly on the c-axis, the mages blur. In this paper, calcite blurring is evaluated, and the non-blurring by a crystallin eye lens is compared to a calcite one.

  1. Acute lens-induced glaucomas: A review

    Directory of Open Access Journals (Sweden)

    Syed Shoeb Ahmad

    2017-02-01

    Full Text Available Lens-induced factors are important and common mechanisms causing acute elevation of intraocular pressure. While in most cases, the diagnosis and management are straight-forward, in others it is difficult and can lead to improper procedures, complications and poor visual outcomes. This review was done with the aim of studying the various types of lens-induced glaucomas, classifying them in an easy way to understand manner, their clinical features, current management and future possibilities.

  2. Does the level of available oxygen impact comfort in contact lens wear?: A review of the literature.

    Science.gov (United States)

    Dillehay, Sally M

    2007-05-01

    Wear of low-Dk/t lenses has long been associated with signs and symptoms indicative of hypoxia and with patient symptoms of dryness and discomfort. Although patient discomfort during soft contact lens wear has been generally attributed to lens dehydration, research studies aimed at verifying that connection have been unsuccessful. With the advent of high-Dk/t silicone hydrogel lenses, not only have improvements in clinical signs of hypoxia been documented, but improvements in patient symptoms of dryness and discomfort also have been documented. This literature review was undertaken to examine historic and current literature to determine whether the level of available oxygen is associated with patient symptoms of dryness and discomfort. Literature was reviewed related to soft contact lens dehydration, corneal hypoxia, patient symptoms of dryness and discomfort, and current clinical studies of silicone hydrogel lens wear. Through the years, the body of knowledge has grown supporting a connection between decreased levels of available oxygen to the cornea caused by low-Dk/t contact lens wear and negative impacts on the signs of corneal health and patient symptoms. Available published literature suggests that many of these changes in patient signs and symptoms seen with low-Dk/t lens wear may be related to an inflammatory response. Clinical studies of high-Dk/t silicone hydrogel lenses further support a significant connection between the level of available oxygen during contact lens wear and improved patient symptoms of comfort, including dryness.

  3. Microbial profile of the vitreous aspirates in culture proven exogenous endophthalmitis: A 10-year retrospective study

    Directory of Open Access Journals (Sweden)

    H Bhattacharjee

    2016-01-01

    Full Text Available Purpose: To describe the microbiological profile and clinical outcome in the eyes with culture-proven exogenous endophthalmitis. Methods: A retrospective analysis of 495 eyes diagnosed as exogenous endophthalmitis was performed over a period of 10 years. In all, aseptically collected aqueous and vitreous aspirates were cultured for bacteria and fungus using standard microbiological techniques. Gram-stain and KOH preparation of the specimens were also performed. The antibiotic susceptibility testing for bacterial isolates was performed by Kirby-Bauer disk diffusion method. The treatment was modified according to the antibiotic sensitivity profile. The final clinical ocular condition was divided into improved, stable or deteriorated. Results: Of 148 culture-proven endophthalmitis eyes, 137 (92.57% were referred from elsewhere, and 11 (7.43% belonged to our institute. Aetiologically, 76 (51.35% eyes were post-cataract surgery, 61 (41.22% were post-traumatic, 5 (3.38% eyes post-intravitreal anti-vascular endothelial growth factor injection, 5 associated with corneal diseases and 1 bleb-related endophthalmitis. In 31 (20.95% eyes, primary intravitreal antibiotics were given outside. The cultures revealed monomicrobial growth in 92.57% (n = 137 and polymicrobial growth in 7.43% (n = 11. Among the bacteria (n = 121, 81.76%, Pseudomonas species dominated overall (n = 32, 27.11% and post-operative (n = 26, 38.23% endophthalmitis group. Staphylococcus epidermidis (n = 14, 28% was prominent in post-traumatic endophthalmitis group. Ninety-two percent (n = 108 isolates of bacteria were sensitive to vancomycin. In 78 (52.7% eyes, the clinical ocular condition improved or remained stable while deteriorated in 51 (34.46%. Conclusion: A bacterial predominance was observed among causative organisms of exogenous endophthalmitis with Pseudomonas species being the most common. The appropriate surgical intervention improved or stabilised the visual acuity in nearly

  4. Prototropic studies in vitreous and in solid phases: Pyranine and 2-naphthol excited state proton transfer

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Fátima Aparecida das Chagas [Departamento de Química Fundamental, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, SP (Brazil); Rezende, Eduardo Triboni [Universidade Nove de Julho, São Paulo, SP (Brazil); Filho, Décio Briotto [Departamento de Bioquímica Instituto de Química, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, SP (Brazil); Brito Rezende, Daisy de [Departamento de Química Fundamental, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, SP (Brazil); Cuccovia, Iolanda Midea [Departamento de Bioquímica Instituto de Química, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, SP (Brazil); Gome, Ligia Ferreira [Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, SP (Brazil); Silva, Mauro Francisco Pinheiro da [Departamento de Química Fundamental, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, SP (Brazil); and others

    2014-02-15

    Excited state proton transfer processes in vitreous glasses and in solid mixtures are investigated by steady state fluorimetry and laser flash photolysis kinetic studies with the photoacids pyranine and 2-naphthol. Glasses were derived from TEOS by the sol–gel condensation process and hydrated solid mixtures from NaCl or KH{sub 2}PO{sub 4}/K{sub 2}HPO{sub 4} crystals. The extent of the water content necessary for the reaction is determined. Shrinkage of TEOS derived monoliths from water loss leads to an increase in proton transfer extent due to the increase in local concentrations of accepting and donor buffer species, but the concomitant increase in the ionic strength actuates in an opposite direction. Furthermore, water losses by aging of air-exposed gel goes to a critical 20% weight fraction, beyond it proton transfer reactions are hindered. Similar studies with solid NaCl or solid phosphate buffer mixtures demonstrated the same critical water level indicating that free water molecules are crucial for the proton to escape from the original cage where the geminate ion pair [–||RO{sup −⁎}H{sup +}||–] is formed and can undergo coupled proton transfer reactions. -- Highlights: • Pyranine and 2-naphthol excited state proton transfer in SiO{sub 2} gel, solid phosphate buffer and NaCl. • Sol–gel formation leads to contraction and concentration of donor and accepting species. • 20% weight fraction water is required for the ESPT to go forward.

  5. Electron paramagnetic resonance of Al E1/sup prime/ centers in vitreous silica

    International Nuclear Information System (INIS)

    Brower, K.L.

    1979-01-01

    A new series of 27 Al hyperfine spectra have been discovered by EPR studies in irradiated type-I and -II vitreous silica. Our analysis of these spectra indicate that under ionizing irradiation at low temperatures (T + , Li + , or H/sub n//sup ts+/. With the aid of high-temperature electrolysis, specific spectra are associated with specific compensators. In one spectrum a superhyperfine interaction with an isotope having I=3/2 and attributed to 23 Na is observed. We observe that the role of charge compensators with respect to the charge (magnetic) state of these Al defects in SiO 2 gives a consistent indication of the aluminum-oxygen coordination. We also demonstrate a correlation between the strength of the 27 Al contact hyperfine interaction, the presence of charge compensators, and the thermal stability of the trapped electron. An analysis of the 27 Al and 29 Si hyperfine interactions arising from paramagnetic AlO/sub 3/2//sup ts-/ and SiO/sub 3/2/ (E 1 /sup prime/) centers indicate that these two centers are isoelectronic. Each of the four 27 Al hyperfine spectra are analyzed in terms of coaxial Zeeman and hyperfine interactions which include broadening effects due to variations in bond angles and lengths. Ideas about how Al and Si E 1 /sup prime/ centers might be incorporated in the v-SiO/sub 4/2/ network are also presented. In particular, a model for an extrinsic Si E 1 /sup prime/ center is proposed which may explain various effects observed with EPR in different kinds of v-SiO 2 60 CO γ irradiated with fluences 7 R

  6. Cost-Utility of Evaluation for Posterior Vitreous Detachment and Prophylaxis of Retinal Detachment.

    Science.gov (United States)

    Yannuzzi, Nicolas A; Chang, Jonathan S; Brown, Gary C; Smiddy, William E

    2018-01-01

    To evaluate the costs and cost-utility of examination for posterior vitreous detachment (PVD) and treatment of associated pathology, and of managing various other peripheral retinal disorders to prevent retinal detachment (RD). A decision analysis model of cost-utility. There were no participants. Published retrospective data on the natural course of PVD, retinal tears, and lattice degeneration were used to quantitate the visual benefits of examination and treatment. Center for Medicare and Medicaid Services data were used to calculate associated modeled costs in a hospital/facility-based and nonfacility/ambulatory surgical center (ASC)-based setting. Published standards of utility for a given level of visual acuity were used to derive costs and quality-adjusted life years (QALYs). Cost of evaluation and treatment, utility of defined health states, QALY, and cost per QALY. The modeled cost of evaluation of a patient with PVD and treatment of associated pathology in the facility/hospital (nonfacility/ASC)-based setting was $65 to $190 ($25-$71) depending on whether a single or 2-examination protocol was used. The cost per QALY saved was $255 to $638/QALY ($100-$239/QALY). Treatment of a symptomatic horseshoe tear resulted in a net cost savings of $1749 ($1314) and improved utility, whereas treatment of an asymptomatic horseshoe tear resulted in $2981/QALY ($1436/QALY). Treatment of asymptomatic lattice degeneration in an eye in which the fellow eye had a history of RD resulted in $4414/QALY ($2187/QALY). Evaluation and management of incident acute PVD (and symptomatic horseshoe tears) offer a low cost and a favorable cost-utility (low $/QALY) as a result of the minimization of the cost and morbidity associated with the development of RD, thus justifying current practice standards. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  7. [The incidence of retinal tears in patients with posterior vitreous detachment].

    Science.gov (United States)

    Karaman, Ksenija; Gverović-Antunica, Antonela; Bućan, Kajo; Znaor, Ljubo; Bulović, Dijana; Skelin, Sinia

    2006-01-01

    Posterior vitreous detachment (PVD) is a common finding in older patients, characterized by detachment of the posterior hyaloid membrane (PHM) from the retinal surface. The detachment of PHM normally occurs without complications, however, one has to be aware that retinal tear is its most common complication. The aim of the study was to determine the incidence of retinal tears in eyes with PVD. A series of 40 patients (70 eyes) with PVD were included in this retrospective study. Eyes with a history of ocular trauma, surgery or intraocular inflammation were excluded. Patient charts were reviewed to collect the following information: age, sex, profession, type and duration of symptoms, best corrected visual acuity, refractive status, prior ocular disease, coincidental retinal pathology-lattice degeneration, number, type and location of retinal tears and treatment. Statistical analysis was done with the SPSS 11.0.3 software (SPSS Inc., USA). Besides descriptive statistics, Student's t-test and chi2-test were used. Among all study eyes with PVD, 34 (48.6%) were myopic, 24 (34.3%) hypermetropic and 12 (17.1%) emetropic; statistical analysis showed a significant difference (chi2 = 10.40, df=2, p lattice malignant degeneration of peripheral retinal was diagnosed. Thorough examination of the fundus periphery revealed 16 (22.8%) eyes with PVD were found to have retinal tears, 11 (15.7%) had only one retinal tear and 5 (7.1%) two retinal tears. All retinal tears were treated with argon laser photocoagulation. Superotemporal eye quadrant was the most common localization of retinal tears (56.25%). These results indicate that thorough fundus periphery examination should be done in all patients with PVD because it can cause rather rarely though retinal tears that represent a potentially sight threatening condition.

  8. Raman spectroscopy of femtosecond multipulse irradiation of vitreous silica: Experiment and simulation

    Science.gov (United States)

    Shcheblanov, N. S.; Povarnitsyn, M. E.; Mishchik, K. N.; Tanguy, A.

    2018-02-01

    We report an experimental and numerical study of femtosecond multipulse laser-induced densification in vitreous silica (v -SiO2 ) and its signature in Raman spectra. We compare the experimental findings to the recently developed molecular dynamics (MD) approach accounting for bond breaking due to laser irradiation, together with a dynamical matrix approach and bond polarizability model based on first-principles calculations for the estimation of Raman spectra. We observe two stages of the laser-induced densification and Raman spectrum evolution: growth during several hundreds of pulses followed by further saturation. At the medium range, the network connectivity change in v -SiO2 is expressed in reduction of the major ring fractions leading to more compacted structure. With the help of the Sen and Thorpe model, we also study the short-range order transformation and derive the interbonding Si-O-Si angle change from the Raman measurements. Experimental findings are in excellent agreement with our MD simulations and hence support a bond-breaking mechanism of laser-induced densification. Thus, our modeling explains well the laser-induced changes both in the short-range order caused by the appearance of Si coordination defects and medium-range order connected to evolution of the ring distribution. Finally, our findings disclose similarities between sheared, permanently densified, and laser-induced glass and suggest interesting future experiments in order to clarify the impact of the thermomechanical history on glasses under shear, cold and hot compression, and laser-induced densification.

  9. Acoustic lens for capacitive micromachined ultrasonic transducers

    Science.gov (United States)

    Chang, Chienliu; Firouzi, Kamyar; Park, Kwan Kyu; Sarioglu, Ali Fatih; Nikoozadeh, Amin; Yoon, Hyo-Seon; Vaithilingam, Srikant; Carver, Thomas; Khuri-Yakub, Butrus T.

    2014-08-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing.

  10. Acoustic lens for capacitive micromachined ultrasonic transducers

    International Nuclear Information System (INIS)

    Chang, Chienliu; Firouzi, Kamyar; Sarioglu, Ali Fatih; Nikoozadeh, Amin; Yoon, Hyo-Seon; Vaithilingam, Srikant; Carver, Thomas; Khuri-Yakub, Butrus T; Kyu Park, Kwan

    2014-01-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing. (paper)

  11. LENS: Science Scope and Development Stages

    Science.gov (United States)

    Vogelaar, R. Bruce

    2013-04-01

    The Low-Energy Neutrino Spectroscopy (LENS) experiment will resolve the solar metallicity question via measurement of the CNO neutrino flux, as well as test the predicted equivalence of solar luminosity as measured by photon versus neutrinos. The LENS detector uses charged-current interaction of neutrinos on Indium-115 (loaded in a scintillator, InLS) to reveal the complete solar neutrino spectrum. LENS's optically segmented 3D lattice geometry achieves precise time and spatial resolution and unprecedented background rejection and sensitivity for low-energy neutrino events. This first-of-a-kind lattice design is also suited for a range of other applications where high segmentation and large light collection are required (eg: sterile neutrinos with sources, double beta decay, and surface detection of reactor neutrinos). The physics scope, detector design, and logic driving the microLENS and miniLENS prototyping stages will be presented. The collaboration is actively running programs; building, operating, developing, and simulating these prototypes using the Kimballton Underground Research Facility (KURF). New members are welcome to the LENS Collaboration, and interested parties should contact R. Bruce Vogelaar.

  12. Tethered capsule OCT endomicroscopy for upper gastrointestinal tract imaging by using ball lens probe (Conference Presentation)

    Science.gov (United States)

    Dong, Jing; Gora, Michalina J.; Reddy, Rohith; Trasischker, Wolfgang; Poupart, Oriane; Lu, Weina; Carruth, Robert W.; Grant, Catriona N.; Soomro, Amna R.; Tiernan, Aubrey R.; Rosenberg, Mireille; Nishioka, Norman S.; Tearney, Guillermo J.

    2016-03-01

    While endoscopy is the most commonly used modality for diagnosing upper GI tract disease, this procedure usually requires patient sedation that increases cost and mandates its operation in specialized settings. In addition, endoscopy only visualizes tissue superfically at the macroscopic scale, which is problematic for many diseases that manifest below the surface at a microscopic scale. Our lab has previously developed technology termed tethered capsule OCT endomicroscopy (TCE) to overcome these diagnostic limitations of endoscopy. The TCE device is a swallowable capsule that contains optomechanical components that circumferentially scan the OCT beam inside the body as the pill traverses the organ via peristalsis. While we have successfully imaged ~100 patients with the TCE device, the optics of our current device have many elements and are complex, comprising a glass ferrule, optical fiber, glass spacer, GRIN lens and prism. As we scale up manufacturing of this device for clinical translation, we must decrease the cost and improve the manufacturability of the capsule's optical configuration. In this abstract, we report on the design and development of simplificed TCE optics that replace the GRIN lens-based configuration with an angle-polished ball lens design. The new optics include a single mode optical fiber, a glass spacer and an angle polished ball lens, that are all fusion spliced together. The ball lens capsule has resolutions that are comparable with those of our previous GRIN lens configuration (30µm (lateral) × 7 µm (axial)). Results in human subjects show that OCT-based TCE using the ball lens not only provides rapid, high quality microstructural images of upper GI tract, but also makes it possible to implement this technology inexpensively and on a larger scale.

  13. Experimental observation of lens damage after low doses of γ-ray irradiation to rabbit eyes

    International Nuclear Information System (INIS)

    Tang Xicheng; Hu Chunzhi; Wang Huijun; Zeng Aiping

    2000-01-01

    Objective: To investigate and evaluate low dose γ-ray radiation induced lens damage. Methods: Both eyes of each rabbit were exposed to a single dose of 25 or 50 cGy γ-rays in two groups, respectively. Samples were examined by transmission electron microscopy (TEM) and slit lamp microscopy (SLM)after irradiation. Results: Three days after 25 and 50 cGy irradiation,the epithelial cells of lens equator al region showed marked swelling and many vacuoles formed in intercellular space and cytoplasm,and accompanied by increased multi-lamellar bodies. Five months after irradiation, SLM of both groups showed that the posterior sub-capsule cortex exhibited clusters of vacuoles; 11 months after 50 cGy irradiation,the posterior sub-capsule and deep cortex manifested marked cloudy opacities. Conclusion: Low doses of γ-ray (25 and 50 cGy) irradiation can markedly damage lens of rabbits

  14. New trends in intraocular lens imaging

    Science.gov (United States)

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

    2011-08-01

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

  15. Sharing of secondary electrons by in-lens and out-lens detector in low-voltage scanning electron microscope equipped with immersion lens.

    Science.gov (United States)

    Kumagai, Kazuhiro; Sekiguchi, Takashi

    2009-03-01

    To understand secondary electron (SE) image formation with in-lens and out-lens detector in low-voltage scanning electron microscopy (LV-SEM), we have evaluated SE signals of an in-lens and an out-lens detector in LV-SEM. From the energy distribution spectra of SEs with various boosting voltages of the immersion lens system, we revealed that the electrostatic field of the immersion lens mainly collects electrons with energy lower than 40eV, acting as a low-pass filter. This effect is also observed as a contrast change in LV-SEM images taken by in-lens and out-lens detectors.

  16. [Study on the relationship between PMI and the concentration of magnesium and iron in the vitreous humor of rabbit after death].

    Science.gov (United States)

    Xu, Xiao-ming; Gong, Zhi-qiang; Sun, Yue-gang

    2002-05-01

    To seek a exact method of estimating postmortem interval (PMI). This study detected the concentration of magnesium (Mg) and iron (Fe) in vitreous humor of rabbit at 96 h after death and explored the relationship between their concentration and PMI using a method ICP-MS. The concentra-tion of Mg in vitreous humor of rabbit at 48 h after death and Fe in vitreous humor of rabbit at 6-48 h after death were related to PMI significantly. The formulae of the relationship between PMI and Mg concentrations is y = 0.0738x2 + 0.6997x + 11.45 (within 48 h, R2 = 0.9119). The formulae of the relationship between PMI and Fe concentrations is y = 0.0411x2 - 0.3148x + 1.4113 (within 6-48 h, R2 = 0.9594). The concentration of Mg in vitreous humor of rabbit at 48 h after death and Fe in vitreous humor of rabbit at 6-48 h after death may be as reference indicator to estimate PMI.

  17. Postmortem vitreous chemistry--an evaluation of sodium, potassium and chloride levels in estimation of time since death (during the first 36 h after death).

    Science.gov (United States)

    Chandrakanth, H V; Kanchan, Tanuj; Balaraj, B M; Virupaksha, H S; Chandrashekar, T N

    2013-05-01

    Estimation of time since death is a paramount medico-legal issue in any postmortem examination. The present study is intended to study the correlation between postmortem interval and vitreous humor chemistry for sodium, potassium, and chlorides. The study is aimed to find male-female differences and differences between right and left eyes in vitreous chemistry. The vitreous humor samples were collected in 114 autopsies conducted in the study center and analyzed biochemically. All the cases where exact time of death was known and where the time since death ranged between 0 and 36 h were included in the study. Data obtained was analyzed statistically using spss version 11.0. The present research did not find a significant correlation between vitreous chemistry and postmortem interval. The differences in vitreous sodium, potassium, chloride levels and the sodium potassium ratio among males and females and between right and left eyes were not found to be statistically significant. Copyright © 2012 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  18. Determination of the dose in eyes lens by TLD, in PET/CT by technicians in PET/CT service

    International Nuclear Information System (INIS)

    Marino, Emiliano A.

    2013-01-01

    This work was supported, on the one hand, in a part of the project ORAMED which consisted of a design of a TLD dosimeter for measurements of Hp (3) in areas close to the lens, for interventional radiology physicians. On the other hand, Berhens work proposes using calibrated TLDs Hp (0.07) and Hp (10) to estimate Hp (3) crystal. This resulted in dosimeters calibrated using Hp (10) slab, and mount them on glasses, to estimate the dose to the lens of the technical staff of the Service PET / CT. The value obtained 29mSv/year of Lens Dose Equivalent exceeds the recommended limit. We also demonstrate that, under the current working conditions, the values of Hp (3) reported from whole body dosimeter does not represent faithfully the lens dose

  19. Dose conversion coefficients for photon exposure of the human eye lens

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G

    2011-01-01

    In recent years, several papers dealing with the eye lens dose have been published, because epidemiological studies implied that the induction of cataracts occurs even at eye lens doses of less than 500 mGy. Different questions were addressed: Which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens? Is a new definition of the dose quantity H p (3) based on a cylinder phantom to represent the human head necessary? Are current conversion coefficients from fluence to equivalent dose to the lens sufficiently accurate? To investigate the latter question, a realistic model of the eye including the inner structure of the lens was developed. Using this eye model, conversion coefficients for electrons have already been presented. In this paper, the same eye model-with the addition of the whole body-was used to calculate conversion coefficients from fluence (and air kerma) to equivalent dose to the lens for photon radiation from 5 keV to 10 MeV. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are similar between 40 keV and 1 MeV and lower by up to a factor of 5 and 7 for photon energies at about 10 keV and 10 MeV, respectively. Above 1 MeV, the new values (calculated without kerma approximation) should be applied in pure photon radiation fields, while the values adopted by the ICRP in 1996 (calculated with kerma approximation) should be applied in case a significant contribution from secondary electrons originating outside the body is present.

  20. Comparison of the Results of Secondary Anterior Chamber and Secondary Scleral-Fixated Intraocular Lens Implantation in Complicated Phacoemulsification Cases

    Directory of Open Access Journals (Sweden)

    Nimet Yeşim Erçalık

    2014-03-01

    Full Text Available Objectives: To compare the visual prognosis and postoperative complication rates of secondary anterior chamber (AC IOL and scleralfixated (SF intraocular lenses (IOL after complicated phacoemulsification surgery. Materials and Methods: Thirty eyes of thirty patients were reviewed for this retrospective study. The patients with secondary AC IOL implantation formed group 1 (n=15, and the patients with secondary SF IOL implantation formed group 2 (n=15. Best-corrected visual acuity (BCVA with Snellen chart, biomicroscopic examination, intraocular pressure (IOP measurement with applanation tonometer, gonioscopy performed by Goldmann’s 3-mirror contact lens, and fundus examination were performed preoperatively in all patients. Results: There was no statistically significant difference in postoperative BCVA (p=0.492 and postoperative success (BCVA not changed or better postoperatively between the 2 groups (p=0.598. Postoperative success rate was 80% in group 1 and 93.7% in Group 2. The postoperative cylindrical power of the eyes did not differ significantly between the groups (p=0.220. The postoperative complications in group 1 were as follows: transient corneal edema in 5 eyes, transient IOP elevation in 2 eyes, postoperative fibrinous reaction in the anterior chamber in one eye, late-onset secondary glaucoma in one eye, hyphema in one eye, cystoid macular edema in one eye, vitreous prolapse into the anterior chamber in one eye, and IOL malposition in one eye. The postoperative complications in group 2 were as follows: transient corneal edema in 3 eyes, vitreous prolapse into the anterior chamber in 2 eyes, IOL malposition in 2 eyes, transient IOP elevation in one eye, and retinal detachment in one eye. Conclusion: In this study, both IOL types were observed to be preferable in cases without adequate capsular support following complicated cataract surgery. However, further studies with large numbers of patients are needed to define the best choice

  1. A classification system of intraocular lens dislocation sites under operating microscopy, and the surgical techniques and outcomes of exchange surgery.

    Science.gov (United States)

    Hayashi, Ken; Ogawa, Soichiro; Manabe, Shin-Ichi; Hirata, Akira; Yoshimura, Koichi

    2016-03-01

    The aim of this study was to examine the recent status of intraocular lens (IOL) dislocation according to a classification system based on vertical dislocation position, as well as the surgical techniques and outcomes of IOL exchange surgery. The medical records of 230 eyes from 214 consecutive patients who experienced IOL dislocation and underwent exchange surgery between 2006 and 2014 were reviewed. Vertical dislocation sites observed preoperatively under operating microscopy were examined, along with the surgical techniques and outcomes of IOL exchange. Dislocation sites included (1) the anterior chamber (12.2 %), (2) pseudophakodonesis (19.1 %), (3) the anterior vitreous cavity (47.4 %), (4) trap door-like dislocation (dangling in the peripheral vitreous cavity; 16.1 %), and (5) the retinal surface (5.2 %). The IOL retained in the anterior segment was moved onto the iris by pulling it up through the limbal side ports with an anterior vitrectomy (67.8 %), or by pushing it up from the pars plana with an anterior vitrectomy (26.5 %), while the IOL dropped on the retina was lifting it up from the retina after pars plana vitrectomy (5.7 %). Mean uncorrected and distance-corrected visual acuity significantly improved postoperatively (p system, approximately 95 % of dislocated IOLs were retained in the anterior segment, and these IOLs were exchanged using an anterior approach through limbal incisions with an anterior vitrectomy. Visual acuity improved significantly, and serious complications were uncommon, probably because the IOL exchange techniques were standardized and simplified without pars plana vitrectomy.

  2. Effects of scaffold surface morphology on cell adhesion and survival rate in vitreous cryopreservation of tenocyte-scaffold constructs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhi [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China); Department of Bone and Joint Surgery, The affiliated hospital of Luzhou Medical College, Luzhou 646000 (China); Qing, Quan [Sichuan College of Traditional Chinese Medicine, Mianyang 621000 (China); Regenerative Medicine Research Center, West China Hospital of Sichuan University, Chengdu 610041 (China); Chen, Xi; Liu, Cheng-Jun; Luo, Jing-Cong [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China); Hu, Jin-Lian [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China); Qin, Ting-Wu, E-mail: tingwuqin@hotmail.com [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China)

    2016-12-01

    Highlights: • The shapes of tenocytes varied when seeded on different surface of scaffolds. • Tenocytes were flat on smooth surface and spindle on micro-grooved surface. • Tenocytes were ellipse or spindle on porous surface. • Tenocytes got varying adhesion shape and elongation index on varying surfaces. • The tenocyte survival on porous surface was superior to the other two groups. - Abstract: The purpose of this study was to investigate the effects of scaffold surface morphology on cell adhesion and survival rate in vitreous cryopreservation of tenocyte-scaffold constructs. Tenocytes were obtained from tail tendons of rats. Polydimethylsiloxane (PDMS) was used to fabricate three types of scaffolds with varying surface morphological characteristics, i.e., smooth, micro-grooved, and porous surfaces, respectively. The tenocytes were seeded on the surfaces of the scaffolds to form tenocyte-scaffold constructs. The constructs were cryopreserved in a vitreous cryoprotectant (CPA) with a multi-step protocol. The cell adhesion to scaffolds was observed with electronic scanning microscopy (SEM). The elongation index of the living tenocytes and ratio of live/dead cell number were examined based on a live/dead dual fluorescent staining technique, and the survival rate of tenocytes was studied with flow cytometry (FC). The results showed the shapes of tenocytes varied between the different groups: flat or polygonal (on smooth surface), spindle (on micro-grooved surface), and spindle or ellipse (on porous surface). After thawing, the porous surface got the most living tenocytes and a higher survival rate, suggesting its potential application for vitreous cryopreservation of engineered tendon constructs.

  3. MINERALIZATION OF RADIOACTIVE WASTES BY FLUIDIZED BED STEAM REFORMING (FBSR): COMPARISONS TO VITREOUS WASTE FORMS, AND PERTINENT DURABILITY TESTING

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2008-12-26

    The Savannah River National Laboratory (SRNL) was requested to generate a document for the Washington State Department of Ecology and the U.S. Environmental Protection Agency that would cover the following topics: (1) A description of the mineral structures produced by Fluidized Bed Steam Reforming (FBSR) of Hanford type Low Activity Waste (LAW including LAWR which is LAW melter recycle waste) waste, especially the cage structured minerals and how they are formed. (2) How the cage structured minerals contain some contaminants, while others become part of the mineral structure (Note that all contaminants become part of the mineral structure and this will be described in the subsequent sections of this report). (3) Possible contaminant release mechanisms from the mineral structures. (4) Appropriate analyses to evaluate these release mechanisms. (5) Why the appropriate analyses are comparable to the existing Hanford glass dataset. In order to discuss the mineral structures and how they bond contaminants a brief description of the structures of both mineral (ceramic) and vitreous waste forms will be given to show their similarities. By demonstrating the similarities of mineral and vitreous waste forms on atomic level, the contaminant release mechanisms of the crystalline (mineral) and amorphous (glass) waste forms can be compared. This will then logically lead to the discussion of why many of the analyses used to evaluate vitreous waste forms and glass-ceramics (also known as glass composite materials) are appropriate for determining the release mechanisms of LAW/LAWR mineral waste forms and how the durability data on LAW/LAWR mineral waste forms relate to the durability data for LAW/LAWR glasses. The text will discuss the LAW mineral waste form made by FBSR. The nanoscale mechanism by which the minerals form will be also be described in the text. The appropriate analyses to evaluate contaminant release mechanisms will be discussed, as will the FBSR test results to

  4. Acanthamoeba keratitis and contact lens wear.

    Science.gov (United States)

    Lindsay, Richard G; Watters, Grant; Johnson, Richard; Ormonde, Susan E; Snibson, Grant R

    2007-09-01

    Acanthamoeba keratitis is a rare but serious complication of contact lens wear that may cause severe visual loss. The clinical picture is usually characterised by severe pain, sometimes disproportionate to the signs, with an early superficial keratitis that is often misdiagnosed as herpes simplex virus (HSV) keratitis. Advanced stages of the infection are usually characterised by central corneal epithelial loss and marked stromal opacification with subsequent loss of vision. In this paper, six cases of contact lens-related Acanthamoeba keratitis that occurred in Australia and New Zealand over a three-year period are described. Three of the patients were disposable soft lens wearers, two were hybrid lens wearers and one was a rigid gas permeable lens wearer. For all six cases, the risk factors for Acanthamoeba keratitis were contact lens wear with inappropriate or ineffective lens maintenance and exposure of the contact lenses to tap or other sources of water. All six patients responded well to medical therapy that involved topical use of appropriate therapeutic agents, most commonly polyhexamethylene biguanide and propamidine isethionate, although two of the patients also subsequently underwent deep lamellar keratoplasty due to residual corneal surface irregularity and stromal scarring. Despite the significant advances that have been made in the medical therapy of Acanthamoeba keratitis over the past 10 years, prevention remains the best treatment and patients who wear contact lenses must be thoroughly educated about the proper use and care of the lenses. In particular, exposure of the contact lenses to tap water or other sources of water should be avoided.

  5. Genomics-Based Identifcation of Microorganisms in Human Ocular Body Fluid

    DEFF Research Database (Denmark)

    Kirstahler, Philipp; Solborg Bjerrum, Søren; Friis-Møller, Alice

    2018-01-01

    Advances in genomics have the potential to revolutionize clinical diagnostics. Here, we examine the microbiome of vitreous (intraocular body fluid) from patients who developed endophthalmitis following cataract surgery or intravitreal injection. Endophthalmitis is an inflammation of the intraocul...... through analyses of whole genome sequence (WGS) assemblies of isolates and metagenomic assemblies. Together, we conclude that genomics-based analyses of human ocular body fluid specimens can provide actionable information relevant to infectious disease management.......Advances in genomics have the potential to revolutionize clinical diagnostics. Here, we examine the microbiome of vitreous (intraocular body fluid) from patients who developed endophthalmitis following cataract surgery or intravitreal injection. Endophthalmitis is an inflammation of the intraocular...... to reduce background DNA in these low microbial biomass samples. We created a curated microbial genome database (>5700 genomes) and designed a metagenomics workflow with filtering steps to reduce DNA sequences originating from: (i) human hosts, (ii) ambiguousness/contaminants in public microbial reference...

  6. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    International Nuclear Information System (INIS)

    Konvalina, I.; Muellerova, I.

    2011-01-01

    The cathode lens is an electron optical element in an emission electron microscope accelerating electrons from the sample, which serves as a source for a beam of electrons. Special application consists in using the cathode lens first for retardation of an illuminating electron beam and then for acceleration of reflected as well as secondary electrons, made in the directly imaging low energy electron microscope or in its scanning version discussed here. In order to form a real image, the cathode lens has to be combined with a focusing magnetic lens or a focusing immersion-magnetic lens, as used for objective lenses of some commercial scanning electron microscopes. These two alternatives are compared with regards to their optical properties, in particular with respect to predicted aberration coefficients and the spot size, as well as the optimum angular aperture of the primary beam. The important role of the final aperture size on the image resolution is also presented.

  7. Lens exposure during brain scans using multidetector row CT scanners: methods for estimation of lens dose.

    Science.gov (United States)

    Suzuki, S; Furui, S; Ishitake, T; Abe, T; Machida, H; Takei, R; Ibukuro, K; Watanabe, A; Kidouchi, T; Nakano, Y

    2010-05-01

    Some recent studies on radiation lens injuries have indicated much lower dose thresholds than specified by the current radiation protection guidelines. The purpose of this research was to measure the lens dose during brain CT scans with multidetector row CT and to assess methods for estimating the lens dose. With 8 types of multidetector row CT scanners, both axial and helical scans were obtained for the head part of a human-shaped phantom by using normal clinical settings with the orbitomeatal line as the baseline. We measured the doses on both eyelids by using an RPLGD during whole-brain scans including the orbit with the starting point at the level of the inferior orbital rim. To assess the effect of the starting points on the lens doses, we measured the lens doses by using 2 other starting points for scanning (the orbitomeatal line and the superior orbital rim). The CTDIvols and the lens doses during whole-brain CT including the orbit were 50.9-113.3 mGy and 42.6-103.5 mGy, respectively. The ratios of lens dose to CTDIvol were 80.6%-103.4%. The lens doses decreased as the starting points were set more superiorly. The lens doses during scans from the superior orbital rim were 11.8%-20.9% of the doses during the scans from the inferior orbital rim. CTDIvol can be used to estimate the lens dose during whole-brain CT when the orbit is included in the scanning range.

  8. [Clinical study on treatment of secondary keratoconus with special designed rigid gas permeable contact lens].

    Science.gov (United States)

    Wang, Dan; Xie, Pei-ying; Zhou, Jian-lan

    2013-04-01

    To investigate the clinical effects of special designed rigid gas permeable contact lens (RGPCL) in the treatment of secondary keratoconus. Retrospective study. The results of correction of secondary keratoconus by the RGPCL in 89 cases (102 eyes) at the Optometry & Ophthalmology Center were analyzed, including history, slit lamp microscope, computer assisted corneal topography, phoropter, corneal endothelial cell examinations and A-scan corneal thickness measurements. We selected and designed the contact lens with different materials for refractive correction according to different corneal deformations. Visual stability and corneal changes were regularly observed. We compared corrected vision, corneal curvature and corneal topography before and after wearing spectacles and RGPCL by using a paired-t test. Secondary keratoconus after keratorefractive operation in 56 cases (67 eyes), including post-LASIK in 53 eyes, post-PRK in 4 eyes and post-RK in 10 eyes were observed. The cornea thickness in the lesion region was less than 0.4 mm, with nebula or macula. Corneal topography showed different local protrusions, Steep K ranged 47.56 D to 69.72 D, corneal astigmatism ranged 4.00 D to 14.00 D, with irregular deformations, visible different degrees matrix strips pattern changes and Fleischer ring. Secondary keratoconus in 31 cases (31 eyes) was developed after corneal injury. The lesions included opaque scar, decrease of corneal endothelial density, multi-deformations and aphakia in 15 eyes. In addition, there were different degrees of damage in pupil, iris, vitreous and retina. Secondary keratoconus in one case (2 eyes) was developed after anti-glaucoma and pediatric cataract extraction operations (with intraocular lens implantation). Another case was secondary to repeated bilateral keratitis episodes, with large macula, mild thinning of cornea, neovascularization and roughness of corneal surface. The uncorrected visual acuity in these eyes was poor. After wearing the

  9. Vitreous hyper-reflective dots in pseudophakic cystoid macular edema assessed with optical coherence tomography.

    Directory of Open Access Journals (Sweden)

    Wilfried Glatz

    Full Text Available This study compares the presence of vitreous hyper-reflective dots (VHDs detected with optical coherence tomography (OCT between eyes with pseudophakic cystoid macular edema (CME and those with no CME after cataract surgery. In addition, we evaluated the impact of VHDs on the responsiveness of pseudophakic CME to cortisone treatment.Department of Ophthalmology, Medical University of Graz, Austria.Retrospective, monocenter case-controlled study.Inclusion criteria for the study group and the control group were CME and no CME within 12 weeks following uneventful phacoemulsification in otherwise healthy eyes, respectively. VHDs (number and size and the macular thickness were assessed with OCT. Furthermore, the number of peribulbar or intravitreal steroid injections was assessed.A total of 284 eyes from 267 patients were analyzed, among which 119 met the inclusion criteria for the study (n = 63 and the control group (n = 56. VHDs were observed in 54 (85.7% study eyes and 21 (37.5%, p = 0.013 control eyes. The number of VHDs was 3.9±3.4 in the study group and 0.7±1 in the control group (p<0.001. The size of the VHDs was 33.5±9.1 μm and 36.6±17.9 μm in the study and control groups, respectively (p = 0.978. Overall, the number of VHDs correlated with central subfield thickness (r = 0.584, p<0.001, cube volume (r = 0.525, p<0.001, and postoperative best-corrected visual acuity (BCVA (r = -0.563, p<0.001. The number of VHDs did not correlate with the frequency of peribulbar or intravitreal steroid injections.VHDs occurred more often in eyes with CME than in eyes without CME following cataract surgery. In addition, the number of VHDs had an impact on the extent of macular thickening and subsequently postoperative BCVA. No correlation was found between the number of VHDs and the frequency of required peribulbar or intravitreal steroid injections.

  10. Development of Powerhouse Using Fresnel lens

    Directory of Open Access Journals (Sweden)

    Al-Dohani Nawar Saif

    2018-01-01

    Full Text Available Solar energy is an alternative source of renewable energy. Sultanate of Oman government showed initiation on utilization of solar energy for domestic and industrial applications. Fresnel lens is one of the methods to collect maximum energy by gathering heat of the sun in the concentrated form (using solar collectors. Earlier research work discloses that Fresnel lens gave better result in terms of power output and produces lower heat loss as compared to linear –parabolic solar collectors. In this work, development of a proto Fresnel lens power house was made to generate electricity. The focused heat from Fresnel lens was used to heat the molten salt in a heat exchanger to produce the steam. The generated steam was used to rotate the steam engine coupled to a generator. In the current work, a maximum power of 30 W was produced. In addition, comparative study was carried out regarding solar salts and heat exchanger materials to understand the Fresnel powerhouse performance. Overall the present study gave valuable information regarding usage of Fresnel lens for electricity generation in Oman.

  11. Non-compliance in contact lens wear.

    Science.gov (United States)

    Claydon, B E; Efron, N

    1994-10-01

    Non-compliance is emerging as a critical issue in the contact lens field. This problem has been studied at depth in general health care situations and is seen as the responsibility of both practitioner and patient (client) working in a health care partnership. The contact lens practitioner and patient present a specific case for the study of non-compliance in areas such as hygiene, solution use, appointment attendance and wearing times. From 40 to 91% of contact lens patients have been reported as non-complaint in the use of recommended care and maintenance regimens and many of these are confused or ignorant about their behaviour. In order to arrive at a general set of conclusions from the studies published to date, it is important to understand the methodology of each study, it purpose, the definition of non-compliance used and the way the results were analysed and described. This review summarizes the research into non-compliance in the contact lens field to data. A set of general conclusions is drawn and a model for compliance in the context of contact lens practice is proposed.

  12. Spherical aberration in contact lens wear.

    Science.gov (United States)

    Lindskoog Pettersson, A; Jarkö, C; Alvin, A; Unsbo, P; Brautaset, R

    2008-08-01

    The aim of the present studies was to investigate the effect on spherical aberration of different non custom-made contact lenses, both with and without aberration control. A wavefront analyser (Zywave, Bausch & Lomb) was used to measure the aberrations in each subject's right eye uncorrected and with the different contact lenses. The first study evaluated residual spherical aberration with a standard lens (Focus Dailies Disposable, Ciba Vision) and with an aberration controlled contact lens (ACCL) (Definition AC, Optical Connection Inc.). The second study evaluated the residual spherical aberrations with a monthly disposable silicone hydrogel lens with aberration reduction (PureVision, Bausch & Lomb). Uncorrected spherical aberration was positive for all pupil sizes in both studies. In the first study, residual spherical aberration was close to zero with the standard lens for all pupil sizes whereas the ACCL over-corrected spherical aberration. The results of the second study showed that the monthly disposable lens also over-corrected the aberration making it negative. The changes in aberration were statistically significant (plenses. Since the amount of aberration varies individually we suggest that aberrations should be measured with lenses on the eye if the aim is to change spherical aberration in a certain direction.

  13. A lazy way to design infrared lens

    Science.gov (United States)

    Qiu, RongSheng; Wu, JianDong; Chen, LongJiang; Yu, Kun; Pang, HaoJun; Hu, BaiZhen

    2017-08-01

    We designed a compact middle-wave infrared (MWIR) lens with a large focal length ratio (about 1.5:1), used in the 3.7 to 4.8 μm range. The lens is consisted of a compact front group and a re-imaging group. Thanks to the compact front group configuration, it is possible to install a filter wheel mechanism in such a tight space. The total track length of the lens is about 50mm, which includes a 2mm thick protective window and a cold shield of 12mm. The full field of view of the lens is about 3.6°, and F number is less than 1.6, the image circle is about 4.6mm in diameter. The design performance of the lens reaches diffraction limitation, and doesn't change a lot during a temperature range of -40°C +60°C. This essay proposed a stepwise design method of infrared optical system guided by the qualitative approach. The method fully utilize the powerful global optimization ability, with a little effort to write code snippet in optical design software, frees optical engineer from tedious calculation of the original structure.

  14. TESS Lens-Bezel Assembly Modal Testing

    Science.gov (United States)

    Dilworth, Brandon J.; Karlicek, Alexandra

    2017-01-01

    The Transiting Exoplanet Survey Satellite (TESS) program, led by the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT) will be the first-ever spaceborne all-sky transit survey. MIT Lincoln Laboratory is responsible for the cameras, including the lens assemblies, detector assemblies, lens hoods, and camera mounts. TESS is scheduled to be launched in August of 2017 with the primary goal to detect small planets with bright host starts in the solar neighborhood, so that detailed characterizations of the planets and their atmospheres can be performed. The TESS payload consists of four identical cameras and a data handling unit. Each camera consists of a lens assembly with seven optical elements and a detector assembly with four charge-coupled devices (CCDs) including their associated electronics. The optical prescription requires that several of the lenses are in close proximity to a neighboring element. A finite element model (FEM) was developed to estimate the relative deflections between each lens-bezel assembly under launch loads to predict that there are adequate clearances preventing the lenses from making contact. Modal tests using non-contact response measurements were conducted to experimentally estimate the modal parameters of the lens-bezel assembly, and used to validate the initial FEM assumptions. Key Words Non-contact measurements, modal analysis, model validation

  15. Provision of dosimeters by official monitoring services for eye lens dose estimation

    International Nuclear Information System (INIS)

    Engelhardt, J.; Martini, E.

    2013-01-01

    Recent epidemiological studies are implying that the radio sensitivity of the eye lens is much higher than supposed in the past. International recommendations and standards demand to lower down the annual limit of the eye lens organ dose to 20 mSv. Since about 10 years German monitoring services offer partial-body dosimeters fixed on the head or on glasses for monitoring the eye lens dose. These dosimeters are optimized to measure the (surface) personal dose equivalent H p (0,07) from 0,5 mSv up to 10 Sv, which clearly overestimate the organ dose of the eye lens. With special features like different calibrations partial-body dosimeters should be applicable for legal dosimetry to avoid the development of special H p (3) dosimeters. Accepting the right way for wearing these dosimeters it is important to get the right results. Practical experiences are shown with measuring results and the difficulties of rounding the exact measuring values to discrete dose steps. Closing this article we point to still missing legal basis and open questions regarding to type testing procedures. (orig.)

  16. Comparison of two Nd:YAG laser posterior capsulotomy: cruciate pattern vs circular pattern with vitreous strand cutting

    Directory of Open Access Journals (Sweden)

    Jin-Soo Kim

    2018-02-01

    Full Text Available AIM: To investigate the effects and safety of neodymium: yttrium-aluminium-garnet (Nd:YAG laser posterior capsulotomy with vitreous strand cutting METHODS: A total of 40 eyes of 37 patients with symptomatic posterior capsular opacity (PCO were included in this prospective randomized study and were randomly subjected to either cruciate pattern or round pattern Nd:YAG posterior capsulotomy with vitreous strand cutting (modified round pattern. The best corrected visual acuity (BCVA, intraocular pressure (IOP, refractive error, endothelial cell count (ECC, anterior segment parameters, including anterior chamber depth (ACD and anterior chamber angle (ACA were measured before and 1mo after the laser posterior capsulotomy. RESULTS: In both groups, the BCVA improved significantly (P<0.001 for the modified round pattern group, P=0.001 for the cruciate pattern group; the IOP and ECC did not significantly change. The ACD significantly decreased (P<0.001 for both and the ACA significantly increased (P=0.001 for the modified round pattern group and P=0.034 for the cruciate group. The extent of changes in these parameters was not significantly different between the groups. CONCLUSION: Modified round pattern Nd:YAG laser posterior capsulotomy is an effective and safe method for the treatment of PCO. This method significantly changes the ACD and ACA, but the change in refraction is not significant. Modified round pattern Nd:YAG laser posterior capsulotomy can be considered a good alternative procedure in patients with symptomatic PCO.

  17. Assessment of the effect of intravitreal triamcinolone acetonide on the chorioretinal and vitreous inflammatory reaction to cryotherapy in rabbits

    Directory of Open Access Journals (Sweden)

    Eugênio Santana de Figueirêdo

    2012-10-01

    Full Text Available PURPOSE: To evaluate the inflammatory response in the choroid, retina and vitreous in rabbit eyes underwent cryotherapy followed by intravitreal triamcinolone acetonide and to compare with those underwent cryotherapy followed by intravitreal injection of saline solution. METHODS: This is a prospective case-control study. Surgical procedures were performed in eleven rabbits. Two animals were excluded because they did not complete the postoperative period or had intraoperative or postoperative complications. All rabbits underwent superior temporal peritomy and transscleralcryotherapy in both eyes. After cryotherapy, animals received intravitreal injection of triamcinolone acetonide in one eye and saline solution in the fellow eye. Animals were sacrificed seven days after the procedure and their eyes were enucleated. Histological sections of eyeballs were prepared and the vitreous humor was aspirated. The count of inflammatory cells was performed by light microscopy. RESULTS: Histological sections of both eyes of nine rabbits were analyzed. Inflammatory cells were found only in the choroid. There was no statistically significant difference in the number of inflammatory cells between the two groups, regardless of cell type analyzed. CONCLUSION: This study showed no statistically significant difference between the use or absence of intravitreal triamcinolone acetonide in the inflammatory response to cryotherapy in rabbit eyes. Studies with larger samples are needed to confirm the trend of this paper.

  18. Evaluation of 292 ocular swabs, vitreous and aqueous cultures in pathologies with severe prognosis during a 24-month observation period

    Directory of Open Access Journals (Sweden)

    Franco Giardini

    2010-12-01

    Full Text Available Introduction. Different part of the eye can be infected by bacteria, fungi, parasites and viruses (5. The aim of this study was to assess the importance of ocular swabs culture in pathologies with severe prognosis. Methods.We examined 292 patients with a severe diseases: 98% of those used topical and/or systemic antibiotic therapy.All sample were cultured both into a chocolate agar medium and into an Haemophilus selective agar and, at the same time, inoculated onto a modified blood cuture. Results. 75 out of 292 (25.7% patients tested negative.The most representative microorganisms were: Coagulase-negative staphylococci (CNS (20%, Staphylococcus aureus (12%, member of the Pseudomonadaceae family (10.9%, Streptococcus pneumoniae (9%, alpha haemolytic streptococci (8.2%, Fungus and Yeast (5.4%. Considering the type of cultures: 54.5% of the vitreous cultures were positive and 45.5% were negative; 38.2% of the positive cultures were referred to endophthalmitis, with prevalence of CNS (32.5% and S. aureus (22.9%, while 27.6% were due to an abscesces, with prevalence of members of the Pseudomonadaceae family (53.3%, CNS (23.3% and S. pneumoniae (16.7%. Conclusions. This data suggest the importance of the ocular swabs, vitreous and aqueous cultures in the therapeutic approach of the diseases with a severe prognosis and emphasize the good performance of the modified Bactec Plus system.

  19. Acanthamoeba, bacterial, and fungal contamination of contact lens storage cases.

    Science.gov (United States)

    Gray, T B; Cursons, R T; Sherwan, J F; Rose, P R

    1995-01-01

    BACKGROUND--Microbial corneal infection is the most serious complication of contact lens wear. Contact lens cases are a recognised potential source of pathogens associated with corneal ulcers. METHODS--This survey established the incidence of protozoal, bacterial, and fungal contact lens case contamination in 101 asymptomatic daily wear cosmetic contact lens wearers from a domiciliary contact lens practice. RESULTS--Eighty two (81%) contact lens cases were found to be contaminated, with 19 (19%) sterile. Of all contact lens cases, 78 (77%) grew bacteria, 24 (24%) fungi, and 20 (20%) protozoa. Acanthamoeba spp were isolated from eight (8%) contact lens cases. Fifty six (55%) contact lens cases yielded mixed bacterial contamination. This is the first contact lens case survey in which hydrogen peroxide disinfection was the major method of contact lens disinfection (75% of subjects) and no home made saline was used. All the contaminating organisms were shown to possess the enzyme catalase that breaks down hydrogen peroxide to oxygen and water. The polymicrobial nature of the biofilms found in many contact lens cases is illustrated electron micrographically. CONCLUSION--Based on data from this and previous studies, the authors conclude with recommendations for contact lens wearers: (1) regular scrubbing of contact lens case interior to disrupt biofilms; (2) exposure of contact lens case to very hot water (> or = 70 degrees C) will kill Acanthamoeba contaminants; (3) allow contact lens case to air dry between uses; (4) if hydrogen peroxide disinfection is preferred, use a two step system; (5) replace contact lens case regularly. Images PMID:7626578

  20. Vitrectomía pars plana y reimplante de lente intraocular en surco Pars plana vitrectomy and intraocular lens repositioning in the sulcus

    Directory of Open Access Journals (Sweden)

    Alejandro Guerra García

    2010-01-01

    Full Text Available Se presentó un caso de lente intraocular luxado a vítreo en paciente con conteo bajo de células endoteliales e intolerancia a lentes de contacto. Se practicó vitrectomía pars plana con reimplante de lente en surco ciliar con el objetivo de demostrar la fiabilidad de la técnica para casos que presenten condiciones adecuadas y situaciones especiales. Se revisó la bibliografía para conocer las tendencias actuales con respecto al manejo de esta patología. El paciente alcanzó una agudeza visual de 20/30. El lente permaneció estable en el surco 3 meses después de practicada la vitrectomía. El manejo de esta entidad debe ser personalizado. La técnica utilizada debe ser siempre la primera opción de tratamiento y parece ser segura en casos cuidadosamente escogidos.A case of dislocated intraocular lens moved to the vitreous cavity in a patient with low endothelial cell count and contact lens intolerance was reported. A pars plana vitrectomy with lens repositioning was performed to demonstrate the safety of this technique for some special cases under adequate conditions. The literature was reviewed to learn about the current management of this pathology. Finally, patient's best visual acuity was 20/30. The stability of the lens was confirmed three month l after the vitrectomy. Management of this disorder should be customized. This technique should be considered as the first option of treatment and seems to be safe in selected cases.

  1. Characterization of lens based photoacoustic imaging system

    Directory of Open Access Journals (Sweden)

    Kalloor Joseph Francis

    2017-12-01

    Full Text Available Some of the challenges in translating photoacoustic (PA imaging to clinical applications includes limited view of the target tissue, low signal to noise ratio and the high cost of developing real-time systems. Acoustic lens based PA imaging systems, also known as PA cameras are a potential alternative to conventional imaging systems in these scenarios. The 3D focusing action of lens enables real-time C-scan imaging with a 2D transducer array. In this paper, we model the underlying physics in a PA camera in the mathematical framework of an imaging system and derive a closed form expression for the point spread function (PSF. Experimental verification follows including the details on how to design and fabricate the lens inexpensively. The system PSF is evaluated over a 3D volume that can be imaged by this PA camera. Its utility is demonstrated by imaging phantom and an ex vivo human prostate tissue sample.

  2. Freeform micromachining of an infrared Alvarez lens

    Science.gov (United States)

    Smilie, Paul J.; Dutterer, Brian S.; Lineberger, Jennifer L.; Davies, Matthew A.; Suleski, Thomas J.

    2011-02-01

    In 1967, Luis Alvarez introduced a novel concept for a focusing lens whereby two transmitting elements with cubic polynomial surfaces yield a composite lens of variable focal length with small lateral shifts. Computer simulations have demonstrated the behavior of these devices, but fabricating the refractive cubic surfaces of the types needed with adequate precision and depth modulation has proven to be challenging using standard methods, and, to the authors' knowledge, Alvarez lens elements have not been previously machined in infrared materials. Recent developments in freeform diamond machining capability have enabled the fabrication of such devices. In this paper, we discuss the fabrication of freeform refractive Alvarez elements in germanium using diamond micro-milling on a five-axis Moore Nanotech® 350FG Freeform Generator. Machining approaches are discussed, and measurements of surface figure and finish are presented. Initial experimental tests of optical performance are also discussed.

  3. Invited review article: the electrostatic plasma lens.

    Science.gov (United States)

    Goncharov, Alexey

    2013-02-01

    The fundamental principles, experimental results, and potential applications of the electrostatic plasma lens for focusing and manipulating high-current, energetic, heavy ion beams are reviewed. First described almost 50 years ago, this optical beam device provides space charge neutralization of the ion beam within the lens volume, and thus provides an effective and unique tool for focusing high current beams where a high degree of neutralization is essential to prevent beam blow-up. Short and long lenses have been explored, and a lens in which the magnetic field is provided by rare-earth permanent magnets has been demonstrated. Applications include the use of this kind of optical tool for laboratory ion beam manipulation, high dose ion implantation, heavy ion accelerator injection, in heavy ion fusion, and other high technology.

  4. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-12-19

    The gain of an antenna can be enhanced through the integration of a lens, however this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, with a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB giving a peak gain of about 12.9 dBi at 8.8 GHz.

  5. An "ESA-affordable" Laue-lens

    DEFF Research Database (Denmark)

    Lund, Niels

    2005-01-01

    With ESA's INTEGRAL mission gamma-ray astronomy has advanced to the point where major scientific advances must be expected from detailed studies of the many new point sources. The interest in developing focusing telescopes operating in the soft gamma-ray regime up to 1 MeV is therefore mounting r...... constraints of a specific medium size launch vehicle. The introduction of the lens mass as a primary design driver has some surprising effects for the choice of material for the crystals and new tradeoff considerations are introduced....... rapidly. Telescopes based on Laue diffraction of gamma-rays from crystals appear as one promising route, although the practical difficulties of realizing a large scale Laue lens are certainly not small. In this paper I have attempted to develop an optimized lens design considering the size and mass...

  6. The effectiveness of soft contact lens disinfection systems against Acanthamoeba on the lens surface.

    Science.gov (United States)

    Liedel, K K; Begley, C G

    1996-03-01

    This investigation compared the efficacy of three widely used contact lens disinfection systems against an ocular isolate of Acanthamoeba polyphaga. Twenty-seven worn Ciba NewVues lenses were quartered, heat sterilized and inoculated with Acanthamoeba. Lens quarters were then randomly assigned to three experimental groups, with Group A lenses exposed to cleaner and saline rinse only, Group B to disinfection only, and Group C to both cleaner and disinfection. One quarter of each lens served as a control and the other three quarters were experimental. Quantification of viable Acanthamoeba remaining on the lens was performed after each step of the disinfection process. Group A lenses showed no significant difference between the treatments, or the treatments and the control. Group B lenses demonstrated a significant difference (p = 0.0001) between the treatments and the control. In Group C (cleaning and disinfection), the control lens quarters were significantly different (p = 0.037) from the experimental group, but there was no significant difference between the treatments. All three disinfection regimens were very effective in reducing the number of viable Acanthamoeba on the contact lens surface. In the absence of proper cleaning (Group B), AOSept was the most effective of the three. These results also show the importance of thoroughly rubbing the contact lens surface to decrease the number of Acanthamoeba.

  7. Non-compliance with lens care and maintenance in diabetic contact lens wearers.

    Science.gov (United States)

    O'Donnell, Clare; Efron, Nathan

    2004-11-01

    We hypothesize that diabetic contact lens wearers may represent a special group displaying higher levels of compliance with their lens care regimens as a result of learned behaviour relating to maintenance of their diabetic condition. To test this hypothesis, a prospective, single centre, controlled, masked study was performed whereby 29 diabetic contact lens patients and 29 non-diabetic control subjects were issued with disposable hydrogel contact lenses and a multipurpose lens care regimen. All participants were given identical instruction on lens care and maintenance. Compliance levels were assessed at a 12-month aftercare appointment by demonstration and questionnaire. Twenty-four different aspects of compliance were scored, 12 by observation and 12 by questionnaire report, of which only two showed a significant difference between the diabetic and control groups. Although the combined population of contact lens wearers was generally compliant, there were examples of non-compliance in both groups. Neither the duration of diabetes nor the degree of metabolic control appeared to have a significant effect on compliance. The results suggest that eye care practitioners cannot assume that diabetic patients will be more compliant with contact lens care and maintenance than non-diabetic patients.

  8. Analytic models of plausible gravitational lens potentials

    International Nuclear Information System (INIS)

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune

    2009-01-01

    Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sérsic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sérsic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses

  9. Photonic crystal based polarization insensitive flat lens

    Science.gov (United States)

    Turduev, M.; Bor, E.; Kurt, H.

    2017-07-01

    The paper proposes a new design of an inhomogeneous artificially created photonic crystal lens structure consisting of annular dielectric rods to efficiently focus both transverse electric and transverse magnetic polarizations of light into the same focal point. The locations of each individual cell that contains the annular dielectric rods are determined according to a nonlinear distribution function. The inner and outer radii of the annular photonic dielectric rods are optimized with respect to the polarization insensitive frequency response of the transmission spectrum of the lens structure. The physical background of the polarization insensitive focusing mechanism is investigated in both spatial and frequency domains. Moreover, polarization independent wavefront transformation/focusing has been explored in detail by investigating the dispersion relation of the structure. Corresponding phase index distribution of the lens is attained for polarization insensitive normalized frequency range of a/λ  =  0.280 and a/λ  =  0.300, where a denotes the lattice constant of the designed structure and λ denotes the wavelength of the incident light. We show the wave transformation performance and focal point movement dynamics for both polarizations of the lens structure by specially adjusting the length of the structure. The 3D finite-difference time domain numerical analysis is also performed to verifiy that the proposed design is able to focus the wave regardless of polarization into approximately the same focal point (difference between focal distances of both polarizations stays below 0.25λ) with an operating bandwidth of 4.30% between 1476 nm and 1541 nm at telecom wavelengths. The main superiorities of the proposed lens structure are being all dielectric and compact, and having flat front and back surfaces, rendering the proposed lens design more practical in the photonic integration process in various applications such as optical switch

  10. Effect of infrared radiation on the lens

    Directory of Open Access Journals (Sweden)

    Aly Eman

    2011-01-01

    Full Text Available Background: Infrared (IR radiation is becoming more popular in industrial manufacturing processes and in many instruments used for diagnostic and therapeutic application to the human eye. Aim : The present study was designed to investigate the effect of IR radiation on rabbit′s crystalline lens and lens membrane. Materials and Methods: Fifteen New Zealand rabbits were used in the present work. The rabbits were classified into three groups; one of them served as control. The other two groups were exposed to IR radiation for 5 or 10 minutes. Animals from these two irradiated groups were subdivided into two subgroups; one of them was decapitated directly after IR exposure, while the other subgroup was decapitated 1 hour post exposure. IR was delivered from a General Electric Lamp model 250R 50/10, placed 20 cm from the rabbit and aimed at each eye. The activity of Na + -K + ATPase was measured in the lens membrane. Soluble lens proteins were extracted and the following measurements were carried out: estimation of total soluble protein, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE and Fourier transform infrared (FTIR spectroscopy. For comparison between multiple groups, analysis of variance was used with significance level set at P < 0.001. Results: The results indicated a change in the molecular weight of different lens crystalline accompanied with changes in protein backbone structure. These changes increased for the groups exposed to IR for 10 minutes. Moreover, the activity of Na + -K + ATPase significantly decreased for all groups. Conclusions: The protein of eye lens is very sensitive to IR radiation which is hazardous and may lead to cataract.

  11. Analysis of the Cochrane Review: Anti-vascular Endothelial Growth Factor for Prevention of Postoperative Vitreous Cavity Hemorrhage after Vitrectomy for Proliferative Diabetic Retinopathy. Cochrane Database Syst Rev. 2015;8:CD008214.

    Directory of Open Access Journals (Sweden)

    David Cordeiro Sousa

    2017-08-01

    Full Text Available Postoperative vitreous hemorrhage is a complication following vitrectomy for proliferative diabetic retinopathy, delaying visual recovery and making fundus examination and disease follow-up more difficult. Anti-vascular endothelial growth factor drugs such as bevacizumab, when injected in the vitreous cavity, reduce vascular proliferation and their use has been proposed to reduce the incidence of postoperative vitreous hemorrhage. The authors of this Cochrane systematic review evaluated all randomized controlled trials on the pre- or intraoperative use of anti-vascular endothelial growth factor to reduce postoperative vitreous hemorrhage occurrence after vitrectomy in patients with proliferative diabetic retinopathy. The results suggested that the use of intravitreal bevacizumab was effective in reducing early postoperative vitreous hemorrhage (i.e. at four weeks occurrence, with a good safety profile. This work aims to summarize and discuss the findings and clinical implications of this Cochrane systematic review.

  12. The corneal stroma during contact lens wear.

    Science.gov (United States)

    Jalbert, Isabelle; Stapleton, Fiona

    2005-03-01

    Recent technological advances have lead to novel descriptions of the microanatomy of the corneal stroma. In the first section of this review, these findings and the role they play in the maintenance of vital properties such as corneal transparency, mechanical strength, homeostasis, wound-healing response and metabolism are described. In the second part, contact lens induced stromal alterations such as acidosis, oedema, striae, thinning and opacities are reviewed as well as the more recently described phenomenon of microdot deposits and keratocyte loss with an emphasis on how lens wearing stromal effects can be minimised.

  13. Sterilization potential of contact lens solutions

    Directory of Open Access Journals (Sweden)

    Dada Vijay

    1988-01-01

    Full Text Available In a dynamic field of Contact Lens Solutions maintenance of high standards of anti-microbial activity is a must Resterilization Activity Time′ is a universally accepted yardstick for such an evaluation. In this study eight brands of indigenous popular solutions alongwith two FDA approved solutions were tested for their sterilization efficacy: Standardized suspensions of Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus fumigatus were used for the purpose. It was observed that the contact lens solutions available ir, the domestic market were not upto the mark Suggestions for improvement have also been made.

  14. Rotman lens for mm-wavelengths

    Science.gov (United States)

    Hall, Leonard T.; Hansen, Hedley J.; Abbott, Derek

    2002-11-01

    The 77 GHz band has been reserved for intelligent cruise control in luxury cars and some public transport services in America and the United Kingdom. The Rotman lens offers a cheap and compact means to extend the single beam systems generally used, to fully functional beam staring arrangements. Rotman lenses have been built for microwave frequencies with limited success. The flexibility of microstrip transmission lines and the advent of fast accurate simulation packages allow practical Rotman lenses to be designed at mm-wavelengths. This paper discusses the limitations of the conventional design approach and predicts the performance of a new Rotman lens designed at 77 GHz.

  15. Pulse transformer for the AA lithium lens

    CERN Document Server

    CERN PhotoLab

    1980-01-01

    The antiprotons emanating from the target were initially focused by a magnetic horn. Later on, a Li-lens was used during operation for the SPS collider, until 1992. A Li-rod (130 mm long, 34 mm in diameter) constituted the secondary of a 1:23 pulse-transformer. The half-sine pulse rose to 1000 kA in 900 microsec. The angular acceptance was 95 mrad. In operation after 1992, for LEAR only, a more modest Li-lens was used (155 mm long, diameter 20 mm, 480 kA, risetime 240 microsec, angular acceptance 75 mrad).

  16. Immunochemical analyses of soluble lens proteins in some marine fishes

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    Soluble eye lens proteins of 10 fishes, belonging to the families Clupeidae, Hemirhamphidae, Lactaridae, Scombridae, Stromatidae, Psettodidae, Bothidae and Soleidae were studied by immunoelectrophoresis using the lens antiserum of Sardinella...

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

    Science.gov (United States)

    ... Cataract Surgery vs. Laser-Assisted Cataract Surgery Cataract Vision Simulator Cataract Pictures and Videos: What Do ... Mar. 27, 2018 An intraocular lens (or IOL) is a tiny, artificial lens for the eye. It replaces the eye's ...

  18. Lens autofluorescence is not increased at high altitude

    DEFF Research Database (Denmark)

    Kessel, Line; Kofoed, Peter Kristian; Zubieta-Calleja, Gustavo

    2010-01-01

    PURPOSE: To study the relation between ambient environmental ultraviolet radiation exposure and lens fluorescence. METHODS: Non-invasive lens fluorometry measurements were compared in healthy Bolivian and Danish subjects. Background ultraviolet radiation was 4.5 times higher in Bolivia than in De...... living at sea level at 55 degrees northern latitude. These results suggest that lens ageing, as assessed by lens autofluorometry, is independent of exposure to ultraviolet radiation....

  19. 21 CFR 886.1420 - Ophthalmic lens gauge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic lens gauge. 886.1420 Section 886.1420...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1420 Ophthalmic lens gauge. (a) Identification. An ophthalmic lens gauge is a calibrated device intended to manually measure the curvature of a...

  20. In vivo study of lens regeneration in Rana cyanophlyctis under ...

    African Journals Online (AJOL)

    SAM

    2014-03-12

    Mar 12, 2014 ... enhanced the percentage lens regeneration not only in young tadpoles but also in froglets. Lens regeneration ability ... Influence of vitamin A and ascorbic acid on lens regeneration in young, mature tadpoles and froglets of the frog Rana cyanophlyctis. Group .... ingested by macrophages. Dorsal iris cells ...

  1. 21 CFR 800.10 - Contact lens solutions; sterility.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Contact lens solutions; sterility. 800.10 Section...) MEDICAL DEVICES GENERAL Requirements for Specific Medical Devices § 800.10 Contact lens solutions... ophthalmic use, including contact lens solutions, should be sterile. It is further evident that such...

  2. Initial Experience With Posterior Chamber Intraocular Lens Implant ...

    African Journals Online (AJOL)

    The results of extracapsular cataract extraction with posterior chamber intraocular lens implant at the Jos University Teaching Hospital are reviewed. The results suggest that despite lack of facilities to calculate the lens power for emmetropia, the use of a standard lens of about 19.0D will provide a good number of our ...

  3. Vitrectorhexis and lens aspiration with posterior chamber intraocular lens implantation in spherophakia.

    Science.gov (United States)

    Al-Haddad, Christiane; Khatib, Lama

    2012-07-01

    We describe a technique that uses the vitrector to perform successful lens aspiration and posterior chamber intraocular lens (IOL) implantation in children with spherophakia and anterior lens subluxation. After an anterior chamber maintainer is placed, the ocutome is introduced through a limbal incision to perform a circular vitrectorhexis to avoid excessive manipulation of the unstable lens followed by gentle cortex aspiration. A foldable IOL is injected into the sulcus (3-piece IOL) or bag (1-piece IOL) if the capsule is sufficiently stable. Through a pars plana incision, the ocutome is then used to perform a posterior capsulotomy to prevent late posterior capsule opacification. In our patient, sulcus IOL placement was more stable than in-the-bag placement. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  4. Solar powered desalination system using Fresnel lens

    Science.gov (United States)

    Sales, M. T. B. F.

    2016-11-01

    The Philippines is surrounded by coastal areas and these areas can be a potential source for potable water. This study aims to design and construct a solar powered desalination system using Fresnel lens. The experimental study was conducted using polluted salt water for the sample and desalination was carried out using the designed system. The desalination system was composed of the solar concentrator, solar still and the condenser system. The Fresnel lens was made of acrylic plastic and was an effective solar concentrator. Solar stills made of dark colored glass bottles were effective in absorbing the solar energy. The condenser system made of polybutylene and polystyrene were effective in condensing the vapor at ambient temperature. The shortest time of vaporization of the salt water was at 293 sec and the optimum angle of position of the lens was 36.42°. The amount of condensate collected was directly proportional to the amount of salt water in the solar still. The highest mean efficiency of the designed set-up was 34.82%. The water produced by the solar powered desalination system using Fresnel lens passed the standards set by WHO (World Health Organization) for drinking water.

  5. Electronic states in a quantum lens

    International Nuclear Information System (INIS)

    Rodriguez, Arezky H.; Trallero-Giner, C.; Ulloa, S. E.; Marin-Antuna, J.

    2001-01-01

    We present a model to find analytically the electronic states in self-assembled quantum dots with a truncated spherical cap (''lens'') geometry. A conformal analytical image is designed to map the quantum dot boundary into a dot with semispherical shape. The Hamiltonian for a carrier confined in the quantum lens is correspondingly mapped into an equivalent operator and its eigenvalues and eigenfunctions for the corresponding Dirichlet problem are analyzed. A modified Rayleigh-Schro''dinger perturbation theory is presented to obtain analytical expressions for the energy levels and wave functions as a function of the spherical cap height b and radius a of the circular cross section. Calculations for a hard wall confinement potential are presented, and the effect of decreasing symmetry on the energy values and eigenfunctions of the lens-shape quantum dot is studied. As the degeneracies of a semicircular geometry are broken for b≠a, our perturbation approach allows tracking of the split states. Energy states and electronic wave functions with m=0 present the most pronounced influence on the reduction of the lens height. The method and expressions presented here can be straightforwardly extended to deal with more general Hamiltonians, including strains and valence-band coupling effects in Group III--V and Group II--VI self-assembled quantum dots

  6. Surgical treatment of hereditary lens subluxations.

    Science.gov (United States)

    Ozdek, Sengul; Sari, Ayca; Bilgihan, Kamil; Akata, Fikret; Hasanreisoglu, Berati

    2002-01-01

    To evaluate the effectiveness and results of pars plana vitreolensectomy approach with transscleral fixation of intraocular lens in hereditary lens subluxations. Fifteen eyes of 9 consecutive patients with a mean age of 12.8+/-6.2 years (6-26 years) with hereditary lens subluxation were operated on and the results were evaluated in a prospective study. Surgery was considered if best spectacle corrected visual acuity (BSCVA) was less than 20/70. All eyes underwent a 2-port pars plana vitreolensectomy and transscleral fixation of an intraocular lens (IOL). The mean follow-up period was 12.6+/-7.5 months (6-22 months). There was no major intraoperative complication. Preoperatively, 8 eyes (53.3%) had a BSCVA of counting fingers (CF) and 7 eyes (46.6%) had a BSCVA of 20/200 to 20/70. Postoperatively, 14 eyes (93.3%) had a BSCVA of 20/50 or better. None of the patients had IOL decentration or intraocular pressure (IOP) increase during the follow-up period. There was a macular hole formation in 1 eye postoperatively. The early results of pars plana vitreolensectomy with IOL implantation using scleral fixation technique had shown that it not only promises a rapid visual rehabilitation but it is also a relatively safe method. More serious complications, however, may occur in the long term.

  7. READING SCRIPTURE THROUGH A MYSTICAL LENS

    African Journals Online (AJOL)

    Reading scripture through a mystical lens. 144 the illuminatory function of scripture which confirms and explains experience, rather than in its philological or scientific status. Elisabeth often juxtaposes several texts when quoting from memory and the biblical foundation of her writings is clearly evident in certain cases which ...

  8. Corneal ring infiltration in contact lens wearers

    Directory of Open Access Journals (Sweden)

    Seyed Ali Tabatabaei

    2017-01-01

    Full Text Available To report a case of atypical sterile ring infiltrates during wearing soft silicone hydrogel contact lens due to poor lens care. A 29-year-old woman presented with complaints of pain, redness, and morning discharge. She was wearing soft silicone hydrogel contact lens previously; her current symptoms began 1 week before presentation. On examination, best-corrected visual acuity was 20/40 in that eye. Slit-lamp examination revealed dense, ring-shaped infiltrate involving both the superficial and deep stromal layers with lucid interval to the limbus, edema of the epithelium, epithelial defect, and vascularization of the superior limbus. Cornea-specific in vivo laser confocal microscopy (Heidelberg Retina Tomograph 2 Rostock Cornea Module, HRT 2-RCM, Heidelberg Engineering GmbH, Dossenheim, Germany revealed Langerhans cells and no sign of Acanthamoeba or fungal features, using lid scraping and anti-inflammatory drops; her vision completely recovered. We reported an atypical case of a sterile corneal ring infiltrate associated with soft contact lens wearing; smear, culture, and confocal microscopy confirmed a sterile inflammatory reaction.

  9. Potential pre-cataractous markers induced by low-dose radiation effects in cultured human lens cells

    Science.gov (United States)

    Blakely, E.; McNamara, M.; Bjornstad, K.; Chang, P.

    The human lens is one of the most radiosensitive organs of the body. Cataract, the opacification of the lens, is a late-appearing response to radiation damage. Recent evidence indicates that exposure to relatively low doses of space radiation are associated with an increased incidence and early appearance of human cataracts (Cucinotta et al., Radiat. Res. 156:460-466, 2001). Basic research in this area is needed to integrate the early responses of various late-responding tissues into our understanding and estimation of radiation risk for space travel. In addition, these studies may contribute to the development of countermeasures for the early lenticular changes, in order to prevent the late sequelae. Radiation damage to the lens is not life threatening but, if severe, can affect vision unless surgically corrected with synthetic lens replacement. The lens, however, may be a sensitive detector of radiation effects for other cells of ectodermal origin in the body for which there are not currently clear endpoints of low-dose radiation effects. We have investigated the dose-dependent expression of several radiation-responsive endpoints using our in vitro model of differentiating human lens epithelial cells (Blakely et al., Investigative Ophthalmology &Visual Sciences, 41(12):3898-3907, 2000). We have investigated radiation effects on several gene families that include, or relate to, DNA damage, cytokines, cell-cycle regulators, cell adhesion molecules, cell cytoskeletal function and apoptotic cell death. In this paper we will summarize some of our dose-dependent data from several radiation types, and describe the model of molecular and cellular events that we believe may be associated with precataractous events in the human lens after radiation exposure. This work was supported by NASA Grant #T-965W.

  10. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    Czech Academy of Sciences Publication Activity Database

    Konvalina, Ivo; Müllerová, Ilona

    2011-01-01

    Roč. 645, č. 1 (2011), s. 55-59 ISSN 0168-9002 R&D Projects: GA ČR GAP102/10/1410; GA AV ČR IAA100650902; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : cathode lens * compound objective lens * aberration coefficients * spot size * field calculations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.207, year: 2011

  11. Vitreous advanced glycation endproducts and alpha-dicarbonyls in retinal detachment patients with type 2 diabetes mellitus and non-diabetic controls

    NARCIS (Netherlands)

    Fokkens, Bernardina T.; Mulder, Douwe J.; Schalkwijk, Casper G.; Scheijen, Jean L.; Smit, Andries J.; Los, Leonoor I.

    2017-01-01

    Purpose Advanced glycation endproducts (AGEs) and their precursors alpha-dicarbonyls are implicated in the progression of diabetic retinopathy. The purpose of this study was to assess AGEs and a-dicarbonyls in the vitreous of patients with type 2 diabetes mellitus (T2DM) with early stages or absence

  12. Role of posterior vitreous detachment on outcome of anti-vascular endothelial growth factor treatment in age-related macular degeneration.

    Science.gov (United States)

    Üney, Güner Ö; Ünlü, Nurten; Acar, Mehmet A; Hazirolan, Dicle; Altiparmak, Uğur E; Yalniz-Akkaya, Zuleyha; Örnek, Firdevs

    2014-01-01

    The aim of this study was to determine the effect of posterior vitreous detachment on outcome of anti-vascular endothelial growth factor injection. Sixty-one eyes with age-related macular degeneration that had received intravitreal bevacizumab or ranibizumab injections were retrospectively reviewed. The vitreomacular interface was evaluated, and eyes were grouped according to the presence of posterior vitreous detachment (Group 1, n = 25) or vitreomacular adhesion (Group 2, n = 36). All patients received three loading doses of intravitreal anti-vascular endothelial growth factor injections at monthly intervals, and subsequently, pro re nata regimen was performed. Best-corrected visual acuity and central foveal thickness measurement at follow-up were evaluated. The development of posterior vitreous detachment during the follow-up was also reported. The best-corrected visual acuity changes at each visit compared with baseline were significantly better in Group 1 (P = 0.01, 0.02, 0.02, 0.009, 0.009, respectively at third, sixth, ninth, 12th month, and last visit). When best-corrected visual acuity was classified according to the change in visual acuity of 10 letters or more, the rate of improved or stable best-corrected visual acuity was greater in Group 1 (P = 0.02). During the follow-up, 5 eyes (14.3%) developed posterior vitreous detachment. Vitreomacular adhesion seems to have an adverse effect on the visual prognosis of anti-vascular endothelial growth factor treatment for age-related macular degeneration.

  13. In-situ integrity control of frozen-hydrated, vitreous lamellas prepared by the cryo-focused ion beam-scanning electron microscope.

    Science.gov (United States)

    de Winter, D A Matthijs; Mesman, Rob J; Hayles, Michael F; Schneijdenberg, Chris T W M; Mathisen, Cliff; Post, Jan A

    2013-07-01

    Recently a number of new approaches have been presented with the intention to produce electron beam transparent cryo-sections (lamellas in FIB-SEM terminology) from hydrated vitreously frozen cryo samples with a Focused Ion Beam (FIB) system, suitable for cryo-Transmission Electron Microscopy (cryo-TEM). As the workflow is still challenging and time consuming, it is important to be able to determine the integrity and suitability (cells vs. no cells; vitreous vs. crystalline) of the lamellas. Here we present an in situ method that tests both conditions by using the cryo-Scanning Electron Microscope (cryo-SEM) in transmission mode (TSEM; Transmission Scanning Electron Microscope) once the FIB-made lamella is ready. Cryo-TSEM imaging of unstained cells yields strong contrast, enabling direct imaging of material present in the lamellas. In addition, orientation contrast is shown to be suitable for distinguishing crystalline lamellas from vitreous lamellas. Tilting the stage a few degrees results in changes of contrast between ice grains as a function of the tilt angle, whereas the contrast of areas with vitreous ice remains unchanged as a function of the tilt angle. This orientation contrast has subsequently been validated by cryo-Electron BackScattered Diffraction (EBSD) in transmission mode. Integration of the presented method is discussed and the role it can play in future developments for a new and innovative all-in-one cryo-FIB-SEM life sciences instrument. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Prostaglandin E2 Levels of Aqueous and Vitreous Humor in Ketorolac 0.4% and Nepafenac 0.1% Administered Healthy Rabbits.

    Science.gov (United States)

    Acar, Ugur; Acar, Damla Erginturk; Tanriverdi, Cafer; Acar, Mutlu; Ozdemir, Ozdemir; Erikci, Acelya; Ornek, Firdevs

    2017-06-01

    To compare the lowering effects of ketorolac 0.4% and nepafenac 0.1% on aqueous and vitreous humor prostaglandin E 2 (PGE 2 ) levels in rabbits. Ketorolac and nepafenac ophthalmic solutions were administered to the right eyes of 24 healthy rabbits after randomized division into two groups. The left eyes of these rabbits were considered as controls for the two groups. On the 4th day of the experiment, the samples were taken from the aqueous and vitreous humors of the rabbits bilaterally, and PGE 2 levels were measured by an enzyme immune assay kit. Ketorolac and nepafenac achieved a statistically significant decrease (phumor (6.58 ± 4.62 and 9.83 ± 4.55 pg/mL, respectively). Both ketorolac and nepafenac inhibited PGE 2 levels in both the aqueous and vitreous humors of rabbits. Although PGE 2 -lowering effects were similar in the aqueous humor, nepafenac seemed to be more potent than ketorolac in the vitreous humor.

  15. Intrinsic lens potential of neural retina inhibited by Notch signaling as the cause of lens transdifferentiation.

    Science.gov (United States)

    Iida, Hideaki; Ishii, Yasuo; Kondoh, Hisato

    2017-01-15

    Embryonic neural retinas of avians produce lenses under spreading culture conditions. This phenomenon has been regarded as a paradigm of transdifferentiation due to the overt change in cell type. Here we elucidated the underlying mechanisms. Retina-to-lens transdifferentiation occurs in spreading cultures, suggesting that it is triggered by altered cell-cell interactions. Thus, we tested the involvement of Notch signaling based on its role in retinal neurogenesis. Starting from E8 retina, a small number of crystallin-expressing lens cells began to develop after 20 days in control spreading cultures. By contrast, addition of Notch signal inhibitors to cultures after day 2 strongly promoted lens development beginning at day 11, and a 10-fold increase in δ-crystallin expression level. After Notch signal inhibition, transcription factor genes that regulate the early stage of eye development, Prox1 and Pitx3, were sequentially activated. These observations indicate that the lens differentiation potential is intrinsic to the neural retina, and this potential is repressed by Notch signaling during normal embryogenesis. Therefore, Notch suppression leads to lens transdifferentiation by disinhibiting the neural retina-intrinsic program of lens development. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Pilot study of the dose in crystalline lens in the interventional radiology practice

    International Nuclear Information System (INIS)

    Castro, A.; Martinez, A.; Fernandez, A.; Molina, D.; Sanchez, L.; Diaz, A.

    2014-08-01

    The interventional radiology involves considerable exposure levels for the occupationally exposed personnel (OEP). The doses can encompass a wide range of values in dependence of the function that develops the personnel and the complexity of each procedure. In organs like the crystalline lens and skin values can be reached that imply the appearance of deterministic effects if is not fulfilled the appropriate measures of radiological protection. This has been demonstrated through multiple studies, among those that the retrospective study of damages in the crystalline lens and dose has been one of those most commented, known as RELID. The objective of that study was to examine the opacity prevalence in the crystalline lens in workers linked to the interventional cardiology and to correlate it with the occupational exposition. The obtained results contributed to that the ICRP recommend a new limit value of equivalent dose for crystalline lens of 20 mSv in one year. With the objective of analyzing the operational implications, in the radiological surveillance programs that they could originate with the new recommendations was developed a pilot study to evaluate the dose in crystalline lens in the OEP linked to the interventional radiology in a Cuban hospital. For this, an anthropomorphic mannequin RANDO-ALDERSON was used on which thermoluminescent dosimeters were placed below and above of the leaded apron and in different positions at level of the crystalline lens: above, below and to the sides of the leaded lenses that the personnel uses routinely. The mannequin was located on the same positions that occupy the main specialist that execute the procedure, as well as of the nurse to assist him. The measurements were made simulating the more representative procedures about complexity, duration time and exposure rate. The used dosimeters were RADOS model for whole body composed of two thermoluminescent detectors Gr-200 (LiF: Mg, Cu, P) to evaluate personal equivalent dose

  17. Nanosecond KTN varifocal lens without electric field induced phase transition

    Science.gov (United States)

    Zhu, Wenbin; Chao, Ju-Hung; Chen, Chang-Jiang; Campbell, Adrian; Henry, Michael; Yin, Stuart (Shizhuo); Hoffman, Robert C.

    2017-08-01

    This paper presents a nanosecond speed KTN varifocal lens. The tuning principle of varifocal lens is based on the high-speed refractive index modulation from the nanosecond speed tunable electric field. A response time on the order of nanoseconds was experimentally demonstrated, which is the fastest varifocal lens reported so far. The results confirmed that the tuning speed of the KTN varifocal lens could be significantly increased by avoiding the electric field induced phase transition. Such a nanosecond speed varifocal lens can be greatly beneficial for a variety of applications that demand high speed axial scanning, such as high-resolution 3D imaging and high-speed 3D printing.

  18. Elaboration of vitreous and vitrocrystalline basalt materials containing simulated radioactive ash wastes. Study of some physical properties and leaching behaviour

    International Nuclear Information System (INIS)

    Lebeau, M.J.

    1988-01-01

    This work is a preliminary study of a matrix for containment of incinerator ashes. Basalt presents a good capacity for ash incorporation (up to 50%), glasses obtained are homogeneous and the low viscosity at 1300 0 C allows an industrial preparation. Vitrocrystalline products have a dendritic texture which can be controlled by cooling rate and are composed of magnesioferrite, pyroxene, plagioclase and vitreous fraction depending on the filling material ratio. Uranium and thorium, for actinide simulation in ashes, are localized in the glass. Glass leaching decrease with ash content and the alteration film presents a better retention of some elements, such as uranium and thorium. Vitrocrystalline materials are less leachable than glasses. Interesting possibilities are shown for use of basalt as filling material in underground storage, since basalt decrease glass deterioration [fr

  19. Vitreous System Ag2O –ZnO–B2O3 Action Against Gram Negative Bacteria

    Directory of Open Access Journals (Sweden)

    Razvan Stefan

    2010-05-01

    Full Text Available In this work the ability of the system xAg2O  (100-x [45ZnO55B2O3] oxide glasses to inhibit the growth of bacteria Eschierchia coli, Pseudomonas and Salmonella was investigated. Using the diffusimetric method there were measured the diameters of inhibition, in order to classify the sensitivity of gram negative bacteria to oxide compounds containing silver, for their use as filters. Vitreous samples were processed as powders with grain between 45 and 75 m and less than 45 m for a large of contact area with the microorgansms and to make possible the study of biological effect of grain addiction. Action of the investigated oxide system against the gram negative bacteria is strictly related to the presence of silver oxide in glass composition.

  20. Embodied female experience through the lens of imagination.

    Science.gov (United States)

    Green, Sharon R

    2010-06-01

    In 1971, I made a film entitled Self Portrait of a Nude Model Turned Cinematographer in which I explore the objectifying 'male' gaze on my body in contrast to the subjective lived experience of my body. The film was a radical challenge to the gaze that objectifies woman - and thus imprisons her - which had hitherto dominated narrative cinema. Since the objectification of women has largely excluded us from the privileged phallogocentric discourses, in this paper I hope to bring into the psychoanalytic dialogue a woman's lived experience. I will approach this by exploring how remembering this film has become a personally transformative experience as I look back on it through the lens of postmodern and feminist discourses that have emerged since it was made. In addition, I will explore how this process of imaginatively looking back on an artistic creation to generate new discourses in the present is similar to the transformative process of analysis. Lastly, I will present a clinical example, where my embodied countertransference response to a patient's subjection to the objectifying male gaze opens space for a new discourse about her body to emerge.

  1. Use of intravitreal bevacizumab or triamcinolone acetonide as a preoperative adjunct to vitrectomy for vitreous haemorrhage in diabetics

    Directory of Open Access Journals (Sweden)

    Daniel Araújo Ferraz

    2013-02-01

    Full Text Available PURPOSE: To evaluate the effect of preoperative intravitreal bevacizumab (IVB or triamcinolone (IVT on the rate of early postvitrectomy hemorrhage in proliferative diabetic retinopathy (PDR. METHODS: Eligible eyes were assigned randomly to 1 of 3 groups: the IVB group received 1.25 mg bevacizumab, the IVT group received 4,0mg triamcinolone and the control group underwent a sham procedure. The primary outcome measure was the incidence of early postvitrectomy hemorrhage. Secondary outcome measures included changes in visual acuity (BCVA and adverse events. RESULTS: Twenty and seven eyes, 9 in each group were randomized. The incidence of vitreous hemorrhage was lower in the IVB group (p=0.18. Postoperative vitreous hemorrhage at 1 month also was less in the IVB group compared with the control group (p > 0.05. The rate of bleeding immediately after surgery was higher in IVT group with 4 (44.4% cases. The overall mean visual acuity was 1.72 ± 0.37 logMAR preoperatively and 1.32 ± 0.73 logMAR in 6 months after surgery. Accessing visual acuity by group evidenced that the IVB group had initial mean logMAR VA of 1.87 and 1.57 logMAR VA at the six months (p = 0.84. In IVT group, initial mean VA was 1.75 logMAR and 0.96 logMAR VA at six months (p < 0.001. And in control group, the initial mean VA was 1.85 logMAR and 1.57 logMAR VA at six months (p= 0.34. CONCLUSION: Intravitreal injection of bevacizumab 1 week before vitrectomy seems to reduce the incidence of early postvitrectomy hemorrhage in diabetic patients. There was a better visual acuity outcome in the triamcinolone group.

  2. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  3. Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

    Science.gov (United States)

    Chhabra, Mahendra

    The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

  4. Subjective assessment of contact lens wear by army aircrew.

    Science.gov (United States)

    Lattimore, M R; Cornum, R L

    1993-07-01

    Because 23% of Army aviators are ametropic, contact lenses have drawn increased attention as a spectacle substitute to solve system compatibility problems. From November 1988 until October 1991, a series of contact lens research protocols were conducted to develop a comprehensive database on contact lens wear in varied environments. Questionnaires were used to assess suitability and acceptability of routine contact lens wear. Responses from 202 subjects were obtained from September 1989 through September 1991. The questions explored operational and safety of flight issues of contact lens wear. Subjects overwhelmingly approved of contact lens use in all settings: 95% expressed greater combat readiness and effectiveness with contact lenses, 98% felt contact lens use (and maintenance) in the cockpit had no adverse impact on safety of flight, and 98% endorsed the routine use of contact lenses. These data highlight Army aircrew acceptance of contact lens use.

  5. Pars Plana Vitrectomy in Treatment of Lens Injury

    Directory of Open Access Journals (Sweden)

    Remzi Avcı

    2013-01-01

    Full Text Available Lens injury due to traumas may present as loss of capsule integrity, cataract, lens subluxation, or lens luxation. In addition, lens subluxation and lens luxation may occur in pseudophakic patients due to trauma. Clear corneal, scleral or sclero-corneal phacoemulsification surgery, pars plana vitrectomy, pars plana vitrectomy with phaco-fragmentation, or pars plana vitrectomy with removal through corneal incision techniques are used in the treatment of lens injury due to traumas. Intraocular lens can be implanted in the bag, sulcus, or anterior chamber during the surgery. Depending on the circumstances, scleral fixated intraocular lenses or iris-claw lenses may also be preferred. Rehabilitation of such patients is not of a great concern today, with the advanced level of vitreoretinal surgery and cataract surgery techniques and with the current state of technology. (Turk J Ophthalmol 2013; 43: 51-4

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

    Science.gov (United States)

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

    2012-06-01

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

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

    International Nuclear Information System (INIS)

    Mahmood, S.A.; Zafar, S.

    2014-01-01

    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)

  8. Evaluation of different surgical techniques in the management of subluxated cataractous lens.

    Science.gov (United States)

    Aldakaf, A; Bakir, H; Almogahed, A; Carstocea, Benone

    2007-01-01

    To compare and evaluate the outcome of different surgical techniques in the management of subluxated cataractous lens. This retrospective study included 18 eyes of 18 patients with subluxated cataracts of varying etiology. Their preoperative examination maintain included: best corrected visual acuity (BCVA), thorough anterior segment examination, by slit -lamp especially for the degree and extent of subluxation and cataract, cornea, iris and the pupil for other abnormalities or other traumatic signs, presence or absence of vitreous in the anterior chamber, IOP and finally fundus examination. The patients were then divided into 3 groups each comprising 6 patients. The first group underwent ECCE with sulcus implantation PMMA IOL , the second and third groups underwent phacoemulsification with bag implanted Acrylic IOL but the third group underwent special techniques and precautions during surgery. Postoperatively, all patients were examined for BCVA, IOP, IOL positioning, pupil, fundus examination. Thirteen patients were males and five were females. The etiology of subluxation was traumatic in ten males and two female. The ages of the patients were between 11 and 62 years old the post operative follow up period ranged between 7 and 16 months. No major intraoperative complications were noted. In the 1st group 2 patients underwent AC automated vitrectomy, 3 in the 2nd group, 1 in the 3rd group. Three patients needed scleral fixation suture . Thirteen patients had well centered IOL and 4 had slight decentration not necessitating further intervention and one in the 2nd group had clinically significant decentration where IOL explanation, widening of the wound and re implantation of a wide 6.5mm optic PMMA IOL was done in the second post operative daily. Subluxated cataracts need special precautions in the chosen surgical technique to maintain a reasonable safety level intraoperatively and an acceptable surgical.

  9. Application of capsular tension ring combined with iris hooks in phacoemulsification of traumatic cataract with lens subluxation

    Directory of Open Access Journals (Sweden)

    Li-Gang Li

    2015-07-01

    Full Text Available AIM: To evaluate the clinical efficacy and safety of capsular tension ring(CTRcombined with iris hooks in eyes with large traumatic zonular dialysis or weakness that underwent micro-incision coaxial phacoemulsification with posterior chamber(PCintraocular lens(IOLimplantation. METHODS: This prospective study was carried on 21 patients(21 eyeswith traumatic cataract and traumaticzonular dialysis(RESULTS: The mean follow-up period was 3~12mo. No serious postoperative complication was found. BCVA in our cases: 0.8 in 5 eyes. IOPs were in normal range too. The IOLs in 20 eyes remained the required position to the final follow-up examination except one eye in which the PC IOL was dislocated into vitreous cavity due to a postoperative spontaneity PCR, and in which vitrectomy and IOL suture fixation was performed.CONCLUSION: In cases of cataract associated with traumatic zonular dialysis(<180°, by setting the rational parameters of phacoemulsification, the CTR and iris hooks are found to be efficient in preventing IOL decentration and reducing operation complication. In our cases, the CTR combined with iris hooks is relatively safe application.

  10. Spontaneous dislocation of lens bag with acrylic lens after uneventful cataract surgery - unusual complication of cataract surgery.

    Science.gov (United States)

    Shah, Mehul A; Shah, Shreya M; Mehta, Ruchir; Shah, Prerna

    2015-01-01

    Spontaneous dislocation of intraocular lens with bag is rare. We report a case of a 56-year-old male who presented with spontaneous anterior dislocation of an in-the-bag intraocular lens 3 years after manual small incision cataract surgery. He had undergone manual small incision cataract surgery with foldable acrylic intraocular lens implantation, and 18 months after cataract surgery ND: YAG capsulotomy with uneventful post capsulotomy follow-up. 17 months after capsulotomy, the patient presented with sudden decrease of vision. On anterior segment examination, the intraocular lens with bag was dislocated into the anterior chamber. It was managed with intraocular lens explantation with bag, anterior vitrectomy and sclera fixated intraocular lens. Spontaneous intraocular lens dislocation with bag is possible after 1.5 years of uneventful surgery which may be managed using different techniques.

  11. Gravitational Lens Time Delays Using Polarization Monitoring

    Directory of Open Access Journals (Sweden)

    Andrew Biggs

    2017-11-01

    Full Text Available Gravitational lens time delays provide a means of measuring the expansion of the Universe at high redshift (and therefore in the ‘Hubble flow’ that is independent of local calibrations. It was hoped that many of the radio lenses found in the JVAS/CLASS survey would yield time delays as these were selected to have flat spectra and are dominated by multiple compact components. However, despite extensive monitoring with the Very Large Array (VLA, time delays have only been measured for three of these systems (out of 22. We have begun a programme to reanalyse the existing VLA monitoring data with the goal of producing light curves in polarized flux and polarization position angle, either to improve delay measurements or to find delays for new sources. Here, we present preliminary results on the lens system B1600+434 which demonstrate the presence of correlated and substantial polarization variability in each image.

  12. Complications caused by contact lens wearing.

    Science.gov (United States)

    Beljan, Jasna; Beljan, Kristina; Beljan, Zdravko

    2013-04-01

    Complications in wearing contact lenses are very rare and caused by poor maintenance, over-extended wear and wearing of contact lenses in a polluted environment. Regular control by a professional person can efficiently reduce the number of complications. This paper describes the most common risks factors for complications, and complications of wearing contact lenses with the classification according to the anatomic parts of the eye: eyelids, tear film, limbus, corneal epithelium, corneal stroma and corneal endothelium. Every complication has been described by the characteristic signs and symptoms, etiology and pathology, as well as therapy and prognosis. The paper describes how to select adequate customers as contact lens users, with proper education in order to ensure minimal incidence of complications due to contact lens wear, thus attracting a lot of satisfied and healthy customers.

  13. Effects of Temperature on Hybrid Lens Performance

    Science.gov (United States)

    Askins, Steve; Victoria, Marta; Herrero, Rebeca; Domínguez, César; Antón, Ignacio; Sala, Gabriel

    2011-12-01

    In hybrid Silicone-on-glass Fresnel lenses, an optical silicone is molded onto a glass substrate and forms the Fresnel structure. These lenses offer a cost effective solution as a primary optical element in point-focus concentrator photovoltaic modules, as well as performance advantages. However, these lenses have a high performance variation with temperature due both to the change in index of refraction of silicone as well as to deformations in the facets caused by coefficient of thermal expansion (CTE) mismatch. In this study we perform measurements of the light flux at the focal plane of a family of SOG lenses, varying temperature and lens-to-receiver distances. The effect of varying silicone cure temperature and the depth of the silicone between the lens and the glass substrate on temperature dependence was investigated. A preliminary computer model of this behavior is presented.

  14. A Tribute to Dr. Willy Lens

    Directory of Open Access Journals (Sweden)

    Maarten Vansteenkiste

    2016-07-01

    Full Text Available Dr. Willy Lens, born on December 10th, 1943, passed away on August 29th, 2014. With his passing, the motivation community has lost a seminal member, a mentor, and a friend. Dr. Lens – a Fellow of the Association for Psychological Science and Founding Fellow of the American Educational Research Association – made fundamental contributions to the study of motivation both through his own work and through his caring and thoughtful mentorship of a large community of scholars. With this tribute, we want to honor Dr. Willy Lens’ significance to psychology and education as well as his positive influence, both personally and professionally, on the lives of dozens of scholars. With his contagious enthusiasm and caring mentorship, Willy was an example for our academic community and with this tribute we express our gratitude for the privilege to have collaborated with him.

  15. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    Science.gov (United States)

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  16. Intraocular lens implantation in microphthalmic patients.

    Science.gov (United States)

    Sinskey, R M; Amin, P; Stoppel, J

    1992-09-01

    Microphthalmos is a developmental disorder of the eye consisting of a smaller than normal eye. This disorder can present as an isolated condition or associated with other systemic alterations. It is not uncommon for patients with microphthalmos to have congenital cataracts along with other ocular and systemic abnormalities. This paper reports the experience with 11 microphthalmic eyes of seven patients who had primary or secondary intraocular lens (IOL) implantation over a six-year period from 1985 to 1991. In all cases the IOL had a 13.5 mm or 14.0 mm overall diameter and a 6.0 mm or 6.5 mm optic. It was difficult to obtain documentation of objective visual improvement in many of these cases because of the associated nystagmus. However, all patients reported subjective improvements. These results suggest that with proper technique and lens selection microphthalmic patients should be considered for IOL implantation with relative safety and success.

  17. Pulser for the Tevatron electron lens gun

    Energy Technology Data Exchange (ETDEWEB)

    Iouri Terechkine et al.

    2004-05-18

    To compensate for beam-beam interaction in Tevatron, an ''electron lens'' is considered to be an effective instrument. When a bunch of electrons with energy in the range (10-16) kV is overlapping with a bunch of antiprotons, the resulting focusing force for antiprotons can be adjusted by changing the electron beam current and by profiling its radial distribution. There exist several scenarios of how the system must function. According to one of them, an electron gun that supplies electrons must be fed by voltage pulses that follow with the frequency of antiproton bunches circulating in the Tevatron, which is about 2.5 MHz. To provide focusing tailored for each individual antiproton bunch, a modulator of the gun (pulser) must allow pulse-to-pulse voltage change. This report will cover main approaches to a design of a pulser for use with the gun of the Tevatron Electron Lens.

  18. Sterilization potential of contact lens solutions

    OpenAIRE

    Dada Vijay; Mehta Manoj

    1988-01-01

    In a dynamic field of Contact Lens Solutions maintenance of high standards of anti-microbial activity is a must Resterilization Activity Time′ is a universally accepted yardstick for such an evaluation. In this study eight brands of indigenous popular solutions alongwith two FDA approved solutions were tested for their sterilization efficacy: Standardized suspensions of Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus fumigatus were used for the purpose. ...

  19. Performance of a Be Refractive Lens

    International Nuclear Information System (INIS)

    Smither, R.K.; Khounsary, A.M.; Mancini, D.C.; Saleem, K. Abu

    2004-01-01

    The performance of a beryllium compound refractive lens (CRL) was tested in the energy range of 11.5 to 8.0 keV. The beryllium refractive lens consists of 50 aligned, 1-mm-diameter, hollow spheres in a solid block of beryllium, 30 mm x 20 mm x 55 mm. The minimum web between each hollow sphere was 0.10 mm. The measured focal length of the lens for x-rays close to the axis of the beam was 147.7 cm +/- 2.0 cm at 10 keV and 120.2 +/- 2.0 cm at 9.1 keV. These values agree well with the theoretical values of 146.6 cm and 121.4 cm, respectively. The diameter of the best focus obtained at 10 keV was 35 μm horizontal and 45 μm vertical. For the modified version of the lens used in the 9.1 keV experiment these values were 25 μm horizontal and 35 μm vertical. The x-ray beam cross section for the 10 keV and the 9.1 keV experiments were 0.50 mm x 0.50 mm and 0.30 mm x 0.30 mm, respectively. The enhancement of the flux (photons per sq. mm) was 50:1 at 10 keV and 80:1 in the 9.1 keV experiment

  20. The radiodensity of cerebrospinal fluid and vitreous humor as indicator of the time since death

    NARCIS (Netherlands)

    Koopmanschap, D.H.; Bayat, A.R.; Kubat, B.; Bakker, H.M. de; Prokop, M.; Klein, W.M.

    2016-01-01

    PURPOSE: After death, a series of changes occur naturally in the human body in a fairly regular pattern. These postmortem changes are detectable on postmortem CT scans (PMCT) and may be useful in estimating the postmortem interval (PMI). The purpose of our study is to correlate the PMCT

  1. THE BOSS EMISSION-LINE LENS SURVEY. IV. SMOOTH LENS MODELS FOR THE BELLS GALLERY SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Yiping [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Bolton, Adam S.; Montero-Dorta, Antonio D.; Cornachione, Matthew A.; Zheng, Zheng; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Mao, Shude [Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084 (China); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Pérez-Fournon, Ismael; Marques-Chaves, Rui [Instituto de Astrofísica de Canarias, C/Vía Láctea, s/n, E-38205 San Cristóbal de La Laguna, Tenerife (Spain); Oguri, Masamune [Research Center for the Early Universe, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ménard, Brice, E-mail: yiping.shu@nao.cas.cn [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2016-12-20

    We present Hubble Space Telescope F606W-band imaging observations of 21 galaxy-Ly α emitter lens candidates in the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey (BELLS) for the GALaxy-Ly α EmitteR sYstems (BELLS GALLERY) survey. Seventeen systems are confirmed to be definite lenses with unambiguous evidence of multiple imaging. The lenses are primarily massive early-type galaxies (ETGs) at redshifts of approximately 0.55, while the lensed sources are Ly α emitters (LAEs) at redshifts from two to three. Although most of the lens systems are well fit by smooth lens models consisting of singular isothermal ellipsoids in an external shear field, a thorough exploration of dark substructures in the lens galaxies is required. The Einstein radii of the BELLS GALLERY lenses are, on average, 60% larger than those of the BELLS lenses because of the much higher source redshifts. This will allow for a detailed investigation of the radius evolution of the mass profile in ETGs. With the aid of the average ∼13× lensing magnification, the LAEs are frequently resolved into individual star-forming knots with a wide range of properties. They have characteristic sizes from less than 100 pc to several kiloparsecs, rest-frame far-UV apparent AB magnitudes from 29.6 to 24.2, and typical projected separations of 500 pc to 2 kpc.

  2. [Congenital lens subluxation: visual acuity outcomes and intraocular lens postoperative position].

    Science.gov (United States)

    Arraes, Caroline; Endriss, Daniela; Lobato, Francisco; Arraes, João; Ventura, Marcelo

    2010-01-01

    To evaluate the visual acuity outcomes and to investigate the intraocular lens (IOL) and endocapsular ring positions with ultrasound biomicroscopy in 17 eyes of 10 patients with congenital lens subluxation who underwent the same surgical technique, by the same surgeon. The study was performed in the ''Hospital de Olhos de Pernambuco'' and ''Fundação Altino Ventura''. The surgical technique consisted of phacoaspiration with implant of endocapsular ring and intraocular lens with one loop haptic amputated. The age varied from 7 to 22 years. Data on visual acuity (VA) before and after surgery, surgery follow-up period, and complications were analyzed. All patients underwent ultrasound biomicroscopy. The mean follow-up period was 2.8 years. There was a VA improvement in 17 (100%) eyes: in 12 eyes (70.6%) the visual acuity was better than 20/40; 4 (23.5%) ranged from 20/40 to 20/100, and 1 (5.9%) had visual acuity worse than 20/100, however better than the preoperative visual acuity. The posterior capsular opacification occurred in 10 eyes (58.9%). Ultrasound biomicroscopy showed that all IOL were partially decentralized, however without surpassing the pupil border limit. Endocapsular ring position was correct and there was a good capsular support in all cases. The evaluated surgical treatment provided good intraocular lens and endocapsular ring position, with VA improvement Thus, this technique is a viable, effective and safe option for the visual rehabilitation of patients with congenital lens subluxation.

  3. Non-Invasive Early Detection and Molecular Analysis of Low X-ray Dose Effects in the Lens

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, Lee [Boston University

    2014-07-02

    This is the Final Progress Report for DOE-funded research project DE-PS02-08ER08-01 titled “Non-Invasive Early Detection and Molecular Analysis of Low X-ray Dose Effects in the Lens”. The project focuses on the effects of low-linear energy transfer (LET) radiation on the ocular lens. The lens is an exquisitely radiosensitive tissue with a highly-ordered molecular structure that is amenable to non-invasive optical study from the periphery. These merits point to the lens as an ideal target for laser-based molecular biodosimetry (MBD). Following exposure to different types of ionizing radiations, the lens demonstrates molecular changes (e.g., oxidation, racemization, crosslinkage, truncation, aggregation, etc.) that impact the structure and function of the long-lived proteins in the cytosol of lens fiber cells. The vast majority of proteins in the lens comprise the highly-ordered crystallins. These highly conserved lens proteins are amongst the most concentrated and stable in the body. Once synthesized, the crystallins are retained in the fiber cell cytoplasm for life. Taken together, these properties point to the lens as an ideal system for quantitative in vivo MBD assessment using quasi-elastic light scattering (QLS) analysis. In this project, we deploy a purpose-designed non-invasive infrared laser QLS instrument as a quantitative tool for longitudinal assessment of pre-cataractous molecular changes in the lenses of living mice exposed to low-dose low-LET radiation compared to non-irradiated sham controls. We hypothesize that radiation exposure will induce dose-dependent changes in the molecular structure of matrix proteins in the lens. Mechanistic assays to ascertain radiation-induced molecular changes in the lens focus on protein aggregation and gene/protein expression patterns. We anticipate that this study will contribute to our understanding of early molecular changes associated with radiation-induced tissue pathology. This study also affords potential for

  4. Two families of astrophysical diverging lens models

    Science.gov (United States)

    Er, Xinzhong; Rogers, Adam

    2018-03-01

    In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in the opposite sense to gravitational lensing, and is also of astrophysical interest. In fact, diverging lensing due to compact distributions of plasma has been proposed as an explanation for the extreme scattering events that produce frequency-dependent dimming of extragalactic radio sources, and may also be related to the refractive radio wave phenomena observed to affect the flux density of pulsars. In this work we study the behaviour of two families of astrophysical diverging lenses in the geometric optics limit, the power law, and the exponential plasma lenses. Generally, the members of these model families show distinct behaviour in terms of image formation and magnification, however the inclusion of a finite core for certain power-law lenses can produce a caustic and critical curve morphology that is similar to the well-studied Gaussian plasma lens. Both model families can produce dual radial critical curves, a novel distinction from the tangential distortion usually produced by gravitational (converging) lenses. The deflection angle and magnification of a plasma lens vary with the observational frequency, producing wavelength-dependent magnifications that alter the amplitudes and the shape of the light curves. Thus, multiwavelength observations can be used to physically constrain the distribution of the electron density in such lenses.

  5. Dynamic metasurface lens based on MEMS technology

    Directory of Open Access Journals (Sweden)

    Tapashree Roy

    2018-02-01

    Full Text Available In the recent years, metasurfaces, being flat and lightweight, have been designed to replace bulky optical components with various functions. We demonstrate a monolithic Micro-Electro-Mechanical System (MEMS integrated with a metasurface-based flat lens that focuses light in the mid-infrared spectrum. A two-dimensional scanning MEMS platform controls the angle of the lens along two orthogonal axes by ±9°, thus enabling dynamic beam steering. The device could be used to compensate for off-axis incident light and thus correct for aberrations such as coma. We show that for low angular displacements, the integrated lens-on-MEMS system does not affect the mechanical performance of the MEMS actuators and preserves the focused beam profile as well as the measured full width at half maximum. We envision a new class of flat optical devices with active control provided by the combination of metasurfaces and MEMS for a wide range of applications, such as miniaturized MEMS-based microscope systems, LIDAR scanners, and projection systems.

  6. Adaptive Liquid Lens Actuated by Droplet Movement

    Directory of Open Access Journals (Sweden)

    Chao Liu

    2014-08-01

    Full Text Available In this paper we report an adaptive liquid lens actuated by droplet movement. Four rectangular PMMA (Polymethyl Methacrylate substrates are stacked to form the device structure. Two ITO (Indium Tin Oxide sheets stick on the bottom substrate. One PMMA sheet with a light hole is inserted in the middle of the device. A conductive droplet is placed on the substrate and touches the PMMA sheet to form a small closed reservoir. The reservoir is filled with another immiscible non-conductive liquid. The non-conductive liquid can form a smooth concave interface with the light hole. When the device is applied with voltage, the droplet stretches towards the reservoir. The volume of the reservoir reduces, changing the curvature of the interface. The device can thus achieve the function of an adaptive lens. Our experiments show that the focal length can be varied from −10 to −159 mm as the applied voltage changes from 0 to 65 V. The response time of the liquid lens is ~75 ms. The proposed device has potential applications in many fields such as information displays, imaging systems, and laser scanning systems.

  7. Thin wetting film lens-less imaging

    International Nuclear Information System (INIS)

    Allier, C.P.; Poher, V.; Coutard, J.G.; Hiernard, G.; Dinten, J.M.

    2011-01-01

    Lens-less imaging has recently attracted a lot of attention as a compact, easy-to-use method to image or detect biological objects like cells, but failed at detecting micron size objects like bacteria that often do not scatter enough light. In order to detect single bacterium, we have developed a method based on a thin wetting film that produces a micro-lens effect. Compared with previously reported results, a large improvement in signal to noise ratio is obtained due to the presence of a micro-lens on top of each bacterium. In these conditions, standard CMOS sensors are able to detect single bacterium, e.g. E. coli, Bacillus subtilis and Bacillus thuringiensis, with a large signal to noise ratio. This paper presents our sensor optimization to enhance the SNR; improve the detection of sub-micron objects; and increase the imaging FOV, from 4.3 mm 2 to 12 mm 2 to 24 mm 2 , which allows the detection of bacteria contained in 0.5 μl to 4 μl to 10 μl, respectively. (authors)

  8. Compound refractive X-ray lens

    International Nuclear Information System (INIS)

    Nygren, D.R.; Cahn, R.; Cederstrom, B.; Danielsson, M.; Vestlund, J.

    2000-01-01

    An apparatus and method are disclosed for focusing X-rays. In one embodiment, his invention is a commercial-grade compound refractive X-ray lens. The commercial-grade compound refractive X-ray lens includes a volume of low-Z material. The volume of low-Z material has a first surface which is adapted to receive X-rays of commercially-applicable power emitted from a commercial-grade X-ray source. The volume of low-Z material also has a second surface from which emerge the X-rays of commercially-applicable power which were received at the first surface. Additionally, the commercial-grade compound refractive X-ray lens includes a plurality of openings which are disposed between the first surface and the second surface. The plurality of openings are oriented such that the X-rays of commercially-applicable power which are received at the first surface, pass through the volume of low-Z material and through the plurality openings. In so doing, the X-rays which emerge from the second surface are refracted to a focal point

  9. Laboratory Demonstration of Axicon-Lens Coronagraph

    Science.gov (United States)

    Choi, Jaeho; Jea, Geonho

    2018-01-01

    The results of laboratory based experiments of the proposed coronagraph using axicon-lenses that is conjunction with a method of noninterferometric quantitative phase imaging for direct imaging of exoplanets is will present. The light source is passing through tiny holes drilled on the thin metal plate is used as the simulated stellar and its companions. Those diffracted light at the edge of the holes bears a similarity to the light from the bright stellar. Those images are evaginated about the optical axis after the maximum focal length of the first axicon lens. Then the evaginated images of have cut off using the motorized iris which means the suppressed the central stellar light preferentially. Various length between the holes which represent the angular distance are examined. The laboratory experimental results are shown that the axicon-lens coronagraph has feature of ability to achieve the smaller IWA than l/D and high-contrast direct imaging. The laboratory based axicon-lens coronagraph imaging support the symbolic computation results which has potential in direct imaging for finding exoplanet and various astrophysical activities. The setup of the coronagraph is simple to build and is durable to operate. Moreover it can be transported the planets images to a broadband spectrometric instrument that able to investigate the constituent of the planetary system.

  10. Metasurface axicon lens design at visible wavelengths

    Science.gov (United States)

    Alyammahi, Saleimah; Zhan, Qiwen

    2017-08-01

    The emerging field of metasurfaces is promising to realize novel optical devices with miniaturized flat format and added functionalities. Metasurfaces have been demonstrated to exhibit full control of amplitude, phase and polarization of electromagnetic waves. Using the metasurface, the wavefront of light can be manipulated permitting new functionalities such as focusing and steering of the beams and imaging. One optical component which can be designed using metasurfaces is the axicon. Axicons are conical lenses used to convert Gaussian beams into nondiffraction Bessel beams. These unique devices are utilized in different applications ranging from optical trapping and manipulation, medical imaging, and surgery. In this work, we study axicon lens design comprising of planar metasurfaces which generate non-diffracting Bessel beams at visible wavelengths. Dielectric metasurfaces have been used to achieve high efficiency and low optical loss. We measured the spot size of the resulted beams at different planes to demonstrate the non-diffraction properties of the resulted beams. We also investigated how the spot size is influenced by the axicon aperture. Furthermore, we examined the achromatic properties of the designed axicon. Comparing with the conventional lens, the metasurface axicon lens design enables the creation of flat optical device with wide range of depth of focus along its optical axis.

  11. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

    Baun, Christina; Falch Braas, Kirsten; D. Nielsen, Kamilla

    2015-01-01

    Radiation Dose to the Eye Lens: Does Positioning Really Matter? C. Baun1, K. Falch1, K.D. Nielsen2, S. Shanmuganathan1, O. Gerke1, P.F. Høilund-Carlsen1 1Department of Nuclear Medicine, Odense University Hospital, Odense C, Denmark. 2University College Lillebaelt, Odense, Denmark. Aim: The scan...... field in oncology patients undergoing eyes-to-thighs PET/CT must always include the base of the scull according to department guidelines. The eye lens is sensitive to radiation exposure and if possible it should be avoided to scan the eye. If the patient’s head is kipped backwards during the scan one...... might avoid including the eye in the CT scan without losing sufficient visualization of the scull base. The aim of this study was to evaluate the possibility of decreasing the radiation dose to the eye lens, simply by changing the head position, when doing the PET/CT scan from the base of the scull...

  12. Dynamic metasurface lens based on MEMS technology

    Science.gov (United States)

    Roy, Tapashree; Zhang, Shuyan; Jung, Il Woong; Troccoli, Mariano; Capasso, Federico; Lopez, Daniel

    2018-02-01

    In the recent years, metasurfaces, being flat and lightweight, have been designed to replace bulky optical components with various functions. We demonstrate a monolithic Micro-Electro-Mechanical System (MEMS) integrated with a metasurface-based flat lens that focuses light in the mid-infrared spectrum. A two-dimensional scanning MEMS platform controls the angle of the lens along two orthogonal axes by ±9°, thus enabling dynamic beam steering. The device could be used to compensate for off-axis incident light and thus correct for aberrations such as coma. We show that for low angular displacements, the integrated lens-on-MEMS system does not affect the mechanical performance of the MEMS actuators and preserves the focused beam profile as well as the measured full width at half maximum. We envision a new class of flat optical devices with active control provided by the combination of metasurfaces and MEMS for a wide range of applications, such as miniaturized MEMS-based microscope systems, LIDAR scanners, and projection systems.

  13. Radiation dose to the lens and cataract formation

    International Nuclear Information System (INIS)

    Henk, J.M.; Whitelocke, R.A.F.; Warrington, A.P.; Bessell, E.M.

    1993-01-01

    The purpose of this work was to determine the radiation tolerance of the lens of the eye and the incidence of radiation-induced lens changes in patients treated by fractionated supervoltage radiation therapy for orbital tumors. Forty patients treated for orbital lymphoma and pseudotumor with tumor doses of 20--40 Gy were studied. The lens was partly shielded using lead cylinders in most cases. The dose to the germinative zone of the lens was estimated by measurements in a tissue equivalent phantom using both film densitometry and thermoluminescent dosimetry. Opthalmological examination was performed at 6 monthly intervals after treatment. The lead shield was found to reduce the dose to the germinative zone of the lens to between 36--50% of the tumor dose for Cobalt beam therapy, and to between 11--18% for 5 MeV x-rays. Consequently, the lens doses were in the range 4.5--30 Gy in 10--20 fractions. Lens opacities first appeared from between 3 and 9 years after irradiation. Impairment of visual acuity ensued in 74% of the patients who developed lens opacities. The incidence of lens changes was strongly dose-related. None was seen after doses of 5 Gy or lower, whereas doses of 16.5 Gy or higher were all followed by lens opacities which impaired visual acuity. The largest number of patients received a maximum lens dose of 15 Gy; in this group the actuarial incidence of lens opacities at 8 years was 57% with visual impairment in 38%. The adult lens can tolerate a total dose of 5 Gy during a fractionated course of supervoltage radiation therapy without showing any changes. Doses of 16.5 Gy or higher will almost invariably lead to visual impairment. The dose which causes a 50% probability of visual impairment is approximately 15 Gy. 10 refs., 4 figs., 1 tab

  14. Clinical Presentation and Microbial Analyses of Contact Lens Keratitis; an Epidemiologic Study.

    Science.gov (United States)

    Rasoulinejad, Seyed Ahmad; Sadeghi, Mahmoud; Montazeri, Mohammad; Hedayati Goudarzi, Hesam; Montazeri, Mahmood; Akbarian, Nadali

    2014-01-01

    Microbial keratitis is an infective process of the cornea with a potentially and serious visual impairments. Contact lenses are a major cause of microbial keratitis in the developed countries especially among young people. Therefore, the purpose of the present study was to evaluate the frequency and microbiological characteristic of CLK in patients referred to the emergency department (ED) of teaching hospitals, Babol, Iran. This is a cross-sectional study of all patients with contact lens induced corneal ulcers admitted to the teaching hospitals of Babol, Iran, from 2011- 2013. An ophthalmologist examined patients with the slit-lamp and clinical features of them were noted (including pain, redness, foreign body sensation, chemosis, epiphora, blurred vision, discomfort, photophobia, discharge, ocular redness and swelling). All suspected infectious corneal ulcers were scraped for microbial culture and two slides were prepared. Data were analyzed using SPSS software, version 18.0. A total of 14 patients (17 eyes) were recruited into the study (100% female). The patients' age ranged from 16-37 years old (mean age 21.58±7.23 years). The most prevalent observed clinical signs were pain and redness. Three samples reported as sterile. The most common isolated causative organism was pseudomonas aeroginosa (78.6%), Staphylococcus aureus 14.3%, and enterobacter 7.1%, respectively. Treatment outcome was excellent in 23.5%, good in 47.1%, and poor in 29.4% of cases. Improper lens wear and care as well as the lack of awareness about the importance of aftercare visits have been identified as potential risk factors for the corneal ulcer among contact lens wearers. Training and increasing the awareness of adequate lens care and disinfection practices, consulting with an ophthalmologist, and frequent replacement of contact lens storage cases would greatly help reducing the risk of microbial keratitis.

  15. Better Visual Outcome by Intraocular Lens Ejection in Geriatric Patients with Ruptured Ocular Injuries

    Science.gov (United States)

    Sugita, Tadasu; Tsunekawa, Taichi; Matsuura, Toshiyuki; Takayama, Kei; Yamamoto, Kentaro; Kachi, Shu; Ito, Yasuki; Ueno, Shinji; Nonobe, Norie; Kataoka, Keiko; Suzumura, Ayana; Iwase, Takeshi; Terasaki, Hiroko

    2017-01-01

    Ocular trauma is one of the leading causes of visual impairment worldwide. Because of the popularity of cataract surgeries, aged individuals with ocular trauma commonly have a surgical wound in their eyes. The purpose of this study was to evaluate the visual outcome of cases that were coincident with intraocular lens (IOL) ejection in the eyes with ruptured open-globe ocular injuries. Consecutive patients with open-globe ocular injuries were first reviewed. Patients’ characteristics, corrected distance visual acuities (CDVAs) over 3 years after the trauma, causes of injuries, traumatic wound patterns, and coexistence of retinal detachment were examined. The relationships between poor CDVA and the other factors, including the complications of crystalline lens and IOL ejection, were examined. A total of 105 eyes/patients [43 eyes with rupture, 33 with penetrating, 28 with intraocular foreign body (IOFB), and 1 with perforating injuries] were included. Rupture injuries were common in aged patients and were mostly caused by falls, whereas penetrating and IOFB injuries were common in young male patients. CDVAs of the eyes with rupture injuries were significantly worse than those of the eyes with penetrating or IOFB injuries. CDVA from more than 50% of the ruptured eyes resulted in no light perception or light perception to 20/500. CDVA of the ruptured eyes complicated by crystalline lens ejection was significantly worse than that of those complicated by IOL ejection. The wounds of the ruptured eyes complicated by IOL ejection were mainly located at the superior corneoscleral limbus, whereas those of the eyes complicated by crystalline lens ejection were located at the posterior sclera. There were significant correlations between poor CDVA and retinal detachment and crystalline lens ejection. These results proposed a new trend in the ocular injuries that commonly occur in aged patients; history of cataract surgery might affect the final visual outcome after open

  16. Better Visual Outcome by Intraocular Lens Ejection in Geriatric Patients with Ruptured Ocular Injuries.

    Directory of Open Access Journals (Sweden)

    Hiroki Kaneko

    Full Text Available Ocular trauma is one of the leading causes of visual impairment worldwide. Because of the popularity of cataract surgeries, aged individuals with ocular trauma commonly have a surgical wound in their eyes. The purpose of this study was to evaluate the visual outcome of cases that were coincident with intraocular lens (IOL ejection in the eyes with ruptured open-globe ocular injuries. Consecutive patients with open-globe ocular injuries were first reviewed. Patients' characteristics, corrected distance visual acuities (CDVAs over 3 years after the trauma, causes of injuries, traumatic wound patterns, and coexistence of retinal detachment were examined. The relationships between poor CDVA and the other factors, including the complications of crystalline lens and IOL ejection, were examined. A total of 105 eyes/patients [43 eyes with rupture, 33 with penetrating, 28 with intraocular foreign body (IOFB, and 1 with perforating injuries] were included. Rupture injuries were common in aged patients and were mostly caused by falls, whereas penetrating and IOFB injuries were common in young male patients. CDVAs of the eyes with rupture injuries were significantly worse than those of the eyes with penetrating or IOFB injuries. CDVA from more than 50% of the ruptured eyes resulted in no light perception or light perception to 20/500. CDVA of the ruptured eyes complicated by crystalline lens ejection was significantly worse than that of those complicated by IOL ejection. The wounds of the ruptured eyes complicated by IOL ejection were mainly located at the superior corneoscleral limbus, whereas those of the eyes complicated by crystalline lens ejection were located at the posterior sclera. There were significant correlations between poor CDVA and retinal detachment and crystalline lens ejection. These results proposed a new trend in the ocular injuries that commonly occur in aged patients; history of cataract surgery might affect the final visual outcome

  17. Clinical Presentation and Microbial Analyses of Contact Lens Keratitis; an Epidemiologic Study

    Directory of Open Access Journals (Sweden)

    Seyed Ahmad Rasoulinejad

    2014-09-01

    Full Text Available Introduction: Microbial keratitis is an infective process of the cornea with a potentially and serious visual impairments. Contact lenses are a major cause of microbial keratitis in the developed countries especially among young people. Therefore, the purpose of the present study was to evaluate the frequency and microbiological characteristic of CLK in patients referred to the emergency department (ED of teaching hospitals, Babol, Iran. Methods: This is a cross-sectional study of all patients with contact lens induced corneal ulcers admitted to the teaching hospitals of Babol, Iran, from 2011- 2013. An ophthalmologist examined patients with the slit-lamp and clinical features of them were noted (including pain, redness, foreign body sensation, chemosis, epiphora, blurred vision, discomfort, photophobia, discharge, ocular redness and swelling. All suspected infectious corneal ulcers were scraped for microbial culture and two slides were prepared. Data were analyzed using SPSS software, version 18.0. Results: A total of 14 patients (17 eyes were recruited into the study (100% female. The patients’ age ranged from 16-37 years old (mean age 21.58±7.23 years. The most prevalent observed clinical signs were pain and redness. Three samples reported as sterile. The most common isolated causative organism was pseudomonas aeroginosa (78.6%, Staphylococcus aureus 14.3%, and enterobacter 7.1%, respectively. Treatment outcome was excellent in 23.5%, good in 47.1%, and poor in 29.4% of cases. Conclusion: Improper lens wear and care as well as the lack of awareness about the importance of aftercare visits have been identified as potential risk factors for the corneal ulcer among contact lens wearers. Training and increasing the awareness of adequate lens care and disinfection practices, consulting with an ophthalmologist, and frequent replacement of contact lens storage cases would greatly help reducing the risk of microbial keratitis.

  18. Phacoaspiration with a Cionni ring versus pars plana lensectomy, vitrectomy and sutureless transscleral IOL fixation in pediatric patients with a subluxated lens.

    Science.gov (United States)

    Thapa, Bikram Bahadur; Agarwal, Aniruddha; Singh, Ramandeep; Gupta, Parul Chawla; Ram, Jagat

    2016-05-01

    To compare outcomes of phacoaspiration (PA) with Cionni ring-assisted posterior-chamber intraocular lens implantation (PCIOL) versus pars plana lensectomy (PPL) with anterior vitrectomy (AV) and sutureless transscleral fixation of the IOL (TSFIOL) assisted with fibrin glue in the management of a subluxated lens. In this prospective and comparative interventional study, one eye of children with a bilateral subluxated lens was randomized to undergo PA with PCIOL using a Cionni ring (group A: n = 14 eyes), and the other eye underwent PPL + AV with glue-assisted TSFIOL (group B: n = 14 eyes). The outcome measures included best-corrected visual acuity (BCVA) in logMAR units and rates of complications at 12-month follow-up visits. 28 eyes of 14 children (age: 8.06 ± 4.49 years) were included in the study. BCVA improved from preoperative value of 1.21 to 0.4 (p = 0.001) in group A and from 1.53 to 0.31 (p = 0.001) in group B at month 12. There was no significant difference in the BCVA on comparing the two groups at month 12 (p > 0.411). Postoperative complications in group A included corneal edema (two eyes), Cionni hook capture (one eye), elevated IOP (one eye), and posterior capsular opacification (five eyes). In group B, corneal edema was seen in two eyes, hypotony in one eye, vitreous hemorrhage in one eye and pupillary optic capture in four eyes. Head-to-head comparison of the two techniques demonstrates no significant difference in the rates of complications at month 12. The decision to choose either technique may be based on the operating surgeon's skill, experience and preference.

  19. Novel Scanning Lens Instrument for Evaluating Fresnel Lens Performance: Equipment Development and Initial Results (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, R.; Miller, D. C.; Kurtz, S. R.; Anton, I.; Sala, G.

    2013-07-01

    A system dedicated to the optical transmittance characterization of Fresnel lenses has been developed at NREL, in collaboration with the UPM. The system quantifies the optical efficiency of the lens by generating a performance map. The shape of the focused spot may also be analyzed to understand change in the lens performance. The primary instrument components (lasers and CCD detector) have been characterized to confirm their capability for performing optical transmittance measurements. Measurements performed on SoG and PMMA lenses subject to a variety of indoor conditions (e.g., UV and damp heat) identified differences in the optical efficiency of the evaluated lenses, demonstrating the ability of the Scanning Lens Instrument (SLI) to distinguish between the aged lenses.

  20. A high excitation magnetic quadrupole lens quadruplet incorporating a single octupole lens for a low spherical aberration probe forming lens system

    Science.gov (United States)

    Dou, Yanxin; Jamieson, David N.; Liu, Jianli; Li, Liyi

    2018-03-01

    This paper describes the design of a new probe forming lens system consisting of a high excitation magnetic quadrupole lens quadruplet that incorporates a single magnetic octupole lens. This system achieves both a high demagnification and a low spherical aberration compared to conventional high excitation systems and is intended for deployment for the Harbin 300 MeV proton microprobe for applications in space science and ion beam therapy. This relative simplicity of the ion optical design to include a single octupole lens minimizes the risks associated with the constructional and operational precision usually needed for the probe forming lens system and this system could also be deployed in microprobe systems that operate with less magnetically rigid ions. The design of the new system is validated with reference to two independent ion optical computer codes.

  1. The neutron silicon lens. An update of the thermal neutron lens results

    International Nuclear Information System (INIS)

    Johnson, M.W.; Daymond, M.R.

    2001-01-01

    This paper introduces the concept of the Neutron Silicon Lens (NSL) and provides and update on the experimental results achieved to date. The NSL design is a cylindrical neutron lens based on the use of multiple neutron mirrors supported and separated by silicon wafers. Such lenses would have many applications in both the primary and scattered beams on neutron instruments, and would lead to immediate improvements where the sample to be illuminated is small, as in high pressure or engineering strain scanning instruments. (author)

  2. Lens regeneration in mice under the influence of vitamin A

    Indian Academy of Sciences (India)

    The effect of vitamin A has been studied on lens regeneration in young (7 days old) as well as adult mice. A longitudinal slit was made under local anesthesia in the cornea over the lens. The lens was extracted intact through the incision. Intraperitonial injection of vitamin A (0.05 ml of 30 IU/ml in young and 0.05 ml of 50 ...

  3. Subcontact Lens Bubble Formation under Low Atmospheric Pressure Conditions.

    Science.gov (United States)

    1986-08-01

    of subcontact lens bubble formation under scleral lenses at altitudes greater than 18,000 ft. Later, after many advances in contact lens fitting and...Reported here are the results of contact lens bubble studies with soft hydrophilic nd rigid gas-permeable lenses . Testing was accomplished in simulated...ccurred at altitudes greater than 20,000 ft. For soft contact lenses , bubble formation was etected in 22 of 92 eyes tested, and occurred at altitudes

  4. Analysis of phakic before intraocular lens implantation for fundus examination

    OpenAIRE

    Juan Chen; Zhong-Ping Chen; Rui-Ling Zhu

    2014-01-01

    AIM:To investigate the findings of the eyes which were examined preoperatively by three mirror contact lens before the implantation of implantable collamer lens(ICL). To analysis the retinal pathological changes and to explore the clinical analysis of early diagnosis and treatment in retinopathy on fundus examination before operation. METHODS:The retrospective case series study included 127 eyes of 64 patients who underwent phakic intraocular lens implantation were received the fundus examina...

  5. Haemophilus influenzae corneal ulcer in a therapeutic contact lens wearer.

    OpenAIRE

    Armstrong, J. R.; Cohen, K. L.; McCarthy, L. R.

    1984-01-01

    Haemophilus influenzae is an unusual corneal pathogen and an unusual cause of corneal ulcers in Western society. In previous reports corneal complications from H. influenzae have been secondary to a conjunctivitis. The first case of a primary H. influenzae corneal ulcer as a complication of therapeutic contact lens wear is presented. Since other uncommon bacteria have been reported as causes of contact lens related corneal ulcers, the bacteriology of contact lens related corneal ulcers is rev...

  6. Structural and surface functionality changes in reticulated vitreous carbon produced from poly(furfuryl alcohol) with sodium hydroxide additions

    Energy Technology Data Exchange (ETDEWEB)

    Oishi, Silvia Sizuka, E-mail: silviaoishi@uol.com.br [LAS, Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas 1758, São José dos Campos, SP 12227-010 (Brazil); Botelho, Edson Cocchieri [Departamento de Materiais e Tecnologia, Univ Estadual Paulista (UNESP), Av. Doutor Ariberto Pereira da Cunha 333, Guaratinguetá, SP 12516-410 (Brazil); Rezende, Mirabel Cerqueira [Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo (UNIFESP), Rua Talim 330, São José dos Campos, SP 12231-280 (Brazil); Ferreira, Neidenêi Gomes [LAS, Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas 1758, São José dos Campos, SP 12227-010 (Brazil)

    2017-02-01

    Highlights: • Reticulated vitreous carbon (RVC) was processed from poly(furfuryl alcohol) with different amounts of NaOH. • A correlation between microstructure and surface functionalities was proposed. • The structural ordering was mainly influenced by the cured PFA polymerization degree and carboxylic acid content on RVC surface. - Abstract: The use of sodium hydroxide to neutralize the acid catalyst increases the storage life of poly(furfuryl alcohol) (PFA) resin avoiding its continuous polymerization. In this work, a concentrated sodium hydroxide solution (NaOH) was added directly to the PFA resin in order to minimize the production of wastes generated when PFA is washed with diluted basic solution. Thus, different amounts of this concentrated basic solution were added to the resin up to reaching pH values of around 3, 5, 7, and 9. From these four types of modified PFA two sample sets of reticulated vitreous carbon (RVC) were processed and heat treated at two different temperatures (1000 and 1700 °C). A correlation among cross-link density of PFA and RVC morphology, structural ordering and surface functionalities was systematically studied using Fourier transform infrared spectroscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. The PFA neutralization (pH 7) led to its higher polymerization degree, promoting a crystallinity decrease on RVC treated at 1000 °C as well as its highest percentages of carboxylic groups on surface. A NaOH excess (pH 9) substantially increased the RVC oxygen content, but its crystallinity remained similar to those for samples from pH 3 and 5 treated at 1000 °C, probably due to the reduced presence of carboxylic group and the lower polymerization degree of its cured resin. Samples with pH 3 and 5 heat treated at 1000 and 1700 °C can be considered the most ordered which indicated that small quantities of NaOH may be advantageous to minimize continuous

  7. Disposable contact lenses vs. contact lens maintenance for extended wear.

    Science.gov (United States)

    Josephson, J E; Caffery, B E; Campbell, I; Slomovic, A R

    1990-01-01

    We compared a disposable extended wear contact lens modality with conventional extended wear over a 6-week period. To do so, we refit 31 patients who had successfully worn conventional extended wear contact lenses for more than 1 year. One eye was fit with the AcuvueR disposable contact lens, and a new extended wear lens of the type the patient had been wearing was placed on the other eye. At weekly intervals the disposable lens was discarded and a new disposable lens inserted. At the same time, the conventional lens on the fellow eye was cleaned, disinfected, and reinserted. After 6 weeks the ocular response, subjective impressions, and condition of the lenses in the two eyes were compared. Both lenses were then cultured. Three subjects had to discontinue disposable lens wear because of adverse reactions to trapped cellular debris and corneal microcysts. Although the results were not statistically significant, the Acuvue lens appeared to perform better than or equal to the conventional lens in biomicroscopic observation, visual acuity measurement, and subjective patient preference. Eighty-seven percent of patients preferred to continue with the disposable system. There were no differences found in the type or degree of microbial contamination of the lenses.

  8. Further studies of contact lens motion during blinking.

    Science.gov (United States)

    Conway, H D; Knoll, H A

    1986-10-01

    Contact lens motion is felt to be of increasing importance in connection with debris elimination, particularly in extended wear lenses. Thus an improved analysis is made of a simple model for investigating the initial motion of a hard contact lens over the eye during blinking. It is shown that the assumption of constant tear film thickness is a reasonable one. This greatly simplifies the analysis. Various vertical force vs. time variations are considered and lens velocity/time graphs and maximum lens displacement calculated. These are in good agreement with the results of experiment.

  9. Geometry-invariant gradient refractive index lens: analytical ray tracing.

    Science.gov (United States)

    Bahrami, Mehdi; Goncharov, Alexander V

    2012-05-01

    A new class of gradient refractive index (GRIN) lens is introduced and analyzed. The interior iso-indicial contours mimic the external shape of the lens, which leads to an invariant geometry of the GRIN structure. The lens model employs a conventional surface representation using a coincoid of revolution with a higher-order aspheric term. This model has a unique feature, namely, it allows analytical paraxial ray tracing. The height and the angle of an arbitrary incident ray can be found inside the lens in a closed-form expression, which is used to calculate the main optical characteristics of the lens, including the optical power and third-order monochromatic aberration coefficients. Moreover, due to strong coupling of the external surface shape to the GRIN structure, the proposed GRIN lens is well suited for studying accommodation mechanism in the eye. To show the power of the model, several examples are given emphasizing the usefulness of the analytical solution. The presented geometry-invariant GRIN lens can be used for modeling and reconstructing the crystalline lens of the human eye and other types of eyes featuring a GRIN lens.

  10. Particle swarm optimization applied to automatic lens design

    Science.gov (United States)

    Qin, Hua

    2011-06-01

    This paper describes a novel application of Particle Swarm Optimization (PSO) technique to lens design. A mathematical model is constructed, and merit functions in an optical system are employed as fitness functions, which combined radiuses of curvature, thicknesses among lens surfaces and refractive indices regarding an optical system. By using this function, the aberration correction is carried out. A design example using PSO is given. Results show that PSO as optical design tools is practical and powerful, and this method is no longer dependent on the lens initial structure and can arbitrarily create search ranges of structural parameters of a lens system, which is an important step towards automatic design with artificial intelligence.

  11. [Phacoemulsification of subluxated lens with capsular tension ring implantation].

    Science.gov (United States)

    Dorecka, Mariola; Rokicki, Wojciech; Nita, Malgorzata; Krysik, Katarzyna; Nita, Ewa; Sikorska, Aleksandra; Romaniuk, Wanda

    2007-01-01

    To evaluate long term results of phacoemulsification with PC IOL and capsular tension ring (CTR) implantation in lens subluxation. The study comprised of 134 patients--146 eyes with subluxated lens. In all cases phacoemulsification with PC IOL and CTR implantation was performed. No intaroperative complications has occured. Postoperative complications included: inflammation in the anterior chamber in 3 eyes (2.1%), retinal detachment in 2 eyes (1.4%). In all cases there was no PC IOL decentration. (1) CTR facilitates phacoemulsification with PC IOL implantation in lens subluxation. (2) Phacoemulsification of subluxated lens with PC IOL and CTR implantation seems to be safe and effective procedure.

  12. Acoustic Luneburg lens using orifice-type metamaterial unit cells

    Science.gov (United States)

    Park, Choon Mahn; Lee, Sang Hun

    2018-02-01

    A two-dimensional acoustic Luneburg lens that can be easily expanded into a three-dimensional sphere is fabricated. The required spatial distribution of the refractive index for this Luneburg lens is realized using the characteristics of orifice-type metamaterial unit cells. Typical characteristics of the resulting acoustic Luneburg lens, such as its aberration-free performance and capability for antipodal focusing of the lens for the incident plane waves, are investigated through experiments and simulations with the attenuation loss at frequencies that satisfy the homogeneous medium condition of the metamaterial. With the designed metamaterial, we achieved the minimum spot that lies within the classical diffraction limit at the focal point.

  13. Responses to Hypoxia and Endoplasmic Reticulum Stress Discriminate the Development of Vitreous and Floury Endosperms of Conventional Maize (Zea mays) Inbred Lines.

    Science.gov (United States)

    Gayral, Mathieu; Elmorjani, Khalil; Dalgalarrondo, Michèle; Balzergue, Sandrine M; Pateyron, Stéphanie; Morel, Marie-Hélène; Brunet, Sylvie; Linossier, Laurent; Delluc, Caroline; Bakan, Bénédicte; Marion, Didier

    2017-01-01

    Major nutritional and agronomical issues relating to maize ( Zea mays ) grains depend on the vitreousness/hardness of its endosperm. To identify the corresponding molecular and cellular mechanisms, most studies have been conducted on opaque/floury mutants, and recently on Quality Protein Maize, a reversion of an opaque2 mutation by modifier genes. These mutant lines are far from conventional maize crops. Therefore, a dent and a flint inbred line were chosen for analysis of the transcriptome, amino acid, and sugar metabolites of developing central and peripheral endosperm that is, the forthcoming floury and vitreous regions of mature seeds, respectively. The results suggested that the formation of endosperm vitreousness is clearly associated with significant differences in the responses of the endosperm to hypoxia and endoplasmic reticulum stress. This occurs through a coordinated regulation of energy metabolism and storage protein (i.e., zein) biosynthesis during the grain-filling period. Indeed, genes involved in the glycolysis and tricarboxylic acid cycle are up-regulated in the periphery, while genes involved in alanine, sorbitol, and fermentative metabolisms are up-regulated in the endosperm center. This spatial metabolic regulation allows the production of ATP needed for the significant zein synthesis that occurs at the endosperm periphery; this finding agrees with the zein-decreasing gradient previously observed from the sub-aleurone layer to the endosperm center. The massive synthesis of proteins transiting through endoplasmic reticulum elicits the unfolded protein responses, as indicated by the splicing of bZip60 transcription factor. This splicing is relatively higher at the center of the endosperm than at its periphery. The biological responses associated with this developmental stress, which control the starch/protein balance, leading ultimately to the formation of the vitreous and floury regions of mature endosperm, are discussed.

  14. Spontaneous dislocation of lens bag with acrylic lens after uneventful cataract surgery ? unusual complication of cataract surgery

    OpenAIRE

    Shah, Mehul A.; Shah, Shreya M.; Mehta, Ruchir; Shah, Prerna

    2015-01-01

    Introduction: Spontaneous dislocation of intraocular lens with bag is rare.Methods: We report a case of a 56-year-old male who presented with spontaneous anterior dislocation of an in-the-bag intraocular lens 3 years after manual small incision cataract surgery. He had undergone manual small incision cataract surgery with foldable acrylic intraocular lens implantation, and 18 months after cataract surgery ND: YAG capsulotomy with uneventful post capsulotomy follow-up. 17 months after capsul...

  15. LENS - the Low-Energy Neutrino Spectrometer

    International Nuclear Information System (INIS)

    Hahn, Richard L.

    2004-01-01

    Despite the recent successes of SNO and KamLAND, the only detectors sensitive to <1 MeV-neutrinos have been the radiochemical chlorine and gallium solar neutrino experiments. LENS is being developed to measure in real time the charge-current fluxes and energy spectra of the lowest energy solar neutrinos, from the pp and 7Be branches (91% and 7% of solar neutrinos). The detector medium will be a metal-loaded liquid scintillator (M-LS), with indium as the metal, which serves as the target for neutrino capture in the LS. 115In has 95.71% natural abundance and a 114.2-keV neutrino-capture Q-value. Neutrino capture in 115In produces a β particle and preferentially feeds an excited state of 115Sn that de-excites by delayed emission of two γ rays. This triple-coincidence 'tag' in time and space in principle is a very powerful tool to discriminate neutrino-capture events from backgrounds. The International LENS R and D Collaboration is working to develop an In-LS neutrino detector, with special properties, such as high indium content, high light yield, high optical transparency, long-term chemical stability, and good signal-to-background ratio. Success in preparing the In-LS has been achieved via the synthesis of In-carboxylates that are soluble in pseudocumene LS (note that these methods may also be applicable to the preparation of Gd-LS for reactor antineutrino experiments). Testing of some prototype LENS In-LS detector modules has begun recently at the Gran Sasso Laboratory

  16. [Corneal protection in contact lens users].

    Science.gov (United States)

    Egorova, G B; Mitichkina, T S; Shamsudinova, A R

    2014-01-01

    To evaluate the efficacy of corneoprotective agents (Corneregel and Solcoseryl) in contact lens users. A total of 66 long-term contact lens wearers with dry eye symptoms and varying degrees of corneal epitheliopathy were monitored. All patients used artificial tears, which, however, were not effective enough to suppress manifestations of corneal epitheliopathy and to release the associated discomfort. The therapy was supplemented with Corneregel. The following examination methods were applied: biomicroscopy with fluorescent staining, Norn test, Schirmer's test, advanced tearscopy with digital image analysis of the precorneal tear film lipid layer, corneal confocal microscopy. In all cases the assessment was performed prior to starting Corneregel and repeated in 7 days, 14 days and 1 month. Complete corneal re-epithelization and restoration of the most superficial layer of the epithelium were achieved within 7-14 days. In case of severe initial epitheliopathy the effect of Corneregel was not sufficient and epithelium defects remained. These patients additionally received Solcoseryl Eye Gel. After the treatment course the condition of corneal epithelium ameliorated and contact lens wearing comfort increased. A longer precorneal tear film break-up time indicated an increase of tear film stability. The total tear production did not change significantly. The moistening effect of Corneregel and low-viscosity artificial tears together with intensive regeneration of corneal epithelium enables structural recovery of the epithelial membrane and considerable improvement of the anterior corneal stroma. At the first stage of corneoprotective treatment it is appropriate to use preservative-free artificial tears of low and high viscosity. If the effect of tear substitutive therapy is unsatisfactory it is recommended to prescribe Corneregel and Solcoseryl. The regimen is to be adjusted individually.

  17. Lentil (Lens culinaris) Lipid Transfer Protein Len c 3: A Novel Legume Allergen

    NARCIS (Netherlands)

    Akkerdaas, J.; Finkina, E. I.; Balandin, S. V.; Santos Magadán, S.; Knulst, A.; Fernandez-Rivas, M.; Asero, R.; van Ree, R.; Ovchinnikova, T. V.

    2012-01-01

    Background: Lentils are increasingly consumed in many parts of the world. Two allergens, Len c 1 and 2, have been reported previously. Recently, peanut and green bean lipid transfer proteins (LTPs) have been identified as the first two members of an important group of allergens that might be

  18. Abnormal lens morphogenesis and ectopic lens formation in the absence of beta-catenin function

    Czech Academy of Sciences Publication Activity Database

    Krešlová, Jana; Machoň, Ondřej; Růžičková, Jana; Láchová, Jitka; Wawrousek, E.F.; Kemler, R.; Krauss, S.; Piatigorsky, J.; Kozmik, Zbyněk

    2007-01-01

    Roč. 45, č. 4 (2007), s. 157-168 ISSN 1526-954X R&D Projects: GA ČR GA204/04/1358 Institutional research plan: CEZ:AV0Z50520514 Keywords : Wnt * beta-catenin * gene * lens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.516, year: 2007

  19. Magnetic system of the Tevatron electron lens

    International Nuclear Information System (INIS)

    Bogdanov, I.; Kozub, S.; Pleskach, V.; Sytnik, V.; Tkachenko, L.; Zintchenko, S.; Zubko, V.; Kuznetsov, G.; Sery, A.; Shiltsev, V.

    2000-01-01

    The Tevatron Electron Lens (TEL) system consisting of seven SC and four conventional magnets has been developed and fabricated in IHEP for increase of luminosity in Tevatron. The SC cable tension and preload of SC coils are calculated. The chosen cable design and cooling of the SC magnets ensure sufficient temperature margin for operating of SC magnets and their safety during quench. The system of conventional and SC solenoids create necessary trajectory of magnetic field lines for the TEL electron beam motion. SC dipoles and warm correctors permit to carry out correction of the electron beam motion [ru

  20. Septic lens implantation syndrome in a cat.

    Science.gov (United States)

    Dalesandro, Nicole; Stiles, Jean; Miller, Margaret

    2011-09-01

    A 13-year-old female spayed domestic shorthair cat was presented initially for a change in the appearance of the left eye. On initial examination, a small penetrating wound was suspected as the cause for a corneal scar, an anterior cortical incipient cataract and mild iritis. The cat was not re-presented until 1 year later at which time ocular pain was marked. Severe anterior uveitis and glaucoma were diagnosed and the eye enucleated. Histopathology documented intralenticular coccoid bacteria and septic lens implantation syndrome. © 2011 American College of Veterinary Ophthalmologists.