ResearchPad - eye-lens https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[3D-Reconstruction of the human conventional outflow system by ribbon scanning confocal microscopy]]> https://www.researchpad.co/article/elastic_article_15723 The risk for glaucoma is driven by the microanatomy and function of the anterior segment. We performed a computation-intense, high-resolution, full-thickness ribbon-scanning confocal microscopy (RSCM) of the outflow tract of two human eyes. We hypothesized this would reveal important species differences when compared to existing data of porcine eyes, an animal that does not spontaneously develop glaucoma.MethodsAfter perfusing two human octogenarian eyes with lectin-fluorophore conjugate and optical clearance with benzyl alcohol benzyl benzoate (BABB), anterior segments were scanned by RSCM and reconstructed in 3D for whole-specimen rendering. Morphometric analyses of the outflow tract were performed for the trabecular meshwork (TM), limbal, and perilimbal outflow structures and compared to existing porcine data.ResultsRSCM provided high-resolution data for IMARIS-based surface reconstruction of outflow tract structures in 3D. Different from porcine eyes with an abundance of highly interconnected, narrow, and short collector channels (CCs), human eyes demonstrated fewer CCs which had a 1.5x greater cross-sectional area (CSA) and 2.6x greater length. Proximal CC openings at the level of Schlemm’s canal (SC) had a 1.3x larger CSA than distal openings into the scleral vascular plexus (SVP). CCs were 10.2x smaller in volume than the receiving SVP vessels. Axenfeld loops, projections of the long ciliary nerve, were also visualized.ConclusionIn this high-resolution, volumetric RSCM analysis, human eyes had far fewer outflow tract vessels than porcine eyes. Human CCs spanned several clock-hours and were larger than in porcine eyes. These species differences may point to factors downstream of the TM that increase our vulnerability to glaucoma. ]]> <![CDATA[Factors associated with visual outcomes after cataract surgery: A cross-sectional or retrospective study in Liberia]]> https://www.researchpad.co/article/elastic_article_15712 To report the initial outcomes and associated risk factors for poor outcome of cataract surgery performed in LiberiaMethods and analysisLV Prasad Eye Institute (LVPEI), Hyderabad, started providing eye care in Liberia since July 2017. Electronic Medical Records of 573 patients operated for age-related cataract from July 2017 to January 2019 were reviewed. One eye per patient was included for analysis. All patients underwent either phacoemulsification or manual small incision cataract surgery (MSICS). Pre and postoperative uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) were recorded at one day, 1–3 weeks and 4–11 weeks. Main outcome measure was BCVA at 4–11 weeks; Intraoperative complications and preoperative ocular comorbidities (POC) were noted. BCVA less than 6/12 was classified as visual impairment (VI). Risk factor for VI was analysed using the logistic regression model.ResultsOf the 573 patients, 288 were males and 285 were females (49.7%). Mean age was 65.9±10.9 years; 14.3% had POC. The surgical technique was mainly MSICS (94.59%, n = 542). At 4–11 weeks, good outcome of 6/12 or better was noted in 38.55% (UCVA) and 82.54% (BCVA). Visual acuity (VA) of 6/18 or better as UCVA and BCVA was noted in 63.5% and 88% eyes respectively. Poor outcome of less than 6/60 was noted as UCVA (11.11%) and BCVA (5.22%). Multivariable analysis showed poor visual outcomes significantly higher in patients with POC (odds ratio 3.28; 95% CI: 1.70, 6.34).ConclusionThe cataract surgical outcomes in Liberia were good; with ocular comorbidities as the only risk factor. ]]> <![CDATA[Autosomal recessive congenital cataracts linked to HSF4 in a consanguineous Pakistani family]]> https://www.researchpad.co/article/Na302ecef-6336-4a97-9663-2461453833de

Purpose

To investigate the genetic basis of autosomal recessive congenital cataracts (arCC) in a large consanguineous Pakistani family.

Methods

All participating members of family, PKCC074 underwent an ophthalmic examination. Slit-lamp photographs were ascertained for affected individuals that have not been operated for the removal of the cataractous lens. A small aliquot of the blood sample was collected from all participating individuals and genomic DNAs were extracted. A genome-wide scan was performed with polymorphic short tandem repeat (STR) markers and the logarithm of odds (LOD) scores were calculated. All coding exons and exon-intron boundaries of HSF4 were sequenced and expression of Hsf4 in mouse ocular lens was investigated. The C-terminal FLAG-tagged wild-type and mutant HSF4b constructs were prepared to examine the nuclear localization pattern of the mutant protein.

Results

The ophthalmological examinations suggested that nuclear cataracts are present in affected individuals. Genome-wide linkage analyses localized the critical interval to a 10.95 cM (14.17 Mb) interval on chromosome 16q with a maximum two-point LOD score of 4.51 at θ = 0. Sanger sequencing identified a novel missense mutation: c.433G>C (p.Ala145Pro) that segregated with the disease phenotype in the family and was not present in ethnically matched controls. Real-time PCR analysis identified the expression of HSF4 in mouse lens as early as embryonic day 15 with a steady level of expression thereafter. The immunofluorescence tracking confirmed that both wild-type and mutant HSF4 (p.Ala145Pro) proteins localized to the nucleus.

Conclusion

Here, we report a novel missense mutation in HSF4 associated with arCC in a familial case of Pakistani descent.

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<![CDATA[Transient expression of Wnt5a elicits ocular features of pseudoexfoliation syndrome in mice]]> https://www.researchpad.co/article/5c897767d5eed0c4847d2c07

Purpose

Pseudoexfoliation (PEX) syndrome is an age-related systemic disease with ocular manifestations. The development of animal models is critical in order to elucidate the cause of the disease and to test potential treatment regimens. The purpose of this study is to report phenotypes found in mouse eyes injected with Adenovirus coding Wnt5a. Some of the phenotypes resemble those found in PEX patients while others are different.

Methods

Recombinant Adenovirus coding Wnt5a or green fluorescent protein (GFP) were injected into mouse eyes. Two months after the injection, eyes were examined for PEX phenotypes using slit lamp, fluorescence stereomicroscope, histological staining, immunostaining and transmission electron microscope.

Result

Certain ocular features of PEX syndrome were found in mouse eyes injected with recombinant Adenovirus coding Wnt5a. These features include accumulation of exfoliation-like extracellular material on surfaces of anterior segment structures and its dispersion in the anterior chamber, saw-tooth appearance and disrupted basement membrane of the posterior iris pigment epithelium, iris stromal atrophy and disorganized ciliary zonules. Ultrastructure analysis of the exfoliation material revealed that the microfibril structure found in this model was different from those of PEX patients.

Conclusion

These features, resembling signs of ocular PEX syndrome in patients, suggest that new information obtained from this study will be helpful for developing better mouse models for PEX syndrome.

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<![CDATA[Surgical management of intraocular lens dislocation: A meta-analysis]]> https://www.researchpad.co/article/5c76fe14d5eed0c484e5b438

Purpose

To compare the efficacy and safety of intraocular lens (IOL) repositioning and IOL exchange for the treatment of patients with IOL dislocation.

Methods

We systematically searched for relevant publications in English or Chinese in MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, WHO International Clinical Trial Registration Platform, Clinical Trial.gov, China Biology Medicine Database, China National Knowledge Infrastructure Database and grey literature sources. Study quality was assessed using the STROBE template for observational studies and the Cochrane template for randomized controlled trials (RCTs). Data were meta-analyzed using RevMan 5.3.

Results

The review included 14 English-language studies reporting 1 RCT and 13 retrospective case series involving 1,082 eyes. Average follow-up time was 13.7 months. Pooled analysis of 10 studies showed that the two procedures had a similarly effect on best corrected visual acuity (MD -0.00, 95%CI: -0.08 to 0.08, P = 0.99). Pooled analysis of nine studies showed no significant difference in incidence of IOL redislocation (RR 2.12, 95%CI 0.85 to 5.30, P = 0.11); pooled analysis of seven studies showed greater extent of incidence of cystoid macular edema in IOL exchange (RR 0.47, 95%CI 0.21 to 1.30, P = 0.06). Pooled analysis of three studies showed greater extent of incidence of anterior vitrectomy in IOL exchange (RR 0.11, 95%CI 0.04 to 0.33, P<0.0001). Pooled analysis of two studies showed greater postoperative spherical equivalents in IOL repositioning (MD 1.02, 95%CI 0.51 to 1.52, P<0.0001). pooled analysis suggested no significant differences between the two procedures in terms of intraocular pressure, endothelial cell density, surgically induced astigmatism, or incidence of retinal detachment, intraocular hemorrhage or pupillary block.

Conclusion

IOL repositioning and exchange are safe and effective procedures for treating IOL dislocation. Neither procedure significantly affects best corrected visual acuity and IOL redislocation. IOL exchange was superior to repositioning in terms of postoperative SE, but IOL repositioning was associated with lower incidence of anterior vitrectomy, potentially lower incidence of cystoid macular edema.

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<![CDATA[Latanoprost could exacerbate the progression of presbyopia]]> https://www.researchpad.co/article/5c5ca29cd5eed0c48441e76d

Purpose

Prostaglandin analogues (PG) reduce intra-ocular pressure by enhancing uveoscleral flow at the ciliary body, which controls accommodation via the ciliary muscle. We investigated the effect of PG on accommodation and presbyopia progression in glaucoma patients.

Methods

We conducted a clinic-based, retrospective, cross-sectional study. Inclusion criteria were bilateral phakic patients aged 40–69 years with best corrected visual acuity better than 20/30. Exclusion criteria were any disease affecting vision other than glaucoma and history of ocular surgery. Subjects with no prescription or vision-affecting disease served as controls (n = 260). The glaucoma patients were prescribed eye drops containing 0.005% latanoprost for more than six months (n = 23). We measured the binocular near add power at a distance of 30 cm in both groups and compared the results using Kaplan-Meier analysis.

Results

The mean age (± SD) of the control subjects was 51.5 ± 5.2 years and 39% were male. Similarly, the glaucoma patients had a mean age of 51.0 ± 7.2 years and 39% were male. There were no significant differences in age, gender, intra-ocular pressure, spherical equivalent, astigmatism, or anisometropia between groups. Survival analysis indicated that the glaucoma patients in this study reached the endpoint (near add power of +3.00 D) significantly earlier than control patients (P = 0.0001; generalized Wilcoxon test).

Conclusions

Exacerbation of presbyopia progression in glaucoma patients is a potential side effect of latanoprost eyedrops.

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<![CDATA[The Light Sword Lens - A novel method of presbyopia compensation: Pilot clinical study]]> https://www.researchpad.co/article/5c61e8fdd5eed0c48496f5bb

Purpose

Clinical assessment of a new optical element for presbyopia correction–the Light Sword Lens.

Methods

Healthy dominant eyes of 34 presbyopes were examined for visual performance in 3 trials: reference (with lens for distance correction); stenopeic (distance correction with a pinhole ϕ = 1.25 mm) and Light Sword Lens (distance correction with a Light Sword Lens). In each trial, visual acuity was assessed in 7 tasks for defocus from 0.2D to 3.0D while contrast sensitivity in 2 tasks for defocus 0.3D and 2.5D. The Early Treatment Diabetic Retinopathy Study protocol and Pelli-Robson method were applied. Within visual acuity and contrast sensitivity results degree of homogeneity through defocus was determined. Reference and stenopeic trials were compared to Light Sword Lens results. Friedman analysis of variance, Nemenyi post-hoc, Wilcoxon tests were used, p-value < 0.05 was considered significant.

Results

In Light Sword Lens trial visual acuity was stable in tested defocus range [20/25–20/32], Stenopeic trial exhibited a limited range of degradation [20/25–20/40]. Light Sword Lens and reference trials contrast sensitivity was high [1.9–2.0 logCS] for both defocus cases, but low in stenopeic condition [1.5–1.7 logCS]. Between-trials comparisons of visual acuity results showed significant differences only for Light Sword Lens versus reference trials and in contrast sensitivity only for Light Sword Lens versus stenopeic trials.

Conclusions

Visual acuity achieved with Light Sword Lens correction in presbyopic eye is comparable to stenopeic but exhibits none significant loss in contrast sensitivity. Such correction method seems to be very promising for novel contact lenses and intraocular lenses design.

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<![CDATA[Changes in axial length in accommodative esotropia patients with minimal hyperopic correction]]> https://www.researchpad.co/article/5c6448aed5eed0c484c2eb5b

Purpose

To compare the changes of spherical equivalent refractive error (SER) and axial length (AL) for three years in hyperopic children with minimal undercorrection according to the presence of accommodative esotropia (AE).

Methods

A total of 67 hyperopic children were enrolled. The patients were divided into 3 groups and matched by initial age upon examination; esotropic eyes with AE (AE group), fellow eyes with AE (FE group), and right eyes without esotropia (HE group). Changes of SER and AL were serially measured every six months for three years and collected data were compared among the groups.

Results

All three groups underwent significant myopic shift and AL elongation during the follow-up period. However, the least amount of change was found in the AE group. The AE group (-0.96 ± 1.38D) exhibited significantly less change in SER compared to the HE group (-1.76 ± 1.11D) and the FE group (-1.57 ± 1.33D) (both p<0.001). Meanwhile, smaller changes of AL were noticeable in the AE group (0.62 ± 0.88mm) compared to the other two groups (HE 0.99 ± 0.29mm; p<0.001, FE 0.73 ± 0.65mm; p = 0.04). The SER and AL changes were not significantly different between the HE group and FE group.

Conclusions

Esotropic eyes with AE patients with minimal undercorrection exhibited little negative shift of SER and AL elongation compared to not only hyperopic eyes without AE but also fellow eyes with AE.

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<![CDATA[A view to a kill? – Ambient bacterial load of frames and lenses of spectacles and evaluation of different cleaning methods]]> https://www.researchpad.co/article/5c23ffc6d5eed0c4840939b7

Surfaces with regular contact with the human body are typically contaminated with microorganisms and might be considered as fomites. Despite spectacles being widespread across populations, little is known about their microbial contamination. Therefore, we swab-sampled 11 worn spectacles within a university setting as well as 10 worn spectacles in a nursing home setting. The microbial load was determined by aerobic cultivation. All spectacles were found to be contaminated with bacteria, with nose pads and ear clips having the highest density, i.e. at sites with direct skin contact. Summed over all sites, the median microbial load of the university spectacles (1.4 ± 10.7 x 103 CFU cm-2) did not differ significantly from the spectacles tested in the nursing home (20.8 ± 39.9 x 103 CFU cm-2). 215 dominant bacterial morphotypes were analyzed by MALDI biotyping. 182 isolates could be assigned to 10 genera, with Staphylococcus being the most common. On genus-level, bacterial diversity was greater on nursing home spectacles (10 genera) compared to the university environment (2 genera). Four cleaning methods were investigated using lenses artificially contaminated with Escherichia coli, Micrococcus luteus, a 1:2 mixture of E. coli and M. luteus, and Staphylococcus epidermidis (the dominant isolate in our study), respectively. Best cleaning results (99% -100% median germ reduction) were obtained using impregnated wipes; dry cleaning was less effective (85% -90% median germ reduction). Finally, 10 additional worn university spectacles were cleaned with wipes impregnated with an alcohol-free cleaning solution before sampling. The average bacterial load was significantly lower (0.09 ± 0.49 x 103 CFU cm-2) compared to the uncleaned university spectacles previously investigated. Spectacles are significantly contaminated with bacteria of mostly human skin origin—including significant amounts of potentially pathogenic ones and may contribute to eye infections as well as fomites in clinical environments.

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<![CDATA[Why does the zebrafish cloche mutant develop lens cataract?]]> https://www.researchpad.co/article/5c915f9fd5eed0c48420ac5b

The zebrafish has become a valuable model for examining ocular lens development, physiology and disease. The zebrafish cloche mutant, first described for its loss of hematopoiesis, also shows reduced eye and lens size, interruption in lens cell differentiation and a cataract likely caused by abnormal protein aggregation. To facilitate the use of the cloche mutant for studies on cataract development and prevention we characterized variation in the lens phenotype, quantified changes in gene expression by qRT-PCR and RNA-Seq and compared the ability of two promoters to drive expression of introduced proteins into the cloche lens. We found that the severity of cloche embryo lens cataract varied, while the decrease in lens diameter and retention of nuclei in differentiating lens fiber cells was constant. We found very low expression of both αB-crystallin genes (cryaba and cryabb) at 4 days post fertilization (dpf) by both qRT-PCR and RNA-Seq in cloche, cloche sibling and wildtype embryos and no significant difference in αA-crystallin (cryaa) expression. RNA-Seq analysis of 4 dpf embryos identified transcripts from 25,281 genes, with 1,329 showing statistically significantly different expression between cloche and wildtype samples. Downregulation of eight lens β- and γM-crystallin genes and 22 retinal related genes may reflect a general reduction in eye development and growth. Six stress response genes were upregulated. We did not find misregulation of any known components of lens development gene regulatory networks. These results suggest that the cloche lens cataract is not caused by loss of αA-crystallin or changes to lens gene regulatory networks. Instead, we propose that the cataract results from general physiological stress related to loss of hematopoiesis. Our finding that the zebrafish αA-crystallin promoter drove strong GFP expression in the cloche lens demonstrates its use as a tool for examining the effects of introduced proteins on lens crystallin aggregation and cataract prevention.

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