ResearchPad - cornea https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[HIF1α-mediated TRAIL Expression Regulates Lacrimal Gland Inflammation in Dry Eye Disease]]> https://www.researchpad.co/article/N65ce0a7e-ff6c-4383-b5c7-90093499f534 The purpose of this study was to investigate the expression of death ligands in the lacrimal glands (LGs), identify upstream factors that regulate their expression, and determine the functional roles of these factors in the pathogenesis of dry eye disease (DED).MethodsFor DED experiment, ex vivo coculture system with LG and in vivo murine model using a controlled environment chamber were utilized. C57BL/6 mice and hypoxia-inducible factor (HIF)-1α conditional knockout (CKO) mice were used. Immunohistochemical staining, polymerase chain reaction, and immunoblotting were performed to determine levels of death ligands including tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in DED-induced LGs. Additionally, acinar cell and CD45+ cell apoptosis was determined with neutralizing TRAIL treatment.ResultsDesiccating stress significantly increased HIF-1α expression in LG-acinar cells. Furthermore, HIF-1α deficiency significantly enhanced the infiltration of CD45+ inflammatory cells in LG and induced LG-acinar cell death. Meanwhile, only TRAIL expression was increased in DED-LG, but abrogated in HIF-1α CKO. Interestingly, the main source of TRAIL was the CD45 LG-acinar cells, but not CD45+ immune cells after DED induction. Using ex vivo coculture system, we confirmed LG-induced apoptosis of immune cells via HIF-1α-mediated TRAIL secretion following DED. Consistent with ex vivo, the insufficiency of HIF-1α and TRAIL enhanced recruitment of inflammatory cells to the LG and subsequently exacerbated ocular surface damage in DED mice.ConclusionsOur findings offer novel insight into the regulatory function of acinar cell-derived TRAIL in limiting inflammatory damage and could be implicated in the development of potential therapeutic strategies for DED. ]]> <![CDATA[Topical Pergolide Enhance Corneal Nerve Regrowth Following Induced Corneal Abrasion]]> https://www.researchpad.co/article/N6c108669-36cb-4071-9bdf-a23835756585 Neurotrophic keratopathy is a degenerative disease that may be improved by nerve growth factor (NGF). Our aim was to investigate the use of pergolide, a dopamine (D1 and D2) receptor agonist known to increase the synthesis and release of NGF for regeneration of damaged corneal nerve fibers.MethodsPergolide function was evaluated by measuring axon length and NGF levels by enzyme-linked immunosorbent assay in cultured chicken dorsal root ganglion (DRG) cells with serial doses of pergolide (10, 25, 50, 150, and 300 µg/ml) and with different concentrations of a D1 antagonist. Pergolide function was further evaluated by cornea nerve fiber density and wound healing in a cornea scratch mouse model.ResultsPergolide increased DRG axon length significantly at a dose between 50 and 300 µg/ml. Different concentrations of D1 antagonist (12, 24, 48, and 96 µg/ml) inhibited DRG axon length growth with pergolide (300 µg/ml). Pergolide (50 µg/ml) upregulated NGF expression in DRG cells at both 24 hours and 48 hours. Pergolide improved cornea nerve fiber density at both 1 week and 2 weeks. Pergolide also improved cornea wound healing.ConclusionsWe demonstrated that pergolide can act to promote an increase in NGF which promotes corneal nerve regeneration and would therefore improve corneal sensation and visual acuity in eyes with peripheral neurotrophic keratopathy. ]]> <![CDATA[Development of Transparent Acellular Dermal Matrix as Tissue-Engineered Stroma Substitute for Central Lamellar Keratoplasty]]> https://www.researchpad.co/article/Ncbc12ebe-4e7a-4aa5-9eff-b3a32e7273c0 To improve the transparency of the acellular dermal matrix (ADM) and investigate the optical, mechanical and histologic properties and biocompatibility of transparent ADM (TADM) in lamellar keratoplasty.MethodsA stepwise sectioning strategy was applied to determine the transparency distribution of the ADM, and TADM was fabricated accordingly. Transmittance measurements, uniaxial tension testing, and histologic staining were applied to detect its properties. Lamellar keratoplasty was performed in rabbits with TADM, and postoperative evaluations were conducted including the transmittance of the transplant area and histologic staining.ResultsThe transmittance of the ADM increased with increasing depth, and TADM was isolated mechanically at the deepest level. There was a significant improvement in the transmittance of the TADM compared with the ADM, and no significant difference in transmittance between dehydrated TADM and cornea was observed. The elastic modulus of TADM was significantly stronger than that of normal cornea (P = 0.004). TADM consisted of dense collagen fibrils, mainly collagen type I, and the collagen fibril diameter and interfibrillar spacing were determined to be larger than corneal stroma. After lamellar keratoplasty in rabbits, the TADM was well integrated with the host cornea, and transparent cornea without neovascularization was observed at 6 months. Re-epithelization was completed at 1 month, and keratocyte repopulation and collagen remodeling were observed in the graft 3 and 6 months after surgery.ConclusionsThis study presents the transparency distribution of the ADM and a method for obtaining TADM, which demonstrates ideal transparency, strong mechanical properties, and satisfactory biocompatibility when applied in lamellar keratoplasty. ]]> <![CDATA[Ocular surface and tear film changes in workers exposed to organic solvents used in the dry-cleaning industry]]> https://www.researchpad.co/article/N6840e79e-1c57-49df-9829-1ba3fd26bb8e

Workers in the dry-cleaning industry are exposed to organic solvents that may cause eye irritation and tear film changes. Objective To quantify changes in the ocular surface and tear film in dry cleaners exposed to organic solvents and associate these changes with ocular irritation as reported in a symptom questionnaire for dry eye diagnosis. Methods This was a case and control study in which the characteristics and eye-irritation symptoms were compared between two groups of 62 participants that were either exposed or not exposed to organic solvents. A general optometric examination and the following test were performed: lipid interferometry, Lissamine Green Stain, tear breakup time, Schirmer I, conjunctival impression cytology and the Donate dry eye symptoms questionnaire. Results Sixty-five percent of exposed workers obtained a higher score than 13 on the Donate dry eye symptoms questionnaire which indicated the presence of more irritation symptoms than those in the non- exposed group. A Chi-square analysis indicated the exposed group reported significantly higher incidences (P <0.005) for eye irritation symptoms of sandy sensation; tearing eyes sensation; foreign body sensation; tearing; dry eye; dryness; eyestrain and heavy eyelids. A Mann Whitney-U indicated greater severity only for symptoms relating to dry eye; sandy sensation; foreign body sensation, tearing; tearing eyes and dryness. There was a statistically significant difference (P <0.05) for Schirmer I; tear break up time; and the ocular surface assessed with Lissamine green staining and conjunctival impression cytology between groups. A reduction in the thickness of the lipid layer in the exposed group compared to the non-exposed group was observed. Surprisingly, clinical test outcomes were not significantly correlated with dry eye symptoms nor years of exposure. Conclusion Workers in the dry-cleaning industry exposed to organic solvents are associated with changes in ocular surface and tear film generating irritation symptoms commonly present in evaporative dry eye.

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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[Generation of TGFBI knockout ABCG2+/ABCB5+ double-positive limbal epithelial stem cells by CRISPR/Cas9-mediated genome editing]]> https://www.researchpad.co/article/5c6c7575d5eed0c4843cfdce

Corneal dystrophy is an autosomal dominant disorder caused by mutations of the transforming growth factor β-induced (TGFBI) gene on chromosome 5q31.8. This disease is therefore ideally suited for gene therapy using genome-editing technology. Here, we isolated human limbal epithelial stem cells (ABCG2+/ABCB5+ double-positive LESCs) and established a TGFBI knockout using RNA-guided clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing. An LESC clone generated with a single-guide RNA (sgRNA) targeting exon 4 of the TGFBI gene was sequenced in order to identify potential genomic insertions and deletions near the Cas9/sgRNA-target sites. A detailed analysis of the differences between wild type LESCs and the single LESC clone modified by the TGFBI-targeting sgRNA revealed two distinct mutations, an 8 bp deletion and a 14 bp deletion flanked by a single point mutation. These mutations each lead to a frameshift missense mutation and generate premature stop codons downstream in exon 4. To validate the TGFBI knockout LESC clone, we used single cell culture to isolate four individual sub-clones, each of which was found to possess both mutations present in the parent clone, indicating that the population is homogenous. Furthermore, we confirmed that TGFBI protein expression is abolished in the TGFBI knockout LESC clone using western blot analysis. Collectively, our results suggest that genome editing of TGFBI in LESCs by CRISPR/Cas9 may be useful strategy to treat corneal dystrophy.

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<![CDATA[Interleukin-13 maintains the stemness of conjunctival epithelial cell cultures prepared from human limbal explants]]> https://www.researchpad.co/article/5c6b2698d5eed0c484289d28

To use human limbal explants as an alternative source for generating conjunctival epithelium and to determine the effect of interleukin-13 (IL-13) on goblet cell number, mucin expression, and stemness. Human limbal explants prepared from 17 corneoscleral rims were cultured with or without IL-13 (IL-13+ and IL-13-, respectively) and followed up to passage 2 (primary culture [P0]–P2). Cells were characterized by alcian blue/periodic acid–Schiff (AB/PAS) staining (goblet cells); immunofluorescent staining for p63α (progenitor cells), Ki-67 (proliferation), MUC5AC (mucin, goblet cells), and keratin 7 (K7, conjunctival epithelial and goblet cells); and by quantitative real-time polymerase chain reaction for expression of the p63α (TP63), MUC5AC, MUC4 (conjunctival mucins), K3, K12 (corneal epithelial cells), and K7 genes. Clonogenic ability was determined by colony-forming efficiency (CFE) assay. Using limbal explants, we generated epithelium with conjunctival phenotype and high viability in P0, P1, and P2 cultures under IL-13+ and IL-13- conditions, i.e., epithelium with strong K7 positivity, high K7 and MUC4 expression and the presence of goblet cells (AB/PAS and MUC5AC positivity; MUC5AC expression). p63α positivity was similar in IL-13+ and IL-13- cultures and was decreased in P2 cultures; however, there was increased TP63 expression in the presence of IL-13 (especially in the P1 cultures). Similarly, IL-13 increased proliferative activity in P1 cultures and significantly promoted P0 and P1 culture CFE. IL-13 did not increase goblet cell number in the P0–P2 cultures, nor did it influence MUC5AC and MUC4 expression. By harvesting unattached cells on day 1 of P1 we obtained goblet cell rich subpopulation showing AB/PAS, MUC5AC, and K7 positivity, but with no growth potential. In conclusion, limbal explants were successfully used to develop conjunctival epithelium with the presence of putative stem and goblet cells and with the ability to preserve the stemness of P0 and P1 cultures under IL-13 influence.

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<![CDATA[Axial length and its associations in a Russian population: The Ural Eye and Medical Study]]> https://www.researchpad.co/article/5c5df355d5eed0c484581168

Purpose

To assess the normal distribution of axial length and its associations in a population of Russia.

Methods

The population-based Ural Eye and Medical Study included 5,899 (80.5%) individuals out of 7328 eligible individuals aged 40+ years. The participants underwent an ocular and systemic examination. Axial length was measured sonographically (Ultra-compact A/B/P ultrasound system, Quantel Medical, Cournon d'Auvergne, France).

Results

Biometric data were available for 5707 (96.7%) individuals with a mean age of 58.8±10.6 years (range:40–94 years; 25%, 50%, 75% quartile: 51.0, 58.0, 66.0 years, respectively). Mean axial length was 23.30±1.10 mm (range: 19.02–32.87mm; 95% confidence interval (CI): 21.36–25.89; 25%, 50%, 75% quartile: 22.65mm, 23.23mm, 23.88mm, resp.). Prevalences of moderate myopia (axial length:24.5-<26.5mm) and high myopia (axial length >26.5mm) were 555/5707 (8.7%;95%CI:9.0,10.5) and 78/5707 (1.4%;95%CI:1.1,1.7), respectively. Longer axial length (mean:23.30±1.10mm) was associated (correlation coefficient r2:0.70) with older age (P<0.001;standardized regression coefficient beta:0.14), taller body height (P<0.001;beta:0.07), higher level of education (P<0.001;beta:0.04), higher intraocular pressure (P<0.001;beta:0.03), more myopic spherical refractive error (P<0.001;beta:-0.55), lower corneal refractive power (P<0.001;beta:-0.44), deeper anterior chamber depth (P<0.001;beta:0.20), wider anterior chamber angle (P<0.001;beta:0.05), thinner peripapillary retinal nerve fiber layer thickness (P<0.001;beta:-0.04), higher degree of macular fundus tessellation (P<0.001;beta:0.08), lower prevalence of epiretinal membranes (P = 0.01;beta-0.02) and pseudoexfoliation (P = 0.007;beta:-0.02) and higher prevalence of myopic maculopathy (P<0.001;beta:0.08). In that model, prevalence of age-related macular degeneration (any type: P = 0.84; early type: P = 0.46), diabetic retinopathy (P = 0.16), and region of habitation (P = 0.27) were not significantly associated with axial length.

Conclusions

Mean axial length in this typically multi-ethnic Russian study population was comparable with values from populations in Singapore and Beijing. In contrast to previous studies, axial length was not significantly related with the prevalences of age-related macular degeneration and diabetic retinopathy or region of habitation.

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<![CDATA[Myopia is associated with education: Results from NHANES 1999-2008]]> https://www.researchpad.co/article/5c59fecad5eed0c484135472

Purpose

Myopia is increasing worldwide and possibly linked to education. In this study, we analyse the association of myopia and education in the U.S. and investigate its age-dependency.

Methods

We conducted a secondary data analysis using the public use files from the cross-sectional study National Health and Nutrition Examination Survey of the period from 1999 to 2008. 19,756 participants aged 20 to 85 years were included with data on education and ophthalmic parameters (distance visual acuity, objective refraction and keratometry). Spherical equivalent, astigmatism, corneal power and corneal astigmatism were evaluated for an association with education using linear regression analysis with adjustment of potential confounders.

Results

Analysis revealed an association between spherical equivalent and educational level in the univariate analysis (P < .001), and in the adjusted model (P < .001). Subjects who attend school to less than 9th grade had a mean spherical equivalent of 0.34 D, subjects with 9-11th grade -0.14 D, subjects that finished high school -0.33 D, subjects with partial college education -0.70 D, subjects that graduated from college or a higher formal education -1.22 D. Subjects that graduated from college or above were -1.47 D more myopic compared to subjects that completed less than 9th grade school in the adjusted analyses. Astigmatism and corneal curvature was not associated with education.

Conclusions

Myopia is associated with higher education in the U.S. Our analysis shows that corneal curvature does not contribute to this association, therefore axial elongation or lens power are likely to contribute to myopia.

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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[Trinucleotide repeat expansion length as a predictor of the clinical progression of Fuchs’ Endothelial Corneal Dystrophy]]> https://www.researchpad.co/article/5c57e6cbd5eed0c484ef3e0d

Purpose

To determine if CTG18.1 TNR expansion length prognosticates the clinical progression of Fuchs’ Endothelial Corneal Dystrophy (FECD).

Methods

This was a prospective cohort study. A total of 51 patients with newly diagnosed FECD were recruited and followed-up over a period of 12 years, from November 2004 to April 2016. Baseline clinical measurements included central corneal thickness (CCT), endothelial cell density (ECD) and CTG18.1 TNR expansion length from peripheral leukocytes, with yearly repeat measurements of CCT and ECD. A patient was defined to have experienced significant clinical progression and to have developed Threshold Disease if any of these criteria were fulfilled in either eye: a) CCT increased to >700μm, b) ECD decreased to <700 cells/mm2, or c) underwent keratoplasty for treatment of FECD.

Results

Patients were categorized as having at least one allele whose maximum allele length was equal to or greater than 40 repeats (L≥40, n = 22, 43.1%), or having both alleles shorter than 40 repeats (L<40). Threshold Disease rates at the 5-year time point were 87.5% for the L≥40 group and 47.8% for the L<40 group (p = 0.012). This difference narrowed and was no longer statistically significant at the 8-years (92.9% vs 78.9%, p = 0.278) and 10-years (92.9% vs 84.2%, p = 0.426) time points.

Conclusions

L≥40 patients are at greater risk of FECD progression and development of Threshold Disease within the first 5 years following diagnosis.

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<![CDATA[Mouse model of ocular hypertension with retinal ganglion cell degeneration]]> https://www.researchpad.co/article/5c466550d5eed0c4845188e3

Objectives

Ocular hypertension is a primary risk factor for glaucoma and results in retinal ganglion cell (RGC) degeneration. Current animal models of glaucoma lack severe RGC cell death as seen in glaucoma, making assessment of physiological mediators of cell death difficult. We developed a modified mouse model of ocular hypertension whereby long-lasting elevation of intraocular pressure (IOP) is achieved, resulting in significant reproducible damage to RGCs.

Results

In this model, microbeads are mixed with hyaluronic acid and injected into the anterior chamber of C57BL/6J mice. The hyaluronic acid allows for a gradual release of microbeads, resulting in sustained blockage of Schlemm’s canal. IOP elevation was bimodal during the course of the model’s progression. The first peak occurred 1 hours after beads injection, with an IOP value of 44.69 ± 6.00 mmHg, and the second peak occurred 6–12 days post-induction, with an IOP value of 34.91 ± 5.21 mmHg. RGC damage was most severe in the peripheral retina, with a loss of 64.1% compared to that of untreated eyes, while the midperiphery exhibited a 32.4% loss, 4 weeks following disease induction.

Conclusions

These results suggest that sustained IOP elevation causes more RGC damage in the periphery than in the midperiphery of the retina. This model yields significant and reproducible RGC degeneration.

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<![CDATA[Microbial contamination and tissue procurement location: A conventional operating room is not mandatory. An observational study]]> https://www.researchpad.co/article/5c3e4f47d5eed0c484d73ac0

Background

Standard operating rooms (SOR) are assumed to be the best place to prevent microbial contamination when performing tissue procurement. However, mobilizing an operating room is time and cost consuming if no organ retrieval is performed. In such case, non-operating dedicated rooms (NODR) are usually recommended by European guidelines for tissue harvesting. Performing the tissue retrieval in the Intensive care unit (ICU) when possible might be considered as it allows a faster and simpler procedure.

Objective

Our primary objective was to study the relationship between the risk of microbial contamination and the location (ICU, SOR or NODR) of the tissue retrieval in heart-beating and non-heart-beating deceased donors.

Materials and method

We retrospectively reviewed all deceased donors’ files of the local tissue banks of Montpellier and Marseille from January 2007 to December 2014. The primary endpoint was the microbial contamination of the grafts. We built a multivariate regression model and used a GEE (generalized estimating equations) allowing us to take into account the clustered structure of our data.

Results

2535 cases were analyzed involving 1027 donors. The retrieval took place for 1189 in a SOR, for 996 in a hospital mortuary (NODR) and for 350 in an ICU. 285 (11%) microbial contaminations were revealed. The multivariate analysis found that the location in a hospital mortuary was associated with a lower risk of contamination (OR 0.43, 95% CI [0.2–0.91], p = 0.03). A procurement performed in the ICU was not associated with a significant increased risk (OR 0.62, 95% CI [0.26–1.48], p = 0.4).

Conclusion

According to our results, performing tissue procurement in dedicated non-sterile rooms could decrease the rate of allograft tissue contamination. This study also suggests that in daily clinical practice, transferring patients from ICU to SOR for tissue procurement could be avoided as it does not lead to less microbial contamination.

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<![CDATA[Who’s opting-in? A demographic analysis of the U.K. NHS Organ Donor Register]]> https://www.researchpad.co/article/5c3667d3d5eed0c4841a65ba

The NHS Organ Donor Register (NHS ODR) is a centralised database for U.K. residents wishing to be organ donors. Opt-in membership to the NHS ODR demonstrates an expression of a wish to donate, which can be key in decisions made by family members at time of death. By examining the demographic breakdown of the 24.9 million registrants, campaigns can be better targeted to increase membership among those groups underrepresented on the NHS ODR. Data from the NHS ODR (as of March 2017) was analysed using Chi2 Goodness of Fit analyses and Chi2 Test of Independence for the categorical variables of gender, nation of residency at time of registration, ethnicity, organ preference, registration age and age at registration. Goodness of fit analyses showed significant differences between demographic representation on the NHS ODR compared to the U.K. population. Cramer’s V showed significant associations were only of note (above 0.1) for age, ethnicity in the U.K. as a whole and ethnicity in England. Older (70+) and younger people (0–14) were underrepresented and those of White Ethnicity overrepresented on the NHS ODR. Although association strength was weak, more women and less residents of England were present compared to the U.K. population. Tests of independence showed significant differences between age at registration and current age on the register and cornea donation preferences. These results indicate areas for targeting by campaigns to increase NHS ODR membership. By understanding the strength of these associations, resources can be utilised in areas where underrepresentation is larger and will have the most impact to demographics of the NHS ODR. Additionally, by identifying which groups are over and underrepresented, future research can explore the reasons for this in these demographic groups.

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<![CDATA[Predictive factors for efficacy and safety in refractive surgery for myopia]]> https://www.researchpad.co/article/5c1d5bced5eed0c4846eca43

Purpose

To evaluate the predictive factors for safety and efficacy in laser refractive surgery for myopia

Setting

A singular refractive surgery center, at a University-affiliated tertiary medical center.

Design

Retrospective cohort study

Methods

Study population—A total 8,775 eyes having laser refractive laser procedures for myopia (in4,623 patients).

Observation procedures–Using a prospective database of refractive procedures performed over the span of 13 years, variables such as gender, age, type of surgery, date of surgery, pre-operative corneal thickness and Spherical Equivalent (SEQ) were evaluated.

Main outcome measures—Proportion of patients with Safety index higher than 0.85 and Efficacy index higher than 0.80.

Results

91.9% and 86.0% of all evaluated eyes were above the safety and efficacy cut-off levels, respectively. Younger age was significantly correlated with safety and efficacy indices above the cut-off levels (p<0.001). Male gender was significantly correlated with efficacy above the cut-off level (p<0.001). Myopic eyes with lower SEQ were associated with both safety (p = 0.002) and efficacy (p<0.001) indices above the cut-offs. The surgical procedure was found to significantly affect the outcome only using univariate analysis: Safety was higher in Photorefractive Keratectomy (PRK), while Efficacy was higher in Laser Assisted In Situ Keratomileusis (LASIK) (p<0.001, respectively) but no difference was found using multivariate analysis. Safety index above the cut-off level increased over the years (p<0.001).

Conclusions

Efficacy in refractive surgery for myopia is correlated with younger age, male gender and low myopia. Safety is correlated with younger age, low myopia and increases over the years. Multivariate analysis found no differences between PRK and LASIK regarding safety and efficacy.

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<![CDATA[Is Sjögren’s syndrome dry eye similar to dry eye caused by other etiologies? Discriminating different diseases by dry eye tests]]> https://www.researchpad.co/article/5c0ed78bd5eed0c484f1436c

Purpose

Dry Eye Disease (DED) is part of several conditions, including Sjögren’s syndrome (SS) and no single test to diagnosis DED. The present study intends to evaluate whether a set of signs and symptoms of DED can distinguish: a) SS from other non-overlapping systemic diseases related to DED; b) primary and secondary SS.

Methods

182 consecutive patients with DED were evaluated under five groups: SS, graft-versus-host disease (GVHD), Graves' orbitopathy (GO), diabetes mellitus (DM), glaucoma under treatment with benzalkonium chloride medications (BAK). Twenty-four healthy subjects were included as control group (CG). The evaluation consisted of Ocular Surface Disease Index (OSDI), Schirmer test (ST), corneal fluorescein staining (CFS) and tear film break up time (TFBUT). Indeed, a subset of DED patients (n = 130), classified as SS1, SS2 and nonSS (NSS) by the American-European Criteria were compared. Quadratic discriminant analysis (QDA) classified the individuals based on variables collected. The area under Receiver Operating Characteristics (ROC) curve evaluated the classification performance in both comparisons.

Results

Comparing SS with other diseases, QDA showed that the most important variable for classification was OSDI, followed by TFBUT and CFS. Combined, these variables were able to correctly classify 62.6% of subjects in their actual group. At the discretion of the area under the ROC curve, the group with better classification was the control (97.2%), followed by DM (95.5%) and SS (92.5%). DED tests were different among the NSS, SS1 and SS2 groups. The analysis revealed that the combined tests correctly classified 54.6% of the patients in their groups. The area under the ROC curve better classified NSS (79.5%), followed by SS2 (74.4%) and SS1 (69.4%).

Conclusions

Diseases that causes DED, and also SS1, SS2 and NSS are distinguishable conditions, however a single ocular tools was not able to detect the differences among the respective groups.

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<![CDATA[Patterning the insect eye: From stochastic to deterministic mechanisms]]> https://www.researchpad.co/article/5bf71f6dd5eed0c484dcb59a

While most processes in biology are highly deterministic, stochastic mechanisms are sometimes used to increase cellular diversity. In human and Drosophila eyes, photoreceptors sensitive to different wavelengths of light are distributed in stochastic patterns, and one such patterning system has been analyzed in detail in the Drosophila retina. Interestingly, some species in the dipteran family Dolichopodidae (the “long legged” flies, or “Doli”) instead exhibit highly orderly deterministic eye patterns. In these species, alternating columns of ommatidia (unit eyes) produce corneal lenses of different colors. Occasional perturbations in some individuals disrupt the regular columns in a way that suggests that patterning occurs via a posterior-to-anterior signaling relay during development, and that specification follows a local, cellular-automaton-like rule. We hypothesize that the regulatory mechanisms that pattern the eye are largely conserved among flies and that the difference between unordered Drosophila and ordered dolichopodid eyes can be explained in terms of relative strengths of signaling interactions rather than a rewiring of the regulatory network itself. We present a simple stochastic model that is capable of explaining both the stochastic Drosophila eye and the striped pattern of Dolichopodidae eyes and thereby characterize the least number of underlying developmental rules necessary to produce both stochastic and deterministic patterns. We show that only small changes to model parameters are needed to also reproduce intermediate, semi-random patterns observed in another Doli species, and quantification of ommatidial distributions in these eyes suggests that their patterning follows similar rules.

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<![CDATA[Epithelial defects after penetrating keratoplasty in infectious keratitis: An analysis of characteristics and risk factors]]> https://www.researchpad.co/article/5c0841efd5eed0c484fcb332

To investigate the clinical characteristics, treatment, risk factors of occurrence and graft transparency of corneal epithelial defects after penetrating keratoplasty in patients with infectious keratitis. 594 patients (594 eyes) with infectious keratitis treated by penetrating keratoplasty at Shandong Eye Institute were reviewed retrospectively between January 2008 and January 2018. We investigated the demographic data, diameter and sources of graft, onset time, location, scope, time of healing and treatment of epithelial defects, as well as other postoperative complications and graft clarity. 114 of the 594 grafts (19.2%) that developed epithelial defects were included in the epithelial defects group, while the other 480 patients were classified in the non-defect group. The mean age of patients with epithelial defects was statistically greater than that of patients without epithelial defects (P = 0.006). The epithelial defects group accounted for a larger proportion of male patients (P<0.001). The proportion of patients with a graft diameter >9mm in the epithelial defect group (29.8%) was more than that in the non-defects group (16.3%) (P = 0.001). The incidence of epithelial defects significantly differed among the pathogenic causes of infectious keratitis (P = 0.002). The incidence of graft infection (21.1%, 9.2%, respectively, P<0.001) and graft dysfunction (7.9%, 2.5%, respectively, P = 0.012) in the epithelial defect group was higher than in the non-defects group. Multivariate logistic regression revealed that male sex (P = 0.001), age ≥ 60 years (P = 0.024), graft diameter >9mm (P = 0.001), bacterial (P = 0.039) and herpes simplex keratitis (P = 0.008), rheumatism (P = 0.031) and cancer treated with chemo- or radiotherapy (P = 0.032) were independent risk factors for epithelial defects. Graft clarity after epithelial defects were significantly differed between fungal and viral infections (P<0.001). We found that being an elderly male patient, a graft diameter >9 mm, bacterial and viral keratitis and systemic diseases (including rheumatism and cancer treated with chemo- or radiotherapy) were independent risk factors for postoperative epithelial defects.

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<![CDATA[Corneal endothelium features in Fuchs’ Endothelial Corneal Dystrophy: A preliminary 3D anterior segment optical coherence tomography study]]> https://www.researchpad.co/article/5c09944cd5eed0c4842ae9a3

Purpose

To evaluate the feasibility of 3D anterior segment optical coherence tomography (AS-OCT) for the detection of corneal endothelial features in patients with Fuchs’ Endothelial Corneal Dystrophy (FECD).

Methods

Twenty patients with clinical diagnosis of FECD (group A), and 20 control subjects (group B) were enrolled. In all patients a complete ophthalmological examination was performed, including best corrected visual acuity (BCVA), slit lamp examination for subjective grading of FECD and corneal endothelial specular microscopy. A 512x128 AS-OCT cube centered on the corneal apex was performed, and then the inner surface of the cornea was visualized and analyzed individually.

Results

Overall, the study participants were adults (mean age was 57.35 ± 8.45 years [mean ± SD] 80% female) with a BCVA ranged from 1.3 to 0 LogMAR. The OCT analysis disclosed three different patterns of the corneal endothelium (1, 2, 3) according to the signal distribution and the level of reflectivity: a homogenous, hypo-reflective surface (pattern 1); the presence of hyper-reflective orange-yellowish points (pattern 2); and a mottled appearance with a variable number of hyper-reflective areas (pattern 3). The distributions of these morphological models in the two populations were as follows: patterns 1, 2 and 3 were observed respectively in 0%, 80%, and 20% of patients in group A, and in 80%, 20% and 0% of subjects in group B. Correlation analysis unveiled a positive relationship between OCT corneal endothelium reflectivity and the clinical severity score (assessed with biomicroscopy), as well as an inverse relationship between the OCT pattern and the integrity of corneal endothelium.

Conclusion

3D AS-OCT is a useful tool in investigation of endothelial features and therefore may represent a valuable support in the setting of FECD diagnosis and staging.

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<![CDATA[Polyvinyl alcohol-iodine induced corneal epithelial injury in vivo and its protection by topical rebamipide treatment]]> https://www.researchpad.co/article/5c2400dcd5eed0c484099742

Periocular povidone-iodine (PI) and polyvinyl alcohol-iodine (PAI) have had a major role in the prevention of endophthalmitis. The purpose of this study was to investigate the corneal epithelial toxicity of PAI in a rabbit eye model using corneal resistance (CR) measurement, which is a good indicator of cell barrier function. Rabbit eyes were administered PAI solution at 4-, 6-, 8-, or 16-fold dilution with physiological saline solution (saline) or saline alone (control), to the conjunctival sac with/without wash-out with saline. Corneal epithelial injury assessed by fluorescein staining and the CR ratio was measured at 10 minutes (min) to 96 hours (h) after the initial administration. Histological observation was performed in the eyes following the PAI or control administrations. At 120 min after administration of PAI solution, the CR ratio was decreased and superficial punctate keratopathy (SPK) was significantly increased in each of the PAI-administered groups compared to the control. Recovery of CR and SPK after administration of 6- or 8-fold dilution of PAI was significantly delayed in eyes that were not subsequently washed with saline compared with eyes that were. Pre- or post-instillation of 2% rebamipide ophthalmic suspension significantly reduced PAI induced-SPK and -decrease of CR ratio. The CR method was able to accurately and quantitatively evaluate fine corneal epithelial injury. It is suggested that eyes should be washed with saline solution after administration of PAI solution or the instillation of rebamipide to prevent or reduce corneal epithelial injury.

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