Selective effects of estradiol on human corneal endothelial cells.

In Fuchs endothelial corneal dystrophy (FECD), mitochondrial and oxidative stresses in corneal endothelial cells (HCEnCs) contribute to cell demise and disease progression. FECD is more common in women than men, but the basis for this observation is poorly understood. To understand the sex disparity in FECD prevalence, we studied the effects of the sex hormone 17-ß estradiol (E2) on growth, oxidative stress, and metabolism in primary cultures of HCEnCs grown under physiologic ([O2]2.5) and hyperoxic ([O2]A) conditions. We hypothesized that E2 would counter the damage of oxidative stress generated at [O2]A. HCEnCs were treated with or without E2 (10 nM) for 7-10 days under both conditions. Treatment with E2 did not significantly alter HCEnC density, viability, ROS levels, oxidative DNA damage, oxygen consumption rates, or extracellular acidification rates in either condition. E2 disrupted mitochondrial morphology in HCEnCs solely from female donors in the [O2]A condition. ATP levels were significantly higher at [O2]2.5 than at [O2]A in HCEnCs from female donors only, but were not affected by E2. Our findings demonstrate the resilience of HCEnCs against hyperoxic stress. The effects of hyperoxia and E2 on HCEnCs from female donors suggest cell sex-specific mechanisms of toxicity and hormonal influences.

A portable, low-cost practice model for microsurgical skills training.

PURPOSE: We describe a portable practice model for acquisition of microsurgical skills using widely available inexpensive tools and materials as a model in learning ophthalmic corneal suturing skills. METHODS: Interested participants without prior microsurgery experience affiliated with the Jacobs School of Medicine and Biomedical Sciences with no prior microsurgical experience qualified to participate. Each participant completed written informed consent. We developed a 3-dimensional micro-stellated icosahedron model using microtubules, monofilament fishing line, jewelers' forceps, and a basic laboratory dissection microscope. We tested this model in improving microsurgical skills in a randomized, controlled intervention trial. Following a pre-assessment task of passing a microsurgical needle and performing a tie, participants were randomized to a control or an intervention (building the micro-stellated icosahedrons) group. The assessment task was repeated after two weeks. Videos of pre- and post-assessments were rated by two masked ophthalmologists. Technique scores and time to complete microsurgical tasks were analyzed to determine improvement in skills. RESULTS: A total of 27 microsurgically naïve participants were recruited and randomized (14 Intervention / 13 Control). Comparing pre- and post-assessments, the intervention group showed significant decrease in time required to pass the needle (P = 0.018) and significant improvement in technical scores. (P = 0.001). In the control group, there was no significant decrease in time or improvement in technical scores. CONCLUSIONS: The portable inexpensive micro-stellated icosahedron skills acquisition model is an effective practice model to acquire skills necessary to perform a microsurgical tie. The similarity in dimensions between the model and the eye suggests translatability to ophthalmic surgery.

Comparing iStent versus CyPass with or without phacoemulsification in patients with glaucoma: a meta-analysis.

BACGROUND: The aim of this study was to conduct a meta-analysis to compare the overall intraocular pressure (IOP)-lowering effect of iStent or CyPass as isolated procedures or in combination with cataract extraction. MATERIALS AND METHODS: Cochrane review manager 5.3 software (RevMan® 5.3) was used for a meta-analysis of IOPs and the number of antiglaucoma medications in six groups according to the type and number of stents and whether the procedure was isolated or in combination with cataract extraction. MAIN RESULTS: A total of 33 out of 446 publications retrieved have been enrolled. The mean changes in IOP in the groups with one iStent and more than two iStents with concurrent cataract extraction were -3.78 ± 0.53 mmHg and -3.89 ± 0.73 mmHg, respectively. The mean differences in IOP in the groups with one iStent and more than two iStents without concurrent cataract extraction were -3.96 ± 0.25 mmHg and -7.48 ± 0.55 mmHg, respectively. The mean changes in IOP in the groups with CyPass implantation with and without concurrent cataract extraction were -4.97 ± 1.38 mmHg and -8.96 ± 0.16 mmHg, respectively. CONCLUSIONS: Both iStent and CyPass either in combination with cataract extraction or as isolated procedures effectively decrease IOP. This effect is greatest with isolated implantation of CyPass followed by multiple iStents and then single iStent implantation and lasts up to 2 years.

The effects of collagen cross-linking on corneal density: a comparison between accelerated and conventional methods.

PURPOSE: To compare the corneal density before and after accelerated versus conventional corneal cross-linking (CXL). METHODS: Pentacam densitometry and corneal mapping were performed before and 6 months following the randomly assigned intervention. Corneal density was measured over different zones and layers of the cornea by two independent ophthalmologists. Total corneal density was calculated. The patients were followed up for the occurrence of procedure-related and unrelated complication 1 week, 1 month and a final visit around 6 months (180 ± 10 days) after the procedure, during which the corneal density was remeasured and recorded. RESULTS: Twenty-three patients were enrolled. There was a significant increase in corneal density over the anterior layer (P < 0.001) and middle corneal layer (P = 0.035). Additionally, the corneal density significantly increased in 0-2 and 2-6 mm zones (P < 0.001), as well as total density (P = 0.002) following corneal CXL. Although there was no significant difference in the corneal density between the two CXL groups, the increase in corneal density was only significant in group A for the 6-10 mm zone and the posterior corneal layer. CONCLUSION: Both the conventional and accelerated CXL methods increase the overall corneal density with exception of posterior central corneal layer and the 6-10 mm zone, which is only increased in the accelerated method.

Relationship between vitreous and serum vascular endothelial growth factor levels, control of diabetes and microalbuminuria in proliferative diabetic retinopathy.

BACKGROUND: Diabetic retinopathy is a serious microvascular disorder of the retina. Vascular endothelial growth factor (VEGF) expression, induced by high glucose levels and hypoxia, is a main feature in retinopathy. The aim of this study was to evaluate the relationship between vitreous and serum VEGF levels and control of diabetes and microalbuminuria in patients with proliferative diabetic retinopathy. METHODS: Sixty-five patients were enrolled in this case-control study, comprising 30 patients with proliferative diabetic retinopathy (cases) and 35 patients with nonproliferative diabetic retinopathy (controls). The vitreous VEGF level was compared with the serum VEGF level in both groups. Glycosylated hemoglobin (HbA(1c)), microalbuminuria, serum creatinine, and stage of nephropathy and retinopathy were also measured in patients with proliferative diabetic retinopathy, and the relationship between these parameters and serum and vitreous VEGF levels was investigated. RESULTS: Mean vitreous and serum VEGF levels were significantly higher in cases compared with controls (P = 0.001, P = 0.011, respectively). There was also a significant correlation between vitreous and serum VEGF levels (P = 0.012, r = 0.453). VEGF levels in patients with well controlled blood glucose (P = 0.039), on drug treatment (P = 0.045) and at an early stage of nephropathy (P = 0.042) were significantly lower. There was a significant correlation between VEGF and albumin to creatinine ratio (P = 0.017, r = 0.432). CONCLUSION: Serum and vitreous VEGF levels was significantly lower in patients on oral therapy, in those with well controlled glycemia, and in those with early-stage retinopathy. Administration of anti-VEGF had a good effect in reducing the progression of proliferative diabetic retinopathy.