Evaluation of dynamic thiol-disulfide homeostasis in glaucoma patients and the correlation with retinal nerve fiber layer analysis.

PURPOSE: The aim of this study was to evaluate thiol/disulfide homeostasis and ischemia-modified albumin levels with primary open-angle glaucoma, ocular hypertension, and control group; also to interpret the correlation between these biochemical parameters and retinal nerve fiber layer analysis. MATERIAL AND METHODS: In a prospective cross-sectional study, 30 primary open-angle glaucoma cases, 30 ocular hypertension cases, and 30 control subjects were included in the study. Native thiol, total thiol, and disulfide measurements and disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios were evaluated as thiol-disulfide homeostasis. Albumin and ischemia-modified albumin parameters were also evaluated. All cases underwent detailed ophthalmologic examination including visual acuity, retinal nerve fiber layer via optical coherence tomography, intraocular pressure, and central corneal thickness measurements and visual field analysis by 24-2 Swedish Interactive Threshold Algorithm (SITA) Standard visual field test. RESULTS: Primary open-angle glaucoma group had significantly higher ischemia-modified albumin values than ocular hypertension and control group (p < 0.001). Native thiol and total thiol values of control group were statistically higher than those of primary open-angle glaucoma and ocular hypertension groups. The correlation between the temporal retinal nerve fiber layer value and ischemia-modified albumin, disulfide/native thiol, and disulfide/total thiol values of the primary open-angle glaucoma patients included in the study was moderate correlation in negative direction (r = -0.46, r = -0.39, r = -0.39, respectively), whereas there was a statistically significant moderate correlation in positive direction between the native thiol/total thiol values (r = 0.39) (p < 0.05). CONCLUSION: These findings have reinforced the role of oxidative stress in the etiopathogenesis of primary open-angle glaucoma, suggesting that the thinning retinal nerve fiber layer may be associated with oxidative stress in favor of prooxidant shift.

Dedifferentiation of Retinal Pigment Epithelium in a Patient With Chronic Retinal Detachment.

A 34-year-old woman presented with vision loss in her right eye, which had persisted for approximately 12 months. Funduscopy showed horseshoe retinal tear at the 8-o'clock position and retinal detachment in inferior, nasal, and temporal quadrants, with a pigmented demarcation line in the right eye. Diffuse punctate accumulations were noted on the detached retinal surface and in the vitreous. Fundus autofluorescence imaging detected diffuse punctate accumulations, which produced hyperautofluorescence spots. Cytological examination of a vitreous sample detected CD68-positive and cytokeratin- and CD45-negative macrophages. These findings indicate that epithelial-to-mesenchymal transition occurred in the retinal pigment epithelium of our patient. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:716-720.].

The Correlation between Changes in Biochemical Parameters and Central Macular Thickness in Patients with Non-Proliferative Diabetic Retinopathy.

This study aimed at evaluating the correlation between changes in Hemoglobin A1c (HbA1c) and fasting serum lipids, and Central Macular Thickness (CMT) in patients with Non-Proliferative Diabetic Retinopathy (NPDR). In the current research, both eyes of 68 patients with mild or moderate NPDR, without clinically significant macular edema, were studied. Levels of fasting serum lipids, HbAlc, and CMT were measured during the first visit and at the end of the follow-up period (3 months). For statistical analysis, CMTs of each eye were studied and the correlation of changes was investigated. Additionally, the direction of changes in CMT for each eye was determined, and whether the changes in both eyes were symmetrical was investigated. Out of 68 patients, 24 were male and 44 were female. The mean CMT of all eyes was 290.05 ± 48.90 µm during the first visit and 286.80 ± 37.57 µm on the 3rd month follow-up. The mean HbAlc was 8.71 ± 1.82% at first visit to the hospital and the mean HbAlc was 8.39 ± 1.65% at the final visit. Although the changes in HbA1c and CMT during the follow-up period were statistically insignificant, the correlation of these 2 values was statistically significant (p=0.01). However, amongst l3 patients, the CMTs were asymmetrically changed in each eye during the follow-up period. To the best of the author's knowledge, this was the first study, which indicated a significant correlation in changes of CMT and HbA1c, even amongst patients with low-grade diabetic retinopathy. Demonstration of asymmetric changes in CMT of each treatment-naive eye of the same patient, during changes in systemic conditions, was another important finding of this study.

Three Cases of Congenital Retinal Macrovessel, One Coexisting with Cilioretinal Artery.

In this report, we describe three cases of retinal macrovessel. Two of the three patients presented to our clinic for annual eye exam and had no visual complaints. The third patient presented because of vision loss in the left eye. Two patients had 20/20 best corrected visual acuity in both eyes and the third patient had 20/20 in the right eye, 20/25 in the left eye. Pupillary exams were normal. Slit-lamp examinations of the anterior segment were unremarkable. Fundus examination revealed macrovessels in the left eyes of two patients and in the right eye of one patient. The patients underwent complete ophthalmological examinations including color fundus photography for all three patients and optic coherence tomography, fundus autoflorescence, and fundus fluorescein angiography for two of the patients. Cilioretinal artery coexisting with macrovessel was seen angiography in one case. Congenital retinal macrovessel is a rare vascular condition. It is often unilateral and the vessel is an aberrantly large branch of the retinal arteries or veins. They may cross the fovea and their visual impact is minimal. The coexistence of congenital retinal macrovessel and cilioretinal artery is very rare. Visual impairment may occur in congenital retinal macrovessel due to retinal cavernous hemangioma, foveal cysts, central serous retinopathy, and other retinal vascular abnormalities.

The significance of thiol/disulfide homeostasis and ischemia-modified albumin levels to assess the oxidative stress in patients with different stages of diabetes mellitus.

This study investigated the value of Thiol/Disulfide homeostasis and ischemia-modified albumin (IMA) levels in discriminating diabetic cases with different stages of retinopathy and without retinopathy. In total, 122 patients with type 2 diabetes mellitus (DM) were enrolled in this prospective cross-sectional study. These patients were separated into three subgroups: Group 1 included 42 patients with DM and no diabetic retinopathy (DR), Group 2 included 40 patients with DM having non-proliferative DR and the Group 3 had 40 patients with DM having proliferative DR. The native thiol, total thiol, and disulfide levels and disulfide-native thiol, disulfide-total thiol, and native thiol-total thiol ratios as well as the IMA levels were analyzed and compared among the groups. There were no statistically significant differences regarding the ages and genders of the patients between the groups. The native thiol level, the total thiol level and the native thiol-total thiol ratio showed a statistically significantly reduction, while the disulfide level, the disulfide-native thiol ratio, and the disulfide-total thiol ratio showed a statistically significantly elevation in the Group 3 compared with the Group 1 and Group 2. Additionally, the mean IMA levels were statistically significantly higher in Group 3 when compared to Group 1 and Group 2 (p = .003 and p = .014, respectively). In conclusion, both Thiol/Disulfide homeostasis parameters and IMA levels increase with the progression of DR. Thiol/Disuldife homeostasis balance and IMA levels may be used a biomarker to monitor the tissue ischemia in DM and to discriminate the different stages of DR, in the future.

Novel Assay Assessment of Oxidative Stress Biomarkers in Patients with Keratoconus: Thiol-Disulfide Homeostasis.

PURPOSE: To investigate systemic oxidative stress by evaluating thiol-disulfide homeostasis using a novel automated homeostasis assay in keratoconus patients. METHODS: Twenty-eight patients with keratoconus and 30 control subjects of a similar age and gender were enrolled in the present study. The native thiol, total thiol, and disulfide levels and the disulfide-native thiol, disulfide-total thiol, and native thiol-total thiol ratios were analyzed and compared between the keratoconus and control groups using a novel automatized spectrophotometric assay. RESULTS: The median serum native thiol value was 441.5 (362.6-488.1) in the keratoconus group and 467.8 (401.8-564.6) in the control subjects. The median serum total thiol value was 467.9 (375-580.6) in the keratoconus group and 503.3 (437.7-578.5) in the control subjects. The median serum disulfide value was 20.1 (6.2-46.3) in the keratoconus patients and 16.7 (1.1-20.8) in the controls. There were significant differences between the native thiol, total thiol, and disulfide levels of the keratoconus patients and controls (p = 0.001, p = 0.04, and p = 0.03, respectively) and the disulfide-native thiol, disulfide-total thiol, and native thiol-total thiol ratios of these two groups (p = 0.02, p = 0.01, and p = 0.001, respectively). We found no significant correlation between age and any of the thiol-disulfide parameters (p > 0.05 for all values). CONCLUSIONS: There is an imbalance in the systemic thiol-disulfide homeostasis in KC patients. This metabolic imbalance may play an important role in the pathogenesis of keratoconus; thus, it can be discussed in terms of the prevention, diagnosis, and the possible treatment for keratoconus.

Objective evaluation of lens clarity after the intravitreal injection of sustained-release dexamethasone implant.

PURPOSE: To evaluate the lens densitometry values in eyes with macular edema secondary to retinal vein occlusion that were treated with intravitreal dexamethasone implants and to compare these data with those of fellow healthy control eyes. SETTING: Ulucanlar Eye Training and Research Hospital, Ankara, Turkey. DESIGN: Prospective case series. METHODS: Patients with unilateral macular edema secondary to retinal vein occlusion who were to be treated with intravitreal dexamethasone implants were recruited. The lens densitometry values measured with Scheimpflug imaging before and 3 months after the injection were compared with those in fellow healthy eyes. RESULTS: Thirty-seven patients (22 with branch retinal vein occlusion and 15 with central retinal vein occlusion) with a mean age of 61.5 years ± 11.4 (SD) (range 37 to 82 years) were included. The mean lens densitometry value at Pentacam densitometry zone 1 was significantly increased in the study eyes at 3 months compared with baseline values (baseline 9.44 ± 0.99; 3 months 9.68 ± 1.24; P = .015). At zones 2 and 3, the mean and maximum lens densitometry values in study eyes and lens thickness were similar at baseline and 3 months after injection (P > .05). The densitometry values in fellow healthy eyes were also similar at baseline and at 3 months. CONCLUSION: The mean lens densitometry value at zone 1 significantly increased from baseline in the study eyes 3 months after the injection of the dexamethasone implant for the treatment of macular edema secondary to retinal vein occlusion. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.