Purpose This study was undertaken to investigate the neurovascular changes in the retina of prediabetic subjects. Methods Subjects enroled in a prospective study were separated into prediabetic and normal control groups based on their glycosylated haemoglobin (HbA1C) levels, fasting and postprandial blood sugar levels and glucose tolerance test. All the subjects underwent detailed ophthalmic evaluation, which included fundus examination, fundus photography, optical coherence tomography angiography (OCTA), and multifocal electroretinogram (mfERG). Comparisons were done between the groups using the Wilcoxon signed rank test. ResultsThe median age was 48 years for the normal controls (n = 40), and 49.5 years for prediabetic subjects (n = 45) (p = 0.306). There was no difference in the vision, contrast sensitivity, thickness of the ganglion cell complex or the foveal avascular zone parameters between the groups. But the central foveal thickness and subfoveal choroidal thickness were significantly reduced in prediabetics (p < 0.01). The mfERG showed significant differences in the amplitude. The average amplitude was 35 ± 12 nv/deg 2 in the normals and 29 ± 11 nv/deg 2 in the prediabetics (p = 0.003). A weak positive correlation was noted between the mfERG and vascular parameters in the prediabetic group. Conclusions The prediabetic stage reveals earliest functional neuronal changes in the retina. The neuronal function seems to be affected much earlier than clinically appreciable structural changes in the ganglion cell complex and precedes vascular changes in the retina.

Background: Patients with central scotoma have poor fixation stability and poor visual acuity. Acoustic biofeedback training can be an effective way to train such patients to eccentrically fixate. This study analyses the mean retinal sensitivity, saccadic velocity, and fixation stability after acoustic biofeedback training and shows correlation with age and scotoma size. Methods: Patients with irreversible central scotoma in both the eyes secondary to macular diseases were selected. After undergoing comprehensive low vision assessment, 19 patients who were willing were recruited for the acoustic biofeedback training to the better eye in 10 sessions, using the MP-1 Microperimeter. Mean retinal sensitivity, saccadic velocity, fixation stability before and after the acoustic biofeedback were recorded. Results: There were 17 men and two women. Ages ranged from 19-94 years (mean 54.63 AE 24.66). The scotoma size ranged from four to 20 degrees. Ten patients had agerelated macular degeneration, four had Stargardt disease, three had traumatic macular scar, two had scarred myopic choroidal neovascular membrane, and one had myopic macular degeneration. The vision improved from 1.06 AE 0.36 to 0.86 AE 0.33 logMAR (p < 0.0001). The mean retinal sensitivity improved from 2.1 AE 2.9 dB to 2.7 AE 3.1 dB (p = 0.01), with negative correlation with age (p = 0.01) and scotoma size (p = 0.02). Fixation stability improved with reduction in the bivariate contour ellipse area (p = 0.01). It showed negative correlation with age (p = 0.02) and scotoma size (p = 0.10). The saccadic velocity reduced from 0.34 /second to 0.26 /second but was not significant (p > 0.99). The majority (58 per cent) had their preferred retinal locus superior to the fovea. There was good agreement between bivariate contour ellipse area and MP-1 Microperimeter inbuilt fixation parameters. The effect was maintained at six months with slight reduction in fixation stability. Conclusion: Acoustic biofeedback can improve fixation behaviour, visual acuity and retinal sensitivity in patients with central scotoma. The results are better with younger age and smaller scotoma size.

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The purpose of this study was to evaluate early vascular and tomographic changes in the retina of diabetic patients using artificial intelligence (AI). The study included 74 age‐matched normal eyes, 171 diabetic eyes without retinopathy (DWR) eyes and 69 mild non‐proliferative diabetic retinopathy (NPDR) eyes. All patients underwent optical coherence tomography angiography (OCTA) imaging. Tomographic features (thickness and volume) were derived from the OCTA B‐scans. These features were used in AI models. Both OCT and OCTA features showed significant differences between the groups (P < .05). However, the OCTA features indicated early retinal changes in DWR eyes better than OCT (P < .05). In the AI model using both OCT and OCTA features simultaneously, the best area under the curve of 0.91 ± 0.02 was obtained (P < .05). Thus, the combined use of AI, OCT and OCTA significantly improved the early diagnosis of diabetic changes in the retina.

Purpose: To evaluate and correlate retinal microvascular changes in prediabetic and diabetic patients with functional and systemic parameters. Methods: Optical coherence tomography angiography (OCTA) was performed on all subjects after medical evaluation and laboratory investigations for blood sugar, glycosylated hemoglobin, and others. Automated quantification of vascular indices of the superficial plexus were analyzed. Results: Hundred and eleven persons (222 eyes) were grouped into prediabetic (PDM) (60 eyes), diabetic without retinopathy (NDR) (56 eyes), diabetic with retinopathy (DR) (66 eyes), and healthy controls (CTR) (40 eyes). The superficial retinal capillary plexus showed no significant changes in the prediabetic and NDR groups; however, central foveal thickness (CFT) was significantly reduced in PDM ( P = 0.04). The circularity of the foveal avascular zone (FAZ) ( P = 0.03) and the vessel density (VD) ( P = 0.01) showed significant reduction from PDM to NDR. All vascular parameters were significantly reduced in DR and correlated with disease severity. The CFT correlated significantly with FAZ area. The VD and perfusion density were seen to correlate significantly with HbA1c and contrast sensitivity. The visual acuity was significantly correlated with the FAZ. Logistic regression revealed VD [OR 20.42 (7.9–53)] and FAZ perimeter [OR 9.8 (4.2–23.2)] as the strongest predictors of DR. Conclusion: The changes in OCTA can help predict onset of DR. FAZ changes are seen in early stages and are correlated well with systemic parameters, making it an easy target to monitor and screen for severity of DR. Significant reduction in the CFT in PDM suggests that neuronal damage precedes vascular changes.

Purpose: To evaluate the efficacy and safety of intravitreal dexamethasone implant in treatment naïve eyes with diabetic macular edema (DME). Methods: A retrospective analysis of treatment naïve eyes with DME which received intravitreal dexamethasone implant between January 2016 and March 2018 was done. Demographic details of the patients, ocular examination findings at baseline and on follow up visits were noted. Morphological features of DME and central macular thickness were noted on optical coherence tomography at each visit. The details regarding additional treatment for macular edema on follow up were noted. Results: Sixty five eyes were included in the study. The mean age was 59.14 ± 9.59 years. The follow up ranged from 6 to 48 months. Psuedophakic eyes showed visual improvement whereas the phakic eyes showed stable vision. The central foveal thickness showed significant reduction ( p = 0.05) in all the eyes. The best corrected visual acuity at final follow up (+0.65 logMAR) was slightly less as compared to baseline (+0.62 logMAR). Retreatment was needed in 37% eyes and antiglaucoma medications in 8% eyes. Cataract progression was noted in 24 eyes (37%); 17 eyes (26.1%) underwent surgery. Notably, 27 eyes (41.5%) had some degree of macular ischemia at baseline. And five eyes (7.7%) showed progression of retinopathy leading to vitreous hemorrhage. Conclusion: Dexamethasone implant is helpful in reducing the macular thickness and stabilizing the vision in treatment naïve DME; requiring less number of treatment sessions. However, it does not prevent progression of diabetic retinopathy. The visual improvement may be affected by cataract and macular ischemia.

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Background: Functional outcome of macular hole (MH) surgery can be better assessed with multifocal electroretinogram (mfERG) and microperimetry (MP). It might provide better assessment than the Snellen visual acuity alone. Objectives: To evaluate macular function with mfERG and microperimetry, and assess their correlation with visual acuity in MH. Materials and Methods: A prospective study was done in patients with unilateral,idiopathic full thickness MH. Standard surgery with vitrectomy, internal limiting membrane peeling and gas tamponade was done. Snellen and logMAR visual acuity, mfERG, microperimetry and optical coherence tomography were done pre and postoperatively. Results: Twenty six patients with unilateral macular hole and twenty five age matched controls were included. The mean age of patients was 59.92±9.39 years (range: 40 to 74 years). All the holes were closed after surgery (two required second surgery). The mean visual acuity improved from 0.77±0.34 logMAR to 0.43±0.36 (p =0.03). The mfERG amplitudes differed ring wise, but the average amplitude changed from 26.31±8.82 to 20.52±7.11 (p =0.03). The mean retinal sensitivity changed from 12.98±2.59 to 13.42±2.53 (p =0.11). There was significant correlation between visual acuity and mfERG amplitudes and retinal sensitivity. Regression equations to predict visual outcome could be derived. Conclusions: In MH, mfERG and microperimetry show reduced responses, delay in recovery of function. They show a strong correlation with visual acuity. It is possible to predict vision after surgery with the help of mfERG and MP. Improved ability to predict visual outcome can increase the utility of anatomic success predictors.