Purpose To elucidate changes in the neurosensory retina in the macular area, using spectral domain OCT and correlate with functional loss on fundus-related microperimetry, in patients with diabetes and no diabetic retinopathy compared with age-matched healthy volunteers. Methods This was a prospective study enroling 39 patients in each group. All patients underwent comprehensive dilated eye examination. The foveal thickness and the photoreceptor layer thickness at the foveal centre were measured using spectral domain OCT, and the mean retinal sensitivity of central 20 degrees was measured using microperimetry. Results The mean age of the patients with diabetes was 50.92 ± 4.75 years, and of controls, 49.87±5.50 years. SD-OCT measured photoreceptor layer thickness (PLT) to be 61.62±4.48 lm in cases, and 68.79±7.84 lm in controls (Po0.0001); foveal thickness (FT) was 168.64 ± 16.46 lm in cases and 177.74 ± 14.58 lm in controls (P ¼ 0.012). The mean retinal sensitivity (MRS) of the central 20 degrees, measured on microperimetry was 15.74±3.74 db in cases and 17.70±1.5 db in controls (Po0.003). In cases compared with controls (aged under 50 years) statistically significant differences were noted in all the three outcome variables: FT, P ¼ 0.030; PLT, P ¼ 0.015; and MRS, P ¼ 0.020. The duration of diabetes influenced only the PLT (P ¼ 0.017). Statistical analysis was performed with Student's t-test and v 2 test. Conclusion Neuronal damage was observed in those eyes that did not have clinical evidence of diabetic retinopathy.

ObjectiveThe study was aimed at estimating the prevalence of type 2 diabetes mellitus and diabetic retinopathy in a rural population of South India.DesignA population-based cross-sectional study.Participants13 079 participants were enumerated.MethodsA multistage cluster sampling method was used. All eligible participants underwent comprehensive eye examination. The fundi of all patients were photographed using 45°, four-field stereoscopic digital photography, and an additional 30° seven-field stereo digital pairs were taken for participants with diabetic retinopathy. The diagnosis of diabetic retinopathy was based on Klein's classification.Main outcome measuresPrevalence of diabetes mellitus and diabetic retinopathy and associated risk factors.ResultsThe prevalence of diabetes in the rural Indian population was 10.4% (95% CI 10.39% to 10.42%); the prevalence of diabetic retinopathy, among patients with diabetes mellitus, was 10.3% (95% CI 8.53% to 11.97%). Statistically significant variables, on multivariate analysis, associated with increased risk of diabetic retinopathy were: gender (men at greater risk; OR 1.52; 95% CI 1.01 to 2.29), use of insulin (OR 3.59; 95% CI 1.41 to 9.14), longer duration of diabetes (15 years; OR 6.01; 95% CI 2.63 to 13.75), systolic hypertension (OR 2.14; 95% CI 1.20 to 3.82), and participants with poor glycemic control (OR 3.37; 95% CI 2.13 to 5.34).ConclusionsNearly 1 of 10 individuals in rural South India, above the age of 40 years, showed evidence of type 2 diabetes mellitus. Likewise, among participants with diabetes, the prevalence of diabetic retinopathy was around 10%; the strongest predictor being the duration of diabetes.

Aim: To investigate the occurrence of neuronal damage, as the earliest change occurring, before the clinical evidence of diabetic retinopathy. Methods: 70 eyes of subjects with type 2 diabetes mellitus and with no evidence of diabetic retinopathy (cases) and 40 eyes of subjects with no diabetes mellitus (controls) were studied using spectral-domain OCT and microperimetry. The influence of age and gender on the outcome measures was also analyzed. Results: Age- and gender-matched subjects showed a decreased mean retinal nerve fiber layer thickness in cases when compared to the controls (27 vs. 33 µm; p = 0.018). Among the cases, subjects between 40 and 45 years of age showed a reduced mean central foveal thickness (175.1 vs. 198.1 µm; p = 0.05), mean retinal thickness in the central 6-mm fundus (260.5 vs. 275.3 µm; p = 0.006) and mean retinal nerve fiber layer thickness (29 vs. 39 µm; p = 0.036) when compared to the controls. However, no differences were noted in the microperimetry outcomes in cases when compared to the controls. The duration of diabetes and the glycemic control did not show any significant changes on the outcome measures in cases, except for a significantly lower mean retinal sensitivity in diabetics with glycosylated hemoglobin values <7% as compared to those with glycosylated hemoglobin ≥7% (14.1 ± 2.9 vs. 15.4 ± 1.7 dB; p = 0.027). Conclusion: The results suggest that there is some evidence of early neuronal damage particularly on spectral-domain OCT, before the clinical evidence of diabetic retinopathy, in subjects with type 2 diabetes mellitus.

BackgroundThe concordance of microalbuminuria and diabetic retinopathy (DR) has been well reported in persons with type 1 diabetes; however, for type 2 diabetes, there is paucity of data especially from population-based studies. The aim of this study was to estimate the prevalence of albuminuria (micro - and macroalbuminuria) among persons with type 2 diabetes and determine its role as a risk factor for presence and severity of DR.MethodsA population-based cross sectional study was conducted in cohort of 1414 subjects with type 2 diabetes from Chennai metropolis. All the subjects underwent comprehensive eye examination including 45 degrees four-field stereoscopic digital photography. DR was clinically graded using Early Treatment Diabetic Retinopathy Study scales. A morning urine sample was tested for albuminuria. Subjects were considered to have microalbuminuria, if the urinary albumin excretion was between 30 and 300 mg/24 hours, and macroalbuminuria at more than 300 mg/24 hours. The statistical software used was SPSS for Windows, Chicago, IL. Student t-test for comparing continuous variables, and χ2 test, to compare proportions amongst groups were used.ResultsThe prevalence of microalbuminuria in the study subjects was 15.9% (226/1414), and that of macroalbuminuria, 2.7% (38/1414). Individuals with macroalbuminuria in comparison to micro- or normoalbuminuria showed a greater prevalence of DR (60.5% vs. 31.0% vs. 14.1%, p < 0.001), and also a greater severity of the disease (60.9% vs. 21.4 vs. 9.9, p < 0.001).ConclusionsEvery 6th individual in the population of type 2 diabetes is likely to have albuminuria. Subjects with microalbuminuria were around 2 times as likely to have DR as those without microalbuminuria, and this risk became almost 6 times in the presence of macroalbuminuria.

Nearly two thirds of the diabetic population showed evidence of cataract; mixed cataracts were more common than the monotypes ones.