Central Corneal Thickness Changes in Diabetic Retinopathy. A Prospective Observational and Correlative Study

Abstract

Generally, there is a delay of 4 to 7 years in the diagnosis of type 2 diabetes and about 20% of patients would have already developed some micro vascular complications at the time of diagnosis. To study the central corneal thickness (CCT) variation and correlate with grades of diabetic retinopathy in an adult South Indian population. The study was conducted on 184 eyes each of T2DM patients of duration more than 5 years. 98 males (53.26%) & 86 females (46.73%) were recruited. After recording age, sex and duration of diabetes, fundus examination was done. CCT measurements were determined using Ultrasonic Pachymetry. Diabetic retinopathy was classified based on ETDRS (Early diabetic retinopathy study) and mean CCT values of each group were correlated and statistically analysed using SPSS software Version 17. Out of 184 subjects recruited, 72 patients were with no diabetic retinopathy (NDR), 107 patients were with non-proliferative diabetic retinopathy (NPDR) and 5 patients were with proliferative diabetic retinopathy (PDR). The mean CCT of no diabetic retinopathy (NDR), non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) were found to be 526.14μm, 533.98μm and 555.20μm respectively. CCT was found to be thicker for diabetics with proliferative diabetic retinopathy compared to those with no retinopathy; the difference was not statistically significant (p=0.16). Uncontrolled diabetics (HbA1c >7%) had thicker corneas compared with diabetics with good control which was statistically significant (p=0.003). CCT was higher in diabetics having duration > 10 years than with duration <10 years but was not statistically significant (p=0.117).