The Prevalence of Diabetic Retinopathy in Tehran Province

To determine the prevalence and characteristics of retinopathy in diabetic residents of Tehran province, Iran during 2005.

This cross-sectional study was performed on 700 diabetic subjects who were recognized in a sample of 7500 individuals in the "Risk Factor Evaluation for Non-Contagious Diseases" project in I.R. of Iran, 2005. All subjects were recalled to attend a predefined location for the study. All participants underwent systemic examination by an internist and a comprehensive eye examination including dilated funduscopy by a vitreoretinal specialist.

Overall 634 diabetic subjects with mean age of 59.3±12.0 (range 18-78 years) were studied. Retinopathy was detected in 37.9% (95% confidence interval [CI], 34.1%-41.6%) including 72.9% (95%CI, 67.3%-78.5%) non-proliferative and 27.1% (95%CI, 21.5%-32.7%) proliferative diabetic retinopathy. The prevalence of bilateral blindness was 2.1% and 0.8% in diabetic patients with and without retinopathy, respectively (P<0.001). Logistic regression revealed that diabetic retinopathy is associated with male gender (P=0.022), increased disease duration (P<0.001), diabetes control regimen (P<0.001) and presence of diabetic nephropathy (P=0.003).

Regarding the high prevalence of diabetic retinopathy and the associated visual impair-ment, regular screening of diabetic patients for early detection of proliferative retinopathy and timely laser photocoagulation is highly recommended.