The presence of diabetic retinopathy is strongly related to the duration of diabetes. After 20 years of diabetes, virtually all type 1 and 60-70% of type 2 diabetics have evidence of retinopathy. In type 2 diabetes, duration may be difficulty to determine accurately, and approximately 20% may have retinopathy at the time of first recognition of diabetes. In the first 5 years of type 1 diabetes, vision-threatening retinopathy is rarely seen. Factors that affect progression or retinopathy are glycemic control, hypertension, and pregnancy. There is an association between plasma lipid levels and hard exudates, which usually a found in the macular region. Regular dilated eye examinations are necessary to diagnose retinal or macular changes that may be amenable laser photocoagulation. The efficacy and safety of this procedure h been scientifically demonstrated in two major National Institutes Health sponsored trials: the Diabetic Retinopathy Study and the Early Treatment Diabetic Retinopathy Study (ETDRS).