Four risk factors for severe visual loss in diabetic retinopathy. The third report from the Diabetic Retinopathy Study. The Diabetic Retinopathy Study Research Group.

The Diabetic Retinopathy Study (DRS) Research Group has so far identified four retinopathy factors that increase the two-year risk of developing severe visual loss. The risk grows as the number of risk factors increases. Eyes with three or more risk factors (eyes with "high-risk characteristics") are at a much higher risk than eyes with two or fewer factors. The DRS protocol was changed in 1976 to require consideration of treatment for these "high-risk" eyes.