Table 1.

Classification of diabetic retinopathy by Early Treatment of Diabetic Retinopathy Study (ETDRS).

Non-Proliferative Diabetic Retinopathy (NPDR)
Mild diabetic retinopathy (simple)	microaneurysms only
Moderate non-proliferative retinopathy	more than just microaneurysms, but less than severe non-proliferative retinopathy
Severe non-proliferative diabetic retinopathy	any of the following (governed by the 4/2/1 rule), and no signs of proliferative DR —>20 intra-retinal hemorrhages in each 4 quadrants of retinal circumference, —definite venous beading in at least 2 retinal quadrants, prominent intra-retinal microvascular abnormalities (IRMA) in at least 1 quadrant, —no signs of proliferative retinopathy.
Proliferative diabetic retinopathy (PDR)—one or more of the following: neovascularization and/or vitreous or preretinal hemorrhages)