Diabetic retinopathy progresses in four stages, namely:Stage 1) Mild Non-proliferative Diabetic Retinopathy (NPDR)Stage 2) Moderate Non-proliferative Diabetic RetinopathyStage 3) Severe Non-proliferative Diabetic RetinopathyStage 4) Proliferative Diabetic Retinopathy (PDR)