NSC International term American term Features
R0 No DR Grade 0 Normal retina
R1 Mild NPDR Grade 1 Retinal hemorrhages & microaneurysms
R2 Moderate NPDR Grade 2 Extensive microaneurysm, retinal hemorrhage, and hard exudates
R2 Severe NPDR Grade 3 Venous abnormalities, large blot hemorrhages, cotton wool spots, IRMA.
R3 PDR Grade 4a NVD or NVE
R3 Pre-retinal fibrosis ± tractional RD Grade 4b Fibrovascular proliferation, RD, preretinal or vitreous hemorrhage, glaucoma
M0 No maculopathy   No maculopathy
M1 Diabetic maculopathy   Severe form:
  • CSME
  • Exudative form
  • Ischemic form
Milder forms:
  • Exudate ≤ 1DD of centre of fovea
  • Circinate or group of exudates within macula
  • Any microaneurysm or hemorrhage ≤ 1DD of centre of fovea only if associated with BCVA of ≤ 6/12
P Photocoagulation Grade 4b Small retinal scars throughout the peripheral retina
Table 1: Grading of diabetic retinopathy.