Table 1.

Classification of diabetic retinopathy

Diabetic retinopathy severity scaleFindings observable on dilated ophthalmoscopy
No retinopathyNo abnormalities
Mild non-proliferative diabetic retinopathyMicroaneurysms only
Moderate non-proliferative diabetic retinopathyMore than just microaneurysms but less than severe non-proliferative diabetic retinopathy
Severe non-proliferative diabetic retinopathyOne or more of the following, in the absence of proliferative diabetic retinopathy:
  • more than 20 intraretinal haemorrhages in each of four quadrants

  • definite venous beading in two or more quadrants

  • prominent intraretinal microvascular abnormalities in one or more quadrants

Proliferative diabetic retinopathyOne or more of the following:
  • extraretinal neovascularisation (NVD or NVE)

  • vitreous or preretinal haemorrhage

Mild diabetic macular oedemaSome retinal thickening or hard exudates in posterior pole but distant from the centre of the macula
Moderate diabetic macular oedemaRetinal thickening or hard exudates approaching the centre of the macula but not involving the centre
Severe diabetic macular oedemaRetinal thickening or hard exudates involving the centre of the macula
  • Adapted from the proposed international diabetic retinopathy and diabetic macular oedema disease severity scales.9 NVD = neovascularisation at the disc; NVE = neovascularisation of the retina elsewhere.