Table 1.

Classification of diabetic retinopathy

Diabetic retinopathy severity scale	Findings observable on dilated ophthalmoscopy
No retinopathy	No abnormalities
Mild non-proliferative diabetic retinopathy	Microaneurysms only
Moderate non-proliferative diabetic retinopathy	More than just microaneurysms but less than severe non-proliferative diabetic retinopathy
Severe non-proliferative diabetic retinopathy	One 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 retinopathy	One or more of the following: extraretinal neovascularisation (NVD or NVE) vitreous or preretinal haemorrhage
Mild diabetic macular oedema	Some retinal thickening or hard exudates in posterior pole but distant from the centre of the macula
Moderate diabetic macular oedema	Retinal thickening or hard exudates approaching the centre of the macula but not involving the centre
Severe diabetic macular oedema	Retinal 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.