Levels of retinopathy
| Level | Definition |
| 10 | No retinopathy |
| 20 | ⩾1 Microaneurysm |
| 30 | Microaneurysms + minimal haemorrhages and cotton wool spots |
| 31–40 | Microaneurysms, haemorrhages, cotton wool spots, and/or venous changes in one quadrant and/or intraretinal microvascular abnormalities and/or hard exudates |
| 41–50 | Microaneurysms, haemorrhages more than level 40 + venous changes in two or more quadrants and/or intraretinal microvascular abnormalities and/or cotton wool spots |
| >50 | Severe preproliferative retinopathy with venous beading, intraretinal microvascular abnormalities and numerous cotton wool spots |
| 60 | Proliferative retinopathy |
| 70 | Proliferative retinopathy and high risk characteristics |