Diabetic retinopathy is broadly divided into non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). The severity reflects how much the retinal blood vessels have been damaged.
Non-proliferative Stages
In NPDR, existing vessels leak or become blocked but new vessels have not yet grown. Changes range from mild (small microaneurysms) through moderate to severe, where many vessels are closed and the risk of progression is high.
- Mild NPDR: a few microaneurysms and tiny haemorrhages
- Moderate NPDR: more widespread leakage and bleeding
- Severe NPDR: extensive vessel closure and warning signs for PDR
- Diabetic macular oedema can occur at any NPDR stage if the macula swells
Proliferative and Advanced Disease
PDR is characterised by fragile new blood vessels growing on the retina or optic nerve, which can bleed into the vitreous and form scar tissue. Advanced stages may lead to tractional retinal detachment or neovascular glaucoma.
- Proliferative changes carry a high risk of sudden severe sight loss
- Treatments include panretinal photocoagulation and intravitreal injections
- Vitrectomy surgery may be needed if there is dense bleeding or detachment
- Regular monitoring allows treatment to be timed before permanent damage occurs
