DR Medhat MRCP

Diseases of the retina
I. Diabetic retinopathy
• Epidemiology : it is the most common cause of blindness in adults aged 35-65 years-old.
• Pathogenesis :
- Hyperglycaemia retinal blood flow and abnormal metabolism in the retinal vessel
walls damage to endothelial cells & pericytes
o Endothelial damage vascular permeability which causes the
characteristic exudates seen on fundoscopy.
o Pericyte dysfunction predisposes to the formation of microaneurysms.
o Neovasculization is thought to be caused by the production of growth
factors in response to later retinal ischaemia.
• Classification & features :
I. Non-proliferative retinopathy :
Background retinopathy :
Microaneurysms (dots) + Hemorrhages (blots) ≤ 3 + Hard exudates (lipid leak)
Pre-proliferative retinopathy : ( more common in DM1, TTT: laser
photocoagulation)
Cotton Wool spots 1. Cotton Wool spots 1. Cotton Wool spots
(soft exudates, 2. Blots> 3/ dark cluster hges 2. Blots>3/dark cluster hges.
Ischaemic nerve fibres)
3. Venous beading/looping.
4