Hypertensive Retinopathy

Diabetic retinopathy

Diabetic retinopathy is the most common cause of blindness in adults aged 35-65 years-old.

Pathophysiology

Hyperglycaemia is thought to cause increased retinal blood flow and abnormal metabolism in the retinal vessel walls. This precipitates damage to endothelial cells and pericytes

Endothelial dysfunction leads to increased vascular permeability which causes the characteristic exudates seen on fundoscopy. Pericyte dysfunction predisposes to the formation of microaneurysms. Neovasculization is thought to be caused by the production of growth factors in response to retinal ischaemia

Classification

Patients are typically classified into those with non-proliferative diabetic retinopathy (NPDR), proliferative retinopathy (PDR) and maculopathy.

Non-proliferative diabetic retinopathy

Mild NPDR

• 1 or more microaneurysm

Moderate NPDR

• microaneurysms
• blot haemorrhages
• hard exudates
• cotton wool spots ('soft exudates' - represent areas of retinal infarction), venous beading/looping and intraretinal microvascular abnormalities (IRMA) less severe than in severe NPDR

Severe NPDR

• blot haemorrhages and microaneurysms in 4 quadrants
• venous beading in at least 2 quadrants
• IRMA in at least 1 quadrant