Diabetic Retinopathy

Diabetic retinopathy develops after years of hyperglycemia and worsens with hypertension, dyslipidemia, smoking, pregnancy, and puberty.

The disease progresses in two stages: nonproliferative and proliferative.

In the nonproliferative stage, the loss of pericytes weakens retinal capillaries, producing microaneurysms that appear as tiny red dots on fundoscopy.

Increased vascular permeability allows lipids to leak, forming yellow, hard exudates. Macular edema may develop at any stage of the disease and is the leading cause of blindness in diabetics.

Additionally, this stage involves worsening ischemia. Occluded capillaries and arterioles create areas of poor perfusion, producing cotton wool spots, intraretinal hemorrhages, venous beading, and intraretinal microvascular abnormalities.

In the proliferative stage, ischemia increases vascular endothelial growth factor levels, driving abnormal neovascularization.

These fragile capillaries may rupture, causing vitreous hemorrhage, or exert traction that detaches the retina, both of which can lead to vision loss.