Overview
Definition
Microvascular damage to the retina caused by chronic hyperglycemia.
Epidemiology
A leading cause of new-onset blindness in working-age adults (20-65 years).
Etiology & Risk Factors
- Chronic hyperglycemia leads to endothelial damage, pericyte loss, and microaneurysms.
- Retinal ischemia triggers the release of VEGF (Vascular Endothelial Growth Factor), promoting abnormal neovascularization.
Clinical Symptoms
- Often asymptomatic in early stages (emphasizes the need for annual screening)
- Floaters, blurred vision, or sudden severe vision loss (if vitreous hemorrhage or retinal detachment occurs)
- Macular edema is the most common cause of vision loss in these patients
Clinical Approach
Diagnosis
- Dilated Fundus Exam:
- Non-Proliferative (NPDR): Microaneurysms, dot-blot hemorrhages, hard exudates (lipid deposits), cotton-wool spots (nerve fiber layer infarctions)
- Proliferative (PDR): Neovascularization (new, fragile blood vessels on the optic disc or elsewhere)
Management
- Prevention: Strict glycemic and blood pressure control
- Macular Edema: Intravitreal Anti-VEGF injections or focal laser photocoagulation
- Proliferative Disease (PDR): Panretinal photocoagulation (laser therapy to destroy ischemic peripheral retina and halt VEGF production)
Complications
- Vitreous hemorrhage (fragile new vessels bleed into the vitreous cavity)
- Tractional Retinal Detachment (scar tissue from neovascularization pulls the retina off)
- Neovascular Glaucoma