Diabetic Retinopathy

Diabetic retinopathy is retinal damage caused by diabetes-related microvascular injury. Prolonged hyperglycemia changes the small retinal vessels, impairs blood flow, and allows vessels to leak fluid or blood. When capillaries close, retinal tissue becomes ischemic. The eye may respond by producing fragile new vessels that bleed easily. Longer diabetes duration, elevated A1C, increased blood pressure, dyslipidemia, anemia, proteinuria, pregnancy in a person with type 1 diabetes, and existing severe retinopathy are associated with development or progression. Early damage produces non-proliferative diabetic retinopathy (NPDR). Findings may include microaneurysms, intraretinal hemorrhages, vascular changes, and leakage. NPDR ranges from mild to severe. It often causes no symptoms, so normal-looking vision does not exclude clinically important disease. Progression is not judged from symptoms alone. Leakage at the macula can cause diabetic macular edema (DME). The macula supports sharp central vision; swelling there may cause blurred reading vision, difficulty recognizing faces, or distorted lines. Centre-involved DME affects the central macula and can threaten detailed vision. Ischemia can drive proliferative diabetic retinopathy (PDR), in which abnormal new vessels grow on the retina or optic disc. These...