Diabetic retinopathy: fluorescein angiogram showing the blood vessels of the retina of a person suffering from diabetes. Diabetic retinopathy is the most common cause of preventable blindness in Western society. Its cause is obscure, although adult non-insulin dependent patients are more susceptible. Early (background) changes, as seen here, affect the small arterioles & capillaries, with the formation of microaneurysms (white spots in central macula area), haemorrhages & areas of capillary closure. Progression leads to loss of vision from exudates, oedema & ischaemia.