Retinal microvascular abnormalities, such as generalized and focal arteriolar narrowing, arteriovenous nicking and retinopathy, reflect cumulative vascular damage from hypertension, aging, and other processes. Epidemiological studies indicate that these abnormalities can be observed in 2-15% of the nondiabetic general population and are strongly and consistently associated with elevated blood pressure. Generalized arteriolar narrowing and arteriovenous nicking also appear to be irreversible long-term markers of hypertension, related not only to current but past blood pressure levels as well. There are data supporting an association between retinal microvascular abnormalities and stroke, but there is no convincing evidence of an independent or direct association with atherosclerosis, ischemic heart disease, or cardiovascular mortality. New computer-related imaging methods are currently being developed to detect the presence and severity of retinal arteriolar narrowing and other microvascular characteristics. When reliably quantified, retinal microvascular abnormalities may be useful as risk indicators for cerebrovascular diseases.