Retinal vascular changes in pre-diabetes and prehypertension: new findings and their research and clinical implications.

T he retinal vasculature can be viewed directly and noninvasively, offering a unique and easily accessible “window” to study the health and disease of the human microcirculation in vivo. In the last decade, advances in digital retinal photography and imaging techniques have allowed precise characterization of subtle retinal vascular changes in large populations. These retinal changes can be broadly divided into four groups: 1) classic retinal vascular changes in diabetes and hypertension (i.e., diabetic and hypertensive retinopathy), 2) isolated retinopathy signs in individuals with diabetes or hypertension (e.g., microaneurysm, retinal hemorrhage, or cotton wool spot), 3) changes in retinal vascular caliber, and 4) changes in retinal vascular architecture (e.g., retinal tortuosity). New studies in large populations now show that retinal vascular changes are common in the general population and may precede the subsequent development of overt diabetes and hypertension. A consistent pattern of associations is also emerging, showing that specific retinal vascular changes may be related differently to hyperglycemia and blood pressure. In this review, we summarize recent studies on the retinal vascular changes seen in diabetes and hypertension and speculate on potential research and clinical implications. CLASSIC RETINAL VASCULAR CHANGES