Retinal Arterioles in Hypo-, Normo-, and Hypertensive Subjects Measured Using Adaptive Optics

PURPOSE: Small artery and arteriolar walls thicken due to elevated blood pressure. Vascular wall thickness show a correlation with hypertensive subject history and risk for stroke and cardiovascular events. METHODS: The inner and outer diameter of retinal arterioles from less than 10 to over 150 μm were measured using a multiply scattered light adaptive optics scanning laser ophthalmoscope (AOSLO). These measurements were made on three populations, one with habitual blood pressures less than 100/70 mm Hg, one with normal blood pressures without medication, and one with managed essential hypertension. RESULTS: The wall to lumen ratio was largest for the smallest arterioles for all three populations. Data from the hypotensive group had a linear relationship between outer and inner diameters (r(2) = 0.99) suggesting a similar wall structure in individuals prior to elevated blood pressures. Hypertensive subjects fell below the 95% confidence limits for the hypotensive relationship and had larger wall to lumen ratios and the normotensive group results fell between the other two groups. CONCLUSION: High-resolution retinal imaging of subjects with essential hypertension showed a significant decrease in vessel inner diameter for a given outer diameter, and increases in wall to lumen ratio and wall cross-sectional areas over the entire range of vessel diameters and suggests that correcting for vessel size may improve the ability to identify significant vascular changes. TRANSLATIONAL RELEVANCE: High-resolution imaging allows precise measurement of vasculature and by comparing results across risk populations may allow improved identification of individuals undergoing hypertensive arterial wall remodeling.