The age-dependent decrease in the myogenic response of retinal arterioles as studied with the Retinal Vessel Analyzer

PURPOSE: To study the age-dependent change in myogenic response of retinal arterioles.METHODS: Fifty-one healthy volunteers with at least ten persons in each of the five age decades (I-V) between 20 and 69 years were subjected to diameter measurement of retinal arterioles using the Retinal Vessel Analyzer (RVA) during rest and during an increase in the systemic blood pressure when lifting hand weights. The transmural pressure in the retinal arterioles during the procedures was estimated from the blood pressure and the intraocular pressure and was compared to the accompanying diameter response.RESULTS: The retinal arteriolar diameter showed a significant decrease as a function of increasing weight for the two younger age groups below the age of 40 years (P=0.007, group I, and P=0.049, group II), compatible with perfect autoregulation, whereas no such change was observed in persons above this age (P=0.41, 0.053, 0.29 for groups III-V, respectively).CONCLUSION: Studies on autoregulation in retinal disease should consider the normal age-related decrease in diameter response of retinal arterioles when the blood pressure is changed.