Novel mechanisms of retinal vascular aging. Through collaboration with investigators at the Reynolds Oklahoma Center on Aging we have made the novel observation that normal, “physiological” aging results in focal loss of contractile smooth muscle cells on retinal arterioles. Our results provide a cellular mechanism for prior clinical studies showing vascular microirregularities and defects in vascular responsiveness in aged human subjects. We are currently examining the molecular mechanisms for these age-related vascular changes as they may contribute to age-related retinal and cerebrovascular complications