Retinal Vascular Dysfunction Relates to Cognitive Impairment in Alzheimer Disease

Cerebral vascular dysregulation has been increasingly implicated as a risk factor in the development of Alzheimer disease (AD) 1; however, because of the difficulties associated with assessing and visualizing the cerebral vasculature directly, the ability to detect such dysregulation, noninvasively, is currently limited. 2 Consequently, one concept that is being increasingly explored is the possibility of using the eye as a "window to the brain"; this approach has reasonable scientific validity as the retinal and brain vessels share a large number of embryological, anatomic, and functional similarities. 2 Indeed, previous research has demonstrated a correlation between cognition and the geometry of the retinal vessels in elderly people. 3 The aim of this pilot study, therefore, was to explore whether microvascular functional anomalies are evident at the retinal level in mild AD patients and to determine whether these anomalies relate to the degree of concurrent cognitive deficit.