What happens when the lights go out?

Visual function is most commonly evaluated under optimal lighting conditions using high-contrast measures such as visual acuity. However, everyday visual experience rarely occurs under such ideal circumstances. Many visual difficulties—particularly those reported by older adults and individuals with age-related macular degeneration (AMD)—emerge under low-luminance conditions or following exposure to glare, even when standard clinical measures remain relatively preserved. Dark adaptation describes the process by which the visual system recovers sensitivity after light exposure and provides a functional window into retinal health. While rod-mediated dark adaptation has been extensively studied, cone-mediated recovery plays a critical role in visually demanding everyday tasks, especially those involving rapid changes in illumination. Examining the temporal dynamics of cone-mediated dark adaptation offers an opportunity to capture functionally meaningful changes associated with normal aging and retinal disease. Understanding these processes may contribute to more comprehensive functional assessments of macular health under ecologically relevant viewing conditions.

Speaker: Beatriz Sánchez-Gavilán (PhD Candidate, Complutense University of Madrid, Department of Optometry and Vision; RCCHU Fellow, Real Colegio Complutense at Harvard University; Visiting Pre-doctoral Fellow at Schepens Eye Research Institute, Mass Eye and Ear, Harvard Medical School)