RetinaAge / fundus-based age clock

RetinaAge is a biological-age clock derived from fundus photographs of the retina, using deep-learning models trained to predict chronological age from the vascular and neural features of the optic disc, fovea, and retinal vasculature. Published by Zhu and colleagues (2022, British Journal of Ophthalmology), the model was trained on fundus images from healthy UK Biobank participants and applied to the broader UK Biobank cohort (~80,000 images, ~46,000 participants); the gap between predicted retinal age and chronological age independently predicted all-cause mortality; a separate analysis from the same group (Zhu et al., 2022, Stroke) linked the gap to arterial stiffness and incident cardiovascular disease. Because the retina shares embryological origin with the central nervous system and is the only site where microvasculature can be imaged non-invasively, it offers a clinically practical window onto systemic and neural vascular aging.