Choroidal neovascularization resulting from age-related macular degeneration (AMD) is a major cause of blindness among the elderly residing in developed nations. Current interventions for neovascular AMD can be costly and cause patient distress and are not without the potential for adverse effects. Thus, the quest to identify modifiable risk factors for AMD is important, with the potential to assist in the prevention or delay of AMD progression. In this issue of JAMA Ophthalmology, Rim and coauthors report their unexpected finding of a 1.2-fold increase in the incidence of neovascular AMD (95% CI, 1.02-1.49) among participants who exercised vigorously, using data from a large cohort (211 960 participants) of the Korean National Health Screening Program. The authors are understandably cautious in their interpretation of the results because of the observational nature of the study and the problems associated with self-reported measures of activity.