Regular aspirin users may have an increased risk for macular degeneration, a leading cause of blindness.
Researchers in Australia studied more than 2,000 adults.
Their aspirin use and eye health was monitored over a 15-year period.
They found those who used aspirin regularly, defined as once or more per week during the past year, had a significantly increased risk for macular degeneration.
Doctors say this discovery warrants further study, but in the meantime, patients should not stop taking aspirin if their doctor has prescribed the drug.
Aspirin users was 0.8% at five years, 1.6% at 10 years, and 3.7% at 15 years; among regular aspirin users, the cumulative incidence was 1.9% at five years, 7% at 10 years and 9.3% at 15 years, respectively.