Middle-aged patients regularly using aspirin for a decade or more increased their chance of developing the neovascular form of the disease, which can cause blindness.
Although the overall risk was low, with only one extra case of AMD for every 130 patients on aspirin, researchers warned it was 'imperative' to examine any possible link because of the drug's widespread use.
Almost a fifth of adults in the US regularly take aspirin for pain relief, rheumatological diseases, or to prevent cardiovascular disease.
Results from previous research into an association between aspirin and AMD had proved inconclusive, the researchers said. To investigate, the team, from the University of Wisconsin School of Medicine and Public Health, looked at data from 4,962 participants in a study of age-related eye diseases. These patients, aged 43-86 years, had been screened every five years over a 20-year period and asked about their aspirin use.
Researchers used these data to calculate an estimated dose per day, and compared this with incidence of AMD. Their analysis adjusted for other health factors including BP, medication use and alcohol intake.
The researchers found that regular aspirin use for 10 years before retinal examination was associated with a 63% greater RR of late AMD. Incidence was 1.76% among aspirin users, compared with 1.03% in non-users.
In particular, the risk of neovascular AMD was 120% higher in aspirin users, but the study found no link between aspirin use and pure geographic atrophy or incident early AMD.
The researchers concluded: 'Our findings are consistent with a small but statistically significant association between regular aspirin use and incidence of neovascular AMD.
'If confirmed, defining the causal mechanisms may be important in developing methods to block this effect to prevent or retard the development of neovascular AMD in persons who use aspirin, especially to prevent cardiovascular disease.'
JAMA 2012; 308: 2469-78