People regularly taking aspirin could be at a greater risk of developing a leading cause of blindness, findings of a study published in the Journal of the American Medical Association's Internal Medicine suggest.

Researchers from the University of Sydney looking at data from 2,389 people found that those taking the painkiller long-term had a 2.5 fold risk of developing wet age-related macular degeneration, which ultimately leads to vision loss.

Eye tests performed on study participants after 15 years showed that aspirin takers had a 9.3% risk of the condition versus 3.7% for those not taking the drug, independent of a history of cardiovascular disease and smoking.

According to the researchers, given that the disease was only picked up at 10 and 15 year follow-up, cumulative dosing is likely play an important role in development of the condition.

The benefits of aspirin are well documented; millions of people regularly take the drug for its blood-thinning properties, while there is growing evidence that its regular consumption can also help ward off certain cancers.

Given its widespread use, "any increased risk of disabling conditions will be significant and affect many people," the study authors note.

Caution in 'at-risk' patients

They do stress that their findings are insufficient to warrant a blanket change in clinical practice, but suggest it may be appropriate for healthcare professionals to discuss the potentially small risk of wet AMD with long-term aspirin therapy in patients already at greater risk from the condition. 

Helen Jackman, chief executive of UK charity the Macular Society, has urged patients prescribed aspirin not to stop taking the drug without speaking to their doctors.

"For patients with cardiovascular disease who are taking aspirin, the risk of heart attack is higher than the risk of developing wet AMD," she said, but also stressed that “patients with wet AMD in one eye should have their other eye carefully monitored so that any sign of wet AMD can be found quickly".