Taking aspirin for 10 years could more than double the risk of sight loss, according to a new study.
Scientists say taking aspirin could increase the chance of developing wet age-related macular degeneration (AMD) - an eye disorder that can lead to blindness.
A team from the University of Wisconsin used data from the Beaver Dam Eye Study on age-related eye diseases.
Eye exams were performed every five years over a 20-year period on nearly 5,000 participants. The volunteers, aged 43 to 86, were then asked if they had regularly used aspirin at least twice a week for more than three months. The average duration of follow-up was 14.8 years.
For the study, the researchers measured the incidences of different types of AMD. Wet AMD makes up just 10 per cent of cases but causes severe vision loss, while dry AMD is more common and milder - although it can develop into wet AMD at any time.
Results showed there were 512 cases of dry AMD and 117 cases of wet AMD over the course of the study for journal JAMA.
The researchers found those who took aspirin for 10 years had a 1.4 per cent risk of developing wet AMD compared to just 0.6 per cent of non-users. There was no association found between taking aspirin and developing dry AMD.
Dr Barbara Klein said: ‘Aspirin use in the United States is widespread, with an estimated 19.3 percent of adults reporting regular consumption, and reported use increases with age.
‘The results of cross-sectional studies of aspirin use and its relation to age-related macular degeneration (AMD) have been inconsistent.
‘AMD is a potentially blinding condition for which prevalence and incidence are increasing with the increased survival of the population, and regular use of aspirin is common and becoming more widespread in persons in the age range at highest risk for this disease.
‘Therefore, it is imperative to further examine this potential association.
‘Our findings are consistent with a small but statistically significant association between regular aspirin use and incidence of neovascular AMD (wet AMD).’
The most common cause of blindness in the elderly, age-related macular degeneration affects a quarter of over-60s in the UK and more than half of over-75s.
The team said further research would be needed to confirm the findings. If true it could help develop ways to prevent wet AMD.
Aspirin is often referred to as a wonder drug. Besides acting as a painkiller aspirin acts as an anti-inflammatory agent.
The pill thins the blood and a low daily dose of 75mg has been found to reduce the risk of clots forming in the blood.
Research suggests the benefits of taking a daily aspirin outweigh the small risk of side-effects in patients with heart disease, although a doctor should always be consulted.
A series of studies involving 200,000 patients found the pill also cut the risk of dying of cancer by 37 per cent if taken for five years.
However, haemophiliacs and those with ulcers should not take it. Nor should children under 16 as it has been linked to an often fatal condition called Reye’s syndrome.
By Claire Bates