Regular Long-Term Aspirin Use May Damage Eyes

Using aspirin for ten years or longer may raise the risk of developing late age-related macular degeneration (AMD), according to a new study.

Researchers at the University of Wisconsin (Madison, USA) conducted the Beaver Dam Eye Study, a longitudinal population-based study of age-related eye diseases conducted in Wisconsin (USA) involving 4,926 participants, aged 43-86 years at the baseline. Further examinations were performed every five years over a 20-year period (1988-1990 through 2008-2010). Participants were asked if they had regularly used aspirin at least twice a week for more than three months. The main outcome measure was incidence rates of AMD, as assessed in retinal photographs.

The results showed that there were 512 incident cases of early AMD (of 6,243 person-visits at risk) and 117 incident cases of late AMD (of 8,621 person-visits at risk) over the course of the study. Regular aspirin use 10 years prior to retinal examination was associated with late AMD, with an estimated incidence of 1.76% in regular users and 1.03% in nonusers. For subtypes of late AMD, regular aspirin use 10 years prior to retinal examination was significantly associated with neovascular AMD, but not pure geographic atrophy. Aspirin use five years prior to the retinal examination was not associated with incident early AMD. The study was published in the December 19, 2012, issue of the Journal of the American Medical Association (JAMA).

“The findings suggest that the mechanisms underlying aspirin's relationship with late AMD may be different from its immediate effects on clotting,” concluded lead author Barbara Klein, MD, MPH, and colleagues. “For instance, it could enhance choroidal neovascularization, as aspirin has been shown to increase vascular density in lab studies. Thus, it is possible that in the presence of injury, aspirin encourages the growth of aberrant new vessels.”

AMD is a medical condition, which usually affects older adults and results in a loss of vision in the center of the visual field (the macula) because of damage to the retina. It occurs in "dry" and "wet" forms, and is a major cause of blindness and visual impairment in adults 50 years of age and older. AMD can make it difficult or impossible to read or recognize faces, although enough peripheral vision remains to allow other activities of daily life. AMD begins with characteristic yellow deposits called drusen in the macula, between the retinal pigment epithelium and the underlying choroid.

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