Caffeine can increase tear production and may someday be a treatment for dry eye syndrome, a new study shows. All of the participants in this small study produced more tears after taking caffeine than after taking a placebo. The researchers knew that caffeine can affect people differently, so they tested participants for two genetic variants that are related to response. They found that those who had the two variants also produced the most tears. It’s estimated that caffeine affects about half of all people, though this varies by ethnic group. An earlier study showed that only about 13% of caffeine users had dry eye, compared to 17% of non-users.
About 5% of the U.S. population has dry eye syndrome. It’s more common in women and after age 50. Dry eye sufferers are not able to maintain the healthy layer of tears needed to keep the eye moist and make good vision possible. Their eyes can sting and burn. In some people, dry eye escalates into a vision-damaging disease.
It’s important to see an ophthalmologist if symptoms continue. Treatment options range from simple warm compresses, eye washes and artificial tears to medications and tear drainage devices. Much more research on the caffeine-tear production connection is needed before doctors will know how to best use it to treat dry eye.