Eye-opening findings link caffeine, tear production

Tokyo-Caffeine intake can significantly increase the eye’s ability to produce tears, researchers at the University of Tokyo’s School of Medicine have found. The finding could help in treating dry eye syndrome.

In results from this double-masked, placebo-controlled, crossover study reported in Ophthalmology, all of the 78 participants produced significantly more tears after consuming caffeine than after taking a placebo.

The study subjects were divided into two groups: one received caffeine tablets in the first session and a placebo in the second session, and the order was reversed for the other group. Tear volume was measured within 45 minutes of subjects’ consumption of the tablets.

The research team, led by Reiko Arita, MD, PhD, was motivated by an earlier study that had shown a reduced risk for dry eye in caffeine users. The team suspected that caffeine stimulates tear glands, because it is known to increase other secretions such as saliva and digestive juices.

“If confirmed by other studies, our findings on caffeine should be useful in treating dry eye syndrome,” Dr. Arita said. “At this point, though, we would advise using it selectively for patients who are most sensitive to caffeine’s stimulating effects.”

The study is available here: http://www.ophsource.org/periodicals/ophtha/article/S0161-6420(11)01139-0/abstract.

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