Caffeine Relieves Dry Eye

Dry eyes — when your eyes don't make enough tears, or tears evaporate quickly from the surface of eyes — are a problem for at least 4 million Americans. They are common after the age of 50, especially among women. For most people, the burning, gritty feeling of dry eye syndrome (DES) is simply uncomfortable and annoying, but for others it escalates into a vision-threatening disease. Researchers at the University of Tokyo's School of Medicine have shown for the first time that simply increasing caffeine intake can significantly increase the eye's ability to produce tears. All of the 78 participants in the new study produced significantly more tears after consuming caffeine than after taking a placebo. The study appears in Ophthalmology, the journal of the American Academy of Ophthalmology. An earlier study had hinted that caffeine users had a reduced risk for dry eye: 13 percent of users had the syndrome compared with nearly 17 percent of non-users. In addition, the researchers knew that caffeine stimulated secretions such as tear glands, saliva, and digestive juices. They also knew that people respond differently to caffeine, so they analyzed study participants' DNA samples looking for two genetic variations that are important in the metabolism of caffeine. They found that tear production was higher in subjects who had the two genetic variations. The study subjects were divided into two groups: One received caffeine tablets in the first session and a placebo in the second session, while the order was reversed for the other group. Researchers measured tear volume within 45 minutes of consuming the tablets. The subjects didn't know whether they had received caffeine or the placebo. All abstained from caffeine use for six days prior to each session and used no drugs during the sessions. To be eligible for the study, subjects had to be free of high blood pressure, dry eye syndrome, allergies that affect the eye, glaucoma, and other eye diseases and conditions that can interfere with tear production. "If confirmed by other studies, our findings on caffeine should be useful in treating dry eye syndrome," said Dr. Reiko Arita, M.D., Ph.D. "At this point, though, we would advise using it selectively for patients who are most sensitive to caffeine's stimulating effects." See an ophthalmologist if symptoms of dry eye persist, since advanced cases can cause eye damage and permanent vision problems. Current treatment options range from simple warm compresses, eye washes, and artificial tears to medications and tear drainage devices.