For many individuals, dry eye syndrome is very uncomfortable and annoying; for some though, it can escalate into a vision-threatening disease. All of the 78 participants in the new study produced significantly more tears after consuming caffeine than after taking a placebo. The study is published in the journal Opthalmology.
Dry eye syndrome occurs when there is a malfunction in the rate of tear production, the quality of tears, and/or the rate of evaporation from the surface of the eye. Anyone can experience dry eye, although it is typically more common among women. Symptoms can include gritty, scratchy or burning sensations, excessive tear, and/or stringy mucus production.
The research team was motivated by an earlier study that had shown a reduced risk for dry eye in caffeine users: 13 percent of users had the syndrome compared with nearly 17 percent of non-users. The team knew that caffeine had the capacity to stimulate tear glands, since it is known to boost other secretions, such as saliva and digestive juices.
The investigators also were aware that each person reacts differently to caffeine. To account for this, researchers analyzed study participants’ DNA samples for two genetic variations that play critical roles in caffeine metabolism. Tear production was found to be higher in study subjects who had the two genetic variations.
Lead author, Dr. Reiko Arita, claims, "If confirmed by other studies, our findings on caffeine should be useful in treating dry eye syndrome. At this point, though, we would advise using it selectively for patients who are most sensitive to caffeine's stimulating effects."
For the study, participants were divided into two groups: one received caffeine tablets in the first session and a placebo in the second session, while the other group received them in reversed order. Tear volume was measured within 45 minutes of consuming the tablets. All sessions were conducted between 10AM and noon, a time of the day when tear production is usually found to be stable. No subjects were aware of whether they received placebo or caffeine.
Dry eye syndrome can be very uncomfortable and can create vision problems. If you are experiencing ongoing symptoms, it’s important to see a seed a doctor since advanced cases can lead to eye damage and permanent vision problems. Current treatment options can range from warm compresses, eye washes and artificial tears, to medications and tear drainage devices.