(RxWiki News) Patients suffering from dry eye syndrome may find relief from an unexpected source. New research suggests that caffeine may help the eye produce tears, potentially relieving the uncomfortable dryness.
Most who experience dry eye syndrome simply find it uncomfortable and bothersome, though it can cause vision loss in more severe cases.
In dry eye syndrome a malfunction occurs in the rate or quality of tear production, or they tears evaporate too quickly from the eyes.
"Try a warm compress to relieve dry eyes."
Reiko Arita, MD, PhD, from the University of Tokyo School of Medicine, initiated the study after previous research indicated frequent caffeine consumers had a reduced risk for dry eye syndrome. It was already suspected that caffeine was likely to stimulate tear glands since it was already known to increase secretions such as saliva and digestive juices.
During the randomized clinical trial, 78 participants with an average age of 34 were divided into two groups with half receiving caffeine tablets equivalent to just over four cups of coffee and the rest receiving a placebo during the first session.
They switched for the second session. All of the sessions occurred between 10 a.m. and noon, a time of day when tear production is usually stable, and tear volume was measured 45 minutes after patients took their tablets.
Participants were asked not to consume caffeine for six days before each session began. Patients had to be free of hypertension dry eye syndrome, eye allergies, glaucoma, and other eye diseases that interfere with tear production.
They found that caffeine helped with the production of tears, but that the caffeine did not affect the tear drainage rates. The net tear meniscus height increase was .08 millimeters, an increase of about 30 percent in tear volume. The tear meniscus is along the margins of the eyelid and holds up to 90 percent of tears.
In a blood analysis of two genetic variations with roles in caffeine metabolism, researchers also discovered that tear production was higher in individuals with the gene variations.
Dr. Arita said the finding must be confirmed by additional studies. He cautioned that caffeine should be used selectively since some patients are sensitive to stimulating effects.
"This is interesting and the first time I've seen an actual study that shows a beneficial effect," noted Christoper Quinn, OD, with Omni Eye Associates. "Because Dry Eye Syndrome is such a common chronic condition, any new approach to treatment is welcome."
The study was recently published in Ophthalmology, the journal of the American Academy of Ophthalmology.