Researchers Discover Simple Dry Eye Syndrome Treatment
Dry eye syndrome is a common and often chronic health problem—particularly in older adults—where patients suffer from insufficient tears to lubricate and nourish the eye. Insufficient tearing can result from either a decreased amount of tear production or when tears evaporate too quickly from the eye. Tears are necessary for maintaining the health of the outer surface of the eye by washing away foreign matter and by reducing the risk of infection. Tears also aid vision by keeping the eye surface smooth and clear.
Keratoconjunctivitis sicca (KCS) is the medical term for dry eye syndrome and results in patients experiencing irritated, gritty, scratchy, or burning eyes, a feeling of something in their eyes, excess watering, and blurred vision. While most cases of dry eye syndrome are primarily an annoyance, advanced dry eyes can damage the front surface of the eye and impair vision.
An adequate amount of tearing is necessary to prevent dry eye syndrome from developing. Tears consist of layers of water, oil and mucus. The middle water layer hydrates the cells on the surface of the eye and acts as a wash. The outer oil layer helps prevent the water layer from evaporating too quickly and the inner mucus layer functions to help spread tears evenly over the eye surface.
While the most common treatment for managing dry eye syndrome is with over-the-counter artificial tear solutions, researchers have recently discovered that caffeine from a source such as a daily morning cup of coffee may be all a person needs to treat or prevent dry eye syndrome.
In a recent study in print in the journal Ophthalmology, researchers from the University of Tokyo's School of Medicine conducted an experiment with two aims. The primary aim was to examine the effect of caffeine on tear volume, while a secondary aim was to determine whether people with variations of specific genes experienced increased or decreased tear volume following exposure to caffeine.
This aims of the study were based on an earlier study that demonstrated that caffeine users had a lower risk of dry eye syndrome, as well as the fact that caffeine stimulates bodily secretions such as saliva and digestive juices and that individuals possess variations of caffeine-metabolizing DNA sequences.
The double-masked, placebo-controlled, crossover study design consisted of two groups in which one group received a caffeine tablet in one test session and a placebo during a second test session. The second group received the same caffeine and placebo tablets, but in reverse order. Both groups had abstained from caffeine for 6 days prior to the study, did not have dry eye syndrome, glaucoma or other eye diseases/conditions that could skew the results of the study. Forty-five minutes after taking the caffeine tablet or placebo, the test subjects’ tear volumes were measured.
What the researchers found was that there was a statistically significant increase in tear volume following consumption of the caffeine tablet in comparison to taking the placebo control. Furthermore, that genetic variations in caffeine-metabolizing sequences appear to have some effect on tear production.
The researchers concluded that caffeine intake does increase tear volume and that variations within the ADORA2A and CYP1A2 caffeine-metabolizing sequences are associated with tear increase after caffeine intake. However, they believe that the genetic variation is of limited clinical significance.
"If confirmed by other studies, our findings on caffeine should be useful in treating dry eye syndrome," says Dr. Reiko Arita, lead author of the study. "At this point, though, we would advise using it selectively for patients who are most sensitive to caffeine's stimulating effects."
If you believe that you are experiencing dry eye syndrome, health experts advise that you alert your physician to this possibility as patients with symptoms of dry eyes may also have rheumatoid arthritis, diabetes and thyroid problems.
Reference: “Caffeine Increases Tear Volume Depending on Polymorphisms within the Adenosine A2a Receptor Gene and Cytochrome P450 1A2” Article in Press: published online Ophthalmology 15 February 2012 doi:10.1016/j.ophtha.2011.11.033; Reiko Arita, MD, PhD, et al.