Gritty, scratchy eyes that burn—that’s the norm for the four million Americans who suffer from dry eye syndrome.
But new research shows that a certain substance—high amounts of which are found in a very popular beverage—helps add moisture to dry eyes from the inside out.
Here’s what to sip on to find relief…
ONE STIMULATING SUBSTANCE
Earlier studies had shown that just 13% of caffeine users had dry eyes while 17% of people who didn’t drink beverages containing caffeine suffered from the problem. So Japanese researchers set out to examine caffeine’s impact on tear volume.
Dry eye syndrome can vary greatly in severity, so to keep measurements standard, researchers decided to study healthy adults who did not have dry eye syndrome. To prepare for the study, subjects did not have any caffeine for six days before each of the two test sessions. At the first test session, subjects randomly took either a placebo pill or a caffeine pill with the amount of caffeine depending on body weight. Six days later, at the second test session, subjects took the opposite. In each session, subjects didn’t know which kind of pill they were taking. Researchers measured tear volume one hour and two hours after subjects consumed the caffeine and the placebo.
Findings: Tear volume was 30% higher, on average, after both one and two hours, when subjects had ingested the caffeine versus the placebo. Future studies hopefully will explore how long this tear volume increase will last.
HOW MUCH CAFFEINE TO CONSUME
If you suffer from dry eye syndrome, consider consuming caffeine each day while continuing to use whatever dry eye treatment you normally use (such as eyedrops), and see if it helps, said lead study author Reiko Arita, MD, PhD. However, pregnant and nursing women, people with GERD, peptic ulcers or heart conditions and those using certain drugs and supplements, such as certain antidepressants, antipsychotics, anticoagulants and muscle relaxants, should check with their doctors before consuming caffeine, because it could lead to unwanted side effects or adverse interactions.
How much caffeine? If you want to approximate the amount taken by the people in the study, Dr. Arita said, follow these guidelines. If you weigh…
- 90 pounds or less, 200 mg of caffeine per day
- 91 to 128 pounds, 300 mg of caffeine per day
- 129 to 165 pounds, 400 mg of caffeine per day
- 166 to 205 pounds, 500 mg of caffeine per day
- 206 pounds or more, 600 mg of caffeine per day
You can take caffeine in pill form (a bottle of 100 tablets, 200-mg each costs as little as $6 on Web sites such as Amazon.com). Caffeine is also, as you know, easy to get through many beverages—just remember that amounts vary depending on the brand and/or how the drink is made. Coffee, of course, is king with 95 mg to 200 mg per eight-ounce cup. But you can also drink black tea (14 mg to 61 mg per eight-ounce cup) or green tea (24 mg to 40 mg per eight-ounce cup), for example. Plenty of other foods and beverages contain caffeine, such as soda, iced tea, energy drinks and chocolate, but they can be loaded with sugar and calories.
Study subjects took their designated caffeine amounts all at once—rather than spacing it out—but see what makes your peepers feel best. Since it’s unclear exactly how long the effect might last, you may want to time your consumption around day-to-day activities that heavily involve your eyes—for instance, have it an hour or two before completing a major computer task or watching a movie.
If the caffeine causes insomnia, try consuming it before mid-afternoon. If that doesn’t help, or if it gives you the jitters or makes you overly anxious, then the benefits might not outweigh the side effects. Keep in mind that everybody responds to caffeine differently, said Dr. Arita—one person might feel shaky after half a cup of coffee, while another might need five cups to feel alert throughout the day.
Whether you choose to consume caffeine or not, remember that dry eye syndrome can lead to serious health problems, such as impaired vision or infection. So ask your ophthalmologist how often you should make appointments to keep tabs on the condition of your eyes.