My eyes are constantly red and watery. Is my diabetes to blame?
A. Paul Chous, MA, OD, FAAO, responds
You likely have a common condition known as dry eye syndrome. Symptoms include a scratchy sensation (like fine grains of sand are caught in your eyes), burning, itching, blurred and fluctuating vision, light sensitivity, redness, and watery eyes. People with diabetes have an increased risk for this disorder (known as keratoconjunctivitis sicca). One study showed that people with diabetes have a 50 percent chance of developing dry eye syndrome.
What to Know
Normal tears consist of three layers. The outer layer is made of oil and prevents evaporation from the surface of the eye. A middle layer, which is mostly water, is secreted by your tear glands. An inner mucus layer allows the middle layer to adhere to the tissue on the eye’s surface, which is naturally water repellant.
Many cases of diabetes-related dry eye are caused by autonomic neuropathy. Nerves that sense dryness control your tear glands—the same glands that produce the middle layer of your tears. Chronic high blood glucose can damage those nerves, leading to insufficient tear production. When the cornea, the window overlying the colored parts of your eye, is not well lubricated, the cells of the cornea become damaged, and nerve endings are exposed, leading to pain and reflex tearing.
Chronically high blood glucose also affects the quality of your tears by increasing the amount of glucose in those tears and disrupting their normal chemical composition, a factor that also contributes to symptoms of dry eye.
Another very common cause of dry eye is blocked oil glands in the eyelids, which results in abnormally fast evaporation of tears.
What to Do
Keeping blood glucose levels within your goal range is the first step in preventing and treating dry eye syndrome associated with diabetes.
Over-the-counter eye drops can help; just be sure to choose one that says “preservative free” on the label. If that doesn’t help, an eye doctor can treat dry eye using a variety of techniques, depending on the underlying cause. Those include artificial tear supplements designed to mimic deficient tear components, medications that reduce inflammation on the surface of the eye and thereby increase the production of tears, and tear duct plugs or laser cautery that help keep tears on the surface of the eye for a longer period of time. Treatments that improve clogged eyelid oil glands are also available.
Lifestyle changes can be effective, as well. Add omega-3 fatty acids to your diet by eating cold-water fish such as salmon or by taking a supplement that contains both omega-3s and omega-6s, such as evening primrose oil. This has been shown to increase the quantity and quality of tears. And use a humidifier to add moisture to your environment.
Dry eye syndrome affects many people over the age of 45, particularly postmenopausal women. People with diabetes are also at an increased risk. Consult with your eye doctor to be tested, diagnosed, and treated.
A. Paul Chous, MA, OD, FAAO, an optometrist in Tacoma, Washington, is an associate professor at Western University College of Health Sciences, where he teaches a course titled “Advanced Topics in Diabetes & Diabetes-Related Eye Disease.” The author of Diabetic Eye Disease: Lessons From a Diabetic Eye Doctor, he has type 1 diabetes.