DEAR DOCTOR K:

I have dry eyes. What are my treatment options?

DEAR READER:

Tears are not just for crying. Your eyes are constantly making small amounts of tears to keep the surface of the eye and the underside of the eyelids moist. Tears also contain fat and mucus, substances that cleanse the eyes.

Except when you cry, tears are made in such small amounts that the liquid doesn't spill out of the eyes. You don't notice that you're making the right amount of tears, but you do notice when you're not making enough.

Tears are made by tiny glands in the eye called lacrimal glands. Dry eyes occur when your eyes don't produce enough tears. As your tear production drops off, your eyes can burn or feel itchy, scratchy or irritated. It may suddenly become difficult to wear contact lenses. You may experience a buildup of sticky mucus in your eye, or find it difficult to cry. Your eyes may become more sensitive to light.

Surprisingly, dry eyes can cause excessive tearing. These tears are "irritant tears," made in reaction to your dry eyes. They contain more water and less fat and mucus than regular tears. As a result, they just run off the eyes without lubricating them as healthy tears do.

There are many causes of dry eyes: allergic reactions, irritation from wearing contact lenses, an eyelid inflammation (a condition called blepharitis), and a disease called Sjogren's syndrome.

Dry eyes become more common when you get older, as tear production normally drops off. Women are more likely than men to get dry eyes. So are people with diabetes and people who live in places with low humidity. Certain commonly used medicines reduce the production of tears, including antihistamines, birth control pills and selective serotonin receptor antagonists (SSRIs), often used to treat depression.

Over-the-counter artificial tears mimic the makeup of natural tears, and their regular use effectively treats most cases of dry eye. Lubricating ointments can treat more serious cases, but they tend to blur vision, so apply them at bedtime. (I've put a table of over-the-counter dry eye products on my website, AskDoctorK.com.)

In severe cases, your ophthalmologist may need to insert tiny plugs made of collagen or silicone into your tear drainage ducts. The plugs help both natural and artificial tears stay on your eye longer by preventing them from draining out of the opening in the inner corner of the eyelid.

Another approach is to increase tear production. Topical cyclosporine (Restasis) decreases inflammation in the tear-producing glands, which can lead to better tear production.

If a medication you're taking is contributing to your dry eye, changing it may help.

You can also reduce dry eye symptoms by avoiding dust, pollen and cigarette smoke. Use humidifiers, which add moisture to indoor air. Also, stop wearing contact lenses while you have dry eye symptoms.

(Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.)

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