Q. I'm 38 and have had a mild case of diabetes for three years. I know that in the long run diabetes can damage my eyes; right now my vision is 20/20, and I don't have any eye problems. How often should I have my eyes checked?

A.In general, people with diabetes should have their eyes checked once a year, or more often if they're having any eye problems.

Diabetes is the leading cause of new cases of blindness in people under 75. It also raises the odds of developing glaucoma and cataracts -- other threats to vision. And because early treatment can help preserve eyesight -- by reducing severe damage as much as 60 percent -- regular eye checks are important.

Recently, the World Health Organization set up some guidelines for diabetic eye care: People over 30 should have a complete eye exam when diabetes is first discovered.

Following that exam, you should get yearly eye checks, unless your eye doctor advises exams more or less often, depending on your condition.

Women with diabetes who are pregnant or planning a pregnancy within a year should be under the care of an ophthalmologist. In some cases, pregnancy can severely worsen diabetic eye disease.

People with diabetes should see an ophthalmologist promptly for any unusual visual symptoms or loss of vision.

People whose retinas show signs of damage by diabetes should see a retinal specialist or an ophthalmologist experienced in treating this condition. The retina is the delicate layer of nerves of vision lining the back of the eye. In most cases, laser therapy helps prevent further retinal damage and preserves vision.

People whose vision has already been severely affected should take advantage of rehabilitation programs for individuals with impaired vision.

For further information about diabetes and your eyes, including low-vision programs in the Washington area, contact a local chapter of the American Diabetes Association.

Another resource for people with vision problems is a self-help organization called The Dim View. Contact Talking Books through the Special Services Dept., Fairfax County Public Library, currently located in the John Marshall Library, 6209 Rose Hill Dr., Alexandria, Va. 22310. (703) 971-0030. TDD or voice 971-6612.

Jay Siwek, a family physician from Georgetown University, practices at the Fort Lincoln Family Medicine Center and Providence Hospital in Northeast Washington.

Send questions to Consultation, Health Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Questions cannot be answered individually.