By Martha A. Simpson, D.O., M.B.A.
Associate Professor of Family Medicine
Ohio University College of Osteopathic Medicine

AMD CAUSES CENTRAL VISION LOSS, BUT SIDE VISION REMAINS INTACT

Question: I am in my early 60s. My doctor told me that I should be checked for macular degeneration at least yearly. Can you tell me more about this? What would the symptoms be? Do I really need to go the eye doctor for this?

Answer: Age-related macular degeneration (AMD) is the leading cause of central vision loss in people over 65. This progressive disease affects an area called the macula lutea, which is located in the center portion of the retina in the back part of the eye. The retina is where the eye’s light-sensing cells are located. With AMD the cells in the macula stop working and die. It is thought to be due to genetic and environmental causes.

The onset is usually after 50, with 15 percent of people in their 90s having AMD. Over 2 million new cases are diagnosed every year. It is more common in white women over 65 who smoke. It has a slow onset and usually involves both eyes. There are two types of AMD, dry and wet.

Dry AMD is the more common type, but fortunately, it’s less debilitating. In dry AMD the process that removes normal debris in the retina via the small blood vessels in the back of the eye stops working. No one knows why. There are no real treatments available, but eating green leafy vegetables, daily doses of antioxidants and zinc, and avoiding bright sunlight all seem to help slow the progress.

Wet AMD accounts for about 15 percent of all AMD cases but causes 80 percent of the disability. In wet AMD, there is an overgrowth of newly formed blood vessels in the eye. These new blood vessels tend to be very fragile and often leak blood and fluid into spaces around the light-sensing cells.

There are some drug treatments available for wet AMD. One of these is pegaptanib. It is administered by first numbing the eye with an anesthetic and then injecting the drug into the eyeball. Pegaptanib has been shown to halt the abnormal blood-vessel growth that causes this type of macular degeneration.

Another treatment is photo-dynamic therapy. It involves the use of lasers to destroy the extra blood vessels. However, it can only be used on about 30 percent of those with macular degeneration.

Regular checkups from your eye doctor are important at detecting AMD, especially the dry type that usually develops gradually over a number of years. Talk to your doctor about how often you need to have these checkups. Wet AMD, however, tends to come on very quickly. You should see your eye doctor immediately if you have any of the following symptoms: a sudden, rapid loss of vision; a new blank or dark spot appears in the center of your vision; straight lines appear wavy or curved; or objects change size or shape or appear distorted.

AMD, whichever type, causes loss of central vision -- things right in front of you. Your side, or peripheral, vision remains intact. Though macular degeneration is a serious disability, it is not as debilitating as other causes of blindness that result in a total loss of vision.

If you develop AMD, you may have to discontinue some activities that require very sharp vision, such as driving, threading a sewing needle, or reading fine print. However, with the use of visual aids and low vision rehabilitation programs, most people with AMD can lead full, independent lives.

Family Medicine® is a weekly column. To submit questions, write to Martha A. Simpson, D.O., M.B.A., Ohio University College of Osteopathic Medicine, P.O. Box 110, Athens, Ohio 45701, or via e-mail to readerquestions@familymedicinenews.org. Medical information in this column is provided as an educational service only. It does not replace the judgment of your personal physician, who should be relied on to diagnose and recommend treatment for any medical conditions. Past columns are available online at www.familymedicinenews.org.