Age-related macular degeneration (AMD) is the leading cause of severe vision loss among older people. Although the disease is not yet curable, promising new therapies in the research pipeline may be available soon.
Source: Adapted from Knowing Your Options: The Definitive Guide to Choosing The Medical Treatments, Reader’s
What is macular degeneration?
Roughly the size of an eraser on a pencil, the macula occupies the center of the retina in your eye. Despite its small size, it is responsible for the sharp, high-definition, central vision that allows you to read, drive, recognize faces, and distinguish fine details. When you have macular degeneration, the macula in one or both eyes has irreversibly deteriorated over time. Your vision may become blurred. A blind spot may develop in the center of your visual field, and many fine-detail activities, such as reading and writing, may become difficult or impossible to do with accustomed ease. Your peripheral vision remains intact.
Who is at risk for macular degeneration?
No one knows what causes age-related macular degeneration (AMD), but bysome estimates, about one-quarter of people over age 65 and fullyone-third of those over age 80 show evidence of this condition. Nearly90% of those with AMD have the dry (or nonexudative or atrophic) form,in which the light-sensitive cells in the macula slowly decay andyellow spots of fatty deposits called drusen appear on the macula (seeillustration below). Dry AMD is the less severe of the two forms,progressing slowly and sometimes stabilizing for a time. You might noteven notice symptoms of vision loss, especially if it is restricted toone eye and your “good” eye compensates.
In the less common form, called wet (or exudative or neovascular) AMD,fine blood vessels grow beneath the retina, leaking and damaging themacula. Wet AMD progresses more quickly than dry AMD and causes moresevere vision loss, sometimes within days or weeks. Left untreated, wetAMD can lead to legal blindness (defined as vision of 20/200 or worse)although not to total blindness. About 15% of people with dry AMDdevelop wet AMD.
Although they rarely do, young people can develop macular degenerationdue to a genetic disorder or as a drug side effect. Most often, though,the condition is related to the aging process. Your odds of getting AMDare higher if you have a family history of it, or if you’re female,white, and have light-colored eyes.
Other risk factors for macular degeneration include exposure to smoke and direct sunlight andconditions such as high blood pressure, high cholesterol, or obesity.
Treatment for macular degeneration
The cause of AMD is still unknown. There is no cure for it at present and no sure way to reverse the vision loss that may result. There are no proven remedies for dry AMD, and there are treatments for only certain cases of wet AMD. Still, there is plenty of cause for optimism. AMD is currently a hot area for research, especially as the population ages and the disease becomes more prevalent. There is also growing evidence that diet and nutritional supplements can make a real difference. Further, macular degeneration does not cause total blindness. In fact, dry AMD causes no serious vision loss in most people. Even if you have the wet form, with its more severe ramifications, you’ll still be able to see well enough to perform most activities of daily living.
Because having dry AMD puts you at risk for developing wet AMD, you’ll need regular vision tests. If wet AMD is caught early, the chances are better that it can be halted with laser surgery or a treatment called photodynamic therapy.
Medications for macular degeneration
A medication called verteporfin (Visudyne) is injected into your arm and absorbed by the abnormal blood vessels in your eye. Then photodynamic therapy is performed. In clinical trials using Visudyne, 67% of people found their vision loss halted after this therapy.
Even though effective treatments for AMD are scarce, there is much you can do on the lifestyle front to preserve the vision you have:
- Monitor your eyes. Your best defense against vision loss is to act promptly. See your eye doctor regularly, and monitor your eyes at home with an Amsler chart, a piece of paper with a grid of black lines (ask your doctor for one). Cover one eye at a time so you can test each eye individually. If straight lines look wavy or there is a gap in the lines, call your eye doctor at once.
- Eat your fruits and vegetables. The old saw that carrots are good for the eyes is true. Studies have shown that a balanced diet rich in fruits and vegetables—especially those containing carotenoids such as beta-carotene and lutein—can help preserve eye health. This means eating foods of green, red, orange, or yellow hue (tomatoes, corn, squash, kiwis, oranges), as well as green leafy vegetables.
- Cut down on fat. A high total fat intake is associated with increased risk of AMD. This is especially true of animal fats but also includes the omega-6 fatty acids (found in vegetable oils). There’s one exception: The omega-3 fatty acids in salmon, mackerel, tuna, and other fish may help preserve your vision.
- Keep up your health. High blood pressure is associated with AMD. Diabetes can also affect eye health. If you have it, continue your efforts to keep your blood sugar levels under tight control.
- Don’t smoke. People who smoke are at a greater risk for AMD, and more likely to respond poorly to laser surgery.
- Avoid bright sunlight. When you go outdoors, wear sunglasses that absorb all UVA and UVB radiation, and shade your eyes with a wide-brimmed hat.
Related Procedures for Macular Degeneration
If you have wet AMD, your doctor may use laser surgery to seal the leaking blood vessels under your macula. This outpatient procedure, known as laser photocoagulation, takes about half an hour and requires only local anesthesia. However, it is recommended for only a small percentage of people with wet AMD. Leaking vessels the doctor can’t see are called occult (hidden). Laser photocoagulation is not an option for people who have them, nor is it advised if the leakage has reached the central part of the macula (called the fovea), an area the laser would damage.
The procedure works best on newly formed, well-demarcated vessels clustered in a specific area. To locate the vessels, your doctor will use a procedure called fluorescein angiography, in which a dye called fluorescein is injected into your arm and circulates through your eyes. If you have this treatment, the laser will cause some vision loss, but less than if you were completely untreated. Such surgery can halt the progress of wet AMD, but can’t restore lost vision, and there is at least a 50% chance that the disease will recur. If this happens, it can be treated with more laser surgery.
In photodynamic therapy, a drug is injected, then activated by a laser to seal the leaking vessels. This process has an advantage over standard laser surgery: The laser in photodynamic therapy uses much less heat, and so is less likely to damage healthy eye tissue. Like laser surgery, however, photodynamic therapy does not restore vision or cure wet AMD. It may need to be repeated. It is approved only for patients whose new blood vessel growth is deemed “predominantly classic,” or plainly apparent, which is true of 40% to 60% of patients.
Alternative Therapies for Macular Degeneration
In some people, nutritional supplements can help prevent AMD from progressing. Daily doses higher than you can get from diet alone or from ordinary multivitamins are recommended: 80 mg of zinc picolinate, along with the antioxidants vitamin C (500 mg), vitamin E (400 IU), and beta-carotene (15 mg). You should also take copper (2 mg) to counteract the tendency of large doses of zinc to interfere with copper absorption. Bausch & Lomb offers a whole package of vitamins and minerals as Ocuvite PreserVision, the supplement used in the AREDS trial. If you are interested in this nutrient mix, talk with your doctor: Not everyone can benefit from it. It doesn’t prevent AMD, and it doesn’t keep early stages of the disease from progressing.
Questions for Your Doctor
- How often should I have the status of my AMD re-evaluated?
- What are some signs that my AMD might be worsening?
- Am I a candidate for laser surgery or photodynamic therapy?
Living with Macular Degeneration
If you’re living with AMD, here are a few quick hints to help you take control:
- Keep up with the news about AMD. Researchers are currently testing and developing new treatments that may turn out to be just what you need. Ask your doctor about clinical trials of therapies that might help your particular case.
- Don’t be afraid to use your eyes. Your normal activities won’t make your AMD get worse. So go ahead and read, watch television, and use a computer as much as you want.