Taking Aim At A Vision KillerKate Murphy
When Mildred Spinner looks at someone, she sees the outline of a head, but no features. "The face just isn't there," she says. Spinner, a 68-year-old retired personnel director for New York City, has age-related macular degeneration, a disease that affects an estimated 10 million Americans and is the leading cause of vision loss in the U.S. Although there's no cure, improved treatment methods are on the horizon.
The disease affects the macula, a pea-sized region in the center of the retina responsible for visual acuity and color perception. It is what allows you to see a grain of salt, recognize a face, and match your clothes. Beyond middle age, the macula can wear thin and develop holes. "No one really knows why this happens," says Dr. Richard Lewis, professor of ophthalmology at Baylor College of Medicine in Houston. But a likely culprit is free radicals. These highly reactive molecules are manufactured by the body and acquired from such outside sources as ultraviolet light and pollution.
Through a process called oxidation, free radicals may wreak havoc on the delicate cells in the macula. Central vision diminishes while peripheral vision continues to be normal. This condition is known as dry macular degeneration (table). People who suffer from it, like Spinner, have gaps in their vision. Faces blur and colors become indistinguishable. The condition worsens over the years, making driving and reading impossible. Another form of the disease is wet macular degeneration, which often follows the more common dry form. Its progression is much faster, causing severe vision loss in days. The wet form develops from blood vessels that burst through the back wall of the retina. They leak onto the macula and cause wavy vision.
While the vessels can be cauterized by laser therapy, physicians say this procedure is advised in only 10% of cases. Even then, "the laser stops the bleeding but damages the retina in the process," says Dr. Neil Bressler, professor of ophthalmology at Johns Hopkins School of Medicine in Baltimore. Bressler and other researchers are working on what may be a more effective treatment: photodynamic therapy, in which a light-sensitive dye is injected and drawn like a magnet to the abnormal vessels. "We then shine a special light or low-heat laser into the eye. That activates the dye in a way that is toxic to the blood vessels," Bressler says. Preliminary findings indicate that the method doesn't damage surrounding eye tissue. A 600-subject clinical trial is under way, and results are expected by the middle of next year.
Research is also ongoing at Johns Hopkins and Duke University in Durham, N.C., on a surgical procedure called macular translocation. It permanently repositions the macula away from leaking vessels and then uses a laser to stanch the blood flow. The procedure has been performed on some 50 patients. Early results are encouraging, with significant improvement in 20% of the cases, says Dr. James Weisz, a Johns Hopkins researcher. Further out, researchers believe a new class of drugs designed to treat cancer by blocking blood vessel growth to tumors will also work against wet macular degeneration.
Although the disease is incurable, you may be able to prevent it in either form, or slow or stop its progression, by eating green, leafy vegetables. Population surveys suggest the carotenoids lutein and zeaxanthin--abundant in kale and spinach--help protect the eyes. The same may be true of zinc, found in meat, soybeans, and pumpkin seeds. Wearing sunglasses and shunning tobacco are other smart moves, since free radicals generated from smoking and sunlight increase risk of macular degeneration.
You can obtain more information on the malady from the National Eye Institute in Bethesda, Md. (www.nei.nih.gov), or the Association for Macular Diseases in New York (212 605-3719; www.macula. org). And for those like Spinner, whose vision has been irreversibly impaired, there are devices such as magnification software, special lamps, and high-powered spectacles.
Low-vision specialists also suggest compensatory strategies that can help people make the most of the sight they have left. "Improvement is possible in the majority of cases. There's no need to give up hope," says Dr. Michael Fisher, director of low-vision services at Lighthouse Inc. (800 829-0500; www.lighthouse. org), a nonprofit organization for the visually impaired in New York. So don't resign yourself to letting life go by in a blur.