Vitamins may help stem loss of vision

Q: My mother was just diagnosed with macular degeneration. What can she do to help preserve her sight?

A: Macular degeneration (also called age-related macular degeneration, or AMD) is a leading cause of vision loss in Americans 60 and older. Located in the center of the retina, the macula is responsible for sharp central vision, which people need to distinguish objects, read and drive.

People with AMD often develop blurred or distorted vision and can't clearly see objects directly in front of them. Over time, they may develop a blind spot in the middle of their field of vision that increases in size.

The disease occurs in two forms: dry and wet. The dry form is the most common. It involves a breakdown or thinning of retinal tissue and the decay of cells in the macular area of the retina. Dry AMD may affect only one eye at first, causing gradual distortion and blurring of the central sight. But the second eye also often is affected, and in some cases, dry AMD can lead to severe vision loss.

Wet AMD is less common but often progresses much faster. In this form of the disease, abnormal blood vessels grow in the retina, impairing vision. A new drug injected into the eye can slow this process and preserve vision. Photodynamic therapy using an intravenous drug is another option.

As with many diseases, the risk increases with age. People in their 50s have only a 2 percent chance of developing AMD. Yet that risk jumps to 30 percent in those older than 75. Women (who tend to live longer than men) get the disorder more often, as do people with a family history of the disease.

Other than age, factors that increase a person's risk for AMD include cigarette smoking, exposure to bright sunlight and UV radiation. Having hypertension, high cholesterol, coronary artery disease, light-colored eyes and farsightedness also increases a person's chances of getting AMD.

While there is no surefire way to put the brakes on AMD, your mother can take steps that may help. If she smokes, she should quit. Wearing hats and sunglasses that block the sun's blue wavelengths also may provide some protection. Several years ago, a major study found that supplements containing certain vitamins and minerals could delay the progression of AMD by 25 percent in people with an advanced form of the disease.

The Age-Related Eye Disease Study, done by the National Eye Institute, used 15 milligrams of beta carotene along with 500 milligrams of vitamin C, 400 IU of vitamin E and 80 milligrams of zinc oxide. Since then, "healthy vision" vitamins have become popular. A note to those worried that they might develop AMD: While these supplements seem to benefit people already diagnosed with the disease, there's no evidence that taking them will protect you from getting it in the first place.

Because dry AMD progresses very slowly, people usually are able to manage well in their daily routines. If the condition worsens, special low-vision aids can help. Examples include magnifying lenses or closed-circuit televisions that "read" regular print and then display it enlarged on a monitor.

Some magnifying lenses can be incorporated into the lens of a pair of prescription glasses and used for reading or detail work. Special lenses that work like miniature telescopes can be mounted on a pair of glasses for use while driving or watching a movie. Glasses with filters or stand-mounted magnifiers containing a light source may help with excessive glare or problems with distinguishing between light and dark.

On the computer, software programs can make the text on a monitor larger or more legible to people with vision problems. Electronic "talking" watches, alarm clocks and calculators let people rely on their hearing rather than their vision. Listening to audiobooks is another popular option.

Other inexpensive, low-tech vision aids include large-print versions of playing cards, bingo cards and push-button telephone pads. And many books and newspapers come in large-print editions.

The Harvard Medical School Adviser is researched and written by the faculty and staff of Harvard Medical School. Visit www.health.harvard.edu/adviser.