Related topics: •  Aging and Vision Care: The Eyes Have It •  Bilberry •  Cataract •  Eye Problems •  Quiz: Seniors, How Much Do You Know About Your Eyes?

Most people have heard about glaucoma and cataracts, but there's another eye disease that senior citizens should know about, especially those of European descent. This is macular degeneration, or damage to the macula, an ultrasensitive part of your retina that gives you sharp focus in the center of your vision. If you develop this condition, you may have trouble driving, reading, recognizing people, or other activities that require fine central vision. You may eventually experience major vision loss. Macular degeneration affects more than 10 million Americans and is the leading cause of legal blindness in older Americans. It's important to know, though, that macular degeneration almost never causes complete blindness. In fact, most patients who have the disease can continue to live productive and independent lives.

There are two basic types of macular degeneration, known as "dry" and "wet." About 90 percent of all cases are the dry sort, in which the macula has simply grown thin over the years. The dry form progresses very slowly and may never interfere with a person's life. Many people simply notice that their vision fades a bit when they read. The wet form of macular degeneration is much more serious. In this case, abnormal blood vessels grow beneath the retina and start to leak, creating a pool of blood and other fluids that damages your retina and blocks your vision. Occasionally, a dry case can turn wet. If you have the dry form, see an ophthalmologist immediately if your vision suddenly worsens.

Whether a case is dry or wet, the early symptoms of macular degeneration are the same. Schedule an appointment with an ophthalmologist promptly if you notice any of the following signs:

•Vision becomes fuzzy or blurry

•Straight lines, such as sentences in a book or sides of buildings, start to look wavy

•Blank or dark spots show up in the center of your vision

Age is by far the biggest risk factor for macular degeneration, although some rare forms of the disease can strike at any age. The disease sometimes develops during a person's forties or fifties, but it's much more common in people over 60. Macular degeneration also runs in families, so be on guard if your parents or siblings had the condition. It's also more common in women, smokers, and people with light-colored eyes. The disease is rare among nonwhites. There's no strong evidence that excess exposure to ultraviolet rays can cause macular degeneration, although a lifetime of sun worship without eye protection will definitely increase your risks of cataracts.

A simple at-home test can help you detect macular degeneration before symptoms set in. You'll need a special card that features a grid of straight lines with a dot in the center. This card, called a Yannuzzi card, is available from your doctor, and any person older than 50 should have one. Here's how you use it: With your face 14 inches away from the card, close one eye and look at the dot. (Many people age 50 and older will need to use reading glasses.) If you have macular degeneration, the lines may look wavy, discolored, or otherwise distorted.

Your ophthalmologist will have to look at your retina to confirm a case of macular degeneration. People with the dry form of the disease will have small, round marks called drusen on their macula. If you have the wet form, the ophthalmologist will be able to detect blood vessels growing under your retina.

There's no proven remedy for dry macular degeneration. The wet form of the disease can be treated with laser surgery, photodynamic therapy, or injections. Laser surgery, which destroys the leaky blood vessels that damage the macula, works best if the vessels aren't directly beneath the center of the retina. Studies by the multicenter Macular Photocoagulation Study Group (MPSG) found that about 25 percent of surgery patients in this best-case category suffer severe vision loss within a year, compared with 40 percent of untreated patients. Unfortunately, blood vessels grow back in about half of all treated patients within one year of surgery. If you have vessels centered beneath your retina, laser surgery will inevitably destroy vital tissue while it wipes out the vessels.

In photodynamic therapy, a drug injected into the arm is attracted to the damaged blood vessels in the eye. Next, a light is aimed at the eyes, activating the drug and causing it to destroy the blood vessels. Unlike laser surgery, photodynamic therapy doesn't harm healthy tissue. The procedure takes about 20 minutes and can be done in your doctor's office. Since the drug is triggered by light, you'll need to avoid exposure to sunlight or bright indoor light for five days after treatment. As with laser surgery, the procedure may need to be repeated as more leaky blood vessels develop.

While laser surgery and photodynamic therapy will not restore lost vision, injections with new drugs can block the growth of the abnormal blood vessels that lead to vision loss. Called Anti-VEGF therapy, this drug treatment can help slow vision loss and in some cases improve sight.

Today's treatments leave much room for improvement, and researchers across the country are working to answer the call. Within a few years, patients may be able to choose from a variety of new medications, surgeries, or radiation treatments that can stop macular degeneration without damaging the eye.

Nobody knows for sure, but some experts believe certain nutrients can protect your eyes from macular degeneration. If you're at high risk for the disease or already have the dry form, changing your diet and including nutritional supplements may help protect your vision. A 2003 study published in Archives of Ophthalmology suggests that 20 percent of people at high risk for advanced macular degeneration may be able to avoid it for the next five years if they take special high-dose zinc and antioxidant supplements.

However, there are conflicting reports about the benefits of nutrients and vitamins. A Harvard study of over 21,000 men found that regular intake of vitamin C, vitamin E or multivitamin supplements didn't significantly reduce the risk of macular degeneration. In fact, vitamin C supplements seemed to slightly increase the odds of the disease. If you want to play it safe, get your vitamins by loading up on leafy greens.

The most promising nutrients for preventing macular degeneration seem to be lutein and zeaxanthin, carotenoids found in yellow corn and dark green, leafy vegetables. These pigments are also abundant in the eyes, and they seem to help protect the retina from damage. A study by the National Institutes of Health found that people who ate spinach or collard greens five or more times each week were almost 90 percent less likely to develop macular degeneration.

Green vegetables are undoubtedly good for you, but it may not be wise to load up on lutein or zeaxanthin supplements. Carotenoids can have unwanted effects in large doses; for instance, too much lutein can block the effects of lycopene, another carotenoid that may help prevent lung cancer and prostate cancer. In general, you're better off getting your protection in natural forms.

-- Chris Woolston, M.S., is a health and medical writer with a master's degree in biology. He is a contributing editor at Consumer Health Interactive, and was the staff writer at Hippocrates, a magazine for physicians. He has also covered science issues for Time Inc. Health, WebMD, and the Chronicle of Higher Education. His reporting on occupational health earned him an award from the northern California Society of Professional Journalists.

References

First published June 13, 2000
Last updated April 19, 2007
Copyright © 2000 Consumer Health Interactive

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