New Treatment May Help stem Vision Loss from Macular Degeneration

AGE-RELATED macular degeneration (AMD) is the leading cause of severe vision loss in older Americans. And "wet" macular degeneration, in which new blood vessels grow underneath the retina of the eye and lead to leakage and scarring, is the worst kind of all--causing 90 percent of the reduction in eyesight associated with the disease. The damage it heaps on the delicate retinal tissue leads to a loss of central vision, making it difficult if not impossible to read, watch television, or even recognize friends and relatives. "People with really bad macular degeneration can't see the big `E' on the eye chart," says Peter Kaiser, MD, an ophthalmologist with the Cleveland Clinic Foundation in Ohio.

Now, a new type of combination drug and laser therapy called ocular photodynamic therapy, approved by the Food and Drug Administration in April, offers hope to people with wet macular degeneration. In a recent study of 600 patients in the US, Canada, and Europe, 61 percent of those given the therapy saw their vision improve or at least remain stable, compared with 46 percent of patients who received placebo, or "dummy," treatment. The results were even better for a subgroup of patients with predominantly "classic" wet AMD, in which the abnormal blood vessels grow in a particular pattern. Almost 70 percent of the treated patients retained their current level of vision, versus 39 percent of patients on placebo.

The treatment, which is performed on an outpatient basis, is a two-step process. First, a drug called Visudyne is injected into a patient's arm. A 5-minute waiting period follows, during which the medication makes its way to the eye--and is readily absorbed there by the abnormal blood vessels. Next, a doctor shines a "cold" (non-heat-producing) laser directly into the patient's eye to activate the drug. The resulting molecular activity destroys the abnormal blood vessels and stops the leakage--thereby stemming further damage to the retina.

The new treatment is a real breakthrough for a condition for which no satisfactory treatment had existed before. In the past, doctors used a "hot" laser to cauterize leaky blood vessels in some patients. But the treatment also caused damage to normal retinal tissue and, sometimes, further loss of vision. Ocular photodynamic therapy "kills the blood vessels from the inside, without damaging the retina or other surrounding structures," says the Cleveland Clinic Foundation's Dr. Kaiser.

Unfortunately, the treatment can't help people who have the "dry" (less severe) form of the disease. And, as shown in the multi-country study, it doesn't appear to work as well in people whose new blood-vessel growth isn't predominantly of the "classic" pattern.

Even people for whom the procedure does work may have to come back for a series of several treatments until all of the leaky blood vessels have been permanently sealed off. It's not likely to improve vision, although this has happened in some people; Dr. Kaiser tells his patients that the treatment is "mostly to stabilize what vision they have left" as well as "prevent futher loss of vision."

Because treatment with Visudyne works best to stabilize vision before too much is lost, that's even more reason to get your eyes checked regularly by an ophthalmologist for signs of macular degeneration. Many eye doctors recommend that patients check their own vision at home using a grid like the one at the left below.

The grid, below left, is a tool for monitoring your central visual field. It makes it possible for you to tell if there are disturbances in your vision (simulated in the grid at the right) caused by changes in the retina. That could be a sign of wet macular degeneration.

Here's how to use the grid to the left:

sit in an area with good lighting, and hold the grid at eye level at a comfortable distance.
If you wear glasses, keep them on, but cover one eye completely.
Stare with your other eye at the central dot on the grid. At the same time, observe the pattern of vertical and horizontal lines on the chart.
Repeat the test with the other eye.
Make an appointment with your ophthalmologist immediately if you experience any of these changes:

blurring
distortion or curvy lines
holes or spots in some areas of the grid
How the grid might look if you have macular degeneration

[*] Grids and instructions are from the American Academy of Ophthalmology's website at http:/www.eyenet.org.

ILLUSTRATIONS (BLACK & WHITE)

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