Staying Focused

Researchers are exploring new treatments for age-related macular degeneration




Try this: Look at something without looking directly at it. Read this article by focusing your eyes on the other page. Watch television without staring at the screen. Thread a needle while looking across the room.

If you find these tasks difficult, if not downright impossible, welcome to the world of the 15 million Americans afflicted with Age-Related Macular Degeneration, or AMD. There is presently no cure for this crippling disease, and in fact many doctors are still not certain what causes it. But it robs people of their central vision while leaving their peripheral vision intact. In short, it leaves them legally blind.

Normal vision works this way. Light enters the eyeball through the lens, which focuses patterns on the retina, the lining inside your eye. Your brain processes the signals sent from the specialized "rod and cone" cells in the retina, and translates them into words, pictures, whatever you are looking at.

In AMD the macula, an area no larger than a pencil eraser that collects images in your central vision, has deteriorated. The cells are damaged from inflammation, or the macula itself has malformed due to deposits growing beneath it. The result is central vision that is distorted or, in the worst cases, missing entirely. AMD patients see telephone lines with gaps in them, words curving over the page, buildings with squiggly corners, or sometimes just a dark hole in the middle of their vision.

Dr. Alessandro Iannaccone with UT Medical Group's Hamilton Eye Institute explains there are two types of AMD: dry and wet. The dry type is by far the most common, and in many cases doesn't cause a loss of vision. Sometimes it's only evident when an ophthalmologist notices yellowish deposits called drusen on the retina, and researchers are still not in agreement whether drusen leads directly to AMD.

But the wet form, so named because there is actual bleeding beneath the macula, is the kind to worry about. "The wet accounts for the fewest cases, but it is the most devastating," says Dr. Iannaccone, "because once what we call the neovascular membrane begins to form under the retina, it causes disruption of the retinal tissue. The vision loss can be sudden, and severe."

In the past, there wasn't much anyone could do about AMD. Studies had shown some effectiveness from antioxidant vita-mins, especially zinc, though doctors couldn't agree about the exact doses. In fact, UT Medical Group is participating in a major study called AREDS 2 ("Age Related Eye Disease Study") to help determine this. What we do know is that eating leafy green vegetables, such as spinach and collard greens, which contain lutein, also helps preserve vision, as does avoiding bright sunlight.

Still, these have been basic preventive measures. Once someone developed AMD, patients had little recourse but to adapt to a world gradually growing dimmer around them.

That's about to change.

"The good news," says Dr. Iannaccone, "is that we have developed very good treatments that can stop deterioration and even restore part of your vision, which until two or three years ago was a total impossibility."

Some of these treatments are not for the squeamish. One involves a needle injection directly into the eyeball. "That is pretty creepy to say but very easy to do," says Dr. Iannaccone. "You inject substances that block the growth of the membrane that leads to the bleeding and disruption of vision."

Still, he says the real goal is to determine just why these membranes form, instead of trying to stop them once they have already developed.

One technique, still in the experimental stage, involves implanting a porous capsule directly into the white part of the eyeball. Inside this capsule are, as Dr. Iannaccone explains, "a human immortalized line of cells. These came from a child who died many years ago in a car accident, and his parents made his organs available. The cells were harvested, and then" — and this is the fantastic part — "they were genetically modified to never die."

The result, or so the researchers hope, is that these new cells are released inside the eyeball in a constant amount over a long period of time, and will keep any inflammation that causes AMD in check.

"We used to say to our patients, 'The future is coming' or 'We are going to be doing this very soon,'" says Dr. Iannaccone. "But the future is now. It is very exciting because there is a lot of research going on."

For more information about this con-dition, visit AMD.org. In the meantime, take vitamins and remember what your mother always told you: Eat your spinach.

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