Offering help, if not a cure

Vision: Doctors are reporting progress with treatments for macular degeneration, a heartbreaking affliction of aging.

January 17, 2000|By Jonathan Bor | Jonathan Bor,Sun Staff

Macular degeneration, a leading cause of blindness in the elderly, appears to be yielding to new laser treatments that seal off destructive blood vessels behind the retina.

Although doctors caution that the treatments do not offer a cure, they say the therapies have in many cases arrested the downward course of a disease that ordinarily robs people of their sight.

Next month, the U.S. Food and Drug Administration is expected to approve a drug, verteporfin, that is used in concert with a low-powered laser. FDA approval would extend this therapy well beyond the 600 or so patients who have received the treatment in an international clinical trial.

The trial, directed by the Johns Hopkins Wilmer Eye Institute, found that "photodynamic therapy" helped the majority of patients who meet a certain case definition -- a predominance of fast-growing rather than less aggressive blood vessels. When it worked, the treatment kept the condition from getting worse. Some patients even saw their vision improve.

Dr. Neil Bressler, the Hopkins ophthalmologist who headed the study, said about 30 percent of the 200,000 Americans diagnosed each year with "wet" macular degeneration are candidates for the treatment. But patients must be treated early in the disease while they have significant vision to save.

"We can't treat everybody," said Bressler. "But for the person who otherwise would have lost a lot of vision and now has some sight preserved, the treatment is very significant."

The disease is considered one of the most heartbreaking afflictions of aging, sidelining people at an age when they hope to enjoy such pastimes as reading and travel.

'I was afraid'

Judith Mechrez, 62, started to lose her vision two years ago. The retired school secretary, who lives in Israel, was startled to see that the Hebrew subtitles across the bottom of her television screen were running in a "V" formation rather than a straight line.

Within months, objects in front of her nose became twisted and blurred.

"I was afraid -- no reading, no writing, no television, no computer," said Mechrez, who lives near Haifa. "But I'm a fighter, and I didn't let it get me down. I began to search for new ways to do something about it."

She heard about photodynamic therapy from her doctor in Israel, then flew to Baltimore three months ago for her first treatment. Afterward, Mechrez could read two lines on an eye chart that, before treatment, had appeared hopelessly blurred.

"I can see sharper," she said, "but only in the left eye." The right eye was not treated because it had deteriorated too far. On Thursday, Bressler treated the left eye again to dry up some vessels that remained.

Chemical reaction

In a simple office visit, patients receive an intravenous infusion of the drug, which seeks out the abnormal blood vessels. Minutes later, the doctor targets the vessels with a low-powered laser that "turns on" the drug, setting in motion a chemical reaction that seals off the vessels and causes them to dry up.

For more than a decade, doctors have used lasers more crudely

to destroy bleeding vessels. The laser not only burned off the destructive vessels, but also a band of retinal cells in its path. In the best cases, the treatment kept the disease from progressing but left vision more impaired than before.

Ever-widening hole

"Wet" macular degeneration occurs when tiny capillaries grow behind the macula, a small portion of the retina that is responsible for central vision. The vessels can bleed and scar, destroying light-sensing nerve cells and opening an ever-widening hole in a person's sight.

The disease can take years to progress but often moves with lightning speed. Some patients notice a wavy line one day, a huge blur weeks later.

The "wet" disease, which gets its name from the bleeding capillaries, is less common than the "dry" form but more apt to cause blindness. The "dry" disease, which progresses more slowly, is marked by the deterioration of cells responsible for central vision.

As the FDA reviews photodynamic therapy, doctors are reporting exciting progress with

other treatments. In Towson, Dr. Bert Glaser said he has achieved positive results in two-thirds of the patients who received a laser treatment called "feeder vessel" therapy.

Sealing the stem

In this treatment, which does not involve a medication, Glaser shines a laser on tiny vessels -- often just a millimeter long -- that provide blood to the capillaries that are destroying sight. He likens this to sealing the stem that supplies the veins of a leaf. Many patients have only one feeder vessel, he said.

Although he has reported results of about 30 patients, a relatively small study group, Glaser said he has achieved similar results in a larger group of patients but is still analyzing the data. Doctors in Italy and Japan have also reported about the same rate of success in small studies, he said.

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