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Laser offers hope for saving sight

A breakthrough therapy is used to treat wet age-related macular degeneration, the leading cause of blindness among people over 65.

By WES ALLISON

© St. Petersburg Times, published May 7, 2000


TAMPA -- The basketball-size image of Eugene Provo's left eyeball clearly showed the culprit: a dark, well-defined nest of blood vessels that was leaking fluid into his retina, blurring his vision and robbing him of sight.

Dr. Mark E. Hammer, a Tampa ophthalmologist, studied the image on the screen one last time and then brought a low-intensity Zeiss laser to bear on Provo's eye and sighted the mass of vessels in his scope. Then he zapped it.

The painless procedure took just 83 seconds but could help Provo keep his sight for years.

"It's still scary, until I see what happens," said Provo, 68, an active, deeply tanned retiree who likes to golf. "I don't want to be blind."

He added, "I can't play real good anyway, so this doesn't help."

Provo suffers from a disease called wet age-related macular degeneration, the leading cause of blindness among people over 65. More than 200,000 senior citizens will get it this year, and Research to Prevent Blindness estimates that 90 percent of them will have severe vision loss.

Until now, doctors have had little power to treat it effectively.

Two weeks ago, the U.S. Food and Drug Administration approved a new laser treatment, called photodynamic therapy, that Provo underwent last week. Although it won't cure the disease and isn't suitable for everyone, the therapy marks the first significant breakthrough in more than a decade. It appears to help about two-thirds of eligible patients stop or slow the damage.

"We've been sort of in neutral for 10 to 15 years, with nothing more to add," said Hammer, a partner in Retina Associates of Florida, which has offices in Tampa and St. Petersburg.

"This is the first major step forward for a disease that's had a very poor prognosis," he said. "In most people, if we're lucky, it keeps the vision about where it is when we catch it."

The macula is a small part of the retina, but it is responsible for central vision. Wet macular degeneration is marked by an explosive growth of blood vessels behind the retina. Those vessels leak fluids that damage the tissue and leave an increasingly large blind spot.

If it occurs in both eyes, it can ruin the ability to perform everyday activities, such as reading, watching TV, paying bills or driving. The onset of the disease can be alarmingly fast, and it can render an eye legally and irreversibly blind within several weeks or months. (The dry version of macular degeneration is much more common, but it progresses more gradually and typically is less severe. There is no cure.)

People with blue eyes and fair complexions seem more likely to develop it, and smoking and poor diet are thought to contribute. The causes aren't clear, but some research suggests the explosion of blood vessels may stem from the body's attempt to repair the natural, time-related wearing out of the macula. While such a rescue effort may help most parts of the body, it devastates the eye.

The concept behind the new photodynamic treatment is not difficult to grasp: A light-sensitive medicated dye, called verteporfin, is injected into a vein in the patient's arm. The dye migrates to the back of the eye and fills those unwanted blood vessels, making them "stand out like a neon sign," Hammer said. The infrared light in the laser activates the medicine, which destroys the vessels.

For years, doctors have used thermal lasers, which generate high heat, to cauterize the leaky blood vessels in wet macular degeneration patients. It worked, but the laser also destroyed healthy tissue and scarred the retina, leaving blind spots behind. Only about one in 10 patients was eligible for that therapy in the first place, and opting for it often meant choosing the lesser evil.

"You'd hope to create a small scar that was better than letting nature take its course," explained Dr. Leonard S. Kirsch, an ophthalmologist at the Eye Institute of West Florida in Largo.

The new photodynamic therapy uses a low-intensity laser that generates no heat, so it doesn't damage healthy tissue. Side effects are few, but patients must stay out of the sun for at least five days or they will burn severely.

The FDA's recent approval was based on the results of a two-year study of 609 patients that showed the therapy helped slow or stop the damage about 67 percent of the time. A small percentage said their vision actually improved.

However, it seems to help only people with a so-called classic case of wet macular degeneration, in which the mass of unwanted blood vessels is clearly defined. The blood vessels also tend to grow back, so the treatment -- which costs from $2,200 to nearly $3,000 -- must be repeated every three or four months, at least for the first year or two.

Medicare has not yet decided to pay for the treatment, although local doctors expect the federal government will act within weeks. Most managed care companies are waiting to see what Medicare does.

And because the photodynamic therapy doesn't restore lost vision, it is especially important that the disease is treated early. Unfortunately, doctors say, many seniors may not realize they have it until the damage is significant.

Provo, for example, noticed vision in his left eye was fading, but he figured he simply needed new glasses. He was diagnosed with wet macular degeneration in October. "It was pretty sudden," he said. "I thought my sight was just changing. After examining me, they found out what was wrong."

Vertepofin, the dye used in photodynamic therapy, is sold by CIBA Vision under the brand name Visudyne, and competing versions are expected to hit the market soon. Although it was approved only two weeks ago, the therapy is widely available throughout Tampa Bay because ophthalmologists and patients had been awaiting it eagerly, and the University of South Florida Eye Institute was one of 200 sites involved in clinical trials.

At the Eye Institute of West Florida in Largo, Kirsch had a waiting list of 35 patients by the time it hit the market.

Doctors hope the new treatment may prompt other advances more quickly, and Kirsch said it may lead to more combination therapies. Researchers also are experimenting with surgery to move the macula to a healthier area of the eye, called macular translocation, as well as surgery to remove the unwanted blood vessels.

Provo said he and his wife, Carmela, had no qualms about trying the therapy, even though it is unproven among the general population. His research indicated it was the best available, and he didn't want the disease to progress.

Provo won't know at least until this week if it worked. Back in their Winter Haven community, several friends and neighbors who face the same problem were expecting a full report on the results.

"Something better may come along in six months -- who knows?" Provo said, as a nurse began running the dye into a vein in his hand. "We signed on the minute we found out it was going to be approved. At this point, I didn't have a choice."

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