SEEING THE LIGHT

When Nancy Wright opted to have a new type of laser eye surgery, it wasn’t a lifetime of nearsightedness but the 1994 Northridge earthquake that convinced her.

Her contact lenses were lost in falling debris, leaving her fumbling in the darkness as she made her way to her 6-month-old son’s bedroom. “It was an awful feeling to not be able to see,” the Northridge resident recalled.

So, despite some initial hesitation, Wright recently had the outer surface of her left eye reshaped by a special laser beam at Cedars-Sinai Medical Center. Moments later, she was awe-struck: She could read a wall clock across the room.

Known as photorefractive keratectomy, or PRK, many ophthalmologists are touting the procedure as something akin to a miracle--although they cautiously avoid using that word. The procedure uses an excimer laser to reshape the surface of the cornea, the eye’s clear protective covering.

Seeing great potential to treat the more than 100 million Americans with bad eyesight, a host of start-up companies, physicians and hospitals have set up laser vision centers--promoting them with ads that proclaim: “Say Goodbye to Your Eyeglasses” or “Live Lens-Free!”

Their aim is to capture a sizable chunk of the roughly $15 billion-a-year U.S. market for vision correction products by convincing patients that laser surgery is a safe and effective alternative to eyeglasses, contact lenses and other surgical-correction methods.

Such promotions already have prompted one warning from federal regulators about misleading and unsubstantiated advertising claims about PRK.

As the U.S. Food and Drug Administration points out, about 5% of patients who have the procedure still need glasses all the time for distance and up to 15% need glasses occasionally, such as when driving.

For the majority of people, though, the procedure results in dramatic improvement in vision, albeit with some minor risks. And that potential is what attracted about 80,000 people to have the PRK procedure performed last year in the United States, a figure that is expected to more than double in 1997.

Although more than 500,000 PRK procedures have been performed worldwide in the last decade, the FDA didn’t deem the laser devices as safe and effective until October 1995. So far, only two publicly held companies, Summit Technology of Waltham, Mass., and VISX Inc. of Santa Clara, Calif., have won the FDA’s blessing for laser devices for PRK use.

The market prospects could improve significantly if the FDA approves VISX’s application to use its laser for treating myopic astigmatism, a defect that causes the eye to improperly focus--a condition effecting 23 million Americans. An FDA advisory panel will take up that issue Tuesday.

Mark Logan, chief executive of VISX, says people with astigmatism will be more motivated to get the PRK procedure than those with only myopia because their vision can’t be perfectly corrected with glasses.

As more people hear about the procedure, experts warn that patients should exercise caution about how and where the procedures are performed.

Although the majority of doctors use the two FDA-approved laser machines, the FDA last July issued a strong warning intended to stop eye doctors from using unapproved lasers, many of them low-cost imports from Europe.

These so-called black box machines can be purchased for $150,000 to $250,000, far less than the approximately $500,000 cost of the Summit and VISX machines. Also, eye doctors who use such machines can avoid paying the $250-per-operation royalties that VISX and Summit require.

“Doctors are trying to save a couple hundred thousand dollars by buying one of these lasers,” Logan said. “We know of at least 30 of these machines. There is no FDA supervision, their reliability is not tested and you don’t know if the machines are calibrated correctly.”

Last March, an Arizona woman filed a medical negligence lawsuit against a Phoenix physician, alleging he used a black box laser to perform eye surgery, resulting in severe vision loss in both her eyes.

Laser eye surgery, a procedure that is performed in the physician’s office and that costs roughly $2,000 per eye, is essentially the latest way that science has found to correct nearsightedness.

In a perfect eye, light is focused close to the retina at the back of the eye, providing a crisp image. But in nearsighted people, the cornea’s shape causes the light to focus in front of the retina, blurring the image.

Glasses and contact lenses correct vision by bending or refracting the light entering the eye so that it strikes the retina precisely. PRK achieves the same result by using an excimer laser to reshape the cornea.

Experts recommend that the procedure not be performed on people under 18, because their vision may still be changing, and that any patient who undergoes the procedure have a record of stable vision for at least a year.

Although the vision improvements are roughly comparable, the PRK procedure differs significantly from the older vision-correction procedure known as radial keratectomy, in which a surgeon uses a knife to make small cuts in the cornea in a spoke-like pattern.

With PRK, an excimer laser, housed in a box about the size of a refrigerator, is controlled by a computer that measures the shape of the eye and sets the power of the laser. It emits short, high-energy bursts of cool ultraviolet radiation to flatten the cornea by vaporizing a microscopically thin layer of tissue.

The entire procedure is remarkably quick, taking five minutes or less, with the actual surgical process lasting just 10 to 20 seconds. Patients say the procedure itself is pain-free, although for a few days after the surgery some patients need painkillers to relieve their discomfort.

One thing PRK won’t do is restore perfect vision for every patient.

Depending on their level of nearsightedness before the procedure, PRK produces 20-20 vision in anywhere from 50% to 75% of patients, according to Dr. Robert Maloney of UCLA’s Jules Stein Eye Institute. And more than 90% of patients achieve 20-40 vision--good enough to drive without corrective lenses--after the procedure, according to clinical studies.

Although none of the 2,000 patients who participated in clinical trials of the procedure reported a decline in vision, about 5% of patients saw slightly worse after the surgery than they had when wearing glasses or contact lenses before the operation.

Immediately after surgery, many patients report a gritty irritation in their eyes that can be uncomfortable but typically lasts only a few days. About 1 in 1,000 patients experience infections during healing, although these are treatable.

Other potential side effects include nighttime glare or “halos” similar to that experienced by many contact lens wearers. Corneal haze, described by one doctor as like looking through a worn contact lens, effects some patients for a few weeks or months after surgery. These side effects disappear in all but a few patients, doctors say.

Compared with radial keratotomy, or RK, PRK produces more accurate vision correction, with less need for follow-up surgery, fewer problems from nighttime glare and more stable results, its proponents say.

“If you have excellent vision after laser surgery, you’ll have it later on,” UCLA’s Maloney said. However, the FDA cautions that the long-term risks of PRK are not entirely known because studies have not followed patients for more than three years.

By contrast, RK patients can experience “quite dramatic” vision changes during the first five years after surgery. But RK patients recover from surgery more quickly--seeing clearly and with less pain than PRK patients. And the procedure is less expensive, costing about $1,500 per eye.

Although some surgeons will perform PRK on both eyes at once, the FDA has specified that only one eye be operated on at a time and that patients wait at least three months between surgeries.

“We don’t think you should burn both bridges by doing both eyes at the same time,” said Dr. James J. Salz, an ophthalmologist at Cedars-Sinai Medical Center.

Salz said it is important to see the results--and any possible complications--of the first eye surgery before going ahead with the second one.