Lasers may fix problems in our eyesight soon Corneal sculpting gains

January 01, 1991|By Richard Saltus | Richard Saltus,Distributed by Universal Press Syndicate

In five years or so, the offices of eye doctors may well be crowded with people who have no interest in glasses or contact lenses. Instead, they'll be queuing up to have a laser beam etch a permanent vision correction into their eyes.

With eyelids propped open and eyeballs anesthetized by numbing drops, they'll face the laser as it fires as many as 200 pulses of ultraviolent light with a rapid snapping sound. In a minute or less, it will have vaporized a thin layer of tissue from the cornea, the eye's transparent, lenslike covering, leaving it flattened by just the amount needed to refocus the patient's vision.

It's called laser corneal sculpting, and it could be approved for routine use by the mid-1990s.

Researchers say they haven't seen any major roadblocks in early testing. In fact, they say that laser sculpting appears to have corrected the nearsightedness of about a hundred patients -- including some whose vision was so poor they couldn't read the big "E" on the top line of any eye chart without lenses.

Still, there are enough uncertainties that the government is requiring each maker of laser equipment to test the treatment on 700 patients and to monitor their eyes for two years. Only one eye of each patient is to be sculpted, in case unexpected problems turn up.

Researchers have noticed that for months after sculpting, the cornea is thickened as it heals. They'll check how well the vision corrections hold up under those changes. There are also questions about whether the laser will always leave patients with completely clear vision; a temporary haze has been seen on the corneas or most test subjects.

Experts are cautious, too, because of the less than spectacular history of a similar, but cruder, method of corneal reshaping called radial keratotomy. Introduced more than a decade ago, radial keratotomy cuts four to eight slits in a starburst pattern around the cornea's edge. This weakens the tissue so that it flattens in the center, though just how much has proven hard to predict. Many patients don't end up with precisely the correction hoped for.

Since the method involves incisions that go 90 percent of the way through the cornea, there's a risk of infection and perforations. And some patients are bothered by glare, apparently as a result of imperfect healing of the deep incisions.

Proponents of laser sculpting say the "cool" light from a excimer laser can vaporize less than one-tenth the thickness of the cornea, barely heating or disturbing surrounding tissue. They claim its deftness greatly minimizes they eye's healing reaction.

"Our patients are right on the money: 20/20 vision or so close t it that they don't wear glasses or contacts," says Marguerite McDonald, a researcher at Louisiana State University who works with one of several companies hoping to market an eye-sculpting machine. Those results were for seven patients whose original eyesight measured from about 20/100 to 20/400 (legally blind), a range encompassing most of the nation's 60 million nearsighted people.

McDonald acknowledges that laser sculpting is now les effective for the more severely nearsighted because they need deeper etching, which leads to less predictable healing. Still, surgeons say that someone who's worn thick "Coke-bottle" glasses all his life may be thrilled at just being able to wear thinner lenses.

Skeptics argue that laser sculpting amounts to major surgery o healthy organs, and that it should not be approved until it's shown to be flawlessly effective and safe. Cost is another hurdle: about $1,500 per eye, unlikely to be covered by insurance.

Even if the government approves laser eye sculpting in the next few years, farsighted and astigmatic individuals won't be tossing out their eyeglasses and contact lenses right away. Their eyes would need to be sculpted using far more complex techniques that are in only the early stages of development. What's more, many people simply will choose to avoid any operation on their eyes, especially as contacts improve.

But vision and marketing experts say that still leaves millions of others -- athletes, pilots and police officers, for instance -- who'd prize a vision correction that can't be lost or knocked off, as well as ordinary myopes who'd just prefer the convenience.

Says ophthalmologist Carmen Puliafito of the Massachusetts Eye and Ear Infirmary: "This could become the most common procedure in medicine."

Excerpted from In Health Magazine

Distributed by Universal Press Syndicate

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