Spectacle Within the Eye

Lens implants bring better vision to cataract patients

Charles de Gaulle wore them. So did Impressionist Claude Monet and myriad others. Their glasses, as thick as Coke-bottle bottoms, were and still generally are the unmistakable emblem of millions of people who have undergone surgery for removal of cataracts--clouded lenses of the eyes. Of the 400,000 patients who had such operations last year, the majority were 65 or older. Most now wear the distinctive--and somewhat unflattering--spectacles. But more than 50,000 of them have no need for special glasses; they have undergone a controversial new procedure--the implanting in the eye of a tiny artificial "intraocular" lens.

For carefully selected patients, many leading ophthalmologists are now replacing clouded human lenses with such permanent plastic substitutes; the doctors say the operation carries no more risk than the conventional surgery used to remove cataracts. What is more, the operations seem to have been remarkably successful. Of the patients who received implants last year, 85% have essentially normal vision now.

This is welcome news for the aged, for whom cataract removal is one of the most common operations, and one of the most ancient. Cataracts can, of course, form at any stage in life as a result of injury, inflammation or disease, and may even be present at birth. But they are, like wrinkles and gray hair, most commonly a natural byproduct of the aging process. The normal lens of the eye, located behind the iris, consists of clear protein encased in a capsule. Cataracts are changes in the molecular structure of the lens protein that cause it to lose its natural transparency and gradually become opaque.

In advanced cases, the patient is left nearly blind. As Hollywood Screenwriter Leonard Spigelgass, 68, who has had two lenses implanted, recalls: "Your lenses turn into agate, and you're forced to look through stone." Removing these shadowed lenses allows light to enter the eye but creates another problem. The lens of the normal eye focuses the light rays; without it, vision becomes hopelessly blurred. Under such circumstances, the patient has only a few options: thick glasses, contact lenses or the artificial lens implant. The special spectacles restore vision to normal levels but, in the process, magnify images by 30% and leave the patient with limited peripheral vision. Contact lenses produce less distortion and permit peripheral vision but can be irritating to the eyes, difficult to insert and easy to lose--especially for elderly or arthritic cataract patients who are practically sightless without their lenses.

The lens implant provides vision almost matching that of the natural lens without these troubling side effects. Moreover, the plastic lenses, available in a variety of designs and optical powers, can be chosen before implantation to correct other vision problems, including near-and farsightedness. By picking the correct power of the implant lens, New York Medical College Ophthalmologist Miles Galin, who has done more than 2,000 implants, is often able to reassure patients before surgery: 'You'll probably see better without glasses than you did before the cataract developed."

While lens implants are a centuries-old idea, the present operation traces back to a chance observation by a British eye surgeon during World War II. Ophthalmologist Harold Ridley noticed that when fragments of plastic from fighter-plane windshields shattered by enemy gunfire lodged in the eyes of pilots, they caused no inflammation. Using the same plastic to fashion tiny lenses, Ridley began performing the first implants. Though pioneering efforts failed more often than not, improved surgical techniques and lenses now make the operation a relatively simple, if delicate, procedure, often performed under only a local anesthetic.

Peering through a microscope, the surgeon makes a tiny, curved incision at the junction of the cornea (the clear, watch crystal-like front of the eye) and the sclera (the white outer coat of the eye). Through this slit, the natural lens can be removed in various ways. Often a probe cooled with liquid nitrogen is inserted to touch the lens, which promptly freezes to it. Then the probe is withdrawn, bringing the lens along. Another technique uses ultrasonic vibrations to break the hardened lens into tiny particles that are sucked out through the incision with a hollow needle. The plastic substitute is then inserted, leaving the inner eye exposed for as brief a time as 30 seconds.

The placement of the implant depends on the type of lens that the surgeon has selected: one design fits in back of the iris, another in front. But the most popular, developed by Dutch Ophthalmologist Cornelius Binkhorst in 1957, is clipped directly onto the iris itself with tiny, bent nylon tabs.

Often the operation takes no more than 30 minutes. Some patients can even leave the hospital shortly after surgery and need wear a patch over the eye for only one day--a far cry from 25 years ago, when cataract surgery meant ten days in a hospital bed with the patient's lead held stationary between sandbags.

Critics warn that implanted lenses have not yet been tested by time--the procedure has been widely used for less than ten years in the U.S.--and that the lenses sometimes slip and may cause irreparable damage to the eye, even blindness. But for tens of thousands of elderly patients, that future risk is less important than their present gain--they can see again, one welcome physical change in their twilight years.

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