Conquest of Cataract

For more than 3,000 years, doctors were balked in their efforts to restore anything like normal vision to elderly eyes clouded by cataracts. In modern times they have been able to cut into the eyeball, remove the cataract-clouded lens, and try to make up for the loss of the lens by spectacles. But they have not dared to insert a substitute in the eyeball. Now a British eye surgeon reports a way to do just that: a carefully ground lens made of plastic is slipped into the eyeball during the operation and stays there.

The lens in the normal eye is a jelly-filled capsule of a tough material resembling Cellophane. A cataract is a clouding of this normally transparent lens (see diagram); as the clouding gets denser, less & less light gets through to the retina. Sometimes the whole lens is removed, sometimes only a part, with the clouded jelly. In either case, external lenses (i.e., special glasses) with limited focusing range have been necessary.

22 out of 25. In the Lancet, Dr. Harold Ridley, London surgeon, describes the ingenious new technique for slipping a plastic lens into the eyeball. Only the front part of the lens capsule, with the jelly, is removed; the back part of the capsule is allowed to remain as a sort of frame to keep the artificial lens from drifting farther back into the eyeball. The plastic chosen for the job (Perspex, similar to the Plexiglas used for airplane windshields) is only half as heavy as glass and is not likely to sink.

Dr. Ridley has put such lenses into 25 eyeballs. The first two were failures because the scientists imitated nature too closely and made the artificial lens as thick as the ordinary lens. That, it turned out, was too strong. Now they make the lenses thinner. Another failure occurred with an enfeebled man of 75 whose wound did not heal. But Dr. Ridley reports that in 22 cases, the operation appears to be successful. One patient has worn his built-in lens for two years without mishap.

"I Can See Clearly." Twenty operations were done long enough ago to allow the vision in the repaired eye to be measured. Two of these have better than "normal" visual acuity--i.e., they can read letters at 20 feet, where normal calls for 16 feet. Five have normal acuity, and five more can read at 20 feet what normal eyes can read at 30. The other eight taper off to 20/120. The plastic lenses are focused for distant vision (20 feet to infinity); for reading or playing cards, the patients need glasses.

"It is a new experience," says Dr. Ridley, "to hear a cataract patient remark at a post-operative dressing, 'I can see the faces of all you gentlemen quite clearly.' " U.S. eye specialists are amazed by the news from London. If the plastic lenses stand up for five years without trouble, they say, it will be the greatest advance in cataract treatment since the invention of eyeglasses.

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