Serendipity and the Origin of the Lens Implant in Cataract Treatment

In 1942, a young British flight surgeon, Ridley, made an outstanding discovery that was to shape the future of cataract treatment. Cataracts result from the clouding of the lens of the eye, which leads to blurred vision. As with the lens of a camera, the lens of the eye functions by focussing light rays onto the retina at the back of the eye, which then transmits this visual information to the brain. For the light to pass through and reach the retina, the lens must remain clear. Cataracts result when the natural lens of the eye becomes cloudy; they are not the product of a growth or the accumulation of film over the eye.

While examining injured fighter pilots, Ridley noted that when plastic slivers from the shattered windshield of an airplane cockpit entered the eye, some pilots had a severe reaction, whereas other pilots had no reaction at all. At the time, the accepted belief was that any foreign material entering the eye would cause a severe reaction until it was removed. Ridley wanted to understand why some pilots showed no reaction to the presence of a piece of plastic in their eye. Further investigation led him to realize that it was only the pilots of Spitfires who did not suffer any complications, whereas pilots flying all other British fighter planes--including captured German pilots flying Messerschmitts--were all severely affected. The young surgeon then discovered that Spitfire plastic came from a different company, ICI, that produced a type of plastic material, polymethyl methacrylate, which could be tolerated by the human eye.

When the war ended in 1945, Ridley turned his attention to cataract surgery. Treatment at the time involved removing the diseased cataract lens and giving the patient thick, heavy glasses that limited their peripheral vision and magnified objects by 30 %. Ridley decided that a better technique for cataract treatment would be to replace the human lens with a lens made of the plastic that he had discovered during the war. On 19 November 1949, at St. Thomas's Hospital in London, he performed the first lens implant on a cataract patient.

Today the treatment of cataracts still relies solely on surgical techniques; there is no medication or diet that can stop a cataract once it has begun to form. A cataract may develop rapidly over a period of a few months or it may grow very slowly over several years. Typically, this process only occurs in a single eye, although eventually, often after months or years, a cataract may develop in the second eye. Most cataracts are related to aging, although they may also be congenital, the result of a medical problem such as diabetes or of a trauma to the eye.

A cataract rarely causes damage if it is left in the eye, except in cases in which there is blurred vision. There are very rare cases, however, of cataracts, when left in the eye long past the stage of blindness, causing inflammation and glaucoma. With the current methods of removal, surgery can be performed successfully at any stage of cataract development.

The only treatment for a cataract is the removal of the cloudy lens. There are various methods of surgically removing a cataract, and the specialist must decide which method is most suitable for each individual patient. For a description of the three main surgical procedures that are available for cataract extraction, and a list of the advantages and disadvantages of these techniques, please see the full article by Dr. Marvin Kwitko on our web site at

Dr. Marvin Kwitko performed his first lens implant operation at Bellechasse Hospital in Montreal in 1967. In 1968 he joined St. Mary's Hospital, and under the former chief, Dr. Gaston Duclos, continued this work there. Dr. Kwitko has trained more than 350 surgeons from Canada, the U.S. and abroad. He is currently the Chief of Opthalmology at St. Mary's Hospital in Montreal and an Associate Professor of Ophthalmology at McGill University.