Cataract extraction, usually accompanied by lens replacement, is both the most common and the most successful operation performed in the United States today. The development of cataracts, a clouding of the lens of the eye, is the most common cause of blindness in the world, particularly among the elderly.
The most common modern technique of lens extraction, known as Kelman phacoemulsification (KPE), has a success rate that is quickly approaching 99%, and has a very low incidence of complication. The surgery is usually brief and painless, requiring only local anesthesia and no hospital stay. It has restored sight to well over a million people since it was first introduced in 1967.
KPE was first introduced by Dr. Charles D. Kelman, perhaps the single most prominent ophthalmologist of the twentieth century. Dr. Kelman had already pioneered earlier technology for lens extraction, most notably a freezing instrument called the cryo-probe. The surgery which Kelman and his colleagues were using prior to 1967 involved extracting the cataract intact from the eye, and required a large incision (often as much as 150 degrees, nearly half the circumference of the cornea). The operation often resulted in damage to the gel of the eye, known as the vitreous, which often resulted in vision distortion when the vitreous re-congealed. Complications were frequent, and patients recovered slowly, often enduring a week-long hospital stay and extended bedrest. It was often necessary to place sandbags around the patient’s head to prevent him or her from moving while the eye healed. Since there were as yet no techniques for lens replacement, patients had to rely on so-called “coke bottle glasses” after the operation. Even in the best of cases, these glasses left gaps in the patient’s vision. The procedure was preferable to the alternative, which was total blindness, but the technology clearly left much to be desired.
After much arduous trial and error, working on a $280,000 research grant, Dr. Kelman finally arrived at the procedure of phacoemulsification in 1967. The procedure employs a vibrating ultrasonic tip which uses an ultrasound radio wave to break up the clouded lens, then uses a small needle to suction the tissue from the eye. The technique requires a mere 3 mm incision, and can often be performed without breaking blood vessels, which makes the operation a possibility for people on blood-thinning medication. In 1975, Dr. Kelman began designing lens implants for use in conjunction with the cataract extraction procedure he had already devised.
In a recent presentation to the XIX congress of the European Society of Cataract and Refractive Surgeons (ESCRS) in Amsterdam, Dr. K. said, "Although I invented phacoemulsification, I cannot tell you that I sat down one night, closed my eyes and envisioned this beautiful operation that you see today. It was very far from that." Dr. Kelman began by trying to dissolve the membrane by means of injecting an enzyme into the eye, and then turning the patient over onto his stomach and vibrating his head until the fragmented lens fell into the anterior chamber. He attempted to catch the lens by means of a folded rubber pocket inserted in the eye. "Obviously it was a very unsophisticated and unworkable solution," Dr. Kelman commented to the ESCRS. He was experimenting primarily with cadavers, and he was never able to bring the lens into the anterior chamber, let alone successfully retrieve it. His next solutions involved tools based on meat grinders, miniature rotating needles, and electric toothbrushes, none of which were successful.
The story of Dr. Kelman’s Eureka! moment is a legend in his field. He was having his teeth cleaned at his dentist’s office when he asked his dentist about the ultrasonic device being used to clean his teeth. He instantly realized that this rapidly vibrating ultrasonic tip was exactly the kind of tool required for the successful implementation of this new technology. "People may think, "Oh Kelman, you were sitting at the dentist one day and the dentist used this ultrasonic drill and voila, phacoemulsification. I could have done that!" But the point is that you have to go through the failures in order to recognize something that has the possibility of working."
Dr. Kelman was named "Ophthalmologist of the Century" by the International Congress on Cataract and Refractive Surgery. In addition to numerous other awards in his field, he also received the "Inventor of the Year Award" from The New York Patent, Trademark and Copyright Law Association for his development of phacoemulsification. In June of 1992, Dr. Kelman was awarded the Prestigious National Medal of Technology by President Bush.
The impact of this procedure has been enormous, and its future potential may be even farther-reaching. Neurosurgeons have also adopted the Dr. Kelman’s phacoemulsification device as a means to dissect tumors found in the brain and spinal cord tissue of young children. The technology has not only saved millions of people from blindness; it has also saved hundreds of lives. Cataract extraction currently accounts for Medicare’s single largest expenditure because it is so often necessary and possible for people over 65, over twenty-five percent of whom suffer from cataracts. (Among people over 80, the percentage is fifty percent). The number of people suffering from cataracts worldwide is now at 17 million, with 28,000 more patients being identified every day, and the World Health Organization (WHO) has made targeting cataract blindness one of its major health goals for the next twenty years. Dr. Kelman has already made a proposal to the WHO suggesting possible means of bringing cataract surgery to the developing world, and many of his colleagues are devoted to the same problem. It seems likely that the importance of this surgery will only increase as more and more people are reached by this technology.