Success Of Implant Surgery

Press, Volume XCIX, Issue 29401, 31 December 1960, Page 4

Success Of Implant Surgery

The artificial lens, inserted into the eye of a patient after the removal of a cataract (a condition in which the eye’s natural lens goes opaque), is a new and remarkably successful treatment developed over the last decade. Mr Peter Choyce has refined the plastic lens design and the method of its insertion to a point where full vision is being restored to three-quarters of his patients and improved in almost every case. Previously, patients have been without the use of an eye through injury or disease, perhaps for many years. Cataract in one eye is quite common. Among children it is often caused by the impact of a ball, thorns, airgun pellets, or hard blows to the eye.

There was the typical case of Michael, aged six, whose left eye was punctured by a thorn. The ensuing cataract was removed but he could not manage to wear a contact lens for a useful period. In an article in the “New Scientist” last November, Mr Choyce said of Michael’s case: “A correcting anterior chamber implant was inserted, and the good eye occluded to overcome the laziness of the injured eye. Three months later the vision of the injured eye was back to normal without' any special treatment. Two years later he still has normal vision, normal binocular function and leads the normal life of a boy except that he is not allowed to box or play Rugby football.”

"The danger with children,” explains Mr Choyce, “is that if they are not. treated soon after a cataract operation, the injured eye becomes lazy.” Without the implant, Michael’s left eye would have been permanently lazy and he would have had an ugly squint. Occasionally implants are inserted in both eyes, as in the case of cataracts which are the result of a mother having German measles during pregnancy. This sometimes leads to cataracts in both of the baby’s eyes. 300 Patients Mr Choyce, who is 41, has been consultant at Southend General Hospital since 1954. He has been working with implants for three years, treating more than 300 patients with them. He now does about’ two implant operations a week. As a result of his original research in surgery, Mr Choyce is a Hunterian Professor of the Royal College of Surgeons, and in that office he will lecture at the college next April. He has already published papers in professional journals in Britain and

the United States and lectured in America and Australia.

Some ophthalmologists have been cautious about these developments and no-one knows what will happen to eyes containing implants say 40 or 50 years hence. However, the evidence so far is that there is no reaction in the eye at all and the satisfaction given to patients and surgeons is immense.

The London makers of the implants, Rayners, Ltd., report that they have supplied sets of these implants to about 300 doctors throughout the world, including more than 100 in Britain. Some have done a few trial cases for cautious observation; others have ordered many sets. (Rayners mould six implants for each patient—duplicates of three different lengths of implant to ensure exact fit and as an insurance against an accident with one of the carefully sterilised fragments of perspex.) There is at least one doctor in Australia who has started inserting implants. He was a house surgeon with Mr Choyce at Moorfields, London’s famous eye hospital, where Mr Choyce was resident and repaired hundreds of eye injuries. , "I would like to see some surgeons take it up in New Zealand,” says Mr Choyce. “Say, one in Auckland, one in Wellington, and one in the South Island to whom patients could be sent.” War-time Discovery There has been a good deal of research into finding a material with optical properties and safe to insert into the human eye. During World War II a London eye surgeon, Mr Harold Ridley, found that fragments of aircraft canopy perspex which had entered the eyes of pilots did not necessarily produce any reaction. From this discovery, Mr Ridley developed the idea of replacing the natural lens, removed because of cataract, with a perspex one. He began work 10 years ago and had many successes.

Mr Ridley put the lens behind the iris, the coloured part of the eye that functions like a camera diaphragm over the lens. An Italian surgeon, Dr. Benedetto Strampelli, modified the method by inserting the lens in front of the iris, at which point it becomes not a lens but an implant, the central part of which acts as a lens.

Mr Choyce’s particular contribution has been to design implants which are thinner and shaped so as not to irritate and damage the sensitive cornea. Although the skilful dispensing of spectacles and contact lenses corrects many sight defects there

are many people, especially children and elderly people, who have developed cataract or had the lens of one eye damaged by accident or disease and for whom these answers were not suitable.

Ordinary spectacle lenses fail to correct the vision in these cases: the difference between the image sizes received in each eye is so great, about 30 per cent., that fusion of the two into one impression is impossible. The same, though much lesser, difficulty occurs with contact lenses. With these, the difference in image size is reduced to about 10 per cent. The lens of an implant, so close to the proper lens position, eliminates this problem for the patient’s sight mechanism. According to Mr Choyce, it is found that in many cases patients discontinue wearing their contact lenses after a few years. Furthermore, contact lenses cannot be fitted to children under the age of seven or eight. Nor are many elderly patients interested in being fitted with them. So there is a big number of cases which can only be treated with implants. Mr Choyce has had a remarkable proportion of successes with implants. Full vision with both eyes had been restored to 75 per cent of his patients. As many as 90 per cent, have been able to see as much as had been expected; and where the results were disappointing the patients were at least no worse off than before. Since the early operations the proportion of successes has constantly improved. “With experience, this is not a difficult operation,” says Mr Choyce. “It is much easier than a corneal graft for example. I make it easy for myself by taking care to prepare the patient properly. In the first place the patient must be carefully chosen, and then prepared by a preliminary operation. “I am satisfied that the technique is of very great importance.”