A Recent Development in the Surgery of Cataract By

EXTRACTION of the human lens for cataract has been performed with various improvements and increasing success for just 200 years. Daviel (1748) reported the first planned extraction but, as is frequently the experience of pioneers, his operation did not at first prove popular and most surgeons continued to couch cataracts, dislocating the opaque lens within the eye as had been practised in various countries with some measure of success since 1000 B.C. The discovery of cocaine as a local anaesthetic in 1884 rendered intra-ocular operations on elderly people less hazardous as well as painless, and from that time cataract ceased to lead almost inevitably to blindness. The extracapsular extraction which left in place the posterior lens capsule seemed for many years the only practicable operation and to this day, with its many improvements in technique, still has an honoured place in surgery. At first the surgeon would not operate until the cataract was mature, when it could be completely expressed, but this entailed the patient waiting perhaps years in almost complete blindness until courage was found to operate. L'ater, with improvements in asepsis, it was found that if any soft cortex remained after expression of the nucleus it could safely be removed by irrigation with normal saline. Earlier operation could therefore be undertaken without great risk of post-operative iridocyclitis and with a reasonable chance of a clear pupil. Later still, anterior capsulectomy further improved technique and diminished the need for capsulotomy of " after cataract "; for the posterior capsule is extremely thin and, in the absence of the anterior capsule and remaining lens cortex, seldom requires division. The modern extracapsular extraction gives very good results, and the intact posterior capsule is a useful bulkhead in the eye, preventing forward bulging or prolapse of the vitreous and reducing the risk of detachment of the retina. Early in the 20th century intracapsular extraction was introduced by Smith, Elschnig, and others, but for many years this operation, which permits removal of very immature cataracts, was regarded by many as unjustifiably dangerous, and it is only recently that it has become more popular than the well-tried and generally satisfactory extracapsular extraction. This procedure, though accompanied by considerably increased risk in the hands of inexperienced operators, is, within its limitations, practically the ideal, and