Cataract Extraction With Alpha-Chymotrypsin a Controlled Trial

Abstract

Edgware, Chase Farm, and Bolingbroke Hospitals IT seemed necessary to verify, by a controlled trial, the reported action of alpha-chymotrypsin in loosening the suspensary ligament and facilitating the operation of intracapsular extraction. Many authors have praised the use of this enzyme and given clinical impressions of its value, but in none of these series have controls been used.Trial Procedure First fifty intracapsular extractions were performed in an uncontrolled series so that the operator should become thoroughly familiar with the technique.In order to make a true assessment fifty ampoules were prepared by the hospital pharmacist with their accompanying ampoule of diluent, and these were numbered 1 to 50. Some of the ampoules contained active A.C.T. and the others an inert substance. The numbered labels were so wrapped round that it was impossible to see into the ampoule and there was no way of knowing whether an active or inert substance was introduced into the eye. Case notes were made after each operation and the key was kept in a sealed envelope and not referred to until the end of the complete series.All cases were operated upon under general anaesthesia, and the section was a small von Graefe section enlarged with scissors without a conjunctival flap. One pre-placed groove suture and four post-placed sutures were inserted. After the introduction of the unknown solution and the recommended wait of 3 minutes, the iris was fully retracted under the raised cornea and the lens grasped tangentially at 12 o'clock as near as possible to the equator with Arruga's forceps under direct vision.

Multiple Methods Technique for Intra-Capsular Cataract Extraction

“…COGAN, Symons, and Gibbs (1959), Ainslie (1959), Townes (1960), Murray and Drance (1960), Moore (1961), Pahwa (1961), Barraquer (1961), and others have noticed that, after the use of alpha-chymotrypsin (Barraquer, 1958) in intra-capsular cataract extraction in patients above 25 years of age, although the lens was easily removed, there was an increased incidence of post-operative complications, including delayed healing of the wound, delayed formation of the anterior chamber, and greater liability to iris prolapse, secondary glaucoma, hyphaema, and striate keratitis. These complications are due to the effect of the enzyme on the corneal and sceral lips of the wound, on the cut ends of the blood vessels, and on the corneal endothelium.…”

The Lens and Vitreous

“…* There is, however, greater recognition of complications attending its use. 31,40,41,43,49,51 Retardation of wound healing has been noted and has stimulated the use of multiple sutures, posterior section in the vascular limbus, thorough irrigation of the anterior chamber after use of the drug, and instilla¬ tion of acetylcholine into the anterior cham¬ ber after cataract removal.30·31,40,49 Compli¬ cations previously attributed to it such as massive liberation of iris pigment, hyaloid rupture, secondary glaucoma, and retinal detachment were thought to result from faulty technique.40 «-Chymotrypsin is indi¬ cated in the 20 to> quent. This is attributed to a strong capsular-hyaloid attachment and the elasticity of the young sclera which encourages an anterior displacement of the vitreous.…”