Surgical Prognosis in Glaucoma Simplex

Abstract

Though it has long been recognised that glaucoma is not cured by operations which control the intraocular pressure, comparatively few authors have attempted to analyse their material in a systematic manner. Reese in 1939 showed that 10 to 40 O/O of his cases made normotensive by surgery lost vision subsequently, and Burke in 1940 gave a proportion of 50 o/o for corresponding cases watched over a 5 year period. The latter author related prognosis to the severity of the visual defect at operation rather than to the age of the patient.It was not until 1943 that Sidney A. Fox proposed certain criteria upon which future surveys should be based so that results could be strictly comparable with those of other surveys, and readily appreciated. The thesis set out by Kronfeld and McGarry (1948) was one of the first to adopt this system, and as a model investigation will be referred to in later parts of this thesis. These authors found a visual failure rate, in glaucoma simplex eyes made normotensive by surgery, which varied from 12 to 50 O/O according to the degree of failure already present at operation; the course to be taken was usually determined by the end of the first year's follow-up. With narrow-angle cases, however, a constant failure rate of only 10 O/O was obtained irrespective of initial severity. Reese (1939) had obtained similar, if not strictly comparable figures for chronic glaucoma (10-40 O/O failures). Subsequently, we have the papers written by Briantseva (quoted by Samoiloff A. J., 1948), Duke-Elder (1949), Sourdille (1950), and Lloyd (1951 a). Most of the authors illustrate the rather unsatisfactory results of surgery which has succeeded in lowering the tension. Duke-Elder gives an average failure rate of 300/0 (15 to 500/0), griantseva 48 to 89 O/O. The results of Sourdille are rather more favourable, with an average failure rate of 15 O/O. The authors quoted above cannot always be said to have acknowledged or compensated for all types of selectivity in the cases composing their series; nor hqve they applied statistical methods to *)