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Assessment of established cases of chronic simple glaucoma.

1970; BMJ; Volume: 54; Issue: 4 Linguagem: Inglês

10.1136/bjo.54.4.217

1468-2079

R. F. Fisher, R. G. Carpenter, C. A. Wheeler,

Glaucoma and retinal disorders

Since tonography was first introduced by Grant (1950), patients with chronic simple glaucoma have repeatedly been shown to have a marked reduction in outflow facility (Kronfeld, I96I).Impaired outflow has also been correlated with changes in the struc- ture and patency of the trabecular meshwork (Teng, Paton, and Katzin, I 955; Yamashita, Becker, and Cibis, I960).This confirmed the view that impaired outflow facility, together with cupping of the disc and loss of the field, were constant characteristics of the glauco- matous eye (Becker and Shaffer, I96I).The present study was therefore uindertaken in proven cases of chronic simple glaucoma, as incdicated by cupping of the disc and loss of the field, firstly to discover if impaired outflow facility were a better measure of the degree of glaucoma than raised intraocular pressure and, secondly, to see if it were possible to predict the loss of field from the impaired outflow facility. Material and methodsIn the course of i8 months, 400 patients with proven open-angle chronic simple glaucoma presented for treatment and from these patients 33 (fifty eyes) were chosen for this survey.Two factors account for this low rate of selection: (I) Only patients who had received no previous treatment were included;(2) Of these patients only a few fulfilled the stringent criteria for field testing (Fisher, I968).To obtain a full range of cases a few apparently normal eyes of patients with undoubted chronic simple glaucoma in the other eye were included.All eyes were subjected to a general ophthalmological examination, which included gonioscopy. FIELD ESTIMATIONThe method of selection and examination of the visual fields has been described previously (Fisher, I968).In this study all quadrants of the field were examined separately in a Goldmann perimeter, with a target of 4 mm.2 and of brightness 45 apostilbs.This target was used since the diagnosis was not in question and only definite and permanent field defects were ascertained.Furthermore, a target of this size and luminosity gives an average field, extending about 450 in the nasal quadrant, and nose and brow obstruction is usually absent (Fisher, I967).The centripetal and centrifugal fields were repeated on two separate occasions, and if discrepancies greater than 50 per quadrant were found the patient was excluded from the study.