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The Dark-Room Test

1954; BMJ; Volume: 38; Issue: 4 Linguagem: Inglês

10.1136/bjo.38.4.242

1468-2079

A. C. Higgitt,

Sir Stewart Duke-Elder ONE of the provocative tests used to reveal the instability of ocular tension characteristic of glaucoma is the dark-room test.It has been known for over 40 years that darkness can increase the intra-ocular pressure, slightly in normal eyes and markedly in some cases of glaucoma, but there is still lack of agreement about how this occurs.This is not surprising in that it reflects our ignorance of many of the fundamental processes of glaucoma.Gronholm (1910), who first described a case that showed this reaction considered that the pupillary dilatation reduced the drainage capacity of the iris, and Seidel (1922) attributed the change to obstruction ofthe angle of the anterior chamber by the periphery of the iris.Other authors deny the effect of angle block and implicate a neuro-vascular disturbance, which may be within the eye (Feigenbaum, 1931) or of a more widespread character, possibly involving the hypothalamic region (Magitot, 1948; Weinstein, 1953).Primary glaucoma may be divided into two.main groups, simple and con- gestive, the clinical features of which are well known.Anatomnical differences between these groups were first noticed by Priestley Smith (1887), who found the shallow anterior chamber to be a typical sign of the acute congestive form.Numerous observers, starting with Barkan (1936), found that eyes subject to attacks of acute glaucoma always had narrow chamber angles.Eyes of patients with chronic simple glaucoma may have angles of any width and in this respect do not differ from non-glaucomatous eyes of similar age group.Sugar (1941), investigating the mydriatic test, found that a marked rise of tension occurred only in eyes that had a narrow angle and that the angle was closed by the mydriasis.Kronfeld (1949) stated that the dark-room test is applicable only to such eyes, but no series of cases has been reported to con- firm this.Bloomfield and Kellerman (1947), comparing several provocative tests in eyes with chronic simple glaucoma, found the dark-room test to be of little value.This paper presents information obtained from about 400 dark-room tests, which were performed as part of the routine investigation of patients atten- ding the glaucoma clinic of the Institute of Ophthalmology.The problem was two-fold: to find out in what type of glaucoma (if any) the test would be of clinical value; and to study the mechanism of the rise of ocular tension.Method All tensions were recorded with the same Schiotz X tonometer and by the same observer,