Provocative tests and chronic simple glaucoma. I. Effect of atropine on the water-drinking test: intimations of central regulatory control. II. Fluorescein angiography provocative test: a new approach to separation of the normal from the pathological.

Provocative tests and chronic simple glaucoma I. Effect of atropine on the water-drinking test: inti- mations of central regulatory control II.Fluorescein angiography provocative test: a new approach to separation of the normal from the pathological GEORGE L. SPAETH AND NIBONDH VACHARAT Glaucoma Service, Wills Eye Hospital, Philadelphia To distinguish between the severely affected and the entirely normal presents little difficulty.However, when findings are at the outer limits of "normal", * or when the presence of one "abnormal" sign conflicts with other "normal" characteristics, then diagnosis becomes a subtle art necessitating a combination of knowledge, observation, imagination, and intuition.The aim of provocative tests is to establish the diagnosis before damage gives rise to manifest symptoms.For example, the diagnosis "glaucoma" may be made with relative certainty in patients stamped with the three hallmarks of the disease: intraocular pressure above 21 mm.Hg; glaucomatous cupping of the optic disc; and glaucomatous visual field loss.But where on the probability scale extending from normal to diseased is an individual to be placed who has only one of these findings, perhaps elevated intraocular pressure?To treat patients when they have no glaucomatous disease does them a great disservice, and a few may be significantly incapacitated thereby.To fail to treat those who have early glaucomatous disease will lead to loss of sight.The physician caring for the glaucoma suspect, or the "ocular hypertensive", is thus goaded by both horns of his dilemma.It is no wonder that so many attempts have been made to predict the future for this type of patient.A provocative test introduces stress upon the eye, the response of which is appropriately recorded.Experience has suggested that the intraocular pressure of the eye with glauco- matous disease, especially in an untreated state, usually reacts to stress in a more exagger- ated manner than does that of the normal eye.The understandable, but illogical, next step is to assume that an eye that reacts to stress in an exaggerated fashion has glaucomatous disease.Were this always true, it would be possible to diagnose glaucomatous disease reliably, even in the absence of evidence of optic disc cupping or visual field loss.*Normal has been used here as it is customarily employed.It is, however, an incorrect usage."Normal" correctly means the absence of pathology; it does not indicate an "average" condition, which is a statistically determined attribute unconcerned with pathology.For example, average weight in a large population of males is about I6o lb.Average weight for a group of entirely healthy 7' males, on the other hand, is about 230 lb.If a 5' i0o man weighed I6o lb., his weight would be both normal and average.If a 7' man weighed I6o lb., his weight would be abnormal but average.And if a 5' Io" individual weighed 230 lb.his weight would be neither normal nor average