The water test has remained a valuable and simple provocative measure in establishing a diagnosis of chronic simple glaucoma. The most disturbing feature has been the low percentage of positive results obtained in cases of established glaucoma. The proportion of positive results increases with the severity of the glaucomatous process and has been related to the height of the intraocular pressure prior to the start of the test. When the intraocular pressure is continually elevated, the water test loses its diagnostic significance. The percentage of positive results reported in diseased eyes varied from 32.9% reported by Leydhecker1 and 45% reported by Kronfeld.2 Drance3 reported that approximately 1 in 3 of all the patients undergoing a water provocative study had an inadequate hemodilution, and a positive test could therefore not be expected. Negative tests in those cases have no bearing on the evaluation of the glaucomatous process. More