The water-drinking test is presently employed to aid in diagnosing glaucoma in suspicious or borderline cases. 1 Rarely necessary in patients with intraocular pressures below 15 mm Hg or above 30 mm Hg, the test is primarily indicated in the group with values of 20 to 25 mm Hg. However, few comparisons of normal subjects and glaucoma suspects with intraocular pressures (IOP) in this range have been carried out. Most studies have used normal eyes with average intraocular pressures on the one hand, and patients with unequivocal glaucoma and elevated intraocular pressures on the other. 2-4 It would also be desirable to compare the effects of water drinking in suspicious and normal groups with comparable outflow facilities to evaluate whether this function is as significant as the level of intraocular pressure in determining the result of the test. It has been reasonably well demonstrated that the initiating sequence of events