• Glaucoma

    This prospective, observer-masked, cross-over study found a greater rise in IOP with the water drinking test than the caffeine test. Therefore, the caffeine test does not appear to provide an alternative in patients unable to tolerate the water drinking test.

    Subjects included 14 patients with open-angle glaucoma randomized to either the water drinking test or the caffeine test.  A masked examiner used Goldmann applanation tonometry to measure IOP in both eyes at baseline and every 15 minutes for one hour after the test. This was repeated the following week at the same time of day for the other test.

    The authors conclude that although the caffeine test is perhaps more tolerable than the water drinking test, this study has not shown the caffeine test to be an adequate alternative for assessing IOP peaks. They note that the caffeine test caused a minor increase in IOP, perhaps enough to discourage coffee consumption in the waiting room, but was inferior for assessing peak IOP.