Intraocular Pressure Characteristics of Exfoliative Glaucoma and Exfoliation Syndrome as Determined With the Water Drinking Test

Purpose: To investigate the intraocular pressure (IOP) characteristics of patients with exfoliation glaucoma (XFG) and exfoliation syndrome (XFS) during the water drinking test (WDT). Methods: This was a prospective observational study undertaken at an academic setting. Consecutive patients with XFG whose office IOP levels were < 21 mm Hg, normotensive XFS patients, and control subjects underwent WDT, which involved ingestion of 1 L of water within 5 minutes. The IOP was measured before and 4 times after water ingestion at 15-minute intervals. Maximum IOP (IOPmax), mean IOP (IOPmean), IOP increase (IOP Delta) from baseline IOP to IOPmax, and percentage of IOP fluctuation (IOPfluct) during the WDT were compared across groups. One-way analysis of variance (ANOVA) test or the Kruskal-Wallis test was used for comparisons. Results: The age, gender ratios, visual acuity level, central corneal thickness, and office IOP levels were similar between the 3 groups. As compared with patients with XFS and controls, XFG patients revealed significantly higher values for all IOP measurements at 15 minutes intervals as well as IOPmax (25.1 +/- 4.0mm Hg, 18.7 +/- 2.8 mm Hg, 18.6 +/- 2.5 mm Hg; P < 0.001), IOPmean (22.6 +/- 3.3 mm Hg, 17.2 +/- 2.6 mm Hg, 17.2 +/- 2.4 mm Hg; P < 0.001), IOP Delta (9.2 +/- 3.4 mm Hg, 4.4 +/- 2.1 mm Hg, 3.7 +/- 1.5 mm Hg; P < 0.001), and IOPfluct (60.1 +/- 24.0%, 33.4 +/- 20.0%, 25.7 +/- 11.3%; P < 0.001). Conclusions: Medically treated XFG patients, but not XFS subjects, reveal significant IOP elevations during WDT indicative of impaired trabecular outflow facility.