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 (IOPΔ) 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±4.0 mm Hg, 18.7±2.8 mm Hg, 18.6±2.5mm Hg; P<0.001), IOPmean (22.6±3.3mm Hg, 17.2±2.6 mm Hg, 17.2±2.4 mm Hg; P<0.001), IOPΔ (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.