Results for water-drinking test, before and after laser iridotomy, in primary angle-closure suspects

Significance: Intraocular pressure and ocular biometric changes were similar before and after laser iridotomy in response to the water-drinking test in a cohort of patients at risk of angle closure. The water-drinking test does not seem to be a good provocative test to determine which eyes would benefit from a laser iridotomy. Our data call into question the preoperative predictive value of this test. Purpose: The aim of this study was to evaluate the effect of water-drinking test on intraocular pressure and ocular biometric parameters, before and after laser peripheral iridotomy, in patients with an occludable angle. Methods: Twenty-seven patients, who met the inclusion criteria and had at least 180 degrees of iridotrabecular apposition, underwent a complete eye examination followed by the measurement of ocular biometric (using LenStar LS-900; Haag-Streit AG, Koeniz, Switzerland) and anterior chamber parameters (using Pentacam HR; Oculus Optikgerate GmbH, Wetzlar, Germany). All the measurements were repeated 30 minutes after the water-drinking test. Two weeks after laser peripheral iridotomy, all the measurements were repeated both before and after the water-drinking test. Results: The mean ± SD of the age of the participants was 57 ± 9 years, and 23 (85.2%) were male. Intraocular pressure increased after the water-drinking test in both pre-laser peripheral iridotomy (17.0 vs. 19.3 mmHg, P <.001) and post-laser peripheral iridotomy (15.6 vs. 18.6 mmHg, P <.001) conditions. The thickness values of central cornea increased slightly after the water-drinking test in pre-laser peripheral iridotomy (535 vs. 538 μm, P =.001) compared with post-laser peripheral iridotomy (532 vs. 536 μm, P =.003). The water-drinking test had no significant effect on other biometric or anterior chamber parameters, before or after laser peripheral iridotomy. Conclusions: The water-drinking test increased intraocular pressure, both before and after laser peripheral iridotomy. Laser peripheral iridotomy had no significant effect on the amount of intraocular pressure change after the water-drinking test. The water-drinking test has no effect on other biometric or anterior chamber parameters.