Abstract
Purpose :
To determine whether a 800-mL fluid challenge produces similar intraocular pressure (IOP) peak response compared with the traditional 1000-mL water drinking test (WDT), in order to verify if these two volumes of water intake are interchangeable.
Methods :
Prospective, observer-masked, observational study. Treated patients with primary open angle glaucoma were recruited from a private specialist glaucoma practice. One eye of each patient was included. In the first WDT, subjects underwent a 800-mL fluid challenge. A second WDT with the alternate volume of water (1000 ml) was performed within the period of no longer than four months. Intraocular pressure (IOP) was measured with a calibrated Goldmann applanation tonometer before (baseline) and after water ingestion every 15 min for 45 minutes. Primary statistical analysis was performed using a linear mixed effects models with random intercepts. Agreement between tests was analyzed with Bland-Altman plots.
Results :
Thirty patients were included in this study. The mean patient age (±SD) was 70.7 (±10.8) years, and 15 (50%) patients were female. There was no significant difference in baseline IOP between the 800-mL and 1000-mL WDTs (P = 0.26). Both fluid challenge volumes produced a statistically significant rise in IOP from baseline at 15, 30 and 45 min after water ingestion (all P<0.001). The mean ± SD peak IOP was15.6 ± 3.4 mmHg in the 800-mL and 15.6 ± 3.42with 1000-mL. The difference in IOP peaks was not statistically significant (d =-0.06 mmHg; 95% CI=-0.83 to 0.71; P=0.86). Mixed effects models revealed no significant different at any given time-point (all P>0.53).
Conclusions :
Differences in the results of the WDT using 800 and 1000 mL are not statistically different. Moreover, 800 mL may be more comfortable to patients as the results of the WDT using these two volumes of water may be interchangeable.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.