Role of the water-drinking test in medically treated primary open angle glaucoma patients

Purpose. - The water-drinking test (WDT) has recently re-emerged as a possible way to determine the competency of the trabecular meshwork. We performed a prospective interventional study to test the hypothesis that the WDT could be useful in assessing fluctuations in patients undergoing treatment for primary open angle glaucoma (POAG). Methods. - We included 122 patients; 62 on medical treatment for POAG (n = 123 eyes) and 60 controls (n = 120 eyes). The study group had been on intraocular pressures (10P) lowering treatment continuously for at least 3 months with stable 10P. The WDT was performed during fasting and was considered positive if it fluctuated > 6 mmHg. Results. - The patients on medical treatment had a mean age of 50.56 +/- 18.45 years vs. 51.35 +/- 11.22 for the controls (P=0.34); with 71% being female in the study group and 77% in the control group. In the study group; 52% were on beta blockers (n = 64), 27% combination of two or more medications (n = 33), 19% prostaglandin analogues (n = 24) and 2% alpha agonists (n= 2). The WDT was positive in 17.07% (n = 21) in the study group and 2.5% (n = 3) in the control group (P=0.0001). The mean fluctuation was 7.14 +/- 2.15 mmHg in the study group and 6.00 +/- 0 mmHg in the controls (P=0.33). A positive WDT was found in 33.33% (n=11) of those on combination therapy; 12.5% (n=3) prostaglandin analogues and 10.94% (n=7) beta Mockers (P=0.03). Combination therapy had the highest positive WDT fluctuation (7.54 +/- 2.87) followed by prostaglandin analogues (7.00 +/- 1.00) and beta blockers (6.57 +/- 0.78) with a P value of 0.44. Conclusions. - The WDT can identify significant fluctuations in eyes with POAG that are medically treated. (C) 2018 Elsevier Masson SAS. All rights reserved.