Comparison of Water Drinking Tests Performed with 1000 and 650 ml of Water

Abstract

 

Purpose:

 

To compare the intraocular pressure (IOP) profiles and discomfortduring the water drinking test (WDT) performed with 1000mL and650ml of water.

 

Methods:

 

This prospective and observational study included 25 patients(mean age 67.1 years, 64% female) with primary open-angle glaucomaunder treatment. All patients underwent the WDT twice, firstwith 650ml and two weeks later with 1000ml, always at 10am.IOP was measured at baseline and patients were then instructedto drink the water in 10 minutes. IOP measurements were obtainedthree times, at 15-minute intervals. At the end of the study,each patient rated the discomfort related to water intake ona scale (0 to 10). Peak IOP agreement was analyzed with Bland-Altmanplot, and discomfort scores were compared using Wilcoxon SignedRanks test.

 

Results:

 

Peak IOP with 1000ml occurred at 15 min. for 72% patients andwith 650ml at 30 min for 56% patients. Bland-Altman plot revealeda fixed bias of 0.6 for higher peak IOP in 1000ml test (95%limits of agreement -4.7 to 6.0). 56% patients had a differencein peak IOP on both tests smaller than 2mmHg. Discomfort scoreswere smaller in 650ml test (0.68 vs 3.52, P<0.001).

 

Conclusions:

 

WDT with 1000ml and 650ml have moderate agreement in peak IOP.Patients found 650ml WDT more comfortable.  

 

 

Keywords: intraocular pressure • stress response