Comparison of Intraocular Pressure Changes During the Water Drinking Test Between Different Fluid Volumes in Patients...

The main objective of this study was to compare the intraocular pressure (IOP) response during the water drinking test (WDT) performed with 800 mL, 1000 mL, and 10 mL/kg of body weight and to test its relationship with body mass index (BMI).

In this prospective, observer-masked, observational study, patients treated with primary open-angle glaucoma were evaluated. In group I, 29 consecutive patients with body weight ≤60 kg underwent an 800 mL fluid challenge followed by a second WDT session with 10 mL/kg of body weight no longer than 4 months apart. Group II included 30 consecutive patients with body weight >60 kg who underwent a 1000 mL fluid challenge followed by an 800 mL test no longer than 4 months apart. IOP was measured before (baseline) and after water ingestion every 15 minutes for 45 minutes.

In group I, there was no significant difference in baseline or peak IOP between 800 mL and 10 mL/kg of body weight tests (P=0.12 and 0.56, respectively). However, 10 mL/kg tended to lead to consistently lower IOP values and a biased response in eyes with higher IOP. In group II, there was also no significant difference in baseline or peak IOP between 800 and 1000 mL tests (P=0.26 and 0.72, respectively). No biased response was observed in this group. There was no significant association between IOP peak and BMI with 800 mL (P=0.18), 10 mL/kg (P=0.29), or 1000 mL (P=0.34).

There was overall good agreement between WDT results with different fluid volumes. The response to the volume loads tested in this study was not influenced by the BMI.