Peak Intraocular Pressure Time During Water-Drinking Test Associated With Glaucoma Severity

Optician with tonometer and patient at eye clinic
Optician with tonometer and patient at eye clinic
Clinicians may consider using the water-drinking test as an additional tool to evaluate patients with glaucoma, a study suggests.

The time of intraocular pressure (IOP) peak occurrence during the water-drinking test (WDT) appears to be associated with glaucoma severity among patients with primary open-angle glaucoma, according to a study published in the Journal of Ophthalmic and Vision Research.

“Eyes with more severe disease had a later IOP peak than eyes with less severe disease,” the researchers explain. The retrospective, cross-sectional study reviewed 98 eyes of 49 patients (age range, 33-95; 88% White; 54% women) with primary open-angle glaucoma. The researchers administered the WTD, which consisted of a baseline IOP measurement followed by participant ingestion of 800 mL of water within a 5 minute time frame. They repeated 3 successive IOP measurements at 15 minute intervals. The team assessed peak time of IOP occurrence and visual field mean deviation (MD) with 24-2 standard automated perimetry. 

Patients reported taking an average of 2 IOP lowering medications (range, 0–5). After adjusting for the number of medications, the investigators found that the MD value was significantly associated with the time of IOP peak occurrence (P =.020), but not with the IOP peak values (P =.238).

“Eyes with later IOP peaks experienced continued IOP rise during the WDT until the maximum IOP was reached (IOP peak) and as so, a longer period of IOP elevation than eyes with earlier IOP peaks, possibly reflecting a better ability of these eyes to handle transient IOP elevation,”  according to the investigators. “This study demonstrated that the time of occurrence of IOP peak measured with the WDT was associated with glaucoma severity and might be an additional tool to evaluate glaucomatous patients.”

Limitations of the study included the retrospective, single center design, small sample size, and lack of ethnic diversity among the cohort.


Susanna CN, Susanna BN, Susanna FN Jr, Susanna R, De Moraes CG. Peak intraocular pressure time during water drinking test and its relationship with glaucoma severity. J Ophthalmic Vis Res. 2022;17(1):27–32. doi:10.18502/jovr.v17i1.10167