A comparison of water drinking test among normotensive and ocular hypertensive eyes with pseudoexfoliation

In pseudoexfoliation, the Water Drinking Test (WDT) can unmask Intraocular pressure (IOP) behaviour not evident at baseline. Normotensive and ocular hypertensive pseudoexfoliation eyes need to be segregated based on their risk profile.

Pseudoexfoliation is associated with elevated and fluctuating IOP and a heightened risk of glaucoma. While WDT is used to reveal peak IOP and fluctuation, comparative data between normotensive and ocular hypertensive PEX eyes are limited. WDT responses were compared across these subgroups to identify high-risk phenotypes.

In this cross-sectional observational study, 137 treatment-naïve pseudoexfoliation eyes without glaucomatous optic neuropathy underwent WDT (1 L water over 10 min). IOP was measured at baseline, 15, 30, 45, and 60 min. Eyes were classified as normotensive (≤21 mmHg; n = 95) or hypertensive (>21 to < 30 mmHg; n = 42). Derived metrics included IOPΔ, IOPnet, IOPrange, and IOPfluct; WDT positivity was predefined (Δ≥8 mmHg or ≥30%). Group comparisons used t-tests/χ² as appropriate.

Both groups showed significant post-WDT IOP elevation. Hypertensive eyes had higher IOP at every time point (all p < 0.001) and more frequently reached IOPmax ≥30 mmHg (48% vs 11%, p < 0.001). Normotensive eyes more often exhibited IOPnet > 2 mmHg at 60 min (64% vs 40%, p = 0.04). WDT positivity was comparable (25% vs 36%, p = 0.30). Derived fluctuation metrics (IOPΔ, IOPnet, IOPrange, IOPfluct) were not statistically different between groups (all p > 0.05).

Despite similar fluctuation amplitudes, normotensive PEX eyes demonstrate delayed recovery (greater IOPnet), whereas hypertensive PEX eyes are prone to extreme peaks (IOPmax ≥30 mmHg). WDT provides complementary risk stratification in PEX, supporting tailored follow-up and earlier intervention in eyes exhibiting high-risk response patterns.