Clinical Report: Stress Testing Exposes Glaucoma Risk

Overview

In a prospective study of 67 glaucoma eyes, higher peak intraocular pressure (IOP) during a water-drinking test (WDT) was associated with faster visual-field loss and retinal nerve fiber layer (RNFL) thinning. Among eyes with office IOP at or below severity-specific targets, 37% exceeded 21 mmHg during the WDT; the study authors describe the test as exploratory and call for confirmation in larger populations.

Background

Office IOP measurements may not capture pressure peaks that occur outside routine clinical measurement. The WDT is a standardized physiological challenge in which participants drink water and IOP is measured over the following 45 minutes. The study assessed whether WDT responses were associated with subsequent functional and structural glaucoma progression. Current AAO guidance identifies higher peak IOP during follow-up as associated with greater progression, while noting that evidence on diurnal IOP fluctuation is inconsistent and requires further study.

Data Highlights

Key Findings

• Participants drank one liter of water within five minutes; IOP was measured before ingestion and at 15, 30, and 45 minutes.
• Investigators recorded peak IOP, rise from baseline, and within-session fluctuation, and tracked visual-field mean deviation and RNFL thickness longitudinally.
• Eyes with WDT peak IOP above 21 mmHg had significantly faster mean-deviation loss and faster RNFL thinning than eyes at or below that threshold.
• Of 59 eyes with acceptable office IOP based on severity-specific targets, 22 (37%) exceeded 21 mmHg during WDT and subsequently showed faster functional and structural deterioration than apparently controlled eyes below the threshold.
• Among 13 eyes meeting the study criteria for rapid functional or structural progression, 10 reached a WDT peak above 21 mmHg, whereas routine office measurements classified 3 as above target.
• The study was exploratory: the cohort was modest, mean follow-up was just over two years, treatment changes were not controlled, and the authors stated that larger multicenter studies are needed.

Clinical Implications

The study authors propose that WDT may serve as a composite stress test of ocular IOP homeostasis and may reveal pressure responses not apparent from resting office measurements. The AAO Preferred Practice Pattern states that testing frequency may need to increase with greater disease severity, suspected faster progression, or failure to meet target IOP; the study does not establish WDT-guided management or treatment escalation.

Conclusion

In this cohort, elevated WDT peak IOP was associated with faster functional and structural glaucoma progression, including among eyes with acceptable office IOP. The findings require confirmation in larger multicenter populations before the test's role in clinical management can be established.

Related Resources & Content

1. American Academy of Ophthalmology, Ophthalmology, 2026 -- Primary Open-Angle Glaucoma Preferred Practice Pattern®
2. Heijl et al., Archives of Ophthalmology, 2002 -- Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial
3. Glaucoma Physician, 2024 -- Chronic Stress Linked to Glaucoma Risk, NIH Study Finds
4. Optometric Management, 2023 -- CLINICAL Glaucoma
5. Optometric Management, 2023 -- CLINICAL: Glaucoma
6. Authors not specified, Eye, 2024 -- Comparison of intraocular pressure profiles during the water drinking test and the modified diurnal tension curve
7. optometric management — CLINICAL Glaucoma
8. Primary Open-Angle Glaucoma Preferred Practice Pattern®
9. Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial
10. Comparison of intraocular pressure profiles during the water drinking test and the modified diurnal tension curve