Intraocular Pressure and Corneal Biomechanical Changes after Water‑Drinking Test in Glaucoma Patients

Purpose: To evaluate intraocular pressure (IOP) and corneal biomechanical changes after water‑drinking test (WDT) in glaucomatous and normal eyes using Ocular Response Analyzer (ORA). Methods: This prospective study included 30 medically controlled, 30 surgically treated glaucoma patients and 30 normal individuals. Baseline measurements included central corneal thickness (CCT), ORA‑derived corneal hysteresis (CH), corneal resistance factor (CRF), corneal‑compensated IOP (IOPcc), and Goldmann‑correlated IOP (IOPg). Measurements were repeated 15, 30, and 60 min after drinking 1000 mL of water. Changes in ORA parameters were compared among the groups. Results: All groups showed a significant increase in IOPg and IOPcc at all test points. Peak IOP occurred at 15 min and decreased gradually over time but did not reach the baseline values at 60 min. The surgery group had significantly lower baseline IOPg and IOPcc (10.7 ± 3.1 and 12.8 ± 3.7 mmHg, P = 0.001 and 0.01), lower peak IOPg and IOPcc (14.4 ± 4.6 and 16.2 ± 4.6 mmHg, P = 0.003 and 0.034), and lower percent IOPg and IOPcc fluctuations (13 ± 5.6 and 15 ± 5.9, P = 0.0001 and 0.002), respectively, compared to the medical group. Baseline CH and its fluctuations were not significantly different among the groups. CH decreased to a trough corresponding to peak IOPcc. There was a significant negative correlation between IOPcc and CH (r = −0.609, P < 0.001). The medical group showed more CRF fluctuations compared to normal group.(P = 0.039). Conclusion: Surgically treated glaucomatous eyes show less IOP fluctuations and lower peak IOP after WDT compared to medically controlled and normal eyes.