Effect of Switching From Latanoprost to Bimatoprost in Primary Open-Angle Glaucoma Patients Who Experienced Intraocular Pressure Elevation During Treatment

Purpose: We investigated the intraocular pressure (IOP) variations after switching from 0.005% latanoprost to 0.01% bimatoprost in open-angle glaucoma patients who experienced IOP elevation during treatment. Patients and Methods: Retrospective, interventional cohort study. Of the 625 patients with open-angle glaucoma, we included 41 patients on latanoprost who showed a peak IOP increase of at least 15% [assessed during the water drinking test (WDT)2] relative to the peak IOP measured during the previous WDT (WDT1). Main Outcome Measure: Baseline, peak, and IOP measurements at each timepoint (15, 30, and 45 min) during all 3 WDT sessions (WDT1, WDT2, and WDT3) were measured. Results: The mean peak IOP was 15.6 mm Hg (SE, 0.73) during WDT1; 21.1 mm Hg (SE, 0.73) during WDT2; and 16.1 mm Hg (SE, 0.73) during WDT3 (P < 0.001, repeated-measures analysis of variance). Comparing WDT1 versus WDT2, the mean peak IOP difference was 5.5 mm Hg (P < 0.001); for WDT1 versus WDT3, the difference was 0.5 mm Hg (P = 0.312); for WDT2 versus WDT3, the mean difference was -5.0 mm Hg (P < 0.001). The mean IOP at each timepoint during the WDT sessions was significantly different between WDT1 and WDT2 and between WDT2 and WDT3. Conclusions: Our study suggests that glaucoma patients on latanoprost who experienced IOP elevation during the course of therapy may benefit from switching to bimatoprost. This alternative can potentially postpone more costly or invasive treatment options.