DESIGN: This was a prospective, randomized, observer-masked, crossover parallel comparison trial.

METHODS: Forty-one patients with primary open-angle glaucoma or ocular hypertension on nonfixed combination of latanoprost and timolol with IOP of 21 mm Hg or less were randomized to either bimatoprost-timolol or travoprost-timolol fixed combinations for 8-week treatment period. Intraocular pressure was measured at 8 AM, 12 PM, 4 PM, and 8 PM at the baseline and at the end point. Conjunctiva hyperemia and superficial punctate keratopathy after treatment with each fixed combination therapy were assessed and compared with the baseline. Patients were then switched to the opposite drug without a medication-free period for another 8-week, and diurnal IOP measurement was repeated.

RESULTS: Bimatoprost-timolol fixed combination reduced the baseline mean diurnal IOP statistically significantly from 17.3 mm Hg [95% confidence interval (CI), 16.8-17.7 mm Hg] to 16.4 mm Hg (95% CI, 15.9-17.0 mm Hg) (P = 0.036). Travoprost-timolol fixed combination lowered the mean diurnal IOP to 17.1 mm Hg (95% CI, 16.5-17.7 mm Hg), but it was not significant. Direct comparison between the 2 fixed combinations showed no significant difference. Both fixed combinations had no significant effect on conjunctiva hyperemia. Interestingly, patients on travoprost-timolol fixed combination had significantly less superficial punctuate keratopathy (P = 0.012).