Objective: The diurnal efficacy and safety of the fixed combinations of latanoprost/timolol given once daily vs dorzolamide/timolol given twice daily in primary open-angle glaucoma or ocular hypertensive patients.

Methods: A double-masked, two-centre, crossover comparison.

Results: In 33 patients, the mean diurnal IOP (0800-2000, measured every 2 h) for latanoprost/timolol fixed combination was 17.3+/-2.2 mmHg and for dorzolamide/timolol, the fixed combination was 17.0+/-2.0 mmHg (P = 0.36). Additionally, there was no statistical difference for individual time points following a Bonferroni correction. A bitter taste was found more frequently with the dorzolamide/timolol fixed combination (n = 6) than the latanoprost/timolol fixed combination (n = 0) (P = 0.040), while the latanoprost/timolol fixed combination demonstrated more conjunctival hyperaemia (n = 9) than the dorzolamide/timolol fixed combination (n = 2) (P = 0.045). One patient was discontinued early from the dorzolamide/timolol fixed combination due to elevated IOP.

Conclusions: This study suggests that the daytime diurnal IOP is not statistically different between the dorzolamide/timolol fixed combination and latanoprost/timolol fixed combination in primary open-angle glaucoma and ocular hypertensive patients.