Effects of dorzolamide/timolol and tafluprost on intraocular pressure and pupil diameter in healthy dogs

Abstract

ABSTRACT: This study aimed to evaluate and compare the effects of the fixed combination of dorzolamide/timolol with those of tafluprost on intraocular pressure (IOP) and pupil diameter (PD) in healthy dogs (n=10). Two experiments were conducted with an interval of 30 days. In both, IOP and PD were assessed at 8, 11, 14, 17, and 20h. Parameters were evaluated during baseline, treatment period of four days, and one day of post-treatment. During treatment phase, IOP decreased by 0.74 (P<0.05), 1.88 (P<0.01), 2.94 (P<0.001), and 3.10mmHg (P<0.01), in dorzolamide/timolol-treated eyes; and by 1.50, 2.18, 2.14, and 2.18mmHg (P<0.001), in tafluprost-treated eyes. PD decreased by 0.24 (P<0.01), 0.32 (P<0.01), 0.49 (P<0.001), and 0.40mm (P<0.001), in dorzolamide/timolol treated eyes; and by 2.31, 2.55, 2.43, and 2.70mm (P<0.001), in tafluprost-treated eyes. Dorzolamide/timolol and tafluprost were able to decrease IOP and PD in healthy dogs. However, a cumulative effect of the fixed combination of dorzolamide/timolol was more effective in reducing IOP, than tafluprost. Comparisons between treatments showed that tafluprost was more effective in reducing PD throughout the treatment phase.