Анотация: OBJECTIVE To determine whether 2- or 3-times-daily application of topical ophthalmic 0.005 PROCENT latanoprost solution is more effective at lowering intraocular pressure (IOP) in clinically normal dogs. ANIMALS 9 clinically normal dogs. PROCEDURES For each dog, 1 drop of latanoprost 0.005 PROCENT solution was applied to 1 eye every 8 or 12 hours each day for 5 days; the contralateral eye received topical ophthalmic treatment with 1 drop of saline (0.9 PROCENT NaCI) solution at the times of latanoprost application. Ocular examinations of both eyes were performed every 6 hours starting 48 hours prior to and ending 42 hours after the treatment period. Following a 5-week washout interval, the procedures were repeated but the previously latanoprost-treated eye of each dog received latanoprost application at the alternate frequency. RESULTS Mean с SD IOP reduction in the latanoprost-treated eyes was 31 с 6.9 PROCENT with 2-times-daily application and 33 с 8.2 PROCENT with 3-times-daily application. A 2-way repeated-measures ANOVA revealed significant differences in IOP with contributions by treatment (2 or 3 times daily), time of day (diurnal variation), and individual dog. The maximum mean daily IOP reduction in latanoprost-treated eyes was detected on day 3 of latanoprost treatment in each group. Eyes treated 3 times daily had significantly smaller pupil diameter and greater conjunctival hyperemia than eyes treated 2 times daily. CONCLUSIONS AND CLINICAL RELEVANCE The clinical importance of the ocular hypotensive effects of 3-times-daily topical ophthalmic application of 0.005 PROCENT latanoprost solution in dogs with glaucoma warrants investigation