LAUSR

OBJECTIVE To evaluate the efficacy of 2% dorzolamide ophthalmic solution for reduction of postoperative ocular hypertension (POH) following routine phacoemulsification surgery in dogs. ANIMALS STUDIED Thirty one dogs (53 eyes) with naturally occurring cataracts undergoing routine phacoemulsification surgery. PROCEDURE(S) A prospective, double-masked, randomized, placebo-controlled study design was utilized. Dogs received 2% dorzolamide ophthalmic solution or saline 1 h prior to surgery then three times daily for 21 days postoperatively in the operated eye(s). Intraocular pressure (IOP) was recorded 1 h prior to surgery and 3 h, 7 h, 22 h, 1 week and 3 weeks postoperatively. Statistical analyses were performed using chi-squared and Mann-Whitney U test with a significance level of p < .05. RESULTS Postoperative ocular hypertension (IOP ≥25 mmHg, <24 h after surgery) occurred in 28/53 (52.8%) eyes. There was significant reduction in the incidence of POH for eyes receiving dorzolamide (10/26 (38.4%) eyes) versus eyes receiving placebo (18/27 (66.7%) eyes) (p = .0384). Animals were followed for a median of 163 days after surgery. Thirty-seven (37/53 (69.8%)) eyes were visual at final examination and 3/53 (5.7%) globes were enucleated postoperatively. At last follow-up, there was no difference in visual status (p = .9280), need for topical IOP lowering medication (p = .8319) or incidence of glaucoma (p = .5880) based on treatment group. CONCLUSIONS Perioperative administration of topical 2% dorzolamide reduced the incidence of POH after phacoemulsification in the dogs studied. However, this was not associated with differences in visual outcome, incidence of glaucoma or need for IOP-lowering medications.