Medical control of intraocular pressure with brinzolamide 1% after phacoemulsification

Background: To compare the effectiveness of only 1 drop of topical brinzolamide 1% with dosing every 12 hours and with no ocular hypotensive medication following clear corneal phacoemulsification surgery.Methods: This prospective, randomized, double-blind study was composed of 60 eyes of 60 patients who underwent uneventful clear corneal phacoemulsification surgery under topical anesthesia. There were no intraoperative complications. Eyes were randomized to receive only 1 drop of topical brinzolamide 1% immediately after surgery, 1 drop of brinzolamide 1% every 12 (q12h) hours starting immediately after speculum removal, or no ocular hypotensive medication (control group). Intraocular pressure (IOP) was measured preoperatively and at 4 to 6 hours and 18 to 24 hours postoperatively by a Perkins tonometer.Results: Preoperative IOP was not significantly different among the 3 groups. IOPs of both the brinzolamide 1 drop group (p = 0.000) and the brinzolamide q12h group (p = 0.001) were significantly lower than those of the control group at 4 to 6 hours postoperatively. The same result was observed at 18 to 24 hours postoperatively in the brinzolamide q12h group (p = 0.001) but not the brinzolamide 1 drop group (p = 0.489). The brinzolamide q12h group had significantly lower IOP compared with the brinzolamide 1 drop group (p = 0.000) at 18 to 24 hours postoperatively. None of the eyes in the medication groups, but 1 eye (5%) in the control group, had postoperative IOP elevation ≥30 mm Hg at 4 to 6 hours; such an elevation was not encountered at postoperative 18 to 24 hours. Preoperative to postoperative IOP increase of >5 mm Hg at 4 to 6 hours postoperatively was seen in 4 (20%), 4 (20%), and 14 (70%) eyes in the brinzolamide 1 drop group, the brinzolamide q12h group, and the control group, respectively.Interpretation: The current study reveals that 1 drop of brinzolamide 1% is sufficient to control IOP within the first 4 to 6 hours following uneventful phacoemulsification, whereas 12-hour dosing is necessary for prolonged control of IOP.