Objective: The aim of this study was to compare the efficacy of bimatoprost 0.03% with brimonidine 0.2% in preventing intraocular pressure (IOP) elevations after neodymium:yttrium–aluminum–garnet (Nd:YAG) laser posterior capsulotomy.

Methods: In this prospective, randomized, double-masked study, 195 eyes of 195 consecutive patients who had YAG laser capsulotomy for posterior capsule opacification were recruited. Eyes received either 1 drop of bimatoprost 0.03% (98 patients) or brimonidine 0.2% (97 patients) at 1h before laser surgery. A masked observer measured IOP by Goldmann applanation tonometry before treatment and after treatment at 1h, 3h, 24h, and 7 days. Inflammation was evaluated after surgery. Formation of cystoid macular edema was assessed by measuring the macular thickness before and after laser surgery.

Results: The average peak of postoperative IOP elevation was 2.2±3.9mm Hg in the bimatoprost 0.03% and 3.6±3.1mm Hg in the brimonidine 0.2% group. The difference was statistically significant (P<0.001). Postoperative IOP elevations of 10mm Hg or more occurred in 1 eye (1.56%) in the bimatoprost 0.03% group and 5 eyes (7.35%) in the brimonidine 0.2%. This difference was statistically significant (P<0.001). Macular edema and anterior chamber reaction were not observed related to bimatoprost. No clinically significant side effects were noted in either group.

Conclusions: Our results indicate that prophylactic use of bimatoprost 0.03% is more effective than brimonidine 0.2% in preventing IOP elevation immediately after YAG laser capsulotomy. Bimatoprost 0.03% as a prostamide analog may provide new option for preventing IOP elevation after YAG laser capsulotomy.