AIM: To compare the effectiveness of brimonidine/timolol fixed combination (BTFC) and dorzolamide/timolol fixed combination (DTFC) in the management of short-term intraocular pressure (IOP) increase after phacoemulsi?cation surgery.METHODS: Eighty eyes of 80 patients undergoing phacoemulsi?cation and intraocular lens (IOL) implantation were randomly assigned into three groups. Group 1 consisted of 28 eyes and represented the control group. Group 2 consisted of 25 eyes undergoing phacoemulsi?cation surgery and BTFC was instilled at the end of surgery. Group 3 consisted of 27 eyes undergoing phacoemulsi?cation surgery and DTFC was instilled at the end of surgery. IOP was measured preoperatively and 6, 24h and 1wk postoperatively.RESULTS: There was no statistically signi?cant difference in preoperative baseline IOP among the three groups (P=0.84). However, IOP was significantly lower in groups 2 and 3 compared to the control group (P<0.05 for all comparisons) at all postoperative visits. There was no significant difference between groups 2 and 3 at any visit. Eight eyes (28.6%) in the control group, two (8%) in Group 2 and one (3.7%) in Group 3 had IOP >25 mm Hg at 6h after surgery (P=0.008). However, IOP decreased and was >25 mm Hg in only one eye in each group at 24h after surgery.CONCLUSION: BTFC and DTFC have similar effects in reducing increases in IOP after phacoemulsification surgery and can both be recommended for preventing IOP spikes after such surgery.