PURPOSE: To compare long term efficacy of phacoemulsification in the early management of acute primary angle closure (APAC) after aborting an acute attack and performing laser peripheral iridotomy (LPI). METHODS: In this nonrandomized comparative prospective study, we included 35 subjects presenting with APAC who had responded to medical treatment and LPI with intraocular pressure (IOP) less than 25 mmHg. Twenty patients with visually significant cataract with visual acuity of <20/30 were assigned to the Phaco/LPI group and underwent phacoemulsification within 6 weeks of the attack. Fifteen subjects with clear lens were assigned to the LPI Only group and were followed clinically. The primary measured outcome was the prevalence of IOP rise after 1 month (treatment failure), defined as 1) if a patient developed IOP rise resulting in IOP >21 mmHg with or without medication, or 2) if a patient required any medication to have IOP ≤21 mmHg after 1 month. Patients were followed for at least one year. RESULT: IOP, number of medications, gonioscopy grading, and amount of synechiae were not significantly different at baseline between the two groups. Acute attack did not recur in any patient. There was more significant failure in the LPI Only group compared with the Phaco/LPI group (40% vs. 5%; p = 0.02). There was a significant difference in final IOP between the two study groups (13.90 ± 2.17 vs. 17.8 ± 4.16 in the Phaco/LPI and LPI Only groups, respectively; p = 0.001). Patients in the Phaco-LPI group needed less medication than the other group at final follow-up. No serious complications have arisen from the immediate LPI or phacoemulsification. CONCLUSION: Phacoemulsification is a safe procedure for preventing IOP rise after aborting acute primary angle closure if performed within a few weeks of the attack.