Abstract： Objective To investigate the morphological changes of anterior segment in patients with acute primary angle closure glaucoma (APACG) after phacoemulsification using the Pentacam three-dimension anterior chamber analysis system and anterior segment optical coherence tomography (AS-OCT).Methods Thirty- nine APACG patients (39 eyes) accompanied with cataract were treated with phacoemulsification from July 2010 to December 2010 in Zhongshan Hospital.All the patients were examined by Pentacam and AS-OCT preoperation and 3 months postoperation.Outcomes included intraocular pressure (IOP),central anterior chamber depth (CACD),peripheral anterior chamber depth (PACD),anterior chamber volume (ACV),pupil diameter (PD),and anterior chamber angle (ACA) on cross- section photographs.Results Mean IOP decreased from preoperative (33.08 ± 5.21) mm Hg to postoperative (16.36±3.44) mm Hg (1 mm Hg=0.133 kPa,t=20.644,P=0.000) and CACD measurements increased from (1.79±0.20) mm to (3.41±0.38) mm (t=36.191,P=0.000).PACD deepened from (0.82±0.12) mm to (1.81±0.20) mm (t=40.732,P=0.000).ACV increased from (74.10±9.94) mm to (149.72±17.12) mm (t=54.921,P=0.000).Inferior ACA widened from (24.03±3.50)° to (43.29±3.92)° (t=55.489,P=0.000),and from (23.02±2.96)° to (42.36±4.61)° (t=43.291,P=0.000) in nasal direction.Superior ACA widened from (21.62±3.04)° to (39.66±3.53)° (t=43.511,P=0.000),and from (22.88±2.87)° to (41.21±3.81)° (t=44.930,P=0.000) in temporal direction.PD before and after phacoemulsification were (3.06± 1.32) mm and (3.00 ± 1.21) mm (t=1.177,P=0.247) respectively,with no statistic difference.Conclusions Phacoemulsification can widen the angle and lessen angle crowding in APACG patients.The Pentacam and AS-OCT allow easy,fast,automatic and noncontact quantification of the anterior chamber parameters with good prospects.