AIM:To investigate the antihypertensive effect and the impact of postoperative complications of different conjunctival flap size in the routine glaucoma trabeculec-tomy. METHODS:The eyes of 10 cases with chronic angle-closure glaucoma underwent conventional trabeculectomy + peripheral iris excision procedure,and the conjunctival fornix flap for the basement,without intraoperative antimetabolites. Equilateral triangle conjunctival flap with the bottom edge of 10mm long and 6mm high was performed in one eye,and the other eye was performed a long-10mm,high-6mm rectangular conjunctival flap (the actual size of the equivalent twice of the former),and the remaining operation steps were the same. From the second day after the operation,the daily measurement of intraocular pressure (IOP) (non-contact tonometer),slit-lamp examination of anterior chamber were performed for seven days until suture removal.RESULTS:The eyes with expanded conjunctival flap in 10 cases all had the occurrence of postoperative shallow anterior chamber of which there were 5 cases with one-stage shallow anterior chamber,4 cases with two-stage shallow anterior chamber,1 case with three-stage shallow anterior chamber. Dyeing:one case of two-stage shallow anterior chamber eyes with conjunctival flap wound leakage; filtration bulb of conjunctival sac intumesce in the bottom of the three-stage shallow anterior chamber eyes. No cilio-choroidal detachment occurred. IOP mea-surement:all IOPs were lower than 4-8mmHg,and the difference between binoculus was less than 2mmHg. One stage and two stage shallow anterior chamber eyes underwent filtering pillow compression and bandaging,and three stage shallow anterior chamber eyes were dilated with Mydrin-P daily,pressuring with filtering pillow and bandaging,without using ocular hypotensive agents orally or intravenously. When removing the suture 7 days after operation,the anterior chambers were normal; binocular IOPs were 14 mmHg in 1 case,less than 10mmHg in 9 cases,the binocular difference was less than 2mmHg,and the sizes of binocular filter bleb were the same. There was no difference in binocular filter bleb and IOP during the half month,one month,and three month review.CONCLUSION:The expansion of the conjunctival flap can not reduce IOP and increase the volume of the filtering bleb effectively,but can increase the occurrence of complications caused by strong filtering,low eye pressure,and large filter bleb. 