Abstract: Objective To evaluate the long-term efficacy and safety of ab externo microcatheter-assisted trabeculotomy (MAT) for primary open-angle glaucoma (POAG). Design Retrospective case series. Participants Consecutive 47 patients (63 eyes) with POAG who underwent ab externo MAT from October 2015 to May 2018 by a single surgeon in Beijing Tongren Eye Center. Methods Patients were followed before and 1, 3, 6 months, 1, 2, 3, 4, 5 years after surgery. Intraocular pressure (IOP) and usage of anti-glaucoma medication were compared between before surgery and last visit after surgery. Surgical success was defined as a postoperative IOP of ≤21 mmHg with (qualified success) of without (complete success) the use of anti-glaucoma medication. According to anti-glaucoma surgery history the patients were divided into two groups and compared IOP and usage of medication between two groups. Main Outcome Measures IOP, number of anti-glaucoma drops, surgery successful rate, and the complications. Results The pre-operative IOP was (24.8±9.0)mmHg, and post-operative IOP was（16.9±4.7）（P=0.000）. And the pre-operative number of anti-glaucoma drops was (2.9±0.9), post-operative was （0.7±1.0）（P=0.000）. The 1-, 3-, and 5-year cumulative rate of complete success was 72.1%, 62.7% and 41.2%, and those of qualified success was 91.8%, 88.1% and 76.5%, respectively. Hyphema was seen in all eyes and part of patients had transient IOP fluctuation in early postoperative days. There were no severe complications occurred in long-term follow-up. The last follow-up IOP with and without anti-glaucoma surgery history was repectively (18.1±5.1) mmHg and (15.7±4.0) mmHg（P=0.098）. Anti-glaucoma surgery history did not affect the surgery results. Conclusion Ab externo MAT has long-term effectiveness and safety for POAG. Previous anti-glaucoma surgery does not affect the results of MAT surgery. (Ophthalmol CHN, 2021, 30: 435-439)

Key words: ab exgerno microcatheter-assisted trabeculotomy, primary open-angle glaucoma