Wang H, Xin C, Han Y, et al. - Researchers performed a retrospective chart review to compare the effectiveness and safety of ab externo circumferential trabeculotomy (ECT) and canaloplasty on primary open angle glaucoma (POAG) patients with failed filtering surgery and intact schlemm’s canal (SC). The sample consisted of POAG patients with failed filtering surgery and intact SC, who further received ECT and canaloplasty. Twenty-nine eyes in the ECT group and 19 eyes in canaloplasty group were recruited. The postoperative IOP and the number of topical medications reduced significantly in both groups. The prevalence of hyphema in the ECT group was higher than in a canaloplasty group. Canaloplasty can be safer for POAG with failed filtering surgery and intact SC, while ECT presented better IOP control.