Efficacy and safety of penetrating canaloplasty versus ab externo canaloplasty for primary open‐angle glaucoma: A randomized controlled trial

Abstract Purpose To report the 2‐year efficacy and safety of penetrating canaloplasty versus ab externo canaloplasty for the treatment of primary open‐angle glaucoma (POAG). Setting A single surgical site in China. Design This was a prospective, randomized controlled trial. POAG patients were randomly assigned to the penetrating canaloplasty or ab externo canaloplasty group. Methods This study enrolled POAG patients who underwent penetrating canaloplasty or ab externo canaloplasty randomly. Surgical success, intraocular pressure (IOP), number of glaucoma medications, and surgical complications were evaluated until 24 months post‐operatively. Surgical success was defined as 6 mmHg ≤ IOP ≤21 mmHg with an IOP reduction ≥20%, which included qualified success (with or without medications) and complete success (without medications). Results A total of 52 eyes (45 patients) were randomly assigned to one of two groups: the penetrating canaloplasty group (PCP, n = 26) or the ab externo canaloplasty group (CP, n = 26). The probabilities of qualified success and complete success were 92.3% and 76.9%, respectively, in the PCP group and 64.1% and 52.1%, respectively, in the CP group at 24 months ( p = 0.013, p = 0.042, log‐rank test). The mean IOP decreased from 30.8 ± 10.7 and 28.6 ± 11.8 mmHg to 14.1 ± 3.3 mmHg in the PCP group and 22.1 ± 13.6 mmHg in the CP group at year two ( p = 0.007). The PCP group also received fewer medications (0.2 ± 0.5) than did the CP group (0.7 ± 1.2) at year two ( p = 0.038). Post‐operative complications were similar, and the most common complications were transient IOP elevation and hyphema in the PCP group (42.3%, 46.2%) and the CP group (38.5%, 23.1%) ( p > 0.05). Conclusions Compared to ab externo canaloplasty, penetrating canaloplasty had a greater surgical success rate and better IOP reduction with a comparable rate of complications.