Ab Externo Canaloplasty Alone or Combined with Phacoemulsification for Advanced Primary Open-Angle Glaucoma.

Advanced primary open-angle glaucoma (POAG) requires surgical strategies that achieve effective reduction of intraocular pressure (IOP) while preserving optic nerve structure and function. This study aims to compare the long-term clinical performance of ab externo canaloplasty (AC) alone versus AC combined with phacoemulsification (AC + phaco) in patients with advanced POAG. In this retrospective comparative study, 140 patients with advanced POAG were assigned to AC (n = 70) or AC + phaco (n = 70). Over 24 months of follow-up, both procedures significantly reduced IOP and medication use. However, AC + phaco achieved greater mean IOP reduction (45.5% vs. 36.1%; p < 0.001), higher retinal nerve fiber layer thickness (62.55 ± 6.03 µm vs. 60.82 ± 6.51 µm; p = 0.047), larger neuroretinal rim area (0.91 ± 0.12 mm² vs. 0.85 ± 0.12 mm²; p = 0.009), and improved visual field stability. Quality-of-life measures favored AC + phaco, with improved patient-reported visual function and fewer vision-related limitations. These findings demonstrate that both AC and AC + phaco are safe and effective surgical options for advanced POAG. AC + phaco may be preferentially selected in patients with coexisting cataract or in cases requiring enhanced long-term IOP control and structural preservation, without increasing surgical risk.