Canaloplasty and trabecular bypass glaucoma surgery: indications and outcomes

Trabecular bypass stents and ab interno canaloplasty are popular micro-invasive glaucoma surgery approaches. This review summarizes recent evidence on outcomes, safety, and comparative effectiveness of these procedures.

Five to 7-year studies of the iStent and Hydrus combined with cataract surgery report sustained efficacy, slower visual field progression, and cost-effectiveness versus cataract surgery alone. However, position-related inflammatory and endothelial concerns have emerged for the Hydrus. Canaloplasty via several modalities can achieve intraocular pressure (IOP) reductions of 30-40% and medication reductions up to 60%, through as long as 6  years of follow-up, with few complications. Regarding standalone delivery, prospective data supports the use of the iStent infinite in refractory glaucoma. Standalone canaloplasty evidence is strongest for the OMNI and iTrack devices, while early STREAMLINE device outcomes are promising. Comparative studies find that the Hydrus may outperform earlier-generation iStents but not the iStent infinite; canaloplasty with the STREAMLINE device demonstrates near-equivalence to iStent inject W; and gonioscopy-assisted transluminal trabeculotomy achieves lower IOP than viscodilation, albeit with more frequent hyphema.

Both trabecular bypass and canaloplasty are effective interventions for open-angle glaucoma. Stents have the largest evidence base, while canaloplasty may offer similar efficacy without implant-related concerns.