Modified canaloplasty with suprachoroidal drainage versus conventional canaloplasty-1-year results

The aim of this study was to investigate the efficacy and safety of a new and modified canaloplasty technique with suprachoroidal drainage in a large patient cohort, and to compare its IOP-lowering and topical drug-sparing effect to that of conventional canaloplasty.

This retrospective clinical trial included patients with open-angle glaucoma or secondary forms of glaucoma who underwent either conventional canaloplasty or canaloplasty with suprachoroidal drainage. Primary endpoint was the IOP reduction after 12 months as well as the number of IOP-lowering medications. Secondary endpoints were intra- and postoperative complications and the occurrence of secondary surgical interventions.

Four hundred and seventeen eyes were included in the study; 180 of them were treated with conventional canaloplasty, and 237 eyes underwent canaloplasty with suprachoroidal drainage. In both groups, a significant IOP reduction could be observed after 12 months. Mean IOP reduction was stronger after canaloplasty with suprachoroidal drainage (35.9 %) (from baseline 20.9 ± 3.5 mmHg to 13.1 ± 2.5 mmHg) than after conventional canaloplasty (31.2 %) (from baseline 20.8 ± 3.6 mmHg to 14.0 ± 2.6 mmHg) (p < 0.01). The number of IOP-lowering medications decreased significantly in both groups: after canaloplasty with suprachoroidal drainage from 3.5 ± 0.9 to 0.7 ± 1.0, and after conventional canaloplasty from 3.4 ± 0.9 to 0.8 ± 0.9 with different drugs. The percentage of patients who were free of IOP-lowering agents after 1 year was significantly higher in the combined group (56.9 %) than in the group of conventional canaloplasty (45.4 %) (p = 0.0383). No serious complications were observed.

The modified surgery technique of canaloplasty with suprachoroidal drainage yields the opportunity to optimize the IOP-lowering effect of canaloplasty as a non-penetrating surgical procedure while still offering a more favourable safety profile than trabeculectomy. The suprachoroidal access facilitates the most complicated step of the canaloplasty surgery: the localization of Schlemm's canal.