Study Finds Trabeculectomy Superior to Canaloplasty in Reducing IOP, But Riskier

The similar rate of visual field progression seen in both subsets of patients suggested both procedures provided comparable long-term control of IOP, likely contributing to a similar rate of structural and functional decline.  Photo: Justin Schweitzer, OD. Click image to enlarge. Glaucoma currently has many avenues of intervention. Surgically, trabeculectomy and canaloplasty are options for open-angle glaucoma, with each performing a bit differently in safety and efficacy. Researchers recently assessed the long-term outcomes of both procedures from the cohort part of the Trabeculectomy vs. Canaloplasty study, following up after 11 years from the original investigation.This study included 15 trabeculectomy and 13 canaloplasty patients, with a mean follow-up time of 11.9 and 11.0 years, respectively. Primary endpoints were complete (without glaucoma meds) and qualified (with or without glaucoma meds) success, defined by either of the following:Definition 1: IOP ≤18mm HgDefinition 2: IOP ≤21mm Hg with ≥20% reduction from baseline. Secondary endpoints included IOP changes, medication use, complication and revision surgery.Complete success rates for trabeculectomy were 53.3% (Definition 1) and 46.7% (Definition 2); these rates were 15.4% and 15.4% for canaloplasty, respectively. Qualified success rates for trab procedures were 73.3% (Definition 1) and 66.7% (Definition 2), while in canaloplasty subjects the rates were 69.2% and 76.9%, respectively. A median post-op IOP of 10.0mm Hg was observed for trabeculectomy and 14.0mm Hg for canaloplasty. Mean number of meds used was also less for trabs (1.0 vs. 1.9). However, the only long-term complication—hypotony maculopathy—occurred exclusively in two trabeculectomy patients (15.4%).Overall, trabeculectomy was found superior in terms of reducing IOP and cumulative complete success for Definition 1, but with no difference in complete success for Definition 2. Both options effectively lowered IOP. However, this came at the cost of increased complication risk, as the two hypotony maculopathy cases were seen with the trab procedures. In their paper on the work, the authors posit that, “for patients with moderately low target IOPs who can tolerate some glaucoma medication use, [canaloplasty] remains a reliable and safer alternative.”In this investigation trabeculectomy also displayed superior surgical success, with 66.4% complete success vs. 24.3% for canaloplasty.With these findings and taking previous literature into account, the researchers believe that “our results support evidence-based surgical recommendations, demonstrating that both procedures remain widely used after 11 years, underscoring the challenge of new alternatives and trabeculectomy’s enduring relevance in glaucoma surgery.”Click here for the journal source. Verma-Fuehring R, Matlach J, Klink T, Hillenkamp J, Grehn F. Long-term outcomes of trabeculectomy versus canaloplasty in open-angle glaucoma – an 11-year follow-up of the TVC study cohort. BMC Ophthalmol. 2025;25:340.