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After 11 years, trabeculectomy outperformed canaloplasty in lowering intraocular pressure and reducing medication use but carried a higher complication risk.

An 11-year cohort study published in BMC Ophthalmology evaluating long-term outcomes of trabeculectomy versus canaloplasty (TVC) in open-angle glaucoma shows that trabeculectomy continued to demonstrate better reductions in intraocular pressure even after 11 years as well as higher complete success rates.

The study was a long-term prospective follow-up of the cohort originally enrolled in the 2015 TVC study, which compared the efficacy and safety of trabeculectomy and canaloplasty in patients with open-angle glaucoma. The objective of the follow-up study was to evaluate the long-term outcomes of these procedures and compare them to the 12-month outcomes of the original study.

Primary endpoints included complete success without glaucoma medication and qualified success with or without medication, defined as intraocular pressure of 18 mmHg or less [Definition 1] or intraocular pressure of 21 mmHg or less, with a 20% or greater reduction from baseline [Definition 2]. Secondary endpoints included changes in intraocular pressure, medication usage, complications, and revision procedures.

Mean follow-up duration was 11.9±1.1 years for trabeculectomy and 11.0 ± 2.0 years for canaloplasty, with 15 individuals in the trabeculectomy group and 13 in the canaloplasty group.

Benefits & Drawbacks of Each Approach

Complete success for trabeculectomy versus canaloplasty was 53.3% versus 15.4% [Definition 1; P=0.06] and 46.7% versus 15.4% [Definition 2; P=0.22]. Qualified success rates were 73.3% for trabeculectomy and 69.2% for canaloplasty using Definition 1 and 66.7% for trabeculectomy versus 76.9% for canaloplasty using Definition 2.

Median intraocular pressure was 10.0 mmHg (range, 6.0–12.0) for trabeculectomy and 14.0 mmHg (range, 11.5–17.75) for canaloplasty (P<0.01). The mean number of glaucoma medications used was 1.0±1.4 in the trabeculectomy group and 1.9±1.5 in the canaloplasty group.

Revision procedures were performed in 26.7% with trabeculectomy and 23.1% for canaloplasty. Hypotony maculopathy was the only long-term complication noted in 15.4% of trabeculectomy cases.

The findings indicate that, even after 11 years, both procedures effectively lower intraocular pressure, but trabeculectomy showed better efficacy in decreasing medication use and achieving medication-free outcomes, according to the study results.

“Yet, this comes at the cost of an increased risk of complications, with hypotony maculopathy observed exclusively in [trabeculectomy],” the researchers noted. “For patients with moderately low target [intraocular pressures] who can tolerate some glaucoma medication use, [canaloplasty] remains a reliable and safer alternative.”