Purpose: To estimate a risk-benefit ratio by comparing the efficacy of canaloplasty to trabeculectomy exclusively in pseudophakic eyes with primary open angle glaucoma.
Patients and methods: One hundred four eyes that underwent ab externo canaloplasty and 136 eyes that underwent trabeculectomy with mitomycin C 0.02% and collagen matrix implantation were retrospectively compared. The efficacy was evaluated by evaluating the absolute success rate (5 ⩽ intraocular pressure ⩽ 15 mmHg) and the qualified success rate (intraocular pressure ⩽15 mmHg) using the Kaplan-Meier survival analysis. A meta-analysis to evaluate the relative risk of both procedures in relation to post-operative interventions was performed.
Results: Mean intraocular pressure was significantly lower in both groups. Intraocular pressure decreased by 32.17% in the canaloplasty group and by 55.04% in the trabeculectomy group at 12 months (analysis of variance, p < 0.001). Medication use was lower in both groups (analysis of variance, p < 0.001) by the 12th month. The absolute success rate for canaloplasty was 20.19% of eyes compared to 52.21% of eyes with trabeculectomy (p < 0.0001). The qualified success rate was not statistically different between groups (p = 0.15). The relative risk ratio was not statistically different between groups (relative risk of 0.01 and weight of 49.65% for group A and relative risk of 0.0005 and weight of 50.35% for group B; p = 0.5). The hospitalization length was longer in trabeculectomy-treated patients (t-test, p < 0.0001).
Conclusion: The trabeculectomy group showed better results in terms of absolute success rate. However, canaloplasty may provide a better risk-benefit ratio in terms of qualified success rate, hospitalization time, and required post-operative interventions, since canaloplasty yielded equal or superior results compared to trabeculectomy.
Keywords: Open angle glaucoma; anti-fibrotic agents; glaucoma incisional surgery; hypotony; post-operative glaucoma; surgery with high-risk ocular conditions.