Combined Ab interno viscocanaloplasty (ABiC) in open-angle glaucoma: 12-month outcomes

Purpose: The aim of this study was to analyse the safety profile and efficacy of ab interno viscocanaloplasty (ABiC) through to 12 months post-operatively. Methods: In this retrospective study, the medical records of all patients who underwent ABiC between September 2015 and December 2019 were analysed. Complete success was defined as a 12-month reduction in intraocular pressure (IOP) ≥ 20% from baseline with no concomitant medications. Qualified success criteria were identical, with no more medications than at baseline. Results: In all, 54 eyes of 41 patients were analysed. Mean IOP decreased from 23.6 ± 7.4 mmHg preoperatively to 14.2 ± 2.9 mmHg (-39.8%; p < 0.001) after 12 months. Concomitantly, the number of anti-glaucoma treatment dropped from 2.9 ± 1.0 to 0.6 ± 1.1 (-79.3%; p < 0.001). Amongst patients with a baseline MD < -12.0 dBs, mean IOP decreased from 22.8 ± 9.8 mmHg to 13.8 ± 4.4 mmHg (p = 0.049), with a concomitant reduction of medications from 2.8 ± 1.3 to 1.2 ± 1.3 (p < 0.001). Complete success at 12 months was achieved in 46% of eyes, and qualified success was achieved in 65% of eyes. Amongst eyes with a baseline MD < -12.0 dBs, 50% achieved complete success, and 83.3% achieved qualified success. A total of 19 eyes (35.2%) were considered surgical failure, all due to uncontrolled IOP. Of them, 7 eyes (13.0%) required further filtering surgery. Twelve post-operative adverse events were observed, with early post-operative IOP spikes being the most common (22.2%). Conclusions: ABIC achieved a statistically significant reduction in IOP and anti-glaucoma medications through 12 months, while maintaining a favourable safety profile in mild-to-severe open-angle glaucoma.