Abstract
PURPOSE: To establish preoperative thresholds of intraocular pressure (IOP) levels and the number of IOP-lowering eye drops that predict the surgical success of canaloplasty. METHODS: This retrospective study included 166 glaucoma patients undergoing canaloplasty. Data on age, sex, glaucoma subtype, visual acuity, IOP, number of IOP-lowering eye drops, intraoperative and postoperative complications, and reoperations were collected during a 12-month follow-up period. Logistic regression models were applied to identify preoperative thresholds associated with an increased risk of surgical failure. RESULTS: At 12 months, mean IOP decreased from 24.2 ± 7.8 to 14.8 ± 3.7 mmHg, and the number of IOP-lowering eye drops from 2.3 ± 1.1 to 0.6 ± 1.0 (both p < 0.001). For success rates ≤ 18 and ≤ 15 mmHg, logistic regression identified a preoperative IOP threshold of 36.9 and 27.1 mmHg (qualified success), and 27.1 and 20.1 mmHg (complete success), respectively, above which the likelihood of surgical failure increased. No significant association was found between the number of preoperative IOP-lowering eye drops and surgical success. No long-term postoperative complications were recorded. CONCLUSIONS: In patients with preoperative IOPs of ≤ 36.9 mmHg or 27.1 mmHg, canaloplasty is likely to be an effective and safe procedure to obtain target pressures ≤ 18 mmHg with or without IOP-lowering eye drops, respectively. These data suggest that preoperative thresholds could help predict postoperative outcomes and improve patient selection for glaucoma surgery.