Is canaloplasty with mitomycin c a safe procedure in myopic glaucoma?

PURPOSE: Myopic glaucoma patients display a considerable risk of complications following antiglaucomatous filtering surgery, e.g., trabeculectomy. Canaloplasty with mitomycin C may reduce this risk by avoiding massive overfiltration. METHODS: We performed retrospective analysis of 31 eyes with myopia that underwent canaloplasty modified with mitomycin C in a consecutive single-surgeon case series. Annual data and success rates were analysed. Twenty-three myopic eyes that had received conventional trabeculectomy with mitomycin C were recorded as a comparison. RESULTS: The 31 eyes with a follow-up of 40 ± 26 months after canaloplasty had a mean spherical equivalent of − 8.4 ± 4.5 dioptres. Intraocular pressure decreased from 32.3 ± 9.6 mmHg (range: 17 to 58) to 16.8 ± 8.1 mmHg (range: 5 to 44) 1 year after surgery (− 46%; p < 0.001) with a medication score reduction from 5 to 1.2 (p < 0.001). Qualified success rates (Criterion B: no revision surgery, IOP < 21 mmHg, IOP reduction > 20%) were 83% after 1 year and 61% at the 2nd and 3rd years. In 5 eyes (16%), early ocular hypotony (≤ 5 mmHg) was observed. Two eyes (7%) showed transient choroidal detachment and swelling. The 23 eyes that had received trabeculectomy had success rates (Criterion B) of 91% at the 1st and 86% at the 2nd and 3rd years. Hypotony occurred in 10 eyes (44%), and 4 eyes (17%) showed choroidal detachment or macular folds. CONCLUSIONS: Postoperative complications related to overfiltration were less frequent after canaloplasty with mitomycin C. Midterm data proved good efficacy. Pressure reduction, success rates and rates of medication free patients were significantly higher in trabeculectomy compared to modified canaloplasty with mitomycin C.