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

Abstract

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.

Long-Term Efficacy and Safety of Modified Canaloplasty Versus Trabeculectomy in Open-Angle Glaucoma

“…Trabeculectomy was more efficient in terms of IOP control with a lower IOP at follow-up than after modified Canaloplasty and a significantly better absolute and percentage IOP decrease which was similarly described in previous studies and meta-analyses [ 10 , 18 , 19 , 20 , 22 , 23 , 24 , 25 ]. Brüggemann et al, Matlach et al, and Nassri et al reported non-significant differences in IOP between the two groups after 12 months or beyond; however, IOP was constantly lower in the trabeculectomy groups [ 12 , 16 , 21 ].…”

“…Throughout the follow-up period, every second modified canaloplasty case needed supplemental AGM, whereas 89.3% of trabeculectomy cases did not, and the number of medications was significantly lower after trabeculectomy than after modified canaloplasty. The same trend (either significant or not) was visible in all previous comparative studies [ 12 , 16 , 17 , 18 , 20 , 22 , 23 , 24 , 25 , 26 ] except the study of Brüggemann et al, where none of the canaloplasty cases and three of the trabeculectomy cases were on topical AGM [ 21 ]. The meta-analysis by Zhang et al found that AGM was slightly more reduced after trabeculectomy than after canaloplasty by 0.37 medicaments ( p = 0.11) [ 23 ]; the two other meta-analyses by Liu et al and Rulli et al, however, they did not analyze the number or reduction of AGM [ 10 , 19 ].…”

“…In highly myopic eyes, postsurgical complications, in particular hypotony with subsequent choroidal detachment or hemorrhage, are considered to occur more frequently due to the thin sclera with low rigidity being more likely to collapse [ 30 ]. Although two previous studies did not show a higher risk for failure or complications after trabeculectomy in myopic patients [ 25 , 31 ], canaloplasty might be a safer option since there is no absolute hypotony phase due to the intact Descemet’s membrane.…”