Penetrating canaloplasty can successfully control intraocular pressure (IOP) and reduce the need for medication in patients with glaucoma secondary to iridocorneal endothelial syndrome (GS-ICE), according to a study published in the American Journal of Ophthalmology.
Patients (n=29, mean age 47.3±10.7 years, 15 women, 14 men) with GS-ICE were recruited for this prospective, noncomparative clinical study at the Eye Hospital of Wenzhou Medical University in China in 2018. All patients underwent penetrating canaloplasty performed by a single surgeon. Patients were followed for 12 months for changes in IOP and glaucoma medication use.
The patients had a mean, baseline IOP of 39.5±11.8 mm Hg and took a mean 2.9±1.0 glaucoma medications. Their median visual acuity was 20/50 and 24.1% had undergone a previous glaucoma surgery. For most patients in the study, the most common clinical variation of iridocorneal endothelial syndrome (ICE) was progressive iris atrophy (PIA; 41.4%), followed by Chandler syndrome (CS; 34.5%) and Cogan-Reese syndrome (CRS; 24.1%).
The 1-year complete success rate of the procedure was 75.9% and qualified success rate was 82.8%. In general, the inner aqueous outflow was rescued by creating a line of direct communication between the posterior chamber and Schlemm canal.
At 12 months, IOP decreased to 16.6±5.3 mm Hg (P <.001) and the number of glaucoma medications to 0.2±0.6 (P <.001). At the final follow-up (mean, 21.3 months), IOP was 16.8±7.1 mm Hg and the number of medications was 0.3±0.8.
Vision improved in 15 eyes, remained the same in 8 eyes, and worsened in 6 eyes.
Microhyphema occurred in 37.9% of eyes and transient hypotony with or without choroidal detachment in 34.5%. All cases of hypotony spontaneously resolved during the first week after surgical intervention. Five eyes had a postoperative elevation in IOP (>30 mm Hg) which resolved within 3 months.
Postoperative failure was observed among 2 PIA eyes, 2 CS eyes and 1 CRS eye (17.2%).
The research shows penetrating canaloplasty has a high success rate and is able to decrease IOP and glaucoma medication use in GS-ICE eyes. This study may have been limited due to travel distance, some patients received their follow-up exams at local sites, not by the study’s investigators.
The study authors report that the “procedure appears to have a reduced rate of postoperative hypotony and its related complications (5.7%) in comparison to trabeculectomy performed with antimetabolites (10% to 37%). However, the exact mechanism for the IOP lowering effect of penetrating canaloplasty can only be proposed at present.”
Deng Y, Zhang S, Ye W, et al. Achieving inner aqueous drain in glaucoma secondary to iridocorneal endothelial syndrome: One year results of penetrating canaloplasty.Am J Ophthalmol. 2022;S0002-9394(22)00266-5. doi:10.1016/j.ajo.2022.07.006