Circumferential Viscocanalostomy and Suture Canal Distension (canaloplasty) for Whites with Open-angle Glaucoma

Purpose: To assess the safety and efficacy of canaloplasty (360-degree viscodilation and tensioning of the Schlemm canal) in Whites with open-angle glaucoma (OAG).

Methods: In a prospective study, 32 consecutive patients with medically uncontrolled OAG underwent primary canaloplasty with a follow-up time of more than 1 year. Laser goniopuncture was performed if postoperative intraocular pressure (IOP) was above 16 mmHg. IOP, number of antiglaucomatous medications, best-corrected visual acuity, and intraoperative and postoperative complications were recorded. Complete success was defined as an IOP ≤21, 18, and 16 mm Hg without medications, and qualified success with or without medications, respectively.

Results: The mean IOP dropped from 27.3±5.6 mm Hg preoperatively to 12.8±1.5 mm Hg at 12 months and 13.1±1.2 mm Hg at 18 months (P<0.001). The complete success rate of an IOP ≤21, 18, and 16 mm Hg was 93.8% [95% confidence interval (CI) 0.86-1.0], 84.4% (95% CI 0.73-0.98), and 74.9% (95% CI 0.61-0.92), respectively, at 12 months. Laser goniopuncture was performed on 6 eyes (18.1%) 3.3±2.1 months postoperatively. The mean IOP was 20.6±4.2 mm Hg before and 14.2±2.2 mm Hg after goniopuncture. The number of medications dropped from 2.7±0.5 before surgery to 0.1±0.3 after surgery (P<0.001). The postoperative best-corrected visual acuity at last visit (0.38±0.45; range: 0 to 1.8) was comparable with that of preoperative values (0.36±SD 0.37; range: 0 to 1.6) (P=0.42). In all but 1 eye, canaloplasty was completed. Minor intraoperative or postoperative complications like Descemet membrane detachment in 2 eyes, elevated IOP in 1 eye, and suprachoroidal passage of the catheter in 4 eyes were encountered. In 1 eye, circumferential cannulation of the Schlemm canal was impossible.

Conclusions: Canaloplasty seems to be a promising and effective surgical procedure in Whites with OAG. Postoperative IOP levels are in the low-to-mid-teens. The procedure can be regarded as safe, but has its own profile of complications.