Circumferential viscodilation and tensioning of Schlemm's canal is a safe and effective surgical procedure for reducing intraocular pressure (IOP) in adult patients with open-angle glaucoma (OAG), according to the results published in the July issue of the Journal of Cataract and Refractive Surgeons.

Richard Lewis and colleagues from across the US and Germany conducted an international, multicentre, prospective study of adult patients with OAG with a preoperative IOP of at least 16 mmHg.

Following a non-penetrating dissection technique to expose Schlemm's canal, a flexible microcatheter was used to dilate the full circumference of the canal by injecting sodium hyaluronate 1.4% during catheterization. A suture loop was placed in the canal to apply tension to the trabecular meshwork.

High-resolution ultrasound imaging was used to assess Schlemm's canal and anterior segment angle morphology, including distension of the trabecular meshwork caused by the tensioning suture. Data analysis was performed in two groups: Group 1 included patients that met all inclusion criteria (94) and Group 2 was made up of Group 1 patients who had successful suture placement (74).

Mean baseline IOP in Group 1 was 24.7 mmHg±4.8 on a mean of 1.9±1.0 medications per patient. In Group 2, the mean IOP was 16.1±4.7 mmHg three months postoperatively, 15.6±4.0 mmHg at six months and 15.3±3.8 mmHg at one year. Medication use was down to 0.6±0.9 per patient by the 12-month mark.

Surgical and postoperative adverse events were noted in 15 of the 94 patients and included: hyphema (3), elevated IOP greater than 30 mmHg (3), Descemet's tear (1), hypotony (1), choroidal effusion (1) and exposed closure suture with eyelid oedema and erythema epiphora (1).

The authors of this study conclude that viscodilation and tensioning of Schlemm's canal is a safe and effective procedure.