Better IOP control with trabeculectomy than with viscocanalostomy

LONDON — Intraocular pressure control was better with trabeculectomy than with viscocanalostomy in a study here. Complications were more frequent with trabeculectomy, but no sight-threatening complications occurred with either technique, researchers at St. Thomas' Hospital found.

In 50 eyes with open-angle glaucoma, 25 were randomized to undergo trabeculectomy and 25 to viscocanalostomy. Those undergoing trabeculectomy were given intraoperative antimetabolites. Antimetabolites were not used intraoperatively in the viscocanalostomy eyes, but those eyes were randomized to the use of viscoelastic or saline for intracanalicular injection.

Mean follow-up was 19 months. At 12 months, complete success — defined as an IOP of less than 21 mm Hg without medication — was accomplished in 100% of the eyes undergoing trabeculectomy, but only in 64% of the eyes undergoing viscocanalostomy.

Eyes that underwent trabeculectomy had a lower mean IOP, and the number of eyes with IOPs of less than 15 mm Hg was greater in the trabeculectomy group. In eyes that had undergone viscocanalostomy, the mean IOP at 12 months was lower in eyes that received viscoelastic than those that received saline.

Transient complications such as early bleb leak and hyphema were more common in the trabeculectomy group than in the viscocanalostomy group (P < .05). Postoperative cataract formation was more common after trabeculectomy as well (P < .05).

The study appears in the July issue of British Journal of Ophthalmology.