Objective: To compare the intraocular pressure (IOP)-lowering effect of combined viscocanalostomy and phacoemulsification and combined trabeculectomy and phacoemulsification with mitomycin C in eyes with primary open-angle glaucoma.

Methods: Prospective randomized 1-year trial. Methods: Forty consecutive patients (40 eyes) with primary open-angle glaucoma and cataract. Methods: Eyes were assigned randomly either to trabeculectomy with mitomycin C or to viscocanalostomy in combination with phacoemulsification and intraocular lens implantation. Methods: Success rate based on IOP.

Results: Mean baseline IOP was 24.0+/-2.0 mmHg in the viscocanalostomy group and 23.7+/-2.6 mmHg in the trabeculectomy group (P = 0.7). Mean postoperative IOP was 13.7+/-2.2 mmHg at 3 months, 14.8+/-3.3 mmHg at 6 months, and 14.9+/-3.0 mmHg at 12 months in the viscocanalostomy group and 12.1+/-4.0 mmHg at 3 months, 13.8+/-4.7 mmHg at 6 months, and 14.1+/-4.4 mmHg at 12 months in the trabeculectomy group. There was no significant difference in the mean IOP between the groups at any time. At 12 months, 17 patients (85%) in the viscocanalostomy group and 16 patients (80%) in the trabeculectomy group achieved an IOP of 20 mmHg or less without medication (P = 0.7). Complications included 2 cases (10%) of flat/shallow anterior chamber and 4 cases (20%) of hypotony in the trabeculectomy group, whereas intraoperative microperforation of Descemet's membrane occurred in 3 cases (15%) in the viscocanalostomy group.

Conclusions: There was no significant difference in IOP reduction between viscocanalostomy and trabeculectomy with mitomycin C in combination with phacoemulsification and intraocular lens implantation in patients with primary open-angle glaucoma.