Viscocanalostomy versus trabeculectomy in white adults affected by open-angle glaucoma - A 2-year randomized, controlled trial

Purpose: To compare the effectiveness and safety of viscocanalostomy and trabeculectomy in adults with uncontrolled open-angle glaucoma. Design: Single-masked, parallel-group, prospective, randomized 24-month trial, with 90% power to detect a clinically important difference between groups. Participants: Fifty consecutive patients (50 eyes) with primary open-angle or pseudoexfoliative glaucoma. Intervention: Eyes were assigned randomly to either viscocanalostomy (group 1) or trabeculectomy (group 2) with no intraoperative antifibrotics in the study eye. In group 1 no further intervention was allowed, whereas trabeculectomy eyes could receive subconjunctival 5-fluorouracil (5-FU) injections or laser suture lysis after surgery. Main Outcome Measures: Success rate based on intraocular pressure (IOP), visual acuity, discomfort, and other complications. Results: At the end of the 24-month follow-up, IOP of 21 mmHg or less and more than 6 mmHg was achieved in 76% in group 1 (n = 19) and in 80% in group 2 (n = 20; log-rank P = 0.60); an IOP between 6 and 16 mmHg was obtained in 56% in group 1 (n = 14) and in 72% in group 2 (n = 18; log-rank P = 0.17; Kaplan-Meier cumulative probability of success). Complications of viscocanalostomy included one intraoperative conversion into trabeculectomy; microruptures in Descemet's membrane in five eyes; three cases of iris incarceration in the Decemet's window, two of which caused early failure of the procedure requiring reoperation; and a 1-mm to 2-mm transient self-resolving hyphema in three cases. Complications of trabeculectomy included one case of postoperative bleb bleeding with early transient IOP spike; one early hyphema; five cases of postoperative hypotony, two of which had a positive Seidel test from the conjunctival suture; three cases of transient choroidal detachment, two of which had shallow anterior chamber. No patient required reoperation: Two eyes required argon laser suture lysis, and nine underwent one or more 5-FU injections, which caused punctate keratopathy in three eyes. Conclusions: Viscocanalostomy is an effective IOP-lowering procedure in white adults affected by open-angle glaucoma. Trabeculectomy with postoperative 5-FU can probably provides lower IOPs but, with more numerous complications, greater discomfort, and more intensive postoperative management.