Two-year outcomes of anterior versus posterior scleral application of mitomycin C-soaked sponge in trabeculectomy.

Purpose: To compare the safety and efficacy of two different application methods of mitomycin C (MMC)-soaked sponge in trabeculectomy.

Study design: Retrospective study.

Methods: We included 71 eyes of 71 patients that had undergone trabeculectomy. In the anterior scleral application group, 36 eyes were treated using the long side of the MMC-soaked sponge placed parallel to the limbus. The efficacy and safety in these eyes were compared with eyes treated with the posterior scleral application group, consisting of 35 eyes treated with the long side of the MMC-soaked sponge placed perpendicular to the limbus. The follow-up period was 2 years. The safety of the procedure, including bleb morphology and complications, was the primary outcome, while the success rate was the secondary outcome.

Results: The cumulative success rate at 2 years postoperatively was 94.4% in the anterior and and 94.3% in the posterior scleral application group (P = 1.000). However, with the posterior scleral application of the MMC-soaked sponge, blebs were more low-lying (P = 0.048), less in extent (P < 0.001), more normally vascularized (P = 0.027) and more posteriorly directed (P < 0.001). Furthermore, the incidence of thin-walled cystic bleb (P = 0.028) and bleb leakage (P = 0.025) was significantly lower in the posterior scleral application group than in the anterior group.

Conclusion: Although there were similar success rates, the posterior scleral application of MMC-soaked sponge with trabeculectomy was safer with a better bleb morphology than the anterior scleral application.