One-Year Randomized Comparison of Safety and Efficacy of Trabeculectomy with Mitomycin C Sub-Tenon Injection versus Mitomycin C-Infused Sponges

Abstract

To compare the safety and efficacy of sub-Tenon injection of mitomycin C (MMC) with application of MMC-infused sponges during trabeculectomy. Single-center randomized clinical trial. A total of 56 eyes of 49 patients with open-angle glaucoma were included in this clinical trial. In this single-center randomized clinical trial, 56 eyes of 49 patients underwent trabeculectomy with MMC for primary open-angle glaucoma. Patients were randomized into 2 groups. The injection group received a sub-Tenon injection of 0.15 ml of 0.01% MMC diluted with preservative free lidocaine 2% (n= 27). In the sponges group, sponges soaked in 0.02% MMC were applied under the Tenon's capsule and the scleral flap for 2 minutes (n= 29). Intraocular pressure, endothelial cell count, best-corrected visual acuity, and number of intraocular pressure (IOP)-lowering medications were assessed before surgery and 1 week; 1, 3, and 6 months; and 1 year after surgery. Complete success was defined as IOP of 14 mmHg or less without medication. Bleb morphologic features were assessed using the Indiana Bleb Appearance Grading Scale bleb grading system. Intraocular pressure reduction was the primary outcome. Bleb morphologic features and endothelial cell counts (ECCs) were secondary outcomes. Mean IOP in the sponges group decreased from 30.5 ± 7.4 mmHg at baseline to 12.6 ± 5.9 mmHg at 1 year (P < 0.001); in the injection group, IOP decreased from 29.3 ± 6.8 mmHg at baseline to 12.7 ± 4.3 mmHg at 1 year (P < 0.001). No difference in IOP between the 2 groups was noted at any visit (P < 0.001). Surgical success was 81.5% and 82.8% in the injection and sponges groups, respectively, at 1 year. Mean ECC values were unchanged from baseline to 1 year after surgery for both groups (P= 0.444). Complication rates were similar in the 2 groups. Bleb morphologic features showed differences in the appearance and grading of the blebs between the 2 groups at 1 year, showing larger extent, lower height, and less vascularization in the injection group. Sub-Tenon injection of MMC during trabeculectomy seems to be as safe and as efficacious as conventional application of MMC with sponges at 1 year after surgery. Bleb morphologic features show notable differences that may suggest a better long-term outcome.