Subconjunctival Versus Intrascleral Application Of Mitomycin C During Trabeculectomy

Purpose: To compare efficacy and safety between subconjunctival and intrascleral methods of mitomycin C (MMC) application during trabeculectomy Methods: This retrospective study included 165 eyes treated by trabeculectomy and compared clinical outcomes between eyes that received subconjunctival MMC (Group 1, 80 eyes, 48.5%) and eyes that received intrascleral (Group 2, 85 eyes, 51.5%) MMC. Surgical success was defined as an intraocular pressure (IOP) of 6-21 mmHg with or without topical antiglaucoma medication use. Results: Mean IOP values were not significantly different between Group 1 and Group 2 (P > 0.05) until 2 weeks after surgery, while they differed significantly at 1, 3, 6, 12, and 24 months after surgery (P < 0.05). The mean number of antiglaucoma medications was 3.6 ± 0.6 and 3.5 ± 0.7, respectively, before surgery (P = 0.327) and 0.27 ± 0.32 and 0.10 ± 0.29, respectively, at 24 months after surgery (P = 0.001). The surgical success rate at 24 months was 86.25% and 94.12% in Groups 1 and 2, respectively (P = 0.041; log-rank test). Encysted blebs were observed in 17 and 8 patients in Groups 1 and 2 (P = 0.034), respectively, at 24 months. There was no statistically significant difference in the incidence of hypotony, choroidal detachment, conjunctival leakage, cataract and the rate of postoperative procedures between Groups 1 and 2 (P > 0.05). Conclusions: Compared to the subconjunctival method, the intrascleral method of MMC application can increase the long-term success of trabeculectomy without increasing the complication rate.