Comparative evaluation of outcomes of novel approach of subconjunctival Mitomycin C (MMC) injection at the end of trabeculectomy versus intraTenon injection of MMC prior to the initial conjunctival incision – A pilot study

PURPOSE: To describe a novel approach of subconjunctival injection of mitomycin C (MMC) at the end of trabeculectomy and compare it with intraTenon MMC injection. METHODS: This pilot study included 40 eyes of 40 patients with uncontrolled primary and secondary glaucoma. Patients below18 years and failed trabeculectomy were excluded. Patients were randomly allocated into groups A and B (20 patients each). Group A patients received subconjunctival MMC injection in the superonasal quadrant at the end of standard trabeculectomy. Group B received an intraTenon MMC injection before the initial conjunctival incision. Outcome measures included intra-ocular pressure (IOP) reduction, bleb morphology, and complication rates. The complete success was defined as an IOP of ≤21 mmHg without antiglaucoma drugs. RESULTS: The mean preoperative IOP of 46.00 ± 11.2 mmHg in group A and 43.05 ± 10.3 mmHg in group B reduced to 12.00 ± 2.41 mmHg (P ≤ 0.001) in group A and 13.65 ± 2.76 mmHg in group B (P ≤ 0.001) at last follow-up. Complete success was 95% and 75% in groups A and B, respectively, 19 months after surgery. Avascular microcystic blebs (70% of group A and 45% of group B) were more common than avascular white blebs (15% in group A and 35% in group B). No intraoperative complications were seen. Postoperative wound leak, hypotony, choroidal detachment, or endophthalmitis were not encountered in any group. CONCLUSION: A novel approach of subconjunctival MMC application during trabeculectomy is reported. Both approaches appear to be highly effective in reducing IOP in primary and secondary glaucoma with similar safety profiles and bleb morphology. Subconjunctival MMC yielded a greater success rate (95%) compared to the intraTenon MMC group (75%).