Mitomycin-C application before versus after scleral flap dissection in trabeculectomy; A randomized clinical trial

Purpose: To compare trabeculectomy with mitomycin-C (MMC) application before versus after scleral flap dissection in terms of corneal endothelial cell loss and surgical outcomes. Methods: In this double blind clinical trial, patients were randomized to MMC 0.02% application before (group A) or after (group B) scleral flap dissection. The main outcome measure was corneal endothelial cell density; secondary outcome measures included IOP, glaucoma medications, success rates (IOP ≤21 and ≤18 mmHg, defined as criterion 1 and 2, respectively) and complications. Results: Overall, 99 eyes of 99 subjects including 72 male and 27 female subjects were operated and followed for at least 6 months. The study groups were comparable in terms of baseline variables. Outcomes of surgery were similar at six months in terms of IOP (11.8±5.8 vs. 11.7±5.5 mmHg, P=0.88) and number of medications (0.2 ±0.6 vs 0.1±0.4, P=0.45). Overall success was comparable at months 1 and 3, but higher in group B at month 6 (82.0% vs. 63.3%, P=0.036 for criterion 1 and 78.9% vs. 59.2%, P=0.044 for criterion 2). Hypotony was more prevalent in group B (8.0% versus 2.0%) but the difference was not significant (P=0.38). Endothelial cell density loss (2.2±7.3 vs 0.9±6.3%, P=0.567) was comparable between the study groups. Conclusion: Corneal endothelial loss following trabeculectomy was comparable with MMC application before and after scleral flap dissection. The sequences were comparable in terms of postoperative IOP and glaucoma medications. Overall success rate was higher at six months in group B and the rate of hypotony was also higher, although insignificantly.