Comparing the outcome of delayed postoperative versus intraoperative mitomycin C use in trabeculectomy: A randomized control trial

Purpose To compare the effect of delayed postoperative mitomycin C (MMC) application on surgical outcome and bleb morphology with intra-operative application in trabeculectomy.Method This monocentric, unmasked randomized control trial recruited primary glaucoma patients between 18-70 years of age. They were randomized into Group I (intraoperative MMC group) and Group II (postoperative MMC group). All patients underwent standard fornix-based trabeculectomy with differences only in the MMC application step. In Group I, 0.2 mg/ml MMC was applied intraoperatively for two minutes, while in Group II, 0.01 mg (0.25 ml of 0.04 mg/ml) of MMC was injected 7-14 days postoperatively above the bleb. The primary outcome was surgical success, whereas the secondary outcome measures were rate of complications and bleb morphology. Complete and qualified success was defined as intraocular pressure (IOP) between 6-21 mm Hg without and with <= 2 anti-glaucoma medications (AGMs).Results Fifty-six eyes (31 in Group I and 25 in Group II) were analyzed for the outcome at 18 months follow-up. Surgical success was comparable (70.9% vs 68%) (p = 0.811) between the groups. There were higher incidences of hypotony (41.9% vs 36%) in Group I. Incidences of persistent-hypotony (p = 0.032) and late-hypotony (p = 0.127) were higher in Group I. Two eyes developed hypotony maculopathy in Group I, while none in Group II. The blebs in Group I were more avascular, cystic and developed thinning, while those in Group II were diffuse and shallow.Conclusions Delayed postoperative MMC application may be as effective as standard trabeculectomy with MMC in lowering IOP with a lower rate of complications.