The Comparison of Success Rate by Timing of Subconjunctival Injection of Mitomycin C in Glaucoma Filtering Surgery

ABSTRACT

We conducted a retrospective study to compare surgical outcome and postoperative complications based on the time of subconjunctival injection of mitomycin C (MMC)in glaucoma filtering surgery. 10 eyes of 10 patients with glaucoma was injected subconjunctivally with 0.1 ml of 0.02 mg/ml MMC 12 hours before surgery (preoperative group).13 eyes of 12 patients was injected subconjunctivally with 0.1 ml of 0.02 mg/ml MMC just before making the conjunctival incision and waited 2 minutes before performing trabeculectomy (intraoperative group). Postoperative mean follow-up period were 15.3 months in preoperative group, and 14.2 months in intraoperative group. Preoperative mean IOPs were 25.9 +/-10.9 mmHg in preoperative group, and 37.5 +/-13.1 mmHg in intraoperative group.Postoperative mean IOP in 1, 3, 6, 12 months were 8.4 +/-6.8, 10.1 +/-5.1, 10.4 +/-4.9, 11 +/-3.7 mmHg in preoperative group, and 11.4 +/-7.8, 12.1 +/-8.2, 15.5 +/-5.2, 12.1 +/-7.0 mmHg in intraoperative group.There were statistically significant decreases of IOPs in both groups during follow-up period. We defined surgical success as following1)IOP below 21 mmHg without any antiglaucomatous therapies ;2)postoperative intraocular pressure reduction exceeding 30%of preoperative intraocular pressure. The success rate by Kaplan-Meier method showed no statistical significance between two groups in each definition (p>0.05, log rank test). In conclusion, there was no difference in success rate between two groups. This result suggests that the antiproliferative effect of MMC persists at least 12 hours after subconjunctival injection and the preoperative subconjuctival injection can be more quantitative application method.Futher studies should be done to reduce avascular filtering bleb related complications.