Comparison of Surgical Outcomes of Sponge Application versus Subconjunctival Injection of Mitomycin-C during Combined Phacoemulsification and Trabeculectomy Surgery in Asian Eyes

Purpose: To compare the outcomes of combined phacoemulsification-trabeculectomy surgery with intraoperative sponge-applied versus subconjunctival injection of mitomycin-C (MMC) in Asian eyes. Methods: This was a retrospective review of 95 eyes that consecutively underwent combined phacoemulsification-trabeculectomy surgery in a tertiary eye center in Singapore from January 2013 to June 2014. Data collected included intraocular pressure (IOP), best corrected visual acuity, and number of glaucoma medications. Outcome measures included postoperative IOP and complications at various timepoints up to 12 months after surgery. Results: Twenty eyes ( 21.1%) received 0.2 mg/ml subconjunctival MMC injection ("Group 1") and 75 (78.9%) received 0.4 mg/ml sponge-applied MMC ("Group 2"). There was no difference between groups in demographics, IOP, and number of glaucoma medications preoperatively. There was a reduction in IOP at postoperative month (POM) 1, 6, and 12 in both the groups (POM12: Group 1, -2.8 +/- 5.36 mmHg, P < 0.001; Group 2, -5.8 +/- 6.29 mmHg, P = 0.054). At POM1, Group 2 showed a trend toward greater IOP reduction (-5.89 +/- 7.67 mmHg vs. -1.55 +/- 5.68 mmHg, P = 0.061). However, at both POM6 and POM12, there was no statistically significant difference in IOP reduction between the two groups. At POM12, complete success, defined as achieving an IOP of between 6 and 15 mmHg without the use of antiglaucoma medications, was achieved in 11 (55%) eyes in Group 1 and 48 (64%) in Group 2 (P = 0.9). There was a lower rate of postoperative hypotony in the Group 1 (0%) compared to Group 2 (8%) (P = 0.34). Conclusion: Combined phacoemulsification-trabeculectomy with subconjunctival MMC injection has comparable outcomes to that with sponge-applied MMC, with a similar reduction in IOP at 1, 6, and 12 months postoperatively and a lower postoperative complication rate.