Deep sclerectomy versus trabeculectomy with low-dosage mitomycin C: four-year follow-up

To compare the long-term effects of low-dosage mitomycin C (MMC) in both deep sclerectomy (DSMMC) and trabeculectomy (TPMMC) on intraocular pressure (IOP).

Analysis of extended follow-up of data from a prospective clinical trial. Forty patients were originally randomised to undergo either DSMMC (19 eyes) or TPMMC (21 eyes). Follow-up was performed at postoperative day 1, weeks 1, 2 and 3, as well as months 1, 3, 6, 9, 12, 18, 24, 36 and 48. Two- to three-week data were not included in the statistical analysis. Postoperative complications, number of antiglaucoma medications and IOP were recorded at each visit. Complete (no medications) and qualified (with or without medications) successes were assessed at 2 target IOPs (< or =21 and < or =17 mm Hg) and evaluated by Kaplan-Meier curves.

At 48 months, the mean IOP (+/- SD) was 17.6 +/- 3.4 and 17.8 +/- 3.6 mm Hg in the DSMMC and TPMMC eyes, respectively, a significant reduction from preoperative IOP in each group (p < 0.0005). Complete success was achieved at the < or =21 mm Hg target IOP in 10 (52.6%) and 14 (66.6%) eyes and qualified success in 15 (78.9%) and 18 (85.7%) eyes in the DSMMC and TPMMC groups, respectively. There were no differences in the Kaplan-Meier curves. Hypotony and shallow anterior chamber were significantly more frequent in the TPMMC group.

Either procedure controlled IOP efficaciously at our endpoint. Low-dosage MMC can be considered a mild enhancement of deep sclerectomy IOP-lowering effect.