Efficacy and safety of mitomycin C – augmented revisions of non-functioning filtering blebs after trabeculectomy – 7 year results

Introduction
To determine the efficacy and safety of mitomycin C-augmented revision in eyes after failed primary trabeculectomy failure.

Material and methods
Retrospective review of 40 eyes after a single MMC-augmented revision due to primary trabeculectomy failure. Main outcome measures: intraocular pressure, best corrected visual acuity, number of antiglaucoma medications, complications.

Results
Twelve months after revision the mean intraocular pressure declined from 24.5 ± 6.7 mmHg to 15.4 ± 4.4 mmHg (p<0.05) and remained decreased at 24 months (16.33 ± 4.2 mmHg) and at 84 months (16.75 ± 2.8 mmHg). The therapeutic success, defined as intraocular pressure ≤ 18 mmHg without medication at 12 months after revision, was achieved in seventeen eyes (42.5%). Fourteen eyes (35.0%) achieved qualified success, defined as intraocular pressure ≤ 18 mmHg with antiglaucoma medication, and 9 of 40 eyes (22.5%) were classified as failures. Mean best corrected visual acuity did not change significantly after the surgery (12 month: p = 0.76, 36–48 months: p = 0.25, 72–84 months: p = 0.15). The mean numer of medications was reduced from 1.2 ± 0.8 preoperatively to 0.68 ± 0.8 postoperatively at 12 months, to 0.78 ± 0.49 at 24 months and the drop was statistically significantly. Early complications developed in 7 (17.5%) eyes but they resolved spontaneously.

Conclusions
MMC-augmented revision appears to be a safe and useful tool in reducing intraocular pressure after trabeculectomy failure. This simple-technique procedure is successful in 42.5% of eyes for up to 24–36 months and helps protect the eye from other surgical intervention, more destructive for the conjunctiva.