needle revision with mitomycin-c in encapsulated blebs

the most common cause of failure during the first trimester after trabeculectomy is encapsulated bleb and needling bleb revision is a less invasive method in the management of refractory cases. the purpose of this study is to determine the efficacy and safety of mitomycin-c (mmc) augmented bleb revision of failed filtration surgery. this study is a before-after (paired) observation. 33 patients with failed trabeculectomy because of bleb encapsulation, whose intraocular pressure (iop) was not reduced under 21 mmhg despite of medications and digital massage , underwent needling bleb revision and subconjunctival injection of 0.1 ml mmc (0.4 mg/ml).the mean follow-up time was 9.24 ± 5.27 months (1-20 months). statistical analysis of the data included the paired two-tailed student's t test for preoperative and postoperative iop and number of medications. 36 needling procedures (mean, 1.09 ± 0.21 revisions per eye) were performed on 33 eyes. patients were between 10-80 years old (mean, 45.67 ± 22.41 years) and mean follow-up was 9.24 ± 5.27 months. iop decreased from 29.06 ± 5.03 mmhg to 18.21 ± 6.76 mmhg at last follow-up ( p= 0.000). antiglaucoma medications decreased from 2.18 ± 0.58 to 1.36 ± 0.29 at last follow-up ( p= 0.000).overall, 6 (18.2%) of 33 cases achieved a complete success and 20 (60.6%) of cases achieved a qualified success. the complications of this procedure were subconjunctival hemorrhage (17 cases), hyphema (5 cases) and conjunctival button hole (2 cases). needling bleb revision with mitomycin-c appears to be an effective and relatively safe way to revive failed filtration surgery.