Purpose: To evaluate the short-term efficacy and safety of needle revision of failed filtering blebs augmented with subconjunctival injection of MMC.
Methods: 41 consecutive cases with an indication for repeated filtration surgery underwent needle revision of their failed bleb under topical anesthesia. Reformation of the bleb was achieved by insertion of the needle under the scleral flap, via the sclerostomy, into the anterior chamber. A 0.1 cc of 0.1 or 0.2 mg/ml MMC solution was then injected with another syringe under the bleb with the bevel of the needle facing away of the sclerostomy.
Results: Six months after the procedure intraocular pressure decreased from a mean of 26.4 ± 6.2 to 16.4 ± 6.5 (p = 0.000) and the number of medications from 2.8 ± 1.4 to 0.6 ± 1.1 (p = 0.000). The overall success rate (5<IOP<22 and no serious complications) was 76%. The initial IOP, the number of previous surgical procedures, the glaucoma type and the lens status did not influence the success rate. The extent of the resulting filtering bleb was statistically significantly larger in the successful cases (2.0 ± 0.8 vs. 0.33 ± 0.5, p = 0.000). The mean visual acuity remained stable in the other 40 cases.
Conclusions: This miniature surgical procedure may be considered as an alternative to other more complicated procedures in cases of failed filtering blebs. Bleb formation was essential for successful reduction of IOP. Therefore, subconjunctival injection of MMC by itself may not lower the IOP in humans.