Pfizer, UK National Institute for Health Research Biomedical Research Centre.

No abstract

Aims: To prospectively study the evolution of possible high risk features of conjunctival filtration blebs like avascularity, transconjunctival oozing (TCO), and leaks after mitomycin C (MMC) enhanced glaucoma surgery. Methods: Single observer, 2 year prospective study on bleb characteristics of 125 eyes of 125 consecutive patients who had MMC augmented glaucoma surgery with initially successful filtration. MMC (0.2 mg/ml for 2 minutes in most cases) was applied on the area of the scleral flap before dissection. Glaucoma surgeries included were trabeculectomy, deep sclerectomy, and combined procedures. A dry fluorescein strip was applied on the avascular part of the bleb and observed for aqueous egress with flow (point leak, PL) or without (TCO). Results: The mean time (95% CI) for observing bleb avascularity, TCO, and bleb leaks were 106 days (69 to 143), 208 days (155 to 261), and 609 days (559 to 659), respectively. Bleb leaks were observed in 17 eyes (13.6%)-15 (24.6%) in the trabeculectomy group and two (3.1%) in the deep sclerectomy group (p = 0.003). Kaplan-Meier survival analyses showed that the probability of observing bleb avascularity at sixth, 12th, and 24th month after surgery was 56%, 71%, and 73%, respectively. In eyes with avascular blebs, the probability of developing TCO and leaks was 77% and 1% at 6 months, 81% and 12% at 12 months, and 95% and 26% at 24 months, respectively. Cox's regression analyses and log rank tests showed that eyes with larger avascular blebs (.4 mm) were more likely to develop TCO (hazard ratio 3.77, p = 0.001) and delayed bleb leaks were more likely to be seen in eyes of the trabeculectomy group rather than the deep sclerectomy group (hazard ratio 0.06, p = 0.0006). Conclusions: MMC application over the area of scleral flap dissection during glaucoma surgery is associated with a high incidence of bleb avascularity, TCO, and delayed bleb leaks. Most eyes developed bleb avascularity within the first year after surgery. TCO will eventually be seen in all eyes with avascular blebs and the incidence of leaks gradually increases with time. This study shows that patients with eyes undergoing glaucoma surgery with MMC and avascular blebs should be monitored indefinitely.

Aims To investigate the comparative efficacy and safety of deep sclerectomy with and without intraoperative mitomycin C (MMC) application for lowering the intraocular pressure (IOP). Methods A total of 71 eyes of 71 consecutive patients who had routine deep sclerectomy (DS), nonaugmented (DS-noMMC) or with mitomycin C (DS-MMC) augmentation (0.2 mg/ml for 2 min) and follow-up of 4 months or more were identified from an ongoing prospective database on glaucoma surgery. Indications for MMC use were the presence of risk factors for subconjunctival scarring and low target IOPs. MMC 0.2 mg/ml was applied in the sub-Tenons space for 2 min. Results There were 19 eyes in the DSnoMMC group and 52 eyes in the DS-MMC group. In 11 eyes (15.5%), the procedure was complicated by intraoperative perforation of the trabeculo-Descemet's window. Eyes in the DS-MMC group had significantly lower IOPs (MANOVA, P ¼ 0.04). Kaplan-Meier survival curve analysis showed that the probability of maintaining IOP below target IOP level, below 18 mmHg and below 14 mmHg at 1 year was 51, 67, and 35% for the DS-noMMC group and 80, 86, and 74% for the DS-MMC group. The survival rates of the DS-MMC group were not statistically significant (P ¼ 0.06) when the success criterion was maintaining an IOP less than 18 mmHg but were significant for the other criteria, namely IOP less than target levels (P ¼ 0.03) and less than 14 mmHg (P ¼ 0.03). Nd:YAG goniopuncture to lower IOP to target levels was done more frequently in the DS-noMMC group (13 eyes, 81%) than the DS-MMC group (20 eyes, 45%) and this difference was significant (P ¼ 0.03). The prevalence of avascular areas within filtration blebs and transconjunctival oozing of aqueous was significantly higher in the DS-MMC group (Po0.01).Conclusions The use of intraoperative MMC during deep sclerectomy has a significant effect on the postoperative IOP and increases the probability of achieving target IOPs. However, our current technique of MMC application is associated with a higher incidence of avascular blebs and transconjunctival oozing.

This study suggests that MMC is more effective than 5-FU for needle revision of failed trabeculectomy blebs.