A Cochrane review [Abstract] 1 included 11 studies with a total of 698 subjects. Three types of participants were enrolled: high risk of failure, trabeculectomy combined with cataract surgery, and no previous surgical intervention. Mitomycin C (MMC) reduced the relative risk of failure of trabeculectomy both in eyes at high risk of failure (RR 0.32, 95% CI 0.20 to 0.53) and those undergoing surgery for the first time (RR 0.29, 95% CI 0.16 to 0.53). No significant effect on failure was noted in the group undergoing trabeculectomy combined with cataract extraction. Mean intraocular pressure was significantly reduced at 12 months in all three participant groups receiving MMC compared to placebo. No significant increase in permanent sight-threatening complications was detected. However, none of the trials were large enough or of sufficient duration to address the long-term risk of bleb infection and endophthalmitis which has been reported in observational studies. Some evidence exists that MMC increases the risk of cataract.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment and blinding) and by indirectness (none of the studies used visual field preservation as on outcome and there is lack of long-term data).
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