TRABECULECTOMY AUGMENTED WITH MITOMYCIN-C APPLICATION UNDER THE SCLERAL FLAP

Aim-The authors investigated the safety and intraocular pressure (IOP) lowering effectiveness of trabeculectomy augmented with mitomycin C a pplication beneath the scleral flap, and assessed the influence of pre operative risk factors on the surgical outcome. Methods-A retrospectiv e study of 72 consecutive high risk eyes undergoing trabeculectomy wit h adjunctive mitomycin C (0.2 mg/ml) applied under the scleral flap fo r 5 minutes was performed. Each eye was ascribed a score based on the number of preoperative risk factors, and categorised into one of three risk factor groups. Success was described as unqualified where IOP wa s less than or equal to 21 mm Hg without medication and qualified wher e antiglaucomatous therapy was required to maintain it at such a level . A life table analysis of IOP control was calculated. Results-The mea n IOP (SD) fell from a preoperative level of 28.4 (6.9) to a level of 16.63 (8.06) mm Hg at the last follow up (paired Student's t test: p< 0.0001). Fifty two eyes (72%) were classed as unqualified successes. T he survival rates did not differ significantly between different risk factor groups (log rank test: chi(2) = 0.967, p>0.1). The incidence of postoperative complications compared favourably with reports of mitom ycin C application between Tenon's capsule and the undissected scleral bed. Conclusion-The results illustrate that mitomycin C applied benea th the scleral flap during trabeculectomy in high risk eyes is associa ted with a success rate comparable to other modes of application. The incidence of potentially serious complications such as conjunctival wo und leak and prolonged hypotony was lower than previously published da ta reporting sub-Tenon's administration of mitomycin C. The number and nature of preoperative risk factors do not appear to influence the su rgical outcome. A possible mechanism of action is proposed.