TRANSCONJUNCTIVAL MITOMYCIN-C AS AN ADJUNCT TO CONVENTIONAL GLAUCOMA FILTRATION SURGERY IN RABBITS

Purpose: Subconjunctival mitomycin C has been used in glaucoma filtrat ion surgery with success. A prospective, randomized, masked, placebo-c ontrolled study was performed to evaluate whether single transconjunct ival mitomycin C applied either preoperatively or postoperatively woul d enhance the success of filtration surgery in rabbits. Methods: Two g roups of 5 rabbits were studied. In Group I, a Weck-Cel sponge soaked in 0.5 mg/ml mitomycin C was applied transconjunctively for 7 minutes immediately before a full thickness filtering procedure. The other eye was treated similarly with a sponge soaked in balanced salt solution. Group II first underwent filtration surgery followed by treatment wit h either mitomycin-c or balanced salt solution 3 days later. Postopera tive intraocular pressure, bleb status, and complications were evaluat ed. Treatment failure was defined as postoperative pressure within 4 m mHg of that determined preoperatively or the absence of bleb formation . Results: In Group I, mean time to failure (+/- SD) was significantly longer (p = 0.03) in experimental eyes (30 +/- 15.1 days) than contro l eyes (8.6 +/- 0.8 days). In Group II, the time to failure was 12.4 ( +/- 2.6) days versus 9.6 (+/- 2.5) days in the experimental and contro l eyes respectively, but this was not statistically significant (p = 0 .10). Transient limbal vascularization and corneal haze were seen in a ll experimental eyes. Serious complications included late bleb rupture in eyes pretreated with mitomycin C (all eyes in Group I) and corneal decompensation (one mitomycin-c eye). Conclusions: This study demonst rates that a single preoperative tranconjunctival application of mitom ycin-c is more effective at the time of surgery than an application ap plied in the intermediate postoperative period. Additional studies are needed, however, to further refine both the dose and timing of mitomy cin-c application during filtration surgery.