THE EFFECT OF REDUCING THE EXPOSURE TIME OF MITOMYCIN-C IN GLAUCOMA FILTERING SURGERY

Background: The use of adjunctive intraoperative mitomycin C has consi derably improved the success rate of glaucoma filtering surgery. Howev er, the ideal concentration and exposure time of mitomycin C is unknow n. The purpose of this study is to determine whether a satisfactory su rgical outcome can be achieved with a tower incidence of adverse side effects by using a shorter exposure time of mitomycin C than has been recommended previously. Methods: Twenty-five eyes of 25 consecutive pa tients who were considered to be at high risk for surgical failure bec ause of their age (<55 years), previous failure of trabeculectomy, pre vious cataract surgery, or traumatic glaucoma received a single intrao perative application of mitomycin C (0.2 mg/ml for 2 minutes). They we re case-matched with a group of 48 consecutive patients who received a single intraoperative application of mitomycin C (0.2 mg/ml for 5 min utes) by using age, race, type of refractory glaucoma, and preoperativ e intraocular pressure (IOP) as variables. Results: Eighteen months af ter surgery, 22 (88%) patients in the 2-minute group and 21 (84%) pati ents in the 5-minute group had an IOP less than 21 mmHg with or withou t treatment. No significant differences were found in the complication rate: in 2 (8%) of 25 eyes of the 2-minute group, chronic hypotony de veloped compared with 3 (12%) of 25 eyes in the 5-minute group. Hypoto ny-related maculopathy developed in one eye in the 5-minute group. A c ystic bleb was found in 15 (60%) eyes in the 2-minute group compared w ith 19 (76%) eyes in the 5-minute group, although this difference was not statistically significant. Two (8%) eyes in the 2-minute group and one eye (4%) in the 5-minute group had a bleb-related infection. In o ne (4%) patient in each group, late severe endophthalmitis developed. Conclusion: These results suggest that a 2-minute intraoperative appli cation of 0.2 mg/ml mitomycin C is as effective as a 5-minute exposure , but the complication rate remains unaltered.