CLINICAL AND HISTOPATHOLOGIC OBSERVATIONS CONCERNING HYPOTONY AFTER TRABECULECTOMY WITH ADJUNCTIVE MITOMYCIN-C

Prolonged hypotony-induced maculopathy is a serious complication of tr abeculectomy with adjunctive mitomycin C. We performed trabeculectomie s with intraoperative mitomycin C on 59 eyes of 52 consecutive patient s. Exposure time to mitomycin C was five minutes in the first seven pa tients, two of whom had prolonged hypotony-induced maculopathy. One of these required surgical revision of the filtering procedure. Light an d electron microscopic study of the excised, avascular bleb disclosed an irregular epithelium and largely acellular subepithelium of loosely arranged connective tissue. Is the remaining 52 eyes, the exposure ti me to mitomycin C was titrated between two and five minutes according to each patient's risk for failure of filtration from. excessive fibro sis. Four additional cases of prolonged hypotony-induced maculopathy o ccurred among these 52 cases (7.7%), all of which were in the lower ri sk groups that received two- or three-minute exposure to mitomycin C. Four procedures failed, requiring further glaucoma surgery, and all of the patients were in the higher risk groups, receiving three- to five -minute exposures. Our titration of the exposure time to mitomycin C m ay have reduced, but did not eliminate, the risk of prolonged hypotony -induced maculopathy, and further study is needed to establish the opt imum protocol for the use of this drug as an adjunct to trabeculectomy .