The Tissue Changes of Filtering Site Following Glaucoma Filtration Surgery with Various Mitomycin C Concentrations

ABSTRACT

The most common cause of the postoperative failure of glaucoma filtration surgery(GFS) is scarring secondary to fibroblast proliferation and fibrosis at the interface of the episclera and conjunctive. To inhibit this process, mitomycin C(MMC) has been studied experimentally, both in vivo and in vitro. In evaluating the toxicity of MMC, we observed the inhibition of fibroblast proliferation and of fibrosis by light microscope, and the ultrastructual changes of the sclera by transmission electron microscope following the soaking of MMC during GFS in rabbit eyes. The sixty rabbits which comprised this study were divided into four groups; the first control group(I) was soaked with the BSS during GFS, the second(II), the third(III), and the fourth(IV) group were soaked with the 0.2 mg/ml, 0.5 mg/ml, and 0.5 mg/ml MMC soaked groups, respectively, during GFS as experimental groups. On histologic examination, the degree of proliferation of fibroblasts with fibrosis and infiltration of lymphocytes in MMC soaked groups was less than those of BSS soaked group at 2 weeks and 2 months after GFS. At six months after GFS, there was ultrastructural evidence of degenerative changes of scleral fibroblasts such as clumping of nuclear chromatin, wrinkling of nuclear membrane, and cystic dilatation of rough endoplasmic reticulum in MMC soaked groups. Higher concentration of MMC caused more degenerative changes in cellular structures. These results surggested that the scar formation after GFS could be significantly suppressed by a single application of MMC during surgery, and MMC could be0 used effectively in cases of poor prognosis of GFS. Further experiments need to be conducted to determine the optimal concentration, exposure time, and application method of MMC.