Clinicopathologic features of excised mitomycin filtering blebs
A. K. Hutchinson, H. E. Grossniklaus, R. H. Brown, P. E. McManus and C. K. Bradley
Department of Ophthalmology, Emory University School of Medicine, Atlanta, Ga.
Using light and electron microscopy, we examined two conjunctival filtering
blebs that had been treated with mitomycin just prior to trabeculectomy and
were later excised due to ocular hypotony. Light microscopy showed
attenuated epithelium, loosely arranged subepithelial connective tissue,
and scattered acute and chronic inflammatory cells. Electron microscopy
also showed these findings and demonstrated the presence of presumably
viable activated fibrocytes in the subepithelial connective tissue. The
presence of inflammatory cells in the blebs was attributed to concurrent
infections and suggests that mitomycin does not completely suppress, but
may attenuate, the inflammatory response. The mechanism of hypotony and
bleb failure in the two eyes was most likely a combination of
over-filtration and a persistent wound leak due to a lack of postoperative
subconjunctival fibrosis secondary to treatment with mitomycin.
