ULTRASTRUCTURAL FEATURES OF FILTRATION BLEBS WITH DIFFERENT CLINICAL APPEARANCES

The authors studied two functioning filtration blebs to evaluate a pos sible transconjunctival route of aqueous humor flow and describe poten tial differences between thin cystic and thick opaque functioning filt ration blebs, The specimens were prepared for light and electron micro scopy immediately after surgical excision because of filtration bleb d iscomfort. Both blebs had normal collagen in the substantia propria. T he collagen, however, was widely spaced and subepithelial connective t issue loosely arranged. Clear spaces were seen in the superficial subs tantia propria. Epithelial cells were focally acantholytic, separated by clear spaces. Consequently, clinically distinct blebs demonstrated similar histologic and ultrastructural features, The epithelial interc ellular spaces observed in this study provide anatomic evidence that a queous could move transconjunctivally as a mechanism for filtration bl eb function.