Endothelial decompensation following cataract extraction with or without placement of an IOL, may lead to corneal edema(#21970) causing severe visual loss and irregular astigmatism.  Bullae may form between the corneal epithelium and underlying Bowman's layer due to degeneration of the epithelial basement membrane with loss of hemidesmosomes secondary to edema of the basilar cell layer (#21971).  In late stages, the bullous cavity is replaced by an organized fibrous tissue ("placque") interposed between the epithelium and Bowman's layer.  The endothelial cell layer is characteristically absent or markedly attenuated(#21973).