Endothelial degeneration and posterior collagenous proliferation in aphakic bullous keratopathy.

In series of 39 corneal grafts, aphakic bullous keratopathy comprised 13 (33%) of the cases. By scanning and transmission electron microscopy, endothelial degeneration and posterior collagenous proliferation were consistent features. In all 13 cases, the patchy loss of endothelial cells occurred diffusely over the entire posterior corneal surface. The remaining endothelial cells had become extremely attenuated to increase their surface area. In nine cases, acellular proliferations of collagenous tissue were interposed between the endothelial cells and Descemet's membrane. These posterior collagenous layers were composed of collagen fibrils and basement membrane material, randomly arrayed in a feltwork of uniform thickness; they appeared ultrastructurally identical to those encountered in a variety of conditions involving endothelial distress.