Pathology of anterior chamber angle in diabetic neovascular glaucoma: extension of corneal endothelium onto iris surface.

The purpose of this study is to elucidate the extension of the corneal endothelium onto the iris surface, a condition which has been found in the eyes with rubeosis iridis in various ocular disorders. Histopathology of the anterior chamber angle was studied by electron microscopy in 6 eyes with neovascular glaucoma occurring in the advanced stage of diabetic retinopathy. Histopathological findings embraced extensive peripheral anterior synechiae occluding the filtration angle and fibrovascular tissue on the anterior surface of the iris. In addition, formation of a continuous layer of endothelium was observable on the surface of the iris facing the anterior chamber in the 6 eyes. The newly formed endothelium was continuous with the corneal endothelium at the pseudo-angle formed by the attachment of peripheral anterior synechiae. Two types of corneal endothelial cells were found near the pseudoangle, one type with degenerative changes and the other apparently engaged in normal metabolic activity. It may be assumed from these findings that, while the corneal endothelium undergoes degeneration, new cells of unknown origin proliferate on the posterior corneal surface to replace the disrupted corneal endothelium and extend onto the iris surface.