Bleb dystrophy of the cornea: histochemistry and ultrastructure.

Corneal epithelial biopsies from two patients affected with asymptomatic bleb dystrophy were examined by light and electron microscopy. The basis of this disorder appears to be the deposition of a neutral mucopolysaccharide-protein complex as a continuous layer between the basement membrane and Bowman's layer. This material, although homogeneous in light microscopy, has a fine granular ultrastructure. It is friable, and in view of the apparent integrity of the basement membrane/hemidesmosome system it is suggested that the recurrent epithelial erosions which can occur in this disorder result from shearing of this layer. Fissures in the bleb material contain cells which may play a role in its degradation.