HISTOCHEMISTRY OF CORNEAL GRANULAR DYSTROPHY

The problem of the nature of the granular deposits in Groenouw's type I corneal dystrophy remains unsolved, largely because of the limited range of amino-acids and protein groups that can be identified by histochemical techniques, and partly because of the difficulties encountered in interpreting the results of electron microscopy. Nevertheless the deposits have been shown to consist principally of a non-collagenous protein containing tyrosine, tryptophan, arginine, and sulphur-containing amino-acids. The possible origin of the abnormal protein is thought to include the epitheliuni and extracorneal sources as well as the keratocyte, although the evidence for each of these suggestions is entirely circumstantial. The implication of the demonstration of amyloid foci in a minority of the cases examined is discussed with regard to the possibility that the lesions of granular dystrophy are in some way related.