The Pattern of the Corneal Innervation in Rabbits

Abstract

The corneal nerves were studied in the rabbit by the Gairn AuCl3 staining method, and by a modification of Heller''s methylene blue staining method. There are 20-30 main stem branches which pass into the substantia propria deep to the limbal epithelium. Their myelin sheaths are lost within the first mm. The nerve fibers branch dichotomously and form networks at 3 levels: an intra-epithelial plexus with the boutons lying between or on the epithelial cells but not within the cells, under Bowman''s membrane, and within the substantia propria. There are no anastomoses between the various main stem bundles. The vital staining method reveals 2 distinct types of fiber in the nerve bundles: a fiber with distinct "boutons de passage" and fine linking nerve processes, and a coarse fiber with indistinct boutons de passage. It is suggested that the former fibers may be sensory and the latter autonomic.