Relationship between the Ganglion Cell Layer of the Retina and the Optic Nerve in the Rat

EXPERIMENTAL studies of the changes which take place in the retina when the optic nerve is divided have not yielded consistent results. Birch-Hirschfeld (1900) was the first to report that chromatolysis occurs in the ganglion cells, and a number of authors have described subsequent degenerative changes in the optic nerve fibres themselves. Secondary degeneration of the axons is said to be restricted to the distal segment, the retrograde changes in the axons of the proximal segment being confined to the traumatic phase (Ramon y Cajal, 1928). According to Tello (1907), such degeneration may involve the intraretinal fibres if the nerve is cut close to the eyeball, and is usually followed by regenerative changes. James (1933), who investigated the progress of retrograde degeneration in the rabbit retina, confirmed that chromatolysis occurs soon after the optic nerve is cut, but found that this is succeeded by complete dissolution of most of the ganglion cells. On the other hand, Leinfelder (1938) showed that the degeneration which succeeded optic nerve section in the cat was incomplete,