Optic nerve fibres once cut, do not regenerate because they are not covered by

Optic nerve It is a continuation of the nerve fibre layer of the retina, which consists of the axons originating from the ganglion cells. It also contains the afferent fibres of the pupillary light reflex. Morphologically and embryologically, the optic nerve is comparable to a sensory tract. Unlike peripheral nerves it is not covered by neurilemma (so it does not regenerate when cut). Reference :- A K KHURANA; pg num:-287