Optic nerve is -
each optic nerve stas from optic disc and extends up to optic chiasma where the two nerves meet. It is the backward continuation of the nerve fibre layer of retina , which consists of the axons originating from the ganglion cells ie second order neuron. Reference: textbook of comprehensive Opthalmology by AK Khurana.
Second order neuron
First order neuron
Fouh order neuron
Third order neuron
Neuro-ophthalmology