10 Facts About Optic nerve

In neuroanatomy, the optic nerve, known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual information from the retina to the brain.

In humans, the optic nerve is derived from optic stalks during the seventh week of development and is composed of retinal ganglion cell axons and glial cells; it extends from the optic disc to the optic chiasma and continues as the optic tract to the lateral geniculate nucleus, pretectal nuclei, and superior colliculus.

Optic nerve has been classified as the second of twelve paired cranial nerves, but it is technically part of the central nervous system, rather than the peripheral nervous system because it is derived from an out-pouching of the diencephalon during embryonic development.

However, most typically, the optic nerve is grouped with the other eleven cranial nerves and is considered to be part of the peripheral nervous system.

Optic nerve is ensheathed in all three meningeal layers rather than the epineurium, perineurium, and endoneurium found in peripheral nerves.

Optic nerve is composed of retinal ganglion cell axons and glia.

Optic nerve leaves the orbit via the optic canal, running postero-medially towards the optic chiasm, where there is a partial decussation of fibers from the temporal visual fields of both eyes.

Damage to the optic nerve that is anterior, or in front of the optic chiasm causes loss of vision in the eye on the same side as the damage.

Injury to the optic nerve can be the result of congenital or inheritable problems like Leber's hereditary optic neuropathy, glaucoma, trauma, toxicity, inflammation, ischemia, infection, or compression from tumors or aneurysms.

Optic nerve hypoplasia is the underdevelopment of the optic nerve resulting in little to no vision in the affected eye.