optic nerve
Meaning of optic nerve: The optic nerve carries visual signals from the retina to the brain and is itself considered an extension of brain tissue.
Definition of optic nerve
The optic nerve is the nerve that carries visual information gathered by the retina, the light sensitive layer at the back of the eye, to the brain for processing into the images a person perceives. It is formed from the combined fibers of specialized retinal cells and exits the back of the eyeball before traveling toward the brain.
Unlike most other cranial nerves, the optic nerve is technically considered an extension of the brain itself rather than a typical peripheral nerve, since it develops from the same embryonic tissue as the brain and is surrounded by the same protective membranes. The two optic nerves partially cross at a structure called the optic chiasm, allowing visual information from each eye to reach both sides of the brain.
Because the optic nerve carries all visual information leaving the eye, damage anywhere along its length, whether from pressure, inflammation, or reduced blood flow, can affect vision in a pattern that depends on exactly where along the nerve the damage occurs.
Also known as
Used in a sentence
Imaging was obtained to evaluate the optic nerve after the patient reported sudden vision loss.
Good to know
Because the optic nerve is technically brain tissue rather than a standard peripheral nerve, it does not regenerate after injury the way many other nerves in the body can.
Word origin
Where “optic nerve” comes from
Formed from Greek optikos, meaning relating to sight, from ops, meaning eye.