What it means
A bundle of over a million nerve fibers that leaves the back of each eye (from the retina) and travels to the brain. It is cranial nerve II. Damage to it causes vision loss that usually cannot be reversed, as in glaucomaglaw-KOH-muhAn eye disease in which the optic nerve is damaged, usually with raised pressure inside the eye, leading to loss of vision.Full entry , where high pressure in the eye harms it over time. Swelling where it enters the eye (papilledema) can be seen with an ophthalmoscope when pressure inside the skull is high.
For the nurse
The optic nerve is checked with tests of visual acuity and visual fields.
At a glance
| Abbreviations | CN II (cranial nerve II) |
|---|---|
| Spanish | nervio óptico |
| Also written | optic nerves |
Related terms
glaucoma
An eye disease in which the optic nerve is damaged, usually with raised pressure inside the eye, leading to loss of vision.
pupil
The round black opening in the center of the colored part of the eye, which lets light in.
visual acuity
How clearly and sharply a person can see.
cornea
The clear, dome-shaped layer at the front of the eye, over the iris and pupil.