optic

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optic

 [op´tik]
ocular (def. 1).
optic nerve the second cranial nerve; it is purely sensory and is concerned with carrying impulses for the sense of sight (see vision). See anatomic Table of Nerves in the Appendices.

The rods and cones of the retina are connected with the optic nerve which leaves the eye slightly to the nasal side of the center of the retina. The point at which the optic nerve leaves the eye is called the blind spot because there are no rods and cones in this area. The optic nerve passes through the optic foramen of the skull and into the cranial cavity. It then passes backward and undergoes a division; those nerve fibers leading from the nasal side of the retina cross to the opposite side while those from the temporal side continue to the thalamus uncrossed. After synapsing in the thalamus the neurons convey visual impulses to the occipital lobe of the brain.

Degenerative and inflammatory lesions of the optic nerve occur as a result of infections, toxic damage to the nerve, metabolic or nutritional disorders, or trauma. Syphilis is the most frequent cause of infectious disorders of the optic nerve. Methanol (methyl alcohol) is highly toxic to the optic nerve and can cause total blindness. Diabetes mellitus and anemia are examples of metabolic and nutritional disorders that can lead to damage to the optic nerve and produce serious loss of vision.

Treatment of optic neuritis is aimed at control of the primary cause of the disorder. Cortisone and similar steroids are often used to relieve symptoms; however, nothing can be done to regain sight lost through damage to the nerve.

op·tic

, optical (op'tik, op'ti-kăl),
Relating to the eye, vision, or optics.
[G. optikos]

optic

(ŏp′tĭk)
adj.
1. Of or relating to the eye or vision.
2. Of or relating to the science of optics or optical equipment.
n.
1. An eye.
2. Any of the lenses, prisms, or mirrors of an optical instrument.

op·tic

, optical (op'tik, -ti-kăl)
Relating to the eye, vision, or optics.
[G. optikos]

optic

of or relating to the eye or to vision.

optic 

Pertaining to light or to vision.