This is formed by a crossing-over of the two optic nerves (see EYE) which run from the back of the eyeballs to meet in the mid line beneath the brain. Nerve ?bres from the nasal part of the retina cross to link up with ?bres from the outer part of the retina of the opposite eye. The linked nerves form two separate optic tracts which travel back to the occipital lobes of the brain.
In?ammation of the optic nerve (see EYE) which may result in sudden loss of part of a person’s vision. It is usually accompanied by pain and tenderness on touch. The cause is uncertain, although in some cases it may be a prcursor of MULTIPLE SCLEROSIS (MS): CORTICOSTEROIDS may help by improving the loss of visual acuity, but seems not to check the long-term in?ammatory activity.... optic neuritis
a rare hereditary disorder, usually affecting young males, that is characterized by loss of central vision due to neuroretinal degeneration. Visual loss in one eye is rapid and usually followed by loss in the second eye. [T. Leber]... leber’s optic atrophy
(optic commissure) the X-shaped structure formed by the two optic nerves, which pass backwards from the eyeballs to meet in the midline beneath the brain, near the pituitary gland (see illustration). Nerve fibres from the nasal side of the retina of each eye cross over to join fibres from the lateral side of the retina of the opposite eye. The optic tracts resulting from the junction pass backwards to the occipital lobes.... optic chiasm