The optic nerve connects the brain to the eye.
To biologists, the optic chiasm is thought to be a turning point in evolution.
The fibers from the other half of the retina travel to the same side of the brain.

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Diseases of the Optic Chiasm
There are a number of disorders that can affect the optic chiasm.
it sits right under the optic chiasm.
Although small, the pituitary controls the secretion of many different types of hormones.
It helps maintain growth and development and regulates many different glands, organs, and hormones.
Changes in hormones can cause significant changes in our bodies.
People that suffer from a one-sided defect sometimes do not notice it until one eye is covered.
Larsson M.The optic chiasm: a turning point in the evolution of eye/hand coordination.
2013;10(1):41. doi:10.1186/1742-9994-10-41
Gala F.Magnetic resonance imaging of optic nerve.
Indian J Radiol Imaging.
2016;9:291-293. doi:10.2147/IMCRJ.S113339
U.S. National Library of Medicine.Pituitary tumor.