The optic tract is an extension of the optic nerve located in the brain. It begins at the area where information from the left eye and right eye cross (or “decussate”) to create a complete visual picture.

The optic tract is actually comprised of two separate tracts: the left optic tract and the right optic tract. The left optic tract transfers information from temporal retinal fibers from the left eye and nasal retinal fiber from the right eye. The right optic tract transfers information from the temporal retinal fibers from the right eye and nasal retinal fibers from the left eye.

Damage to the optic tract can lead to homonymous hemianopsia, a condition that causes a partial loss of sight involving either the right or left visual field. Stroke, congenital defects, tumors, infection, and surgery are all possible causes of homonymous hemianopsia. The damaged portion of the optic tract may heal; however, if full sight isn't restored in 6 to 12 months, the condition is likely to be permanent.

Peripheral prism expanders and vision restitution therapy may help a patient to cope with the damage to the optic tract. Peripheral prism expanders are special structures added to glasses that can help a person see more in their periphery, or the area in their field of vision that is farthest to the right and left. Vision restitution therapy is a specific class of eye exercises (or “eye stimulation”) designed to reactivate damaged nerve cells.