the type of visual field loss will depend on which portions of the optic nerve were damaged. in general, the location of the damage in relation to the optic chiasm (see diagram above) will affect the areas of vision loss. damage to the optic nerve that is anterior, or in front of the optic chiasm (toward the face) causes loss of vision in the eye on the same side as the damage. damage at the optic chiasm itself typically causes loss of vision laterally in both visual fields or bitemporal hemianopsia (see image to the right). such damage may occur with large pituitary tumors, such as pituitary adenoma. finally, damage to the optic tract, which is posterior to, or behind the chiasm, causes loss of the entire visual field from the side opposite the damage, e.g. if the left optic tract were cut, there would be a loss of vision from the entire right visual field.