Walsh & Hoyt: Visual Field Defects

Although there are many variations in the visual field defects caused by damage to the optic chiasm, the essential feature is some type of bitemporal defect, the hallmark of damage to fibers that cross within the chiasm. The bitemporal defects may be superior, inferior, or complete, as well as peripheral, central, or both. Bitemporal field defects are also called heteronymous field defects, a term that distinguishes them from homonymous field defects. Lesions that damage the distal portion of one optic nerve at the anterior angle of the optic chiasm. Lesions that damage the body of the optic chiasm. Lesions that damage the posterior angle of the optic chiasm. Lesions that damage the lateral aspects of the optic chiasm. Visual field defects caused by lesions that damage the optic chiasm after initially damaging the optic nerve or optic tract.