Walsh & Hoyt: Etiologies of the Optic Chiasmal Syndrome

Damage to the optic chiasm can occur from the direct or indirect effects of a variety of lesions. Bitemporal field defects are usually caused by damage to the optic chiasm from a cerebral mass lesion. In Rosens series, for example, tumors accounted for 80% of the cases of bitemporal field defects. The most common causes of an optic chiasmal syndrome are pituitary adenomas, suprasellar meningiomas, craniopharyngiomas, gliomas, and aneurysms originating from the internal carotid artery. Chiasmitis, particularly related to multiple sclerosis, sarcoidosis, or systemic lupus erythematosus, is not uncommon. Other unusual causes of an optic chiasmal syndrome are listed.