Compressive and infiltrative optic neuropathies

Abstract

Compressive processes of the optic nerve may occur in the intraorbital region, intracanalicular region, optic chiasm, or optic tracts. Those lesions compressing the orbital optic nerve include optic nerve sheath meningiomas, thyroid-associated orbitopathy, and idiopathic orbital inflammatory pseudotumor. Suprasellar tumors, such as pituitary adenomas and craniopharyngiomas, can affect the optic chiasm. Internal carotid, carotid-ophthalmic, and anterior communicating artery aneurysms can compress the intracranial portion of the optic nerve. Sphenoid sinus mucoceles may expand to displace one or both optic nerves or the optic chiasm. Craniofacial fibrous dysplasia involving the sphenoid bone can also cause a compressive optic neuropathy. Primary tumors infiltrating the optic nerve include optic gliomas associated with neurofibromatosis type I, malignant anterior visual pathway gliomas, and gangliogliomas. Lymphomas, leukemias, and leptomeningeal metastases are considered secondary tumors infiltrating the optic nerves. Other etiologies of infiltrative optic neuropathies are inflammatory, such as in sarcoidosis, and infectious, such as in tuberculosis, cryptococcosis, and toxoplasmosis.