Radiation-Induced Optic Neuropathy

Optic neuropathy resulting in permanent visual loss is an infrequent delayed complication of radiation therapy. Misdiagnosis of such a lesion may be due to the aspecifical clinical course, the usual tardive appearance and to a possible role of the initial pathology in visual pathways impairment. A radiation optic neuropathy must be suspected when visual disturbances appear in patients submitted to radiotherapy for sellar or skull base pathologies. Contrast-enhanced MR is the examination of choice because it will delineate the radiation-induced lesion and rule out compression of the optic nerves or optic chiasm by the tumoral pathology. The radionecrotic lesion at MR is characterized by segmental swelling with gadolinium enhancement of the visual pathways. Two patients with rapid visual loss about one year after radiotherapy are described. Corticoids and hyperbaric oxygen therapy may be useful in the treatment. The severity of this complication focuses on a strict use of radiotherapy for benign lesions of the sellar and parasellar region.