Computed tomography of chiasmal optic neuritis.

Three cases of chiasmal optic neuritis are described with bitemporal visual field loss and enlargement of the optic chiasm as demonstrated by computed tomography (CT). Exploratory craniotomies were performed in two of the patients, but no tumor was found. After corticosteroid treatment, all three patients experienced virtually complete restoration of normal vision. Although the CT presentation in these patients was indistinguishable from that of a chiasmal glioma, the clinical presentation of acute visual loss in an older child or adult should suggest chiasmal optic neuritis. A period of observation, with or without a trial of corticosteroids, might permit the latter diagnosis and obviate exploratory craniotomy.