Detection of inflammatory lesions of the optic nerve by magnetic resonance imaging requires a special imaging technique. In 3 patients with persisting visual loss due to retrobulbar neuritis we scanned the optic nerve with a short inversion recovery sequence. In each of the 3 patients magnetic resonance imaging revealed inflammatory lesions in the intracanalicular portion of the optic nerve. It is supposed that the unfavorable location of the lesions in the optic canal is responsible for the poor recovery of visual acuity. In another patient with a bilateral optic nerve atrophy demyelination of the optic nerve could be made visible.