[Retrobulbar neuritis--diagnosis and differential diagnosis]

The American multicenter study 'A randomized, controlled trial of corticosteroids in the treatment of acute optic neuritis' (5) showed how a retrobulbar neuritis should not be treated, Oral steroids (1 mg per kilogram of body weight per day) are not only ineffective but also associated with a higher rate of recurrences compared to high dose i.v. methylprednisolone. In the light of this study, 'low-dose' steroid therapy for retrobulbar neuritis is contraindicated. High-dose methylprednisolone speeds up recovery of the visual function and lowers the recurrence rate two years after treatment; however, this protective effect could not be demonstrated after three years. These recommendations are valid only for primary demyelinating retrobulbar neuritis. Other less common optic neuropathies, such as these of microvascular origin, respond to 'low-dose' steroids; therefore, the diagnosis of primary demyelinating retrobulbar neuritis must be made with caution as a diagnosis of exclusion. This paper discusses a number of important optic neuropathies and gives recommendations for investigations. Compressive optic neuropathies and chiasmal disease will not be covered here.