Patient and method Despite a high-dose corticosteroid therapy in suspected optic neuritis a 25-year-old woman developed unilateral amaurosis. When visual acuity continuously decreased in the second eye a computerized tomography was performed, which suggested a tumor of the optic nerve. A biopsy of this lesion lead to the diagnosis of Boeck's disease. A long-term corticosteroid therapy was initiated. Over the following 9-year period corticosteroids were dosed according to the results of regular clinical and perimetrical examinations (200 examinations with Octopus-Perimeter 201, program G1). In case of deterioration of the visual field higher oral doses were applied. When no improvement was achieved by this, corticosteroids were given intrathecally. Under this therapeutic regime no systemic side effects were seen.