Pathognomonic for primary optic nerve meningioma (intraorbital, intracanalicular or intracranial) is the diagnostic triad of progressive deterioration of vision (often over a period of years), primary optic atrophy and optociliary shunts ( Hoyt -Spencer sign) in a patient (frequently women) over 20 years of age. Above all at the beginning, the suspected diagnosis is retrobulbar neuritis. The correct diagnosis is made by computer tomography (enhancement with contrast, coronal sections). The author discusses whether surgical treatment ( orbitotomy or craniotomy) is to be preferred to conservative radiation therapy.