Optic nerve sheath meningiomas (ONSM) are rare, frequently unilateral, benign, slowly growing tumors, arising from the meningo-epithelial cells surrounding the optic nerve intraorbital or intercanalicular. Their localization directly impair vision and indirectly impair aesthetics, making a safe classical surgical intervention very difficult and recommending stereotactic fractionated radiotherapy. Women are more affected, the survival rate is good and imaging can sustain differential diagnosis with optic neuroglioma or orbital schwannoma, lymphoma or pseudo tumor.