Optic nerve sheath meningiomas (ONSMs) represent 1–2% of all meningiomas, 1.7% of all orbital tumors, and about 35% of all intrinsic tumors of the optic nerve^1–3. Thus ONSM represent a rare but nevertheless important entity due to their natural course of slowly progressive and unremitting loss of vision. Classical primary ONSM arise from the meningothelial cap cells of the arachnoid membrane surrounding the intraorbital optic nerve and may extend along the optic canal intracrani-ally. Secondary ONSM extends from the planum sphenoidale, tuberculum sellae or anterior clinical process, into the subdural or subarachnoid spaces surrounding the nerve within the optic canal and, ultimately, within the orbit.^3–8 Most ONSMs are unilateral with 5% manifested bilaterally [2]. ONSM occurs predominantly in middle-aged women or in children. The treatment of ONSM remains controversial, but includes surgery, radiotherapy, and plain observation. Complete surgical excision is thought to result in blindness in almost all cases.⁹ When intracranial extension that threatens the optic chiasm or contralateral optic nerve is present, complete excision of the intracranial part via craniotomy has been described.^2,8,19 Complete neurectomy and tumor resection are also performed in cases of severe unilateral loss of vision accompanied by disfiguring proptosis. As surgical reports revealed a high morbidity in terms of visual loss and recurrences due to incomplete removal, other treatment options were debated.^2,11–14