a) What is optic nerve sheath meningioma?
Wrapped around the optic nerve is a sheath. This is similar to the insulation layer of a wire. Along this sheath, a benign tumour called a meningioma can develop. This more commonly occurs between 30 and 60 years of life. It is 4 times more likely to occur in woman. This tumour can also develop in the protective layer of the brain and the spinal cord. Meningiomas may grow fast or slow.
b) What are the symptoms of optic nerve sheath meningioma?
The faster the tumour is growing then the quicker the symptoms will develop. This may include:
• Poor vision
• Proptosis (eye sticking out)
• Double vision .
c) Will I need any tests?
If meningioma is suspected, scanning of the orbit and the brain is usually carried out. Scans may include:
• MRI scan (picture above)
• CT scan
• US scan
Scans may be repeated at a later date to see if the meningioma is growing. If the diagnosis is uncertain we may decide to take a biopsy.
d) What is the treatment of optic nerve meningioma?
Treatment may not be required if the tumour is slow growing and not causing symptoms. This is more common in middle aged patients. In younger patients, however, the tumour is more likely to be aggressive and fast growing. If this is the case, surgery is required. Unfortunately surgery may damage the nerve and cause poor vision. Sometimes radiotherapy is given after surgery to reduce the risk of it coming back later in life. Unfortunately, radiotherapy may also damage the vision.