a) What is optic nerve glioma?
Optic nerve glioma is a slow growing tumour developing within the optic nerve. It is more common under the age of 20. Another name for this tumour is a pilocytic astrocytoma. Patients who get this tumour commonly have an under lying medical condition called neurofibromatosis type 1. This is a genetic condition that makes you more likely to grow tumours along your nerves.
b) What are the symptoms of optic nerve glioma?
Since this tumour is slow growing, it usually causes a gradual decrease in vision in the affected eye. The tumour can push the back of the eye causing the eye to stick out (proptosis- picture above). Rarely, the vision may quickly deteriorate. This may be due to bleeding into the tumour, causing it to squash the nerve or the blood vessels to the eye. Sometimes the tumour can spread backwards into the brain. If this happens then headaches (worse in the morning), nausea and vomiting may occur.
c) Will I need any tests?
If optic nerve glioma is suspected then scanning the orbit and the brain is likely to be required. This may include:
• MRI scan
• CT scan
• US scan
If neurofibromatosis is suspected then genetic testing may be performed. A full body scan may also be useful to look for other tumours else where in the body. If the diagnosis is uncertain we may decide to take biopsy.
d) What is the treatment for optic nerve glioma?
If not causing any problems then treatment may not be required. If, however, the tumour is growing and causing forward displacement of the eye or decreasing the vision, then surgery is recommended. Unfortunately, because the tumour is on the optic nerve, removing this may cause damage to the vision. Radiotherapy and chemotherapy may also be used if the cancer has spread to the brain. Our medical oncology team will guide us on the best treatment for your case.
e) How effective is the treatment?
Treatment is effective in slow growing optic nerve gliomas. These are more common in children. In adults, however, aggressive fast growing optic nerve gliomas are more common and are more likely to spread back into the brain and threaten life. These are more difficult to treat.