Optic Nerve Glioma

**What is Optic Glioma?**
Optic gliomas affect the optic nerve of the eye. These tumors are created by the development of abnormal cells. The optic nerves function is to carry visual information from the brain to the eye. These tumors also affect the optic chiasm. This is the area where the optic nerve from each eye crosses over each other just anterior to the hypothalamus. Optic Gliomas are very rare and the cause of them is unknown. These tumors are benign and slow growing. They generally affect children before the age of 20. Many believe that the optic glioma is associated with neurofibromatosis Type 1 (NF1). NF1 is characterized by the growth of tumors along nerves in the brain, skin, and other parts of the body.

**Symptoms**
Patients can have vision loss in one or both of their eyes that can lead to blindness. Some patients may also have a decrease in peripheral vision. Other symptoms that may occur are squinting, bulging of one or both of the eyes, and involuntary movement of the eyeball. Some patients may also have delayed growth, loss of appetite, and a malfunction in melatonin.

**Treatments**
Treatment varies with the size of the tumor. The goal of treatment is to cure the disorder, relieve symptoms, and improve vision. Surgical removal may cure optic gliomas. Partial removal of the tumor occurs in many cases to minimize pressure on the brain from the tumor. Another form of treatment is radiation therapy. The newest technique to remove this tumor creates a 3D image of the brain and glioma and then irradiates the tumor in a number of different directions. Head CT scans and head MRI scans are used to confirm the diagnosis and location of the tumor.

**Prognosis**
The outlook is unpredictable. Early diagnosis and treatment increases the chance of a positive outcome. Majority of the time surgery cures the symptoms, while in some patients the tumor will return. This condition tends to be stable for along period of time since the tumor is very slow growing. Tumors may behave aggressively though depending on what area of the brain it affects.

Magnetic resonance image of a large retrobulbar optic nerve tumor

This child developed visual difficulties and was discovered to have a glioma (nerve tumor) in the optic nerve. The tumor has enlarged the bony opening (optic foramen), through which the optic nerve passes. This can be seen on the right side of picture.