They are tumors that grow in various parts of the brain, they can affect a) One or both optic nerves b) The optic chiasm. They are rare and their cause is unknown, they are slow growing and noncancerous (benign), and they occur in children, almost always before the age of 20 years. Most cases are diagnosed within 5 years.

Treatment: a) watchful waiting: close monitoring of the patient's condition, without providing treatment, until symptoms appear or change b) surgery c) radiation therapy d) chemotherapy.