Optic nerve glioma is a heterogenous tumor that originates from glial cells in the central nervous system (CNS). Optic nerve gliomas are also referred to as optic gliomas or juvenile pilocytic astrocytomas, as these tumors are primarily seen in children. Of these tumors, 10% originate within the optic nerve, 50% include the optic chiasm, and approximately 5% are multicentric, which includes the hypothalamus.

Optic nerve gliomas are mostly seen in the pediatric population in the first decade of life. Gliomas in general are the most common CNS tumor in pediatric patients, and optic nerve gliomas make up 2%-5% of all gliomas. About 30%-50% of optic nerve gliomas in children are associated with neurofibromatosis type 1 (NF1). Optic nerve gliomas can be rarely found in adults. They almost exclusively present in males with a much more rapid progression and a poor prognosis.

Pediatric patients will present with a slow, progressive visual decline. In children, these tumors are typically slow growing. As the tumor progresses, a unilateral, painless proptosis can be seen, and patients may have total or partial vision loss at that time. Often, an afferent pupillary defect is present.

The most important risk factor for optic nerve gliomas is NF1, which is an autosomal dominant disorder. Approximately 10%-15% of NF1 patients will have optic nerve gliomas. Tumors associated with NF1 generally have the best prognosis. Sporadic tumors are more aggressive and have a higher chance of tumor progression and visual decline.