May also be called: Optic Glioma; Optic Pathway Glioma; Juvenile Pilocytic Astrocytoma

An optic nerve glioma (glee-OH-muh) is a type of brain tumor that forms in or around the optic nerve, which connects the eye to the brain.

More to Know

The brain and central nervous system are made up of nerve cells and glial cells. Glial cells support and protect the nerve cells. When a glial cell has a defect and grows out of control, the tumor that forms is called a glioma.

Optic nerve gliomas form along the pathway of the optic nerve, which sends signals to the brain about what the eye sees. Optic nerve gliomas mostly affect kids under age 10 and those with the genetic condition neurofibromatosis type 1 (which causes tumors to grow on nerve tissue). The most typical symptom is progressive vision loss because of the tumor pressing on the optic nerve. With slow-growing tumors, this may be hard to spot at first — especially in younger children who can't describe what they're seeing.

Kids also may start tilting their heads or experiencing what seem like developmental delays, such as clumsiness during walking, speech problems, or behavior changes. A condition called nystagmus (when the eyeballs appear to "jitter" by themselves) also might appear. Sometimes, growth problems can happen if the tumor is pressing on the pituitary gland.

Doctors diagnose optic nerve gliomas with imaging tests such as MRI (magnetic resonance imaging) or CT scans and vision testing. Children who have these tumors are watched closely to see if the tumor gets worse or improves on its own. Treatment usually involves chemotherapy, and radiation also can be used. Surgery usually isn't done with this type of tumor.

Keep in Mind

Although optic nerve gliomas are serious tumors, they usually grow slowly, have a high cure rate, and rarely cause blindness. Most kids do well with treatment, and further vision loss usually is prevented.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.