An optic nerve glioma is a tumor that appears on the structure that carries visual input from the eye to the brain. Most gliomas, especially those found in young children, are benign and easily treated. Some tumors in adults, however, quickly turn cancerous, grow aggressively, and spread to other parts of the brain and body. Both forms of optic nerve glioma can result in partial or total vision loss, as well as headaches and eye twitching. Small and benign tumors can often be removed surgically, though a cancerous mass may need to be treated with a combination of chemotherapy and radiation.
Doctors do not fully understand why optic nerve gliomas appear. Some studies suggest that genetics play a role in their development, as many patients have familial histories of nerve tissue tumors. Most benign tumors grow very slowly and may not cause any physical symptoms for several months or years. It is possible for a child to have gliomas on each eye, though most patients have singular problems. Malignant growths tend to develop quickly, becoming cancerous and beginning to spread within months of their inception.
An individual who suffers from an optic nerve glioma is likely to experience some degree of vision impairment. Peripheral vision loss is most common, but an advanced glioma can affect all aspects of sight. Depending on how much pressure the tumor places on the optic nerve, the affected eye may bulge outward or twitch uncontrollably. Some patients experience generalized symptoms of fatigue, headache, nausea, and cognitive impairment.
When a primary care physician suspects an optic nerve glioma, he or she usually refers the patient to a neurologist to obtain an official diagnosis. The neurologist can perform computerized tomography (CT) scans and magnetic resonance imaging (MRI) tests on the eyes and brain, looking for signs of unusual masses and scarring. Once a tumor is discovered, the doctor may choose to extract a small sample of tissue for laboratory analysis. Tests can reveal whether the mass is cancerous, benign, or a sign of another more serious brain disease.
After making a diagnosis, the neurologist can determine the best course of treatment. Surgery can usually be performed on a small optic nerve glioma to excise the mass and relieve pressure on the nerve. If surgery is unsuccessful or cancer has already started to spread, a patient may need to undergo several rounds of radiation or chemotherapy. Patients are typically prescribed pain medications and instructed to rest their eyes as much as possible during recovery. Treatment for benign tumors often leads to complete recovery of vision, though malignant problems are likely to result in some permanent vision loss.