What Is Optic Glioma?

Medically Reviewed by Melinda Ratini, MS, DO on July 23, 2023
4 min read

Optic glioma is a brain tumor that grows slowly. Around 75% of diagnoses occur in children younger than 10 years old. Optic glioma accounts for approximately 5% of all childhood brain tumors. The tumor can impact your health and body function in many ways as it gets larger.

Optic glioma is also referred to as an optic pathway glioma. Optic gliomas stem from glial cells in your brain that function to support and nourish your brain’s neurons. They grow near your eye’s optic nerve, the nerve that connects your eye to your brain.

An optic glioma may press into your eye as it grows, making your vision blurry and potentially leading to blindness. Because it grows so slowly, the vision changes may not be obvious at first. It may impact one or both eyes. The good news is that while they are very serious, optic gliomas are also easily cured in most cases.

These brain tumors are serious because of the location of the optic system. Your optic nerve meets your brain near the hormone center. As a tumor grows, it may also impact your endocrine functions, including the production of appropriate hormones, the balance of salt and water in your body, appetite management, and sleep.

Your brain has a blood barrier that prevents infection from reaching your brain. This barrier also keeps tumors contained within your brain most of the time, so they don’t spread to the rest of your body. However, less than 5% of the time, an optic glioma moves beyond your brain and spine to affect other parts of your body.

Brain tumors like optic glioma may cause a range of symptoms depending on the areas of the brain they impact. In the case of an optic glioma, vision problems may be attributed to other health conditions or concerns. Aside from vision problems, common symptoms include:

  • The eyeball sticking out further than it should from the socket
  • Hormone problems like abnormal growth, gaining or losing weight without explanation, or early puberty 
  • Endocrine malfunction like needing to urinate more often than normal

If your child is diagnosed with neurofibromatosis 1 (NF1), they are more likely to suffer from an optic pathway glioma. This type of tumor affects around 15% of children with the disease. However, most of the time, this type of optic glioma stops growing and dissipates on its own at some point without the need for intervention.

When your doctor diagnoses an optic glioma, they also give it a grade based on severity. Low-grade optic gliomas are categorized as a one or two in severity. These account for two-thirds of all childhood optic gliomas. More serious tumors are categorized as a three or four. These grades are given after looking at a tissue sample from the tumor under a microscope.

Your doctor may use both vision and imaging tests to look for the presence of an optic glioma. These tests include:

  • A complete physical exam to assess overall health
  • A CT scan to provide detailed imaging of your brain and optic nerves
  • Vision tests to assess eyesight‌
  • An MRI scan is similar to a CT scan, although it uses a combination of magnets and radio frequencies to produce images‌

Various medical experts may be involved in different stages of testing. Once they each produce results, they compare notes, come to a conclusion, and then share their comprehensive findings with you. If you do have an optic glioma, the next step is to choose the best treatment option based on your overall health and the severity of the condition.

Factors that impact treatment options include:

  • Age, overall health, and medical history
  • The type of tumor, its location, and its size
  • Progression of the disease
  • Tolerance for medications, procedures, or therapies, especially important for children‌
  • How quickly the disease is expected to progress

Optic gliomas are often treated with chemotherapy to shrink the tumor and improve your vision. Newer molecularly targeted therapies such as mitogen-activated protein kinase inhibitors and bevacizumab are promising new treatments. If the tumor reaches the part of your brain that promotes endocrine function, you may need hormone replacement therapy to correct additional symptoms.

Surgery is possible but not common for this type of brain tumor unless the optic glioma is severely affecting vision or causing pain. If your doctor recommends surgery, you’ll be referred to a neurosurgeon who can help you decide what the best option is.

If the brain tumor doesn’t respond to chemotherapy, radiation is another option. This type of therapy projects high-energy rays from a special machine and shrinks the tumor by killing the cancer cells.