Ischemic optic neuropathy is an eye condition that affects the optic nerve. It occurs when a blockage prevents blood flow to the optic nerve. This can cause vision loss or impairment.

The optic nerve, which is at the back of the eye, sends messages about what a person sees from the eye to the brain. Ischemic optic neuropathy happens when a blockage stops blood flow to this nerve.

Blood carries nutrients and oxygen to the optic nerve. Without blood flow, the optic nerve no longer works. This results in a loss of vision. Ischemic optic neuropathy can happen in one or both eyes.

This article explains what ischemic optic neuropathy is, including its symptoms, causes, and treatment options.

Ischemic optic neuropathy occurs when blood can no longer reach the optic nerve. This damages the optic nerve and can cause vision loss. Depending on the location of the blockage, doctors mainly refer to this condition as either anterior or posterior ischemic optic neuropathy.

Anterior ischemic optic neuropathy (AION) has two subtypes — arteritic and non-arteritic ischemic optic neuropathy — based on the cause of damage.

Arteritic ischemic optic neuropathy occurs due to inflammation in the optic nerve. This can result from a condition called giant cell arteritis.

Non-arteritic ischemic optic neuropathy is the more common type. It occurs when there is another cause of blocked blood flow to the optic nerve. Several factors can increase a person’s risk. Anything that can damage blood vessels increases the risk of damage to the optic nerve.

All types of ischemic optic neuropathy lead to a lack of blood flow and serious damage to the optic nerve.

Posterior ischemic optic neuropathy (PION) is less common than AION. Experts believe that PION is the result of a blockage of the blood supply to the retrobulbar optic nerve. PION differs from AION in that the optic nerve head appears typical. This makes PION challenging to diagnose.

Before ischemic optic neuropathy develops, a person may experience vision loss. This vision loss is usually painless but can develop quickly, sometimes within minutes, hours, or days.

If a person has giant cell arteritis, they may also experience:

  • a generally unwell feeling
  • muscle aches
  • aches in the temple
  • headaches that worsen when brushing the hair
  • jaw pain
  • pain in the temples

Anyone who experiences sudden vision loss should contact a healthcare professional. A person should also seek medical attention if they experience brief periods of vision loss. These episodes can be a symptom of impaired blood flow to the optic nerve, which increases the risk of ischemic optic neuropathy.

Anyone who has risk factors for ischemic optic neuropathy should check in regularly with a primary care doctor and an eye specialist.

There are several risk factors for developing ischemic optic neuropathy. Anything that impairs blood flow in the body can affect blood flow to the optic nerve.

Most cases of AION are non-arteritic. The risk factors include:

Giant cell arteritis can cause arteritic ischemic optic neuropathy. The risk of developing giant cell arteritis is highest in white women aged 70–80 years.

An eye specialist, usually an ophthalmologist, can diagnose ischemic optic neuropathy.

To make the diagnosis, an ophthalmologist will dilate a person’s pupils. This allows the ophthalmologist to get a better view of the optic nerve.

The specialist will look for changes in blood flow, damage to blood vessels, and changes in the optic nerve. The optic nerve will appear swollen upon examination in people with ischemic optic neuropathy.

A doctor may also order blood work to look for signs of inflammation that may indicate giant cell arteritis.

If giant cell arteritis is the cause of a person’s ischemic optic neuropathy, the person may take oral or injected steroid medication. Steroids can quickly reduce inflammation to prevent further vision loss. This can also help prevent vision loss in the other eye.

There is no proven way to fully restore vision in any type of ischemic optic neuropathy. If the condition has affected only one eye, the goal is to prevent vision loss in the other eye. The best strategy is to manage any risk factors.

Once a person develops ischemic optic neuropathy, vision loss is typically permanent in the affected eye. In some cases, a person may still have some peripheral (side) vision. Some people may find that their vision comes back after they start prompt steroid treatment.

Follow-up with an eye specialist is important. If the condition has occurred in only one eye, it is possible to prevent vision loss in the other eye, mainly by managing risk factors.

Ischemic optic neuropathy has many risk factors, and prevention is not always possible. Screening for risk factors and managing them can help prevent damage to the optic nerve.

Depending on a person’s risk factors, strategies for preventing ischemic optic neuropathy may include:

  • managing high blood pressure (hypertension) through exercise, stress management, dietary changes, and medications
  • managing cholesterol levels through exercise, dietary changes, and medications
  • quitting or cutting down on smoking
  • managing blood sugar levels through exercise, dietary changes, and medications
  • screening for sleep apnea and using a CPAP machine if necessary

Regular follow-up with an optometrist or ophthalmologist is important. An eye specialist can monitor a person’s eye health and identify any signs of damage early.

Ischemic optic neuropathy occurs when a blockage prevents blood flow to the optic nerve. This can damage the nerve and cause vision loss. The condition has several risk factors. People can manage their risk factors to prevent damage to the optic nerve.

It is important for a person who is at risk for ischemic optic neuropathy to check in regularly with an eye specialist. Vision loss from this condition is typically permanent. It may be possible to prevent vision loss in the other eye after a person receives a diagnosis of ischemic optic neuropathy.