ISCHEMIC OPTIC NEUROPATHY

WHAT IS ISCHEMIC OPTIC NEUROPATHY?

Ischemic optic neuropathy, known as ION, is a vision threatening condition that occurs secondary to poor blood flow to the optic nerve. The optic nerve carries sight from the eye to the brain.

WHAT ARE THE SYMPTOMS OF ION?

Sudden loss of central or side vision is the most common symptom. You may notice loss of side vision in the lower half of reading vision. Vision loss is usually at its worst when first noticed and in most eyes permanently remains at this level. In a few eyes, vision either progressively worsens or improves over days to weeks. ION generally does not cause any other symptoms, such as pain or double vision.

Temporal arteritis (also known as giant cell arteritis) is one of many causes of ION. The symptoms of this cause of ION include, headaches and tenderness in the temples (the area of the head between the ears and the eyes). Joint aches and pains most commonly affecting the shoulders and hips may be present in people with this blood vessel disorder. They may also feel tired and run a fever, combined with recent weight loss. There may be pain on chewing and neck stiffness may be present.

HOW IS ION DIAGNOSED?

Your eye doctor will perform a complete eye examination. Decreased blood flow usually results in swelling of the optic nerve, which your eye doctor can see when he or she looks into your eye.

A visual field test will also be performed. Your eye doctor may recommend a check of blood pressure or a blood test for diabetes. In addition, a blood test and/or biopsy of an artery in the temple to diagnose temporal arteritis or giant cell arteritis may be recommended.

WHAT CAUSES ION?

The most common type of ION occurs in individuals over 40 years of age and is usually not related to other illness. ION may be more common in people with diabetes or high blood pressure.

A less common type of ION occurring in people over 60 years of age is temporal or giant cell arteritis. This disease is an inflammation of certain arteries, including those in the eye. Rarely, ION can occur after loss of large amounts of blood.

CAN ION BE TREATED?

ION has no proven treatment. Depending on the cause, there is about a 50% risk that the other eye may lose vision.

There is no treatment to improve vision. However, some patients will experience spontaneous improvement of their vision over time.

Patients with ION caused by temporal arteritis or giant cell arteritis have a high chance of the other eye being affected unless treated with steroids. The purpose of steroids is to prevent ION in the other eye but this treatment rarely improves vision which is lost in the first eye.

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