What is Ischemic Optic Neuropathy?
Anterior ischemic optic neuropathy is a disease that can be devastating to eyesight. Commonly occurring in people who are middle aged or elderly, ischemic optic neuropathy can be likened to a stroke, except that in this case, the stroke occurs in the eye instead of the brain.
The optic nerve, which contains more than one million nerve fibers, is feed by tiny blood vessels that deliver essential oxygen and nutrients to the eye. If ischemia – poor circulation – develops in the blood vessels that feed the optic nerve, nerve tissue can potentially be destroyed, with a resulting loss of eyesight. This nerve tissue cannot regenerate.
There are two different causes of ischemic optic neuropathy.
- The arteritic form of the condition is caused by a disease known as giant cell arteritis, which can cause fatigue, pain, anemia, joint pain, and vision loss due to an ischemic optic episode. Giant cell arteritis is a potentially dangerous disease which may cause a fatal stroke if left untreated.
- The non-arteritic form of the condition is associated with transient poor circulation, typically caused by a temporary drop in blood pressure. People with diabetes, rheumatoid arthritis, and systemic low blood pressure, as well as coronary conditions, are at higher risk of a non-arteritic ischemic episode.
Symptoms and Diagnosis
Ischemic optic neuropathy is a ‘stroke’ that occurs in the eye. Therefore, there are no symptoms of paralysis, weakness, or confusion, as there are in a stroke that occurs in the brain.
Instead, symptoms of ischemic optic neuropathy relate to loss of vision, usually in one eye. The condition usually occurs with little warning – the individual will typically experience a sudden loss of vision, or drop in vision quality, that may grow progressively worse over time. Both vision loss, and visual field loss, may result from an ischemic optic episode. Some people may also experience a reduction in contrast sensitivity (the ability of the eye to detect shade variation).
Ischemic Optic Neuropathy Treatment and Prevention
Treatments available for anterior ischemic optic neuropathy are very limited. For some people, medication that reduces intra-ocular blood pressure may help improve blood flow through the optic nerve. However, diagnosing and treating the underlying cause of the ischemic episode is usually the most effective way of reducing further vision loss.
If the ischemic episode was caused by giant cell arteritis, early detection and treatment may save the patient’s life as well as their vision.
University of Iowa Department of Ophthalmology: Anterior Ischemic Optic Neuropathy
Windsor, R. and Windsor, L. Understanding AION: Anterior Ischemic Optic Neuropathy