Eye Disorders: Anterior Ischemic Optic Neuropathy
Anterior Ischemic Optic Neuropathy (AION) means that the front end of the optic nerve, where it attaches to the back of the eye, has suffered a loss of blood flow. This almost always results in vision loss, which is often severe. There are two types of AION. The arteritic form is caused by temporal arteritis, an autoimmune inflammatory disorder. Arteritic AION usually occurs in the elderly, and is treated initially with prednisone. The non-arteritic form is caused usually by a blood clot in the vessels supplying the nerve, and is seen most commonly in people with vascular risk factors (like high blood pressure, diabetes, etc.) and a congenitally "crowded" optic nerve appearance. Non-arteritic AION can be associated with certain medications (like Viagra), sleep apnea, and low blood pressure as well. Unfortunately there is no proven treatment for non-arteritic AION.
The North American Neuro-Ophthalmology Society publishes a web site with good patient information on this condition. When you click on the link, the patient information will open in a new browser window.