This month we will continue our discussion on ischemic optic neuropathies. These can be classified as anterior or posterior depending on which part of the optic nerve is affected. The anterior type can be divided into two forms, non-arteritic and arteritic. We will discuss arteritic ischemic optic neuropathy (AION) this month.
What is ischemic optic neuropathy?
Ischemic optic neuropathy is when there is not enough blood flow to the optic nerve. This causes damage to the nerve which results in vision loss. An AION, also known as giant cell arteritis or temporal arteritis, is caused by inflammation of several arteries. Usually, patients present with painless vision loss in one eye that is like a cloudiness over the vision. Peripheral vision may also be lost. If the vision darkens for a few seconds or minutes and goes back to normal, this may be a mini stroke. It is important to see an ophthalmologist and/or primary care doctor right away.
An AION may also present with other symptoms including headache, scalp tenderness, pain while chewing, fatigue, fever, and weight loss.
How is an AION diagnosed?
A comprehensive exam including checking the vision and dilating the eyes is needed to diagnose an optic neuropathy. The dilated exam allows doctors to look at the optic nerve. A visual field test can be done to check the peripheral vision.
Lab tests and a temporal artery biopsy are often done to confirm the diagnosis. An MRI may also be ordered.
How are these treated?
The standard treatment is with high dose steroids for several months. Treatment can improve vision in many cases and without it, vision loss is permanent. Research is being done on non-steroid mediations for treatment.
Be sure to remember to see an ophthalmologist immediately for any blackouts of vision or vision loss.
Return next month for our discussion on posterior ischemic optic neuropathy (PION).