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. We will discuss posterior ischemic optic neuropathy (PION) 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. A PION causes painless vision loss in one or both eyes. The vision loss is usually sudden but can worsen over days to weeks. Most patients are over the age of 50 but this can occur at any age. There are several causes of PION. It can be related to diabetes, high blood pressure, high cholesterol, glaucoma, and giant cell arteritis. One type of PION may also be caused by surgery, most commonly spinal surgery. Risk factors include male gender, obesity, sleep apnea, low blood pressure during surgery, and anemia.
How is a PION 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 an MRI may also be ordered.
How are these treated?
The standard treatment for most cases is with high dose steroids for several months. Treatment can improve vision in many cases and without it, vision loss is permanent. There is less data for PION after surgery. Minimizing surgery times and replacing fluids and blood can help.
Be sure to remember to see an ophthalmologist immediately for any blackouts of vision or vision loss.
Return next month for a discussion on a new topic!