This month we will begin 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 non-arteritic ischemic optic neuropathy (NAION) 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. Usually, patients present with painless vision loss in one eye that is like a cloudiness over the vision. Peripheral vision may also be lost. Occasionally, one may have a headache or pain around the eye. 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.
What are the risk factors for developing an NAION?
Most cases are not associated with a specific cause but there are some conditions that can put one at higher risk of developing this neuropathy:
- High blood pressure
- High cholesterol
- Sleep apnea
- Heart disease
- Over the age of 50
How is an NAION 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 may be done to check the peripheral vision.
Lab tests and an MRI may be done to rule out other causes of optic neuropathies.
How are these treated?
Unfortunately, there is no treatment to restore vision with an NAION. Doctors will treat other risk factors (lowering blood pressure and cholesterol). Low vision aids, such as magnifiers, can help with daily activities.
Be sure to remember to see an ophthalmologist immediately for any blackouts of vision or vision loss.
Return next month for our discussion on arteritic ischemic optic neuropathy (AION).