What is Non-Arteritic Ischemic Optic Neuropathy (NAION)?

  1. What is the Definition of NAION ?
  2. What are the Symptoms of NAION?
  3. How is NAION Diagnosed?
  4. Is NAION the Only Cause of Abrupt Vision Loss?
  5. What is the Cure for NAION?
  6. What Treatment Can Patients Seek?

1. What is the Definition of NAION ?

NAION stands for Non-arteritic anterior ischemic optic neuropathy and is the most common cause of acute optic nerve injury in individuals 50 years or older.

Think of the optic nerve as the video cable, connecting your eye (which is like an ultra-sophisticated camera) to the brain, which processes the signals from the eye to create your vision. NAION interrupts those signals resulting in defects in your visual field.

2. What are the Symptoms of NAION ?

NAION causes fairly sudden, painless vision loss in one eye. The vision loss can appear as blurring in the center, lower or upper portion, or the entire vision scene while covering the better eye and viewing with the affected eye.

Typically NAION is unilateral at presentation, meaning occurring in only one eye. Eye pain is rare, severe pain is very rare, and pain on eye movement is extremely rare.

Commonly, patients will complain that they can't see objects below the straight-ahead line of sight. The vision loss can worsen over days to a week.

3. How is NAION Diagnosed ?

Although NAION is not due to blood clots or emboli from the carotid artery or heart, it is associated with the same risk factors that cause heart attack and stroke. Therefore, patients are evaluated for high blood pressure, high cholesterol, diabetes (high blood sugar), heart disease, carotid artery narrowing and sleep disorders.

From the outside the eye appears normal. It is not swollen or red. However, the eye doctor will evaluate patients for an abnormal visual acuity (less than "20/20"), specific defects in the measure of the visual field (peripheral vision test), and swelling in the part of the optic nerve seen by looking in the eye.

4. Is NAION the Only Cause of Abrupt Vision Loss?

NAION is not the only cause of abrupt vision loss. Abrupt vision loss without pain can be caused by a number of disorders, including inflammation of the optic nerve or blood vessels to the eye, stroke of the retina, hemorrhage in the eye, and retinal detachment, all of which need immediate evaluation by an eye doctor (ophthalmologist or optometrist). Most of these can be treated, but it is important to seek medical care as soon as possible.

5. What is the Cure for NAION ?

At this time, there is no therapy that has been proven to be effective for NAION. There are case series suggesting the benefit of many types of interventions: surgical, medical, and via electrical stimulation. However, the vast majority of eye care specialists understand that the data supporting these claims do not meet current standards of evidence.

If treatment can improve or prevent further vision loss, it must be started quickly since NAION, like a stroke of the brain, injures the optic nerve permanently.

6. What Treatment Can Patients Seek for NAION ?

NORDIC is working with a pharmaceutical company currently conducting a study on NAION.

NORDIC and Regenera Pharma have partnered to conduct a treatment trial evaluating Regenera's novel drug, an extract from a botanical source, that has been shown to stimulate the formation of new neurons and synapses, and may be effective in treating chronic NAION.  For more information on the clinical trial, click here.  To find a doctor participating in the trial, click here.

NORDIC also recently concluded a study with Quark Pharmaceuticals.  This trial tested a new drug that could protect the optic nerve from further damage due to factors related to acute ischemic injury. For more information on that clinical trial, you can visit the clinicaltrial.gov page for updates on that study..


Regardless of the cause of your vision loss, delaying care can result in worsening vision. If you do not know your diagnosis or are unsure, visit our FIND a DOCTOR for NAION page to schedule an initial examination. If you are eligible for the trial, the cost of the experimental drug is covered by the sponsor, Quark Pharmaceuticals.

NORDIC Contact

For questions regarding this webpage or help finding a study doctor please call 212-636-3516 or email info@NORDICclinicaltrials.com.