Dr Ben Wild
Overview |
Our vision comes from light waves stimulating retinal photoreceptors and these photoreceptors transferring their signals through a multitude of other cells to the ganglion nerve cells. These ganglion cells bunch together and form the optic nerve. The optic nerve then sends the signal to the occipital lobe in the brain where vision is interpreted and recognized.
An image of a healthy retina and optic nerve.
Non-arteritic ischemic optic neuropathy (NAION) occurs when the blood vessels behind the eye, responsible for maintaining the optic nerve’s health, occlude. This cuts off blood supply to the nerve and damages the nerve. It occurs unilaterally (in one eye) but can occur in the other eye at a later date. It usually occurs over the age of 50 but does not usually occur in advanced ages.
An image showing optic nerve swelling and retinal hemorrhages consistent with a NAION.
Signs and Symptoms |
Signs
Optic nerve redness and swelling, broken blood vessels around the nerve, if longstanding, the nerve starts to atrophy (die off) and becomes pale white.
Symptoms
Sudden painless vision loss usually after waking up, blind spot on the bottom or top half of vision, decreased vision.
Causes and Risk Factors |
Causes
Occluded posterior ciliary artery (one of the several that nourishes the optic nerve behind the eye).
Risk Factors
High blood pressure, diabetes, high cholesterol, cardiovascular disease, anti-phospholipids antibody syndrome, hyperhomocysteinemia, sleep apnea, cataract surgery, birth control, medications for erectile dysfunction.
Prevention and Treatment |
Prevention
There are no known preventative measures other than a healthy lifestyle.
Treatments
· There are currently no known treatments.
Prognosis |
The optic nerve swelling in NAION will decrease over time but will result in atrophy of the nerve. Visual acuity and blind spots will typically improve over time with 50% of patients reaching vision 20/30 or better but 25% of patients never exceed 20/200 or legally blind. There is a 15% chance of it occurring in the other eye within the proceeding 5 years.
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