One cause of a sudden loss of vision is referred to in medical terms as ischemic optic neuropathy. There are two types. One is caused by inflamed arteries in the eye that flow to the optic nerve, and one is caused by reasons other than enlarged arteries. Both types have different treatment options, but options can be dependent on nerve damage and the underlying causes.
What Is Ischemic Optic Neuropathy?
Signals that are carried to your brain from the eyes arrive via the optic nerve, where they are then turned into images for your brain to see. If the blood to your optic nerve decreases or does not flow at all, the nerve cannot get the nutrition or oxygen that it needs. At that point, it can stop working and begin to die.
When your eyes’ optic nerve does not receive the proper amount of blood flow, that is called ischemic optic neuropathy. In this condition, you can suddenly experience a loss of vision in one of your eyes or possibly both.
Both your central or detailed vision and your peripheral side vision can be affected by ischemic optic neuropathy. An optic nerve that has an injury cannot be fixed, so usually, if there is vision loss from ischemic optic neuropathy, it is permanent. Those with badly damaged optic nerves usually can still see peripherally, though.
Ischemic Optic Neuropathy Causes
There are two types of ischemic optic neuropathy. Arteritic anterior ischemic optic neuropathy (A-AION) is caused by artery inflammation and is very dangerous. A-AION can be fatal, first causing optic nerve damage that can cause permanent vision loss.
It is diagnosed three times as frequently in women compared to men. People over the age of 55 are also more commonly affected.
A key symptom that is vision-related is temporary and painless vision loss or blurriness. This can last minutes or hours before vision is restored. This is a warning sign before the loss becomes permanent. The effects on one or both eyes depend on the quickness of treatment.
Nonarteritic anterior ischemic optic neuropathy (NA-AION) is the most frequently seen form of ischemic optic neuropathy. Most cases occur in people over 50. Men and women are equally likely to be diagnosed. NA-AION is not caused by artery inflammation. Rather, it is caused by increased ocular pressure, artery narrowing, and subsequent blood pressure that decreases optic nerve blood flow. This can be caused by several conditions like diabetes, high cholesterol, sleep apnea, high blood pressure, or a sickle cell trait.
The main identification of NA-AION is painless, sudden blurriness or loss of vision in one eye upon waking. It is usually associated with the body's normal blood pressure drop during sleep and an underlying medical condition that triggers optic nerve blood flow interruption.
Ischemic Optic Neuropathy Symptoms
When blood flow to your optic nerve decreases, you will notice a darkening of your vision for a little while before it goes back to normal. This behavior is known as a transient ischemic attack. It usually precedes the onset of ischemic optic neuropathy.
You should see your doctor as soon as possible if you have this symptom, whether it be your primary caregiver or ophthalmologist. If you find the cause and treat it quickly, that can reduce further vision damage.
Other symptoms may include:
- Frequent muscle aches and headaches
- Experiencing pain while combing your hair
- Some pain when you eat
Ischemic Optic Neuropathy Diagnosis
Usually, an ophthalmologist will diagnose your ischemic optic neuropathy. They will look for signs of the condition via an eye exam. Usually, they give you eye drops to dilate your pupils. They will then look for swollen blood vessels or swelling of the optic nerve in the back of your eye.
Your doctor may also perform a blood test to look for signs of a condition known as giant cell arteritis. This is also known as inflammation of your blood vessels or temporal arteritis.
Ischemic Optic Neuropathy Treatment
A steroid pill may be prescribed by your ophthalmologist if your ischemic optic neuropathy is caused by inflammation of the arteries in your head. Steroids can prevent ischemic optic neuropathy from developing in your other eye.
Your doctor may also diagnose and treat other medical conditions that could put you at risk of developing ischemic optic neuropathy. These could include:
- high blood pressure
- migraine headaches
- clogged arteries
Unfortunately, there is no medical treatment for loss of vision from ischemic optic neuropathy. Your ophthalmologist could give accommodative treatments like magnifiers, or assistive technology items and techniques to help guide you through obstacles with low vision. Most people with ischemic optic neuropathy fortunately only have the condition in one eye.
Ischemic Optic Neuropathy Prognosis
Usually, if you are diagnosed with A-AION vs NA-AION, more vision will be lost, but that is dependent on the location and degree of injury caused to the optic nerve. Light and shade can remain hard to distinguish, and there can be some color blindness. Those with A-AION usually experience little improvement, if any at all.
About 40 percent of those with NA-AION eventually see some improvement in their central vision. About 25 percent of those with AION in one eye will develop it in the other, too, though, within 3 years. A minimal amount of patients will have numerous occurrences of AION in the same eye, with vision worsening over time.
Healthy lifestyle choices can lead to the prevention of heart disease, high blood pressure, and diabetes, all of which can otherwise lead to ischemic optic neuropathy. Cessation of smoking can also lower your risk.
If you are diagnosed, continuous medical appointments with your doctor can help to monitor your condition. If you are experiencing any symptoms, and they begin to worsen, your doctor can make recommendations to help you keep as much of your vision as possible.