Optic Nerve Stroke (Anterior Ischemic Optic Neuropathy)
What is an optic nerve stroke?
The optic nerve is located behind the eye, and sends visual images to the brain. Poor circulation to the blood vessels that supply the front (anterior) part of the optic nerve can cause an optic nerve stroke. If the nerve tissue cannot get the nutrients and oxygen it needs, part of the nerve tissue will be lost. This causes loss of vision. A stroke of the optic nerve is not related to a stroke in the brain, and does not cause weakness or paralysis.
There are two main kinds of optic nerve stroke:
- The arteritic form is caused by a disease called giant cell arteritis (GCA). GCA is a disease in which the arteries in the temples get swollen, narrowed, and sometimes completely blocked.
- The nonarteritic form is caused by a brief fall in blood pressure in the blood vessels that supply the optic nerve.
How does it occur?
An optic nerve stroke is most common in people over the age of 55.
You are at higher risk for the form caused by low pressure in the blood vessels if you have:
- diabetes
- rheumatoid arthritis
- herpes zoster
- anemia
- sickle cell trait
- syphilis
- high or low blood pressure
- stomach ulcers
- heart disease
- migraines
- sleep apnea
What are the symptoms?
Optic neuropathy usually causes vision loss in one eye, which may worsen over several days. Signs of an optic nerve stroke caused by swollen or narrowed blood vessels include:
- blurred vision or vision loss that comes and goes
- achy joints
- fever
- headache
- neck pain
- pain in the temples
- pain when chewing
- scalp pain when you comb your hair
- tiredness
- unexplained weight loss
A common symptom of the form caused by low pressure in the blood vessels is vision loss when you wake up in the morning. This may be due to a drop in blood pressure when you sleep.
How is it diagnosed?
Your healthcare provider will ask about your symptoms, examine your eyes, and do tests. Tests you may have are:
- an exam with a microscope to look at the front of your eye
- an exam of the way your pupils react to light (your pupil may react abnormally)
- special photographs of your optic nerve
- a visual field test
- an MRI to look at your optic nerve and your brain
- blood tests to check for anemia and inflammation (if your provider suspects GCA)
You may be referred to a neuro-ophthalmologist (a healthcare provider who specializes in the eye and its relationship to the brain) or a neurologist.
How is it treated?
The treatment of an optic nerve stroke depends on the cause. If there is high pressure in the eye, medicine to lower the pressure may improve blood flow to the optic nerve. If the cause is giant cell arteritis, it is treated with steroid medicines, such as prednisone.
Taking low dose aspirin may reduce the risk of an optic nerve stroke in the other eye.
How long will the effects last?
After an optic nerve stroke, you may have permanent loss of some vision in one eye. Some people’s vision improves over several weeks or months after the stroke. Some people have problems with glare, and with seeing contrast (such as telling colors apart).
There are no medicines or surgeries to reverse vision loss from an optic nerve stroke.
How can I take care of myself?
- Have regular eye exams.
- Maintain normal blood pressure, blood sugar, and cholesterol levels with diet, exercise, and medicine, if prescribed.
- Do not smoke.
- Report any symptoms to your healthcare provider right away.
