Optic Nerve Stroke (Anterior Ischemic Optic Neuropathy)

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KEY POINTS

• The optic nerve carries visual messages from the eye to the brain. When you have an optic nerve stroke, the blood vessels that supply nutrients and oxygen to the optic nerve get narrow or blocked. This causes sudden loss of vision.
• The treatment of an optic nerve stroke depends on the cause.

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What is an optic nerve stroke?

The optic nerve connects your eyes to your brain. It carries the visual messages that you see to your brain. When you have an optic nerve stroke the blood vessels that supply nutrients and oxygen to this nerve get blocked or too narrow, which causes sudden loss of vision.

After an optic nerve stroke, you may have permanent loss of some vision in one eye. A stroke of the optic nerve is not in the same as a stroke in the brain, and does not cause weakness or the loss of your ability to move your arms or legs.

What is the cause?

The most common type of optic nerve stroke may be caused by narrowed or blocked arteries or by a fall in blood pressure in the blood vessels that supply the optic nerve. You are at higher risk for this type of optic nerve stroke if you have:

• A small optic nerve
• Diabetes
• Infections such as herpes zoster or syphilis
• High blood pressure
• High cholesterol
• Rheumatoid arthritis, lupus, or other problems that affect your immune system
• Sleep apnea, which means you stop breathing for more than 10 seconds at a time many times while you sleep

Medicines to treat erectile dysfunction may increase the risk for optic nerve strokes.

Although not as common, a more serious cause of an optic nerve stroke is giant cell arteritis (GCA). GCA is a disease in which the arteries in the temples get swollen, narrowed, and sometimes completely blocked. GCA can affect any of the large arteries in your body and can be life threatening. An optic nerve stroke caused by GCA is most common in people over the age of 55.

What are the symptoms?

The most common sign of an optic nerve stroke is sudden loss of vision in one eye, or blurry vision or vision loss that comes and goes. If the optic nerve stroke is caused by low pressure in the blood vessels, you may have vision loss when you wake up in the morning. This may be due to a drop in blood pressure when you sleep.

Symptoms of an optic nerve stroke caused by giant cell arteritis include:

• Fever
• Headache or pain in your temples or scalp
• Stiffness and pain in the muscles of your neck, shoulders, lower back, and hips
• Pain when chewing
• Scalp pain or tenderness
• Tiredness
• Unexplained weight loss

How is it diagnosed?

Your eye care provider will ask about your symptoms and medical history and do exams and tests such as:

• An exam using a microscope with a light attached, called a slit lamp, to look closely at the front and back of your eye
• A test of the way your pupils react to light
• An eye test in which a camera takes pictures of the blood vessels inside your eye after dye is injected into a vein in your arm
• A visual field test, which uses spots of light to measure your central vision and how well you see things on all sides
• MRI, which uses a strong magnetic field and radio waves to show detailed pictures of your optic nerve and brain
• Blood tests

How is it treated?

The treatment of an optic nerve stroke depends on the cause. Giant cell arteritis should be treated right away with steroid medicines. Your vision may improve over several weeks or months after the optic nerve stroke. You may continue to have problems, and in some cases your vision may get worse.

How can I take care of myself?

Follow the full course of treatment your healthcare provider prescribes. Ask your healthcare provider:

• How and when you will get your test results
• How long it will take to recover
• If there are activities you should avoid and when you can return to your normal activities
• How to take care of yourself at home
• What symptoms or problems you should watch for and what to do if you have them

Make sure you know when you should come back for a checkup. Keep all appointments for provider visits or tests.

What can I do to help prevent an optic nerve stroke?

• Have regular eye exams.
• If you have high blood pressure, be sure you take your medicine.
• If you have diabetes, keep good control of your blood glucose.
• If you smoke, try to quit. Talk to your healthcare provider about ways to quit smoking.
• Eat a healthy diet.
• Try to keep a healthy weight. If you are overweight, lose weight.
• Stay fit with the right kind of exercise for you.

If you snore, ask your provider about a sleep study to check for sleep apnea.