Arteries are the vessels that carry blood from your heart to the rest of your body. That blood is rich in oxygen, which all your tissues and organs need to work properly.
In giant cell arteritis (GCA), arteries in your head become inflamed. As these blood vessels swell, they narrow, which limits the amount of blood they can carry. A lack of blood is called ischemia.
Too little enough blood can damage your eyes and cause sudden vision loss. Blindness in GCA is primarily due to ischemic optic neuropathy (ION), where the optic nerve becomes damaged. Starting on treatment quickly can prevent you from losing your sight.
Narrowing of the arteries in GCA reduces blood flow to the eyes. A lack of blood damages the optic nerve and the other structures you need to see clearly. Depending on which part of your eye loses blood flow, you can have problems ranging from double vision to sight loss.
GCA also reduces blood flow to parts of your brain that help you see. This loss of blood can cause you to lose your side vision.
GCA often affects the blood vessels in your head. The main symptoms are severe headaches and pain in your head, especially around your temples. Other common symptoms include jaw pain, fever, and tiredness.
When GCA affects the eyes, symptoms can include:
- double vision (diplopia)
- pain around the eyes
- flashing lights
- color changes
- blurred vision
- temporary loss of vision in one eye
- sudden blindness in one or both eyes
Some people have no symptoms until they’ve already lost their vision.
Narrowing or closing of the blood vessels to the eyes can lead to blindness. Vision loss can happen very quickly. About 30 to 50 percent of people with untreated GCA will lose vision in one eye.
Sometimes, blindness occurs in the other eye 1 to 10 days later. Without treatment, about one-third of people who’ve lost vision in one eye will lose sight in the other eye. Once you’ve lost your sight, it won’t come back.
If you’ve been diagnosed with GCA or you have vision symptoms, see an eye doctor.
Tests to diagnose vision loss from GCA include:
- Check of your visual acuity. Your visual acuity is the clarity and sharpness of your vision. You’ll read from an eye chart. Normal visual acuity is 20/20, which means you’re able to read from a distance of 20 feet what someone with normal vision can read at that distance.
- Dilated eye exam. Your eye doctor will use drops to dilate, or widen, your pupil. This test can reveal damage to your retina and optic nerve.
- Check of the artery in your head. Your eye doctor may gently press on the artery along the side of your head to see if it is thicker than usual — a sign of GCA.
- Visual field test. This test checks your peripheral (side) vision.
- Fluorescein angiography. Your eye doctor will inject a dye into a vein in your arm. The dye will travel to blood vessels in your eye and make them fluoresce, or shine. Then a special camera will take pictures of your eye to help your doctor spot any problems with the blood vessels.
Treatment for GCA primarily involves taking high doses of corticosteroid drugs like prednisone. It’s important to start taking these medications as soon as possible to preserve your vision. Your doctor may not wait until you’re formally diagnosed with GCA to start you on a steroid.
Once you’re on treatment, your symptoms should improve within 1 to 3 days. After your symptoms are under control, your doctor can start gradually lowering your steroid dose. But you may need to stay on these medications for as long as two years.
If your disease is severe and you’ve already lost vision, your doctor might give you very high doses of steroids through an IV. Once your condition has improved, you’ll switch to steroid pills.
Steroid drugs can cause side effects like weak bones and an increased risk of cataracts. Your doctor can recommend treatments to help manage these problems.
Steroids work very well at controlling GCA. These medications can’t bring back the vision you’ve already lost, but they can preserve the vision you have left.
If steroids don’t relieve your vision problems and other symptoms, you may need to take other medications along with steroids or instead of them. Methotrexate and tocilizumab (Actemra) are two other drugs that are used to treat this condition.
Losing sight can have a big impact on your life, but you can learn to make the most of the vision you have left. Try these tips:
- Place brighter lights around your home and office. Shine a light directly on whatever task you’re doing, whether you’re reading, sewing, or cooking.
- Use bright colors to improve the contrast between objects. For example, you might put a brightly colored throw on a white chair to make the chair stand out.
- Buy large-print books, clocks, and watches. Increase the font size on your computer and cell phone.
- Use magnifiers and other low-vision aids to help you see more clearly.
Vision loss from GCA can happen quickly. If you have symptoms like double vision, blurred vision, eye pain, or vision loss in one eye, see your eye doctor or go to an emergency room as soon as possible.
If your doctor suspects that you have this condition, taking high-dose steroids is the best way to protect your sight. Follow your doctor’s instructions carefully and take all of your medication. Stopping treatment too soon could put your sight at risk.