Illustrative stock photograph; not a CEI patient, treatment result or clinic equipment.
Most people know that sudden weakness on one side of the body or slurred speech can mean a stroke. Fewer know that the eye can have a stroke too. When blood flow to the retina is blocked, vision in one eye can disappear suddenly, often without any pain.
This is called a retinal artery occlusion, sometimes known as an “eye stroke.” It is a medical emergency, both for your sight and because it can be linked to a stroke in the brain.
Key Takeaways
- A retinal artery occlusion (RAO) happens when blood flow to the retina is blocked.
- The most common symptom is sudden, painless vision loss in all or part of one eye.
- Go to a hospital emergency department right away. Don’t wait to see if it improves.
- People who have an RAO are at high risk of a brain stroke, especially in the following weeks.
- Seek help even if the vision loss is temporary.
What Is a Retinal Artery Occlusion?
The retina is the light-sensitive layer at the back of the eye. It needs a constant supply of blood to work. Arteries carry that blood from the heart to the eye.
Sometimes cholesterol, platelets (blood-clotting cells) or calcium builds up and blocks one of these arteries, much like a kink in a hose stops the flow of water. Without blood flow, the retina can’t work properly, and vision can be lost temporarily or permanently.
There are two main types:
- Central retinal artery occlusion (CRAO) blocks the main artery to the retina and can cause immediate, painless vision loss in the whole eye.
- Branch retinal artery occlusion (BRAO) blocks a smaller artery and affects part of the vision. In some cases, it causes no symptoms.
Symptoms
The most common symptom is sudden, painless vision loss in one eye. Other sudden changes can include:
- Loss of side (peripheral) vision
- Distorted vision, where things look wavy or out of shape
- Blind spots or a dark area in your vision
- Blurred vision
Eye strokes almost always affect just one eye. Vision loss that comes and goes can be a warning sign too, so get help even if your sight returns.
What to Do: Go to the Emergency Department Now
If you suddenly lose vision in one eye, go to the nearest hospital emergency department right away. Studies suggest that leaving an RAO untreated for just over an hour and a half can lead to permanent vision loss, and someone with an RAO may be having a brain stroke at the same time.
Call 911 if sudden vision loss comes with other stroke signs, such as face drooping, arm or leg weakness, trouble speaking, confusion or a severe headache. Don’t drive yourself. After hours, our office voicemail directs callers to Saskatoon City Hospital at 306-655-8000 to ask for the ophthalmologist on call, or you can go directly to the nearest emergency department. In an emergency, you do not need to call us first.
Illustrative stock photograph; not a CEI patient, treatment result or clinic equipment.
Who Is at Risk?
Retinal artery occlusion is most common in people in their sixties, especially men, although women can have it too. Risk factors include:
- Smoking
- High blood pressure
- High cholesterol
- Diabetes
- Heart or lung disease
- Obesity
- Narrowing of the carotid (neck) arteries
- Blood clotting problems
- Older age
How Is It Diagnosed?
Doctors look closely at the retina with a dilated eye exam and may do other tests, such as:
- Retinal photographs or OCT scans
- Fluorescein angiography, where a dye is injected into a vein in the arm and photographed as it moves through the retina’s blood vessels
- Eye pressure and pupil checks
- Side vision testing
Because an RAO is linked to stroke risk, you may also have tests to look for the source of the blockage, such as an ultrasound of the neck arteries, scans of the blood vessels in the head and neck, or an ultrasound of the heart.
Treatment
There are a few treatments doctors may try, but none has been proven to work every time. They may include breathing a carbon dioxide-oxygen mixture to widen the retina’s arteries, removing a little fluid from the eye or massaging the eye to help move the clot, or, for some people, a clot-dissolving drug given into a vein. That medicine must be given within hours of vision loss and carries a risk of bleeding in the brain, so only certain people can have it.
Often, vision loss from an RAO is permanent, especially with a central occlusion. Some people do regain some vision, though it may not be as good as before.
Because an RAO raises the risk of a brain stroke, your other doctors will also look at your risk factors, such as blood pressure, cholesterol and diabetes.
After an Eye Stroke
Even if your vision doesn’t improve, keep seeing your eye doctor. More eye complications can develop later, so your eye doctor will want to monitor and treat any problems to help prevent further vision loss. Take your medicines as prescribed.
Frequently Asked Questions
Does an eye stroke hurt?
Usually not. That’s why sudden painless vision loss should never be ignored.
My vision came back after a few minutes. Do I still need help?
Yes. Temporary vision loss can be a warning sign of an eye or brain stroke. Get assessed right away.
Can I wait until morning to see my eye doctor?
No. Go to the emergency department immediately.
Is an eye stroke the same as a retinal vein occlusion?
No. An artery occlusion blocks blood flowing into the retina, while a vein occlusion blocks blood draining out. Both need prompt care.
Book Your Consultation
For sudden vision loss, go to the emergency department first. For follow-up eye care after an eye stroke, our ophthalmologists can help. Book your consultation: call our Saskatoon office at 306-244-4111, Monday to Friday, 7 am to 4 pm. Conlon Eye Institute is in the Medical Arts Building, 341-750 Spadina Crescent East, Saskatoon, SK S7K 3H3.
References
- American Academy of Ophthalmology. What Is a Retinal Artery Occlusion? https://www.aao.org/eye-health/diseases/what-is-stroke-affecting-eye — supports definition, causes (cholesterol, platelets or calcium blocking arteries; hose analogy), CRAO and BRAO (BRAO sometimes without symptoms), sudden painless vision loss and other sudden symptoms, going to an emergency department right away, risk factors and age/sex pattern, diagnostic tests (dilated exam, fluorescein angiography, pressure, pupil, OCT, visual field, carotid ultrasound, vessel imaging, echocardiogram), high brain-stroke risk up to four weeks, permanent loss after untreated RAO just over 90 minutes, unproven treatments (carbon dioxide-oxygen breathing, fluid removal or eye massage, clot-dissolving infusion within hours with brain-bleeding risk), frequent permanent vision loss, and continuing eye follow-up because later complications can occur.
- Cleveland Clinic. Eye Stroke. https://my.clevelandclinic.org/health/diseases/24127-eye-stroke — supports usually painless, sudden vision loss or change in one eye including blurred vision and blind spots or darkness, almost always one eye, and seeking help even for temporary vision loss.
- Centers for Disease Control and Prevention. Signs and Symptoms of Stroke. https://www.cdc.gov/stroke/signs-symptoms/ — supports sudden stroke warning signs and calling 911.
About the Author
Dr. M. Ronan Conlon has practised ophthalmology in Saskatoon since 1994. He completed fellowship training in ocular pathology at Harvard University and in oculoplastic surgery at the University of Iowa. In 1996 he brought laser vision correction technology to Canada from Germany, and he specializes in oculoplastic surgery, LASIK, ASL (PRK) and refractive cataract surgery. With the establishment of the Conlon Eye Institute, Dr. Conlon has drawn on decades of experience in LASIK, RLE surgery, refractive cataract surgery, and oculoplastic surgery. He has also served as Head of Ophthalmology and Chief of Staff with the Saskatchewan Health Authority.
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