A retinal stroke is a debilitating and dangerous condition in which there is a blockage of the retinal artery.
This condition is most commonly caused by a lack of pressure or perfusion of the tissue of the retina. This means that blood is not able to flow freely to and from the retina.
Treatments for an eye stroke include medication, laser treatment, massage, paracentesis, and hyperbaric oxygen therapy.
What Is a Retinal Stroke?
A retinal stroke, medically known as a retinal artery occlusion, is a blockage of the retinal artery due to a blood clot.
The retina plays an important role in sending visual signals to the visual cortex. Because oxygen-rich blood flow is necessary for this to occur, any blockage of the vessels in the retina can lead to a permanent loss of vision. Immediate medical treatment is necessary if a blood clot occurs.
A retinal stroke can also be caused by a solid substance blocking an artery, such as an accumulation of plaque or an infection. This type of blockage is referred to as an embolism.
Approximately 1 to 2 out of every 100,000 people is estimated to have a retinal stroke each year.
Types of Retinal Strokes
Retinal strokes fall into different classifications:
- Central retinal artery occlusion: When this occurs in the main artery of the retina, it is known as a central retinal artery occlusion (CRAO). This type of occlusion is the most severe form and can lead to a complete loss of vision.
This eye stroke can occur in a progressive manner due to the blood vessels in the eye becoming constricted and ultimately blocked. This is referred to as thrombosis.
- Branch retinal artery occlusion: BRAO refers to a blockage in one of the smaller arteries within the eye, similar to a branch that is connected to the larger trunk of the tree. The impacts of this type of blockage are seen in the smaller area of eye.
- Twig retinal artery occlusion: This type occurs when there is blockage in an even smaller blood vessel, similar to a twig that is located on the branch that is connected to the trunk of the tree.
Symptoms of a Retinal Stroke
Retinal strokes are often painless. However, the first and primary symptom of this condition is a loss of vision or significant change in vision in one eye. This may also include the following:
- Progressively worsening changes in vision
- Darkness or blind spots in the visual field
- Vision that is blurred
- Flashes in vision or floaters (small, darkish shapes that float across the visual field, often appearing as sports, threads, lines, or a cobweb pattern)
The following risk factors are most commonly associated with a retinal stroke:
- A previous retinal stroke or another form of stroke
- Older than 60
- Elevated blood pressure (hypertension)
- Coronary artery disease
- Accumulation of plaque within blood vessels (atherosclerosis)
- Elevated cholesterol (hyperlipidemia)
Causes of an Eye Stroke
A retinal stroke is caused by impaired blood flow to the retina. This interruption in blood flow may be underpinned by infection or plaque that breaks off from a different region of the body, such as within the heart. Again, this is referred to as an embolism.
Progressively increasing thickness of the blood can also lead to clotting, as is the case with thrombosis.
Blockages that occur to the retina can result in an increase in ocular pressure. In some cases, this pressure can result in damage to the optic nerve, which is what takes place with glaucoma.
Diagnosis of a retinal stroke is made by an ophthalmologist. First, your medical history will be taken, and this professional will ask about your symptoms.
A complete eye exam will then be performed. This will include an ophthalmoscopy, in which a bright light is shined, and an ophthalmoscope is used to examine the eyes. The eye doctor will dilate your eyes in order to examine the retina as well as the optic nerve. This will allow them to determine if there is a pale color present or if there is inflammation of the optic disc.
Your ophthalmologist will also compare your normal eye with the affected one to identify any changes.
Additional steps that will be performed to reach a diagnosis include the following:
- Fluorescein angiography tests, which involve the use of a special dye that indicates how blood flows into the eyes
- Fundus photography tests, which provide images of the part of the eye containing the retina
- Optical coherence tomography, which show the blood vessels within the retina in detail
If it is suspected that you have condition such as temporal arteritis, your doctor may order one or more of the following tests:
- Blood tests to examine inflammation markers
- An echocardiogram
- An ultrasound
Treatment of a Retinal Stroke
The following treatments are most commonly prescribed in the case of a retinal stroke:
- Medication to reduce pressure that accumulates in the eye and/or to dissolve a blood clot that is present.
- Laser treatment, which can help close up blood vessels that are leaking.
- Hyperbaric oxygen therapy, which involves the respiration of pure oxygen in a specialized chamber to stop bleeding
- Paracentesis, which involves use of a needle to extract fluid from the eye in order to relieve pressure.
- Massage of the closed eyed to stimulate blood and oxygen flow
Some risk factors for a retinal stroke can be mitigated. It is advised that you take the following steps if you demonstrate a risk for this condition:
- Quit smoking (if applicable).
- Get regular exams from your eye doctor.
- Consume a healthy, balanced diet, and get regular cardiovascular exercise.
- Manage blood sugar levels if you have diabetes.
- Maintain your blood pressure, cholesterol level, and eye pressure in healthy ranges. Have these checked regularly by your health care provider.
What to Do if You Suspect a Retinal Stroke
If you suspect a retinal stroke, seek emergency medical care. Any clot-busting medication must be taken within 4.5 hours of the onset of your symptoms, so see a doctor promptly.
Eye Stroke Care. (2022). Duke Health.
The Incidence of Central Retinal Artery Occlusion in Olmsted County, Minnesota. (July 2011). American Journal of Ophthalmology.
Stroke and Risk Factors in Patients With Central Retinal Artery Occlusion. (December 2018). American Journal of Ophthalmology.
What’s an Eye Stroke? (2022). British Heart Foundation.
Last Updated December 20, 2022
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