Central retinal artery occlusion – stroke of the eye
Central retinal artery occlusion (CRAO) is a stroke of the eye. A blood clot blocks the flow of blood to the eye, causing a sudden, profound, and painless loss of vision. The artery often unblocks quickly, but the damage to the retina caused by the few minutes of ischemia is irreversible. Treatment for CRAO primarily aims to prevent a similar event in the other eye or in the brain ( stroke ). There is no treatment that can restore vision in the affected eye.
What is OACR?
Central retinal artery occlusion (CRAO) is a thrombosis of the main retinal artery.
The obstruction is caused by: a clot from the heart, a buildup of cholesterol in an artery (atheroma) or arterial inflammation (Horton's disease).
This phenomenon is similar to that of a stroke, but contained within the eye.
Clinical forms
There are two types of ORA:
Branch arterial occlusion (BAOC) – Thrombosis of an accessory retinal artery.
Central retinal artery occlusion (CRAO) – Thrombosis of the main artery of your retina.
This is a form of stroke in the eye and it must be evaluated and treated immediately, just like a stroke.
Symptoms
The most common symptom of a central retinal artery occlusion is a sudden, painless loss of vision. It can affect the entire eye, in the case of a central retinal artery occlusion (CRAO), or a portion of the eye in the case of a branch retinal artery occlusion (BRAO).
The other symptoms are as follows
Visual field loss – Loss of peripheral vision
Scotoma – Presence of blind spots
If you experience any of these symptoms, consult a doctor immediately for evaluation and diagnosis.
Causes
Central retinal artery occlusions are most often linked to a blood or cholesterol clot originating from the heart or a neck artery.
Less commonly, CRAO is caused by inflammation of the arteries called giant cell arteritis or Horton's disease. It mainly affects patients over 70 years of age who present with headaches and recent fatigue.
Who is affected?
The disease is most common in men aged 60 and over. Having certain cardiovascular diseases increases the risk of cardiac artery disease (CAD). These include:
Smoking
Cardiovascular diseases
Hypercholesterolemia
High blood pressure
Narrowing of the carotid artery – the artery in the neck that supplies blood to the brain
Diagnosis
If you experience a sudden loss of vision, you should contact your ophthalmologist immediately. They will conduct a thorough examination to determine if you have suffered a retinal artery blockage.
Your ophthalmologist will dilate your eyes using eye drops to perform a fundus examination. They will observe a pale retina, devoid of the blood that normally supplies it.
He confirmed his observations with optical coherence tomography ( OCT ), revealing pallor with damage to the layers of the retina.
Other tests your ophthalmologist may perform include:
Fluorescein angiography – This imaging test uses a special camera to take pictures of the retina. A small amount of dye (fluorescein) is injected into a vein in your arm. The photographs show the poor circulation of the dye in the retina.
Your pupillary reflexes – Since the eye cannot see, reflexes are diminished.
Visual acuity – To determine the decrease in vision.
A visual field – To assess the impact.
Since arterial occlusions are on the border between ophthalmology, a stroke, and a clot originating from the heart, an evaluation by a neurologist will most often be requested urgently.
People with arterial occlusion are at increased risk of having a stroke in the days or weeks following the ocular arterial occlusion. Assessment of this risk includes the following tests:
A brain MRI – In search of an asymptomatic stroke.
A blood test – Looking for inflammation or a clotting disorder.
An ultrasound of your carotid arteries – the main blood vessels in your neck that send blood to your eyes and brain).
An echocardiogram (ultrasound of the heart) – Looking for a clot.
These tests help determine the causes of retinal artery blockage. It is best to perform them urgently, as with the evaluation of a stroke.
Treatment
Unfortunately, there is no validated treatment for retinal artery occlusions. The clot forms for a few minutes before the artery spontaneously reopens, leaving serious damage to the retina.
Visual recovery is most often very limited and the after-effects are significant.
Treatment therefore relies primarily on preventing recurrence. It includes:
An antiplatelet agent – Low-dose aspirin to thin the blood.
An antihypertensive drug – To limit cardiovascular risk.
A heart rhythm regulator – To regulate heart rate in case of arrhythmia.
Case of Horton's disease
In cases of central retinal artery occlusion (CRAO) caused by Horton's disease, urgent corticosteroid injections (bolus) must be administered to stop the disease and prevent the occurrence of occlusion in the other eye!
Complications
The risk of having a severe stroke resulting in motor disability or even death is very high in the month following a central retinal artery occlusion.