Retinal Artery Occlusion
Definition
Retinal artery occlusion (RAO) occurs when blood flow through a retinal artery becomes blocked, depriving the retina of oxygen. It is considered an ocular emergency and is often described as the eye’s equivalent of a stroke. Immediate evaluation is critical to reduce the risk of permanent vision loss and identify potential cardiovascular disease.
Types
1. Central Retinal Artery Occlusion (CRAO)
- Blockage of the main retinal artery.
- Usually causes severe vision loss affecting most of the retina.
2. Branch Retinal Artery Occlusion (BRAO)
- Blockage of one of the smaller retinal artery branches.
- Causes vision loss in only part of the visual field.
Causes
The most common causes include:
- Cholesterol or blood clot emboli blocking the retinal artery
- Carotid artery atherosclerosis (plaque in neck arteries)
- Cardiovascular disease and emboli from the heart
- Inflammatory diseases affecting blood vessels (arteritis)
- Hypercoagulable blood disorders
Risk Factors
- Age over 50 years
- High blood pressure
- Atherosclerosis
- Diabetes mellitus
- Heart disease
- Smoking and vascular disease
Symptoms are typically sudden, painless, and affect one eye.
Common Symptoms
- Sudden severe loss of vision in one eye
- Partial visual field loss (especially with BRAO)
- Sudden dimming or blackout of vision
- Usually no eye pain
Why It Is an Emergency
Patients with retinal artery occlusion have an increased risk of:
- Stroke
- Heart attack
- Other serious cardiovascular events
Because of this association, rapid medical evaluation is recommended.
Dilated Retinal Examination
Allows direct visualization of retinal ischemia and arterial blockage.
Retinal Imaging
OCT and fluorescein angiography may help evaluate retinal damage and blood flow.
Systemic Evaluation
- Carotid artery imaging
- Cardiac evaluation
- Stroke assessment
Retinal artery occlusion often requires coordination between ophthalmology, neurology, and primary care teams.
Emergency Medical Evaluation
Immediate referral is recommended because RAO is treated similarly to an acute stroke.
Identify and Treat Underlying Cause
- Evaluate carotid artery disease
- Assess for heart disease
- Manage vascular risk factors
Vision Prognosis
- Unfortunately, no consistently effective treatment exists to restore vision once significant retinal damage has occurred.
- Prompt diagnosis may help reduce the risk of future strokes and cardiovascular events.
- Control blood pressure, cholesterol, and diabetes
- Stop smoking
- Manage cardiovascular disease risk factors
- Seek immediate care for sudden vision loss
Retinal artery occlusion is a sudden blockage of blood flow to the retina and is considered an eye stroke. Patients typically experience painless, sudden vision loss in one eye. Because RAO is strongly associated with future stroke and cardiovascular disease, it requires urgent medical evaluation. Prevention focuses on controlling vascular risk factors and maintaining cardiovascular health.
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