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Retinal Artery Occlusion (RAO)

A retinal artery occlusion (RAO) is a blockage of one of the arteries that supplies blood to the retina, the light-sensitive tissue at the back of the eye. Because the retina depends on a constant supply of oxygen and nutrients, an interruption in blood flow can cause sudden, painless vision loss.

Retinal artery occlusion is often considered the "eye's version of a stroke." In addition to being a vision-threatening emergency, it may signal an increased risk of stroke or other cardiovascular disease. Anyone experiencing sudden vision loss should seek immediate medical attention.

What Is the Retina?

The retina is the thin layer of nerve tissue lining the back of the eye. It converts light into electrical signals that travel through the optic nerve to the brain, allowing us to see.

The retina receives its blood supply from the central retinal artery and its branches. If one of these arteries becomes blocked, retinal cells can quickly become damaged due to lack of oxygen.

Types of Retinal Artery Occlusion

Central Retinal Artery Occlusion (CRAO)

CRAO occurs when the main retinal artery becomes blocked.

This often causes:

  • Severe, sudden vision loss
  • Vision loss involving most or all of one eye
  • Profound reduction in visual acuity

Branch Retinal Artery Occlusion (BRAO)

BRAO occurs when a smaller branch of the retinal artery is blocked.

Symptoms depend on the location of the blockage and may include:

  • Partial vision loss
  • Blind spots
  • Loss of peripheral vision
  • Central vision changes if the macula is involved

What Causes Retinal Artery Occlusion?

RAO most commonly results from an embolus, which is a small clot or cholesterol plaque that travels through the bloodstream and blocks a retinal artery.

Common sources include:

  • Cholesterol plaque from the carotid arteries
  • Blood clots originating from the heart
  • Calcific emboli from heart valves

Risk factors include:

  • High blood pressure
  • Diabetes
  • High cholesterol
  • Smoking
  • Heart disease
  • Carotid artery disease
  • Atrial fibrillation
  • Advanced age
  • Previous stroke or transient ischemic attack (TIA)

In younger patients, additional testing may be needed to evaluate for clotting disorders or inflammatory conditions.

Symptoms of Retinal Artery Occlusion

Symptoms typically occur suddenly and without pain.

Common symptoms include:

  • Sudden loss of vision in one eye
  • Blurred vision
  • Partial loss of the visual field
  • A dark area or shadow in vision
  • Sudden decrease in visual clarity

Why Is RAO a Medical Emergency?

Retinal artery occlusion requires urgent evaluation because it may indicate a serious underlying vascular problem.

Studies have shown that patients with RAO have an increased risk of:

  • Stroke
  • Heart attack
  • Future vascular events

For this reason, many patients require emergency evaluation similar to patients with cerebral stroke.

If you experience sudden vision loss, seek immediate medical attention or go to the emergency department.

How Is Retinal Artery Occlusion Diagnosed?

A retina specialist diagnoses RAO through a comprehensive eye examination and retinal imaging.

Dilated Retinal Examination

Characteristic findings may include:

  • Retinal whitening
  • A cherry-red spot in CRAO
  • Visible emboli within retinal arteries
  • Areas of retinal ischemia

Optical Coherence Tomography (OCT)

OCT can detect retinal swelling and structural changes caused by reduced blood flow.

Fluorescein Angiography

This imaging test evaluates retinal circulation and identifies areas of impaired blood flow.

Systemic Evaluation

Because RAO is associated with stroke risk, additional testing often includes:

  • Carotid artery imaging
  • Heart evaluation
  • Blood pressure assessment
  • Blood testing
  • Neurologic consultation

Treatment for Retinal Artery Occlusion

Unfortunately, there is no universally effective treatment that reliably restores vision after RAO. However, urgent evaluation remains critical.

Emergency Medical Evaluation

Patients often require:

  • Stroke assessment
  • Evaluation by emergency physicians or neurologists
  • Identification of the embolic source

Lowering Future Risk

Treatment focuses on reducing the risk of future vascular events.

This may include:

  • Blood pressure control
  • Cholesterol management
  • Smoking cessation
  • Diabetes management
  • Blood-thinning medications when appropriate
  • Treatment of carotid artery disease
  • Management of heart rhythm abnormalities

What Is the Prognosis?

The visual prognosis depends on:

  • Whether CRAO or BRAO occurred
  • The duration of interrupted blood flow
  • The extent of retinal damage
  • How quickly medical evaluation takes place

Patients with BRAO often retain better vision than those with CRAO.

While some patients experience partial visual improvement, others may have permanent vision loss.

Living After a Retinal Artery Occlusion

A diagnosis of RAO should prompt close attention to overall health.

Patients should:

  • Follow up with their primary care physician.
  • Work closely with neurologists and cardiologists when recommended.
  • Take prescribed medications consistently.
  • Stop smoking.
  • Maintain healthy blood pressure, cholesterol, and blood sugar levels.
  • Seek immediate care for any new neurologic or visual symptoms.

Addressing cardiovascular risk factors can help reduce the chance of future stroke and other serious complications.

Frequently Asked Questions

Is retinal artery occlusion the same as a stroke?

RAO is often considered a form of eye stroke because it results from interrupted blood flow to retinal tissue and carries an increased risk of stroke elsewhere in the body.

Can vision return after a retinal artery occlusion?

Some patients experience partial improvement, particularly with branch retinal artery occlusions. However, permanent vision loss is common, especially with central retinal artery occlusion.

Should I go to the emergency room if I suddenly lose vision?

Yes. Sudden, painless vision loss is a medical emergency and requires immediate evaluation.

More Information

For additional patient information, visit the American Society of Retina Specialists Retinal Artery Occlusion Page.

References

  • American Society of Retina Specialists (ASRS) – Retinal Artery Occlusion
  • American Academy of Ophthalmology – Retinal Artery Occlusions
  • EyeWiki – Central Retinal Artery Occlusion