Retinal Artery Occlusion

Overview

Retinal artery occlusion is a blockage of the artery that supplies oxygen-rich blood to the retina, the light-sensing layer at the back of the eye. When this blood flow is cut off, the affected part of the retina is starved of oxygen and its cells begin to die quickly. The result is sudden, usually painless, and often severe vision loss in one eye.

Because it works much like a stroke in the brain, retinal artery occlusion is sometimes called an "eye stroke" and is treated as a medical emergency. The same processes that cause it can also cause a brain stroke, so it is an important warning sign of serious cardiovascular disease. Sudden vision loss in one eye requires immediate emergency care, both to try to save vision and to identify and treat the underlying cause.

Symptoms

Symptoms come on suddenly and affect one eye. They include:

• Sudden, painless loss of vision in one eye, which can be partial or near-complete
• A dark or missing area in part of the visual field if only a branch artery is blocked
• Vision that may briefly dim and recover before a permanent loss (a warning sign called amaurosis fugax)

The vision loss is usually profound and does not improve on its own. This is a medical emergency. Seek emergency eye or hospital care immediately. If sudden vision loss occurs with stroke-like symptoms such as facial drooping, arm weakness, or slurred speech, call emergency services right away.

Causes

Retinal artery occlusion is most often caused by a clot or piece of debris that travels through the bloodstream and lodges in the retinal artery, blocking blood flow. Common sources and causes include:

• Emboli from the carotid arteries: fatty plaque in the neck arteries can break off and travel to the eye.
• Emboli from the heart: clots related to an irregular heartbeat or heart-valve problems.
• Atherosclerosis: hardening and narrowing of the arteries.
• Giant cell arteritis: an inflammation of arteries, especially in older adults, that can block the retinal artery and threatens the other eye if untreated.
• Clotting disorders: conditions that make the blood more prone to clotting, particularly in younger patients.

Risk Factors

Risk factors are largely the same as those for stroke and heart disease, including:

• High blood pressure
• High cholesterol and carotid artery disease
• Diabetes
• Smoking
• Irregular heartbeat (atrial fibrillation) and heart-valve disease
• Older age
• Giant cell arteritis
• Blood-clotting disorders

Diagnosis

Diagnosis is made quickly through eye examination and is followed by urgent testing to find the cause, much like a stroke evaluation. This includes:

• Dilated eye examination: the retina shows characteristic pale swelling and a narrowed artery, sometimes with a visible embolus.
• Optical coherence tomography (OCT): shows the affected retinal layers.
• Fluorescein angiography: demonstrates the blocked blood flow.
• Blood tests: including markers of inflammation to check for giant cell arteritis, which needs urgent treatment.
• Carotid ultrasound, heart imaging, and stroke workup: to locate the source of the clot and assess stroke risk.

Treatment

Retinal artery occlusion is treated as an emergency. Restoring blood flow quickly offers the only chance to save vision, but the window is short and results are often limited. Care includes:

• Immediate evaluation: urgent assessment, often in a hospital, because of the strong link to stroke.
• Attempts to restore flow: measures such as eye massage, lowering eye pressure, or, in selected centers and within a narrow time window, clot-dissolving treatment.
• Treating giant cell arteritis urgently: high-dose steroids if this inflammatory cause is suspected, to protect the other eye.
• Stroke prevention: finding and treating the source of the clot, controlling blood pressure, cholesterol, and irregular heart rhythm, and using blood thinners or antiplatelet drugs as advised.

Even when vision cannot be restored, the evaluation is vital to prevent a future stroke.

Prevention

Preventing retinal artery occlusion and the strokes it warns of involves managing cardiovascular risk factors:

• Controlling high blood pressure
• Managing cholesterol and diabetes
• Not smoking
• Treating carotid artery disease and irregular heart rhythms
• Taking prescribed blood-thinning or antiplatelet medications
• Having regular checkups, especially after a transient episode of vision loss

When to See a Doctor

Seek emergency care immediately for sudden, painless loss of vision in one eye. Retinal artery occlusion is an eye stroke, and like a brain stroke it requires urgent treatment and evaluation.

• Call emergency services if vision loss occurs with facial drooping, arm weakness, slurred speech, or sudden severe headache.
• Get urgent care for brief episodes of temporary vision loss, which can warn of a coming occlusion or stroke.
• Tell the medical team if you also have new scalp tenderness, jaw pain when chewing, or headaches, which can point to giant cell arteritis.

Related Topics

Frequently Asked Questions

References

1. American Academy of Ophthalmology. Central Retinal Artery Occlusion.
2. American Stroke Association. Retinal artery occlusion and stroke risk.
3. MedlinePlus, U.S. National Library of Medicine. Retinal artery occlusion.
4. National Eye Institute (NEI). Retinal Diseases.