Ocular Ischemic Syndrome

People with carotid artery disease are at risk of developing a rare eye condition called ocular ischemic syndrome. A buildup of plaque in a carotid artery slows blood flow to your eyes. You may experience vision issues and eye pain. Carotid artery disease treatments can protect your vision and lower your risk of stroke.


What is ocular ischemic syndrome?

Ocular ischemic syndrome is a rare eye condition. It occurs when there’s a lack of blood flow to your eyes due to plaque building up in a carotid artery in your neck. Plaque buildup restricts blood flow to one or both eyes, causing vision issues and eye pain. Ocular ischemic syndrome can also be the first sign of carotid artery disease. This condition increases your risk of strokes and heart attacks.

To understand this condition better, it may help to break down the meaning of each word:

  • Ocular” is the medical term for eyes.
  • Ischemic,” or ischemia, refers to reduced blood flow from atherosclerosis. This is a hardening or narrowing of your arteries. Atherosclerosis can lead to carotid artery disease.
  • Syndrome”means various conditions or symptoms occur together.

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Symptoms and Causes

What causes ocular ischemic syndrome?

Carotid artery disease (also known as carotid artery stenosis) causes ocular ischemic syndrome. “Stenosis” is another way of saying that an artery is too narrow. Your carotid arteries are two blood vessels in your neck. They carry oxygenated blood to organs and tissues in your head and neck, including your brain. With carotid artery disease, plaque deposits (atheroma) of a fatty substance build up in one or both carotid arteries.

Your ophthalmic arteries branch from your carotid arteries. They deliver blood to your eyes. When you have carotid artery disease, blood doesn’t flow to your eyes as it should. This lack of blood flow can lead to ocular ischemic syndrome.

Less common causes of ocular ischemic syndrome include:

Who is at risk?

Ocular ischemic syndrome is extremely rare. It affects approximately 8 in 1 million people.

It tends to affect people in their 50s to 80s. It’s twice as common in men and people assigned male at birth (AMAB).

Risk factors for ocular ischemic syndrome include:

What are ocular ischemic syndrome symptoms?

Ocular ischemic syndrome doesn’t always cause symptoms. When symptoms occur, they’re most likely to affect only one eye. The condition affects your vision, causing:

  • Dull, aching eye pain that comes and goes.
  • Eye pain in the setting of increased pressure in your eye.
  • Enlarged or dilated pupils (black circle in the center of each eye).
  • Eye floaters.
  • Gradual or sudden vision loss (low vision) or transient vision loss.
  • Light sensitivity (photophobia).
  • Double vision (diplopia).

Diagnosis and Tests

How do healthcare providers diagnose ocular ischemic syndrome?

Ocular ischemic syndrome causes symptoms similar to other conditions. These include diabetes-related retinopathy and central retinal vein occlusion (CRVO). An accurate diagnosis is key to proper treatment.

Eye care specialists such as ophthalmologists diagnose ocular ischemic syndrome using these tests:

  • Eye exams to identify the cause of vision problems. These may include a dilated eye exam, optical coherence tomography (OCT), electroretinography and visual-evoked potentials.
  • Fluorescein angiogram to check for the time it takes for blood to reach your eye and leakage in blood vessels in your eyes.

A cardiologist is a cardiovascular (heart and blood vessel) specialist. They may order these tests to check for carotid artery disease:

Management and Treatment

How is ocular ischemic syndrome treated?

The treatment of ocular ischemic syndrome involves multiple care steps from different specialists.

Treatments for ocular (eye) problems include:

  • Eye injections of anti-vascular endothelial growth factor (anti-VEGF) drugs or steroids. These can help treat swelling in your retina.
  • Medicated eye drops to lower eye (intraocular) pressure and inflammation.
  • You may also need laser treatment in your eye to prevent high eye pressure.

Treatments for carotid artery disease include:


What are the complications?

Ocular ischemic syndrome doesn’t always cause immediate eyesight problems. However, up to half of the people with this condition will eventually experience some degree of vision loss within a year. Nearly 7 in 10 people will develop neovascular glaucoma. In neovascular glaucoma, because there isn’t enough blood flow to your eye, abnormal blood vessels grow and block the drainage system of your eye causing dangerously high eye pressure.


Can you prevent ocular ischemic syndrome?

You can make certain lifestyle changes to lower your risk of carotid artery disease and ocular ischemic syndrome. These steps include:

  • Eating a heart-healthy diet like the Mediterranean diet.
  • Finding healthy ways to cope with stress.
  • Keeping diabetes and high blood pressure under control.
  • Maintaining a weight that’s healthy for you.
  • Seeking help to quit smoking.
  • Staying physically active.

Outlook / Prognosis

What’s the outlook for someone with ocular ischemic syndrome?

The carotid artery disease that causes ocular ischemic syndrome can be life-threatening. As many as 4 in 10 people die from a heart attack or stroke within five years after receiving an ocular ischemic syndrome diagnosis. Prompt medical care and lifestyle changes can help protect your health.

Living With

When should I call my healthcare provider?

You should call your healthcare provider if you experience:

  • Eye pain.
  • Vision problems.

If you experience any signs of a stroke, call 911 immediately. Look for slurred speech, one-sided weakness or facial drooping.

What should I ask my provider?

You may want to ask your healthcare provider:

  • What’s causing my symptoms?
  • What diagnostic tests do I need?
  • What’s the best treatment for me?
  • How can I improve my heart health?
  • What steps can I take to protect my vision?
  • Should I look for signs of complications?

A note from Cleveland Clinic

Any condition that affects your eyes is deeply concerning. If you have ocular ischemic syndrome, vision changes may be the first indication that your blood vessels are narrowing and restricting blood flow to your head. This can be a symptom of other conditions, including carotid artery disease. Other eye conditions can also cause similar symptoms.

It’s important to see an eye specialist with experience diagnosing and treating rare eye diseases. You’ll also see a cardiovascular specialist to treat carotid artery disease. These treatments open a narrowed artery to improve blood flow to your eyes. You can also make lifestyle changes to protect your heart and vision.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 08/18/2023.

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