What Is Amaurosis Fugax? How Do You Treat It?
Key takeaways:
Amaurosis fugax is a temporary loss of vision in one or both of the eyes caused by decreased blood flow to the eye.
Blood clots, plaque inside the blood vessels leading to the eye, or a sudden drop in blood pressure can all cause amaurosis fugax.
The treatment for amaurosis fugax depends on the cause. Some people might need anticoagulant or antiplatelet medications, while others might need surgery on their carotid arteries to remove plaque.
Amaurosis fugax is a temporary loss of vision in one or both eyes. It can last anywhere from a few minutes to half an hour.
Amaurosis fugax isn’t actually a disease itself. Instead, it’s a symptom that can be caused by several different medical conditions. But they all have one thing in common: They’re conditions that can lead to decreased blood flow to the eye.
Amaurosis fugax is a potentially serious symptom that you shouldn’t ignore. Read on to find out more about what causes amaurosis fugax and what you can do about it.
What are the symptoms of amaurosis fugax?
The primary symptom of amaurosis fugax is a painless change in vision in one or both eyes. Vision changes can vary from person to person. Some people experience complete vision loss while others only notice partial vision loss.
Most people notice a darkening of their vision. It can look like a curtain coming down across their vision or like there are shadows over their vision. Other people feel like their vision looks darker overall as they’re trying to see in dim light or in the dark.
These vision changes are temporary and can last several minutes to several hours. Symptoms of amaurosis fugax overlap with other eye conditions like retinal tears and retinal detachment, which can lead to permanent vision loss if not treated right away.
That’s why it’s so important to see an eye doctor right away if you experience sudden vision changes. It’s impossible to tell if your symptoms are temporary from conditions like amaurosis fugax or if they’re due to vision-threatening eye conditions.
What causes amaurosis fugax?
Amaurosis fugax is usually caused by a temporarily reduced blood flow to one or both of the eyes. This is caused by conditions that affect the blood vessels that bring blood to the brain and eyes. When that blood flow decreases, the retina can’t function very well. This makes someone’s vision go dark.
Conditions that can cause reduced blood flow include:
Atherosclerosis: This is a condition in which plaques build up on the insides of blood vessels over time. These plaques can narrow the blood vessels — or even completely block them. This often occurs in the carotid arteries, which are the large arteries in the neck that carry blood from the heart up to the brain. The eyes rely on this blood supply, too.
Blood clots: If a blood clot forms in the heart or an artery, it can break off, travel downstream, and then block the more narrow arteries near the eye. These blood clots could form in the carotid arteries, especially if they have plaque. People who have a heart condition called atrial fibrillation can also develop blood clots inside the heart that can travel to these arteries.
Low blood pressure: Anything that lowers the blood pressure throughout the whole body can affect the blood flow to the eyes. This can happen with conditions like orthostatic hypotension, when the blood pressure drops because of a change in position. Or it could come from a sharp drop in blood pressure from medications or severe dehydration. Amaurosis fugax is more likely to happen in these situations when the blood vessels in the neck and brain are already narrowed for some other reason.
Amaurosis fugax can also develop when there’s damage to the optic nerve, which connects the eye to the brain. Conditions like multiple sclerosis can cause optic nerve damage and amaurosis fugax.
How do you diagnose amaurosis fugax?
There isn’t a specific test that diagnoses amaurosis fugax, given it’s actually a symptom of other medical conditions. There are still some tests you might need if you’re having symptoms that are worrisome for amaurosis fugax. These include:
A fundoscopic exam: This is a way your healthcare provider can get a good look at your retina in the back of the eye. They use a special light to do it, but it will essentially feel like a normal eye light exam. This allows them to look for signs of blood clots in the retina.
Imaging of the carotid arteries: You might need an ultrasound or a CT scan of the carotid arteries to check for atherosclerosis. These tests could also show anything else that may be affecting blood flow in these arteries.
Imaging of the brain: Most people will get imaging studies to look at the brain, such as a CT scan or an MRI. They can also look for other parts of the brain that may be affected by lack of blood flow.
How do you treat amaurosis fugax?
Amaurosis fugax is a temporary symptom. So the treatment is aimed at preventing future episodes. If your amaurosis fugax is being caused by decreased blood flow, you’ll need treatment to address blood vessel disease, plaque, or blood clots that caused the episode in the first place.
Treatment usually involves medications. But sometimes it might need surgery. Some examples of treatment are:
Antiplatelet medications
Platelets are cells in the blood that help it clot. Medications that lower the ability of the platelets to form clots can prevent blood clots from forming at the site of atherosclerosis. Examples of antiplatelet medications include aspirin or clopidogrel (Plavix).
Anticoagulant medication
Commonly called blood thinners, these medications also block the blood’s ability to form clots. These include medications like warfarin (Coumadin), apixaban (Eliquis), and rivaroxaban (Xarelto).
Carotid artery stenting
This is a procedure where a healthcare provider puts a small metal tube in the carotid artery to prop it open and improve blood flow. This can help in areas where plaque has narrowed the blood vessel.
Carotid endarterectomy
This is a surgical procedure. A vascular surgeon will open up the carotid artery and remove the plaque inside it that’s blocking blood flow.
How can I prevent amaurosis fugax?
It’s important to know what conditions put you at risk of atherosclerotic disease and blood clots. Preventing progression of these conditions will also prevent episodes of amaurosis fugax. These conditions include:
Atrial fibrillation: Many people with atrial fibrillation will take an anticoagulant. This is to prevent blood clots from forming in the heart.
Diabetes: Having high blood sugar for a long time can damage blood vessels and lead to atherosclerosis. Along with medications, exercising, and changing your diet can also help prevent these issues.
High blood pressure: Over time, high blood pressure leads to blood vessel damage and atherosclerosis. Lifestyle changes — often along with blood pressure medications — can help with this.
High cholesterol: Cholesterol is a major part of the plaques that form in arteries. Treating high cholesterol with medications can prevent atherosclerosis. High cholesterol can also improve with changes to your diet.
Smoking: This is a common cause of atherosclerosis. If you smoke, think about cutting back or quitting.
The bottom line
Amaurosis fugax is a serious condition. It helps to think of it as a temporary stroke that affects the eye. It’s usually a sign of underlying heart or blood vessel disease. If not treated, these conditions could lead to permanent vision loss or a stroke. If one of these episodes happens to you, don’t wait to get medical help. This is true even if your vision returns to normal. This way, you can get treatment for any serious medical conditions before they progress.
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References
MedlinePlus. (2022). Amaurosis fugax.
Tadi, P., et al. (2023). Amaurosis fugax. StatPearls.
