“Dr. is a kind, and patient Dr. Nice to see in younger generation. Back staff girls funny & kind. Reception kind too. Thank you for a good experience!”
Amaurosis Fugax: When a Curtain Crosses Your Vision in One Eye
Why You Must Go to the Emergency Room Today
A temporary episode of vision loss in one eye needs to be evaluated in an emergency department, not a scheduled clinic visit. The risk of a stroke is highest in the hours and days immediately following this kind of event, and the tests required cannot be completed in a standard eye office.
Do not drive yourself and do not wait to see if things improve. Call 911 immediately if any of the following are present.
- Vision is still lost, or it is dim and not fully recovered
- One side of the face is drooping
- One arm feels weak or numb
- Speech is slurred or words are difficult to find
- There is sudden dizziness or difficulty walking
- A new severe headache has developed
- There is tenderness in the scalp or an ache in the jaw while chewing
These symptoms together or separately indicate a possible stroke that requires immediate emergency response.
Go to the nearest emergency room affiliated with a stroke center, even if your vision has come back entirely. Studies estimate that people who experience this type of event and go untreated carry roughly a 10 to 15 in 100 risk of stroke within the first year, and more than half of those strokes occur within the first 48 to 72 hours of the warning episode. That narrow window is exactly why same-day evaluation matters.
Expect a stroke workup, not a standard eye examination. The emergency team will perform cardiac monitoring, blood tests, an electrocardiogram (EKG), brain imaging, and imaging of the blood vessels in the head and neck. A stroke neurologist is typically consulted, and a retina specialist may examine your eye as part of the evaluation. The goal is to identify the source of the blockage and begin treatment before a larger event occurs.
What Causes Temporary Vision Loss in One Eye
Several different conditions can produce this symptom, and identifying the correct cause directs which treatment is used. The most common sources involve the blood vessels supplying the eye and brain, but other causes exist and are also evaluated during the workup.
This is the most common cause and the one the medical team looks for first. Fatty deposits (called atherosclerotic plaque) build up at the point where the carotid artery in the neck divides into two branches. Small fragments can break away from that plaque and travel into the retinal circulation, where they block the blood flow briefly before moving on.
Risk factors for carotid plaque include diabetes, high blood pressure, high cholesterol, heart disease, smoking, and older age. Each of those risk factors is something a treatment plan can address.
In some cases the clot begins in the heart rather than in the neck. Atrial fibrillation, an irregular heart rhythm that allows blood to pool and form clots, is one cardiac source. Valvular heart disease is another. Atrial fibrillation often produces no noticeable symptoms, which is why an EKG and sometimes a longer-term heart monitor are ordered even when a patient feels no heart irregularity. Identifying this source changes the type of blood-thinning medicine that is recommended.
Not every episode stems from a clot or plaque. Giant cell arteritis is an inflammation of medium and large blood vessels that can restrict blood flow to the eye and should be considered in anyone older than 60 who experiences repeated episodes. New headache, scalp tenderness, or jaw pain while chewing are symptoms that raise this concern and should be reported to the medical team immediately.
Other causes include spasm of a blood vessel, retinal migraine, and problems within the eye itself such as increased pressure or swelling of the optic nerve. Distinguishing between these causes requires a clinical examination and testing, not a checklist of symptoms alone.
How Amaurosis Fugax Is Diagnosed
The diagnostic process combines an eye examination with imaging of the arteries and heart, as well as blood tests. No single test alone is sufficient, and the full picture is usually assembled across several specialties working together.
A retina specialist will perform a dilated eye examination, in which drops widen the pupil to allow a clear view of the retina and its blood vessels. In some cases, small bright cholesterol fragments called Hollenhorst plaques are visible inside a retinal artery. These are direct evidence of the material that caused the blockage. A normal-appearing retina does not rule the episode out, since the fragment often moves on before the examination takes place.
After dilating drops, near vision will be blurry and eyes will be sensitive to light for a few hours. Arrange a ride home from any appointment that involves dilation.
Carotid ultrasound, a painless procedure using gel and a handheld probe on the neck, is the standard first imaging study. It measures how much the carotid artery has narrowed, which directly influences treatment decisions. When the ultrasound result is inconclusive, CT angiography or MR angiography of the head and neck provides additional detail about the vessels.
Brain MRI is also often obtained. Studies have found that brain imaging after this type of event shows silent changes in a meaningful percentage of patients, which is why imaging is performed rather than assumed to be normal.
The cardiac evaluation typically includes an EKG performed the same day, along with Holter monitoring to detect intermittent atrial fibrillation and an echocardiogram (an ultrasound of the heart) to look for valve problems or areas where clots could form. Blood tests cover cholesterol, blood sugar, a complete blood count, clotting function, and inflammatory markers called ESR and CRP. Elevated ESR and CRP can support a diagnosis of giant cell arteritis, which is why these results are needed quickly.
Treatment and Stroke Prevention
Treatment is directed at the underlying cause identified during the workup. The goal is to reduce the risk of a future stroke and to protect the vision in both eyes. Several approaches are used together rather than in isolation.
Antiplatelet medicines such as aspirin or clopidogrel are commonly prescribed when the source of the clot is a vessel in the neck. When the source is the heart, anticoagulant medicines are used instead, with the direct oral anticoagulants generally preferred over warfarin except in cases involving valve disease. A statin medication is typically added to bring LDL cholesterol to a target level, and blood pressure medication is used to reach a target below 130/80 mm Hg.
Specific doses and medicine choices are made based on each patient's individual health history. Do not stop or adjust these medicines without speaking to the prescribing physician first, and ask what each one is for and what side effects to report.
If the carotid ultrasound shows a severe narrowing (called stenosis) on the same side as the affected eye, surgery may be recommended. The procedure is called carotid endarterectomy, in which the artery is opened and the plaque is removed. This operation is generally recommended when the narrowing reaches 70 to 99 percent. Whether surgery is appropriate depends on the exact degree of narrowing, the patient's overall health, and which side is involved. Asking for the specific percentage from the ultrasound report is a reasonable and important question.
Daily habits affect the same plaque buildup that caused the episode. Stopping smoking, controlling blood pressure and blood sugar, lowering cholesterol through diet and medication, and staying physically active all reduce the conditions that allow plaque to form and break apart. These changes do not undo existing buildup overnight, but they directly affect what happens in the years ahead.
Understanding the Risks
Knowing the actual risk numbers helps make sense of why the response to this symptom must be immediate. The risk is real but also treatable, and the emergency evaluation is the step that moves a person from the higher-risk group into the treated group.
Studies estimate that amaurosis fugax left untreated carries roughly a 10 to 15 in 100 risk of stroke within the first year. In a large health-record analysis of adults who experienced a blocked retinal artery or an episode of amaurosis fugax, approximately 14 of every 100 had an ischemic stroke within one year, and approximately 9 of every 100 had a serious vascular event on the same day as the eye episode. The steepest portion of that risk falls within the first 48 to 72 hours, which is precisely the window that emergency evaluation is designed to address.
An episode that clears can be followed by one that does not. When the blockage in the main retinal artery is permanent rather than temporary, the condition is called central retinal artery occlusion, which is itself a form of acute ischemic stroke. The treatment window for this event is narrow, and fewer than 20 of every 100 people recover functional vision in the affected eye. Sudden vision loss that does not clear within a few minutes is a call-911 emergency, not a watch-and-wait situation.
Antiplatelet or anticoagulant medicines, statin therapy, and blood pressure control together reduce the risk that follows this type of event. For patients with severe carotid narrowing who undergo endarterectomy, studies show a meaningful improvement in prognosis, although cardiovascular risk requires ongoing management. No individual outcome can be guaranteed, but the emergency visit and the treatment that follows it are the actions that shift the odds in a patient's favor.
Frequently Asked Questions
These answers address questions that often arise after an episode of amaurosis fugax, including decisions about when to seek care and what to expect from the evaluation process.
Yes, and going today rather than waiting is what matters most. The vision returning tells you only that the clot moved, not that the source of it has resolved. The stroke risk is highest in the first 48 to 72 hours after this kind of warning event, and the full workup, including brain imaging, artery imaging, and cardiac monitoring, cannot be done in an eye clinic. The emergency department connected to a stroke center is the right setting, and getting there the same day is the decision that shortens the highest-risk window.
Migraine is a recognized cause of brief vision disturbance, but it is a diagnosis that should be reached after the vascular causes are excluded, not instead of checking for them. When both eyes are affected, migraine with aura is among the possibilities alongside reduced blood flow in the vessels at the back of the neck. When only one eye is involved, vascular causes are evaluated first, especially in anyone who has risk factors such as high blood pressure, high cholesterol, diabetes, smoking history, or older age. A retina specialist and a stroke neurologist working together are the appropriate people to make that distinction.
A second episode is a new emergency and should be treated exactly like the first one, meaning a return to the emergency department rather than a call to a clinic. Even patients who are already on antiplatelet or anticoagulant medicines can experience another event, and a repeat episode may signal that the treatment plan needs to be adjusted or that the carotid artery has changed. Note which eye was affected, when it started, and how long it lasted before going in, as that information helps the team assess whether the situation has changed.
Knowing your results and understanding the plan helps you manage your risk over time. The most useful questions to ask include what the carotid ultrasound showed and the exact percentage of any narrowing found, whether the narrowing is on the same side as the eye that was affected, whether the heart monitor or echocardiogram identified a source, what the ESR and CRP values were, what each prescribed medicine is for and how long it should be taken, whether carotid surgery is being considered and on what basis that decision would be made, and what specific symptoms should prompt a 911 call versus a scheduled appointment. Ask for copies of imaging reports and blood results in writing to bring to follow-up appointments.
Yes. A retina specialist will typically re-examine the eye after the acute workup to check the health of the retina and optic nerve and to document a baseline for comparison. Ongoing retinal follow-up is important because a person who has had one ischemic eye event remains at elevated risk for future vascular events affecting both the eye and the brain. Coordinating eye care with primary care and any cardiology or vascular surgery follow-up gives the most complete picture of overall vascular health over time.
Sudden vision loss that does not clear within a few minutes, a new dark curtain that stays in place, or any vision loss accompanied by face drooping, arm weakness, slurred speech, or severe headache are all reasons to call 911 immediately. These are not symptoms to monitor at home or report at a routine appointment. A central retinal artery occlusion, in which blood flow to the retina is permanently blocked, has a very narrow treatment window, and the outcome for vision is substantially better when care begins within the first hours. When in doubt, call 911 and let the emergency team assess the situation.
See Our Team at Atlantic Retina Center
Our fellowship-trained, board-certified retina specialists at Atlantic Retina Center are experienced in diagnosing and managing retinal vascular conditions throughout the Eastern Shore of Maryland and central and southern Delaware. We work closely with emergency, neurology, and cardiology teams to ensure that patients who experience warning events receive coordinated, complete care. If you have been referred for a retinal evaluation after a vascular episode, we encourage you to contact us promptly so we can be part of your care team from the start.