Transient visual loss (amaurosis fugax)
- Clinical approach
Vision that goes dark in one eye for minutes and comes back is a warning stroke of the eye. It needs the same urgent workup as a transient ischaemic attack.
See it in 3D: Retina · Central retinal artery · Ophthalmic artery
What it is
Transient monocular visual loss, classically a curtain falling over one eye for a few minutes, is most often an embolus from the carotid artery or the heart passing through the retinal circulation. It is a transient ischaemic attack of the retina. Other causes depend on how long it lasts and whether one or both eyes are affected: seconds with posture change in papilloedema, 20 to 30 minutes of shimmering zigzags in both eyes in migraine aura, and giant cell arteritis in older people.
Red flags
- Monocular episode lasting minutes in an adult with vascular risk factors: carotid or cardiac embolism.
- Age over 50 with headache, jaw claudication or scalp tenderness: giant cell arteritis.
- Episodes lasting seconds on standing or bending, with headache: papilloedema (transient visual obscurations).
- Repeated episodes or a visible bright embolus in a retinal artery.
- Any weakness, numbness or speech disturbance at the same time.
Step-by-step approach
- Ask whether one eye or both were affected and whether covering one eye was tried.
- Ask the duration, the pattern (curtain, blur, shimmering lights) and how often it has happened.
- Ask vascular risk factors, palpitations, neurological symptoms and the symptoms of giant cell arteritis.
- Examine visual acuity, pupils and fundus: look for emboli at artery branch points and for disc swelling.
- Listen for a carotid bruit, check the pulse rhythm and measure blood pressure.
Transient visual loss by pattern
| Pattern | Eyes | Think of | Next step |
|---|---|---|---|
| Curtain for 2 to 30 minutes | One | Carotid or cardiac embolism | Same-day stroke workup |
| Episodes with headache, over 50 | One or both | Giant cell arteritis | ESR, CRP and steroids the same day |
| Seconds on standing up | One or both | Papilloedema | Urgent brain imaging |
| Shimmering zigzag spreading over 20 to 30 minutes | Both | Migraine aura | Clinical diagnosis if typical |
| Minutes, both eyes, with dizziness or double vision | Both | Vertebrobasilar ischaemia | Same-day stroke workup |
Keys to the differential
- A bright yellow cholesterol embolus (Hollenhorst plaque) at a retinal artery branch points to the carotid artery.
- Most patients have a normal eye exam by the time they are seen: the history makes the diagnosis.
- Retinal migraine, monocular loss with headache in a young person, is a diagnosis of exclusion.
- Atrial fibrillation is a common cardiac source; an ECG is part of the first evaluation.
Next step / Initial management
- Treat transient monocular visual loss as a transient ischaemic attack: same-day emergency stroke evaluation with brain imaging, carotid imaging (Doppler or angiography), ECG and rhythm monitoring.
- Start secondary prevention through the stroke pathway: antiplatelet therapy, statin and risk-factor control, with carotid surgery if there is significant symptomatic stenosis.
- Over 50 with symptoms of giant cell arteritis: ESR and CRP, start corticosteroids the same day and refer.
- Episodes with headache or swollen discs: urgent brain imaging for raised intracranial pressure.
- Ophthalmology exam to look for emboli and rule out an eye cause.
Test yourself
Think of the answer, then tap the question to see it.
How should a 68-year-old with five minutes of monocular blackout be managed?
As a transient ischaemic attack: same-day stroke workup with brain and carotid imaging, ECG and secondary prevention.
What is a Hollenhorst plaque?
A bright cholesterol embolus seen at a retinal artery branch, usually from an atheromatous carotid artery.
What do visual obscurations lasting seconds on standing suggest?
Papilloedema from raised intracranial pressure; it needs urgent brain imaging.
Connections
See it in 3D3
The structures of Durgical's 3D anatomy where it is found.
Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once.
Sources: Amaurosis Fugax (StatPearls Publishing (NCBI Bookshelf), 2025); Retinal Migraine Headache (StatPearls Publishing (NCBI Bookshelf), 2023); Giant Cell Arteritis (Temporal Arteritis) (StatPearls Publishing (NCBI Bookshelf), 2024).
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Representative model, for educational purposes only.