Amaurosis Fugax

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Amaurosis fugax is a temporary loss of vision in one eye due to a lack of blood flow to the retina, often described as a "curtain" or "shade" coming down over the eye. It typically lasts for a few seconds to minutes.

Aetiology

Amaurosis fugax can be caused by various factors, including:

• Emboli from the carotid arteries or heart
• Thromboembolic events
• Vasospasm
• Giant cell arteritis
• Severe hypotension
• Cardiac arrhythmias

Pathophysiology

The transient loss of vision in amaurosis fugax is typically due to a temporary reduction or cessation of blood flow to the retina. This can result from emboli or thrombi obstructing the retinal arteries, vasospasm, or other vascular events that reduce perfusion to the retinal tissue.

Risk Factors

• Atherosclerosis
• Hypertension
• Diabetes mellitus
• Hyperlipidaemia
• Smoking
• Cardiovascular diseases
• History of transient ischaemic attacks (TIAs) or stroke
• Giant cell arteritis (especially in older adults)

Signs and Symptoms

Common signs and symptoms of amaurosis fugax include:

• Sudden, painless loss of vision in one eye
• Vision loss described as a "curtain" or "shade" descending over the eye
• Vision typically returns to normal within minutes

Investigations

• Clinical history and physical examination
• Carotid ultrasonography to assess for carotid artery disease
• Echocardiography to identify cardiac sources of emboli
• Blood tests to check for hyperlipidaemia, diabetes, and inflammatory markers
• Magnetic resonance imaging (MRI) or computed tomography (CT) of the brain to rule out stroke
• Electrocardiography (ECG) to detect cardiac arrhythmias
• Temporal artery biopsy if giant cell arteritis is suspected

Management

Primary Care Management

• Immediate referral to an ophthalmologist or neurologist: For further evaluation and management
• Management of underlying conditions: Such as controlling blood sugar levels in diabetes or blood pressure in hypertension
• Aspirin: To reduce the risk of thromboembolic events (e.g., 75-150 mg daily)

Specialist Management

• Treatment of the underlying cause:
  • Carotid endarterectomy or stenting for significant carotid artery stenosis
  • Anticoagulation therapy for cardiac sources of emboli (e.g., atrial fibrillation)
  • High-dose corticosteroids for giant cell arteritis (e.g., prednisolone)
• Lifestyle modifications: Smoking cessation, diet, and exercise to reduce cardiovascular risk factors
• Regular follow-up to monitor and manage risk factors

References

1. NICE. (2024). Amaurosis Fugax: Diagnosis and Management. Retrieved from NICE
2. NHS. (2023). Amaurosis Fugax. Retrieved from NHS
3. British Medical Journal (BMJ). (2022). Amaurosis Fugax: Diagnosis and Management. Retrieved from BMJ
4. American Academy of Ophthalmology (AAO). (2021). Clinical Practice Guidelines: Amaurosis Fugax. Retrieved from AAO

Back to Top