Amaurosis Fugax

What is amaurosis fugax?

Amaurosis fugax is a sudden, temporary, and painless episode of blindness. It occurs when blood circulation to the retina is briefly interrupted. It can affect just one or both eyes. But it more commonly occurs in one eye. If it involves both eyes, the differential diagnosis should include other neurovascular causes. The severity ranges from a partial to a total blackout of sight.  

The condition is one of transient visual loss that is also known as:

• Transient monocular visual loss 
• Temporary monocular blindness
• Transient binocular vision loss

The triggers for these episodes range from minor issues to warning signs of stroke. However, any abrupt loss of sight is a medical emergency. Immediate clinical assessment is vital for identifying underlying conditions.

What are the symptoms of amaurosis fugax?

Your vision may suddenly become foggy, blurred, or dim in one or both eyes, as if a curtain is descending over your field of vision from above or from one side. Vision loss may be partial or complete and typically lasts only briefly.

What are the causes of amaurosis fugax?

The primary driver behind amaurosis fugax is sudden retinal ischemia due to occlusion of a retinal blood vessel, which may be caused by:

• Vascular emboli, carotid artery dissection, or atherosclerosis
• Vasospasm, retinal migraine
• Other medical conditions 
  
  • Stroke or transient ischemic attacks (TIAs)
  • Autoimmune & inflammatory disorders: giant cell arteritis
  • Hypoperfusion or hyperviscosity

What factors increase the risk of amaurosis fugax?

• Heart disease
• High cholesterol
• Hypertension
• Carotid artery stenosis
• Diabetes 
• Old age: Individuals aged 50 and older are at increased risk for vascular events.
• History of TIAs
• Smoking, heavy alcohol consumption, and certain substances like cocaine significantly strain the circulatory system.

What are the associated conditions of amaurosis fugax?

• Ischemic stroke
• Myocardial infarction
• Systemic vascular failure

What are the diagnostic approaches for amaurosis fugax?

• Physical examination: A thorough checkup to assess overall health and neurological function.
• Blood chemistry: This includes a Complete Blood Count (CBC), blood glucose levels to rule out diabetes, and coagulation profiles to see how quickly your blood clots.
• Inflammatory markers: Tests such as C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR) help detect systemic inflammation.
• Doppler ultrasound
• MRI or CT scans to look for signs of stroke or structural issues in the brain and its blood vessels
• Electrocardiogram (ECG/EKG): To check the electrical activity and rhythm of the heart
• Holter Monitor: A 24-hour ambulatory electrocardiogram recorder that continuously tracks heart rhythm and can detect arrhythmias that may not appear on a standard ECG.

What are the treatment modalities for amaurosis fugax?

• Emergency intervention

  If the underlying cause is an acute Ischemic Stroke or a Transient Ischemic Attack (TIA), treatment may involve thrombolytic therapy and blood thinners.

• Treating underlying conditions

• Giant cell arteritis (GCA)
  

  This requires high-dose corticosteroids (like Prednisone) immediately to reduce inflammation in the arteries and prevent permanent blindness.

What preventive measures exist for amaurosis fugax?

Prevention focuses on controlling blood pressure, cholesterol, and blood sugar, along with healthy lifestyle changes.

• Keep your blood pressure under control (often below 120/80 mmHg or 130/80 mmHg). High blood pressure is a leading cause of arterial damage and blockages. 
• Manage your cholesterol. Reducing "bad" LDL cholesterol prevents the buildup of fatty plaques in your carotid arteries.
• Maintain stable blood sugar levels to prevent your ocular small blood vessels from becoming brittle or blocked.
• Adopt a vascular-friendly diet, such as the Mediterranean diet, plant-based foods, whole grains, and healthy fats like olive oil. Consume salmon or mackerel twice a week to tamp down vascular inflammation. Avoid processed foods and lower your sodium intake.
• Quit smoking. Smoking is one of the risk factors for atherosclerosis (hardening of the arteries). 
• Aim for at least 30 minutes of brisk walking daily to enhance circulation and strengthen the heart.
• Maintaining a healthy weight.
• Limit alcohol consumption to avoid spikes in blood pressure and heart rhythm irregularities.
• Have an annual eye exam, which can help catch arterial narrowing before it causes a blackout.
• Follow the medication schedule prescribed by your cardiologist, especially for blood thinners or statins.

Essential questions for your medical team

Preparing questions in advance can help patients gain a clearer understanding of their condition, underlying causes, and available treatment options. The following questions may be helpful:

• Is this episode a symptom of a more severe cardiovascular or neurological issue?
• What specific symptoms should trigger an immediate call to emergency services?
• Which therapeutic approach is suitable and safest for me?
• What is a short-term and long-term treatment plan?
• Should I undergo blood tests or imaging tests?
• What side effects or adverse reactions should I take notice of with the prescribed medications?

A note from MedPark's doctors

A brief episode of dimmed vision or the sensation of a dark veil covering your sight may be an early warning sign of a serious vascular condition. Even if your vision returns to normal within seconds, it should never be ignored.

Sudden vision loss—whether painful or not—is considered a medical emergency and requires immediate evaluation.

Early assessment allows doctors to identify the source of the blockage before permanent damage occurs. Prompt diagnosis also plays a critical role in reducing the risk of future events, such as stroke or major cardiac complications.