AMAUROSIS FUGAX

Definition

The word ''amaurosis'' comes from Greek language which means to 'darken or obscured'

The word 'fugax' means 'fleeing'. Its a sudden, temporary, partial or total loss of vision from any cause.

Aetiology

Circulatory

Embolic Hypoperfusion Carotid & Cardiac emboli Artherosclerotic carotid artery

Occular

Keratitis Angiospasm

Neurological SLE Optic neuritis Multiple sclerosis

Atherosclerotic carotid artery

Amaurosis fugax may present as a type of transient ishcemic attack (TIA), during which an embolus unilaterally obstructs the lumen of the retinal artery or ophthalmic artery causing a decrease in blood flow to the ipsilateral retina.

Common source of these athero-emboli is an atherosclerotic carotid artery. Severely atherosclerotic carotid artery causes amaurosis fugax due to its stenosis of blood flow, leading to ischemia.

Cardiac Emboli

Thrombotic emboli arising from the heart causes

luminal obstruction of the retinal, ophthalmic, and/or ciliary arteries, causing decreased blood flow to the ipsilateral retina examples being those arising due to (1) atrial

fibrillation, (2) valvular abnormalities including postrheumatic valvular disease, mitral valve prolapse, and a bicuspid aortic valve, and (3) artrial myxomas.

Temporary Vasospasm

leads to decreased blood flow that can cause amaurosis fugax. Generally, these episodes last no longer that five minutes, and have been associated with exercise

Observations suggest that a systemic hemodynamic challenge provoke[s] the release of vasospastic substance in the rentinal vasculature of one eye."

Symptoms

Transient monocular vision loss that appears as a "curtain'' coming down vertically into the field vision in one eye;" however, this altitudinal visual loss is relatively uncommon.

Others includes a monocular blindness, dimming, fogging, or blurring. Total or sectorial typically lasts only a few seconds, but may last minutes or even hours. Duration depends on the etiology of the vision loss.

Sign and Tests

complete eye and neurological exam. In some cases, an eye exam will reveal a bright spot where the clot is blocking the retinal artery.

A carotid ultrasound or magnetic resonance angiography (MRA) scan should be done to evaluate a blockage in the carotid artery.

Routine blood tests such as cholesterol and blood sugar should be done to check your risk for atherosclerosis, which increases with high cholesterol and diabetes.

Treatments

directed therapies to treat that underlying etiology should be initiated

If the amaurosis fugax is caused by an atherosclerotic lesion, aspirin is indicated, and a cardiac endarterectomy if the stenosis is surgically accessible

Central Retinal Artery Occlusion

Branch Retinal Artery Occlusion

Brach Retinal Vein Occlusion