Amaurosis

Amaurosis (from greek for darkening, dark or obscure) is a weakness or loss of vision, the cause of which was at one time unknown. It can result from either a medical condition of from excess acceleration, as in flight.

Amaurosis fugax (fugax from the greek for fugitive, amaurosis fugax a is fleeting loss of vision) is a temporary loss of vision in one eye caused by decreased blood flow (ischemia) to the retina. It is a type of transient ischaemic attack (TIA). The lack of blood flow can be caused by emboli (moving clots) obstructing blood flow in the retinal artery/ophthalmic artery. The most common causes are a clot of plaque or a blood clot from a stenosed carotid artery, other sources are heart or heart valves and arterial spasm. Vision loss lasts for the period of time the clot obstructs blood flow.

The experience of amaurosis fugax is described as a "curtain coming down vertically into the field of vision in one eye". Complete blackness (vision loss) in that eye lasts between 5 and 30 minutes.

Even though the blindness is temporary, this is a serious symptom because it indicates the danger of further vascular events occurring, including stroke. Anyone with amaurosis fugax should consult a doctor immediately.