After weeks of typing and coming across no new interesting words, this came up yesterday:
Amaurosis fugax: A symptom described as a shade coming down over the eye; a temporary loss of eyesight can be a partial loss of sight or a complete loss of sight.
This temporary interference with vision is usually related to atherosclerosis in the blood vessels that supply the brain. It can also occur with excessive acceleration, as in flight.
Background: amaurosis is the Greek word for darkening, dark, or obscure. The ancients used it to refer to dimmed vision, especially if there was nothing they could see that was wrong with the eye itself. Fugax is related to fugitive (fleeing). Amaurosis fugax therefore means a fleeting loss of vision.