saccade \sa-KAHD\, noun:
1. The movement of the eye when it makes a sudden change, as in reading.

2. The act of checking a horse quickly with a single strong pull of the reins.

He added the bill with a single saccade of his pulsing eyes.
-- Will Self, My Idea of Fun: A Cautionary Tale

I inject a milky white liquid into the IV line and watch my patient's eyes close in a slow, hypnotic saccade.
-- Carol Cassella, Oxygen

Saccade originally refers to horsemanship and begins as the Middle French saquer, "to pull violently."