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A sudden reddening of the visual field accompanied by severe headache and caused by engorgement of the blood vessels of the head when a person is subjected to a negative force of gravity, as in stunt flying.
reddened vision and other symptoms caused by a rush of blood to the head in response to negative gravitational stresses
a condition experienced by pilots and astronauts in which rapid deceleration or a negative gravity force drives blood to the head, reddening the field of vision.
[1940–45; on the model of blackout]