red-outn.
/ˈrɛdaʊt/, U.S. /ˈrɛdaʊt/ 1. Temporary red vision (erythropsia), or obscuring of vision as if by a red curtain, sometimes accompanied by headache or loss of consciousness, experienced when a person is subjected to high negative g-forces, as in an inverted flight manoeuvre, and attributed to congestion of blood in the head; an instance of this. Cf. blackout n. 2a, greyout n., and earlier redding out n.
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the world > health and disease > ill health > a disease > disorders of eye > disordered vision > [noun] > blindness > temporary blindness
teichopsia1872
blackout1929
red-out1942
1942 Richmond (Va.) Times-Dispatch 21 Dec. 13/1 The doctors learn airplane ambulance work... They learn about grayouts, blackouts and redouts.
1943 Effects of Flight (U.S. Navy Training Div., Bur. Aeronaut.) iv. 70 High numbers of g's acting upward through the vertical axis of the body can be produced..and when these are excessive there may be the sensation of everything turning red, followed by unconsciousness. This has been called ‘red-out’.
1962 F. I. Ordway et al. Basic Astronautics xii. 463 If the acceleration is applied in the opposite direction, then a condition known as red-out occurs... The blood..increases in weight to the point where the heart can no longer pump it.
1970 Daily Tel. 10 July (Colour Suppl.) 25/2 With a severe bout of negative G you get a red-out, when so many vessels burst that your vision becomes crimson and you see through a haze of blood.
2007 Globe & Mail (Toronto) (Nexis) 18 July t1 Specialists will test their ability to withstand G-force pressures, which can cause blackouts and even redouts, in which capillaries in the eyes burst.
2. Medicine and Surgery. The obscuring of the view through an endoscope by contact of its tip with blood or tissue; an instance of this.
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1988 Urology 31 383/1 ‘Red outs’ are an occasional problem causing complete loss of visualization on the monitor. This occurs when large amounts of bleeding come from an indeterminate number of vessels all at once.
1996 M. S. Leib in S. L. Jensen et al. Essent. Exper. Surg.: Gastroenterol. x. 7/1 Once the endoscope contacts the mucosal surface, loss of visualization or a ‘red-out’ occurs.
2007 Gastrointestinal Endoscopy 66 1233/1 Often there is little or no space between the tip of the endoscope and the esophageal mucosa wall, leading to ‘red out’ that impairs visual guidance of the injection needle.
This entry has been updated (OED Third Edition, September 2009; most recently modified version published online March 2022).
red-outv.
/ˈrɛdaʊt/, U.S. /ˈrɛdaʊt/ intransitive. To undergo or experience a red-out (red-out n. 1). Cf. to black out at black v. Phrasal verbs, to grey out at grey v. Phrasal verbs.
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1955 M. Reifer Dict. New Words 175 Red out, to experience a red field of vision, congestion of the face and, in particular, the eyes, pressure in the head, etc., as a result of blood rushing to the head in certain aerial maneuvers, such as a rapid climb, inverted spins, outside loops, etc.
1980 Verbatim Winter 19/1 A pilot is in danger of redding out when an aerial maneuver puts a strong positive-G stress on his body.
1994 S. Wicker in D. S. Parker To win Winter Sky xix. 359 I saw tracers passing in front of my nose so I shoved the stick forward and kicked bottom rudder, doing what I think was an inverted vertical reversement. I redded out with a terrific headache.
2004 D. Brown Plan of Attack i. 48 Blood rushed to his head, causing his vision to ‘red out’, and he thought for sure he was going to lose his lunch.
This entry has been updated (OED Third Edition, September 2009; most recently modified version published online March 2022).
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n.1942
v.1955