red-out

'red-out'

 A homogeneous red-orange color seen by GI endoscopy when the intestinal mucosa directly covers the endoscope's lens, allowing only the passage of light across the blood vessel-rich mucosa; red-out can be corrected by a puff of air to push the mucosa away from the visual field.

red-out

(rĕd′owt)
A term used in aerospace medicine to describe what happens to the vision and central nervous system (i.e., seeing red and perhaps experiencing unconsciousness) when the aircraft is doing part or all of an outside loop at high speed, or any other maneuver that causes the pilot to experience a negative force of gravity. The condition is due to engorgement of the vessels of the head including those of the retina.