Effects of hypoxia on the luminance threshold for target detection.

A technique is described--for determining luminance thresholds for detection of realistic target objects--which is suitable for use in simulators and environmental chambers. Data obtained by this technique during a 10-d exposure to high altitude indicate impairments of target detection in direct relation to target viewing distance, absolute target size, and length of hypoxia exposure. In general, impairments reached their maximum during the second day of exposure and recovered gradually thereafter. Wide differences among individual observers were noted. Implications of the results are discussed.