Dynamic Range of Luminance Perception in Acute Hypobaric Hypoxia

Rizzi, Alessandro, Alice Plutino, Diego Vecchi, Anton Giulio Guadagno, and Marco Lucertini. Dynamic range of luminance perception in acute hypobaric hypoxia. High Alt Med Biol. 23:313-318, 2022.-The effects of acute hypobaric hypoxia, as potentially experienced in high altitude flight, on the detection of low contrast targets within a high dynamic range (DR) of luminance were investigated. The tests were performed after 10 minutes of adaptation to an ambient luminance level of 0.2 lx. Twenty-four individuals were exposed to hypobaric hypoxia at an altitude of 18,000 ft (5,490 m) inside a hypobaric chamber and were asked to identify the darkest one perceived from a grid of progressively less luminous patches. The results were compared with those obtained by the same subjects at sea level. The results indicate a global reduction of the DR perception during hypoxia, with a mean decrease of 0.023 cd/m² (standard deviation ±0.064), which resulted statistically significant (p < 0.05). No significant correlations with oxygen saturation levels were observed. These findings might have practical applications in the design of cockpit's instruments, especially those dedicated to night-time flight missions at high altitudes.