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.

Effect of professional expertise and exposure to everyday life decision-making on moral choices.

Moral sense is defined as a feeling of fairness or unfairness of an action that knowingly causes harm to people other than the subject. It is crucial in determining human behavior and becomes pivotal in operational environments. Here we assessed whether professional daily life experience in an operational environment affects moral judgment by asking 41 military pilots of the Italian Air Force (P) and 69 controls (C) to solve 40 moral dilemmas. We found that P gave more morally acceptable utilitarian responses to moral dilemmas. Interestingly, men and women in P equally accepted utilitarian resolutions of moral dilemmas, whereas in C women were less prone than men to accept utilitarian responses. We conclude that professional daily life experience of P, in an operational environment, affects moral judgment and mitigates gender predisposition towards moral dilemmas.

Visual function at altitude under night vision assisted conditions.

INTRODUCTION: Hypoxia, even mild, is known to produce negative effects on visual function, including decreased visual acuity and sensitivity to contrast, mostly in low light. This is of special concern when night vision devices (NVDs) are used during flight because they also provide poor images in terms of resolution and contrast. METHODS: While wearing NVDs in low light conditions, 16 healthy male aviators were exposed to a simulated altitude of 12,500 ft in a hypobaric chamber. RESULTS: Snellen visual acuity decreased in normal light from 28.5 +/- 4.2/20 (normoxia) to 37.2 +/- 7.4/20 (hypoxia) and, in low light, from 33.8 +/- 6.1/20 (normoxia) to 42.2 +/- 8.4/20 (hypoxia), both at a significant level. An association was found between blood oxygen saturation and visual acuity without significance. No changes occurred in terms of sensitivity to contrast. DISCUSSION: Our data demonstrate that mild hypoxia is capable of affecting visual acuity and the photopic/high mesopic range of NVD-aided vision. This may be due to several reasons, including the sensitivity to hypoxia of photoreceptors and other retinal cells. Contrast sensitivity is possibly preserved under NVD-aided vision due to its dependency on the goggles' gain.