title: Intersaccadic drift velocity is sensitive to short-term hypobaric hypoxia.
abstract: Hypoxia, defined as decreased availability of oxygen in the body's tissues, can lead to dyspnea, rapid pulse, syncope, visual dysfunction, mental disturbances such as delirium or euphoria, and even death. It is considered to be one of the most serious hazards during flight. Thus, early and objective detection of the physiological effects of hypoxia is critical to prevent catastrophes in civil and military aviation. The few studies that have addressed the effects of hypoxia on objective oculomotor metrics have had inconsistent results, however. Thus, the question of whether hypoxia modulates eye movement behavior remains open. Here we examined the effects of short-term hypobaric hypoxia on the velocity of saccadic eye movements and intersaccadic drift of Spanish Air Force pilots and flight engineers, compared with a control group that did not experience hypoxia. Saccadic velocity decreased with time-on-duty in both groups, in correlation with subjective fatigue. Intersaccadic drift velocity increased in the hypoxia group only, suggesting that acute hypoxia diminishes eye stability, independently of fatigue. Our results suggest that intersaccadic drift velocity could serve as a biomarker of acute hypoxia. These findings may also contribute to our understanding of the relationship between hypoxia episodes and central nervous system impairments.
authors.forename: Leandro L
authors.initials: LL
authors.lastname: Di Stasi
authors.forename: Raúl
authors.initials: R
authors.lastname: Cabestrero
authors.forename: Michael B
authors.initials: MB
authors.lastname: McCamy
authors.forename: Francisco
authors.initials: F
authors.lastname: Ríos
authors.forename: Andrés
authors.initials: A
authors.lastname: Catena
authors.forename: Pilar
authors.initials: P
authors.lastname: Quirós
authors.forename: Jose A
authors.initials: JA
authors.lastname: Lopez
authors.forename: Carolina
authors.initials: C
authors.lastname: Saez
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Macknik
authors.forename: Susana
authors.initials: S
authors.lastname: Martinez-Conde
mesh_terms: D000328:Adult; D000401:Aircraft; D001274:Atmospheric Pressure; D016022:Case-Control Studies; D005221:Fatigue; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D012438:Saccades