“…About 70% of pilots noted that vision occasionally and unintentionally alternated between their left and right eye either during or after flight. Moreover, Rash, Verona, and Crowley (1990) stated that aviators using the IHADSS reported difficulty making the necessary attention switches between the eyes. An additional problem with HWDs is simulator sickness, which can be caused by a number of factors, such as vestibular-visual cue conflict (Draper, Viirre, Furness, & Gawron, 2001;Draper, Viirre, Furness, & Parker, 1997;Ehrlich, 1997).…”