Oculomotor responses with aviator helmet-mounted displays and their relation to in-flight symptoms

Previous experiments have raised the possibility that abnormal oculomotor functioning could be the substrate for visual problems among aviators who use helmet-mounted displays. However, until the present investigation, no direct evidence linked the two. In our experiments, experienced Apache helicopter pilots, using the same helmet-mounted display that they use in flight, viewed Apache symbology and sensor imagery while we measured their accommodation and vergence eye movements in the laboratory. We found three circumstances that frequently occur in flight in which aviators with visual symptoms had different oculomotor responses than did asymptomatic aviators. Further work needs to be done to determine why symptomatic aviators respond differently from asymptomatic ones.