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Publication AbstractsUsing Diplopia as a Warning of an Inappropriate Visual (Ocular) Accommodative Response (WIVAR)J. S. Wolffsohn, B.Sc., Ph.D., G. K. Edgar, B.Sc., Ph.D., and N. A. McBrien, B.Sc., Ph.D.Aviat Space Environ Med 2001; 72:652-8 AbstractBackground: Over-accommodation, a tendency to focus at a distance closer than the desired distance, has been previously shown to occur when using a head-up display (HUD). Methods: A simple system was developed as a warning of an inappropriate visual accommodative response (WIVAR) during flight training. Two lines, which are seen as four low-contrast lines (physiological diplopia) if the user is focused in the distance due to the link between convergence and accommodation, are projected onto the pilot's HUD combiner. Results: The results show that by using the WIVAR system the accommodative response can be kept more distant when viewing forward-looking infra-red imagery (by 0.12 ± 0.04 D; p < 0.05), performing a high cognitive workload task (by 0.07 ± 0.03 D; p < 0.05) and especially when viewing in a Ganzfeld (by 0.41 ± 0.12 D; p < 0.01). Conclusion: While collimated HUD imagery stimulates the user to a more distant focus, the use of the WIVAR lines can cause additional relaxation of accommodation.Keywords: FLIR, cognition, head-up displays (HUDs), aircraft, accommodation, workload. Information on subscribing, and on obtaining copies of an article or of an entire issue. Table of Contents for Volume 72, Number 7 of the ASME journal.
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