Using diplopia as a warning of an inappropriate visual (ocular) accommodative response (WIVAR)

J.S. Wolffsohn, G. K. Edgar, N A McBrien

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: 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.
Original languageEnglish
Pages (from-to)652-658
Number of pages7
JournalAviation, Space and Environmental Medicine
Volume72
Issue number7
Publication statusPublished - Jul 2001

Keywords

  • Accommodation, Ocular
  • Adult
  • Aerospace Medicine
  • Analysis of Variance
  • Aviation
  • Diplopia
  • Eye Diseases
  • Female
  • Humans
  • Male

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