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.
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 language | English |
|---|---|
| Pages (from-to) | 652-658 |
| Number of pages | 7 |
| Journal | Aviation, Space and Environmental Medicine |
| Volume | 72 |
| Issue number | 7 |
| Publication status | Published - Jul 2001 |
Keywords
- Accommodation, Ocular
- Adult
- Aerospace Medicine
- Analysis of Variance
- Aviation
- Diplopia
- Eye Diseases
- Female
- Humans
- Male