Previous experiments have raised the possibility that abnormal oculomotor functioning could be the substrate for visual problems among aviators who use helmetmounted 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.
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References
1.
Behar, I., Wiley, R. W., Levine, R. R., Rash, C. E., Walsh, D. J., and Cornum, R. L. S. (1990). Visual survey of Apache aviators (Tech. Report 90-15). Fort Rucker, AL: V.S. Army Aeromedical Research Laboratory.
2.
Campbell, F. W. (1960). Correlation of accommodation between the two eyes. Journal of the Optical Society of America, 50, 738.
3.
Coleman, H. S., Coleman, M. F., and Fridge, D. L. (1951). Theory and use of the dioptometer. Journal of the Optical Society of America, 41, 94–97.
4.
Cornsweet, T. N., and Crane, H. D. (1970). Servo-controlled infrared optometer. Journal of the Optical Society of America, 60, 548–554.
5.
Crane, H. D., and Steele, C. M. (1985). Generation-V dual-Purkinje-image eyetracker. Applied Optics, 24, 527–537.
6.
Duane, A. (1915). Anomalies of accommodation clinically considered. Transactions of the American Ophthalmological Society, 14, 386–398.
7.
Hale, S., and Piccione, D. (1990). Pilot performance assessment of the AH-64A helmet display unit (Tech. Note 1-90). Aberdeen Proving Ground, MD: U. S. Army Human Engineering Laboratory.
8.
Hennessy, R. T. (1975). Instrument myopia. Journal of the Optical Society of America, 65, 1114–1120.
9.
Hull, J. C., Gill, R. T., and Roscoe, S. N. (1982). Locus of the stimulus to visual accommodation: Where in the world, or where in the eye?Human Factors, 24, 311–319.
10.
Iavecchia, J. H., Iavecchia, H. P., and Roscoe, S. N. (1988). Eye accommodation to head-up virtual images. Human Factors, 30, 689–702.
11.
Kotulak, J. C., and Morse, S. E. (1994a). Focus adjustment effects on visual acuity and oculomotor balance with aviator night vision displays. Aviation, Space and Environmental Medicine, 65, 348–352.
12.
Kotulak, J. C., and Morse, S. E. (1994b). Relationship among accommodation, focus, and resolution with optical instruments. Journal of the Optical Society of America A, 11, 71–79.
13.
Kotulak, J. C., and Morse, S. E. (1995). The effect of perceived distance on accommodation under binocular conditions. Vision Research, 35, 791–795.
14.
Kotulak, J. C., Morse, S. E., and Wiley, R. W. (1994). The effect of knowledge of object distance on accommodation during instrument viewing. Perception, 23, 671–679.
15.
Kotulak, J. C., and Schor, C. M. (1987). The effects of optical vergence, contrast, and luminance on the accommodative response to spatially bandpass filtered targets. Vision Research, 27, 1797–1806.
16.
Kruger, P. B., and Pola, J. (1985). Changing target size is a stimulus for accommodation. Journal of the Optical Society of America A, 2, 1832–1835.
17.
Leibowitz, H. W., and Owens, D. A. (1975). Anomalous myopias and the intermediate dark focus of accommodation. Science, 189, 646–648.
18.
McCready, D. W., Jr. (1965). Size-distance perception and accommodation-convergence micropsia–A critique. Vision Research, 5, 189–206.
19.
McLin, L. N., Schor, C. M., and Kruger, P. B. (1988). Changing size (looming) as a stimulus to accommodation and vergence. Vision Research, 28, 883–898.
20.
Moffitt, K. (1989). Ocular responses to monocular and binocular helmet mounted display configurations. In Proceedings of the Society of Photo-Optical Instrumentation Engineers (Vol. 1116, pp. 142–148). Bellingham, WA: Society of Photo-Optical Instrumentation Engineers.
21.
Norman, J., and Ehrlich, S. (1986). Visual accommodation and virtual image displays: Target detection and recognition. Human Factors, 28, 135–151.
22.
Ogle, K. N. (1950). Researches in binocular vision. Philadelphia: Saunders.
23.
Ono, H., Muter, P., and Mitson, L. (1974). Size-distance paradox with accommodative micropsia. Perception and Psychophysics, 15, 301–307.
24.
Roscoe, S. N. (1987). The trouble with HUDs and HMOs. Human Factors Society Bulletin, 30(7), 1–3.
25.
Schor, C. M., and Kotulak, J. C. (1986). Dynamic interactions between accommodation and convergence are velocity sensitive. Vision Research, 26, 927–942.
26.
Schor, C. M., Kotulak, J. C., and Tsuetaki, T. (1986). Adaptation to tonic accommodation reduces the lag of accommodation and is masked in darkness. Investigative Ophthalmology and Vision Science, 27, 820–827.
27.
Simonelli, N. M. (1979). The dark focus of accommodation: Its existence, its measurement, its effects (Tech. Report 82-0294). Bolling Air Force Base, DC: Office of Scientific Research.
28.
Simonelli, N. M., and Roscoe, S. N. (1979). Apparent size and visual accommodation under day and night conditions (Tech. Report 81-0801). Bolling Air Force Base, DC: Office of Scientific Research.
29.
Smith, G. (1983). The accommodative resting states, instrument accommodation, and their measurement. Optica Acta, 30, 347–359.
