This article proposes that adaptation to the fundamental spatial frequency of lines of text on a video display terminal (VDT) provides a single explanation for a wide variety of reports of visual fatigue by VDT users. Reliable contrast threshold elevations at spatial frequencies of 2, 3, and 5 cycles/deg were found after subjects read single-spaced text on a VDT. This adaptation also reduces sensitivity to spatial frequencies in the range (2 to 6 cycles/deg) largely responsible for the reflexive accommodative response (Bour, 1981. Charman and Heron, 1979), and therefore could account for objective optometric measures of disturbed accommodation as well as some subjective effects of VDT viewing. Implications for video display design and for further research are discussed.
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References
1.
Blakemore, C., and Campbell, F. W. (1969). On the existence of neurons in the human visual system selectively sensitive to the orientation and size of retinal images. Journal of Physiology, 203, 237–260.
2.
Blakemore, C., and Sutton, P. (1969). Size adaptation: A new aftereffect. Science, 166, 245–247.
3.
Bour, L. J. (1981). The influence of the spatial distribution of a target on the dynamic response and fluctuations of the accommodation of the human eye. Vision Research, 21, 1287–1296.
4.
Cakir, A., Hart, D. J., and Stewart, T. F. M. (1980). Visual display terminals: A manual covering ergonomics, workplace design, health and safety, task organization. Chichester, U.K.: Wiley.
5.
Campbell, F. W., and Robson, J. G. (1968). Application of Fourier analysis to the visibility of gratings. Journal of Physiology, 197, 551–566.
6.
Campbell, F. W., and Green, D. G. (1965). Optical and retinal factors affecting visual resolution. Journal of Physiology, 181, 576–593.
7.
Charman, W. N., and Heron, G. (1979). Spatial frequency and the dynamics of the accommodation response. Optica Acta, 26, 217–228.
8.
Charman, W. N., and Tucker, J. (1977). Dependence of accommodation response on the spatial frequency spectrum of the observed object. Vision Research, 17, 129–139.
9.
Dainoff, M. J., and Happ, A. (1981). Visual fatigue and occupational stress in VDT operators. Human Factors. 23, 421–438.
10.
Ferguson, D. A., Major, G., and Keldoulis, T. (1974). Vision at work: Visual defect and the visual demand of tasks. Applied Ergonomics, 5(2), 84–93.
11.
Geacintov, T., and Peavler, W. (1974). Pupillography in industrial fatigue assessment. Journal of Applied Psychology, 59, 213–216.
12.
Gelb, D. J., and Wilson, H. R., (1983). Shifts in perceived size as a function of contrast and temporal modulation. Vision Research. 23, 71–82.
13.
Georgeson, M. A., and Sullivan, G. E. (1975). Contrast constancy: Deblurring in human vision by spatial frequency channels. Journal of Physiology, 252, 627–656.
14.
Gould, J. D., and Grischkowsky, N. (1984). Doing the same work with hard copy and with cathode-ray (CRT) computer terminals. Human Factors, 26, 323–337.
15.
Grandjean, E.Hünting, W., and Pidermann, M. (1980). VDT workstation design: Preferred settings and their effects. Human Factors, 25, 161–175.
16.
Gunnarsson, E., and Soderberg, I. (1983). Eye strain resulting from VDT work at the Swedish Telecommunications Administration. Applied Ergonomics, 14(1), 61--69.
17.
Hennessy, R. T., Iida, T., Shiina, K., and Leibowitz, H. W. (1976). The effects of pupil size on accommodation. Vision Research. 16, 587–589.
18.
Hopkinson, R. G., and Collins, J. B. (1970). The ergonomics of lighting. London: MacDonald Technical and Scientific Press.
19.
Krivohlavy, J., Kodat, V., and Cizek, P. (1969). Visual efficiency and fatigue during the afternoon shift. Ergonomics, 12, 735–740.
20.
Laübli, T., Hünting, W., and Grandjean, E. (1981). Postural and visual loads at VDT workplaces. II. Lighting conditions and visual impairments. Ergonomics, 24(12).
21.
Levinson, J. Z., and Frome, F. S. (1979). Perception of size of one object among many. Science, 206, 1425–1426.
22.
Malmstrom, F. V., Randle, R. J., Murphy, M. R., Reed, L. E., and Weber, R. J. (1981). Visual fatigue: The need for an integrated model. Bulletin of The Psychonomic Society, 17, 183–186.
23.
Mourant, R. R., Lakshmanan, R., and Chantadisai, R. (1981). Visual fatigue and cathode ray tube display terminals. Human Factors, 23, 529–540.
24.
Owens, D. A. (1980). A comparison of accommodative responsiveness and contrast sensitivity for sinusoidal gratings. Vision Research, 20, 159–167.
25.
Rinalducci, E. J. (1983). Video displays, work, and vision. Washington, DC: National Academy Press.
26.
Schade, O. H. (1956). Optical and photoelectric analog of the eye. Journal of the Optical Society of America, 46, 721–739.
27.
Smith, W. J. (1979). A review of literature relating to visual fatigue. In Proceedings of the Human Factors Society 23rd Annual Meeting (pp. 362–366). Santa Monica, CA: Human Factors Society.
28.
Tolhurst, D. J. (1973). Separate channels for the analysis of the shape and movement of a moving visual stimulus. Journal of Physiology, 231, 385–402.
29.
Wilkins, A. J., and Nimmo-Smith, I. (1984). On the reduction of eye-strain when reading. Ophthalmic and Physiological Optics, 4, 53–59.
30.
Zwahlen, H. T. (1984). Measurement of visual and performance adaptation behavior on video display terminals. In Proceedings of the International Conference on Occupational Ergonomics (Vol. 1) (pp. 242–246).
31.
Zwahlen, H. T., Hartmann, A. L., and Rangarajulu, S. L. (1984). Video display terminal work with a hard copy-screen and a split screen data presentation (NIOSH Publication No. 83–1775). Cincinnati, OH: NIOSH.
