Contrast Sensitivity Predicts Age-Related Differences in Highway-Sign Discriminability

Abstract

This study was conducted to detennine if contrast sensitivity could predict age-related differences in the ability to discriminate simple road signs, as these differences have not been predicted by Snellen visual acuity. Contrast sensitivity, Snellen visual acuity, and discrimination distances for projected images of highway signs were measured for 7 older observers, ages 55 to 79, and 13 younger observers, ages 19 to 30. All subjects had 20/20 visual acuity or better, but the older group had significantly lower contrast sensitivity than did the younger group at three spatial frequencies: 3, 6, and 12 cycles/deg of visual angle. The older group required a significantly larger sign symbol in order to determine if it denoted a + or T intersection. Correlations between measures showed that highway-sign discrimination distance was significantly related to contrast sensitivity at two spatial frequencies, 1.5 and 12 cycles/deg, but discrimination distance was not related to visual acuity. Implications for highway-sign design and driver vision standards are discussed.

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References

Ginsburg, A. (1978). Visual information processing based on spatial filtering constrained by biological processing (Tech. Report AMRL-TR-78–129). Wright-Patterson AFB, OH: Aerospace Medical Rcsearch Lab.

Ginsburg, A. (1980a). Proposed new vision standards for the 1980s and beyond: Contrast sensitivity. In Proceedings No. 310 of the Advisory Group for Aerospace Research and Development (pp. 123–128). Toronto, Canada: Advisory Group for Aerospace Research and Development.

Ginsburg, A. (1980b). Specifying relevant spatial information for image evaluation and display design: An explanation of how we see certain objects. In Proceedings of the Society for Information Display (pp. 219–227). Los Angeles: Society for Information Display.

Ginsburg, A. (1981). Spatial filtering and vision: Implications for normal and abnormal vision. In L. Proenza , J. Enoch , and A. Jamplosky (Eds.), Applications of psychophysics to clinical problems (pp. 70–106). New York: Cambridge University Press.

Ginsburg, A. (1984). Sine-wave gratings are more visually sensitive than disks or letters. Journal of the Optical Society of America, 1, 1301.

Ginsburg, A. , and Cannon, M. (1983). Comparison of three methods for rapid determination of threshold contrast sensitivity. Investigative Ophthalmology and Visual Science, 24, 798–802.

Ginsburg, A. , Cannon, M. , and Nelson, M. (1980). Suprathreshold processing of complex visual stimuli: Evidence for linearity in contrast perception. Science, 208, 619–621.

Ginsburg, A. , and Evans, D. (1981). Relationships between individual differences in contrast sensitivity and the detection and identification of targets. In Proceedings of the Annual Meeting of the Association of Aerospace Medicine (pp. 80–81). San Antonio, TX: Association of Aerospace Medicine.

Ginsburg, A. , Evans, D. , Sckuler, R. , and Harp, S. (1982). Contrast sensitivity predicts pilots' performance in aircraft simulators. American Journal of Optometry and Physiological Optics, 5 9(1). 105–109.

10.

McNelis, J. F. , and Guth, S. K. (1969). Visual performance --Further data on complex test objects. Illuminating Engineering, 64, 99–102.

11.

Owsley, C. , Sekuler, R. , and Boldt, C. (1981). Aging and low-contrast vision: Face perception. Investigative Ophthalmology and Visual Science, 21, 362–368.

12.

Sivak, M. , Olson, P. , and Pastalan, L. (1981). Effect of driver's age on nighttime legibility of highway signs. Human Factors, 23, 59–64.