Scotopic spatiotemporal sensitivity differences between young and old adults

Authors

  • Cynthia L. Clark,

    1. School of Psychological Sciences, University of Northern Colorado, Campus Box 94, Greeley, CO
    2. Department of Ophthalmology & Vision Science, 4860 Y Street, Suite 2400, University of California, Sacramento, CA
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  • Joseph L. Hardy,

    1. Department of Ophthalmology & Vision Science, 4860 Y Street, Suite 2400, University of California, Sacramento, CA
    2. Lumos Labs, San Francisco, CA
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  • Vicki J. Volbrecht,

    1. Department of Psychology, Colorado State University, Fort Collins, CO, USA
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  • John S. Werner

    1. Department of Ophthalmology & Vision Science, 4860 Y Street, Suite 2400, University of California, Sacramento, CA
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Correspondence and reprint requests to: Vicki Volbrecht.
Tel.: 970 491 7553; Fax: 970 491 1032.
E-mail address: vicki.volbrecht@colostate.edu

Abstract

Background:  Our lab has previously demonstrated losses in contrast sensitivity to low spatial frequencies under scotopic conditions with older adults. It is not clear, however, whether the temporal frequency of a stimulus alters the relation between age and the spatial contrast sensitivity function (sCSF) under scotopic conditions.

Methods:  A maximum-likelihood, two-alternative, temporal forced-choice QUEST procedure was used to measure threshold to spatially and temporally modulated stimuli in both young (mean = 26 years) and old (mean = 75 years) adults.

Results:  In general, the shapes of the spatial and temporal CSFs were low-pass for both young and old observers; contrast sensitivity decreased at approximately the same rate with increasing spatial frequency and temporal frequency for both age groups, although the overall sensitivity of the old group was lower than that of the young group. The high-frequency resolution limit was lower for the old group compared to the young group.

Conclusions:  The differences in contrast sensitivity between the young and old groups suggest a uniform loss in sensitivity of the channels mediating spatial and temporal vision. Because of this loss, the spatial and temporal window of visibility for the older adults is compromised relative to the younger adults.

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