Comparison of angular frequency contrast sensitivity in young and older adults.
The aim of the present study was to measure contrast sensitivity curves for angular frequencies in the range between 2 and 96 cycles/360 masculine in older human adult volunteers and to compare these measurements with the more usual contrast sensitivity functions for sine-wave gratings. All subjects were free of identifiable ocular disease and had normal acuity. We measured the contrast thresholds for young adults (N=6; age range, 20-26 years) and older adults (N=6; age range, 60-67 years) using the psychophysical forced-choice method. In this paradigm the volunteers had to choose the stimulus containing a test frequency at low contrast (e.g., either a sine-wave grating or an angular frequency stimulus), or another neutral stimulus at mean luminance (without any contrast). Older adults presented a loss in contrast sensitivity at high and medium angular frequencies compared to the young adults (i.e., from 8 to 96 cycles/360 degrees). Contrary to expectation, contrast sensitivity at low angular frequencies, i.e., 2 and 4 cycles/360 degrees, was better for the older group than for the younger group. On the other hand, contrast sensitivity for sine-wave gratings at 3 and 4 cpd was higher for young adults as expected. These results suggest age-related changes in the contrast sensitivity function for angular frequencies.
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Departamento de Psicologia, Universidade Federal da Paraíba, Jõao Pessoa, PB, Brasil. natanael@ufpe.br
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Nogueira
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D000328:Adult; D000367:Age Factors; D000368:Aged; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods*; D012684:Sensory Thresholds; D014796:Visual Perception / Q000502:physiology*