The Relationship Between Contrast Sensitivity and the Visual Problems of Older Drivers

Numerous age-related changes in the structure and function of the visual system have been noted in the research literature. However, little is known about the extent to which these visual changes contribute to the problems experienced by older persons in the natural environment. In an attempt to estimate the nature and magnitude of the real-world visual problems which accompany normal adult aging, a large number of male and female participants in the Baltimore Longitudinal Study on Aging (N=397) were examined. They ranged from 22 to 92 years of age with oversampling in the 65+subgroups. Participants completed a survey designed to assess the magnitude of visual problems experienced with everyday tasks and while driving an automobile. Approximately half of the participants also received a comprehensive examination of their visual status in the form of a psychophysically rigorous assessment of their contrast sensitivity function (CSF). Factor analysis of the survey responses revealed that visual problems experienced while driving increased with age. The emergence of these age-related difficulties occurred along five major dimensions: unexpected vehicles in the peripheral field, judgments of vehicle speed, dim instrument panel displays, windshield problems, and the inability to read street signs. These age-related increases in self-reported visual problems were significantly related to concomitant losses in contrast sensitivity at both intermediate and high spatial frequencies. These data point to areas of research which could yield promising benefits for improving real-world visual functioning among older adult populations.