Individual Responses to Lighting Parameters for a Population of 235 Observers of Varying Ages

Abstract

The authors present the results of a comprehensive study of the effects of observer age upon various relationships between lighting parameters, task visibility, and dynamic visual performance. Included are studies of the effects of age (a) in reducing effective task visibility by increasing visibility threshold, (b) in increasing visibility needs for equal visual performance, (c) in increasing the benefits of increases in the level of illumination due to changes in the shape of the RCS function of luminance, (d) in suggesting use of substantially higher levels of illumination to compensate for losses in the transmittance of the ocular media, and (e) in increasing sensitivity to the disability glare effect, thus emphasizing an increase in the importance of lighting quality for older observers. Of perhaps special interest is the finding that disability glare effect is more than 1.5 times as great a detriment to visual performance in night driving as had been previously supposed.