Effects of healthy aging on visual detection and discrimination: evidence from contrast, texture, motion, stereo and colour thresholds

Abstract

During normal aging both the optics and the retina of the eye changes, primarily deteriorating visual acuity. Relatively little is known about other visual abilities and the effects of aging on the primary visual pathway. Improving the knowledge about perceptual abilities in the elderly is essential for understanding impaired visual functions after brain damage (such as stroke), particularly because of the required differentiation between age-based and damage-specific perceptual decline.

Here we examined the influence of age on the performance in both visual detection and discrimination using various visual submodalities (contrast, texture, motion, stereo, colour; see also Kraft et al., this conference), with the same stimulus position and stimulus type in both tasks. Perceptual thresholds were obtained for each submodality and for each visual field quadrant using a spatial four-alternative-forced-choice method controlled by an adaptive staircase procedure (converging to 62.5% correct responses). Fifty-two healthy subjects between 21 and 75 years were tested and subdivided into five groups according to their age. Perceptual thresholds significantly increased with age for all submodalities and for both tasks (detection and discrimination). These results indicate that visual perception generally declines across different visual submodalities during healthy aging. The relation between psychophysically measured decrease of different visual functions and optical, retinal and neuronal changes as well as how these methods can evaluate visual perception after brain damage are discussed.

Footnotes

 This work was supported by the German Research Foundation [BR 1691/5-1].