Abstract
Transient adaptation refers to the rapid adjustments in sensitivity that the visual system is forced to undergo when exposed to abrupt changes in the intensity of an indirectly-viewed peripheral glare source (early glare adaptation/recovery) or, alternatively, a directly-viewed adapting field (early light/dark adaptation). Previous research from two different laboratories seems to provide somewhat conflicting evidence regarding the effect of age on transient adaptation. In the 1980s, Sturr and his collaborators published a number of studies of early light adaptation which suggested that transient adaptation depended upon age. They found that the magnitude of the threshold elevation associated with the initial onset of an abrupt increment in adapting field (AF) luminance (from 0.1 to 11.7 td) was less in older than in younger subjects. More recently, Higgins and White (1999), using low intensity (5 or 55 lux) peripheral glare sources, reported results which agreed with those of Sturr et al. in suggesting that transient adaptation depended upon age. However, unlike Sturr et al., Higgins and White reported the magnitude of the threshold elevation associated with the initial onset of a 1 second duration peripheral glare source exposure was relatively unaffected by age. Rather, increasing age delayed the recovery of sensitivity during the 1 second glare exposure. Methodological differences between the two laboratories will be offered as a means of resolving these apparently discrepant findings.