Abstract
Color appearance is effectively compensated for the progressive yellowing of the lens with age, but the time course and mechanisms of these adjustments remain poorly understood. We examined how observers adapted to the sudden introduction of an “aged lens” by wearing glasses with yellow filters that approximated the average lens transmittance of a 70 year old at shorter wavelengths. The glasses were worn over a period of 5 days for 8 hours per day while the individuals (4 young adults) pursued their normal activities. Achromatic settings were measured before and after each daily exposure with the glasses on or off, with each setting preceded by 5 minutes of dark adaptation to remove biases owing to short-term chromatic adaptation. Stimuli were 2 deg fields shown for 250 msec with 1.5 sec intervals and displayed on a CRT. The chromaticity varied in a staircase and was confined to the axis extending through a nominal white point of Illuminant E with or without the glasses. Over repeated days there was a weak but progressive drift of the achromatic settings toward blue, consistent with a partial renormalization for the yellow lens. By the 5th day this averaged roughly 40% of complete compensation. This drift was also evident in the settings made at the beginning versus end of each daily session when the glasses were on, which again showed partial compensation. Surprisingly, the adaptation build-up on each day was not accompanied by an aftereffect when the glasses were removed (and after dark adapting) at the end of the day. This could reflect a contribution of a context-specific adaptation contingent on wearing the glasses. Our results are consistent with evidence (e.g. Delahunt et al. Visual Neuroscience 2004) pointing to a very sluggish mechanism underlying renormalization of color appearance as the spectral characteristics of the lens change.
Meeting abstract presented at VSS 2015