Effects of ageing on postreceptoral short-wavelength gain control: Transient tritanopia increases with age

We investigated the effect of ageing on the neural gain control in the short-wavelength opponent channel. In order to tackle specifically postreceptoral changes, we determined the effect of ageing on transient tritanopia, a paradoxical and transient reduction of short-wavelength sensitivity after the presentation of a long-wavelength adapting light. The results demonstrate an unexpected and significant increase of transient tritanopia with age, which cannot be explained by a general decline of short-wave sensitivity or the selective reduction of retinal illumination. Instead, our data imply that ageing affects also short-wavelength gain control at the site of chromatic opponency or beyond. Age-related changes of adaptation processes should therefore be considered an important factor influencing the visual performances of the elderly.