Dimosthenis Karatzas


Refereed Papers

Colour-Opponent Mechanisms are not Affected by Sensitivity Changes Across the Life Span

S. Wuerger, C. Fu, K. Xiao and D. Karatzas

Proceedings proceedings of the 11th Congress of the International Colour Association (AIC), Sydney, Australia, September 2009


Purpose. The purpose of this study was to assess in a large sample of adult colour-normal observers of a wide age group (n=185; age range: 18-75) whether sensitivity changes due to ageing are associated with corresponding changes in the colour-opponent mechanisms that mediate hue perception. We therefore obtained the following data in the same set of observers: the sensitivity along the protan, deutan and tritan line and setting for the four unique hues from which the characteristics of the colour-opponent mechanisms can be derived. Results. We find a significant decrease in chromatic sensitivity with increasing age, in particular along the tritan line. When we predict the relative cone weights (L:S) of the colour-opponent mechanisms from the chromatic (protan, deutan, tritan) thresholds, we find a pronounced dependency on age. The observed relative cone weights (associated with a particular hue), on the other hand, are rather constant throughout the life span. Conclusion. The weighting of the cone inputs by the colour-opponent mechanisms (redgreen; yellow-blue) appears to change with age. Such an adaptive weighting with is useful to maintain colour constancy throughout the life span in the presence of known changes in the ocular media and retinal sensitivity losses.

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