Transient tritanopia experiment in blue cone monochromacy

Abstract

WHEN the eye has been adapted to a bright yellow light, a marked loss of sensitivity to short-wavelength stimuli may be recorded immediately after the extinction of the adapting field. This phenomenon, first described by Stiles¹, was termed transient tritanopia by Mollon and Polden². They supposed that a recovering long-wavelength mechanism may inhibit or otherwise suppress the blue cone signal during early dark adaptation. Transient tritanopia was found in one protanope and, in a modified form, in one deuteranope. This indicates that each of the red or green mechanisms or both in combination may give rise to the inhibition effect. It is of particular interest in this connection to know if this kind of inhibition is present in persons without red or green cones. In blue cone monochromacy, a unique kind of colour vision anomaly, there are only blue cones and no functioning red or green cones. We report here the experimental results obtained with such a person where no suppression effect upon the blue mechanism could be demonstrated. The results are compared with those of a typical rod monochromat and a person with normal vision.