Retinal site of transient tritanopia

Abstract

WHEN the eye is adapted to a bright yellow light, a marked loss of sensitivity for short-wavelength stimuli occurs in the first few seconds after extinction of this light. This phenomenon was first reported by Stiles¹ and has been termed transient tritanopia by Mollon and Polden². The latter authors suggest that this apparent suppression of the short-wave sensitive cones (hereafter called blue cones) during rapid dark adaptation is effected through inhibition by the recovering long- and middle-wave sensitive cone mechanisms² (hereafter called red and green cones, respectively). In this study we attempted to localise the site of blue cone inhibition through intra-retinal recordings from the intact rhesus monkey eye. We found transient tritanopia to be absent at the receptor level but present at the b-wave level, and we conclude that transient tritanopia originates at a site between the receptors and the bipolar cells, probably at the horizontal cells, as was earlier hypothesised by Augenstein and Pugh³.