CONICET | Buscador de Institutos y Recursos Humanos

Previous research (Ramaswamy et al, Optom.Vis.Sci.86: 964-70,2009; Atchison et al, H.Factors, 45:495-503,2003) has shown that observers with colour deficiencies in the red-green present higher colour reaction times than normal ones to identify a traffic signal. We present results from a pilot experiment, analyzing the effect of colour-vision deficiency on reaction times -RT- of chromatic stimuli. We measured RT for 11 normal observers and two colour-deficient protanope and deuteranope- observers. The test was a modified Cambridge Colour Test (CRS Ltd; Regan et al, Vision Research 34: 1279-99, 1994). The stimulus of square shape differs from the achromatic background along one of three significant lines in colour space: protan, deutan and tritan confusion lines. RT values as a function of distance from background chromaticity show a similar pattern for all normal subjects, decreasing when distance from background increases, showing an abrupt decrement towards an asymptotic value. In contrast, colour-deficient observers present RT values larger than those for normal ones, with greater dispersion and a tendency towards a less pronounced asymptotic value. As we expected, RT values for normal observers along the tritan line are higher than those for deutan and protan line, while for the dichromatic observers this relationship is reversed. At the same time, chromatic discrimination threshold corresponding to deutan line or protan line, depending of the colour deficiencies, is higher for dichromatic observers than for normal subjects, showing a greater difference for deutan or protan line. If there are no M or L cones, the L/M channel is impaired; therefore perception of colours along deutan or protan line, respectively, is affected. Finally, RT measurements could be an appropriate way for analyzing not only the interaction between the chromatic channels but also the type of chromatic deficiencies.