New type of perceptual suppression during dynamic ocular accommodation

When viewing natural scenes saccadic eye movements are used to position retinal images of interest on the fovea, while vergence eye movements act to minimise retinal disparity and maintain a single binocular view of the target. Despite these disruptions to the retinal image, we perceive a stable visual world due to suppression of the magnocellular visual pathway which processes low spatial frequency target details [1]. Retinal image clarity is maintained by the mechanism of accommodation, which changes ocular power to produce sharp retinal images of objects at different viewing distances [2]. During abrupt dynamic changes in accommodation, visual suppression seems to occur as image degradation is rarely reported. Here, we report direct psychophysical evidence that visual suppression during dynamic accommodation really does occur. This suppression is selective for luminance modulated patterns of higher spatial frequencies, implying that the suppression is occurring in the parvocellular visual pathway, which carries colour and fine detail information.