Habituation to progressive additional lenses – a neuronal process

Habituation to progressive additional lenses is known to be a potential challenge for novice PAL wearers. Disturbed spatial orientation and vertigo are occasionally reported after prescription of a novel pair of PALs. But, symptoms usually vanish after an extended period of wear. Potential sources for the described side effects are distortions within the visual field of the wearer induced by the power change within the PAL. A method is proposed to quantify the habituation process in terms of neuronal adaptation to image skew in dynamic natural image sequences. It allows evaluation of relevant properties of distorted visual content in triggering adaptation. In psychophysical experiments, left and right skewed natural image sequences were shown to observers as adapting stimuli. The skew amplitude in simple geometrical patterns that are perceived to be unskewed, were used to quantify an adaptation aftereffect. Spatial properties of skew adaptation were evaluated. On the basis of the presented results, insights into the neuronal processes mediating PAL habituation are presented.