IMAGE No. 17/17 The co-reaction of vitiligo patches at varying distance from the treated achromic region. Focused light particles penetrate into the skin and cause activation (or reactivation) of the affected cell structures, which transfer excess energy to surrounding structures and often even to remote ones. The light ray focused by the Ratok®derm equipment on one vitiligo patch is active on the cells of the irradiated region, as well as (blue arrows) on close-by vitiligo patches. This could be accounted for by the onset of skin intraconductivity.