The underlying invention is directed to a method for changing the human perceptual color appearance of the iris of a human's or animal's eye by selectively decreasing the density of pigments of the anterior stroma layer of the iris. The method comprises generating, by a generator module, a plurality of predefined energy quantities； and applying, by the genera-tor module, one or more of the predefined energy quantities to the anterior stroma layer, wherein each of the predefined energy quantities is generated and applied, such that the energy quantities ablate, at least in part, melanocytes of the stroma whilst leaving non-melanocyte tissue of at least the stroma essentially undamaged, and wherein the predefined energy quantities generated and applied to the anterior stroma layer in the form of pressure waves and/or pulses generated within a fluid medium that is in fluidical communication with the anterior stroma layer.
