Problem definition: The ocular prosthetic does not resemble the natural eyes enough, the pupil does not dilate and contract. To make the patients feel more complete the prosthesis should look as much as a natural eye as possible. Assignment: Improve the ocular prosthetic, by making it able for the pupil to dilate and contract, to let it resemble the natural eye as closely as possible. Design solution: After analyzing and discarding numerous technologies electrowetting was finally chosen as a technology. With electrowetting the wettability of a solid surface is modified by applying a voltage across a droplet and an electrode. A ionized liquid droplet of black fluid represents the pupil. A transparent repelling fluid surrounds the black droplet. The black droplet and an electrode separated from the fluids by a dielectric layer are charged. The black fluid expands its surface area and dilated. A light sensor is used to change tailor the voltage applied.