The visual coordinator uses the Haidinger’s phenomenon. The purpose of the exercise is fixation of the rotating propeller (fan). Patient with amblyopia (lazy eye) can see it only from a side. Haidinger’s brush is seen only with the macula, since it is dependent on its anatomical structure. In the macula there is a yellow pigment and a radial system of retinal fibers which makes it possible to see this phenomenon. What was used in the construction of the device is the fact that while gazing at an evenly lit, textureless surface through a polarizer we notice a form of a propeller or a bud creating an unclear dark cross. The phenomenon is more clearly visible with the use of a dark blue filter.