The invention concerns a lamp device for a motor vehicle, comprising at least one reflector, a light source producing a set of light signals possibly being reflected by the reflector, an output lens, comprising an input surface, an output surface and a focus, for producing a light beam, and a mask disposed between the reflector and the output lens for implementing a cutoff in the light beam produced. According to the invention, the output lens comprises a set of arrangements implemented in at least one circumferential part of the output surface of the lens, this set being capable of deviating in a given direction some of the light signals encountering this arrangement.