A system and an apparatus are provided, for gaze tracking within a defined operating range. The apparatus includes at least one optical system, which capable of capturing radiation in a wavelength range produced by a composite illumination source. The apparatus also includes at least one set of illumination sources creating the composite illumination source, wherein: at least one of the illumination sources is positioned relative to the optical system such that it ensures a user bright pupil response at the beginning of the apparatus operating range; and the composite illumination source size is such that it creates a Purkinje image on a user's eye capable of being distinguished by the optical system at the end of the apparatus operating range. The apparatus also includes an illumination controller for activating and deactivating the at least one composite illumination source, and a signal processing controller for transmitting generated images from the at least one optical system.