Disclosed is gaze-tracking system for head-mounted display apparatus, the gaze-tracking system including a plurality of non-circular light sources that emit light for illuminating a user's eye when the display apparatus is worn by user, at least one camera, and a processor. The processor is configured to control the at least one camera to capture an image of user's eye and reflections of the plurality of non-circular light sources from user's eye; identify at least one of the plurality of non-circular light sources from where at least one of the reflections originated, based upon shapes, rotational orientations and relative positions of the reflections of the plurality of non-circular light sources, to differentiate said reflections from visual artifacts; and detect a gaze direction of user based upon a relative position of a pupil of user's eye with respect to the reflections of the plurality of non-circular light sources.