A near-eye display device includes (a) a display unit for displaying a display image, (b) a viewing unit for presenting the display image to the eye and transmitting ambient light from an ambient scene toward the eye, and (c) an eye imaging unit including (i) an illumination module for generating at least three infrared light beams propagating along at least three different, non-coplanar directions, respectively, (ii) a first beamsplitter interface, disposed between the display unit and the viewing unit, for merging at least a portion of each of the infrared light beams with visible display light to direct each portion toward the eye via the viewing unit, and (iii) a camera for imaging, via the viewing unit and the first beamsplitter interface, pupil of the eye and reflections of the infrared light beams incident on the eye, to form one or more images indicative of gaze direction of the eye.