Abstract: Eye tracking is performed by determining an initial pupil position of a user in relation to a lens situated in front of the user, detecting a change in pupil position in relation to the lens to an updated pupil position in relation to the lens, and determining that the updated pupil position is outside a bounding box associated with the lens. The updated pupil position is a replacement pupil position with a replacement pupil position within the bounding box associated with the lens, and the updated pupil position is utilized for eye-tracking functionality. Eye tracking is also performed by determining that a first pixel associated with a gaze direction is outside a visibility region, identifying a replacement pixel within the visibility region, determining an updated gaze angle based on the replacement pixel, and performing eye tracking using the updated gaze angle.