A method and a corresponding eye tracking system for providing an approximate gaze convergence distance of a user in an eye tracking system are disclosed. The method comprises determining (110) calibration data in relation to interpupillary distance (x) between a pupil of a left eye and a pupil of a right eye of a user, determining (120), based on the determined calibration data, a gaze convergence function (f(x)) providing an approximate gaze convergence distance of the user based on a determined interpupillary distance of the user. The method further comprises receiving (130), from one or more imaging devices (520), one or more images of the left eye and the right eye of the user, determining (140) a current interpupillary distance of the user based on the one or more images and determining (150) a current approximate gaze convergence distance based on the current interpupillary distance and the gaze convergence function.
Robust convergence signal