Method for determining an optical system of a personalized progressive lens for a given wearer comprising the following consecutive steps: a) providing a mean direction of gaze determined for the wearer in a reference frame tied to the head of the said wearer； b) determination of a target value for at least one optical design parameter as a function of the mean direction of gaze determined in step a)； c) calculation of the optical system of the progressive lens by an optical optimization procedure on the basis of target values where the target value of the (or of each) optical design parameter as a function of the mean direction of gaze determined in step b) is a target value.
