Disclosed is a method wherein the following steps are performed: a) the subject is placed in a natural posture, in which at least one of the gaze directions of the subject points to a visual target, b) an image capture apparatus is placed between the head of the subject and the visual target, c) the relative posture of the image capture apparatus and head of the subject is adjusted in order for the pupil of the image capture apparatus to be positioned close to the gaze direction of at least one of the eyes of the subject, d) an image of the head of the subject is captured, and e) the at least one geometrico-morphological parameter is deduced from this image.