The invention relates to a method and device for determining the visual behavior of a person. The inventive method comprises the following steps consisting in: recording the movement of the individual's head, recording the movement of his/her eyes, determining the relative orientation of the eye in relation to the head, and determining the amount of time for which the eye is maintained in each orientation. The aforementioned amount of time is determined by collecting the records of orientations in finite intervals and counting the number of records (frequency) in each interval. Said orientations are specified using angular co-ordinates for both the head and the eye. The data are detected and processed with the aid of a device comprising light emitters (51) which are fixed to the head, cameras (63) and a screen (611, 612) for attracting the individual's gaze. The results from the method are used in order to customize the design of a lens for spectacles.