A method, implemented by computer, for automatically determining at least one parameter associated with an ophthalmic device selected by an individual, said ophthalmic device comprising a frame so-called the selected frame, said determination being performed based on an image of the face of the individual wearing a frame of an ophthalmic device, so-called the worn frame, said worn frame being the frame of a second ophthalmic device, said image being acquired by an image acquisition system, the image acquisition system being calibrated metrically, the method comprising the steps of: - detecting at least one characteristic point of at least one eye of the individual on the acquired image and estimating, in the reference frame of the image acquisition system, the three-dimensional position of the detected characteristic point(s), the estimation of said three-dimensional position being performed either by triangulation of the 2D position of the characteristic point(s) in each of the acquired images simultaneously in a stereoscopic manner by at least two cameras of the image acquisition system, or using a depth camera of the image acquisition system; - detecting the worn frame and estimating the three-dimensional position of the worn frame in the reference frame of the image acquisition system by aligning a three-dimensional representation of the worn frame with the worn frame in the acquired image; - positioning, in the reference frame of the image acquisition system, a three-dimensional representation of the selected frame, the representation of the selected frame being positioned with respect to the representation of the worn frame via a positioning offset between the two frames, said offset being established beforehand; - expressing the position of each characteristic point with respect to the three-dimensional representation of the selected frame; - determining the parameter(s) based on the relative position of the characteristic point(s) of the eye(s) with respect to the three-dimensional representation of the selected frame. - detecting at least one characteristic point of at least one eye of the individual on the acquired image and estimating, in the reference frame of the image acquisition system, the three-dimensional position of the detected characteristic point(s), the estimation of said three-dimensional position being performed either by triangulation of the 2D position of the characteristic point(s) in each of the acquired images simultaneously in a stereoscopic manner by at least two cameras of the image acquisition system, or using a depth camera of the image acquisition system; - detecting the worn frame and estimating the three-dimensional position of the worn frame in the reference frame of the image acquisition system by aligning a three-dimensional representation of the worn frame with the worn frame in the acquired image; - positioning, in the reference frame of the image acquisition system, a three-dimensional representation of the selected frame, the representation of the selected frame being positioned with respect to the representation of the worn frame via a positioning offset between the two frames, said offset being established beforehand; - expressing the position of each characteristic point with respect to the three-dimensional representation of the selected frame; - determining the parameter(s) based on the relative position of the characteristic point(s) of the eye(s) with respect to the three-dimensional representation of the selected frame.