A measurement device for implementing a measurement method comprising the following steps, • causing a person to observe with a pair of eyeglasses a point situated in front and at infinity while holding the head naturally in a substantially horizontal direction, said pair of eyeglasses occupying a natural position on the person's face; • acquiring a first image of the position of the frame in this first posture with an image acquisition system (7, 17); • causing the person to observe a target (8, 18) placed in a known position relative to an image acquisition system, by adopting a position that is natural and comfortable, said observation causing the person's head to be moved in tilting, the pair of eyeglasses conserving an unchanged position on the person's face relative to the first posture; • acquiring a second image of the position of the frame in this second posture, by means of the same image acquisition system (7, 17) as was used for the first posture; • determining the positions of the eyes from one of the two images; • computer processing of the two images obtained in order to determine the morpho-geometrical parameters of the person from the positions of the eyes, from the position of the frame in the first posture, from the position of the frame in the second posture, and from the angle of inclination of the image acquisition system (7, 17), said processing including a calculation correction to take account of a difference in inclination of the plane of the person's face relative to the gaze axis from the eyes to the gaze point, between the first and second positions; and • providing the results of the measurements, Characterized in that it comprises, a tablet combining a computer, an inclinometer and a display screen, said measurement device further comprising an assembly comprising at least one camera (7, 17) which is dissociated from said tablet and which is fitted with an inclinometer, a flash (9, 19) and a target (8, 18), and in that it comprises a stand (3, 13) and a support rod (4, 14) on which said tablet and said assembly are mounted, said support rod (4, 14) being adjustable in tilt on said stand (3, 13). • causing a person to observe with a pair of eyeglasses a point situated in front and at infinity while holding the head naturally in a substantially horizontal direction, said pair of eyeglasses occupying a natural position on the person's face; • acquiring a first image of the position of the frame in this first posture with an image acquisition system (7, 17); • causing the person to observe a target (8, 18) placed in a known position relative to an image acquisition system, by adopting a position that is natural and comfortable, said observation causing the person's head to be moved in tilting, the pair of eyeglasses conserving an unchanged position on the person's face relative to the first posture; • acquiring a second image of the position of the frame in this second posture, by means of the same image acquisition system (7, 17) as was used for the first posture; • determining the positions of the eyes from one of the two images; • computer processing of the two images obtained in order to determine the morpho-geometrical parameters of the person from the positions of the eyes, from the position of the frame in the first posture, from the position of the frame in the second posture, and from the angle of inclination of the image acquisition system (7, 17), said processing including a calculation correction to take account of a difference in inclination of the plane of the person's face relative to the gaze axis from the eyes to the gaze point, between the first and second positions; and • providing the results of the measurements,