Patent ID: 8220922

Claim:
A method of determining, under wearing conditions, at least one component of the orientation of a correcting ophthalmic lens of eyeglasses relative to the head of the future wearer, the method comprising the steps of: mounting a position-identification system ( 20 ; 200 ) on the frame ( 10 ) and/or on a presentation lens ( 100 , 101 ) fitted to the frame, the identification system comprising at least one identification element ( 60 , 70 , 80 ; 700 ; 800 ) having at least one known geometrical characteristic; capturing an image of the identification element ( 60 , 70 , 80 ; 700 ; 800 ) in two dimensions in a vertical facial plane (PCI) by means of an image-capture apparatus; processing the captured image of the identification element to measure therein a geometrical characteristic that depends on the known geometrical characteristic of the identification element; and calculating at least one component of the orientation of the lens by comparing the measured geometrical characteristic of the captured image of the identification element with the known geometrical characteristic of the identification element, wherein, the position-identification system ( 20 ) includes at least one horizontal identification element ( 70 ) and means ( 25 , 26 ) for mounting said element directly or indirectly on a rim ( 11 ) of the frame ( 10 ) or on a presentation lens ( 100 ) fitted to the frame ( 10 ), the horizontal identification element ( 70 ) being arranged so that the measured geometrical characteristic of the captured image of the identification element depends on the horizontal component, about a substantially vertical axis, of the orientation of said rim ( 11 ) of the frame ( 10 ) or of said presentation lens ( 100 ) relative to the head of the wearer, and at least one horizontal component of the orientation of the correcting lens relative to the head of the wearer is calculated as a function of said comparison.