Patent ID: 8408701

Claim:
A method for generating a trimming setpoint for trimming an ophthalmic lens ( 30 ) that is to be fitted in a surround ( 11 , 21 ) of a spectacle frame ( 10 , 20 ), comprising steps consisting in: a) within a coordinate system of the surround ( 11 , 21 ) identified by a horizontal axis (X 1 ), acquiring the shape of a longitudinal profile ( 50 ) of said surround ( 11 , 21 ) and the perimeter length (I 1 ) of this acquired longitudinal profile ( 50 ); b) within an optical coordinate system of the ophthalmic lens ( 30 ) which is identified by a centering point ( 34 ) and by a horizontal axis (X 2 ) and which is made to coincide with the coordinate system of the surround, centering and orienting said acquired longitudinal profile ( 50 ), c) projecting said acquired longitudinal profile ( 50 ) onto a curved surface deduced from a curvature parameter of said ophthalmic lens ( 30 ) or from a curvature parameter of said spectacle frame ( 10 , 20 ), d) correcting the shape of said projected longitudinal profile ( 52 ), so as to equalize its perimeter length (I 3 ) with the perimeter length (I 1 ) of the acquired longitudinal profile ( 50 ), e) deducing from said corrected longitudinal profile ( 53 ) said trimming setpoint, wherein, in step d), the correction is made in two operations consisting in: stretching, according to a given mathematical function (f), the projected longitudinal profile ( 52 ) along an ordinate axis (Y 1 , Y 2 ) transversal to said horizontal axis (X 1 , X 2 ), and in compressing the stretched longitudinal profile ( 52 ′) along an axis (X 1 , X 2 ) orthogonal to said ordinate axis (Y 1 , Y 2 ).