Abstract: Method for determining the feasibility of an ophthalmic lens by an ophthalmic lens manufacturing process comprising: an ophthalmic lens data providing step, a set of surface parameters providing step, an optical parameters providing step during which a set of n optical parameters (P1, P2, . . . , Pn) is provided, n being an integer greater than or equal to 1, each optical parameter Pi being provided with a tolerance value ?i, —a feasibility check determining step, during which the feasibility of the ophthalmic lens by the ophthalmic lens manufacturing process is determined by determining if for i from 1 to n: - ? i ? [ ? j = 1 m ? ( ? P i ? ? j ) 0 × ? ? ? ? j ] + A i ? ? i with ? ? ( ? P i ? ? j ) 0 the value of the derivative of Pi with respect to the jth surface parameter ?j on the nominal surface and ??j the value of the jth surface parameter and Ai a combination of terms of order greater or equal to 2 for each Pi.

Abstract: Determining position parameters defining relative position of a manufactured derivable surface relative to a reference surface, the process comprising: providing a nominal surface expressed in a nominal frame of reference and corresponding to the theoretical derivable surface to be manufactured with the nominal value of the position parameters defining the relative position of the nominal surface relative to the reference surface, providing a measured surface of the manufactured derivable surface expressed in the nominal frame of reference, providing at least one deformation surface defined by at least one deformation adjustable parameter, determining a composed surface by adding the measured surface and the deformation surface, determining the position parameters and at least one deformation parameter by minimizing the difference between the nominal surface and the composed surface.

Abstract: Determining position parameters defining relative position of manufactured derivable surface relative to reference surface, the process comprising: a step during which a nominal surface expressed in a nominal frame of reference and corresponding to the theoretical derivable surface to be manufactured with the nominal value of the position parameters defining the relative position of the nominal surface relative to the reference surface is provided, a step during which a measured surface of the manufactured derivable surface expressed in the nominal frame of reference is provided, a step (S3) during which at least one deformation surface defined by at least one deformation adjustable parameter is provided, a step (S4) during which a composed surface is determined by adding the measured surface and the deformation surface, a step during which the position parameters and at least one deformation parameter are determined by minimizing the difference between the nominal surface and the composed surface.