A method of determining at least one parameter of an ophthalmic lens (40) including a complementary optical element (12) obtained by additive manufacturing and configured to provide at least a part of the optical function of the ophthalmic lens, the determining method including a step of providing two characterizing surfaces simulating two opposite surfaces of a complementary optical element (12), the distance between the two characterizing surfaces along a thickness axis (Z) defining the thickness of the complementary optical element; a step of optimizing the distance between the two characterizing surfaces (20) along the thickness axis (Z) so that the thickness of the complementary optical element reaches a thickness threshold while complying with the optical function of the ophthalmic lens (40); and a step of determining at least one parameter of the ophthalmic lens (40) on the basis of the optimized distance.