Patent ID: 8814354

Claim:
A process for designing an ophthalmic progressive eyeglass, comprising the following Steps: Step- 1 providing an ophthalmic prescription for a wearer of the eyeglass, comprising prescribed values respectively of a far vision optical power, an astigmatism correction and an addition; Step- 2 providing a target value for at least one optical design feature of the eyeglass to be manufactured; Step- 3 providing at least one initial eyeglass front surface, with an initial first addition value and a first value for a surface design feature connected to said optical design feature; Step- 4 providing at least one initial eyeglass back surface, with an initial second addition value and a second value for the surface design feature, the first and second values of said surface design feature being different from one another when said initial front and back surfaces are provided with one and same addition value by surface derivation; Step- 5 computer-simulating the eyeglass using: a final front surface derived from the initial front surface for changing the initial first addition value into a final first addition value for said final front surface; a final back surface derived from the initial back surface for changing the initial second addition value into a final second addition value for said final back surface; and a transparent medium intermediate between the final front and back surfaces; at least one of the final front and back surfaces being further combined with a spherical or toric surface so that the computer-simulated eyeglass exhibits the prescribed values of the far vision optical power and the astigmatism correction, and the final first and second addition values being selected so that the eyeglass exhibits substantially the prescribed addition value and the target value for said optical design feature.