Patent ID: 8540366

Claim:
A method for manufacturing a progressive spectacle lens for an identified wearer, and customized as a function of a perception of blur by said wearer, comprising: /1/ obtaining an ophthalmic prescription for the wearer, comprising a prescribed value of optical power in far vision, a prescribed addition value and a characterization of an astigmatism of said wearer; /2/ obtaining a blur perception threshold value for the wearer; /3/ obtaining respective blur values for a series of progressive ophthalmic lenses corresponding to variable prescriptions, and for a reference direction of gaze offset transversely with respect to a meridian line of the lenses, said reference direction of gaze being determined by an elevation reference value along the meridian line and an azimuth reference value measured from and transversely with respect to said meridian line; /4/ selecting a final lens based on at least one initial lens belonging to the series used in step /3/, said final lens corresponding to the wearer's prescription and having a blur value for the elevation and azimuth reference values which exhibits a discrepancy of less than 0.50 diopters in absolute value, with respect to the blur perception threshold value obtained for the wearer in step /2/; and /5/ manufacturing the spectacle lens in accordance with the final lens selected in step /4/; wherein step /2/ comprises the following two sub-steps: /2-1/ selecting a blur perception criterion as a function of the prescribed addition value for the wearer, from among the following criteria: when the prescribed addition value for the wearer is less than or equal to a first fixed addition value, the blur perception threshold value is a first blur limit below which said wearer does not detect the blur, and beyond which said wearer detects the blur; when the prescribed addition value for the wearer lies between the first fixed addition value and a second fixed addition value greater than said first fixed addition value, the blur perception threshold value is a second blur limit below which said wearer does not experience any visual inconvenience caused by the blur, and beyond which said wearer experiences visual inconvenience caused by the blur; and when the prescribed addition value for the wearer is greater than or equal to the second fixed addition value, the blur perception threshold value is a third blur limit below which said wearer is capable of reading alphanumeric characters, and beyond which said wearer is no longer capable of reading the alphanumeric characters because of the blur; and then /2-2/ determining the blur perception threshold value for the wearer by using the selected criterion.