Patent ID: 8474979
Filing Date: 2013-07-02
Classification: G02C

Abstract:
1. A method for producing a customized progressive power ophthalmic lens intended for an identified wearer, the lens having variable optical power values along a determined meridian line on said lens, between a reference direction for far vision and a reference direction for near vision, said method comprising the following steps: /a/ for the wearer, obtaining a prescribed optical power value for far vision and a prescribed addition value, a sum of the prescribed optical power value for far vision with the prescribed addition value providing a prescribed optical power value for near vision; and /b/ presenting first visual signals at an eye height of the wearer when standing, the first visual signals being adapted to prompt a first visual task; /c/ for the wearer, walking toward the first visual signals from an initial distance measured horizontally relative to said first visual signals, while performing the first visual task; /d/ when the wearer arrives at a first distance from the first visual signals, less than the initial distance, presenting second visual signals on the ground between the wearer and said first visual signals, at a second distance measured horizontally from the first visual signals and less than said first distance, the second visual signals being adapted to prompt a second visual task, the wearer then switching from the first task to the second task; /e/ measuring first angles of inclination of the head of the wearer in a vertical plane while said wearer performs the first task then the second task; and /f/ from the first angles of inclination of the head of the wearer measured according to the step /e/ and for a fixed first deviation of the optical power relative to the prescribed optical power value for far vision, said first deviation being less than half the prescribed addition value, determining a first intermediate direction of sight through the lens intersecting the meridian line between the reference direction for far vision and the reference direction for near vision, said first intermediate direction being associated with the prescribed optical power value for far vision added to said first deviation; /g/ producing the lens so as to obtain, for the following directions through the lens: wherein step /g/ includes obtaining in the lens, for the first intermediate direction determined in the step /f/, a third optical power value corresponding to said prescribed value for far vision added to the first deviation.