Patent ID: 7997726
Filing Date: 2011-08-16
Classification: G02C

Abstract:
1. Method for determining by optimization a set of progressive ophthalmic lenses for a given wearer to whom a near-vision power addition (Add n ) has been prescribed, comprising the steps of: measuring individual physiological parameters of the wearer in near-vision; determining an ergorama associating, on each lens, a point aimed at for each direction of view under wearing conditions, determining a power defect target and a resulting astigmatism target for each direction of view under wearing conditions, the target power defect and the target resulting astigmatism being determined from the measured physiological parameters of the wearer; calculating the power required on each lens for said ergorama by successive iterations to achieve the target power defect and the target astigmatism defect for each direction of view wherein the measured physiological parameters of the wearer include one or more of: the vertical coefficient of participation of the head in near-vision, defined as the ratio of the elevation of the head to the lowering of view for a direction of view when the wearer aims at a near-vision target point; the horizontal coefficient of participation of the head in near-vision, defined as the ratio of the orientation of the head in the horizontal plane to the orientation of view in this same plane when the wearer aims at a near-vision target point; the vertical horopter in near-vision, defined as the angle formed by the direction of view with a document containing the point aimed at; and the preferred near-vision distance, defined as the distance between the eye and the document containing the point aimed at, and in which the power defect target is determined by the following relationship: with, wherein, ProbH′, the probability of occurrence of the orientation of view is determined by the following relationship: with, where,