Patent ID: 8215769

Claim:
A design method of a spectacle lens, comprising: measuring an angle formed by a direction of a head of a person facing a front direction without a lens and a direction of the head of the person in which an object is recognized, where the object is located in a direction angled to the front direction of the person without the lens; calculating the angle formed by the front direction of the person and a direction in which the object actually exists to calculate a visual action index M n according to the following equation (1) as an initial value; M n = β n α n ( 1 ) temporarily designing a spectacle lens based on the calculated visual action index M n ; and simulating visual action of the person wearing the temporarily designed spectacle lens and calculating a corrected visual action index based on the simulation result wherein α n is the angle formed by the front direction of the person and the direction in which the object actually exists, β n is a rotation angle of the head of the person in which the object is recognized without the lens, and n represents a number of objects; and when n>1, then M n is calculated as an average value, wherein the step of correcting the visual action index corrects the visual action index M n according to the following equation (2): M′ n =M n ((α′ n +|α′ nL −α′ nR |)/α n ) (2) wherein M′ n is a visual action index after correction, α′ nL is an angle formed by the front direction of the person and a direction in which the object is recognized by a left eye of the person through the spectacle lens, α′ nR is an angle formed by the front direction of the person and a direction in which the object is recognized by a right eye of the person through the spectacle lens, α′ n is the angle corresponding to the stronger eye of the person in the angles α′ nL and α′ nR .