Patent ID: 6994435

Claim:
A spectacle lens having an outer surface and an inner surface, one of the outer and inner surfaces being configured to be a rotationally-asymmetrical aspherical surface, when a curvature at a coordinate (h,θ) of the outer surface is represented by C 1 (h,θ), a curvature at a coordinate (h,θ) of the inner surface is represented by C 2 (h,θ), and a difference between curvatures of the outer surface and the inner surface at the coordinate (h,θ) is represented by C 2-1 (h,θ)=C 2 (h,θ)−C 1 (h,θ), if C 2-1 (0,θ)>0, said spectacle lens satisfying a condition (1): C 2-1 ( h,θ+ 180)− C 2-1 ( h ,θ)>0 (1), and if C 2-1 (0,θ)<0, said spectacle lens satisfying a condition (2): C 2-1 ( h, θ+ 180)− C 2-1 (h,θ)<0 (2) wherein the conditions (1) and (2) hold within ranges of 10 mm≦h≦20 mm and 30°≦θ≦150°, wherein given that a normal line which is normal to the outer surface through a centration point is regarded as a z 1 -axis, a direction which is perpendicular to the z 1 -axis and which corresponds to an upward direction in the state of wearing of said spectacle lens is regarded as a y 1 -axis, and a direction which is perpendicular to the y 1 -axis and the z 1 -axis in a left hand coordinate system is regarded as an x 1 -axis, the coordinate (h,θ) of the outer surface is defined as a point having a height h (unit: mm) from the z 1 -axis on an intersection line which is formed between the outer surface and a plane including the z 1 -axis and forming an angle θ (unit: degree) with respect to the x 1 -axis, wherein given that a normal line which is normal to the inner surface through the centration point is regarded as a z 2 -axis, a direction which is perpendicular to the z 2 -axis and which corresponds to the upward direction in the state of wearing of said spectacle lens is regarded as a y 2 -axis, and a direction which is perpendicular to the y 2 -axis and the z 2 -axis in the left hand coordinate system is regarded as an x 2 -axis, the coordinate (h,θ) of the inner surface is defined as a point having a height h (unit: mm) from the z 2 -axis on an intersection line which is formed between the inner surface and a plane including the z 2 -axis and forming an angle θ (unit: degree) with respect to the x 2 -axis, wherein the centration point being defined as a point which coincides with a pupil position of a wearer when said spectacle lens is viewed from a front side in a state of wearing of said spectacle lens.