Patent ID: 7762663

Claim:
A spectacle lens design method for designing a spectacle lens attached to a spectacle frame having a bend angle of 200 degrees or larger, comprising: setting a distance portion, a near portion having power different from power of the distance portion, and a progressive portion which is disposed between the distance portion and the near portion and has power progressively varying on at least either an object side refractive surface or an eyeball side refractive surface included in the spectacle lens; adding astigmatic power for canceling aberration produced by the bend angle of the spectacle frame at a design reference point of the distance portion to the entire distance portion and astigmatic power for canceling aberration produced by the bend angle of the spectacle frame at a design reference point of the near portion to the entire near portion on either the object side refractive surface or the eyeball side refractive surface of the spectacle lens; determining an aspherical surface addition quantity which provides the optimum optical properties throughout the object side refractive surface or the eyeball side refractive surface of the spectacle lens; and adding prismatic power for canceling prismatic power produced by the bend angle of the spectacle frame at the design reference point of the distance portion to the entire distance portion and prismatic power for canceling prismatic power produced by the bend angle of the spectacle frame at the design reference point of the near portion to the entire near portion on either the object side refractive surface or the eyeball side refractive surface of the spectacle lens; wherein the aspherical surface addition quantity determining step determines the aspherical surface addition quantity by setting a plurality of reference lines extending radially from a geometrical center of the spectacle lens through the distance portion of the spectacle lens to the edge of the spectacle lens and a plurality of reference lines extending through the near portion of the spectacle lens to the edge of the spectacle lens, calculating aspherical surface addition quantities providing the optimum optical properties on the respective reference lines, and calculating aspherical surface addition quantities for areas between the reference lines by interpolation.