Patent ID: 9417462
Filing Date: 2016-08-16
CPC Classification: G02C

Claim Text:
1. A method of designing a progressive power lens for spectacles that has a distance portion and a near portion of different average prescription powers, wherein the progressive power lens includes a surface power OHPf in a horizontal direction and a surface power OVPf in a vertical direction of the distance portion on an object-side surface along a principal meridian or a vertical reference line passing through a fitting point; and a surface power OHPn in a horizontal direction and a surface power OVPn in a vertical direction of the near portion on the object-side surface along the principal meridian or the vertical reference line, the object-side surface includes at least one of a toric surface with the surface power OHPf greater than the surface power OVPf and a toric surface with the surface power OHPn greater than the surface power OVPn, and the eyeball-side surface along the principal meridian or the vertical reference line includes a surface having a power such that it provides cancel shifts in the surface power provided by the toric surface on the object-side surface, the method comprises: selecting a spectacle specification including a first condition, wherein the average prescription power of the distance portion is plus and the value thereof is at least 3.0 D; or selecting a spectacle specification including a second condition, wherein the average prescription power of the distance portion is minus and the absolute value thereof is at least 3.0 D, wherein the first condition includes a condition that the surface power OVPf is greater than the surface power OVPn, the second condition includes a condition that the surface power OVPf is smaller than the surface power OVPn, and D is dioptre.