Patent ID: 6354704
Filing Date: 2002-03-12
Classification: G02C

Abstract:
A progressive power spectacle lens, including:a distance portion having a dioptric power for distance vision; a near portion having a dioptric power for near vision; and an intermediate portion having a progressive dioptric power for vision at ranges intermediate between the distance and near portions; wherein a predetermined surface astigmatism is provided on a main meridian, the surface astigmatism decreasing and then increasing as the distance from the main meridian increases in a horizontal direction within said near portion, wherein the variation of said surface astigmatism satisfies the condition (1) on at least one point in the range of âˆ’30(1) AS(Xm,Y)>0.2, and (2) AS(Xm,Y)âˆ’AS(X, Y)>0.05, where AS(X,Y) is the surface astigmatism at the point (x,y), and Xm is a displacement of the main meridian from the Y-axis defined by Xm=f(Y).