Progressive multifocal lens.

摘要

In a progressive multifocal lens of the present invention, the horizontal sectional shape of a refracting surface of the lower portion of a farsight portion defines a non-circular arc in which a horizontal section curvature is increased and then decreased as being away from an intersecting point with the principal meridional curve along a horizontal crossing curve, the horizontal sectional shape of a refracting surface of the upper portion of a nearsight portion defines a non-circular arc in which a horizontal section curvature is decreased and then made approximately constant as being away from an intersecting point with the meridional curve along a horizontal crossing curve, the gradient of the decrease of a horizontal section curvature is approximately constant from the upper portion of the nearsight portion to the lower portion thereof, the horizontal sectional shape of a refracting surface of the center of an intermediate portion in which a horizontal section curvature is decreased as being away from an intersecting point with the principal meridional curve along a horizontal crossing curve, and the gradient of the decrease of a horizontal section curvature is increased as approaching the nearsight portion from the center of the intermediate portion. <IMAGE>