Patent ID: 6595638
Filing Date: 2003-07-22
Classification: G02C

Abstract:
A progressive multifocal ophthalmic lens comprising an aspherical surface with at every point thereon a mean sphere (S) and a cylinder (C), a far vision region, an intermediate vision region and a near vision region, a main meridian of progression passing through said three regions, a power addition equal to a difference in mean sphere between a near vision region control point and a far vision region control point, a progression length less than 12 mm, progression length being equal to the vertical distance between a mounting center and a point on said meridian where mean sphere is greater than mean sphere at the far vision control point by 85% of the power addition value, in which the ratio betweenfirstly, the product of cylinder times the norm of sphere gradient, and secondly, the square of power addition is less than 0.08 mmâˆ’1 at every point within a 40 mm diameter disc centered on the center of the lens, and in which cylinder within that part of said disc situated above the mounting center is less than 0.5 times power addition.