Patent ID: 7063422

Claim:
A contact lens, comprising an anterior surface and an opposite posterior surface, wherein at least one of the anterior and posterior surface includes a vertical meridian, a horizontal meridian, and a central optical zone, wherein the central optical zone has a top boundary, a bottom boundary, a distance vision zone and a rotationally-asymmetrical progressive zone adjacent to the distance vision zone, wherein the distance vision zone is located in the upper portion of the central optical zone and provides a distance power for distance vision correction, wherein the rotationally-asymmetrical progressive zone is located in the lower portion of the central optical zone and provides a variable intermediate vision correction and near vision correction, wherein the rotationally-asymmetrical progressive zone has a surface that provides a power addition profile, along the upper vertically radiating semi-meridian, which is defined by two or more linear functions of equation (1) or by equation (2) or equation { p ⁡ ( x ) = b 1 + k 1 ⁢ x ⁢ 0 ≤ x < x 1 p ⁡ ( x ) = b 2 + k 2 ⁢ x ⁢ x 1 ≤ x < x 2 ⋮ p ⁡ ( x ) = b i + k i ⁢ x ⁢ x i - 1 ≤ x < x i ⋮ ( 1 ) p ⁡ ( x ) = A 2 · cos ⁡ ( x X o ⁢ π ) + A 2 ( 2 ) p ⁡ ( x ) = A · [ 1 - ( x X 0 ) n ] ( 3 ) in which p(x) is an added power at a radial distance of x from the radial center; b i is a coefficient which is the intercept of a linear line; k i is the rate of change of the added power as function of the distance from the radial center; A is the maximum added power; X o is a radial distance between the radial center and the optical axis; and n is any number which can be an integer or non-integer larger than 1 but smaller than or equal to 10.