Patent ID: 8668332

Claim:
A toric contact lens, comprising: a convex-shaped lens front surface and a concave-shaped lens back surface; and a prism ballast structure in which a thickness is gradually increased from a lens upper end portion to a lens lower end portion, wherein a center optical area determining a refractive degree, an annular transition area surrounding the center optical area, and an annular peripheral area surrounding the transition area are defined on the lens front surface, and a shape of the lens front surface has a mirror image symmetry with respect to a vertical radial line as a boundary from the lens upper end portion to the lens lower end portion passing through a lens middle point, two maximum thickness portions where the lens thickness becomes maximum are formed on a lower side of the lens middle point of the lens front surface, a valley-shaped recess in such a manner that the thickness is smoothly decreased between the two maximum thickness portions is formed toward the lens lower end portion, and a width of the valley-shaped recess in a horizontal direction is narrowed toward the lens lower end portion.