PURPOSE: To form a soft contact lens having an aspherical front face which can be worked accurately and reproduciably by expressing the degree of asphericity of the front face by a specific function in polar coordinates.

CONSTITUTION: In the dehydrated state, the degree of asphericity of the front face of the contact lens made of plastics is expressed in polar coordinates by a function (n) f[sin(a)] where (a) is the angle to the polar axis and (n) indicates the degree of eccentricity of a circular or arcuate control face used for working of the front face. The aspherical face obtained in this manner simulates an aspherical face of the Evans patent up to a considerable degree, and especially, the degree (n) of eccentricity is a sufficiently large value and can be set accurately and reproducibly.