1. A trifocal contact lens to be worn on the cornea of a human eye, comprising: a lens body of circular configuration; said lens body being formed of first plastic material of a high index of refraction on the frontal portion thereof for far point vision and a second plastic material of a low index of refraction fused on the rearward portion of said first material for near point vision and intermediate vision, said lens having an anterior convex surface and a posterior concave surface; a posterior portion of said first material having two generally concave curvatures, one of said concave curvatures being related to the intermediate vision and shorter in radius than the other of said concave curvatures which is more nearly located at the periphery of the lens and which is related to near point vision; and an anterior portion of said second material conforming With said posterior portion of said first material to form two interface junctions having radii of curvature ranging from 7.30 mm. to 14.00 mm., said posterior curved surface related to the cornea of the eye for proper fitting purposes, the dual interface curvatures being positioned with respect to the steep posterior surface curvature to insure the presence of the intermediate zone in the final lens, the radius of curvature of said posterior curved surface being shorter than that of said interface junctions and extending through the center interface junction leaving a curved area of only high index material near the center area of the lens to provide the proper power for said far point or distant vision, and leaving said high index material in front of said low index material toward the periphery of the lens so that said low index material forms an area radially spaced from said far point vision area at the central portion of the lens, the centers of curvature of said anterior convex surface, said posterior concave surface and said two interface junctions being in eccentric relationship to locate the intermediate and near point vision areas below the far point vision area occupying the central and upper portion of the lens, and providing the lens with a thin upper edge and a relatively thick lower edge for gravitational orientation when worn on the cornea of the human eye.