Monocentric bifocal contact lens

Claim 1

A bifocal contact lens comprising: a first generally circular main lens segment of concavo-convex form in section made from low index resinous material and shaped and dimensioned to be maintained upon the eye of the wearer with the concave surface conforming to the cornea of the eye such that the main lens segment replaces the natural cornea as a corneal surface and such that the optical center of said main lens segment is normally positioned in the region of the central pupil area of the eye of the wearer, a smaller second crescent-shaped lens segment of concavo-convex form in section made from high index resinous material with a shorter focal length than said first main lens segment for near vision and embedded in the posterior concave surface of said first main lens segment, the optical center of said second lens segment being at the midpoint of the curved upwardly arched upper edge thereof and coincident with the optical center of said first main lens segment to provide a monocentric bifocal construction, the curved lower and side edges of said second lens segment being generally concentric with the generally circular outline of said first main lens segment, said lens when normally positioned on the eye providing for simultaneous distance and near vision through the first and second lens segments respectively, and the overlapping distance and near vision images formed on the eye retina in the region aligned with the coincident optical centers of the first and second lens segments producing a vertical gradient focus visual effect without displacement of the retinal image.