Ophthalmic lenses with diffractive power

Abstract

A contact or spectacle or implant lens has positive diffractive power which introduces negative longitudinal chromatic aberration that more than counteracts, and is preferably greater than twice, the natural positive longitudinal chromatic aberration of the eye. The residual negative longitudinal chromatic aberration enables the eye/brain system to perform tasks by concentrating on the appropriate color component at the different respective distances without need to accommodate.

Dependencies are inferred from the claim text.