US Patent 7441894 Pseudo-accommodative IOL having diffractive zones with varying areas

In one aspect of the invention, a trifocal ophthalmic lens is disclosed that includes an optic having at least one optical surface, and a plurality of diffractive zones that are disposed on a portion of that surface about an optical axis of the optic. At least two of those diffractive zones have different areas so as to cause broadening of optical energy profiles at a near and a far foci of the diffractive zones for generating an intermediate focus.