Lens surface with combined diffractive, toric, and aspheric components

The present invention is directed generally to ophthalmic lenses, and more particularly, to diffractive ophthalmic lenses that provide compensation for multiple aberrations.

Intraocular lenses (IOLs) are routinely implanted in patients\' eyes during cataract surgery to replace the natural crystalline lens. In some cases, an IOL can include diffractive structures so as to have not only a far-focus power but also a near-focus power, thereby providing a degree of pseudoaccommodation. A variety of aberrations, such as spherical and astigmatic aberrations, can adversely affect the optical performance of such lenses. For example, spherical aberrations can degrade vision contrast, especially for large pupil sizes.

Diffractive IOLs that provide compensation for multiple aberrations are known. However, the fabrication of such IOLs can be time-consuming and expensive.

Accordingly, there is a need for improved ophthalmic lenses, and particularly for improved diffractive IOLs that can be more readily fabricated.

The present invention relates generally to diffractive ophthalmic lenses, such as intraocular lenses (IOLs), that provide compensation for aspheric and astigmatic aberrations. In some embodiments, a single surface of the lens is shaped to include not only a plurality of diffractive structures but also a base profile that exhibits a combination of asphericity and toricity.

In one aspect, an intraocular lens (IOL) is disclosed that includes an optic comprising an anterior surface and a posterior surface, and a plurality of diffractive zones disposed on one of said surfaces (e.g., the anterior surface). The surface having the diffractive zones exhibits a base profile characterized by a combination of asphericity and toricity.

In a related aspect, the optic provides a far-focus power, e.g., in a range of about 16 to about 32 Diopters (D), as well as a near-focus power characterized, e.g., by an add power in a range of about 1 D to about 6 D.

In another aspect, a profile of the surface having the diffractive zones can be defined in accordance with the following relation:

sag(R_avrg,r,θ)=diffractive(R_avrg,r)+toric(R_avrg,r,θ)+asph(R_avrg,r)

wherein,
sag indicates the sag of the surface along the optical axis (e.g., z-axis) at a radial distance r from the center of the surface (intersection of the optical axis with the surface) and at a meridian angle θ, where R_avrg represents the base radius of curvature of average meridian (i.e., 45°), and diffractive (R_avrg,r), toric(R_avrg,r,θ) and apsh(R_avrg,r) represent, respectively, the diffractive, toric and aspheric components of the surface profile.

In a related aspect, the diffractive component, i.e., diffractive (R_avrg,r), of the surface profile can be defined as follows:

diffractive(R_avrg,r)=z=z_rad−√{square root over (R_rad²−r²)}