Toric intraocular lens with modified power characteristics

1. A toric ophthalmic lens comprising an optic, the optic comprised of an anterior surface and a posterior surface with toric features on either the posterior or anterior surface, the toric features comprised of meridians, including a high power meridian and a low power meridian orthogonal to the high power meridian, with at least one radially modulated meridian along which power monotonically varies in a stepwise manner with increasing radial position.

2. The toric ophthalmic lens of claim 1 , wherein the power along the at least one radially modulated meridian monotonically decreases with increasing radial position.

3. The toric ophthalmic lens of claim 1 , wherein the power along the at least one radially modulated meridian monotonically increases with increasing radial position.

4. The toric ophthalmic lens of claim 1 , wherein the power along the at least one radially modulated meridian monotonically decreases, with increasing radial position, to zero.

5. The toric ophthalmic lens of claim 4 , wherein the power along the at least one radially modulated meridian reaches zero at a radial position inside a periphery of the optical element.

6. The toric ophthalmic lens of claim 1 , further comprising a diffraction grating, wherein the diffraction grating provides a first focus point and a second focus point.

7. The toric ophthalmic lens of claim 1 , wherein along the high power meridian, the integral of power times radius squared is equal to the nominal power times the area of a clear aperture of the optical element.

8. A toric ophthalmic lens comprising an optic, the optic comprised of an anterior surface and a posterior surface with toric features on either the posterior or anterior surface, the toric features having meridians associated therewith, including a high power meridian and a low power meridian orthogonal to the high power meridian, wherein along the high power meridian:

between an originating position and a respective first radial position, power equals a respective nominal power;

between the respective first radial position and a respective second radial position, power is greater than the respective nominal power; and

between the respective second radial position and a respective third radial position, power is less than the respective nominal power;

wherein the power between the originating position and the respective third radial position monotonically varies in a stepwise manner.

9. The toric ophthalmic lens of claim 8 , wherein between the respective first radial position and the respective second radial position, the power equals an overcorrection power.

10. The toric ophthalmic lens of claim 9 , wherein the overcorrection power exceeds the nominal power by no more than 1.5 diopters.

11. The toric ophthalmic lens of claim 8 , wherein between the respective second radial position and the respective third radial position, the power equals an undercorrection power.

12. The toric ophthalmic lens of claim 11 , wherein the nominal power exceeds the undercorrection power by no more than 1.5 diopters.

13. The toric ophthalmic lens of claim 8 , wherein along the high power meridian, the integral of power times radius squared is equal to the nominal power times the area of a clear aperture of the optical element.

14. The toric ophthalmic lens of claim 8 , wherein the optical element comprises a diffraction grating.

15. A method of manufacturing a toric ophthalmic lens having meridians associated therewith, including a reference meridian, a high power meridian, and a low power meridian orthogonal to the high power meridian, the method comprising:

providing a standard toric lens function that defines power such that each meridian corresponds to a respective constant power;

applying a modification function to the standard toric lens function to obtain a modified toric lens function, wherein the modification function is a function of radial position and angle position relative to the reference meridian, and wherein the modified toric lens function results in non-constant power along at least one meridian; wherein the non-constant power monotonically varies in a stepwise manner with increasing radial position; and

fabricating the toric ophthalmic lens in accordance with the modified toric lens function.

16. The method of claim 15 , wherein the power along the at least one radially modified meridian monotonically decreases with increasing radial position.

17. The method of claim 15 , wherein the power along the at least one radially modified meridian monotonically increases with increasing radial position.

18. The method of claim 15 , wherein the modified tonic lens function results in radially modified meridians along which power varies with increasing radial position, and for each radially modified meridian:

between an originating position and a respective first radial position, the power equals a respective nominal power;

between the respective first radial position and a respective second radial position, the power is greater than the respective nominal power; and

between the respective second radial position and a respective third radial position, the power is less than the respective nominal power.

19. The method of claim 18 , wherein:

between the respective first radial position and the respective second radial position, the power equals an overcorrection power; and

between the respective second radial position and the respective third radial position, the power equals an undercorrection power.

20. The method of claim 15 , wherein fabricating the toric ophthalmic lens comprises the step of creating a diffraction grating.