Truncated diffractive intraocular lenses

• US 20070171362A1
• Filed: 08/23/2006
• Published: 07/26/2007
• Est. Priority Date: 12/01/2004
• Status: Abandoned Application

• Current Assignee: Alcon Incorporated
• Original Assignee: Alcon Incorporated
• Inventors: Zhang, Xiaoxiao, Karakelle, Mutlu, Xie, Jihong, Hong, Xin, Simpson, Michael, Vannoy, Steve
• Application Number:
  US11/444,112
• Publication Number:
  US 20070171362A1
• Time in Patent Office: Days
• US Class Current: 351/177
• CPC Class Codes: A61F 2/1618 Multifocal lenses
• CPC Class Codes: A61F 2/1654 Diffractive lenses
• CPC Class Codes: G02C 2202/20 Diffractive and Fresnel lenses or lens portions
• CPC Class Codes: G02C 7/042 Simultaneous type
• CPC Class Codes: G02C 7/044 Annular configuration, e.g. pupil tuned

Abstract

In one aspect, the present invention provides a method of designing a diffractive ophthalmic lens (e.g., an intraocular lens (IOL)) that includes providing an optic having an anterior refractive surface and a posterior refractive surface, wherein the optic provides a far-focus power (e.g., in a range of about 18 to about 26 Diopters (D)). A truncated diffractive structure can be disposed on at least one of the surfaces for generating a near-focus add power (e.g., in a range of about 3 D to about 4 D). And the diffractive structure can be adjusted so as to obtain a desired distribution of optical energy between the near and far foci for a range of pupil sizes.

Claims

1. A method of designing a diffractive ophthalmic lens, comprising

providing an optic having an anterior refractive surface and a posterior refractive surface, said optic providing a far-focus power,

disposing a truncated diffractive structure on one of said surfaces for generating a near-focus add power,

adjusting the diffractive structure so as to obtain a desired distribution of optical energy between said near and far foci for a range of pupil sizes.

2. The method of claim 1, wherein the step of adjusting the diffractive structure comprises selecting a diameter of said structure.

3. The method of claim 1, wherein said diffractive structure comprises a plurality of diffractive zones exhibiting apodized step heights at boundaries thereof.

4. The method of claim 3, wherein the step of adjusting the diffractive structure comprises selecting a number of the diffractive zones.

5. The method of claim 3, wherein the step of adjusting the diffractive structure comprises selecting a variation of the step heights at the zone boundaries.

6. The method of claim 1, wherein said far-focus power is in a range of about 16 D Diopters to about 28 Diopters.

7. The method of claim 5, wherein said near-focus add power is in a range of about 3 Diopters to about 4 Diopters.

8. The method of claim 1, wherein the step of adjusting the diffractive structure comprises selecting the diffractive structure so as to obtain a desired shift in a ratio of optical energy in the far-focus relative to energy in the near-focus as the pupil size varies over a pre-defined range.

9. The method of claim 1, wherein said ophthalmic lens comprises an intraocular lens.

10. The method of claim 1, wherein said ophthalmic lens comprises a contact lens.

11. A method of designing an ophthalmic lens, comprising

providing an optic exhibiting a far focus and a near focus, said optic having a diffractive structure on at least one surface thereof for generating the near focus, and

adjusting the diffractive structure so as to obtain a desired distribution of optical energy between said far and near foci over a range of pupil sizes based on visual needs of a patient population.

12. The method of claim 11, further comprising adjusting the diffractive structure to obtain the desired energy distribution at a design wavelength.

13. The method of claim 12, wherein said design wavelength is selected to be about 550 nm.

14. The method of claim 11, wherein said patient population comprises patients having pupil diameters in a range of about 2 mm to about 5 mm under photopic conditions.

15. The method of claim 11, wherein said patient population favors far vision over near vision.

16. The method of claim 11, wherein said patient population favors near vision over far vision.

17. The method of claim 11, wherein adjusting the diffractive structure comprises selecting a number of diffractive zones comprising that structure.

18. The method of claim 11, wherein adjusting the diffractive structure comprises selecting a variation of step heights at boundaries of a plurality of diffractive zones comprising the diffractive structure.

19. The method of claim 11, wherein adjusting the diffractive structure comprises selecting a phase delay generated by the structure at a center thereof.

20. A method of correcting vision of a patient, comprising

providing an optic exhibiting a far-focus power and a near focus power for correcting vision in one eye of the patient,

providing another optic exhibiting a far-focus power and a near focus power for correcting vision in the other eye of the patient,

wherein said optics have substantially similar far-focus power and different near-focus power.

21. The method of claim 20, further comprising selecting said far-focus power to be in a range of about 16 Diopters to about 28 Diopters.

22. The method of claim 21, wherein each optic provides a near-focus add power in a range of about 2.5 to about 4 Diopters.

23. The method of claim 22, wherein one optic provides a near-focus add power of about 4 D and the other optic provides a near-focus add power of about 3 D.

24. The method of claim 22, wherein one optic provides a near-focus add power of about 4 D and the other optic provides a near-focus add power of about 3.25 D.

25. The method of claim 22, wherein one optic provides a near-focus add power of about 4 D and the other optic provides a near-focus add power of about 3.5 D.

26. The method of claim 22, wherein one optic provides a near-focus add power of about 4 D and the other optic provides a near-focus add power of about 3.75 D.

27. The method of claim 20, wherein each optic comprises a diffractive structure disposed on a surface thereof for generating said far and near focus power.

28. An ophthalmic lens, comprising

an optic having an anterior surface and a posterior surface,

a diffractive structure disposed on at least one of said surfaces,

said diffractive structure comprising a plurality of diffractive zones separated from one another by a plurality of steps having decreasing heights as a function of radial distance from an apex of said surface,

wherein said step heights are defined in accordance with the following relation:

$h=\frac{b*\mathrm{\lambda <br><br>}}{\left(n_2-n_1\right)}$

wherein

h represents the physical step height,

λ

denotes the design wavelength,

n₁ denotes the refractive index of a medium surrounding the lens,

n₂ denotes the refractive index of the material forming the lens, and

b is defined in accordance with the following relation;

$b=\frac{\mathrm{phas}<br><br>\text{\hspace{1em}<br><br>}<br><br>0}{{\left(1+\frac{r}{\mathrm{rcontrol}}\right)}^{\mathrm{rolloff}}},$

wherein

b represents the phase delay as a fraction of 2π

,

phase0 represents the overall (cumulative) optical phase delay across the diffractive steps,

r_control represents the overall extend of the apodization region,

rolloff defines the steepness of the slope of the apodization profile.

29. The ophthalmic lens of claim 28, wherein

Phase0 can be in a range of about 0.4 to about 0.7,

r_control can be in a range of about 1 to about 2, and

rolloff can be in a range of about 5 to about 200.

30. The ophthalmic lens of claim 28, wherein at least one of said anterior or posterior surfaces includes an aspherical base profile.

31. The ophthalmic lens of claim 30, wherein said profile is characterized by a conic constant in a range of about −

10 to about −

1000.

32. The ophthalmic lens of claim 30, wherein said base profile is defined by the following relation:

33. The ophthalmic lens of claim 28, wherein at least one of said anterior or posterior surfaces exhibits a toric base profile.

34. An ophthalmic lens, comprising

an optic comprising an anterior surface and a posterior surface,

a diffractive structure disposed on a central portion of one of said surfaces surrounded by a peripheral portion of the surface that is devoid of diffractive structures,

wherein one of said peripheral or central portions is characterized by a spherical base profile and the other portion is characterized by an aspherical base profile.

35. The ophthalmic lens of claim 34, wherein said ophthalmic lens comprises an IOL.

36. An ophthalmic lens, comprising

an optic having an anterior surface and a posterior surface, and

a truncated diffractive structure disposed on a portion of one of said surfaces, said diffractive structure being characterized by a plurality of diffractive zones separated from one another by substantially uniform step heights,

wherein at least one of said surfaces exhibits a toric base profile.

37. The ophthalmic lens of claim 36, wherein said ophthalmic lens comprises an IOL.