Multifocal lens having reduced visual disturbances

1. An ophthalmic lens comprising:

an anterior surface having an anterior surface base curvature;

a posterior surface having a posterior surface base curvature, wherein the anterior surface base curvature and the posterior surface base curvature are adapted to provide a base power defining a first focus corresponding to a first focal length and a first spherical aberration corresponding to the first focus; and

a diffractive structure disposed on one of the anterior surface and the posterior surface, the diffractive structure adapted to:

split light between the first focus corresponding to the first focal length and a second focus corresponding to a second focal length; and

provide a second spherical aberration corresponding to the second focus, the second spherical aberration having an opposite sign relative to the first spherical aberration;

wherein the first spherical aberration has a first magnitude and the second spherical aberration has a second magnitude greater than the first magnitude.

2. The ophthalmic lens of claim 1 , wherein the diffractive structure includes a first diffractive order for the first focus and a second diffractive order for the second focus.

3. The ophthalmic lens of claim 2 wherein the first diffractive order is the 0th order and the second diffractive order is the 1st order.

4. The ophthalmic lens of claim 1 wherein the first spherical aberration is a negative spherical aberration and the second spherical aberration is a positive spherical aberration.

5. The ophthalmic lens of claim 1 , wherein the first focus corresponds to distance vision and the second focus corresponds to near vision.

6. The ophthalmic lens of claim 1 , wherein:

the first focus is associated with a first intensity peak of an energy profile of the ophthalmic lens;

the second focus is associated with a second intensity peak of the energy profile of the ophthalmic lens; and

the first spherical aberration extends the first intensity peak asymmetrically toward the second intensity peak.

7. The ophthalmic lens of claim 1 , wherein:

the first focus is associated with a first intensity peak of an energy profile of the ophthalmic lens;

the second focus is associated with a second intensity peak of an energy profile of the ophthalmic lens; and

the second spherical aberration extends the second intensity peak asymmetrically toward the first intensity peak.

8. The ophthalmic lens of claim 6 , wherein the second spherical aberration extends the second intensity peak asymmetrically toward the first intensity peak.

9. The ophthalmic lens of claim 1 , wherein the diffractive structure is adapted to split light between the first focus corresponding to the first focal length, the second focus corresponding to the second focal length, and a third focus corresponding to an intermediate focal length is between the first focal length and the second focal length.

10. The ophthalmic lens of claim 9 , wherein:

the diffractive structure provides a third spherical aberration corresponding to the third focus; and

a magnitude of the third spherical aberration is less than the magnitude of the second spherical aberration.

11. The ophthalmic lens of claim 9 , wherein:

the first focus is associated with a first intensity peak of an energy profile of the ophthalmic lens;

the second focus is associated with a second intensity peak of the energy profile of the ophthalmic lens;

the first spherical aberration extends the first intensity peak asymmetrically toward the second intensity peak; and

the second spherical aberration extends the second intensity peak asymmetrically toward the first intensity peak.

12. The ophthalmic lens of claim 1 wherein the ophthalmic lens is one of an intraocular lens and a contact lens.

13. An intraocular lens comprising:

an anterior surface having an anterior surface base curvature and a posterior surface having a posterior surface base curvature, the anterior surface base curvature and the posterior surface base curvature collectively disposed to provide:

a base power defining a far focus corresponding to a first focal length; and

a negative spherical aberration corresponding to the far focus and having a first magnitude; and

a diffractive structure disposed on one of the anterior surface and the posterior surface, the diffractive structure disposed to:

distribute light between the far focus corresponding to the first focal lengths and a near focus corresponding to a second focal length; and

provide a positive spherical aberration corresponding to the near focus, the positive spherical aberration having a second magnitude greater than the first magnitude of the negative spherical aberration.

14. The ophthalmic lens of claim 13 , wherein:

the far focus is associated with a first intensity peak of an energy profile of the ophthalmic lens;

the near focus is associated with a second intensity peak of the energy profile of the ophthalmic lens;

the negative spherical aberration extends the first intensity peak asymmetrically toward the second intensity peak; and

the positive spherical aberration extends the second intensity peak asymmetrically toward the first intensity peak.

15. The ophthalmic lens of claim 14 , wherein the diffractive structure is further adapted to distribute light to an intermediate focus between the far focus and the near focus.

16. The ophthalmic lens of claim 15 , wherein:

the diffractive structure provides a third spherical aberration corresponding to the intermediate focus;

the sign of the third spherical aberration is positive; and

the third spherical aberration has a third magnitude, the third magnitude being less than the second magnitude.