Multifocal diffractive ophthalmic lens using suppressed diffractive order

1. A multifocal ophthalmic lens, comprising:

an ophthalmic lens having a base curvature corresponding to a base power; and

a diffractive element, the diffractive element producing constructive interference in at least four consecutive diffractive orders corresponding a range of vision between near and distance vision, wherein the constructive interference produces a near focus, a distance focus corresponding to the base power of the ophthalmic lens, and an intermediate focus between the near focus and the distance focus and wherein a diffraction efficiency of at least one of the diffractive orders is suppressed to less than ten percent.

2. The lens of claim 1 , wherein the lens is an intraocular lens (IOL).

3. The lens of claim 2 , wherein the IOL is a posterior chamber IOL.

4. The lens of claim 3 , wherein the posterior chamber IOL is configured to be implanted in a capsular bag.

5. The lens of claim 1 , wherein the at least four consecutive orders are (0, +1, +2, +3).

6. The lens of claim 5 , wherein the +1 order is suppressed.

7. The lens of claim 1 , wherein the near focus corresponds to vision at 40 cm, and the intermediate focus corresponds to vision at 60 cm.

8. The lens of claim 1 , wherein the diffractive element comprises a plurality of annular diffractive steps.

9. The lens of claim 1 , wherein the diffractive steps have a corresponding step height relative to the base curvature of the ophthalmic lens at consecutive radial step boundaries as follows:

y

i

=

A

i

x

i

-

x

i

-

1

⁢

(

x

-

x

i

-

1

)

+

ϕ

i

⁢

⁢

(

i

=

1

,

2

,

3

)

wherein A i is the corresponding step height relative to the base curvature (base optical power) of the base lens, y i is the sag in the corresponding segment (height above or below the x-axis), φ i is the relative phase delay from the x-axis, and x i is the position of the step along the x-axis.