Apodized diffractive IOL with frustrated diffractive region
View Patent ↗In one aspect, the present invention provides a diffractive ophthalmic lens (e.g., a diffractive IOL) that includes an optic having an anterior surface and a posterior surface, where the optic provides a far focus. A frustrated diffractive structure comprising a plurality of diffractive zones is disposed on at least one of those surfaces so as to provide a near focus. Each zone is separated from an adjacent zone by a zone boundary that imparts an optical delay to the incident light. Further, at least two consecutive zone boundaries are configured such that a difference between their associated phase delays for at least one wavelength of the incident light is greater than about ¼ wavelength so as to direct a portion of the incident light to a location between the near and far foci.
1. An ophthalmic lens, comprising
an optic having an anterior surface and a posterior surface,
a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces, each zone being separated from an adjacent zone by a zone boundary,
said optic providing a far focus corresponding to a zeroth diffraction order of said diffractive zones and a near focus corresponding to a 1 st diffraction order of said diffractive zones,
wherein said zone boundaries are characterized by a plurality of non-uniform step heights generating non-uniform phase delays adapted to direct a portion of incident light to a location between said near and far foci so as to enhance intermediate vision.
2. The lens of claim 1 , wherein said non-uniform step heights comprise at least two consecutive steps each imparting a phase delay to incident light such that a difference between the phase delays associated with said consecutive steps for at least one wavelength of the incident light is greater than about
1
20
wavelength.
3. The lens of claim 2 , wherein said optic provides a far-focus optical power in a range of about 6 D to about 34 D.
4. The lens of claim 2 , wherein said optic provides a near-focus optical power corresponding to an add power in a range of about 2 D to about 4 D.
5. The lens of claim 1 , wherein said diffractive zones are surrounded by a portion of the respective surface that lacks diffractive elements.
6. An ophthalmic lens, comprising
an optic having an anterior surface and a posterior surface, said optic providing a far-focus optical power; and
a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces for providing a near-focus optical power,
wherein at least two of said diffractive zones exhibit sufficiently different surface curvatures so as to cause a portion of light incident on said optic to be directed to an intermediate location between said near and far foci for enhancing intermediate vision and wherein a difference in the curvatures of said at least two diffractive zones is in a range of about 10% to about 50%.
7. An ophthalmic lens, comprising:
an optic having an anterior surface and a posterior surface, said optic providing a far-focus optical power; and
a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces for providing a near-focus optical power, wherein:
at least two of said diffractive zones exhibit sufficiently different surface curvatures so as to cause a portion of light incident on said optic to be directed to an intermediate location between said near and far foci for enhancing intermediate vision;
a difference in the curvatures of said at least two diffractive zones is in a range of about 10% to about 50%; and
said at least two diffractive zones comprise two adjacent zones.
8. An ophthalmic lens, comprising
an optic having an anterior surface and a posterior surface, said optic providing a far-focus optical power; and
a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces for providing a near-focus optical power,
wherein at least two of said diffractive zones exhibit sufficiently different surface curvatures so as to cause a portion of light incident on said optic to be directed to an intermediate location between said near and far foci for enhancing intermediate vision, and wherein said near-focus optical power corresponds to an add power in a range of about 2 D to about 4 D.
9. An ophthalmic lens, comprising
an optic having an anterior surface and a posterior surface, said optic providing a far focus,
a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces for providing a near focus,
wherein a surface of at least one of said diffractive zones exhibits an asphericity such that said diffractive structure directs at least a portion of incident light to an intermediate location between said near and far foci, wherein said asphericity is characterized by a conic constant in a range of about −10 to about −1000.
10. The lens of claim 9 , wherein said ophthalmic lens comprises an IOL.
11. An ophthalmic lens, comprising
an optic having an anterior surface and a posterior surface, said optic providing a far focus,
a diffractive structure comprising a plurality of diffractive zones disposed on at least one of said surfaces for providing a near focus, wherein said near focus is characterized by an add power in a range of about 2 D to about 4 D,
wherein a surface of at least one of said diffractive zones exhibits an asphericity such that said diffractive structure directs at least a portion of incident light to an intermediate location between said near and far foci.
12. The lens of claim 11 , wherein said ophthalmic lens comprises an IOL.
13. An ophthalmic lens, comprising
an optic having an anterior optical surface and a posterior optical surface, said optic providing a far focus,
a plurality of annular diffractive zones disposed on one of said surfaces about an optical axis of said optic so as to provide a near focus,
wherein at least one of said zones (i) has a boundary with a radial location defined by the following relation:
r i 2 =r 0 2 +2 iλf
wherein
i denotes the zone number (i=0 denotes the central zone),
λ denotes a design wavelength,
f denotes a focal length of the near focus, and
r 0 denotes the radius of the central zone, and
wherein at least another zone has a boundary with a radial location that differs sufficiently from that defined by the above relation for a putative respective zone so as to direct a portion of incident light to an intermediate location between said far and near foci.
14. The lens of claim 13 , wherein the radial location of said at least another zone differs from that defined by said relation by a factor in a range of about 20% to about 50%.
15. The lens of claim 13 , wherein λ is in a range of about 400 nm to about 700 nm.
16. The lens of claim 13 , wherein said near focus corresponds to an add power in a range of about 2 D to about 4 D.
17. An ophthalmic lens, comprising
an optic having an anterior optical surface and a posterior optical surface, said optic providing a far focus,
a plurality of diffractive zones disposed on at least one of said surfaces to provide a near focus,
wherein said zones comprise a central zone having a radius that is sufficiently different from √{square root over (λf)}, where λ denotes a design wavelength and f denotes a focal length of the near focus, such that at least a portion of incident light is directed to an intermediate location between said near and far foci.
18. The lens of claim 17 , wherein λ is in a range of about 400 nm to about 700 nm.
19. The lens of claim 17 , wherein said near focus corresponds to an add power in a range of about 2 D to about 4 D.