Ophthalmic lens, systems and methods with angular varying phase delay
An ophthalmic lens, such as an intraocular lens (IOL), a phakic IOL or a corneal implant, and a system and method relating to same, having coupled thereto one or more rotationally asymmetric and/or non-continuous diffractive zones, such as for providing improved multifocal vision correction.
1. An ophthalmic lens, comprising:
an anterior face and a posterior face, the faces disposed about an optical axis;
at least one diffractive region imposed on the anterior face or the posterior face, comprising a plurality of diffractive echelettes with stepheights that cause a phase delay, wherein the stepheights of each echelette vary tangentially as a function of rotational angle and wherein the phase delay varies tangentially as a function of rotational angle.
2. The ophthalmic lens of claim 1 , wherein the diffractive region is located within an angular section of the optic.
3. The ophthalmic lens of claim 1 , wherein the diffractive region is within an angular section that covers between 5 and 66% of the optic.
4. The ophthalmic lens of claim 3 , wherein the stepheights within an angular section of an optic, transition from the stepheight of one adjacent zone to the stepheight of another adjacent zone.
5. The ophthalmic lens of claim 3 , wherein the stepheights Within an angular section of an optic, transition from the stepheight of one diffractive zone to the stepheight of an adjacent monofocal zone.
6. The ophthalmic lens of claim 3 , wherein the stepheights within an angular section of an optic, transition from the stepheight of one diffractive zone to another adjacent refractive zone.
7. An ophthalmic lens, comprising:
an optic having an anterior surface, a posterior surface, and an optical axis, the optic comprising:
at least one refractive region associated with at least one of the anterior surface and the posterior surface; and
at least one diffractive region comprising a plurality of diffractive echelettes, each echelette having a rotational asymmetry with respect to the optical axis, the diffractive region having at least two diffractive orders with associated diffractive optical powers configured for forming, in conjunction with the at least one refractive region, at least a first focus and a second focus.
8. The ophthalmic lens of claim 7 , wherein the refractive region comprises from about 33% to about 66% of the optic.
9. The ophthalmic lens of claim 7 , wherein light at a design wavelength that is incident on the ophthalmic lens is split between the zeroeth diffraction order and the first diffraction order to form the first focus and the second focus.
10. The ophthalmic lens of claim 7 , wherein each echelette comprises a step height that varies rotationally as a function of the rotational angle.
11. The ophthalmic lens of claim 7 , wherein the plurality of diffractive echelettes comprises:
a first section comprising a monofocal diffractive pattern having a first one of the associated diffractive optical powers; and
a second section comprising a plurality of multifocal transitions.
12. The ophthalmic lens of claim 11 , wherein the plurality of multifocal transitions comprise a transition from about 100 percent to the first focus to about 100 percent to the second focus.
13. The ophthalmic lens of claim 11 , wherein the plurality of diffractive echelettes further comprises a third region comprising a variable focus between the first focus and the second focus.
14. The ophthalmic lens of claim 13 , wherein the variable focus comprises about 25 percent to the first focus comprising a near focus, and about 75 percent to the second focus comprising a distant focus.