Lenses, devices and methods for ocular refractive error
Certain embodiments are directed to lenses, devices and/or methods. For example, a lens for an eye having an optical axis and an aberration profile along its optical axis, the aberration profile having a focal distance and including higher order aberrations having at least one of a primary spherical aberration component C(4,0) and a secondary spherical aberration component C(6,0). The aberration profile may provide, for a model eye with no aberrations and an on-axis length equal to the focal distance: (i) a peak, first retinal image quality (RIQ) within a through focus range that remains at or above a second RIQ over the through focus range that includes said focal distance, where the first RIQ is at least 0.35, the second RIQ is at least 0.1 and the through focus range is at least 1.8 Diopters; (ii) a RIQ of 0.3 with a through focus slope that improves in a direction of eye growth; and (iii) a RIQ of 0.3 with a through focus slope that degrades in a direction of eye growth. The RIQ may be Visual Strehl Ratio or similar measured along the optical axis for at least one pupil diameter in the range 3 mm to 6 mm, over a spatial frequency range of 0 to 30 cycles/degree inclusive and at a wavelength selected from within the range 540 nm to 590 nm inclusive.
1. A lens for an eye, the lens having an optical axis and an aberration profile about its optical axis, the aberration profile:
having a focal distance; and
including higher order aberrations having at least one of a primary spherical aberration component (C(4,0)) and a secondary spherical aberration component (C(6,0)),
wherein the aberration profile provides, for a model eye with no aberrations and an on-axis length equal to the focal distance:
a retinal image quality (RIQ) with a through focus slope that degrades in a direction of eye growth; and
a RIQ of at least 0.30;
wherein said RIQ is Visual Strehl Ratio measured along the optical axis for at least one pupil diameter in the range 3 mm to 6 mm, over a spatial frequency range of 0 to 30 cycles/degree inclusive and at a wavelength selected from within the range 540 nm to 590 nm inclusive.
2. The lens of claim 1 , wherein the higher order aberrations include at least two spherical aberration terms selected from the group C(4,0) to C(20,0).
3. The lens of claim 1 , wherein the average slope over a horizontal field of at least −20° to +20° degrades in a direction of eye growth.
4. The lens of claim 1 , wherein the aberration profile provides a RIQ of at least 0.30 at the focal length for all pupil diameters in the range 3 mm to 6 mm.
5. The lens of claim 1 , wherein the aberration profile provides a RIQ with a through focus slope that degrades in a direction of eye growth when primary astigmatism is added to the aberration profile.
6. The lens of claim 1 , wherein the aberration profile provides a RIQ with a through focus slope that degrades in a direction of eye growth when secondary astigmatism is added to the aberration profile.
7. The lens of claim 1 , wherein said RIQ is
RIQ
=
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min
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max
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wherein:
Fmin is 0 cycles/degree and Fmax is 30 cycles/degree;
CSF(x, y) denotes the contrast sensitivity function CSF(F)=2.6(0.0192+0.114f)e −(0.114f)^1.1 , where f specifies the tested spatial frequency, in the range of F min to F max ;
FT denotes a 2D fast Fourier transform;
A(ρ,θ) denotes the pupil diameter;
W(ρ,θ) denotes wavefront phase of the test case W(ρ, θ)=Σ i=1 k α i Z i (ρ, θ) measured for i=1 to 20;
Wdiff(ρ, θ) denotes wavefront phase of the diffraction limited case;
ρ and θ are normalised polar coordinates, where ρ represents the radial coordinate and
θ represents the angular coordinate or azimuth; and
λ denotes wavelength.
8. A lens including an optical axis and an aberration profile about the optical axis that provides:
a focal distance for a C(2,0) Zernike coefficient term;
a peak Visual Strehl Ratio (‘first Visual Strehl Ratio’) within a through focus range, and
a Visual Strehl Ratio that remains at or above a second Visual Strehl Ratio over the through focus range that includes said focal distance,
wherein the Visual Strehl Ratio is measured for a model eye with no aberration and is measured along the optical axis for at least one pupil diameter in the range 3 mm to 5 mm, over a spatial frequency range of 0 to 30 cycles/degree inclusive, at a wavelength selected from within the range 540 nm to 590 nm inclusive,
and wherein the first Visual Strehl Ratio is at least 0.35, the second Visual Strehl Ratio is at least 0.10 and the through focus range is at least 1.8 Diopters.
9. The lens of claim 8 , wherein the first Visual Strehl Ratio is at least 0.4, 0.5, 0.6, 0.7 or 0.8.
10. The lens of claim 8 , wherein the through focus range is at least 1.9, 2.0, 2.1, 2.25 or 2.5 Diopters.
11. The lens of claim 8 , wherein the lens has a prescription focal distance located within 0.75 Diopters (inclusive) of an end of the through focus range.
12. The lens of claim 8 , wherein the end of the through focus range is the negative power end.
13. The lens of claim 8 , wherein the end of the through focus range is the positive power end.
14. The lens of claim 8 , wherein the Visual Strehl Ratio remains at or above the second Visual Strehl Ratio over the through focus range and over a range of pupil diameters of at least 2 mm.
15. The lens of claim 8 , wherein the higher order aberrations include at least two spherical aberration terms selected from the group C(4,0) to C(20,0).
16. The lens of claim 8 , wherein the higher order aberrations include at least three spherical aberration terms selected from the group C(4,0) to C(20,0).
17. A method for a presbyopic eye, the method comprising forming an aberration for the eye and applying or prescribing the aberration profile, the aberration profile:
having a focal distance; and
including at least one of a primary spherical aberration component (C(4,0)) and a secondary spherical aberration component (C(6,0)),
wherein the aberration profile provides, for the eye:
a retinal image quality (RIQ) with a through focus slope that degrades in a direction of eye growth; and
a RIQ of at least 0.30;
wherein said RIQ is Visual Strehl Ratio measured along the optical axis for at least one pupil diameter in the range 3 mm to 6 mm, over a spatial frequency range of 0 to 30 cycles/degree inclusive and at a wavelength selected from within the range 540 nm to 590 nm inclusive.
18. The method of claim 17 , wherein applying or prescribing the aberration profile comprises providing a lens, the lens having an aberration profile including at least two spherical aberration terms selected from the group C(4,0) to C(20,0).
19. The method of claim 17 , wherein the method further comprising identifying a wavefront aberration profile for the hyperopic eye and applying or prescribing the aberration profile, the wavefront aberration profile including at least one spherical aberration term, wherein the prescription focal distance of the lens is determined taking into account said spherical aberration and wherein at the prescription focal distance the wavefront aberration profile provides an improving retinal image quality in the direction posterior to the retina.
20. The method of claim 17 , the method further comprising identifying a wavefront aberration profile for the presbyopic eye, the wavefront aberration profile including at least one spherical aberration term, wherein the prescription focal distance of the lens is determined taking into account said spherical aberration and wherein the prescription focal distance of the lens is at least +0.25 D relative to a focal distance for a C(2,0) Zernike coefficient term of the wavefront aberration and producing a device, lens or corneal profile for the eye to affect said wavefront aberration profile.