Ophthalmic lenses having an extended depth of focus for improving intermediate vision
The present disclosure provides an ophthalmic lens (such as an IOL) that is designed to enhance depth of focus for intermediate vision performance, while maintaining distance vision. The lens may include an optic having an anterior surface and a posterior surface disposed about an optical axis. One of the surfaces (e.g., the anterior surface) may have a surface profile involving a superposition of at least three structures or profiles, including a base structure, a phase shift structure having an inner region, an outer region and a transition region, and a zonal structure having an inner power zone and an outer transition zone.
1. An ophthalmic lens, comprising:
an optic having an anterior surface and a posterior surface disposed about an optical axis, at least one of the anterior and posterior surfaces having a composite multi-layered surface profile corresponding to a superposition of at least three profiles comprising a phase shift structure, a zonal structure, and a base structure:
the phase shift structure characterized by an inner region, an outer region, and a transition region, wherein,
the inner region extends radially from the optical axis to a first boundary;
the transition region is disposed between the inner region and the outer region and extends radially from the first boundary to a second boundary, wherein the transition region is adapted such that a phase of radiation incident thereon varies linearly over at least a portion of the radial extent between the first boundary and the second boundary so as to generate a phase shift between the first and second boundaries, the second boundary disposed at a radial distance further from the optical axis than the first boundary; and
the outer region extends radially from the second boundary towards an outermost edge of the optic;
the zonal structure having an inner power zone having a first curvature and an outer transition zone having a second curvature, the inner power zone extending radially from the optical axis to the second boundary, and the outer transition zone extending radially from the optical axis to a third boundary, the third boundary disposed at a radial distance further from the optical axis than the second boundary; and
the base structure having a base curvature extending radially from the optical axis to the outermost edge of the optic.
2. The ophthalmic lens of claim 1 , wherein the composite multi-layered surface profile of the at least one of the anterior and posterior surfaces is described by the following equation:
Z total =Z aux +Z zone1 +Z zone2 +Z base
3. The ophthalmic lens of claim 2 , wherein Z aux corresponds to the phase shift structure and is described by the following equation:
Z
aux
=
{
0
,
(
0
≤
r
<
r
1
)
Δ
_
(
r
-
r
1
)
,
(
r
1
≤
r
<
r
2
)
(
r
2
-
r
1
)
Δ
,
(
r
2
<
r
)
wherein,
r denotes a radial distance from the optical axis of the optic,
r 1 denotes a radial distance from the optical axis to the first boundary;
r 2 denotes a radial distance from the optical axis to the second boundary;
and wherein,
Δ is defined by the following relation:
Δ
=
αλ
(
n
2
-
n
1
)
,
wherein,
n 2 denotes an index of refraction of material forming the optic,
n 2 denotes an index of refraction of a medium surrounding the optic,
λ denotes a design wavelength, and
α denotes a non-integer fraction.
4. The ophthalmic lens of claim 3 , wherein r 1 comprises a value ranging from 0.45 mm to 0.75 mm.
5. The ophthalmic lens of claim 3 , wherein r 2 comprises a value ranging from 0.75 mm to 1.05 mm.
6. The ophthalmic lens of claim 2 , wherein Z zone1 corresponds to the inner power zone and is described by the following equation:
Z
zone
1
=
c
1
r
2
1
+
1
-
(
1
+
k
1
)
c
1
2
r
2
+
A
4
′
r
4
+
A
6
′
r
6
(
0
≤
r
<
r
2
)
wherein,
r denotes a radial distance from the optical axis of the optic,
c 1 denotes the first curvature of the inner power zone,
k 1 denotes a conic constant,
r 2 denotes a radial distance from the optical axis to the second boundary,
A 4 ′ is a fourth order aspheric coefficient, and
A 6 ′ is a sixth order aspheric coefficient.
7. The ophthalmic lens of claim 6 , wherein r 2 comprises a value ranging from 0.45 mm to 0.80 mm.
8. The ophthalmic lens of claim 2 , wherein Z zone2 corresponds to the outer transition zone and is described by the following equation:
Z
zone
2
=
c
2
r
2
1
+
1
-
(
1
+
k
2
)
c
2
2
r
2
+
A
4
″
r
4
+
A
6
″
r
6
(
r
2
≤
r
<
r
3
)
wherein,
r denotes a radial distance from the optical axis of the optic,
c 2 denotes the second curvature of the outer transition zone,
k 2 denotes a conic constant,
r 2 denotes a radial distance from the optical axis to the second boundary,
r 3 denotes a radial distance from the optical axis to the third boundary,
A 4 ″ is a fourth order aspheric coefficient, and
A 6 ″ is a sixth order aspheric coefficient.
9. The ophthalmic lens of claim 8 , wherein r 2 comprises a value ranging from 0.45 mm to 0.80 mm.
10. The ophthalmic lens of claim 8 , wherein r 3 comprises a value ranging from 0.60 mm to 1.20 mm.
11. The ophthalmic lens of claim 2 , wherein Z base corresponds to the base curvature and is described by the following equation:
Z
base
=
c
r
2
1
+
1
-
(
1
+
k
)
c
2
r
2
+
A
4
r
4
+
A
6
r
6
where
r
≥
r
3
wherein,
r denotes a radial distance from the optical axis of the optic,
c denotes a value of the base curvature,
k denotes a conic constant,
r 3 denotes a radial distance from the optical axis to the third boundary,
A 4 is a fourth order aspheric coefficient, and
A 6 is a sixth order aspheric coefficient.
12. The ophthalmic lens of claim 11 , wherein r 3 comprises a value ranging from 0.60 mm to 1.20 mm.
13. The ophthalmic lens of claim 1 , wherein:
a first region of the optic comprises a first composite aspheric profile, the first region defined from the optical axis and extending radially to the first boundary;
a second region of the optic comprises a second composite aspheric profile, the second region defined from the first boundary and extending radially to the second boundary;
a third region of the optic comprises a third composite aspheric profile, the third region defined from the second boundary and extending radially to the third boundary; and
a fourth region of the optic comprises a fourth composite aspheric profile, the fourth region defined from the third boundary to the outermost edge of the optic.
14. The ophthalmic lens of claim 1 , wherein the inner power zone is disposed to enhance depth of focus for intermediate vision performance.
15. The ophthalmic lens of claim 14 , wherein the phase shift structure is disposed to mitigate pupil-dependent focal shift effect caused by the enhanced depth of focus by the inner power zone.
16. An ophthalmic lens, comprising:
an optic having an anterior surface and a posterior surface disposed about an optical axis, at least one of the anterior and posterior surfaces having a composite multi-layered surface profile corresponding to a superposition of at least three profiles comprising a phase shift structure, a zonal structure, and a base structure:
the phase shift structure characterized by an inner region, an outer region, and a transition region, wherein,
the inner region extends radially from the optical axis to a first boundary;
the transition region is disposed between the inner region and the outer region and extends radially from the first boundary to a second boundary, the second boundary disposed at a radial distance further from the optical axis than the first boundary, wherein the transition region is adapted such that a phase of radiation incident thereon varies linearly over at least a portion of the radial extent between the first boundary and the second boundary so as to generate a phase shift between the first and second boundaries; and
the outer region extends radially from the second boundary towards the outermost edge of the optic
the zonal structure having an inner power zone having a first curvature and an outer transition zone having a second curvature, wherein the inner power zone extends radially from the optical axis to the second boundary and the outer transition zone extends radially to a third boundary, the third boundary disposed at a radial distance further from the optical axis than the second boundary; and
the base structure having a base curvature extending radially from the third boundary to an outermost edge of the optic.
17. The ophthalmic lens of claim 16 , wherein the composite multi-layered surface profile of the at least one of the anterior and posterior surfaces is described by the following equation:
Z total =Z aux +Z zone1 +Z zone2 +Z base
18. The ophthalmic lens of claim 17 , wherein Z aux corresponds to the phase shift structure and is described by the following equation:
Z
aux
=
{
0
,
(
0
≤
r
<
r
1
)
Δ
_
(
r
-
r
1
)
,
(
r
1
≤
r
<
r
2
)
(
r
2
-
r
1
)
Δ
,
(
r
2
<
r
)
wherein,
r denotes a radial distance from the optical axis of the optic,
r 1 denotes a radial distance from the optical axis to the first boundary;
r 2 denotes a radial distance from the optical axis to the second boundary;
and wherein,
Δ is defined by the following relation:
Δ
=
αλ
(
n
2
-
n
1
)
,
wherein,
n 1 denotes an index of refraction of material forming the optic,
n 2 denotes an index of refraction of a medium surrounding the optic,
λ denotes a design wavelength, and
α denotes a non-integer fraction.
19. The ophthalmic lens of claim 18 , wherein r 1 comprises a value ranging from 0.45 mm to 0.75 mm.
20. The ophthalmic lens of claim 18 , wherein r 2 comprises a value ranging from 0.75 mm to 1.05 mm.
21. The ophthalmic lens of claim 17 , wherein Z zone1 corresponds to the inner power zone and is described by the following equation:
Z
zone
1
=
c
1
r
2
1
+
1
-
(
1
+
k
1
)
c
1
2
r
2
+
A
4
′
r
4
+
A
6
′
r
6
(
0
≤
r
<
r
2
)
wherein,
r denotes a radial distance from the optical axis of the optic,
c 1 denotes the first curvature of the inner power zone,
k 1 denotes a conic constant,
r 2 denotes a radial distance from the optical axis to the second boundary,
A 4 ′ is a fourth order aspheric coefficient, and
A 6 ′ is a sixth order aspheric coefficient.
22. The ophthalmic lens of claim 21 , wherein r 2 comprises a value ranging from 0.45 mm to 0.80 mm.
23. The ophthalmic lens of claim 17 , wherein Z zone2 corresponds to the outer transition zone and is described by the following equation:
Z
zone
2
=
c
2
r
2
1
+
1
-
(
1
+
k
2
)
c
2
2
r
2
+
A
4
″
r
4
+
A
6
″
r
6
(
r
2
≤
r
<
r
3
)
wherein,
r denotes a radial distance from the optical axis of the optic,
c 2 denotes the second curvature of the outer transition zone,
k 2 denotes a conic constant,
r 2 denotes a radial distance from the optical axis to the second boundary,
r 3 denotes a radial distance from the optical axis to the third boundary,
A 4 ″ is a fourth order aspheric coefficient, and
A 6 ″ is a sixth order aspheric coefficient.
24. The ophthalmic lens of claim 23 , wherein r 2 comprises a value ranging from 0.45 mm to 0.80 mm.
25. The ophthalmic lens of claim 23 , wherein r 3 comprises a value ranging from 0.60 mm to 1.20 mm.
26. The ophthalmic lens of claim 17 , wherein Z base corresponds to the base curvature and is described by the following equation:
Z
base
=
c
r
2
1
+
1
-
(
1
+
k
)
c
2
r
2
+
A
4
r
4
+
A
6
r
6
where
r
≥
r
3
wherein,
r denotes a radial distance from the optical axis of the optic,
c denotes a value of the base curvature,
k denotes a conic constant,
r 3 denotes a radial distance from the optical axis to the third boundary,
A 4 is a fourth order aspheric coefficient, and
A 6 is a sixth order aspheric coefficient.
27. The ophthalmic lens of claim 26 , wherein r 3 comprises a value ranging from 0.60 mm to 1.20 mm.
28. The ophthalmic lens of claim 16 , wherein:
a first region of the optic comprises a first composite aspheric profile, the first region defined from the optical axis and extending radially to the first boundary;
a second region of the optic comprises a second composite aspheric profile, the second region defined from the first boundary and extending radially to the second boundary;
a third region of the optic comprises a third composite aspheric profile, the third region defined from the second boundary and extending radially to the third boundary; and
a fourth region of the optic comprises a fourth composite aspheric profile, the fourth region defined from the third boundary to the outermost edge of the optic.
29. The ophthalmic lens of claim 16 , wherein the inner power zone is disposed to enhance depth of focus for intermediate vision performance.
30. The ophthalmic lens of claim 29 , wherein the phase shift structure is disposed to mitigate pupil-dependent focal shift effect caused by the enhanced depth of focus by the inner power zone.