Single focus enhanced ophthalmic lens with pre-microwave perturbation

Abstract

Disclosed is a monofocal ophthalmic lens whose performance is enhanced for presbyopia correction, whose wavefront is modified with perturbations at its central paraxial region. Disturbance may be achieved by surface relief of its front or rear surface or by refractive index modification of the lens material. The perturbation takes the form of an even function with respect to the radius of the wavefront aperture, such as, but not limited to, cosine, Fourier harmonic, Zernike polynomial, or Taylor series.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 385,800, filed on December 2, 2022. The entire disclosure of that prior application is considered part of the disclosure of the attached application and is incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to ophthalmic lenses, and more particularly to monofocal ophthalmic lenses having wavefront perturbations over a central paraxial region thereof. Background Art

[0004] In the elderly, a common form of eye disease is cataract. Cataract is a cloudy area in the lens of the eye, which causes decreased vision. Cataracts usually develop slowly and can affect one or both eyes, often causing difficulty in daily tasks, such as driving, reading or recognizing faces. If not treated, cataracts may cause blindness. A common form of treatment is to remove the natural lens, which is called the crystalline body, and replace it with an artificial lens, which is called an artificial lens (IOL). IOL can be designed to be a single focus or to provide excellent vision for several focuses. The former is called a monofocal IOL and usually uses an aspheric surface. In contrast, the latter is called a multifocal IOL and uses a diffractive surface.

[0005] Multifocal IOLs with more than one focus are often preferred over monofocal IOLs because such lenses generally eliminate the need for glasses. However, multifocal lenses are more expensive than monofocal lenses due to their diffractive design, and patients using multifocal lenses are many times less satisfied with their visual experience than patients using monofocal lenses. Therefore, many IOL monofocal designs attempt to improve the depth of focus at the single focus of the lens by modifying its aspheric surface.

[0006] One example is U.S. Publication No. 20200121448, entitled “Extended depth of focus intraocular lens” by Myoung-Taek Choi et al., which discloses an IOL including an optic zone and a modulating surface profile formed in the optic zone and configured to focus incident light at multiple focal points, wherein the modulating surface profile is combined with a base surface profile of the optic zone. The modulating surface can have a profile that is sinusoidal, triangular, or some form thereof, the purpose of which is to extend the depth of focus. Another example is U.S. Patent No. 11083566, entitled “Ophthalmic lens having an extended depth of focus” by Xin Hong et al. Here, Hong discloses an ophthalmic lens that includes an optical component having a front surface, a back surface, and an optical axis. At least one of the front surface and the back surface includes a first zone extending from the optical axis to a first radial boundary and a second zone extending from the first radial boundary to an edge of the optical component. The first zone includes an inner region and an outer region separated by a phase shift feature, and the phase shift includes ridges extending outward from the inner region and the outer region. The optical combination of the second zone and the inner region of the first zone, the phase shifting feature and the outer region extends the depth of focus of the lens.

[0007] While the above approaches to increasing the depth of focus of monofocal lenses are acceptable, the art is open to other approaches that may help extend the depth of focus while also simplifying the manufacture of the lenses, thereby reducing the cost of wearing such lenses. Summary of the invention

[0008] Disclosed herein is an ophthalmic lens, such as a spectacles, contact lens, or artificial lens, having a substantially monofocal optic, but having a zone around a central paraxial region in which a wavefront perturbation has been added. The wavefront perturbation can be achieved by surface relieving the front or back surface of the lens or by modifying the refractive index of the lens material at a depth inside the optic. The purpose of the wavefront perturbation is to extend the depth of focus, which can correct the wearer's presbyopia under photopic conditions at all distances. Under intermediate vision, the lens becomes monofocal.

[0009] For some background, FIG2 shows a monofocal ophthalmic lens 10 from which the wavefront emerging is primarily spherical converging to a single focus, shown as 14 in FIG2 . The through-focus modulation transfer function (MTF) of the lens 10 is shown as 16. Light converging at the focus 14 is said to be emmetropic vision. It is desirable for a presbyopic or pseudophakic patient wearing the lens 10 to have a wider monofocal through-focus MTF 16, thereby indicating a greater depth of focus extending from the emmetropic focus toward the myopic direction.

[0010] Figure 3 A monofocal enhancement ophthalmic lens 20 of the present disclosure is shown with a central paraxial zone 26. The paraxial zone 26 contains a wavefront perturbation that diffracts the wavefront emerging from the lens 20 and splits it into a number of sub-wavefronts, thereby allowing the incident light energy to be distributed from the focal point 14 to the depth of focus in the myopic direction. As a result, the width of the through-focus MTF 16 is increased, and thus its depth of focus is increased. Such a wavefront perturbed ophthalmic lens can allow presbyopic or pseudophakic wearers to obtain pseudo-accommodative function and see clearly within the depth of focus of the lens under photopic conditions.

[0011] Disclosed herein is a monofocal ophthalmic lens 20 having a perturbation within a paraxial zone 22. The perturbation is a continuous even function of the radius of the paraxial zone 22 and is rotationally symmetric about the optical axis of the lens 20.

[0012] Other features and advantages of the various embodiments of the present invention will be apparent to those skilled in the art from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be more fully understood from the detailed description and accompanying drawings. Other systems, methods, features and advantages of the present invention will be or will become apparent to those skilled in the art upon examination of the following drawings and detailed description. All of these additional systems, methods, features and advantages are intended to be included within this description, within the scope of the present invention, and protected by the appended claims. The components shown in the drawings are not necessarily drawn to scale and may be enlarged to better illustrate important features of the present invention. The dimensions disclosed or shown are exemplary only. In the drawings, the same reference numerals may indicate the same components in different views, wherein:

[0014] Figure 1 A monofocal enhancement ophthalmic lens of the present disclosure having a central paraxial zone containing microwave front disturbances is shown;

[0015] FIG. 2 illustrates how a prior art monofocal ophthalmic lens works;

[0016] Figure 3 shows how the monofocal enhancement ophthalmic lens of the present disclosure works;

[0017] Figure 4 shows a surface profile of a first embodiment in which the perturbation is represented as a cosine series;

[0018] Figure 5 The through-focus MTF of the first embodiment is shown in which the disturbance is expressed as a cosine series.

[0019] Figure 6 shows a surface profile of a second embodiment in which the perturbation is represented as a cosine series;

[0020] Figure 7 The through-focus MTF of the second embodiment is shown in which the disturbance is expressed as a cosine series.

[0021] Figure 8 shows a surface profile of a third embodiment in which the perturbation is represented as a Fourier harmonic series;

[0022] Fig. 9 The through-focus MTF of a third embodiment is shown in which the perturbation is represented as a Fourier harmonic series.

[0023] Fig.10 shows a surface profile of a fourth embodiment in which the perturbation is represented as a Fourier harmonic series;

[0024] Fig.11 The through-focus MTF of a fourth embodiment is shown in which the perturbation is represented as a Fourier harmonic series.

[0025] Fig.12 shows a surface profile of a fifth embodiment in which the perturbation is represented as a Fourier harmonic series;

[0026] Fig.13 The through-focus MTF of the fifth embodiment is shown in which the disturbance is expressed as a Fourier harmonic series. DETAILED DESCRIPTION

[0027] Exemplary embodiments relate to ophthalmic devices such as spectacles, IOLs, and contact lenses. The following description is presented to enable one of ordinary skill in the art to make and use the invention, and is provided in the context of a patent application and its requirements. Modifications to the exemplary embodiments and general principles and features described herein will be apparent. Exemplary embodiments are described primarily in terms of specific methods and systems provided in specific embodiments. However, the methods and systems will operate effectively in other embodiments. For example, the methods and systems are described primarily in terms of IOLs. However, the methods and systems can be used with contact lenses and spectacles.

[0028] Disclosed herein are monofocal enhancement ophthalmic lenses such as spectacles, contact lenses, or IOLs. Figure 1 A lens 20 is shown as an IOL, i.e., a monofocal enhancement lens of the present disclosure, which includes an optical component 22 and a haptic 24, and further includes a paraxial region 26 around the optical axis and a monofocal region 28 extending from the paraxial region 26 to the edge of the optical component 22. The radius R0 of the paraxial region 26 is Figure 1, which is shown as a dotted line. In the paraxial region 26, a wavefront perturbation has been added. The wavefront perturbation can be achieved by surface relief on the front and back surfaces of the optical component 22 or by modifying the refractive index of the material within the optical component 22. The purpose of the wavefront perturbation is to extend the depth of focus, which can correct the wearer's presbyopia under clear vision conditions at all distances from far to near. The wavefront perturbation at the front and back surfaces of the optical component or the wavefront perturbation modified by the refractive index of the lens material at a certain depth inside the optical component is a continuous even function of the aperture radius of the wavefront. Therefore, it is also rotationally symmetric around the optical axis and continuously differentiable within the paraxial region 26. The wavefront W(r) of the monofocal enhanced lens consists of two parts, one is the basic monofocal wavefront W a (r); the other is W p (r), i.e., the disturbance wave front. This is expressed in equation (1).

[0029] W(r)=W a (r)+W a (r) Formula (1)

[0030] Basic monofocal wavefront W a (r) is typically a standard aspheric wavefront, as shown in equation (2).

[0031]

[0032] The disturbed portion of the wavefront is confined to a paraxial region 26 having a radius R0. Beyond the paraxial region 26, from R0 to the edge of the lens aperture of radius R, the probation is a constant C, as shown in equation (3).

[0033] In addition, the first-order derivative of the disturbance wave front is also:

[0034]

[0035] in:

[0036] R is the radius of the lens aperture;

[0037] R0 is the radius of the perturbed aperture, such as Figure 1 As shown in;

[0038] r is the distance from the optical axis; and

[0039] f(r) is a continuous even function of r.

[0040] In the engineering design of wavefront perturbations for desired performance, f(r) must be parameterized. Below are at least three ways to parameterize f(r).

[0041] f(r) can be parameterized using a cosine series, as shown in equation (4) below:

[0042]

[0043] in:

[0044] ω=2π / D Formula (5)

[0045] r is the distance from the optical axis; and

[0046] D is the diameter of the paraxial region 26, or 2R0 for short.

[0047] In the design of wavefront perturbations, the order N of the cosine series together with a n (where (n=0, 1, 2, ..., N)) will be optimized for the wavefront perturbation to achieve the desired performance of the lens 20. The optimal wavefront perturbation expressed as a cosine series will have N in the range of 3≤N≤10, R0 in the range of 0.5mm≤R0≤2mm, and R0 in the range of -0.5≤a n a in the range of ≤0.5 n The following paragraphs disclose two embodiments of wavefront perturbations expressed as cosine series.

[0048] A first embodiment of a wavefront perturbation expressed as a cosine series has the parameters shown in Table 1.

[0049] Table 1: Parameters of a second embodiment of the wavefront perturbation expressed as a cosine series. R0 is measured in millimeters and the coefficients of the cosine series are measured in waves.

[0050]

[0051] Figure 4 1 shows the wavefront disturbance sag height obtained on the surface of the optical component 22 of the first embodiment, where the x-axis is the surface of the optical component 22 and the y-axis is the height of the sag. The optical axis of the optical component 22 is at 0.0 mm on the x-axis. The wavefront sag of the disturbance is the horizontal outer portion of R0, where R0 is the radius of the paraxial region 26, as shown in FIG. Figure 1 As shown. Figure 5 , the through-focus MTF is shown for the perturbed wavefront of the first embodiment at a 3 mm aperture, or pupil size of the eye. The solid line shows the through-focus MTF at 25 cycles / mm (CPMM), while the dashed line shows the through-focus MTF at 50 CPMM. Figure 5 Comparing the through-focus MTF of 16 with the single focus through-focus MTF in FIG. 2 , it can be seen that the wavefront perturbation of the first embodiment has an extended depth of focus compared to the prior art single focus lens shown in FIG. 2 .

[0052] A second embodiment of the wavefront perturbation, also expressed as a cosine series, has the parameters shown in Table 2.

[0053] Table 2: Parameters of a second embodiment of the wavefront perturbation expressed as a cosine series. R0 is measured in millimeters and the coefficients of the cosine series are measured in waves.

[0054]

[0055] Figure 6 1 shows the wavefront disturbance sag obtained on the surface of the optical component 22 of the second embodiment, where the x-axis is the surface of the optical component 22 and the y-axis is the height of the sag. The optical axis of the optical component 22 is at 0.0 mm on the x-axis. The wavefront sag of the disturbance is the horizontal outer portion of R0, where R0 is the radius of the paraxial region 26, as shown in FIG. Figure 1 As shown. Figure 7 In FIG. 1 , the through-focus MTF is shown for the perturbed wavefront of the second embodiment at a 3 mm aperture. The solid line shows the through-focus MTF at 25 cycles / mm (CPMM), while the dashed line shows the through-focus MTF at 50 CPMM. Figure 7 Comparing the through-focus MTF of 16 with the single focus through-focus MTF in FIG. 2 , it can be seen that the wavefront perturbation of the second embodiment has an extended depth of focus compared to the prior art single focus lens shown in FIG. 2 .

[0056] The wavefront disturbance function f(r) can also be expressed as a Fourier harmonic series, as shown in equation (6).

[0057]

[0058] Equivalently, equation (6) can be expressed in the form of equation (7):

[0059]

[0060] in,

[0061] ω=πP / λ Formula (8)

[0062] M is an integer representing the order of the first polynomial.

[0063] N is an integer representing the order of the Fourier harmonic series;

[0064] λ is the wavelength of the incident light; and

[0065] r is the distance from the optical axis.

[0066] In the engineering design of wavefront disturbance, M, α i (i=1,2,...M) and N together with P, A n ,φ n(n=0, 1, 2, . . . , N) will be determined for the wavefront perturbation f(r) to achieve the desired lens performance.

[0067] Just like the cosine wavefront perturbation, there is a range of values ​​for each design parameter of the Fourier series wavefront perturbation. Typically, R0 is in the range of 0.5 mm ≤ R0 ≤ 2.5 mm; M is in the range of 1 ≤ M ≤ 3, N is in the range of 5 ≤ N ≤ 15, and A is in the range of 1 ≤ M ≤ 3. n At -0.5≤A n ≤0.5, and φ n In -π≤φ n ≤π. Although higher orders of M and N can be used, the values ​​of the corresponding coefficients are minimal.

[0068] A third embodiment of the wavefront perturbation expressed as a Fourier harmonic series has the following parameters: P = 0.56 (m -1 ), R0 = 1.083 (mm), and Table 3 contains Fourier harmonic parameters. The aspheric parameter in this embodiment is α1 = -1.02564.

[0069] Table 3: Fourier harmonic parameters for the third embodiment of the wavefront perturbation.

[0070]

[0071] Figure 8 1 shows the wavefront disturbance sagitta obtained on the surface of the optical component 22 of the third embodiment, where the x-axis is the surface of the optical component 22 and the y-axis is the height of the sagitta. The optical axis of the optical component 22 is at 0.0 mm on the x-axis. The wavefront sagitta of the disturbance is the horizontal outer part of R0, where R0 is the radius of the paraxial region 26, as shown in FIG. Figure 1 As shown. Fig. 9 , the through-focus MTF is shown for the perturbed wavefront of the third embodiment at 3 mm aperture. The solid line shows the through-focus MTF at 25 cycles / mm (CPMM), while the dashed line shows the through-focus MTF at 50 CPMM. Fig. 9 By comparing the through-focus MTF of 16 with the single focus through-focus MTF in FIG. 2 , it can be seen that the wavefront perturbation of the third embodiment has an extended depth of focus compared to the prior art single focus lens shown in FIG. 2 .

[0072] A fourth embodiment of the wavefront perturbation expressed as a Fourier harmonic series has the following parameters: P = 0.5 (m -1 ), λ=0.546 (μm), R0=1.32 (mm), and Table 4 contains Fourier harmonic parameters. The aspheric parameter in this embodiment is α1=-1.37363.

[0073] Table 4: Fourier harmonic parameters for the fourth embodiment of the wavefront perturbation.

[0074]

[0075] Fig.10 1 shows the wavefront disturbance sagitta obtained on the surface of the optical component 22 of the fourth embodiment, where the x-axis is the surface of the optical component 22 and the y-axis is the height of the sagitta. The optical axis of the optical component 22 is at 0.0 mm on the x-axis. The wavefront sagitta of the disturbance is the horizontal outer part of R0, where R0 is the radius of the paraxial region 26, as shown in FIG. Figure 1 As shown. Fig.11 , the through-focus MTF is shown for the perturbed wavefront of the fourth embodiment at a 3 mm aperture. The solid line shows the through-focus MTF at 25 cycles / mm (CPMM), while the dashed line shows the through-focus MTF at 50 CPMM. Fig.11 By comparing the through-focus MTF of 16 with the single-focus through-focus MTF in FIG. 2 , it can be seen that the wavefront perturbation of the fourth embodiment has an extended depth of focus compared with the prior art single-focus lens shown in FIG. 2 .

[0076] A fifth embodiment of the wavefront perturbation expressed as a Fourier harmonic series has the following parameters: P = 0.5 (m -1 ), λ=0.546 (μm), R0=1.45 (mm), and Table 5 contains Fourier harmonic parameters. The aspheric parameter in this embodiment is α1=-1.37363.

[0077] Table 5: Fourier harmonic parameters for the fifth embodiment of the wavefront perturbation.

[0078]

[0079] Fig.12 1 shows the wavefront disturbance sagitta obtained on the surface of the optical component 22 of the fifth embodiment, where the x-axis is the surface of the optical component 22 and the y-axis is the height of the sagitta. The optical axis of the optical component 22 is at 0.0 mm on the x-axis. The wavefront sagitta of the disturbance is the horizontal outer part of R0, where R0 is the radius of the paraxial region 26, as shown in FIG. Figure 1 As shown. Fig.13 , the through-focus MTF is shown for the perturbed wavefront of the fifth embodiment at 3 mm aperture. The solid line shows the through-focus MTF at 25 cycles / mm (CPMM), while the dashed line shows the through-focus MTF at 50 CPMM. Fig.13 By comparing the through-focus MTF of 16 with the single-focus through-focus MTF in FIG. 2 , it can be seen that the wavefront perturbation of the fifth embodiment has an extended depth of focus compared with the prior art single-focus lens shown in FIG. 2 .

[0080] The wavefront perturbation function f(r) can also be expressed as an even Taylor series, as shown in equation (9), which is infinitely differentiable at the center of the lens aperture where r=0.

[0081]

[0082] in:

[0083] pn are the coefficients of the Taylor series; and

[0084] r is the distance from the optical axis of the optical component.

[0085] In the engineering design of wavefront disturbances, the order N of the Taylor series together with p n (n=0, 1, 2, ..., N) will be optimized for wavefront perturbations to achieve the desired performance of the ophthalmic lens.

[0086] The wavefront disturbance function f(r) can also be expressed as a Zernike polynomial, as shown in equation (10).

[0087]

[0088] in:

[0089] r and θ are the radial and azimuthal polar coordinates on the lens aperture;

[0090] r is the radius of the lens aperture;

[0091] n and m are integer variables indicating the radial and azimuthal orders of the polynomial;

[0092] are the corresponding coefficients; and

[0093] are the so-called Zernike polynomials.

[0094] Since f(r) is rotationally symmetric, the coefficients of the non-zero azimuthal order in equation (10) must all be zero. In other words, the Zernike polynomials should consist of only m=0 terms.

[0095]

[0096]

[0097] Since f(r) is rotationally symmetric, the coefficients of the non-zero azimuthal orders in equation (11) must all be zero. In other words, the Zernike polynomials should consist only of m=0 terms. Then, the desired Zernike polynomial form of the wavefront perturbation can be expressed as equation (13).

[0098]

[0099] Below are explicit expressions for the first 20 terms of the rotationally symmetric Zernike polynomials.

[0100]

[0101] Higher-order Zernike polynomial forms can be generated using equation (12), and the industry has provided optical design software such as Zemax software.

[0102] In the engineering design of wavefront disturbances, the order N of the Zernike polynomials together with z n (n=0, 1, 2, ..., N) will be optimized for wavefront perturbations to achieve the desired performance of the ophthalmic lens.

[0103] The rotated Zernike polynomial wavefront perturbation in equation (13) is actually the same as the Taylor series in equation (9). However, the wavefront perturbation expressed in equation (13) can make the engineering design converge to the optimal wavefront perturbation faster to obtain the desired IOL performance.

[0104] Based on the mathematical principle of Taylor series, cosine series and Fourier harmonic series types of wavefront disturbances can also be expressed in the form of Taylor series, and therefore can also be expressed in the form of Zernike polynomials. However, the order of the equivalent Taylor series will be much higher than the order of the cosine and Fourier harmonic series.

[0105] Exemplary embodiments of the present invention have been disclosed in an exemplary manner. Therefore, the terms used throughout the text should be interpreted in a non-restrictive manner. Although those skilled in the art may make minor modifications to the teachings herein, it should be understood that all such embodiments are intended to be limited to the scope of the patents guaranteed herein, so such embodiments reasonably fall within the scope of the progress contributed thereby, and the scope should not be limited unless considering the attached claims and their equivalents.

Claims

1. An ophthalmic lens comprising: An optical component, comprising: front surface, rear surface, At the edge of its periphery, and the optical axis, Wherein, at least one of the front surface and the rear surface comprises: a first region extending from the optical axis to a radial boundary, the first region having an aspherical wavefront and a perturbed wavefront, the perturbed wavefront being represented as a continuous even function, and A second zone extends from the radial boundary to the edge, the second zone having an aspherical wavefront.

2. The ophthalmic lens according to claim 1, wherein: The disturbance wavefront is rotationally symmetric about the optical axis.

3. The ophthalmic lens according to claim 1, wherein: The disturbed wavefront is achieved by surface embossing the front surface and the back surface of the optical component.

4. The ophthalmic lens according to claim 1, wherein: The perturbed wavefront is achieved by utilizing refractive index modification of materials within the optical component.

5. The ophthalmic lens according to claim 1, wherein: The continuous even function of the disturbance wavefront is expressed as a cosine series of the following form: Where: ω=2π / D r is the distance from the optical axis; and D is the diameter of the first zone.

6. The ophthalmic lens according to claim 5, wherein: The cosine series has N in the range of 3≤N≤10, R0 in the range of 0.5mm≤R0≤2mm, and R1 in the range of -0.5≤a n a in the range of ≤0.5 n .

7. The ophthalmic lens according to claim 1, wherein: The continuous even function of the disturbance wavefront is expressed as a Fourier harmonic series in the following form: Where: ω=πP / λ M is an integer representing the order of the first polynomial; N is an integer representing the order of the Fourier harmonic series; λ is the wavelength of the incident light; and r is the distance from the optical axis.

8. The ophthalmic lens according to claim 7, wherein: The Fourier harmonic series has R0 in the range of 0.5 mm ≤ R0 ≤ 2.5 mm, M in the range of 1 ≤ M ≤ 3, N in the range of 5 ≤ N ≤ 15, and N in the range of -0.5 ≤ A n A in the range of ≤0.5 n and in -π≤φ n φ in the range of ≤π n .

9. The ophthalmic lens according to claim 1, wherein: The continuous even function of the disturbance wave front is expressed as an even Taylor series of the following form: in: P n are the coefficients of the Taylor series; and r is the distance from the optical axis of the optical component.

10. The ophthalmic lens according to claim 1, wherein: The continuous even function of the disturbance wavefront is expressed as an even Zernike polynomial of the following form: in: r and θ are the radial and azimuthal polar coordinates on the lens aperture; r is the radius of the lens aperture; n and m are integer variables indicating the radial and azimuthal orders of the polynomial; are the corresponding coefficients; and are the so-called Zernike polynomials.

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