Multifocal intraocular lens

Abstract

A multifocal IOL comprising at least one diffractive surface comprising a plurality of discrete, adjacent, diffractive concentric rings having a radial phase profile cross-section with an approximately symmetrical diffractive surface topography, an odd number of diffraction orders greater than 3, and an asymmetric distribution of energy flux in the diffraction orders.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 730,769, filed on September 13, 2018, entitled “MULTIFOCALINTRAOCULAR LENS,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] In some embodiments of the invention, the invention relates generally to multifocal intraocular lenses, and more particularly, but not exclusively, to multifocal, diffractive, intraocular ophthalmic lenses. Background Art

[0004] An intraocular lens (IOL) is a lens implanted inside the eye as part of the treatment of cataracts or myopia. Available multifocal IOLs are generally able to restore visual function and allow eyeglasses independence after their implantation, with high rates of patient satisfaction.

[0005] Multifocal IOLs can correct farsightedness, nearsightedness and all intermediate distances. Multifocal IOLs improve near vision by splitting the light into different focal points, which changes the physiology of vision due to the dispersion of light as it enters the eye. Modern multifocal IOLs provide a more physiological splitting of light and in this way optimize spectacle independence and also provide patients with better visual quality and fewer visual symptoms.

[0006] The foregoing examples of the related art and limitations associated therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those skilled in the art by reading the specification and studying the drawings. Summary of the invention

[0007] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools, and methods, which are intended to be exemplary and illustrative, not limiting in scope.

[0008] According to some embodiments of the present invention, a multifocal IOL is provided that includes at least one diffractive surface, the diffractive surface including a plurality of discrete, adjacent, diffractive concentric rings, the concentric rings having a radial phase profile cross-section with an approximately symmetrical diffractive surface topography, and an odd number of diffractive orders greater than 3. In some embodiments, the IOL includes an asymmetric distribution of energy flux across the diffractive orders.

[0009] In some embodiments, the IOL comprises 5 diffraction orders. In some embodiments, the diffractive surface comprises diffractive steps designed to maintain a diffractive profile constant between steps, and wherein the diffractive steps are partially within the base curvature of the IOL and partially outside the base curvature of the IOL.

[0010] In some embodiments, the diffractive, concentric rings comprise a repeating pattern of diffraction profiles. In some embodiments, the profiles are asymmetric.

[0011] In some embodiments, the diffraction ring comprises a repeating pattern of a single diffraction profile. In some embodiments, the diffraction ring comprises a repeating pattern of two different diffraction profiles, and wherein the diffraction ring comprises a single transition from a first region having a repeating pattern of one diffraction profile to a second peripheral region having a repeating pattern of a second diffraction profile.

[0012] In some embodiments, the height of the diffractive surface topography of the second peripheral zone remains constant when advancing radially outward relative to the center height of the IOL. In some embodiments, the radial phase profile cross section has an asymmetric double-peak geometry.

[0013] In some embodiments, the thickness of the IOL is variable and the curvature is maintained. In some embodiments, the thickness of the IOL is variable and the curvature is variable.

[0014] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0016] Exemplary embodiments are illustrated in the referenced drawings. The dimensions of components and features shown in the drawings are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. These drawings are listed below.

[0017] Figure 1A is a simplified example of a plan view of a multifocal IOL; and

[0018] Figure 1B is a simplified illustration of a cross-sectional view of a diffractive surface of a multifocal IOL according to some embodiments of the present invention.

[0019] Figure 2A is a simplified example of a radial, cross-section of a diffractive surface topography of a portion of an IOL; and

[0020] Figure 2B is with Figure 2A A distribution diagram of energy flux (power) levels at specific diffraction orders associated with the diffraction surface topography shown in FIG.

[0021] Figure 3A is a simplified example of a radial, cross-section of a diffractive surface topography of a portion of an IOL; and

[0022] Figure 3B is with Figure 3A Distribution of energy flux (energy) levels at specific diffraction orders related to the diffractive surface topography shown in .

[0023] Figure 4 is a diagram of superimposed two radial phase profiles according to some examples of the present invention;

[0024] Figure 5A is a simplified example of a radial cross section of the diffractive surface topography of a portion of an IOL;

[0025] Figure 5B is with Figure 5A A distribution diagram of energy flux (energy) levels at specific diffraction orders associated with the diffraction surface topography shown in FIG.

[0026] Figure 6 is a graph of a simulation of a through-focus modulation transfer function (MTF) of an IOL according to some embodiments of the present invention; and

[0027] Figure 7 is a simplified graphical example depicting the outline of the diffractive portion of an exemplary lens according to some embodiments of the current invention. DETAILED DESCRIPTION

[0028] As shown in the attached figure Figures 1A to 6 To better understand some embodiments of the present invention, reference is first made to the construction and operation of a multifocal intraocular lens (IOL), as exemplified in FIG.

[0029] Multifocal intraocular lenses (IOLs) are designed so that one, two, three or more diffraction orders or focal points are produced on the optical axis so that each image focus is formed on the retina when the object associated with the image is located at a corresponding distance from the eye. Most intraocular lenses are designed to have diffractive (lens) focal points and power fluxes (powers) corresponding to distance vision, i.e., the spherical / aspherical surfaces of the lens are designed to focus the image of the object on the retina when the object is located at the distance of distance vision from the eye (>5-6 meters). The diffractive surfaces in most bifocal and trifocal lenses create additional focal points at near distances (30-40cm) and intermediate distances (60-80cm).

[0030] Most refractive-diffractive IOLs have the same general structure - a lens containing multiple rings, each with a diffraction profile that expands to the width of the ring. The diffraction profile repeats along the radius of each Fresnel zone. In some cases, the rings also expand vertically (apodization).

[0031] According to aspects of the invention, an IOL is provided that includes diffractive steps that are partially within and partially outside the base curvature of the IOL. In some embodiments, the thickness of the IOL is variable and the curvature is constant. In some embodiments, the change in curvature is produced by optimizing the sphericity between steps.

[0032] According to aspects of some embodiments of the present invention, an IOL is provided having a spherical surface and an aspherical surface. In some embodiments, the IOL comprises an asymmetric number of active diffractive orders along the optical axis of the eye. In some embodiments, the IOL comprises more than three diffraction orders on the optical axis of the eye. In some embodiments, the IOL comprises 5 diffraction orders on the optical axis.

[0033] In some embodiments, the IOL includes a diffraction pattern on one or more surfaces of the lens. In some embodiments, the diffraction pattern includes a repeating pattern of a diffraction profile. In some embodiments, the profile is asymmetric.

[0034] Reference now Figure 1A and Figure 1B (not drawn to scale), where Figure 1A is a simplified example of a plan view of a multifocal IOL, and Figure 1B is a simplified illustration of a cross-sectional view of a diffractive surface of a multifocal IOL according to some embodiments of the present invention.

[0035] like Figure 1A As shown in the exemplary embodiment depicted in , an IOL 100 includes a diffractive surface having a plurality of discrete, adjacent, diffractive, concentric segments or rings 102.

[0036] In some embodiments, the IOL diffractive surface includes diffractive steps that are partially within the basic curvature of the IOL and partially outside the basic curvature of the IOL. This causes a change in diffraction state between two steps. In some embodiments, the thickness of the IOL is variable, but the curvature is maintained. In some embodiments, the change in curvature is produced by optimization of sphericity between steps.

[0037] The potential advantages of the described design are:

[0038] 1. The diffraction steps are designed so that they do not change the diffraction profile between steps. This allows for multifocal IOLs with any increased power and higher efficiency for near focal distances without loss of distance contrast.

[0039] 2. The design of the diffraction steps allows the light to be parallel to the steps, which is the ideal condition for diffraction.

[0040] In some embodiments, the rings are distributed along the Fresnel zones (102-1 / 102-2). In some embodiments, and as Figure 1B As shown in , the IOL surface 150 topography is characterized by a repeating triangular form, square form, or parabolic form, depending on the type of lens.

[0041] Reference now Figure 2A and Figure 2B , Figure 2A is a simplified example of a radial, cross-sectional view of the diffractive surface topography of a portion of an IOL, and Figure 2B is with Figure 2A Distribution of energy flux (energy) levels at specific diffraction orders related to the diffractive surface topography shown in .

[0042] Figure 2A A radial cross section of the diffractive surface topography of the entire concentric rings or radial phase profile 200 is depicted. The specific cross section of the radial phase profile is generated by using the Gerchberg-Saxton (GS) iterative algorithm. Figure 2A An exemplary embodiment of a radial phase profile cross section is depicted showing an asymmetric double-peak cross section with an approximately symmetrical local diffractive surface topography. The radial phase profile 200 is converted into a height distribution that is radially and parabolically integrated into each of the Fresnel zones (rings) of a diffractive lens having a specific focal length.

[0043] The authors of the present disclosure have discovered that a symmetrical local diffractive surface topography function combined with an odd number of diffraction diffractive orders (e.g., 1, 3, 5, 7, or 9 diffraction diffractive orders), and specifically, a number of diffraction diffractive orders greater than 3, increases the overall transmittance of the IOL by more than 90%, and in some cases up to at least 93%.

[0044] In some embodiments, the IOL 100 includes 5 diffraction orders on the optical axis. In some embodiments, one of the diffraction orders (e.g., the far vision focal length) has a high energy flux level. In some embodiments, one of the diffraction orders is completely suppressed. In some embodiments, the 5 diffraction orders or focal points correspond to the following 5 diffraction orders: -2, -1, +1, and +2 (which are the diffraction orders of diffraction produced by the diffraction pattern) and a single order 0 (which is the diffraction energy (refractive power) produced by the spherical / aspherical surface of the IOL). In some embodiments, the spherical / aspherical surface of the lens is designed so that when the imaged object is located at an intermediate distance from the eye, between near vision (about 30-40 cm) and far vision (several meters), the image is focused on the retina.

[0045] In some embodiments, and as Figure 2B As depicted in , among the 5 diffraction orders, diffraction order -2 corresponding to far vision has the highest energy flux level. In some embodiments, among the remaining diffraction orders, diffraction order +2 corresponding to near vision has the highest energy flux level. In this embodiment, diffraction order -1 is suppressed.

[0046] Reference now Figure 3A and Figure 3B , Figure 3A is a simplified example of a radial cross-section of the diffractive surface topography of a portion of an IOL, and Figure 3B is with Figure 3A A diagram showing the distribution of energy flux levels on specific diffraction orders related to the diffraction surface topography shown in .

[0047] Figure 3A and 3B Display design and Figure 2A and 2B The designs of the examples in are different, however both are designed using the same profile generation method using the Gerchberg-Saxton (GS) iterative algorithm, and the phase profile is converted into a height distribution, which is radially and parabolically integrated into each of the Fresnel zones (rings) of the diffractive lens with a specific focal length.

[0048] Figure 3A Another example of a radial cross section or radial phase profile 300 of the diffractive surface topography of the entire concentric rings is depicted. Figure 3A An exemplary embodiment of a radial phase profile is depicted, showing an asymmetric double-peak cross section with an approximately symmetric local diffractive surface topography. The radial phase profile 300 is converted into a height profile that is radially and parabolically integrated into each of the Fresnel zones (rings) of a diffractive lens having a specific focal length.

[0049] In some embodiments, and as Figure 3B As depicted in , among the 5 diffraction orders, diffraction order -2 corresponding to far vision has the highest energy flux level. In some embodiments, among the remaining diffraction orders, diffraction order +2 corresponding to near vision has the highest energy flux level, and the energy flux level at order 0 is higher than the energy flux level at diffraction order +1. In this embodiment, diffraction order -1 is suppressed.

[0050] like Figure 4 , which is a diagram of radial phase profile 300 superimposed on radial phase profile 200, illustrating the phase differences between designs according to some examples of the present invention. When this technique is used with more than 5 focal points (e.g., 7), the diffraction focal length determines the location of the far focus (diffraction order -3) and the near focus (diffraction order +3), and the refractive focal length (spherical surface) determines the location of one of the intermediate foci (order 0). Figure 4 In the exemplary embodiment depicted in FIG. 1 , radial phase profile 200 includes phases: 1, 0, 0.333, 0.38, and 0.637, wherein radial phase profile 300 includes phases: 1, 0, 0.6, 0.45, and 0.65. In some embodiments, the IOL includes two zones - central zone 102-1 ( Figure 1A and Figure 1B ) and peripheral zone 102-2. In some embodiments, the diffraction pattern of the central zone 102-1 is not progressive. In some environments, the diffraction pattern of the peripheral zone 102-2 is not progressive. When moving radially outward relative to the center height of the IOL, the height of the diffractive surface topography of zone 102-2 remains constant and does not have a gradual step height reduction. This arrangement and design is planned by diffraction order to change the intensity distribution when increasing aperture and allow for increased light throughput in the case of pupil dilation (low intensity ambient) light, even if it is not optimally focused.

[0051] A potential advantage of this design is that the progressive design allows for close to 100% diffraction efficiency, thus minimizing light losses.

[0052] To modify the intensity distribution according to the aperture size, the technique used herein is to change the diffraction pattern at any radius of the intraocular lens or one of the Fresnel zones (or near one of them) for better performance. For the present invention, the design switch occurs at a radius of about 1.228 mm.

[0053] like Figure 5A and 5B As shown in Figure 5A An example of a radial cross-section or radial phase profile 500 depicting the diffractive surface topography of an entire concentric ring of a peripheral zone of an IOL according to some embodiments of the present invention. Figure 5AAn exemplary embodiment of a radial phase profile cross section at the IOL peripheral zone 102-2 is depicted, showing an asymmetric single-peak cross section with an approximately symmetric local diffractive surface topography.

[0054] In some embodiments, the radial phase profile cross section at the IOL peripheral zone 102-2 comprises an asymmetric double-peak cross section with an approximately symmetric local diffractive surface topography. The radial phase profile 500 is converted into a height profile that is radially and parabolically integrated into each of the Fresnel zones (rings) of the diffractive lens having a specific focal length.

[0055] In some embodiments, and as Figure 5B As depicted in , the flux energy level decreases from the far diffraction orders to the near diffraction orders, with two suppressed orders at -1 and +1.

[0056] obtained at the source plane and Figure 5A and 5B The phases used in the design depicted in (at radii > 1.228 mm) were obtained using the normalized target intensities [1, 0, 0.5, 0, 0.34] in the Gerchberg-Saxton (GS) algorithm.

[0057] However, in some embodiments, the other diffraction profile (after conversion) can be a different diffraction design based on three or more foci, and can also be a monofocal design with full power in distance vision or a bifocal with power in distance vision, and other foci in intermediate vision or near vision.

[0058] Likewise, the entire diffraction height profile (before and after the transition from IOL zone 102-1 to IOL zone 102-2) may be tunable for tuning of the intraocular lens. Figure 5A and Figure 5B In the exemplary embodiment depicted in , the first diffraction profile before conversion increased by 5%, while the second diffraction profile after conversion increased by 12%. Based on the zeroth order for intermediate vision, our multifocal IOL has a high efficiency of more than 90% in the used diffraction orders (-2, -1, 0, 1, 2).

[0059] Reference now Figure 6 , Figure 6 5 , three graphs are plotted for three levels of eye pupil diameter: graph 602 for a 2 mm pupil diameter (i.e., bright light conditions), graph 604 for a 4.5 mm pupil diameter (i.e., dim light conditions), and graph 606 for a 3 mm pupil diameter (i.e., normal light conditions).

[0060] Figure 6 The graphs depicted in exemplify the biphasic nature of the IOL at all three ambient light levels shown, however, as the ambient light level decreases, the pupil diameter changes from 2 mm to 4.5 mm, and the MTF value increases accordingly over the distance vision range of the IOL, even though it is restricted from the diopter range between approximately 22 and 24.5 to a narrower diopter range between approximately 23 and 23.75, and allows for improved low light intensity vision.

[0061] Figure 7 is a simplified diagrammatic example depicting the outline of the diffractive portion of an exemplary lens according to some embodiments of the current invention. Figure 7 As shown in , the depicted cross-sectional profile includes an asymmetric unimodal morphology comprising multiple peaks having heights dispersed between 1.5 and 2.5 uM along a portion of the lens radius between 0 and 3000 uM.

[0062] Throughout this application, various embodiments of the present invention can be presented in a range format. It should be understood that the description of the range format is only for convenience and simplicity, and should not be interpreted as an inflexible limitation to the scope of the present invention. Therefore, the description of the range should be considered as having specifically disclosed all possible sub-ranges and each numerical value in the range. For example, the description of the range (such as from 1 to 6) should be considered as having specifically disclosed sub-ranges (such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc.), and a single number (such as 1, 2, 3, 4, 5 and 6) in the range. Regardless of the breadth of the scope, this applies.

[0063] Whenever a numerical range is indicated herein, it is intended to include any cited numeral (fractional or integer) within the indicated range. The phrases "ranging / ranges between a first indicated numeral and a second indicated numeral" and "ranging / ranges from a first indicated numeral to a second indicated numeral" are used interchangeably herein and are intended to include the first and second indicated numerals and all fractions and integers therebetween.

[0064] In the specification and claims of the present application, each of the words "comprise", "include" and "have" and their forms are not necessarily limited to the members of the list associated with these words. In addition, in the event of inconsistencies between the present application and any documents incorporated by reference, the present application is intended to control.

[0065] Descriptions of various embodiments of the present invention have been given for purposes of illustration, but these descriptions are not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, practical applications or technical improvements of technologies found in the marketplace, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. Multifocal IOL, which includes: at least one diffractive surface comprising a plurality of discrete, adjacent, diffractive concentric rings having: a radial phase profile cross section with an approximately symmetrical local diffractive surface topography; and An odd number of consecutive diffraction orders greater than 3, centered around the 0th order, in: The IOL is characterized by an asymmetric distribution of energy flux over the continuous diffraction orders, wherein only diffraction order -1 is suppressed among the continuous diffraction orders; The diffractive concentric rings include a single transition from a first central region having a repeating pattern of one diffractive profile to a second peripheral region having a repeating pattern of a second diffractive profile.

2. The IOL of claim 1, wherein the IOL comprises 5 diffraction orders.

3. The IOL of claim 1, wherein the diffractive surface comprises diffractive steps designed to keep the diffractive profile constant between the steps.

4. The IOL of claim 3, wherein the diffractive steps are partially within the base curvature of the IOL and partially outside the base curvature of the IOL. The IOL of claim 1 , wherein the profile is asymmetric.

6. The IOL of claim 1, wherein the height of the diffractive surface topography of the second peripheral zone remains constant when advancing radially outward relative to the center height of the IOL.

7. The IOL of claim 1, wherein the radial phase profile cross section has an asymmetric bimodal geometry.

8. The IOL of claim 4, wherein the thickness of the IOL is variable and the curvature is maintained.

9. The IOL of claim 4, wherein the thickness of the IOL is variable and the curvature is variable.

10. The IOL of claim 1, wherein the overall light transmittance of the IOL is above 90%.

11. The IOL of claim 10, wherein the overall light transmittance is at least 93%.

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