Ophthalmic lens for myopia control

Abstract

An ophthalmic lens and a system for designing a lens. The lens includes a lens center and a shape defined by a lens peripheral edge. An optical zone surrounds the lens center and has an optical zone outer perimeter, the optical zone having a diopter selected to correct a myopic condition of a user. The toric power of the lens at the center of the lens is less than the toric power at the outer periphery of the optical region, and has a variable toric power that increases radially across at least a portion of the lens to at least the outer periphery of the optical region. The variable toric power has a predetermined power profile that causes a front field of view average blur anisotropy of the user at or in front of the retinal plane of the user.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 434,819 filed on December 22, 2022 and U.S. Provisional Application No. 63 / 548,432 filed on November 14, 2023. Technical Field

[0003] The present application relates to an ophthalmic lens designed to prevent or reduce myopia progression in a patient. More specifically, the present application relates to lens designs and methods for lens designs that induce a predetermined peripheral blur orientation at the retinal plane or otherwise increase the average peripheral blur anisotropy value. Background Art

[0004] Common conditions that lead to decreased visual acuity include myopia and hyperopia, for which corrective lenses in the form of glasses, rigid or soft contact lenses are worn. These conditions are generally described as an imbalance between the length of the eye and the focus of the optics of the eye. Myopic eyes focus light from distant objects in front of the retinal plane, and unaccommodated hyperopic eyes focus light from distant objects behind the retinal plane. Myopia usually develops because the axial length of the eye grows longer than the focal length of the optics of the eye, i.e., the eye grows too long. Hyperopia usually develops because the axial length of the eye is too short compared to the focal length of the optics of the eye.

[0005] Myopia has a high prevalence in many parts of the world. The most concerning condition is its potential to develop into high myopia, e.g., greater than five (5) or six (6) diopters, which significantly affects a person's ability to function without optical aids. High myopia is also associated with an increased risk of retinal disease, cataracts, glaucoma, and myopic macular degeneration (MMD, also known as myopic retinopathy), and may become the leading cause of permanent blindness worldwide. MMD has been associated with refractive error (RE) to the point where it is not possible to clearly distinguish between pathological and physiological myopia, and therefore there is no "safe" level of myopia.

[0006] Corrective lenses are used to change the overall focus of the eye so that a sharper image is formed at the retinal plane by shifting focus from the front of the plane to correct myopia or from the back of the plane to correct hyperopia, respectively. However, the corrective approaches to these conditions do not address the cause but are merely remedial or aimed at treating the symptoms.

[0007] Most eyes do not have simple myopia or hyperopia, but also have myopic astigmatism or hyperopic astigmatism. The astigmatic error of focusing causes the image of a point light source to be formed as two mutually perpendicular lines at different focal lengths. In the following discussion, the terms myopia and hyperopia are used to include simple myopia and myopic astigmatism and simple hyperopia and hyperopic astigmatism, respectively.

[0008] Emmetropia describes a state of clear vision in which objects at infinity are in relatively sharp focus when no optical correction is required and the lens is relaxed. In a normal or emmetropic adult eye, light from distant and near objects passing through the central or paraxial region of the aperture or pupil is focused by the lens into the eye close to the retinal plane where an inverted image is sensed. However, it has been observed that most normal eyes exhibit positive longitudinal spherical aberration, meaning that light passing through the aperture or pupil at its periphery is focused in front of the retinal plane when the eye is focused to infinity. As used herein, the measurement D is the dioptric power, which is defined as the reciprocal of the focal length of a lens or optical system, expressed in meters.

[0009] The spherical aberration of a normal eye is not constant. For example, accommodation (a change in the refractive power of the eye produced primarily by changes in the internal lens) causes the spherical aberration to change from positive to negative.

[0010] As noted, myopia generally occurs due to excessive axial growth or elongation of the eye. It is now generally accepted that the focus and quality of the retinal image can affect axial eye growth, and that altering the retinal image can cause consistent and predictable changes in eye growth.

[0011] Known methods of attempting to eliminate or reduce axial elongation of the eye, particularly in children, include the application of ophthalmic lenses that intentionally introduce myopic defocus in the visual field. Myopic defocus introduces a "stopping" stimulus to the eye that produces a restriction on eye growth. This was initially observed as a thickening of the choroid. It has been shown in animal studies that changes in eye growth in response to retinal image defocus are largely mediated through local retinal mechanisms, because changes in eye length still occur when the optic nerve is damaged, and because it has been shown that imposing defocus on a localized retinal area results in changes in eye growth that are localized to that specific retinal area.

[0012] Ophthalmic lenses with a concentric ring design have been shown to slow myopia progression. These ophthalmic lenses include the Johnson & Johnson Vision Care, Inc. Bifocal lenses and CooperVision, Inc. Contact lenses. These lenses have certain annular zones containing optics that correct myopia, while others introduce myopic defocus. Light from a distant object along the optical axis that passes through a given annulus comes into focus substantially at a point on the optical axis; on the retina and in front of the retina for the myopic correction annulus and the myopic defocus annulus, respectively.

[0013] U.S. Patent No. 10,901,237, which is incorporated herein by reference in its entirety, describes various other lens designs for myopia control, particularly for use in soft contact lenses. These lenses also have a concentric annular design in which certain annular segments include optical devices that focus on the retina. For patients who need myopia correction, these annular segments may include optical devices that redirect the focus to the retina. For patients who do not need myopia correction, these annular segments may not provide optical correction. The myopic defocus annular segment that is not centrally positioned contains an optical device that focuses light passing therethrough in front of the retina, rather than a point focus on the optical axis, which forms a non-coaxial annular focus. In some disclosed embodiments, the central portion of the lens contains an add optical power that causes myopic defocus but along the optical axis.

[0014] Lens designs such as these tend to emphasize on-axis optics from light rays originating from objects along the optical axis, and more specifically produce a focus relative to the central area. In addition, these lens designs focus on design principles based on central vision, and incorporate optical elements into the central vision area to produce myopic defocus. In addition to central vision, it has been shown that peripheral refractive error can have a substantial impact on central refractive development, and myopic defocus in the near periphery can slow axial growth. See Smith, Vision Reg., Sept. 2009; 49(19): 2386-2392).

[0015] Additional aberrations occur in peripheral vision, which may further contribute to the development of myopia. In an astigmatic eye, the refraction of the eye is not spherical or rotationally uniform, but because of the elliptical or "football" shape of the eye, the refractive power along one meridian is different from the refractive power along the vertical meridian, so that the focal lines along the two meridians are at different distances. Regular astigmatism is generally classified as "with the rule," "against the rule," or "oblique axis." For individuals with "with the rule" astigmatism (the most common), the vertical meridian has the strongest optical power or steepest curvature compared to the horizontal meridian. Oblique axis astigmatism occurs when the strongest optical power or steepest curvature does not fall on the vertical or horizontal meridian.

[0016] In addition to the possible presence of astigmatism in central vision, it is well known that peripheral astigmatism is produced by light rays striking the refractive surfaces of the cornea and lens at oblique incidence. This astigmatism and other wavefront aberrations result in highly anisotropic optical blur in the peripheral retina. Blur anisotropy is defined herein as the logarithm (base 10) of the ratio of the area under the modulation transfer function (MTF) along the vertical meridian (superior-inferior meridian) divided by the area under the MTF along the horizontal meridian (temporal-nasal meridian), i.e., blur anisotropy = log[(area)] 竖直 / (area) 水平 ]. Thus, blur anisotropy is negative when the image (or point spread function) has primarily vertically oriented blur, and is positive when the image has primarily horizontally oriented blur. The human nervous system is more sensitive to horizontally oriented visual stimuli than to vertically oriented stimuli. Furthermore, the orientation of the blur pattern produced by astigmatism changes from horizontal to vertical movement around the periphery of the retina, a principle known as the meridian effect.

[0017] Figure 2 An exemplary illustration of peripheral blur anisotropy is shown in , where the blur at the retinal plane has an asymmetric pattern such that the blur pattern is longer in one direction (i.e., along the y-axis) than in the perpendicular direction. Figure 2 In the embodiment of the present invention, the optical resolution along the x-axis will be finer than the optical resolution along the y-axis. As described above, the orientation of the peripheral blur will change around the periphery of the retina.

[0018] Peripheral vision can also be used to introduce myopia control effects. In a recent publication entitled "Eccentricity-Dependent Effects of Simultaneous Competing Defocus on Emmetropization in Infant Rhesus Monkeys" (Vision Research 177 (2020) 32-40), the authors showed that myopic defocus of about 20° from the fovea can significantly affect the development of central refraction in primates. In another publication, it is assumed that the orientation sensitivity of the nervous system is consistent with the habitual fuzzy orientation, and this fuzzy orientation may be a trigger for eye growth. Zhelenznyak et al. (2016), Optical and Neural Ansiotropy in Peripheral Vision, Journal of Vision, 16 (5): 1, 1-11.

[0019] Recently, Ji et al. used modeling techniques to evaluate certain bifocal and multifocal contact lenses that are suitable for incorporating additional optical power for inducing myopic defocus compared to monofocal lenses to evaluate the effect of the lenses on peripheral vision at various eccentricities. Ji et al., Through-focus Optical Characteristics of Monofocal and Bifocal Soft Contact Lenses Across the Peripheral Visual Field, Ophthalmic & Physiological Optics, 38 (2018) 326-336. The results of the study indicate that when compared with single-vision lenses, the first two lenses exhibit a reduction in the anisotropy of peripheral optical blur and an increase in depth of focus. Thus, the authors hypothesize that the mechanism for controlling myopia with bifocal and multifocal lenses is a reduction in the anisotropy of peripheral optical blur and an increase in depth of focus.

[0020] U.S. Patent Publication No. 2022 / 0252901 to Yoon (“Yoon”) describes an optical lens for myopia control that intentionally introduces peripheral aberrations for the purpose of manipulating peripheral blur to make the peripheral blur more radially symmetric. In other words, based on the early assumption in Ji’s paper that it is desirable to reduce the anisotropy of peripheral optical blur, the application describes the purpose of intentionally minimizing the anisotropy in the peripheral region to a point where the anisotropy is radially symmetric, such as, for example Figure 1 In other words, the lens described in Yoon preferably has a circle of least confusion at the patient's retina. This means that one focal line is behind the retina and one focal line is in front of the retina. In contrast, the lens described herein prefers that both the tangential and sagittal focal lines are in front of the retina or have an adjusted blur anisotropy value toward the positive direction.

[0021] The present inventors have discovered that, contrary to the teachings of Yoon and Ji, lenses designed to have high blur anisotropy oriented opposite to that of peripheral hyperopia exhibit better myopia control treatment efficacy. Utilizing these findings, lens designs incorporating peripheral optics that increase the average peripheral blur anisotropy value (towards the positive direction) will also improve efficacy. The present disclosure relates to such lens designs and methods for designing such lenses. Summary of the invention

[0022] An ophthalmic lens is provided, the ophthalmic lens having a lens center and a shape defined by a lens peripheral edge. An optical zone surrounds the lens center and has an optical zone outer periphery, and has a diopter selected to correct a myopic condition of a user of the lens. The lens has a toric optical power at the lens center that is less than the toric optical power at the optical zone outer periphery, and has a variable toric optical power that increases radially across at least a portion of the lens to at least the optical zone outer periphery. The variable toric optical power has a predetermined optical power profile that causes an emmetropia average blur anisotropy for the user at or in front of a retinal plane of the user.

[0023] The field average blur anisotropy can be positive at the retinal plane across a 0 degree to 40 degree field of view, and the variable toric power can increase continuously from the center of the lens to the outer periphery of the optical zone.

[0024] In one embodiment, the variable toric power is given by the equation: Toric Power = 0.0642(r) 3 –0.1063(r) 2 –0.018(r) definition, where r is equal to the radius from the center of the lens.

[0025] The lens may also include a lens center region centered about the lens center within the optical zone and having a lens center region diameter. The lens center may have zero toric power in the lens center region, and the variable toric power may extend radially outward from the lens center region to the outer periphery of the optical zone. The lens center region diameter may be designed to match an average pupil diameter of a predetermined population and may be between 3 mm and 5 mm.

[0026] In yet another embodiment, the variable toric power distribution between the central region of the lens and the outer periphery of the optical zone is interrupted by at least one radial segment, the toric power being zero across the at least one radial segment, and the variable toric power distribution may be interrupted by a first radial segment and a second radial segment, the toric power being zero across the first radial segment and the second radial segment.

[0027] The myopia control efficacy of the lens may be greater than that of a comparable spherical single vision lens of the same power without the variable toric power profile.

[0028] The lens may be a contact lens, a spectacle lens, an intraocular lens, or a phakic lens.

[0029] The variable toric power profile may be on the front surface of the lens or on the back surface of said lens.

[0030] A method for designing an ophthalmic lens is also provided, the method comprising the steps of creating a lens design having a lens center and a shape defined by an outer edge of the lens, and an optical zone surrounding the lens center and having an outer periphery of the optical zone. The refractive power of the optical zone is selected to correct myopic vision of a person. The method also comprises the steps of applying a variable toric power profile across at least a portion of the optical zone of the lens to the lens design, wherein the variable toric power profile has toric power that increases radially from the lens center and is configured to induce an emmetropia average blur anisotropy in the person at or in front of the retinal plane of the person.

[0031] The field average blur anisotropy may be positive at the retinal plane across a 0 degree to 40 degree field of view.

[0032] According to one embodiment, the variable toric power increases continuously from the center of the lens to the outer periphery of the optical zone. The variable toric power can be expressed by the equation: toric power = 0.0642 (r) 3 –0.1063(r) 2 –0.018(r) definition, where r is equal to the radius from the center of the lens.

[0033] In yet another embodiment, the lens design further comprises a lens central region within the optical zone and centered at the lens center, wherein the lens has zero toric optical power within the lens central region. The diameter of the lens central region may be between 3 mm and 5 mm.

[0034] In another embodiment, the variable toric power profile between the central region of the lens and the outer periphery of the optic zone is interrupted by at least one radial segment across which the toric power is zero.

[0035] The myopia control efficacy of the lens may be greater than that of a comparable spherical single vision lens of the same optical power but without the variable toric power profile.

[0036] The lens may be a contact lens, a spectacle lens, an intraocular lens, or a phakic lens.

[0037] The variable toric power profile may be on the front surface of the lens or on the back surface of said lens.

[0038] A contact lens for slowing progression of myopia in a wearer is also provided, comprising: a single vision lens having a lens center and a shape defined by a lens peripheral edge, an optical zone surrounding the lens center within the lens peripheral edge and defined by an optical zone outer periphery, wherein the optical zone has a predetermined refractive power selected to correct the wearer's myopia condition; and a variable toric power profile applied to at least a portion of the optical zone. The toric power profile is configured to induce an emmetropia average blur anisotropy in the wearer at or in front of the wearer's retinal plane.

[0039] The field average blur anisotropy may be positive at the retinal plane across a 0 degree to 40 degree field of view.

[0040] The toric power profile may be a variable toric power profile that increases radially from the center of the lens, and may further increase continuously from the center of the lens to at least the outer periphery of the optical zone. In one embodiment, the variable toric power is given by the equation: Toric Power = 0.0642 (r) 3 –0.1063(r) 2 –0.018(r) definition, where r is equal to the radius from the center of the lens.

[0041] The lens may further include a lens central region centered about the lens center and within the optical zone and having a lens central diameter, wherein the lens has zero toric power in the lens central region and the variable toric power extends radially outward from the lens central region to at least the outer periphery of the optical zone. The lens central diameter may substantially match an average pupil diameter of a predetermined population and may be between 3 mm and 5 mm.

[0042] In one embodiment, the variable toric power distribution between the central region of the lens and the outer periphery of the optical zone is interrupted by at least one radial segment, the toric power being zero across the at least one radial segment, and the variable toric power distribution may be further interrupted by a first radial segment and a second radial segment, the toric power being zero across the first radial segment and the second radial segment.

[0043] The myopia control efficacy of the lens may be greater than that of a comparable spherical single vision lens of the same refractive power but without the variable toric power profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The foregoing and other features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

[0045] Figure 1An anisotropic peripheral blur pattern is illustrated; wherein the illustrated pattern is generated by ray tracing through a model eye, wherein each cross represents the intersection of a ray with the retina, and wherein rays originating from a point source are uniformly distributed throughout the pupil.

[0046] Figure 2 An anisotropic peripheral blur pattern is illustrated, where the illustrated pattern is generated by ray tracing through a model eye, where each cross represents the intersection of a ray with the retina, and where rays originating from a point source are evenly distributed throughout the pupil.

[0047] Figure 3 An eye model for simulating central and peripheral vision is illustrated;

[0048] Figures 4(a) to 4(d) illustrate blur anisotropy values ​​for various lenses;

[0049] Figure 5 illustrates a toric power profile for a lens according to the present invention;

[0050] Figure 6 Illustrated for Figure 5 The blur anisotropy value of the lens;

[0051] Figure 7 4 and Figure 5 The myopia control efficacy value of the lens;

[0052] Figure 8 The lower limbal ray position relative to the center of the eye is illustrated for various pupil sizes;

[0053] Fig. 9 illustrates a toric power profile for an alternative lens according to the present invention;

[0054] Fig.10 Exemplary lenses to which the present invention may be applied are illustrated;

[0055] Fig.11 illustrates a power profile for a lens incorporating peripheral optical features according to the present disclosure;

[0056] Figures 12a and 12b illustrate the results of the experiment for the 4 mm pupil size condition. Fig.11 The fuzzy anisotropy value of the implementation scheme;

[0057] Figures 13a and 13b illustrate the results of the experiment for the 5 mm pupil size condition. Fig.11 The fuzzy anisotropy value of the implementation of

[0058] Figures 14a and 14b illustrate blur anisotropy values ​​for the lenses of Figures 4b and 4d at a 5 mm pupil size. DETAILED DESCRIPTION

[0059] The present disclosure relates to ophthalmic lens designs and methods for ophthalmic lens designs that induce directional peripheral blur to increase myopia control efficacy. The present disclosure also relates to ophthalmic lens designs and methods for lens designs that introduce optical elements or features that increase the average peripheral blur anisotropy value into the peripheral optical zone, thereby increasing myopia control efficacy or otherwise providing a better balance of efficacy and visual acuity. Ophthalmic lenses to which the present disclosure is applicable include, but are not limited to, contact lenses, spectacle lenses, and implantable ophthalmic lenses, such as intraocular lenses and phakic lenses, that are worn on the eyes of a person or wearer.

[0060] Variable toric design

[0061] As described above, typical human vision provides a focused image in the central vision area and provides increasingly anisotropic blurred images toward the periphery of the eye. For individuals who need correction (nearsightedness or farsightedness), ophthalmic lenses focus on correction of central vision, which is typically within about 10 degrees of the line of sight. Figure 3 An eye model showing a field of view (FOV) ranging from 0 to 40 degrees is illustrated. This eye model used herein to evaluate peripheral blur is similar to the model described in detail by Navarro et al. in the publication J.Opt.Soc.Am.A 16, 1881-1891 (1999), which is incorporated herein by reference. Based on the use of actual biometric data, the model has been modified to include only slight changes in the corneal and lens surfaces of the model. The eye model is constructed to represent the average eye optical and mechanical properties of the general population, including wavefront aberrations, corneal anterior curvature, etc. The eye model is also used for visual interference (scattering) simulation, as described by Chen in the publication Evaluating the Effects of Scattering on Retinal Image Quality, Proc.SPIE 11941, Ophthalmic Technologies XXXII, 119410B (March 4, 2022).

[0062] It is known to those skilled in the art that in a typical eye, blur increases at larger peripheral FOV angles. It is further known from the meridian effect that the orientation of the blur pattern changes around the periphery. In addition, along the horizontal meridian, higher FOV angles of horizontal gratings being viewed perform better than higher FOV angles of vertical gratings when compared to central vision seeing a substantially similar image.

[0063] As also described above, Ji hypothesized that eliminating or minimizing peripheral blur orientation (producing an isotropic blur pattern) would improve myopia control efficacy in a lens. Contrary to this teaching, the inventors herein have discovered that inducing an anisotropic blur pattern formed by myopic astigmatism is desirable and more effective.

[0064] To quantitatively assess peripheral image blur orientation, several myopia control lenses were evaluated using the model described above under 4 mm pupil conditions, including the 1000X 1000X from Johnson & Johnson Vision Care, Inc. Abiliti TM Figures 4a-4b illustrate the blur anisotropy of these lenses as evaluated, with a single vision lens ("Lens 1") shown in Figure 4a, Abiliti TM The lens ("lens 4") is shown in Figure 4d, similar to Abiliti TM A first test lens without a high add power central treatment zone is shown in FIG. 4b (“Lens 2”), and a second bifocal test lens with dual coaxial foci is shown in FIG. 4c (“Lens 3”). The blur anisotropy is negative when the image has a vertical orientation, and positive when the image has a horizontal orientation. Within each figure, the blur anisotropy at 0, 10, 20, 30, and 40 degree FOVs is shown by reference numerals 400, 410, 420, 430, and 440, respectively. For each figure, the vertical line at x=0 represents the retinal plane or zero defocus, and the horizontal axis indicates defocus in front of (positive) or behind (negative) the retina. As shown in these figures, for all lenses, except for the lens of FIG. 4d at 10 degree FOV, the blur anisotropy at the retinal plane is negative for all degree FOVs except zero.

[0065] As shown in Figures 4a to 4d, at the peripheral field of view, the blur anisotropy shows maximum and minimum values ​​both in front of the retina and behind the retina, which corresponds to the focal line of astigmatism. For the single vision lens shown in Figure 4a, the size and position of the focal line at the retina vary significantly, and are -0.13, -0.35, -0.41 and -0.89 for 10, 20, 30 and 40 FOV, respectively. The FOV average blur orientation value at the retinal plane is -0.44 (calculation does not include the foveal vision at 0 degree FOV). The FOV average blur anisotropy values ​​of the myopia control lenses of Figures 4b, 4c and 4d have higher values ​​of -0.16, -0.18 and -0.11, respectively. Figures 14a and 14b illustrate the blur anisotropy values ​​for the lenses of Figures 4b and 4d under the condition of 5 mm pupil size.

[0066] These increasingly positive FOV average blur anisotropy values ​​are associated with increased myopia control efficacy, as demonstrated in clinical studies using these same lenses. The clinical study results are summarized below, where the single vision lens (SV) corresponds to lens 1, the "concentric ring bifocal" lens (DF) corresponds to lens 3, the test lens EE (enhanced efficacy) corresponds to lens 4, and the test lens EV (enhanced vision) corresponds to lens 2. This clinical study is a multinational, prospective, randomized, controlled, double-blind, stratified, myopia-controlled clinical trial (NCT03408444). The purpose of the study is to compare the efficacy and visual acuity of the four lenses. A total of 185 patients completed the study. All study participants were aged 7-12 years, each participant had a spherical error ranging from -0.75D to -4.50D, astigmatism <=1.00D, and anisometropia <1.5D. As shown in the table below, there were no statistically significant differences in baseline characteristics between study participants.

[0067]

[0068] The efficacy of the lenses was determined by measuring the axial length (using the LENSTAR system) and assessing the ciliary muscle paralysis spherical equivalent autorefraction (SECAR) using the Grand Seiko WAM-5500 device, with five repeated measurements, each being the average of 3 consecutive readings.

[0069] The study concluded that all three study lenses were effective in slowing axial elongation of the eye compared to SV. The efficacy results of this study are shown below.

[0070]

[0071] Figure 2 Unadjusted mean (standard error) change over time in (A) axial length (AL) and (B) spherical equivalent ciliary muscle paralysis autorefraction (SECAR) by lens type. The 2 measurements of AL at 26 weeks represent the non-ciliary muscle paralysis measurement (dark gray) and the post-ciliary muscle paralysis measurement (black).

[0072] D = diopter; EE = enhanced efficacy lens group; EV = enhanced vision lens group; DF = dual focus lens group; SV = single vision lens group.

[0073] In the above Figure 2 In A, the top row represents single vision (SV) lenses, the next row represents dual focus (DF) lenses, the next row represents EV, and the bottom row represents EE lenses. Figure 2 In B, the top row is lens EE, the next row is lens DF, the next row is lens EV, and the bottom row is lens SV.

[0074] These results indicate that higher blur anisotropy values ​​are associated with better myopia control efficacy. The lenses described herein are designed to produce positive FOV average blur anisotropy values, rather than the negative values ​​exhibited in known myopia control (and spherical) lens designs, and in contrast to the near-zero blur anisotropy targets in the lenses described in the Yoon patent publications.

[0075] At its most general level, the lenses of the present application are able to achieve improved myopia control efficacy in single vision lenses by simply introducing variable toric power into the lenses. The term toric here is not used in the more commonly applied meaning used in optical devices for correcting central refractive astigmatism. In one embodiment, variable toricity is described in the spatial domain by introducing an aspheric surface to increase the amount away from the center of the optical device, and the variable toricity can produce changes in the oblique axis astigmatism that is usually produced in such devices. In another embodiment, variable toricity is described in the angle / FOV domain by introducing an aspheric surface to increase the amount away from the center FOV, and the variable toricity can produce changes in the oblique axis astigmatism that is usually produced in such devices. It is the toric power distribution itself that introduces the myopia control effect. Therefore, the lenses of the present invention achieve a level of myopia control efficacy using a lens design that is less complex than currently available myopia control lenses.

[0076] One lens design according to the present invention includes different curvatures in sagittal and tangential orientations to produce a variable toric power across the lens. For clarity, "variable toric power" as used herein with respect to an ophthalmic lens means a lens having a toric power that varies radially from the center of the lens outward across the optical zone of the lens, or at least a portion of the optical zone, according to a predetermined toric power profile. The variable toric power may be applied to the anterior or posterior surface of the lens as a continuously variable toric power, or may be applied discontinuously at certain radial locations as will be further described below.

[0077] The principles described herein can be readily applied to various types of ophthalmic lenses. In the case of contact lenses, Fig.10. An exemplary lens is shown in FIG. A contact lens 1000 includes a lens center 1002 and a shape defined by a lens peripheral edge 1003, and an optical zone 1004 surrounding the lens center and having an optical zone outer periphery 1006. The optical zone of a lens is generally considered to be a portion of the lens through which the wearer will view during the normal process of wearing the lens to receive the intended visual correction. For example, for a myopic patient, the optical zone may have a -3D optical power to correct the patient's myopic vision. The optical zone may have a circular configuration defined by a radius (r) from the center of the lens. In an alternative, the optical zone may take any other suitable shape, such as being particularly suitable for eyeglass lenses rather than contact lenses. The optical zone may be a single-vision optical zone (having a single diopter), or the optical zone may include other areas within the optical zone, such as a specific myopia treatment area as further described below. Although the diameter may vary, the optical zone in a contact lens is generally designed to be as large as possible without compromising mechanical properties (including handling and comfort), and the diameter is generally in the range of 6mm-10mm.

[0078] In the case of a myopia control lens, the optical zone may also optionally include one or more additional myopia treatment areas 1010, such as a high ADD power area at the very center of the lens. Although not necessary for myopia control as further described below, such an area can increase the efficacy of the lens because the relative ADD power causes myopic blurring so that the focus falls in front of the retina and, as will be readily understood by those skilled in the art, provides a stimulus to move the retina toward the point of myopic defocus. This in turn provides a counter signal to counteract further elongation of the eye or progression of myopia.

[0079] Although the above-described embodiments include a high ADD power zone at the center of the lens, any suitable configuration or positioning of one or more additional myopia treatment zones may be used, whether centrally positioned or not, and whether on-axis (the myopic defocus point falls on the optical axis but in front of the retina) or off-axis (the myopic defocus point is in front of the retina but not coincident with the optical axis).

[0080] In one embodiment, the contact lens has an aspheric back curvature with a radius of 7.85 and a conic constant of -0.26. The front surface has a biconical structure that is specifically designed so that the toric power increases steadily radially outward from zero at the center of the lens to the edge of the lens, such as Figure 5 It is noted that for this exemplary embodiment, the toric power of the lens is increased in a predetermined manner such that the blur anisotropy at or in front of the retina becomes positive. Figure 5 The illustrated variable toric power profile is given by the equation Toric Power = 0.0642(r) 3 –0.1063(r) 2–0.018(r) definition, where r is equal to the radius from the center of the lens.

[0081] When the blur anisotropy values ​​of the lens described above at 0, 10, 20, 30 and 40 degree FOV are modeled in the same manner as described above for the lens of Figures 4a to 4d, the results are Figure 6 4a to 4d (lines 600, 610, 620, 630 and 640 respectively). As shown, the blur anisotropy values ​​at the retinal plane (x=0) are all positive compared to the lens shown in FIGS. 4a to 4d, demonstrating that this lens induces an opposite blur orientation relative to the comparison lens.

[0082] The efficacy of a positive blur inducing lens according to the present invention was mathematically tested using the peripheral blur model described above, compared to the lens discussed in conjunction with Figures 4a-4d. "Lens 5" is a lens of the present invention that is identical to Lens 1 discussed above (a single vision (SV) lens with -3D power), but has the variable toric power profile described above applied to the lens. The metric used to define myopia treatment efficacy is the FOV average blur anisotropy values ​​at zero defocus across 10, 20, 30, and 40 degree FOVs. These averages are shown below:

[0083] Lens 5 (variable toric lens) 0.38 Lens 1 (single vision) -0.44 Lens 2 (EV lens) -0.16 Lens 3 (bifocal) -0.18 Lens 4 (Acuvue Abiliti) -0.11

[0084] These results are plotted in Figure 7 From this figure it is easy to see that the single vision spherical lens (lens 1) has the lowest myopia control efficacy expected. Lenses 2, 3 and 4 also each have lower myopia control efficacy values ​​than the inventive lens described herein (lens 5).

[0085] It is noteworthy that the lens with the highest myopia control efficacy is still the single vision lens (lens 5, a variable toric lens as described above), where the only difference between the two single vision lenses 5 and lens 1 (the least effective) is that lens 5 is a single vision toric lens with a variable toric power profile, while the single vision lens of lens 1 is a spherical lens. Thus, the lens of the present invention has the surprising result of achieving increased myopia control efficacy using a single vision but toric lens. No additional "myopia control" zone is required in this embodiment, thereby simplifying the design and manufacture of the lens.

[0086] It should be noted that increasing the toric power across the lens may affect image quality, particularly when present in the central vision area. If desired, the negative impact on visual quality can be further balanced with the increased efficacy. Figure 8The positioning relative to the center of the lens through which light rays enter at various FOVs (0, 10, 20, 30, 40) is illustrated for various pupil sizes (3mm, 4mm, 5mm, and 6mm). At a 0 degree FOV, paraxial rays, for example, enter the 4mm pupil through the entire 4mm. However, at a 10 degree FOV, the rays enter the 4mm pupil at a radial distance of up to 2.436mm from the center of the lens. The adverse impact on vision quality can be balanced with myopia control efficacy by utilizing variable toric power to induce positive peripheral blur outside the central vision area for a given pupil size. For a 4mm pupil size, the variable toric power can be applied outside the 4mm central optical zone to capture only peripheral rays that are completely outside the central vision area.

[0087] Fig. 9 903. The toric power profile of an exemplary lens is illustrated in which the underlying principle of the invention (using variable toric power to induce positive blur) is balanced with degradation in visual quality. In this embodiment, assuming an average pupil size of approximately 3 mm in diameter, no toric power is applied to the lens in this region, as illustrated by line 901. For portions of the lens outside the 3 mm central optical zone, the toric power may steadily increase from 3 mm to the edge of the lens, as illustrated by line 902. In one embodiment, the variable toric power of the lens is further interrupted at one or more radial zones or regions where the toric power in the lens is again reduced to zero, as illustrated by segments 902 and / or 903. It may be that for individuals with larger pupil sizes, one or more such zones may be further desired to minimize degradation in vision in regions that may still be within the pupil zone.

[0088] Although the ophthalmic lenses described in detail herein are contact lenses, the principles described and invented can be applied to any ophthalmic lens used for myopia control. For example, the optical devices described can be applied to spectacle lenses. In addition, these principles can also be applied to implantable lenses, such as intraocular lenses or phakic lenses.

[0089] Peripheral Optics Design

[0090] As described above, the results described above indicate that higher blur anisotropy values ​​are associated with better myopia control efficacy. The lenses described above introduce variable toric power to increase blur anisotropy, but blur anisotropy can also be introduced through peripheral optical elements or features as further described below. These designs can be further customized to provide a desired balance of efficacy and visual acuity.

[0091] It is well known that the central vision zone of an ophthalmic lens, which is the central viewing area of ​​the lens within the pupil diameter, is the most important for visual acuity. Optics or aberrations that disrupt central vision will have a greater impact on visual acuity than optics or aberrations outside the central vision zone. Although pupil size may vary across the population, for relatively young children and adolescents who will benefit most from myopia control lenses, pupil size typically varies between 2.5 mm and 6 mm in diameter under different lighting conditions, with 4.3 mm generally considered to be the population average for age subgroups and typical room lighting conditions.

[0092] Currently available myopia control contact lenses introduce myopic defocus areas or zones into the central viewing area of ​​the lens. While such myopic defocus areas in the central optical zone may provide better efficacy, they also degrade vision. For myopia control lenses, when defocus is introduced into the central vision zone, the design must balance this degradation in visual acuity with efficacy. The present embodiment utilizes the principles related to blur anisotropy described above to design a myopia control lens with a better balance of efficacy and visual acuity by introducing myopic defocus optics into the peripheral areas of the optical zone in a selected manner.

[0093] Return to reference Fig.10 , as an exemplary lens 1000 to which the design features described herein may be applied, the lens 1000 includes a lens center 1002 and has a shape defined by a lens peripheral edge 1003, and an optical zone 1004 surrounding the lens center and having an optical zone outer periphery 1006. As previously described, the optical zone of a lens is generally considered to be the portion of the lens through which the wearer will see to receive the intended visual correction during the normal course of wearing the lens. The optical zone may have a circular configuration defined by a radius (r) from the center of the lens. In an alternative, the optical zone may take any other suitable shape, such as may be particularly suitable for eyeglass lenses rather than contact lenses. Although the diameter may vary, the optical zone in a contact lens is generally designed to be as large as possible without compromising mechanical properties (including handling and comfort), and the diameter is generally in the range of 6 mm-10 mm. For the purpose of describing this embodiment, the optical zone is further divided into a central optical zone 1010 surrounding the center of the lens and a peripheral optical zone 1020 surrounding the central optical zone. The central optical zone 1010 is designed to have a diameter that substantially matches the wearer's pupil diameter or the typical average pupil size for a population, which is typically in the range of from 2.5 mm to 6 mm, with the population average being approximately 4.3 mm.

[0094] Fig.11The power profiles of two lens designs P1, P2 that balance myopia control treatment efficacy and visual acuity compared to known lenses that incorporate only a central optical element for myopia control effect are illustrated. The efficacy and visual acuity of these designs are evaluated assuming pupil diameters of 4 mm and 5 mm. Fig.11 It is apparent that each design comprises a continuous circumferential ring having an optical design that introduces myopic defocus to wearers of different ADD powers and at different radial locations, as indicated in the following table:

[0095] Lens P1

[0096] district 1 2 3 4 5 Radial distance(mm) 1.5-1.64 2.25-2.4 3.0-3.15 3.75-3.9 4.5-4.65 ADD power(D) 1.5 3.01 4.02 4.99 6.01

[0097] Lens P2

[0098] district 1 2 3 4 5 6 Radial distance(mm) 1.2-1.51 1.91-2.16 2.56-2.82 3.22-3.47 3.87-4.13 4.53-4.78 ADD power(D) 3.0 5.92 8.01 9.84 12.0 12.0

[0099] As used herein, the phrase ADD power reflects the degree of myopic defocus introduced relative to the base power of the lens (in diopters). For example, Fig.11 The base power of the -3D correction is reflected, and the first myopic defocus zone of lens P1 has an ADD power of about 1.5D relative to the -3D baseline correction. For embodiments P1 and P2, each concentric ring with an ADD power that causes myopic defocus produces myopic defocus as an annular focus around the optical axis, rather than as a point focus on the optical axis. Optical designs that produce myopic defocus as an annular focus around the optical axis or non-coaxial myopic annular defocus are described in detail in U.S. Patent No. 10,901,237, which is incorporated herein by reference in its entirety.

[0100] Referring first to the lens design under the 4 mm pupil diameter condition, lens design P1 has only a single circumferential zone 1101 with ADD power that introduces myopic defocus for the wearer within the central optical zone, the ADD power segment being a relatively low power of 1.5D. Outside the central optical zone (within the peripheral optical zone) is a continuous circumferential zone of increasing ADD power with increasing radial distance from the center of the lens. In the illustrated embodiment, there are 4 additional continuous rings (second ring 1102, third ring 1103, fourth ring 1104, fifth ring 1105, each ring having the following ADD power: 3.01, 4.02, 4.99 and 6.01, respectively. Under the 5 mm pupil diameter condition, the second ring 1102 will also be located within the central optical zone of the lens, and only the continuous third ring, fourth ring and fifth ring will be located in the peripheral optical zone or zone.

[0101] Referring to the second lens design P2, under the condition of 4 mm or 5 mm pupil diameter, this lens design has at least a first 1110 myopic defocus ring located in the central optical zone, and at least a first 1113 myopic defocus ring and a second 1114 myopic defocus ring located in the peripheral optical zone. This embodiment may also include a second myopic defocus ring 1111 located at least partially in the central optical zone, and may also include a third 1114 myopic defocus ring and a fourth 1115 myopic defocus ring located in the peripheral optical zone.

[0102] The peripheral FOV model described above applied to the P1 and P2 lens designs generates the blur anisotropy values ​​shown in Figures 12a and 12b, respectively, for the 4 mm pupil size condition, and the blur anisotropy values ​​shown in Figures 13a and 13b, respectively, for the 5 mm pupil size condition (in each figure, reference numerals 1200, 1210, 1220, 1230, and 1240 correspond to 0, 10, 20, 30, and 40 degree FOVs, respectively). For the 4 mm pupil size condition, the size and position of the focal line at the retina are reflected in the following table:

[0103] Degree FOV P1 value P2 value 0 0 0 10 -0.0454 -0.1291 20 -0.2949 -0.1612 30 -0.1592 -0.1661 40 -0.0027 -0.18978

[0104] The average blur anisotropy value for the P1 lens was -0.1255 and the average blur anisotropy value for the P2 lens was -0.1615. The average blur anisotropy values ​​for the known lenses as described above in conjunction with the toric design (for a 4 mm pupil size) are reproduced again below. The lenses with non-coaxial annular focus are Lens 4 and Lens 6, which is the same as Lens 4 but does not have a small, high ADD power annulus at the exact center of the lens that converges on an on-axis focus in front of the retina.

[0105] Lens 5 (Variable ToricLens) 0.38 Lens 1 (single vision) -0.44 Lens 6 -0.16 Lens 3 (bifocal) -0.18 Lens 4 (Acuvue Abiliti) -0.11

[0106] It can be easily seen that the P1 lens with an average blur anisotropy of -0.1255 has very similar myopia control efficacy to lens 4 (-0.11), and has better efficacy than lens 6 (-0.16). The P2 lens efficacy is comparable to lens 6, but slightly worse than lenses 5, 3, and 4.

[0107] For myopia control lenses, it is desirable to provide the best possible balance between efficacy and visual acuity. Based on visual acuity modeling assuming a 4 mm diameter pupil condition, projected visual acuity has been established for lenses P1 and P2 and the existing lenses described above with the highest myopia control efficacy (Lens 4 and Lens 6), and are set forth in the following table:

[0108] Lens design VA(-10logMAR) Lens 4 -2.4 Lens 6 -0.9 Lens 5 0.04 P1 0 P2 -1.0

[0109] Lens P1 has improved visual acuity over both Lens 4 and Lens 6, while Lens P2 exhibits visual acuity superior to Lens 4 and substantially similar to Lens 6. For the lenses discussed above, the following table shows efficacy and visual acuity values ​​for each lens for ease of reference.

[0110] lens effect VA Lens 4 -0.11 -2.4 Lens 6 -0.16 -0.9 Lens 5 0.38 0.04 P1 -0.1255 0 P2 -0.1615 -1.0

[0111] In summary, lens P1 has an efficacy level close to that of lens 4, but has significantly improved visual acuity (almost 2.5 lines of improvement). Lens P1 also has an efficacy that is better than lens 6 and almost a full line improvement in visual acuity. Lens P2 has slightly worse efficacy than lens 4, but has almost 1.5 lines of improvement in visual acuity, and has substantially similar efficacy and visual acuity to lens 6.

[0112] For the 5 mm pupil size condition, the blur anisotropy values ​​are shown in Figures 13a and 13b. For comparison purposes, the blur anisotropy values ​​for lenses 6 and 4 described above, assuming a 5 mm pupil size condition, are shown in Figures 14a and 14b, respectively. For the 5 mm pupil size condition, the size and position of the focal line at the retina for P1, P2 and lens 4 are reflected in the table below.

[0113]

[0114]

[0115] According to the above table, the average blur anisotropy of lens P1 is -0.0812, the average blur anisotropy of lens P2 is -0.0931, and the average blur anisotropy of lens 4 is -0.1177. Therefore, both P1 and P2 show higher efficacy than lens 4.

[0116] Based on visual acuity modeling assuming a 5 mm diameter pupil condition, projected visual acuity has been established for lenses P1 and P2 and the existing lenses described above with the highest myopia control efficacy (Lens 4 and Lens 6), and are set forth in the following table:

[0117] Lens design VA(-10logMAR) Lens 4 -2.12 Lens 6 -0.76 Lens 5 -0.28 P1 -0.21 P2 -1.21

[0118] Lens P1 similarly has an improved visual acuity over both Lens 2 and Lens 4, while Lens P2 has an improved visual acuity of Lens 4 and has a visual acuity about half a line worse than Lens P1. For the lenses discussed above, the table below shows the efficacy and visual acuity values ​​for each lens for ease of reference.

[0119] lens effect VA Lens 4 -0.1177 -2.12 Lens 6 -0.1327 -0.76 Lens 5 0.38 -0.28 P1 0.0264 -0.21 P2 -0.0649 -1.21

[0120] In summary, lens P1 has improved efficacy over both lens 6 and lens 4, as well as significantly improved visual acuity (almost 2 lines) over lens 4 and visual acuity substantially similar to lens 6. Lens P2 also has better efficacy than both lens 6 and lens 4, with improved visual acuity (almost 1 line) over lens 4 and visual acuity that is approximately 0.5 lines worse than lens 6.

[0121] The embodiments described above are directed to the purpose of increasing positive blur anisotropy, which assumes a horizontal peripheral field of view. Although the foregoing relates to embodiments of the present invention, other and further embodiments of the present invention may be devised without departing from the basic scope of the invention, which is limited only by the scope of the following claims. For example, the present invention contemplates that any feature shown in any embodiment described herein may be combined with any feature shown in any other embodiment described herein or incorporated herein by reference and still fall within the scope of the present invention.

Claims

1. An ophthalmic lens comprising: The center of the lens and the shape defined by the peripheral edge of the lens; an optic zone surrounding the lens center and having an optic zone outer perimeter, the optic zone having a power selected to correct a myopic condition of a user of the lens; and wherein the lens has a toric power at the center of the lens that is less than the toric power at the outer periphery of the optical zone and has a variable toric power that increases radially across at least a portion of the lens to at least the outer periphery of the optical zone, The variable toric optical power has a predetermined optical power distribution, and the predetermined optical power distribution causes an emmetropic field average blur anisotropy of the user at or in front of the retinal plane of the user.

2. The ophthalmic lens of claim 1, wherein the field average blur anisotropy is positive at the retinal plane across a field of view of 0 to 40 degrees.

3. The ophthalmic lens of claim 1, wherein the variable toric power increases continuously from the center of the lens to the outer periphery of the optical zone.

4. The ophthalmic lens of claim 1, wherein the variable toric power is given by the equation: Toric Power = 0.0642(r) 3 –0.1063(r) 2 –0.018(r) definition, where r is equal to the radius from the center of the lens.

5. An ophthalmic lens according to claim 1, wherein the lens further comprises a lens center zone, the lens center zone being centered on the lens center within the optical zone and having a lens center zone diameter, wherein the lens has zero toric power in the lens center zone, and the variable toric power extends radially outward from the lens center zone to an outer periphery of the optical zone.

6. The ophthalmic lens of claim 5, wherein the lens central zone diameter is designed to match an average pupil diameter of a predetermined population.

7. The ophthalmic lens of claim 5, wherein the lens central region diameter is between 3 mm and 5 mm.

8. The ophthalmic lens of claim 5, wherein the variable toric power profile between the lens central region and the outer periphery of the optical zone is interrupted by at least one radial segment across which the toric power is zero.

9. The ophthalmic lens of claim 5, wherein the variable toric power profile between a central region of the lens and an outer periphery of the optical zone is interrupted by a first radial segment and a second radial segment, the toric power being zero across the first radial segment and the second radial segment.

10. The ophthalmic lens of claim 1, wherein the myopia control efficacy of the lens is greater than a comparable spherical single vision lens of the same refractive power but without the variable toric power profile.

11. The ophthalmic lens of claim 1 , wherein the lens is a contact lens.

12. The ophthalmic lens of claim 1, wherein the lens is a spectacle lens.

13. The ophthalmic lens of claim 1, wherein the lens is an intraocular lens or a phakic lens.

14. The ophthalmic lens of claim 1, wherein the variable toric power profile is on the front surface of the lens.

15. The ophthalmic lens of claim 1, wherein the variable toric power profile is on a posterior surface of the lens.

16. A method for designing an ophthalmic lens for human use, comprising: creating a lens design for an ophthalmic lens having a lens center and a shape defined by an outer edge of the lens, and an optical zone surrounding the lens center and having an optical zone outer periphery, wherein a refractive power of the optical zone is selected to correct myopic vision of the person; A variable toric power profile across at least a portion of the optical zone of the lens is applied to the lens design, wherein the variable toric power profile has toric power that increases radially from a center of the lens and is configured to induce an emmetropia average blur anisotropy in the person at or in front of a retinal plane of the person.

17. The method of claim 16, wherein the field-averaged blur anisotropy is positive at the retinal plane across a 0 to 40 degree field of view.

18. The method of claim 17, wherein the variable toric power increases continuously from the center of the lens to the outer periphery of the optical zone.

19. The method of claim 17, wherein the variable toric power is given by the equation: Toric Power = 0.0642(r) 3 –0.1063(r) 2 –0.018(r) definition, where r is equal to the radius from the center of the lens.

20. The method of claim 17, wherein the ophthalmic lens design further comprises a lens center zone within the optical zone and centered about the lens center, and wherein the lens has zero toric power within the lens center zone.

21. The method of claim 20, wherein the diameter of the central region of the lens is between 3 mm and 5 mm.

22. The method of claim 17 wherein the variable toric power profile between the lens central region and the outer periphery of the optic zone is interrupted by at least one radial segment across which the toric power is zero.

23. The method of claim 17, wherein the myopia control efficacy of the lens is greater than a comparable spherical single vision lens of the same optical power but without the variable toric power profile.

24. The method of claim 17, wherein the lens is a contact lens.

25. The method of claim 17, wherein the lens is a spectacle lens.

26. The method of claim 17, wherein the lens is an intraocular lens or a phakic lens.

27. The ophthalmic lens of claim 17, wherein the variable toric power profile is on the front surface of the lens.

28. The ophthalmic lens of claim 17, wherein the variable toric power profile is on the posterior surface of the lens.

29. A contact lens for slowing the progression of myopia in a wearer, comprising: a single vision lens having a lens center and a shape defined by a lens peripheral edge, an optical zone surrounding the lens center within the lens peripheral edge and defined by an optical zone outer periphery, the optical zone having a predetermined refractive power selected to correct a myopic condition of the wearer; and A variable toric power profile is applied to at least a portion of the optical zone, the toric power profile being configured to induce an emmetropic field-averaged blur anisotropy for the wearer at or in front of a retinal plane of the wearer.

30. The contact lens of claim 29 wherein the field average blur anisotropy is positive at the retinal plane spanning a field of view of 0 to 40 degrees.

31. The contact lens of claim 29 wherein the toric power profile is a variable toric power profile that increases radially from the center of the lens.

32. The contact lens of claim 31 wherein the variable toric power increases continuously from the center of the lens to at least the outer periphery of the optic zone.

33. The contact lens of claim 31 wherein the variable toric power is given by the equation: Toric Power = 0.0642(r) 3 –0.1063(r) 2 –0.018(r) definition, where r is equal to the radius from the center of the lens.

34. A contact lens according to claim 31, wherein the lens further includes a lens central zone, the lens central zone is centered on the lens center and within the optical zone and has a lens central diameter, wherein the lens has zero toric optical power in the lens central zone, and the variable toric optical power extends radially outward from the lens central zone to at least the outer periphery of the optical zone.

35. The contact lens of claim 34, wherein the lens center diameter substantially matches an average pupil diameter of a predetermined population.

36. The contact lens of claim 34, wherein the lens center diameter is between 3 mm and 5 mm.

37. The contact lens of claim 34 wherein the variable toric power profile between the lens central region and the outer periphery of the optic zone is interrupted by at least one radial segment across which the toric power is zero.

38. The contact lens of claim 34 wherein the variable toric power profile between a central region of the lens and an outer periphery of the optic zone is interrupted by a first radial segment and a second radial segment, the toric power being zero across the first and second radial segments.

39. The contact lens of claim 31 wherein the myopia control efficacy of the lens is greater than a comparable spherical single vision lens of the same refractive power but without the variable toric power profile.

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