Ophthalmic lenses for myopia control

Abstract

An ophthalmic lens and a system for designing the lens. The lens includes a shape defined by a lens center and a lens outer periphery. An optical zone surrounds the lens center and has an optical zone periphery having a refractive power selected to correct a user's myopic condition. The lens has a toric power at the lens center that is less than the toric power at the optical zone periphery and has a variable toric power that increases radially over at least a portion of the lens to at least the optical zone periphery. The variable toric power has a predetermined power profile that induces a positive visual field average blur anisotropy for the user at or in front of the user's retinal plane.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 434,819, filed December 22, 2022, and U.S. Provisional Patent Application No. 63 / 548,432, filed November 14, 2023.

[0002] FIELD OF THE INVENTION This application relates to ophthalmic lenses designed to arrest or reduce the progression of myopia in a patient. More specifically, this application is directed to lens designs and methods for lens designs that induce a predetermined peripheral blur orientation or otherwise increase the average peripheral blur anisotropy value at the retinal plane. [Background technology]

[0003] Common conditions leading to decreased vision include myopia and hyperopia, for which corrective lenses in the form of glasses or hard or soft contact lenses are prescribed. These conditions are generally explained as an imbalance between the length of the eye and the focal point of the eye's optical components. A myopic eye focuses light from distant objects in front of the retinal plane, while a hyperopic eye focuses light from distant objects behind the retinal plane. Myopia typically occurs when the axial length of the eye is longer than the focal length of the eye's optical components, i.e., the eye becomes too long. Hyperopia typically occurs when the axial length of the eye is too short compared to the focal length of the eye's optical components.

[0004] Myopia has a high prevalence in many parts of the world. The greatest concern about this condition is its potential progression to high myopia, e.g., greater than 5 or 6 diopters, which dramatically impacts the ability to function without visual 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), which may be a leading cause of permanent blindness worldwide. MMD is associated with refractive error (RE) to such an extent that there is no clear distinction between pathological and physiological myopia, and no "safe" level of myopia exists.

[0005] Corrective lenses are used to change the gross focus of the eye to present a clearer image at the retinal surface by shifting the focal point from in front of the retinal surface to correct myopia or from behind the retinal surface to correct hyperopia, respectively. However, corrective approaches to the above conditions are merely prosthetic, i.e., they aim to address the symptoms rather than address the cause of the condition.

[0006] Most eyes do not have simple myopia or simple hyperopia, but also myopic astigmatism or hyperopic astigmatism. Astigmatic error of focus causes the image of a point light source to form 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 simple astigmatism, and hyperopia and hyperopic simple astigmatism, respectively.

[0007] Emmetropia describes a state of clear vision in which objects at infinity are in relatively sharp focus without the need for optical correction and with the lens relaxed. In a normal, or emmetropic, adult eye, light from both distant and near objects passing through the central, or paraaxial, area of ​​the aperture, or pupil, is focused by the crystalline lens inside the eye near the retinal plane where an inverted image is perceived. However, most emmetropic eyes are observed to exhibit positive longitudinal spherical aberration, meaning that when the eye focuses at infinity, light rays passing through the aperture or pupil at its periphery focus in front of the retinal plane. As used herein, the measure D is diopter power, defined as the reciprocal of the focal length of a lens or optical system in meters.

[0008] The spherical aberration of a normal eye is not constant: for example, accommodation (changes in the refractive power of the eye induced primarily through modifications to the crystalline lens) causes the spherical aberration to change from positive to negative.

[0009] As noted, myopia is typically caused by excessive axial elongation, or elongation, of the eye. It is now generally accepted that axial elongation of the eye can be affected by the focus and quality of the retinal image, and that altering the retinal image can result in consistent and predictable changes in ocular elongation.

[0010] Known approaches that attempt to eliminate or reduce axial elongation of the eye, particularly in children, include the application of ophthalmic lenses that intentionally introduce myopic defocus into the visual field. Myopic defocus introduces a "stop" stimulus to the eye, resulting in limited ocular elongation. This is first observed as a thickening of the choroid. Animal studies have demonstrated that changes in ocular elongation in response to retinal image defocus are largely mediated through local retinal mechanisms, as changes in ocular length still occur when the optic nerve is damaged, and the appearance of defocus in a local retinal region has been shown to alter ocular elongation localized to that specific retinal region.

[0011] Ophthalmic lenses with concentric annular designs have been shown to slow the progression of myopia. These include the Acuvue® Bifocal lens by Johnson & Johnson Vision Care, Inc. and the MiSight® contact lens by CooperVision, Inc. These lenses have certain annular zones that contain optics that correct myopia, while others introduce myopic defocus. Light from a distant object along the optical axis that passes through a given annulus essentially arrives at a single focus on the optical axis, landing on and in front of the retina for the myopia-correcting annulus and myopic defocus annulus, respectively.

[0012] U.S. Patent No. 10,901,237, incorporated herein by reference in its entirety, describes various other lens designs for myopia control, with particular application in soft contact lenses. These lenses also have concentric annular designs, in which certain annular zones contain optics that focus on the retina. For patients who require myopic correction, these annular zones may contain optics that redirect the focus onto the retina. For patients who do not require myopic correction, these annular zones may not provide optical correction. Non-central myopic defocus annular zones contain optics that focus light passing therethrough in front of the retina, but rather than a single point focus on the optical axis, the light forms a non-coaxial ring focus. In some disclosed embodiments, the central portion of the lens contains an add power that is along the optical axis but induces myopic defocus.

[0013] Lens designs such as these tend to emphasize on-axis optics from light rays emanating from objects along the optical axis, more specifically, generating a focal point in the central region. Furthermore, these lens designs focus on design principles based on central vision, incorporating optical elements within the central vision region to generate myopic defocus. In addition to central vision, peripheral refractive error can have a substantial impact on central refractive development, and it has been shown that myopic defocus in the near periphery can slow axial elongation. See Smith, Vision Reg., September 2009;49(19):2386-2392.

[0014] Additional aberrations that may further contribute to the progression of myopia occur in peripheral vision. In astigmatic eyes, the refraction of the eye is not spherical or rotationally uniform; rather, due to the oval or "football" shape of the eye, the refractive power along one meridian is different from the refractive power along the vertical meridian, such that the focal lines along the two meridians are at different distances. Regular astigmatism is typically classified as "straight," "inverted," or "oblique." For individuals with "straight" astigmatism (the most common), the vertical meridian has the strongest power or steepest curvature compared to the horizontal meridian. Oblique astigmatism occurs when the strongest power or steepest curvature is not on the vertical or horizontal meridian.

[0015] Similar to the potential for astigmatism in central vision, peripheral astigmatism is well known to be produced by light rays striking the refractive surfaces of the cornea and lens at oblique incidence. This astigmatism and other wavefront aberrations cause optical blur in the peripheral retina that is highly anisotropic. Blur anisotropy is herein defined 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 (temple-nasal) meridian, i.e., blur anisotropy = log [(area)] 垂直 / (area) 水平]. As a result, blur anisotropy is negative when an image (or point spread function) has primarily vertically oriented blur and 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 as it moves around the retina, a principle known as the meridional effect.

[0016] An exemplary illustration of peripheral blur anisotropy is shown in Figure 2, where the blur at the retinal plane has an asymmetric pattern such that the length of the blur pattern in one direction (i.e., along the y-axis) is longer than in the vertical direction. In Figure 2, the optical resolution is finer along the x-axis than along the y-axis. As noted above, the orientation of the peripheral blur varies around the periphery of the retina.

[0017] Peripheral vision can also be exploited to induce myopia suppression. In a recent publication titled "Eccentricity-Dependent Effects of Simultaneous Competing Defocus on Emmetropization in Infant Rhesus Monkeys" (Vision Research 177 (2020) 32-40), the authors demonstrated that myopic defocus approximately 20° off the fovea can substantially affect central refractive development in primates. Another publication hypothesized that neural orientation sensitivity coincides with habitual blur orientation, and that blur orientation may trigger eye elongation. Zhelenznyak et al. (2016), Optical and Neural Ansiotropy in Peripheral Vision, Journal of Vision, 16(5):1, 1-11.

[0018] More recently, Ji et al. utilized modeling techniques to evaluate certain bifocal and multifocal contact lenses, adapted to incorporate add power to induce myopic defocus, compared with monofocal lenses to assess the lens's effect on peripheral vision at various degrees of decentration. 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 showed that the former two lenses also demonstrated reduced anisotropy of peripheral blur and increased depth of focus when compared with monovision lenses. From this, the authors hypothesized that the mechanism underlying myopia control with bifocal and multifocal lenses is reduced anisotropy of peripheral blur coupled with increased depth of focus.

[0019] Yoon, U.S. Patent Publication No. 2022 / 0252901 ("Yoon"), describes an optical lens for myopia prevention that intentionally introduces peripheral aberrations with the goal of manipulating peripheral blur to make it more radially symmetric. In other words, based on the previous hypothesis in the Ji paper that it is desirable to reduce the anisotropy of peripheral optical blur, the present application describes the goal of intentionally minimizing the anisotropy in the peripheral region to the point where it is radially symmetric, as shown, for example, in FIG. 1 . In other words, the lens described in Yoon prefers to have 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. Conversely, the lenses described herein prefer both the tangential and sagittal focal lines to be in front of the retina or to have blur anisotropy values ​​adjusted toward the positive direction. Summary of the Invention [Problem to be solved by the invention]

[0020] The inventors herein have discovered that, contrary to the teachings of Yoon and Ji, lenses designed with high blur anisotropy in an orientation opposite to that seen in peripheral hyperopia exhibit better myopia control treatment efficacy. Leveraging these findings, lens designs incorporating peripheral optics that increase the average peripheral blur anisotropy value (toward the positive direction) will also improve efficacy. The present disclosure is directed to such lens designs and methods for designing such lenses. [Means for solving the problem]

[0021] An ophthalmic lens is provided having a shape defined by a lens center and a lens peripheral edge. An optical zone surrounds the lens center, has an optical zone periphery, and has a refractive power selected to correct a myopic condition of a user of the lens. The lens has a toric power at the lens center that is less than the toric power at the optical zone periphery and has a variable toric power that increases radially over at least a portion of the lens to at least the optical zone periphery. The variable toric power has a predetermined power profile that induces a positive visual field average blur anisotropy for the user at or in front of the user's retinal plane.

[0022] The visual field average blur anisotropy may be positive at the retinal plane over a visual field of 0 to 40 degrees, and the variable toric power may increase continuously from the lens center to the optical zone periphery.

[0023] In one embodiment, the variable toric power is calculated using the formula: Toric Power=0.0642(r) 3 -0.1063(r) 2 It is defined by −0.018(r), where r is equal to the radius from the center of the lens.

[0024] The lens may further include a lens central region centered within the optical zone at a lens center and having a lens central region diameter. The lens center may have zero toric power at the lens central region, and the variable toric power may extend radially outward from the lens central region to the optical zone periphery. The lens central region diameter may be designed to match the average pupil diameter of a predetermined population and may be between 3 mm and 5 mm.

[0025] In yet another embodiment, the variable toric power profile between the lens central region and the optical zone periphery can be interrupted by at least one radial segment with zero toric power and by first and second radial segments with zero toric power.

[0026] The lens may have greater myopia-suppressing efficacy than an equivalent spherical single vision lens of the same refractive power that does not have a variable toric power profile.

[0027] The lens can be a contact lens, a spectacle lens, an intraocular lens, or a phakic lens.

[0028] The variable toric power profile can be on the anterior surface of the lens or on the posterior surface of the lens.

[0029] Also provided is a method for designing an ophthalmic lens, the method comprising creating a lens design having a shape defined by a lens center and a lens outer edge, and an optical zone surrounding the lens center and having an optical zone periphery. The refractive power of the optical zone is selected to correct the person's myopic vision. The method further comprises applying to the lens design a variable toric power profile across at least a portion of the optical zone of the lens, the variable toric power profile having a toric power that increases radially from the lens center and that is configured to induce a positive visual field average blur anisotropy in the person at or in front of the person's retinal plane.

[0030] Field-averaged blur anisotropy can be positive at the retinal plane over a field of view of 0 to 40 degrees.

[0031] According to one embodiment, the variable toric power increases continuously from the center of the lens to the periphery of the optical zone. The variable toric power is calculated by the formula: Toric Power=0.0642(r) 3 -0.1063(r) 2 It can be defined by −0.018(r), where r is equal to the radius from the center of the lens.

[0032] In yet another embodiment, the lens design further includes a central lens region within the optic zone and centered about the lens center, the lens having zero toric power within the central lens region. The diameter of the central lens region can be between 3 mm and 5 mm.

[0033] 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 of zero toric power.

[0034] The lens may have greater myopia control efficacy than an equivalent spherical single vision lens of the same power but without a variable toric power profile.

[0035] The lens can be a contact lens, a spectacle lens, an intraocular lens, or a phakic lens.

[0036] The variable toric power profile can be on the anterior surface of the lens or on the posterior surface of the lens.

[0037] Also provided is a contact lens for slowing the progression of myopia in a wearer, the contact lens including: a single vision lens having an optical zone having a predetermined refractive power selected to correct the wearer's myopic condition, the optical zone having a shape defined by a lens center and a lens periphery, the optical zone surrounding the lens center within the lens periphery and defined by an optical zone periphery, the optical zone having a predetermined refractive power selected to correct the wearer's myopic condition; and a variable toric power profile applied to at least a portion of the optical zone, the toric power profile configured to induce a positive visual field average blur anisotropy for the wearer at or in front of the plane of the wearer's retina.

[0038] Field-averaged blur anisotropy can be positive at the retinal plane over a field of view of 0 to 40 degrees.

[0039] The toric power profile may be a variable toric power profile that increases radially from the lens center and may also increase continuously from the lens center to at least the optic zone periphery. In one embodiment, the variable toric power is calculated according to the formula: Toric Power=0.0642(r) 3 -0.1063(r) 2 It is defined by −0.018(r), where r is equal to the radius from the center of the lens.

[0040] The lens may further include a lens central region centered about the lens center and within the optical zone, the lens having a lens central diameter, the lens having zero toric power in the lens central region, and the variable toric power extending radially outward from the lens central region to at least the outer periphery of the optical zone. The lens central diameter may substantially correspond to the average pupil diameter of a predetermined population, and may be between 3 and 5 mm.

[0041] In one embodiment, the variable toric power profile between the lens central region and the optical zone periphery is interrupted by at least one radial segment with zero toric power and may be further interrupted by first and second radial segments with zero toric power.

[0042] The lens may have greater myopia control efficacy than an equivalent spherical single vision lens of the same refractive power but without a variable toric power profile. [Brief explanation of the drawings]

[0043] 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. [Figure 1] The illustrated pattern is generated by ray tracing through a model eye, with each cross representing the intersection of a ray with the retina, illustrating an anisotropic peripheral blur pattern where light rays emanating from a point source are uniformly distributed across the pupil. [Figure 2] The pattern is generated by ray tracing through a model eye, with each cross representing the intersection of a ray with the retina, illustrating an anisotropic peripheral blur pattern where the rays originate from a point source and are uniformly distributed across the pupil. [Figure 3] 1 illustrates an eye model for simulating central and peripheral vision. [Figure 4A] 1 illustrates blur anisotropy values ​​for various lenses. [Figure 4B] 1 illustrates blur anisotropy values ​​for various lenses. [Figure 4C] 1 illustrates blur anisotropy values ​​for various lenses. [Figure 4D] 1 illustrates blur anisotropy values ​​for various lenses. [Figure 5] 1 illustrates a toric power profile for a lens according to the present invention. [Figure 6] 6 illustrates blur anisotropy values ​​for the lens of FIG. 5. [Figure 7] 6 illustrates myopia control efficacy values ​​for the lenses of FIGS. 4 and 5. [Figure 8] 1 illustrates the lower peripheral ray position relative to the center of the eye for various pupil sizes. [Figure 9]1 illustrates a toric power profile for an alternative lens according to the present invention. [Figure 10] 1 illustrates an exemplary lens to which the present invention can be applied. [Figure 11] 1 illustrates a power profile for a lens according to the present disclosure incorporating peripheral optical features. [Figure 12A] 12 illustrates blur anisotropy values ​​for the embodiment of FIG. 11 under 4 mm pupil size conditions. [Figure 12B] 12 illustrates blur anisotropy values ​​for the embodiment of FIG. 11 under 4 mm pupil size conditions. [Figure 13A] 12 illustrates blur anisotropy values ​​for the embodiment of FIG. 11 under 5 mm pupil size conditions. [Figure 13B] 12 illustrates blur anisotropy values ​​for the embodiment of FIG. 11 under 5 mm pupil size conditions. [Figure 14A] 4 illustrates blur anisotropy values ​​for the lenses of FIGS. 4b and 4d under 5 mm pupil size conditions. [Figure 14B] 4 illustrates blur anisotropy values ​​for the lenses of FIGS. 4b and 4d under 5 mm pupil size conditions. DETAILED DESCRIPTION OF THE INVENTION

[0044] The present disclosure relates to ophthalmic lens designs and methods for designing ophthalmic lenses that induce directional peripheral blur to enhance myopia control efficacy. The present disclosure also relates to ophthalmic lens designs and methods for designing lenses that introduce optical elements or features in the peripheral optical zone that increase the average peripheral blur anisotropy value, thereby increasing myopia control efficacy or otherwise providing a better balance of efficacy and visual acuity. Ophthalmic lenses to which the present disclosure applies include, but are not limited to, contact lenses, spectacle lenses, and implantable ophthalmic lenses, such as intraocular lenses and phakic lenses, that are placed in the eye of a person or wearer.

[0045] Variable Toric Design As mentioned above, typical human vision provides a focused image in the central vision region and progressively anisotropic blurred images toward the periphery of the eye. For individuals requiring correction (nearsightedness or farsightedness), ophthalmic lenses typically focus on correcting central vision, which is within approximately 10 degrees of the line of sight. Figure 3 illustrates an eye model showing a field of view (FOV) ranging from 0 to 40 degrees. The eye model used herein to evaluate peripheral blur is similar to the model described by Navarro et al. in the publication J. Opt. Soc. Am. A 16, 1881-1891 (1999), which is incorporated herein by reference. The model was modified to include only minor variations in the corneal and lens surfaces of the model based on the use of actual biometric data. The eye model was constructed to represent the optical and mechanical properties of the averaged eye, including wavefront aberrations, anterior corneal curvature, etc., of the general population. The eye model was also used to simulate visual impairment (scattering) as described by Chen in the publication "Evaluating the Effects of Scattering on Retinal Image Quality," Proc. SPIE11941, Ophthalmic Technologies XXXII, 119410B (March 4, 2022).

[0046] Those skilled in the art know that a typical eye experiences increased blur with increasing peripheral FOV angle. Furthermore, the meridional effect is known to cause the orientation of the blur pattern to change peripherally. Furthermore, there is better performance for higher FOV angles when viewing horizontal gratings than vertical gratings, when compared to central vision viewing a substantially similar image along the horizontal meridian.

[0047] Also, as mentioned above, Ji hypothesized that eliminating or minimizing peripheral blur orientation (producing an isotropic blur pattern) would improve the myopia-suppressing efficacy of the lens. Contrary to this teaching, the inventors herein have discovered that inducing an anisotropic blur pattern produced by myopic astigmatism is desirable and more effective.

[0048] To quantitatively evaluate peripheral image blur orientation, several myopia control lenses, including the Acuvue® Abiliti™ lens from Johnson & Johnson Vision Care, Inc., were evaluated using the model described above under 4 mm pupil conditions. Figures 4a-4b illustrate the blur anisotropy of the evaluated lenses, where a monofocal lens ("Lens 1") is shown in Figure 4a, an Acuvue® Abiliti™ lens ("Lens 4") is shown in Figure 4d, a first test lens similar to the Acuvue® Abiliti™ lens but without a high-add central treatment zone is shown in Figure 4b ("Lens 2"), and a second bifocal test lens with dual coaxial foci is shown in Figure 4c ("Lens 3"). Blur anisotropy is negative when the image has a vertical orientation and positive when the image has a horizontal orientation. Within each figure, blur anisotropy at FOVs of 0, 10, 20, 30, and 40 degrees is indicated by reference numerals 400, 410, 420, 430, and 440, respectively. For each graph, the vertical line at x=0 represents the retinal plane, i.e., zero focal blur, and the horizontal axis indicates focal blur either in front of (positive) or behind (negative) the retina. As shown in these figures, for all lenses, blur anisotropy is negative at the retinal plane for all non-zero FOV degrees, except for the 10-degree FOV for the lens of FIG. 4d.

[0049] As shown in Figures 4a-4d, in the peripheral field, blur anisotropy exhibits both maxima and minima both in front of and behind the retina, corresponding to the astigmatic focal line. For the monofocal lens shown in Figure 4a, the magnitude and location of the focal line at the retina vary significantly, being -0.13, -0.35, -0.41, and -0.89 for 10, 20, 30, and 40 degrees of field of view, respectively. The FOV-averaged blur orientation value at the retinal plane is -0.44 (calculated excluding foveal vision at 0 degrees of field of view). The FOV-averaged blur anisotropy values ​​of the myopia-suppressing lenses in 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 in Figures 4b and 4d under a 5mm pupil size condition.

[0050] As demonstrated in clinical studies using these same lenses, increasingly positive FOV average blur anisotropy values ​​correlate with increasing myopia-control efficacy. 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 visual acuity) corresponds to Lens 2. This clinical trial was a multinational, prospective, randomized, controlled, double-blind, stratified, myopia control clinical trial (NCT03408444). The purpose of the study was to compare the efficacy and visual acuity of the four lenses. A total of 185 patients completed the study. All study participants were 7 to 12 years old and each had a spherical error ranging from -0.75D to -4.50D, astigmatism <= 1.00D, and anisometropia < 1.5D. There were no statistically significant differences in baseline characteristics among study participants, as shown in the table below.

[0051] [Table 1]

[0052] Lens effectiveness was determined by both measuring axial length (using the LENSTAR System) and assessing cycloplegic equivalent spherical autorefraction (SECAR) using a Grand Seiko WAM-5500 device; five repeated measurements were performed, each representing the average of three consecutive readings.

[0053] The study concluded that all three study lenses were effective in slowing the axial elongation of the eye compared to the SV. The efficacy results from this study are shown below:

[0054] TIFF2025539965000003.tif57135

[0055] In Figure 2A above, the top line represents the single vision (SV) lens, the next line represents the bifocal (DF) lens, then the EV, and the bottom line represents the lens EE. In Figure 2B above, the top line is the lens EE, then the lens DF, then the lens EV, and the bottom line is the lens SV.

[0056] These results indicate that higher blur anisotropy values ​​correlate with better myopia control efficacy. The lenses described herein are designed to produce positive FOV average blur anisotropy values, as opposed to the negative values ​​demonstrated in known myopia control (and spherical) lens designs, and the near-zero blur anisotropy targeted in the lenses described in the Yoon patent publication.

[0057] At its most general level, the present lenses can achieve improved myopia control efficacy in single vision lenses by incorporating only variable toric power into the lens. Here, the term toric is not used in the more universally applied sense used in optical devices for the correction of central refractive astigmatism. In one embodiment, variable toricity is described in the spatial domain by increasing the amount of distance away from the center of the optical device through the introduction of aspheric surfaces, which can produce a change to the oblique astigmatism typically generated in such devices. In another embodiment, variable toricity is described in the angular / FOV domain by increasing the amount of distance away from the central FOV through the introduction of aspheric surfaces, which can produce a change to the oblique astigmatism typically generated in such devices. It is the toric power profile itself that introduces the myopia control effect. In this way, the present lenses achieve a level of myopia control efficacy with a lens design that is less complex than currently available myopia control lenses.

[0058] One lens design according to the present invention includes different curvatures along the sagittal and tangential directions to produce variable toric power throughout the lens. For clarity, "variable toric power," as used herein with respect to an ophthalmic lens, refers to a lens having toric power that varies radially from the lens center outward across the optic zone or at least a portion of the optic 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 subject to discontinuities at certain radial locations, as further described below.

[0059] The principles described herein can be readily applied to various types of ophthalmic lenses. In the case of contact lenses, an exemplary lens is shown in FIG. 10. Contact lens 1000 includes an optical zone 1004 that surrounds the lens center and has an optical zone periphery 1006, and the optical zone 1004 surrounds the lens center and has an optical zone periphery 1006. The optical zone of a lens is typically considered the portion of the lens that a wearer sees during the normal course of wearing the lens to receive the intended vision correction. For example, for a myopic patient, the optical zone may have a -3D power to correct the patient's myopic vision. The optical zone may have a circular configuration defined by a radius (r) from the lens center. Alternatively, the optical zone may have any other suitable shape, such as may be particularly applicable to spectacle lenses rather than contact lenses. The optical zone may be a monofocal optical zone (having a single refractive power) or may include other regions within the optical zone, such as specific myopia treatment regions, as further described below. Although diameter can vary, the optic zone in a contact lens is typically designed to be as large as possible without compromising mechanical properties including handling and comfort, and typically falls within the range of 6-10 mm in diameter.

[0060] In the case of a myopia control lens, the optical zone may optionally further include one or more additional myopia treatment regions 1010, such as a high ADD power zone at the very center of the lens. While not necessary for myopia control, as explained further below, such a region may increase the effectiveness of the lens because the relative ADD power induces myopic blur so that the focus falls in front of the retina, providing a stimulus to move the retina toward the myopic defocus point, as will be readily understood by those skilled in the art. This, in turn, provides a counter signal to further distraction of the eye or myopic progression.

[0061] Although the above embodiments include a high ADD power region at the center of the lens, any suitable configuration or location of one or more additional myopia treatment regions can be used, whether centrally located, on-axis (where the myopic focus is on the optical axis but in front of the retina), or off-axis (where the myopic focus is in front of the retina but not coincident with the optical axis).

[0062] In one embodiment, the contact lens has an aspheric posterior curvature with a radius of 7.85 and a conic constant of -0.26. The anterior surface has a specially designed biconic structure so that the toric power steadily increases from zero at the center of the lens radially outward to the edge of the lens, as shown in Figure 5. Importantly, in this exemplary embodiment, the toric power of the lens increases in a predetermined manner so that the blur anisotropy at or in front of the retina becomes positive. The variable toric power profile illustrated in Figure 5 is calculated using the formula Toric Power = 0.0642(r) 3 -0.1063(r) 2 It is defined by −0.018(r), where r is equal to the radius from the center of the lens.

[0063] When the blur anisotropy values ​​at 0, 10, 20, 30, and 40 degree FOVs of the above-mentioned lens are modeled in the same manner as described above for the lens of Figures 4a-4d, the results are shown in Figure 6 (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 Figures 4a-4d, demonstrating that the lens induced an opposite blur orientation relative to the comparative lens.

[0064] The effectiveness of the lens of the present invention with induced positive blur compared to the lens described in connection with Figures 4a-4d was mathematically tested using the peripheral blur model described above. "Lens 5" is a lens of the present invention identical to Lens 1 described above (a single vision (SV) lens with -3D power), but with the variable toric power profile described above applied to the lens. The metric used to define myopia treatment effectiveness was the FOV average blur anisotropy value at zero focal blur across FOVs of 10, 20, 30, and 40 degrees. These average values ​​are shown below.

[0065] [Table 2]

[0066] The results are plotted in Figure 7. As is readily apparent from this figure, the monofocal spherical lens (Lens 1) had the lowest myopia control efficacy, as expected. Lenses 2, 3, and 4 each also had lower myopia control efficacy values ​​than the inventive lens described herein (Lens 5).

[0067] It is worth noting that the lens with the highest myopia control efficacy is still a single vision lens (Lens 5, a variable toric lens as described above), with the only difference between the two single vision lenses, Lens 5 and Lens 1 (the worst efficacy), being that Lens 5 is a single vision toric lens with a variable toric power profile, while 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. An additional "myopic control" zone is not required in this embodiment, simplifying lens design and manufacture.

[0068] Note that increasing toric power throughout the lens can affect image quality, especially if present in the central vision region. The negative impact on visual quality can be further balanced against increased effectiveness, if desired. Figure 8 shows the location relative to the center of the lens where light rays enter at various FOVs (0, 10, 20, 30, 40) for various pupil sizes (3, 4, 5, and 6 mm). At a 0-degree FOV, paraxial light rays, for example, enter a 4 mm pupil over the entire 4 mm. However, at a 10-degree FOV, light rays enter a 4 mm pupil at a maximum radial distance of 2.436 mm from the lens center. The negative impact on visual quality can be balanced against myopia-suppressing efficacy by utilizing variable toric power to induce positive peripheral blur outside the central vision region 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 completely outside the central vision area.

[0069] FIG. 9 illustrates the toric power profile of an exemplary lens in which the basic principle of the present invention (using variable toric power to induce positive blur) is balanced against degradation of visual quality. In this embodiment, where the average pupil size is assumed to be approximately 3 mm in diameter, no toric power is applied to the lens in this region, as illustrated by line 901. For the portion of the lens outside the 3 mm central optical zone, the toric power can steadily increase from 3 mm to the lens edge, as shown by line 902. In one embodiment, the variable toric power of the lens is further interrupted by one or more radial zones or regions where the toric power in the lens is reduced back to zero, as shown in areas 902 and / or 903. For individuals with larger pupil sizes, one or more such zones may be further desired to minimize degradation of vision in areas that may still be within the pupil zone.

[0070] Although the ophthalmic lenses described in detail herein are contact lenses, the principles of the invention described can be applied to any ophthalmic lens used for myopia control. For example, the optical system described can be applied to spectacle lenses. Furthermore, these principles can also be applied to implantable lenses, such as intraocular lenses or phakic lenses.

[0071] Peripheral Optical Design As mentioned above, the above results show that higher blur anisotropy values ​​correlate with better myopia control efficacy. Although the above lenses incorporate variable toric power to increase blur anisotropy, blur anisotropy can also be introduced through peripheral optical elements or features, as will be further explained below. These designs can be further adjusted to provide a desired balance of efficacy and visual acuity.

[0072] It is well known that the central vision zone of an ophthalmic lens, the central visual field of the lens inside the pupil diameter, is the most critical for visual acuity. Optical elements or aberrations that interfere with central vision have a greater impact on visual acuity than optical elements or aberrations outside the central vision zone. While pupil size can vary across the population as a whole, for younger children and teenagers who benefit most from myopia-controlling lenses, pupil size typically varies from 2.5 to 6 mm under different lighting conditions, with 4.3 mm often considered the population average for that age group and typical indoor lighting conditions.

[0073] Currently available myopia reduction contact lenses introduce a myopic defocus region or zone in the central vision region of the lens. While such myopic defocus regions in the central optical zone can provide better efficacy, they also reduce visual acuity. For myopia reduction lenses, the design must balance this reduction in visual acuity against efficacy when defocus is introduced in the central vision region. The present embodiment utilizes the above-described principles of blur anisotropy to design myopia reduction lenses with a better balance of efficacy and visual acuity by introducing myopic defocus optics in a selected manner into the peripheral region of the optical zone.

[0074] Referring back to FIG. 10 for an exemplary lens 1000 to which the design features described herein can be applied, the lens 1000 has a shape including a lens center 1002 and defined by a lens periphery 1003, and an optical zone 1004 surrounding the lens center and having an optical zone periphery 1006. As previously mentioned, the optical zone of a lens is typically considered to be the portion of the lens that a wearer sees during the normal course of wearing the lens to receive the intended vision correction. The optical zone may have a circular configuration defined by a radius (r) from the lens center. Alternatively, the optical zone may take any other suitable shape, such as may be particularly applicable to spectacle lenses rather than contact lenses. While diameters can vary, the optical zone in contact lenses is typically designed to be as large as possible without compromising mechanical properties, including handling and comfort, typically falling within the range of 6-10 mm in diameter. For purposes of describing this embodiment, the optical zone is further divided into a central optical zone 1010 surrounding the lens center 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 pupil diameter of the wearer, or the typical average pupil size in the population, which typically ranges from 2.5 to 6 mm, with an average of approximately 4.3 mm in the population.

[0075] Figure 11 illustrates the power profiles of two lens designs P1 and P2 that balance myopia control therapeutic efficacy and visual acuity compared to known lenses that incorporate only a central optic for myopia control. These designs were evaluated for efficacy and visual acuity assuming both 4mm and 5mm pupil diameters. As can be seen from Figure 11, each design includes a continuous circumferential ring with an optical design that introduces myopic defocus to the wearer at varying ADD powers and varying radial locations, as shown in the table below.

[0076] [Table 3]

[0077] [Table 4]

[0078] The phrase "ADD power" as used herein reflects the degree of myopic defocus (in diopters) introduced relative to the base power of the lens. For example, FIG. 11 reflects the base power of -3D correction, with the first myopic defocus zone of lens P1 having an ADD power of approximately 1.5D relative to the -3D baseline correction. In embodiments P1 and P2, each concentric ring with ADD power that induces myopic defocus generates myopic defocus as a ring focus around the optical axis, rather than as a single focus on the optical axis. Optical designs that generate myopic defocus as rings around the optical axis, or non-coaxial myopic ring defocus, are described in detail in U.S. Pat. No. 10,901,237, the entire contents of which are incorporated herein by reference.

[0079] Referring first to the lens designs under the 4mm pupil diameter condition, lens design P1 has only a single circumferential region 1101 in the central optical zone with an ADD power that introduces myopic defocus to the wearer, and that ADD power area is a relatively low power of 1.5D. Outside the central optical zone (in the peripheral optical zone) are continuous circumferential zones in which the ADD power increases with increasing radial distance from the lens center. In the illustrated embodiment, there are four additional continuous rings (second ring 1102, third ring 1103, fourth ring 1104, and fifth ring 1105), each with an ADD power of 3.01, 4.02, 4.99, and 6.01, respectively. Under the 5mm pupil diameter condition, the second 1102 ring is also positioned in the lens central optical zone, and only the third, fourth, and fifth continuous rings are located in the peripheral optical zones or zones.

[0080] Referring to the second lens design P2, under 4mm or 5mm pupil diameter conditions, this lens design has at least a first 1110 myopia defocus ring positioned in the central optical zone and at least a first 1113 and second 1114 myopia defocus ring positioned in the peripheral optical zone. This embodiment may further include a second myopia defocus ring 1111 positioned at least partially in the central optical zone, and may further include a third 1114 and fourth 1115 myopia defocus ring positioned in the peripheral optical zone.

[0081] The above-described peripheral FOV model as applied to the P1 and P2 lens designs produces blur anisotropy values ​​shown in Figures 12a and 12b, respectively, for the 4 mm pupil size condition, and in Figures 13a and 13b, respectively, for the 5 mm pupil size condition (reference numerals 1200, 1210, 1220, 1230, and 1240 correspond to 0, 10, 20, 30, and 40 degree FOV in each figure, respectively). For the 4 mm pupil size condition, the magnitude and position of the focal line on the retina are reflected in the following table:

[0082] [Table 5]

[0083] The average blur anisotropy value for the P1 lens is -0.1255 and for the P2 lens is -0.1615. The average blur anisotropy values ​​for the known lenses as described above in relation to the toric design (for a 4mm pupil size) are reproduced below. The lenses with non-coaxial ring foci are Lens 4 and Lens 6, which is the same as Lens 4 but does not have the small high ADD power ring in the exact center of the lens that converges to a coaxial focus in front of the retina.

[0084] [Table 6]

[0085] It is readily apparent that the P1 lens, with a mean blur anisotropy of -0.1255, has very similar myopia control efficacy to Lens 4 (-0.11) and better efficacy than Lens 6 (-0.16). The efficacy of the P2 lens is comparable to Lens 6, but slightly worse than Lenses 5, 3, and 4.

[0086] It is desirable for myopia control lenses to provide the best possible balance between efficacy and visual acuity. Based on visual acuity modeling assuming a pupil diameter of 4 mm, projected visual acuities have been established for Lenses P1 and P2, as well as the existing lenses mentioned above with the highest myopia control efficacy (Lens 4 and Lens 6), and are listed in the table below.

[0087] [Table 7]

[0088] Lens P1 has improved visual acuity over both Lens 4 and Lens 6, while Lens P2 demonstrates better visual acuity than Lens 4 and substantially similar visual acuity to Lens 6. For the lenses listed above, the following table shows the efficacy and visual acuity values ​​for each for ease of reference.

[0089] [Table 8]

[0090] In summary, Lens P1 has an effectiveness level close to that of Lens 4, but with substantially improved visual acuity (approximately a 2 1 / 2 line improvement). Lens P1 also has improved effectiveness and approximately a 1 line improvement in visual acuity over Lens 6. Lens P2 has slightly worse effectiveness than Lens 4, but with approximately a 1 1 / 2 line improvement in visual acuity, and has substantially similar effectiveness and visual acuity to Lens 6.

[0091] For the 5 mm pupil size condition, the blur anisotropy values ​​are shown in Figures 13a and 13b. For comparison, the blur anisotropy values ​​for the above-mentioned Lenses 6 and 4, assuming a 5 mm pupil size condition, are shown in Figures 14a and 14b, respectively. For the 5 mm pupil size condition, the magnitude and position of the focal line on the retina are reflected in the table below for P1, P2, and Lens 4.

[0092] [Table 9]

[0093] From the table above, the average blur anisotropy for lens P1 is −0.0812, for lens P2 it is −0.0931, and for lens 4 it is −0.1177. Thus, both P1 and P2 demonstrate greater effectiveness than lens 4.

[0094] Based on visual acuity modeling assuming a pupil diameter of 5 mm, projected visual acuities have been established for lenses P1 and P2, as well as the existing lenses mentioned above with the highest myopia suppression efficacy (lenses 4 and 6), and are listed in the table below.

[0095] [Table 10]

[0096] Lens P1 also has improved visual acuity over both Lens 2 and Lens 4, while Lens P2 has the improved visual acuity of Lens 4 and half a line worse visual acuity than Lens P1. For the lenses listed above, the following table shows the efficacy and visual acuity values ​​for each for ease of reference.

[0097] [Table 11]

[0098] In summary, Lens P1 has improved effectiveness over both Lens 6 and Lens 4, and substantially improved visual acuity (approximately 2 lines) over Lens 4, as well as substantially similar visual acuity to Lens 6. Lens P2 also has better effectiveness than both Lens 6 and Lens 4, and improved visual acuity (approximately 1 line) over Lens 4, with approximately 1 / 2 line worse visual acuity compared to Lens 6. The above-described embodiments refer to the objective of increasing positive blur anisotropy, assuming horizontal peripheral vision. While the foregoing description relates to embodiments of the present invention, other and further embodiments of the present invention may be devised without departing from the basic scope thereof, the scope of which is limited only by the scope of the claims that follow. For example, it is contemplated that any of the features shown in any of the embodiments described herein may be incorporated with any of the features shown in any of the other embodiments described herein or incorporated by reference herein and still fall within the scope of the present invention.

[0099] [Embodiment] (1) An ophthalmic lens, a shape defined by the lens center and the lens periphery; an optical zone surrounding the lens center and having an optical zone periphery, the optical zone having a refractive power selected to correct a myopic condition of a user of the lens; the lens has a toric power at the center of the lens that is less than a toric power at the periphery of the optical zone, and has a variable toric power that increases radially over at least a portion of the lens to at least the periphery of the optical zone; An ophthalmic lens, wherein the variable toric power has a predetermined power profile that induces a positive visual field average blur anisotropy for the user at or in front of the user's retinal plane. (2) An ophthalmic lens according to embodiment 1, wherein the visual field average blur anisotropy is positive at the retinal plane over a visual field 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 periphery of the optical zone. (4) The variable toric power is expressed by the formula: Toric power = 0.0642(r) 3 -0.1063(r) 2 2. The ophthalmic lens of embodiment 1, wherein the ophthalmic lens is defined by −0.018(r), where r is equal to the radius from the center of the lens. (5) An ophthalmic lens as described in embodiment 1, wherein the lens further includes a lens central region centered on the lens center within the optical zone and having a lens central region diameter, the lens having zero toric power in the lens central region, and the variable toric power extending radially outward from the lens central region to the outer periphery of the optical zone.

[0100] (6) An ophthalmic lens according to embodiment 5, wherein the diameter of the lens central region is designed to match the average pupil diameter of a predetermined population. (7) The ophthalmic lens according to embodiment 5, wherein the diameter of the lens central region is 3 to 5 mm. (8) An ophthalmic lens according to embodiment 5, wherein the variable toric power profile between the lens central region and the optical zone outer periphery is interrupted by at least one radial segment in which the toric power is zero. (9) An ophthalmic lens as described in embodiment 5, wherein the variable toric power profile between the lens central region and the optical zone outer periphery is interrupted by first and second radial segments in which the toric power is zero. (10) An ophthalmic lens according to claim 1, wherein the lens has a myopia-suppressing efficacy greater than that of a comparable spherical single vision lens of the same refractive power that does not have the variable toric power profile.

[0101] (11) The ophthalmic lens of embodiment 1, wherein the lens is a contact lens. (12) The ophthalmic lens according to claim 1, wherein the lens is a spectacle lens. (13) The ophthalmic lens according to embodiment 1, wherein the lens is an intraocular lens or a phakic lens. (14) The ophthalmic lens of embodiment 1, wherein the variable toric power profile is on the anterior surface of the lens. (15) The ophthalmic lens of embodiment 1, wherein the variable toric power profile is on the posterior surface of the lens.

[0102] (16) A method for designing an ophthalmic lens for human use, comprising: creating a lens design for an ophthalmic lens having a shape defined by a lens center and a lens outer edge, and an optical zone surrounding the lens center and having an optical zone perimeter, the optical power of the optical zone being selected to correct the person's myopic vision; applying to the lens design a variable toric power profile across at least a portion of the optical zone of the lens, the variable toric power profile having a toric power that increases radially from the lens center and configured to induce a positive visual field average blur anisotropy in the person at or in front of the person's retinal plane. (17) The method described in embodiment 16, wherein the visual field average blur anisotropy is positive at the retinal plane over a visual field of 0 to 40 degrees. (18) The method of claim 17, wherein the variable toric power increases continuously from the lens center to the optic zone periphery. (19) The variable toric power is expressed by the formula: Toric power = 0.0642(r) 3 -0.1063(r) 2 18. The method of claim 17, wherein the lens is defined by −0.018(r), 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 central region within the optical zone and centered about the lens center, and the lens has zero toric power within the lens central region.

[0103] (21) The method according to embodiment 20, wherein the diameter of the lens central region is 3 mm to 5 mm. (22) The method of embodiment 17, 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 where the toric power is zero. (23) The method of claim 17, wherein the lens has a myopia-suppressing efficacy greater than a comparable spherical single vision lens of the same 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.

[0104] (26) The method of embodiment 17, wherein the lens is an intraocular lens or a phakic lens. (27) The ophthalmic lens of embodiment 17, wherein the variable toric power profile is on the anterior surface of the lens. (28) The ophthalmic lens according to embodiment 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 shape defined by a lens center and a lens periphery, an optical zone surrounding the lens center within the lens periphery and defined by an optical zone periphery, the optical zone having a predetermined optical power selected to correct a myopic condition of the wearer; A contact lens comprising: a variable toric power profile applied to at least a portion of the optical zone, the variable toric power profile being configured to induce a positive visual field average blur anisotropy for the wearer at or in front of the wearer's retinal plane. (30) The contact lens of embodiment 29, wherein the visual field average blur anisotropy is positive at the retinal plane over a visual field of 0 to 40 degrees.

[0105] (31) The contact lens of embodiment 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 embodiment 31, wherein the variable toric power increases continuously from the center of the lens to at least the outer periphery of the optical zone. (33) The variable toric power is expressed by the formula: Toric power = 0.0642(r) 3 -0.1063(r) 2 32. The contact lens of embodiment 31, wherein the radius is defined by −0.018(r), where r is equal to the radius from the center of the lens. (34) The contact lens of embodiment 31, wherein the lens further comprises a lens central region centered at the lens center, within the optical zone, and having a lens central diameter, the lens having zero toric power in the lens central region, and the variable toric power extending radially outward from the lens central region to at least the outer periphery of the optical zone. (35) The contact lens of embodiment 34, wherein the lens central diameter substantially corresponds to the average pupil diameter of a predetermined population.

[0106] (36) The contact lens according to embodiment 34, wherein the lens center diameter is 3 to 5 mm. (37) The contact lens of embodiment 34, wherein the variable toric power profile between the lens central region and the optical zone periphery is interrupted by at least one radial segment in which the toric power is zero. (38) The contact lens of embodiment 34, wherein the variable toric power profile between the lens central region and the optical zone periphery is interrupted by first and second radial segments in which the toric power is zero. (39) The contact lens of embodiment 31, wherein the lens has a myopia-suppressing efficacy greater than a comparable spherical single vision lens of the same refractive power but without the variable toric power profile.

Claims

1. An ophthalmic lens, a shape defined by the lens center and the lens periphery; an optical zone surrounding the lens center and having an optical zone periphery, the optical zone having a refractive power selected to correct a myopic condition of a user of the lens; the lens has a toric power at the center of the lens that is less than a toric power at the periphery of the optical zone, and has a variable toric power that increases radially over at least a portion of the lens to at least the periphery of the optical zone; An ophthalmic lens, wherein the variable toric power has a predetermined power profile that induces a positive visual field average blur anisotropy for the user at or in front of the user's retinal plane.

2. The ophthalmic lens of claim 1 , wherein the field-average blur anisotropy is positive at the retinal plane over 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 lens center to the optic zone periphery.

4. The variable toric power is determined by the formula: Toric Power=0.0642(r) ３ -0.1063(r) ２ 10. The ophthalmic lens of claim 1, wherein the ophthalmic lens is defined by -0.018(r), where r is equal to the radius from the center of the lens.

5. 2. The ophthalmic lens of claim 1, wherein the lens further comprises a lens central region centered on the lens center within the optical zone and having a lens central region diameter, the lens having zero toric power in the lens central region, and the variable toric power extending radially outward from the lens central region to the outer periphery of the optical zone.

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

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

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

9. 6. The ophthalmic lens of claim 5, wherein the variable toric power profile between the lens central region and the optical zone periphery is interrupted by first and second radial segments where the toric power is zero.

10. 10. The ophthalmic lens of claim 1, wherein the lens has a myopia-suppressing efficacy greater than a comparable spherical single vision lens of the same refractive power 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 anterior 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. 1. A method for designing an ophthalmic lens for human use, comprising: creating a lens design for an ophthalmic lens having a shape defined by a lens center and a lens outer edge, and an optical zone surrounding the lens center and having an optical zone perimeter, the optical power of the optical zone being selected to correct the person's myopic vision; applying to the lens design a variable toric power profile across at least a portion of the optical zone of the lens, the variable toric power profile having a toric power that increases radially from the lens center and configured to induce a positive visual field average blur anisotropy in the person at or in front of the person's retinal plane.

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

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

19. The variable toric power is determined by the formula: Toric Power=0.0642(r) ３ -0.1063(r) ２ 18. The method of claim 17, wherein the radii are defined by -0.018(r), where r is equal to the radius from the center of the lens.

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

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

22. 18. The method of claim 17, 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 where the toric power is zero.

23. 18. The method of claim 17, wherein the lens has a myopia-suppressing efficacy greater than a comparable spherical single vision lens of the same power but without the variable toric power profile.

24. 18. 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. 18. The method of claim 17, wherein the lens is an intraocular lens or a phakic lens.

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

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

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

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

31. 30. 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. 32. The contact lens of claim 31, wherein the variable toric power increases continuously from the lens center to at least the optic zone periphery.

33. The variable toric power is determined by the formula: Toric Power=0.0642(r) ３ -0.1063(r) ２ 32. The contact lens of claim 31, wherein the radius is defined by -0.018(r), where r is equal to the radius from the center of the lens.

34. 32. The contact lens of claim 31, wherein the lens further comprises a lens central region centered at the lens center, within the optical zone, and having a lens central diameter, the lens having zero toric power in the lens central region, and the variable toric power extending radially outward from the lens central region to at least the outer periphery of the optical zone.

35. 35. The contact lens of claim 34, wherein the lens central diameter substantially corresponds to the average pupil diameter of a predetermined population.

36. 35. The contact lens of claim 34, wherein the lens central diameter is 3 to 5 mm.

37. 35. The contact lens of claim 34, wherein the variable toric power profile between the lens central region and the optical zone periphery is interrupted by at least one radial segment where the toric power is zero.

38. 35. The contact lens of claim 34, wherein the variable toric power profile between the lens central region and the optic zone periphery is interrupted by first and second radial segments where the toric power is zero.

39. 32. The contact lens of claim 31, wherein the lens has a myopia-suppressing efficacy greater than a comparable spherical single vision lens of the same refractive power but without the variable toric power profile.

Images