Myopia Control Lenses and Related Methods

Abstract

An ophthalmic lens for myopia control. The first surface of the lens varies across the lens to form a first surface power map. The second surface of the lens varies across the lens to form a second surface power map. Each of the first and second surface power maps includes a helix. The helices formed by the first and second surface power maps twist in opposite directions. Related methods are also described.

Description

Technical Field

[0001] The present invention relates to ophthalmic lenses and methods for reducing myopia progression (i.e., myopia control). More specifically, but not exclusively, the present invention relates to ophthalmic lenses for myopia control, the ophthalmic lenses having a first surface and a second surface, the first and second surfaces providing corresponding first and second surface power maps, wherein the first and second surface power maps include counter-rotating spirals. The present invention also relates to methods of manufacturing and using such lenses. Background Art

[0002] A myopia control lens is an ophthalmic lens that attempts to control the progression of myopia in a wearer. This is typically achieved by subdividing the ophthalmic lens into a plurality of zones. The zones in a first subset of the plurality of zones are provided with a first lens power corresponding to a first focal distance (e.g., for correcting the hyperopia of an ametropic eye). The zones in a second subset of the plurality of zones have a second lens power selected to provide myopic defocus.

[0003] In the case of contact lenses for myopia control, the plurality of zones are typically formed as concentric circles centered on the optical axis of the contact lens, the concentric circles alternating between a first lens power that provides corrected vision and a second lens power that provides myopic defocus. Thus, the power map of a myopia control contact lens includes at least two alternating concentric circles of first and second lens powers. However, under lower light conditions, the pupil of the wearer dilates to provide a larger aperture for the incident light, increasing the amount of light received into the eye, thereby providing improved low-light vision. As the conditions brighten, the pupil contracts to provide a smaller aperture, thereby limiting the amount of light received into the eye. As the pupil of the wearer dilates and contracts, the number of concentric rings on the contact lens that straddle the wearer's entrance pupil also changes. As the pupil dilates, a greater number of concentric rings will straddle the wearer's entrance pupil. Similarly, as the pupil contracts, a smaller number of concentric rings will straddle the wearer's entrance pupil. Since the concentric rings alternate between a first lens power and a second lens power, the amount of the second lens power that provides myopic defocus and that straddles the wearer's entrance pupil will vary as the pupil of the wearer contracts and dilates. In some cases, the pupil may even contract to the extent that none of the second lens powers that provide myopic defocus straddle the wearer's entrance pupil, resulting in the lens being unable to effectively control myopia progression.

[0004] In addition to varying pupil size, lens decentration, and in the case of spectacle lenses, movement of the wearer's eyes behind the lens also reduces the ability of the lens to provide effective myopia control. Each of the above factors causes a change in the ratio of the first and second lens powers.

[0005] Several lens designs have been described for reducing myopia progression. MISIGHT (CooperVision) is the first contact lens to receive regulatory approval in the United States. The MISIGHT contact lens is a bifocal contact lens that provides myopic defocus images at both near and far viewing distances. The bifocal design includes a central distance correction zone defined by alternating rings of different optical powers. Another concentric ring lens design is known as the Defocus Soft (Disc) lens and was developed by The Hong Kong Polytechnic University (HKPU) and is being commercialized by Vision Science and Technology Co., Ltd. HKPU and Hoya Vision Care have developed a myopia control spectacle lens called the Defocus Incorporated Multiple Segments (DIMS) lens, called MyoSmart (Hoya). Additionally, Sightglass Vision has developed another spectacle lens for myopia control. Examples of myopia control ophthalmic lenses have been described in the patent literature, including the following: US7766478; US7832859; US8240847; USRE47006; US8950860; US9594259; US9829722; US10061143; US10416476; US10268050; US10429670; US20190212580; US20180275427; US20160377884; and US20170115509.

[0006] It is important to ensure that a myopia control lens is able to reduce the formation of additional unwanted images. If the portion of the lens that provides myopic defocus also forms additional images, then there is a possibility that the wearer of the lens may simply "tune" into the additional images rather than exercising the accommodation ability of the eye. This is undesirable. It will be appreciated that if the lens design includes separate regions, where only some regions are dedicated to myopia control, then the above limitation of preventing the formation of accidental images applies to those regions dedicated to myopia control and not to the entire lens.

[0007] The present invention seeks to alleviate the problems mentioned above. Alternatively or additionally, the present invention seeks to provide an improved ophthalmic lens for myopia control. Summary of the Invention

[0008] According to a first aspect, the present invention provides an ophthalmic lens for controlling myopia progression. A first surface of the ophthalmic lens is shaped to form a first surface power map. A second surface of the ophthalmic lens is shaped to form a second surface power map. The first surface power map includes a helix. The second surface power map also includes a helix. The helices formed by the first and second surface power maps twist in opposite directions.

[0009] The overall power map of the contact lens is determined by the superposition of the first surface power map and the second surface power map. The spirals provided by the first and second surface power maps twist in opposite directions. Thus, the first and second surface power maps can be said to include counter-rotating spirals. The superposition of two counter-rotating spirals formed by the first surface power map and the second surface power map produces a lens power map that approximates an alternating annular ring or a multi-segment defocused pseudo-dartboard pattern. The overall lens power map varies between a first lens power that provides distance vision and a second lens power that provides myopic defocus. Since the ophthalmic lens is intended to be used as a myopia control lens, the age of the wearer of the ophthalmic lens is typically between about 5 years and 18 years, and thus, it is likely that the wearer's eyes will be able to adapt. Thus, it will be appreciated that although the first lens power is selected for distance vision, due to the wearer's adaptability, the wearer can also view up close through the portion of the lens that provides the first lens power.

[0010] A contact lens having a power map that approximates a pseudo-dartboard pattern can effectively provide myopia control. In the case where the pupil size of the wearer changes, such a lens power map also provides a more stable ratio of lens powers (i.e., the ratio of the lens power that provides myopic defocus to the lens power that provides distance vision focus). As the light conditions change, the pupil of the wearer will dilate and contract to regulate the amount of light received into the eye. As the conditions brighten, the pupil contracts to reduce the amount of light allowed into the eye. As the conditions darken, the pupil dilates to allow more light to enter the eye. Some prior art myopia control contact lenses use alternating concentric rings of a first lens power that provides distance vision focus and a second lens power that provides myopic defocus, such as a central circle of the first lens power surrounded by an outer circle of the second lens power. As the pupil of the wearer dilates and contracts, these contact lenses suffer from variations in the ratio of lens powers (i.e., the ratio of the lens power that provides myopic defocus to the lens power that provides distance vision focus) across the pupil of the wearer. These variations can weaken the ability of the lens to provide effective myopia control. Thus, the contact lens according to the present invention can provide effective myopia control in the presence of different pupil dilations.

[0011] The helical power maps disclosed herein can provide a constant ratio of the lens power providing myopic defocus to the lens power providing far focus across the diameter over the full range encompassing the helix. Thus, as the pupil constricts or dilates, a contact lens having a helical power map can maintain a substantially constant ratio of focus to myopic defocus (where the helix covers the entire lens) or a monotonically varying ratio (where the helix covers only a radial sub-part of the lens). The pseudo-dartboard pattern provided by the superposition of two counter-rotating helices also provides the same benefit. Thus, a contact lens having a pseudo-dartboard power map can reduce the variation in the ratio of myopic defocus to far focus under variable lighting conditions.

[0012] Those skilled in the art will appreciate that in the case where the power map varies smoothly (e.g., as a sine curve), the power map will include lens powers other than just the first lens power associated with far vision focus and the second lens power associated with myopic defocus. In such a case, the power map will also include regions having lens powers between the first and second powers. It will be appreciated that this does not affect or detract from the advantage described above of providing a consistent and stable variation in the ratio of focus to myopic defocus across the pupil location of the wearer. Those skilled in the art will appreciate that this advantage stems from the fact that for helical and pseudo-dartboard power maps, the composition of the lens power at a particular radius does not vary with the radial distance from the optical axis of the lens.

[0013] According to a second aspect of the invention, there is also provided a method of manufacturing an ophthalmic lens for myopia control. The method includes operating a lathe to shape at least one of the first and second surfaces of: a lens, a mold of the lens, or an insert for a mold for manufacturing the lens. The first surface is shaped such that it forms a first surface power map. The second surface is shaped such that it forms a second surface power map. Each of the first surface power map and the second surface power map includes a helix. The helices formed by the first surface power map and the second surface power map twist in opposite directions.

[0014] According to a third aspect of the invention, there is also provided a method of using an ophthalmic lens described herein. The method can effectively reduce the progression of refractive errors, such as reducing the progression of myopia or hyperopia. The method includes the step of providing an ophthalmic lens to a person to whom the eye can adapt. The method can include the step of providing an ophthalmic lens to a person from about 5 years old to about 18 years old. The providing can be performed by an eye care professional, such as an optician or an optometrist. Alternatively, the providing can be performed by a lens dispenser arranged to deliver the ophthalmic lens to the lens wearer.

[0015] Of course, it will be understood that features described with respect to one aspect of the invention can be incorporated into other aspects of the invention. For example, the methods of the invention can incorporate any features described with reference to the devices of the invention and vice versa. Description of the Drawings

[0016] Embodiments of the present invention will now be described by way of example with reference only to the attached schematic diagrams:

[0017] Figure 1 Showing a contact lens according to an exemplary embodiment of the present invention;

[0018] Figure 2 Showing a first surface power map of the optical zone of a contact lens according to a first embodiment of the present invention;

[0019] Figure 3 Showing a second surface power map of the optical zone of the contact lens of the first embodiment;

[0020] Figure 4 Showing a lens power map of the optical zone of the contact lens of the first embodiment;

[0021] Figure 5 Showing a power map of the optical zone of a contact lens according to a second embodiment;

[0022] Figure 6 Showing a flowchart illustrating the steps of a method according to a fifth embodiment of the present invention; and

[0023] Figure 7 Showing an ophthalmic lens according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0024] According to a first aspect, the present invention provides an ophthalmic lens for myopia control. The first surface of the ophthalmic lens varies to form a first surface power map. The second surface of the ophthalmic lens varies to form a second surface power map. Those skilled in the art will understand that the variation of the surface includes the variation of the curvature of the surface. Each of the first and second surface power maps includes a helix. The helices provided by the first and second surface power maps twist in opposite directions.

[0025] The helix formed on each of the first and second surfaces can be formed by varying the power of the corresponding surface generally periodically radially outward from the optical axis of the lens and angularly about the optical axis of the lens.

[0026] Those skilled in the art will understand that the first surface power map is not necessarily formed by the entire first surface. In fact, the first surface power map can be formed on a part of the first surface. In this case, the variation of the part of the first surface outside is not related to the first surface power map. This also applies to the second surface and the second surface power map. For example, in the case of a contact lens, the surface power map may be formed only by the optical zone of the contact lens, rather than by the surrounding peripheral zone. Therefore, in this case, the part of the surface corresponds to the optical zone of the contact lens.

[0027] An ophthalmic lens having first and second surfaces with counter-rotating spirals can provide a lens power profile that is effective in the context of myopia control. It is believed that myopic defocus affects eye growth. However, while myopia control lenses have been established as effective in suppressing myopia progression, the mechanism by which they achieve this effect is not fully known or understood. The effectiveness of the structures and lens designs currently disclosed for use in myopia control does not depend on the correctness of the above theory regarding the exact mechanism by which myopia control lenses work.

[0028] The ophthalmic lens may be a contact lens. Alternatively, the ophthalmic lens may be an intraocular lens or an eyeglass lens.

[0029] It will be appreciated that a change in the first surface power map does not necessarily match a change in the second surface power map. In fact, the first surface power map varies independently of the second surface power map, and vice versa. Accordingly, each of the subsequently described optional features of the characteristics of the radial and angular variations applies to the first and second surface power maps together or separately.

[0030] The spiral may be formed on a portion of the lens. For example, in the case of a contact lens, the spiral may be formed in the optical zone of the lens.

[0031] In the case of a contact lens, it will be appreciated that the lens will include an optical zone that can provide vision correction. A contact lens according to an embodiment of the present invention may also include a surrounding peripheral zone that does not provide additional focusing or vision correction. The peripheral zone may only be used to help hold the contact lens in position on the wearer's eye. Accordingly, those skilled in the art will appreciate that the surface power map is defined by the variation of the first surface across the optical zone of the lens. In the context of the present invention, the variation of the lens surface outside the optical zone (e.g., in the peripheral zone) is not considered to define the surface power map. Similar considerations apply to intraocular lenses, which may also include an optical zone and (optionally) a peripheral zone.

[0032] According to an embodiment of the present invention, depending on the type of contact lens, the optical zone of the contact lens may have a diameter between 4 mm and 9 mm. For example, the diameter of the optical zone may be about 5 mm, or about 6 mm, or about 7 mm or about 8 mm. The diameter of the optical zone of the contact lens may be between 7 mm and 9 mm. The optical zone contains an optical axis corresponding to the geometric center of the optical zone.

[0033] The period of the radial variation (e.g., the radial variation of both the first and second surface power maps) may be greater than 100 microns. The period of the angular variation (e.g., the angular variation of both the first and second surface power maps) may be greater than 6 degrees.

[0034] For the first and / or second surface power maps, one or both of the radial and angular variations may be constant across the power map.

[0035] The period of the radial variation may be greater than 200 microns, preferably greater than 400 microns, and more preferably greater than 800 microns. The period of the angular variation may be greater than 6 degrees, preferably greater than 9 degrees, preferably greater than 18 degrees, and more preferably greater than 36 degrees. The period of the radial variation may be between 0.1 mm and 10 mm. The period of the radial variation may be between 0.5 mm and 5 mm. The period of the radial variation may be between 1 mm and 2 mm.

[0036] The period of the angular variation may be less than 180 degrees, preferably less than 90 degrees, and more preferably less than 45 degrees. The period of the angular variation may be between 180 degrees and 9 degrees. The period of the angular variation may be between 120 degrees and 24 degrees. The period of the angular variation may be between 90 degrees and 36 degrees. Each of the spirals may include more than two, preferably more than 4, and more preferably more than 8 arms. Those skilled in the art will understand that the period of the angular sine variation determines the number of arms on the spiral. Thus, the radial variation may have a period greater than 100 microns, and the angular variation may have a period greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and more preferably greater than 36 degrees. The radial variation may have a period greater than 200 microns, and the angular variation may have a period greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and more preferably greater than 36 degrees. The radial variation may have a period greater than 400 microns, and the angular variation may have a period greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and more preferably greater than 36 degrees. The radial variation may have a period greater than 800 microns, and the angular variation may have a period greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and more preferably greater than 36 degrees. It will be understood that the above applies to either surface of the lens.

[0037] The spirals formed on the first and second surface power maps may twist in opposite directions but are otherwise generally the same.

[0038] The power may vary smoothly across the power map. The power may vary continuously, without any discontinuities. The power may vary across the portion at a rate of less than 80 D / mm, preferably less than 40 D / mm, more preferably less than 20 D / mm. The surface may vary smoothly across the portion. The surface may vary continuously, without any discontinuities. Smoothly varying the power across the power map may result in a lens surface profile that is easier to manufacture using a lathe. Those skilled in the art will appreciate that manufacturing an ophthalmic lens using a lathe may include using the lathe to shape the surface of one or more of the lenses (e.g., contact lenses), the molds for the lenses (e.g., the molds for contact lenses), and the inserts for the lens molds (e.g., the inserts for contact lens molds). It may be difficult to achieve sharp transitions and features using a lathe. Thus, lenses having such features generally cannot be reproduced as desired or to the defined requirements when manufactured using a lathe. Thus, it will also be appreciated that the term smooth in this context means smooth enough to enable the desired shaping of the surface of the lens, the mold for the lens, or the insert for the lens mold using a lathe.

[0039] The power map may vary as a square wave in one or both of the radial and angular directions. The power map may vary as a circular square wave in one or both of the radial and angular directions. The power map may vary as a sine curve in one or both of the radial and angular directions.

[0040] The radial and angular variations may be associated with corresponding waveforms. Additionally, the power distribution of the waveform may be symmetric, with the balance between myopic defocus and distance vision correction being substantially equal. Alternatively, the power distribution may be biased towards vision correction or myopic defocus. Thus, the power distribution of the waveform may be asymmetric in one or both of the radial and angular directions.

[0041] The period of one or both of the radial and angular variations may be substantially constant across the power map. Embodiments of the present invention in which the radial and angular variations are substantially constant produce lenses having a surface profile that is easier to manufacture using a lathe.

[0042] The period of one or both of the radial and angular variations may vary depending on either or both of the radial distance from the optical axis of the lens and the angular position around the optical axis. Embodiments of the present invention in which the period of one or both of the radial and angular variations varies according to the position on the lens may provide lenses in which the characteristics of the helix (e.g., its rotation rate or arm width) vary in different regions of the optical zone. It will be appreciated that the optical axis of a contact lens is typically also the center of the optical zone of the contact lens.

[0043] The change in the period of the radial variation can be separated by a blending region, such as a linearly varying lens power. Such a blending region can include concentric rings of linearly varying period between a first region having a first period of radial variation and a second region having a second period of radial variation. Thus, the blending region can provide a smooth transition between regions of different period radial variation. Regions of different period radial variation may be separated by two blending regions and an intervening region of substantially constant lens power. The blending region can have a width (in plan view) of from about 25 microns to about 200 microns.

[0044] Each arm of one or both of the spirals may twist between a quarter and 40 revolutions. Those skilled in the art will appreciate that the number of revolutions by which the arms of the spiral twist is determined by the period of the radial variation and the radius of the surface power map.

[0045] The ratio of the period of the radial variation to the period of the angular variation may be greater than 0.1 mm:6°. Each arm of one or both of the spirals may be wider than 0.1 mm, preferably wider than 0.5 mm, more preferably wider than 1 mm. Each arm may be between 0.1 mm and 3 mm wide. Each arm may be between 0.25 mm and 2 mm wide. Each arm may be between 0.5 mm and 1 mm wide. Those skilled in the art will understand that the width of the arm at a given radius is defined as its perpendicular width (i.e., its width in a direction perpendicular to the given radius). In this context, the width of the arm is defined as the distance between two points closely adjacent to each side of the arm, the two points having either a maximum or minimum gradient, and the power undergoing a single positive or negative offset between the gradients. Those skilled in the art will appreciate that such a definition of width provides a straight-line measurement of the arm width along the tangent to the circle of the given radius. Those skilled in the art will further appreciate that the width measurement under this definition will be different from the measurement of the width of the arm as an arc of a circle of the given radius. Unlike the width measurement under the straight-line width definition, such an arc-based measurement will be proportional to the angular period. The magnitude of the difference between the widths obtained by the two methods will depend on the angular period for the particular case at hand.

[0046] Each of the spirals may include more than 2 arms, preferably more than 4 arms, more preferably more than 8 arms, and more preferably more than 16 arms.

[0047] Each arm of the spiral may twist at least a half turn, preferably at least one full turn, more preferably at least one and a half turns, and more preferably at least two turns.

[0048] Each arm of the helix may extend from a portion of the optical axis to the periphery of the power map. A contact lens according to an embodiment of the invention in which the arms of the helix extend from the optical axis of the lens to the periphery of the power map may provide a substantially constant ratio of a first lens power (corresponding to far vision focusing) to a second lens power (corresponding to myopic defocus) in the case of a change in pupil dilation. Compared to a concentric annular lens design, such embodiments may provide a more consistent myopic defocus image under different light conditions. If the ophthalmic lens is a contact lens, then compared to a concentric ring contact lens design, the myopic defocus image may be more consistent when the lens is decentered. If the ophthalmic lens is an eyeglass lens, then compared to other eyeglass lens designs, the myopic defocus image may be more consistent when the eye rotates.

[0049] It will be appreciated that the lens will have an average lens power. Additionally, it will be appreciated that the lens will be divided into a first region of the lens having a lens power greater than the average and a second region having a lens power less than the average. The ratio of the first region to the second region may be between 10:1 and 1:10. The ratio of the first region to the second region may be between 5:1 and 1:5. The ratio of the first region to the second region may be between 3:1 and 1:3. The ratio of the first region to the second region may be between 2:1 and 1:2. The ratio of the first region to the second region may be approximately 1:1.

[0050] The power map may include a central region and an outer region. The central region may closely surround the optical axis of the lens. The outer region may closely surround the central region. The power of the central region may not vary periodically across the central region. The outer region may include a helical power profile. Thus, the outer region may include angular and radial variations in the power of the first and / or second surface power maps. A helix may be formed in the central region. In this case, the helix may not extend into the outer region. Alternatively, the helix may be formed in the outer region. In this case, the helix may not extend into the central region. Alternatively, the central region may include a helical power profile and the outer region does not vary periodically across the outer region (e.g., is substantially constant). A non-varying region of the lens may provide vision correction, e.g., by including a power for myopic correction (i.e., providing clear distance vision). Alternatively, the non-varying region of the lens may not provide any vision modification and thus only provides a portion of the lens through which normal focused vision is possible. Providing a contact lens in which the central or outer region has a lens power that is not affected by periodic power variations may allow the lens to provide both myopia control and correction simultaneously.

[0051] Accordingly, one or more portions of the lens may be arranged to provide functions other than myopia control. For example, the central region of the lens may have a lens power selected to provide vision correction (e.g., myopia correction). It will be appreciated that such regions of the lens may be arranged to provide any type of vision correction achievable in known contact lenses and spectacle lenses. Thus, the helix formed by the first and second surface power maps may exist only in one or more specific myopia control portions of the lens. Such portions of the lens may be of any shape, such as an annular ring, a strip projecting radially outward from the center of the lens, or one or more of the alternating portions of a pseudo bull's-eye pattern. The helical power profile formed by the first and second surface power maps may be interrupted by an annular ring portion of corrective lens power at a predetermined radial distance from the optical axis of the lens. The lens may include a plurality of such corrective ring portions. The helical power profile may continue between the corrective ring portions.

[0052] A contact lens according to an embodiment of the present invention may include a surrounding peripheral zone that does not provide additional focusing or vision correction and is only used to help hold the contact lens in position on the wearer's eye.

[0053] When worn on the eye, the contact lens is located on the cornea, and the optical zone generally covers the wearer's pupil in a conventional manner. Accordingly, the diameter of the central region may be less than 50% of the diameter of the power map, preferably less than 40%, more preferably less than 30%. The central region may be less than the smallest pupil size of the wearer of the contact lens. Such embodiments of the present invention may provide a central region that is less than the smallest pupil size of the wearer. Embodiments of the present invention having a central region that is less than the smallest pupil size of the wearer may maintain vision correction under varying light conditions.

[0054] The lens may include a transition region. The transition region may surround the central region. The outer region may surround the transition region. The power of the transition region may vary to provide a smooth transition between the central and outer regions. Embodiments of the present invention providing a smooth transition between the central and outer regions may make it easier to manufacture using a lens lathe, a mold for such a lens, or an insert for such a lens mold. Thus, those skilled in the art will appreciate that, in this context, smooth means that the lens profile must be smooth enough to be produced using a lathe. The transition region may also vary as a helix, such as a continuation of the helix formed in the outer region. In such embodiments, the magnitude of the helix formed in the transition region may decay (e.g., linearly) between the outermost radius and the innermost radius of the transition region. The transition helix may decay from a magnitude equal to the helix formed in the outer region (e.g., at the outermost radius) to zero (e.g., at the innermost radius).

[0055] The periods and phases of the radial and angular variations of the second surface power map may be the same as those of the first surface power map. Thus, the spirals provided by the first and second surface power maps may be the same, but in opposite twisting directions. Providing first and second surface power maps that include counter-rotating spirals can give a lens power map that approximates a dart-like pattern of alternating annular rings. Those skilled in the art will appreciate that the lens power map is formed by the superposition of the power maps of each of the first and second surfaces. Thus, it will also be appreciated that the pseudo-dartboard pattern is provided by the combination of the first and second surface power maps, each of which retains the previously described advantages of being easy to manufacture. Thus, such embodiments can enable lenses with a pseudo-dartboard power map to be more easily manufactured using a lathe.

[0056] The lens power map may include a plurality of zones. The plurality of zones may provide a first power corresponding to the desired vision correction or a second power corresponding to the desired myopic defocus. Thus, the first power may be between 0 diopters (D) and -10 D. The first power may be from -0.25 D to -6.00 D. The second power provided in the lenses of the present invention may be more positive than the first power of the lens. For example, the second power may be 1 D to 5 D more positive than the first power. The second power may be 1 D to 4 D more positive than the first power. The second power may be 2 D to 3 D more positive than the first power. The second power may vary; for example, this may occur when the powers of the discrete defocus zones are more positive than the first power, such that some of the zones may have a second power of +1 D, some zones may have a second power of +2 D, and some zones may have a second power of +3 D. The variation of the second power may occur on the same arm or may occur on different arms. These zones may be arranged on the lens such that they alternate radially and / or angularly between the first and second powers.

[0057] Contact lenses according to embodiments of the present invention may include a ballast to orient the lens when placed on the eye of a wearer. The contact lens may provide a particular benefit to the wearer in a given orientation. Incorporating a ballast into an embodiment of the contact lens of the present invention will cause it to rotate to a predetermined rest angle under the action of the wearer's eyelid when placed on the eye of the wearer; for example, the ballast may be a wedge, and the rotation may be the result of the action of the eyelid on the wedge. By placing a ballast in the contact lens, it is possible to ensure that the rest angle corresponds to a lens orientation that provides a special benefit to the wearer.

[0058] According to a second aspect, the present invention provides a method of manufacturing an ophthalmic lens (such as a contact lens) for myopia control. The method includes operating a lathe to shape a first and a second surface of one of: a lens (such as a contact lens), a mold of the lens (such as a mold of a contact lens), or an insert of a mold for manufacturing the lens (such as an insert of a mold for a contact lens). The first surface forms a first surface power map. The second surface forms a second surface power map. Each of the first and second surface power maps includes a helix. The helices formed by the first and second surface power maps twist in opposite directions.

[0059] Each of the helices may be formed by varying the power of the respective surface generally periodically radially outward from the optical axis of the lens and angularly about the optical axis of the lens.

[0060] The method may include operating a lathe to shape the surface of the lens. Alternatively or additionally, the method may include operating a lathe to shape the surface of a mold of the lens. Alternatively or additionally, the method may include operating a lathe to shape the surface of an insert of a mold for manufacturing the lens. Those skilled in the art will appreciate that the further the object shaped by the lathe is from the lens, the less well-defined the feature definition will be on the resulting lens. Thus, for example, shaping the surface of the lens using a lathe will achieve a more well-defined surface feature than shaping the surface of a mold of the lens using a lathe.

[0061] In embodiments of the present invention in which the lens is a contact lens or an intraocular lens, the first and second surface power maps may be formed by shaping the optical zones of the first and second surfaces. It will be appreciated that the optical zone of a mold or an insert of a mold refers to the portion of the mold corresponding to the optical zone of a contact lens manufactured using the mold or insert.

[0062] A lens (such as a contact lens) according to the present invention may be formed by a casting molding process, a rotational casting molding process, a lathe process, or a combination thereof. As understood by those skilled in the art, casting molding refers to molding a lens component by placing a lens-forming material between a female mold component having a concave lens component-forming surface and a male mold component having a convex lens component-forming surface.

[0063] In embodiments where the ophthalmic lens comprises a contact lens, the contact lens material, which is used as part of or as the entire contact lens, is optically transparent (although it may contain a dispositional tint). As understood in the art, the contact lens material can be a hydrogel material, a silicone hydrogel material, or a silicone elastomer material. In other words, the contact lenses of the present invention can comprise a hydrogel material, a silicone hydrogel material, or a silicone elastomer material, consist essentially of a hydrogel material, a silicone hydrogel material, or a silicone elastomer material, or consist of a hydrogel material, a silicone hydrogel material, or a silicone elastomer material. As understood in the field of contact lenses, a hydrogel is a material that holds water in equilibrium and does not contain silicon-containing chemicals. A silicone hydrogel is a hydrogel that contains silicon-containing chemicals. As used herein, the hydrogel material and the silicone hydrogel material have an equilibrium water content (EWC) of at least 10% to about 90% (wt / wt). The hydrogel material or the silicone hydrogel material can have an EWC of about 30% to about 70% (wt / wt). In contrast, the silicone elastomer material as used herein has a water content of about 0% to less than 10% (wt / wt). Generally, the silicone elastomer material used with the present method or device has a water content of from 0.1% to 3% (wt / wt). Alternatively, examples of the contact lenses of the present invention can be made of a rigid gas-permeable material, such as polymethyl methacrylate (PMMA), etc.

[0064] The method can comprise the step of forming a contact lens in a molding assembly that includes a first mold part and a second mold part assembled together. In the case of a hydrogel lens or a silicone hydrogel lens, the lens can be manufactured by polymerizing a hydrogel or silicone hydrogel lens formulation that contains a polymerization initiator formed in a lens-shaped cavity between the first mold part and the second mold part. For a silicone elastomer lens, the lens can be manufactured by curing, vulcanizing, or catalyzing (e.g., by hydroxylation), with a liquid silicone elastomer material located in the lens-shaped cavity formed between the first mold part and the second mold part. The surface of each mold part that forms the contact lens-shaped cavity can be convex, concave, flat, or a combination thereof. After the contact lens is formed, the two mold parts are separated such that the contact lens remains attached to the surface of one of the mold parts. As a result, the contact lens is provided on the surface of the first or second mold part. It may be desirable to place the lens part on the surface of the mold part that was not used to produce the first lens part, but additional steps may be required to achieve the desired alignment of the part with the mold part. Then, the lens can be removed from the mold part to which it is attached and further processed, such as by extraction and hydration, then inspected, and encapsulated and sterilized.

[0065] Figure 1Disclosed is a contact lens 10 according to an embodiment of the present invention. The contact lens 10 includes an optical zone 11 and a peripheral zone 13. The optical zone 11 includes the portion of the lens through which the wearer of the contact lens sees. The optical zone 11 forms a lens designed to provide vision correction to the wearer. The peripheral zone 13 surrounds the optical zone 11 and does not provide any vision correction to the wearer. The peripheral zone 13 can perform other functions. For example, the peripheral zone 13 can be used to help hold the contact lens on the wearer's eye. The peripheral zone 13 can include a ballast to maintain a predetermined orientation of the contact lens on the wearer's eye.

[0066] The two surfaces of the contact lens are shaped such that they vary across the optical zone 11 to form first and second surface power maps. The first and second surface powers Figure 1 combine to form a lens power map. Thus, the optical zone can be said to provide a first surface power map, a second surface power map, and a lens power map. Within the optical zone, the power map can include one or more different regions. Figure 1 The exemplary contact lens shown includes a central region 15, an outer region 17, and a transition region 19. The outer region 17 surrounds the transition region 19. The transition region 19 surrounds the central region 15. The central region 15 and the outer region 17 can provide different arrangements of lens power such that they provide different vision corrections. The transition region 19 can be used to provide a smooth transition between the central region 15 and the outer region 17. It will be appreciated that Figure 1 the contact lens illustrated is provided only as an example, and other contact lenses according to the present invention can include more or fewer regions. For example, a contact lens according to an embodiment of the present invention can omit the transition zone, or even can include only a single region across the entire optical zone 11. A contact lens according to an embodiment of the present invention can include additional regions, such as regions formed as concentric circles.

[0067] According to a first exemplary embodiment of the present invention, a contact lens for myopia control is provided. It will be appreciated that alternative embodiments can include intraocular lenses or spectacle lenses. The contact lens includes a first surface and a second surface. In this exemplary embodiment, the first surface includes the outer surface of the contact lens, and the second surface includes the inner surface of the contact lens. Those skilled in the art will appreciate that the outer surface is the convex surface of the contact lens adjacent to the wearer's eyelid, and the inner surface is the concave surface of the contact lens adjacent to the wearer's eye.

[0068] The first surface is shaped to form a first surface power map. In this exemplary embodiment, the first surface power map is formed only by a portion of the first surface. In this case, the portion of the first surface is defined by the optical zone of the contact lens and corresponds to the optical zone of the contact lens. Thus, the first surface power map can also be said to be provided by the variation of the first surface of the optical zone.

[0069] The optical zone of a contact lens can provide any vision modification of the lens. A contact lens according to an embodiment of the present invention may also include a surrounding peripheral zone that does not provide additional focusing or vision modification. In the case of such a contact lens, the peripheral zone may only be used to help maintain the position of the contact lens on the wearer's eye. Thus, those skilled in the art will understand that in such embodiments, the first surface power map is defined by the variation across the first surface of the optical zone of the lens. Similarly, the second surface power map is defined by the variation across the second surface of the optical zone. In these embodiments, the variation of the lens surface outside the optical zone (e.g., in the peripheral zone) does not affect the surface power map.

[0070] Those skilled in the art will understand that the first surface power map shows the modification to the overall contact lens power map provided by the shape of the surface. Thus, a contact lens having two surfaces (an inner surface and an outer surface) will include two surface power maps, the combination of which determines the overall contact lens power map.

[0071] Figure 2 The first surface power map 100 is shown. The first surface power map 100 forms a helix. The helix includes a plurality (in this example, 4) of arms 101. Each of the arms 101 includes one of a peak arm 101a and a trough arm 101b. It will be understood that the peak arm 101a is the arm that is positively offset from the average power of the surface power map (or the periodically varying region of the surface power map), and the trough arm 101b is the arm that is negatively offset from the average power of the surface power map (or the periodically varying region of the surface power map). The helix is formed by varying the power radially outward from the optical axis of the contact lens generally periodically and angularly about the optical axis of the contact lens. It will be understood that the optical axis of the contact lens is equivalent to the optical axis of the optical zone of the contact lens. The power varies between a first lens power and a second lens power. The first surface power map of this exemplary embodiment has a base lens power of -3.0D and an additional power of +3.0D. Thus, the first lens power is -3.0D and the second lens power is +0D. Those skilled in the art will understand that the specific values of the first lens power and second lens power (and thus the base lens power and additional power) provided are purely exemplary, and the actual values used in a given case will be determined by the needs of the intended wearer.

[0072] In this exemplary embodiment, the period of the radial variation is 1.2 mm, and the period of the angular variation is 90 degrees. However, it will be understood that in alternative embodiments, other periods of radial and / or angular variation may be used. The period of the radial variation need only be greater than 100 microns, and the period of the angular variation need only be greater than 6 degrees.

[0073] In this particular embodiment, the power varies smoothly across the first surface power map 100, being generally sinusoidal in both the radial and angular directions. Having the surface power map vary smoothly across the first surface power map facilitates manufacturing using a lathe for contact lenses or a device for manufacturing contact lenses (e.g., a mold or an insert for a mold). However, in alternative embodiments, the power may vary according to other waveforms. For example, the power may vary in the form of a square wave or a circular square wave in one or both of the radial and angular directions. Thus, in alternative embodiments, the power need not vary smoothly across the first surface power map.

[0074] In this exemplary embodiment, the positive and negative offset lengths of the sine curve are equal, such that the sine curve can be said to have a duty cycle of 50%. Alternative embodiments include variables having other duty cycles. Thus, in such embodiments, the positive offset may be a different length than the negative offset.

[0075] It will be appreciated that the width of the arms 101 of the helix is at least partially determined by the ratio of the period of the radial variation to the period of the angular variation. In this exemplary embodiment, each arm 101 of the helix is approximately 500 microns wide. It will be appreciated that alternative embodiments may incorporate arms 101 having different widths. It will also be appreciated that the width of the arm 101 is defined as its perpendicular width.

[0076] Similarly, in this exemplary embodiment, each of the periods of the radial and angular variations is generally constant across the first surface power map. However, in alternative embodiments, the period of at least one of the radial and angular variations may change according to one or both of the radial distance from the optical axis of the lens and the angular position around the optical axis of the lens.

[0077] In alternative embodiments, the period of the angular variation is less than 180°. Those skilled in the art will appreciate that the period of the angular variation determines the number of arms 101 on the helix. Thus, in such embodiments, the helix includes at least two arms. Thus, it will also be appreciated that certain values of the angular variation, particularly those that are unit fractions of 360 degrees, may be particularly advantageous as they allow for a surface power profile without angular discontinuities.

[0078] In this exemplary embodiment, each arm 101 of the helix twists through an angle of 270 degrees (or 0.75 revolutions). In alternative embodiments of the present invention, each arm 101 of the helix may twist through between a quarter revolution (90 degrees) and 40 revolutions.

[0079] In this particular embodiment, the first surface power map 100 includes a central region 103 and an outer region 105. The central region 103 closely surrounds the optical axis of the contact lens. The outer region 105 surrounds the central region 103. The power across the central region 103 does not vary periodically across the central region 103 and, for example, the power across the central region 103 may be substantially constant. The outer region 105 includes a spiral power profile and, as a result, angular and radial variations in power.

[0080] In an alternative embodiment of the present invention, the central region includes a spiral power profile and the outer region does not vary periodically across the outer region (e.g., the outer region may have a substantially constant lens power). In other alternative embodiments of the present invention, each arm 101 of the spiral extends from the center of the first surface power map to the periphery of the first surface power map. Thus, such embodiments do not include distinct central and outer regions.

[0081] In this exemplary embodiment, the central region 103 has a diameter of 2 mm, which corresponds to 25% of the 8 mm diameter of the power map. In this exemplary embodiment, the power map corresponds to the optical zone of the contact lens. Thus, the optical zone through which the wearer views provides Figure 2 the first surface power map 100 shown therein. The contact lens may additionally include a surrounding peripheral zone that does not provide additional focusing or vision modification and is only used to help maintain the position of the contact lens on the wearer's eye. In other embodiments, the diameter of the central region may be less than 25% of the diameter of the power map (or optical zone). However, it will be appreciated that in alternative embodiments of the present invention, the diameter of the central region 103 may take other values. Similarly, it will be appreciated that the ratio of the diameter of the central region 103 to the diameter of the power map may also take other values. For example, the diameter of the central region 103 may be less than 30% of the diameter of the power map (or optical zone).

[0082] In an embodiment, the central region 103 may be smaller than the smallest pupil size of the wearer of the contact lens. Such embodiments maintain effective myopia control even when the wearer's pupil constricts to its smallest size. If the central region 103 is larger than the smallest pupil size, then when the wearer's pupil constricts to its smallest size, only the central region 103 will be positioned across the wearer's entrance pupil. Since the power of the central region 103 does not vary with the spiral across the central region 103, the lens may not provide effective myopia control for any pupil size smaller than the central region 103. It will be appreciated that in an ophthalmic lens according to an embodiment of the present invention, the wearer's eye may move independently of the lens. Thus, when the central region is smaller than the wearer's smallest pupil size, nonetheless, such a lens may provide effective myopia control.

[0083] This exemplary embodiment further includes a transition region 107. The transition region 107 surrounds the central region 103. The outer region 105 surrounds the transition region 107. The degree of change of the transition region 107 provides a smooth transition between the central region 103 and the outer region 105. It will be appreciated that such a transition region 107 is not necessary, and thus alternative embodiments do not include the transition region 107. It will be understood that in this context, smooth is defined as smooth enough that the corresponding lens curvature can be reproduced by a lathe. In this exemplary embodiment, the transition region is approximately 300 microns wide. However, it will be appreciated that transition regions of other widths may also be used.

[0084] Those skilled in the art will appreciate that the second surface of the contact lens forms a second surface power map. The second surface power map is also provided by only a portion of the second surface, which also corresponds to the optical zone of the contact lens. The second surface power map 200( Figure 3 ) also varies angularly about the optical axis of the lens and radially outward from the optical axis of the lens periodically. Thus, the second surface power map 200 also includes a helix. As in the case of the first surface, the helix includes a plurality of arms 201 including peak arms 201a and trough arms 201b. In this exemplary embodiment, the periods of the radial and angular variations of the second surface power map 200 are the same as those of the first surface power map 100. However, those skilled in the art will appreciate that alternative embodiments may incorporate variations with different periods on the second surface power map 200 into one or both of those of the first surface power map 100. The period of the angular variation of the second surface power map 200 may be greater than 6 degrees. Similarly, in alternative embodiments, the period of the radial variation of the second surface power map 200 may be greater than 100 microns. In this exemplary embodiment, the second surface power map 200 also includes a central region 203, an outer region 205, and a transition region 207.

[0085] The helix formed by the second surface power map 200 twists in the opposite direction to the helix formed by the first surface power map 100. Thus, in this particular embodiment, the helices provided by the first surface power map 100 and the second surface power map 200 are the same but twist in opposite directions. The power map of the contact lens is determined by the superposition of the power maps of the first surface power map 100 and the second surface power map 200. Figure 4 Shows the overall lens power map of the contact lens of the first embodiment.

[0086] The superposition of two counter-rotating spirals formed by a first surface power map 100 and a second surface power map 200 produces a lens power map that approximates a pseudo bull's-eye pattern of alternating zones of annular rings. The lens power alternates generally between a first lens power and a second lens power in both the radial and angular directions. Since the power alternates angularly between the first lens power and the second lens power, the contact lens also provides a monotonic change in the ratio of the first lens power to the second lens power as the wearer's pupil constricts. Thus, the contact lens 300 also provides a more constant ratio of the lens power that provides myopic defocus to the lens power that provides far vision focus under variable light conditions.

[0087] Since both the first surface power map 100 and the second surface power map 200 include a center, a periphery, and a transition region, the overall power map of the contact lens 300 also includes a central region 303, an outer region 305, and a transition region 307.

[0088] Figure 5 Showing a contact lens according to a second embodiment of the present invention. The second embodiment is generally the same as the first embodiment, but the spiral provided by the second surface power map has been rotated 45 degrees out of phase. As can be seen from Figure 5 visible, the superposition of the first and second surface power maps including two counter-rotating spirals produces a pseudo bull's-eye power map similar to that of the second embodiment. Thus, regardless of the relative phase of the first and second spirals, the superposition of two counter-rotating spirals produces a pseudo bull's-eye lens power map. Again, the overall lens power map of the contact lens 400 includes a central region 403, an outer region 405, and a transition region 407.

[0089] Figure 7Disclosed is a spectacle lens 700 according to a third embodiment of the present invention. The spectacle lens includes first and second surfaces providing first and second surface diopter maps generally as described with respect to the first embodiment of the present invention. However, those skilled in the art will understand that the spectacle lens does not include an optical zone in the same sense as the contact lens of the first embodiment. Thus, in this case, the first and second surface diopter maps are provided by at least a portion of the spectacle lens, such as generally all of the spectacle lens. It will be understood that alternative embodiments of the present invention include spectacle lenses having surface diopter profiles generally as described with respect to the second embodiment of the present invention. The spectacle lens 700 includes a central region 715, an outer region 717, and a transition region 719. In this exemplary embodiment, the helix formed by the first and second surface diopter maps does not extend to the leftmost edge of the spectacle lens 700. Instead, the helix only extends to the dashed line 701. As the helix extends outward to the dashed line 701, the helix may decay in magnitude (e.g., linearly) from the boundary between the transition region 719 and the outer region 717. In other embodiments, the helix may have a generally constant magnitude across the outer region 717. In such embodiments, the spectacle lens 700 may further include a narrow blending region extending along the dashed line 701. It will further be understood that in other embodiments, the helix continues to extend outward to the edge of the spectacle lens 700. In this exemplary embodiment, the central region 715 (and the surrounding transition region 719 and outer region 717) is not located at the geometric center of the spectacle lens 700 and is said to be offset from the geometric center of the spectacle lens 700. Those skilled in the art will understand that such an offset can be used to place the central region in the portion of the spectacle lens 700 most commonly passed through by the wearer.

[0090] According to a fourth embodiment of the present invention, an intraocular lens is provided. The intraocular lens includes first and second surfaces providing first and second surface diopter maps generally as described with respect to the first embodiment of the present invention. It will be understood that alternative embodiments of the present invention include intraocular lenses having surface diopter profiles generally as described with respect to the second embodiment of the present invention.

[0091] Figure 6 Shown is a flowchart illustrating the steps of a method 500 for manufacturing a lens (e.g., a contact lens) for myopia control according to a fifth embodiment of the present invention.

[0092] The first step of the method 500, represented by element 501, includes operating a lathe to form the first surface of one of: a lens, a mold of the lens, or an insert of a mold for manufacturing the lens. The first surface is formed such that the first surface forms a first surface diopter map. The first surface diopter map includes a helix. The surface may be formed to vary generally periodically radially outward from and angularly about the optical axis of the contact lens.

[0093] The second step of method 500, represented by element 503, includes operating a lathe to form a second surface of a lens, mold, or insert. The second surface is formed to create a second surface power map. The second surface power map includes a helix. The second surface may be formed to vary generally periodically radially outward from the optical axis of the contact lens and angularly about the optical axis of the contact lens. The second surface is formed such that the helix formed by the first surface power map twists in a direction opposite to the helix formed by the second surface power map.

[0094] When the first and second surfaces are included on a mold for a lens or an insert for a mold for a lens, method 500 may include an optional third step, represented by element 505. The third step 505 includes manufacturing a lens using a mold for an insert for a mold for a lens.

[0095] Although the invention has been described and illustrated with reference to specific embodiments, those of ordinary skill in the art will understand that the invention is applicable to many different variations not specifically set forth herein. By way of example only, some possible variations will now be described.

[0096] In both the first and second embodiments, each of the surface power maps of the contact lens includes a central region having a generally constant power, an outer region incorporating a helical power profile, and a transition region providing a smooth transition between the central region and the outer region. However, some alternative embodiments do not incorporate a transition region. Further alternative embodiments do not incorporate distinct central and outer regions. Instead, in such embodiments, the helical profile extends from the center of each of the surface power maps to the radial periphery of the surface power maps.

[0097] In the first and second embodiments, the helix formed on the first surface power map twists in a counterclockwise direction, and the helix formed on the second surface power map twists in a clockwise direction. However, in alternative embodiments, the helix formed on the first surface power map twists in a clockwise direction, and the helix formed on the second surface power map twists in a counterclockwise direction.

[0098] In some embodiments of the present invention, the helix formed on one or both of the first and second surface power maps changes its direction of rotation at a predetermined radial distance from the optical axis of the lens. For example, the helix may rotate in a clockwise direction between the optical axis of the lens and the predetermined radial distance, and may rotate in a counterclockwise direction beyond the predetermined radial distance. The lens may incorporate more than one change in the direction of rotation of the helix. Thus, for example, the helix may change from clockwise rotation to counterclockwise rotation and then revert to clockwise rotation. Those skilled in the art will appreciate that the lens may incorporate any number of changes in the direction of rotation of the helix. It will also be appreciated that each of the changes in direction may occur at any selected radial distance from the optical axis of the lens. Thus, the power map may include annular rings that alternate between clockwise and counterclockwise rotating helices. In such embodiments, it may be that each reversely rotating helix changes its direction of rotation at the same radial distance from the optical axis of the lens.

[0099] In some embodiments, between regions of an ophthalmic lens having different directions of rotation, there may be regions where the power map does not vary as a helix. For example, the region may have a substantially constant power. For example, from the center of the lens to a first radial distance, the lens may vary as a clockwise rotating helix, followed by a region of substantially constant power, and then vary as a counterclockwise rotating helix. Thus, the power map may appear to include multiple annular rings, for example alternating between a helix and a substantially constant power, where the helix regions also alternate between clockwise and counterclockwise rotation.

[0100] Similarly, in some embodiments, the helix may be interrupted by one or more regions (such as rings) where the power map does not vary as a helix. Such regions may have a substantially constant power. Thus, for example, the power map may include annular rings that alternate between a helical power and a substantially constant power. In such embodiments, the helix may change its direction of rotation between each interruption, or it may continue its previous direction of rotation. Thus, the helix may maintain a constant direction of rotation across the lens, but may be interrupted by regions of substantially constant lens power.

[0101] Although embodiments of the present invention have been described above with respect to methods of manufacturing contact lenses, molds for contact lenses, or inserts for molds for contact lenses using a lathe, it will be appreciated that other manufacturing methods are possible. For example, the mold or insert may also be manufactured using additional manufacturing techniques, such as by 3D printing.

[0102] In the foregoing description, integers or elements having known, obvious or foreseeable equivalents are mentioned, and then such equivalents are incorporated herein as if individually set forth. Reference should be made to the claims for determining the true scope of the invention, which should be construed to cover any such equivalents. The reader will also understand that integers or features of the invention described as preferred, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Further, it should be understood that although such optional integers or features may be beneficial in some embodiments of the invention, they may not be desirable in other embodiments and may therefore be absent.

Claims

1. An ophthalmic lens for controlling myopia progression, the lens comprising: an outer surface, which is convex and is shaped to form a first surface power map, and an inner surface, which is concave and is shaped to form a second surface power map, wherein: the first surface power map includes a helix; the second surface power map includes a helix; and the helices provided by the first and second surface power maps twist in opposite directions.

2. The ophthalmic lens according to claim 1, wherein the lens is a contact lens or an eyeglass lens.

3. The ophthalmic lens according to claim 1 or 2, wherein the power varies smoothly across the first and second surface power maps.

4. The ophthalmic lens according to claim 3, wherein the power of the inner surface and the outer surface varies both radially and angularly as a circular square wave or a sine curve.

5. The ophthalmic lens according to claim 1 or 2, wherein each of the first and second surface power maps has a power that varies generally periodically radially outward from the optical axis of the lens and angularly about the optical axis of the lens.

6. The ophthalmic lens according to claim 5, wherein the period of the radial and angular variations is generally constant across the first and second surface power maps.

7. The ophthalmic lens according to claim 5, wherein the period of one or more of the radial and angular variations changes according to one or both of: the radial distance from the optical axis of the lens and the angular position about the optical axis of the lens.

8. The ophthalmic lens according to claim 5, wherein: the radial variation has a period greater than 100 microns; and the angular variation has a period greater than 6 degrees.

9. The ophthalmic lens according to claim 1 or 2, wherein each helix includes at least four arms.

10. The ophthalmic lens according to claim 1 or 2, wherein each arm of each helix twists at least half a turn.

11. The ophthalmic lens according to claim 1 or 2, wherein: the lens includes a central region and an outer region, the central region tightly surrounding the optical axis of the lens and the outer region surrounding the central region; the helix is formed in the outer region; and the helix does not extend into the central region.

12. The ophthalmic lens according to claim 1 or 2, wherein: the lens includes a central region and an outer region, the central region tightly surrounding the optical axis of the lens and the outer region surrounding the central region; the helix is formed within the central region; and the helix does not extend into the outer region.

13. The ophthalmic lens according to claim 11, wherein the central region has a diameter less than 50% of the diameter of the helix.

14. The ophthalmic lens according to claim 11, wherein: the lens includes a transition region, the transition region surrounding the central region and the outer region surrounding the transition region; and the power variation in the transition region provides a smooth transition between the central and outer regions.

15. The ophthalmic lens according to claim 1, wherein each helix comprises a plurality of arms, and each of the plurality of arms comprises a peak arm and a groove arm.

16. A method of manufacturing an ophthalmic lens, the method comprising: operating a lathe to form one of a convex surface and a concave surface of: a lens, a mold of the lens, or an insert of a mold for manufacturing the lens, such that: the convex surface forms a first surface power map; the concave surface forms a second surface power map; each of the first surface power map and the second surface power map comprises a helix; and the helixes formed by the first surface power map and the second surface power map are twisted in opposite directions.

Images