Myopia control contact lenses and related methods

Abstract

A contact lens (201) for use in preventing or slowing the onset or progression of myopia and related methods are disclosed. The lens (201) includes an optic zone (202) having a central region (205) with a first optical axis (219) and a curvature centered on the first optical axis (219) that provides a base power. The optic zone (202) also includes an annular region (203) surrounding the central region (205). The annular region (203) has at least one maximum add power meridian (203a) that provides a maximum add power and has a curvature centered on the first optical axis (219) at a first distance from the first optical axis (219). The annular region (203) provides an intermediate add power between zero diopter add power and maximum add power and has at least one intermediate add power meridian (203c) having a curvature centered at a distance from the first optical axis (219) that is different from the first distance.

Description

[Technical field]

[0001] The present disclosure relates to contact lenses used to prevent or slow the onset or progression of myopia. The present disclosure also relates to methods of making such lenses and methods of using such lenses. Additionally, the present disclosure relates to certain contact lenses and methods for providing improved visual contrast. [Background technology]

[0002] Myopia affects a significant number of people, including children and adults. A myopic eye focuses incident light from a distant object to a location in front of the retina. As a result, the light diverges toward the retina and is out of focus when it reaches the retina. Conventional lenses for correcting myopia (e.g., eyeglass lenses and contact lenses) cause incident light from a distant object to diverge before it reaches the eye, which shifts the location of the focus onto the retina. Decades ago, it was proposed that the progression of myopia in children and adolescents could be slowed or prevented by undercorrection, i.e., by bringing the focal point closer to the retina but not completely on the retina. However, this approach inevitably results in a decrease in distance visual acuity compared to that obtained with a lens that completely corrects myopia. Furthermore, the effectiveness of undercorrection in controlling the progression of myopia is now considered questionable. A more recent approach is to provide lenses that have both areas that provide complete correction of distance vision and areas that undercorrect, i.e., intentionally induce myopic defocus. It has been suggested that this approach can prevent or slow the onset or progression of myopia in children and adolescents while providing good distance visual acuity. The regions that provide full correction of distance vision are typically referred to as base power regions, and the regions that provide undercorrection or intentionally induce myopic defocus are typically referred to as add power regions or myopic defocus regions (where the power is more positive or less negative than the power (diopter) of the distance region).

[0003] The surface of the add power region (typically the anterior surface) has a radius of curvature that is smaller than the radius of curvature of the distance power region, thus providing a more positive or less negative optical power (diopter) to the eye. The add power region is designed to focus incoming parallel light (i.e., light from far away) into the eye in front of the retina (i.e., closer to the lens). The distance power region is designed to focus light to form an image on the retina (i.e., further from the lens).

[0004] Another type of contact lens that reduces the progression of myopia is the bifocal contact lens, available under the name MISIGHT (CooperVision, Inc.). Unlike bifocal or multifocal contact lenses that are designed to improve vision in presbyopic people, bifocal lenses are constructed with predetermined optical dimensions that provide the use of distance correction (i.e., base power) to view both distant and near objects. The treatment zone of the bifocal lens, which has an add power, provides myopic defocused images at both distant and near viewing distances.

[0005] Although these lenses have been found to be beneficial in preventing or slowing the onset or progression of myopia, the annular additional refractive power region may cause undesirable visual side effects. Light focused by the annular additional refractive power region in front of the retina diverges from the focal point to form a defocused ring on the retina. Thus, wearers of these lenses may see a ring or "halo" around the image formed on the retina, especially for small, bright objects such as street lamps or car headlights. Also, rather than using the eye's natural accommodation (i.e., the eye's natural ability to change focal length) to focus on nearby objects, the wearer may utilize the additional focal point in front of the retina resulting from the annular additional refractive power region. This, in turn, may result in the wearer unconsciously using the lens in the same manner as presbyopic corrective lenses are used, which is undesirable for young subjects.

[0006] A further lens has been developed that may be used to treat myopia and is designed to eliminate the halos observed around the focal distance image in the MISIGHT (CooperVision, Inc.) lens and other similar lenses mentioned above. In this lens, an annular region is configured to prevent an on-axis image from being formed in front of the retina, thereby preventing such an image from being used to prevent the eye from accommodating to a near target. Rather, a distant point source is imaged by the annular region into a ring-like focal line at the near add-power focal plane, resulting in a small spot size of light on the retina at the far focal plane without the surrounding "halo" effect.

[0007] The present disclosure provides improved lenses for use in young subjects that prevent or slow the progression of myopia. Summary of the Invention

[0008] The present disclosure provides, according to a first aspect, a contact lens for use in preventing or slowing the onset or progression of myopia. The lens comprises an optical zone. The optical zone has a central region, the central region having a first optical axis and a curvature providing a base power and centered on a center of curvature on the first optical axis. The optical zone also has an annular region surrounding the central region. The annular region has at least one maximum addition power meridian providing a maximum addition power and having a curvature centered on a center of curvature at a first distance from the first optical axis. The annular region has at least one intermediate addition power meridian providing an intermediate addition power between zero diopter addition power and the maximum addition power and having a curvature centered on a center of curvature at a distance different from the first optical axis from the first distance.

[0009] The present disclosure provides, according to a second aspect, a method of manufacturing a contact lens according to the first aspect. The method comprises forming a contact lens. The contact lens comprises a central region and an annular region, the central region having a base power and the annular region surrounding the central region. The annular region provides a maximum addition power and has at least one maximum addition power meridian having a curvature centered at a first distance from a first optical axis. The annular region also has at least one intermediate addition power meridian providing an intermediate addition power between zero diopter addition power and the maximum addition power and having a curvature centered at a distance different from the first optical axis from the first distance.

[0010] The present disclosure provides, according to a third aspect, a method of reducing the progression of myopia, comprising providing a multifocal ophthalmic lens according to the first aspect to a myopic person, the multifocal ophthalmic lens being capable of accommodating to various near distances.

[0011] Of course, it will be understood that features described in connection with one aspect of the present disclosure may be incorporated in other aspects of the present disclosure, for example a method of the present disclosure may incorporate features described with reference to an apparatus of the present disclosure, and vice versa.

[0012] Embodiments will now be described, by way of example only, with reference to the accompanying schematic drawings. [Brief description of the drawings]

[0013] [Figure 1A] FIG. 1A is a schematic plan view of a contact lens that employs a treatment zone that provides a myopic defocused image to reduce the progression of myopia.

[0014] [Figure 1B] FIG. 1B is a side view of the contact lens of FIG. 1A.

[0015] [Figure 2A] FIG. 2A is a ray diagram of the lens of FIGS. 1A and 1B.

[0016] [Figure 2B] FIG. 2B shows a light pattern at the near focal plane of the lens of FIG. 1A formed from a distant point source.

[0017] [Figure 2C] FIG. 2C shows a light pattern at the distal focal plane of the lens of FIG. 1A formed from a distant point source.

[0018] [Figure 3A] FIG. 3A is a plan view of another contact lens having non-coaxial optics for use in the prevention of myopia.

[0019] [Figure 3B] FIG. 3B is a side view of the contact lens of FIG. 3A.

[0020] [Figure 4A] FIG. 4A is a ray diagram of the lens of FIGS. 3A and 3B.

[0021] [Figure 4B] FIG. 4B shows the light pattern at the proximal focal plane of the lens of FIGS. 3A and 3B formed from a distant point source.

[0022] [Figure 4C] FIG. 4C shows a light pattern at the distal focal plane of the lens of FIGS. 3A and 3B formed from a distant point source.

[0023] [Figure 4D] Figure 4D is a partial ray diagram of the lens of Figures 3A and 3B, along with circles showing the radii of curvature of the central distance region (solid lines) and the annular additional region (dashed lines) of the contact lens.

[0024] [Figure 5A]FIG. 5A is a plan view of a lens according to one embodiment of the present disclosure, illustrating the arrangement of the variation of θ around the lens, showing the location of line AA along the maximum addition power meridian and line BB along the base power meridian.

[0025] [Figure 5B] FIG. 5B is a ray diagram of rays intersecting the lens of FIG. 5A along line AA, showing the optical axis of the central region and the center of curvature of the anterior surface along the meridian of maximum addition power.

[0026] [Figure 5C] FIG. 5C is a ray diagram of rays intersecting the lens of FIG. 5A along line BB, showing the optical axis of the central region and the center of curvature of the anterior surface along the base power meridian.

[0027] [Figure 6A] FIG. 6A is a vertical cross-sectional view of the lens of FIG. 5A, showing the focused rays at the maximum add power focal plane and the distal optical focal plane.

[0028] [Figure 6B] FIG. 6B shows the lens of FIG. 6A rotated circumferentially by 90 degrees, showing the light rays focused at the distal optical focal plane.

[0029] [Figure 7A] FIG. 7A is a ray diagram of the lens of FIG. 5A, showing rays intersecting the lens along line AA.

[0030] [Figure 7B] FIG. 7B is a ray diagram of the lens of FIG. 5A, showing rays intersecting the lens along line CC.

[0031] [Figure 7C] FIG. 7C is a ray diagram of the lens of FIG. 5A, showing a ray intersecting the lens along line BB.

[0032] [Figure 8] FIG. 8 is a plot showing the variation of the add power of the annular region of the lens of FIG. 5A with angle θ.

[0033] [Figure 9] FIG. 9 shows the light pattern at the distal focal plane of the lens of FIG. 5A formed from a distant point source.

[0034] [Figure 10] 10 is a partial ray diagram of a negative base power lens, along with circles showing the radii of curvature of the central distance zone (solid line) and the annular additional zone (dashed line) of the contact lens.

[0035] [Figure 11A] FIG. 11A is a plan view of a lens according to one embodiment of the present disclosure that includes two concentric annular regions.

[0036] [Figure 11B] FIG. 11B is a vertical cross-sectional view of the lens of FIG. 11A taken along line AA.

[0037] [Figure 12] FIG. 12 is a plot showing the variation of optical power with sagittal and with curvature for the lens shown in FIGS. 11A and 11B.

[0038] [Figure 13] FIG. 13 is a plan view of a lens according to one embodiment of the present disclosure showing lines AA, BB, CC, and DD at different θ values.

[0039] [Figure 14] FIG. 14 is a plot showing the variation of sagittal power with radial position for the lens shown in FIG.

[0040] [Figure 15] FIG. 15 is a two-dimensional plot showing modeling of the sagittal power of a lens according to one embodiment of the present disclosure.

[0041] [Figure 16] FIG. 16 is a plot showing Ps as a function of radial distance from the center of the lens for the lens modeled in FIG.

[0042] [Figure 17] FIG. 17 is a plan view of a lens having two annular regions according to one embodiment of the present disclosure.

[0043] [Figure 18] FIG. 18 is a plot showing the variation of optical power with curvature for the lens shown in FIG.

[0044] [Figure 19] FIG. 19 shows a lens according to one embodiment of the present disclosure on the eye.

[0045] [Figure 20A] FIG. 20A is a plot showing the stepwise variation of add power with θ for lenses according to several embodiments of the present disclosure.

[0046] [Figure 20B] FIG. 20B is a plot showing continuous sinusoidal variation of add power with θ for lenses according to several embodiments of the present disclosure.

[0047] [Figure 20C] FIG. 20C is a plot showing the sawtooth variation of add power with θ for lenses according to several embodiments of the present disclosure.

[0048] [Figure 21A] 21A shows a light pattern formed by light from a distant point source at the distal focal plane of a lens according to one embodiment of the present disclosure, the lens having a maximum add power every 180°.

[0049] [Figure 21B] 21B shows a light pattern formed by light from a distant point source at the distal focal plane of a lens according to one embodiment of the present disclosure, the lens having maximum add power every 60°.

[0050] [Figure 21C] 21C shows a light pattern formed by light from a distant point source at the distal focal plane of a lens according to one embodiment of the present disclosure, which has a single maximum power meridian (meridian zone) spanning 180° and a narrow intermediate power meridian (meridian zone) that forms a smooth boundary to the base power meridian (meridian zone).

[0051] [Figure 21D] 21D shows a light pattern formed by light from a distant point source at the distal focal plane of a lens according to one embodiment of the present disclosure, the lens having a maximum add power every 90°.

[0052] [Figure 22A] FIG. 22A is a plot showing the variation of optical power with θ for a lens according to one embodiment of the present disclosure, the lens having two meridians of maximum addition power with different optical powers.

[0053] [Figure 22B] FIG. 22B is a plot showing the variation of optical power with θ for a lens according to one embodiment of the present disclosure, the lens having a maximum addition power meridian with an asymmetric peak profile. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] According to a first aspect, the present disclosure provides a contact lens for use in preventing or slowing the onset or progression of myopia. The lens comprises an optical zone having a central region, the central region having a first optical axis and a curvature providing a base power and centered on a center of curvature on the first optical axis. The optical zone also has an annular region surrounding the central region. The annular region has at least one maximum add power meridian providing a maximum add power and having a curvature centered on a center of curvature at a first distance from the first optical axis, and at least one intermediate add power meridian providing an intermediate add power between zero diopter add power and the maximum add power and having a curvature centered on a center of curvature at a distance different from the first optical axis from the first distance.

[0055] As used herein, the term contact lens refers to an ophthalmic lens that can be placed on the front of the eye. It will be understood that such contact lenses provide clinically acceptable on-eye movement and do not bond to the human eye. The contact lens can be in the form of a corneal lens (e.g., a lens that rests on the cornea of ​​the eye). The contact lens can be a soft contact lens, such as a hydrogel contact lens or a silicone hydrogel contact lens.

[0056] A contact lens according to the present disclosure comprises an optical zone. The optical zone encompasses a portion of the lens having an optical function. The optical zone is configured to be positioned over the pupil of the eye in use. In the case of a contact lens according to the present disclosure, the optical zone includes a central region and an annular region surrounding the central region. The optical zone is surrounded by a peripheral zone. The peripheral zone is not part of the optical zone, but is located outside the optical zone and above the iris when the lens is worn, and provides a mechanical function, for example, increasing the size of the lens to make it easier to handle, providing ballast to prevent lens rotation, and / or providing a shape region that improves the comfort of the lens wearer. The peripheral zone may extend to the edge of the contact lens.

[0057] A contact lens according to an embodiment of the present disclosure may include a ballast to orient the lens when positioned on the wearer's eye. An embodiment of the present disclosure incorporating a ballast into a contact lens rotates to a predetermined angle of repose under the action of the wearer's eyelid when placed on the wearer's eye. For example, the ballast may be a wedge and the rotation may be caused by the action of the eyelid on the wedge. Ballasting contact lenses to orient them is well known in the art. For example, toric contact lenses are ballasted to orient the lens so that the orthogonal cylindrical correction provided by the lens is precisely aligned with the astigmatism of the wearer's eye. The contact lenses of the present disclosure may provide a particular benefit to the wearer in a given orientation. For example, a contact lens may provide a particular benefit to the wearer when the meridian of maximum addition power is in a particular direction.

[0058] The contact lens may be substantially circular in shape and may have a diameter of about 4 mm to about 20 mm. The optic zone may be substantially circular in shape and may have a diameter of about 2 mm to about 10 mm. In some embodiments, the contact lens has a diameter of 13 mm to 15 mm and the optic zone has a diameter of 7 mm to 9 mm.

[0059] The first optical axis may be along the centerline of the lens. The central region may focus (converge) light from a distant point object on the first optical axis to a spot on the first optical axis at the distal focal plane. As used herein, the term surface does not refer to a physical surface, but rather to a surface that can be drawn through a point where light from a distant object is focused. Such a surface is also called an image surface (which may be curved) or an image shell. The eye focuses light onto a curved retina. In a perfectly focused eye, the curvature of the image shell matches the curvature of the retina. Thus, the eye does not focus light onto a flat mathematical plane. Nevertheless, in the art, the curved surface of the retina is commonly referred to as a (planar) surface.

[0060] Light rays from a distant point source passing through at least one maximum addition power meridian may be focused away from the first optical axis on the maximum addition power focal plane. Light rays passing through the central region form an on-axis blur circle on the maximum addition power focal plane. Light rays from a distant point source passing through at least one maximum addition power annular region may be focused outside the blur circle.

[0061] The central region of the lens has a base power, the annular region of the lens has an add power, and the net near power of the annular region is the sum of the base power and the add power.

[0062] The base power of the lens may be positive and the at least one maximum addition power area may have a power that is more positive than the base power. In this case, the maximum addition power focal plane is closer to the lens than the distal focal plane. An on-axis image will not be formed by the light passing through the at least one maximum addition power meridian. The lens wearer must therefore use the natural accommodation of his or her eye to focus on nearby objects. It may be the case that the light rays focused by the at least one maximum addition power meridian do not intersect the first optical axis of the contact lens at all or do not intersect until after passing through the maximum addition power focal plane.

[0063] The base power of the lens may be negative and at least one maximum addition power area may have a power that is less negative than the power of the base power area, or the addition power area may have a positive power. Considering a lens positioned on the cornea, if the power of the maximum addition power area is less negative than the base power, the maximum addition power focal plane will be further in front of the eye than the distal focal plane. Considering a lens not positioned on the cornea, if the power of the maximum addition power area is positive, the maximum addition power focal plane will be on the opposite side of the lens (on the image side) from the distal focal plane (which will be the virtual focal plane on the object side of the lens), and if the power of the maximum addition power area is negative (but less negative than the base power), the virtual maximum addition power focal plane will be further from the lens than the virtual distal focal plane.

[0064] Light rays from a distant point source passing through at least one intermediate addition power annular meridian can be focused on the intermediate addition power focal plane. In the case of a lens having a positive base power and at least one intermediate addition power meridian with a power more positive than the base power, the intermediate addition power focal plane will be closer to the lens than the distal focal plane, but farther from the lens than the maximum addition power focal plane. Also, no on-axis image will be formed by the light passing through the at least one intermediate addition power meridian. It may be the case that the light rays focused by the at least one intermediate addition power meridian do not intersect the first optical axis of the contact lens at all, or do not do so until after passing through the intermediate and maximum addition power focal planes. Considering a lens positioned on the cornea, if the lens has a negative base power and at least one intermediate addition power region has a negative power less than the base power, the intermediate addition power focal plane will be closer to the lens than the distal focal plane, but farther than the maximum addition power focal plane. Considering a lens not positioned on the cornea, if the lens has a negative base power and at least one intermediate addition power region has a negative power less than the base power, the virtual addition power focal plane will be farther from the lens than the virtual distal focal plane, but closer than the virtual maximum addition power focal plane.

[0065] In the case of a lens having a positive base power, the at least one maximum addition power region will have a curvature greater than the curvature that provides the base power. In this case, the radius of curvature of the at least one maximum addition power meridian will be smaller than the radius of curvature of the central region. The center of curvature of the at least one maximum addition power meridian will be closer to the lens than the center of curvature of the central region. In the case of a lens having a negative base power, the at least one maximum addition power region may have a curvature less than the curvature that provides the base power. In this case, the radius of curvature of the at least one maximum addition power meridian will be greater than the radius of curvature of the central region.

[0066] The at least one intermediate addition power meridian may have a curvature that is between the curvature of the at least one maximum addition power region and the curvature of the central region. In this case, the radius of curvature of the at least one intermediate meridian will be smaller than that of the central region and larger than that of the at least one maximum addition power meridian. The center of curvature of the at least one intermediate addition power meridian will be closer to the lens than the center of curvature of the central region, but farther from the lens than the center of curvature of the at least one maximum addition power meridian.

[0067] Light rays from a distant point source passing through the annular region do not form a single focused image on the front focal plane of the retina. As a result of the varying additional refractive power around the circumference of the annular region (circumferentially), light rays from a distant point source passing through the annular region form a focused annular waveform. The waveform varies in three dimensions. Thus, the distance from the lens to the local focal point of the waveform varies around the axis of the lens. This causes the defocus to vary around the axis of the lens. When the lens is provided on the eye, different parts of the retina will be exposed to different amounts of defocus as a result of the varying additional refractive power of the annular region. Lenses that provide different amounts of defocus across the retina, especially defocus that varies periodically, may be more effective at slowing the growth of myopia than lenses with a constant myopic defocus.

[0068] The central region may focus light from a distant point object to a spot on the first optical axis at the distal focal plane. At least one maximum add power meridian and at least one intermediate add power meridian may direct light from the distant point object toward the spot. Light from a distant point object passing through the annular region may produce different levels of blurring at the distal focal plane as a result of the various (varying) add powers of the annular region. Light from a distant point source passing through the annular region may produce a meridional varying blurring pattern, which pattern depends on the arrangement of the multiple add power meridians, including at least one maximum add power meridian and at least one intermediate add power meridian. The annular region may limit the spread of off-axis light at the distal focal plane, for example by acting as an optical beam stop. This may improve the optical contrast of the image produced by the lens.

[0069] By reducing the spread of light at the distal focal plane, it is possible to improve the visual contrast observed by the lens wearer compared to lens designs such as that shown in Figure 1. Thus, the lenses and methods of the present invention can achieve a desired slowing of myopia progression while enhancing image contrast and image quality compared to existing contact lenses suitable for reducing myopia progression.

[0070] The annular region may further have at least one base power meridian, which provides the base power and has a curvature about the center of curvature of the central region. Alternatively, the add power of the annular region may vary between an intermediate add power and a maximum add power (i.e., there may be no base power meridian). The add power of the annular region may be more positive or less negative than the base power for all meridians.

[0071] At least one base power meridian can focus light from a distant point object to a spot on the first optical axis of the distal surface, which can coincide with a spot formed by light passing through the central region.

[0072] The (respective) curvatures providing the base power, maximum add power and intermediate add power may be the curvatures of the front surface of the lens. The (respective) curvatures providing the base power, maximum add power and intermediate add power may be the curvatures of the back surface of the lens. The (respective) curvatures providing the base power, maximum add power and intermediate add power may be the curvatures of the front and back surfaces of the lens that provide a combined effect.

[0073] The power of a lens may be defined as a sagittal-based or slope-based power. Slope-based power Ps is a function of the first derivative of the wavefront and varies with the slope of the wavefront. The annular region of the lens may be tilted relative to the central region. Since the sagittal power is a function of the slope of the lens surface, the tilt of the annular region relative to the central region results in a slope path of the sagittal power that starts more negative than the power at the inner edge of the annular region and increases with increasing radius to a less negative power at the outer edge of the annular region.

[0074] The annular region may be radially tilted with respect to the central region by different amounts at different meridians to match the sagittal power at the midpoint of the annular region at each meridian to the power the central region would have if extended to that midpoint. The lens may have a sagittal power at the midpoint of the annular region at at least one maximum addition meridian that matches the power the central region would have if extended to that midpoint. The lens may have a sagittal power at the midpoint of the annular region at at least one intermediate addition meridian that matches the power the central region would have if extended to that midpoint.

[0075] The annular region may include a periodic arrangement of maximum addition power meridians separated by intermediate addition power meridians. The addition power of the annular region may vary continuously between the maximum addition power meridian and the intermediate addition power meridian. The addition power of the annular region may be more positive or less negative than the base power for all meridians. The annular region may include a repeating periodic arrangement of maximum addition power meridians, intermediate addition power meridians, and base power meridians. The addition power of the annular region may vary continuously between the maximum addition power meridian, intermediate addition power meridian, and base power meridian. The position along the circumference of the lens may be defined by an angle θ between 0° and 360°, with a line along which θ=180° lies along the diameter of the lens. The annular region may include maximum addition power meridians that coincide with θ=0° and θ=180°. The annular region may include maximum addition power meridians that coincide with θ=0°, 90°, 180°, and 270°, or any other angle. The annular region may include a maximum addition power meridian every 10°, every 20°, or every 30° along the circumference of the lens. Alternatively, the annular region may include a non-periodic arrangement of multiple maximum addition power meridians along the circumference of the lens. If multiple maximum addition power meridians are present, they may have the same or different powers. If multiple maximum addition power meridians are present, they may be arranged at irregular intervals along the circumference of the annular region. Each of the at least one maximum addition power meridian may have a symmetric or asymmetric power profile. The power profile of the annular region may be symmetric or asymmetric between the meridians of maximum addition power.

[0076] The refractive power of the annular region may vary sinusoidally along the circumference of the annular region. The refractive power of the annular region may vary stepwise along the circumference of the annular region. The refractive power of the annular region may vary triangularly or sawtooth-like along the circumference of the annular region. The refractive power of the annular region may vary between the power of at least one maximum addition power meridian and the base power, or between the power of at least one maximum addition power meridian and the power of at least one intermediate addition power meridian. The period of variation may be, for example, 180°, 90°, 45° or 30°.

[0077] The central region may be substantially circular in shape and may have a diameter of about 2 mm to about 9 mm, preferably 2 to 7 mm. The central region may be substantially elliptical in shape. The annular region may extend radially outward from the periphery of the central region between about 0.1 mm to about 4 mm, preferably between about 0.5 mm to about 1.5 mm. For example, the radial width of the annular region may be between about 0.1 mm to about 4 mm, preferably between about 0.5 mm to about 1.5 mm. The periphery of the central region may define a boundary between the central region and the annular region, such that the annular region may be adjacent to the central region.

[0078] The annular region may be adjacent to the central region. A blending region may be provided between the central region and the annular region. The blending region should not substantially affect the optical system provided by the central region and the annular region, and may have a radial width of 0.05 mm or less, although in some embodiments it may be as wide as 0.2 mm, or as wide as 0.5 mm.

[0079] The central region has a base power, which in the context of this disclosure is defined as the average absolute power of the central region. Any base power meridian will also have a base power. The base power corresponds to the labeling power of the contact lens as provided on the contact lens package (although in practice they may not have the same value). The lens powers given herein are therefore nominal powers. These values ​​may differ from the lens power values ​​obtained by direct measurement of the lens, but reflect the lens powers used to provide the required prescription power when used in ophthalmic treatment.

[0080] For lenses used to treat myopia, the base power is negative or near zero, with the central region correcting distance vision. The base power can be between 0.5 diopters (D) and -15.0 diopters. The base power can be between -0.25D and -15.0D.

[0081] The maximum addition power is non-zero, i.e., each of the at least one maximum addition meridian has a lens power greater (i.e., more positive or less negative) than the base power of the central region. The power of the maximum addition meridian can be described as the maximum addition power, which is the difference between the base power and the power of the maximum addition meridian. The maximum addition power can be between about +0.5 and about +20.0D, preferably about +0.5 and about +10.0D. In the case of a lens with a positive base power, the power of each of the at least one maximum addition meridian can be more positive than the base power. In the case of a lens having a negative base power, the power of each of the at least one maximum addition power meridian may be less negative than the base power, or the power of each of the at least one maximum addition power meridian may be positive. The net power of the annular area at the maximum addition power meridian is the sum of the base power and the maximum addition power.

[0082] Each of the at least one intermediate addition meridian may have a lens power that is greater (i.e. more positive or less negative) than the base power of the central region. The power of the intermediate addition meridian may be described as the intermediate addition power, which is the difference between the base power and the power of the intermediate addition meridian. The intermediate addition power may be less than the maximum addition power and may be between about +0.1 and about +10.0D, preferably about +0.1 and about +3.0D. In the case of a lens with a positive base power, the power of each of the at least one intermediate addition meridian may be more positive than the base power. In the case of a lens with a negative base power, the power of each of the at least one intermediate addition meridian may be less negative than the base power, or the power of each of the at least one intermediate addition meridian may be positive. The net power of the annular region at the intermediate addition meridian is the sum of the base power and the intermediate addition power.

[0083] The lens may include at least two concentric annular regions, each having at least one maximum addition power meridian providing a maximum addition power and having a curvature centered at a first distance from the first optical axis, and at least one intermediate addition power meridian providing an intermediate addition power between zero diopter addition power and the maximum addition power and having a curvature centered at a distance different from the first optical axis from the first optical axis.

[0084] Each of the annular regions may be an annular region incorporating any of the features described above. The maximum addition power meridian of each annular region may be at the same θ value along the circumference of the annular region, and each of the intermediate addition power meridians may also be at the same θ value along the circumference of the annular region. Alternatively, the maximum addition power meridian of each of the annular regions may be at a different θ value along the circumference. The maximum addition power meridian of each of the annular regions may have the same maximum addition power. Each of the annular regions may have the same intermediate addition power. Alternatively, the maximum addition power meridians of each of the annular regions may be different. Each annular region may have multiple maximum addition power meridians, each of which may have the same or different powers. The intermediate addition powers of each annular region may be different.

[0085] Preferably, the annular region or regions do not contain lenslets (lenslets on the surface of a contact lens that are smaller in diameter than the diameter of the optic zone of the contact lens), i.e., the annular region or regions are lenslet free. The additional optical power of the annular region may be provided by a continuous lens surface, which may provide a smoothly varying additional optical power.

[0086] The contact lens may be a toric contact lens, for example, a toric contact lens may include an optical zone shaped to correct a person's astigmatism.

[0087] The contact lens may comprise an elastomeric material, a silicone elastomer material, a hydrogel material, or a silicone hydrogel material, or a combination thereof. As understood in the field of contact lenses, a hydrogel is a material that holds water in equilibrium and does not contain a silicone-containing compound. A silicone hydrogel is a hydrogel that includes a silicone-containing compound. As described in the context of this disclosure, hydrogel and silicone hydrogel materials have an equilibrium water content (EWC) of at least 10% to about 90% (wt / wt). In some embodiments, hydrogel or silicone hydrogel materials have an EWC of about 30% to about 70% (wt / wt). In comparison, as described in the context of this disclosure, silicone elastomer materials have a water content of about 0% to less than 10% (wt / wt). Typically, the silicone elastomer materials used in the present method or device have a water content of 0.1% to 3% (wt / wt).Examples of suitable lens formulations (compositions) include those having the following United States Adequate Names (USAN): methafilcon A, ocufilcon A, ocufilcon B, ocufilcon C, ocufilcon D, omafilcon A, omafilcon B, comfilcon A, enfilcon A, stenfilcon A, fanfilcon A, etafilcon A, senofilcon B, senofilcon C, senofilcon D ... senofilcon A, senofilcon B, senofilcon C, narafilcon A, narafilcon B, balafilcon A, samfilcon A, lotrafilcon A, lotrafilcon B, somofilcon A, riofilcon A, delefilcon A, verofilcon A, kalifilcon A, and the like.

[0088] Alternatively, the lens may comprise, consist essentially of, or consist of a silicone elastomer material. For example, the lens may comprise, consist essentially of, or consist of a silicone elastomer material having a Shore A hardness of 3 to 50. Shore A hardness may be determined using conventional methods (e.g., using method DIN 53505) as understood by those skilled in the art. Other silicone elastomer materials may be obtained, for example, from NuSil Technology or Dow Chemical Company.

[0089] By way of example, the lens may comprise a hydrogel contact lens or a silicone hydrogel contact lens having a lens diameter between 13 mm and 15 mm. The optic zone of the lens may have a diameter between 7 mm and 9 mm. The annular region of the optic zone may have a maximum addition power meridian with a maximum addition power between +2D and +20D. The annular region of the optic zone may have an intermediate addition power meridian with an intermediate addition power between +1D and +10D.

[0090] According to a second aspect, the present disclosure provides a method of manufacturing a lens. The method may comprise forming a contact lens with a central region and an annular region, the central region having a base power and the annular region surrounding the central region. The annular region has at least one maximum add power meridian providing a maximum add power and having a curvature centered at a first distance from a first optical axis. The annular region also has at least one intermediate add power meridian providing an intermediate add power between zero diopter add power and the maximum add power and having a curvature centered at a distance different from the first optical axis from the first distance.

[0091] The lens may include any of the features previously described.

[0092] The method of manufacturing may include forming a female member having a concave lens forming surface and a male member having a convex lens forming surface. The method may include filling a gap between the female member and the male member with a bulk lens material. The method may further include curing the bulk lens material to form a lens.

[0093] The contact lens may be a molded contact lens. The lens may be formed by a cast molding process, a spin casting process, or a lathing process, or a combination thereof. As understood by those skilled in the art, cast molding refers to a process of forming a lens by placing a lens molding material between a female mold member having a concave lens member forming surface and a male mold member having a convex lens member forming surface.

[0094] In a third aspect of the present disclosure, a method of using the contact lenses described herein is also provided. The method may be effective in reducing the progression of refractive errors, such as reducing (alleviating) the progression of myopia. When the lenses are used to reduce the progression of myopia, the method comprises providing the contact lenses to a person whose eyes can accommodate to various near distances (e.g., in a range of about 15 cm to about 40 cm). Some embodiments of the method comprise providing the ophthalmic lenses to a person who is about 5 years old to about 25 years old. The providing may be performed by an ophthalmic professional, such as an optician or an optometrist. Alternatively, the providing may be performed by a lens distributor who arranges for the ophthalmic lenses to be delivered to the lens wearer.

[0095] FIG. 1A shows a schematic plan view of a lens for use in slowing the progression of myopia (e.g., myopia correction). Lens 1 comprises an optical zone 2, which generally covers the pupil, and a peripheral zone 4, which is located above the iris. The peripheral zone 4 provides mechanical functions, including increasing the size of the lens to make it easier to handle, providing ballast to prevent rotation of the lens 1, and providing a geometric region that improves comfort for the wearer of lens 1. The optical zone 2 provides the optical functions of lens 1, which includes an annular region 3 and a central region 5. Lens 1 has a positive base power, and the radius of curvature of the anterior surface of annular region 3 is smaller than the radius of curvature of the anterior surface of central region 5. (This is illustrated in exaggerated schematic form in the ray diagram of FIG. 1B and the corresponding FIG. 2A.) Thus, annular region 3 has a greater refractive power than the base power of central region 5. The focal point 11 of the annular region 3 is on the proximal focal plane 13, and the focal point 15 of the central region 5 is on the distal focal plane 17, which is further away from the rear surface of the lens 1. The focal points 11 of the annular region 3 and the focal points 15 of the central region 5 share a common optical axis 19. As shown in FIG. 2C, for a point source at infinity, the light rays focused by the central region 5 form a focused image 23 at the distal focal plane 17. The light rays focused by the central region 5 also generate an unfocused blur spot 27 at the proximal focal plane 13.

[0096] 2B, the light rays focused by the annular region 3 form a focused image 21 at the proximal focal plane 13. The light rays focused by the annular region 3 diverge after the proximal focal plane 13, and the diverging light rays generate an unfocused annular (ring-shaped) image 25 at the distal focal plane 17. As previously mentioned, the unfocused annular image 25 can result in the wearer of the lens 1 seeing a "halo" around the focused distant image.

[0097] FIG. 3A shows a schematic diagram of another known lens 101 used in the treatment of myopia, which is designed to eliminate halos observed around focal distance images. Similar to lens 1 shown in FIGS. 1A and 1B, lens 101 comprises an optical zone 102 and a peripheral zone 104 surrounding optical zone 102. Optical zone 102 includes a central region 105 and an annular region 103 surrounding central region 105. As shown in FIG. 3B and the corresponding ray diagrams in FIGS. 4A and 4D, this lens 101 is a positive base power lens, where the anterior surface of annular region 103 has a greater curvature than the anterior surface of central region 105, thus providing a greater refractive power than the base power of central region 105. As shown in FIG. 4D, the anterior surface of central region 105 defines a portion of the surface of a sphere of greater radius 109. The anterior surface of annular region 103 defines a curved annular surface of smaller radius 106.

[0098] At the distal focal plane 117, the light rays passing through the central region 105 are focused (converged). The annular region 103 acts as an optical beam stop, which results in a small spot size 133 of light at the distal focal plane 117, as shown in FIG. 4C.

[0099] No single image is formed in the near focal plane 113. As shown in FIG. 4B, in the near focal plane 113, for a point source at infinity, the light rays passing through the central region 105 generate a blur circle 128, similar to the lenses of FIGS. 1A-1B and 2A-2B. On the other hand, the light rays from a distant point source passing through the annular region 103 generate a focused ring 122, which surrounds the blur circle 128, as shown in FIG. 4B. FIG. 4B shows the light pattern generated for a distant point source. In contrast to the lens 1 of FIG. 1, the lens 101 of FIG. 3 and FIG. 4 does not generate a single image or an on-axis image in the near focal plane 113, which could be used to avoid the need for the eye to adapt to near objects. For a distant extended object, the focused image formed at the near focal plane 113 is the convolution of (i) the focused image of the extended object that would be obtained with a conventional lens having the refractive power of the annular region 103 and (ii) an optical transfer function that represents the optical effect of the annular region 103.

[0100] In contrast to the lenses of FIGS. 1 and 2, no annular or “halo” effect occurs at the distal focal plane 117 .

[0101] FIG. 5A shows a schematic plan view of a lens according to an embodiment of the present disclosure. The position along the circumference of the lens can be indicated by an angle θ, which varies between 0° and 360°. In this example, line AA lies along θ=0° and line BB lies along θ=90°. FIG. 5B shows a schematic partial ray diagram of a ray intersecting the lens along line AA. FIG. 5C shows a schematic partial ray diagram of a ray intersecting the lens along line BB. Similar to lenses 1 and 101 shown in FIGS. 1A, 1B, 3A and 3B, lens 201 comprises an optic zone 202 and a peripheral zone 204 surrounding optic zone 202. Optical zone 202 includes a central region 205 and an annular region 203 surrounding central region 205. Central region 205 has a base power determined at least in part by the curvature of the anterior surface. Lens 205 has a positive base power.

[0102] The curvature of the annular region 203's front surface is different at different points (positions) along the circumference. This results in an annular region 203's additional power varying in the circumferential direction. The annular region 203's additional power varies in an oscillatory manner along the circumference between a maximum value (shown in FIG. 5B) and zero additional power (shown in FIG. 5C). At the maximum, the additional power of the annular region 203a is comparable to the additional power of the annular region shown for the lens of FIG. 3A, and at zero power, the additional power of the annular region 203b is equivalent to the base power of the central region 205. For the lens 201 shown in FIG. 5A, the additional power of the annular region 203 is maximum along the line AA (θ=0) and the additional power is 0D (diopters) along the line BB (θ=90° or 270°). That is, the additional power varies with a period of 180°. Between the lines AA and BB, the additional power has intermediate values.

[0103] The optical axis of the central region 205 is indicated by line 219 in Figures 5B and 5C. The center of curvature, indicated by "X", of the front surface of the central region 205 lies on said optical axis 219. The annular region 203 has a maximum addition power meridian 203a along line AA and a base power meridian 203b along line BB. The front surface of the maximum addition power meridian 203a provides the maximum addition power and has a curvature centered on a center of curvature indicated by X'. The center of curvature X' is at a first distance (indicated by line 220) from the first optical axis. The front surface of the base power meridian 203b along line BB provides the base power and has a curvature centered on the same center of curvature A as the central region 205.

[0104] Figure 6A shows a vertical cross section through lens 201 along line AA (i.e., along the meridian of maximum addition power 203a) according to an exemplary embodiment of the present disclosure. Figure 6B shows the same lens rotated 90° circumferentially, with the cross section along line BB (i.e., along the meridian of maximum addition power 203b).

[0105] Figure 7A shows a ray diagram of light rays intersecting lens 201 of Figure 5A along line AA, along which the add power of annular region 203a is greatest and the anterior surface of annular region 203a has a greater curvature than the anterior surface of central region 205, thus providing greater power than the base power of central region 205. The anterior surface of central region 205 defines a portion of the surface of a sphere of a first radius, in a manner similar to the lens shown in Figure 4D, and the anterior surface of annular region 203a defines a curved toric surface of a smaller radius of curvature.

[0106] Light rays that intersect the lens 201 along line AA and pass through the central region 205 are focused at the distal focal plane 217, as shown in Figures 6A, 6B and 7A-7C. At the maximum add power focal plane 230a, light rays from an infinitely distant point source that intersects the lens 201 along line AA and passes through the central region 205 will not form a focal point, while light rays from a distant point source that intersects the lens 201 along line AA and passes through the maximum add power annular region 203a will be focused away from the optical axis 219 of the central region.

[0107] 7C shows a ray diagram of rays intersecting the lens 201 along line BB. Along this line, the add power of the annular region 203b is zero. The front surface of the annular region 203b has the same radial curvature as the front surface of the central region 205. The rays intersecting the lens 201 along line BB and passing through the central region 205 are focused (converged) at the distal focal plane 217, as shown in FIGS. 6A, 6B and 7A-7C. The rays intersecting the lens 201 along line BB and passing through the zero add power annular region 203b are also focused (converged) at the distal focal plane 217.

[0108] 7B shows a ray diagram of light rays intersecting lens 201 along line CC, a line along θ=45°. Along this line, the additional refractive power of annular region 203c is intermediate between the additional refractive power of annular region 203a along line AA and the additional refractive power of annular region 203b along line BB. The anterior surface of annular region 203c defines a curved, annular surface with a smaller radius of curvature than annular region 203b, but a larger radius of curvature than annular region 203a. Light rays intersecting lens 201 along line CC and passing through central region 205 are focused (converged) at distal focal plane 217. At the intermediate addition power focal plane 230c, a ray from an infinitely distant point source intersecting the lens 201 along the line CC and passing through the central region 205 will not form a focus, while a ray from a distant point source intersecting the lens 201 along the line CC and passing through the intermediate power annular region 203c will be focused (converged). The intermediate focal plane 230c is closer to the lens 201 than the maximum addition power focal plane 230a. Figure 8 shows the variation of the addition power with θ for the annular region 203 of the lens 201 shown in Figures 5A-5C, 6A and 6B, and 7A-7C. For the lens 201 shown in Figures 5A-7C, the addition power is determined, at least in part, by the curvature of the front surface of the annular region 203. The add power is defined relative to the base power of the central region 205, so that zero add power means that the radial curvature of the annular region 203 anterior surface coincides with the curvature of the central region 205. For the lens 201 shown in Figures 5A to 7C, the radial curvature of the annular region 203 anterior surface, i.e. the add power of the annular region 203, varies continuously in an oscillatory manner with the meridian angle θ(0).

[0109] Light rays from a distant point source intersecting the lens 201 through the annular region 203 will not form a single image in front of the distal focal plane 217, but will generate a focused annular waveform with a defocus away from and varying by an angle θ about the central region's optical axis 219. At the distal focal plane 217, a meridional varying blur pattern 250 is generated by light rays from a distant point source intersecting the lens 201 through the annular region 203, as shown in FIG. 9. The blur pattern 250 surrounds a focal spot 251 generated by light rays passing through the central region 205. The blur is maximum along the line AA, which coincides with the maximum added power meridian 203a.

[0110] Thus, considering the annulus as a whole and moving around the meridian, light rays from a distant point source intersecting the lens 201 and passing through the annular region form a looping focal line that goes from the maximum add focal plane at 0° (12 o'clock) (where the focal line is closest to the front of the eye) towards the retina, to the intermediate add focal plane at 45°, to the minimum add focal plane at 90° (3 o'clock, where the focal line is closest to the retina), and then back towards the front of the eye again, through the intermediate add focal plane at 135°, to the maximum add at 180° (6 o'clock). The cycle repeats between 180° and 360°. The loop is symmetrical about lines AA and BB. Light rays from an infinitely distant point source intersecting the lens and passing through the central region are focused at the distal focal plane.

[0111] The aforementioned lenses have a positive base power. In another embodiment of the present disclosure, the base power of the lens 701 is negative. FIG. 10 shows a partial ray diagram of a lens 701 with a negative base power, for a section through the meridian of maximum addition power. The central region 705 of the lens 701, shown by the solid circle in FIG. 10, has a negative base power, and the annular region 703, shown by the dashed and dotted circle, has a smaller negative power. The central region 705 of the lens 701 has a larger curvature and a smaller radius of curvature than the annular region 703. The center of curvature of the central region 705 lies on the optical axis 719. The center of curvature of the annular region 703 is offset from the optical axis 719 of the central region. The virtual focal point of the light rays passing through the central region lies on the virtual distal focal plane 717. At the imaginary maximum addition power focal plane, light rays 730 from a distant point source passing through the annular region 703 form an imaginary focused ring.

[0112] The refractive power of a lens according to embodiments of the present disclosure may be defined as (i) a curvature-based refractive power, Pc, or (ii) a sagittal-based (or slope-based) refractive power, Ps.

[0113] For a given wavefront W, at a radial distance r (pupil radius) from a line perpendicular to the center of the wavefront, W(r) = A*r 2 Here, A is a function.

[0114] The wavefront curvature, or curvature-based power, Pc, is a function of the second derivative of the wavefront. The wavefront slope, or slope-based power, Ps, is a function of the first derivative of the wavefront and varies with the slope of the wavefront.

[0115] For a simple spherical lens, the curvature-based refractive power Pc is defined as follows: JPEG0007649846000001.jpg942 The slope-based refractive power Ps is defined as follows: JPEG0007649846000002.jpg936In other words, in the case of a simple lens assumed to be paraxial, Pc = Ps.

[0116] For lenses according to embodiments of the present disclosure, Pc is a function of the second derivative of the wavefront, so the curvature-based power profile gives the power of the annular and central regions of the lens, independent of the relative orientation of the regions. However, in the lens, the annular regions are "tilted" radially outward or radially inward with respect to the central region. Thus, while their slopes S are changed from their "untilted" values, their curvatures are not changed, and therefore the slope-based lens power Ps does not give the same value as the power Pc.

[0117] 11A and 11B show a lens 301 according to one embodiment of the present disclosure. The lens 301 is similar to the lens shown in Figs. 5A to 7C, but has an additional concentric annular region 303' acting as a second additional power zone. The power profile of the lens 301 varies in an oscillatory manner as a function of radial distance for different θ values. The additional power of the second annular region 303' varies in a similar manner to the first annular region 303 (including maximum and minimum values ​​at the same θ values, i.e., meridian). Fig. 12 shows the optical power as a function of radius for line AA (θ=0°), which is the line of maximum additional power, with 0 on the x-axis corresponding to the center of the central region 305.

[0118] In FIG. 12, a solid line graph (curve, transition line) 331 indicates the slope-based refractive power Ps, and a dashed line graph (curve, transition line) 333 indicates the curvature-based refractive power Pc.

[0119] The lens of Figures 11A and 11B has a nominal base power of -0.75 diopters (D). As shown in Figure 12, the slope-based power Ps and the curvature-based power Pc are approximately constant (and equal) throughout the central region of the lens 305. For the lens of Figures 11A and 11B, as with the lens shown in Figure 4D, the center of the circle defining the radius of curvature of the anterior surface of the annular region 303a is shifted with respect to the center of the circle defining the radius of curvature of the anterior surface of the central region 305. Since Ps is a function of the slope of the lens surface, the combination of the slope and curvature of the annular region 303a relative to the central region 305 results in a sagittal power Ps that slopes along a gradient that starts more negative than the distance power ("negative add" power) at the inner edge of the annular region 303a and increases with increasing radius to a less negative power than the distance power (add) at the outer edge of the annular region 303a. The slope of the annular region 303a is selected to ensure that the sagittal power Ps of the lens 301 at the radial midpoint of the annular region 303a matches the power of the central region 305 (specifically, the power that the central region would have if it were extended to that midpoint, as indicated by arrow 306 in FIG. 12 and dashed line 306' in FIG. 11A). Therefore, the inclination of the annular region 303a is selected so that the average add power is (at least approximately) 0D according to the sagittal method of calculating refractive power.

[0120] The distance region 308 between the first annular region 303a and the second annular region 303a' nominally has the same refractive power as the central region 305, but depending on the asphericity choice and general lens design practices, it may have the same negative refractive power relative to the central zone, or it may have somewhat more or less negative refractive power.

[0121] As mentioned above, the true optical power Pc is a function of the lens curvature, i.e., the second derivative of the wavefront, and is not affected by the tilt of the annular regions 303a / 303a'. As can be seen in Fig. 12, the curvature-based optical power of the annular regions 303a / 303a' is positive, i.e., the regions provide additional optical power across their width, which in this example increases with increasing radial distance from the lens center.

[0122] FIG. 13 shows a further lens 401 according to an embodiment of the present disclosure, with a single annular region 403 of nominal power -0.75D. FIG. 14 shows the variation of the sagittal power of the lens 401 along different θ values. The variation of the sagittal power has a shape similar to that shown in FIG. 12. The sagittal power becomes less negative with increasing radius, and the slope of the sloping path across the annular region 403 is different at different θ values. The dashed graph (curve, progression line) 431 shows the sagittal power along the line AA (θ=0°), which intersects with the maximum addition power annular region 403a. The increase of the sagittal power with increasing radius is relatively steep. The dotted graph (curve, progression line) 433 and the solid graph (curve, progression line) 435 show the sagittal power along the lines CC and DD, respectively. Line CC intersects with the intermediate power region 403c, where the sagittal power has a shallower slope between the central region 405 and the annular region 403c. Line DD intersects with the low power region 403d, where the sagittal power has an even shallower slope between the central region 405 and the annular region 403d. Along line BB (θ=90°), the power of the annular region 403b is zero, and the power profile is a smooth extension of the power of the central region 405. The average sagittal power at the midpoint of the annulus 403 is the same for all θ values. It is equal to the power the central region would have if it were extended to that point. That is, the average sagittal power is 0D. However, it will be appreciated from the above discussion that the actual power, the curvature-based power, of the central region does provide additional power. The additional refractive power is greatest along line AA, less along line CC, even less along line DD, and 0D along line BB.

[0123] 15 is a two-dimensional plot showing the variation of Ps for a lens 901 according to one embodiment of the present disclosure. The annular region 903 has a maximum addition power meridian 903a at the apex of the lens (θ=0°). An intermediate addition power meridian 903b with minimum addition power is at the base of the lens (θ=180°).

[0124] FIG. 16 shows Ps as a function of radial distance from the center of the lens for the lens 901 of FIG. 15 (radius 0 corresponds to the center of the lens 901). The solid graph (curve, progression line) 933 shows Ps averaged along the circumference of the lens. Ps shows little change over the central region 905. As in FIGS. 12 and 14, over the annular region 903, the variation of Ps follows a sloping path starting from negative addition power at the inner edge of the annular region 903 and increasing with increasing radius on both sides to the center of the lens to positive addition power at the outer edge of the annular region 903. The average Ps graph (solid graph (curve, progression line) 933) is symmetrical about the center of the lens (radius value 0). The dashed graph (curve, progression line) 931 shows Ps along the vertical line VV (shown in FIG. 15). This line intersects the maximum addition power meridian 903a at θ=0° and passes through the intermediate addition power meridian 903b at θ=180°. Since these meridians have different addition powers, the dashed curve 931 is asymmetrical about the center of the lens, showing a greater slope along the maximum addition power meridian 903a at θ=0° and a shallower slope at θ=180°. The plot along the horizontal line (HH) shown in Figure 15 is not visible in Figure 16 because it coincides with the average Ps plot.

[0125] Fig. 17 shows a lens 501 according to one embodiment of the present disclosure. The lens 501 has a central region 505 and two annular regions 503, 503' separated by a further region 505' having a base power, and has a nominal power of -7D. Fig. 18 shows Pc of this lens 501 for two different values ​​of θ. θ 1 For θ = 0°, dashed graph 531, and line AA, which corresponds to the maximum add power region 503a / 503a', the curvature-based power is significantly less negative in the annular regions 503a and 503a', which indicates the add power effect of the annular regions 503a / 503a' compared to the central region 505. 2= 45°, which corresponds to the solid graph 533 and the intermediate add power region 503c / 503c'. The difference in curvature-based power between the central region 505 and the annular regions 503c, 503c' is less than along line AA, and therefore the add power is less. Line BB corresponds to θ 3 = 90°, which corresponds to dashed (light shaded) graph 535 and to the minimum add power region 503b / 503b' of the annular region. For this lens, the minimum add power is non-zero.

[0126] 5B, 5C, 6A, 6C, 7A-7C, 10 and 11B show flat focal planes, but as previously mentioned, in reality, as a result of the lens 601 working with the crystalline lens 659 of the eye 661, these image planes are curved image "shells", as shown in FIG. 19. The distal focal plane 617 is a curved surface that substantially coincides with the retina 657. FIG. 19 shows rays intersecting the lens 601 along line CC, which is a line along θ=45° and corresponds to the intermediate addition power region 603c of the lens 601. At the intermediate addition power focal plane 630c, rays from an infinitely distant point source that intersect the lens along line CC and pass through the central region 605 are not in focus. On the other hand, rays from a distant point source that intersect the lens along line CC and pass through the annular region 603c are in focus. However, light that intersects the lens along other meridians and passes through the annular region 603c is unfocused, so that no single image is formed at the intermediate add power focal plane 630c. As a result of the varying add power of the annular region 603a of the lens 601, different regions of the retina 657 are exposed to different levels of defocus. With respect to Figures 19 and 20A-C, references to lines AA, BB and CC refer to the corresponding lines shown in the preceding figures (see Figures 13 and 17).

[0127] In the embodiments of the present disclosure shown in the drawings, the lenses all have at least one maximum addition power meridian, at least one base power meridian, and at least one intermediate addition power meridian between the maximum addition power meridian and the base power meridian. In other embodiments, the lenses may not have a base power meridian.

[0128] In some embodiments of the present disclosure described above, the region of maximum add power coincides with a line along θ=0° and the region of zero add power coincides with a line along θ=90°. The add power varies in a continuous sinusoidal manner, as shown in Figure 20B, and thus has intermediate values ​​between lines AA and BB. In other embodiments, the add power may vary with θ in a stepped manner, as shown in Figure 20A, or as a sawtooth function, as shown in Figure 20B.

[0129] The period of change of the add power may also vary. For example, the maximum value of the add power may occur every 45°, every 30°, or every 20°, corresponding to different integer values ​​of n in Figs. 20A-20C. Figs. 21A-21D show the blur patterns produced at the distal focal plane by rays from a distant point source intersecting the lens and passing through the annular region for lenses according to embodiments of the present disclosure. Fig. 21A shows the blur pattern of a lens with a maximum add power every 180°. Fig. 21B shows the blur pattern of a lens with a maximum add power every 60°. Fig. 21C shows the blur pattern of a lens with a maximum add power meridian spanning 180°. The remainder of the annular region has the base power, and a narrow intermediate add power meridian smooths the boundary between the maximum add power meridian and the base power region. FIG. 21D shows the blur pattern for a lens with maximum addition power meridians every 90°.

[0130] In some embodiments of the present disclosure above, if multiple maximum addition power meridians are present, they occur at regular intervals along the circumference of the annular region. In other embodiments, the maximum addition power meridians may be irregularly spaced along the circumference of the lens. Each of the multiple maximum addition power meridians may have a different power, as shown in Figure 22A. As shown in Figure 22B, the maximum addition power meridians may have an asymmetric power profile.

[0131]

[0013] Embodiments of the present disclosure also provide a contact lens for use in preventing or slowing the onset or progression of myopia. The lens comprises an optical zone including a central region having a first optical axis and a base power that focuses light to a focal point on the first optical axis. The lens also includes an annular region surrounding the central region and including at least one maximum add power meridian that provides a maximum add power and focuses light to a plurality of focal points at a first distance from the first optical axis. The lens also includes at least one intermediate add power meridian that provides an intermediate add power between the zero diopter add power and the maximum add power and focuses light to a plurality of focal points at a distance different from the first optical axis than the first distance.

[0132] In the foregoing description, reference is made to integers or elements having known obvious or foreseeable equivalents, and such equivalents are incorporated herein as if set forth individually herein. Reference should be made to the claims to determine the true scope of the present disclosure. The claims should be construed to encompass all such equivalents. The reader will also understand that integers or features of the present disclosure described as advantageous, convenient, or the like are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that such optional integers or features may be beneficial in some embodiments of the present disclosure, but may be undesirable in other embodiments, and therefore may not be present in other embodiments.

Claims

1. 1. A contact lens for use in preventing or slowing the onset or progression of myopia, comprising: A central region; an annular region; an optical zone comprising the central region has a first optical axis and a curvature centered on the first optical axis, the curvature providing a base power; the annular region surrounds the central region; at least one maximum add power meridian providing maximum add power and having a curvature centered about a center of curvature at a first distance from the first optical axis; at least one intermediate add power meridian providing an intermediate add power between zero diopter add power and the maximum add power and having a curvature centered at a distance from the first optical axis different from the first distance; having the power of the annular region varies continuously between the at least one maximum power meridian and the at least one intermediate power meridian; A contact lens characterized by:

2. The annular region provides the base power and further includes at least one base power meridian having the curvature about the center of curvature of the central region.

2. The contact lens of claim 1.

3. The plurality of curvatures providing the base power, the maximum add power, and the intermediate add power are curvatures of the front surface of the lens.

3. The contact lens according to claim 1 or 2.

4. The lens has a sagittal power profile resulting from a profile of the annular region, the sagittal power profile having a midpoint sagittal power at a midpoint of the at least one maximum add power meridian, the midpoint sagittal power matching the power that the central region would have if it were extended to the midpoint.

4. The contact lens according to claim 1, wherein the contact lens is a reflective layer.

5. The annular region includes a periodic arrangement of a plurality of maximum addition power meridians separated by a plurality of intermediate addition power meridians.

5. The contact lens according to claim 1.

6. The optical power of the annular region varies sinusoidally, stepwise, triangularly, or sawtooth-like around the circumference of the annular region.

6. The contact lens of claim 5.

7. The central region is circular in shape and has a diameter between 2 mm and 7 mm.

7. The contact lens according to claim 1.

8. The annular region extends radially outwardly from the periphery of the central region between 0.5 mm and 1.5 mm.

8. The contact lens according to claim 1, wherein the contact lens is a crystalline lens.

9. The base power is between 0.5 and -15.0 diopters.

9. The contact lens according to claim 1.

10. The maximum addition power meridian of the annular region is between +0.5 and +15.0 diopters of addition power.

10. The contact lens according to claim 1.

11. At least two concentric annular regions Equipped with Each of the annular regions comprises: at least one maximum add power meridian providing maximum add power and having a curvature centered about a center of curvature at a first distance from the first optical axis; at least one intermediate add power meridian providing an intermediate add power between zero diopter add power and the maximum add power and having a curvature centered at a distance from the first optical axis different from the first distance; have 11. The contact lens according to claim 1.

12. The lens comprises an elastomeric material, a silicone elastomeric material, a hydrogel material, or a silicone hydrogel material, or a mixture thereof.

12. A contact lens according to any one of claims 1 to 11.

13. The lens is a molding contact lens.

13. A contact lens according to any one of claims 1 to 12.

14. A method for producing a contact lens according to any one of claims 1 to 13, comprising the steps of: Forming a contact lens having a central region and an annular region. Equipped with the central region having a base power; the annular region surrounds the central region; at least one maximum add power meridian providing maximum add power and having a curvature centered about a center of curvature at a first distance from the first optical axis; at least one intermediate add power meridian providing an intermediate add power between zero diopter add power and the maximum add power and having a curvature centered at a distance from the first optical axis different from the first distance; having the power of the annular region varies continuously between the at least one maximum power meridian and the at least one intermediate power meridian; A method comprising:

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