Contact lens and related methods

Abstract

The invention discloses a contact lens (101). The lens (101) comprises an optical zone (102). The optical region (102) comprises a central region (105) having a center of curvature on an optical axis (119). The optical zone (102) comprises a first annular region (103). The first annular region (103) has an off-axis center of curvature at a first distance from the optical axis (119). The first annular region (103) has a sagittal diopter measure curve that increases with an increasing radial distance from the optical axis (119) with a gradient between 1.0 D / mm and 20.0 D / mm. The sagittal diopter matches an average radial sagittal diopter of the central region (105) at a point midway across the width of the first annular region (103).

Description

Technical Field

[0001] This application claims the rights under 35 U.S.C. §119(e) to prior U.S. Provisional Patent Application No. 63 / 354,120, filed on June 21, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to contact lenses. The present invention particularly, but not exclusively, relates to contact lenses for slowing the progression of myopia. The present invention also particularly, but not exclusively, relates to contact lenses for use by presbyopes. The present invention also relates to methods of making such lenses. Background Art

[0003] Many people (including children and adults) need contact lenses to correct myopia (nearsightedness) and many adults may need lenses to correct presbyopia (age-related inability to accommodate and therefore focus on nearby objects).

[0004] Myopic eyes focus incoming light from distant objects at a location in front of the retina. Therefore, the light converges toward a plane in front of the retina and diverges toward the retina and is out of focus when it reaches the retina. Conventional lenses (such as spectacle lenses and contact lenses) used to correct myopia reduce the convergence of incoming light from distant objects (for contact lenses) or cause divergence of incoming light (for spectacle lenses) before it reaches the eye, so that the location of the focus is displaced on the retina.

[0005] Presbyopia is the inability of a person with presbyopia to focus on nearby objects because the shape of the eye does not change effectively to accommodate nearby objects. Conventional lenses (e.g., spectacle lenses and contact lenses) used to correct presbyopia include bifocals or progressive lenses that include an area optimized for near vision and an area optimized for far vision. Presbyopia can also be treated using bifocals or multifocals lenses or single-focal lenses (where different prescriptions are provided for each eye, with one eye providing a farsighted lens and one eye providing a nearsighted lens).

[0006] Decades ago it was suggested that myopia progression in children or young adults could be slowed or prevented by undercorrection (i.e., moving the focus toward, but not completely onto, the retina). However, this approach necessarily results in degraded distance vision compared to the visual acuity obtained using a lens that fully corrects myopia. Furthermore, it is now questionable whether undercorrection is effective in controlling developing myopia. The most recent approach to correcting myopia is to provide lenses with both one or more areas that provide full correction for hyperopia and one or more areas that undercorrect or intentionally induce myopic loss of focus. It is suggested that this approach can prevent or slow myopia development or progression in children or young adults while providing good hyperopia.

[0007] Where a lens has zones that provide defocus, the zone that provides full correction for farsightedness is often referred to as a base power zone and the zone that provides undercorrection or intentionally induced myopic defocus is often referred to as a myopic defocus zone or an added power zone (because the power is more positive or less negative than the power of the distance zone). The surface (usually the front surface) of the added power zone has a radius of curvature that is smaller than the radius of curvature of the distance power zone and therefore provides a more positive or less negative power to the eye. The added power zone is designed to focus incoming parallel light (i.e., light coming from a distance) into the eye in front of the retina (i.e., closer to the lens), while the distance power zone is designed to focus light and form an image at the retina (i.e., farther away from the lens).

[0008] One known type of contact lens that reduces myopia progression is a bifocal contact lens available under the name MISIGHT (CooperVision, Inc.). This bifocal lens is different from bifocal or multifocal contact lenses configured to improve vision in the elderly because the bifocal lens is configured with specific optical dimensions to accommodate a person using distance correction (i.e., base power) to view both distant objects and accessory objects. The treatment area of ​​the bifocal lens with added power also provides a near-vision out-of-focus image at both the distance and near vision distances.

[0009] Although these lenses have been found to be beneficial in preventing or slowing the development or progression of myopia, the annular add-power zone can produce unwanted visual side effects. Light focused by the annular add-power zone in front of the retina diverges from the focal point to form an out-of-focus ring at the retina. As a result, 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 and car headlights. Furthermore, in theory, the wearer may utilize the additional focal point in front of the retina created by the annular add-power zone to focus on nearby objects, rather than using the eye's natural accommodation (i.e., the eye's natural ability to change focus) to focus on nearby objects; in other words, the wearer may inadvertently use the lens in the same manner as a presbyopia correction lens, which is undesirable for young subjects.

[0010] For treating myopia, we recognise that it may be beneficial to provide a lens that introduces additional myopic defocus. For treating presbyopia, it may be beneficial to provide a lens that produces an extended depth of focus.

[0011] The present disclosure provides improved lenses for young subjects that prevent or slow the progression of myopia. Summary of the invention

[0012] According to a first aspect, the present disclosure provides a contact lens. The lens includes an optical zone. The optical zone includes a central region having a center of curvature on a first optical axis. The optical zone includes a first annular region having an off-axis center of curvature at a first distance from the optical axis. The first annular region has a sagittal diopter variation curve that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 diopters (D) / mm and about 20.0 D / mm. At a point midway across the radial width of the first annular region, the radial sagittal diopter is equal to the average radial sagittal diopter of the central zone.

[0013] According to a second aspect, the present disclosure provides a method of manufacturing a contact lens according to the first aspect. The method includes forming a contact lens, wherein the lens includes: a central region, the central region having a base refractive power; and a first annular region, wherein the first annular region has an off-axis center of curvature at a first distance from the optical axis. The first annular region has a sagittal diopter variation curve that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0D / mm and about 20.0D / mm. At a point midway across the radial width of the first annular region, the sagittal refractive power is equal to the average sagittal refractive power of the central region.

[0014] According to a third aspect, the present disclosure provides a method of reducing myopia progression. The method comprises providing a contact lens according to the first aspect to a myopic person who is capable of adapting to different near distances.

[0015] It will of course be appreciated that features described with respect to one aspect of the present disclosure may be incorporated into other aspects of the present disclosure. For example, the method of the present disclosure may incorporate features described with reference to the apparatus of the present disclosure and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Example embodiments will now be described, by way of example only, with reference to the accompanying drawings.

[0017] FIG. 1A is a top view of a prior art contact lens for preventing myopia;

[0018] 1B is a side view of the contact lens of FIG. 1A .

[0019] Figure 2A is a schematic ray diagram of the lens of Figures 1A to 1B when the lens is positioned on the eye;

[0020] Figure 2B shows the light pattern at the near focus curve of the lens of FIG. 1A formed by a far point source when the lens is positioned on the eye;

[0021] Figure 2Cshows the light pattern at the far focus curved surface of the lens of FIG. 1A formed by a far point source when the lens is positioned on the eye;

[0022] Figure 3A is a top view of a lens according to an embodiment of the present disclosure;

[0023] Figure 3B yes Figure 3A A side view of a contact lens;

[0024] Figure 4A When the lens is positioned on the eye, Figure 3A Schematic ray diagram of the lens to B;

[0025] Figure 4B Shows the image formed by a distant source when the lens is positioned on the eye. Figure 3A The light pattern at the near-focus surface of the lens to B;

[0026] Figure 4C Shows the image formed by a distant source when the lens is positioned on the eye. Figure 3A The light pattern at the far-focus surface of the lens to B;

[0027] Figure 4D When the lens is positioned on the eye, Figure 3A A partial ray diagram of the lens to B together with circles indicating the radius of curvature of the center distance area (solid circle) and the annular added area (dashed circle) of the contact lens;

[0028] Figure 5 It varies according to the radial distance from the optical axis of the lens Figure 3A to the curvature power chart of the lens from B;

[0029] Figure 6 It varies according to the radial distance from the optical axis of the lens Figure 3A sagittal power chart of lenses to B;

[0030] Figure 7 is a top view of another lens having two concentric annular zones, each annular zone having a +4.0D curvature added power according to an embodiment of the present disclosure;

[0031] Figure 8 It varies according to the radial distance from the optical axis of the lens Figure 7 The curvature power chart of the lens;

[0032] Fig. 9 It varies according to the radial distance from the optical axis of the lens Figure 7 sagittal diopter chart of lenses;

[0033] Fig.10is a top view of another lens having two concentric annular zones, each annular zone having a +8.0D curvature added power according to an embodiment of the present disclosure;

[0034] Fig.11 It varies according to the radial distance from the optical axis of the lens Fig.10 The curvature power chart of the lens;

[0035] Fig.12 It varies according to the radial distance from the optical axis of the lens Fig.10 sagittal diopter chart of lenses;

[0036] Fig.13A is a graph showing the sagittal power variation as a function of radial distance for lenses having various curvature added powers;

[0037] Fig. 13B is a graph showing the variation of the sagittal power gradient for annular zones having different curvature added powers and positioned at different radial distances from the center of the lens. DETAILED DESCRIPTION

[0038] According to a first aspect, the present disclosure provides a contact lens. The contact lens comprises an optical zone. The optical zone comprises a central region having a center of curvature on the optical axis. The optical zone comprises a first annular region having an off-axis center of curvature at a first distance from the optical axis. The first annular region has a sagittal diopter profile that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 D / mm and about 20.0 D / mm, and at a point midway across the radial width of the first annular region, the radial sagittal power is equal to the average radial sagittal power of the central region.

[0039] As used herein, the term contact lens refers to an ophthalmic lens that can be placed on the front surface of the eye. It should be understood that such a contact lens will provide clinically acceptable on-eye movement and will not bind to a person's eye or eyes. The contact lens can be in the form of a corneal lens (e.g., a lens placed 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.

[0040] A contact lens according to the present disclosure includes an optical zone. The optical zone encompasses a portion of the lens that is optically functional. The optical zone is configured to be positioned above the pupil of an eye when in use. For a contact lens according to the present disclosure, the optical zone includes the central area and the first annular area surrounding the central area. 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 it provides a mechanical function, such as increasing the size of the lens, thereby making the lens easier to handle, providing a weight to prevent rotation of the lens and / or providing a shaping area that improves the comfort of the lens wearer. The peripheral zone may extend to the edge of the contact lens.

[0041] Contact lenses according to embodiments of the present disclosure may include a weight to orient the lens when the lens is positioned on the wearer's eye. When placed on the wearer's eye, embodiments of the present disclosure that incorporate a weight into the contact lens will rotate to a predetermined repose angle under the action of the wearer's eyelid; for example, the weight may be a wedge and the rotation may be caused by the action of the eyelid on the wedge. Weighting contact lenses to orient contact lenses is well known in the art; for example, weighting a double-curved contact lens to orient the lens so that the orthogonal cylindrical correction provided by the lens is properly aligned for the astigmatism of the wearer's eye.

[0042] The contact lens is generally circular in shape and has a diameter from about 4 mm to about 20 mm. The optical zone is generally circular in shape and may have a diameter from about 2 mm to about 10 mm. In some embodiments, the contact lens has a diameter from 13 mm to 15 mm and the optical zone has a diameter from 7 mm to 9 mm.

[0043] The optical axis may be located along the centerline of the lens. The central region may focus light from a distant object on the optical axis to a point on the optical axis at the afocal surface. The term surface as used herein does not refer to a physical surface, but rather to a surface that can be drawn through the points where light from distant objects will be focused. This surface is also referred to as an image plane (even though it may be a curved surface) or an image shell. The eye focuses light on the curved retina, and in a fully focused eye, the curvature of the image shell will match the curvature of the retina. Therefore, the eye does not focus light on a flat mathematical plane. However, in the art, the curved surface of the retina is often referred to as a plane.

[0044] The shape of the central region may be generally circular and may have a diameter between about 2 mm and about 9 mm, preferably between about 2.5 mm and about 4 mm. The shape of the central region may be generally elliptical. The first annular region may extend radially outward from the periphery of the central region by between about 0.1 mm and 4 mm, preferably between about 0.5 mm and 1.5 mm. Thus, the radial width of the first annular region may be between about 0.1 mm and about 4 mm, and preferably may be between about 0.5 mm and about 1.5 mm. The periphery of the central region may define a boundary between the central region and the first annular region, and thus, the first annular region may be adjacent to the central region.

[0045] The first annular region may be adjacent to the central region. A mixing region may be provided between the central region and the annular region. The mixing region should not substantially affect the optics provided by the central region and the annular region, and the mixing region may have a radial width of 0.05 mm or less, but in some embodiments it may also be as wide as 0.2 mm, or as wide as 0.5 mm.

[0046] Light rays from distant point sources passing through the first annular region may be focused away from the optical axis onto the add-diopter focal surface. Light rays passing through the central region will form an on-axis blur circle at the add-diopter focal surface. Light rays from distant point sources passing through the first annular region may be focused outside the blur circle.

[0047] The central region can focus light from a distant object to a point on the first optical axis at the afocal surface. The first annular region can limit the spread of off-axis light at the afocal surface, for example by acting as a beam stop, which can improve the optical contrast of an image produced by the lens.

[0048] In the context of the present disclosure, the power of the central and annular regions of a lens may be defined as the radial curvature power, the circumferential curvature power, the radial sagittal power, and the circumferential sagittal power.

[0049] The curvature and sagittal power are defined as follows:

[0050] For a wavefront W, at a point that is a radial distance r (the pupil radius) from a line perpendicular to the center of the wavefront, W(r) = A*r 2 , where A is a function.

[0051] Wavefront curvature or curvature diopter P c is a function of the second derivative of the wavefront. Wavefront slope (or based on the slope, or sagittal diopter P S ) is a function of the first derivative of the wavefront and varies with the slope of the wavefront.

[0052] Curvature diopter P c yes And for a simple spherical lens, Sagittal diopter P S yes and For a simple on-axis lens with a spherical wavefront, under the paraxial assumption, P C =P S .

[0053] The radial curvature power is the curvature power in a direction extending radially outward from the optical axis of the lens. The circumferential curvature power is the curvature power at a constant radial coordinate extending around the circumference of the lens.

[0054] The radial sagittal power is the sagittal power in a direction extending radially outward from the optical axis of the lens. The circumferential sagittal power is the sagittal power at a constant radial coordinate extending around the circumference of the lens.

[0055] The central zone may have a radial curvature diopter that is the same as the sagittal diopter and a circumferential curvature diopter that is the same as the sagittal diopter. The radial curvature diopter may be the same as the circumferential curvature diopter. The radial curvature diopter of the central zone may be referred to as the base curvature diopter or base diopter hereinafter. The radial sagittal diopter may be the same as the circumferential sagittal diopter. The radial sagittal diopter of the central zone may be referred to as the base sagittal diopter hereinafter. The base curvature diopter may be equal to the base sagittal diopter. The nominal diopter of the central zone will correspond to the marked refractive diopter of the contact lens as provided on the contact lens package (but in reality it may not have the same value). This will be the average sagittal or average curvature diopter taken across the central zone.

[0056] For a lens used to treat myopia, the base power will be negative or close to zero, and the central zone will correct for hyperopia. The base curvature power may be between 0.5 diopters (D) and -15.0 diopters. The base curvature power may be from -0.25 D to -15.0 D. The central zone of the lens may have a curvature that provides the base power.

[0057] The first annular region may have a curvature that provides a radial curvature with added power.

[0058] For lenses according to embodiments of the present disclosure, the first annular zone will have a radial curvature power that is greater than the radial curvature power of the central zone. Hereafter, the difference in the radial curvature power of the first annular zone and the central zone may be referred to as the radial curvature add-on power or the curvature add-on power. The circumferential curvature power of the first annular zone may be the same as the circumferential curvature power of the central zone. The net radial curvature power of the first annular zone will be the sum of the base radial curvature power and the radial curvature add-on power. For example, for a lens having a base radial curvature power of -3.0D and a first annular zone having a radial curvature add-on power of +4.0D, the net radial curvature power of the first annular zone will be +1.0D.

[0059] The base curvature power of the lens may be positive, and the first annular zone may have an added power of curvature that is more positive than the base curvature power. In this case, the added power focal surface will be closer to the lens than the far focal surface. An on-axis image will not be formed by light passing through the annular zone. Therefore, the wearer of the lens will need to use the natural accommodation of their eyes to focus on nearby objects. It is possible that the light rays focused by the annular zone will not intersect the optical axis of the contact lens at all, or will not intersect it until after it passes through the additional power focal surface.

[0060] The base curvature power of the lens may be negative, and the first annular zone may have a curvature add power that is not more negative than the power of the base zone, or the first annular zone may have a positive curvature power. Considering the lens positioned on the cornea, if the curvature add power of the first annular zone is not more negative than the base power, the add power focal surface will be further forward in the eye than the afocal surface. Considering the lens when not positioned on the cornea, if the curvature add power of the first annular zone is positive, the add power focal surface will be on the (image) side of the lens opposite to the afocal surface (which will be the virtual focal surface on the object side of the lens); if the curvature add power of the first annular zone is negative (but not more negative than the base curvature power), the virtual add power focal surface will be further from the lens than the virtual afocal surface.

[0061] The radial curvature added diopter of the first annular zone may be between +0.0 D and +20.0 D, preferably between +2.0 D and +10.0 D. The curvature added diopter of the first annular zone may have the same value, or the same diopter profile, along each meridian of the first annular zone (i.e., the radial curvature added diopter may be constant in the circumferential direction around the first annular zone).

[0062] In the context of the present disclosure, the first annular area is a generally annular area surrounding the optical zone. It may have a generally circular shape or a generally elliptical shape. It may completely surround the optical zone. It may partially surround the optical zone.

[0063] The first annular region of the lens will be tilted relative to the central region. As used herein, the tilt of the first annular region means radial tilt rather than lateral tilt. Thus, for example, in a radial cross-section of the lens, the outer end of the arc defining the front surface of the first annular region may be displaced above or below its position in the corresponding non-tilted annular region. Correspondingly, in three dimensions, the circumferential boundary of the first annular region (formed by the end of the radial arc) may be displaced above or below its position in the corresponding non-tilted annular region. In practice, the tilt may be embodied in the optical design of the front surface of the first annular region of the lens. Alternatively, the tilt may be embodied in the optical design of the rear surface of the first annular region of the lens or in the optical design of both the front and rear surfaces of the first annular region of the lens.

[0064] The tilting of the first annular zone relative to the central zone displaces the center of curvature of the first annular zone by a first distance from the optical axis. Tilting the first annular zone relative to the central zone changes the radial sagittal power of the first annular zone, since this is a function of the first derivative of the wavefront, but does not change the radial curvature power of the annular zone, which is a function of the second derivative of the wavefront. Due to the tilting, the radial sagittal power of the annular zone will vary across the width of the annular zone. Due to the tilting, the first annular zone has a radial sagittal diopter variation curve that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 D / mm and about 20.0 D / mm, and the degree of tilt is selected so that at a point midway across the radial width of the first annular zone, the radial sagittal power is equal to the average radial sagittal power of the central zone. The average radial sagittal power of the central zone can be determined by taking the average radial sagittal power value along the diameter of the central zone. Matching the average sagittal power of the central zone to the sagittal power at a point midway across the radial width of the first annular zone can provide improved control of spherical aberration. Spherical aberration can cause the average sagittal power across the first annular zone to vary with the nominal or labeled refractive power of the lens. This can result in poor visual quality for wearers of lenses with relatively high nominal powers. By matching the average sagittal power of the central zone to the sagittal power at a point midway across the radial width of the first annular zone, unintentional sagittal power variations caused by spherical aberration can be avoided.

[0065] The tilting of the first annular zone will produce a radial sagittal power as a ramp function that starts to be more negative than the radial sagittal power at the outer edge of the central zone and increases with increasing radial distance from the optical axis of the lens. The radial sagittal diopter variation curve across the first annular zone from the inner edge of the first annular zone (i.e., the edge closest to the optical axis of the lens) to the outer edge (i.e., the edge closest to the peripheral zone) can be defined by a curve or line with a positive gradient between about 1.0 D / mm and about 20.0 D / mm, preferably between about 1.0 D / mm and about 6.0 D / mm. The radial sagittal diopter variation curve across the first annular zone can be linear, or can be defined by a curve with an average gradient between about 1.0 D / mm and about 20.0 D / mm, preferably between about 1.0 D / mm and about 6.0 D / mm.

[0066] The first annular zone may have a radial sagittal diopter profile that increases with increasing radial distance from the optical axis, with a gradient between about 2.0 D / mm and about 20.0 D / mm, preferably between about 4.0 D / mm and about 12.0 D / mm. Alternatively, the first annular zone may have a radial sagittal diopter profile that increases with increasing radial distance from the optical axis, with a gradient between about 1.0 D / mm and about 6.0 D / mm. The gradient will depend in part on the radial curvature power of the first annular zone. For a given tilt of the first annular zone relative to the central zone, the greater the curvature added power of the first annular zone, the greater the gradient of sagittal diopter increase across the first annular zone will be.

[0067] At a point midway across the width of the annular zone, the circumferential sagittal power of the first annular zone may be the same as the circumferential sagittal power of the central zone. The average circumferential sagittal power of the annular zone may be the same as the circumferential sagittal power of the central zone.

[0068] The radial sagittal power across the central zone of the lens may be nearly constant. The radial curvature power across the central zone may be nearly constant. The radial curvature power across the first annular zone may be nearly constant and will be greater than the radial curvature power across the central zone.

[0069] The radial sagittal diopter at the inner edge of the first annular region (i.e., the edge closest to the central region) may be between 0.1D and 5.0D less than the radial sagittal diopter at the outer edge of the central region. The radial sagittal diopter at the inner edge of the first annular region (i.e., the edge closest to the central region) may preferably be between about 0.5D and 2.5D less than the radial sagittal diopter at the outer edge of the central region. The radial sagittal diopter at the outermost edge of the first annular region (i.e., the edge closest to the peripheral zone) may be between 0.1D and 5.0D greater than the radial sagittal diopter at the outer edge of the central region. The radial sagittal diopter at the outer edge of the first annular region (i.e., the edge closest to the peripheral zone) may preferably be between 0.5D and 2.0D greater than the radial sagittal diopter at the outer edge of the central region.

[0070] The lens may include at least one additional annular area concentric with the first annular area. Each additional annular area will be inclined relative to the central area, and thus each additional annular area will have an off-axis center of curvature at a second distance from the optical axis. Each additional annular area will have a sagittal diopter variation curve that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0D / mm and about 20.0D / mm. Each additional annular area may have a sagittal diopter variation curve that increases with increasing radial distance from the optical axis, wherein the gradient is between about 4.0D / mm and about 20.0D / mm. Alternatively, each additional annular area may have a sagittal diopter variation curve that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0D / mm and 3.5D / mm.

[0071] Each additional annular zone may have a radial curvature power greater than the radial curvature power of the central zone.Each additional annular zone may have the same radial curvature power as the first annular zone, or a different radial curvature power than the first annular zone.

[0072] At a point midway across the radial width of each additional annular zone, the sagittal power of that zone may be equal to the average sagittal power of the central zone, and this may provide improved control of spherical aberration.

[0073] In a manner similar to the first annular region, each additional annular region will be tilted relative to the central region. Each additional annular region may be tilted relative to the central region by the same amount as the first annular region, or by a different amount than the first annular region. Tilting each additional annular region relative to the central region displaces the center of curvature of the annular region from the optical axis. The center of curvature of each additional annular region may be displaced from the optical axis by the same distance as the center of curvature of the first annular region. Alternatively, the center of curvature of each additional annular region may be displaced from the optical axis by a different distance than the center of curvature of the first annular region.

[0074] Tilting each additional annular zone relative to the central zone will modify the sagittal-sagittal power of the annular zone, as this is a function of the first derivative of the wavefront. Tilting will not modify the radial curvature power of the annular zone, as this is a function of the second derivative of the wavefront. Due to the tilting, each additional annular zone may have the same variation in sagittal-sagittal power as the first annular zone, or a different variation in sagittal-sagittal power than the first annular zone. Each additional annular zone may have a different sagittal-sagittal power gradient than the first annular zone, either due to a different tilt of each annular zone relative to the central zone or due to having a different curvature added power compared to the first annular zone.

[0075] The radial sagittal refractive power variation curve of each additional annular zone may depend on the radial position of the additional annular zone. An annular zone at a greater radial distance from the optical axis may have a greater radial sagittal refractive power gradient or a smaller radial sagittal refractive power gradient than the first annular zone. An annular zone at a greater radial distance from the optical axis may have a smaller radial sagittal refractive power gradient than the first annular zone, because at a greater radial distance from the optical axis, a smaller radial sagittal refractive power gradient can be used to achieve a given radial curvature diopter. Between the first annular zone and each additional annular zone, the lens may have a radial curvature diopter that is less than the radial curvature diopter of the first annular zone. The area of ​​the lens between the concentric annular zones may be referred to as the distance diopter zone hereinafter. Between the concentric annular zones, the lens may have a basic radial curvature diopter. Between the concentric annular zones, the lens may have a curvature centered on the optical axis. The radial sagittal refractive power variation curve of the lens between the annular zones may be similar to the radial sagittal refractive power variation curve of the central zone. The lens may include multiple concentric additional annular zones. The additional annular regions may be separated by distance regions having a base curvature power.

[0076] At a point midway across the radial width of each additional annular zone, the radial-sagittal power of the annular zone may be matched to the average radial-sagittal power of the central zone.

[0077] The curvature added power of each additional annular zone may have the same value or the same diopter profile along each meridian of the annular zone (i.e., the radial curvature added power may be constant in the circumferential direction around the annular zone). The curvature providing the base curvature power and the curvature added power of the first annular zone and any additional annular zones may be the curvature of the front surface of the lens. The curvature providing the base curvature and the curvature added power of the first annular zone and any additional annular zones may be the curvature of the back surface of the lens. The curvature providing the base curvature power and the curvature added power of the first annular zone and any additional annular zones may be the curvature of the front and back surfaces of the lens providing the combined effect.

[0078] The contact lens can be a toric contact lens. For example, a toric contact lens can include an optical zone that is shaped to correct a person's astigmatism.

[0079] The contact lens may include an elastomeric material, a silicone elastomeric 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 maintains water in a state of equilibrium and does not contain silicone chemicals. A silicone hydrogel is a hydrogel containing silicone chemicals. As described in the context of the present disclosure, the hydrogel material and the silicone hydrogel material have an equilibrium water content (EWC) of at least 10% to about 90% (wt / wt). In some embodiments, the hydrogel material or the silicone hydrogel material has an EWC of from about 30% to about 70% (wt / wt). In contrast, as described in the context of the present disclosure, the silicone elastomeric material has a water content of from about 0% to less than 10% (wt / wt). Typically, the silicone elastomeric material used with the present method or device has a water content of from 0.1% to 3% (wt / wt). Examples of suitable lens formulations include those with the following United States Adopted 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 A, stenfilcon B, stenfil ... B, stenfilcon A, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon B, stenfilcon ilcon) A, sinofilcon B, sinofilcon 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.

[0080] By way of example, the lens may comprise a hydrogel or silicone hydrogel contact lens having a lens diameter between 13 mm and 15 mm.

[0081] According to a second aspect, the present disclosure provides a method of manufacturing a contact lens. The method may include forming a contact lens, wherein the lens includes a central region having a center of curvature on an optical axis. The lens includes a first annular region. The first annular region has an off-axis center of curvature at a first distance from the optical axis. The first annular region has a sagittal diopter variation curve that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 D / mm and about 20.0 D / mm. At a point midway across the radial width of the first annular region, the sagittal diopter is equal to the average sagittal diopter of the central region.

[0082] The lens may comprise any of the features set out in relation to the first aspect above.

[0083] The first annular zone of the lens is tilted relative to the central zone. The tilting of the first annular zone relative to the central zone displaces the center of curvature of the first annular zone by a first distance from the optical axis. As a result of the tilting, the first annular zone has a radial sagittal diopter profile that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 D / mm and about 20.0 D / mm, and at a point midway across the radial width of the first annular zone, the radial sagittal diopter is equal to the average radial sagittal diopter of the central zone.

[0084] A method of manufacturing a lens may include tilting a first annular region relative to a central region such that a center of curvature of the first annular region is a first distance from the optical axis, and such that the first annular region has a radial sagittal diopter profile that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 D / mm and about 20.0 D / mm, and at a point midway across the radial width of the first annular region, the radial sagittal diopter is equal to the average radial sagittal diopter of the central region. In practice, the tilt may include incorporating the tilt into the optical design of an anterior surface of the first annular region of the first annular region of the lens, or into a posterior surface of the first annular region of the lens, or into both the anterior and posterior surfaces of the first annular region of the lens. The manufacturing method may include forming a female mold component having a concave lens forming surface and a male mold component having a convex lens forming surface. The method may include filling a gap between the female mold component and the male mold component with a bulk lens material. The method may further include curing the bulk lens material to form the lens.

[0085] The method may include the step of casting the contact lens by polymerizing the contact lens formulation located between the female mold member and the male mold member of the contact lens mold assembly. Alternatively, the method may include the step of lathing the surface of the contact lens. For example, a lathe may be used to cut the front surface of the contact lens to provide the desired optical properties.

[0086] The contact lens may be a molded contact lens. The lens may be formed by a casting process, a spin casting process, or a turning process, or a combination thereof. As understood by those skilled in the art, casting refers to molding a lens by placing a lens forming material between a female mold part having a concave lens component forming surface and a male mold part having a convex lens component forming surface.

[0087] In a third aspect of the present disclosure, a method of using the contact lens described herein is also provided. The method can be effective in reducing the progression of refractive errors, such as reducing the progression of myopia. When the lens of the present disclosure is used to reduce the progression of myopia, the method includes the step of providing the contact lens to a person whose eyes can adapt to different near distances (e.g., in a range from about 15 cm to about 40 cm). Some embodiments of the method include the step of providing the ophthalmic lens to a person from about 5 years old to about 25 years old. The providing can be performed by an eye care practitioner (e.g., an optician or optometrist). Alternatively, the providing can be performed by a lens dealer arranged to deliver the ophthalmic lens to the lens wearer.

[0088] FIG. 1A shows a schematic top view of a prior art lens for slowing myopia progression (e.g., myopia control). The lens 1 includes an optical zone 2 that covers the pupil and a peripheral zone 4 that is located above the iris. The peripheral zone 4 provides mechanical functions, including increasing the size of the lens, thereby making the lens 1 easier to handle, providing a weight to prevent the lens 1 from rotating, and providing a shaping area that improves the comfort of the wearer of the lens 1. The optical zone 2 provides the optical functionality of the lens 1, and the optical zone includes an annular zone 3 and a central zone 5. For this lens 1, the annular zone 3 has a radial curvature power that is greater than the base curvature power of the central zone 5. Figure 2A 1A-1B is a schematic ray diagram showing how the lens 1 of FIGS. 1A-1B focuses light when the lens is positioned on the eye. The focus 11 of the annular region 3 is located on the near focus curved surface 13, while the focus 15 for the central region 5 is located on the far focus curved surface 17 which is farther from the back surface of the lens 1. The focus 11 of the annular region 3 and the focus 15 of the central region 5 share a common optical axis 19. Figure 2B and 2C , for a point source at infinity, the light rays focused by the central area 5 form a focused image 23 at the far focus surface 17. The light rays focused by the central area 5 also produce an unfocused blurred light spot 27 at the near focus surface 13. The light rays focused by the annular area 3 form a focused image 21 at the near focus surface 13. The light rays focused by the annular area 3 diverge after the near focus surface 13, and the divergent light rays produce an unfocused ring 25 at the far focus surface 17. As discussed above, the unfocused ring image 25 may cause the wearer of the lens 1 to see a 'halo' around the focused distance image.

[0089] Figure 3AA schematic diagram of a lens 101 according to an embodiment of the present disclosure is shown. Similar to the prior art lens 1 shown in FIGS. 1A and 1B , the lens 101 includes an optical zone 102 and a peripheral zone 104 surrounding the optical zone 102. The optical zone 102 includes a central area 105 and a first annular area 103 surrounding the central area 105. Figure 4A , the central region 105 has a center of curvature on the optical axis 119. The first annular region 103 is tilted relative to the central region 105, and the first annular region 103 has an off-axis center of curvature at a first distance from the optical axis 119. The front surface of the first annular region 103 has a greater curvature than the front surface of the central region 105, and thus provides a greater diopter of curvature than the base diopter of the central region 105. Figure 4D yes Figure 3A A partial ray diagram of lens 101 from A to B, together with circles indicating the radius of curvature of the center distance region (solid circle) and the annular added region (dashed circle) of lens 101 when lens 101 is positioned on the eye. Figure 4D , the front surface of the central region 105 defines a portion of the surface of a sphere of larger radius 109. The front surface of the annular region 103 defines a curved annular surface having a smaller radius 106.

[0090] Figure 4C When the lens 101 is positioned on the eye, Figure 3A The light pattern formed by a distant point source at the afocal surface of the lens of FIG. 117 is focused by the light passing through the central region 105. The annular region 103 acts as a beam stop, which results in a small spot size 133 ( Figure 4A ),like Figure 4C As shown in .

[0091] Figure 4B Shows when the lens is positioned on the eye. Figure 3A The light pattern formed by the distant point source at the near focus surface of the lens 101 to B. No single image is formed at the near focus surface 113. Figure 4B As shown in FIG. 1 , at the near focus surface 113, for a point source at infinity, light passing through the central region 105 produces a blur circle 128, just like the lenses of FIGS. 1A to B and 2A to B. However, light from a distant point source passing through the annular region 103 produces a focus ring 122, as shown in FIG. Figure 4B As shown in , it encloses a blur circle 128. Figure 4BThe light pattern produced for a distant point source is shown. In contrast to the prior art lens 1 of FIG. 1 , the lens 101 of FIGS. 3 and 4 does not produce a single image or an axial image at the near focus surface 113 that can be used to avoid the need for the eye to accommodate nearby objects. For distant extended objects, the focused image formed at the near focus surface 113 is the convolution of (i) a focused image of the extended object obtained with a conventional lens having the optical power of the annular region 103, and (ii) an optical transfer function representing the optical effect of the annular region 103.

[0092] Contrary to the prior art lens of FIGS. 1 and 2 , a ring or 'halo' effect does not appear at the afocal curved surface 117 .

[0093] Figure 5 exhibit Figures 3A to 3B . The radial curvature diopter variation curve of the lens 101 shown in . The radial curvature diopter in diopters (D) is plotted as a function of the radial distance from the optical axis 119 of the lens 101. The x-axis of the graph is labeled as radial position in mm (where 0.00 mm coincides with the optical axis 119 of the lens). Figures 3A to 3B The lens 101 of FIG. 1 has a base curvature power of -3.0D across a central zone that extends radially outward a distance of about 2.00 mm from the optical axis 119. The annular zone 103 has a curvature that provides a radial curvature add power of +4.0D. The radial curvature add power is approximately constant across the width of the first annular zone 103. As discussed above, the radial curvature power is a function of the curvature of the lens 101 (i.e., the second derivative of the wavefront) and is not affected by the tilt of the annular zone 103 relative to the central zone 105.

[0094] Figure 6 exhibit Figures 3A to 3B The radial sagittal diopter variation curve of the lens 101 shown in FIG. The radial sagittal diopter in diopters (D) is plotted as a function of the radial distance from the optical axis 119 of the lens 101.

[0095] like Figure 6, the radial sagittal power is nearly constant and has a value of -3.0D across the central zone 105 of the lens 101, which extends outwardly toward a radial distance of 2.00 mm. For the lenses shown in FIGS. 3 and 4 , the annular zone 103 is tilted such that the center of the circle defining the radius of curvature of the anterior surface of the annular zone 103 is displaced relative to the center of the circle defining the radius of curvature of the anterior surface of the central zone 105. Since the radial sagittal power is a function of the slope of the lens surface, the tilt of the annular zone 103 relative to the central zone 105 produces a radial sagittal power variation across the annular zone 103 that is a ramp function 131 that starts out more negative than the radial sagittal power of the central zone 105 and increases with increasing radius to a radial sagittal power that is more positive than the radial power of the central zone 105. The gradient of the sagittal-sagittal power ramp 131 across the first annular zone 103 depends on the tilt of the first annular zone 103 relative to the central zone 105, and the diopter is added depending on the curvature of the first annular zone 103. The ramp 131 is curved and has an average gradient approaching 1.5 D / mm. The tilt of the annular zone 103 is selected so that the sagittal-sagittal power of the lens 301 at the radial midpoint of the annular zone 103 (i.e., midway across the radial width of the annular zone) 103 is equal to the average sagittal-sagittal power of the central zone 105.

[0096] Figure 7 A schematic diagram of another lens 201 according to an embodiment of the present disclosure is shown. The lens 201 includes an optical zone 202 and a peripheral zone 204 surrounding the optical zone 202. The optical zone 202 includes a central area 205, a first annular area 203 surrounding the central area 205, and a second concentric annular area 207 located at a radial distance from the central area 205 greater than the first annular area. Figure 3A In the lens shown in , the central zone 205 has a center of curvature on the optical axis. The first annular zone 203 is tilted relative to the central zone 205, and the first annular zone 203 has an off-axis center of curvature at a first distance from the optical axis. The front surface of the first annular zone 203 has a curvature greater than the front surface of the central zone 205, and provides a radial curvature power greater than the base curvature of the central zone 205. The first annular zone 203 has a curvature that provides a radial curvature add power of +4.0D.

[0097] The second annular zone 207 is also tilted relative to the central zone 205, but is tilted by a different amount than the first annular zone 203. The second annular zone 207 has an off-axis center of curvature at a first distance from the optical axis. The anterior surface of the second annular zone 207 has a curvature greater than the anterior surface of the central zone 205, and thus provides a radial curvature power greater than the base radial curvature power of the central zone 205. The second annular zone 207 also has a curvature that provides an added diopter of radial curvature of +4.0D.

[0098] Figure 8 exhibit Figure 7 The radial curvature diopter variation curve of the lens 201 shown in FIG. The radial curvature diopter in diopters (D) is plotted as a function of the radial distance from the center of the lens 201, wherein the radial position of 0.00 mm coincides with the optical axis. Figure 7 The lens 201 has a base radial curvature power of -3.0D across the central zone. The first annular zone 203 has a curvature that provides a radial curvature add power of +4.0D. The radial curvature add power is approximately constant across the width of the first annular zone 203. The second annular zone 207 also has a curvature that provides a radial curvature add power of +4.0D. Between the first annular zone 203 and the second annular zone 207, there is a distance zone 208 of the lens 201 having a curvature that provides the base radial curvature power.

[0099] Fig. 9 exhibit Figure 7 The sagittal diopter variation curve of the lens 201 shown in FIG. The sagittal diopter in diopters (D) is plotted as a function of the radial distance from the optical axis, where the radial position of 0.00 mm coincides with the optical axis. Similar to Figure 6 , the variation in sagittal-sagittal power is nearly constant (and equal) across the central region 205 of the lens 201 .

[0100] The first annular zone 203 is tilted such that the center of the circle defining the radius of curvature of the anterior surface of the annular zone 203 is displaced relative to the center of the circle defining the radius of curvature of the anterior surface of the central zone 205. Because the sagittal power is a function of the slope of the lens surface, the tilt of the first annular zone 203 relative to the central zone 205 produces a sagittal power that is a ramp function 231 that starts out more negative than the sagittal power of the central zone 205 and increases with increasing radius to a sagittal power that is more positive than the sagittal power of the central zone 205. The gradient of the sagittal power across the first annular zone 203 depends on the tilt of the first annular zone 203 relative to the central zone 205, and the power is added depending on the radius curvature of the first annular zone 203. The ramp 231 is curved and has an average gradient approaching 2.9 D / mm. The inclination of the annular zone 203 is selected so that the sagittal power of the lens 201 at the radial midpoint of the first annular zone 203 is equal to the average sagittal power of the central zone 205 .

[0101] The second annular zone 207 is also tilted relative to the central zone 205 so that the center of the circle defining the radius of curvature of the front surface of the second annular zone 207 is displaced relative to the center of the circle defining the radius of curvature of the front surface of the central zone 205. The tilt of the second annular zone 207 relative to the central zone 205 produces a radial sagittal power profile that is a ramp function 233 that starts more negative than the radial sagittal power of the central zone 205 at the inner edge of the annular zone 203 and increases with increasing radius to a more positive radial sagittal power than the radial sagittal power across the central zone 205. The tilt of the second annular zone 207 relative to the central zone 205 is different from the tilt of the first annular zone 203. The sagittal power profile of the second annular zone 203 is curved and has an average gradient approaching 1.1 D / mm. The tilt of the annular zone 203 is selected to ensure that the sagittal power of the lens 201 at the radial midpoint of the first annular zone 203 is equal to the average radial sagittal power of the central zone 205.

[0102] There is a distance zone 208 of the lens 201 between the first annular zone 203 and the second annular zone 207. The distance zone 208 between the first annular zone 203 and the second annular zone 207 nominally has the same refractive power as the central zone 205, but may have the same, slightly larger, or slightly smaller negative refractive power than the central zone 205 depending on the choice of asphericity and common lens design practices.

[0103] Fig.10 A schematic diagram of another lens 301 according to an embodiment of the present disclosure is shown. Figure 7 , the lens 301 includes an optical zone 302 and a peripheral zone 304 surrounding the optical zone 302. The optical zone 302 includes a central area 305, a first annular area 303 surrounding the central area 305, and a second concentric annular area 307 located at a radial distance from the central area 305 greater than the first annular area. Figure 3A and Figure 7 , the central zone 305 has a center of curvature on the optical axis. The first annular zone 303 is tilted relative to the central zone 305, and the first annular zone 303 has an off-axis center of curvature at a first distance from the optical axis. The front surface of the first annular zone 303 has a curvature greater than the front surface of the central zone 305, and thus provides a radial curvature diopter greater than the base curvature diopter of the central zone 305. The front surface of the first annular zone 303 has a curvature greater than the front surface of the central zone 305, and thus provides a radial curvature diopter greater than the base radial curvature diopter of the central zone 305. The first annular zone 303 has a curvature that provides an added diopter of radial curvature of +8.0D (i.e., significantly greater than Figure 7 The radial curvature of the lens shown in Figure 1 adds diopters).

[0104] The second annular zone 307 is also tilted relative to the central zone 305, but the tilt amount is different from the first annular zone 303. The second annular zone 307 has an off-axis center of curvature at a first distance from the optical axis. The front surface of the second annular zone 307 has a curvature greater than the front surface of the central zone 305, and thus provides a radial curvature power greater than the base radial curvature power of the central zone 305. The second annular zone 303 also has a curvature that provides a radial add curvature power of +10.0D.

[0105] Fig.11 exhibit Fig.10 The radial curvature refractive index variation curve of the lens 301 shown in FIG. Figure 7 301 has a base radial curvature power of -3.0D across a central zone 305. Plot the radial curvature power in diopters (D) as a function of radial distance from the center of the lens 301, where a radial position of 0.0 mm corresponds to the optical axis. The first annular zone 303 has a curvature that provides a radial curvature add power of +8.0D. The radial curvature add power is approximately constant across the width of the first annular zone 303. The second annular zone 307 also has a curvature that provides a radial curvature add power of +8.0D. Between the first annular zone 303 and the second annular zone 307, there is a distance zone 308 of the lens 301 having a curvature that provides a base curvature power.

[0106] Fig.12 exhibit Fig.10 . The radial sagittal diopter variation curve of the lens 301 shown in FIG. Plot the radial sagittal diopter in diopters (D) as a function of the radial distance from the center of the lens 301, where the radial position of 0.00 mm corresponds to the optical axis. Similar to FIG. 3 and Figure 7 For the lens shown in , the variation in sagittal power is nearly constant across the central region 305 of the lens 301 .

[0107] The first annular zone 303 is tilted such that the center of the circle defining the radius of curvature of the anterior surface of the annular zone 303 is displaced relative to the center of the circle defining the radius of curvature of the anterior surface of the central zone 305. Because the sagittal power is a function of the slope of the lens surface, the tilt of the first annular zone 303 relative to the central zone 305 produces a sagittal power that is a ramp function 331 that starts out more negative than the sagittal power of the central zone at the inner edge of the annular zone 303 and increases with increasing radius to a sagittal power that is more positive than the sagittal power of the central zone 305 at the outer edge of the annular zone 303. The radial curvature of the first annular zone adds power 303 (e.g., Fig.11 is significantly greater than Figure 7The radial curvature of the first annular zone 303 of the lens 201 shown in FIG. 2 adds diopters. This results in a steeper gradient of the radial sagittal diopter curve across the first annular zone 303. The slope 331 is curved and the average gradient is close to 5.5D / mm. The inclination of the annular zone 303 has been selected to ensure that the radial sagittal diopter of the lens 301 at the radial midpoint of the first annular zone 303 is equal to the average radial diopter of the central zone 305.

[0108] The second annular zone 307 is also tilted such that the center of the circle defining the radius of curvature of the anterior surface of the second annular zone 307 is displaced relative to the center of the circle defining the radius of curvature of the anterior surface of the central zone 305. The tilt of the second annular zone 307 relative to the central zone 305 produces a sagittal diopter profile that is a ramp function 333 that starts more negative than the sagittal diopter of the central zone 305 at the inner edge of the annular zone 303 and increases with increasing radius to a sagittal diopter that is more positive than the sagittal diopter across the central zone 305. The tilt of the second annular zone 307 relative to the central zone 305 is different from the tilt of the first annular zone 303.

[0109] The slope 333 is curved with an average gradient approaching 2.2 D / mm. The inclination of the annular zone 303 has been selected to ensure that the sagittal power of the lens 301 at the radial midpoint of the first annular zone 303 is equal to the average sagittal power of the central zone 305 .

[0110] There is a distance zone 308 of the lens 301 between the first annular zone 303 and the second annular zone 305. The distance zone 308 between the first annular zone 303 and the second annular zone 307 nominally has the same power as the central zone 305, but may have the same, slightly more, or slightly less negative power than the central zone 305 depending on the choice of asphericity and common lens design practices.

[0111] As explained above, for lenses according to embodiments of the present disclosure, the gradient of the sagittal-sagittal diopter variation curve across the annular zone adds diopter depending on the radial curvature of the annular zone, and on the tilt of the annular zone relative to the central zone of the lens. Fig.13AThe radial sagittal power curves as a function of radial distance from the optical axis are shown for lenses with different radial curvature add-on powers ranging from +2.0D to +10.0D. Each lens has two concentric annular zones, with the first annular zone (indicated as zone 403) being closer to the central zone (indicated as zone 405) than the second annular zone (indicated as zone 407). For each lens, the radial sagittal power across the central zone 405 is approaching constant. For each lens, at the boundary between the central zone and the first annular zone, there is a drop in the radial sagittal power due to the tilt of the first annular zone 403 relative to the central zone. For each lens, the relative tilt of the first annular zone relative to the central zone is the same. For each lens, the sagittal power increases across the width of the first annular zone. Between the first and second annular zones, there is a zone of the lens that has the same distance as the power of the central zone (indicated as zone 408). For each lens, at the boundary between the distance zone and the second annular zone, the sagittal power decreases again due to the inclination of the second annular zone relative to the central zone and relative to the distance zone. For each lens, the sagittal power increases across the width of the second annular zone. The inclination of the second annular zone relative to the central zone is the same for each lens. As the radial curvature of the lens adds diopters, the gradient of the sagittal power slope across the first annular zone and across the second annular zone increases. For example, the gradient of the sagittal power slope for the +10.0D lens (indicated by curve 445) is greater than the gradient of the sagittal power slope for the +2.0D lens (indicated by curve 447). Fig. 13B 5 is a graph showing how the gradient of the sagittal-sagittal power slope varies with added diopters of radial curvature for a first annular zone (indicated by curve 549) and a second annular zone (indicated by curve 551). The gradient of the sagittal-sagittal power slope increases with increasing added diopters of radial curvature, and the sagittal-sagittal power gradient across the second annular zone is less than the sagittal-sagittal power gradient across the first annular zone.

[0112] Although wholes or elements of known obvious or foreseeable equivalents are mentioned in the foregoing description, such equivalents are incorporated herein as if individually set forth. Reference should be made to the claims to determine the true scope of the present disclosure, which should be interpreted as covering any such equivalents. The reader should also understand that wholes or features of the present disclosure described as advantageous, convenient, etc. are optional and do not limit the scope of the independent claims. In addition, it should be understood that although such optional wholes or features may be beneficial in some embodiments of the present disclosure, they may not be desired in other embodiments and therefore may not exist.

Claims

1. A contact lens, comprising an optical zone, wherein the optical zone comprises: a central region having a center of curvature on the optical axis; and a first annular region having an off-axis center of curvature at a first distance from the optical axis; wherein the first annular zone has a radial sagittal power profile that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 D / mm and about 20.0 D / mm, and wherein at a point midway across the radial width of the first annular zone, the radial sagittal power is equal to the average radial sagittal power of the central zone.

2. The contact lens of claim 1, wherein the sagittal-sagittal diopter variation curve across the first annular zone is linear.

3. The contact lens of claim 1 or claim 2, wherein the sagittal-sagittal diopter variation curve across the first annular region defines a curve having an average gradient between about 1.0 D / mm and about 20.0 D / mm.

4. The contact lens of any preceding claim, wherein the annular region has a sagittal-sagittal diopter profile that increases with increasing radial distance from the optical axis, with a gradient between about 4.0 D / mm and about 12.0 D / mm.

5. The contact lens of any one of claims 1 to 3, wherein the annular zone has a sagittal-sagittal diopter profile that increases with increasing radial distance from the optical axis, with a gradient between about 1.0 D / mm and about 6.0 D / mm.

6. A contact lens according to any preceding claim, wherein the sagittal-sagittal power at the inner edge of the first annular region is between 0.5D and 2.5D less than the sagittal-sagittal power at the outer edge of the central region.

7. A contact lens according to any preceding claim, wherein the sagittal-sagittal power at the outer edge of the first annular region is between 0.5D and 2.0D greater than the sagittal-sagittal power at the outer edge of the central region.

8. The contact lens of any preceding claim, wherein the first annular region has a curvature that provides a radial curvature add diopter, wherein the radial curvature add diopter is between +2.0D and +10.0D.

9. The contact lens of any preceding claim, wherein the central region has a curvature that provides a base radial curvature power, wherein the base radial curvature power is between 0.5D and -15.0D.

10. The contact lens of any preceding claim, wherein the first annular region extends radially outwardly from the periphery of the central region by between 0.5 mm and 1.5 mm.

11. A contact lens according to any preceding claim, comprising at least one additional annular region concentric with the first annular region, each additional annular region having an off-axis center of curvature at a first distance from the optical axis, wherein each annular region will have a sagittal diopter gradient curve that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 D / mm and about 20.0 D / mm.

12. The contact lens of claim 11, wherein each additional annular zone has a different sagittal-sagittal power gradient than the first annular zone.

13. The contact lens of claim 11 or claim 12, wherein the sagittal-sagittal power gradient of each additional annular zone is dependent on the radial position of the annular zone.

14. The contact lens of any one of claims 11 to 13, wherein at a point midway across the radial width of each additional annular zone, the sagittal power is equal to the mean sagittal power of the central zone.

15. The contact lens of any one of claims 11 to 14, comprising a plurality of concentric additional annular zones, wherein the additional annular zones are separated by distance zones having the substantial radial curvature power.

16. The contact lens of any one of claims 9 to 15, wherein the substantial radial curvature power of the central zone is caused by the curvature of the front and / or back surface of the lens.

17. The contact lens of any one of claims 8 to 16, wherein the radial curvature power of the first annular zone and any additional annular zones is caused by the curvature of the anterior and / or posterior surface of the lens.

18. A contact lens according to any preceding claim, wherein the lens comprises an elastomeric material, a silicone elastomeric material, a hydrogel material or a silicone hydrogel material or a mixture thereof.

19. The contact lens of any preceding claim, wherein the lens is a molded contact lens.

20. A method of manufacturing a contact lens according to any preceding claim, the method comprising: A contact lens is formed, wherein the lens comprises: a central region having a center of curvature on the optical axis; and A first annular region having an off-axis center of curvature at a first distance from the optical axis, wherein the first annular region has a radial sagittal power profile that increases with increasing radial distance from the optical axis, wherein the gradient is between about 1.0 D / mm and about 20.0 D / mm, and wherein at a point midway across the radial width of the first annular region, the radial sagittal power is equal to the average radial sagittal power of the central region.

21. A method of reducing myopia progression, comprising: A contact lens according to any one of claims 1 to 19 is provided to a myopic person capable of adapting to different near distances.

Images