Contact lenses and related procedures

Abstract

A contact lens (201) and a method for manufacturing a lens (201) are described. The lens (201) comprises an optical zone (202) which includes a central region (205). The central region (205) has a first optical axis (219) and a first radius of curvature. The optical zone includes an annular region (203). The annular region (203) is inclined relative to the central region and has a radial curvature refractive power that is greater than the base refractive power. Light rays passing through the central region (205) form a focused image at a distal focal surface (217), and light rays passing through the annular region (203) do not form a point of light at the distal focal surface (217). At the boundary between the central region (205) and the annular region (203), the radial-sagittal refractive power increases.The radial-sagittal refractive power increases with increasing radial distance to the outer edge of the annular region (203).

Description

Technical field The present invention relates to contact lenses. In particular, but not exclusively, the present invention relates to contact lenses for slowing the progression of myopia. The present invention also relates in particular, but not exclusively, to contact lenses for use by presbyopes. The present invention also relates to methods for manufacturing such lenses. background Many people, both children and adults, need contact lenses to correct myopia (nearsightedness), and many adults need lenses to correct presbyopia (age-related inability to accommodate and therefore inability to focus on near objects). Myopic eyes focus light from distant objects onto a point in front of the retina. Consequently, the light converges towards a plane in front of the retina and diverges towards the retina, where it becomes blurred upon arrival. Conventional lenses (e.g., spectacles and contact lenses) used to correct nearsightedness reduce the convergence (in the case of contact lenses) or cause divergence (in the case of spectacles) of light from distant objects before it reaches the eye, thus shifting the focal point onto the retina. Presbyopic eyes do not effectively change their shape to focus on near objects, and therefore people with presbyopia cannot focus on near objects. Conventional lenses (such as eyeglasses and contact lenses) for correcting presbyopia include bifocal or progressive lenses, which have areas optimized for near vision and areas optimized for distance vision. Presbyopia can also be treated with bifocal or multifocal lenses, or with monovision lenses (where each eye has a different prescription, with one eye receiving a lens for distance vision and the other a lens for near vision). Several decades ago, it was believed that the progression of myopia in children and adolescents could be slowed or prevented by undercorrection, that is, by shifting the focal point to the retina, but not entirely onto it. However, this approach inevitably leads to a deterioration of distance vision compared to a lens that fully corrects the myopia. Furthermore, it is now considered doubtful that undercorrection can effectively combat developing myopia. A more recent approach to correcting myopia involves using lenses that have one or more areas that provide full correction for distance vision, as well as one or more areas that provide undercorrection or intentionally induce myopic defocusing.It is believed that this approach can prevent or slow down the development or progression of myopia in children and adolescents while ensuring good distance vision. In lenses with defocusing areas, the areas that provide full correction for distance vision are usually called base refractive power areas, and the areas that provide undercorrection or intentionally induce myopic defocusing are usually called myopic defocusing areas or addition refractive power areas (because the dioptric power is more positive or less negative than the refractive power of the distance areas). One surface (usually the front surface) of the addition area(s) has a smaller radius of curvature than that of the distance area(s) and therefore delivers a more positive or less negative refractive power to the eye. The addition refractive power area(s) is / are designed to focus parallel incident light (i.e., distance light) in front of the retina (i.e.,closer to the lens) focuses (focus), while the far refractive power area(s) is (are) designed to focus (focus) the light and produce (produce) an image on the retina (i.e. farther from the lens). A well-known type of contact lens that slows the progression of myopia is a dual-focus contact lens, available under the name MISIGHT (CooperVision, Inc.). This dual-focus lens differs from bifocal or multifocal contact lenses configured to improve the vision of presbyopes in that it is configured with specific optical dimensions to allow a person capable of accommodation to use the distance correction (i.e., the base power) for viewing both distant and near objects. The treatment zones of the dual-focus lens, which provide the addition power, also deliver a myopically defocused image at both distance and near. While these lenses have proven beneficial in preventing or slowing the development or progression of myopia, ring-shaped addition refractive power areas can cause undesirable visual side effects. Light focused by these ring-shaped addition refractive power areas in front of the retina deviates from the focal point, forming a defocused ring in front of the retina. Wearers of these lenses may therefore see a ring or "halo" around the images that form on the retina, especially with small, bright objects such as streetlights and car headlights. Instead of the eye's natural accommodation (i.e., focusing), the lenses allow the eye to focus more evenly.By utilizing the eye's natural ability to change its focal length to focus on nearby objects, wearers can theoretically use the additional focus in front of the retina resulting from the ring-shaped area of ​​added refractive power to focus on nearby objects; in other words, wearers can unintentionally use the lenses in the same way as lenses for correcting presbyopia, which is undesirable for young people. Further lenses have been developed that can be used in the treatment of myopia and serve to eliminate the halo effect observed around focused distance images with the MISIGHT lenses (CooperVision, Inc.) described above and other similar lenses. In these lenses, the ring-shaped area is designed so that no single, on-axis image is formed in front of the retina, thus preventing the eye from using such an image to avoid focusing on near objects. Instead, distant point light sources are imaged by the ring-shaped area into a ring-shaped focal line at a nearby additive focal point, resulting in a small spot of light without a surrounding halo effect on the retina at a distant focal point. To treat myopia, it can be beneficial to use a lens that provides additional myopic defocusing. To treat presbyopia, it can be beneficial to use a lens that allows for greater depth of field. Further state of the art is shown in document US 2019 / 227342 A1. Summary According to a first aspect, the present disclosure provides a contact lens with an optical zone. The optical zone has a central region, the central region having a first optical axis, a base radial refractive power, and a base radial sagittal refractive power. The central region has a center of curvature lying on the first optical axis. The optical zone has an annular region, the annular region having a radial refractive power of X at a point in the center of the annular region, where X is greater than the base radial refractive power. The annular region has an off-axis center of curvature located a first distance from the optical axis. At a point in the middle of its width, the annular region has a radial sagittal refractive power of Y, where Y is greater than the base radial sagittal refractive power and where Y is less than X. According to a second aspect, the present disclosure provides a method for manufacturing a lens. The method includes the shaping of the contact lens of the first aspect of the invention. It goes without saying that features described in relation to one aspect of the present revelation can be integrated into other aspects of the present revelation. For example, the procedure of the revelation may contain features described with reference to the apparatus of the revelation, and vice versa. Description of the characters Embodiments of the present invention are now described by way of example only, with reference to the accompanying schematic drawings: Fig. 1A is a schematic top view of a contact lens that uses a treatment zone which provides a myopically defocused image to reduce the progression of myopia; Fig. 1B is a side view of the contact lens from Fig. 1A; Fig. 2A is a ray diagram for the lens of Fig. 1A; Fig. 2B shows a light pattern at a proximal focal surface of the lens of Fig. 1A, originating from a distant point source; Fig. 2C shows a light pattern at a distal focal surface of the lens of Fig. 1A, originating from a distant point source; Fig. 3 is a partial ray diagram for the lens from Fig. 1A and Fig. 4.Fig. 1B together with circles indicating the radii of curvature of the central distance region (dashed-dotted line) and the annular addition region (dashed line) of the contact lens. Fig. 4A is a diagram showing the variation of the radial-sagittal refractive power for the lens shown in Fig. 1A and Fig. 1B; Fig. 4B is a diagram showing the variation of the radial curvature refractive power for the lens shown in Fig. 1A and Fig. 1B; Fig. 5A is a top view of another contact lens with non-coaxial optics; Fig. 5B is a side view of the contact lens from Fig. 5A; Fig. 6A is a ray diagram for the lens of Fig. 5A and Fig. 5B; Fig. 6B shows a light pattern at a proximal focal surface of the lens from Fig. 5A and Fig. 5B, originating from a distant point source; Fig. 6C shows a light pattern at a distal focal surface of the lens from Fig. 5A and Fig. 5B, originating from a distant point source; Fig.Figure 6D is a partial beam diagram for the lens of Figures 5A and 5B, together with circles indicating the radii of curvature of the central distance region (dashed-dotted line) and the annular addition region (dashed line) of the contact lens; Figure 7A is a diagram showing the variation of the radial-sagittal refractive power for the lens shown in Figures 5A and 5B; Figure 7B is a diagram showing the variation of the radial curvature refractive power for the lens shown in Figures 5A and 5B; Figure 8A is a top view of a lens according to an embodiment of the present disclosure; Figure 8B is a side view of the contact lens from Figure 8A; Fig. 9 is a partial beam diagram for the lens of Fig. 8A and Fig. 8B together with circles indicating the radii of curvature of the central distance region (dashed-dotted line) and the annular addition region (dashed line) of the contact lens; Fig.Figure 10A is a diagram showing the variation of the radial curvature refractive power for the lens shown in Figures 8A and 8B; Figure 10B is a diagram showing the variation of the radial sagittal refractive power for the lens shown in Figures 8A and 8B; Figure 11A is a ray diagram for the lens of Figures 8A and 8B; Figure 11B shows a light pattern at a distal focal surface of the lens from Figures 8A and 8B, originating from a distant point source; Figure 11C shows a light pattern in a first proximal focal plane of the lens of Figures 8A and 8B, originating from a distant point source; Figure 11D shows a light pattern in a second proximal focal plane of the lens of Figures 8A and 8B, originating from a distant point source; Fig. 12A is a top view of a lens according to an embodiment of the present disclosure, which has a variation in the radial curvature refractive power; Fig. 12B is a side view of the contact lens from Fig.12A; Fig. 13A is a schematic representation of the lens from Fig. 12A and Fig. 12B along line EE, together with circles indicating the radii of curvature of the central distance region (dashed-dotted line) and the annular addition region (dashed line) of the contact lens; Fig. 13B is a schematic representation of the lens from Fig. 12A and Fig. 12B along line FF, together with circles indicating the radii of curvature of the central distance region (dashed-dotted line) and the annular addition region (dashed line) of the contact lens; Fig. 14 is a schematic diagram showing the sinusoidal variation of the radial curvature refractive power with the angle θ around the annular region for the lens shown in Fig. 12A and Fig. 12B; Fig.Figure 15A is a schematic diagram showing a sinusoidal variation of the refractive power with angle θ around the annular region for a lens according to one embodiment of the present disclosure; Figure 15B is a schematic diagram showing a sawtooth variation of the refractive power with angle θ around the annular region for a lens according to one embodiment of the present disclosure; Figure 15C is a schematic diagram showing a rectangular variation of the refractive power with angle θ around the annular region for a lens according to one embodiment of the present disclosure; Figure 16 is a flowchart showing a method for designing a contact lens according to one embodiment of the present disclosure; and Figure 17 is a schematic representation of a radial cross-section through a portion of three modeled lenses that were modeled according to the method described in Figure 16. Detailed description According to a first aspect, the present disclosure provides a contact lens. The lens has an optical region comprising a central region, the central region having a first optical axis, a base radial refractive power, a base radial sagittal refractive power, and a center of curvature lying on the first optical axis. The central region has an annular region. The annular region has a radial refractive power of X at a point at mid-width of the annular region, X being greater than the base radial refractive power. The annular region has an off-axis center of curvature located at a first distance from the optical axis, such that the annular region has a radial sagittal refractive power of Y at a point at mid-width, Y being greater than the base radial sagittal refractive power and Y being less than X. The term "contact lens" as used here refers to an ophthalmic lens that can be placed on the front surface of the eye. It goes without saying that such a contact lens allows clinically acceptable movement on the eye and does not fuse with the eye or eyes. The contact lens may be corneal in shape (e.g., a lens that rests on the cornea of ​​the eye). The contact lens may be soft, such as a hydrogel or silicone hydrogel lens. The lens may be used to prevent or slow the development or progression of myopia. The lens may also be used to increase the depth of field in a nearsighted eye. A contact lens according to the present disclosure has an optical zone. The optical zone comprises the parts of the lens that have an optical function. The optical zone is configured to lie above the pupil of an eye when in use. In contact lenses according to the present disclosure, the optical zone has the central area and the annular area (or areas) 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 performs mechanical functions, such as magnifying the lens, thereby making the lens easier to handle, providing ballast to prevent rotation of the lens, and / or providing a shaped area that improves wearing comfort for the lens wearer.The peripheral zone can extend to the edge of the contact lens. A contact lens according to one embodiment of the disclosure may include a ballast to align the lens when it is placed on the wearer's eye. Embodiments of the disclosure that include a ballast in the contact lens, when placed on the wearer's eye, rotate into a predetermined resting angle under the action of the wearer's eyelid; for example, the ballast may be a wedge, and the rotation may result from the action of the eyelid on the wedge. It is generally known to provide a contact lens with a ballast to align it; for example, toric contact lenses are provided with a ballast to align the lens so that the orthogonal cylindrical corrections provided by the lens are correctly matched to the astigmatism of the wearer's eye.It is possible that the contact lens described in the present disclosure offers the wearer a particular benefit in a specific orientation. For example, the contact lens may be especially advantageous for the wearer if a meridian with maximum refractive power is located in a specific orientation. The contact lens can be essentially circular and have a diameter of approximately 4 mm to approximately 20 mm. The optical zone can also be essentially circular and have a diameter of approximately 2 mm to approximately 10 mm. In some embodiments, the contact lens has a diameter of 13 mm to 15 mm, and the optical zone has a diameter of 7 mm to 9 mm. The first optical axis can lie along the center line of the lens. The central area can focus light from a distant point object on the first optical axis onto a point on the first optical axis at a distal focal surface. The term "surface" used here does not refer to a physical surface, but to a surface that could be drawn by the points where the light from distant objects is focused. Such a surface is also called the image plane (even though it may be a curved surface) or image shell. The eye focuses the light onto the retina, which is curved, and in a perfectly focused eye, the curvature of the image shell would match the curvature of the retina; therefore, the eye does not focus the light onto a flat mathematical plane. However, in the scientific community, the curved surface of the retina is commonly referred to as a plane. The central region can be substantially circular and have a diameter between about 2 and 9 mm, preferably between 2 and 7 mm. The central region can be substantially elliptical. The annular region can extend radially outward from a circumference of the central region by about 0.1 to 4 mm, preferably between about 0.5 and 1.5 mm. For example, the radial width of the annular region can be about 0.1 mm to about 4 mm, and preferably about 0.5 mm to about 1.5 mm. The circumference of the central region can form a boundary between the central region and the annular region, and the annular region can therefore adjoin the central region. The annular area may adjoin the central area. A mixing area may be provided between the central area and the annular area. The mixing area should not significantly impair the optics of the central and annular areas, and the mixing area may have a radial width of 0.05 mm or less, although in some embodiments it may also be 0.2 mm or 0.5 mm wide. In the context of the present disclosure, the refractive power of the central and annular regions of the lens can be defined as radial curvature refractive power, circumferential curvature refractive power, mean curvature refractive power (which is the average of the radial and circumferential curvature refractive power), radial sagittal refractive power, circumferential sagittal refractive power and mean sagittal refractive power (which is the average of the radial and circumferential sagittal refractive power). The curvature and sagittal refractive power are defined as follows: For a wavefront W at a point at a radial distance r (pupil radius) from a line perpendicular to the center of the wavefront, W(r) = A*r2, where A is a function. The wavefront curvature, or curvature-based refractive power, Pc, is a function of the second derivative of the wavefront. The wavefront tilt, or tilt-based refractive power, PS, is a function of the first derivative of the wavefront and varies with the tilt of the wavefront. For a simple spherical lens, the refractive power Pc is defined as follows: The tilt-based refractive power PS is defined as follows: PC = PS for a simple lens (with paraxial assumptions). The radial refractive power is the refractive power in a direction extending radially outward from the center of curvature of the lens. The circumferential refractive power is the refractive power in a constant radial coordinate extending around the circumference of the lens. The mean curvature is the average of the radial and circumferential refractive powers. The radial-sagittal refractive power is the sagittal refractive power in a direction extending radially outward from the center of the lens. The circumferential sagittal refractive power is the sagittal refractive power at a constant radial coordinate, extending around the circumference of the lens. The central area may have a curvature refractive power identical to the sagittal refractive power. This is referred to here as the base curvature refractive power, base sagittal refractive power, or base refractive power. The nominal refractive power of the central area corresponds to the refractive power stated on the contact lens packaging (although it may not be the same value in practice). This is the average sagittal refractive power or the average curvature refractive power in the central area. The measured refractive power of the central area is the directly measured mean curvature refractive power or sagittal refractive power across the central area. This may differ from the nominal refractive power. In lenses used to treat myopia, the base power is negative or close to zero, and the central area corrects distance vision. The base power can range from 0.5 diopters (D) to -15.0 diopters. The base power can range from -0.25 D to -15.0 D. The base refractive power of the central region can result from the curvature of a lens surface. This base refractive power can arise from the curvature of an anterior surface of the lens and / or the center of curvature of a posterior surface of the lens. In the context of the present disclosure, the annular region is an essentially ring-shaped region that surrounds the optical zone. It may have an essentially circular or an essentially elliptical shape. It may completely enclose the optical zone. It may partially enclose the optical zone. In embodiments of the present disclosure, the radial curvature refractive force of the annular region is greater than the base radial curvature refractive force of the central region. The radial refractive power of the annular region can be determined by the curvature of at least one surface of the annular region. The radial refractive power of the annular region can result from the curvature of a front surface and / or a rear surface of the lens. The annular region can have a greater curvature or a smaller radius of curvature than the central region. The front surface of the annular region can have a greater curvature or a smaller radius of curvature than the curvature of the central region. Alternatively or additionally, the rear surface of the annular region can have a greater curvature than the curvature of the central region. The radial curvature refractive power can vary over the annular region. At a point halfway across the width of the annular region, the radial curvature refractive power of the annular region is X. The radial curvature refractive power is more positive (or less negative) than the base radial curvature refractive power. The net radial curvature refractive power of the annular region is the sum of the base radial curvature refractive power of the central region and the radial addition curvature refractive power of the annular region. For example, if the base radial curvature refractive power is -3.0D and the radial addition curvature refractive power of the annular region is +4.0D, then the net radial curvature refractive power of the annular region is +1.0D. The value of X can range between +0.5 and +20.0 D. The value of X can be +10.0 D greater than the basic radial curvature refractive power (i.e., the radial curvature addition refractive power at a point in the middle of the width of the annular region can be +10.0 D). The value of X can be +11.0 D greater than the basic radial curvature refractive power (i.e., the radial curvature addition refractive power at a point in the middle of the width of the annular region can be +11.0 D). The value of X can be +12.0 D greater than the basic radial curvature refractive power (i.e., the radial curvature addition refractive power at a point in the middle of the width of the annular region can be +12.0 D). The annular region can be understood as being inclined relative to the central region. In this case, the inclination of the annular region is circularly symmetrical, not lateral. The annular region is inclined along a curve that extends around the circumference of the lens, such that the outer edge of the annular region moves in a first direction and the inner edge of the annular region moves in the opposite direction. Due to the inclination of the annular region, its radial-sagittal refractive power changes, as this is a function of the first derivative of the wavefront, but not its radial-curvature refractive power, which is a function of the second derivative of the wavefront.An inclination of the annular region relative to the central region means that the center of curvature of the annular region is displaced by a first distance from the first optical axis of the central region. The radial-sagittal refractive power of the annular region can vary across the width of the annular region and in embodiments of the present disclosure. At a point at mid-width of the annular region, the radial-sagittal refractive power of the annular region is Y. Y is greater than the base radial-sagittal refractive power of the central region, but Y is less than X (the radial curvature refractive power of the annular region at a point at mid-width of the annular region). The radial-sagittal refractive power of the annular region will be more positive than the sagittal refractive power of the central region.The net radial-sagittal refractive power of the annular region is the sum of the radial base sagittal refractive power and the radial-sagittal addition refractive power of the annular region. The value of Y can range from +0.5 to +10.0 D. The value of Y can be +2.0 D greater than the base radial-sagittal refractive power (i.e., the radial-sagittal addition refractive power at a point halfway across the width of the annular region can be +2.0 D). The value of Y can be +4.0 D greater than the base radial-sagittal refractive power (i.e., the radial-sagittal addition refractive power at a point at the midpoint of the width of the annular region can be +4.0 D). The value of Y can be +3.0 D greater than the base radial-sagittal refractive power (i.e., the radial-sagittal addition refractive power at a point in the middle of the width of the annular region can be +3.0 D). Exemplary combinations of values ​​for X and Y are described below. The person skilled in the art will immediately understand that many other combinations of X and Y values ​​fall within the scope of this disclosure. The value of X can be +10.0 D greater than the basic radial curvature refractive power (i.e., the radial curvature addition refractive power at a point halfway across the annular region can be +10.0 D), and the value of Y can be +2.0 D greater than the basic radial sagittal refractive power (i.e., the radial sagittal addition refractive power at a point halfway across the annular region can be +2.0 D). The value of X can be +12.0 D greater than the basic radial curvature refractive power (i.e., the radial curvature addition refractive power at a point halfway across the annular region can be +12.0 D), and the value of Y can be +4.0 D greater than the basic radial sagittal refractive power (i.e., the radial sagittal addition refractive power at a point halfway across the annular region can be +4.0 D). The value of X can be +10.0 D greater than the basic radial curvature refractive power (i.e., the radial curvature addition refractive power at a point halfway across the annular region can be +10.0 D), and the value of Y can be +3.0 D greater than the basic radial sagittal refractive power (i.e., the radial sagittal addition refractive power at a point halfway across the annular region can be +3.0 D). The value of X can be +11.0 D greater than the basic radial curvature refractive power (i.e., the radial curvature addition refractive power at a point halfway across the annular region can be +11.0 D), and the value of Y can be +3.0 D greater than the basic radial sagittal refractive power (i.e., the radial sagittal addition refractive power at a point halfway across the annular region can be +3.0 D). The value of X can be +12.0 D greater than the basic radial curvature refractive power (i.e., the radial curvature addition refractive power at a point halfway across the annular region can be +12.0 D), and the value of Y can be +3.0 D greater than the basic radial sagittal refractive power (i.e., the radial sagittal addition refractive power at a point halfway across the annular region can be +3.0 D). The radial refractive power of the annular region can be greater than the circumferential refractive power of the annular region. The circumferential refractive power of the annular region can be the same as the base circumferential refractive power. The circumferential sagittal refractive power of the annular region can be identical to the base circumferential sagittal refractive power. The radial-sagittal refractive power of the annular region can be greater than the radial-sagittal refractive power of the central region across the width of the annular region. In known center-spaced lens designs that have an annular region providing an additive refractive power, where the center of curvature of the annular region coincides with the optical axis of the central region (this can be referred to as the axial annular region), the radial-sagittal refractive power of the annular region is greater than the radial-sagittal refractive power of the central region across the width of the annular region.In known center-spaced lens designs featuring an annular region that provides additive refractive power, where the center of curvature of the annular region is offset from the optical axis of the central region (this can be referred to as an off-axis annular region), the radial-sagittal refractive power of the annular region may be less than that of the central region at its innermost edge due to an inclination of the annular region relative to the central region. The radial-sagittal refractive power may increase with increasing radial distance towards the outer edge of the annular region.In these known designs, the annular region can be radially inclined relative to the central region such that the radial sagittal refractive power at the center of the annular region's width corresponds to the radial sagittal refractive power the central region would have if it were extended to that center. The lens can have a radial sagittal refractive power at the center of the annular region that corresponds to the radial sagittal refractive power the central region would have if it were extended to that center. The combined effect of an annular region inclined relative to the central region and a small radius of curvature of the annular region means that the radial-sagittal refractive power of the annular region can be greater than the radial-sagittal refractive power of the central region across the entire width of the annular region. Alternatively, the sagittal refractive power of the annular region can decrease at the boundary between the central region and the annular region. The radial-sagittal refractive power can increase radially outwards across the width of the annular zone. The increase in the radial-sagittal refractive power radially outwards from the innermost edge of the annular zone can be a linear increase. The radial curvature refractive force can be constant radially outward from the inner edge of the annular area along a given meridian, or it can increase radially outward from the inner edge of the annular area along a given meridian. The radial curvature refractive power can vary around the meridian of the annular region between a minimum value X1 and a maximum value X2, where both X1 and X2 are greater than the base radial curvature refractive power. Both X1 and X2 can be greater than the base radial curvature refractive power. The radial curvature refractive power can vary periodically around the annular region. The variation can be defined by a sine, triangular, rectangular, or sawtooth waveform. The radial curvature refractive power can vary continuously between X1 and X2. If the position around the circumference of the annular region is defined by an angle θ, where θ varies between 0° and 360°, there can be a maximum of the radial curvature refractive power every 90°, every 45°, every 20°, or every 10°. X1 can be between +0.5D and +10.0D. X2 can range between +2.0 D and +20.0 D. Alternatively or additionally, the radial-sagittal refractive power of the annular region can vary around the meridian between a maximum value Y1 and a minimum value Y2, where both Y1 and Y2 are greater than the base radial-sagittal refractive power. Both Y1 and Y2 can be greater than the base radial-sagittal refractive power. The radial-sagittal refractive power can vary periodically around the annular region. This periodic variation can occur around the entire annular region or around a portion of it. The variation can be defined by a sinusoidal waveform, a triangular waveform, or a sawtooth waveform. The radial-sagittal refractive power can vary continuously between Y1 and Y2.If the position around the circumference of the annular region is defined by an angle θ, where θ varies between 0° and 360°, the maximum radial-sagittal refractive power can occur every 90°, every 45°, every 20°, or every 10°. Y1 can range between +0.5 and +9.0 D. Y2 can range between +2.0 and +19.0 D. In embodiments of the present disclosure in which the radial curvature refractive power of the annular region varies between a minimum value X1 and a maximum value X2, both X1 and X2 can be greater than Y. In embodiments of the present disclosure in which the radial sagittal refractive power of the annular region varies between a minimum value Y1 and a maximum value Y2, both Y1 and Y2 can be less than X. In embodiments of the present disclosure in which the radial curvature refractive power of the annular region varies between a minimum value X1 and a maximum value X2, and the radial sagittal refractive power of the annular region varies between a minimum value Y1 and a maximum value Y2, the changes in the radial curvature refractive power and the radial sagittal refractive power can be in phase or out of phase.In each meridian around the annular region, the radial refractive power can be greater than the radial-sagittal refractive power. Both the radial-sagittal refractive power and the radius of curvature of the annular region can vary with the meridian around the annular region such that the radial refractive power of the lens remains constant or changes approximately constantly around the annular region. For example, in a lens with a constant radial refractive power of +3.0 D, the radial-sagittal refractive power can vary between +2.0 D and +3.0 D with the meridian around the annular region. In regions with a radial-sagittal refractive power of +3.0 D, the radius of curvature of the annular region is centered on the first optical axis.In areas with a radial-sagittal refractive power of +2.0 D, the center of curvature of the ring-shaped area shifts away from the first optical axis, and the radius of curvature of the ring-shaped area may change. The contact lens can comprise at least two concentric annular regions. For each of the at least two annular regions, the annular region can have a radial curvature refractive power of X at a point at mid-width of the annular region, where X is greater than the base radial curvature refractive power. Each of the at least two annular regions can have an off-axis center of curvature located at a first distance from the optical axis, such that the annular region has a radial-sagittal refractive power of Y at a point at mid-width, where Y is greater than the base radial-sagittal refractive power and where Y is less than X. Each annular region can exhibit any of the annular region features described above.In embodiments with at least two concentric annular regions, each annular region can have the same radial curvature refractive power profile and the same radial sagittal refractive power profile, or each concentric annular region can have a different radial curvature refractive power profile and / or radial sagittal refractive power profile. In embodiments with at least two concentric annular regions, the annular regions can be separated by a region with the base refractive power (i.e., with the same refractive power as the central region). The contact lens may comprise an elastomer material, a silicone elastomer material, a hydrogel material, a silicone hydrogel material, or combinations thereof. In the context of contact lenses, a hydrogel is understood to be a material that retains water in an equilibrium state and is free of any silicone-containing chemical. A silicone hydrogel is a hydrogel that contains a silicone-containing chemical. Hydrogel materials and silicone hydrogel materials, as described in connection with the present disclosure, have an equilibrium water content (EWC) of at least 10% to about 90% (wt / wt). In some embodiments, the hydrogel material or silicone hydrogel material has an EWC of about 30% to about 70% (wt / wt). In comparison, a silicone elastomer material, as described in connection with the present disclosure, has a water content of about 0% to less than 10% (wt / wt).Typically, the silicone elastomer materials used with the present methods or devices have a water content of 0.1% to 3% (wt / wt). Examples of suitable lens formulations are those with the following United States Adopted Names (USANs): 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, 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. Alternatively, the lens may have a silicone elastomer material, consist substantially of it, or be made entirely of it. For example, the lens may have a silicone elastomer material with a Shore A hardness of 3 to 50, consist substantially of it, or be made entirely of it. The Shore A hardness can be determined using conventional methods understood by experts (for example, using a method according to DIN 53505). Other silicone elastomer materials can be obtained, for example, from NuSil Technology or Dow Chemical Company. According to a second aspect, the present disclosure provides a method for manufacturing a lens. The method may include forming a contact lens, wherein the contact lens has a central region, the central region having a first optical axis, a base curvature refractive power, and a base sagittal refractive power, and being centered on a center of curvature lying on the first optical axis. The lens has an annular region. The annular region has a radial curvature refractive power of X, which is greater than the base radial curvature refractive power. The annular region has an off-axis center of curvature located at a first distance from the optical axis, such that the annular region has a radial sagittal refractive power of Y at a point at mid-width, where Y is greater than the base radial sagittal refractive power and less than X. The lens can have any of the above-mentioned characteristics. The manufacturing process can include forming a female mold part with a concave lens-forming surface and a male mold part with a convex lens-forming surface. The process can include filling a gap between the female and male mold parts with a lens material. The process can further include curing the lens material to form the lens. The contact lens can be shaped by turning. The lens can be formed by casting, centrifugal casting, turning, or a combination thereof. As experts understand it, casting refers to shaping a lens by inserting a lens-forming material between a female mold part with a concave lens-forming surface and a male mold part with a convex lens-forming surface. The method for manufacturing a lens may include designing a contact lens, wherein the designed lens is a lens according to an embodiment of the present disclosure and has one of the features described above. The lens may be designed using a model, which may be a computer-implemented model. The method may include the modeling of a first contact lens. The first contact lens may have a central region, wherein the central region has a first optical axis. The central region may have a base refractive power and be centered on a center of curvature that lies on a first optical axis. The first contact lens may have an annular region surrounding the central region. The annular region may have a radius of curvature centered on the first optical axis, wherein the curvature of the annular region results in an additive refractive power, the net refractive power of the annular region being the sum of the base refractive power and the additive refractive power. The method may include the modeling of a second contact lens. The second contact lens may have the same central region as the first contact lens.The central area of ​​the second lens can have the same base refractive power as the first lens and can be centered on a center of curvature that lies on a first optical axis. The second contact lens can have an annular area surrounding the central area. This annular area can have a radius of curvature centered on the first optical axis, and the curvature of this annular area can result in an additive refractive power greater than that of the first contact lens. The net refractive power of the second lens is the sum of its base refractive power and additive refractive power. The net refractive power of the second lens can be greater than that of the first lens.The lens design process can involve tilting the annular region of the second lens within the model, such that the outer circumference or edge of the annular region coincides with the outer edge of the annular region of the first lens, while the inner edge of the annular region remains fixed. Tilting the annular region of the second lens shifts the center of curvature of the annular region away from the first optical axis. This tilting of the annular region of the second lens results in a third modeled lens, i.e., the tilted second lens. The third lens, or the tilted second lens, has an annular region with the same net refractive power as the untilted second contact lens, but with an off-axis center of curvature. The process for manufacturing a lens may involve producing a lens based on the modeled third contact lens (i.e., the inclined second lens). Because a lens based on the third modeled lens has a higher curvature than a lens based on the first modeled lens, it may exhibit higher positive spherical aberration. A lens manufactured based on the third contact lens design may also have a greater depth of field than a lens based on either the first or second modeled lens. Fig. 1A shows a schematic top view of a contact lens 1 that uses a treatment zone providing a myopically defocused image to reduce the progression of myopia. Fig. 1B shows a schematic side view of the lens 1 from Fig. 1A. The lens 1 has an optical area 2 that approximately covers the pupil and a peripheral area 4 that lies over the iris. The peripheral area 4 performs mechanical functions, such as magnifying the lens, making the lens 1 easier to handle, providing ballast to prevent rotation of the lens 1, and providing a contoured area that improves comfort for the wearer of the lens 1. The optical zone 2 provides the optical functionality of the lens 1 and has an annular area 3 and a central area 5. The lens 1 has a base radial curvature power equal to its base radial sagittal power.The base refractive power results from the radius of curvature of a surface of the lens 1. The center of curvature of the central region 5 lies on a first optical axis 19 (shown in Fig. 2A). The annular region 3 has a greater radial refractive power than the base radial refractive power. The radial refractive power of the annular region 3 is provided by a radius of curvature 6 of the annular region 3 that is smaller than the radius of curvature 7 of the central region 5, as shown in Fig. 3. The center of curvature of the annular region 3 lies on the first optical axis 19. The annular region 3 has a greater refractive power than the central region 5. As shown in Fig. 2A, the focal point 11 of the annular region 3 and the focal point 15 of the central region 5 share a common optical axis 19.The focal point 11 of the annular region 3 lies on a proximal focal surface 13, and the focal point of the central region 5 lies on a distal focal surface 17, which is further away from the rear surface of the lens. As shown in Fig. 2C, the light rays focused through the central region 5 form a focused image 23 at the distal focal surface 17 when the point source is at infinity. Light rays focused through the central region 5 also produce a blurred point 27 at the proximal focal surface 13. As shown in Fig. 2B, the light rays focused by the annular region 3 form a focused image 21 at the proximal focal surface 13. The light rays focused by the annular region 3 diverge after the proximal focal surface 13, and the diverging light rays produce an unfocused ring 25 at the distal focal surface 17. As already mentioned, the blurred ring image 25 can cause the wearer of the lens 1 to see a "halo" around the focused distance image. Fig. 4A is a diagram 31 showing the variation of the radial-sagittal refractive power for the lens 1 shown in Fig. 1A and Fig. 1B, and Fig. 4B is a diagram 33 showing the variation of the radial-curvature refractive power for the lens 1 shown in Fig. 1A and Fig. 1B. Fig. 4A and Fig. 4B show changes in refractive power along a radial diameter of the lens 1. Since, in this lens 1, the annular region 3 has a greater refractive power than the central region 5, and the annular region 3 has a center of curvature close to the axis, the radial-sagittal refractive power (indicated by curve 35) is greater in the annular region 3 than in the central region 5. The radial-curvature refractive power (indicated by curve 37) is also greater over the annular region 3 than over the central region 5. Fig. 5A shows a schematic top view of another contact lens 101 with non-coaxial optics. Fig. 5B is a schematic side view of the lens 101 from Fig. 5A. Similar to the lens 1 from Fig. 1A, the lens 101 has an optical area 102 that approximately covers the pupil and a peripheral area 104 that sits above the iris. The peripheral area 104 performs mechanical functions, including magnifying the lens, which makes the lens 101 easier to handle; it provides ballast to prevent rotation of the lens 101; and it provides a contoured area that improves comfort for the wearer of the lens 101. The optical area 102 provides the optical functionality of the lens 101 and has an annular area 103 and a central area 105. Lens 101 has a base radial curvature refractive power that is equal to the base radial sagittal refractive power.The base refractive power results from the radius of curvature of a surface of the lens 101. The center of curvature of the central region 105 lies on a first optical axis 119 (shown in Fig. 6A). The annular region 103 has a greater radial refractive power than the base radial refractive power. The radial refractive power of the annular region 103 is provided by a radius of curvature of the annular region 103 that is smaller than the radius of curvature of the central region 105. However, unlike the lens 1 of Fig. 1A and Fig. 1B, in the lens 101 shown in Fig. 5A and Fig. 5B, the curvature of the annular region 103 cannot be defined by a single sphere, and a center of curvature of the annular region 103 does not lie on the first optical axis 119. This is illustrated in Fig. 6D.The annular region 103 is inclined relative to the central region 105, such that the outer edge of the annular region 103 (in Fig. 5B) is higher relative to its inner edge than in the lens 1 of Fig. 1A and Fig. 1B, which changes the radial-sagittal refractive power of the annular region 103, but not the radial-curvature refractive power of the annular region 103. As shown in Fig. 6D, the front surface of the central region 105 defines part of the surface of a sphere with a larger radius 107. The front surface of the annular region 103 defines a curved annular surface with a smaller radius 106. At the distal focal surface 117, the light rays passing through the central area 105 are focused. The annular area 103 acts as an optical diaphragm, resulting in a small spot 133 of light 124 at the distal focal surface 117, as shown in Fig. 6C. No single image is produced at the proximal focal surface 113. As shown in Fig. 6B, light rays passing through the central region 105 produce a circle of confusion 128 at the proximal focal surface 113 for a point source at infinity, just as the lens in Figs. 1A, 1B and 2A, 2B does. However, light rays from a distant point source passing through the annular region 103 produce a focused ring 122, as shown in Fig. 6B, surrounding the circle of confusion 128. Fig. 6B shows the light pattern produced for a distant point source. In contrast to lens 1 of Fig. 1A and Fig. 1B, lens 101 of Fig. 5A and Fig. 5B does not produce a single image or an axial image at the proximal focal surface 113 that could be used to avoid the need for the eye to accommodate to near objects.For an extended object at a distance, the focused image formed at the proximal focal surface 113 is a superposition of (i) the focused image of the extended object that would be obtained with a conventional lens having the optical refractive power of the annular region 103, and (ii) an optical transfer function representing the optical action of the annular region 103. In contrast to lens 1 of Fig. 1A and Fig. 1B, no ring or "halo" effect occurs at the distal focal surface 117. Fig. 7A is a diagram 131 showing the variation of the radial-sagittal refractive power for the lens 101 shown in Fig. 5A and Fig. 5B, and Fig. 7B is a diagram 133 showing the variation of the radial curvature-based refractive power for the lens shown in Fig. 5A and Fig. 5B. Fig. 7A and Fig. 7B show variations in refractive power along a radial diameter of the lens 101. In this lens 101, the annular region 103 has a greater refractive power than the central region 105, which means that the radial curvature refractive power (indicated by curve 137) is greater in the annular region 103 than in the central region 105. However, the annular region 103 is inclined relative to the central region 105, so that the annular region 103 has an off-axis center of curvature.The inclination of the annular region 103 relative to the central region 105 means that the radial-sagittal refractive power at the boundary between the central region 105 and the annular region 105 is more negative than the radial-sagittal refractive power of the central region, as shown by curve 135. The radial-sagittal refractive power can increase with increasing radial distance towards the outer edge of the annular region 103. Fig. 8A shows a schematic top view of a contact lens 201 according to an embodiment of the present disclosure. Similar to the lens 1 of Fig. 1A and Fig. 1B and the lens 101 of Fig. 5A and Fig. 5B, the lens 201 has an optical area 202 that approximately covers the pupil and a peripheral area 204 that sits above the iris. The peripheral area 204 performs mechanical functions, including magnifying the lens, which makes the lens 201 easier to handle; it acts as ballast to prevent rotation of the lens 201; and it provides a contoured area that improves comfort for the wearer of the lens 201. The optical area 202 provides the optical functionality of the lens 201 and has an annular area 203 and a central area 205. The central area 205 of the lens 201 has a base radial curvature refractive power that is equal to the base radial sagittal refractive power.In this exemplary embodiment of the present disclosure, the base radial refractive power of the central region is 0.0 D, which corresponds to the base radial sagittal refractive power of the central region 205. This base refractive power results from the radius of curvature of a surface of the lens 201. The center of curvature 244 of the central region 205 lies on a first optical axis 219 (shown in Fig. 9). The annular region 203 has a greater radial refractive power than the base radial refractive power. The radial refractive power of the annular region 203 is provided by a radius of curvature of the annular region 203 that is smaller than the radius of curvature of the central region 205. At a point A at half the width of the annular region (shown in Fig. 8A and Fig. 8B), the radial curvature refractive power of the annular region has a value of approximately +3.5 D. In the example lens 201 shown in Fig. 8A and Fig. 8B, the radial curvature refractive power is constant at a given radial position in all meridians around the annular region 203. This means that the radial curvature refractive power has the same value at a point at half the width of the annular region 203 along the dashed curve 241 shown in Fig. 8A and Fig. 8B, a curve that extends around the annular region 203. In this embodiment of the present disclosure, X is approximately +3.5 D. Similar to the example lens 201 shown in Fig. 5A and Fig. 8B, the radial curvature refractive power is approximately +3.5 D.In the lens shown in Figure 5B, the annular region 203 of the lens 201 is inclined relative to the central region 205, such that a center of curvature 243 of the annular region 203 is offset from the first optical axis 219. This is illustrated in Figure 9. The inclination of the annular region 203 relative to the central region 205 reduces the radial-sagittal refractive power at the boundary between the central region 205 and the annular region 203. At point A, located at mid-width of the annular region 203, the radial-sagittal refractive power has a value Y that is greater than the base radial-sagittal refractive power but less than X. In this embodiment, Y is approximately +2.25D, and the radial-sagittal refractive power is constant in all meridians around the annular region 203 for a given radial position. This means that the radial-sagittal refractive power along the line shown in Fig. 8A and Fig.The dashed curve 241 shown in 8B, a curve that extends around the ring-shaped area 203, has the same value. In a distal focal plane 217, the light rays passing through the central region 205 are focused. Light rays passing through the annular region 203 are directed onto a sagittal additional focal plane 218. Fig. 10A is a diagram 231 showing the variation of the refractive force over a radial diameter of the lens 201 shown in Fig. 8A and Fig. 8B. This diagram 231 shows the mean value of the radial and circumferential refractive force. In the central region 205, the refractive force of the lens 201 is constant and approximately zero. At the boundary between the central region 205 and the annular region 203, the refractive force increases sharply, as can be seen from the curve 235. This is due to an increase in the radial refractive force. The circumferential curvature refractive power does not change significantly at the boundary between the central region 205 and the annular region 203, but the radial curvature refractive power increases, so that the average curvature refractive power (shown by curve 235) at the boundary between the central region 205 rises to an average of the circumferential curvature refractive power and the radial curvature refractive power.Fig. 10B is a diagram 233 showing the variation of the sagittal refractive force over a radial diameter of the lens 201 shown in Fig. 8A and Fig. 8B. This diagram 233 shows the average of the radial and circumferential sagittal refractive forces. In the central region 205 of the lens 201, the sagittal refractive force is constant and has a value of 0.0 D. At the boundary between the central region 205 and the annular region 203, the sagittal refractive force of the annular region 203 increases sharply due to an increase in the radial sagittal refractive force, as indicated by curve 237. The radial sagittal refractive force increases approximately linearly radially outward across the width of the annular region 203. In contrast to the curve of the sagittal refractive power of a lens with an annular region 203 with off-axis addition refractive power shown in Fig. 7A, there is no decrease in the sagittal refractive power at the boundary between the central region 205 and the annular region 203.This is because the annular region 203 is inclined relative to the central region in such a way that the radial-sagittal refractive power increases at the boundary between the central region 205 and the annular region 203. The increase in sagittal refractive power at the boundary between the central region 205 and the annular region 205 is not as large as in a lens with an annular region having additional refractive power on the axis (for example, as shown in Fig. 1A and Fig. 1B). As shown in Fig. 11A, with the lens 201 depicted in Figs. 8A and 8B, light rays passing through the central region 205 at a distal focal surface 217 produce a focused image 223, as shown in Fig. 11B. Light rays passing through the annular region 203 produce an unfocused ring 225 at the distal focal surface 217. At a first proximal focal plane 218, light rays passing through the central region 205 produce a first circle of confusion 227 for a point source at infinity, and light rays passing through the annular region 203 produce a second circle of confusion 229, as shown in Fig. 11C.At a second proximal focal surface 220, light rays passing through the central region 205 produce a third circle of confusion 231, and light rays passing through the annular region 203 produce a focused ring 233 that lies within the third circle of confusion 231, as shown in Fig. 11D. Fig. 12A shows a schematic top view of a contact lens 301 according to an embodiment of the present disclosure. Similar to the lens 201 in Fig. 8A and Fig. 8B, the lens 301 has an optical region 302 that approximately covers the pupil and a peripheral region 304 that lies above the iris. The peripheral zone 304 fulfills mechanical functions, including magnifying the lens, making the lens 301 easier to handle, it acts as ballast to prevent rotation of the lens 301, and provides a shaped area that improves comfort for the wearer of the lens 301.The optical zone 302 provides the optical functionality of the lens 301, and the optical zone 302 has an annular region 303 and a central region 305. The lens 301 has a base radial refractive power equal to the base radial sagittal refractive power. In this embodiment of the present disclosure, the base radial refractive power of the central region is -2.0 D and the base radial sagittal refractive power of the central region is -2.0 D. The base refractive power results from the radius of curvature of a surface of the lens 301. The center of curvature of the central region 305 lies on a first optical axis. The annular region 303 has a greater radial refractive power than the base radial refractive power. The radial curvature refractive force of the annular region 303 varies with the meridian around the annular region 303.In this embodiment, the radial curvature refractive force is approximately constant when it extends radially outward along any meridian. Along a curve that runs around the annular region 303 at half its width and is indicated by the dashed line 341 in Figs. 12A and 12B, the radial curvature refractive force varies between a minimum value X1 and a maximum value X2. Both X1 and X2 are greater than the base curvature refractive force of the central region 305. X1 is +2.0 D and X2 is +10.0 D. The radial curvature refractive force varies sinusoidally around the annular region, with a profile shown in Fig. 14.If the position around the circumference of the annular region 303 is defined using the angle θ, where θ varies between 0° and 360°, then the radial curvature refractive force for this exemplary embodiment has a maximum value of X2 at a point halfway across the width of the annular region 303 every 180°, such that the radial curvature at points A and C is X2. The radial curvature refractive force has a minimum value of X1 at a point halfway across the width of the annular region 303 every 180°, such that the radial curvature at points B and D is equal to X1. The radial curvature refractive force of the annular region 303 results from the curvature of a surface of the annular region 303. At all points around the annular region 303, the radius of curvature of the annular region 303 is smaller than the radius of curvature 307 of the central region 305. At all points around the annular region 303, the annular region 303 has an off-axis center of curvature. In this embodiment, the radius of curvature of the annular region 303 varies with the meridian, and this leads to the varying radial curvature refractive force. As shown in Fig. 13A, the radius of curvature 306e of the annular region 303 is smallest along a radial diameter where the radial curvature has a maximum value (line EE in Fig. 12A) (Fig. 13A). As shown in Fig.As shown in Fig. 13B, the radius of curvature 306f of the annular region 303 is greatest along a radial diameter where the radial curvature has a minimum value (line FF in Fig. 12A). In this lens 301, the radial-sagittal refractive power at a point halfway across the annular region 303 has a constant value of Y, and Y has a constant value around the annular region 305. Y is smaller than X, but Y is larger than the base refractive power of the central region 305 of the lens 301, as shown schematically in Fig. 14. In other embodiments of the present disclosure (not shown), the lens is similar to the lens shown and described in Figs. 8A-11D, but at a point A at half the width of the annular region (as shown in Figs. 8A and 8B), the radial curvature refractive power of the annular region is about +10.0 D greater than the base radial curvature refractive power of the central region (i.e., the radial curvature addition refractive power is about +10.0 D), and the radial sagittal refractive power of the annular region is about +2.0 D greater than the base radial sagittal refractive power of the central region (i.e., the radial sagittal addition refractive power is about +2.0 D). In other embodiments of the present disclosure (not shown), the lens resembles the lens shown and described in Figures 8A-11D, but at a point A at mid-width of the annular region, the radial curvature refractive power of the annular region is approximately +12.0 D greater than the base radial curvature refractive power of the central region (i.e., the radial curvature addition refractive power is approximately +12.0 D), and the radial sagittal refractive power of the annular region is approximately +4.0 D greater than the base radial sagittal refractive power of the central region (i.e., the radial sagittal addition refractive power is approximately +4.0 D). Advantageously, such a lens exhibits a sharp increase in radial sagittal refractive power at the boundary between the central region and the annular region. The increase in radial sagittal refractive power can be greater than +2.0 D.For a lens wearer with a relatively small pupil diameter (for example, a young lens wearer), this strong increase in radial-sagittal refractive power at the border between the central area and the annular area can improve the treatment effect of the annular area. In other embodiments of the present disclosure (not shown), the lens is similar to the lens shown and described in Figs. 8A-11D, but at a point A at half the width of the annular region (as shown in Figs. 8A and 8B), the radial curvature refractive power of the annular region is about +11.0 D greater than the base radial curvature refractive power of the central region (i.e., the radial curvature addition refractive power is about +11.0 D), and the radial sagittal refractive power of the annular region is +3.0 D greater than the base radial sagittal refractive power of the central region (i.e., the radial sagittal addition refractive power of the annular region is about +3.0 D). In other embodiments of the present disclosure (not shown), the lens is similar to the lens shown and described in Figs. 8A-11D, but at a point A at half the width of the annular region (as shown in Figs. 8A and 8B), the radial curvature refractive power of the annular region is about +12.0 D greater than the base radial curvature refractive power of the central region (i.e., the radial sagittal addition refractive power of the annular region is about +3.0 D). In other embodiments of the present disclosure (not shown), the lens resembles the lens shown and described in Figures 8A-11D, but at a point A at half the width of the annular region (as shown in Figures 8A and 8B), the radial curvature refractive power of the annular region is about +10.0 D greater than the base radial curvature refractive power of the central region (i.e., the radial curvature addition refractive power is about +10.0 D), and the radial sagittal refractive power of the annular region is about +3.0 D greater than the base radial sagittal refractive power of the central region (i.e., the radial sagittal addition refractive power is about +3.0 D). In other embodiments of the present disclosure, lenses may have an annular region with a radial curvature refractive power that varies stepwise or sawtooth-like with the meridian. The variation can be periodic or non-periodic.There can be peak values ​​in the radial refractive power every 180°, every 90°, every 20°, every 10°, or every 5°. Figures 15A-C, for example, show periodic variations in the radial refractive power, which can also be variations in the radial sagittal or curvature refractive power. In other embodiments of the present disclosure, both the radial curvature refractive power and the radial sagittal refractive power can vary with the meridian around the annular region. The variation of the radial sagittal refractive power can be in phase with or out of phase with the variation of the radial curvature refractive power. At all points on the circumference of the annular region, the radial sagittal refractive power can be smaller than the radial curvature refractive power but larger than the base refractive power of the central region. In other embodiments of the present disclosure, the lens may comprise two or more concentric annular regions. For each of the annular regions, the annular region has a radial curvature refractive power of X at a point at mid-width, where X is greater than the base radial curvature refractive power. Each of the at least two annular regions may have an off-axis center of curvature located at a first distance from the optical axis, such that the annular region has a radial-sagittal refractive power of Y at a point at mid-width, where Y is greater than the base radial-sagittal refractive power and where Y is less than X. Each concentric annular region may be separated by a region having the base refractive power (i.e., the same refractive power as the central region). In other embodiments of the present disclosure, the lens may comprise two or more concentric annular regions. At least one of the annular regions is an annular region as shown in Figures 5A and 6A, and for at least one of the other annular regions, the annular region has a radial curvature refractive power of X at a point at mid-width of the annular region, wherein X is greater than the base radial curvature refractive power. Each of the at least two annular regions may have an off-axis center of curvature located at a first distance from the optical axis, such that the annular region has a radial sagittal refractive power of Y at a point at mid-width, wherein Y is greater than the base radial sagittal refractive power and wherein Y is less than X. Fig. 16 shows a method 501 for designing a contact lens, wherein the lens is a lens according to an embodiment of the present disclosure. In a first step 503, the method comprises modeling a first contact lens. The first contact lens has a central region, the central region having a first optical axis. The central region has a base refractive power and is centered on a center of curvature that lies on a first optical axis. In this example, the central region of the first contact lens has a base refractive power of -3.0 D. The first contact lens has an annular region surrounding the central region. The annular region has a radius of curvature centered on the first optical axis. The curvature of the annular region results in an additive refractive power. In this example, the annular region has a curvature that results in an additive refractive power of +2.0 D.The net refractive power of the annular region is the sum of the base refractive power and the additive refractive power, and therefore the net refractive power of the annular region in this example is -1.0 D. In a second step, the procedure involves modeling a second contact lens. The second contact lens has the same central region as the first contact lens, so in this example, the second contact lens has a base refractive power of -3.0 D. The second contact lens is also centered on a center of curvature that lies on the first optical axis. The second contact lens has an annular region surrounding the central region. The annular region of the second lens has a radius of curvature that is also centered on the first optical axis, but the curvature of the annular region results in an additive refractive power that is greater than the additive refractive power of the first lens.In this example, the curvature of the second annular region results in an additive refractive power of +4.0 D. The net refractive power of the second lens is the sum of the base refractive power and the additive refractive power, so in this example, the net refractive power of the second lens is +1.0 D. In a third step, the procedure features a tilting of the annular region of the second lens within the model, such that the outer edge of the second annular region coincides with the outer edge of the annular region of the first lens, while the inner edge of the second annular region remains fixed. In this way, a third lens (corresponding to the tilted second lens) is created, which has an annular region with the same net refractive power as the untilted second lens.In this example, the third lens, or the inclined second lens, has a ring-shaped area with a net refractive power of +1.0 D, but with a center of curvature that is not on the first optical axis. Fig. 17 is a schematic diagram of three modeled lenses 601, 603, 605, which were modeled within the framework of the lens design procedure described above. The three lenses have a common central region 607 with a curvature centered on a first optical axis and providing a base refractive power of -3.0 D. The first lens 601 has an annular region 601a with a curvature that results in an additive refractive power of +2.0 D, so that the net refractive power of the annular region is -1.0 D. The center of curvature of the annular region 601a of the first lens 601 is centered on the first optical axis. The second lens 603 has an annular area 603a which has a curvature that results in an additive refractive power of +4.0 D, so that the net refractive power of the annular area is +1.0 D.The center of curvature of the annular region 603a of the second lens 603 is also centered on the first optical axis. The inner edge of the annular region 601a of the first lens 601 and the inner edge of the annular region 603a of the second lens 603 coincide at a point 607. The third lens 605 is an inclined version of the second lens 603. The annular region 605a of the third lens 605 has a curvature that results in an additive refractive power of +4.0 D and has the same additive refractive power and the same net refractive power as the second lens 603. The inner edge of the annular region 605a of the third lens coincides with the same point 607 as the first lens 601 and the second lens 603, but the outer edge of the annular region 605a of the third lens 605 is inclined so that it coincides at a point 611 with the outer edge of the annular region 601a of the first lens 601.The ring-shaped area 605a of the third lens 605 has a net refractive power of +1.0 D, but its center of curvature is not on the first optical axis. Aspects and embodiments of the invention are now described by means of numbered clauses: Clause 1: Contact lens, wherein the lens includes an optical zone comprising: a central region, the central region having a first optical axis, a base radial refractive power, a base radial sagittal refractive power, and a center of curvature located on the first optical axis; and an annular region, wherein at a point at mid-width of the annular region the annular region has a radial refractive power of X, where X is greater than the base radial refractive power, and the annular region has an off-axis center of curvature located at a first distance from the optical axis, such that at a point at mid-width the annular region has a radial sagittal refractive power of Y, where Y is greater than the base radial sagittal refractive power and where Y is less than X. Clause 2: Contact lens according to Clause 1, wherein the radial-sagittal refractive power of the annular area is greater than the radial-sagittal refractive power of the central area over the width of the annular area. Clause 3: Contact lens according to Clause 1 or Clause 2, wherein the radial-sagittal refractive power of the annular area increases radially outwards over the width of the annular zone. Clause 4: Contact lens according to one of the preceding clauses, where X is between +0.5 D and +20.0 D. Clause 5: Contact lens according to any of the preceding clauses, where Y is between +0.5 D and +10.0 D. Clause 6: Contact lens according to any of the preceding clauses, wherein the radial curvature refractive power varies with the meridian around the ring-shaped area between a minimum value X1 and a maximum value X2. Clause 7: Contact lens according to Clause 6, where both X1 and X2 are greater than the base radial curvature refractive power. Clause 8: Contact lens according to Clause 6 or Clause 7, wherein the radial curvature refractive power varies periodically around the ring-shaped area. Clause 9: Contact lens according to Clause 8, wherein the periodic variation is defined by a sinusoidal waveform, a triangular waveform or a sawtooth waveform. Clause 10: Contact lens according to any of the preceding clauses, wherein the radial-sagittal refractive power of the annular region varies with the meridian around the annular region between a maximum value Y1 and a minimum value Y2. Clause 11: Contact lens according to Clause 10, where both Y1 and Y2 are greater than the base radial sagittal refractive power. Clause 12: Contact lens according to Clause 10 or Clause 11, wherein the radial-sagittal refractive power varies periodically around the ring-shaped area. Clause 13: Contact lens according to Clause 12, wherein the variation is defined by a sinusoidal waveform, a triangular waveform or a sawtooth waveform. Clause 14: Contact lens according to any of the preceding clauses, wherein the base refractive power of the lens is between 0.5 D and -15.0 D. Clause 15: Contact lens according to any of the preceding clauses, wherein the base refractive power of the central area results from a curvature of an anterior surface and / or posterior surface of the lens. Clause 16: Contact lens according to any of the preceding clauses, wherein the radial curvature refractive power of the annular area results from the curvature of an anterior surface and / or posterior surface of the lens. Clause 17: Contact lens according to any of the preceding clauses, wherein the lens comprises an elastomer material, a silicone elastomer material, a hydrogel material or a silicone hydrogel material or mixtures thereof. Clause 18: Contact lens according to any of the preceding clauses, wherein the lens is manufactured by a turning process or a casting process. Clause 19: Method for manufacturing a contact lens, wherein the method comprises: forming a contact lens according to any of the preceding clauses. It will be understood by average experts that the features of these exemplary embodiments can be combined in other embodiments which fall within the scope of the present disclosure. Where in the foregoing description integers or elements are mentioned for which obvious or foreseeable equivalents are known, these equivalents are included here as if they were listed individually. To determine the true scope of the present disclosure, reference should be made to the claims, which should be interpreted as encompassing all such equivalents. The reader will also understand that integers or features of the disclosure described as advantageous, expedient, or the like are optional and do not limit the scope of the independent claims. Furthermore, it is to be understood that while such optional components or features may be of possible benefit in some embodiments of the disclosure, they may be undesirable in other embodiments and may therefore be omitted.

Claims

Contact lens (201), the lens comprising an optical zone (202) comprising: a central region (205), wherein the central region (205) has a first optical axis (219), a base refractive power, a center of curvature (244) located on the first optical axis (219), and a first radius of curvature; and an annular region (203), wherein the annular region (203) is inclined relative to the central region (205) and has a radial curvature addition refractive power greater than the base refractive power, wherein light rays passing through the central region (205) produce a focused image at a distal focal surface (217), and light rays passing through the annular region (203) do not produce a spot of light at the distal focal surface;and wherein the radial-sagittal refractive power (237) increases at a boundary between the central region (205) and the annular region (203) and the radial-sagittal refractive power (237) increases with increasing radial distance to the outer edge of the annular region (203). Contact lens (201) according to claim 1, wherein the increase in radial sagittal refractive power (237) at the boundary between the central region (205) and the annular region (203) is more than +2.0 D. Contact lens (201) according to claim 1 or claim 2, wherein the base refractive power of the central region (205) results from a curvature of an anterior surface and / or posterior surface of the lens (201). Contact lens (201) according to one of the preceding claims, wherein the radial curvature refractive power (235) of the annular region (203) results from the curvature of an anterior surface and / or posterior surface of the lens (201). Contact lens (201) according to one of the preceding claims, wherein the annular region (203) has a radial curvature refractive power (235) at a point in the middle of the radial width of the annular region (203) which is +10.0 D greater than the base refractive power. Contact lens (201) according to claim 1 or one of claims 3 to 5, wherein the annular region (203) has a radial sagittal refractive power (237) at a point in the middle of the radial width of the annular region (203) which is +2.0 D greater than the base refractive power. Contact lens (201) according to one of claims 1 to 4, wherein the annular region (203) has at a point in the middle of the radial width of the annular region (203) a radial sagittal refractive power (237) which is +4.0 D greater than the base refractive power, and a radial curvature refractive power (235) which is +12.0 D greater than the base refractive power. Contact lens (201) according to one of the preceding claims, wherein the base refractive power of the lens (201) is between 0.5 D and -15.0 D. Contact lens (201) according to one of the preceding claims, wherein the lens (201) comprises an elastomer material, a silicone elastomer material, a hydrogel material or a silicone hydrogel material or mixtures thereof. Contact lens (201) according to one of the preceding claims, wherein the lens is manufactured by a turning process or a casting process. Method for manufacturing a contact lens (201), wherein the method comprises: forming a contact lens (201) according to one of the preceding claims by a turning process or a casting process. The method of claim 11, comprising a step of designing the contact lens (501), wherein the design of the contact lens comprises: (a) modeling a first contact lens (601), wherein the first contact lens (601) has: a central region, the central region having a base refractive power and a center of curvature located on a first optical axis; and an annular region (601a) surrounding the central region, the annular region (601a) having a radius of curvature centered on the first optical axis, wherein a curvature of the annular region (601a) results in a first additive refractive power greater than the base refractive power (503);(b) Modeling a second contact lens (603), wherein the second contact lens (603) has the same central area as the first contact lens and an annular area (603a) surrounding the central area, the annular area (603a) having a radius of curvature centered on the optical axis, and the annular area (603a) resulting in a second addition refractive power greater than the first addition refractive power of the first contact lens (505);(c) Tilting the annular region (603a) of the second contact lens (603) within the model such that an outer edge of the annular region (603a) coincides with an outer edge of the annular region (601a) of the first lens (601), thereby producing a third contact lens (605), wherein the annular region (605a) of the third lens (605) has the second addition refractive power of the annular region (603a) of the second contact lens (603), but has a center of curvature that is a first distance from the first optical axis (507). The method of claim 12, comprising the manufacture of a lens based on the modeled third contact lens (605).

Images