Contact lenses and related methods

Abstract

A contact lens (201) comprises an optical zone (202) centered on an optical axis (219) and a peripheral zone (204) surrounding the optical zone (202). A cross-sectional slice of the optical zone (202) taken along a meridian includes a series of consecutive circular arcs (203a-h) having a radial curvature-power profile that increases monotonically with radial distance from the optical axis (219). Light rays from a distant point source passing through the midpoint of each arc (203a-h) converge towards a point (215) on the optical axis, and for each arc (203a-h), light rays from a distant point source passing through the arc (203a-h) converge towards a point (216) at a first distance from the optical axis. A method for designing and manufacturing such a contact lens (201) is also described.

Description

Technical Field

[0001] The present invention relates to contact lenses. The present invention relates particularly (but not exclusively) to contact lenses for slowing the progression of myopia. The present invention relates particularly (but not exclusively) to contact lenses for use by presbyopic individuals. The present invention also relates to methods of manufacturing such lenses and methods of designing such lenses.

Background Art

[0002] Many people, including children and adults, require contact lenses to correct myopia (nearsightedness), and many adults may require lenses to correct presbyopia (a condition in which the ability to focus on nearby objects is impaired due to a decline in accommodation ability with aging).

[0003] A myopic eye focuses incident light from a distant object at a position in front of the retina. As a result, the light converges towards a plane in front of the retina, diverges towards the retina, and is out of focus when it reaches the retina. Conventional lenses for correcting myopia (e.g., spectacle lenses or contact lenses) reduce the convergence of light (in the case of contact lenses) or cause the divergence of the incident light (in the case of spectacles) before the incident light from a distant object reaches the eye, thereby moving the position of the focus onto the retina.

[0004] A presbyopic eye cannot effectively change its shape to focus on nearby objects. For this reason, presbyopic individuals cannot focus on nearby objects. Conventional lenses for correcting presbyopia (e.g., spectacle lenses or contact lenses) include bifocal lenses and progressive lenses, which include regions optimized for viewing near and regions optimized for viewing far. Presbyopia can also be treated using bifocal or multifocal lenses or using monovision lenses (where different prescriptions are provided for each eye, such as a lens for viewing far in one eye and a lens for viewing near in the other eye).

[0005] Decades ago, it was proposed that the progression of myopia in children and young people could be slowed or prevented by undercorrection, i.e., bringing the focus closer to the retina but not all the way onto the retina. However, this approach necessarily results in a reduction in distance vision compared to the visual acuity obtained with lenses that fully correct myopia. Furthermore, it is now considered doubtful that undercorrection is effective in controlling the progression of myopia. A more recent approach to correcting myopia is to provide a lens that has both one or more regions that provide full correction of distance vision and one or more regions that provide undercorrection, i.e., intentionally induce myopic defocus. This approach has been suggested to be able to prevent or slow the onset or progression of myopia in children and young people while providing good distance vision. In the case of a lens having a region that provides defocus, the region that provides full correction of distance vision is typically referred to as the base refractive power region, and the region that provides undercorrection or intentionally induces myopic defocus is typically referred to as the myopic defocus region or additional refractive power region (the refractive power being more positive or less negative than the refractive power (diopter) of the distant region).

[0006] The surface (typically the front surface) of the additional refractive power region has a radius of curvature smaller than the radius of curvature of the distant refractive power region and thus provides the eye with a more positive or less negative refractive power (diopter). The additional refractive power region is designed to focus incoming parallel light (i.e., light from far away) into the eye in front of the retina (i.e., closer to the lens). The distant refractive power region is designed to focus light to form an image on the retina (i.e., pass through more from the lens).

[0007] Known types of contact lenses that reduce the progression of myopia are bifocal contact lenses available under the name MISIGHT (CooperVision, Inc.). This bifocal lens is configured with a given optical dimension that provides the use of distance correction (i.e., base refractive power) to see both distant and near objects, unlike bifocal or multifocal contact lenses configured to improve presbyopic vision. The treatment zone of the bifocal lens with additional refractive power provides a myopic defocused image at both far and near viewing distances.

[0008] These lenses have been found to be beneficial in preventing or delaying the onset or progression of myopia, but the annular additional refractive power region can cause unwanted visual side effects. Light focused by the annular additional refractive power region in front of the retina diverges from the focus and forms a defocused (blurred) ring on the retina. Thus, wearers of these lenses may see a ring or "halo" around the image formed on the retina, especially in the case of small and bright objects such as streetlights and car headlights. Also, instead of using the eye's natural accommodation (i.e., the natural ability of the eye to change the focal length) to focus on near objects, theoretically, the wearer may utilize the additional focus in front of the retina resulting from the annular additional refractive power region to focus on near objects. This means, in other words, that the wearer may unconsciously (without awareness) use the lens in the same manner as when a presbyopia-correcting lens is used, which is undesirable for young subjects.

[0009] It has been recognized that it may be beneficial to provide lenses that introduce additional myopic defocus for the treatment of myopia. It may be beneficial to provide lenses that expand the depth of focus for the treatment of presbyopia. The present disclosure aims to provide an improved lens that introduces additional myopic defocus and receives the benefits of improved image quality enabled by off-axis imaging techniques as described above. SUMMARY OF THE INVENTION

[0010] According to a first aspect, the present disclosure provides a contact lens comprising an optical zone centered on the optical axis and a peripheral zone surrounding the optical zone. A cross-sectional slice of the optical zone taken along a meridian has a radial curvature refractive power profile that monotonically increases with the radial distance from the optical axis, the cross-sectional slice comprising a plurality of successive continuous Curve including. For each Curve a plurality of light rays from a distant point source passing through the midpoint of are converging towards a single point on the first optical axis. For each Curve for which, the plurality of light rays passing through said Curve converge towards a point at a first distance from the optical axis.

[0011] According to a second aspect, the present disclosure provides a method of manufacturing a lens. The method comprises the step of forming a lens according to the first aspect of the invention.

[0012] According to a third aspect, the present disclosure provides a method of designing a contact lens. The method comprises the step of modeling a contact lens, the lens including an optical zone centered on the optical axis and a peripheral zone surrounding the optical zone. A cross-sectional slice of the optical zone taken along a meridian has a radial curvature refractive power profile that monotonically increases with the radial distance from the optical axis. The method further comprises, within the model, dividing the cross-sectional slice of the optical zone into a plurality of successive continuous Curve starting from a central Curve centered on the optical axis and spreading radially outwards. The method further comprises, within the model, tilting each Curve in said plurality of successive continuous Curve about the midpoint of said Curve such that a plurality of light rays from a distant point source passing through the midpoint of each Curve converge towards a single point on the optical axis, while for each Curve for which said CurveA step is provided in which a plurality of light rays passing through are converged toward a point at a first distance from the optical axis. The method further comprises a step of designing a lens based on the modeled lens.

[0013] Of course, it will be understood that features described in connection with one aspect of the present disclosure may be incorporated into other aspects of the present disclosure. For example, the methods of the present disclosure may incorporate features described with reference to the apparatus of the present disclosure, and vice versa.

[0014] Here, with reference to the accompanying schematic diagrams, embodiments of the present invention are described for illustrative purposes only.

Brief Description of the Drawings

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[0038] In a first aspect, the present disclosure provides a contact lens. The lens includes an optical zone centered on the optical axis and a peripheral zone surrounding the optical zone. A cross-sectional slice of the optical zone taken along a meridian has a series of continuous pluralities having a radial curvature refractive power profile that monotonically increases with the radial distance from the optical axis Curve including. A plurality of light rays from a distant point source passing through the midpoint of each Curve converge towards a single point on the first optical axis. For each Curve the plurality of light rays passing through the Curve converge towards a point at a first distance from the optical axis.

[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 will be understood that such contact lenses provide clinically acceptable on-eye movement and do not adhere to the human eye. 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. The lens can be a lens used to prevent or delay the onset or progression of myopia, and the lens can also be one used to provide an extended depth of focus for myopic eyes.

[0040] The contact lens according to the present disclosure includes an optical zone. The optical zone includes a lens portion having an optical function. The optical zone is configured to be positioned on the pupil of the eye during use. The optical zone is centered on the optical axis. The optical axis may exist along the center line of the lens. A series of continuous plural Curve In addition, a center having a constant radial curvature refractive power Curve can be centered on the optical axis. Alternatively, two central Curve portions having a constant radial curvature refractive power may extend in opposite directions (opposite directions) outward from the optical axis. The lens may include a central region centered on the optical axis, and the central Curve or plural central Curve portions may exist along the diameter of the central region. The central region of the lens is the region straddling the central Curve or central Curve portion, but can focus light from a distant point object onto a spot on the first optical axis at a distal focal plane on the first optical axis. As used herein, the term "plane" does not refer to a physical surface, but to a plane that can be drawn through the point at which light from a distant object is focused. Such a plane is also called an image plane (which may be a curved surface) or an image shell. The eye focuses light on a curved retina. In a perfectly focused eye, the curvature of the image shell matches the curvature of the retina. Thus, the eye does not focus light onto a flat mathematical plane. Nevertheless, in the art, the curved surface of the retina is generally referred to as a (flat) plane.

[0041] In the context of the present disclosure, a series of plural Curve refers to plural Curve that are connected end to end and arranged in series. In the context of the present disclosure, the plural Curve represents a 2D (two-dimensional) slice taken along the meridian of a 3D (three-dimensional) lens. There may be a transition portion connecting each Curve . Each Curve in a series of plural Curvecan be inclined with respect to the center around the midpoint (mid-length point) of its length. A plurality of a series of Curve can be inclined with respect to the center. In a plurality of Curve in the series, the curvature of the plurality of Curve increases monotonically as the distance from the optical axis increases. Therefore, considering the lens in 3D, the curvature in the radial direction of the lens increases monotonically as the radial distance from the optical axis increases.

[0042] Considering all Curve in the series, a plurality of light rays from a distant point light source passing through the midpoint of each Curve converge at a point on the first optical axis. The point coincides with the spot formed by the light focused along the optical axis.

[0043] Considering a single Curve along a given meridian, a plurality of light rays from a distant point light source passing through the single Curve do not converge at a point on the optical axis. A plurality of light rays passing through the single Curve converge at a point at a first distance from the optical axis (the focal point of the Curve ). The first distance is a non-zero distance. This is the result of the relative inclination of the Curve around the midpoint of the length of the Curve . The distance from the optical axis will depend on the center of the lens or the radial distance of the Curve from the optical axis. In the case of a Curve close to the center of the lens, the point at which a plurality of light rays passing through the Curve converge will be closer to the optical axis in the radial direction than in the case of a Curve far from the center of the lens. A plurality of light rays passing through the single Curve converge at a point in front of the distal focal plane (i.e., on the side closer to the lens).

[0044] The lens can be centered on the optical axis and have a central region spanning the central Curve . The central region can have a substantially circular shape and can have a diameter of about 2 mm to about 9 mm, preferably 2 to 7 mm. The central region may have a substantially elliptical shape.

[0045] The optical zone can be surrounded by a peripheral zone. The peripheral zone is not part of the optical zone but is located above the iris outside the optical zone when the lens is worn and provides mechanical functions such as, for example, increasing the size of the lens to make the lens easier to handle, providing a ballast to prevent rotation of the lens, and / or providing a shaped area to improve the comfort of the lens wearer. The peripheral zone can extend to the edge of the contact lens.

[0046] A contact lens according to an embodiment of the present disclosure can include a ballast for orienting the lens when positioned on the wearer's eye. Embodiments of the present disclosure incorporating a ballast into the contact lens rotate to a predetermined rest angle by the action of the wearer's eyelid when placed on the wearer's eye. For example, the ballast can be a wedge and the rotation can be caused by the action of the eyelid on the wedge. Ballasting the contact lens to orient the contact lens is well known in the art. For example, toric contact lenses are ballasted to orient the lens so that the ortho-cylindrical correction provided by the lens is accurately aligned with the astigmatism of the wearer's eye. The contact lens of the present disclosure can provide a specific benefit to the wearer in a given orientation. For example, the contact lens can provide a specific benefit to the wearer when the maximum additional refractive power meridian is in a specific direction.

[0047] The contact lens can be substantially circular in shape and can have a diameter of about 4 mm to about 20 mm. The optical zone can be substantially circular in shape and can have a diameter of about 2 mm to about 10 mm. In some embodiments, the contact lens has a diameter of 13 mm to 15 mm and the optical zone has a diameter of up to 7 mm to 9 mm.

[0048] In the context of the present disclosure, the refractive power of the lens at any point in the optical zone can be defined as the radial curvature refractive power, the circumferential curvature refractive power, the average curvature refractive power (which is the average of the radial curvature refractive power and the circumferential curvature refractive power), the radial sagittal refractive power, the circumferential sagittal refractive power, and the average sagittal refractive power (which is the average of the radial sagittal refractive power and the circumferential sagittal refractive power).

[0049] The curvature refractive power and the sagittal refractive power are defined as follows.

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

[0051] The wavefront curvature, or the curvature refractive power Pc, is a function of the second derivative of the wavefront. The wavefront slope, or the slope-based refractive power Ps, is a function of the first derivative of the wavefront and varies with the slope (gradient) of the wavefront.

[0052] For a simple spherical lens, the curvature refractive power Pc is defined as follows. JPEG2023139348000001.jpg942 The slope-based refractive power Ps is defined as follows. JPEG2023139348000002.jpg936 That is, for a simple lens assuming paraxial (paraxial), Pc = Ps.

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

[0054] The radial sagittal refractive power is the sagittal refractive power in the 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 along the circumference of the lens.

[0055] A plurality of successive Curve each in Curve will be Curve will have a radial curvature (i.e., a curvature along its length) proportional to the radial curvature refractive power of the lens along the Curve The curvature of each Curve arc can be the curvature of the front surface of the lens or, alternatively, the curvature of the rear surface of the lens. The radial curvature refractive power of the lens along each Curve can result from a combination of the curvature of the rear surface of the lens and the curvature of the front surface of the lens.

[0056] In the case of a lens according to some embodiments of the present disclosure, the radial curvature refractive power monotonically increases along a meridian radially outward from the center of the lens. This increase in the radial curvature refractive power extending radially outward from the center of the lens can increase spherical aberration.

[0057] The increase in the radial curvature refractive power can be a continuous increase or can be an increase in a stepwise or non - continuous manner. Thus, a plurality of successive Curve along a given meridian can have an increasing radial curvature refractive power outward from the center of the lens, with Curve near the center of the lens having a (relatively) smaller radial curvature refractive power and Curve far from the center of the lens having a (relatively) larger radial curvature refractive power.

[0058] A plurality of successive Curve each in Curve can be inclined about the mid - point (mid - length point) along its length, and the Curve radial sagittal refractive power of the CurveThe radial curvature refractive power does not change. As a result of the local inclination of each of a series of consecutive multiple Curve in Curve , the focal point of light passing through a given Curve will deviate from the optical axis.

[0059] Each of a series of consecutive multiple Curve in Curve may have a constant radial curvature within the Curve . Therefore, the radial curvature refractive power along the length of each Curve may be constant.

[0060] Along any meridian, a center Curve may exist. The center Curve is centered on the optical axis and may have a constant radial curvature and a constant radial curvature refractive power. Alternatively, along any meridian, two central Curve portions may exist, and they extend in opposite directions radially outward from the optical axis. The radial curvature refractive power of the center Curve or the central Curve portion along any meridian may provide the base refractive power of the lens. The base refractive power may be between +0.5D and -15.0D, and preferably may be between approximately -0.25D and -15.0D.

[0061] Any one or all of a series of consecutive multiple Curve along a given meridian may have a constant radial curvature along the length of the Curve . As moving outward from the center of the lens, the radial curvature and the radial curvature refractive power of a series of consecutive multiple Curve increase. At the junction between each consecutive Curve , a stepwise increase in the radial curvature may exist. A transition region may exist between consecutive Curve . The transition region may result in a continuous or discontinuous increase in the radial curvature refractive power at each junction between consecutive Curve . Curve Curve ​​

[0062] Along the meridian, each Curve The radial curvature refractive power provided by can provide an additional refractive power. The additional refractive power can be between +0.5D and +20.0D, preferably between +0.5D and +10.0D. Curve The net refractive power along can be the sum of the base refractive power and the additional refractive power. Near the center of the lens Curve provides a smaller additional refractive power, and far from the center of the lens Curve can provide a larger additional refractive power.

[0063] A plurality of a series of Curve Each in Curve is the Curve Within, it can have a curvature that increases with the radial distance from the center of the lens.

[0064] Each Curve The radial curvature along the length of may not be constant and can increase with the radial distance from the center of the lens. Thus, for any given Curve The radial curvature refractive power along the length of increases with the increase in the radial distance from the center Curve This can result in a continuous increase in the radial curvature refractive power extending radially outward along any given meridian. The increase in the radial curvature refractive power extending outward from the optical axis can be a linear increase in the radial curvature refractive power. The central Curve centered on the optical axis, or two opposing central Curve extending radially outward from the optical axis along any given meridian can have a constant radial curvature, which can provide the base refractive power. The central Curve or the central Curve A series of a plurality of Curve Other in Curve can have a curvature that increases with the increase in the radial distance from the center of the lens. Thus, the central region of the lens (central Curve or central CurveThe portion that can span (can have a certain refractive power), and the remainder of the optical region can have an additional refractive power that increases as it extends radially outward from the central region.

[0065] Along the meridian, a series of continuous multiple Curve can be a series of symmetric multiple centered on the optical axis Curve and can have. A series of multiple along the meridian Curve can have at least 6 extending radially outward from the optical axis Curve and can have. A series of multiple along the meridian Curve can have at least 10 extending radially outward from the optical axis Curve and can have. A series of continuous multiple along the meridian Curve can have at least 3 extending radially outward on each side of the optical axis Curve and can have. A series of continuous multiple along the meridian Curve can have at least 5 extending radially outward on each side of the optical axis Curve and can have. Each in a series of continuous multiple Curve can have the same length. Alternatively, some in a series of multiple Curve Curve Curve can have different lengths.

[0066] All cross-sectional slices taken along all meridians of the optical zone can have a substantially identical curvature profile. Thus, the circumferential curvature refractive power of the central region of the lens that the center Curve spans, and optionally the circumferential sagittal refractive power, can be constant at a certain radial distance from the center of the lens. The center along each meridian Curve can have a constant radial curvature refractive power. The curvature refractive power of the entire central region can be that which the center along each meridian Curve can span and can be constant. Curve

[0067] ​Along each meridian, the radial curvature refractive power profile can be the same, in which case the circumferential curvature refractive power around the lens can be constant for a given radial distance from the center of the lens. Alternatively, along different meridians, the radial curvature refractive power profiles can be different when the number and length of a plurality of Curve vary and / or when the curvature of a plurality of Curve varies. In this case, the circumferential curvature refractive power profile around the optical zone can vary according to the meridian around the lens. The circumferential curvature refractive power around the optical zone can vary periodically or aperiodically. The circumferential curvature refractive power can oscillate between a maximum value and a minimum value. The circumferential curvature refractive power profile can oscillate in a profile such as a sine wave, a sawtooth, or a step.

[0068] Considering a 3D lens formed by summing 2D cross-sectional slices along each meridian, a plurality of Curve can be summed to form a series of concentric annular regions that spread outward from the central region. If each of the plurality of Curve in each series has a substantially identical radial curvature profile, their Curve can form circular concentric annular regions extending outward from the center of the lens. If the plurality of Curve along each meridian are of the same length, each concentric annular region can have the same width. A series of a plurality of Curve along each meridian can have different radial curvature refractive power profiles. This can result in concentric annular regions that spread partially around the periphery of the lens, or in oval or elliptical annular regions.

[0069] A cross-sectional slice taken along any meridian of the optical zone can have a substantially identical sagittal refractive power profile. Along a given meridian, each of a series of successive Curve can be tilted around the midpoint of its length, and the series of Curve can be CurveA radial sagittal refractive power profile along [the relevant direction] can occur. Along each meridian, the radial sagittal refractive power profile can be the same, in which case the circumferential sagittal refractive power around the lens is constant. Alternatively, along different meridians, the radial sagittal refractive power profile can be different when the [relevant elements] of each series are tilted by different amounts, or when the number and length of the [relevant elements] change. In this case, the circumferential sagittal refractive power profile around the optical zone can vary according to the meridian around the lens. The circumferential sagittal refractive power around the optical zone can vary periodically or aperiodically. The circumferential sagittal refractive power can oscillate between a maximum value and a minimum value. The circumferential sagittal refractive power profile can oscillate with a sine wave, sawtooth, or stepped profile. Curve when tilted by different amounts, or when the Curve number and length of the

[0070] The contact lens can include an elastomer material, a silicone elastomer material, a hydrogel material, a silicone hydrogel material, or a combination thereof. As understood in the field of contact lenses, a hydrogel is a material that retains water in an equilibrium state and does not contain a silicone-containing compound. A silicone hydrogel is a hydrogel that contains a silicone-containing compound. 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 about 30% to about 70% (wt / wt). In comparison, as described in the context of the present disclosure, the silicone elastomer material has a water content of about 0% to less than 10% (wt / wt). Typically, the silicone elastomer material used in the present method or apparatus has a water content of 0.1% to 3% (wt / wt).Examples of suitable lens formulations (compositions) include those having 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, 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, etc.

[0071] Alternatively, the lens may comprise, consist essentially of, or consist of a silicone elastomer material. For example, the lens may comprise, consist essentially of, or consist of a silicone elastomer material having a Shore A hardness of 3 to 50. The Shore A hardness can be determined using conventional methods (e.g., using method DIN 53505) as understood by those skilled in the art. Other silicone elastomer materials can be obtained from, for example, NuSil Technology, or the Dow Chemical Company.

[0072] According to a second aspect, the present disclosure provides a method of manufacturing a contact lens. The method may comprise a step of forming a contact lens, the contact lens including an optical zone centered on an optical axis and a peripheral zone surrounding the optical zone. A cross-sectional slice of the optical zone taken along a meridian includes a plurality of continuous Curve that extend radially outward from the optical axis. A plurality of light rays from a distant point source passing through the midpoint of each Curve converge toward a single point on the first optical axis. For each Curve , a plurality of light rays from a distant point source passing through the Curve converge toward a point at a first distance from the optical axis.

[0073] The lens may include any of the features described above with respect to the first aspect of the present disclosure.

[0074] The manufacturing method may include a step of forming a female member having a concave lens-forming surface and a male member having a convex lens-forming surface. The method may include a step of filling a gap between the female member and the male member with a bulk lens material. The method may further include a step of curing the bulk lens material to form a lens.

[0075] The contact lens may be formed using lathe work. The lens may be formed by a casting process, a spin casting process, a lathe work process, or a combination thereof. As understood by those skilled in the art, casting refers to a process of forming a lens by placing a lens-forming material between a female forming member having a concave lens member-forming surface and a male forming member having a convex lens member-forming surface.

[0076] In a third aspect, the present disclosure provides a method of designing a contact lens. The method comprises modeling a contact lens. The lens includes an optical zone centered on the optical axis and a peripheral zone surrounding the optical zone. A cross-sectional slice of the optical zone taken along a meridian has a radial curvature refractive power profile that increases with the radial distance from the optical axis. The method further comprises, within the model, centering the cross-sectional slice of the optical zone on a central Curve starting with and spreading radially outward to a series of a plurality of continuous Curve dividing into. The method further comprises, within the model, each of the series of a plurality of continuous Curve in Curve tilting about the midpoint of the Curve such that a plurality of light rays from a distant point source passing through the midpoint of each Curve converge toward a single point on the optical axis, while for each Curve a plurality of light rays passing through the Curve of that converge toward a point at a first distance from the optical axis. The method further comprises designing a lens based on the modeled lens.

[0077] The lens can be designed using modeling, which can be computer-implemented modeling. The lens to be designed can include any of the foregoing features.

[0078] Figure 1A shows a schematic plan view of a contact lens using a treatment zone that provides a myopic defocus image to reduce the progression of myopia. Figure 1B is a schematic side view of the contact lens of Figure 1A. The lens 1 includes an optical zone 2 that generally covers the pupil and a peripheral zone 4 located above the iris. The peripheral zone 4 provides mechanical functions including increasing the size of the lens to make the lens 1 easier to handle, providing a ballast to prevent rotation of the lens 1, and providing a shaped area to improve the comfort of the wearer of the lens 1. The optical zone 2 provides the optical function of the lens 1, and the optical zone 2 includes an annular region 3 and a central region 5. The lens 1 has a refractive power with a curvature in the radial direction of the base, which is equal to the sagittal refractive power in the radial direction of the base. The refractive power of the base results from the radius of curvature of the surface of the lens 1. The center of curvature of the central region 5 is on the first optical axis 19 (shown in Figure 2A). The annular region 3 has a refractive power with a curvature in the radial direction that is greater than the refractive power with a curvature in the radial direction of the base. The refractive power with a curvature in the radial direction of the annular region 3 is provided by the radius of curvature 6 of the annular region 3, and the radius of curvature 6 is smaller than the radius of curvature 7 of the central region 5 as shown in Figure 3. The center of curvature of the annular region 3 is on the first optical axis 19. The annular region 3 has a greater refractive power than the central region 5. As shown in Figure 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 is on the proximal focal plane 13, and the focal point of the central region 5 is on the distal focal plane 17, and the distal focal plane 17 is further away from the back surface of the lens. As shown in Figure 2C, in the case of a point source at infinity, the light rays focused by the central region 5 form a focal image (a focused image) 23 on the distal focal plane 17. The light rays focused by the central region 5 also generate an unfocused (unfocused) blur spot 27 on the proximal focal plane 13.

[0079] As shown in FIG. 2B, the light rays focused by the annular region 3 form a focal image 21 on the proximal focal plane 13. The light rays focused by the annular region 3 diverge after the proximal focal plane 13, and the diverging light rays generate an unfocused (not focused) annular image 25 on the distal focal plane 17. As described above, the unfocused annular image 25 can result in the wearer of the lens 1 seeing a "halo" around the focused distant image.

[0080] FIG. 4A is a plot (graph) 31 showing the change in the radial sagittal refractive power of the lens 1 shown in FIGS. 1A and 1B, and FIG. 4B is a plot (graph) 33 showing the change in the radial curvature refractive power of the lens 1 shown in FIGS. 1A and 1B. FIGS. 4A and 4B show the change in refractive power along the radial diameter of the lens 1. In the case of this lens 1, since the annular region 3 has a greater refractive power than the central region 5 and since the annular region 3 has an on-axis center of curvature, the radial sagittal refractive power (shown by the curve 35) is greater across the annular region 3 than across the central region 5. The radial curvature refractive power (shown by the curve 37) is also greater across the annular region 3 than across the central region 5.

[0081] FIG. 5A shows a schematic plan view of a contact lens 101 having an aspheric optical system for reducing the progression of myopia. This lens 101 has been processed for an off-axis curvature center and does not form an on-axis image in the proximal focal plane. FIG. 5B shows a schematic side view of the lens of FIG. 5A. Similar to the lens 1 of FIGS. 1A and 1B, the lens 101 includes an optical zone 102 that generally covers the pupil and a peripheral zone 104 that is located above the iris. The lens 101 includes an optical zone 102 that generally covers the pupil and a peripheral zone 104 that is located above the iris. The peripheral zone 104 provides mechanical functions including increasing the size of the lens to make the lens 101 easier to handle, providing a ballast to prevent rotation of the lens 101, and providing a shaped area that improves the comfort of the wearer of the lens 101. The optical zone 102 provides the optical function of the lens 101, and the optical zone 102 includes an annular region 103 and a central region 105. The lens 101 has a curvature refractive power in the radial direction of the base, which is equal to the sagittal refractive power in the radial direction of the base. The refractive power of the base results from the radius of curvature of the surface of the lens 101. The center of curvature of the central region 105 is on the first optical axis 119 (shown in FIG. 6A). The annular region 103 has a radial curvature refractive power that is greater than the radial curvature refractive power of the base. The radial curvature refractive power of the annular region 103 is provided by the radius of curvature of the annular region 103, which is smaller than the radius of curvature of the central region 105. However, in contrast to the lens 1 of FIG. 1A, in the case of the lens 101 shown in FIGS. 5A and 5B, the curvature of the annular region 103 cannot be defined by a single spherical surface, and the center of curvature of the annular region 103 is not on the first optical axis 119. This is shown in FIG. 6D. The annular region 103 is inclined with respect to the central region 105, and the outer edge of the annular region 103 is higher (see FIG. 5B) with respect to its inner edge than in the case of the lens 1 of FIGS. 1A and 1B. This changes the radial sagittal refractive power of the annular region 103 but does not change the radial curvature refractive power of the annular region 103. As shown in FIG. 6D, the front surface of the central region 105 defines a part of the surface of a sphere 107 with a larger radius. The front surface of the annular region 103 defines a curved annular surface 106 with a smaller radius.

[0082] At the distal focal plane 117, the light rays passing through the central region 105 are focused. The annular region 103 acts as an optical beam stop, which results in a small spot size 124 of light at the distal focal plane 117, as shown in FIG. 6C.

[0083] No single image is formed on the proximal focal plane 113. As shown in FIG. 6B, at the proximal focal plane 113, for an infinitely distant point source, the light rays passing through the central region 105 generate a blur circle 128, similar to the lenses of FIGS. 1A - 2B. On the other hand, the light rays from a distant point source passing through the annular region 103 generate a focused ring 122 that surrounds the blur circle 128, as shown in FIG. 6B. FIG. 6B shows the light pattern generated for a distant point source. In contrast to the lens 1 of FIGS. 1A and 1B, the lens 101 of FIGS. 5A and 5B does not generate a single image or an on - axis image at the proximal focal plane 113, which could be used to avoid the need for the eye to accommodate to a nearby object. For a distant extended object, the focal image formed at the proximal focal plane 113 is a convolution of (i) the focal image of the extended object that would be obtained with a conventional lens having the refractive power of the annular region 103 and (ii) the optical transfer function representing the optical effect of the annular region 103.

[0084] In contrast to the lens of FIGS. 1A and 1B, an annular or "halo" effect does not occur at the distal focal plane 117.

[0085] FIG. 7A is a plot (graph) 131 showing the change in the radial sagittal refractive power of the lens 101 shown in FIGS. 5A and 5B. FIG. 7B is a plot (graph) 133 showing the change in the radial curvature refractive power of the lens 101 shown in FIGS. 5A and 5B. FIGS. 7A and 7B show the refractive power change along the radial diameter of the lens 101. In the case of this lens 101, since the annular region 103 has a greater refractive power than the central region 105, this means that the radial curvature refractive power (shown by curve 137) is greater across the annular region 103 than across the central region 105. However, the annular region 103 is inclined with respect to the central region 105, and the annular region 103 has an off-axis curvature center. The inclination of the annular region 103 with respect to the central region 105 means that, as shown by curve 135, at the boundary between the central region 105 and the annular region 103, the radial sagittal refractive power is even more negative than the radial sagittal refractive power of the central region 105. The radial sagittal refractive power can increase in response to an increase in the radial distance toward the outer edge of the annular region 103.

[0086] FIG. 8A is a schematic plan view of a contact lens 201 according to an embodiment of the present disclosure. Similar to the lens 1 of FIGS. 1A and 1B and the lens 101 of FIGS. 5A and 5B, the lens 201 includes an optical zone 202 that generally covers the pupil and a peripheral zone 204 that is located above the iris. The peripheral zone 204 provides mechanical functions including increasing the size of the lens 201 to make the lens 201 easier to handle, providing a ballast to prevent rotation of the lens 201, and providing a shaped area that improves the comfort of the wearer of the lens 201. The optical zone 202 provides the optical function of the lens 201. The optical zone 202 includes a central region 205 and a series of concentric annular regions 203', 203", 203"', 203"".

[0087] FIG. 8B shows a cross-sectional slice taken along line A-A of the optical zone 202 of the lens 201 shown in FIG. 8A. In 2D (two-dimensional), the cross-sectional slice of the optical zone 202 straddles the central Curveshows 205a. Central Curve 205a has a radial curvature profile that provides a radial curvature refractive power. The curvature is central Curve constant along the length of 205a. A series of continuous multiple Curve 203a - 203h extend symmetrically radially outward from the central region 205. Each Curve 203a - 203h has a constant radial curvature profile along its length, but the continuous multiple Curve of the radial curvatures are increasing outward from the center Curve 205a, so the innermost Curve 203a, 203e have a larger radius of curvature and thus a smaller radial curvature refractive power than the outermost Curve 203h, 203d. Therefore, the radial curvature refractive power of the optical zone 202 increases outward from the central region 205 of the lens 201. The radial curvature refractive power profile shows a step - like increase at the junctions between each Curve 203a - 203h.

[0088] Each Curve 203a - 203h is tilted about the mid - point of its length, Curve and point X is marked at that point for 203a. Tiling each Curve 230a - 203h about its mid - point reduces the radial sagittal refractive power along the length of 203a - 203h, but Curve does not change the radial curvature refractive power along the length of 203a - 203h. Curve

[0089] In the case of the lens shown in Figure 8A, a cross - sectional slice taken along any meridian generates the same curvature profile. Therefore, considering the optical region 202 in 3D (three - dimensional), the optical region 202 consists of a central region 205 spanned by the central Curve 205a and a series of continuous multiple CurveIt is composed of a series of concentric annular regions 203’, 203”, 203”’, 203”” formed from 203a to 203h. In the case of the lens shown in FIGS. 8A and 8B, each Curve 230a to 203h has the same length. The concentric annular regions 203’, 203”, 203”’, 203”” are circular and have substantially the same radial width.

[0090] FIG. 9 shows a partial ray diagram of the lens 201 of FIGS. 8A and 8B. A plurality of rays passing through the central region 205 (represented by the central Curve 205a) from a distant point source converge towards a spot 215 on the optical axis 219 of the distal focal plane 217. A plurality of rays (dashed-dotted lines) passing through the midpoints of each Curve 203a to 203h from a distant point source also converge towards the same spot 215 on the optical axis 219 of the distal focal plane 217. In the case of a given Curve 203e, a plurality of rays (broken lines) passing through the Curve from a distant point source converge towards a point 216 at a first distance (indicated by the symbol Y) from the optical axis 219 on a focal plane in front of the distal focal plane 217 (i.e., on the side closer to the lens).

[0091] FIG. 10 shows a method 501 for designing a contact lens, and the lens is a lens according to an embodiment of the present disclosure. In a first step 503, the method includes modeling a contact lens. The lens includes an optical zone centered on the optical axis and a peripheral zone surrounding the optical zone. The cross-sectional slice of the optical zone taken along the meridian has a radial curvature refractive power profile that increases with the radial distance from the optical axis. In a second step 505, the method includes dividing, within the model, the cross-sectional slice of the optical zone into a series of continuous Curve extending radially outward from a center centered on the optical axis. Curve In a third step 507, the method includes, within the model, each Curve in a series of continuous Curve being the CurveA step of tilting around the midpoint, wherein a plurality of light rays from a distant point light source passing through the midpoint of each Curve converge toward a point on the optical axis, and for each Curve a plurality of light rays passing through the Curve converge toward a point at a first distance from the optical axis. The method comprises the steps of:

[0092] Figures 11A through 11C show an example of a lens 601 modeled using the method 501 described in Figure 10. In a first step 503, the lens 601 shown in Figure 11A is modeled. The lens 601 includes an optical zone 602 centered on the optical axis 619 and a peripheral zone 604 surrounding the optical zone 602. The optical zone 602 has a central region 605 centered on the optical axis. Light from a distant point light source passing through the central region 605 converges toward a point 615 on the optical axis of the distal focal plane 617. Figure 11B shows a cross-sectional slice of the optical zone 602 taken along the meridian, and the dashed curve 701 shows the radial curvature profile of the lens 601 modeled in the first step 503. The center Curve 705a spans the central region 605 of the lens. The radial curvature refractive power profile of the lens 601 increases with the radial distance from the optical axis 619. In a second step 505, within the model, a cross-sectional slice of the lens 601 is divided into a plurality of successive Curve and in a third step 507, within the model, each Curve in the plurality of successive Curve is tilted around the midpoint of the Curve . Thereby, the red curve 801 shown in Figure 11B is generated. This curve includes an unchanged central Curve 705a from the center of the lens modeled in the first step and a plurality of successive tilted Curve 805a to 805h. Curve Including 805a to 805h. Curve Even if 805a to 805h are tilted, the radial curvature refractive power of the Curve 805a to 805h does not change. Therefore, each CurveA plurality of light rays (indicated by the dashed-dotted line) from a distant point light source passing through the midpoints of 805a to 805h converge toward a point on the optical axis 619 of the distal focal plane 617. Curve When 805a to 805h are tilted, the Curve radial sagittal refractive power of 805a to 805h decreases, so for each Curve of 805a to 805h, the Curve plurality of light rays (indicated by the dotted line) passing through it converge toward a point 816 at a first distance (indicated by the symbol H) from the optical axis 619. FIG. 11C shows a schematic plan view of a lens 901 designed based on the dotted curve 801. The lens 901 has an optical zone 902 that substantially covers the pupil and a peripheral zone 904 that sits above the iris. The optical zone 902 provides the optical function of the lens 901. The optical zone 902 has a central region 905 and a series of concentric annular regions 903’, 903”, 903”’, 903”” having the radial curvature of the curve 801 shown in FIG. 11B.

[0093] Those skilled in the art will understand that the features of these exemplary embodiments can be combined in other embodiments within the scope of the present disclosure.

[0094] In the foregoing description, integers or elements having known obvious or predictable equivalents have been mentioned, but such equivalents are incorporated herein as if individually described herein. To determine the true scope of the present disclosure, reference should be made to the claims. The claims should be construed to include any such equivalents. It will also be understood by the reader that the integers or features of the present disclosure described as being advantageous or convenient or the like are optional and do not limit the scope of the independent claims. Furthermore, such optional integers or features may be beneficial in some embodiments of the present disclosure, but may not be desirable in other embodiments and thus may not exist in other embodiments.

Claims

**Claim 1** A contact lens, comprising: an optical zone centered on the optical axis; and a peripheral zone surrounding the optical zone; wherein a cross-sectional slice of the optical zone taken along a meridian includes a series of continuous curves having a radially increasing curvature refractive power profile with respect to the radial distance from the optical axis, a plurality of light rays from a distant point source passing through the midpoint of each curve converge towards a single point on the first optical axis, and for each curve, a plurality of light rays from a distant point source passing through the curve converge towards a single point at a first distance from the optical axis. A contact lens characterized by the above. **Claim 2** Each curve in the series of continuous curves has a constant curvature within the curve. The contact lens according to claim 1, characterized by the above. **Claim 3** Each curve in the series of continuous curves has a curvature that increases with the radial distance from the center of the lens within the curve. The contact lens according to claim 1 or 2, characterized by the above. **Claim 4** The series of continuous curves is a series of symmetric curves centered on the optical axis. The contact lens according to any one of claims 1 to 3, characterized by the above. **Claim 5** The series of continuous curves includes at least six curves. The contact lens according to any one of claims 1 to 4, characterized by the above. **Claim 6** A cross-sectional slice taken along any meridian of the optical zone has a substantially identical radial curvature profile. The contact lens according to any one of claims 1 to 5, characterized by the above. **Claim 7** A cross-sectional slice taken along any meridian of the optical zone has a substantially identical radial sagittal refractive power profile. The contact lens according to any one of claims 1 to 6, characterized by the above. **Claim 8** The circumferential curvature refractive power profile of the optical zone varies with the meridian around the lens. The contact lens according to any one of claims 1 to 5, characterized by the above. **Claim 9** The sagittal refractive power profile of the optical zone varies with the meridian around the lens. The contact lens according to any one of claims 1 to 5, characterized by the above. **Claim 10** At the center of the optical zone, the lens has a base refractive power between -0.25 D and -15.0 D The contact lens according to any one of claims 1 to 9, characterized in that

11. The series of continuous curves have a curvature that provides an additional refractive power between +0.5 D and +20.0 D The contact lens according to any one of claims 1 to 10, characterized in that

12. The optical zone has a curvature refractive power resulting from the curvature of the front and / or rear surface of the lens The contact lens according to any one of claims 1 to 11, characterized in that

13. The lens includes an elastomer material, a silicone elastomer material, a hydrogel material, or a silicone hydrogel material, or a mixture thereof The contact lens according to any one of claims 1 to 12, characterized in that

14. A method for manufacturing a contact lens, comprising The step of forming the contact lens according to any one of claims 1 to 13 A method characterized by comprising

15. A method for designing a contact lens, comprising The step of modeling the contact lens Comprising The lens An optical zone centered on the optical axis, and A peripheral zone surrounding the optical zone Including The cross-sectional slice of the optical zone taken along the meridian has a radial curvature refractive power profile that monotonically increases with the radial distance from the optical axis, and The method further comprises In the model, dividing the cross-sectional slice of the optical zone into a series of continuous curves that spread radially outward starting from a central curve centered on the optical axis, and In the model, tilting each curve in the series of continuous curves around the midpoint of the curve so that a plurality of light rays from a distant point light source passing through the midpoint of each curve converge to a point on the optical axis, while a plurality of light rays passing through the curve for each curve converge to a point at a first distance from the optical axis, and The step of designing a lens based on the modeled lens A method characterized by comprising

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