Multifocal ophthalmic lenses and related methods

Abstract

Provided are a multifocal ophthalmic lens that provides a more stable ratio of near vision accommodation to distance vision accommodation in the presence of changes in the wearer's pupil size, a method for manufacturing the multifocal ophthalmic lens, and a method for improving an individual's visual acuity. A multifocal ophthalmic lens has a surface that varies over at least a portion of the lens to form a surface power map. The surface power map comprises a spiral having power that varies substantially periodically both radially outward from and angularly about the optical axis of the lens. The period of the radial variation is greater than 100 microns, and the period of the angular variation is greater than 6 degrees. Methods of making and using the multifocal ophthalmic lens are also described.

Description

[Technical field]

[0001] The present invention relates to multifocal ophthalmic lenses. More specifically, but not exclusively, the present invention relates to multifocal ophthalmic lenses having a helical surface power map, as well as methods of making and using such lenses. [Background technology]

[0002] In the context of the present disclosure, a multifocal ophthalmic lens is an ophthalmic lens that provides simultaneous focusing at more than one distance. This is typically accomplished by subdividing the ophthalmic lens into a plurality of regions. A first subset of the plurality of regions is provided with a first lens power (e.g., distance vision) corresponding to a first focusing distance. A second subset of the plurality of regions is provided with a second lens power (e.g., near vision) corresponding to a second focusing distance.

[0003] In a multifocal contact lens, the regions can be formed as concentric circles around the optical axis of the contact lens, which alternate between a first lens power and a second lens power. That is, in this example, the power map or power profile of the optical zone of a typical multifocal contact lens comprises at least two alternating concentric circles of a first lens power and a second lens power. However, such contact lenses can cause difficulties for the wearer in variable light conditions. In lower light conditions, the pupil of the wearer's eye expands to provide a larger opening for the incoming light, increasing the amount of light admitted into the eye, thereby providing improved low light vision. When conditions become brighter, the pupil contracts to provide a smaller opening, thereby limiting the amount of light admitted into the eye. As the wearer's pupil expands and contracts, the number of concentric rings on the contact lens positioned across the wearer's entrance pupil will also change. As the pupil expands, a greater number of concentric rings will be positioned across the wearer's entrance pupil. Similarly, as the pupil constricts, fewer concentric rings will be positioned across the wearer's entrance pupil. As the concentric rings alternate between the first and second lens powers, the ratio of the first lens power to the second lens power positioned across the wearer's entrance pupil will change as the wearer's pupil constricts and dilates. As the pupil constricts, only one of the amounts of near and far accommodation will be reduced until the pupil constricts to the next smallest concentric diameter. At this point, only the other amount of near and far accommodation will be reduced until the pupil constricts again to the next smallest concentric diameter. This cycle is repeated as the pupil constricts, causing a variation in the ratio of near accommodation to far accommodation as the pupil constricts. It will be appreciated that the same effect occurs in reverse as the pupil dilates. These variations in the ratio of near to far accommodation can cause dismay and even loss of multifocal vision for the wearer. Generally, the more the wearer's pupils are constricted, the worse this variation in ratio becomes.Thus, in bright conditions, especially when the pupil is constricted close to its minimum size, the wearer of such a multifocal contact lens may find that the ability of the multifocal contact lens to provide high acuity in both near and far vision is hindered. This effect is even worse for two-zone multifocal contact lenses, which are one of the more mainstream designs of multifocal contact lenses. Two-zone multifocal contact lenses comprise an inner circle of a first lens power and a single surrounding peripheral ring of a second lens power. That is, the more the pupil of the wearer of such contact lenses constricts, the less of the second lens power is positioned over the wearer's entrance pupil. In some cases, the pupil may further constrict to the extent that none of the second lens power is positioned over the wearer's entrance pupil, causing a complete loss of multifocal vision. Other multifocal contact lenses utilize a similar principle, but instead of alternating concentric rings, they include an aspheric power profile that provides a more gradual transition from near to far vision power compared to lenses that incorporate alternating concentric rings. Such lenses also undergo variation in the ratio of lens power positioned across the wearer's entrance pupil as the wearer's pupil dilates and constricts. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention seeks to alleviate the above mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved multifocal ophthalmic lens. [Means for solving the problem]

[0005] The present invention provides, according to a first aspect, a multifocal ophthalmic lens, the surface of the ophthalmic lens varying over at least a portion of the lens to form a surface power map, the surface power map comprising a spiral having a substantially periodic variation in both a radial direction outward from the optical axis of the lens and an angular direction thereabout, the period of the radial variation being greater than 100 microns and the period of the angular variation being greater than 6 degrees.

[0006] A contact lens having a surface power map with a spiral can provide a more stable ratio of near to distance accommodation in the presence of changes in the wearer's pupil size. As light conditions change, the wearer's pupil will dilate and constrict to adjust the amount of light admitted into the eye. When conditions become brighter, the pupil will constrict to reduce the amount of light allowed into the eye. When conditions become darker, the pupil will dilate to allow more light into the eye. Prior art multifocal contact lenses may use alternating concentric rings of near and distance accommodation, e.g., a central circle of distance accommodation surrounded by a peripheral circle of near accommodation, or existing multifocal contact lenses may use aspheric power profiles to provide multifocal vision. As discussed above, these contact lenses are subject to variations in the ratio of near to distance accommodation provided across the wearer's entrance pupil as the wearer's pupil dilates and constricts. These variations can cause dismay and even loss of multifocal vision for the wearer.

[0007] The helical power map has a constant ratio of near to distance accommodation over the entire diameter range that includes the helical map. That is, a contact lens with a helical power map can maintain either a substantially constant ratio of near to distance accommodation (if the helix encompasses the entire optical zone of the lens) or a monotonically changing ratio (if the helix encompasses only a radial subportion of the optical zone of the lens) as the pupil contracts or dilates. That is, a contact lens with a helical power map provides improved multiple accommodation in the presence of variable lighting conditions.

[0008] It will be appreciated by those skilled in the art that if the power map varies smoothly (e.g. sinusoidally), the power map will comprise other lens powers than just a first lens power corresponding to near vision and a second lens power corresponding to far vision. In such a case, the power map will also comprise areas with lens powers between the first and second powers. It will be appreciated that this does not affect or impair the above-mentioned advantage of providing a consistent and stable variation of the add power positioned across the wearer's entrance pupil. It will be appreciated by those skilled in the art that this advantage derives from the fact that, for a helical power map, the configuration of the add power at a particular radius does not vary according to the radial distance from the optical axis of the lens.

[0009] According to a second aspect of the present invention, there is also provided a method of manufacturing a multifocal ophthalmic lens. The method comprises the step of operating a lathe to shape at least one surface of a lens, a mold for a lens, or an insert for manufacturing a mold for a lens. At least a portion of the surface is shaped such that it forms a power map that comprises a spiral. The power map varies substantially periodically both radially outward from the optical axis of the lens and angularly thereabout. The period of the radial variation is greater than 100 microns and the period of each of the angular variations is greater than 6 degrees.

[0010] According to a third aspect of the present invention, there is also provided a method of using a multifocal ophthalmic lens as described herein. The method may be effective in improving the visual acuity of a presbyopic lens wearer (e.g., an individual aged 40 or older). Alternatively, the method may be effective in attenuating the progression of refractive errors, such as attenuating the progression of myopia or hyperopia. When the lens of the present invention is used to attenuate the progression of myopia, the method includes providing the ophthalmic lens to an individual having an eye capable of accommodation. Some embodiments of the method include providing the ophthalmic lens to an individual who is between about 5 and about 18 years old. The providing step may be performed by an ophthalmic practitioner, such as an optometrist or an optometrist. Alternatively, the providing step may be performed by a lens distributor who prepares the ophthalmic lens for delivery to the lens wearer.

[0011] It will of course be appreciated that features described in relation to one aspect of the invention may be incorporated in other aspects of the invention, for example a method of the invention may incorporate any of the features described in relation to an apparatus of the invention, and vice versa.

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

[0013] [Figure 1] FIG. 1 illustrates a contact lens according to an embodiment of the present invention. [Diagram 2] FIG. 2 shows a power map of a first surface of a portion of a contact lens according to a first embodiment of the present invention. [Diagram 3] FIG. 2 shows a power map of a second surface of a portion of a contact lens according to a second embodiment of the present invention. [Figure 4] FIG. 2 shows a lens power map of the aforementioned portion of the contact lens of the second embodiment. [Diagram 5] FIG. 13 shows a lens power map of a portion of a contact lens according to a third embodiment. [Figure 6] 10 is a flow diagram illustrating steps of a method according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention provides a multifocal ophthalmic lens according to a first aspect. The surface of the ophthalmic lens varies over at least a portion of the lens to form a surface power map. It will be appreciated by those skilled in the art that the variation in surface comprises a variation in the curvature of the lens surface. The surface power map comprises a spiral having a substantially periodic variation in power both radially outward from and angularly about the optical axis of the lens. The period of the radial variation is greater than 100 microns and the period of the angular variation is greater than 6 degrees.

[0015] The ophthalmic lens may be a contact lens. The first surface may vary across an optical zone of the contact lens to form a first surface power map. Thus, the above-mentioned portion of the lens may correspond to an optical zone of the lens. Alternatively, the ophthalmic lens may be an intraocular lens or a spectacle lens.

[0016] It will be appreciated that in the case of contact lenses, the lens will comprise an optical zone that provides vision correction. Contact lenses according to embodiments of the present invention may further comprise a surrounding peripheral zone that does not provide any additional focusing or vision correction. In such embodiments, the peripheral zone may only serve to help maintain the contact lens in a fixed position on the wearer's eye. It will be appreciated by those skilled in the art that the surface power map is therefore defined by the variation of the first surface across the optical zone of the lens. Variations of the lens surface outside the optical zone (e.g., within the peripheral zone) are not treated as defining the surface power map in the context of the present invention. Similar considerations apply to intraocular lenses, which may further comprise an optical zone and an (optional) peripheral zone.

[0017] The optic zone of a contact lens according to embodiments of the present invention may have a diameter between 4 mm and 9 mm depending on the type of contact lens. For example, the diameter of the optic zone may be about 5 mm, about 6 mm, about 7 mm, or about 8 mm. In some embodiments, the diameter of the optic zone of the contact lens is between 7 mm and 9 mm. The optic zone has an optical axis corresponding to its geometric center.

[0018] In the case of a spectacle lens, the entire lens may function to provide vision correction, not just a portion of the lens, i.e., the ophthalmic lens may be a spectacle lens. The first surface may vary across the lens to form a first surface power map.

[0019] One or both of the radial and angular variations may be of constant magnitude across the portion.

[0020] The period of the radial variation may be greater than 200 microns, preferably greater than 400 microns, and more preferably greater than 800 microns. The period of the angular variation may be greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and even more preferably greater than 36 degrees.

[0021] The power may vary smoothly over the aforementioned portion. The power may vary continuously without any discontinuities. The power may vary at a rate of variation of less than 80 D / mm, preferably less than 40 D / mm, more preferably less than 20 D / mm over the aforementioned portion. The surface may vary smoothly over the aforementioned portion. The surface may vary continuously without any discontinuities. A smoothly varying power may result in a lens surface profile that is easier to manufacture using a lathe. It will be appreciated by those skilled in the art that manufacturing an ophthalmic lens using a lathe may include using a lathe to mold one or more surfaces of a lens (e.g., a contact lens), a mold for a lens (e.g., a mold for a contact lens), and an insert for a lens mold (e.g., an insert for a contact lens mold). Sharp transitions and features may be difficult to achieve using a lathe. Thus, lenses with such features having a desired or required definition often cannot be reproduced when manufactured using a lathe. It will therefore be appreciated that the term smooth in this context also means sufficiently smooth to permit the desired shaping of a surface of a lens, a mold for a lens, or an insert for a lens mold using a lathe.

[0022] The power may vary as a square wave in one or both of the radial and angular directions. The power may vary as a round square wave in one or both of the radial and angular directions. The power may vary as a sine wave in one or both of the radial and angular directions.

[0023] Each power variation in the radial and angular directions may be associated with a respective waveform. Furthermore, the power maps of these waveforms may be symmetric with a substantially equal balance between near and distance vision corrections. Alternatively, the power maps may be biased toward either distance or near vision corrections. That is, the power maps of these waveforms may be asymmetric in one or both of the radial and angular directions.

[0024] The period of one or both of the radial and angular variations may be substantially constant over the aforementioned portions of the lens.Embodiments of the invention in which the radial and angular variations are substantially constant result in lens surface profiles that are easier to manufacture using a lathe compared to embodiments in which the radial and angular variations are not constant.In contact lenses according to embodiments of the invention, one or both of the radial and angular variations may be substantially constant from the peripheral zone of the optical zone to the optical axis of the optical zone.

[0025] The period of either or both of the radial and angular variation may vary with either or both of the radial distance from and angular position about the optical axis of the lens. Embodiments of the invention in which the period of either or both of the radial and angular variation varies with position on the lens can provide lenses in which the properties of the helix (e.g., the twist rate or arm width of the helix) are different in different regions of the lens.

[0026] The changes in period of radial variation can be separated by a blended region of linearly varying lens power, for example. The blended region can thus comprise concentric rings of linearly varying lens power between a first region having a first period of radial variation and a second region having a second period of radial variation. The blended region can thus provide a smooth transition between regions of radial variation of different periods. The regions of radial variation of different periods may be separated by two blended regions and an intervening region of substantially constant lens power. The blended region can have a width (in plan view) of about 25 micrometers to about 200 micrometers.

[0027] The period of the angular variation may be less than 180 degrees, preferably less than 90 degrees, more preferably less than 45 degrees. The helix may comprise more than two arms, preferably more than four arms, more preferably more than eight arms. It will be appreciated by those skilled in the art that the period of the sinusoidal variation of the angle determines the number of arms on the helix.

[0028] The period of the radial variation may be between 24 mm and 2 mm. The period of the radial variation may be between 16 mm and 4 mm. Each arm of the spiral may twist through between a quarter turn and 40 turns. It will be appreciated by those skilled in the art that the number of turns through which an arm of the spiral twists is determined by the period of the radial variation and the radius (or size) of the aforementioned portion of the lens. It will be appreciated that references to the radius of this portion (i.e. the optical zone of the contact lens) refer to a distance of half the diameter of a plan view of this portion. In this context, the plan view is intended to be taken as a view along the optical axis of the lens.

[0029] The ratio of the period of radial variation to the period of angular variation may be greater than 0.1 mm:6°. Each arm of the spiral may be greater than 0.1 mm, preferably greater than 0.5 mm, more preferably greater than 1 mm. The width of the spiral arm is determined as the power map viewed in plan view (i.e. along the optical axis of the lens) as shown in the attached drawings. It will be appreciated by those skilled in the art that the width of an arm at a given radius is defined as the vertical width of the arm (i.e. the width in a direction perpendicular to the given radius). The width of an arm is in this context defined as the distance between two points immediately adjacent to each side of the arm, both of which have either a maximum or minimum gradient and which bracket a power undergoing a single positive or negative deviation. It will be appreciated by those skilled in the art that such a definition of width gives a linear measurement of the arm width along a tangential to a circle of a given radius. It will further be appreciated by those skilled in the art that a measurement of the width under this definition will be different from a measurement of the arm width taken as an arc of a circle with a given radius. Unlike width measurements under the linear width definition, such arc-based measurements are considered to be proportional to the angular period. The magnitude of the difference between the widths obtained by these two methods will depend on the angular period in the particular case at hand.

[0030] Each arm of the spiral may extend from the center of the portion of the lens to the periphery of the portion. An embodiment of the invention in which the arms of the spiral extend from the center of the portion of the contact lens to the periphery of the portion can provide a substantially constant ratio of the first lens power to the second lens power in the presence of varying pupil dilation. Such an embodiment thereby provides high acuity multifocal vision under a wide range of light conditions.

[0031] The above-mentioned portions of the lens may include a central region and an outer region. The central region may immediately surround the optical axis of the lens. The outer region may immediately surround the central region. The power of the central region may not vary periodically across the central region. The outer region may include angular and radial variations in power. Providing a contact lens having an optical zone with a central region having a lens power corresponding to distance vision and lacking periodic power variations can ensure that the wearer maintains high acuity distance vision even under bright conditions. For example, this may be particularly advantageous for the wearer when driving.

[0032] Contact lenses according to embodiments of the present invention may include a surrounding peripheral zone that does not provide any additional focusing or vision correction and serves only to help maintain the contact lens in place on the wearer's eye. In a conventional manner, when worn on the eye, the contact lens rests on the cornea and the optical zone substantially encompasses the wearer's pupil. Thus, the diameter of the central zone may be less than 50% of the diameter of the optical zone, preferably less than 40%, and more preferably less than 30%. The central zone may be smaller than the minimum pupil size of the wearer of the contact lens. Such embodiments of the present invention may provide a central zone that is smaller than the minimum pupil size of the wearer. An embodiment of the present invention having a central zone that is smaller than the minimum pupil size of the wearer may maintain high acuity near and distance vision in the presence of changing light conditions.

[0033] The power of the central region can be substantially constant (e.g., the power can vary by less than 0.25 diopters (D) from the reference power of the central region). The central region can have a lens power corresponding to distance vision. A contact lens according to an embodiment of the present invention in which the central region has a substantially constant lens power corresponding to distance vision can provide high acuity distance vision under bright light conditions when the pupil is at its smallest size. Bright light conditions generally correspond to daytime outdoor environments where the wearer generally has a greater need for distance vision than near vision, and therefore high acuity distance vision is generally more advantageous to the wearer than high acuity near vision under such conditions. Alternatively, the central region may have a lens power corresponding to near vision. Additionally, the central region may have a lens power stronger than the near vision correction required by the lens wearer. For example, the power of the central region can be +0.25D to +1.25D stronger than the near vision correction required by the lens wearer.

[0034] The lens may include a transition region. The transition region may surround the central region. The outer region may surround the transition region. The power of the transition region may vary to provide a smooth transition between the central region and the outer region. Embodiments of the invention that provide a smooth transition between the central region and the outer region may allow easier lathe manufacture of lenses, molds for such lenses, and inserts for such lens molds. In this case, it will be appreciated by those skilled in the art that smooth in this context means that the lens profile must be smooth enough to be produced using a lathe.

[0035] The lens may include a second surface forming a second surface power map. The second surface may be a surface opposite to the first surface of the ophthalmic lens. The second surface power map may not vary periodically over the portion of the lens. Thus, the portion may have a helical lens power map throughout. Contact lenses according to embodiments of the present invention in which the optical zone includes a helical lens power map may provide a substantially constant ratio of the first lens power to the second lens power in the presence of varying pupil sizes.

[0036] It will be appreciated that the second surface power map can have a substantially constant power of +0D across the power map. For purposes of this description, the second surface of the lens will still be considered to form a second surface power map, even if the second surface power map does not ultimately provide any focusing or vision correction.

[0037] The second surface power map can vary substantially periodically radially outward from the center of said portion, and the period of the radial variation of the second surface can be greater than 100 microns, preferably greater than 200 microns, more preferably greater than 400 microns, and even more preferably greater than 800 microns.

[0038] The second surface power map can vary substantially periodically in an angular direction about the optical axis of the lens. The period of the angular variation of the second surface can be greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and even more preferably greater than 36 degrees.

[0039] That is, in an embodiment, the radial variation may have a period greater than 100 microns and the angular variation may have a period greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and even more preferably greater than 36 degrees. In another embodiment, the radial variation may have a period greater than 200 microns and the angular variation may have a period greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and even more preferably greater than 36 degrees. In another embodiment, the radial variation may have a period greater than 400 microns and the angular variation may have a period greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and even more preferably greater than 36 degrees. In another embodiment, the radial variation may have a period greater than 800 microns and the angular variation may have a period greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and even more preferably greater than 36 degrees.

[0040] The period and phase of the radial and angular variations of the second surface may be the same as the first surface. Thus, the second surface power map may also include a spiral, e.g., a spiral that matches the first surface. In such an embodiment, the overall lens power map also comprises a spiral. An embodiment of the present invention comprising a contact lens having a spiral lens power map may provide a substantially constant ratio of the first lens power to the second lens power in the presence of varying pupil sizes.

[0041] Each of the power maps formed on the first and second surfaces may include a spiral. The spiral provided by the first surface and the spiral provided by the second surface may twist in opposite directions. Thus, the first and second surface power maps may be said to comprise counter-rotating spirals. The spiral provided by the first surface power map and the spiral provided by the second surface power map may be the same except for the opposite twist directions. An embodiment of the present invention in which the first and second surface power maps comprise counter-rotating spirals may provide a lens power map that approximates a dartboard pattern of alternating annular rings. It will be appreciated by those skilled in the art that the lens power map is formed by the superposition of the power maps of each of the first and second surfaces. It will also be appreciated that a pseudo-dartboard pattern is thus provided by the combination of the first and second surface power maps, each of which retains the ease of manufacture advantages discussed above. Thus, such an embodiment may allow easier manufacturing of lenses having a pseudo-dartboard power map using a lathe.

[0042] The lens power map can include multiple sections. The multiple sections can provide either a first power corresponding to distance vision or a second power corresponding to near vision. Thus, the first power can be between 0 diopters (D) and -10D. In some embodiments, the first power is from -0.25D to -6.00D. The second power provided in the lens of the present invention can be stronger than the first power of the lens, for example, the second power can be 1D to 5D stronger than the first power. In some embodiments, the second power can be 1D to 4D stronger than the first power. In yet another embodiment, the second power can be 2D to 3D stronger than the first power. Furthermore, in some embodiments, the second power may vary, thus may occur when providing discrete defocus segments with stronger powers than the first power, for example, such that some of the segments may have a second power of +1D, some segments may have a second power of +2D, and some segments may have a second power of +3D. The variation in the second power may occur within the same arm or may occur within different arms. These zones may be arranged on the lens to alternate radially and / or angularly between the first and second powers.

[0043] The multifocal lens may be a myopia suppressing lens. Thus, the multifocal lens may be configured to reduce the progression of myopia in individuals with eyes that can accommodate. The multifocal lens may be suitable for correcting presbyopia. Thus, the multifocal lens may be configured to provide distance and near vision corrections to individuals with eyes that cannot accommodate sufficiently (e.g., individuals aged 40 or older). The multiple zones may provide either a power corresponding to high acuity distance vision or a power corresponding to high acuity near vision. The zones may be arranged on the lens to alternate radially and / or angularly between high acuity near and distance vision.

[0044] A contact lens according to an embodiment of the present invention may include a ballast for determining the orientation of the lens when placed on the wearer's eye. Such a ballast may be provided by a peripheral zone of the contact lens. In certain embodiments of the present invention, the contact lens may provide a particular advantage to the wearer in a given orientation. An embodiment of the present invention incorporating a ballast in the contact lens will rotate to a predetermined rest angle under the action of the wearer's eyelid when placed on the wearer's eye, for example, the ballast may be a wedge and the rotation may result from the action of the eyelid on the wedge. By placing the ballast in the contact lens, it is possible to ensure that this rest angle corresponds to an orientation of the lens that provides a particular advantage to the wearer.

[0045] The present invention provides a method of manufacturing a multifocal ophthalmic lens (e.g., a contact lens) according to a second aspect. The method comprises operating a lathe to shape a first surface of one of a lens (e.g., a contact lens), a mold for a lens (e.g., a mold for a contact lens), or an insert for manufacturing a mold for a lens (e.g., an insert for a mold for a contact lens). The first surface is shaped to vary over at least a portion of the lens to form a first surface power map that comprises a spiral. The first surface is shaped such that the surface power map varies substantially periodically both radially outward from the optical axis of the lens and in angular directions thereabout. The period of the radial variation is greater than 100 microns. The period of each of the angular variations is greater than 6 degrees.

[0046] The method may comprise operating a lathe to shape at least a portion of the surface of the lens. Alternatively or additionally, the method may comprise operating a lathe to shape at least a portion of the surface of a mold for the lens. Alternatively or additionally, the method may comprise operating a lathe to shape at least a portion of the surface of an insert for the manufacture of a mold for the lens. It will be appreciated by those skilled in the art that the more the object of lathe shaping is removed from the lens, the less the definition of the features that will be reproduced on the resulting lens. Thus, for example, shaping the surface of the lens with a lathe allows for the definition of more surface features than would be achievable when shaping the surface of the mold for the lens with a lathe. The method may further comprise operating a lathe to shape a second surface of the lens, mold, or insert. The second surface may be shaped to vary over at least the portion of the lens to form a second surface power map comprising a spiral. The second surface may be shaped such that the second surface power map varies substantially periodically both radially outward from the optical axis of the lens and angularly thereabout. The period of the radial variation may be greater than 100 microns. The period of the angular variation may be greater than 6 degrees. The second surface may be shaped such that the second surface power map varies as a mirror image of the first surface. The second surface may be shaped such that the spiral formed by the first surface power map twists in an opposite direction to that formed by the second surface power map.

[0047] The lens may be a contact lens. In such embodiments, the above-mentioned portion of the lens may correspond to the optical zone of the contact lens. In such cases, it will be appreciated that references to the optical zone of a mold or an insert for a mold refer to the portion of the mold that corresponds to the optical zone of a lens produced using that mold or insert.

[0048] Lenses according to the invention, e.g., contact lenses, can be formed by a cast molding process, a spin casting process, or a lathing process, or a combination thereof. As will be understood by those skilled in the art, cast molding refers to the molding of lens members by placing a lens-forming material between a female mold member having a concave lens member-forming surface and a male mold member having a convex lens member-forming surface.

[0049] In embodiments where the ophthalmic lens comprises a contact lens, the contact lens material is visually clear (although it may include handling tinting) when used as part of a contact lens or as the entire contact lens. The contact lens material may be a hydrogel material, a silicone hydrogel material, or a silicone elastomer material, as understood in the art. In other words, the contact lens of the present invention can comprise, consist essentially of, or consist of a hydrogel material, a silicone hydrogel material, or a silicone elastomer material. As understood in the contact lens field, a hydrogel is a material that retains water in an equilibrium state and is absent of silicone-containing chemicals. A silicone hydrogel is a hydrogel that includes silicone-containing chemicals. The hydrogel and silicone hydrogel materials used herein have an equilibrium water content (EWC) of at least 10% to about 90% (wt / wt). In some embodiments, the hydrogel or silicone hydrogel material has an EWC of about 30% to about 70% (wt / wt). In comparison, the silicone elastomer materials used herein have a water content of about 0% to less than 10% (wt / wt). Typically, the silicone elastomer materials used with the method or device of the present invention have a water content of 0.1% to 3% (wt / wt). Alternatively, examples of contact lenses of the present invention can be made from a rigid gas-permeable material such as polymethylmethacrylate (PMMA).

[0050] The method can include forming a contact lens in a molding assembly that includes a first mold part and a second mold part assembled together. In the case of a hydrogel lens or a silicone hydrogel lens, the lens can be produced by polymerizing a hydrogel or silicone hydrogel lens formulation with a polymerization initiator in a lens-shaped cavity formed between the first and second mold parts. In the case of a silicone elastomer lens, the lens can be produced by curing, vulcanizing, or catalyzing the reaction of a liquid silicone elastomer material in a lens-shaped cavity formed between the first and second mold parts, such as by hydrosilylation. The surface of each mold part that forms the contact lens-shaped cavity can be convex, concave, flat, or a combination thereof. After the contact lens is formed, the two mold parts are separated such that the contact lens remains attached to one surface of the mold parts. As a result, a contact lens is provided on the surface of the first or second mold part. In some other embodiments, it may be desirable to place a lens member on a face of a mold part that was not used to produce the first lens member, but this may require additional steps to achieve the desired alignment of the member relative to the mold part. The lenses can then be removed from the attached mold part and further processed, such as by extraction and hydration, inspected, packaged, and sterilized.

[0051] FIG. 1 illustrates a contact lens 10 according to an embodiment of the present invention. The contact lens 10 comprises an optical zone 11 and a peripheral zone 13. The optical zone 11 comprises the portion of the lens through which the wearer of the contact lens sees. The optical zone 11 forms a lens designed to provide vision correction to the wearer. The peripheral zone 13 surrounds the optical zone 11 and does not provide any vision correction to the wearer. The peripheral zone 13 can perform other functions. For example, the peripheral zone 13 can function to help maintain the contact lens on the wearer's eye. In some embodiments of the present invention, the peripheral zone 13 can include a ballast to maintain a predetermined orientation of the contact lens on the wearer's eye.

[0052] The two surfaces of the contact lens are shaped to vary across the optical zone 11 to form a first and a second surface power map. The first and second surface power maps together form a lens power map. Thus, the optical zone can be said to provide a first surface power map, a second surface power map, and a lens power map. Within the optical zone, the power map can include one or more distinct regions. The exemplary contact lens shown in FIG. 1 comprises a central region 15, an outer region 17, and a transition region 19. The outer region 17 surrounds the transition region 19. The transition region 19 surrounds the central region 15. The central region 15 and the outer region 17 can be provided with different lens power arrangements to provide different vision corrections. The transition region 19 can function to provide a smooth transition between the central region 15 and the outer region 17. It will be appreciated that the contact lens shown in FIG. 1 is provided by way of example only, and other contact lenses according to the invention can include more or fewer regions. For example, some contact lenses according to embodiments of the present invention may exclude a transition region, or may even include only a single region throughout the optical zone 11. Other contact lenses according to embodiments of the present invention may include additional regions, for example, formed as concentric circles.

[0053] According to a first exemplary embodiment of the present invention, a multifocal contact lens is provided. It will be appreciated that alternative embodiments may comprise an intraocular lens or a spectacle lens. The multifocal contact lens comprises a first surface and a second surface. In this exemplary embodiment, the first surface comprises an outer surface of the contact lens and the second surface comprises an inner surface of the contact lens. It will be appreciated by those skilled in the art that the outer surface is the convex surface of the contact lens adjacent the wearer's eyelid and the inner surface is the concave surface of the contact lens adjacent the wearer's eye.

[0054] A portion of the first surface can be said to be shaped to form a first surface power map. In this exemplary embodiment, this portion corresponds to the optical zone of the contact lens. That is, the first surface of the optical zone can be said to form the first surface power map. It will be appreciated by those skilled in the art that the first surface power map represents the modification provided by the shape of this surface to the overall contact lens power map. Thus, a contact lens having two surfaces (an inner surface and an outer surface) will have two surface power maps, the combination of which determines the overall contact lens power map.

[0055] FIG. 2 shows a first surface power map 100 of the above-mentioned portion of the first surface of a contact lens. The first surface power map 100 forms a spiral. The spiral comprises a plurality of arms 101 (four in this example). Each of the arms 101 comprises a peak arm 101a and a trough arm 101b. It will be appreciated that the peak arm 101a is the arm with a positive deviation from the average power of the surface power map (or the periodically varying region of the surface power map) and the trough arm 101b is the arm with a negative deviation from the average power of the surface power map (or the periodically varying region of the surface power map). The spiral is formed by substantially periodically varying the power both radially outward from and angularly about the optical axis of the contact lens. It will be appreciated that the optical axis of the lens corresponds to the optical axis of the optical zone of the lens. The power varies between a first lens power and a second lens power. The multifocal contact lens of this exemplary embodiment has a base lens power of -3.0D with an add power of +3.0D. Thus, the first lens power is -3.0D and the second lens power is +0D. Such a contact lens may be suitable for patients who suffer from both myopia and hyperopia. The base lens power of -3.0D allows the wearer to correct his / her distance vision, while the add power of +3.0D serves to correct his / her near vision, when the wearer is unable to fully accommodate. It will be appreciated by those skilled in the art that the specific values ​​of the first lens power and the second lens power (and thus the base lens power and the add power) presented are merely examples, and the actual values ​​used in a given context will be determined by the needs of the intended wearer.

[0056] In this exemplary embodiment, the period of the radial variation is 1.2 mm and the period of the angular variation is 90 degrees. However, it will be appreciated that other periods of radial and / or angular variation may be used in alternative embodiments. The period of the radial variation need only be greater than 100 microns and the period of the angular variation need only be greater than 6 degrees.

[0057] In this particular embodiment, the power varies smoothly both radially and angularly across the first surface power map 100 as a substantially sinusoidal wave. Having the surface power map vary smoothly across the aforementioned portion of the lens allows for easier manufacturing using a contact lens lathe or an apparatus for manufacturing contact lenses (e.g., a mold or an insert for a mold). However, in alternative embodiments, the power can vary according to other waveforms. For example, the power can vary as a square wave or a rounded square wave in one or both of the radial and angular directions. Thus, in alternative embodiments, the power does not necessarily vary smoothly across the aforementioned portion of the lens.

[0058] In this exemplary embodiment, the positive and negative excursions of the sine wave are of equal length such that the sine wave can be said to have a 50% duty cycle. Alternative embodiments include variations having other duty cycles. Thus, in such embodiments, the positive excursion may be of a different length than the negative excursion.

[0059] It will be appreciated that the width of the helix arms 101 is determined at least in part by the ratio of the period of radial variation to the period of angular variation. In this exemplary embodiment, each helix arm 101 is approximately 500 microns in width. It will be appreciated that alternative embodiments may incorporate arms 101 having different widths. Similarly, it will be appreciated that the width of an arm 101 is defined as its perpendicular width.

[0060] Similarly, in the exemplary embodiment, the period of each of the radial and angular variations is substantially constant across the portion, however, in alternative embodiments, the period of at least one of the radial and angular variations may vary according to one or both of the radial distance from the center of the portion and the angular position about the center of the portion.

[0061] In alternative embodiments, the period of the angular variation is less than 180°. Those skilled in the art will appreciate that the period of the angular variation determines the number of arms 101 on the helix. Thus, in such an embodiment, the helix comprises at least two arms. Thus, it will also be appreciated that a certain value of the angular variation, particularly a unit fraction of 360°, can be particularly advantageous in providing a surface power map that does not have angular discontinuities.

[0062] In this exemplary embodiment, each arm 101 of the spiral twists through an angle of 270 degrees (or 0.75 turns). In alternative embodiments of the invention, each arm 101 of the spiral can twist through between a quarter turn (90 degrees) and 40 turns.

[0063] In this particular embodiment, the first surface power map 100 comprises a central region 103 and an outer region 105. The central region 103 immediately surrounds the optical axis of the contact lens. The outer region 105 surrounds the central region 103. The power of the central region 103 does not vary periodically across this region, e.g., may be substantially constant. The outer region 105 comprises a helical power map and thus comprises angular and radial variations in power.

[0064] In an alternative embodiment of the invention, each arm 101 of the spiral extends from the center of the aforementioned portion of the lens to the periphery of this portion, and thus such an embodiment does not include distinct central and outer regions.

[0065] As mentioned above, in this exemplary embodiment, the aforementioned portions of the lens correspond to the optical zone of the contact lens. In this exemplary embodiment, the central region 103 has a diameter of 2 mm, which corresponds to 25% of the 8 mm diameter of the optical zone. The optical zone through which the wearer sees provides the first surface power map shown in FIG. 2. In addition, the contact lens may include a surrounding peripheral zone that does not provide additional focusing or vision correction, but serves only to help maintain the contact lens in place on the wearer's eye. The diameter of the central region may be less than 25% of the diameter of the optical zone. However, it will be appreciated that in alternative embodiments of the invention, the diameter of the central region 103 may have other values. Similarly, it will be appreciated that the ratio of the diameter of the central region 103 to the diameter of the optical zone may also have other values. For example, the diameter of the central region 103 may be less than 30% of the diameter of the optical zone.

[0066] In an embodiment, the central region 103 may be smaller than the minimum pupil size of the wearer of the contact lens. Such an embodiment maintains multifocal vision even when the wearer's pupil is constricted to its minimum size. If the central region 103 is larger than the minimum pupil size, then only the central region 103 will be positioned over the wearer's entrance pupil when the wearer's pupil is constricted to its minimum size. Because the power of the central region 103 does not vary as a spiral across this region, the lens will not provide multifocal vision for any pupil size smaller than the central region 103.

[0067] Significantly, in this exemplary embodiment, the central region 103 provides a lens power corresponding to distance vision. Generally, bright conditions correspond to outdoor environments. Thus, the wearer's pupils generally constrict more when outdoors than when indoors. Furthermore, the wearer generally has a greater need for distance vision when outdoors than when indoors. Having the central region 103 with a lens power corresponding to distance vision can enable the contact lens to provide high acuity distance vision even when the wearer's pupils are constricted to their minimum size.

[0068] This exemplary embodiment further comprises a transition region 107. The transition region 107 surrounds the central region 103. The outer region 105 surrounds the transition region 107. The power of the transition region 107 varies to provide a smooth transition between the central region 103 and the outer region 105. It will be appreciated that such a transition region 107 is not required, and thus alternative embodiments do not include the transition region 107. It will be appreciated that "smooth" in this context is defined as being smooth enough that the corresponding lens curvature can be reproduced by a lathe. In this exemplary embodiment, the transition region is approximately 300 microns in width. However, it will be appreciated that transition regions of other widths can be used.

[0069] It will be appreciated by those skilled in the art that the second surface of the aforementioned portion of the contact lens (i.e., the second surface of the optical zone of the contact lens in this exemplary embodiment) forms a second surface power map. In this exemplary embodiment, the second surface power map does not vary periodically across the portion. Thus, the contact lens has a helical lens power map. Thus, the contact lens provides only a small change in the ratio of near to distance accommodation as the wearer's pupil changes size.

[0070] In this exemplary embodiment, the first surface corresponds to an outer surface of the contact lens and the second surface corresponds to an inner surface of the contact lens, although one of ordinary skill in the art will appreciate that in alternative embodiments, the first surface can correspond to an inner surface and the second surface can correspond to an outer surface. Thus, in an embodiment, the inner surface comprises a surface power map that forms a spiral and the outer surface comprises a substantially flat surface power map.

[0071] According to a second exemplary embodiment of the present invention, there is provided a second multifocal contact lens, the first surface of which is identical to that of the contact lens of the first embodiment.

[0072] In this embodiment, the second surface power map 200 (FIG. 3) also varies substantially periodically both angularly around the center of the portion and radially outward from the center. Thus, the second surface power map 200 also comprises a spiral. As with the first surface, the spiral comprises a number of arms 201, including peak arms 201a and trough arms 201b. In this exemplary embodiment, the period of the radial and angular variations of the second surface power map 200 is the same as the first surface power map 100. However, it will be appreciated by those skilled in the art that alternative embodiments may incorporate variations on the second surface power map 200 having a different period than one or both of the periods of the first surface power map 100. As in the above case, in alternative embodiments, the period of the angular variations of the second surface power map 200 is greater than 6 degrees. Similarly, in alternative embodiments, the period of the radial variations of the second surface power map 200 may be greater than 100 microns. In this exemplary embodiment, the second surface power map 200 also comprises a central region 203 , an outer region 205 , and a transition region 207 .

[0073] In this exemplary embodiment, the spiral formed by the second surface power map 200 twists in the opposite direction to the spiral formed by the first surface power map 100 of Figure 2. In this particular embodiment, the spiral provided by the first surface power map 100 and the spiral provided by the second surface power map 200 are the same except for the opposite twist directions. The power map of the contact lens is determined by the superposition of the power map of the first surface power map 100 and the power map of the second surface power map 200. Figure 4 shows the power map of the contact lens of the second embodiment.

[0074] The superposition of the two counter-rotating spirals formed by the first surface power map 100 and the second surface power map 200 results in a lens power map that approximates a pseudo-dartboard pattern of alternating annular rings. The lens power alternates approximately between the first lens power and the second lens power both radially and angularly. Because the power alternates angularly between the first lens power and the second lens power, the contact lens also provides a monotonic variation in the ratio of the first lens power to the second lens power as the wearer's pupil constricts. Thus, the contact lens 300 also provides improved multifocal vision in the presence of variable light conditions.

[0075] Because both the first surface power map 100 and the second surface power map 200 include a central region, an outer region, and a transition region, the overall lens power map of the contact lens 300 also comprises a central region 303, an outer region 305, and a transition region 307.

[0076] Figure 5 shows a contact lens according to a third embodiment of the present invention. The third embodiment is substantially the same as the second embodiment, except that the spiral provided by the second surface power map is rotated through a phase shift of 45 degrees. As can be seen from Figure 5, the superposition of the first and second surface power maps with two counter-rotating spirals results in a pseudo-dartboard power map similar to the second embodiment. Thus, the superposition of the two counter-rotating spirals results in a pseudo-dartboard lens power map regardless of the relative phase of the first and second spirals.

[0077] Here again, the total power map of the contact lens 400 comprises a central region 403, an outer region 405 and a transition region 407. According to a fourth embodiment of the present invention, a spectacle lens is provided. The spectacle lens comprises substantially the same helical power map as described with respect to the first embodiment of the present invention. However, it will be appreciated by those skilled in the art that the spectacle lens does not comprise an optical zone in the same sense as the contact lens of the first embodiment. Therefore, in this case, the above-mentioned portion of the lens does not correspond to an optical zone. It will further be appreciated by those skilled in the art that the characteristics of the lens profile defined above with respect to the optical zone of the contact lens can be applied in the same way with respect to the corresponding portion of the spectacle lens of this embodiment. It will be appreciated that an alternative embodiment of the present invention comprises a spectacle lens having substantially the same surface power map as described with respect to the second and third embodiments of the present invention.

[0078] According to a fifth embodiment of the present invention there is provided an intraocular lens comprising substantially the same helical power as described with respect to the first embodiment of the present invention. It will be appreciated that alternative embodiments of the present invention comprise intraocular lenses having substantially the same surface power maps as described with respect to the second and third embodiments of the present invention.

[0079] FIG. 6 shows a flow diagram illustrating steps of a method 500 for manufacturing a lens, for example a contact lens, according to a sixth embodiment of the present invention.

[0080] The first step of method 500, represented by element 501, comprises operating a lathe to shape a first surface of one of a lens, a mold for a lens, or an insert for manufacturing a mold for a lens. The first surface is shaped to vary across at least a portion of the lens (e.g., the optical zone of a contact lens) to form a first surface power map. The first surface power map comprises a spiral and varies substantially periodically both radially outward from and angularly about the optical axis of the contact lens. The period of the radial variation is greater than 100 microns. The period of the angular variation is greater than 6 degrees.

[0081] An optional second step of method 500, represented by element 503, comprises operating a lathe to shape a second surface of a lens, a mold for a lens, or an insert for producing a mold for a lens. The second surface is shaped to vary over at least the aforementioned portion of the lens to form a second surface power map. The second surface power map comprises a spiral and varies substantially periodically both radially outward from and angularly about the optical axis of the contact lens. The period of the radial variation is greater than 100 microns. The period of each of the angular variations is greater than 6 degrees.

[0082] The second surface can be shaped to vary as a mirror image of the first surface, or alternatively, the second surface can be shaped such that the helix formed on the first surface twists in an opposite direction to the helix formed on the second surface.

[0083] When the first surface (and the second surface if the second step 503 has been performed) is included on a mold for a lens or an insert for a mold for a lens, the method 500 can include an optional third step represented by element 505. The third step 505 comprises manufacturing a lens using the mold of the insert for the mold for the lens.

[0084] Although the invention has been described and illustrated with reference to specific embodiments, it will be appreciated by those skilled in the art that the invention is susceptible to many different variations not specifically exemplified herein. By way of example only, certain possible variations are now described below.

[0085] In the first embodiment, the lens with a helical lens power map is provided by a first surface power map of the contact lens with a helix and a second surface power map of the contact lens with a substantially constant power. However, in an alternative embodiment, the lens with a helical lens power map is provided by each of the first surface power map and the second surface power map with a helix. In such an embodiment, the period and phase of the radial and angular variations of the second surface power map are the same as those of the first surface power map. Thus, the first and second surface power maps can be said to comprise mirror images of each other. Thus, the first and second surface power maps overlap to form a single helical power map, thereby forming a contact lens with a helical lens power map.

[0086] In all of the first, second, and third embodiments, each of the surface power maps of the contact lens comprises a central region having a substantially constant power, an outer region incorporating a helical power profile, and a transition region providing a smooth transition between the central and outer regions. However, some alternative embodiments do not incorporate a transition region. Yet other alternative embodiments do not incorporate distinct central and outer regions. Instead, in such embodiments, the helical profile extends all the way from the center of the aforementioned portion of the lens to the radial periphery of this portion.

[0087] In the first embodiment, the spiral formed by the first surface power map twists in a counterclockwise direction. However, in an alternative embodiment, the spiral formed by the first surface power map twists in a clockwise direction. In an embodiment in which mirror image spirals are formed on the first and second surface power maps, these spirals can rotate in either a clockwise or counterclockwise direction. Similarly, in the second embodiment, the spiral formed on the first surface power map twists in a counterclockwise direction and the spiral formed on the second surface power map twists in a clockwise direction. However, in an alternative embodiment, the spiral formed on the first surface power map twists in a clockwise direction and the spiral formed on the second surface power map twists in a counterclockwise direction.

[0088] In some embodiments of the present invention, the spiral formed on one or both of the first and second surface power maps changes its rotation direction at a predetermined radial distance from the center of the portion. For example, the spiral can rotate clockwise between the center of the portion and a predetermined radial distance and counterclockwise beyond the predetermined radial distance. In some embodiments, the lens incorporates more than one change in the rotation direction of the spiral. Thus, the spiral can change, for example, from clockwise to counterclockwise and then back to clockwise again. It will be appreciated by those skilled in the art that the lens can incorporate any number of spiral rotation direction changes. It will also be appreciated that each of these direction changes can occur at any selected radial distance from the center of the portion. Thus, the power map can comprise annular rings that alternate between clockwise and counterclockwise rotating spirals.

[0089] In some embodiments, there is a region where the power map does not change as a spiral between a plurality of regions of the ophthalmic lens having different rotation directions. For example, this region can have a substantially constant power. For example, the lens (or surface) power map can change as a clockwise spiral to a first radial distance from the center of the above-mentioned portion, followed by a region of substantially constant power, and then change as a counterclockwise spiral. Thus, the power map can appear to include, for example, a plurality of annular rings that alternate between a spiral power and a substantially constant power, and the spiral region also alternates between a clockwise rotation and a counterclockwise rotation.

[0090] Similarly, in some embodiments, the spiral can be interrupted by one or more regions, e.g., rings, where the power map does not change as the spiral. For example, the regions can have a substantially constant power. Thus, for example, the power map can comprise annular rings that alternate between a spiral power and a substantially constant power. In such an embodiment, the spiral can change rotational direction between each interruption, or can continue in the previous rotational direction. Thus, the spiral can maintain a constant rotational direction across the lens, but may be interrupted by regions of substantially constant lens power.

[0091] Although embodiments of the invention have been described above with respect to methods of manufacturing contact lenses, molds for contact lenses, or inserts for molds for contact lenses using a lathe, it will be appreciated that other manufacturing methods are possible. In particular, the molds or inserts may be manufactured using additive manufacturing techniques, for example by 3D printing.

[0092] Wherever the above description refers to an integer or element having a known, obvious or foreseeable equivalent, such equivalent is incorporated herein as if it were individually set forth. Reference should be made to the claims to determine the true scope of the invention, which should be interpreted as including all such equivalents. Similarly, it will be recognized by the reader that integers or features of the invention described as being preferred, advantageous, convenient, etc. are optional and do not limit the scope of the independent claims. It is further to be understood that such optional integers or features, while being possible benefits in some embodiments of the invention, may be undesirable in other embodiments and therefore may be absent. [Explanation of symbols]

[0093] 10. Contact Lenses 11 Optical Zone 13 Surrounding Zone 15 Central area 17 Outer area 19 Transition Zone

Claims

1. A multifocal ophthalmic lens, a first surface of the lens varying across at least a portion of the lens to form a first surface power map; the first surface power map comprises a spiral having powers that vary periodically radially outward from an optical axis of the lens with a constant period greater than 100 microns and that vary periodically in an angular direction about the optical axis of the lens; The period of the angular orientation variation is greater than 6 degrees. A multifocal ophthalmic lens.

2. The ophthalmic lens is a contact lens, the first surface varies across an optical zone of the contact lens to form the first surface power map; 2. The multifocal ophthalmic lens according to claim 1.

3. A multifocal ophthalmic lens according to claim 1 or 2, characterized in that the power varies smoothly across the portion.

4. 4. The multifocal ophthalmic lens of claim 3, wherein the power varies both radially and angularly as one of a rounded square wave and a sine wave.

5. 3. A multifocal ophthalmic lens according to claim 1 or 2, characterized in that the power varies as a square wave both radially and angularly.

6. A multifocal ophthalmic lens according to any one of claims 1 to 5, characterized in that the periods of the angular variations are each constant across the portion.

7. A multifocal ophthalmic lens as claimed in any one of claims 1 to 5, characterized in that the period of the angular variation varies according to one or both of the radial distance from the optical axis of the lens or the angular position around the optical axis of the lens.

8. the lens having a central region immediately surrounding the optical axis of the lens and an outer region surrounding the central region; the power of the central region does not vary periodically across the central region; the outer region comprises the angular and radial variations in power. The multifocal ophthalmic lens according to any one of claims 1 to 7.

9. A multifocal ophthalmic lens according to claim 8, characterized in that said central region has a diameter less than 50% of the diameter of said portion.

10. the lens comprises a transition region, the transition region surrounding the central region, and the outer region surrounding the transition region; the power of the transition region varies to provide a smooth transition between the central region and the outer region; 10. The multifocal ophthalmic lens according to claim 8 or 9.

11. the lens comprising a second surface that varies across the portion of the lens to form a second surface power map; the second surface power map comprises a spiral having power that varies periodically radially outward from an optical axis of the lens and angularly about the optical axis of the lens; a period of variation of the second surface power map radially outward from an optical axis of the lens is greater than 100 microns; a period of the angular direction variation of the second surface power map is greater than 6 degrees; The multifocal ophthalmic lens according to any one of claims 1 to 10.

12. the first surface power map and the second surface power map each comprise a spiral; the helix provided by the first and second surface power maps twists in opposite directions. A multifocal ophthalmic lens according to claim 11.

13. 13. The multifocal ophthalmic lens according to any one of claims 1 to 12, which is a myopia suppression lens.

14. 1. A method for making a multifocal ophthalmic lens, comprising: a first surface of at least one of a lens, a mold for a lens, or an insert for manufacturing a mold for a lens; the first surface varies across at least a portion of the lens to form a first surface power map; the first surface power map comprises a spiral; the first surface power map varies periodically radially outward from the optical axis of the lens with a constant period greater than 100 microns and varies periodically in an angular direction about the optical axis of the lens; and The period of the angular orientation variation is greater than 6 degrees. operating the lathe to form the 23. A method comprising:

15. A second surface of the lens, the mold, or the insert. the second surface varies across the portion of the lens to form a second surface power map; the second surface power map comprises a spiral; the second surface power map varies periodically radially outward from the optical axis of the lens with a constant period greater than 100 microns and varies periodically in an angular direction about the optical axis of the lens; and The period of the angular orientation variation is greater than 6 degrees.

15. The method of claim 14, further comprising the step of operating a lathe to form the shaping member as follows:

16. 1. A method for improving vision in an individual, comprising: Providing a multifocal ophthalmic lens according to any one of claims 1 to 13 to an individual in need of improved vision; 23. A method comprising:

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