Multifocal ophthalmic lenses and related methods

Abstract

A multifocal ophthalmic lens has a surface that varies across at least a portion of the lens to form a surface power pattern. The surface power pattern includes a spiral having a degree that varies radially outward from the optical axis of the lens and angularly around the optical axis of the lens, typically periodically. The period of the radial variation is greater than 100 micrometers, and the period of the angular variation is greater than 6 degrees. Methods of manufacturing and using the multifocal ophthalmic lens are also described.

Description

Technical Field

[0001] This invention relates to multifocal ophthalmic lenses. More specifically, but not exclusively, this invention relates to multifocal ophthalmic lenses having a spiral surface power pattern, as well as methods of manufacturing such lenses and methods of using such lenses. Background Technology

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

[0003] In multifocal contact lenses, multiple regions can be formed as concentric circles centered on the optical axis of the lens, alternating between the first and second lens powers. Therefore, in this example, the power map or power profile of a typical multifocal contact lens includes at least two alternating concentric circles for the first and second lens powers. However, such contact lenses can present challenges for wearers under variable light conditions. In lower light conditions, the wearer's pupil dilates to provide a larger aperture for incident light, increasing the amount of light entering the eye and thus improving low-light vision. As conditions brighten, the pupil constricts to provide a smaller aperture, thus limiting the amount of light entering the eye. As the wearer's pupil dilates and constricts, the number of concentric rings on the contact lens that align with the wearer's entrance pupil changes. With pupil dilation, a greater number of concentric rings align with the wearer's entrance pupil. Similarly, with pupil constriction, a smaller number of concentric rings align with the wearer's entrance pupil. Because the concentric rings alternate between the first and second lens powers, the ratio of the first to second lens powers, positioned across the wearer's pupil, changes as the pupil constricts and dilates. As the pupil constricts, the number of either the near or far focusing lenses decreases until the pupil contracts to the diameter of the next smallest concentric circle. At this point, the number of the other lens decreases again until the pupil contracts to the diameter of the next smallest concentric circle. This cycle repeats with pupil constriction, causing the near-to-far focusing ratio to change with pupil constriction. It will be understood that the same effect occurs in the opposite direction as the pupil dilates. These changes in the near-to-far focusing ratio can cause the wearer to become distracted or even lose multifocal vision. Generally, the more the wearer's pupil constricts, the more severe this change in ratio becomes. Therefore, especially under bright conditions, when the pupil constricts to near its minimum size, wearers of such multifocal contact lenses may find that the ability of the multifocal contact lenses to provide high acuity in both near and far vision is impaired. Bi-zone multifocal contact lenses, one of the most popular designs among multifocal contact lenses, further exacerbate this effect. Bi-zone multifocal contact lenses consist of an inner ring for the first lens power and a single outer ring for the second lens power. Therefore, the greater the pupil constriction of the wearer's pupil with this type of lens, the smaller the second lens power's entry pupillary position becomes across the wearer's pupil. In some cases, the pupil may even constrict to the point where there is no second lens power across the wearer's pupillary position, resulting in complete loss of multifocal vision. Other multifocal contact lenses use a similar principle, but instead of lenses with alternating concentric rings, they incorporate aspherical power profiles to provide a more gradual transition from near to far vision. These lenses are also affected by changes in the ratio of the lens power across the wearer's pupillary position as the wearer's pupil dilates and constricts.

[0004] The present invention seeks to alleviate the problems mentioned above. Alternatively or additionally, the present invention seeks to provide an improved multifocal ophthalmic lens. Summary of the Invention

[0005] According to a first aspect, the present invention provides a multifocal ophthalmic lens. The surface of the ophthalmic lens varies across at least a portion of the lens to form a surface power map. The surface power map includes a spiral having a degree that varies radially outward from the optical axis of the lens and angularly around the optical axis of the lens in a generally periodic manner. The period of the radial variation is greater than 100 micrometers, and the period of the angular variation is greater than 6 degrees.

[0006] Contact lenses with a surface power profile including a spiral can provide a more stable ratio of near to far focusing vision as the wearer's pupil size changes. As light conditions change, the wearer's pupil dilates and constricts to regulate the amount of light entering the eye. As conditions brighten, the pupil constricts to reduce the amount of light allowed into the eye. As conditions darken, the pupil dilates to allow more light into the eye. Existing multifocal contact lenses may use alternating concentric rings of near and far focusing, such as a central circle for far focusing surrounded by an outer circle for near focusing, or existing multifocal contact lenses may use an aspherical power profile to provide multifocal vision. As discussed above, these contact lenses experience changes in the ratio of near to far focusing vision provided across the wearer's entrance pupil as the wearer's pupil dilates and constricts. These changes can distract the wearer and even lead to loss of multifocal vision.

[0007] A helical power diagram maintains a constant ratio of near to far focusing over the entire diameter encompassing the helix. Therefore, contact lenses with a helical power diagram can maintain either a substantially constant ratio (where the helix covers the entire optical zone of the lens) or a monotonically varying ratio of near to far focusing as the pupil constricts or dilates (where the helix covers only the radial sub-section of the lens's optical zone). Thus, contact lenses with a helical power diagram provide improved multifocality in the presence of variable light conditions.

[0008] Those skilled in the art will understand that, in the case of a smooth change in the power curve (e.g., as a sine curve), the power curve will include lens powers other than a first lens power corresponding only to near vision and a second lens power corresponding to far vision. In such cases, the power curve will also include a region having lens powers between the first and second powers. It will be understood that this does not affect or diminish the advantage described above of providing a consistent and stable change in the increase in power across the wearer's entrance pupil position. Those skilled in the art will understand that this advantage stems from the fact that the composition of the increase in power at a specific radius for the spiral power curve does not vary according to the radial distance from the optical axis of the lens.

[0009] According to a second aspect of the invention, a method for manufacturing a multifocal ophthalmic lens is also provided. The method includes operating a lathe to form a surface of at least one of: a lens, a mold for the lens, or an insert for manufacturing a mold for the lens. At least a portion of the surface is formed such that it forms a power profile including a spiral. The power profile varies generally periodically radially outward from the optical axis of the lens and angularly around the optical axis of the lens. The period of the radial variation is greater than 100 micrometers, and the period of each of the angular variations is greater than 6 degrees.

[0010] According to a third aspect of the invention, a method of using the multifocal ophthalmic lens described herein is also provided. The method can effectively improve the vision of a presbyopic glasses wearer (e.g., a person aged 40 or older). Alternatively, the method can effectively reduce the progression of refractive errors, such as reducing the progression of myopia or hyperopia. When the lens of the invention is used to reduce the progression of myopia, the method includes the step of providing the ophthalmic lens to a person whose eyes are adapted. Some embodiments of the method include the step of providing the ophthalmic lens to a person aged about 5 to about 18 years. This provision can be performed by an eye care physician, such as an optician or optometrist. Alternatively, the provision can be performed by a lens distributor who arranges for the delivery of the ophthalmic lens to the lens wearer.

[0011] It will be understood, of course, that features described with respect to one aspect of the invention may be incorporated into other aspects of the invention. For example, the method of the invention may incorporate any features described with reference to the apparatus of the invention, and vice versa. Attached Figure Description

[0012] Embodiments of the invention will now be described by way of example with reference only to the accompanying schematic diagrams, wherein:

[0013] Figure 1 A contact lens according to an embodiment of the present invention is shown;

[0014] Figure 2 A power diagram showing a portion of the first surface of a contact lens according to a first embodiment of the present invention;

[0015] Figure 3 A power diagram showing a portion of the second surface of a contact lens according to a second embodiment of the present invention;

[0016] Figure 4 A diagram showing the lens power of a portion of the contact lens in the second embodiment;

[0017] Figure 5 A lens power diagram showing a portion of a contact lens according to the third embodiment; and

[0018] Figure 6A flowchart illustrating the steps of a method according to a sixth embodiment of the present invention is provided. Detailed Implementation

[0019] According to a first aspect, the present invention provides a multifocal ophthalmic lens. The surface of the ophthalmic lens varies across at least a portion of the lens to form a surface power map. Therefore, those skilled in the art will understand that the surface variation includes variations in the curvature of the lens surface. The surface power map includes a spiral having a power that varies radially outward from the optical axis of the lens in a generally periodic manner and at an angle around the optical axis of the lens. The period of the radial variation is greater than 100 micrometers, and the period of the angular variation is greater than 6 degrees.

[0020] Ophthalmic lenses may be contact lenses. The first surface may vary across the optical zone of the contact lens to form a first surface power map. Therefore, a portion of the lens may correspond to the optical zone of the lens. Alternatively, ophthalmic lenses may be artificial lenses or spectacle lenses.

[0021] In the case of contact lenses, it will be understood that the lens will include an optical zone that provides vision modification. Contact lenses according to embodiments of the invention may also include a surrounding peripheral zone that does not provide additional focusing or vision modification. In such embodiments, the peripheral zone may only be used to help hold the contact lens in position on the wearer's eye. Therefore, those skilled in the art will understand that the surface power map is defined by variations in the first surface of the optical zone across the lens. In the context of this invention, variations in the lens surface outside the optical zone (e.g., in the peripheral zone) are not considered to define the surface power map. Similar considerations also apply to artificial lenses, which may also include an optical zone and (optionally) a peripheral zone.

[0022] According to embodiments of the present invention, depending on the type of contact lens, the optical zone of the contact lens may have a diameter between 4 mm and 9 mm. For example, the diameter of the optical zone may be about 5 mm, or about 6 mm, or about 7 mm, or about 8 mm. In some embodiments, the diameter of the optical zone of the contact lens is between 7 mm and 9 mm. The optical zone includes an optical axis corresponding to the geometric center of the optical zone.

[0023] In the case of spectacle lenses, the entire lens can be used to provide vision correction, not just a part of it. Therefore, ophthalmic lenses can be spectacle lenses. The first surface may vary across the entire lens to form a first surface power map.

[0024] One or both of the radial and angular variations across the portion may be constant values.

[0025] The period of radial variation may be greater than 200 micrometers, preferably greater than 400 micrometers, and more preferably greater than 800 micrometers. The period of angular variation may be greater than 6 degrees, preferably greater than 9 degrees, more preferably greater than 18 degrees, and more preferably greater than 36 degrees.

[0026] The power may change smoothly across the portion. The power may change continuously without any discontinuities. The power may change across the portion at a rate less than 80 D / mm, preferably less than 40 D / mm, more preferably less than 20 D / mm. The surface may change smoothly across the portion. The surface may change continuously without any discontinuities. Smoothly changing the power produces a lens surface profile, which is easier to manufacture using a lathe. Those skilled in the art will understand that manufacturing ophthalmic lenses using a lathe may include using a lathe to shape the surface of one or more of the following: a lens (e.g., a contact lens), a lens mold (e.g., a contact lens mold), and an insert for the lens mold (e.g., an insert for a contact lens mold). Sharp transitions and features may be difficult to achieve using a lathe. Therefore, lenses with such features often cannot be reproduced as intended or required when manufactured using a lathe. Therefore, it will also be understood that in this context, the term "smooth" means smooth enough to allow the desired shaping of the surface of the lens, the lens mold, or the insert for the lens mold to be achieved using a lathe.

[0027] The degree can vary as a square wave in one or both of the radial and angular directions. The degree can vary as a circular square wave in one or both of the radial and angular directions. The degree can vary as a sine curve in one or both of the radial and angular directions.

[0028] Variations in degree along both the radial and angular directions may be associated with the corresponding waveform. Furthermore, the degree distribution of the waveform can be symmetrical, exhibiting a roughly equal balance between near and far vision correction. Alternatively, the degree distribution may be biased towards either far or near vision correction. Therefore, the degree distribution of the waveform can be asymmetrical in one or both of the radial and angular directions.

[0029] The period of one or both of the radial and angular variations may be substantially constant across a portion of the lens. Embodiments of the invention in which the radial and angular variations are substantially constant produce a lens surface profile that is easier to manufacture on 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 perimeter of the optical zone toward the optical axis of the optical zone.

[0030] The period of one or both of the radial and angular variations can be varied according to either or both of the radial distance from the optical axis of the lens and the angular position around the optical axis. Embodiments of the invention in which the period of one or both of the radial and angular variations varies according to their position on the lens can provide lenses in which the characteristics of the helix (e.g., its rotational speed or arm width) differ in different regions of the lens.

[0031] The change in the period of radial variation can be separated by a blending region, such as a linearly changing lens power. Therefore, the blending region can comprise concentric rings of linearly changing lens power between a first region with a first radial variation period and a second region with a second radial variation period. Thus, the blending region provides a smooth transition between regions with different periods of radial variation. Regions with different periods of radial variation may be separated by two blending regions and an intervention region with a substantially constant lens power. The blending region can have a width of approximately 25 micrometers to approximately 200 micrometers (in a plan view).

[0032] The period of angle change may be less than 180 degrees, preferably less than 90 degrees, and more preferably less than 45 degrees. The helix may include more than two arms, preferably more than four arms, and more preferably more than eight arms. Those skilled in the art will understand that the period of the sinusoidal change of the angle determines the number of arms on the helix.

[0033] The period of radial variation can be between 24 mm and 2 mm. The period of radial variation can be between 16 mm and 4 mm. Each arm of the helix may twist through between a quarter rotation and 40 rotations. Those skilled in the art will understand that the number of rotations through which the arms of the helix twist is determined by the period of radial variation and the radius (or size) of the portion of the lens. It will be understood that the radius of a reference portion (e.g., the optical zone of a contact lens) refers to a distance of half the diameter of the portion in plan view. In this context, the plan view is intended to be considered as a view along the optical axis of the lens.

[0034] 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 helix may be wider than 0.1 mm, preferably wider than 0.5 mm, and more preferably wider than 1 mm. As shown in the figures, the width of the helical arm is determined when viewing the degree diagram in a planar view (i.e., along the optical axis of the lens). Those skilled in the art will understand that the width of the arm at a given radius is defined as its vertical width (i.e., its width in the direction perpendicular to the given radius). In this context, the width of the arm is defined as the distance between two points closely adjacent to each side of the arm, the two points having a maximum or minimum gradient, between which the degree undergoes a single positive or negative offset. Those skilled in the art will understand that such a definition of width provides a linear measurement of the arm width along the tangent of a circle of a given radius. Those skilled in the art will further understand that the width measurement under this definition will differ from the measurement of the width of the arm as an arc of a circle of a given radius. Unlike the width measurement under the linear width definition, such arc-based measurements will be proportional to the angular period. The magnitude of the difference between the widths obtained by these two methods will depend on the angle period under the specific circumstances at hand.

[0035] Each arm of the spiral may extend from the center of the lens portion to the periphery of said portion. Embodiments of the invention where the arms of the spiral extend from the center of the contact lens portion to the periphery of said portion can provide a substantially constant ratio of the first lens power to the second lens power in the presence of varying pupillary dilation. Thus, such embodiments provide high-sensitivity multifocal vision under a wide range of lighting conditions.

[0036] A lens may consist of a central region and an outer region. The central region may tightly surround the optical axis of the lens. The outer region may tightly surround the central region. The power of the central region may not change periodically across the central region. The outer region may include angular and radial variations in power. Contact lenses that provide a central optical region with a lens power corresponding to distance vision and without periodic power changes ensure that the wearer maintains high acuity in distance vision even in bright conditions. For example, this may be particularly advantageous for the wearer while driving.

[0037] Contact lenses according to embodiments of the invention may include a surrounding peripheral zone that does not provide additional focusing or vision correction and is only used to help keep the contact lens in the proper position on the wearer's eye. When worn on the eye, the contact lens rests on the cornea, and the optical zone generally covers the wearer's pupil in a conventional manner. Therefore, the diameter of the central region may be less than 50% of the diameter of the optical zone, preferably less than 40%, more preferably less than 30%. The central region may be smaller than the wearer's minimum pupil size. Such embodiments of the invention provide a central region smaller than the wearer's minimum pupil size. Embodiments of the invention with a central region smaller than the wearer's minimum pupil size can maintain high acuity in near and far vision under varying light conditions.

[0038] The power of the central area can be substantially constant (e.g., the power can vary from the nominal power of the central area by less than 0.25 diopters (D)). The central area can have a lens power corresponding to distance vision. Contact lenses according to embodiments of the invention, wherein the central area has a substantially constant lens power corresponding to distance vision, provide high acuity distance vision under bright light conditions when the pupil is at its minimum size. Under bright light conditions, high acuity distance vision is generally more useful to the wearer than high acuity near vision because such conditions typically correspond to daytime outdoor environments, and the wearer generally needs more distance vision than near vision. Alternatively, the central area can have a lens power corresponding to near vision. Furthermore, the central area can have a lens power that is more corrected than the near vision correction required by the lens wearer. For example, the power of the central area may be +0.25D to +1.25D more than the near vision correction required by the eye.

[0039] The lens may include a transition region. The transition region may surround a central region. An outer region may surround the transition region. The power of the transition region may vary to provide a smooth transition between the central and outer regions. Embodiments of the invention provide a smooth transition between the central and outer regions, making it easier to manufacture using lens lathes, molds for such lenses, or inserts for such lens molds. Therefore, those skilled in the art will understand that, in this context, smoothness means that the lens profile must be smooth enough for lathe production.

[0040] 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 change periodically across a portion of the lens. Therefore, the portion as a whole may have a spiral lens power map. A contact lens according to an embodiment of the invention, wherein the optical region includes a spiral lens power map, can provide a substantially constant ratio of first lens power to second lens power in the presence of pupil size variations.

[0041] It will be understood that the second surface power map may have a power that spans a power map that is substantially constant at +0D. For the purposes of this description, the second surface of the lens is still considered to form the second surface power map, even if the second surface power map ultimately does not provide focusing or vision modification.

[0042] The degree pattern of the second surface can vary radially outward from the center of the portion in a generally periodic manner. The period of radial variation of the second surface can be greater than 100 micrometers, preferably greater than 200 micrometers, more preferably greater than 400 micrometers, and even more preferably greater than 800 micrometers.

[0043] The second surface angle diagram can vary periodically around the optical axis of the lens at an angle. The period of the angle 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.

[0044] Therefore, in some embodiments, the radial variation may have a period greater than 100 micrometers, 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 other embodiments, the radial variation may have a period greater than 200 micrometers, 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 other embodiments, the radial variation may have a period greater than 400 micrometers, 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 other embodiments, the radial variation may have a period greater than 800 micrometers, 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.

[0045] The period and phase of the radial and angular variations of the second surface can be the same as those of the first surface. Therefore, the power map of the second surface may also include a spiral, such as a spiral matching the spiral of the first surface. In such embodiments, the power map of the lens as a whole also includes a spiral. Embodiments of the invention include contact lenses with spiral lens power maps that can provide a substantially constant ratio of first lens power to second lens power in the presence of pupil size variations.

[0046] Each of the power maps formed on the first and second surfaces may include a spiral. The spirals provided by the first and second surfaces may twist in opposite directions. Therefore, the power maps of the first and second surfaces may be said to include spirals rotating in opposite directions. The spirals provided by the power maps of the first and second surfaces may be identical but twisted in opposite directions. Embodiments of the invention in which the power maps of the first and second surfaces include spirals rotating in opposite directions can provide a lens power map with an approximate dart-shaped pattern of alternating rings. Those skilled in the art will understand that the lens power map is formed by superimposing the power maps of each of the first and second surfaces. Therefore, it will also be understood that the pseudo-dartboard pattern is provided by a combination of the power maps of the first and second surfaces, each of which retains the previously described advantages of ease of manufacture. Thus, such embodiments enable the easier manufacture of lenses with pseudo-dartboard power maps using a lathe.

[0047] The lens power chart may include multiple segments. These segments may provide a first power corresponding to distance vision or a second power corresponding to near vision. Therefore, the first power may 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 may be more positive than the first power of the lens; for example, the second power may be 1D to 5D more positive than the first power. In some embodiments, the second power may be 1D to 4D more positive than the first power. In a further embodiment, the second power may be 2D to 3D more positive than the first power. Furthermore, in some embodiments, the second power may vary; for example, this may occur when the power of the discrete defocused segments is more positive than the first power, such that some 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. Variations in the second power may occur on the same arm or on different arms. These zones can be arranged on the lens so that they alternate radially and / or angularly between the first power and the second power.

[0048] Multifocal lenses can be used as myopia control lenses. Therefore, multifocal lenses can be configured to reduce myopia progression in individuals whose eyes can adequately adapt. Multifocal lenses may also be suitable for correcting presbyopia. Therefore, multifocal lenses can be configured to provide both distance and near vision correction for individuals whose eyes cannot adequately adapt (e.g., those aged 40 or older). Multiple zones can provide a power corresponding to high-sensitivity distance vision or high-sensitivity near vision. These zones can be arranged on the lens such that they alternate radially and / or angularly between high-sensitivity near and distance vision.

[0049] Contact lenses according to embodiments of the invention may include a ballast to orient the lens when placed on the wearer's eye. Such a ballast may be provided by the peripheral region of the contact lens. In some embodiments of the invention, the contact lens may provide a specific benefit to the wearer in a given direction. In embodiments of the invention incorporating a ballast into the contact lens, when placed on the wearer's eye, it will rotate to a predetermined resting angle under the action of the wearer's eyelids; for example, the ballast may be a wedge, and the rotation may be a result of the eyelids acting on the wedge. By placing the ballast in the contact lens, it is possible to ensure that the resting angle corresponds to the lens orientation that provides a specific benefit to the wearer.

[0050] According to a second aspect, the present invention provides a method for manufacturing a multifocal ophthalmic lens (e.g., a contact lens). The method includes operating a lathe to form a first surface of: a lens (e.g., a contact lens), a mold for the lens (e.g., a mold for a contact lens), or an insert for manufacturing a mold for the lens (e.g., an insert for a mold for a contact lens). The first surface is shaped to vary across at least a portion of the lens to form a first surface power map including a helix. The first surface is shaped such that the surface power map varies substantially periodically radially outward from the optical axis of the lens and angularly around the optical axis of the lens. The period of the radial variation is greater than 100 micrometers. The period of each of the angular variations is greater than 6 degrees.

[0051] The method may include operating a lathe to shape at least a portion of the surface of a lens. Alternatively or additionally, the method may include operating a lathe to shape at least a portion of the surface of a lens stacking mold. Alternatively or additionally, the method may include operating a lathe to shape at least a portion of the surface of an insert for manufacturing a lens mold. Those skilled in the art will understand that the further the object being lathe-shaped is from the lens, the fewer defined features will be reproduced on the resulting lens. Therefore, for example, using a lathe to shape the surface of a lens will achieve more defined surface features than using a lathe to shape the surface of a lens mold. The method may further include operating a lathe to shape a second surface of the lens, mold, or insert. The second surface may be shaped to vary across at least a portion of the lens to form a second surface power map including a spiral. The second surface may be shaped such that the second surface power map varies generally periodically radially outward from the optical axis of the lens and angularly around the optical axis of the lens. The period of radial variation may be greater than 100 micrometers. The period of angular variation may be greater than 6 degrees. The second surface may be shaped such that the second surface power map is a mirror image of the first surface. The second surface can be shaped such that the spiral formed by the degree map of the first surface twists in the opposite direction to the spiral formed by the degree map of the second surface.

[0052] The lens may be a contact lens. In such embodiments, a portion of the lens may correspond to the optical zone of a contact lens. In such cases, it will be understood that references to the optical zone of a mold or the insert of a mold refer to a portion of the mold that corresponds to the optical zone of a lens manufactured using said mold or insert.

[0053] Lenses (e.g., contact lenses) according to the present invention can be formed by a casting molding process, a rotary casting molding process, or a lathe process, or a combination thereof. As understood by those skilled in the art, casting molding refers to molding a lens component by placing lens forming material between a concave mold component having a concave lens component forming surface and a convex mold component having a convex lens component forming surface.

[0054] In embodiments where the ophthalmic lens includes a contact lens, the contact lens material used as part of or as the entire contact lens is visually transparent (although it may contain treatment hues). As understood in the art, contact lens materials can be hydrogel materials, silicone hydrogel materials, or silicone elastomer materials. In other words, the contact lenses of the present invention may comprise hydrogel materials, silicone hydrogel materials, or silicone elastomer materials, are substantially composed of hydrogel materials, silicone hydrogel materials, or silicone elastomer materials, or are composed of hydrogel materials, silicone hydrogel materials, or silicone elastomer materials. As understood in the art of contact lenses, a hydrogel is a material that maintains water in equilibrium and is free of silicone chemicals. A silicone hydrogel is a hydrogel containing silicone chemicals. The hydrogel materials 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 materials or silicone hydrogel materials have an EWC of about 30% to about 70% (wt / wt). In contrast, silicone elastomer materials used herein have a water content of about 0% to less than 10% (wt / wt). Typically, silicone elastomer materials used with this method or apparatus have a water content of from 0.1% to 3% (wt / wt). Alternatively, examples of the contact lenses of the present invention may be made of rigid, breathable materials, such as polymethyl methacrylate (PMMA), etc.

[0055] This method may include the step of forming a contact lens in a molded assembly comprising a first mold component and a second mold component assembled together. In the case of hydrogel or silicone hydrogel lenses, the lens can be manufactured by polymerizing a hydrogel or silicone hydrogel lens formulation containing a polymerization initiator in a lens cavity formed between the first and second mold components. For silicone elastomer lenses, the lens can be manufactured by curing, vulcanizing, or catalyzing (e.g., by hydroxylation) a liquid silicone elastomer material located in a lens cavity formed between the first and second mold components. The surface of each mold component forming the contact lens cavity can be convex, concave, planar, or a combination thereof. After the contact lens is formed, the two mold components are separated such that the contact lens remains attached to the surface of one of the mold components. As a result, a contact lens is provided on the surface of the first or second mold component. In some other embodiments, it may be desirable to place the lens component on the surface of a mold component not used to produce the first lens component, but additional steps may be required to achieve the desired alignment of the component with the mold component. The lens can then be removed from the mold component to which it is attached, and further processed, for example, by extraction and hydration, before being inspected, encapsulated, and sterilized.

[0056] Figure 1 A contact lens 10 according to an embodiment of the present invention is shown. The contact lens 10 includes an optical region 11 and a peripheral region 13. The optical region 11 includes the portion of the lens that is visible to the wearer through the lens. The optical region 11 forms a lens designed to provide vision correction to the wearer. The peripheral region 13 surrounds the optical region 11 and does not provide any vision correction to the wearer. The peripheral region 13 may perform other functions. For example, the peripheral region 13 may be used to help hold the contact lens in the wearer's eye. In some embodiments of the invention, the peripheral region 13 may include a ballast to maintain a predetermined orientation of the contact lens in the wearer's eye.

[0057] The two surfaces of the contact lens are shaped to vary across optical zone 11 to form power maps for the first and second surfaces. The power maps for the first and second surfaces are... Figure 1 This forms a lens power map. Therefore, the optical region can be said to provide a first surface power map, a second surface power map, and a lens power map. Within the optical region, the power map may include one or more different areas. Figure 1 The example contact lens shown includes 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 provide different arrangements of lens power, thus offering different vision corrections. The transition region 19 is used to provide a smooth transition between the central region 15 and the outer region 17. It will be understood that... Figure 1The contact lenses described herein are provided by way of example only, and other contact lenses according to the invention may include more or fewer areas. For example, some contact lenses according to embodiments of the invention may omit the transition area, or may even include only a single area spanning the entire optical zone 11. Other contact lenses according to embodiments of the invention may include additional areas, such as areas formed as concentric circles.

[0058] According to a first embodiment of the present invention, a multifocal contact lens is provided. It will be understood that alternative embodiments may include artificial lenses or spectacle lenses. The multifocal contact lens includes a first surface and a second surface. In this embodiment, the first surface includes the outer surface of the contact lens, and the second surface includes the inner surface of the contact lens. Those skilled in the art will understand that the outer surface is the convex surface of the contact lens adjacent to the wearer's eyelid, and the inner surface is the concave surface of the contact lens adjacent to the wearer's eye.

[0059] A portion of the first surface can be said to be shaped to form a first surface power map. In this example embodiment, said portion corresponds to the optical zone of the contact lens. Therefore, it can be said that the first surface of the optical zone forms the first surface power map. Those skilled in the art will understand that the first surface power map demonstrates a modification of the overall contact lens power map provided by the shape of said surface. Thus, a contact lens having two surfaces (an inner surface and an outer surface) will include two surface power maps, the combination of which determines the overall contact lens power map.

[0060] Figure 2A first surface power map 100 is shown, representing a portion of the first surface of the contact lens. The first surface power map 100 forms a spiral. The spiral includes a plurality of arms 101 (four in this example). Each of the arms 101 includes one of a peak arm 101a and a groove arm 101b. It will be understood that the peak arm 101a is an arm positively offset from the average power of the surface power map (or a periodically varying region of the surface power map), and the groove arm 101b is an arm negatively offset from the average power of the surface power map (or a periodically varying region of the surface power map). The spiral is formed by varying the power radially outward and at an angle around the optical axis of the contact lens, generally periodically. It will be understood 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. This example embodiment of the multifocal contact lens has a base lens power of -3.0D and an additional power of +3.0D. Therefore, the first lens power is -3.0D, and the second lens power is +0D. This type of contact lens may be suitable for patients with both myopia and presbyopia. The -3.0D base lens power is used to correct the wearer's distance vision, while the +3.0D additional power is used to correct the wearer's near vision when the wearer cannot adequately adapt. Those skilled in the art will understand that the specific values ​​of the first and second lens powers (and thus the base and additional power) provided are merely examples, and the actual values ​​used in a given situation will be determined by the intended wearer's needs.

[0061] In this example embodiment, the radial variation period is 1.2 mm, and the angular variation period is 90 degrees. However, it will be understood that in alternative embodiments, other periods of radial and / or angular variation may be used. The radial variation period only needs to be greater than 100 micrometers, and the angular variation period only needs to be greater than 6 degrees.

[0062] In this particular embodiment, the power varies smoothly across the first surface power pattern 100, generally following a sinusoidal curve in both the radial and angular directions. This partial smoothing of the surface power pattern across the lens facilitates manufacturing using a contact lens lathe or equipment for manufacturing contact lenses (e.g., a mold or mold insert). However, in alternative embodiments, the power may vary according to other waveforms. For example, the power may vary in the form of a square wave or a circular square wave in one or both of the radial and angular directions. Therefore, in alternative embodiments, the power need not vary partially across the lens.

[0063] In this example embodiment, the positive and negative offset lengths of the sine curve are equal, such that the sine curve can be said to have a 50% duty cycle. Alternative embodiments include variations with other duty cycles. Thus, in such embodiments, the positive offset may be a different length than the negative offset.

[0064] It will be understood that the width of the arms 101 of the helix 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 arm 101 of the helix is ​​approximately 500 micrometers wide. It will be understood that alternative embodiments may combine arms 101 with different widths. It will also be understood that the width of the arm 101 is defined as its vertical width.

[0065] Similarly, in this example embodiment, the period of each of the radial and angular variations is substantially constant across the portion. However, in an alternative embodiment, the period of at least one of the radial and angular variations may be varied based on one or both of the radial distance from the center of the portion and the angular position around the center of the portion.

[0066] In an alternative embodiment, the period of angle change is less than 180°. Those skilled in the art will understand that the period of angle change determines the number of arms 101 on the helix. Therefore, in such embodiments, the helix comprises at least two arms. It will also be understood that certain values ​​of angle change, particularly those fractions of 360 degrees, may be particularly advantageous because they allow for a surface degree map without angular discontinuities.

[0067] In this exemplary embodiment, each arm 101 of the helix twists through an angle of 270 degrees (or a rotation of 0.75). In an alternative embodiment of the invention, each arm 101 of the helix may twist between a quarter rotation (90 degrees) and a 40-degree rotation.

[0068] In this particular embodiment, the first surface power map 100 includes a central region 103 and an outer region 105. The central region 103 closely surrounds the optical axis of the contact lens. The outer region 105 surrounds the central region 103. The power of the central region does not change periodically across the central region 103, and for example, the power of the central region may be substantially constant across the central region 103. The outer region 105 includes a helical power map, and therefore includes angular and radial variations in the power.

[0069] In an alternative embodiment of the invention, each arm 101 of the spiral extends from the center of the portion of the lens to the periphery of the portion. Therefore, such embodiments do not include distinct central and outer regions.

[0070] As previously mentioned, in this example embodiment, a portion of the lens corresponds to the optical zone of the contact lens. In this example 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 wearer receives [viewing information] through the optical zone. Figure 2The first surface power diagram is shown in the figure. The contact lens may additionally include a surrounding peripheral region that does not provide additional focusing or vision correction, but only helps maintain the proper position of the contact lens on the wearer's eye. The diameter of the central region may be less than 25% of the diameter of the optical region. However, it will be understood that in alternative embodiments of the invention, the diameter of the central region 103 may take other values. Similarly, it will be understood that the ratio of the diameter of the central region 103 to the diameter of the optical region may also take other values. For example, the diameter of the central region 103 may be less than 30% of the diameter of the optical region.

[0071] In this embodiment, the central region 103 may be smaller than the wearer's minimum pupil size. This embodiment maintains multifocal vision even when the wearer's pupil constricts to its minimum size. If the central region 103 is larger than the minimum pupil size, then only the central region 103 will position across the wearer's entrance pupil when the wearer's pupil constricts to its minimum size. Because the power of the central region 103 does not change with the spiral across the central region 103, the lens element will not provide multifocal vision for any pupil size smaller than the central region 103.

[0072] Advantageously, in this example embodiment, the central region 103 provides a lens power corresponding to distance vision. Typically, brighter conditions correspond to outdoor environments. Therefore, the wearer's pupils generally constrict more outdoors than indoors. Additionally, the wearer typically needs distance vision more outdoors than indoors. Even when the wearer's pupils are constricted to their minimum size, the central region 103, with its lens power corresponding to distance vision, allows the contact lens to provide high-sensitivity distance vision.

[0073] This example embodiment further includes a transition region 107. The transition region 107 surrounds the central region 103. An outer region 105 surrounds the transition region 107. The degree variation of the transition region 107 provides a smooth transition between the central region 103 and the outer region 105. It will be understood that such a transition region 107 is not necessary, and therefore alternative embodiments do not include a transition region 107. It will be understood that, in this context, smoothness is defined as smooth enough that the corresponding lens curvature can be reproduced by lathe work. In this example embodiment, the transition region is approximately 300 micrometers wide. However, it will be understood that transition regions of other widths may also be used.

[0074] Those skilled in the art will understand that the second surface of a portion of the contact lens (i.e., the second surface of the optical zone of the contact lens in this example embodiment) forms a second surface power map. In this example embodiment, the second surface power map does not change periodically across the portion. Therefore, the contact lens has a spiral lens power map. Thus, as the wearer's pupil changes size, the contact lens provides a reduced near-focus to far-focus ratio.

[0075] While in this exemplary embodiment, the first surface corresponds to the outer surface of the contact lens and the second surface corresponds to the inner surface, those skilled in the art will understand that in alternative embodiments, the first surface may correspond to the inner surface and the second surface may correspond to the outer surface. Thus, in this embodiment, the inner surface includes a surface degree map forming a spiral, and the outer surface includes a generally flat surface degree map.

[0076] According to a second embodiment of the present invention, a second multifocal contact lens is provided. The first surface of the second contact lens is the same as the first surface of the contact lens of the first embodiment.

[0077] In this embodiment, the second surface degree diagram 200 ( Figure 3 The second surface degree map 200 also varies periodically around the center of the portion at an angle and radially outward from the center of the portion. Therefore, the second surface degree map 200 also includes a spiral. Similar to the first surface, the spiral includes a plurality of arms 201 comprising peak arms 201a and groove arms 201b. In this exemplary embodiment, the periods of radial and angular variation of the second surface degree map 200 are the same as those of the first surface degree map 100. However, those skilled in the art will appreciate that alternative embodiments may incorporate variations with different periods on the second surface degree map 200 into one or both of those of the first surface degree map 100. Again, in an alternative embodiment, the period of angular variation of the second surface degree map 200 is greater than 6 degrees. Similarly, in an alternative embodiment, the period of radial variation of the second surface degree map 200 may be greater than 100 micrometers. In this exemplary embodiment, the second surface degree map 200 also includes a central region 203, an outer region 205, and a transition region 207.

[0078] In this example embodiment, the spiral formed by the second surface degree diagram 200 and the spiral formed by the second surface degree diagram 200 are... Figure 2 The spiral formed by the first surface power map 100 twists in opposite directions. Therefore, in this particular embodiment, the spirals provided by the first surface power map 100 and the second surface power map 200 are the same, but twist in opposite directions. The power map of the contact lens is determined by superimposing the power maps of the first surface power map 100 and the second surface power map 200. Figure 4 A diagram showing the prescription of the contact lens according to the second embodiment is displayed.

[0079] The superposition of two counter-rotating spirals formed by the first surface power map 100 and the second surface power map 200 produces a lens power map that approximates a pseudo-dartboard pattern of alternating rings. The lens power alternates approximately between the first and second lens powers in both the radial and angular directions. Because the power alternates angularly between the first and second lens powers, the contact lens also provides a monotonic change in the ratio of the first to the second lens power as the wearer's pupil constricts. Therefore, the contact lens 300 can also provide improved multifocal vision in the presence of variable light conditions.

[0080] Since both the first surface power map 100 and the second surface power map 200 include a center, a periphery, and a transition region, the overall power map of the contact lens 300 also includes a central region 303, an outer region 305, and a transition region 307.

[0081] Figure 5 A contact lens according to a third embodiment of the present invention is shown. The third embodiment is substantially the same as the second embodiment, but the spiral provided by the second surface degree diagram has been rotated by 45 degrees and phase-shifted. (See from...) Figure 5 As can be seen, the superposition of the first and second surface power maps, including two counter-rotating spirals, produces a pseudo-dartboard power map similar to that of the second embodiment. Therefore, regardless of the relative phase of the first and second spirals, the superposition of the two counter-rotating spirals will produce a pseudo-dartboard lens power map.

[0082] Furthermore, the overall power profile of the contact lens 400 includes a central region 403, an outer region 405, and a transition region 407. According to a fourth embodiment of the invention, a spectacle lens is provided. The spectacle lens includes a spiral power profile generally as described with respect to the first embodiment of the invention. However, those skilled in the art will understand that the spectacle lens does not include an optical zone in the same sense as the contact lens of the first embodiment. Therefore, in this case, a portion of the lens does not correspond to an optical zone. Those skilled in the art will further understand that the characteristics of the lens profile associated with the optical zone of the contact lens as defined above also apply to portions of the spectacle lens of this embodiment. It will be understood that alternative embodiments of the invention include spectacle lenses having a surface power profile generally as described with respect to the second and third embodiments of the invention.

[0083] According to a fifth embodiment of the present invention, an artificial lens is provided. The artificial lens includes a helix generally as described with respect to a first embodiment of the invention. It will be understood that alternative embodiments of the invention include artificial lenses having a surface power map generally as described with respect to second and third embodiments of the invention.

[0084] Figure 6A flowchart illustrating the steps of a method 500 for manufacturing a lens (e.g., a contact lens) according to a sixth embodiment of the present invention is shown.

[0085] The first step of method 500, represented by element 501, includes operating a lathe to form a first surface of: a lens, a mold for the lens, or an insert for manufacturing a mold for the lens. The first surface is formed such that it varies across at least a portion of the lens (e.g., the optical zone of a contact lens) to form a first surface power pattern. The first surface power pattern includes a spiral and varies radially outward and angularly around the optical axis of the contact lens, generally periodically. The period of the radial variation is greater than 100 micrometers. The period of the angular variation is greater than 6 degrees.

[0086] An optional second step of method 500, represented by element 503, includes operating a lathe to form a second surface of the lens, a lens mold, or an insert for manufacturing a lens mold. The second surface is formed such that it varies across at least a portion of the lens to form a second surface power pattern. The second surface power pattern includes a spiral and varies generally periodically radially outward from the optical axis of the contact lens and angularly around the optical axis of the contact lens. The period of the radial variation is greater than 100 micrometers. The period of each of the angular variations is greater than 6 degrees.

[0087] The second surface can be shaped to become a mirror image of the first surface. Alternatively, the second surface can be shaped such that the spiral formed on the first surface is twisted in the opposite direction to the spiral formed on the second surface.

[0088] When the first surface (and the second surface in which the second step 503 has been performed) is included on a mold for a lens or an insert for a mold for a lens, method 500 may include an optional third step represented by element 505. The third step 505 includes manufacturing a lens using a mold with an insert for a mold for a lens.

[0089] Although the invention has been described and illustrated with reference to specific embodiments, those skilled in the art will understand that the invention is applicable to many different variations not specifically described herein. Some possible variations will now be described by way of example only.

[0090] In a first embodiment, the lens with a spiral lens power map is provided by a first surface power map including a spiral and a second surface power map having a substantially constant power. However, in an alternative embodiment, the lens with a spiral lens power map is provided by each of the first and second surface power maps including a spiral. In such embodiments, 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. Therefore, the first and second surface power maps can be said to be mirror images of each other. Thus, the first and second surface power maps are superimposed to form a single spiral power map, thereby forming a contact lens with a spiral lens power map.

[0091] In all the first, second, and third embodiments, each of the contact lens surface power maps includes a central region with a substantially constant power, an outer region that incorporates the spiral power profile, and a transition region that provides a smooth transition between the central and outer regions. However, some alternative embodiments do not incorporate the transition region. Further alternative embodiments do not incorporate the distinct central and outer regions. Instead, in such embodiments, the spiral profile extends from the center of a portion of the lens to the radial periphery of said portion.

[0092] In a first embodiment, the spiral formed by the first surface degree map twists counterclockwise. However, in an alternative embodiment, the spiral formed by the first surface degree map twists clockwise. In those embodiments where mirrored spirals are formed on the first and second surface degree maps, the spiral can rotate in either clockwise or counterclockwise directions. Similarly, in a second embodiment, the spiral formed on the first surface degree map twists counterclockwise, and the spiral formed on the second surface degree map twists clockwise. However, in an alternative embodiment, the spiral formed on the first surface degree map twists clockwise, and the spiral formed on the second surface degree map twists counterclockwise.

[0093] In some embodiments of the invention, a helix formed on one or both of the first and second surface power diagrams changes its direction of rotation at a predetermined radial distance from the center of the portion. For example, the helix may rotate clockwise between the center of the portion and the predetermined radial distance, and may rotate counterclockwise beyond the predetermined radial distance. In some embodiments, the lens incorporates more than one change in the direction of rotation of the helix. Thus, for example, the helix may change from clockwise rotation to counterclockwise rotation and then back to clockwise rotation. Those skilled in the art will understand that the lens can incorporate any number of changes in the direction of rotation of the helix. It will also be understood that each of the changes in direction can occur at any selected radial distance from the center of the portion. Thus, the power diagram may include annular loops alternating between clockwise and counterclockwise rotating helices.

[0094] In some embodiments, between regions of ophthalmic lenses with different rotational directions, there exist regions where the power map does not exhibit a spiral variation. For example, such regions may have a substantially constant power. For instance, from the center of the portion to a first radial distance, the lens (or surface) power map may exhibit a clockwise spiral variation, followed by a region of substantially constant power, and then a counterclockwise spiral variation. Thus, the power map can be viewed as comprising multiple rings, for example, alternating between spirals and substantially constant power, wherein spiral regions also alternate between clockwise and counterclockwise rotations.

[0095] Similarly, in some embodiments, the spiral may be interrupted by one or more regions (e.g., loops) where the diopter diagram does not change as the spiral changes. For example, the regions may have a substantially constant diopter. Thus, for example, the diopter diagram may include interlocking loops alternating between spiral diopters and substantially constant diopters. In such embodiments, the spiral may change its direction of rotation between each interruption, or it may continue its previous direction of rotation. Thus, the spiral may maintain a constant direction of rotation across the lens, but may be interrupted by regions with substantially constant lens diopters.

[0096] While embodiments of the invention have been described above with respect to methods for manufacturing contact lenses, molds for contact lenses, or inserts for molds for contact lenses using a lathe, it will be understood that other manufacturing methods are also possible. Specifically, the molds or inserts may also be manufactured using additive manufacturing techniques, such as 3D printing.

[0097] In the foregoing description, references are made to integers or elements having known, obvious, or foreseeable equivalents, and such equivalents are then incorporated herein as if individually stated. Reference should be made to the claims to determine the true scope of the invention, which should be interpreted as covering any such equivalents. The reader will also understand that integers or features of the invention described as preferred, advantageous, convenient, or similar are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that while such optional integers or features may be beneficial in some embodiments of the invention, they may not be desired in other embodiments and therefore may not be present.

Claims

1. A multifocal ophthalmic lens, wherein: a first surface of the lens varies across at least a portion of the lens to form a first surface power map; the first surface power map comprises a spiral having a power that varies substantially periodically radially outward from and angularly around an optical axis of the lens; a period of the radial variation is greater than 100 microns; and a period of the angular variation is a fractional portion of 360 degrees.

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

3. The multifocal ophthalmic lens of claim 1 or 2, wherein the power varies smoothly across the portion.

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

5. The multifocal ophthalmic lens of claim 1 or 2, wherein the power varies radially and angularly as a square wave.

6. The multifocal ophthalmic lens of claim 1 or 2, wherein the period of the radial and angular variations each is substantially constant across the portion.

7. The multifocal ophthalmic lens of claim 1 or 2, wherein the period of at least one of the radial and angular variations varies as a function of one or both of: a radial distance from the optical axis of the lens and an angular position around the optical axis of the lens.

8. The multifocal ophthalmic lens of claim 1 or 2, wherein: the lens comprises a central region closely surrounding the optical axis of the lens and an outer region surrounding the central region; a power of the central region varies no periodically across the central region; and the outer region comprises the angular and radial variations of power.

9. The multifocal ophthalmic lens of claim 8, wherein the central region has a diameter that is less than 50% of a diameter of the portion.

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

11. The multifocal ophthalmic lens of claim 1 or 2, wherein: the lens comprises 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 a power that varies substantially periodically radially outward from and angularly around the optical axis of the lens; a period of the radial variation of the second surface power map is greater than 100 microns; and a period of the angular variation of the second surface power map is a fractional portion of 360 degrees.

12. The multifocal ophthalmic lens of claim 11, wherein: the first surface power map and the second surface power map each comprise a spiral; and the power of the spiral of the first surface power map and the second surface power map each varies radially and angularly. The helix provided by the first and second surface power maps twists in opposite directions.

13. The multifocal ophthalmic lens of claim 1 or 2, wherein the multifocal ophthalmic lens is a myopia control lens.

14. A method of manufacturing a multifocal ophthalmic lens, the method comprising: operating a lathe to shape a first surface of at least one of: a lens, a mold of a lens, or an insert for a mold used to manufacture a lens, such that: 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 helix; the first surface power map varies generally periodically radially outward from and angularly around an optical axis of the lens; a period of the radial variation is greater than 100 microns; and a period of the angular variation is a fractional number of 360 degrees.

15. The method of claim 14, further comprising operating the lathe to shape a second surface of the lens, the mold, or the insert, such that: the second surface varies across the portion of the lens to form a second surface power map; the second surface power map comprises a helix; the second surface power map varies generally periodically radially outward from and angularly around an optical axis of the lens; the period of the radial variation is greater than 100 microns; and the period of the angular variation is a fractional number of 360 degrees.

16. A method of improving vision in a person, the method comprising: providing a multifocal ophthalmic lens to a person in need of improved vision, wherein a first surface of the lens varies across at least a portion of the lens to form a first surface power map; the first surface power map comprises a helix having a power that varies generally periodically radially outward from and angularly around an optical axis of the lens; a period of the radial variation is greater than 100 microns; and a period of the angular variation is a fractional number of 360 degrees.

Images