Intraocular lens with zone-by-zone step height control - Patents.com

Abstract

To provide intraocular lenses having a zone by zone step height control.SOLUTION: A method and a system provide an ophthalmic device. The ophthalmic device includes an ophthalmic lens having anterior surface, a posterior surface and at least one diffractive structure including a plurality of zones. The at least one diffractive structure is for at least one of the anterior surface and the posterior surface. Each zone includes at least one echelette having one or more step heights. The step heights are individually optimized for each zone. To compensate chromatic aberration of an eye from a distance to a range of vision, a phase step height greater than the 2π phase step height may be employed and folded by a phase which is an integer multiple of 2π. Hence, the chromatic aberration of an eye may be compensated to improve vision from the distance vision to the near vision.SELECTED DRAWING: Figure 1A-1B

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to intraocular lenses, and more particularly to intraocular lenses having zones with zonal step height control.

[0002] Intraocular lenses (IOLs) are implanted in a patient's eye either to replace or to supplement the patient's crystalline lens. IOLs may be implanted in place of the patient's crystalline lens during cataract surgery. Alternatively, IOLs may be implanted in a patient's eye to enhance the refractive power of the patient's own crystalline lens.

[0003] Some conventional IOLs are single focal length IOLs, while others are multifocal IOLs. Single focal length IOLs have a single focal length or power. Objects at the focal length from the eye / IOL are in focus, while closer or more distant objects may not be in focus. Although objects are only fully in focus at the focal length, objects within the focal depth (within a certain distance of the focal length) are still in focus to the extent that the patient may consider the objects to be in focus. Multifocal IOLs have at least two focal lengths. For example, bifocal IOLs have two focal lengths (i.e., a far focus corresponding to a long focal length and a near focus corresponding to a short focal length) to improve focus in two regions. In this way, the patient's far and near vision can be improved. Conventional diffractive bifocal IOLs usually use the 0th diffraction order for far focus / distance vision and the 1st diffraction order for near focus / near vision. A trifocal IOL has three foci (i.e., a far focus for far vision, a near focus for near vision, and an intermediate focus for intermediate vision with an intermediate focal length between the focal lengths of the near focus and the far focus). Conventional diffractive trifocal IOLs usually use a zeroth diffraction order for far vision, a first diffraction order for intermediate vision, and a second diffraction order for near vision. A multifocal IOL may improve a patient's ability to focus on distant objects and nearby objects. In other words, a patient's depth of focus may be enhanced. A trifocal IOL has three foci (i.e., a far focus for far vision, a near focus for near vision, and an intermediate focus for intermediate vision). The intermediate focus has an intermediate focal length between the focal lengths of the near focus and the far focus. A multifocal IOL may improve a patient's ability to focus on distant objects and nearby objects.

[0004] To fabricate a conventional IOL, optical design software is typically employed. The desired focal length and locations of the zones on the lens surface are provided. Given these inputs, the entire lens is analytically optimized using optical software. In other words, the diffractive structure of multiple zones is simultaneously optimized using analytical tools. As a result, an IOL can be provided.

[0005] Although useful in addressing optical conditions, IOLs may suffer from various shortcomings, such as longitudinal chromatic aberration and / or limited depth of focus. Different colors of light have different wavelengths and therefore different frequencies. As a result, the IOL focuses different colors of light at different distances from the crystalline lens. The IOL may not be able to focus different colors of light onto the patient's retina. The polychromatic image contrast of the IOL may be adversely affected. In addition, the depth of focus of the IOL may not be as large as desired. The patient's vision at the further range of focal length may be adversely affected. Finally, an extended depth of focus (EDOF) may be desirable.

[0006] Therefore, what is needed is a system and method for improving IOLs. Summary of the Invention [Means for solving the problem]

[0007] The method and system provide an ophthalmic device. The ophthalmic device includes an ophthalmic lens having an anterior surface, a posterior surface, and at least one diffractive structure including a plurality of zones. The at least one diffractive structure is for at least one of the anterior and posterior surfaces. Each zone includes at least one echelette having at least one step height. The step heights are provided individually for each zone. The at least one step height is also folded by a phase that is an integer multiple of 2π.

[0008] The lens may have the diffractive structures described above and may have reduced chromatic aberration and a larger EDOF, which may result in improved performance.

[0009] For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which like reference characters indicate like features, and in which: [Brief description of the drawings]

[0010] [Figure 1A-1B]1 depicts top and side views of an exemplary embodiment of a multifocal ophthalmic device including individually optimized zones and phase wrapping. [Diagram 2] 1 depicts an exemplary embodiment of a sag profile of a diffractive structure of a multifocal ophthalmic lens including individually optimized zones and phase wrapping. [Figure 3A-3B] 1 depicts an exemplary embodiment of intensity versus focus shift for a multifocal ophthalmic lens including individually optimized zones and phase wrapping. [Figure 4] 1 depicts an exemplary embodiment of a sag profile of a diffractive structure of an ophthalmic lens having an extended depth of focus and including individually optimized zones and phase wrapping. [Figure 5A-5B] 1 depicts an exemplary embodiment of intensity versus focus shift for a lens with individually optimized zones and phase wrapping. [Figure 6] 1 is a flowchart depicting an exemplary embodiment of a method for fabricating an ophthalmic device including individually optimized zones and phase wrapping. [Figure 7] 1 depicts an exemplary embodiment of a sag profile for a diffractive structure under design that includes individually optimized zones. [Figure 8] 1 depicts an exemplary embodiment of a sag profile of a diffractive structure being designed that includes individually optimized zones and phase wrapping. [Figure 9] 1 is a flowchart depicting an exemplary embodiment of a method of utilizing an ophthalmic device including a multifocal lens that may have reduced chromatic aberration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Exemplary embodiments relate to ophthalmic devices such as IOLs and contact lenses. The following description is presented to enable one skilled in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the exemplary embodiments and the general principles and features described herein will be readily apparent. The exemplary embodiments will be described primarily in terms of specific methods and systems provided in specific embodiments. However, the methods and systems will operate effectively in other embodiments. For example, the methods and systems will be described primarily in terms of IOLs. However, the methods and systems may be used with contact lenses. Phrases such as "exemplary embodiment," "one embodiment," and "another embodiment" may refer to multiple embodiments as well as the same or different embodiments. The present embodiments will be described in terms of a system and / or device having several components. However, the systems and / or devices may include more or fewer components than shown, and variations in the arrangement and type of components may be made without departing from the scope of the invention. The exemplary embodiments will also be described in terms of a specific method having several steps. However, the method and system can be effectively operated with other methods having different and / or additional steps, and steps in a different order not inconsistent with the exemplary embodiments. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein.

[0012] The method and system provide an ophthalmic device. The ophthalmic device includes an ophthalmic lens having an anterior surface, a posterior surface, and at least one diffractive structure including a plurality of zones. The diffractive structure is for at least one of the anterior and posterior surfaces. Each zone includes at least one echelette having at least one step height. The step heights are determined individually for each zone. The step heights are also folded by a phase that is an integer multiple of 2π.

[0013] 1A-1B depict an exemplary embodiment of an ophthalmic device 100 that may be used as an IOL. FIG. 1A depicts a top view of the ophthalmic device 100, while FIG. 1B depicts a side view of an ophthalmic lens 110. For clarity, FIGS. 1A, 1B are not to scale, are for illustrative purposes only, and only some features are shown. The ophthalmic device 100 includes an ophthalmic lens 110 (hereinafter "lens") and haptics 102, 104. The lens 110 may be made of a variety of optical materials, including, but not limited to, one or more of silicone, hydrogel, acrylic, AcrySof®. The haptics 102, 104 are used to hold the ophthalmic device 100 in place within a patient's eye (not shown). In other embodiments, other mechanisms may be used to hold the ophthalmic device in the proper position within the eye. Thus, the haptics 102 and / or 104 may be omitted. For clarity, the haptics are not depicted in the remaining accompanying figures. Although the lens 110 is depicted in the plan view of FIG. 1A as having a circular cross-section, other shapes may be used in other embodiments. Although described in connection with an IOL, the lens 110 may be a contact lens. In such a case, the haptics 102 would be omitted and the lens 110 would be sized and otherwise configured to remain on the surface of the eye.

[0014] The lens 110 may be, but need not be, a multifocal lens. The lens 110 has an anterior surface 112, a posterior surface 114, and an optical axis 116. The lens is also characterized by a diffractive structure 120 and a base curve 121. The lens 110 may provide a base power, astigmatism correction, and / or other vision correction. The lens 110 may be aspheric and / or toric, have the same or different base curves on the surfaces 112, 114, and / or other features not shown or discussed in detail for simplicity. Although one diffractive structure 120 is shown on the anterior surface 112, a diffractive structure 120 could be disposed on the posterior surface 114. In yet other embodiments, a diffractive structure could be disposed on the anterior surface 112 and the posterior surface 114. Such diffractive structures may be the same or different. The diffractive structure 120 may be, but need not be, a partial aperture diffractive structure. Additionally, although shown as a physical diffractive structure, in other embodiments, the diffractive structure 120 could be formed by modification of the refractive index of the lens 110.

[0015] The diffractive structure 120 may provide a single focal length or multiple focal lengths. In some embodiments, the diffractive structure 120 is used to provide a bifocal (two focal lengths for near and far vision) lens 110. In other embodiments, the diffractive structure 120 may provide a trifocal (three focal lengths for near, intermediate and far vision) lens 110. Quadrafocal or other multifocal lenses may also be provided. The diffractive structure 120 may be configured for a specific wavelength. For example, different zones 111 of the diffractive structure 120 may be configured for different wavelengths of light. Alternatively, the diffractive structure 120 may be designed for a single wavelength of light.

[0016] The diffractive structure 120 includes multiple zones 122A, 122B, 122C (collectively zones 122) corresponding to different ranges (i.e., different radii) in distance perpendicular to the optical axis 116. Although three zones 122 are shown, the lens 110 may have another number of zones. The zones 122A, 122B, and / or 122C are circles or annular rings along the surface from a minimum radius to a maximum radius from the optical axis 116. For example, in some embodiments, the diffractive structure 120 may have a ring diameter of the zones 122 set by a Fresnel diffractive lens criterion. Alternatively, other criteria may be used to determine the size and location of each zone of the zones 122.

[0017] Each of the zones 122 includes a step or echelette 124. The echelette 124 has a step height that corresponds to a phase difference. The step height of the echelette 124 is the physical step height (h) multiplied by the difference in refractive index between the lens 110 and the surrounding medium (Δn). In other words, step height = h·Δn. The phase difference φ of the echelette 124 is proportional to the step height divided by the wavelength λ. More specifically, φ = (2·π·h·Δn) / λ. Thus, a phase difference of 2π corresponds to one wavelength in step height. Thus, the terms step height and phase are considered to be effectively synonymous herein.

[0018] The echelettes 124 in one or more of the zones 122 are individually optimized. Stated another way, one or more characteristics of the echelettes 124 in a zone 122A, 122B, and / or 122C are determined for that zone 122A, 122B, and / or 122C, respectively, independent of the characteristics of the echelettes 124 in the other zones. In some embodiments, the step height (phase) of the echelettes 124 in the zones 122 is determined separately on a zone-by-zone basis. Thus, the step height of each zone 122A, 122B, and / or 122C is determined independently of the step height of the other zones. In other embodiments, the addition or other characteristics of the echelettes 124 may be configured separately on a zone-by-zone basis. For example, the spacing between the echelettes 124 may also be controlled independently for each zone 122.

[0019] The characteristics of the echelettes 124 for each of the zones 122A, 122B, 122C may be independently optimized based on selected criteria. For example, the particular focal length of the lens 110, the target focal position, the location and amount of constructive interference, the target phase, and / or other criteria may be used to determine the step height for each zone 122 separately. These criteria may vary between the zones 122. In other embodiments, these criteria may be the same for each zone 122. Because the locations of the zones 122 differ from one another, different step heights may be determined for the different zones 122 even though the criteria remain the same.

[0020] In some embodiments, the phase (i.e., step height) of the echelettes 124 within each zone may be individually optimized such that each of the zones 122 actively interferes at various target locations. As a result, the depth of focus of the lens 110 may be improved. In some examples, a relatively uniform through focus may be achieved. Each of the zones 122 may be separately optimized with respect to one or more of the focal lengths of the multifocal lens 110. For example, each of the zones 122 may be optimized to provide various intermediate focal lengths. Thus, the depth of focus may be improved.

[0021] Although discussed with reference to independently configuring the echelettes 124 for each zone 122, one skilled in the art will recognize that not all of the zones 122 must be so configured. For example, in some embodiments, the echelettes 124 for only zones 122A, 122B may be determined separately. In other embodiments, the echelettes 124 for only zones 122A, 122C may be configured separately. In still other embodiments, the characteristics of the echelettes 124 for only zones 122B, 122C may be determined independently. In other embodiments, all of the zones 122 of the lens 110 may be manipulated independently. Thus, the particular zones 122 having echelettes 124 that are independently manipulated may vary between embodiments.

[0022] Zones 122 may be subject to phase wrapping in addition to separate zone-by-zone optimization of step height. The individually determined step heights of one or more of zones 122 may be large. The corresponding phases may exceed 2·π. In some cases, the optimized step heights may correspond to phases of at least 3·π, 4·π, or more. Thus, if the step heights are large enough, the step heights are wrapped by a phase of 2·π·n, where n is a positive integer. In some embodiments, the step heights of the echelettes 124 may be reduced to provide a maximum phase of 2·π. Thus, in addition to being separately controlled, the step heights of the echelettes 124 of each zone 122A, 122B, and / or 122C are folded. This reduction in step heights may reduce optical interference from light far from the optical axis 116. Phase wrapping may also provide negative dispersion that may partially or fully compensate for the positive dispersion of the material from which lens 110 is formed.

[0023] The ophthalmic lens 110 may have improved performance. The ophthalmic lens 110 may be a multifocal lens. The ophthalmic device 100 may be used to treat conditions such as presbyopia. Other conditions such as astigmatism may be treated. The performance of the lens 110 may be improved through the use of the base curve 121, the aspheric surface of the lens 110, the torus of the lens 110, the apodization of the echelettes 122, and other features of the lens. In addition, the lens 110 may have improved EDOF as well as reduced chromatic aberration. Separate control of the step height of the echelettes 124 in each zone 122 may allow the image to be well focused over a larger range of distances. Thus, the depth of focus may be improved. Since the echelettes are also phase folded, the chromatic aberration introduced by the lens 110 may be compensated. This use of superzones and phase wrapping may compensate for the chromatic aberration of the eye due to the strong negative dispersion of the diffractive lens, correcting the chromatic aberration from far to some field of vision. Thus, the depth of focus can be increased while a more achromatic lens 110 can be provided, ultimately improving performance.

[0024] The advantages of the ophthalmic lens 110 may be better understood with respect to some embodiments. FIG. 2 depicts a sag profile 130 of another exemplary embodiment of a diffractive structure including individually controlled zones and phase wrapping. Thus, the sag profile 130 and the diffractive structure 130 are referred to interchangeably. The diffractive structure 130 may replace the diffractive structure 120 in the lens 110. The sag profile 130 shows that there are zones 134, 136, 138, each including one or more echelettes 132. FIGS. 3A and 3B are graphs 140, 150, respectively, depicting an exemplary embodiment of monochromatic and photopic intensity versus focus shift for a trifocal lens 110 made with the diffractive structure 130. Curves 142, 152 are for one set of line pairs, while curves 144, 154 are for another set of line pairs with doubled frequency. FIGS. 2-3B are not to scale and are for illustrative purposes only.

[0025] As can be seen from the graphs 140, 150, the through-focus modulation transfer function (MTF) curves 142 / 152 and 144 / 154 are shifted thanks to the separate zone-by-zone control of the step height of the echelettes 132 in the sag profile 130. This shift compensates for the valleys in the MTF curves. Thus, the depth of focus of the lens incorporating the sag profile 130 has been improved. Due to the phase wrapping of the diffractive structure 130, chromatic aberration may also be compensated. As a result, the MTF is shown to degrade by a small amount over the entire extended distance in the graphs 140, 150. Thus, the depth of focus and chromatic aberration correction of the lens 110 with the sag profile 130 may be improved. The performance of the lens 110 employing the diffractive structure with the sag profile 130 may be enhanced.

[0026] FIG. 4 depicts a sag profile 130' of another exemplary embodiment of a diffraction including individually controlled zones and phase wrapping. Thus, the sag profile 130' and the diffractive structure 130' are referred to interchangeably. The diffractive structure 130' can replace the diffractive structure 120 in the lens 110. The sag profile 130' illustrates that there are zones 134', 136', 138' each including one or more echelettes 132'. FIGS. 5A and 5B are graphs 140', 150', respectively, depicting an exemplary embodiment of MTF versus focus shift for a trifocal lens 110 created with the diffractive structure 130'. Curve 142' depicts the monochromatic MTF, while curve 152' is the photopic MTF. FIGS. 4-5B are not to scale and are for illustrative purposes only. In the illustrated embodiment, the near power may be set by adding power to the lens 110, while the intermediate power may be provided by a separate zone-by-zone optimization of the step height of the sag profile 130'. In addition, the step height of the echelettes 132' may be folded back by an integer multiple of 2·π. For example, the maximum phase corresponding to the echelettes 132' may be 2·π.

[0027] As can be seen from graphs 140', 150', curves 142', 152' provide intermediate focus. This is due to separate control of the echelette step heights of zones 134', 136', 138' as shown in sag profile 130'. Thus, the depth of focus has been improved. Because of the phase wrapping of diffractive structure 130', chromatic aberration may also be compensated and the depth of focus and chromatic aberration correction of lens 110 having sag profile 130' may be improved. Thus, the performance of lens 110 employing diffractive structure having sag profile 130 may be enhanced.

[0028] FIG. 6 is an exemplary embodiment of a method 200 for providing a multifocal diffractive lens with reduced chromatic aberration. For simplicity, some steps may be omitted, interleaved, and / or combined. FIGS. 7, 8 depict sag profiles 170, 170' of lenses designed using the method 200. The sag profiles 170, 170' are for illustrative purposes only and are not intended to represent a specific device. With reference to FIGS. 6-8, the method 200 may be used to provide an ophthalmic device 100, a lens 110, and a diffractive structure 120. However, the method 200 may be used with one or more other diffractive structures 130 and / or 130'' and / or similar ophthalmic devices.

[0029] Method 200 may be performed using a system including one or more processors and a memory. The one or more processors may be configured to execute instructions stored in a memory to generate and control some or all of the processes depicted in the accompanying drawings and described below. As used herein, a processor may include one or more microprocessors, field-programmable gate arrays (FPGAs), controllers, or any other suitable computing device or resource, and memory may take the form of volatile or non-volatile memory, including but not limited to magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable memory components. The memory may store instructions for programs and algorithms that, when executed by the processor, perform the functions described herein with respect to any such processor, memory, or components, including processing functions. Furthermore, aspects of the method and system may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects. Furthermore, aspects of the present methods and systems may take the form of software components executing on at least one processor and which may be embodied in one or more computer-readable medium(s) having computer-readable program code embodied thereon.

[0030] The diffractive structure of lens 110 is designed using steps 202, 204. The step height of the echelette is determined by individually configuring each of the zones via step 202. Step 202 may be performed analytically by using a processor executing instructions. For example, the desired target focal position, focal length, zone positions, and / or other criteria may be provided as inputs to software for designing the optical grating and optimization performed. As a result, an optimized step height corresponding to an optimized phase is determined independently for some or all of the zones of the diffractive structure to be formed. Although referred to as an optimization process, those skilled in the art will recognize that the step height determined may not be optimal for the full set of criteria used. Instead, the optimization process may use analytical tools to determine the step height based on user-provided criteria. FIG. 7 is a graph 170 depicting a simplified superzonal sag profile 172 resulting from step 202. Profile 172 is simplified as a linear profile, but would more typically be curved. Thus, sag profile 172 has three zones. The optimization process resulted in an echelette of sag profile 172 that has a large optimized step height. Sag profile 172 includes the first and second orders as the main orders. For comparison, a sag profile 174 of a monofocal Fresnel lens and a sag profile 176 of a bifocal diffractive lens are shown. Sag profile 174 utilizes the first order, while sag profile 176 utilizes the zeroth and first orders. The phase corresponding to the echelette of sag profile 172 has an optimized phase greater than 2·π.

[0031] The optimized step height is folded back via step 204 if the optimized phase exceeds 2·π. The phase used in folding back is a positive integer multiplied by 2·π. In the embodiment shown, all of the zones have a large optimized step height. Eventually, the optimized step heights of all the zones are folded back. In another embodiment, the optimized step heights of only some of the zones may be folded back. FIG. 8 is a graph 170' depicting the resulting simplified sag profile 172' after folding back has been performed. The profile 172' is simplified as a linear profile, but would more typically be curved. Thus, all of the echelettes of the sag profile 172' have a reduced phase. Also shown by the dashed lines is the original curve 172 and the direction in which the sag profile 172 is moved to form the final curve 172'.

[0032] The lens 110 is fabricated via step 206. Thus, the desired diffractive structure 120 having the sag profile 170' may be formed. The diffractive structures 120, 130, 130' and / or similar diffractive structures may be provided and their advantages realized.

[0033] 9 is an exemplary embodiment of a method 210 for treating an ocular condition of a patient. For simplicity, some steps may be omitted, interleaved, and / or combined. The method 210 is also described in conjunction with using the ophthalmic device 100 and the ophthalmic lens 110. However, the method 210 may be used with one or more diffractive structures 130, 130', 170' and / or similar diffractive structures.

[0034] An ophthalmic device 100 is selected for implantation in a patient's eye via step 212. The ophthalmic device 100 includes an ophthalmic lens 110 having an individually optimized diffractive structure 120 having a folded zone 122. Thus, lenses having diffractive structures 120, 130, 130', 170' and / or similar diffractive structures may be selected for use.

[0035] The Ophthalmic Device 100 is implanted in the patient's eye via step 204. Step 204 may include replacing the patient's own lens with the Ophthalmic Device 100 or augmenting the patient's lens with the Ophthalmic Device. Treatment of the patient may then be completed. In some embodiments, implantation of another similar Ophthalmic Device into the patient's other eye may occur.

[0036] By using the method 200, the diffractive structures 120, 130, 130', 170' and / or similar diffractive structures may be used such that the advantages of one or more ophthalmic lenses 110 may be realized.

[0037] A method and system for providing an ophthalmic device has been described. The method and system have been described according to the illustrated exemplary embodiment. Those skilled in the art will readily recognize that there may be variations to the embodiment and that any variations will fall within the spirit and scope of the method and system. Accordingly, many modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims. According to aspect (1), there is provided an ophthalmic lens having at least one focal length, comprising: Front and; posterior and; at least one diffractive structure including a plurality of zones, each of the plurality of zones including at least one echelette having at least one step height, the at least one diffractive structure being on at least one of the anterior surface and the posterior surface, the at least one step height being determined individually for each of the plurality of zones; An ophthalmic lens, wherein a particular echelette in a particular one of the plurality of zones has an optimized step height that exceeds 2π, and the diffractive structure includes a first echelette and a second echelette to represent the particular echelette, the first echelette having a step height of 2π and the second echelette having a step height that is the difference between the optimized step height and 2π. According to aspect (2), the at least one focal length includes a plurality of focal lengths such that the ophthalmic lens is a multifocal lens. According to aspect (3), each of the zones is individually optimized with respect to a portion of the plurality of focal lengths. According to aspect (4), each of the zones is individually optimized with respect to the plurality of focal lengths. According to aspect (5), the at least one step height includes a plurality of step heights. According to aspect (6), the at least one step height is equal to or less than 2π. According to aspect (7), the at least one diffractive structure is incorporated within the front surface. According to aspect (8), each of the zones is individually optimized with respect to multiple target locations. According to aspect (9), there is provided a method for fabricating an ophthalmic lens having at least one focal length, performed using one or more systems, each system including one or more processors and memories, the method comprising: and designing at least one diffractive structure comprising a plurality of zones, each zone of the plurality of zones comprising at least one echelette having at least one step height, wherein designing the at least one diffractive structure further comprises: individually optimizing each zone of the plurality of zones to provide at least one optimized step height having at least one optimized phase; if the optimized phase exceeds 2π, at least one of the optimized step heights is folded back by a phase that is an integer multiple of 2π to provide at least one step height; fabricating an ophthalmic lens using the at least one step height of said at least one diffractive structure; The method includes: According to aspect (10), the at least one focal length is a plurality of focal lengths, Optimizing each of the zones individually may further include optimizing each of the zones individually with respect to at least a portion of the plurality of focal lengths. According to aspect (11), the at least one step height does not exceed 2π. According to aspect (12), the at least one diffractive structure is incorporated on the anterior surface of the ophthalmic lens. According to aspect (13), the at least one diffractive structure is incorporated on a rear surface of the ophthalmic lens. According to aspect (14), individually optimizing each zone further comprises individually optimizing each zone for a plurality of target locations.

Claims

1. 1. An ophthalmic lens having at least one focal length, Front and; Rear and; at least one diffractive structure including a plurality of zones, each of the plurality of zones including at least one echelette having at least one step height, the at least one diffractive structure being on at least one of the anterior surface and the posterior surface, the at least one step height being determined individually for each of the plurality of zones; An ophthalmic lens, wherein a particular echelette in a particular one of the plurality of zones has an optimized step height that exceeds 2π, and the diffractive structure includes first and second echelettes obtained after folding back the optimized step height that exceeds 2π by a phase that is an integer multiple of 2π, the first and second echelettes representing the particular echelette, the first echelette having a step height of 2π, and the second echelette having a step height that is the difference between the optimized step height and 2π.

2. The ophthalmic lens of claim 1 , wherein the at least one focal length comprises a plurality of focal lengths such that the ophthalmic lens is a multifocal lens.

3. The ophthalmic lens of claim 2 , wherein each of said zones is individually optimized for a portion of said plurality of focal lengths.

4. The ophthalmic lens of claim 2 , wherein each of said zones is individually optimized for said plurality of focal lengths.

5. The ophthalmic lens of claim 1 , wherein the at least one step height comprises a plurality of step heights.

6. The ophthalmic lens of claim 1 , wherein the at least one step height is less than or equal to 2π.

7. The ophthalmic lens of claim 1 , wherein the at least one diffractive structure is incorporated within the anterior surface of the ophthalmic lens.

8. The ophthalmic lens of claim 1 , wherein each of the zones is individually optimized for multiple target locations.

9. 1. A method for fabricating an ophthalmic lens having at least one focal length, executed using software by one or more systems, each including one or more processors and memory, the method comprising: and designing at least one diffractive structure comprising a plurality of zones, each zone of the plurality of zones comprising at least one echelette having at least one step height, the designing of the at least one diffractive structure further comprising: optimizing each zone of the plurality of zones individually to provide at least one optimized step height having at least one optimized phase, performed by one or more of the processors; and if the optimized phase exceeds 2π, at least one of the optimized step heights is folded back by a phase that is an integer multiple of 2π to provide at least one step height, the optimized step height being executed by one or more of the processors. designing an ophthalmic lens using the at least one step height of the at least one diffractive structure implemented by the one or more software; A method comprising:

10. the at least one focal length is a plurality of focal lengths; 10. The method of claim 9, wherein optimizing each zone individually further comprises optimizing each zone individually for at least a portion of the plurality of focal lengths, performed by one or more of the processors.

11. The method of claim 9 , wherein the at least one step height does not exceed 2π.

12. The method of claim 9 , wherein the at least one diffractive structure is incorporated on an anterior surface of the ophthalmic lens.

13. The method of claim 9 , wherein the at least one diffractive structure is incorporated into a posterior surface of the ophthalmic lens.

14. The method of claim 9 , wherein optimizing each zone individually further comprises optimizing each zone individually for a plurality of target locations, performed by one or more of the processors.

15. An ophthalmic lens having at least one focal length, comprising: at least one diffractive structure including a plurality of zones, each of the plurality of zones including at least one echelette having at least one step height, the at least one step height being determined individually for each of the plurality of zones; An ophthalmic lens, wherein a particular echelette in a particular one of the plurality of zones has an optimized step height that exceeds 2π, and the diffractive structure includes first and second echelettes obtained after folding back the optimized step height that exceeds 2π by a phase that is an integer multiple of 2π, the first and second echelettes representing the particular echelette, the first echelette having a step height of 2π, and the second echelette having a step height that is the difference between the optimized step height and 2π.

Images