Multifocal lens with reduced chromatic aberration - Patents.com

Abstract

To provide a multifocal ophthalmic lens with reduced chromatic aberration. [Solution] A multifocal ophthalmic lens comprising a front surface, a rear surface, and at least one diffractive structure including a plurality of echelettes having at least two different step heights within the optical path length, greater than or equal to the wavelength of light and less than twice the wavelength of light, wherein the at least one diffractive structure is present on at least one of the front and rear surfaces, and the at least one diffractive structure provides, excluding a zeroth diffraction order, a first diffraction order at a first focus corresponding to a first focal length, a second diffraction order at a second focus corresponding to a second focal length different from the first focal length, and a third diffraction order corresponding to a third focal length different from the first focal length and the second focal length.

Description

[Technical field]

[0001] The present disclosure relates generally to ophthalmic lenses, and more particularly to multifocal ophthalmic lenses having reduced chromatic aberration. [Background technology]

[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, i.e., a single power. Objects at the focal length from the eye / IOL are in focus, while objects closer or further away may not be in focus. Although objects are only fully in focus at the focal length, objects within the depth of field (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. On the other hand, 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 distance 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 distance vision, a first diffraction order for intermediate vision, and a second diffraction order for near vision. Multifocal IOLs can improve a patient's ability to focus on distant and nearby objects. In other words, a patient's depth of focus can be enhanced.

[0004] Multifocal lenses can be used to address conditions such as presbyopia, but they have drawbacks. Multifocal IOLs can also suffer from longitudinal chromatic aberration. Different colors of light have different wavelengths and therefore different focal points. As a result, multifocal IOLs focus different colors of light at different distances from the crystalline lens. Multifocal IOLs may not be able to focus different colors of light on the patient's retina. The polychromatic image contrast of multifocal IOLs can be adversely affected, especially for distance vision.

[0005] Therefore, what is needed is a system and method for addressing chromatic aberration in multifocal IOLs. Summary of the Invention [Means for solving the problem]

[0006] The method and system provide a multifocal ophthalmic device. The ophthalmic lens has an anterior surface, a posterior surface, and at least one diffractive structure including a plurality of echelettes. The echelettes have at least one step height of at least one wavelength and no more than two wavelengths within the optical path length. A diffractive structure is present on at least one of the anterior surface and the posterior surface. The diffractive structure provides multiple focal lengths for the ophthalmic lens.

[0007] The multifocal lens may have the above-mentioned diffractive structures and may have reduced chromatic aberration, which may result in improved image quality.

[0008] 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]

[0009] [Figure 1A-B] 1A-1D depict plan and side views of an exemplary embodiment of a multifocal ophthalmic device that may have reduced chromatic aberration. [Diagram 2] 1 depicts a side view of an exemplary embodiment of a diffractive structure of a bifocal lens of an ophthalmic device that may have reduced chromatic aberration. [Figure 3A-B] 1 depicts an exemplary embodiment of a bifocal lens that may have reduced chromatic aberration and strength versus distance for a lens made without consideration of chromatic aberration reduction. [Figure 4] 1 depicts a side view of an exemplary embodiment of a diffractive structure of a trifocal lens of an ophthalmic device that may have reduced chromatic aberration. [Figure 5A-B] 1 depicts an exemplary embodiment of a trifocal lens that may have reduced chromatic aberration and strength versus distance for a lens made without consideration of chromatic aberration reduction. [Figure 6] 1 depicts a side view of an exemplary embodiment of a diffractive structure of a quadrifocal lens of an ophthalmic device that may have reduced chromatic aberration. [Figure 7A-B] 1 depicts an exemplary embodiment of a quadrifocal lens that may have reduced chromatic aberration and strength versus distance for a lens made without consideration of chromatic aberration reduction. [Figure 8] 1 depicts a side view of another exemplary embodiment of a multifocal diffractive lens for an ophthalmic device that may have reduced chromatic aberration. [Figure 9] 1 is a flowchart depicting an exemplary embodiment of a method for fabricating an ophthalmic device that may have reduced chromatic aberration. [Figure 10] 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

[0010] 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 and spectacle 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.

[0011] The method and system provide a multifocal ophthalmic device. The ophthalmic device includes an ophthalmic lens configured for use based on wavelength. The ophthalmic lens has an anterior surface, a posterior surface, and at least one diffractive structure including a plurality of echelettes. The echelettes have at least one step height within the optical path length of at least one wavelength and no more than two wavelengths. A diffractive structure is present on at least one of the anterior and posterior surfaces. The diffractive structure provides multiple focal lengths for the ophthalmic lens.

[0012] 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 drawn to scale 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, and AcrySof®. The haptics 102, 104 are used to hold the ophthalmic device 100 in place within a patient's eye (not explicitly shown). However, in other embodiments, other mechanisms may be used to hold the ophthalmic device in the appropriate 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 drawings. 1 as having a circular cross-section, other shapes may be used in other embodiments. Additionally, although described with reference to an IOL, lens 110 may be a contact lens. In such a case, haptics 102 would be omitted and lens 110 would be sized and otherwise configured to remain on the surface of the eye.

[0013] The lens 110 is 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 124. The lens 110 is determined to provide a base power, an astigmatism correction, and / or other vision correction. The lens 110 may be aspheric, toric, and / or biconic, with 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, diffractive structures 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. In such embodiments, a power compensator may be incorporated into the base curve 124 in a diffractive zone to neutralize the base diffractive power.

[0014] The lens 110 may have zones 111 corresponding to different ranges of distances perpendicular to the optical axis 116 (i.e., different radii). The zones 111 are circles or annular rings along the surface from a minimum radius to a maximum radius from the optical axis 116. The diffractive structures 120 and / or the base curve 124 may vary in different zones. For example, in some embodiments, the diffractive structures 120 may have a zone ring diameter set by a Fresnel diffractive lens criterion. Alternatively, other criteria may be used. In other embodiments, one or both of these characteristics may not vary between zones. For example, the base curve may be consistent across the entire anterior surface 112, while the diffractive structures 120 vary in the various zones 111. The diffractive structures 120 may use different diffraction orders resulting in multiple focal points as described below.

[0015] The diffractive structure 120 provides multiple focal lengths. In some embodiments, for example, 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 is configured for specific wavelengths. 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. Without more zones, such a structure would suffer from chromatic aberration.

[0016] Diffractive structure 120 includes and is formed from steps referred to as echelettes 122. As can be seen in FIG. 1B, the physical height of echelettes 122 can vary. In other embodiments, the physical height of echelettes 122 can be constant. The spacing between echelettes 122 and other features of echelettes 122 can also remain the same or vary throughout lens 110. The optical step height of echelettes 122 is their physical height (as shown in FIG. 1B) multiplied by the difference between the refractive index of lens 110 and the refractive index of the surrounding medium in which lens 110 is used.

[0017] The optical step height of the echelettes 122 can be greater than or equal to the wavelength of light and less than or equal to twice the wavelength of light. In other words, λ≦Δn·h≦2λ, where h is the physical height of the echelettes 122, λ is the wavelength of light for which the appropriate region of the diffractive structure 120 is constructed, and Δn is the refractive index difference as described above. In some embodiments, λ<Δn·h<2λ. The echelettes 122 can also be apodized (have a reduced step height), although the minimum step height of such an apodized echelette 122 is still λ. Utilizing a step height within this range eliminates the zeroth diffraction order from use in the lens 110.

[0018] In some embodiments, for example, the diffractive structure 120 is used to provide a bifocal (two focal lengths for near and far vision) lens 110. The bifocal lens 110 may utilize a first diffraction order and a second diffraction order. In some embodiments, the first diffraction order is utilized for far vision, while the second diffraction order is utilized for near vision. In other embodiments, the diffractive structure 120 may provide a trifocal (three focal lengths for near, intermediate, and far vision) lens 110. The trifocal lens 110 may utilize a first diffraction order, a second diffraction order, and a third diffraction order. In some embodiments, the first diffraction order is utilized for far vision, the second diffraction order is utilized for intermediate vision, and the third diffraction order is utilized for near vision. In other embodiments, the diffractive structure 120 is configured for a quadrifocal lens 110. Such a quadrifocal lens 110 may utilize a first diffraction order, a second diffraction order, a third diffraction order, and a fourth diffraction order. In some embodiments, the first diffraction order is used for distance vision, the second diffraction order may be empty, the third diffraction order is used for intermediate vision, and the fourth diffraction order is used for near vision. In other embodiments, the first diffraction order is used for distance vision, the second diffraction order is used for intermediate vision, the third diffraction order may be empty, and the fourth diffraction order is used for near vision. In other embodiments, different diffraction orders may be used for different focal ranges. However, the zeroth order is excluded.

[0019] The lens 110 may have improved performance while maintaining the advantages of a multifocal lens. Because the lens 110 is a multifocal lens, the ophthalmic device 100 may be used to treat conditions such as presbyopia. Other conditions may be treated and the performance of the lens 110 may be improved by the use of the base curve 124 of the lens 110, asphericity, toricity, apodization of the echelettes 122, and other features of the lens. In addition, the lens 110 may have reduced chromatic aberration. A configuration of the echelettes 122 that eliminates the zeroth diffraction order (e.g., having a step height that is at least equal to the wavelength of light and not greater than two times the wavelength of light) may reduce longitudinal chromatic aberration. In some embodiments, chromatic aberration may be significantly reduced. Thus, polychromatic or white light image contrast may be improved for distance, near, and / or intermediate vision of the multifocal lens 110. In this manner, the performance of the lens 110 and the ophthalmic device 100 may be enhanced.

[0020] The advantages of the ophthalmic lens 110 may be better understood with respect to certain bifocal, trifocal and quadrifocal embodiments. FIG. 2 depicts a side view of another exemplary embodiment of a diffractive structure 130 that may be used in the bifocal diffractive lens 110. FIGS. 3A, 3B are graphs 140, 150 depicting exemplary embodiments of intensity versus distance of a reduced chromatic aberration bifocal lens 110 made with a diffractive structure 130 and a bifocal diffractive lens made without consideration of chromatic aberration reduction, respectively. With reference to FIGS. 2-3B, the diffractive structure 130 may replace the diffractive structure 120. The diffractive structure 130 is shown with the base curve removed. FIGS. 2-3B are not to scale and are for illustrative purposes only.

[0021] Diffractive structure 130 has echelettes 132 with a single physical height h. This physical height corresponds to a single step height of lens 110. As shown in FIG. 2, the step height is greater than or equal to the wavelength for which diffractive structure 130 is configured and less than or equal to twice the wavelength for which diffractive structure 130 is configured (λ≦Δn·h≦2λ). In some embodiments, λ<Δn·h<2λ. Thus, diffractive structure 130 omits the zeroth order.

[0022] FIG. 3A is a graph 140 depicting the intensity versus distance of two wavelengths of a bifocal lens using the diffractive structure 130. The intensity versus distance of green light is shown by dashed curve 142, while the intensity versus distance of polychromatic light is shown by curve 144. FIG. 3B is a graph 150 depicting the intensity versus distance of two wavelengths of a bifocal lens without considering chromatic aberration reduction. The intensity versus distance of green light is shown by dashed curve 152, while the intensity versus distance of polychromatic light is shown by curve 154. As can be seen by comparing the graphs 140 and 150, the peaks of the curves 142 and 144 match significantly more closely than the peaks of the curves 152 and 154. The diffractive structure 130 focuses light having different wavelengths to the same approximate distance. Thus, the chromatic aberration of the diffractive structure 130 is reduced.

[0023] FIG. 4 depicts a side view of another exemplary embodiment of a diffractive structure 130' that may be used in the trifocal diffractive lens 110. FIGS. 5A, 5B are graphs 140', 150' depicting exemplary embodiments of the reduced chromatic aberration trifocal lens 110 made with the diffractive structure 130' and the intensity versus distance of a trifocal diffractive lens made without consideration of chromatic aberration reduction, respectively. The diffractive structure 130' thus omits the zeroth order. With reference to FIGS. 4-5B, the diffractive structure 130' may replace the diffractive structure 120. The diffractive structure 130' is shown with the base curve removed. FIGS. 4-5B are not to scale and are for illustrative purposes only.

[0024] Diffractive structure 130' has an echelette 132' with two distinct physical heights h1, h2. These physical heights correspond to two step heights (h1 ≠ h2) of lens 110. As shown in FIG. 4, the step heights are greater than or equal to the wavelength at which diffractive structure 130' is constructed and less than or equal to twice the wavelength at which diffractive structure 130 is constructed (λ≦Δn·h1≦2λ, λ≦Δn·h2≦2λ). In some embodiments, λ<Δn·h1<2λ, λ<Δn·h2<2λ. Thus, diffractive structure 130' omits the zeroth order.

[0025] FIG. 5A is a graph 140' depicting the intensity versus distance of green light (dashed curve 142') and polychromatic light (curve 144') for a trifocal lens using diffractive structure 130'. FIG. 3B is a graph 150' depicting the intensity versus distance of green light (dashed curve 152') and polychromatic light (curve 154') for a trifocal lens without considering chromatic aberration reduction. As can be seen by comparing graphs 140' and 150', the peaks of curves 142' and 144' match better than the peaks of curves 152' and 154'. Thus, light with various wavelengths is focused to close to the same distance. Thus, the chromatic aberration of diffractive structure 130' has been reduced.

[0026] FIG. 6 depicts a side view of another exemplary embodiment of a diffractive structure 130″ that may be used in the quadrifocal diffractive lens 110. FIGS. 7A, 7B are graphs 140″, 150″ depicting exemplary embodiments of intensity versus distance of a reduced chromatic aberration quadrifocal lens 110 made with the diffractive structure 130″ and a quadrifocal diffractive lens made without consideration of chromatic aberration reduction, respectively. With reference to FIGS. 6-7B, the diffractive structure 130″ may replace the diffractive structure 120. The diffractive structure 130″ is shown with the base curve removed. FIGS. 6-7B are not to scale and are for illustrative purposes only.

[0027] Diffractive structure 130'' has echelettes 132'' with three different physical heights, h1', h2', and h3. These physical heights correspond to three different step heights of lens 110 (h1'≠h2', h1'≠h3, h2'≠h3). As shown in FIG. 6, the step heights are greater than or equal to the wavelength at which diffractive structure 130'' is constructed and less than or equal to twice the wavelength at which diffractive structure 130 is constructed (λ≦Δn·h1'≦2λ, λ≦Δn·h2'≦2λ, λ≦Δn·h3≦2λ). In some embodiments, λ<Δn·h1'<2λ, λ<Δn·h2'<2λ, λ<Δn·h3<2λ. Thus, diffractive structure 130'' omits the zeroth order.

[0028] FIG. 7A is a graph 140'' depicting the intensity versus distance of green light (dashed curve 142'') and polychromatic light (curve 144'') for a quadrifocal lens using diffractive structure 130''. FIG. 7B is a graph 150'' depicting the intensity versus distance of green light (dashed curve 152'') and polychromatic light (curve 154'') for a quadrifocal lens without considering chromatic aberration reduction. As can be seen by comparing graphs 140'', 150'', the peaks of curves 142'', 144'' match more closely than the peaks of curves 152'', 154''. Thus, diffractive structure 130'' focuses light having different wavelengths to approximately the same distance. Thus, the chromatic aberration of diffractive structure 130'' has been reduced.

[0029] Bifocal, trifocal and / or quadrifocal lenses using diffractive structures 130, 130' and / or 130'' may have improved performance. Such lenses may have multiple focal lengths and other features that may improve treatment of a patient's vision and reduce visual artifacts. In addition, the configuration of echelettes 132, 132' and / or 132'' to eliminate the zeroth diffraction order (e.g., having a step height at least equal to the wavelength of light and not greater than two wavelengths of light) may have reduced longitudinal chromatic aberration. In some embodiments, chromatic aberration may be significantly reduced. Thus, polychromatic or white light image contrast may be improved for distance, near and / or intermediate vision of diffractive structures 130, 130' and / or 130''. Thus, the performance of lenses and ophthalmic devices made using diffractive structures 130, 130' and / or 130'' may be enhanced.

[0030] FIG. 8 depicts a side view of a portion of another exemplary embodiment of a lens 170 that may have reduced chromatic aberration. FIG. 8 is not to scale and is for illustrative purposes only. The lens 170 has a diffractive structure 172 that is a partial aperture diffractive structure. In such an embodiment, a power compensator may be incorporated into the base curve in the diffractive zone to neutralize the base diffractive power. The diffractive structure 172 has an echelette with a single distinct physical height. In other embodiments, multiple physical heights may be used. The physical height corresponds to a step height of the lens. The step height is equal to or greater than the wavelength at which the diffractive structure 170 is configured and is equal to or less than twice the wavelength at which the diffractive structure 170 is configured. The partial aperture diffractive structure 170 thus omits the zeroth order. The lens 170 may thus have improved performance as described above.

[0031] 9 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. The method 200 is also described in relation to 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.

[0032] The diffractive structures of lens 110, without regard to chromatic aberration reduction, are designed via step 202. Step 202 may include defining zone sizes and characteristics, initial step heights of echelettes, and other features of the diffractive structures. This typically results in diffractive structures with step heights that are less than the wavelength.

[0033] A specific amount is added to the step height for each echelette via step 204. Step 204 typically involves adding a wavelength to each step height. Regardless of the amount added, the resulting final step height is at least one wavelength and no more than two wavelengths. Alternatively, step 204 may include another mechanism for removing the zeroth diffraction order from the diffractive structure. Thus, the step height of the diffractive structure 120 is determined.

[0034] Lens 110 is fabricated via step 206. Thus, a desired diffractive structure 120 may be provided having a step height that is at least on the order of one wavelength and no more than two wavelengths. Diffractive structures 130, 130', 130'' and / or similar diffractive structures may be provided and their advantages realized.

[0035] 10 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 connection 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', 130'' and / or similar diffractive structures.

[0036] 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 a diffractive structure 120 with reduced chromatic aberration. Thus, lenses having diffractive structures 120, 130, 130', 130'' and / or similar diffractive structures may be selected for use.

[0037] 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.

[0038] By using the method 200, the diffractive structures 120, 130, 130', 130'' and / or similar diffractive structures may be used such that the advantages of one or more of the ophthalmic lenses 110, 110', 110'' and / or 110''' may be realized.

[0039] 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), Front and; posterior and; at least one diffractive structure including a plurality of echelettes having at least one step height within an optical path length equal to or greater than a wavelength of light and equal to or less than twice the wavelength of light, wherein the at least one diffractive structure is present on at least one of the anterior surface and the posterior surface; The at least one diffractive structure, except for a zeroth diffraction order, a first diffraction order at a first focal point corresponding to a first focal length, and a second diffraction order at a second focal point corresponding to a second focal length different from the first focal length. According to aspect (2), chromatic aberration is reduced by at least one of a base curve, a torus, an aspheric surface, apodization of the plurality of echelettes, and a diffractive structure of an aperture portion having a single distinct physical height such that the relationship between intensity and distance of polychromatic light is equivalent to the relationship between intensity and distance of monochromatic light. According to aspect (3), the lens has at least one base curve. According to aspect (4), the at least one diffractive structure is incorporated within the front surface. According to aspect (5), the at least one diffractive structure is incorporated within the rear surface. According to embodiment (6), it is formed from at least one of the following materials: silicone, hydrogel, and acrylic resin. According to embodiment (7), it has a circular cross section. According to embodiment (8), it has an aspherical, toroidal and / or biconical shape. According to aspect (9), the multifocal ophthalmic lens of claim 1 further comprises a plurality of zones, each of which corresponds to a different range of distance perpendicular to the optical axis, and each of the different zones has a different diffractive structure. According to an embodiment (10), the ophthalmic lens is selected from an intraocular lens, a contact lens, and a spectacle lens. According to aspect (11), there is provided an ophthalmic device comprising: an ophthalmic lens including an anterior surface, a posterior surface, and at least one diffractive structure including a plurality of echelettes having at least one step height within an optical path length of at least one step height equal to or greater than a wavelength of light and equal to or less than two times the wavelength of light, the at least one diffractive structure being present on at least one of the anterior surface and the posterior surface; and a plurality of haptics coupled to the ophthalmic lens, The at least one diffractive structure, except for a zeroth diffraction order, a first diffraction order at a first focal point corresponding to a first focal length, and a second diffraction order at a second focal point corresponding to a second focal length different from the first focal length. According to aspect (12), the at least one diffractive structure is incorporated within the front surface. According to aspect (13), the at least one diffractive structure is incorporated within the rear surface. According to aspect (14), a multifocal ophthalmic device as described in claim 11 further comprising a plurality of zones, each of the plurality of zones corresponding to a different range of distance perpendicular to the optical axis, and each of the different zones having a different diffractive structure. According to an aspect (15), the portion having a single distinct physical height further includes one of a base curve, a torus, an aspheric surface, an apodization of the plurality of echelettes, and a diffractive structure of an aperture. According to an aspect (16), there is provided a method for producing a multifocal ophthalmic lens, comprising the steps of: designing an ophthalmic lens configured for use based on a wavelength; The ophthalmic lens to be designed has an anterior surface, a posterior surface and at least one diffractive structure; the at least one diffractive structure includes a plurality of echelettes having at least one initial step height and is present on at least one of the anterior surface and the posterior surface; The at least one diffractive structure, except for a zeroth diffraction order, a first diffraction order at a first focal point corresponding to a first focal length, and a second diffraction order at a second focal point corresponding to a second focal length different from the first focal length; The method further comprises: adding one wavelength to the at least one initial step height to provide at least one final step height; manufacturing the ophthalmic lens using the at least one final step height for the at least one diffractive structure; A method for producing a multifocal ophthalmic lens, comprising: According to aspect (17), the at least one diffractive structure is incorporated within the front surface. According to aspect (18), the at least one diffractive structure is incorporated within the rear surface. According to aspect (19), the ophthalmic lens further comprises a plurality of zones, each of the plurality of zones corresponding to a different range of distance perpendicular to the optical axis, and each of the different zones having a different diffractive structure.

Claims

1. The front and The rear and a plurality of echelettes of a diffractive structure of the multifocal ophthalmic lens have a single physical height, the plurality of echelettes having a step height within an optical path length that is equal to or greater than a wavelength of light and equal to or less than twice the wavelength of light, the diffractive structure being present on at least one of the anterior surface and the posterior surface; The diffractive structure, except for the zeroth diffraction order, a first diffraction order at a first focal point corresponding to a first focal length; and a second diffraction order at a second focal point corresponding to a second focal length different from the first focal length.

2. 2. The multifocal ophthalmic lens of claim 1, wherein chromatic aberration is reduced by at least one of a base curve, a torus, an aspheric surface, apodization of the plurality of echelettes having a single physical height, and the diffractive structure, so that the relationship between the intensity and distance of polychromatic light is equivalent to the relationship between the intensity and distance of monochromatic light.

3. The multifocal ophthalmic lens of claim 1 , wherein the multifocal ophthalmic lens has at least one base curve.

4. The multifocal ophthalmic lens of claim 1 , wherein the diffractive structure is incorporated within the anterior surface.

5. The multifocal ophthalmic lens of claim 1 , wherein the diffractive structure is incorporated within the posterior surface.

6. 10. The multifocal ophthalmic lens of claim 1, formed from at least one of the following materials: silicone, hydrogel, and acrylic.

7. The multifocal ophthalmic lens of claim 1 having a circular cross section.

8. The multifocal ophthalmic lens of claim 1 having an aspheric, toric and / or biconic shape.

9. The multifocal ophthalmic lens of claim 1 further comprising a plurality of zones, each of said plurality of zones corresponding to a different range of distance perpendicular to the optical axis, and each of said different zones having a different diffractive structure.

10. The multifocal ophthalmic lens of claim 1 , wherein the multifocal ophthalmic lens is selected from an intraocular lens, a contact lens, and a spectacle lens.

11. 1. A multifocal ophthalmic device comprising: an ophthalmic lens including an anterior surface, a posterior surface, a plurality of echelettes, the diffractive structure of the ophthalmic lens being comprised of the plurality of echelettes having a single physical height, the diffractive structure being present on at least one of the anterior surface and the posterior surface ... comprised of the plurality of echelettes having a step height within an optical path length that is equal to or greater than a wavelength of light and equal to or less than twice the wavelength of light; and a plurality of haptics coupled to the ophthalmic lens, The diffractive structure, except for the zeroth diffraction order, a first diffraction order at a first focal point corresponding to a first focal length; and a second diffraction order at a second focal point corresponding to a second focal length different from the first focal length.

12. The multifocal ophthalmic device of claim 11 , wherein the diffractive structure is incorporated within the anterior surface.

13. The multifocal ophthalmic device of claim 11 , wherein the diffractive structure is incorporated within the posterior surface.

14. 12. The multifocal ophthalmic device of claim 11 further comprising a plurality of zones, each of said plurality of zones corresponding to a different range of distance perpendicular to the optical axis, and each of said different zones having a different diffractive structure.

15. 12. The multifocal ophthalmic device of claim 11, further comprising at least one of a base curve, a torus, an aspheric surface, an apodization of said plurality of echelettes having a single physical height, and said diffractive structure.

16. 1. A method for making a multifocal ophthalmic lens, comprising: designing an ophthalmic lens configured for use based on a wavelength; The ophthalmic lens to be designed has an anterior surface, a posterior surface and at least one diffractive structure; the at least one diffractive structure includes a plurality of echelettes having at least one initial step height and is present on at least one of the anterior surface and the posterior surface; The at least one diffractive structure, except for a zeroth diffraction order, a first diffraction order at a first focal point corresponding to a first focal length; and a second diffraction order at a second focal point corresponding to a second focal length different from the first focal length; The method further comprises: adding one wavelength to the at least one initial step height to provide at least one final step height; manufacturing the ophthalmic lens with the at least one final step height for the at least one diffractive structure; A method for producing a multifocal ophthalmic lens, comprising:

17. The method of claim 16 , wherein the at least one diffractive structure is incorporated within the front surface.

18. The method of claim 16 , wherein the at least one diffractive structure is incorporated within the posterior surface.

19. 17. The method of claim 16, wherein the ophthalmic lens further comprises a plurality of zones, each zone of the plurality of zones corresponding to a different range of distances perpendicular to the optical axis, and each different zone having a different diffractive structure.

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