Double-sided aspherical diffractive multifocal lenses, their manufacture and applications
By designing a double-sided aspherical diffractive multifocal lens, the aberration problem of existing multifocal lenses in correcting presbyopia is solved by combining aspherical and diffractive structures, achieving high contrast and enhanced visual acuity, and providing clear vision across a wide range of distances.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- APPLIED NANO MEDICAL MATERIALS TECH CO LTD
- Filing Date
- 2021-05-27
- Publication Date
- 2026-05-26
AI Technical Summary
Existing multifocal intraocular lenses have difficulty eliminating spherical aberration and astigmatic aberration simultaneously when correcting presbyopia, resulting in reduced visual contrast and visual acuity, especially under conditions of large pupils.
Design a double-sided aspherical diffractive multifocal lens. The lens body includes an aspherical front surface and a rear surface. The rear surface has multiple diffraction elements. By forming a periodic structured curve through concentric annular regions extending in the radial direction, near focal point, intermediate focal point and far focal point are generated. The optical performance of the lens is optimized by combining the aspherical surface and the diffraction structure.
It effectively eliminates spherical and astigmatic aberrations, improves visual contrast and visual acuity, provides clear vision from far to near, and enhances eye accommodation ability.
Smart Images
Figure CN115697249B_ABST
Abstract
Description
[0001] Cross-reference to related applications
[0002] This application claims priority to U.S. Serial No. 63 / 032,892, filed June 1, 2020, pursuant to 35 USC §119(e), the entire contents of which are incorporated herein by reference. Technical Field
[0003] This disclosure generally relates to ophthalmic lenses, and more specifically to novel double-sided aspheric diffractive multifocal lenses and their design, manufacture, and use. Background Technology
[0004] Ophthalmology is a medical field that involves the anatomy, physiology, and diseases of the human eye. The anatomy of the human eye is quite complex. The main structures of the eye include: the cornea, a spherical transparent tissue at the front of the eye; the iris, the colored part of the eye; the pupil, an adjustable opening in the iris that regulates the amount of light received by the eye; the lens, a small transparent disk inside the eye that focuses light onto the retina; and the retina, the layer that forms the back of the eye and converts sensed light into electrical impulses, which travel through the optic nerve to the brain. The posterior chamber (the space between the retina and the lens) is filled with aqueous humor, and the anterior chamber (the space between the lens and the cornea) is filled with the transparent, gel-like vitreous humor.
[0005] The natural lens has a flexible, transparent, biconvex structure and works with the cornea to refract light that is to be focused onto the retina. The lens is flatter on its anterior side than its posterior side, and its curvature is controlled by the ciliary muscle, which is connected to the ciliary muscle via suspensory ligaments called the suspensory ligaments. By changing the curvature of the lens, the eye's focal length is changed, thus focusing on objects at different distances. To see objects at shorter distances, the ciliary muscle contracts, and the lens thickens, resulting in a more rounded shape and therefore higher refractive power. Shifting the focus to objects at greater distances requires the lens to relax, thus increasing the focal length. This process of changing curvature and adjusting the eye's focal length to form a clear image of an object at the retina is called accommodation.
[0006] In humans, the lens in its natural environment provides approximately 18-20 diopters of refractive power, roughly one-third of the eye's total optical power. The cornea provides the remaining 40 diopters of the eye's total optical power.
[0007] As the eyes age, the lens becomes less opaque, a condition known as cataracts. Several conditions, such as diabetes, trauma, certain medications, and excessive ultraviolet radiation exposure, can also cause cataracts. Cataracts are painless and cause blurred vision. Treatment for cataracts involves surgery, which removes the cloudy lens and replaces it with an artificial lens (often called an intraocular lens (IOL)).
[0008] Another age-related effect is called presbyopia, which manifests as difficulty reading small print or seeing nearby images. Presbyopia is generally thought to be caused by the thickening and loss of elasticity of the natural lens inside the eye. Age-related changes also occur in the ciliary muscle surrounding the lens. The less elastic the muscle, the more difficult it is to focus on objects near the eye.
[0009] For example, various intraocular lenses are also used to correct other visual impairments, such as myopia or hyperopia, when excessive corneal curvature prevents the eye from seeing distant objects. The effect of myopia is that light rays from distant objects focus on a point in front of the retina, rather than directly on the surface of the retina. Hyperopia or hyperopia is caused by an abnormally flat cornea, causing light rays entering the eye to focus behind the retina, preventing them from focusing on nearby objects, and astigmatism, another common cause of visual difficulties, where images are blurred due to the irregular shape of the cornea.
[0010] In most cases, during cataract surgery, an intraocular lens (IOL) is implanted in the patient's eye to replace the natural lens and compensate for the loss of optical power from the removed lens. Modern IOL optics are designed to be multifocal, providing short-range, intermediate, and far-range vision of objects; these are also known as multifocal IOLs, or more specifically, trifocal lenses. Presbyopia can be corrected with glasses or contact lenses, and patients can also choose multifocal optics. In some cases, the IOL may include diffraction structures, thus providing not only telefocal power but also near-focal power, thereby offering a degree of ocular accommodation. However, various aberrations, such as spherical aberration and astigmatism, can adversely affect the optical performance of such lenses. For example, spherical aberration can reduce visual contrast, especially for large pupil sizes.
[0011] Therefore, what is needed is an intraocular lens that can simultaneously provide near, intermediate, and far focal points, which can also resolve the adverse effects of aberrations such as spherical and astigmatic aberrations, thereby providing enhanced contrast and improved visual acuity. Summary of the Invention
[0012] This disclosure relates to a double-sided aspherical diffractive multifocal lens that can eliminate spherical aberration and astigmatic aberration, and provide enhanced contrast and improved visual acuity. In some embodiments, the diffractive multifocal lens may include a lens body, which may include: a first aspherical surface; and a second aspherical surface including a central region and a plurality of diffractive elements, the plurality of diffractive elements including concentric annular regions extending in a radial direction, each concentric annular region having a periodically structured curve, the periodically structured curve including two smooth transition points between two sharp transition points, thereby producing a near focal point (f2), an intermediate focal point (f1), and a far focal point (f0).
[0013] In some embodiments, the first aspherical surface is the front surface, and the second aspherical surface is the rear surface. In some embodiments, the first aspherical surface may include a toric component. In some embodiments, the height distribution of the first and / or second aspherical surfaces is represented by the following formula:
[0014]
[0015] Z asp The height distribution of the aspherical structure is given by r, which is the radial distance in millimeters, c is the curvature, k is the conic constant, and A... i It is a higher-order aspherical coefficient.
[0016] In some embodiments, the height distribution of the diffraction element is represented by the following formula:
[0017]
[0018] Where λ is the design wavelength, Φ (n) (r) is the phase distribution, n1 is the refractive index of the lens material, and n0 is the refractive index of the medium covering the lens.
[0019] In some embodiments, the phase distribution Φ (n) (r) can be represented as:
[0020]
[0021] Where r is the radial distance of the lens in millimeters, r n r is the radius of the nth region. n+1 It is the radius of the (n+1)th region, and A, B, C, and D are light distribution parameters. A is the amplitude; B is the radius of the (n+1)th region. C is the period; D is the phase shift; C is the vertical shift.
[0022] In some embodiments, the phase distribution Φ (n) (r) can be -4π≤Φ (n)(r) is within the range of ≤ 4π. In some embodiments, the far focal point (f0), intermediate focal point (f1), and near focal point (f2) are within the following ranges:
[0023]
[0024] In some embodiments, the diffractive multifocal lens may be an intraocular lens (IOL). In some embodiments, the diffractive multifocal lens may further include a pair of tactile elements extending outward from the lens body. In some embodiments, the IOL is a posterior chamber IOL, and the posterior chamber IOL is configured to be implanted in the capsular bag of the human eye.
[0025] In some embodiments, this disclosure relates to a method of treating an ophthalmic disease or disorder in a subject, the method comprising implanting a diffractive multifocal lens comprising a lens body into the subject's eye, the lens body comprising: a first aspherical surface; and a second aspherical surface comprising a central region and a plurality of diffractive elements comprising concentric annular regions extending in a radial direction, each concentric annular region having a periodically structured curve comprising two smooth inflection points between two sharp inflection points.
[0026] In some embodiments, this disclosure relates to a method of manufacturing a diffractive multifocal lens, the method comprising: (a) manufacturing a first aspherical surface optionally including a torus component; (b) manufacturing a second aspherical surface; and (c) generating a central region and a diffractive element comprising a plurality of concentric annular regions on the second aspherical surface, each concentric annular region having a periodically structured curve, the periodically structured curve including two smooth inflection points between two sharp inflection points, thereby producing a near focal point (f2), an intermediate focal point (f1), and a far focal point (f0). In some embodiments, the method may further comprise performing in-situ image quality analysis to ensure that performance meets pre-established quality standards. Attached Figure Description
[0027] Figure 1A The figure shows a top view of a double-sided aspherical multifocal diffraction IOL according to some embodiments of the present disclosure;
[0028] Figure 1B A cross-sectional view of a double-sided aspherical multifocal diffraction IOL according to some embodiments of the present disclosure is shown;
[0029] Figure 2A The illustration shows an enlarged view of the lens body of an IOL according to some embodiments of the present disclosure;
[0030] Figure 2B The illustration shows the height distribution of diffraction elements according to some embodiments of the present disclosure;
[0031] Figure 2C The illustration shows the height distribution of a diffraction element according to another embodiment of the present disclosure;
[0032] Figure 3A The illustration shows the optical performance (modulation transfer function, MTF) of a first embodiment of the present disclosure with varying parameters at a 3 mm aperture and a 50 LP / mm resolution.
[0033] Figure 3B The figure illustrates the height distribution of the aspherical and diffractive combination structure according to a first embodiment of the present disclosure;
[0034] Figure 4A The illustration shows the optical performance (MTF) of a second embodiment of the present disclosure, measured at a 3 mm aperture and a 50 LP / mm resolution, with varying parameters.
[0035] Figure 4B The figure illustrates the height distribution of the aspherical and diffractive combination structure according to a second embodiment of the present disclosure;
[0036] Figure 5A The figure illustrates the optical performance (MTF) of a third embodiment of the present disclosure, measured at a 3 mm aperture and a 50 LP / mm resolution, by varying parameters.
[0037] Figure 5B The illustration shows the height distribution of the aspherical and diffractive combination structure according to a third embodiment of the present disclosure; and
[0038] Figure 6 This is a flowchart illustrating the design and fabrication of a double-sided aspherical multifocal diffraction IOL according to some embodiments of the present disclosure. Detailed Implementation
[0039] This disclosure relates to a double-sided aspheric diffractive multifocal lens and a method for designing and manufacturing such a lens in the ophthalmic field. The lens may include an aspheric front surface and an aspheric rear surface. One of the two surfaces may include multiple concentric diffractive multifocal regions. The other surface may optionally include a toric surface component. Compared to a single-sided aspheric lens, the double-sided aspheric surface design improves the modulation transfer function (MTF) of the lens-eye combination through aberration reduction and enhanced visual contrast. A surface with multiple concentric diffractive multifocal regions can produce near-focus, intermediate-focus, and far-focus areas.
[0040] Multifocal IOLs are commonly used to treat presbyopia, a condition in which the eye's ability to focus on near objects gradually weakens. Humans develop presbyopia as they age, and this effect typically begins to become noticeable around age 40-45 (when people find they need reading glasses). Presbyopic patients wearing corrective lenses may find they need two different prescriptions, ideally within the same bifocal lens—one for reading (near distance) and another for driving (far distance). Trifocal lenses can further improve vision at intermediate distances, such as when working on a computer.
[0041] Diffractive IOLs can have repeating structures that can be formed in the surface of an optical element using fabrication methods such as lathe cutting (e.g., using a lathe equipped with a cutting head made of hard minerals like diamond or sapphire), directly writing patterns using high-energy beams (e.g., laser beams or electron beams) or similar methods of ablation, etching surfaces using photolithography patterning processes, or molding surfaces. The diffraction structure is typically a series of concentric annular regions, requiring each region to gradually narrow from the center to the edge of the lens. For example, there can be approximately 5 to 30 regions between the center and the edge of the lens. The surface distribution within each region is typically a function of smooth variation, such as an arc, parabola, or straight line. At the outer periphery of each region, there are discrete steps in the vertical surface distribution. The resulting surface structure can act as a circularly symmetric diffraction grating, which disperses light into multiple diffraction orders, each with a consecutive number, such as zero, one, two, three, etc.
[0042] IOL (Inverterless Orbiter) diffractive lenses can be used to correct presbyopia. In this application, the lens may include a refractive surface and a diffractive surface. In practice, the light energy passing through a diffractive lens is typically concentrated in one, two, or three diffraction orders, while contributing negligible light energy to the other diffraction orders.
[0043] Existing designs of multifocal IOLs utilize refractive optics, combined refractive / diffractive designs, or diffractive lenses that direct light to a single diffraction order. However, fabricating such IOLs can be time-consuming and expensive. Therefore, there is a need for improved ophthalmic lenses, particularly improved diffractive IOLs that can be manufactured more easily.
[0044] This disclosure relates to an intraocular lens (IOL) that provides an extended visual range. Figure 1A A top view of a double-sided aspherical multifocal diffraction IOL 100 according to some embodiments of the present disclosure is shown. Figure 1BA cross-sectional view of a bifacial aspherical multifocal diffractive IOL 100 according to some embodiments of the present disclosure is shown. The IOL 100 may include a light-transmitting disk-shaped lens body 101 with an optical diameter 106 and a central thickness 110, and a pair of tactile elements 102, having a total outer diameter 107, serving as flexible support for the IOL when implanted in a patient's eye. The lens body 101 may include an anterior surface 108, a rear surface 109, a central region 103, and a plurality of diffractive elements 104 on the rear surface 109. The lens body 101 may include an optical axis 105 extending transversely to the anterior surface 108 and the rear surface 109. Those skilled in the art will understand that the optical axis 105 is a virtual axis for the purpose of referencing the optical characteristics of the IOL 100. The pair of tactile elements 102 may extend outwardly from the lens body 101 for supporting the IOL 100 after implantation in a human eye. In some embodiments, the tactile elements 102 of the IOL 100 may hold the IOL in proper position within a capsule.
[0045] In some embodiments, the lens body 101 may have a biconvex shape. Other shapes of the lens body 101 may include, but are not limited to, plano-convex, biconcave, plano-concave, or a combination of convex and concave shapes. In some embodiments, both the front surface 108 and the rear surface 109 may be characterized by an aspherical structure, providing a double-sided aspherical surface for the IOL 100.
[0046] The diffraction element 104 may include diffraction rings or diffraction steps, or also referred to as diffraction regions, which have characteristic radial separation to produce constructive interference at a characteristic focal point in the optical region of the IOL. In some embodiments, the diffraction element 104 may include approximately 3 to approximately 30 diffraction rings / regions. In some embodiments, the diffraction element 104 may include approximately 5, 10, 15, 20, or 25 diffraction rings / regions. The IOL may contain the diffraction element on one or both surfaces of the lens. In some embodiments, the diffraction element 104 may be placed on the rear surface of the IOL. In some embodiments, the diffraction element may be placed on the rear surface because the light scattering effect at the rear surface is less than that at the front surface. A plurality of diffraction elements 104 may include rings or regions extending concentrically through the central region 103 relative to the optical axis 105 above at least a portion of the rear surface 109 of the lens body 101. The diffraction element 104 may provide focal points at long distances, intermediate distances, and / or short distances. In some embodiments, the diffraction element 104 is not limited to concentric circular or annular regions, but may include concentric elliptical or oval regions.
[0047] In some embodiments, the optical diameter 106 of the lens body 101 may be approximately 4 mm to approximately 8 mm, while the overall outer diameter 107 of the IOL 100 including the haptic element 102 may be approximately 9 mm to approximately 18 mm. The lens body 101 may have a center thickness 110 of approximately 0.8 mm to approximately 1.2 mm. Although Figure 1A and Figure 1B The embodiments described herein relate to the posterior chamber IOL, but other ophthalmic lenses, including multifocal diffractive contact lenses or spectacle lenses, can also benefit from the same approach. When used in ophthalmic multifocal contact lenses and spectacle lenses or spectacle lenses, the tactile element 102 is not provided.
[0048] The amount of correction provided by an ophthalmic lens is called optical power and is expressed in diopters (D). Optical power is calculated as the reciprocal of a focal length f, measured in meters, which can be the corresponding focal length from the lens to the corresponding focal point for distance, intermediate, or near vision. The double-sided aspherical lens body 101 of this disclosure can provide a basic optical power of approximately 10D to approximately 25D. In some embodiments, the lens body 101 can provide a basic optical power of approximately 12D, 14D, 16D, 18D, 20D, 22D, or 24D. A plurality of diffractive elements 104 can provide additional optical powers of f1 = f0 + 2.2D and f2 = f0 + 3.3D.
[0049] IOLs can be made of flexible materials that allow for temporary deformation to reduce their overall apparent perimeter, facilitating insertion through the cornea and advantageously enabling the use of corneal incisions with reduced size. In some embodiments, the lens body may include polypropylene, polycarbonate, polyethylene, propylene-butadiene-styrene, polyamide, polychlorotrifluoroethylene, polytetrafluoroethylene, polyvinyl chloride, polyvinylidene fluoride, polyvinyl chloride, polydimethylsiloxane, polyethylene terephthalate, ethylene tetrafluoroethylene, ethylene chloride trifluoroethane, perfluoroalkoxy, polymethylpentene, polymethyl methacrylate, polystyrene, polyetheretherketone, tetrafluoroethylene, polyurethane, poly(methyl methacrylate), poly(2-hydroxyethyl methacrylate), nylon, polyether block amide, silicone, or mixtures thereof.
[0050] In some embodiments, the lens body may comprise a hydrophilic polymer made of monomers selected from the group consisting of: 2-acrylamide-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate, N-vinylpyrrolidone, vinylbenzyltrimethylammonium salt, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, diethylaminomethyl methacrylate, tert-butylaminoethyl acrylate, tert-butylaminoethyl methacrylate and dimethylaminopropylacrylamide, acrylic acid, methacrylic acid, styrene sulfonic acid and its salts, hydroxypropyl acrylate, vinylpyrrolidone, dimethacrylamide, ethylene glycol monomethacrylate, ethylene glycol monoacrylate, ethylene glycol dimethacrylate, ethylene glycol diacrylate, triethylene glycol diacrylate, and triethylene glycol methacrylate. In some embodiments, these hydrophilic monomers are surface-transferred onto the polymer matrix described in the preceding paragraph to form the lens body. In some embodiments, the IOL disclosed herein may be made of a polymer composition according to U.S. Patent No. 10,494,458, which is incorporated herein by reference in its entirety.
[0051] The tactile element of the IOL according to this disclosure may be made of polymeric materials, including but not limited to polymethyl methacrylate, polypropylene, polyethylene, polystyrene and polyacrylate.
[0052] The surface of an IOL can include spherical, aspherical, or toric elements. Spherical surfaces can lead to spherical aberration, a type of optical defect that can cause increased glare and reduce overall visual quality, especially in dim light and darkness. Aspherical lenses can correct spherical aberration. Aspherical IOLs offer improved contrast sensitivity, enhanced functional vision, and superior night driving capabilities.
[0053] Toric elements are commonly used for astigmatism correction. Astigmatism is typically an optical defect in which the eye cannot focus point objects onto a clear, focused image on the retina, resulting in blurred vision. This can be due to irregular curvature of the cornea and / or lens. The refractive error in astigmatic eyes stems from the difference in the degree of curvature of different meridians of the cornea and / or lens, and therefore the difference in the degree of refraction, resulting in the eye having two focal points, one corresponding to each meridian. As used herein, a meridian comprises one of two axes opposite to the curved surface, such as the prime meridian on Earth. Meridians can be orthogonal. For example, the Earth's meridians can be any orthogonal longitude line and any latitude line curved around the Earth's surface.
[0054] For example, in an astigmatic eye, an image may focus clearly on the retina in the horizontal (sagittal) plane, but may focus behind the retina in the vertical (tangential) plane. When astigmatism is caused solely by the cornea, the two astigmatic meridians may be the two axes of the cornea. If the astigmatism is caused by the lens, the two astigmatic meridians may be the two axes of the lens. If the astigmatism is caused by a combination of the cornea and lens, the two astigmatic meridians may be the corresponding axes of the combined lens of the cornea and lens.
[0055] Astigmatism caused by the cornea, lens, or a combination of two lenses can be corrected using lenses that include toric surfaces. A toric surface is similar to segments of a soccer ball's surface, with two regular radii of curvature, one smaller than the other. These radii can be used to correct defocusing along the two meridians of an astigmatic eye. Therefore, blurred vision caused by astigmatism can be corrected by corrective lenses or laser vision correction (e.g., eyeglasses, hard contact lenses, contact lenses, and / or IOLs), providing compensating optics for specific rotations around the optical axis.
[0056] In some embodiments, the IOL according to this disclosure is capable of providing distance vision for viewing objects at distances ranging from approximately infinity to approximately 4 meters (m). In some embodiments, the IOL according to this disclosure is capable of providing near vision for viewing objects at distances less than approximately 0.4 m. In some embodiments, the IOL according to this disclosure is capable of providing intermediate vision for viewing objects at distances ranging from approximately 0.4 m to approximately 1 m, approximately 2 m, approximately 3 m, or approximately 4 m. As a result, the IOL according to this disclosure is advantageously capable of providing a degree of ocular accommodation (often referred to as pseudo-ocular accommodation) for different distance ranges. In some embodiments, when implanted in a patient's eye, the combined focal power of the eye's cornea and the near, intermediate, and far focal powers of the IOL according to this disclosure allow light emitted from objects at near, intermediate, and far distances from the patient to be focused onto the retina. In some embodiments, the far focal point (f0), intermediate focal point (f1), and near focal point (f2) provided by the IOL according to this disclosure may have the following ranges:
[0057]
[0058] as well as
[0059]
[0060] Figure 2A An enlarged view of a lens body 101 is shown. The lens body 101 includes a front surface 108, a rear surface 109, an optical axis 105, a central region 103, and a plurality of diffraction elements 104 formed on the rear surface. The central region 103 and the diffraction elements 104 are located in... Figure 2BFurther illustration is provided. The central region begins from the 0th Fresnel zone (from d0 to d1). The diffraction elements are configured as periodically structured smooth curves (from d2 to d3), with each periodic structure of the diffraction element containing two smooth transition points (e1, e2) between two sharp transition points (d2, d3). Figure 2C Another embodiment of this disclosure is illustrated by smoothing two smoothing inflection points (e1, e2) and their periodically corresponding inflection points.
[0061] Such diffraction structures embodied in the IOL of this disclosure can be designed using equations (I) to (IV) discussed below.
[0062] Pupil function. The pupil function is a characteristic function of a lens that describes its physical effects. It can alter the state of light incident on the lens. Specifically, it is determined by the amplitude function A(r) and the phase function Φ. (n) The product representation of the exponential function of (r) is shown in the following equation (I).
[0063]
[0064] T(r): Pupil function
[0065] A(r): Amplitude function
[0066] Φ (n) (r): Phase function
[0067] n: a natural number
[0068] Phase function. The phase function is defined mathematically as a function representing the physical effects provided by a lens (e.g., the phase change (position of crests and troughs) of incident light on the lens using any method). The variable of the phase function is primarily represented by the radial position r from the center of the lens, and the phase of the light incident on the lens at position r is expressed by the phase function Φ. (n) (r) undergoes a phase change and exits the lens. Specifically, this is represented by the r-Φ coordinate system. In this disclosure, the phase is denoted by Φ, and the unit is radians. For example, one wavelength of light is represented as 2π radians, and half a wavelength as π radians. The distribution of phase in the entire region providing the phase function, represented in the same coordinate system, is called the phase distribution, or simply the distribution or region distribution. The r-axis at Φ = 0 is taken as the reference line, which means that light incident at a point where Φ = 0 is emitted without changing its phase. Furthermore, for this reference line, when Φ uses a positive value, it means that the advance of the light is delayed by that phase amount, while when Φ uses a negative value, it means that the advance of the light is advanced by that phase amount. In actual ophthalmic lenses, the refractive surface, without a given diffraction structure, corresponds to this reference line (surface). Light undergoes a phase change based on this phase function and exits the lens.
[0069] Amplitude function. The amplitude function is the function represented by A(r) in the above equation (I). In this disclosure, it is defined as a function representing the change in light transmittance as it passes through the lens. The variable of the amplitude function is represented by the position r from the center of the lens in the radial direction, and represents the transmittance of the lens at the point r. Furthermore, the amplitude function is in the range of 0 or greater and 1 or less, which means that no light is transmitted at the point A(r) = 0, and the incident light is transmitted as is without loss at the point A(r) = 1.
[0070] Zone. In this disclosure, a zone is used as the smallest unit in a diffraction structure, element, or diffraction grating provided in a lens.
[0071] Height distribution of diffraction structure on IOL (Z) diff It can be calculated based on the following equation (II).
[0072]
[0073] Z diff (r): Height distribution of the diffraction structure
[0074] Φ (n) (r): Phase function
[0075] λ: Design wavelength
[0076] n1: Refractive index of the lens material
[0077] n0: Refractive index of the medium covering the lens
[0078] The radius (r) of a specific diffraction region n It can be calculated based on the following equation (III).
[0079]
[0080] r n The radius of the nth region
[0081] λ: Design wavelength
[0082] f: the reciprocal of the additional focal length
[0083] Phase function (Φ) (n) (r) can be calculated via the following equation (IV).
[0084]
[0085] Φ (n) (r): Phase function
[0086] r: radial distance from the center of the lens
[0087] rn The radius of the nth region
[0088] r n+1 The radius of the (n+1)th region
[0089] Where A, B, C, and D are light distribution parameters. A is the amplitude; B is the optical distribution parameter. The period is C; C is the phase shift, if it is +C, the function shifts to the left, if it is -C, the function shifts to the right; D is the vertical shift, if it is +D, the function shifts upward, if it is -D, the function shifts downward.
[0090] A double-sided aspherical structure (the front and rear optical regions of the IOL) is used to correct spherical aberrations in the lens. The height distribution (Z0) of the aspherical substrate structure of the lens... asp The following equation (V) can be used to calculate:
[0091]
[0092] Z asp Height distribution of aspherical structures
[0093] r: radial distance from the center of the lens
[0094] k: Conic constant
[0095] c: curvature
[0096] A i Higher-order aspherical coefficients
[0097] According to some embodiments of this disclosure, when both the aspherical structure and the diffractive structure are placed on the same surface (the front and / or rear surface of the IOL), the height distribution (Z) of the combined structure is... total ) will be the height distribution of the aspherical structure (Z) asp ) and the height distribution of the diffraction structure (Z diff The sum of ), as calculated according to the following equation (VI).
[0098] Z total (r)=Z asp (r)+Z diff (r) Equation (VI)
[0099] Z diff Height distribution of diffraction structure
[0100] Z asphere Height distribution of aspherical structures
[0101] Z total Height distribution of the combined structure (i.e., the lens body)
[0102] In some embodiments, the lens described above may be a contact lens or an IOL. In some embodiments, the IOL may be an intracorneal IOL, an anterior chamber IOL, or a posterior chamber IOL. In some embodiments, the IOL may be a posterior chamber IOL. Although a tactile arm is illustrated in this embodiment, any suitable tactile fixation structure compatible with posterior chamber implantation for the capsular bag or ciliary sulcus may also be used in a posterior chamber IOL.
[0103] Methods for estimating the optical priority of intraocular lenses include experimentally determining their modulation transfer function (MTF). The MTF of an optical system can be measured according to Annex C of ISO 11979-2. The MTF reflects the proportion of contrast transmitted through the optical system at a defined spatial frequency of the test pattern, defined as “period / mm” or “LP / mm”, where “LP” indicates “line pair”. Generally, contrast decreases with increasing spatial frequency.
[0104] All publications, patents and patent applications mentioned in this disclosure are incorporated herein by reference to the same extent that each individual publication, patent or patent application is specifically and individually indicated to be incorporated by reference.
[0105] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. While any methods and materials similar to or equivalent to those described herein may be used in the practice or testing of this disclosure, it should be understood that modifications and variations are covered within the spirit and scope of this disclosure. Preferred methods and materials are now described.
[0106] The following are examples of different embodiments of the IOL contemplated for the applications under discussion. These examples are provided to further illustrate embodiments of this disclosure, but are not intended to limit the scope of this disclosure. While these are typical examples that may be used, other procedures, methods, or techniques known to those skilled in the art may be used alternatively.
[0107] Example
[0108] Example 1
[0109] MTF and height distribution of IOL according to the first embodiment of this disclosure
[0110] According to equation (IV), by changing parameters A, B, C, and D, and controlling the far focal point (f0), intermediate focal point (f1), and near focal point (f2), the optical performance (modulation transfer function, MTF) at a resolution of 3 mm aperture and 50 line pairs / mm (LP / mm) is as follows: Figure 3A As shown. The parameters of A, B, C, and D vary according to Table 1 below.
[0111] Table 1. Variations of parameter AD in the first embodiment of this disclosure.
[0112]
[0113]
[0114] Figure 3A The curve in the figure shows three peaks, corresponding to the far focus at approximately 14.0D, the intermediate focus at approximately 16.2D, and the near focus at approximately 17.3D.
[0115] Z-shaped structure of aspherical and diffractive combination total (r) Height distribution as follows Figure 3B As shown. The height is depicted along the vertical axis in μm. It is assumed that the optical axis passing through the center of the lens body is at a radial position r = 0, and the radial distance r measured from the optical axis in the outward direction is expressed in mm along the vertical axis.
[0116] Example 2
[0117] MTF and height distribution of IOL according to the second embodiment of this disclosure
[0118] According to equation (IV), by changing parameters A, B, C, and D, and controlling f0, f1, and f2, the optical performance (MTF) at a 3 mm aperture and a resolution of 50 line pairs / mm (LP / mm) is as follows: Figure 4A As shown. The parameters of A, B, C, and D vary according to Table 2 below. Z-axis of aspherical and diffractive combination structures total (r) Height distribution as follows Figure 4B As shown.
[0119] Table 2. Variations of parameter AD in the second embodiment of this disclosure.
[0120]
[0121]
[0122] Figure 4A The curve in the figure shows three peaks, corresponding to the far focus at approximately 24.0D, the intermediate focus at approximately 26.2D, and the near focus at approximately 27.3D.
[0123] Example 3
[0124] According to the third embodiment of this disclosure, the MTF and height distribution of the IOL
[0125] According to equation (IV), by changing parameters A, B, C, and D, and controlling f0, f1, and f2, the optical performance (MTF) at a 3 mm aperture and a resolution of 50 line pairs / mm (LP / mm) is as follows: Figure 5A As shown. The parameters of A, B, C, and D vary according to Table 3 below. Z-axis of aspherical and diffractive combination structures total (r) Height distribution as follows Figure 5B As shown.
[0126] Table 3. Variations of parameter AD in the third embodiment of this disclosure.
[0127] A B C D Ring 1 0.76 0.5 1 -0.5 Ring 2 0.41 0.5 0.5 0.24 Ring 3 -0.1 1 0.5 -0.07 Ring 4 0.45 0.5 1 -0.42 Ring 5 0.41 0.5 0.5 0.24 Ring 6 -0.1 1 0.5 -0.07 Ring 7 0.45 0.5 1 -0.42 Ring 8 0.41 0.5 0.5 0.24 Ring 9 -0.1 1 0.5 -0.07 Ring 10 0.45 0.5 1 -0.42 Ring 11 0.41 0.5 0.5 0.24 Ring 12 -0.1 1 0.5 -0.07 Ring 13 0.45 0.5 1 -0.42 Ring 14 0.41 0.5 0.5 0.24 Ring 15 -0.1 1 0.5 -0.07
[0128] Figure 5A The curve in the figure shows three peaks, corresponding to the far focus at approximately 19.0D, the intermediate focus at approximately 21.2D, and the near focus at approximately 22.3D.
[0129] Figure 6 This is a flowchart 600 illustrating the design and fabrication of a double-sided aspherical multifocal diffraction IOL according to some embodiments of the present disclosure. Step 601: Fabricating a first aspherical surface, optionally including a torus component. Step 602: Fabricating a second aspherical surface. Step 603: Generating a plurality of concentric diffraction multifocal regions on the second aspherical surface to produce a near-focal, intermediate-focal, and far-focal point. Step 604: Performing in-situ image quality analysis on the double-sided aspherical diffraction multifocal lens on an ISO Model Eye 2 for use with TRIOPTICS. The IOL PRO 2 measured the through-focus MTF to meet pre-established performance standards.
[0130] Although this disclosure has been specifically shown and described with reference to specific embodiments, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of this disclosure.
[0131] All references cited in this disclosure are incorporated herein by reference in their entirety. Features of various embodiments of this disclosure may be included in the potential claims listed in the paragraphs following this one (and before the actual claims provided at the end of this application). These potential claims form part of the written description of this application. Therefore, the subject matter of the following potential claims may be presented as actual claims in subsequent proceedings relating to this application or any application claiming priority based on this application. The inclusion of such potential claims should not be construed as meaning that the actual claims do not cover the subject matter of the potential claims. Therefore, the decision not to present these potential claims in subsequent proceedings should not be construed as a donation of subject matter to the public.
[0132] The embodiments disclosed above are intended to be exemplary only; many variations and modifications will be apparent to those skilled in the art. All such variations and modifications are intended to be within the scope of this disclosure as defined in any of the appended claims.
Claims
1. A diffractive trifocal lens, comprising a lens body, the lens body comprising: (a) The first aspherical surface; and (b) A second aspherical surface comprising a central region and a plurality of diffraction elements, the plurality of diffraction elements comprising concentric annular regions extending in a radial direction, each concentric annular region having a periodically structured curve comprising two smooth inflection points between two sharp inflection points, wherein the slope of the periodically structured curve changes sign at each of the two smooth inflection points in each of the concentric annular regions. This produces a near-focus ( f 2 ), intermediate focus ( f 1 ) and far focus ( f 0 ), The modulation transfer function (MTF) of the diffractive trifocal lens at a 3 mm aperture and a resolution of 50 LP / mm includes the modulation transfer function (MTF) at the intermediate focal point ( ). f 1 The first peak at the near-focal point and the peak at the near-focal point ( f 2 The second peak at ) and The minimum value of the MTF between the first peak and the second peak is approximately 50% of the maximum value of the MTF at the first peak.
2. The diffractive trifocal lens according to claim 1, wherein the first aspherical surface is the front surface.
3. The diffractive trifocal lens according to claim 1, wherein the second aspherical surface is the rear surface.
4. The diffractive trifocal lens according to claim 1, wherein the first aspherical surface includes a tortuous surface component.
5. The diffractive trifocal lens according to claim 1, wherein the height distribution of the first aspherical surface and / or the second aspherical surface is represented by the following formula: in The height distribution of the aspherical structure is given by r, which is the radial distance in millimeters, c is the curvature, k is the conic constant, and A i It is a higher-order aspherical coefficient.
6. The diffractive trifocal lens according to claim 1, wherein the height distribution of the diffractive elements is expressed by the following formula: in, λ is the design wavelength. Is The phase distribution within the range, where n1 is the refractive index of the lens material and n0 is the refractive index of the medium covering the lens.
7. The diffractive trifocal lens according to claim 6, wherein the phase distribution... It is represented as: Where r is the radial distance of the lens, in millimeters. n r is the radius of the nth region. n+1 Let be the radius of the (n+1)th region, and A, B, C, and D be light distribution parameters, where A is the amplitude and B is the light distribution parameter. C is the period; D is the phase shift; C is the vertical shift.
8. The diffractive trifocal lens according to claim 1, wherein the far focal point ( f 0 The intermediate focus ( f 1 ) and the near focus ( f 2 Within the following range: Where D is the diopter.
9. The diffractive trifocal lens according to claim 1, wherein the diffractive trifocal lens is an intraocular lens (IOL) designed to be inserted into the human eye.
10. The diffractive trifocal lens according to claim 9, further comprising a pair of tactile elements extending outward from the lens body.
11. The diffractive trifocal lens of claim 9, wherein the IOL is sized to be inserted into the posterior chamber of the human eye.
12. The diffractive trifocal lens according to claim 1, wherein the far focal point ( f 0 The optical power is greater than or equal to 0 diopters and less than or equal to 55 diopters.
13. The diffractive trifocal lens according to claim 1, wherein the intermediate focal point ( f 1 The optical power of the focal point is greater than that of the far focal point ( f 0 The optical power is greater than the first optical power difference, and the first optical power difference is greater than or equal to 1 diopter and less than or equal to 2.5 diopter.
14. The diffractive trifocal lens according to claim 1, wherein the near focal point ( f 2 The optical power of the focal point is greater than that of the far focal point ( f 0 The optical power is greater than the second optical power difference, and the second optical power difference is greater than or equal to 2 diopters and less than or equal to 5 diopters.
15. The diffractive trifocal lens according to claim 1, wherein the periodically structured curve is a sine curve.
16. A method for manufacturing a diffractive trifocal lens, the method comprising: (a) Manufacturing a first aspherical surface that optionally includes a complex tortuous surface component; (b) Fabricating a second aspherical surface; and (c) A diffraction element comprising a central region and a plurality of concentric annular regions is generated on the second aspherical surface, each concentric annular region having a periodically structured curve comprising two smooth inflection points between two sharp inflection points, wherein the slope of the periodically structured curve changes sign at each of the two smooth inflection points in each of the concentric annular regions, thereby producing a near-focal point. f 2 ), intermediate focus ( f 1 ) and far focus ( f 0 ), The modulation transfer function (MTF) of the diffractive trifocal lens at a 3 mm aperture and a resolution of 50 LP / mm includes the modulation transfer function (MTF) at the intermediate focal point ( ). f 1 The first peak at the near-focal point and the peak at the near-focal point ( f 2 The second peak at ) and The minimum value of the MTF between the first peak and the second peak is approximately 50% of the maximum value of the MTF at the first peak.
17. The method of claim 16, further comprising: Perform in-situ image quality analysis to measure the modulation transfer function (MTF) of the diffractive trifocal lens using a pre-established quality standard.