CN219089775U - Astigmatism correction type intraocular lens - Google Patents

Abstract

The present utility model relates to an astigmatism-correcting intraocular lens. Specifically, an astigmatism-correcting intraocular lens includes an optical portion having an anterior optical surface and a posterior optical surface, wherein at least one of the anterior optical surface or the posterior optical surface is toric; and a haptic connected to the optic portion at an edge of the optic portion; wherein the edge of the optical portion has an edge thickness of 0.18mm-0.38mm at the 45 ° meridian and the difference in edge thickness of the edge of the optical portion over the entire meridian is 0.02mm-0.22mm.

Description

Astigmatism correction type intraocular lens

Technical Field

The present application relates to intraocular lenses, and more particularly to astigmatic intraocular lenses.

Background

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named applicant, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

Intraocular lenses (IOLs) are intraocular lenses that are implantable in the eye to replace the natural lens of the eye, which becomes clouded, for example, by cataracts, and function to restore vision. The intraocular lens is widely applied to the cataract medical field, the cloudy lens is removed after cataract surgery, the intraocular lens is implanted into the eye to replace the original lens, and an external object is focused and imaged on the retina, so that the purpose of clearly seeing surrounding scenes is achieved.

Refractive error of the eye is one of the causes that can significantly affect imaging quality, and astigmatism is a condition of refractive error of the eye. Astigmatism is caused by inconsistent curvature of the cornea or lens surface, such as rugby, resulting in different optical powers of two meridians perpendicular to each other, and thus failing to focus on a point on the retina, resulting in an unclear or overlapping image. Astigmatism is classified into regular astigmatism and irregular astigmatism. The two meridians with the largest difference in refractive power are principal meridians, which are perpendicular to each other and are regular astigmatism, which can be corrected by the lens. The astigmatism and the curvature of each meridian are inconsistent, and are irregular astigmatism.

Senile cataract combined with corneal astigmatism is a common refractive error. In the human eye with cornea astigmatism, although the cataract problem can be solved by simply implanting a single Jiao Fei spherical intraocular lens, the patient still suffers from the influence of astigmatism on vision and has poor vision, and the purpose of taking off the lens cannot be achieved. An astigmatism correcting intraocular lens (Toric IOL) is an intraocular lens for solving the problem of cataract accompanied by astigmatism, which corrects corneal astigmatism while achieving normal refractive power.

Astigmatism correcting intraocular lenses have stringent requirements for alignment of the IOL's axis of astigmatism with the cornea's axis of astigmatism, and therefore have high requirements for rotational stability after lens implantation due to their special axial positions, which would otherwise affect the correction of astigmatism.

In view of this, there is a continuing need in the art to obtain an astigmatism-correcting intraocular lens with high rotational stability to both correct astigmatism and achieve good refractive results.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In one aspect of the present application, there is provided an astigmatism-correcting intraocular lens comprising: an astigmatism correcting intraocular lens comprising: an optical portion having a front optical surface and a rear optical surface, wherein at least one of the front or rear optical surfaces is a toric surface; and a haptic connected to the optic portion at an edge of the optic portion; wherein the edge of the optical portion has an edge thickness of 0.18mm-0.38mm at the 45 ° meridian and the difference in edge thickness of the edge of the optical portion over the entire meridian is 0.02mm-0.22mm.

Preferably, one of the front or rear optical surfaces is toric and the other of the front or rear optical surfaces is aspherical.

Preferably, wherein the anterior and posterior optical surfaces are toric.

Preferably, points or continuous short lines or dash lines distributed at discrete equal intervals are provided as marks on the optical surface on which the toric surface is located, to indicate the meridian at which the toric diopter is minimum.

Preferably, the marks are located outside an aperture of 4.5mm of the optical surface.

Preferably, the marks are located outside an aperture of 4.7mm of the optical surface.

Preferably, the toric surface satisfies:

wherein C _x C is the curvature of the meridian plane with the greatest refractive power _y K is the curvature of a meridian plane perpendicular to the meridian plane of minimum refractive power _x ，K _y ，A _i ，B _i The conic coefficient and the higher-order aspheric coefficient on the meridian plane with the largest refractive power and the meridian plane with the smallest refractive power are respectively, and X and Y are respectively coordinates on the corresponding meridian planes.

Preferably, the intraocular lens has an equivalent sphere power of 10D to 30D and a cylinder power of 0.75D to 10D.

Preferably, the effective light transmission diameter of the optical portion is 6mm or more.

Preferably, the haptics are L-shaped or C-shaped haptics and have a contact angle of 45 ° to 70 °.

Preferably, the haptics are disposed in a manner that bisects the circumference of the optic portion.

Preferably, the intraocular lens is made of a hydrophobic acrylate material.

The above features and advantages and other features and advantages of the present application are readily apparent from the following detailed description of the preferred embodiments and best modes for carrying out the present application when taken in connection with the accompanying drawings and appended claims.

Drawings

Other features, advantages and details appear, by way of example only, in the following detailed description of embodiments, the detailed description referring to the drawings in which:

fig. 1 is a schematic view of an astigmatism-correcting intraocular lens according to the present application.

Fig. 2 is an edge thickness distribution at each meridian plane at different cylinder powers according to the present application.

Fig. 3 is an edge thickness profile for different equivalent sphere power ranges for the same cylinder power according to the present application.

Detailed Description

The following description is merely exemplary in nature and is not intended to limit the present application, uses, or uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, and brief summary or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts or features.

The utility model will now be further elucidated. In the following paragraphs, the different aspects of the present application are defined in more detail. Each aspect so defined may be combined with any other aspect(s) unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature(s) indicated as being preferred or advantageous.

Referring to fig. 1, an astigmatism correcting intraocular lens (Toric IOL) 6 is generally composed of an optic portion 1 and haptics 2. The optical portion 1 has a front optical surface 3 and a rear optical surface 4 for producing different optical powers; the haptics 2 are attached to the optic portion 1 at its edges for mechanical support of the optic portion after implantation of the IOL in the capsular bag. As is generally understood by those skilled in the art, herein, "edge of the optic portion" refers to the area of the outer edge 5 of the optic portion 1 of the intraocular lens 6 that does not affect the optical characteristics of the intraocular lens. The magnitude of the intraocular lens power is primarily determined by the radius of curvature of the anterior optical surface, the radius of curvature of the posterior optical surface, and the center thickness, with the radius of curvature of the anterior and posterior optical surfaces being the primary determinants.

The optic portion 1 and haptics 2 of the intraocular lens may be made of the same material, such as polymethyl methacrylate or PMMA, silicone, hydrogels, acrylates, and the like. In particular, acrylate materials are classified into hydrophilic and hydrophobic type, and hydrophobic type acrylate is widely used in the current intraocular lens materials because of its characteristics of high refractive index, high ductility, etc. Advantageously, the intraocular lenses of the present application are made using hydrophobic acrylate materials.

In the astigmatism-correcting intraocular lens IOL of the present application, the optical design employs a toric design. In other words, at least one of the front optical surface 3 and the rear optical surface 4 of the optical portion 1 is of toric design. For example, in an intraocular lens designed according to the principles of the present application, anterior optical surface 3 of optic portion 1 may be of toric design and posterior optical surface 4 may be of aspherical design; in another intraocular lens designed according to the principles of the present application, the anterior optical surface 3 of the optic portion 1 may be of aspherical design and the posterior optical surface 4 of the intraocular lens may be of toric design; in yet another intraocular lens designed according to the principles of the present application, both the anterior optical surface 3 and the posterior optical surface 4 of the optic portion 1 may be toric in design.

As will be appreciated by those skilled in the art, astigmatism correcting intraocular lenses impose stringent requirements on the alignment of the IOL's axis of astigmatism with the axis of astigmatism of the cornea, as the IOL has its particular axial position so as to have proper rotational stability after the intraocular lens is implanted in a human eye. Typically, the effect of correcting astigmatism will be reduced by 3.3% for each 1 rotation of the axial position of the intraocular lens. When the rotation is greater than 30 deg., the intraocular lens needs to be removed from the human eye and the procedure is re-performed. Therefore, the rotational stability of the astigmatism-correction intraocular lens has a great influence on the effect after the astigmatism-correction operation.

Because the optical design of an astigmatic intraocular lens employs a toric design, the toric optical characteristics are such that it has different radii of curvature on different meridian planes, and thus it has only axial symmetry, and not rotational symmetry. As described above, in a human eye in which there is corneal astigmatism, the cornea has a certain astigmatism power, and the axis of the large refractive power is generally indicated as the astigmatism axis; the application of an astigmatic intraocular lens is to mark the axial position on a meridian plane where the refractive power is small, by placing an indicator line on the optical plane that marks the axial position of the astigmatism. Referring back to fig. 1, there is shown an astigmatism axis 7 which serves to indicate the meridian plane of minimum diopter of an astigmatism correcting intraocular lens. In the surgical procedure of implanting an intraocular lens into a human eye, the purpose of correcting astigmatism can be achieved by aligning the indicator line with the corneal axis so that the two axes are aligned.

However, as previously mentioned, due to the special toric design of the astigmatic lens, it has non-rotational symmetry, that is to say the thickness of the edge of the optical portion is not constant, that is to say will vary with the meridian position. This will cause the intraocular lens to experience a difference in stress in different directions after implantation in the human eye and will cause a significant increase in stress instability with increasing astigmatism. This is also why the probability of rotation of an intraocular lens of large astigmatism power is greater than that of an intraocular lens of small astigmatism power.

In an intraocular lens, there are 360 meridian lines when dividing its circumference by 1 °, one meridian line having the lowest refractive power and having a large radius of curvature, and the other meridian line perpendicular thereto having the highest refractive power and having a small radius of curvature. As understood, the characterizing parameters of the power of an astigmatic intraocular lens are equivalent sphere power, and the equivalent sphere power and cylinder power of an astigmatic intraocular lens can be expressed as:

equivalent sphere power= (power of lowest power meridian + power of highest power meridian)/2;

cylinder = power of highest power meridian-power of lowest power meridian.

Typically, the axial position of an astigmatism correcting lens will be marked in the lowest power orientation for alignment with the highest power meridian of the cornea of the eye. The IOL has the thinnest corresponding edge thickness on the lowest power meridian and the thickest corresponding edge thickness on the highest power meridian, with the edge thicknesses of other meridian orientations being intermediate between these two thicknesses. In the astigmatic lens of the present application, marks are provided on the optical surface of the toric design, such as discrete equally spaced dots or continuous dashes or dashes to indicate the meridian of least diopter, i.e. the location of the thinnest edge thickness. The placement of the indicator facilitates surgeon positioning and alignment of the IOL during and after surgery. Advantageously, the mark is located outside the aperture of 4.5mm of the optical face, preferably the mark is located outside the aperture of 4.7 mm.

The inventors of the present application have discovered that optimizing and controlling the thickness of the edge of the optical portion of the IOL, and in particular the amount of variation in the thickness of the edge, is important in performing the Torr IOL design, which is effective in improving the rotational stability of the astigmatic lens. When the edge thickness of the optical portion is within a certain range, its influence on the optical portion including axial displacement, rotational stability (rotational moment) is reduced to an acceptable level. For IOLs, the edge thickness increases with power for different equivalent sphere powers with the same cylinder power. The edge thickness of the optical portion of an astigmatism-correcting IOL varies periodically, particularly in sine or cosine, so that the difference in edge thickness thereof is not constant, thereby affecting the rotational stability of the lens. When the thickness of the edge of the optical portion is limited to a certain extent, its influence on the axial displacement, rotational stability, is reduced to an acceptable level. By controlling the edge thickness of the optic portion of the IOL, and in particular controlling the variation in edge thickness of the optic portion, the rotational stability of the astigmatic IOL can be advantageously improved.

According to the present application, at least one of the anterior 3 and posterior 4 optical surfaces of the optical portion 1 of an astigmatism correcting intraocular lens IOL is of toric design, wherein the toric surface satisfies:

，

wherein C is _x For curvature in one of the meridian directions (typically the meridian plane of high refractive power), C _y For curvature in the other meridian direction perpendicular thereto (typically the meridian plane of small refractive power), similarly, K _x ，K _y ，A _i ，B _i For the conic coefficient and the higher-order aspheric coefficient on the two meridian planes, X and Y are coordinates on the corresponding meridian planes, respectively.

According to the present application, the edge of the optical portion has an edge thickness of 0.18mm-0.38mm at the 45 ° meridian, and the difference in thickness of the edge of the optical portion over the entire meridian is 0.02mm-0.22mm. The inventors have discovered that by doing so, the rotational stability of the IOL is greatly improved. In particular, this has a very good effect on optimizing the imaging quality of an IOL at large effective clear apertures, e.g., greater than 6mm, and is beneficial in suppressing or eliminating stray light. The astigmatism-correcting IOL of the present application is capable of achieving equivalent sphere power of 10D-30D and cylinder power of 0.75D-10D.

In addition, the inventors have discovered that by designing an IOL to have a relatively large contact angle, the contact area with the capsular bag after implantation of the IOL can be increased, and the stability of the IOL can be further increased. For example, in this application, IOLs have L-shaped or C-shaped haptics with contact angles between 45 ° -70 °. It is particularly advantageous that the haptics of the IOL be arranged in a manner that bisects the circumference of the optic portion to improve lens stability and thereby improve imaging.

Example 1

One of the optic portions of the astigmatism correcting IOL is toric and the other is aspherical, the edges of the optic portion have an edge thickness of 0.18mm-0.38mm at the 45 ° meridian and the difference in thickness of the edges of the optic portion over the entire meridian is 0.02mm-0.22mm. See table one for specific data.

The thickness of 45-degree meridian plane and the thickness difference on the whole optical surface of the optimal design under different cylindrical power are shown

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Taking the example of the 45 degree meridian with the edge thickness of 0.27mm, the minimum difference of the edge thickness of 0.02mm and the maximum difference of the edge thickness of 0.22mm (see fig. 2), the rotation stability of the lens can be well controlled by controlling the difference of the edge/center thickness and the edge thickness under the same lens structural design as known from the changes of the rotation moment value and the axial displacement of the second table.

Simulation data schematic of two different cylinder powers

As can be seen from the above design results, when the edge thickness at the 45 ° meridian is controlled to be the same in different designs (different cylinder powers), different edge thickness differences (caused by different cylinder power designs) in the full meridian plane have no obvious difference in moment and axial displacement; in the design of full-series cylindrical power 0.75D-10.0D, the equivalent level of no obvious difference between moment and axial displacement can be achieved under a certain edge thickness difference. It has been shown that control of the rotational moment and control of the axial displacement can be achieved by controlling the edge thickness design and edge thickness differential, thereby providing good control over the rotational stability of the IOL of the design.

Example 2:

and for the same cylindrical power, different equivalent spherical powers and the same variable control, the design is optimized by controlling the edge thickness so as to meet the requirements of the optical parameter design index. Taking the following design with 6.0D cylinder power and 10D, 20D and 30D equivalent sphere power as examples, the edge thickness distribution in the full equivalent sphere power range (10D-30D) is shown in fig. 3 by optimizing the edge thickness in the 45 ° meridian direction to be 0.27mm, and the whole design edge thickness variation to be 0.13 mm.

Under the same cylinder power, design parameters in different equivalent sphere power ranges are shown in a table III.

Design parameter representation in different equivalent sphere range under same column power

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments described herein are only examples, and are not intended to limit the scope, applicability, or configuration of the application in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the application as set forth in the appended claims and the legal equivalents thereof.

Claims (12)

1. An astigmatism correcting intraocular lens comprising:

an optical portion having a front optical surface and a rear optical surface, wherein at least one of the front or rear optical surfaces is a toric surface; and a haptic connected to the optic portion at an edge of the optic portion;

wherein the edge of the optical portion has an edge thickness of 0.18mm-0.38mm at the 45 ° meridian and the difference in edge thickness of the edge of the optical portion over the entire meridian is 0.02mm-0.22mm.

2. The astigmatic intraocular lens of claim 1 wherein one of the anterior or posterior optical surfaces is toric and the other of the anterior or posterior optical surfaces is aspheric.

3. The astigmatic intraocular lens of claim 1 wherein the anterior and posterior optical surfaces are toric.

4. An astigmatism correcting intraocular lens according to claim 2 or 3 wherein points or continuous short or dash lines distributed at discrete equidistant intervals are provided as marks on the optical surface on which the toric surface lies to indicate the meridian of minimum refractive power of the toric surface.

5. The astigmatic intraocular lens of claim 4 wherein the marks are located outside an aperture of 4.5mm of the optical surface.

6. The astigmatic intraocular lens of claim 5 wherein the marks are located outside an aperture of 4.7mm of the optical surface.

7. An astigmatism correcting intraocular lens according to claim 2 or claim 3 wherein the toric surface satisfies:

wherein C _x C is the curvature of the meridian plane with the greatest refractive power _y K is the curvature of a meridian plane perpendicular to the meridian plane of minimum refractive power _x ，K _y ，A _i ，B _i The conic coefficient and the higher-order aspheric coefficient on the meridian plane with the largest refractive power and the meridian plane with the smallest refractive power are respectively, and X and Y are respectively coordinates on the corresponding meridian planes.

8. The astigmatism correcting intraocular lens of claim 7 wherein the intraocular lens has an equivalent sphere power of 10D to 30D and a cylinder power of 0.75D to 10D.

9. The astigmatic intraocular lens of claim 8 wherein the optical portion has an effective clear diameter of 6mm or greater.

10. An astigmatic intraocular lens according to claim 8 or 9 wherein the haptics are L-shaped or C-shaped and have a contact angle of 45 ° to 70 °.

11. The astigmatic intraocular lens of claim 10 wherein the haptics are disposed in a manner that bisects the circumference of the optic portion.

12. The astigmatic intraocular lens of claim 11 wherein the intraocular lens is made of a hydrophobic acrylate material.

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