CN111166558A

CN111166558A - Capsular bag tension ring

Info

Publication number: CN111166558A
Application number: CN201811331217.5A
Authority: CN
Inventors: 周建; 刘丁枭
Original assignee: Abbott (beijing) Medical Technology Co Ltd
Current assignee: Abbott (beijing) Medical Technology Co Ltd; Eyebright Medical Technology Beijing Co Ltd
Priority date: 2018-11-09
Filing date: 2018-11-09
Publication date: 2020-05-19
Also published as: WO2020094119A1

Abstract

The present invention relates to a capsular tension ring for easy and safe implantation having a smooth transition portion between the main body and the positioning portion. The radius of curvature of the inner contour of the transition portion, viewed in a direction perpendicular to the plane of the capsular tension ring, is 0.8mm to 5.0 mm. The capsular bag tension ring can avoid the phenomenon of stress concentration when being implanted, and reduces the risk of fracture.

Description

Capsular bag tension ring

Technical Field

The invention relates to a capsular tension ring. The capsular bag tension ring provided by the invention can avoid the stress concentration phenomenon during implantation, and reduces the risk of fracture.

Background

The capsular tension ring is a compressibly deformable, generally annular member with an opening. Prior to implantation in the capsular bag, the capsular tension ring is compressed and the outer diameter is reduced such that the capsular tension ring has a tendency to expand outwardly. After implantation of the capsular bag, the capsular tension ring expands outwardly, stretching the collapsed capsular bag into a circular shape. The capsular tension ring is tightly attached to the capsular bag membrane after being implanted into the capsular bag, so that the tension of the capsular bag can be maintained, the rear capsular membrane is prevented from being folded, the capsular bag is resisted from being contracted, and the integrity of the capsular bag is maintained. The capsular tension ring includes a substantially annular main body and positioning portions at both ends of the main body, the positioning portions having positioning holes. The cross section of the main body of the existing capsular tension ring is mostly circular, oval, rectangular or polygonal. The capsular tension ring is implanted into the capsular bag through an implanter and is used for treating congenital subluxation of crystalline lens, rupture of zonules before or during operation, weakness of zonules, and risk of capsular shrinkage, especially for patients with high myopia.

The implantation of the capsular bag tension ring and the implantation of the intraocular lens are in many cases performed simultaneously. The capsular tension ring of the rectangular cross-section or polygonal cross-section body may inhibit and prevent proliferation and migration of lens epithelial cells. Posterior capsular opacification is caused by proliferation and migration of lens epithelial cells remaining after cataract surgery between the posterior surface of the intraocular lens and the posterior capsular sac membrane, and thus capsular tension rings of an implanted rectangular-cross-section or polygonal-cross-section body may prevent the posterior capsular opacification from occurring.

Existing capsular tension rings are typically made of PMMA, which has some brittleness. Due to the small radius of curvature at the transition between the main body and the positioning portion, a fracture often occurs between the positioning portion and the main body when implanted with the implant. If a rupture occurs while the capsular tension ring is loaded, fragments of the ruptured capsular tension ring are extraocular and a direct replacement of a new capsular tension ring may be selected. If the capsular bag is broken during the process of implanting into the eye, fragments of the broken capsular bag tension ring can be scattered in the eye tissue, the scattered fragments need to be cleaned out, and the capsular bag tension ring is a tedious and obliged thing for a doctor, and once the fragments are left in the eye, the ocular tissue can be injured. The least desirable thing for the surgeon is that the capsular tension ring break during implantation.

Prior implants for implanting capsular tension rings are shown in fig. 1, where a slightly curved elongated guide tube on the left side is visible.

To facilitate micro-incision implantation, the smaller the inner and outer diameters of the guide tube of the implanter, the better. The smaller the diameter of the guide tube, the smaller the incision required for implanting the tension ring, and the less trauma to the patient, the more beneficial to postoperative recovery and complications reduction, etc. The guide tube of the existing implanter has an inner diameter of 1.1-1.3 mm and an outer diameter of 1.6-1.8 mm.

When implanting the capsular tension ring, the capsular tension ring needs to be loaded (pulled) into the implanter. Firstly, pushing out a push needle from an implanter guide pipe by pressing the rear end of a push rod of the implanter, hooking a hook at the front end of the push needle on one positioning hole of a bag tension ring, then loosening the implanter push rod, slowly drawing the bag tension ring into the implanter guide pipe, and deforming the shape of the bag tension ring to adapt to the shape of the implanter guide pipe. During surgical implantation, the capsular tension ring loaded into the implanter guide tube is pushed out by pressing the implanter push rod, the capsular tension ring is implanted into the intraocular capsular bag through the corneal incision, and the capsular tension ring is ensured to be unfolded in the clockwise direction in the capsular bag. After the capsular tension ring is implanted into the correct position, the capsular tension ring is released through the capsular tension ring positioning hole. After complete release of the capsular tension ring, the implanter is carefully removed to complete implantation of the capsular tension ring.

The positioning parts at two ends of the approximately circular main body of the capsular tension ring are provided with positioning holes, so that a steel wire of an implanter can be conveniently inserted into the positioning holes to hook the capsular tension ring in the operation process and then implanted into the capsular bag. The transition between the positioning portion and the main body of the prior capsular tension ring is narrow and has a small radius of curvature, as shown in fig. 2. When pulling the capsular tension ring into the implanter, the tension ring inevitably contacts and exerts a force on the implanter guide tube due to the small inner diameter of the implanter guide tube and is made of rigid metal. If the force is large, breakage easily occurs between the main body of the tension ring and the positioning portion. In addition, the same problem may arise during the pushing of the tension ring out of the implant.

Disclosure of Invention

The present invention provides a pouch tension ring, comprising: a generally annular body having a first end and a second end; a generally circular first positioning portion having a first positioning aperture; a substantially circular second positioning portion having a second positioning hole; a first transition portion forming a smooth transition between the first positioning portion and the first end; a second transition portion forming a smooth transition between the second positioning portion and the second end; a notch located between the first and second positioning portions; wherein the first and second locating portions have an outer diameter dimension greater than the cross-sectional dimension of the main body, and wherein the radius of curvature of the inner contour of the first and/or second transition portion, as viewed in a direction perpendicular to the plane of the capsular tension ring, is from 0.8mm to 5.0 mm, preferably from 2.0 mm to 3.0 mm, more preferably from 2.0 mm to 2.5 mm.

In one embodiment, the body has a diameter of 11 mm to 15 mm, preferably 12 mm to 14 mm, more preferably 12 mm to 13 mm.

In one embodiment, the cross-section of the body is circular, rectangular or polygonal.

In one embodiment, the body is circular in cross-section and has a diameter of 0.18 mm to 0.25 mm, preferably 0.20 mm to 0.24 mm, more preferably 0.21 mm to 0.23 mm.

In one embodiment, the width of the notch is 4 mm to 8mm, preferably 6mm to 8mm, more preferably 6mm to 7 mm.

In one embodiment, the first and second locating portions have an outer diameter of 0.60 to 0.85 mm, preferably 0.65 to 0.75 mm, more preferably 0.65 to 0.70 mm.

In one embodiment, the capsular tension ring is made of a material having a poisson's ratio of 0.2 to 0.4, preferably 0.25 to 0.35, more preferably 0.30 to 0.32.

In one embodiment, the capsular tension ring is made of a material having a Young's modulus of 1 GPa to 30 GPa, preferably a material having a Young's modulus of 2 GPa to 20 GPa, more preferably a material having a Young's modulus of 3 GPa to 10 GPa, and more preferably a material having a Young's modulus of 3 GPa to 5 GPa.

In one embodiment, the inner contour of the first transition portion and/or the second transition portion is a circular arc or a parabola, as viewed in a direction perpendicular to the plane of the capsular tension ring.

Drawings

Figure 1 schematically illustrates a prior art implanter for implanting a capsular tension ring;

fig. 2 schematically illustrates a prior art capsular tension ring;

fig. 3 schematically illustrates a plan view of a capsular tension ring according to the present invention;

fig. 4 schematically illustrates a perspective view of a capsular tension ring according to the present invention;

FIGS. 5a-5j schematically illustrate partial schematic views of capsular tension rings having different radii of curvature in accordance with the present invention;

FIGS. 6a-6g show the amount of deformation of a capsular tension ring according to the invention as a function of radius of curvature for different Young's moduli; and is

Fig. 7a-7e show the amount of deformation of a capsular tension ring according to the invention as a function of radius of curvature for different poisson's ratios.

Detailed Description

The present invention provides a capsular tension ring for easy and safe implantation having a smooth transition portion between the main body and the positioning portion of the capsular tension ring. The capsular tension ring of the invention can not only keep the integrity of the capsular bag, but also play a role in barrier and contact inhibition, prevent the proliferation and migration of lens epithelial cells and prevent the front capsular opacification and the back capsular opacification.

The transition between the main body and the positioning portion of the capsular tension ring of the present invention is smoother, with a smoothly transitioning curve from the positioning portion to the main body. When the bag tension ring is installed in the implanter, the stress of the bag tension ring is more uniform and dispersed, the stress concentration phenomenon is avoided, and the risk of fracture is reduced.

Fig. 3 schematically shows a plan view of a capsular tension ring according to the present invention. As shown in fig. 3, a capsular tension ring 100 in accordance with the present invention includes a generally annular body 110. The body 110 has a first end 114 and a second end 116. In some embodiments, the diameter D of the body 110 may be 11 mm to 15 mm, preferably 12 mm to 14 mm, and more preferably 12 mm to 13 mm. In some embodiments, the cross-section of the body 110 may be circular, rectangular, or polygonal. In some embodiments, for a body 110 that is circular in cross-section, the diameter of the cross-section may be 0.18 mm to 0.25 mm, preferably 0.20 mm to 0.24 mm, and more preferably 0.21 mm to 0.23 mm. The capsular tension ring 100 according to the present invention further includes a substantially circular first positioning portion 120 and a substantially circular second positioning portion 130. The first positioning portion 120 has a first positioning hole 122, and the second positioning portion 130 has a second positioning hole 132. The capsular tension ring 100 according to the present invention also includes a first transition portion 140 and a second transition portion 150. The first transition portion 140 forms a smooth transition between the first positioning portion 120 and the first end 114 of the main body 110, and the second transition portion 150 forms a smooth transition between the second positioning portion 130 and the second end 116 of the main body 110. The first and

second positioning portions

120 and 130 have outer diameter dimensions larger than the cross-sectional dimension of the main body 110. In some embodiments, as shown in fig. 3, the outer diameter dimensions of the first and

second positioning portions

120, 130 may be the same. Of course, the outer diameter sizes of the first positioning portion 120 and the second positioning portion 130 may also be different. The mechanical strength of the

positioning portions

120, 130 is related to the outer diameter dimension of the

positioning portions

120, 130 and the inner diameter dimension of the positioning holes 122, 132. On the one hand, the radial width of the positioning portions 120, 130 (i.e. half the difference between the outer diameter of the

positioning portions

120, 130 and the inner diameter of the positioning holes 122, 132) cannot be too small, otherwise the mechanical strength of the

positioning portions

120, 130 is insufficient. For example, the radial width of the

positioning portions

120, 130 should be above 0.15 mm. On the other hand, the inner diameter of the positioning holes 122, 132 cannot be too small. If the inner diameter of the positioning holes 122, 132 is too small, loading is difficult, and the wire required to hook the implanter is thin, which increases processing difficulty. For example, the inner diameter of the positioning holes 122, 132 should be greater than 0.3 mm. In some embodiments, the outer diameter d of the first and

second positioning portions

120, 130 may be 0.60 mm to 0.85 mm, preferably 0.65 mm to 0.75 mm, and more preferably 0.65 mm to 0.70 mm. The capsular tension ring 100 according to the present invention also includes a notch 112. The notch 112 is located between the first positioning portion 120 and the second positioning portion 130. The size of the gap affects the degree of compression of the capsular tension ring and the outward expansion force after compression. Too small a gap is not conducive to compression of the capsular tension ring, nor to outward expansion after compression. In some embodiments, the width W of the notch 112 may be 4 mm to 8mm, preferably 6mm to 8mm, and more preferably 6mm to 7 mm. As shown in fig. 3, the inner contour line of first transition portion 140 and/or second transition portion 150 may be a circular arc, as viewed in a direction perpendicular to the plane of capsular tension ring 100. Of course, the inner profile of first transition portion 140 and/or second transition portion 150 may be other shapes, such as parabolic, as viewed in a direction perpendicular to the plane of capsular tension ring 100. As used herein, "inner contour" refers to a contour that is located on the inner side (i.e., the side closer to the center of the generally annular body 110 of the capsular tension ring 100). As shown in fig. 3, the inside contours of the first transition portion 140 and the second transition portion 150 have the same radius of curvature R, as viewed in a direction perpendicular to the plane of the capsular tension ring 100. Of course, the radii of curvature of the inside contours of first transition portion 140 and second transition portion 150 may also be different as viewed in a direction perpendicular to the plane of capsular tension ring 100.

Fig. 4 schematically shows a perspective view of a capsular tension ring according to the present invention.

The results of the force analysis and simulation of the capsular tension ring according to the present invention are given below.

Currently clinically, the material used for the capsular tension ring is PMMA (polymethyl methacrylate) with a density of about 1.18 g/cm³The poisson ratio μ is about 0.32. For PMMA, the young's modulus E will be different for different processing methods. The young's modulus E of PMMA may be 3 GPa to 30 GPa.

The poisson's ratio of a material is constant, and different poisson's ratios represent different materials. In some embodiments of the present invention, capsular bag tension ring 100 is made of a material having a Poisson ratio of 0.2 to 0.4, preferably of a material having a Poisson ratio of 0.25 to 0.35, more preferably of a material having a Poisson ratio of 0.30 to 0.32.

In addition, the young's modulus E may also be different for different materials. In some embodiments of the invention, the capsular tension ring 100 is made of a material having a Young's modulus of 1 GPa to 30 GPa, preferably a material having a Young's modulus of 2 GPa to 20 GPa, more preferably a material having a Young's modulus of 3 GPa to 10 GPa, and even more preferably a material having a Young's modulus of 3 GPa to 5 GPa.

Fig. 5a-5j schematically illustrate partial schematic views of capsular tension rings having different radii of curvature R in accordance with the present invention.

And carrying out stress simulation on different curvature radiuses R. During loading or pushing out of the capsular tension ring, all cases are assumed to be subjected to 1N of force, then different curvature radiuses are respectively simulated on the basis of the force, and the point with the maximum deformation caused by the force is found. From the simulation results, no matter how the value of R is, the point where deformation is the largest when a force is applied (the position where fracture occurs first) is at a position close to the positioning portion.

Young's modulus E was set to 1 GPa and Poisson's ratio μ was set to 0.32. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in the graph shown in fig. 6 a.

Young's modulus E was set to 2 GPa and Poisson's ratio μ was set to 0.32. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 6 b.

Young's modulus E was set to 3 GPa and Poisson's ratio μ was set to 0.32. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 6 c.

Young's modulus E was set to 5 GPa and Poisson's ratio μ was set to 0.32. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 6 d.

Young's modulus E was set to 10 GPa and Poisson's ratio μ was set to 0.32. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 6 e.

The Young's modulus E was set to 20 GPa and the Poisson's ratio μ was set to 0.32. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 6 f.

The Young's modulus E was set to 30 GPa and the Poisson's ratio μ was set to 0.32. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 6 g.

Fig. 6a-6g each show a similar trend, i.e. the amount of deformation decreases as the radius of curvature increases, the amount of deformation being minimal at a radius of curvature of 2 mm to 2.5 mm and then increasing slowly as the radius of curvature increases.

The Poisson's ratio μ was set to 0.20, and the Young's modulus E was set to 3 GPa. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in the graph shown in fig. 7 a.

The Poisson's ratio μ was set to 0.25 and the Young's modulus E was set to 3 GPa. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 7 b.

The Poisson's ratio μ was set to 0.30 and the Young's modulus E was set to 3 GPa. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 7 c.

The Poisson's ratio μ was set to 0.35 and the Young's modulus E was set to 3 GPa. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 7 d.

The Poisson's ratio μ was set to 0.40 and the Young's modulus E was set to 3 GPa. Simulations were performed for the amount of deformation at different radii of curvature R, resulting in a graph as shown in fig. 7 e.

Figures 7a-7e all show a similar trend, i.e. the amount of deformation decreases as the radius of curvature increases, the amount of deformation being minimal at a radius of curvature of 2 mm to 2.5 mm and then increasing slowly as the radius of curvature increases.

As can be seen from fig. 6a-6g and fig. 7a-7e, the radius of curvature R of the inner contour of the first transition portion 140 and/or the second transition portion 150 may advantageously be 0.8mm to 5.0 mm, preferably 2.0 mm to 3.0 mm, more preferably 2.0 mm to 2.5 mm, viewed in a direction perpendicular to the plane of the capsular tension ring 100.

While the present invention has been described with reference to exemplary embodiment(s), it will be understood by those skilled in the art that the invention is not limited to the precise construction and components described herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims. The present invention is not limited by the illustrated ordering of steps, as some steps may occur in different orders and/or concurrently with other steps. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A pouch tension ring (100), the pouch tension ring (100) comprising:

a generally annular body (110), the body (110) having a first end (114) and a second end (116);

a first generally circular positioning portion (120), the first positioning portion (120) having a first positioning aperture (122);

a substantially circular second positioning portion (130), the second positioning portion (130) having a second positioning hole (132);

a first transition portion (140), the first transition portion (140) forming a smooth transition between the first positioning portion (120) and the first end (114);

a second transition portion (150), the second transition portion (150) forming a smooth transition between the second positioning portion (130) and the second end portion (116);

a notch (112), the notch (112) being located between the first positioning portion (120) and the second positioning portion (130);

wherein the first positioning portion (120) and the second positioning portion (130) have outer diameter dimensions larger than the cross-sectional dimension of the main body (110), and

wherein the radius of curvature of the inner profile line of the first transition portion (140) and/or the second transition portion (150) is 0.8mm to 5.0 mm, preferably 2.0 mm to 3.0 mm, more preferably 2.0 mm to 2.5 mm, as seen in a direction perpendicular to the plane of the capsular tension ring (100).

2. The capsular tension ring (100) of claim 1, wherein the diameter (D) of the body (110) is 11 mm to 15 mm, preferably 12 mm to 14 mm, more preferably 12 mm to 13 mm.

3. The capsular tension ring (100) of claim 1, wherein the cross-section of the body (110) is circular, rectangular or polygonal.

4. The capsular tension ring (100) of claim 1, wherein the cross-section of the body (110) is circular with a diameter of 0.18 mm to 0.25 mm, preferably 0.20 mm to 0.24 mm, more preferably 0.21 mm to 0.23 mm.

5. The capsular tension ring (100) of claim 1, wherein the width of the notch (112) is 4 mm to 8mm, preferably 6mm to 8mm, more preferably 6mm to 7 mm.

6. The capsular tension ring (100) of claim 1, wherein the outer diameter (d) of the first positioning portion (120) and the second positioning portion (130) is 0.60 mm to 0.85 mm, preferably 0.65 mm to 0.75 mm, more preferably 0.65 mm to 0.70 mm.

7. The capsular tension ring (100) of claim 1, wherein the capsular tension ring (100) is made of a material having a Poisson ratio of 0.2 to 0.4, preferably of a material having a Poisson ratio of 0.25 to 0.35, more preferably of a material having a Poisson ratio of 0.30 to 0.32.

8. The capsular tension ring (100) of claim 1, wherein the capsular tension ring (100) is made of a material having a young's modulus of 1 GPa to 30 GPa, preferably of a material having a young's modulus of 2 GPa to 20 GPa, more preferably of a material having a young's modulus of 3 GPa to 10 GPa, more preferably of a material having a young's modulus of 3 GPa to 5 GPa.

9. The capsular tension ring (100) of claim 1, wherein an inner contour of the first transition portion (140) and/or the second transition portion (150) is a circular arc or a parabola, viewed in a direction perpendicular to a plane in which the capsular tension ring (100) lies.