JPH0767896A - Intraocular lens - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an intraocular lens in which there is little risk of breakage of the support portion when inserted into the lens capsule, the position and direction of the lens body are stable, and insertion into the lens capsule is easy. . [Structure] The intraocular lens 2 has a lens body 4 made of polymethylmethacrylate and supporting portions 10A and 10B. The first portion 14 has the narrowest width, the second portion 16 gradually widens, and the third portion 18 has a substantially constant width, and each support 10
A and 10B have a smoothly continuous shape from the root 12 to the tip 20. With this structure, when the supporting portion 10A or 10B is deformed, the thinnest first portion 14 and the second portion 16 following the first portion 14 are mainly deformed. As a result, the first portion 14 that is most likely to break
And since the second portion 16 has sufficient deformability, the risk of breakage of the support portions 10A and 10B is extremely reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intraocular lens which is used by implanting it inside a lens capsule for the purpose of correcting visual acuity after extracting the lens during surgery for cataract or the like. In particular,
The present invention relates to a so-called single-piece type intraocular lens in which a lens body and a support part are integrally formed of the same material.

[0002]

2. Description of the Related Art An intraocular lens is used to correct the visual acuity after the crystalline lens has been removed in surgery for cataract or the like. This intraocular lens is used for the purpose of correcting visual acuity by incising an eyeball having a cataract or the like to remove and remove the contents of the lens, and then inserting the lens into the lens capsule to implant it. This intraocular lens has a lens main body that functions as an optical unit that focuses light on the retina instead of the crystalline lens, and a support unit that supports the lens main body in the capsular bag. The intraocular lens is supported at an appropriate position by bringing the support portion into contact with the inner wall of the lens capsule after the lens is extracted. In this way, the optical axis of the lens body is positioned so as to match the optical axis of the eyeball, and the intraocular lens is implanted in the lens capsule.

Such intraocular lenses are roughly classified into a three-piece type and a single-piece type. In a three-piece type intraocular lens, a lens body and a supporting portion are separately prepared and then fixed integrally. As a specific example, a small hole is provided in the lens body molded of methacrylic resin such as polymethylmethacrylate, and one end of the supporting portion made of polyvinylidene fluoride is inserted into this small hole, and the methacrylic resin around the small hole is inserted. Some of them are fixed by melting and solidifying. On the other hand, in the single-piece type intraocular lens, the lens main body and the support portion are integrally formed of the same material.
Compared to the above three-piece type, this single-piece type intraocular lens has the advantages that the manufacturing process is simple, mass production and automation are easy, and that the symmetry and equilibrium stability of each support part are excellent. Have.

However, in the case of the single piece type, the material of the supporting portion is uniquely determined depending on what is used as the material of the lens. In general, as a lens material, a methacrylic resin such as polymethylmethacrylate is often used because it has excellent strength, optical characteristics, biocompatibility, and little deterioration in vivo. However, these methacrylic resins are hard plastics, lack flexibility and are difficult to deform. As described above, the insertion of the intraocular lens into the lens capsule is performed by bending the support portion, and the elastic restoring force of the support portion holds the intraocular lens in the predetermined position inside the lens capsule in the predetermined orientation. Therefore, in the case of a supporting part made of methacrylic resin, which is poor in deformability, it is difficult to insert the lens into the lens capsule, and in extreme cases, the supporting part may even be broken. In particular, there is a high risk of breakage near the base of the support portion near the lens body.

In view of the above problems, various intraocular lenses have been devised in order to facilitate the deformation of the supporting portion made of a hard plastic material such as methacrylic resin having poor flexibility so that the supporting portion is not easily broken. Being developed.
As such an intraocular lens, for example, JP-A-4-3
There is an invention of an intraocular lens described in Japanese Patent Publication No. 09347. The technique described in this publication will be described with reference to FIG. FIG. 5 is a plan view showing the structure of an intraocular lens in the related art. As shown in FIG. 5, the intraocular lens 102 has a pair of supports 110A and 110B that symmetrically extend from the lens body 104. Lens body 104 and supporting portions 110A and 110B
Is made of polymethylmethacrylate and is integrally molded. These supporting portions 110A and 110B are connected to the lens body 104 by connecting portions 106A and 106B and the tip portion 12.
The area between 0A and 120B is 80% of the total length of the support.
It is narrow in the above range and has a substantially constant width. The ratio of the width to the thickness in this range is within the range of 0.5 to 1.0. With such a structure, the support portions 110A and 110B have flexibility with respect to an external force, and are easily deformed during the insertion operation into the lens capsule, so that the support portion is a single-piece type intraocular lens without breakage or the like.

[0006]

However, in the above-mentioned intraocular lens 102, the supporting portions 110A and 110 are used.
The width of B is narrow in the range of 80% or more of the total length, and when an external force is applied, the entire range bends, so that the support portion is excessively deformed. For this reason, there is a problem that the support portion is excessively bent during insertion into the lens capsule, the position and direction of the lens body are not stable, and the insertion operation is difficult. Therefore, in the present invention, there is no fear of breakage of the support portion during insertion into the lens capsule, and the position and direction of the lens body can be stabilized, and a single-piece intraocular lens that can be easily inserted into the lens capsule. The purpose is to provide.

[0007]

In order to solve the above problems, the present invention provides an intraocular lens having an optical part and a support part integrally extending from the optical part.
The support part has a root part connected to the optical part and a first part, a second part, a third part and a tip part which follow the root part, and the first part has the narrowest width in the support part. The width of the second portion gradually increases from the boundary with the first portion toward the boundary with the third portion,
The part has a constant width from the boundary with the second part to the boundary with the tip part that is substantially equal to the maximum width of the second part, and the total length of the first part and the second part. Created less than 50% of the total length of the support, creating an intraocular lens.

[0008]

The supporting portion of the intraocular lens of the present invention is
The first that is connected to the optical part and the root part and continues to this root part
It has a structure in which it becomes the thinnest in the region, becomes gradually thicker in the subsequent second region, and further extends to the tip portion with a constant width in the subsequent third region. The total length of the first portion and the second portion is less than 50% of the total length of the support portion. In the intraocular lens of the present invention having such a structure, when it is inserted into the lens capsule during transplantation, the optical part is grasped and one support part and the optical part are inserted. The remaining support is then grasped and inserted into the capsule. At this time, since the first part and the second part that are most likely to be broken or the like have sufficient deformability, the risk of breakage of the support portion is extremely reduced. Also, 50% of the total length of the support part
The first part and the second part having a length of less than 1 are mainly deformed, and the other parts are less deformed, so that the entire supporting part does not excessively bend and has sufficient shape retention in the lens capsule. Upon insertion, the optical part can be surely positioned and oriented within the lens capsule, and the insertion operation becomes easy. In this way, there is little risk of breakage of the support part when it is inserted into the lens capsule,
In addition, the position and direction of the lens body can be stabilized, and the single-piece type intraocular lens can be easily inserted into the lens capsule.

[0009]

【Example】

Example 1 Next, Example 1 embodying the present invention will be described with reference to FIGS. 1, 2, 4 and Table 1. FIG. 1 is a plan view and a side view showing the overall structure of Example 1 of the intraocular lens according to the present invention. Further, FIG. 2 is a plan view showing the dimensions of each part of the intraocular lens of the first embodiment. As shown in FIG. 1, the intraocular lens 2 of the present embodiment has a structure in which a pair of curved support parts 10A and 10B extend from opposite positions of the lens body 4. Lens body 4 and support 1
The material of 0A and 10B is polymethylmethacrylate. As shown in FIG. 1B, the supporting portion 10
A and 10B are provided at an angle of 10 degrees with respect to the center plane of the lens. The diameter D of the lens body 4 is 6.3 mm as described later.

The lens body 4 is provided with a pair of positioning holes 6A and 6B. These positioning holes 6A and 6B are holes for hooking the tip of a sharp jig in order to adjust the position and orientation of the lens body 4 after inserting the intraocular lens 2 into the lens capsule. In the intraocular lens 2 of the present embodiment, two positioning holes are provided at symmetrical positions on the periphery of the lens body 4, but one, three, or four positioning holes may be provided, and the positioning holes may be provided. Some are not. The intraocular lens 2 is manufactured by cutting out from a block of polymethylmethacrylate using an NC (numerical control) lathe or molding, and the manufacturing procedure of these is a known technique. The description is omitted.

Each of the supporting portions 10A and 10B has a root portion 12, a first portion 14, a second portion 16, a third portion 18,
And a tip portion 20. The root portion 12 is a portion where the lens body 4 and the supporting portions 10A and 10B are connected to each other, and is a portion whose width is sharply narrowed from the peripheral edge portion of the lens body 4. The first portion 14 has a substantially constant width that is equal to the width of the terminal end of the root portion 12. The first portion 14 is a portion having the smallest width in the support portions 10A and 10B. The second portion 16 has a structure that starts from a width equal to the width of the terminal end of the first portion 14 and gradually widens with increasing distance from the lens body 4. Further, the third portion 18 has a uniform width equal to the width of the terminal end of the second portion 16. Then, the third portion 18 extends to the tip portion 20 with a uniform width, but at the tip portion 20, the width is increased and has a swollen shape. In this way
Each of the support portions 10A and 10B includes a root portion 12 to a tip portion 20.
It has a smooth continuous shape.

Here, the length a of the root portion 12 is 0.2 to
It is preferably within the range of 0.8 mm. Also, the first
The length b of the portion 14 is preferably within the range of 0.01 to 2.0 mm. The total length (b + c) of the first portion 14 and the second portion 16 is made to be less than 50% of the total length (a + b + c + d) of the support portion 10A. The width of the first portion 14 is 0.06 to 0.14.
It is preferably within the range of mm. Further, the width of the second portion 16 is preferably in the range of 0.06 to 0.24 mm, and the width of the third portion 18 is 0.14 to 0.24 m.
It is preferably within the range of m.

Next, specific dimensions of each part of the intraocular lens 2 of this embodiment will be described with reference to FIG. In the intraocular lens 2 of the present embodiment, the lens body 4 has a circular shape with a diameter of 6.3 mm, and the supporting portions 10A, 10 in the unloaded state
The distance between the most distant portions of B (that is, the diameter of the circle indicated by the chain double-dashed line in FIG. 2) is 12.5 mm. Each part of the support part 10 of the intraocular lens 2 has dimensions as shown in FIG. That is, the width of the first portion 14 is substantially constant and is 0.12 mm, and the width of the second portion 16 is 0.12 mm.
To 0.16 mm. Also, the third part 1
The width of 8 is almost constant and is 0.16 mm. The total length of the first part 14 and the second part 16 is about 2 mm.
And is about 25% of the total length of the support portion. Also,
The thicknesses of the first portion 14, the second portion 16, and the third portion 18 are all 0.16 mm and have a uniform thickness.
These dimensions are summarized in Table 1.

[0014]

[Table 1]

Now, the characteristics of the intraocular lens 2 having such a structure will be described with reference to FIG. 4 and Table 1.
The basic characteristics of the supporting portions 10A and 10B of the intraocular lens 2 are as follows: a pulling distance until breakage when an external force is applied to one point of the supporting portion and a constant length when the supporting portions 10A and 10B are sandwiched and compressed. The load was checked. Here, a tensile test device for examining the deformation distance of the support portion will be described with reference to FIG. FIG. 4 shows the support portion 10 of the intraocular lens 2.
It is a front view which shows the test apparatus for the tensile test of A and 10B. As shown in FIG. 4, this tensile test device 3
0 is composed mainly of a device body 40 having a Y-shaped upper part, and a tensile tester 32 provided above the device body 40 for applying a tensile force to the sample. Inside the device body 40, a pair of holding discs 48A and 48B are provided. Female screws are provided on these holding discs 48A and 48B.
It is screwed into a pair of male screw parts 46A and 46B provided inside 0.

The mounting of the test piece on the apparatus main body 40 is
It is performed as follows. First, the lens body 4 of the intraocular lens 2, which is the sample, is attached to the lens fixing jig 50 with an adhesive. Next, this lens fixing jig 50
However, the attached intraocular lens 2 is placed between the pair of holding discs 48A and 48B so that the intraocular lens 2 is oriented as shown in FIG. Then, the lens fixing jig 50 is sandwiched between the holding discs 48A and 48B by screwing the holding discs 48A and 48B in opposite directions. Next, the pull rod 34 is attached to the one support portion 10A of the intraocular lens 2 fixed in this way. As shown in FIG. 4, a gap 36 for mounting the support portion is provided at the tip of the pulling rod 34, and the support portion 10A is passed through the mounting gap 36 and fixed by crimping. The pull rod 34 attached to the support portion 10A in this manner
Is fixed to a chuck mechanism (not shown) at the lower end of the tensile tester 32.

Further, in this embodiment, in order to make the condition close to the actual use condition, the test is conducted in a liquid (BSS) having a composition close to aqueous humor filled in the eyeball. That is,
Water-resistant transparent tape 42 (only the front side is shown in FIG. 4) is attached to both surfaces of the device body 40, and the inside of the device body 40 is filled with a liquid (BSS) having a composition close to aqueous humor. Now, after the intraocular lens specimen is set in this way, a tensile test is carried out. Pulling rod 34 to 50 m / m
The tensile distance when the supporting portion 10A is broken is measured by continuously moving at a speed of in. In this way, 2
When the tensile distance until breakage (hereinafter, referred to as "breakage distance") was measured for 0 supporting portions, the average value was 6.8 mm, which was a preferable breakage resistance. Separately, 2m for 5 support parts
When the load during m compression was measured, the average value was 370 mgf, which was a preferable value.

On the other hand, as Comparative Example 1, an intraocular lens having the same structure as in Example 1 was prepared except that the width of the supporting portion was 0.16 mm over the entire length, and the same method was used. The breaking distance and the load when compressed by 2 mm were measured. As a result, as shown in Table 1, the breaking distance was 5.8 mm.
It was found to be short and inferior in flexibility. Further, the load when compressed by 2 mm was 720 mgf, which was a little hard. In addition, as Comparative Example 2, an intraocular lens having the same structure as that of Example 1 was prepared except that the width of the supporting portion was 0.10 mm over the entire length and the thickness of the supporting portion was 0.14 mm. Then, the characteristics were measured in the same manner. As a result, as shown in Table 1, it was found that the breaking distance was as long as 8.6 mm and the bending resistance was excellent, but the load when compressed at 2 mm was 160 mgf, which was too soft. Therefore, when an insertion test into the lens capsule was performed using a pig's eye, the position of the optical part was not stable because the support part was too soft, and the insertion operation was difficult. As described above, according to the intraocular lens 2 of Example 1, preferable characteristics of the supporting portion can be obtained, whereas in the case of the comparative example in which the width of each portion of the supporting portion is constant, neither is preferable. It turned out that the result was obtained.

Second Embodiment Next, a second embodiment embodying the present invention will be described mainly with reference to FIG. 3 and Table 1. Also in the intraocular lens of the present embodiment, the lens body and the supporting portion are made of polymethylmethacrylate, and have the same overall structure as the intraocular lens 2 of the embodiment 1 shown in FIG. Next, specific dimensions of each part of the intraocular lens 52 of the present embodiment will be described with reference to FIG. The intraocular lens 52 of this embodiment is
As shown in FIG. 3, the lens body 54 has a diameter D of 5.
It is 5 mm and is different from Example 1 in that a positioning hole is not provided. The distance between the furthest portions of the supporting portions 60A and 60B in the unloaded state is 12.5 mm, which is the same as in the first embodiment. Each part of the support part 60 of the intraocular lens 52 has dimensions as shown in FIG. That is, the width of the first portion 64 is substantially constant and is 0.12 mm, and the width of the second portion 66 is 0.12 mm.
It extends from mm to 0.16 mm. The width of the third portion 68 is substantially constant and is 0.16 mm. The total length of the first portion 64 and the second portion 66 is about 2 mm, which is about 25% of the total length of the support portion. Also,
The thicknesses of the first portion 64, the second portion 66, and the third portion 68 are all 0.16 mm and have a uniform thickness.
These dimensions are summarized in Table 1.

With respect to the intraocular lens 52 having such a structure, the breaking distance for 20 supporting portions and the load at the time of 2 mm compression for 5 supporting portions were measured in the same manner as in Example 1. As a result, as shown in Table 1, the average value of the 20 breaking distances was 6.7 mm, which was a preferable break resistance. Also, 2 mm
The average value of the five loads during compression was 440 mgf, which was a preferable value.

On the other hand, as Comparative Example 3, an intraocular lens having the same structure as the intraocular lens 52 of Example 2 was prepared except that the width of the supporting portion was 0.16 mm over the entire length. The characteristics were measured in the same manner. As a result, as shown in Table 1, it was found that the breaking distance was as short as 5.1 mm, which was unfavorable for breaking. Further, the load when compressed by 2 mm was 960 mgf, which was a little hard. As described above, according to the intraocular lens 52 of Example 2, preferable characteristics of the supporting portion can be obtained, whereas in the case of the comparative example in which the width of each portion of the supporting portion is constant, unfavorable results are obtained. It turned out to be obtained.

In each of the above embodiments, the case of the intraocular lens having the pair of supporting portions has been described, but the present invention is not limited by the number of supporting portions. Further, the material of the intraocular lens may be a hard material other than polymethylmethacrylate. The structure, shape, size, number, disposition, etc. of the portion other than the supporting portion of the intraocular lens are not limited to those in the above-described embodiments.

[0023]

According to the present invention, the support portion has a length of less than 50% of its total length, which is narrowed from the root portion with the optical portion and then gradually thickened, and then extends to the tip portion with a constant width. Since the intraocular lens having the above is created, the supporting portion is less likely to be broken when it is inserted into the lens capsule, and the position and direction of the lens body can be stabilized, so that the lens body can be easily inserted into the lens capsule. by this,
It is a practical intraocular lens that is not likely to be damaged during the implantation operation into the lens capsule and that allows smooth insertion.

[Brief description of drawings]

FIG. 1 is a plan view and a side view showing an overall structure of Examples 1 and 2 of an intraocular lens according to the present invention.

FIG. 2 is a plan view showing the structure of each part of Example 1 of the intraocular lens.

FIG. 3 is a plan view showing the structure of each part of Example 2 of the intraocular lens.

FIG. 4 is a front view showing a test apparatus for a tensile test of a support portion in Examples 1 and 2 of the intraocular lens.

FIG. 5 is a plan view showing the overall configuration of a conventional intraocular lens.

[Explanation of symbols]

 2 Intraocular lens 4 Optical part 10A, 10B Support part 12 Root part 14 1st site | part 16 2nd site | part 18 3rd site | part 20 Tip part

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[Procedure amendment]

[Submission date] September 16, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

Such intraocular lenses are roughly classified into a three-piece type and a single-piece type. In the three-piece type intraocular lens, the lens main body and the support portion are separately manufactured, and then fixed integrally. As a specific example, a small hole is provided in the lens body molded of methacrylic resin such as polymethylmethacrylate, and one end of the supporting portion made of polyvinylidene fluoride is inserted into this small hole, and the methacrylic resin around the small hole is inserted. Some of them are fixed by melting and solidifying. On the other hand, in the single-piece type intraocular lens, the lens main body and the support portion are integrally formed of the same material.
Compared to the above three-piece type, this single-piece type intraocular lens has the advantages that the manufacturing process is simple, mass production and automation are easy, and that the symmetry and equilibrium stability of each support part are excellent. Have.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

However, in the above-mentioned intraocular lens 102, the supporting portions 110A and 110 are used.
The width of B is narrow in the range of 80% or more of the total length, and when an external force is applied, the entire range bends, so that the support portion is excessively deformed. For this reason, there is a problem that the support portion is excessively bent during insertion into the lens capsule, the position and direction of the lens body are not stable, and the insertion operation is difficult. Therefore, in the present invention, the risk of breakage of the support portion during insertion into the lens capsule is small, and the position and direction of the lens body can be stabilized, and the single-piece intraocular lens that is easy to insert into the lens capsule. The purpose is to provide.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

The supporting portion of the intraocular lens of the present invention is
The first that is connected to the optical part and the root part and continues to this root part
It has a structure in which it becomes the thinnest in the region, becomes gradually thicker in the subsequent second region, and further extends to the tip portion with a constant width in the subsequent third region. The total length of the first portion and the second portion is less than 50% of the total length of the support portion. In the intraocular lens of the present invention having such a structure, when it is inserted into the lens capsule during transplantation, the optical part is grasped and one support part and the optical part are inserted. The remaining support is then grasped and inserted into the capsule. At this time, since the first part and the second part that are most likely to be broken or the like have sufficient deformability, the risk of breakage of the support portion is extremely reduced. Also, 50% of the total length of the support part
The first part and the second part having a length of less than 1 are mainly deformed, and the other parts are less deformed, so that the entire supporting part does not excessively bend and has sufficient shape retention in the lens capsule. Therefore, at the time of insertion, the optical part can be surely positioned and oriented in the lens capsule, and the insertion operation becomes easy. In this way, a single-piece intraocular lens with less risk of breakage of the support portion when inserted into the lens capsule, and in which the position and direction of the lens body can be stabilized and which can be easily inserted into the lens capsule. Becomes

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

The mounting of the test piece on the apparatus main body 40 is
It is performed as follows. First, the lens body 4 of the intraocular lens 2, which is the sample, is attached to the lens fixing jig 50 with an adhesive. Next, this lens fixing jig 50
However, the attached intraocular lens 2 is placed between the pair of holding discs 48A and 48B so that the intraocular lens 2 is oriented as shown in FIG. Then, the lens fixing jig 50 is sandwiched between the holding discs 48A and 48B by screwing the holding discs 48A and 48B in opposite directions. Next, the pull rod 34 is attached to the one support portion 10A of the intraocular lens 2 fixed in this way. As shown in FIG. 4, a gap 36 for mounting the support portion is provided at the tip of the pulling rod 34, and the support portion 10A is passed through the mounting gap 36 and fixed by crimping. The pull rod 34 attached to the support portion 10A in this manner
Is fixed to a chuck mechanism (not shown) at the lower end of the tensile tester 32.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Further, in this embodiment, in order to make the condition close to the actual use condition, the test is conducted in a liquid (BSS) having a composition close to aqueous humor filled in the eyeball. That is,
Water-resistant transparent tape 42 (only the front side is shown in FIG. 4) is attached to both surfaces of the device body 40, and the inside of the device body 40 is filled with a liquid (BSS) having a composition close to aqueous humor. Now, after the intraocular lens specimen is set in this way, a tensile test is carried out. 50 mm / pull rod 34
The tensile distance is measured when the supporting portion 10A is broken by continuously moving at a speed of min. In this way
The tensile distance until breakage (hereinafter referred to as "breakage distance") of 20 support portions was measured, and the average value was 6.8 mm, which was a preferable breakage resistance. Separately, 2m for 5 support parts
When the load during m compression was measured, the average value was 370 mgf, which was a preferable value.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chizuruko Mano 2-22-14 Noritake Shinmachi, Nishi-ku, Nagoya, Aichi Prefecture Menicon Distribution Center Building (72) Inventor Yoshiharu Yamada 2-22, Noritake Shinmachi, Nishi-ku, Aichi Prefecture No. 14 Inside Menicon Distribution Center Building

Claims (1)

[Claims] 1. An intraocular lens having an optical part and a support part integrally extending from the optical part, wherein the support part is a root part connected to the optical part and a first part and a second part following the root part. , A third portion and a tip portion, the first portion has the narrowest width in the support portion, and the width of the second portion is the third from the boundary with the first portion.
The third portion gradually expands toward the boundary with the portion, and the third portion has a constant width substantially equal to the maximum width of the second portion from the boundary with the second portion to the boundary with the tip portion. The intraocular lens, wherein the total length of the first part and the second part is less than 50% of the total length of the support part.