Intraocular lens material and intraocular lens

Abstract

One embodiment of the present invention provides an intraocular lens material. The intraocular lens material contains: a mono(meth)acrylate (A) that has an aryl group in the molecular structure thereof; a mono(meth)acrylate (B) that is different from the mono(meth)acrylate (A) and that has an aryl group in the molecular structure thereof; and a di(meth)acrylate (C) that has an alkylene oxide group in the molecular structure thereof. The content of the mono(meth)acrylate (A) in the intraocular lens material is 45-70 mol%, and the total content of the mono(meth)acrylate (A) and the mono(meth)acrylate (B) is 85 mol% or more. The proportion of the di(meth)acrylate represented by general formula (I) in the di(meth)acrylate (C) is 60 mol% or more. [In the formula, X is a methyl group or a hydrogen atom, and n is an integer of 12-30.]

Description

Intraocular lens materials and intraocular lenses

[0001] The present invention relates to an intraocular lens material and an intraocular lens. More specifically, the present invention relates to an intraocular lens material that can be used to produce an intraocular lens that has a high refractive index, sufficient flexibility and elongation to allow the lens to be folded into a small size, and reduced occurrence of glistening and whitening, and an intraocular lens that has a high compressive load of the haptics despite the optic and haptics being made of the same material.

[0002] With the spread of phacoemulsification and aspiration surgery, soft intraocular lenses that can be inserted through small incisions have been developed and are now widely used in clinical practice, with the aim of reducing postoperative astigmatism and surgical invasiveness. While traditionally, intraocular lenses were limited to single-focus lenses that focused on either near or far objects, multifocal intraocular lenses that correct both near and far vision and toric intraocular lenses that correct preoperative astigmatism have recently been developed and commercialized.

[0003] An intraocular lens comprises an optical portion that corrects a patient's vision and haptics that hold the optical portion in place within the eye. Such an intraocular lens is folded into a small size for insertion into the lens capsule through a corneal incision and placed in the appropriate position within the lens capsule. The folded intraocular lens then unfolds so that the haptics contact the lens capsule and are held within the capsule by the haptics. The intraocular lens material used to form such an intraocular lens must have a high refractive index so that the thickness of the intraocular lens can be reduced. Furthermore, the intraocular lens is rolled or folded into a small size for insertion into the eye through a small incision. To prevent cracking or breakage during this process, the intraocular lens material must also be flexible and have a high elongation rate.

[0004] Next, after the intraocular lens is inserted into the eye, the intraocular lens material must not suffer from glistening or whitening, a phenomenon in which water trapped in the lens precipitates and aggregates, resulting in significant loss of transparency. Furthermore, even if the haptics or contact areas within the lens capsule shrink after surgery, the optical part of the lens rarely shifts significantly, but some decentration or tilt may occur over time. Multifocal and toric intraocular lenses, in particular, must be inserted and fixed correctly in the desired position both during and after surgery, and it is important that the intraocular lens is highly stable and does not rotate within the lens capsule.

[0005] Here, intraocular lenses made of flexible materials are classified into two types: a three-piece type in which loop-shaped wires made of PMMA (polymethyl methacrylate), PP (polypropylene), or PVDF (polyvinylidene fluoride) are attached as haptics to an optical portion made of a transparent and flexible acrylic material; and a one-piece type in which the optical portion and haptics are integrated using the same material. Three-piece intraocular lenses have the advantage that the haptics are made of a material that is harder and more elastic than the optical portion, resulting in higher stress during compression and therefore higher stability within the lens capsule. However, due to the thin loops of the haptics, they are unable to fully absorb external forces acting on the intraocular lens when the lens capsule contracts, which can lead to rotation of the optical portion and, depending on the orientation of the hard and highly elastic haptics (loops), can damage the lens capsule when inserted into the lens capsule.

[0006] On the other hand, one-piece intraocular lenses not only facilitate insertion into the lens capsule due to their structure, but also eliminate the risk of damaging the lens capsule due to the high flexibility of their haptics. Furthermore, the haptics of one-piece lenses can be made wider than those of three-piece lenses, making the optical part less likely to rotate after surgery. However, one-piece intraocular lenses tend to be less stable within the lens capsule than three-piece intraocular lenses because their haptics are soft and experience lower stress when compressed. To improve the stability of one-piece intraocular lenses within the lens capsule, it is sufficient to increase the force with which the haptics press against the ocular tissue. It has been proposed to construct the haptics from a main body made of a flexible material and a stem made of an elastic material (see Patent Document 1). However, in Patent Document 1, the stem is embedded within the main body, which constitutes the haptics, requiring precise alignment and fixation of the stem in the appropriate location, resulting in a complex process that is not suitable for mass production.

[0007] Patent Document 2 proposes a polymer material and an intraocular lens containing a four-branched macromonomer containing a repeating unit of an ethylene oxide group. The four-branched macromonomer containing a repeating unit of an ethylene oxide group is used to suppress glistening and whitening. However, because this component also serves as a crosslinking agent, the number of crosslinking points in the network polymer increases, which tends to reduce the elongation of the resulting polymer material. Furthermore, in the examples, a relatively large amount of methacrylate monomers having aryl groups is blended among the components constituting the polymer material, but no consideration is given to the relationship between the type and amount of these components and the compressive load of the support of the intraocular lens.

[0008] JP 2018-183197 A JP 2019-210345 A

[0009] In view of the above circumstances, the object of the present invention is to provide an intraocular lens material that can be used to produce an intraocular lens that has a high refractive index, sufficient flexibility and elongation to allow the lens to be folded into a small size, and that suppresses the occurrence of glistening and whitening, and an intraocular lens that has a high compressive load on the haptics and is highly stable within the eye, even though the optical part and haptics are made of the same material.

[0010] According to one aspect of the present invention, there is provided an intraocular lens material. The intraocular lens material includes a mono(meth)acrylate (A) having an aryl group in its molecular structure, a mono(meth)acrylate (B) different from the mono(meth)acrylate (A) and having an aryl group in its molecular structure, and a di(meth)acrylate (C) having an alkylene oxide group in its molecular structure. The content of the mono(meth)acrylate (A) in the intraocular lens material is 45 mol % to 70 mol %, and the total content of the mono(meth)acrylate (A) and the mono(meth)acrylate (B) is 85 mol % or more. The proportion of the di(meth)acrylate represented by the following general formula (I) in the di(meth)acrylate (C) is 60 mol % or more. [In the formula, X is a methyl group or a hydrogen atom, and n is an integer of 12 or more and 30 or less.]

[0011] According to this aspect, it is possible to provide an intraocular lens material that can be used to produce an intraocular lens that has a high refractive index, sufficient flexibility and elongation to allow the lens to be folded small, and that suppresses the occurrence of glistening and whitening, as well as an intraocular lens that has a high compressive load on the haptics and is highly stable within the eye, even though the optical part and haptics are made of the same material.

[0012] FIG. 1 is a plan view showing the configuration of an intraocular lens. FIG. 2 is a view showing a state in which an intraocular lens is set on the stage of a haptic compression load measuring device. FIG. 3 is a view showing a state in which the distance between haptics of the intraocular lens is compressed to 10 mm. FIG. 4 is a view showing a state in which the optical portion of the intraocular lens is set on a stage for measuring the compression load of the optical portion. FIG. 5 is a view showing a state in which the optical portion of the intraocular lens is compressed to 3 mm and folded in half. FIG. 6 is a graph showing the relationship between the distance (compression distance) between haptics and compression load in Examples 1 to 3 and Comparative Examples 1 and 2. FIG. 7 is a plan view showing another configuration of an intraocular lens.

[0013] The intraocular lens material and intraocular lens of the present invention are described in detail below. <<Intraocular Lens Material>> The intraocular lens material is a composition that can be used to prepare an intraocular lens. Here, the intraocular lens comprises an optical portion that transmits light and a pair of haptics that protrude outward from opposite positions on the optical portion and support (hold) the optical portion within the eye.

[0014] This intraocular lens material includes a mono(meth)acrylate (A) having an aryl group in its molecular structure (hereinafter also referred to simply as "mono(meth)acrylate (A)"), a mono(meth)acrylate (B) which is different from the mono(meth)acrylate (A) and has an aryl group in its molecular structure (hereinafter also referred to simply as "mono(meth)acrylate (B)"), and a di(meth)acrylate (C) having an alkylene oxide group in its molecular structure (hereinafter also referred to simply as "di(meth)acrylate (C)").

[0015] This intraocular lens material is a mixed solution of monomers, namely, mono(meth)acrylate (A), mono(meth)acrylate (B), and di(meth)acrylate (C). Therefore, hereinafter, the intraocular lens material will also be referred to as a "monomer mixed solution." Furthermore, the monomer mixed solution may further contain optional additives, such as a crosslinkable monomer, a reactive monomer having ultraviolet absorption properties, or a reactive monomer having coloring properties, as needed. Each component will be explained below in turn.

[0016] <Mono(meth)acrylate (A)> Mono(meth)acrylate (A) is a monomer blended into the monomer mixture for the purposes of imparting a sufficient elastic modulus to the intraocular lens and enabling the haptics to withstand a high compressive load. When a homopolymer is synthesized using mono(meth)acrylate (A), the glass transition temperature of the homopolymer of mono(meth)acrylate (A) is preferably higher than the glass transition temperature of the homopolymer of mono(meth)acrylate (B), which will be described later. When an intraocular lens material contains mono(meth)acrylates (A) and (B) with different properties, the glass transition temperature of the copolymer (hereinafter simply referred to as the "obtained copolymer") obtained by polymerization of the intraocular lens material can be appropriately adjusted by appropriately setting the ratio of their amounts. As a result, the elastic modulus of the intraocular lens can be sufficiently increased.

[0017] The glass transition temperature of the homopolymer of the mono(meth)acrylate (A) is preferably about 40°C or higher, and more preferably about 40°C or higher and 70°C or lower. In this case, the glass transition temperature of the resulting copolymer can be more appropriately adjusted. The mono(meth)acrylate (A) is preferably a compound having one aryl group and one (meth)acryloyl group in one molecule. Herein, the term "(meth)acryloyl group" means a methacryloyl group or an acryloyl group.

[0018] Specific examples of the mono(meth)acrylate (A) include 2-phenylethyl methacrylate, 2-phenoxyethyl methacrylate, benzyl methacrylate, and phenyl acrylate. Among these, 2-phenylethyl methacrylate, 2-phenoxyethyl methacrylate, and benzyl methacrylate are preferred as the mono(meth)acrylate (A). These compounds may be used alone or in combination of two or more. Use of such a mono(meth)acrylate (A) makes it easier to increase the glass transition temperature of the resulting copolymer.

[0019] The content of the mono(meth)acrylate (A) in the intraocular lens material is about 45 mol% to 70 mol%, more preferably about 50 mol% to 70 mol%, and even more preferably about 50 mol% to 68 mol%. When the content is expressed in mass%, the content of the mono(meth)acrylate (A) in the intraocular lens material is preferably about 40 mol% to 60 mol%, more preferably about 42 mol% to 60 mol%, and even more preferably about 45 mol% to 60 mol%. In this case, the elastic modulus of the intraocular lens is further increased, and the compressive load of the haptics can be further increased.

[0020] In this specification, "glass transition temperature (Tg)" refers to a value determined by differential scanning calorimetry, which will be described later. Furthermore, "mol %" refers to the number of moles of a given component relative to the total amount (100 mol %) of the mono(meth)acrylate (A), the mono(meth)acrylate (B), the di(meth)acrylate (C), the crosslinkable monomer (D), the reactive monomer (E) having UV absorption properties, the reactive monomer (F) having colorability, and the (meth)acrylate (H) having an ethylene oxide group. Similarly, "mass %" refers to the mass of a given component relative to the total amount (100 mass %) of the masses of these components ((A) to (F) and (H)).

[0021] <Mono(meth)acrylate (B)> The mono(meth)acrylate (B) is a monomer that is blended into the monomer mixture together with the mono(meth)acrylate (A) for the purpose of imparting a high refractive index to the intraocular lens. The mono(meth)acrylate (B) is also a monomer used to adjust the glass transition temperature of the resulting copolymer. The glass transition temperature of a homopolymer of the mono(meth)acrylate (B) is preferably less than about 40°C, more preferably about 30°C or less, and even more preferably about 20°C or less. The glass transition temperature is preferably about −5°C or higher. The use of such a mono(meth)acrylate (B) allows for more appropriate adjustment of the glass transition temperature of the resulting copolymer. The mono(meth)acrylate (B) is preferably a compound having one or two aryl groups and one (meth)acryloyl group in one molecule.

[0022] Specific examples of the mono(meth)acrylate (B) include 2-phenylethyl acrylate, 3-phenylpropyl (meth)acrylate, 4-phenylbutyl (meth)acrylate, 2-phenoxyethyl acrylate, 3-phenoxypropyl (meth)acrylate, 4-phenoxybutyl (meth)acrylate, benzyl acrylate, 3-phenoxybenzyl (meth)acrylate, 5-phenylpentyl (meth)acrylate, 6-phenylhexyl (meth)acrylate, 5-phenoxypentyl (meth)acrylate, and 6-phenoxyhexyl (meth)acrylate. Among these, preferred mono(meth)acrylates (B) are 2-phenylethyl acrylate, 3-phenylpropyl methacrylate, 4-phenylbutyl methacrylate, 2-phenoxyethyl acrylate, and 3-phenoxybenzyl methacrylate. These compounds may be used alone or in combination of two or more. By using such a mono(meth)acrylate (B), it is easy to adjust the glass transition temperature of the resulting copolymer.

[0023] The total content of mono(meth)acrylate (A) and mono(meth)acrylate (B) in the intraocular lens material is about 85 mol% or more, more preferably about 90 mol% or more, and even more preferably about 95 mol% or more. When the content is expressed in mass%, the total content of mono(meth)acrylate (A) and mono(meth)acrylate (B) in the intraocular lens material is preferably about 80 mass% or more, more preferably about 82 mass% or more, and even more preferably about 85 mass% or more. By setting the content of mono(meth)acrylate (A) and mono(meth)acrylate (B) within the above ranges, it is possible to suitably adjust the glass transition temperature of the resulting copolymer, and also to increase the refractive index of the intraocular lens while imparting flexibility that allows the intraocular lens to be folded compactly.

[0024] As described above, an intraocular lens has an optical portion that corrects vision and haptics that hold the optical portion within the eye. An intraocular lens inserted into the eye is held in the lens capsule by the haptics expanding to contact the lens capsule. Therefore, to obtain an intraocular lens with high intraocular stability, it is important to increase the force with which the haptics press against the lens capsule (i.e., the repulsive force of the haptics). While the detailed mechanism is unclear, it has been revealed that the compressive load of the haptics can be increased by using a certain amount of the mono(meth)acrylate (A). It is believed that the physical properties of copolymers synthesized by radical polymerization are affected by the selection and amount of monomers constituting the copolymer, as well as the network polymer structure. Therefore, rather than a single physical property, it is believed that the compressive load of the haptics ultimately increases due to the interaction of physical properties such as the copolymer's glass transition temperature, mechanical strength, elongation, and stress.

[0025] <Di(meth)acrylate (C)> Di(meth)acrylate (C) is a monomer that is blended into the monomer mixture liquid for the purposes of not only suppressing the occurrence of glistening and whitening of the intraocular lens but also imparting to the intraocular lens sufficient flexibility and elongation for compact folding, etc. This di(meth)acrylate (C) is a monomer or macromonomer having a repeating unit of an alkylene oxide group and two (meth)acryloyl groups in its molecular structure, as represented by the following general formula: [In the formula, X is a methyl group or a hydrogen atom, R is an alkylene group, and l is an integer of 12 or more and 40 or less.]

[0026] In the above general formula, the value of l may or may not have a distribution. The absence of a distribution in the value of l means, for example, that when the value of l is 12, it is a single repeat number that does not include other values ​​(10, 11, 13, etc.). The repeat number l of the alkylene oxide group is preferably an integer of 12 to 38, more preferably an integer of 12 to 36. Setting l to a value equal to or greater than the above lower limit more reliably suppresses the occurrence of glistening and whitening in the intraocular lens and provides excellent flexibility and elongation for compact folding of the intraocular lens. Setting l to a value equal to or less than the above upper limit, on the other hand, enhances compatibility with other monomers (A, B, D, E, F, and H), enabling the production of a homogeneous monomer mixture (intraocular lens material).

[0027] In this specification, the term "average value" applies when there is a distribution in the number of repeats in the alkylene oxide group of the di(meth)acrylate (C) and the ethylene oxide group of the (meth)acrylate (H) having an ethylene oxide group other than the di(meth)acrylate (C) described later. Specifically, the term "average value" applies when there is a distribution in the number of repeats in the alkylene oxide group of the di(meth)acrylate (C) or the (meth)acrylate (H) described later. １ The repeat number is calculated using the peak integrated intensity ratio of alkylene oxide or ethylene oxide by H-NMR analysis, and the value is rounded off to one decimal place.

[0028] Examples of di(meth)acrylates (C) include di(meth)acrylates having a molecular weight of approximately 600 or more and 2,400 or less. In the present specification, "molecular weight" refers to the number-average molecular weight calculated by gel permeation chromatography in the case of di(meth)acrylate (C) or (meth)acrylate (H). In the present specification, "macromonomer" refers to a monomer having a molecular weight of 800 or more. If the molecular structure of this di(meth)acrylate (C) is monofunctional, the elongation of the resulting copolymer becomes excessively large, which is undesirable because it results in poor shape recovery of the intraocular lens and, depending on the amount added, makes it impossible to suppress glistening or whitening. Furthermore, if the di(meth)acrylate (C) is trifunctional or more, the number of crosslinking points in the structure of the resulting copolymer increases, which significantly reduces the elongation of the intraocular lens, causing cracks or breakage when the lens is folded compactly, and also reduces the refractive index of the resulting copolymer, which requires a thicker optical part.

[0029] The degree of hydrophilicity of the resulting copolymer can be adjusted depending on the type of alkylene oxide group in the di(meth)acrylate (C). As a result, the effect of suppressing glistening and whitening of intraocular lenses can be further improved. Examples of the alkylene oxide group in the di(meth)acrylate (C) include an ethylene oxide group and a propylene oxide group. The alkylene oxide group preferably contains an ethylene oxide group. Specifically, the alkylene oxide group is preferably an ethylene oxide group alone or a combination of an ethylene oxide group and a propylene oxide group. In this case, the degree of hydrophilicity of the resulting copolymer can be further increased.

[0030] For example, a di(meth)acrylate having only an ethylene oxide group is represented by the following general formula (I). [In the formula, X is a methyl group or a hydrogen atom, and n is an integer of 12 or more and 30 or less.] In the above general formula (I), n is preferably an integer of 13 or more and 28 or less, more preferably an integer of 14 or more and 26 or less, and even more preferably an integer of 15 or more and 26 or less.

[0031] Furthermore, for example, a di(meth)acrylate having an ethylene oxide group and a propylene oxide group is represented by the following general formula (II). [wherein X is a methyl group or a hydrogen atom, n １ and n ２ are each independently an integer of 4 or more and 15 or less, and m is an integer of 6 or more and 20 or less.] In the above general formula (II), n １ and n ２ are each independently preferably an integer of 5 or more and 14 or less, more preferably an integer of 6 or more and 13 or less, and even more preferably an integer of 7 or more and 12 or less. m is also preferably an integer of 7 or more and 20 or less, more preferably an integer of 8 or more and 19 or less, and even more preferably an integer of 9 or more and 18 or less.

[0032] The proportion of the di(meth)acrylate represented by the general formula (I) in the di(meth)acrylate (C) is approximately 60 mol% or more, preferably approximately 70 mol% or more, more preferably approximately 80 mol% or more, even more preferably approximately 90 mol% or more, and may be approximately 100 mol%. In this case, the effect of suppressing the occurrence of glistening and whitening of the intraocular lens can be further enhanced. When the di(meth)acrylate (C) contains a di(meth)acrylate other than the di(meth)acrylate represented by the general formula (I), this other di(meth)acrylate is preferably a di(meth)acrylate represented by the general formula (II). That is, the di(meth)acrylate (C) preferably further contains a di(meth)acrylate represented by the following general formula (II). In this case, it becomes easier to adjust the degree of hydrophilicity of the resulting copolymer.

[0033] The content of di(meth)acrylate (C) in the intraocular lens material is preferably about 0.5 mol% to about 3.5 mol%, more preferably about 1 mol% to about 3.5 mol%, and even more preferably about 1.5 mol% to about 3.5 mol%. When the content is expressed in mass%, the content of di(meth)acrylate (C) in the intraocular lens material is preferably about 5% to about 20% by mass, more preferably about 7% to about 20% by mass, and even more preferably about 7% to about 18% by mass. This further improves the effect of suppressing the occurrence of glistening and whitening in the intraocular lens, and also further improves the effect of suppressing the occurrence of cracks and breakage when the lens is folded compactly by adjusting the elongation.

[0034] <Crosslinkable Monomer (D)> The crosslinkable monomer (D) is a type of auxiliary monomer that is blended into the monomer mixture for the purpose of adjusting the mechanical strength and elongation of the intraocular lens, etc. Specific examples of the crosslinkable monomer (D) include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,3-propanediol di(meth)acrylate, 2,3-propanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate. Among these, ethylene glycol dimethacrylate and 1,4-butanediol diacrylate are preferred as the crosslinkable monomer (D). These compounds may be used alone or in combination of two or more.

[0035] The content of crosslinkable monomer (D) in the intraocular lens material is preferably less than about 3 mol%, more preferably less than about 2.5 mol%, and even more preferably less than about 2 mol%. When the content is expressed in mass%, the content of crosslinkable monomer (D) in the intraocular lens material is preferably about 2 mass% or less, more preferably about 1.5 mass% or less, and even more preferably about 1 mass% or less. By keeping the content of crosslinkable monomer (D) within the above range, it is possible to supplementarily impart mechanical strength to the intraocular lens, adjust the elongation rate of the intraocular lens, and prevent it from becoming brittle.

[0036] <UV-Absorbing Reactive Monomer (E)> The UV-absorbing reactive monomer (E) (hereinafter also referred to simply as "reactive monomer (E)") is, for example, a monomer that has a structure capable of absorbing UV light and is blended into the monomer mixture for the purpose of imparting UV-absorbing ability to an intraocular lens. Specific examples of the reactive monomer (E) include 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole, 2-hydroxy-4-(methacryloyloxy)benzophenone, 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole, 2-(2-hydroxy-3-(methacryloxyaminomethyl)-5-tert-octylphenyl)-2H-benzotriazole, and 3-(3-(tert-butyl)-4-hydroxy-5-(5-methoxy-2H-benzo[d][1,2,3]triazol-2-yl)phenoxy)propyl methacrylate. Among these, 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole and 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole are preferred as the reactive monomer (E). These compounds may be used alone or in combination of two or more.

[0037] The content of the reactive monomer (E) in the intraocular lens material is preferably about 0.5 mol% or less, and more preferably about 0.2 mol% to 0.4 mol%. When the content is expressed in mass%, the content of the reactive monomer (E) in the intraocular lens material is preferably about 1 mass% or less, and more preferably about 0.3 mass% to 0.6 mass%.

[0038] <Reactive Monomer (F) Having Colorability> The reactive monomer (F) having colorability (hereinafter also simply referred to as "reactive monomer (F)") is a monomer that has a structure capable of absorbing blue light and exhibits a yellow color, and is blended into a monomer mixture for the purpose of coloring an intraocular lens, for example. Azo-based, pyrazolone-based, or cyanine-based yellow colorants can be used as this reactive monomer (F). Specific examples of the reactive monomer (F) include the yellow colorants described in JP-A-10-195324, JP-A-2000-290256, JP-A-2003-119226, JP-A-2008-520811, JP-A-2008-520352, and JP-A-2012-532244. All of the contents of these publications are incorporated herein by reference.

[0039] The content of the reactive monomer (F) in the intraocular lens material is preferably about 0.03 mol% or less, and more preferably about 0.008 mol% to 0.025 mol%. When the content is expressed in mass%, the content of the reactive monomer (F) in the intraocular lens material is preferably about 0.05 mass% or less, and more preferably about 0.01 mass% to 0.04 mass%. The mono(meth)acrylates (A), (B), and di(meth)acrylate (C) described above, along with the crosslinkable monomer (D) and reactive monomers (E) and (F), if necessary, and the polymerization initiator (G), are mixed and thoroughly stirred to obtain a homogeneous monomer mixture.

[0040] <Polymerization Initiator (G)> As the polymerization initiator (G), either a thermal polymerization initiator or a photopolymerization initiator can be used. Examples of the thermal polymerization initiator include peroxides such as di(4-tert-butylcyclohexyl)peroxydicarbonate, di(3,5,5-trimethylhexanoyl)peroxide, dilauroyl peroxide, benzoyl peroxide, tert-hexylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, and tert-butylperoxy-2-ethylhexanoate, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), dimethyl-1,1'-azobis(1-cyclohexanecarboxylate), and 1,1'-azobis(cyclohexane-1-carbonitrile).

[0041] Examples of photopolymerization initiators include benzoin methyl ether, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. The content of the polymerization initiator (G) in the intraocular lens material is appropriately selected depending on the polymerization temperature in the thermal polymerization, the wavelength and intensity of light irradiation in the photopolymerization, and other factors, but is preferably approximately 0.1 mol % to 1 mol % relative to the total amount (100 mol %) of monomers (A) to (F) and (H). When the content is expressed in mass %, the content of the polymerization initiator (G) in the intraocular lens material is preferably approximately 0.2 mol % to 0.8 mol %.

[0042] <<Intraocular Lens>> FIG. 1 is a plan view showing the configuration of an intraocular lens. The intraocular lens 1 includes an optical portion 2 that transmits light and a pair of haptics 3 that protrude outward from opposing positions of the optical portion 2 and support the optical portion 2 within the eye. Each haptic 3 is curved in an arc. In this intraocular lens 1, both the optical portion 2 and the pair of haptics 3 are composed of a copolymer, which is a polymer of intraocular lens material. The total length L of the intraocular lens 1 is preferably approximately 11 mm to 15 mm, and more preferably approximately 12 mm to 14 mm. The diameter D of the optical portion 2 is preferably approximately 5 mm to 7 mm, and more preferably approximately 5.5 mm to 6.5 mm. The center thickness of the optical portion 2 is preferably approximately 0.4 mm to 0.9 mm, and more preferably approximately 0.4 mm to 0.8 mm.

[0043] The width W1 of the haptics 3 on the optical section 2 side is designed to be larger than the width W2 of the haptics 3 on the side opposite the optical section 2. Specifically, the width W1 of the haptics 3 on the optical section 2 side is preferably approximately 0.4 mm or more and 0.7 mm or less, and more preferably approximately 0.5 mm or more and 0.65 mm or less. On the other hand, the width W2 of the haptics 3 on the side opposite the optical section 2 is preferably approximately 0.3 mm or more and 0.6 mm or less, and more preferably approximately 0.3 mm or more and 0.4 mm or less. The thickness of the haptics 3 is preferably approximately 0.25 mm or more and 0.45 mm or less, and more preferably approximately 0.3 mm or more and 0.4 mm or less. The optical section 2 and the pair of haptics 3 may be fabricated as separate bodies using a copolymer (a polymer of an intraocular lens material) and then bonded together, but are preferably integrally formed using the copolymer. By using the above-mentioned intraocular lens material, the optical section 2 and haptics 3 having the required characteristics can be obtained collectively.

[0044] The elongation of the copolymer (polymer of intraocular lens material) at 23°C is preferably about 150% or more, more preferably about 200% or more, and even more preferably about 250% or more. From the viewpoint of the shape recovery of the intraocular lens 1, the elongation of the copolymer at 23°C is preferably about 600% or less. This can suitably prevent cracks or breakage when the intraocular lens 1 is folded compactly, and can be inserted into the lens capsule through a small incision. Herein, "elongation" refers to the elongation of a rectangular test specimen formed from the intraocular lens material being tested. For example, "having an elongation of 200%" means that when a rectangular test specimen having a total length of 15 mm, a width of 1 mm, and a thickness of 0.35 mm is fabricated and pulled to breakage under a test environment of 23°C and 50% humidity at a grip distance of 6 mm and a test speed of 100 mm / min, the grip distance at breakage is 18 mm.

[0045] The glass transition temperature of the copolymer (polymer of intraocular lens material) is preferably about 3° C. or higher but lower than 17° C., more preferably about 4° C. or higher but lower than 17° C., and even more preferably about 5° C. or higher but lower than 17° C. If the copolymer has a glass transition temperature of 3° C. or higher, it can be easily processed into the intraocular lens 1. On the other hand, if the copolymer has a glass transition temperature of less than 17° C., the intraocular lens 1 can be folded with little force, and it is also possible to prevent a delay in the time it takes for the lens to return to its original shape inside the eye.

[0046] The intraocular lens 1 has a higher compressive load of the haptics 3 than conventional intraocular lens materials. When the pair of haptics 3 of the intraocular lens 1 are brought close together so that the maximum separation distance between them is 13 mm to 10 mm, the load measured at each haptic 3 is preferably about 0.35 mN or more, more preferably about 0.36 mN or more, and even more preferably about 0.37 mN or more. The upper limit of the compressive load of the haptics 3 is preferably 1.8 mN, which is equivalent to the compressive load of the haptics of a 3P-type intraocular lens whose haptic material is made of PMMA. If the compressive load of the haptics 3 is about 0.35 mN or more, the compressive load is higher than that of conventional 1P-type intraocular lenses, and therefore the stability of the intraocular lens 1 within the lens capsule can be improved. On the other hand, if the compressive load of the haptics 3 is about 1.8 mN or less, it is possible to suitably prevent the haptics 3 from damaging the lens capsule when the intraocular lens 1 is inserted.

[0047] When the copolymer (polymerized material for intraocular lens) is in a dry state and its refractive index is measured at 23°C with an Abbe refractometer using e-line (546.1 nm), it is preferably about 1.535 or more, more preferably about 1.540 or more, and even more preferably about 1.545 or more. By making the refractive index 1.535 or more, the central thickness of the optical part 2 can be made thinner, making it easier to fold the intraocular lens 1 into a small shape. There are no particular limitations on the upper limit of the refractive index, but considering that the Abbe number tends to decrease as the refractive index increases, it is preferably 1.570.

[0048] When the intraocular lens is in a dry state and the optical part 2 is folded in half at 23°C, the load (compression load) is preferably about 30 gf or more and 800 gf or less, more preferably about 30 gf or more and 750 gf or less, and even more preferably about 30 gf or more and 700 gf or less. When an injector is used to simplify the insertion of the intraocular lens 1 into the eye, if the compression load is 30 gf or more, the optical part 2 is less likely to twist when the intraocular lens 1 is ejected, and it is possible to fold it neatly. On the other hand, if the compression load is 800 gf or less, the user can eject the intraocular lens 1 with little force.

[0049] The water content of the copolymer (polymer of intraocular lens material) in physiological saline at 23° C. is preferably about 0.5% to 3%, more preferably about 0.5% to 2.9%, and even more preferably about 0.5% to 2.8%. By making the water content of the intraocular lens 1 about 0.5% or more, it is possible to more reliably prevent the occurrence of glistening and whitening of the intraocular lens 1. On the other hand, by making the water content of the intraocular lens 1 about 3% or less, it is possible to prevent a decrease in the refractive index of the intraocular lens 1 due to water absorption.

[0050] The intraocular lens 1 has high resistance to glistening and whitening. Here, the evaluation of resistance to glistening and whitening is performed by the following procedure. First, an intraocular lens 1 having an optical zone 2 with a diameter of 6.0 mm and a central thickness of 0.6 mm to 0.7 mm is immersed in physiological saline at 45°C for 24 hours or more. Next, the intraocular lens 1 is left immersed in physiological saline for 2 hours in an environment set to 23°C. Thereafter, the appearance (transparency) of this intraocular lens 1 is observed at a magnification of 20x or more using, for example, a stereomicroscope (Nikon Solutions Corporation, "SMZ-745T").

[0051] In this specification, "glistening" refers to a state in which several to several tens of water particles having a particle size of approximately 1 μm to 10 μm are generated in the intraocular lens 1, but there is no substantial decrease in the transparency of the intraocular lens 1. On the other hand, "whitening" refers to a state in which the surface of the intraocular lens 1 appears misty and white due to the aggregation of a large number of minute water particles having an average particle size of 100 nm.

[0052] The evaluation of glistening and whitening is based on the temperature changes within the eye that are thought to occur during ophthalmic surgery to actually insert the intraocular lens 1 into a human eye, or on the temperature changes in the living environment after the intraocular lens 1 is inserted into the eye. It is believed that these temperature changes within the body cause glistening and whitening in the intraocular lens 1. Generally, for intraocular lenses 1 with a low water content, the higher the temperature, the higher the water content. Therefore, evaluation of glistening and whitening over a wider range of temperature changes (23°C or higher and 45°C or lower) can be considered to be carried out under more severe conditions. With the intraocular lens 1, glistening and whitening are unlikely to occur even under such severe conditions.

[0053] The intraocular lens 1 as described above can be produced as follows. First, a monomer mixture is poured into a mold for producing an intraocular lens that corresponds to the shape of the intraocular lens 1 to be produced, and then polymerized. This mold is a laminated mold with a curved recess formed therein, and is made of a material such as a metal material, a glass or quartz material, or a resin material. However, it is preferable that the material be one that allows the polymer of the monomer mixture (intraocular lens material or intraocular lens 1) to be easily released from the mold and that has excellent solvent resistance and heat resistance. A resin mold is preferred because it is easy to mold and can be molded into the shape required for the desired lens design.

[0054] The resin material is preferably selected from those having a low molding shrinkage rate, good surface transferability from a metal molding die, and excellent dimensional accuracy, solvent resistance, and heat resistance. Polypropylene is particularly preferred as the resin material because it is inexpensive and easily available. However, the resin material is not limited to polypropylene, and other materials such as polyethylene, polyacetal, polyethylene terephthalate, cycloolefin polymer, polymethylpentene, and ethylene-vinyl alcohol copolymer may also be used. When injecting the monomer mixture, the mold may be used immediately after molding, or it may be used after storing for 24 to 72 hours to stabilize the shape (curvature) of the curved recess.

[0055] Furthermore, before using the mold, the pressure may be sufficiently reduced to remove substances that may affect the radical polymerization reaction, such as moisture and oxygen, from the mold surface, and the mold may be purged with an inert gas such as nitrogen gas or argon gas before the monomer mixture is poured into the mold. Alternatively, a simpler method may be used, such as using a device like a gas filter gun to spray an inert gas such as nitrogen gas or argon gas onto the mold surface, and then pouring the monomer mixture into the mold. Furthermore, when pouring the monomer mixture, the monomer mixture may be previously bubbled with an inert gas such as nitrogen gas or argon gas to remove dissolved oxygen from the monomer mixture before use, or the monomer mixture may be used without removing the dissolved oxygen.

[0056] Examples of polymerization methods include thermal polymerization, in which a thermal polymerization initiator is added to a monomer mixture and the mixture is heated, and photopolymerization, in which a photopolymerization initiator is added to a monomer mixture and the mixture is irradiated with ultraviolet or visible light. When using thermal polymerization, the mold is placed in a polymerization apparatus and heated in a stepwise manner within a temperature range of about room temperature to about 120°C for about 10 to 48 hours, or the mold is placed in a polymerization apparatus pre-set to a constant temperature (about 100°C to about 120°C) and heated for about 1 to 10 hours. The atmosphere during thermal polymerization is preferably an inert gas atmosphere such as nitrogen or argon gas. By performing thermal polymerization in such an atmosphere, the polymerization rate of the monomer can be improved and the amount of unpolymerized monomer can be reduced. In this case, the pressure inside the polymerization apparatus is preferably atmospheric pressure or pressurized (about 0.196 MPa or less).

[0057] When using the photopolymerization method, the wavelength of the irradiated light is appropriately selected depending on the characteristics of the photopolymerization initiator blended, and is not particularly limited. Specific examples of lamps used for irradiating light include lamps with strong peaks in the wavelength range of 200 nm to 280 nm and 350 nm, lamps that emphasize wavelengths in the range of 350 nm to 400 nm, lamps that emphasize wavelengths in the range of 400 nm to 425 nm with a wavelength of 420 nm as the center, and lamps that emphasize wavelengths in the range of 400 nm to 450 nm. The irradiation intensity of light varies depending on the light receiving area of ​​the measuring device, but is, for example, 1 mW / cm. ２ 100mW / cm or more ２ It is preferable that the temperature is about the same or less.

[0058] The light irradiation time (polymerization time) is not particularly limited, as it is appropriately set depending on the light irradiation intensity. For example, ２ 100mW / cm or more ２ In the case where the irradiation time is about 5 minutes or more and about 60 minutes or less, the photopolymerization is preferably performed in an inert gas atmosphere such as nitrogen or argon gas. By performing the photopolymerization in such an atmosphere, the polymerization rate of the monomer can be improved and the amount of unpolymerized monomer can be reduced.

[0059] After the monomer mixture liquid is cured by thermal polymerization or photopolymerization, it is preferable to perform a reheating treatment to further reduce unpolymerized monomer. In this reheating treatment, first, the upper mold of the mold after polymerization is completed is removed, and the mold is placed in a heat treatment device with the polymerized (cured) monomer mixture liquid contained in the lower mold. Next, after gradually reaching a predetermined temperature within a temperature range from room temperature to 115°C or higher and 125°C or lower, the mold is continuously heated at that temperature for approximately 12 hours to 48 hours, and then cooled to room temperature. This reheating treatment makes it possible to reduce the amount of unpolymerized monomer remaining in the polymerized monomer mixture liquid to near the detection limit (approximately less than 1 μg / mL) in quantitative analysis by gas chromatography or high-performance liquid chromatography.

[0060] During this reheating treatment, unpolymerized monomers can be efficiently removed from the polymer of the monomer mixture by continuously flowing a constant flow rate of air or nitrogen gas into and out of the heat treatment device. The greater the flow rate of the gas flowing into the heat treatment device, the more efficiently the unpolymerized monomers can be removed, but a flow rate of approximately 10 L / min to 100 L / min is preferred. After polymerization of the monomer mixture, the polymer of the monomer mixture is removed from the mold, or without removing the polymer of the monomer mixture from the mold (i.e., while the polymer of the monomer mixture is contained in the mold), by cutting and, in some cases, polishing the polymer of the monomer mixture at a low temperature to form a desired shape (e.g., the shape of the intraocular lens itself).

[0061] Alternatively, the monomer mixture may be polymerized in a suitable mold or container to produce a polymer of the monomer mixture in a desired shape, such as a rod, block, or plate. The polymer may then be machined into the desired shape by cutting at low temperature and, in some cases, polishing. Therefore, the polymer of the monomer mixture before processing can also be considered an intraocular lens material. Alternatively, the monomer mixture may be injected into a mold having the final shape of the intraocular lens, and after polymerization and reheating, the polymer of the monomer mixture may be removed and used as an intraocular lens without cutting or polishing. Furthermore, the surface of the optical portion 2 of the intraocular lens 1 may be subjected to a cleaning treatment using low-temperature plasma, atmospheric pressure plasma, ultraviolet light, or the like. Such treatments can improve the cleanliness and cell adhesiveness of the surface of the optical portion 2 of the intraocular lens 1.

[0062] Next, another configuration of the intraocular lens will be described. Fig. 7 is a plan view showing another configuration of the intraocular lens. The intraocular lens 1 shown in Fig. 7 will be described below, focusing on the differences from the intraocular lens 1 shown in Fig. 1, and a description of similar points will be omitted. The intraocular lens 1 shown in Fig. 7 is similar to the intraocular lens 1 shown in Fig. 1 except for the shape of each haptic 3.

[0063] Each haptic part 3 has a wide portion 31 with an increased width midway along its longitudinal direction. This makes it possible to increase the mechanical strength of each haptic part 3 while maintaining the ease of deformation of each haptic part 3. Furthermore, the tip portion 32 of each haptic part 3 (the end opposite the optical part 2) is rounded. This makes it difficult for each haptic part 3 to damage the lens capsule when inserting the intraocular lens 1 into the lens capsule, regardless of its orientation. Furthermore, the haptic part 3 may be provided in each of the following modes.

[0064] (1) An intraocular lens material comprising a mono(meth)acrylate (A) having an aryl group in its molecular structure, a mono(meth)acrylate (B) different from the mono(meth)acrylate (A) and having an aryl group in its molecular structure, and a di(meth)acrylate (C) having an alkylene oxide group in its molecular structure, wherein the content of the mono(meth)acrylate (A) in the intraocular lens material is 45 mol % or more and 70 mol % or less, the total content of the mono(meth)acrylate (A) and the mono(meth)acrylate (B) is 85 mol % or more, and the proportion of the di(meth)acrylate represented by the following general formula (I) in the di(meth)acrylate (C) is 60 mol % or more. [In the formula, X is a methyl group or a hydrogen atom, and n is an integer of 12 or more and 30 or less.]

[0065] (2) The intraocular lens material according to (1) above, wherein the content of the di(meth)acrylate (C) in the intraocular lens material is 0.5 mol % or more and 3.5 mol % or less.

[0066] (3) In the intraocular lens material described in (1) or (2) above, the glass transition temperature of the homopolymer of the mono(meth)acrylate (A) is higher than the glass transition temperature of the homopolymer of the mono(meth)acrylate (B).

[0067] (4) In the intraocular lens material described in any one of (1) to (3) above, the glass transition temperature of the homopolymer of the mono(meth)acrylate (A) is 40°C or higher.

[0068] (5) In the intraocular lens material described in any one of (1) to (4) above, the glass transition temperature of the homopolymer of the mono(meth)acrylate (B) is less than 40°C.

[0069] (6) In the intraocular lens material described in any one of (1) to (5) above, the alkylene oxide group of the di(meth)acrylate (C) contains an ethylene oxide group.

[0070] (7) The intraocular lens material according to (6) above, wherein the di(meth)acrylate (C) further contains a di(meth)acrylate represented by the following general formula (II): [wherein X is a methyl group or a hydrogen atom, n １ and n ２ are each independently an integer of 4 or greater and 15 or less, and m is an integer of 6 or greater and 20 or less.

[0071] (8) The intraocular lens material according to any one of (1) to (7) above, wherein the polymer of the intraocular lens material has an elongation of 150% or more at 23°C.

[0072] (9) The intraocular lens material according to any one of (1) to (8) above, wherein the glass transition temperature of the polymer of the intraocular lens material is 3°C or higher and lower than 17°C.

[0073] (10) An intraocular lens comprising an optical portion that transmits light and a pair of support portions that protrude outward from opposing positions of the optical portion and support the optical portion within the eye, wherein both the optical portion and the pair of support portions are made of a polymer of the intraocular lens material described in any one of (1) to (9) above.

[0074] (11) In the intraocular lens described in (10) above, the optical portion and the pair of support portions are integrally formed by the polymer.

[0075] (12) In the intraocular lens according to (10) or (11) above, when the pair of support parts are brought closer together so that the maximum separation distance between them is 10 mm from 13 mm, the load measured at each of the support parts is 0.35 mN or more. Of course, this is not a limitation.

[0076] As described above, various embodiments of the present invention have been described, but these are presented as examples and do not limit the scope of the invention in any way. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Such embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as set forth in the claims.

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. 1. Components Used The names and abbreviations of the compounds used in the following examples and comparative examples are shown below.

[0078] 1-1. Mono(meth)acrylates (A) having an aryl group in the molecular structure: PE-MA: 2-phenylethyl methacrylate [molecular weight: 190, homopolymer Tg: 42.3°C] PO-MA: 2-phenoxyethyl methacrylate [molecular weight: 206, homopolymer Tg: 48.8°C] BZ-MA: benzyl methacrylate [molecular weight: 176, homopolymer Tg: 65.3°C]

[0079] 1-2. Mono(meth)acrylates having an aryl group in the molecular structure (B) PPr-MA: 3-phenylpropyl methacrylate [molecular weight: 204, homopolymer Tg: 17.8°C] PB-MA: 4-phenylbutyl methacrylate [molecular weight: 218, homopolymer Tg: 4.0°C] PE-A: 2-phenylethyl acrylate [molecular weight: 176, homopolymer Tg: -4.0°C] PO-A: 2-phenoxyethyl acrylate [molecular weight: 192, homopolymer Tg: 10.0] POB-A: 3-phenoxybenzyl acrylate [molecular weight: 254, homopolymer Tg: 10.7°C]

[0080] 1-3. Di(meth)acrylates (C) having alkylene oxide groups P600DMA: polyethylene glycol dimethacrylate [molecular weight: 750, number of repeating ethylene oxide groups (average) is 13] P1000DMA: polyethylene glycol dimethacrylate [molecular weight: 1136, number of repeating ethylene oxide groups (average) is 23] 40PDC-1700B: polyethylene glycol-polypropylene glycol dimethacrylate 40PDC-1700B is represented by the following formula, where m is about 18 and n １ and n ２ is about 9 and the molecular weight is 2007.

[0081] 1-4. Crosslinking Monomer (D) EDMA: ethylene glycol dimethacrylate [molecular weight: 198] BDDA: 1,4-butanediol diacrylate [molecular weight: 198]

[0082] 1-5. Reactive monomers having ultraviolet absorbing properties (E) Norbloc: 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole [molecular weight: 323] o-MTP: 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole [molecular weight: 279]

[0083] 1-6. Colorable reactive monomer (F) MOAB: trans-4-(phenylazo)phenyl methacrylate [molecular weight: 266]

[0084] 1-7. Polymerization initiator (G) AIBN: 2,2'-azobisisobutyronitrile [molecular weight: 164] t-BPO: tert-butyl peroxyoctoate [molecular weight: 216] Perkadox: bis(4-tert-butylcyclohexyl) peroxydicarbonate [molecular weight: 399] BP: benzoyl peroxide [molecular weight: 242]

[0085] 1-8. (Meth)acrylates (H) having an ethylene oxide group other than di(meth)acrylates (C) P200MMA: methoxytetraethylene glycol methacrylate [molecular weight: 287, number of repeating ethylene oxide groups (average) is 4] P400DA: polyethylene glycol diacrylate [molecular weight: 522, number of repeating ethylene oxide groups (average) is 9] 4-ArmPEG35: polyethoxylated tetramethylolmethane tetraacrylate [molecular weight: 1892]

[0086] 4-ArmPEG35 is a macromonomer represented by the following formula (D1), in which the total number of repetitions (average value) of l, m, n, and o is 35.

[0087] 2. Preparation of Homopolymer (Homopolymer 1) First, 10 g of PE-MA and 0.04 g of AIBN (0.46 mol %, 0.4 mass % relative to PE-MA) were placed in a 20 mL glass bottle and stirred at room temperature for approximately 18 hours. Next, this monomer mixture was poured into a mold (made of polypropylene) to prepare a coin-shaped polymer with a final shape of 16 mm in diameter and 0.6 mm in thickness, and the upper and lower molds were assembled. Next, this mold was placed in a polymerization apparatus and polymerization was carried out according to the following schedule.

[0088]

[0089] After the polymerization, only the upper mold was removed, leaving the polymer in the lower mold. The mold was then placed in a heat treatment device and reheated according to the following schedule to obtain a plate-shaped polymer.

[0090] (Homopolymers 2 to 8) Similarly, 10 g of PO-MA, BZ-MA, PPr-MA, PB-MA, PE-A, PO-A or POB-A and 0.04 g of AIBN were weighed out, and a disk-shaped polymer was prepared in the same manner as for Homopolymer 1.

[0091] 3. Measurement of Glass Transition Temperature (Tg) First, a test specimen was extracted from the disk-shaped polymer obtained above using a 5 mm diameter biopsy trephine. Next, this test specimen was sealed by adhering it to the bottom of an aluminum container used for differential scanning calorimetry. At this time, the mass of the test specimen was approximately 10 mg or more and 13 mg or less. Next, using an empty aluminum container as a reference material, the glass transition temperature was measured using a DSC3500 Sirius manufactured by NETZSCH according to the following schedule:

[0092]

[0093] The midpoint glass transition temperature of the obtained DSC chart was determined as the glass transition temperature of the homopolymer. To eliminate a certain amount of thermal strain, the second heating data (data from Step 8 in Table 3) was used for analysis. As a result, the glass transition temperatures of each homopolymer were as follows:

[0094]

[0095] 4. Preparation of Intraocular Lenses (Example 1) The following amounts of PE-MA, PE-A, P1000DMA, Norbloc, MOAB, and AIBN were weighed into a 20 mL glass bottle and stirred at room temperature for approximately 18 hours to prepare a monomer mixture.

[0096] PE-MA: 5.520 g (58.87 mol%, 55.20 mass%) PE-A: 3.387 g (39.00 mol%, 33.87 mass%) P1000DMA: 1.054 g (1.88 mol%, 10.54 mass%) Norbloc: 0.0375 g (0.235 mol%, 0.375 mass%) MOAB: 0.00197 g (0.015 mol%, 0.0197 mass%) AIBN: 0.04 g (0.494 mol%, 0.40 mass%) relative to the total amount of PE-MA, PE-A, P1000DMA, Norbloc, and MOAB

[0097] Next, this monomer mixture was poured into a mold (made of polypropylene) for producing an intraocular lens with a refractive power of +20.0 D, a mold (made of polypropylene) for producing a coin-shaped polymer with a final shape of 16.5 mm in diameter and 0.6 mm in thickness, and a mold (made of polypropylene) for producing a coin-shaped polymer with a final shape of 16 mm in diameter and 0.35 mm in thickness, and an upper mold was attached. Thereafter, the molds were placed in a polymerization apparatus and polymerized and reheated in the same manner as for Homopolymer 1, to obtain an intraocular lens.

[0098] (Examples 2 and 3) Intraocular lenses were produced in the same manner as in Example 1, except that the monomer mixture shown in Table 5 was prepared. (Comparative Examples 1 and 2) Intraocular lenses were produced in the same manner as in Example 1, except that the monomer mixture shown in Table 5 was prepared.

[0099] 5. Measurement and Evaluation For the intraocular lenses obtained in each Example and Comparative Example, the glass transition temperature of the copolymer, the water content, the compressive load of the haptics, the refractive index, the tensile breaking elongation, the compressive load of the optic zone, and glistening / whitening were evaluated.

[0100] 5-1. Measurement of the glass transition temperature (Tg) of the copolymer To measure the glass transition temperature of the copolymer, a test specimen was extracted from a coin-shaped polymer of intraocular lens material having a diameter of 16.5 mm and a thickness of 0.6 mm using a biopsy trephine with a diameter of 5 mm. The glass transition temperature of this test specimen was measured in the same manner as in "3. Measurement of the glass transition temperature (Tg)" above.

[0101] 5-2. Measurement of Water Content In measuring water content, the unprocessed cured intraocular lens material prepared using a mold for intraocular lens production was used as a test specimen. The test specimen was then placed in a low-temperature vacuum dryer pre-set at 60°C ± 5°C and dried under vacuum conditions (1 mmHg or more and 2 mmHg or less) for 2 hours (2 hours ± 1 hour). Next, the specimen was placed in a desiccator and cooled to room temperature, after which its mass was measured to one decimal place. This procedure was repeated until the mass of the test specimen became constant within ± 0.1 mg, and this was taken as the dry mass (mass: Wd).

[0102] The test specimens with known masses were placed one by one in embedding cassettes with assigned identification numbers, and then placed in a glass container containing 500 mL of physiological saline. This glass container was immersed in a water bath previously set at 23°C ± 1°C for 72 hours ± 1 hour. After the specified time of immersion, the test specimens were removed, the surface moisture was wiped off with a clean cloth, and the mass of the test specimen was measured to one decimal place (mass Ww). After all measurements were completed, the moisture content was calculated according to the following formula: Moisture content (%) = {(Ww - Wd) / Ww} × 100

[0103] 5-3. Measurement of compressive load of haptics In measuring the compressive load of haptics, an intraocular lens obtained by processing a polymerized intraocular lens material produced in a mold for intraocular lens production was used. The specifications of the intraocular lens were as follows: Total length L of intraocular lens: 13.0 mm Diameter D of optical zone: 6.0 mm, central thickness: 0.65 mm Width W1 of haptics on the optical zone side: 0.65 mm, width W2 opposite to the optical zone: 0.35 mm, thickness: 0.35 mm

[0104] The compression load of the haptics was measured in accordance with ISO 11979-3:2012. FIG. 2 is a diagram showing the intraocular lens set on the stage of a haptics compression load measuring device. FIG. 3 is a diagram showing the intraocular lens in a state where the separation distance between the haptics of the intraocular lens is compressed to 10 mm. Specifically, the intraocular lens 1 was set on the stage 10 of the haptics compression load measuring device (see FIG. 2), and compressed from 13.0 mm to 10.0 mm (see FIG. 3), and the stress accompanying the deformation of the haptics 3 was measured. The load (mN) at this time was taken as the compression load of the haptics 3. The results were evaluated using the load when compressed to 10.0 mm, and the measurement was performed in distilled water at 37°C.

[0105] 5-4. Measurement of refractive index For the measurement of refractive index, a rectangular test piece 10 mm wide and 15 mm long was cut out from a coin-shaped polymer of intraocular lens material 16.5 mm in diameter and 0.6 mm thick. The refractive index of this test piece at 23°C for e-line (546.1 nm) was measured using a multi-wavelength Abbe refractometer (manufactured by Atago Co., Ltd., "DR-M2").

[0106] 5-5. Measurement of Tensile Elongation at Break To measure the tensile elongation at break, a rectangular test piece 15 mm long and 1 mm wide was cut out from a coin-shaped polymer of intraocular lens material with a diameter of 16.5 mm and a thickness of 0.35 mm. The test piece was then clamped between the grippers of a universal testing machine (Instron Japan, "3342"). The distance between the grippers was 6 mm. The test piece was pulled at a rate of 100 mm / min in an environment of 23°C and 50% humidity, and the tensile elongation at break was calculated from the elongation at break according to the following formula:

[0107] (Calculation formula) EB = (L - L0) / L0 x 100 EB: Elongation (tensile breaking elongation) (%) L: Distance between grips at break (mm) L0: Distance between grips at the original position of the test piece (mm)

[0108] 5-6. Measurement of Compressive Load of Optical Zone To measure the compressive load of the optical zone, a polymerized intraocular lens material prepared using a mold for intraocular lens production was processed into an intraocular lens. The bases of the haptics were cut off from the resulting intraocular lens, and only the portion corresponding to the optical zone was used as a test specimen. Figure 4 shows the state in which the optical zone of the intraocular lens was set on the stage for measuring the compressive load of the optical zone. Figure 5 shows the state in which the optical zone of the intraocular lens was compressed to 3 mm and folded in half. This test specimen was then fixed vertically on the stage of a universal material testing machine (Instron Japan, "3342") (see Figure 4). In this state, the test specimen was folded from 6 mm to 3 mm at a speed of 100 mm / min under an environment of 23°C and 50% humidity (see Figure 5), and the maximum load (gf) at this time was taken as the compressive load of the optical zone.

[0109] 5-7. Evaluation of glistening / whitening In the evaluation of glistening / whitening, an intraocular lens obtained by processing a polymerized intraocular lens material produced in a mold for intraocular lens production was used. The specifications of the intraocular lens were as follows: Total length L of intraocular lens: 13.0 mm Diameter D of optical zone: 6.0 mm, central thickness: 0.65 mm Width W1 of haptic zone on the optical zone side: 0.65 mm, width W2 on the opposite side to the optical zone: 0.35 mm, thickness: 0.35 mm

[0110] The test piece was then immersed in saline at 45°C for 48 hours, and then left to stand for 2 hours in an environment set at 23°C. Thereafter, the appearance (transparency) of the test piece in the saline was observed at 50x magnification using a stereomicroscope (Nikon Solutions Corporation, "SMZ-745T") and evaluated according to the following evaluation criteria. <Evaluation criteria> G (Good): The test piece had excellent transparency, and no water particles were observed inside. B (Bad): The test piece was cloudy (whitening), or transparent, but water particles were observed inside (glistening).

[0111] The results are shown in Table 5 below and in FIG.

[0112] In Table 5, the units for the content of each monomer and polymerization initiator are mol% in the upper row and % by mass in the lower row in parentheses. The content of polymerization initiator (G) is expressed as a percentage of the total amount (100 mol%) of the moles of monomers (A) to (C), (E), and (F) or the total amount (100 mass%) of the masses. Figure 6 is a graph showing the relationship between the distance between haptics (compression distance) and the compression load for Examples 1 to 3 and Comparative Examples 1 and 2. As shown in Table 5 and Figure 6, the intraocular lenses obtained in Examples 1 to 3 had copolymer glass transition temperatures of 9.0°C, 14.2°C, and 16.4°C, tensile elongations at break of 325%, 370%, and 394%, and compression loads at the haptics of 0.689 mN, 0.733 mN, and 0.811 mN. FIG. 6 also shows the value of the compressive load (1.8 mN) of the haptics of a 3P type intraocular lens whose haptics are made of polymethyl methacrylate (PMMA).

[0113] In contrast, the intraocular lenses of Comparative Examples 1 and 2 obtained using a monomer mixture containing no mono(meth)acrylate (A) had copolymer glass transition temperatures of -3.4°C and -9.0°C, tensile break elongations of 148% and 130%, and haptic compressive loads of 0.192 mN and 0.171 mN. Thus, the intraocular lenses of Examples 1 to 3 obtained using a monomer mixture containing 45 mol% to 70 mol% of mono(meth)acrylate (A) have sufficient flexibility and elongation, and high haptic compressive loads, and are therefore considered to have improved intraocular stability compared to conventional 1P-type intraocular lenses. Furthermore, the haptic compressive loads are lower than those of conventional 3P-type intraocular lenses, making them easier to handle.

[0114] Examples 4 to 10 Intraocular lenses were produced in the same manner as in Example 1 above, except that a monomer mixture solution was prepared having the composition shown in Table 6. Table 6 below shows the composition of the monomer mixture solution, as well as the results of measurements of the glass transition temperature of the copolymer, the water content, the compressive load of the haptics, the refractive index, the tensile elongation at break, the compressive load of the optic portion, and an evaluation of glistening / whitening.

[0115]

[0116] In Table 6, the units for the contents of each monomer and polymerization initiator are mol% in the upper row and % by mass in parentheses in the lower row. The content of polymerization initiator (G) is expressed as a percentage of the total number of moles (100 mol%) or total mass (100 mass%) of monomers (A) to (D). As shown in Table 6, the intraocular lenses obtained in Examples 4 to 10 have sufficient flexibility and elongation, and have high compressive loads on the haptics, and are therefore considered to have improved stability within the eye compared to conventional intraocular lenses.

[0117] (Example 11, Comparative Example 3) Intraocular lenses were produced in the same manner as in Example 1, except that a monomer mixture solution was prepared having the composition shown in Table 7. Table 7 below shows the composition of the monomer mixture solution, as well as the results of measurements of the glass transition temperature of the copolymer, the water content, the compressive load of the haptics, the refractive index, the tensile elongation at break, the compressive load of the optic portion, and an evaluation of glistening / whitening.

[0118]

[0119] In Table 7, the units for the contents of each monomer and polymerization initiator are mol% in the upper row and % by mass in parentheses in the lower row. The content of polymerization initiator (G) is expressed as a percentage of the total number of moles (100 mol%) or the total mass (100 mass%) of monomers (A) to (C) and (H). As shown in Table 7, the intraocular lens obtained in Example 11 has sufficient flexibility and elongation, and has a high compressive load of the haptics, and is therefore considered to have improved stability in the eye compared to conventional intraocular lenses.

[0120] On the other hand, the intraocular lens of Comparative Example 3, which was obtained using an intraocular lens material containing a tetrafunctional (meth)acrylate (H) having an ethylene oxide group, had an extremely low tensile elongation at break due to the increased number of crosslinking points, and the compressive load of the haptics was lower than that of the intraocular lens of Example 11. Furthermore, when a compressive load test of the optic zone was conducted, the optic zone broke into two when folded to 3 mm. Therefore, the intraocular lens of Comparative Example 3 was not suitable as an intraocular lens that is folded compactly and inserted into the eye.

[0121] (Comparative Examples 4 to 8) A monomer mixture solution having the composition shown in Table 8 was prepared, heated to 80°C in a nitrogen gas circulating oven, maintained at 80°C for 1 hour, then heated to 110°C and maintained at 110°C for 2 hours, to produce an intraocular lens. The mold used was the same as in Example 1. (Comparative Example 9) A monomer mixture solution having the composition shown in Table 8 was prepared, heated to 80°C in a nitrogen gas circulating oven, maintained at 80°C for 2 hours, then heated to 100°C and maintained at 100°C for 3 hours, to produce an intraocular lens. The mold used was the same as in Example 1.

[0122] (Comparative Examples 10 and 11) A monomer mixture solution having the composition shown in Table 8 was prepared, heated to 80°C in a nitrogen gas circulating oven, maintained at 80°C for 1 hour, and then heated to 110°C and maintained at 110°C for 2 hours to produce an intraocular lens. The mold used was the same as in Example 1. (Comparative Example 12) An intraocular lens material was produced in the same manner as in Example 1, except that a monomer mixture solution having the composition shown in Table 8 was prepared.

[0123]

[0124] In Table 8, the units for the contents of each monomer and polymerization initiator are mol% in the upper row and % by mass in parentheses in the lower row. The content of polymerization initiator (G) is expressed as a percentage of the total amount (100 mol%) of the moles of monomers (A) to (E) and (H) or the total amount (100 mass%) of the masses. As shown in Table 8, the intraocular lens of Comparative Example 4 was produced using an intraocular lens material in which the content of mono(meth)acrylate (A) exceeded the range of the present invention and did not contain mono(meth)acrylate (B). As a result, the glass transition temperature of the copolymer was high, and the intraocular lens of Comparative Example 4 was so hard that it was difficult to fold in half, making it unsuitable as an intraocular lens.

[0125] The intraocular lens of Comparative Example 5 was produced using an intraocular lens material that contained a large amount of mono(meth)acrylate (B), a homopolymer with a high glass transition temperature, and also contained a crosslinkable monomer (D), but did not contain di(meth)acrylate (C). As a result, the glass transition temperature of the copolymer was high, and the intraocular lens of Comparative Example 5 was not only too hard to fold in half, but also suffered from glistening, making it unsuitable as an intraocular lens. The intraocular lenses of Comparative Examples 6 and 8 were produced using an intraocular lens material that did not contain mono(meth)acrylate (A). As a result, not only were the glass transition temperatures of the copolymers low, but the compressive load of the haptics was also low.

[0126] The intraocular lens of Comparative Example 7 was produced using an intraocular lens material that did not contain mono(meth)acrylate (A) or di(meth)acrylate (C). Therefore, the intraocular lens of Comparative Example 7 had a low compressive load at the haptics and also exhibited glistening, making it unsuitable as an intraocular lens material. The intraocular lens of Comparative Example 9 was produced using an intraocular lens material that contained a large amount of monofunctional methacrylate (H) containing an ethylene oxide group, instead of di(meth)acrylate (C). Therefore, the intraocular lens of Comparative Example 9 had a low glass transition temperature of the copolymer and a low compressive load at the haptics.

[0127] The intraocular lens of Comparative Example 10 was produced using an intraocular lens material in which the content of mono(meth)acrylate (A) was below the range of the present invention and which contained a monofunctional methacrylate (H) containing an ethylene oxide group instead of the di(meth)acrylate (C). Therefore, the intraocular lens of Comparative Example 10 not only had low glass transition temperature of the copolymer, low tensile elongation at break, and low compressive load of the haptics, but also exhibited glistening, making it unsuitable as an intraocular lens. The intraocular lens of Comparative Example 11 was produced using an intraocular lens material in which the content of mono(meth)acrylate (A) was below the range of the present invention. Therefore, the intraocular lens of Comparative Example 11 had low glass transition temperature of the copolymer, low tensile elongation at break, and low compressive load of the haptics.

[0128] The intraocular lens of Comparative Example 12 was produced using an intraocular lens material containing diacrylate (H) in which the number of repeating ethylene oxide groups was 9, which is lower than the range of the present invention. For this reason, the intraocular lens of Comparative Example 12 not only had a low compressive load at the haptics, but also suffered from glistening, making it unsuitable as an intraocular lens.

[0129] Examples 12 and 13, Comparative Examples 13 and 14 Intraocular lens materials were prepared in the same manner as in Example 1, except that a monomer mixture solution having the composition shown in Table 9 was prepared.

[0130]

[0131] In Table 9, the units for the contents of each monomer and polymerization initiator are mol% in the upper row and % by mass in parentheses in the lower row. The content of polymerization initiator (G) is expressed as a percentage of the total amount of moles (100 mol%) or the total amount of mass (100 mass%) of monomers (A) to (C). As shown in Examples 12 and 13, when a di(meth)acrylate (C) containing a predetermined amount or more of polyethylene glycol dimethacrylate (i.e., a di(meth)acrylate (C) containing less than a predetermined amount of polyethylene glycol-polypropylene glycol dimethacrylate) was used, whitening or glistening did not occur, and other physical properties were also favorable for an intraocular lens material.

[0132] On the other hand, as shown in Comparative Examples 13 and 14, when a di(meth)acrylate (C) containing less than the predetermined amount of polyethylene glycol dimethacrylate (i.e., a di(meth)acrylate (C) containing a predetermined amount or more of polyethylene glycol-polypropylene glycol dimethacrylate) was used, whitening or glistening occurred, making the material unsuitable as an intraocular lens material. Note that in Comparative Examples 13 and 14, since whitening or glistening occurred, measurements of other physical properties were omitted.

[0133] 1: intraocular lens, 2: optical part, 3: support part, 31: wide part, 32: tip part, 10: stage, L: total length, D: diameter, W1: width of support part on the optical part side, W2: width of support part opposite to the optical part

Claims

1. An intraocular lens material comprising: a mono(meth)acrylate (A) having an aryl group in its molecular structure; a mono(meth)acrylate (B) different from the mono(meth)acrylate (A) and having an aryl group in its molecular structure; and a di(meth)acrylate (C) having an alkylene oxide group in its molecular structure, wherein the content of the mono(meth)acrylate (A) in the intraocular lens material is 45 mol % or more and 70 mol % or less, the total content of the mono(meth)acrylate (A) and the mono(meth)acrylate (B) is 85 mol % or more, and the proportion of the di(meth)acrylate represented by the following general formula (I) in the di(meth)acrylate (C) is 60 mol % or more. [In the formula, X is a methyl group or a hydrogen atom, and n is an integer of 12 to 30.] 2. The intraocular lens material according to claim 1, wherein the content of the di(meth)acrylate (C) in the intraocular lens material is 0.5 mol % or more and 3.5 mol % or less.

3. An intraocular lens material according to claim 1 or 2, wherein the glass transition temperature of the homopolymer of the mono(meth)acrylate (A) is higher than the glass transition temperature of the homopolymer of the mono(meth)acrylate (B).

4. The intraocular lens material according to any one of claims 1 to 3, wherein the homopolymer of the mono(meth)acrylate (A) has a glass transition temperature of 40°C or higher.

5. The intraocular lens material according to any one of claims 1 to 4, wherein the glass transition temperature of the homopolymer of the mono(meth)acrylate (B) is lower than 40°C.

6. An intraocular lens material according to any one of claims 1 to 5, wherein the alkylene oxide group of the di(meth)acrylate (C) contains an ethylene oxide group.

7. The intraocular lens material according to claim 6, wherein the di(meth)acrylate (C) further contains a di(meth)acrylate represented by the following general formula (II): [In the formula, X is a methyl group or a hydrogen atom, n １ and n ２ are each independently an integer of 4 or more and 15 or less, and m is an integer of 6 or more and 20 or less.

8. An intraocular lens material according to any one of claims 1 to 7, wherein the elongation of the polymer of said intraocular lens material at 23°C is 150% or more.

9. An intraocular lens material according to any one of claims 1 to 8, wherein the glass transition temperature of the polymer of said intraocular lens material is 3°C or higher and lower than 17°C.

10. An intraocular lens comprising: an optical portion that transmits light; and a pair of support portions that protrude outward from opposing positions of the optical portion and support the optical portion within the eye, wherein both the optical portion and the pair of support portions are made of a polymer of the intraocular lens material described in any one of claims 1 to 9.

11. The intraocular lens according to claim 10, wherein the optical portion and the pair of support portions are integrally formed from the polymer.

12. An intraocular lens as claimed in claim 10 or 11, wherein when the pair of support parts are brought closer together so that the maximum separation distance between them is 10 mm from 13 mm, the load measured at each of the support parts is 0.35 mN or more.

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