JPH0736836B2 - Intraocular lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention restores visual acuity by inserting the lens into the anterior chamber or posterior chamber of the aphakic eye after a lensectomy operation by Shirakohi etc. The present invention relates to an intraocular lens (artificial lens) that enables the above.

[Conventional technology]

As a method of visual acuity recovery (refractive correction) of a patient who has aphakic eye after lensectomy due to cataract or the like, use of eyeglasses, contact lens wearing, and intraocular lens implantation are performed.

However, although optician can obtain visual acuity after surgery, it suffers from narrowing of the visual field (enlargement of the retinal image) and the Jack in the box phenomenon, etc. I have to endure for a while. Further, particularly in the case of a monocular aphakic eye, the binocular vision function cannot be obtained due to unequal vision. Wearing contact lenses is effective for such anisoscopic vision, and nowadays, high water content soft contact lenses, etc. have been developed to enable continuous wear, and this problem is being solved, but patients are aged. Since most of them are people who are difficult to handle, there are few people who actually wear them even after prescription after surgery.

[Problems to be solved by the invention]

As such, correction with eyeglasses and contact lenses is not a preferred method. On the other hand, artificial lens transplantation is a method that has already been performed for 30 years,
The artificial lens, so-called intraocular lens, does not enlarge the retinal image, has no visual field constriction or annular scotoma, and can obtain binocular vision function (one eye aphakic eye is particularly superior to spectacles). ), It doesn't take a long time to get used to it, and once transplanted, it has no advantages because it is not handled. In recent years, due to the development of microscopes and ultrasonic scalpels, transplant surgery procedures have been improved, and the shape and material of intraocular lenses have been further improved.The above intraocular lenses are the most future method for correcting vision in aphakic eyes. It is important.

As described above, the intraocular lens is very excellent in vision correction, but the intraocular lens is a foreign body in the eye, and therefore an eye complication is a problem. There are also examples of arrival. Therefore, it is required that the material for the intraocular lens is not biotoxic, has excellent biocompatibility, and is not modified or deteriorated by the living body.

By the way, natural light also includes ultraviolet rays, visible rays and wavelengths in the infrared region, and transmission of a large amount of ultraviolet rays into the eye may cause damage to the retina. Since the crystalline lens of the eye also plays the role of protecting the retina by preferentially absorbing the above-mentioned ultraviolet rays, the transmission of ultraviolet rays becomes a serious problem in the aphakic eye as described above. For this reason,
As a material for the intraocular lens, it is desired that it absorbs ultraviolet rays in the range of 200 to 380 nm and is transparent to visible light in the range of 380 to 780 nm. Further, if the intraocular lens itself is heavy, it imposes a burden on the eye. Therefore, it is desired that the material has a low specific gravity and a high refractive index so that the lens thickness can be reduced.

Currently, the most used intraocular lens is polymethylmethacrylate (PMMA). This PMMA has excellent optical properties, is resistant to acids, alkalis, and organic solvents, and is also resistant to aging.

However, the above PMMA has a glass transition temperature (Tg) of 100.
Autoclave sterilization using steam cannot be performed due to low thermal stability below ℃. That is, autoclave sterilization is usually performed under the conditions of 121 ° C., 1.2 atmospheric pressure and about 1 hour, and under these conditions, PMMA is softened and deformed, making it unusable. Therefore, PMMA
The intraocular lens made of is sterilized by a sterilization method using ethylene oxide gas, etc., but gas remains in the lens, which may cause irritation to mucous membranes when placed in the eye. . Therefore, in the above-mentioned gas sterilization method, degassing is an essential step, which requires about 2 weeks, which results in high cost and is more expensive than the steam autoclave sterilization method. .
Also, since PMMA transmits a considerable amount of ultraviolet rays, the ultraviolet rays can cause damage to the retina as described above. Therefore, as disclosed in JP-A-60-232149, it has been attempted to solve the above problems by adding an ultraviolet absorber. However, the addition of the ultraviolet absorber in this way also deteriorates the transmittance of visible light, and the ultraviolet absorber may gradually seep out from the lens, which may adversely affect the living body. Not really. In addition, since the PMMA has a refractive index as small as about 1.4 as compared with glass, the lens may become thick and the lens may adhere to the pupil to cause complications.

Thus, while PMMA has many advantages, it also has many drawbacks.
Various materials that can be sterilized by autoclave, can absorb ultraviolet rays, and have a high refractive index have been studied. For example, glass has a high refractive index and is capable of absorbing ultraviolet rays, but it is difficult to process and the specific gravity is large (2.5), so the lens itself becomes heavy and the burden on the eye becomes large, so it is not suitable as an intraocular lens. There is a problem in use. Natural crystals or synthetic crystals of sapphire, ruby, corundum, silicon, diamond, etc. also have a UV-leveling ability, but like glass, they are difficult to process and have a large specific gravity. Inappropriate. Therefore, in recent years, interest in synthetic resins replacing PMMA has increased, and polysulfones, polyarylates, polyetherimides, and the like have been investigated. The polysulfone has a high refractive index and also has an ultraviolet absorbing property, and has a softening point of 175 ° C. and can be sterilized by autoclave, but it is difficult to process, so it should be put to practical use. I can't. Further, polyarylate also has a high refractive index and ultraviolet absorptivity and can be sterilized by autoclave, but like polysulfone, it has a problem in processability and is difficult to put into practical use. Polyetherimide has a high refractive index, ultraviolet absorptivity, autoclave sterilization properties, and good processability, but it is colored yellow or yellow-brown, and its visible light transmission is too low. It cannot be used as an inner lens.

In this way, PMMA has the above-mentioned drawbacks, but no alternative material has been found. Therefore, expensive gas sterilization is applied to sterilize PMMA, and optical and biological The fact is that the material is used as an intraocular lens material by adding an ultraviolet absorber that may adversely affect the eyes.

Therefore, it can be easily processed into a thin lens shape by machining or molding, the specific gravity is 1.7 or less, preferably 1.5 or less, the refractive index is 1.5 or more, preferably 1.6 or more, Furthermore, there is a strong demand for the development of an intraocular lens material that is chemically stable and biocompatible, absorbs UV rays that are dangerous to the retina, and has heat resistance that enables autoclave steam sterilization. Has been.

The present invention has been made in view of such circumstances, and is excellent in biocompatibility and ultraviolet absorptivity, has a small specific gravity, a large refractive index, is chemically stable, and has heat resistance that enables autoclave steam sterilization. The purpose is to provide an intraocular lens provided.

[Means for solving problems]

In order to achieve the above object, the intraocular lens of the present invention,
A lens part and a fixing part for fixing the lens part in the eye are provided, and the lens part is composed of a colorless transparent polyimide containing a repeating unit represented by the following general formula (I) as a main component. There is something.

That is, the present inventors, in order to obtain an intraocular lens superior to the PMMA described above, as a result of repeated studies on a series of resins, aromatic polyimide completely absorbs ultraviolet rays,
Moreover, it has a large refractive index (1.6 or more) and has sufficient heat resistance for autoclave steam sterilization.
It has been found that it has superior characteristics compared to. However, since aromatic polyimide is colored yellow or brown, it absorbs not only ultraviolet rays but also visible rays. Therefore, as a result of repeated research on the development of an aromatic polyimide that does not absorb visible light, the present inventors have found that the aromatic polyimide represented by the general formula (I) completely absorbs ultraviolet rays and An intraocular lens that transmits most of visible light and is substantially transparent can be obtained. Furthermore, this product has various characteristics required for an intraocular lens like a conventional aromatic polyimide and is biocompatible. It was found that they were also excellent, and reached the present invention.

That is, the intraocular lens of the present invention has a lens portion that is biocompatible, chemically inert, does not undergo modification or deterioration from the living body side, has a refractive index of 1.6 or more, and is 200 to 380n.
A colorless and transparent polyimide [general formula (I) that completely absorbs ultraviolet rays in the m range, is substantially transparent to visible light in the 380 nm to 780 nm range, and has heat resistance that can withstand autoclave sterilization. The main component is the repeating unit represented by the above].

The intraocular lens of the present invention includes a lens section and a fixing section for fixing the lens section in the eye. The lens portion is composed of a colorless and transparent polyimide whose main component is the repeating unit represented by the general formula (I). Such colorless and transparent polyimide has the following general formula (II), It is obtained by the reaction of the biphenyltetracarboxylic dianhydride represented by the formula (I) with an aromatic diamino compound represented by the general formula (III).

H ₂ N-R-NH ₂ (III) The following are mentioned as said biphenyl tetracarboxylic dianhydride.

3,3 ', 4,4'-biphenyltetracarboxylic dianhydride 2,3,3 ', 4'-Biphenyltetracarboxylic acid dianhydride Examples of the aromatic diamino compound include the following.

3,3'-diaminodiphenyl ether 3,3'-diaminodiphenyl sulfone 3,3'-diaminodiphenyl thioether 3,3'-diaminodiphenylmethane 3,3'-diaminobenzophenone Bis [4- (3-aminophenoxy) phenyl] sulfone 2,2-bis [4- (3-aminophenoxy) phenyl]
propane 2,2-bis [4- (3-aminophenoxy) phenyl]
Hexafluoropropane m-phenylenediamine 2,4-tolylenediamine 4,6-Dimethyl-m-phenylenediamine 2,4-diaminomesitylene 4-chloro-m-phenylenediamine 3,5-diaminobenzoic acid 5-nitro-m-phenylenediamine 1,4-bis (3-aminophenoxy) benzene 1,3-bis (3-aminophenoxy) benzene The aromatic diamine may be used alone,
You may use it combining suitably.

By combining the above-mentioned biphenyl tetracarboxylic dianhydride with the above aromatic diamine having an amino group at the meta position, a colorless color containing a repeating unit represented by the general formula (I) as a main component for the first time. A transparent polyimide is obtained. Here, the term “main component” is intended to include a case where the whole is made up of only the main component. In this case, the greater the content of the repeating unit represented by the general formula (I), which is the main component of the colorless and transparent polyimide, the higher the colorless transparency of the obtained polyimide. However, if the repeating unit represented by the general formula (I) is contained in an amount of 80 mol% or more, at least the ultraviolet absorptivity and visible light transmittance required in the present invention can be secured. Using other aromatic tetracarboxylic dianhydrides other than 3,3'4,4'-diphenylsulfone tetracarboxylic acid dianhydride and other diamino compounds other than aromatic diamine having an amino group at the above meta position be able to. However, the preferable range of the content of the repeating unit represented by the general formula (I) is 80 mol% or more, and the most preferable range is 95 mol% or more.

As the other aromatic tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,3', 4,4'-
Benzophenone tetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 2,2-
Bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride can be mentioned, and these can be used alone or in combination.

Other diamino compounds include 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone and 4,4 '.
-Diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylpropane, p-
Phenylenediamine, benzidine, 3,3'-dimethylbenzidine, 4,4'-diaminodiphenylthioether,
3,3'-dimethoxy-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) propane, 2,2-
Examples thereof include bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, which can be used alone or in combination.

The colorless and transparent polyimide used as the material for the intraocular lens of this invention is a polyamic acid prepared by polymerizing the above-mentioned aromatic tetracarboxylic dianhydride and aromatic diamino compound in an organic polar solvent at a temperature of 80 ° C. or lower. Was synthesized, and a shaped body having a desired shape was formed using this polyamic acid solution, and the shaped body was heated in air or an inert gas under the conditions of temperature: 50 to 350 ° C., pressure: normal pressure or reduced pressure. The organic polar solvent is removed by evaporation and the polyamic acid is dehydrated and ring-closed to form a polyimide. The polyamic acid can also be obtained by a chemical imidization method such as using a benzene solution of pyridine and acetic anhydride to remove the solvent and imidize it to form a polyimide.

In the above-mentioned method, it is also possible to isolate the polyamic acid by reprecipitation and then dehydrate and ring-close with heat or a chemical imidizing agent to obtain a polyimide. further,
It is also possible to heat the solution after the polyamic acid synthesis as it is to 100 ° C. or more to imidize it, and obtain a polyimide as a precipitate from the solution. In this case, although filtering and washing are required, substantially the same colorless and transparent polyimide can be obtained.

As the above organic polar solvent, amide-based organic polar solvents such as N, N-dimethylformamide and N, N-dimethylacetamide are suitable. Particularly, those having a boiling point of 170 ° C. or less such as N, N-dimethylacetamide are preferable. These organic polar solvents may be used alone or as a mixture of two or more kinds without any problem. However, it is preferable to avoid using N-methyl-2-pyrrolidone as the organic polar solvent. N-methyl-2-pyrrolidone is heated by heating the shaped body of the polyamic acid solution, partially decomposed by heating during dehydration ring closure and polyimidization, and the decomposed product becomes black brown. This is because the polyimide produced tends to be colored yellowish brown. As the organic polar solvent, each of the solvents such as N, N-dimethylacetamide exemplified above has a low boiling point, and therefore volatilizes before being decomposed by the above heating, and N-methyl-2-
Does not cause coloration for polyimides such as pyrrolidone.

However, N-methyl-2-pyrrolidone is used as a polymerization solvent, and after the polyamic acid is synthesized, the polyamic acid solution is poured into a poor solvent for the polyamic acid, for example, water to reprecipitate the polyamic acid, and the In the case of forming an imide in the presence, or in the case of re-dissolving in another preferable solvent and then imidizing, the above-mentioned adverse effects of N-methyl-2-pyrrolidone can be eliminated.

When using the suitable organic polar solvent exemplified above, a poor solvent or a good solvent which does not impair the transparency, such as ethanol, toluene, benzene, xylene, dioxane, tetrahydrofuran, nitrobenzene, is used as the solvent.
One kind or two or more kinds may be appropriately mixed and used as long as the solubility is not impaired. However, if these solvents are used in a large amount, the solubility of the produced polyamic acid will be adversely affected. Therefore, it is reasonable to limit the amount used to less than 50% by weight of the total solvent, and the most preferable amount is 30% by weight.

As described above, the intrinsic viscosity (logarithmic viscosity) of the polyamic acid solution when producing a colorless transparent polyimide is 0.3 to 5.0.
It is preferably in the range of. 0.4-2.0 is more suitable
Is. The intrinsic viscosity is a value measured at a concentration of 0.5 g / 100 ml in N, N-dimethylacetamide. If the intrinsic viscosity is too low, the mechanical strength of the obtained intraocular lens becomes low, which is not preferable. On the other hand, if the intrinsic viscosity is too high, the work of shaping the polyamic acid solution into an appropriate shape or the work of isolating the polyamic acid becomes difficult, which is not preferable. Also, the concentration of the polyamic acid solution is preferably set to 5 to 30% by weight, preferably 15 to 25% by weight from the viewpoint of workability and the like.

The intrinsic viscosity is calculated by the following formula, and the viscosity in the formula is measured by a capillary viscometer.

Examples of methods for producing an intraocular lens using the colorless and transparent polyimide obtained as described above include the following methods.

The first method is to cast the polyamic acid solution on a mirror-finished glass plate, stainless plate, or the like so as to have a constant thickness, and gradually heat at a temperature of 100 to 350 ° C. to perform dehydration ring closure, A polyimide film is obtained by imidizing a polyamic acid. The removal of the organic polar solvent in the film formation from the polyamic acid solution and the heating for the imidization of the polyamic acid may be carried out continuously, or these steps may be carried out under reduced pressure or in an inert gas atmosphere. . Also, another method of forming a polyimide film is
100 by casting the above polyamic acid solution on a glass plate or the like.
By heating and drying at ~ 150 ° C for 30-120 minutes to form a film, this film is immersed in a benzene solution of pyridine and acetic anhydride for solvent removal and imidization reaction, and the above film is made into a polyimide film. Thus, a polyimide film can be obtained by this method as well. The required number of polyimide films thus obtained are stacked so as to form a plate-shaped body having a constant thickness, and the temperature is 200 to 400 ° C and the pressure is 0.5 to 10 t / c.
By performing thermocompression molding at m ² for 0.1 to 10 hours, a transparent polyimide molding can be obtained. An intraocular lens is obtained by polishing this into an intraocular lens shape using a polishing device.

The second method is to throw the polyamic acid solution into a poor solvent such as water or methanol to reprecipitate and recover the polyamic acid,
By dehydration ring closure by heating at a temperature of 100 ~ 350 ℃ to imidize, followed by crushing to obtain anhydrous transparent polyimide powder, using the powdered polyimide, the same temperature as above 200 ~ 400 ℃ By performing thermocompression molding at a pressure of 0.5 to 10 t / cm ² for 0.1 to 10 hours, a transparent polyimide molding can be obtained, which can be ground into an intraocular lens as described above.

In the second method, as another method of obtaining a powdery colorless transparent polyamide, the polyamic acid solution is heated to 100 to 200 ° C. with stirring to convert the polyamic acid into a polyimide, and as a precipitate. There is a method of precipitating out of the system, in which case it can be subjected to thermocompression molding only by cleaning and drying.

In this way, when an intraocular lens is produced using a colorless and transparent polyimide film or polyimide powder, the obtained intraocular lens has an intrinsic viscosity (concentration of 0.5 g / dl in 97% sulfuric acid of 97% sulfuric acid). Measured at 30 ° C)
It is preferably set within the range of 0.3 to 4.0. Most preferred is 0.4 to 2.0.

The third method is not a method of using thermocompression molding as in the first and second methods, but a method of directly obtaining a polyimide molded body from a polyamic acid. With conventional drying methods, foaming cannot be suppressed by such a method.
It is difficult to obtain a homogeneous polyimide molding of 0 μm or more. However, by leaving the polyamic acid solution under reduced pressure for a long time and heating it from the inside by using far infrared rays or microwaves, it is possible to obtain a polyimide molded body of 500 μm or more without foaming. That is,
By using such far infrared rays and microwaves, it is possible to directly obtain a homogeneous polyimide molding from the polyamic acid.

The intraocular lens can be manufactured from the polyimide molded body obtained by the above-described three kinds of methods, for example, by machining. That is, the lens is made by polishing the surface in accordance with the power, and then the hole for attaching the fixed part is NC processed (numerical control process), and the fixed part is welded to this hole by spot heating. be able to. An example of the intraocular lens thus obtained (intraocular lens for implantation in the posterior chamber of the human eye) is shown in FIGS. 1 and 2. In the figure, 1 is a lens portion, 2 is a hole for position adjustment formed along the circumference at the peripheral portion of the lens portion 1, 3 is the lens portion 1
Is a fixing part for fixing the inside of the eye.

The shape of the fixing portion 3 extends over a wide variety and can be changed as necessary. As the material of the fixing portion 3, polypropylene, polyvinylidene fluoride or the like is often used. However, with the intraocular lens of the present invention,
Materials made of these materials may be used, or materials made of other materials may be used. Further, colorless and transparent polyimide made of the same material as the lens portion may be used.

As described above, the lens part and the fixed part may be provided separately, and the lens part and the fixed part may be integrally formed instead of being joined together. In this case, since there is no joint between the two, it is possible to avoid the situation in which the fixed portion separates from the lens portion.

The intraocular lens thus obtained is extremely transparent, which is completely different from the one produced using the conventional aromatic polyimide.

The colorless and transparent polyimide used in this invention is
Visible light (500n
m) has a transmittance of 80% or more and a yellowness index (yellowness index) of 30 or less. When the lens portion of the intraocular lens of the present invention has a thickness of 1 mm, the total transmittance of visible light (total light transmittance) is 60% or more.

The lens portion of the intraocular lens of the present invention completely absorbs ultraviolet light, transmits most of the visible light, and is substantially transparent because the ultraviolet-visible light spectrum is measured and the transmittance is The point at which is zero (so-called cut-off point) is exactly the boundary point (380n) between the ultraviolet and visible light regions.
m), which is considered to be due to the fact that this cutoff occurs almost vertically. In aromatic polyimides other than the colorless and transparent polyimide used in the present invention, there are some cutoffs near 380 nm, but these gradually occur from the high wavelength side with a decrease in transmittance, and therefore the total light transmittance is It is significantly worse, and therefore cannot be applied to intraocular lens applications.

〔The invention's effect〕

As described above, the intraocular lens of the present invention is made by using a colorless transparent polyimide whose lens portion is obtained by combining biphenyl tetracarboxylic dianhydride and an aromatic diamine having an amino group at the meta position. Because
It can completely absorb ultraviolet rays in the 200-380 nm range,
Moreover, most of the visible light in the 380 to 780 nm region is transmitted, and it has substantial transparency. Therefore, when it is embedded in the eye, it can absorb harmful ultraviolet rays to protect the retina and provide sufficient visual acuity. Moreover, the colorless and transparent polyimide usually has a specific gravity of 1.3 to
In addition to being as small as 1.4, it has a refractive index of 1.6 to 1.7, which is larger than that of conventional PMMA, so that it can be made 30 to 50% thinner (thus lighter) than PMMA's if it has the same power. it can. Therefore, when implanted in the eye, the burden on the eye is light, and the possibility of contacting the cornea to cause complications is low and the safety is extremely high. Moreover, since the lens portion of the intraocular lens of the present invention is made of a colorless transparent polyimide which does not change in heat resistance from the conventional aromatic polyimide, it can be easily sterilized using the autoclave steam sterilization method. Therefore, cost reduction can be achieved.

The intraocular lens of the present invention can be used as an anterior chamber supporting lens and a posterior chamber supporting lens, and in some cases, an iris supporting lens, and includes all of them.

Next, examples will be described together with comparative examples.

Example 1 Using N, N-dimethylacetamide as a solvent,
To 1 mol of 3'-diaminodiphenyl sulfone, 3,
1 mol of 3 ', 4,4'-biphenyltetracarboxylic dianhydride was reacted to obtain a polyamic acid solution. The concentration of the polyamic acid polymer in this polyamic acid was set to be 20% by weight. This solution is cast on a glass plate to form a film, which is heated in a hot air dryer at 120 ° C for 60 minutes and 180 ° C for 60 minutes.
A polyimide film having a thickness of 50 μm was produced by heating at 250 ° C. for 3 hours and then at 300 ° C. for 30 minutes to imidize. When the infrared absorption spectrum of the polyimide film thus obtained was measured, absorption of amic acid was not observed, and a specific absorption of an imide group was observed at 1780 cm ^-1 .

The above polyimide film was punched with a punch having a diameter of 38 mmφ, 20 sheets were stacked and thermocompressed under the conditions of a temperature of 300 ° C., a pressure of 1 ton / cm ² , and a time of 30 minutes to produce a polyimide disk-shaped molded body having a thickness of 1 mm. This molded body was a homogeneous polyimide molded body in which the films were completely fused and integrated.

The ultraviolet-visible spectrum of the polyimide molded body thus obtained was measured to determine the wavelength at the cutoff point. Further, the total light transmittance, specific gravity and refractive index were obtained and the results are shown in Table 1 below. In addition, the results of the Preshacker-Kucker test at 121 ° C, 1.2 atm, and 24 hours were performed to examine the changes in appearance, and the results are also shown in the table.

Example 2 Bis [4- (3-aminophenoxy) phenyl] sulfone was used in place of 3,3′-diaminodiphenyl sulfone. A polyimide film was produced in the same manner as in Example 1 except for the above. In the infrared absorption spectrum of this film, there was no absorption of amic acid, and the specific absorption of the imide group was observed at 1780 cm ^-1 .

Using the polyimide film thus obtained, a polyimide molded product having a thickness of 1 mm was produced by the same procedure as in Example 1. In this molded product, the films were completely fused and integrated, and a uniform polyimide molded product was obtained. The wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index of this product were measured in the same manner as in Example 1 and are shown in Table 1. In addition, a pre-cleaker test was conducted in the same manner as in Example 1, and the results are also shown.

Example 3 Instead of 3,3′-diaminodiphenyl sulfone, 3,3′-
Diaminodiphenyl ether was used. A polyimide film was produced in the same manner as in Example 1 except for the above. In the infrared absorption spectrum of this film, there was no absorption of amic acid, and absorption of an imide group was observed at 1780 cm ^-1 .

Using the polyimide film thus obtained, a polyimide molded product having a thickness of 1 mm was produced by the same procedure as in Example 1. In this molded product, the films were completely fused and integrated, and a uniform polyimide molded product was obtained. The wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index of this product were measured in the same manner as in Example 1 and are shown in Table 1. In addition, a pre-cleaker test was conducted in the same manner as in Example 1, and the results are also shown in the same table.

Example 4 1,3-bis (3-aminophenoxy) benzene was used in place of 3,3′-diaminodiphenyl sulfone, and N, N-dimethylformamide was used in place of N, N-dimethylacetamide. . A polyimide film was produced in the same manner as in Example 1 except for the above. In the infrared absorption spectrum of this film, there was no absorption of amic acid, and absorption of an imide group was observed at 1780 cm ^-1 .

Using the polyimide film thus obtained, a polyimide molded product having a thickness of 1 mm was produced by the same procedure as in Example 1. In this molded product, the films were completely fused and integrated, and a uniform polyimide molded product was obtained. The wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index of this product were measured in the same manner as in Example 1 and are shown in Table 1. In addition, a pre-cleaker test was conducted in the same manner as in Example 1, and the results are also shown in the same table.

[Example 5] 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride was used in place of 3,3', 4,4'-biphenyltetracarboxylic dianhydride. A polyimide film was produced in the same manner as in Example 1 except for the above. In the infrared absorption spectrum of this film, there was no absorption of amic acid, and absorption of an imide group was observed at 1780 cm ^-1 .

Using the polyimide film thus obtained, a polyimide molded product having a thickness of 1 mm was produced by the same procedure as in Example 1. In this molded product, the films were completely fused and integrated, and a uniform polyimide molded product was obtained. The wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index of this product were measured in the same manner as in Example 1 and are shown in Table 1. In addition, a pre-cleaker test was conducted in the same manner as in Example 1, and the results are also shown in the same table.

[Comparative Example 1] 4,4'-instead of 3,3'-diaminodiphenyl sulfone
N-methyl-2-pyrrolidone was used in place of N, N-dimethylacetamide using diaminodiphenyl ether. A polyimide film was produced in the same manner as in Example 1 except for the above. In the infrared absorption spectrum of this film, there was no absorption of amic acid, and absorption of an imide group was observed at 1780 cm ^-1 .

Using the polyimide film thus obtained, a polyimide molded product having a thickness of 1 mm was produced by the same procedure as in Example 1. It was impossible to determine whether or not this molded product had a large coloring and was completely fused and integrated. The wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index of this product were measured in the same manner as in Example 1 and are shown in Table 1.

[Example 6] The polyamic acid solution obtained in Example 1 was poured into water to reprecipitate the polyamic acid, and the mixture was sufficiently stirred to remove the solvent, then recovered, washed with methanol, and then dried under reduced pressure. The polyamic acid powder thus obtained was heated in a hot air dryer to 250
It was imidized by heating to ℃. Then, it was pulverized into a fine powder.

Using the polyimide powder obtained as described above, thermocompression molding was performed under the conditions of a temperature of 300 ° C., a pressure of 1 ton / cm ² , and a time of 30 minutes to prepare a polyimide molded body having a thickness of 1 mm. In this molded product, the powders were completely fused and integrated with each other, and a homogeneous and transparent polyimide molded product was obtained.

With respect to the polyimide molded body thus obtained, the wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index were measured in the same manner as in Example 1 and shown in Table 1. In addition, a pre-cleaker test was conducted in the same manner as in Example 1, and the results are also shown in the same table.

Comparative Example 2 Using the polyamic acid solution obtained in Comparative Example 1, Example 6 was used.
A polyimide powder was prepared in the same manner as in.

Using the polyimide powder thus obtained, a polyimide molded body having a thickness of 1 mm was produced by the same procedure as in Example 6. This molded product was highly colored and the powders were not completely fused and integrated with each other.

With respect to the polyimide molded body thus obtained, the wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index were measured in the same manner as in Example 1 and shown in Table 1.

[Example 7] The polyamic acid solution obtained in Example 2 was put into a dish, put in a vacuum dryer and dried under reduced pressure for 24 hours at a temperature of 25 ° C, and then far-infrared rays were emitted while keeping the state under reduced pressure. Using 10
Heat treatment was performed at 0 ° C. for 48 hours, at 150 ° C. for 48 hours, and finally at 250 ° C. for 24 hours to prepare a polyimide molded body having a thickness of 0.8 mm.
This molded body was a homogeneous and transparent polyimide molded body.

With respect to the polyimide molded body thus obtained, the wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index were measured in the same manner as in Example 1 and shown in Table 1. In addition, a pre-cleaker test was conducted in the same manner as in Example 1, and the results are also shown in the same table.

Comparative Example 3 Using the polyamic acid solution obtained in Comparative Example 1, a polyimide molded body having a thickness of 0.8 mm was produced in the same manner as in Example 7. This molded product was homogeneous, but was a highly colored polyimide molded product.

With respect to the polyimide molded body thus obtained, the wavelength at the cutoff point, the total light transmittance, the specific gravity and the refractive index were measured in the same manner as in Example 1 and shown in Table 1.

[Example 8] An intraocular lens for rabbit eyes was produced using the polyimide molded body obtained in Example 7. The intraocular lens thus obtained was implanted in the anterior chamber of the rabbit eye to examine the effects for half a year. As a result, no toxic or harmful effects were observed. When the lens was taken out again and the optical characteristics were measured, it was exactly the same as before the embedding.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an intraocular lens for implantation in the posterior chamber of a human eye, and FIG. 2 is a side view of FIG. 1 ... Lens part, 2 ... Position adjusting hole, 3 ... Fixed part

Claims (2)

[Claims] 1. A colorless and transparent polyimide comprising a lens part and a fixing part for fixing the lens part in the eye, wherein the lens part is composed mainly of a repeating unit represented by the following general formula (I). An intraocular lens characterized in that it is composed of: 2. A lens part and a solid part are integrated, and both are composed of a colorless and transparent polyimide containing a repeating unit represented by the general formula (I) as a main component. The intraocular lens according to item 1.