JPH04158859A - Artificial cornea - Google Patents

Abstract

PURPOSE:To enable the maintaining of transparency almost permanently in vivo without fear of rejection by arranging an optical part comprising a resin material and a support part which holes a specified fluororesin mechanically while being sutured on a cornea. CONSTITUTION:Raw material of an optical part 1 is the most preferably an acrylic resin with a safety thereof already established. On the other hand, a support part 2 herein used is made of a soft porous fluororesin. It was conformed that the porous fluororesin allows microfibrils and cells of a blood vessel to penetrate into pores thereof, which achieves a continuous healing. Then, to bond the optical part made of the acrylic resin on the support part made of the porous fluororesin, a non-solvent type adhesive is used. For example, it is of an ultraviolet hardening type, epoxy type, cyanoacrylate type or the like. The adhesive is selected considering safety to a cornea. In the method using no such a adhesive, the support part made of the porous fluororesin is retained within a mold formed into a shape of a lens to polymerize the optical part and the two parts can be put together simultaneously with the polymerization of the optical part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an artificial cornea that is used as a substitute for corneal ablation surgery for corneal diseases.

[Prior Art] Blindness due to corneal clouding still occurs at a fairly high frequency, although there are large regional differences. In the final stage of various corneal diseases, irreversible corneal clouding often occurs and blindness occurs. However, recently, intraocular lens surgeries have increased, and corneal opacity as a complication has also increased. In the final stages of glaucoma, some patients also become blind due to corneal clouding.

Corneal transplants are now being performed to save these patients. However, in reality, it is not easy to obtain transplanted corneas, and it is not carried out satisfactorily. Furthermore, if the condition of the patient's cornea is poor, rejection is likely to occur, and the cornea will not be suitable for transplantation and will be left alone.

If an artificial cornea becomes possible, surgery will be easier to perform at any time, and there will be no need to worry about graft opacity due to rejection or blood vessel invasion. If the cornea could become transparent, it would be a great blessing to many patients who are able to obtain light. Furthermore, if conventional corneal transplantation becomes unnecessary, there will be great social benefits.

Many artificial corneas have been prototyped to date, but most have failed. Currently, intraocular lenses have been successfully developed, and many transparent and harmless materials have been developed.

However, in the case of an intraocular lens, the artificial lens is simply inserted into the capsule of the Kolaken left after the nucleus of the crystalline lens is removed, and continuous adhesion between living tissue and inanimate matter is not required.

In contrast, artificial corneas require continuous adhesion between living tissue and inanimate matter. This point was the biggest bottleneck in the development of artificial corneas. Among the conventional methods, the method with the highest success rate was to use the patient's own teeth as a support for the artificial cornea.

In other words, the patient's own tooth is cut out into a disk shape, the center of the disk is punched out, an artificial cornea is attached, and the tooth portion is sutured to the cornea. Because the teeth and cornea are both own tissues, they fuse continuously without any rejection reaction. Teeth are tissues that are difficult to metabolize, and can be semi-permanently attached to an artificial cornea. However, this method has not become popular due to the disadvantage to patients of having to extract a normal tooth and the technical problem of polishing the tooth.

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned problems. The purpose of the present invention is to provide an artificial cornea that can be continuously fused with the cornea.

[Means for Solving the Problems] That is, the present invention comprises an optical part made of a transparent plastic material that transmits visible light, and a soft porous fluororesin, which mechanically holds the optical part and sutures it to the cornea. This is an artificial cornea characterized by comprising a support part.

The optical part in the present invention is located in the center of the artificial cornea,
It fulfills its function by being transparent and having an appropriate optical refractive index. Any plastic material that meets these conditions can be used, but since the inner surface of the artificial cornea comes into direct contact with the aqueous humor in the eye, it must be made of a material that is harmless to the human body and has established safety standards. It is desired that Therefore, the most preferable material for the optical part is acrylic resin, whose safety has already been established as a material for intraocular lenses.

On the other hand, the support portion is made of a soft porous fluororesin.

Soft porous fluororesins are currently used as artificial blood vessels. It has been confirmed that blood vessel fibers and cells enter the pores of the porous fluororesin, resulting in continuous coalescence. It has also been confirmed that it fuses not only with blood vessels but also with ligaments and bones in a continuous manner. Using this material, continuous fusion of the cornea and the inanimate object is achieved.

Next, a method of bonding the porous fluororesin supporting part and the acrylic resin optical part will be described.

The simplest bonding method is bonding with various adhesives.

Among adhesives, solvent-diluted adhesives are not preferred because they pose a risk of deterioration of the optical part due to the solvent or corneal damage due to residual solvent. Examples of non-solvent adhesives include:
Examples include ultraviolet curing types, epoxy types, cyanoacrylate types, etc., but these also need to be selected in consideration of safety to the cornea.

In addition, in order to bond without using an adhesive, a supporting part made of porous fluororesin prepared in advance is held in a lens-shaped mold for polymerizing the optical part, and at the same time the optical part is polymerized. It can also be glued.

[Example] Hereinafter, using a configuration example of the artificial cornea of the present invention shown in the drawings,
The present invention will be described in detail.

Example-1 95 parts by weight of methyl methacrylate, 5 parts by weight of ethylene glycol dimethacrylate, and 0.1 part by weight of azobis(2,4-dimethylvvaleronitrile) were mixed. Put this comonomer in a test tube, seal it, and heat it at 30"C for 10
time, 5 hours at 35°C, 3 hours at 40°C, 45°C
Polymerization was carried out by heating for 3 hours at 90°C and 3 hours at 90°C. The obtained bar material was cut and further polished to create an optical section 1 as shown in FIG.

Voretex (trademark of Japan Goretex), a soft porous fluororesin, EPTFE Patch II (heart and
Vascular system batch) was punched out into concentric circles of 10 mm and 5 mm to create donut-shaped support portions 2.

The optical part 1 and the support part 2 created by the above are
Treatment was performed with oxygen plasma at 1 torr and 60 W for 1 minute. Adhesive UV-210 (
Amicon Co., Ltd. trademark) and attach optical part 1 and support part 2 to the first
They were fitted as shown in the figure, and ultraviolet rays were irradiated for 20 seconds using a 3 kW metal halide lamp to create an artificial cornea.

Example 2 The support portion 2 produced in the same manner as in Example 1 was subjected to plasma treatment in the same manner as described above.

This support part 2 is assembled into a mold consisting of a glass plate 4 and a spacer 5 shown in FIG. It was filled with comonomer consisting of 0.1 part by weight of dicarbonate. Heat this at 40°C for 5 hours.
Heating polymerization was carried out by raising the temperature from 90°C to 90°C for 10 hours, and the mold was released to prepare an artificial cornea.

[Effects of the Invention] The functions and safety of both the acrylic resin used as the optical part and the soft porous fluororesin used as the support part have been established. However, by combining these two, new functionality is created. In other words, an artificial cornea is possible by combining the transparency of acrylic resin and its action as a lens upon formation, and the ability of soft porous fluororesin to form continuous bruises with living tissues and adhesiveness to inanimate objects. . Soft porous fluororesin is extremely resistant to traction, but can also be easily threaded with a needle and sutured to the cornea. Even if tissue can invade soft porous fluororesin, tissue or blood vessels will not invade acrylic resin, so there is no fear of rejection. Therefore, transparency can be maintained semi-permanently in vivo.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the structure of the artificial cornea of the present invention. FIG. 2 is a sectional view showing an example of creating the artificial cornea of the present invention by cast polymerization. 1... Optical section 2... Support section 3... Adhesive section 4... Glass plate 5.・・・・・・・・・Spacer and above Applicant Seiko Epson Corporation Baba Shoji Co., Ltd. Agent Patent attorney Kizobe Suzuki (and 1 other person) Notebook 2

Claims (1)

[Claims] An artificial cornea comprising an optical part made of a transparent plastic material that transmits visible light, and a support part made of a soft porous fluororesin that mechanically holds the optical part and is sutured to the cornea.