JP3214894B2 - Artificial cornea and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial cornea used to replace a cornea having lost or lost visual function due to a corneal disease and to restore visual function.

[0002]

2. Description of the Related Art In general, an artificial cornea is fixed to an optical member made of a light-transmitting material having no harm to a living body and a surface of a natural (human body) cornea (hereinafter, abbreviated as a cornea) or an anterior layer of the cornea. And a support member that supports the optical member by being inserted between the back layer and the optical member, and is formed integrally with the same material, or a combination of the optical member and the support member made of different materials. was there.

The most common material used for such an artificial cornea is a synthetic resin material such as PMMA or silicon, and there has been an artificial cornea in which an optical member and a supporting member are integrally formed by using these materials. .

[0004] However, PM used for artificial cornea
Synthetic resin materials such as MA and silicone have no harm to living organisms, but on the other hand, they also do not have compatibility with living organisms, and therefore have poor affinity with the surrounding corneal tissue, and are not compatible with artificial corneas and corneas. There may be a small gap between them, through which bacteria can enter the anterior chamber and cause pancreatitis,
In addition, in severe cases, there is a problem that the artificial cornea is excreted from the cornea due to inflammation.

[0005] In addition to forming the optical member from the synthetic resin material described above, in order to improve compatibility with the living body, a so-called osteo, which is obtained by collecting a patient's own bone and processing it to form a support member, is used. -Odonto-keratop
rosthesis (Strampelli B. Os
teo-odonto-keratoprotheses
is, Ann. offal. , 89: 1039,19.
63).

However, after such an artificial cornea is implanted in the cornea, the support member and the cornea are well-adapted for a while, and the cornea is kept in a good condition. After that, the support member itself is gradually absorbed into the living body and decomposed. There was a problem of doing it.

Further, there has been an artificial cornea using alumina ceramics as a material of the artificial cornea and an optical member made of single-crystal alumina and a supporting member made of polycrystalline alumina. However, such an artificial cornea has many supporting members. Since it is made of crystalline alumina, the thickness is larger than that of the cornea having a thickness of 0.5 to 0.7 mm, so that the optical member must be fixed to the eyeball sclera or the eyelid by suture, and the surgical invasion becomes very large. In addition, it has not been put to practical use at present because of many complications in clinical trials.

Therefore, in order to solve the above-mentioned problems of the respective artificial corneas, an artificial cornea (Klin.oczna 84: 379-) proposed by Aradna Kurkova et al.
380 [1982]), an artificial cornea is used in which the optical member is formed of a synthetic resin material such as PMMA or silicon, and the support member is formed of a biocompatible metal material such as pure titanium, a titanium alloy or tantalum. Was.
Such artificial cornea optical member A having a cylindrical shape as shown in FIG. 8, and integrally with the left and right ring C and the ring C with a central hole C ₁ for fitting the optical member A forming flap D, from or composed prosthesis 20 support member B consisting of D, fitted a cylindrical optical element a in the central hole E ₁ of shield support member E such as shown in FIG. 9 artificial There was something like the cornea 30. These artificial corneas 2
In Nos. 0 and 30, the support members B and E are made of the above-mentioned metal material, so that they have good adaptability to the corneal tissue, and further, the thickness of the support members is extremely small, and there is an effect that there is almost no surgical invasion.

[0009]

However, in the above-mentioned artificial cornea, in which the supporting member is made of a biocompatible metal material, the supporting member has a flap shape, a shield shape, or the like. The difference in shape is large,
Some time after transplantation into the cornea, a part of the support member broke through the cornea and was exposed to the outside, and there was a problem that bacteria invaded the anterior chamber from that part and caused pancreatitis.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a method of using a cornea as a substitute for corneal transplantation or an optical material made of a light-transmitting material having no harm to the living body to replace the lost cornea. An artificial cornea formed by fitting a member into a central hole formed in a support member having a thickness of 0.03 to 0.3 mm made of a biocompatible metal material such as pure titanium, a titanium alloy or tantalum, The shape of the support member is a truncated dome shape having a curvature R of 6 to 9 mm as a whole, and a plurality of through holes are formed in the main body of the support material with an opening ratio of 20 to 70%. A central hole and a plurality of through holes are formed by photoetching on a thin plate made of an artificial cornea and a metal material, and a thick disk-shaped support member is processed, and the support member is pressed into a truncated dome shape. After molding, the support Method for producing the artificial cornea comprising the step of fitting the optical member to the center hole of the member is to provide.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an exploded perspective view of an artificial cornea 1 according to the present invention, and 2 is a main body 2c inserted between a front layer F and a rear layer N of a cornea K and fitted into a central hole 2a as shown in FIG. A supporting member for supporting the optical member 3 made of a material having excellent biocompatibility such as pure titanium, a titanium alloy or tantalum, and has a truncated dome shape as a whole as shown in FIG. It has a through hole 2b.

The optical member 3 is made of a light-transmitting material such as single-crystal alumina or a synthetic resin material such as PMMA or silicon, which has no harm to the living body. As shown in FIGS. 3b has a dome-shaped disk shape having an optically appropriate curvature, and as shown in FIG. 3, the side surface 3c is rearwardly opened along the circumference so as to fit into the center hole 2a of the support member 2. 4d, or a groove 3e for inserting a part of the support member 2 as shown in FIG.

The artificial cornea 1 according to the present invention comprises the support member 2 and the optical member 3 described above. The optical member 3 is press-fitted into the central hole 2a from the front side or the rear side of the support member 2, and the step portion 3d or The optical member 3 is fitted and fixed in the central hole 2a by the groove 3e.

In the artificial cornea 1 thus configured, since the supporting member 2 is made of the above-mentioned biocompatible metal material, the supporting member 2 is well adapted to the corneal tissue, and no gap is formed between the cornea K and the artificial cornea. Also, since it has a truncated dome shape, it conforms to the shape of the cornea K, and a part of the main body 2c does not break through the cornea K and is exposed to the outside. (See FIG. 2) without causing pancreatitis. The curvature R of the support member 2 shown in FIG.
It is preferable that the curvature R is approximately 6 to 9 mm by approximating the curvature of 7 to 8 mm.

Further, since the thickness of the support member 2 can be made sufficiently smaller than that of the cornea K by using the above-mentioned metal material, there is almost no surgical invasion, and complications such as pancreatitis do not occur. The artificial cornea 1 can be stably implanted in the cornea K. In addition, it is preferable that the thickness of the support member 2 is 0.03 to 0.3 mm. When the thickness is smaller than 0.03 mm, the support member 2 is distorted or deformed due to the movement of the eyelids, so that a gap is formed between the support member 2 and the cornea K. When the thickness is larger than 0.3 mm, the support member 2 is removed. The interposed cornea K cannot hold the artificial cornea 1 firmly. Therefore, a gap is formed between the cornea K and the cornea K due to the movement of the eyelids, etc., from which bacteria enter the anterior chamber and cause pancreatitis. There is fear.

Further, the through hole 2b is formed so that the cornea K
In addition, the dehydration in the front layer F caused by the separation into the rear layer N and the resulting malnutrition are prevented, and the opening rate of the main body 2c is suitably 20 to 70%. If the porosity is less than 20%, the cornea K becomes cloudy due to dehydration and accompanying malnutrition in the anterior layer F of the cornea K, and if it exceeds 70%, the support member 2 cannot be formed into a truncated dome shape. .

A coating layer (not shown) made of a biocompatible material such as hydroxyapatite or collagen may be provided on the surface of the main body 2c of the support member 2. As shown in FIG. 2, a suture thread T is inserted into the through hole 2b.
Through this, the artificial cornea 1 can be firmly fixed to the cornea K.

Next, a method for producing the artificial cornea 1 of the present invention will be described. In manufacturing the artificial cornea 1, the support member 2 is first formed with a central hole 2a and a through hole 2b shown in FIG. 5 by a known photo-etching method on a sheet-like thin plate having a relatively large area made of the above-described metal material. A large number of the disc-shaped support members 2 are formed at a time, and further press-formed on the disc-shaped support member 2 to form a truncated dome-shaped support member having a curvature R close to the curvature of the cornea K. 2 is produced.

In the above press molding, a lower mold 4 and an upper mold 5 shown in FIG. 6 are used in combination, and the lower mold 4 is slightly mounted on the base 4a due to the curvature of the supporting member 2 to be formed. A cylindrical portion 4b having a small curvature and having a truncated dome shape having an optimum size and shape is provided, and a horizontal cross-sectional shape can be inserted through the central portion 2a of the support member 2 from the positive portion 4b. The upper die 5 has a truncated dome-shaped negative mold part 5a corresponding to the positive mold part 4b on the lower end face 5c and an upper end of the negative mold part 5a. A cylindrical insertion hole 5b corresponding to the insertion rod 4c is formed in the vertical direction from the part 5e, and the upper part is inserted into the press machine C.

First, the support member 2 is loaded around the insertion rod 4c, and then the upper mold 5 is lowered so that the insertion rod 4c is inserted into the insertion hole 5b. 7, the support member 2 is pressed against the inner wall 5d of the positive mold portion 4b and the negative mold portion 5a, and the support member 2 is formed into a truncated dome shape having a curvature R approximating the curvature of the cornea K. I do.

The through-holes 2b of the support member 2 are rounded at the corners in order to disperse the stress at the time of press forming. Also, as shown in FIG. It is preferable that the through holes 2b of the adjacent rows do not overlap in the radial direction and are arranged alternately.

According to the above-described manufacturing method, the central hole 2a for fitting the optical member 3 to the extremely thin plate made of the above-mentioned metal is provided.
And the through-hole 2b are formed with a larger opening ratio, and an artificial cornea having the support member 2 formed in a truncated dome shape can be manufactured.

Example 1 The through hole 2b of the supporting member 2 made of pure titanium shown in FIG. 1 was changed in size, and the thickness was 0.3 mm and the porosity of the main body 2c was as shown in Table 1 by the above-described manufacturing method. Nine kinds of disc-shaped support members 2 were produced, and further, an attempt was made to form a truncated dome shape having a curvature R = 8 mm. Table 1 shows the results.

[0024]

[Table 1]

As is clear from Table 1, when the opening ratio of the main body 2c of the support member 2 exceeds 70%, the main body 2c
Is too small, the main body 2c is deformed even if a slight stress is applied when the support member 2 is detached from the lower mold 4, and cannot be formed into a truncated dome shape.

A support member 2 formed in a truncated dome shape and an optical member 3 made of PMMA as shown in FIG.
The artificial cornea 1 was fixed in the cornea K of a rabbit by passing a suture through the through-hole 2b as shown in FIG. 2 and observed for 6 months for the presence or absence of clouding of the cornea. Table 1 shows the results.

As is clear from Table 1, when the opening ratio of the main body 2c of the support member 2 is smaller than 20%, the cornea K becomes cloudy.

From the above, it has been found that the porosity of the main body 2c of the support member 2 is preferably 20 to 70%.

Example 2 As shown in FIG. 4, the thickness is as shown in Table 2, the main body 2c has an opening ratio of 60%, the curvature R = 7 mm, the support member 2 made of tantalum, and the optical member made of single-crystal alumina. The artificial cornea 1 composed of the member 3 is manufactured by the method described above, and these are fixed in the cornea K of the rabbit through the suture T through the through hole 2b as shown in FIG. The occurrence of flame was observed. Table 2 shows the results.

[0030]

[Table 2]

As is clear from Table 2, it was found that the thickness of the supporting member 2 is preferably 0.03 to 0.3 mm.

Example 3 As shown in FIG. 3, the thickness of the support member 2 is 0.1 mm, the opening ratio of the main body 2c is 55%, and the curvature R is as shown in Table 3. The artificial cornea 1 composed of the optical member 3 is manufactured by the method described above,
These are inserted into the cornea K of the rabbit as shown in FIG.
Then, it was fixed through a suture thread T, and it was observed whether or not a part of the main body 2c of the support member 2 was exposed on the surface of the cornea K for 6 months. Table 3 shows the results.

[0033]

[Table 3]

As is clear from Table 3, the curvature R of the supporting member 2 is preferably 6 to 9 mm.

[0035]

According to the present invention, since the supporting member is formed of a biocompatible metal material such as titanium or tantalum, the supporting member is well adapted to the corneal tissue and no gap is formed between the supporting member and the cornea. In addition, because of the truncated dome shape, the shape conforms to the cornea, and a part of the main body of the support member does not break through the cornea and is exposed to the outside, so that bacteria enter the anterior chamber and occulitis Can provide an artificial cornea that does not cause illness, which is exactly what brings light to humanity.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an artificial cornea according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the artificial cornea according to the embodiment of the present invention is implanted in the cornea.

FIG. 3 is a central sectional view of an artificial cornea according to an embodiment of the present invention.

FIG. 4 is a sectional view of an optical member constituting an artificial cornea according to another embodiment of the present invention.

FIG. 5 is a plan view of a support member constituting the artificial cornea according to the present invention.

FIG. 6 is a sectional side view showing a main part of an upper mold and a lower mold used in the method of manufacturing an artificial cornea according to the embodiment of the present invention.

FIG. 7 is a cross-sectional side view of a main part showing an upper mold and a lower mold used in the method of manufacturing an artificial cornea according to the embodiment of the present invention.

FIG. 8 is a perspective view showing an artificial cornea according to a conventional example.

FIG. 9 is a perspective view showing an artificial cornea according to a conventional example.

[Explanation of symbols]

 K cornea F anterior layer N posterior layer C press machine S anterior chamber W aqueous humor 1 artificial cornea 2 support member 3 optical member 4 lower mold 5 upper mold 2a central hole 2b through hole 2c body

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Shintaro Takahara (56) References JP-A-4-158859 (JP, A) JP-T-3-501214 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ A61L 27/00-27/60 A61F 2/00-2/48

Claims (2)

(57) [Claims] An optical member made of a translucent material which is not harmful to the living body to replace the lost cornea or a biocompatible material such as pure titanium, titanium alloy or tantalum. An artificial cornea which is fitted in a central hole formed in a support member having a thickness of 0.03 to 0.3 mm and made of a metal material having a thickness of 0.03 to 0.3 mm. An artificial cornea having a head dome shape, wherein a plurality of through-holes are formed at an opening ratio of 20 to 70% in a main body of the supporting material. 2. A thin disk made of a metal material is provided with a center hole and a plurality of through holes by photoetching to form a disk-shaped support member, and the support member is press-formed into a truncated dome shape. 2. The method for producing an artificial cornea according to claim 1 , further comprising a step of fitting an optical member into a central hole of the support member.