JP3318192B2 - Intraocular lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intraocular lens for implantation into an eye instead of a crystalline lens, and more particularly, to a deformable intraocular lens which can be deformed when inserted into the eye and inserted from a small incision. Related to.

[0002]

2. Description of the Related Art Conventionally, there has been known a treatment method in which a diseased lens of a cataract patient or the like is extracted and an artificially manufactured intraocular lens is inserted in place of the extracted lens. In an intraocular lens insertion operation, it is said that the smaller the incision wound to be inserted to insert the intraocular lens, the sooner the wound is recovered after treatment, and the less postoperative astigmatism and sac opacity are less likely to occur.
Therefore, in order to reduce the incision when inserting the intraocular lens, a deformable soft intraocular lens that can be inserted even from an incision smaller than the lens diameter of the intraocular lens has been proposed. As a proposed soft intraocular lens, a lens made of a material having relatively high biocompatibility such as a silicone resin, a non-hydrous acrylic resin, and a hydrous hydroxyethyl methacrylate is known.

[0003]

However, an intraocular lens made of a silicone resin has the advantage that it can be easily folded and has a high strength. It can damage the endothelial cell layer and is difficult to handle in the eye. Further, since the refractive index is relatively low, the thickness of the lens becomes relatively thick. Further, there is a problem that when moisture adheres to the surface, the surface slips and becomes very difficult to handle.
For example, during surgery, a large amount of water is used to clean the surgical eye, and water may adhere to the eye by accidental dropping.

[0004] Intraocular lenses made of non-water-containing acrylic resin have relatively strong adhesiveness on the surface of the lens. When the intraocular lens is bent and deformed, both ends of the lens are inserted when the lens is inserted into the eye. It has a problem that it is difficult to handle because it sticks or sticks to the forceps for insertion.

[0005] Hydroxyethyl methacrylate (hereinafter referred to as HEMA), which is water-containing, has been tried to be used as a folding lens from an early stage because of its flexibility. Has a problem that it is difficult to maintain the shape. Also, due to its relatively brittle properties, there is a risk that the lens will tear during surgery.

In view of the above problems, the present invention provides an intraocular lens having high biocompatibility, easy handling of the lens when the lens is inserted, relatively gentle opening in the eye, and sufficient strength. The purpose is to do.

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by having the following arrangement.

(1) In an intraocular lens to be inserted into the eye after lens extraction, a material of an optical part of the intraocular lens is
Hydroxyethyl methacrylate (80-90 weight ratio)
%) , Ethyl methacrylate (compounding ratio 8 to 20 % by weight)
%) And a crosslinking agent (compounding ratio 0 to 10% by weight).
And one end of the optic of the intraocular lens
Is placed on the measuring surface of the weighing scale, and the other end is sandwiched between tweezers.
Weight scale when folded into U-shape just before contact
The heap is about 50-150g, and both ends touch with tweezers
And folded in U-shape until just before
The release speed for restoring the shape to the original shape is about 1 to 72 seconds.

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS HEMA has high biocompatibility, good lens surface properties, and is resistant to the impact of a YAG laser for treating posterior capsule opacity, which is a secondary cataract, and is hydrophilic. It has advantages such as less contact injury to the cornea. With HEMA as the main component, it is easy to polymerize with HEMA and has high biocompatibility in order to control the problem of being too soft, which is a problem, and to give appropriate hardness and strength. Methacrylic acid ester was used as a copolymer component.

[0015] Then evaluation method of manufacturing intraocular lenses are described. An intraocular lens is composed of an optical part and a support part, and a one-piece lens manufactured integrally with the optical part and the support part and a three-piece lens manufactured separately from the optical part and the support part are known. The prepared intraocular lens was prepared only as an optical part without a supporting part. A lens having a lens diameter of 6.0 mm, a radius of curvature of the lens surface of 8.0 mm, and an edge thickness of 0.35 mm was prepared and subjected to autoclave sterilization for about 30 minutes and sufficiently hydrated. The release rate was measured.

The force required for bending is an important indicator of the force required to deform the lens. The measurement method was performed by reading one end of the intraocular lens on the measurement surface of the balance and bending the other end into a U-shape with tweezers. The amount of deformation at the time of measurement was such that the lens was deformed until immediately before both ends of the lens were in contact with each other, and the scale of the scale at this amount of deformation was measured as the force required for bending.

The release speed is a guide to the open state of the lens in the eye. For the measurement, sandwich the lens with the amount of deformation that touches both ends with tweezers, put it in water at about 25 ° C while maintaining the deformation, open the tweezers in the water to release the lens deformation, and return to the original shape The restoration time until returning was measured. Confirmation of the return to the original shape was made by visual inspection.

[0018] The compounding ratio <Experimental Example 1> FIG 1 HEMA: a copolymer component = 80: shows the experimental results when the 20. In this example, among the methacrylates, n-butyl methacrylate (hereinafter, referred to as n-BMA), ethyl methacrylate (hereinafter, referred to as EMA), and methyl methacrylate (hereinafter, referred to as MMA) were used as the copolymer components. Three types were selected. If the substituent has a large number of carbon atoms, it tends to be chemically unstable. Therefore, a copolymer component having a small number of carbon atoms in the substituent is preferable. To briefly list the characteristics of the three types of methacrylate esters as monomers, n-BMA has high elasticity due to the steric structure of the butyl group, EMA has tenacity in strength, and MMA has hard and brittle characteristics. .

[0019] Given as polymer properties with these monomers, as can be seen from the experimental results of FIG. 1, H
It can be seen that the composition obtained by blending n-BMA with EMA immediately returned to the original shape, as can be seen from the fact that the release speed is marked as 0 seconds. This is a reaction similar to that of the silicone resin type, and shows that it is very difficult to handle in the eye.

Further, those obtained by blending MMA to HEMA is release rate conversely very long, the force required to bend a lot necessary, it can be seen that it is difficult to deform. The long release speed itself does not affect the ease of handling of the lens in the eye, but too long a release speed may require a long operation time or reduce the stability of the lens in the eye. This will also lead to closing the incision without confirmation.

[0021] obtained by blending EMA to HEMA is, n-
It shows an intermediate value between BMA and MMA, and it can be seen that the release speed is relatively gentle and the deformation can be performed relatively easily. Furthermore, it has the toughness of EMA as a characteristic, and has sufficient strength as compared with conventional HEMA.

[0022] <Experimental Example 2> Next, we and HEMA, 3 kinds of experiments good results by changing the mixing ratio of the resulting EMA in methacrylic acid ester. FIG. 2 shows the experimental results. In FIG. 2, H
Experiments were carried out with five kinds of compounding ratios while changing the EMA between 70 and 90% by weight. As the copolymerization component, EMA is 8
To 30% by weight, and ethylene glycol dimethacrylate (hereinafter referred to as EGDMA) as a cross-linking agent was added at a ratio of 0 to 2% by weight.

A crosslinking agent is added to strengthen the chemical bond and to provide stability. Instead of EGDMA, 4-vinylbenzene (meth) acrylate, 3-vinylbenzene (meth) acrylate, diethylene glycol di (meth) Acrylate, triethylene glycol di (meth)
Well-known materials such as acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, allyl (meth) acrylate, and vinyl (meth) acrylate can be used.

As shown in the experimental results of FIG .
When the mixing ratio of HEMA is reduced as shown in FIG. 1, the force required for bending is increased, the release speed is reduced, and the MMA in FIG.
Is similar to the behavior when polymerized. vice versa,
When the compounding ratio of HEMA is increased as in compounding ratio 2 or 4, the force required for bending is reduced and the release speed is increased. Further, it can be seen that the force required for bending is substantially proportional to the mixing ratio of HEMA and EMA.

In the case of the compounding ratio 3 or 5 to which the crosslinking agent EGDMA was added, the compounding ratio 2 or 4 in the case where no crosslinking agent was added was used.
It can be seen that the force required for bending tends to increase and the release speed tends to increase as compared to

The deformable intraocular lens, which is the easiest to handle in intraocular lens insertion surgery, requires a bending force of about 50 to
Since the release rate is about 150 g and the release speed is about several seconds to several tens of seconds, it can be seen from FIG. 1 and FIG. 2 that the optimum compounding ratio obtained is about 80 to 90% by weight of HEMA. However, in comparison with a conventional intraocular lens of this type, if the composition ratio of HEMA is 60 to 95% by weight, some advantage is recognized.

In the present embodiment, the description has been made only on the basis of several kinds of compounding ratios.
However, it is possible to add up to about 10% by weight as needed in relation to the mixing ratio of HEMA.

[0028]

As described above, according to the present invention, an intraocular lens having high biocompatibility, easy handling of the lens when the lens is inserted, relatively mild behavior in the eye, and sufficient strength is provided. Ru can be obtained.

[Brief description of the drawings]

FIG. 1 is an experimental result when a methacrylic acid ester is polymerized on HEMA.

FIG. 2 is an experimental result when HEMA is polymerized with EMA.

Claims (1)

(57) [Claims] 1. An intraocular lens to be inserted into the eye after lens extraction, wherein the material of the optical part of the intraocular lens is hydroxyethyl methacrylate (compounding ratio: 80 to 90% by weight).
%) , Ethyl methacrylate (compounding ratio 8 to 20 % by weight)
%) And a crosslinking agent (compounding ratio 0 to 10% by weight).
And one end of the optic of the intraocular lens
Is placed on the measuring surface of the weighing scale, and the other end is sandwiched between tweezers.
Weight scale when folded into U-shape just before contact
The heap is about 50-150g, and both ends touch with tweezers
And folded in U-shape until just before
An intraocular lens characterized in that the release speed for restoring to the original shape when it is released is about 1 to 72 seconds.