JPS62153932A - Contact lens - Google Patents

Abstract

PURPOSE:To permit long-term continuous wearing of a contact lens by forming the central part of the lens to a shape bulging to the front face side of the lens from the peripheral part of the lens and forming at least one through-hole at the central part of the lens so that oxygen is substantially supplied to the cornea. CONSTITUTION:The contact lens 10 is integrally formed with the central part 12 consisting of a hard synthetic resin stock and the peripheral part 14 of the lens consisting of a soft synthetic resin stock by a casting method and is bored with the three through-holes 16 in the central part 12 of the lens after molding. The lens 10 is so mounted that the peripheral part 14 thereof contacts the surface of the sclera 22 of the eyeball 20. Since the central part 12 of the lens is formed approximately equal to the radius of curvature of the cornea 24, a spacing 26 between the central part 12 of the lens and the cornea 24 is made approximately equidistant. Tears are substantially retained in the spacing 26 and since the spacing 26 is held communicated with the front face side of the lens through the through-holes 16, the tear can move freely in and out of the spacing. The oxygen is thereby substantially supplied to the cornea 24.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a contact lens, and more particularly to a contact lens that can be worn continuously for a long period of time.

[Prior Art] Supplying oxygen to the cornea is essential to enable long-term continuous wear of contact lenses. Contact lenses are broadly divided into hard and soft types, and lenses made of polymethyl methacrylate, which is the most common type of hard contact lens, have excellent optical properties and are easy to handle, so they are often used for fortune-telling. However, it has almost no water content and no oxygen permeability. Oxygen is supplied to the cornea through the lachrymal fluid interposed between the corneal surface and the lens. However, in the case of the above-mentioned hard lenses, the lachrymal fluid interposed between the lens and the cornea does not circulate easily, making it difficult to wear. The time limit is about one day.

Also, among soft contact lenses, silicone-based non-water-containing lenses have less of a foreign body sensation than the above-mentioned hard contact lenses, but they tend to adhere more closely to the cornea, which allows for the supply of lachrymal fluid between the lens and the cornea. is not carried out sufficiently, and the wearing time becomes even shorter.

On the other hand, in recent years, soft contact lenses with high water content and high oxygen permeability have been developed, and the wearing time has been significantly improved.

[Problem to be Solved by the Invention 1] However, soft contact lenses with a high water content have uneven swelling rates due to hydration during manufacture, and are susceptible to dirt during use, resulting in hygiene problems. There are problems such as cumbersome management.

These problems are essential problems that cannot be avoided to some extent since the water content is high. Furthermore, high water content soft contact lenses have inferior optical properties compared to hard contact lenses. Therefore, it is desirable to supply oxygen to the cornea by means other than reducing the water content.

In order to supply oxygen to the cornea, it is necessary to exchange tear fluid between the corneal surface and the lens, and for this purpose, a hole is provided in the contact lens and oxygen is supplied through this hole. Attempts have also been made in the past. However, in the conventional method, the edge of the drilled hole comes into direct contact with the cornea, which poses a problem of irritating the cornea.

An object of the present invention is to eliminate the drawbacks of the prior art described above, provide a contact lens that provides sufficient oxygen supply to the cornea and can be worn continuously for a long period of time.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a central portion of the lens made of a hard synthetic resin material, and a soft synthetic resin material formed approximately concentrically around the central portion of the lens. The periphery of the lens constitutes a contact lens. The central portion of the lens was shaped to bulge toward the front surface of the lens from the peripheral portion of the lens, and at least one through hole was formed in the central portion of the lens.

The appearance of the contact lens of the present invention is similar to conventional gonio-electromembrane lenses, but in the present invention, the lens has a through hole in the center and the peripheral part of the lens is made of a soft synthetic I4 resin material. The difference is that there are

The peripheral part of the lens is the part that supports the contact lens on the electrolytic film of the eyeball, and preferably has a radius of curvature close to the radius of curvature of the electrolytic film (generally is formed by approximately 12 to 13+n). The lens diameter including the lens periphery is generally 15
It is about 18 mm.

The central part of the lens functions as a normal lens, and has a diameter that is approximately the same as or slightly larger than the diameter of the cornea that will be worn (generally about 12 to 15 mm). It is formed into a bulged shape.

As the material for the central part of the lens, a general synthetic resin for hard contact lenses, such as polymethyl methacrylate, can be used, and as the material for the peripheral part of the lens, a conventional synthetic resin for general soft contact lenses, such as N, can be used. - Vinylpyrrolidone, hydroxyalkyl methacrylate, silicone resin, etc. can be used. The central portion of the lens and the peripheral portion of the lens can be integrally molded by, for example, a cast molding method.

At least one through hole is formed in the center of the lens,
The number of through holes can be appropriately selected depending on the hole diameter. The pore diameter is usually preferably in the range of 0.1 to 0.4ia, and the number of through holes is usually about 1 to 10.

[Function] When the contact lens of the present invention having the above structure is worn, it is supported by the flexible peripheral part of the lens on the electrical membrane around the cornea, and the central part of the lens is hard, so it maintains a predetermined shape.
It is separated from the cornea without contacting it. Therefore, a sufficient gap is created between the lens surface and the cornea to hold the tear fluid, and this gap communicates with the front surface of the lens through a hole formed in the center of the lens, so that the tear fluid can be retained. can freely flow from the front side of the lens into the gap and vice versa. In addition, at this time, if pressing force is applied intermittently to the lens due to blinking, etc., the distance between the center of the lens and the cornea changes, and the above volume increases or decreases accordingly, so the tear fluid in the gap is forced to flow. It will be replaced by

Oxygen is supplied to the cornea through lachrymal fluid, so the above action provides sufficient Il! to the cornea. cable supply will be carried out.

[Example] FIGS. 1 and 2 are a front view and a central vertical cross-sectional view, respectively, showing an example of a contact lens according to the present invention.

This contact lens 10 is made by integrally molding a lens central portion 12 made of a hard synthetic resin material and a lens peripheral portion 14 made of a soft synthetic resin material by a casting method,
After molding, three through holes 16 are bored in the central portion 12 of the lens.

In this embodiment, the lens peripheral part 14, which is formed concentrically around the lens center part 12, is formed to form a part of a spherical surface having a radius of curvature that is approximately the same as Ill of the eyeball to be worn.

As shown in FIG. 2, the lens central portion 12 is formed to have a radius of curvature smaller than the −F radius of curvature of the lens peripheral portion 14, and has a shape that bulges toward the front side of the lens.

Since the lens center portion 12 is a portion that functions as a lens, it is made of transparent hard synthetic resin and can be formed into a convex lens or a convex lens depending on the purpose.
It is formed into a desired lens shape such as a concave lens. On the other hand, since the lens peripheral part 14 is a part for supporting the contact lens 10 on the Ill, it is only necessary that it is flexible and formed along the electrical film surface, and it does not need to be transparent.

Next, the manner of use and operation of this embodiment will be explained based on FIG. 3.

FIG. 3 is a horizontal cross-sectional view of the anterior part of the eyeball showing a state in which the contact lens 10 is attached to the eyeball.
It is attached so as to be in contact with 2. The central portion 12 of the lens does not come into contact with the cornea 24 but is separated from it, creating a gap 26 between the two. Although the gap 26 is emphasized in the drawing for clarity, in reality, the lens central portion 12 is formed to be approximately equal to the radius of curvature of the cornea 24, so that the lens central portion 12 and the cornea 24 are The gaps 26 are approximately equally spaced.

This gap 26 holds sufficient lachrymal fluid, and since this gap 26 is in communication with the front surface of the lens through the through hole 16, the lachrymal fluid can freely enter and exit, and the corner l
It is possible to supply sufficient oxygen to I24.

In this embodiment, the lens peripheral portion 14 is formed as a part of a spherical surface, but since it is flexible, it may be formed simply as a flat flange shape, or if the radius of curvature is smaller in the cross-sectional shape. It may also be formed as a small piece.

[Effect of the invention] As explained above, the contact lens according to the present invention has the following effects:
When worn, the flexible peripheral part of the lens comes into contact with the electromembrane part of the eyeball, and this part supports the lens and prevents the lens from coming into contact with the corneal surface, so it does not irritate the cornea and is easy to wear. There is also less chance of the cornea being damaged by dust or the like. Moreover, since the lachrymal fluid that fills the gap between the lens and the cornea enters and exits through the pores, sufficient oxygen can be supplied to the cornea, making it possible to wear the lens continuously for a long period of time.

[Brief explanation of drawings]

Fig. 1 is a front view showing an embodiment of the Funtact lens according to the present invention, Fig. 2 is a longitudinal sectional view at the center thereof, and Fig. 3 is a horizontal sectional view of the front part of the eyeball showing the usage state of the same embodiment. be.

Claims (1)

[Claims] The lens has a central portion made of a hard synthetic resin material, and a peripheral lens portion made of a soft synthetic resin material formed approximately concentrically around the central portion of the lens, and the central portion of the lens is closer to the peripheral portion of the lens than the peripheral portion of the lens. A contact lens characterized by bulging toward the front side and having at least one through hole in the center of the lens.