JPH09218382A - Multifocal contact lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to sufficiently supply oxygen to the tissues of the eyes covered with lenses by constituting the lenses of far sight parts and near sight parts and providing the lenses with holes communicating the rear part surfaces and the front part surfaces with each other, thereby communicating the boundaries between the eyes and the lenses with the free atm. SOLUTION: The bifocal lens 2 consists of the far sight part 4 and the near sight part 6. The low part end 8 is slightly cut at the front end to maintain the adequate positioning of the lens 2. The lower part of the near sight part 6 is provided with three pieces of the holes 10 having about 0.5mm diameter. The space filled with the tears between the rear part surface of the lens 2 and the cornea 12 and the sclera 16 is communicated with the free atm. through these holes, by which the approach of the oxygen-contg. air to the tissues of the eyes covered with the contact lens is accelerated. The visual axis VA of the eyes pass the far sight part 4 of the lens 2. The lens 2 is pushed up to the eye staring the lower side in the near sight position, by which the visual axis VA is passed through the near sight part 6 of the lens 2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a multifocal contact lens.

[0002]

BACKGROUND OF THE INVENTION Multifocal contact lenses, and more particularly bifocal contact lenses, are as free to use as single-focal or single-magnification contact lenses, unless there are significant problems with prior art contact lenses of this kind. Will be done. For near vision, the visual axis of the eye must pass through the lower part of the lens, and for far vision, the visual axis must pass through the upper part of the lens, so to switch from one visual field to the other. It is clear that relative movement must occur between the eye and the lens. In fact, when staring downwards for near vision, the lens is pushed up by the lower eyelid, while returning to far vision is primarily due to gravity.

However, especially in soft contact lenses of larger diameter than the cornea, when the above-mentioned relative movement occurs, a slight amount between the posterior surface of the adhesive lens and the corneal-corneal-capsular part of the eye. The space changes, which causes a certain amount of tears trapped in the space to undergo a change in pressure that causes resistance to movement, that is, lower lid lifting, which causes pain to the wearer. If not, it is likely to cause great discomfort and cause insufficient exercise.

In one type of prior art bifocal lens known as "ballasted", the lower, truncated portion of the lens is made very thick, thereby providing a constant pressure on the lower eyelid. Attempts have been made to overcome this problem by reducing While this improves some of the above problems, it also creates new problems. That is, the thick cross-section of the ballasted lens blocks the oxygen supply from the air to the corneal and capsular regions, thus preventing proper metabolism of these tissues.

[0005]

Accordingly, one of the objects of the present invention is to provide a transmission passage between the eye / lens interface and the free atmosphere to provide oxygen supply to the lens-covered eye tissue. It is to provide a multifocal contact lens that enhances.

[0006]

According to the invention, at least one of a rear surface and a front surface is formed, which comprises a far field portion and a near field portion, the rear surface and the front surface communicating with each other. The above object is achieved by providing a multifocal contact lens characterized in that it comprises two holes.

[0007]

For a better understanding of the invention, the invention is described with reference to the following drawings in connection with certain preferred embodiments. With particular reference to the detailed drawings, the details shown are shown by way of example and for the purpose of illustratively describing the preferred embodiments of the invention and are believed to be the most useful. As
And assert that the principles and concepts of the invention are presented as readily understandable. In this regard, no more structural details than are necessary for an essential understanding of the invention are shown, and the description accompanying the drawings illustrates how some aspects of the invention may be practiced. It is clear to those skilled in the art whether it can be embodied in.

In the drawings, FIG. 1 is a front view of a bifocal contact lens according to the present invention, FIG. 2 is a sectional view of the lens of FIG. 1, and FIG. 3 is a schematic view of the outline of the human eye. 4 shows the relative positions of the cornea and the lens with respect to the far field, and FIG. 5 shows the relative positions of the cornea and the lens with respect to the near field. Furthermore, FIG. 6 shows the position of the lens on the eye for the far field, and FIG. 7 shows the position of the lens for the near field.

Referring to the drawings, FIGS. 1 and 2 show a bifocal lens 2 consisting of a far field portion 4 and a near field portion 6. The lower end 8 is slightly truncated in a manner known per se and serves to maintain the required proper positioning of the lens 2.

Below the near-field portion 6, a diameter of about 0.5 mm
Three small holes 10 are shown. A tear-filled space between the posterior surface of the lens 2 and the cornea 12 and capsular membrane 16 communicates with free air through these holes. This prevents the development of overpressure or underpressure that impairs lens movement in both directions and also facilitates the access of oxygen-containing air to the tissue of the eye covered with contact lenses.

The outline of the portion of the human eye is shown diagrammatically in FIG. 3, with the cornea 12, the limbus 14 and the capsular membrane 16.
It is shown. The position of the lens 2 with respect to the cornea 12 in the far field position is clearly shown in FIG. 4, with the visual axis VA of the eye passing through the far field portion 4 of the lens 2.

In FIG. 5, the lens 2 is pushed up against the eye staring downwards, so that the visual axis VA passes through the near-field portion 6 of the lens 2. Front views of the position of the contact lens 2 on the eye for the far field and the near field are shown in FIGS. 6 and 7, respectively.

There may be fewer or more than three holes 10 and the holes 10 are shown as being located in a straight line, but along a circle or in any other curved line. May be located along.

It is to be understood that the present invention is not limited to the details of the embodiments described above, and that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. It will be apparent to those skilled in the art. The embodiments of the present invention are therefore to be regarded in all respects as illustrative and not restrictive, the scope of the present invention being indicated not by the above description but by the accompanying drawings. It is intended that the present invention cover all modifications as indicated by the appended claims and within the meaning and range of equivalency of the claims.

[0015]

According to the present invention, since a multifocal contact lens having a far-field portion and a near-field portion is provided with at least one hole whose rear surface and front surface communicate with each other, an eye covered with the lens is provided. Sufficient oxygen is constantly supplied to the tissues, and the proper metabolism of the tissues is promoted.

Also, when the line of sight is switched from the far field to the near field or from the near field to the far field, the tear between the posterior surface of the lens and the eye tissue such as the cornea due to the relative movement between the eyeball and the lens. Even if the size of the space filled with is changed, the pressure in the internal space does not change greatly.
That is, no excessive pressure or insufficient pressure that impairs the relative movement of the lens with respect to the eyeball occurs, and the wearer of the lens can switch the line of sight extremely smoothly without feeling pain or discomfort.

[Brief description of drawings]

FIG. 1 is a front view of a bifocal contact lens according to the present invention.

2 is a cross-sectional view of the lens of FIG.

FIG. 3 is a schematic diagram of the outline of the human eye.

FIG. 4 shows the relative position of the cornea and lens with respect to the far field.

FIG. 5 shows the relative position of the cornea and lens with respect to the near field.

FIG. 6 shows the position of the lens on the eye relative to the far field.

FIG. 7 shows the position of the lens relative to the near field.

[Explanation of symbols]

 2: Multifocal lens 4: Far-field part 6: Near-field part 8: Lower edge 10: Small hole 12: Corneal 14: Corneal rim 16: Capsular VA: Visual axis

Claims (3)

[Claims] 1. A back surface and a front surface, wherein there is at least one hole comprising a far field portion and a near field portion, said rear surface and said front surface communicating with each other. Multifocal contact lens. 2. The contact lens according to claim 1, wherein a truncated lower end is present in the near-field portion. 3. The contact lens according to claim 1, wherein a plurality of holes are present in the lower portion of the near-field portion.