JP2007195818A - Contact lens for orthokeratology - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact lens for orthokeratology, which provides stable effects of restoring vision by feeding a tear fluid between the contact lens and the surface of a cornea when a user wears the contact lens and by preventing the contact lens from being fixed to a cornea. <P>SOLUTION: The contact lens 10 for orthokeratology reshapes the cornea to correct myopia by wearing the contact lens 10 at bed time and is taken off during the time other than the bed time to stay with naked eyes. A recess 13 for acquiring a habit is formed on the reverse side of the central part 11 of the contact lens 10, and an introducing hole 15 penetrated from the surface to the reverse side is provided at the peripheral part 12 so that the tear fluid is led to the reverse side of the peripheral part 12 through the introducing hole 15 while the contact lens 10 is worn. The introducing holes 15 are provided circumferentially at four places at intervals of 90 degrees. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an orthokeratology contact lens that is worn on the eyes at bedtime, corrects myopia by changing the shape of the cornea during bedtime, and is removed with the naked eye in the next morning.

A normal contact lens consists of a concave lens, and corrects myopia by putting it on eyes. On the other hand, orthokeratology contact lenses can be worn when sleeping at night to correct the shape of the cornea during sleep, and when removed when waking up in the morning, visual acuity temporarily recovers, and during the day, you can spend with the naked eye. It is something that can be done. That is, this orthokeratology contact lens is a hard contact lens for high oxygen permeability having a special shape that changes the shape of the cornea surface. The present inventor previously proposed an invention related to an eye mask for improving dry eye symptoms, and proposed to use this orthokeratology contact lens to correct myopia (Patent Document 1). reference).
JP 2004-254994 A (second page and FIG. 2)

  However, since the back surface of the outer periphery of the orthokeratology contact lens is in close contact with the corneal surface, tear fluid is not replenished in that portion, and the state remains for a long time during bedtime. May cause problems such as corneal erosion and unstable eyesight. In particular, when a person with symptoms such as dry eye wears an orthokeratology contact lens, there are many such problems. In the technique described in Patent Document 1, although moisture on the front side of the orthokeratology contact lens is retained, the back side is not sufficiently replenished with moisture on the front side, and the above-described problems occur. It was not always eliminated.

  The present invention has been made paying attention to such problems existing in the prior art, and the object of the present invention is to supply tear fluid between the cornea surface and the cornea when it is worn on the eye. An object of the present invention is to provide an orthokeratology contact lens capable of suppressing sticking and obtaining a stable visual acuity recovery effect.

  In order to achieve the above object, the orthokeratology contact lens of the invention according to claim 1 is used for correcting myopia by changing the shape of the cornea when worn at bedtime, and removing it at non-sleep time to spend with naked eyes. An orthokeratology contact lens, wherein a concave portion is formed on the back surface of the central portion, and an introduction hole that penetrates from the front surface to the rear surface in the outer peripheral portion or an introduction groove that communicates from the outer peripheral edge to the concave portion for caulking on the rear surface. And the lacrimal fluid is guided to the back surface of the outer peripheral portion through the introduction hole or the introduction groove in the mounted state.

  An orthokeratology contact lens according to a second aspect of the invention is characterized in that, in the invention according to the first aspect, the introduction hole or introduction groove is provided at a plurality of locations.

  An orthokeratology contact lens according to a third aspect of the invention is characterized in that, in the invention according to the first or second aspect, the introduction hole or the introduction groove is provided at an opposing position. .

According to the present invention, the following effects can be exhibited.
In the orthokeratology contact lens according to the first aspect of the present invention, a concave portion for forming is formed on the back surface of the central portion, and an introduction hole penetrating from the front surface to the back surface is formed on the outer peripheral portion, or the concave portion for bonding is formed on the back surface from the outer peripheral edge. An introductory groove that communicates is provided. For this reason, lacrimal fluid is guided to the back surface of the outer peripheral portion through the introduction hole or the introduction groove in the wearing state. Therefore, when an orthokeratology contact lens is attached to the eye, tear fluid is replenished between the back surface of the outer peripheral portion and the cornea surface, and sticking of the orthokeratology contact lens to the cornea is suppressed, and a stable visual acuity recovery effect is achieved. Obtainable.

  In the orthokeratology contact lens according to the second aspect of the present invention, the introduction hole or the introduction groove is provided at a plurality of locations, so that the effect of the first aspect of the invention can be improved.

  In the orthokeratology contact lens of the invention according to claim 3, since the introduction hole or the introduction groove is provided at the opposing position, the effect of the invention according to claim 1 or claim 2 can be effectively exhibited. Can do.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments that are considered to be the best of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is an explanatory view of an orthokeratology contact lens (hereinafter also simply referred to as a contact lens) 10, the right side is a sectional view of the contact lens 10, and the left side is a back side (inner surface side, corneal side) of the contact lens 10. The figure seen from) is shown. As shown in the cross-sectional view of FIG. 1, the orthokeratology contact lens 10 is formed such that the arc of the back surface of the central portion 11 has a larger curvature than the arc of the back surface of the outer peripheral portion 12, that is, approaches a flat shape. The cornea can be pressed and attached. The orthokeratology contact lens 10 is formed of a material having high oxygen permeability by a polymer such as methyl methacrylate (MMA), a silicon-containing compound, or a fluorine-containing compound.

  The back surface of the central portion 11 of the orthokeratology contact lens 10 is larger (flat) than the patient's corneal curvature, and is formed with a corneal recess 13 called a base curve 13a. The thickness of the central part 11 is adjusted by factors such as the required power when the contact lens 10 is worn and the hardness of the patient's cornea. The back surface of the outer peripheral portion 12 is called an alignment curve 12a or the like, but has a smaller curvature (tighter) than the base curve 13a so as to match the patient's cornea. At the boundary between the base curve 13a and the alignment curve 12a, a reverse curve 14 having a smaller curvature than the base curve 13a and the alignment curve 12a is provided, so that the strength of myopia to be corrected, the shape of the patient's cornea, etc. Adjusted. Regarding the thickness of the contact lens 10, the base curve 13a is usually the thinnest and the alignment curve 12a is the thickest. Introducing holes 15 penetrating from the front surface to the back surface of the contact lens 10 are provided at four positions at 90 ° intervals in the circumferential direction at an intermediate position in the radial direction of the outer peripheral portion 12. The introduction hole 15 is formed in a direction (radial direction) substantially perpendicular to the surface of the contact lens 10. These introduction holes 15 function to guide tear fluid from the front surface to the back surface of the contact lens 10.

  Instead of the introduction hole 15, the following introduction groove may be provided. That is, as shown in FIG. 2, an introduction groove 16 that communicates from the outer peripheral edge to the caulking concave portion 13 is formed at a position facing the back surface of the outer peripheral portion 12 of the contact lens 10 by 180 degrees. The introduction groove 16 is formed with a substantially constant depth from the outer peripheral edge 17 of the contact lens 10 to the caulking recess 13. In the wearing state of the contact lens 10, the introduction groove 16 functions to guide tear fluid from the outer peripheral edge 17 of the contact lens 10 to the caulking recess 13. Usually, the introduction hole 15 is effective when the eyeball is nearly spherical, and the introduction groove 16 is effective in the case of astigmatism.

  Here, the curved surface configuration of the orthokeratology contact lens 10 will be further described. The curved surface of the back surface of the central portion 11 is called a base curve 13a, a central zone or an optical zone. By flattening this portion, refractive errors are temporarily reduced by wearing the contact lens 10, and myopia is restored. It is like that. The curved surface on the back surface of the outer peripheral portion 12 is called an alignment curve 12a, and is designed only in parallel with the cornea, and is fitted here to be centered. The reverse curve 14 on the rear surface of the boundary portion is called a fitting curve, and is a curve connecting the base curve 13a and the alignment curve 12a. The curved surface on the back surface of the outer peripheral edge 17 is referred to as a peripheral curve 17a, which facilitates tear fluid exchange and prevents the contact lens 10 from adhering to the eyeball in the same manner as a normal hard contact lens. The curvatures of the base curve 13a, the alignment curve 12a, etc. vary depending on the degree of myopia, the shape of the eyeball, etc., that is, depending on the person. Therefore, the shape of the orthokeratology contact lens 10 is a combination of curves peculiar to each patient.

Next, a method of using the orthokeratology contact lens 10 will be described.
As shown in FIG. 3 (a), the caulking concave portion 13 of the orthokeratology contact lens 10 is configured to press the central portion of the surface of the cornea 18 of the eyeball. At this time, in the case of the naked eye, as shown by a two-dot chain line in FIG. 3A, light entering the eye is refracted by the cornea 18 and the crystalline lens 19, and the focal point is located in front of the retina 20, which is myopia. . In this state, the object will appear blurred.

  As shown in FIG. 3 (b), the orthokeratology contact lens 10 is attached to the eyes in the same manner as a normal hard contact lens before going to bed, and the state is kept during going to bed. At that time, fitting is performed at the outer peripheral portion 12 having the alignment curve 12 a of the contact lens 10, centering is performed, and the contact lens 10 is maintained at a predetermined position of the cornea 18. In this state, the central portion 11 having the base curve 13a of the contact lens 10 is pressed so as to change the curve of the surface of the cornea 18 (corneal epithelium). This pressing is continued for, for example, 8 hours while sleeping, and the shape of the cornea 18 is corrected so as to approach flatness while sleeping. Since the cornea 18 is a soft tissue that is actively metabolized, its shape is easily changed. Once the shape is changed, it is “quesed”, and it takes a certain amount of time to return. Accordingly, the orthokeratology contact lens 10 is worn every night at bedtime, so that the crushed shape can be kept longer.

  At this time, as shown by a two-dot chain line in FIG. 3B, the light passes through the contact lens 10, the refraction is suppressed by the cornea 18, the light is refracted by the crystalline lens 19, and the focal point is on the retina 20. To position. Accordingly, the state of myopia is improved, the visual acuity is restored, and the object can be clearly recognized.

  As shown in FIG. 3C, even if the orthokeratology contact lens 10 is removed when waking up in the morning, the cornea 18 is attached by the contact lens 10 to form the attachment portion 18 a. Therefore, as shown by a two-dot chain line in FIG. 3C, the light passes through the crease 18a of the cornea 18, where refraction is suppressed, and the light is refracted by the crystalline lens 19, and its focal point is located on the retina 20. . Therefore, the visual acuity is maintained, and it is possible to spend the day with the naked eye with the orthokeratology contact lens 10 removed.

  Now, the operation of this embodiment will be described. In the orthokeratology contact lens 10, four introduction holes 15 penetrating from the front surface to the back surface are provided in the outer peripheral portion 12 at intervals of 90 degrees in the circumferential direction. For this reason, when the orthokeratology contact lens 10 is mounted, tears are guided from the surface of the outer peripheral portion 12 of the contact lens 10 to the back surface through the introduction hole 15. At this time, lacrimal fluid flows from the introduction hole 15 toward the caulking concave portion 13 on the back surface of the contact lens 10 and also flows from the introduction hole 15 in the circumferential direction as indicated by an arrow in FIG.

  Alternatively, the orthokeratology contact lens 10 is provided with an introduction groove 16 that communicates from the outer peripheral edge 17 to the caulking recess 13 at a position facing the back surface of the outer periphery 12 by 180 degrees. For this reason, the tears flow from the introduction groove 16 toward the caulking recess 13 and also flow from the introduction groove 16 in the circumferential direction as indicated by arrows in FIG. Therefore, in either case of the introduction hole 15 or the introduction groove 16, tears can be replenished to the back surface of the outer peripheral portion 12 of the contact lens 10 fitted to the cornea 18.

The effects exhibited by the embodiment described in detail above are collectively described below.
In the orthokeratology contact lens 10 according to the embodiment, the outer peripheral portion 12 is provided with the introduction hole 15 penetrating from the front surface to the back surface or the introduction groove 16 communicating with the caulking concave portion 13 from the outer peripheral edge 17 on the back surface. Therefore, when the orthokeratology contact lens 10 is attached to the eye, tears are replenished between the back surface and the cornea 18 surface via the introduction hole 15 or the introduction groove 16, and adhesion to the cornea 18 is suppressed and stable. Can be obtained. In particular, even a person with symptoms such as dry eye can easily exchange tears and can have a good effect on correcting myopia.

  Since the introduction holes 15 are provided at four locations and at equal intervals in the circumferential direction, and the introduction grooves 16 are provided at two locations, the amount of tears supplied can be increased. The effect can be improved.

  -Since two pairs of the introduction holes 15 are provided at positions opposed to each other by 180 degrees and one pair of introduction grooves 16 are provided at positions opposed to each other by 180 degrees, tears can be easily guided to the entire circumference. The effect of can be exhibited effectively.

It should be noted that the embodiment described above can be modified and embodied as follows.
As shown in FIG. 4A, the shape of the introduction hole 15 may be tapered so that the opening diameter on the front surface side of the orthokeratology contact lens 10 is large and the opening diameter on the back surface side is small. it can. In this case, the lacrimal fluid is easily introduced into the introduction hole 15.

-As shown in FIG.4 (b), the shape of the introduction hole 15 can also be formed in the ellipse shape extended in the circumferential direction.
As shown in FIG. 5A, the shape of the introduction groove 16 is formed with a recess 21 that is recessed in a hemispherical shape in the middle thereof, and tear fluid is accumulated in the middle portion of the introduction groove 16 in the circumferential direction. It can also be configured to facilitate the guidance.

  As shown in FIG. 5B, the shape of the introduction groove 16 is tapered so that the outer peripheral edge 17 side is wide and the caulking concave portion 13 side is narrow so as to facilitate the introduction of tears. It can also be configured.

It is also possible to change the number of introduction holes 15 to 2 places, 3 places, etc., and the number of introduction grooves 16 to 3 places, 4 places, etc.
Next, the technical idea that can be grasped from the embodiment will be described below.

  The orthokeratology contact lens according to any one of claims 1 to 3, wherein the introduction hole is formed in a direction perpendicular to the surface. When constituted in this way, in addition to the effect of the invention according to any one of claims 1 to 3, tear fluid can be guided at a short distance from the front surface to the back surface of the orthokeratology contact lens.

  The orthokeratology contact lens according to any one of claims 1 to 3, wherein the introduction groove is formed at a certain depth. When constituted in this way, in addition to the effect of the invention according to any one of claims 1 to 3, tear fluid can be smoothly guided from the outer peripheral edge of the orthokeratology contact lens to the caulking recess.

The schematic explanatory drawing which shows the contact lens for orthokeratology which has the introduction hole in embodiment. The schematic explanatory drawing which shows the contact lens for orthokeratology which has the introduction groove | channel in embodiment. (A)-(c) is a schematic explanatory drawing which shows the effect | action of the contact lens for orthokeratology. (A) is a partial expanded sectional view which shows another example of the introduction hole of the contact lens for orthokeratology, (b) is a partial enlarged front view which shows another example of the introduction hole. (A) is a partial expanded sectional view which shows another example of the introduction groove | channel of the contact lens for orthokeratology, (b) is a partial enlarged front view which shows another example of an introduction hole.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Orthokeratology contact lens, 11 ... Center part, 12 ... Outer peripheral part, 13 ... Indentation concave part, 15 ... Introduction hole, 16 ... Introduction groove, 18 ... Cornea.

Claims (3)

Orthokeratology contact lens that is attached to the eyes at bedtime to change the shape of the cornea to correct myopia and to be removed with the naked eye removed at non-sleeping time.
A recess for forming a dent is formed on the back surface of the central portion, and an introduction hole penetrating from the front surface to the back surface is provided on the outer peripheral portion thereof or an introduction groove communicating with the dent for recession from the outer peripheral edge is provided on the back surface. An orthokeratology contact lens, characterized in that it is guided to the back surface of the outer peripheral portion through an introduction hole or an introduction groove. The orthokeratology contact lens according to claim 1, wherein the introduction hole or the introduction groove is provided at a plurality of locations. The orthokeratology contact lens according to claim 1, wherein the introduction hole or the introduction groove is provided at a facing position.

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