JP3587456B2 - Corneal correction lens - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a corneal correction lens. Specifically, by providing a tear outflow prevention part at the inner end of the alignment curved surface of the corneal correction lens, the tear filled between the cornea and the corneal correction lens during sleep, when worn on the eyeball, particularly during sleep. By preventing inadvertent outflow from the corneal correcting lens, the correcting effect on the cornea is enhanced, and the inflammation of the cornea can be prevented.
[0002]
[Prior art]
In order to correct myopia and the like, the surface curvature of the cornea may be restored to the original value. Explaining from the structure of the human eye, the human eye 10 is as shown in FIG. 6, in which the subject light enters from the cornea 12, is refracted by the crystalline lens 14 serving as a lens, and enters the vitreous body 16, By stimulating the visual cells of the retina (not shown) on the back side of the vitreous body 16, the user senses that the brain is the subject.
[0003]
When the subject light is normally imaged on the retina, the subject image can be viewed normally. On the other hand, if the subject light forms an image in front of the retina, the image looks blurred. In this case, the correction position is corrected by a corrective lens (glasses or contact lenses) so that the image formation position is on the retina. Thus, the subject image can be correctly viewed without blurring.
[0004]
Assuming that the solid line shown in FIG. 7 indicates the cross-sectional shape of the cornea 12 having a normal curvature, the surface curvature of the cornea 12 is distorted in the state of myopia, and has a convex front surface curvature (shown by a broken line). If the surface curvature of the cornea 12 is corrected as shown by the solid line, the visual acuity will return to a normal value even without the corrective lens.
[0005]
From such a viewpoint, a lens used to correct the surface curvature of the cornea 12 is a cornea correction lens. FIG. 8 shows an example of the corneal correction lens 20. The corneal correction lens 20 is a lens having an inner curved surface 20a having a curvature close to the surface curvature of the normal cornea 12 (see a solid line in FIG. 7).
[0006]
The curvature of the surface 12a of the deformed cornea 12 is corrected using the cornea correction lens 20. For example, the corneal correction lens 20 is attached to the cornea 12 while sleeping, and the cornea 12 is corrected. The pressure on the corneal correction lens 20 by the eyelid is transmitted to the cornea 12 via the corneal correction lens 20, so that the surface 12 a of the cornea 12 fits with the inner surface 20 a of the corneal correction lens 20.
[0007]
During sleep, the state in which the eyelids are closed continues for a long time, so that the corneal surface 12a is assimilated to the inner surface 20a of the corneal correction lens 20, and the assimilated inner surface state even when the corneal correction lens 20 is removed. You will keep it for a while. Therefore, by continuing to attach the corneal correction lens for this correction, the assimilation time of the inner surface 20a gradually increases, and the subject image can be clearly recognized without using a daytime correction lens.
[0008]
However, it was found that the cornea correction lens 20 having the shape as shown in FIG. this is,
First, since the action on the cornea 12 is merely a compression through the corneal correction lens 20, the surface 12a of the cornea 12 cannot be assimilated to the shape of the inner surface 20a of the corneal correction lens 20.
[0009]
Second, since the surface 12a of the cornea 12 is attracted to the inner surface 20a of the corneal correction lens 20 and the force for adhering it is not sufficiently applied, the surface 12a of the cornea 12 is assimilated to the inner surface 20a of the corneal correction lens 20. Not that.
I think that the.
[0010]
If the inner surface of the corneal correction lens 20 becomes negative pressure by mounting the lens, the surface 12a of the cornea 12 can be suctioned and adhered to the inner surface 20a of the corneal correction lens 20, and the corneal surface 12a can be corrected by the suction action. It can be assimilated to the inner surface 20a of the lens 20.
[0011]
However, in the structure shown in FIG. 8, it is difficult to maintain the inside of a small annular cavity formed between the corneal surface 12a and the corneal surface 12a by mounting the lens under negative pressure. This is because the force for attracting the corneal surface 12a to the lens inner surface 20a becomes weak.
[0012]
In order to solve such a problem, a corneal correction lens 20 having an inner surface as shown in FIG. 9 has been proposed. The corneal correction lens 20 has a different curvature of the inner surface between a region close to the eye axis with the eye axis interposed and a region other than the eye axis. In other words, the inner surface 20a of the corneal correction lens 20 is constituted by two inner surface curvatures, which are the inner surface curvature Rb having a smaller curvature than the inner surface curvature Ra with respect to the inner surface curvature Ra of a portion near the eye axis. I have.
[0013]
Further, the outer peripheral portion (alignment curved surface) 20 b of the corneal correction lens 20 is designed to be located slightly inside the cornea 12. The transition from the inner surface curvature Ra to Rb is referred to as a transition point p for convenience of explanation.
[0014]
The first inner surface curvature Ra is larger than the surface 12a curvature of the cornea 12 near the eye axis (the curved surface is indicated by a broken line). Therefore, as shown in FIG. 9, the relationship between the cornea 12 and the corneal correction lens 20 before wearing is such that the corneal surface 12a protrudes near the eye axis, and the lens side protrudes on the outer peripheral end surface side.
[0015]
Therefore, when the corneal correction lens 20 is actually mounted on the cornea 12, the surface shape of the cornea 12 near the eye axis is distorted by the inner surface 20a of the corneal correction lens 20, as shown in FIG. As a result, a slight cavity 22 is formed between the inner surface 20a of the corneal correction lens 20 per transition point p and the surface 12a of the cornea 12 itself. In addition, since the alignment portion 20b is located slightly inside the cornea 12, when the corneal correction lens 20 is attached, the alignment portion 20b lightly presses the surface 12a of the cornea 12, so that the cavity Reference numeral 22 indicates a state in which it is closed from the outside.
[0016]
Thereby, when the lens is pressed against the cornea 12, the inside of the cavity 22 becomes negative pressure, the surface 12a of the cornea 12 is lightly sucked and sucked on the inner surface 20a of the cornea correcting lens 20, and the pressure when the eyelid is closed. Thus, the suction / suction state is maintained.
[0017]
When the corneal corrective lens 20 is actually mounted, if artificial tears or the like are applied to the inner surface 20a of the corneal corrective lens 20, the artificial tears and tears from the lacrimal glands are slightly contained in the cavity 22. Will be stored.
[0018]
The light suction of the surface 12a of the cornea 12 onto the inner surface 20a of the cornea correcting lens 20 means that the cornea 12 is pressed through the cornea correcting lens 20 according to the opening and closing of the eyelid 26 as shown in FIGS. Therefore, the surface 12a of the cornea 12 is easily assimilated to the inner surface 20a of the corneal correction lens 20. While the corneal correction lens 20 is being worn, the above-described negative pressure acts to suck and press the cornea 12. The surface 12a approaches the shape of the inner surface 20a of the corneal correction lens 20. It is said that the reduction of the catabolic effect of the surface 12a of the cornea 12 to return to its original state results in a longer holding time of the curved surface, and the curved surface recovers until the naked eye is not inconvenienced.
[0019]
[Problems to be solved by the invention]
However, even with the corneal correction lens 20 as shown in FIG. 9, a sufficient effect has not yet been obtained. It is for the following reasons.
[0020]
The curvature of the alignment section 20b of the corneal correction lens 20 is designed to match the curvature of the corneal surface 12a. As a result, the application and release of pressure to the corneal correction lens 20 are repeated according to the opening and closing of the eyelid. Along with this, although slightly, the cornea 12 is pressed toward the crystalline lens 14 via the cornea correction lens 20, and the cavity 22 is also pressed at that time, and the pressure is accumulated in the cavity 22. The tear gradually flows out of the corneal correction lens 20, and as a result, the negative pressure gradually weakens, and the effect of sucking the corneal surface 12a is weakened.
[0021]
When the suction to the cornea 12 is weak, the assimilation of the corneal surface 12a is weakened, so that the expected assimilation cannot be obtained. This may lead to insufficient correction of the cornea 12. In addition, when the tear in the cavity 22 is insufficient, the cornea 12 tends to be inflamed.
[0022]
In view of the above, the present invention has solved such a conventional problem, and proposes a corneal correction lens that can enhance the corneal correcting effect by preventing the tear fluid from flowing out of the cavity.
[0023]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the corneal correction lens according to the present invention described in claim 1, a first lens curved surface having a first curvature centered on the eye axis;
A second lens curved surface having a second curvature so as to be continuous with the first lens curved surface;
An alignment curved surface connected to the second lens curved surface,
The first curvature is selected to be larger than the surface curvature of the cornea near the eye axis, and the second curvature is selected to be smaller than the surface curvature.
A tear outflow prevention portion is provided at a transition portion that transitions from the second lens curved surface to the alignment curved surface.
[0024]
In the present invention, a tear outflow prevention section is provided at a transition section that transitions from the second lens curved surface to the alignment curved surface. The tear outflow prevention portion is a projection slightly projecting toward the cornea.
[0025]
When the corneal correction lens is attached to the cornea, the cornea is pressed by the corneal correction lens. Due to this compression, a cavity is formed between the first and second lens curved surfaces having different curvatures, and the inside of the cavity is in a negative pressure state. Since the surface of the cornea is attracted to the inner surface of the corneal correction lens when the negative pressure state is reached, the corneal surface has a curved surface substantially the same as the inner surface of the corneal correction lens.
[0026]
Since there is a tear outflow preventing portion between the second lens curved surface and the alignment curved surface, the tear outflow preventing portion relatively slightly presses the cornea by the tear outflow preventing portion as compared with the related art. As a result, even if the pressure applied to the corneal correction lens increases or decreases due to opening and closing of the eyelid, it is possible to prevent the tear fluid from flowing out, and thereby the negative pressure state in the cavity is favorably maintained.
[0027]
As a result, while the corneal correction lens is worn, the surface of the cornea is suctioned and adsorbed to the inner surface of the corneal correction lens, so that the corneal assimilation is performed while the corneal correction lens is mounted. The action is promoted. If the corneal correction lens is removed, the corneal assimilation gradually weakens.However, by repeating this lens mounting, for example, at bedtime, the surface of the cornea can gradually maintain the same state as the inner surface of the corneal correction lens for a long time. become able to. Eventually, the naked eye will be able to restore sufficient vision.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of a corneal correction lens according to the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an embodiment of a corneal correction lens 28 according to the present invention. The curvature of the lens inner surface 30 of the corneal correction lens 28 is selected so as to be substantially the same as the surface curvature of the cornea 12 when normal visual acuity is obtained with the naked eye.
[0029]
For this reason, the corneal correction lens 28 includes a ring-shaped first lens curved surface (base curved surface) 30a having a first curvature Ra centered on the eye axis, and a ring formed so as to be continuous with the first lens curved surface 30a. A second lens curved surface (fitting curved surface) 30b having a second curvature Rb formed in the shape of a circle, and an alignment curved surface 30c forming the outermost peripheral end surface continuous with the second lens curved surface 30b.
[0030]
The first curvature Ra is selected to be larger than the surface curvature of the cornea 12 near the eye axis, while the second curvature Rb is selected to be smaller than the surface curvature of the cornea 12. Therefore, if the surface 12a of the normal cornea 12 is indicated by a broken line in FIG. 1, the relationship between this surface 12a and the inner surface 30 of the cornea correcting lens 28 is as shown in FIG. That is, as shown in FIG. 1, the relationship between the cornea 12 and the corneal correction lens 20 before wearing is such that the corneal surface 12a protrudes on the first lens curved surface 30a near the eye axis and the lens outer periphery on the second lens curved surface 30b. On the other hand, the end face side is in a state where the lens side protrudes.
[0031]
The curvature Rc of the alignment curved surface 30c is selected to be substantially the same as the outer curvature of the cornea 12. Therefore, the alignment curved surface 30c is substantially the same as the surface 12a of the cornea 12.
[0032]
According to the present invention, the tear fluid outflow prevention part 32 is provided at a transition part that transitions from the second lens curved surface 30b to the alignment curved surface 30c. The tear outflow preventing portion 32 is a ring-shaped protrusion (ring protrusion) that projects slightly inward from the surface 12a of the cornea 12. Therefore, as shown in FIG. 2 in an enlarged manner, a part thereof protrudes slightly toward the cornea 12 from the intersection of the extension of the second lens curved surface 30b and the extension of the alignment curved surface 30c.
[0033]
In order to reduce the influence on the cornea 12 when worn, in this embodiment, the cross section of the tear outflow prevention portion 32 has a conical shape with a rounded head.
[0034]
A depressurizing concave portion 36 is provided between the tear outflow preventing portion 32 and the alignment curved surface 30c. Since the pressing force of the tear outflow preventing portion 32 on the corneal surface 12a is slightly increased by the depressurizing concave portion 36, the effect of the tear outflow preventing portion 32 is enhanced, and the tear is moved toward the alignment curved surface 30c. From the outside to the outside can be more effectively prevented. Here, the tear outflow prevention portion 32 has a width of about 0.1 mm, and the width of the depressurized concave portion 36 is about 1.0 mm.
As the corneal correction lens 28, a so-called hard lens that slightly transmits oxygen is used.
[0035]
Now, when the corneal correction lens 28 thus configured is mounted on the cornea 12, the relationship becomes as shown in FIG. Since the first lens curved surface 30a is larger than the curvature of the cornea 12 near the eye axis, the surface 12a of the cornea 12 is compressed by the inner surface 30a when the lens is worn, and becomes slightly flat. Since the lens has a curvature different from that of the lens curved surface 30b, a slight cavity (gap), that is, an annular cavity 22 is formed between the lens 12 and the surface 12a of the cornea 12 near the transition point p by mounting the lens. The artificial tears applied to the inner surface 30 of the correction lens 28 accumulate in the cavity 22.
[0036]
Further, the pressure on the cornea 12 when the lens is attached causes negative pressure inside the cavity 22. When the corneal correcting lens 28 is attached to the corneal surface 12a, the tear outflow prevention unit 32 lightly presses the corneal surface 12a. 36, the negative pressure state in the cavity 22 is favorably maintained.
[0037]
FIG. 4 shows a state in which the corneal correction lens 28 is mounted on the cornea 12. At this time, the eye lid 26 is in an open state, and FIG. 5 is in a closed state. When the eyelid 26 is closed, the corneal correction lens 28 is pushed by the eyelid 26, and thus the pressure between the corneal correction lens 28 and the cornea 12 becomes negative, and the surface 12a of the cornea 12 becomes inside the corneal correction lens 28. It is sucked and drawn to the surface 30 side. Pressing and releasing of the cornea 12 are repeated by blinking of the eye lid 26, but also in this case, the tear in the cavity 26 flows out through the alignment curved surface 30c by the action of the tear outflow preventing portion 36. Is greatly suppressed, and the initial negative pressure state can be maintained.
[0038]
Since the suction / adsorption to the corneal surface 12a is maintained while the negative pressure state is maintained between the corneal correction lens 28 and the cornea 12, for example, the corneal correction lens 28 may be worn while sleeping. For example, during this time, the corneal surface 12a is constantly drawn to the inner surface 30 of the corneal correcting lens 28, and the corneal surface 12a is assimilated to the inner surface 30 of the corneal correcting lens 28.
[0039]
If the corneal correcting lens 28 is removed, the correcting effect on the corneal surface 12a is lost, so that the assimilation of the cornea 12 is gradually weakened. Thus, even when the corneal correction lens 28 is removed, the corneal surface 12a gradually maintains the assimilated curvature. Despite individual differences, by performing this correction treatment continuously for several days to several weeks, sufficient eyesight can be maintained even with the naked eye during the day.
[0040]
Since the tears accumulate in the above-mentioned cavity 22 without flowing out, not only the negative pressure effect is not diminished, but also the moisture to the cornea 12 is not lost, so that the cornea 12 may be inflamed. Absent.
[0041]
In the above-described embodiment, the depressurizing concave portion 36 is provided so as to be continuous with the tear fluid outflow preventing portion 32, but the depressurizing concave portion 36 can be omitted. Without the depressurizing recess 36, the tear outflow effect is somewhat diminished, but not so much as to affect the correction effect.
The corneal correction lens 28 can be treated not only during bedtime but also during the day. In this case, it is preferable to use a lens with a certain degree of degree for the lens.
[0042]
【The invention's effect】
As described above, according to the present invention, the first lens curved surface having the first curvature around the eye axis, the second lens curved surface having the second curvature so as to be continuous with the first lens curved surface, and the second lens curved surface having the second curvature. The corneal correction lens is constituted by an alignment curved surface that is continuous with the lens curved surface, and a tear outflow prevention portion is provided at a transition portion that transitions from the second lens curved surface to the alignment curved surface.
[0043]
According to this, a negative pressure can be applied between the cornea correcting lens and the cornea by pressing the cornea when the cornea correcting lens is mounted on the cornea, so that the inner surface 30 of the cornea correcting lens has a corneal surface. It is drawn and can correct the surface curvature of the cornea.
[0044]
In addition, since the tear outflow prevention unit is provided at a transition portion that transitions from the second lens curved surface to the alignment curved surface, even if the pressure applied to the corneal correction lens increases or decreases due to opening and closing of the eyelid, the first and second lens surfaces are prevented. It is possible to prevent tear fluid from flowing out of the cavity between the second lens curved surfaces. As a result, the negative pressure state in the cavity can be maintained better than before, and the corneal correcting effect is large.
[0045]
Therefore, by repeatedly wearing the corneal correcting lens, for example, at bedtime, the surface of the cornea can gradually maintain the same state as the inner surface of the corneal correcting lens for a long time, and eventually sufficient visual acuity can be recovered even with the naked eye. The effect can be expected.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of a corneal correction lens according to the present invention.
FIG. 2 is a partially enlarged view of FIG.
FIG. 3 is a diagram showing a relationship with a corneal surface when a corneal correction lens is attached.
FIG. 4 is a diagram showing a state in which the corneal correction lens is mounted and an eye is opened.
FIG. 5 is a view showing a state in which the corneal correction lens is attached and the eye is closed.
FIG. 6 is a diagram showing the structure of an eyeball.
FIG. 7 is a diagram showing the relationship between myopia and the cornea.
FIG. 8 is a diagram showing a state in which a conventional corneal correction lens is mounted.
FIG. 9 is a diagram showing another conventional level structure.
FIG. 10 is a diagram showing a relationship with the cornea at that time.
FIG. 11 is a view showing a state in which the corneal correction lens is mounted and the eyes are opened.
FIG. 12 is a view showing a state in which the corneal correction lens is mounted and the eyes are closed.
[Explanation of symbols]
12 Cornea 12a Surface 20, 28 Corneal Correction Lens 20a, 30 Inner Surface 30a First Lens Curved Surface 30b Second Lens Curved Surface 30c Alignment Curved Surface 32 Tearing Outflow Prevention Unit 36 Depressurized Recessed Part 26 Eyelid

Claims (3)

A first lens curved surface having a first curvature centered on the eye axis;
A second lens curved surface having a second curvature so as to be continuous with the first lens curved surface;
An alignment curved surface that is continuous with the second lens curved surface,
The first curvature is selected to be larger than the surface curvature of the cornea near the eye axis, and the second curvature is selected to be smaller than the surface curvature.
A corneal correction lens, wherein a tear outflow prevention portion is provided at a transition portion that transitions from the second lens curved surface to the alignment curved surface. 2. The corneal correction lens according to claim 1, wherein the tear outflow prevention section is a slight protrusion. 3. The corneal correction lens according to claim 2, wherein a depressurizing recess is formed during a transition from the protrusion to the alignment curved surface.

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