JP2018112668A - Orthokeratology contact lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an orthokeratology contact lens that can make surfaces a smooth curved face at the ends of a corrected diameter of the cornea after correction.SOLUTION: An orthokeratology contact lens is for correcting visual acuity by changing the shape of the cornea, and comprises: a central portion referred to as a base area in which a contact lens surface in contact with the cornea is arranged at the center and presses the cornea; an annular portion referred to as a reverse area that is arranged on the periphery of the base area; an annular area referred to as an alignment area that is arranged on the periphery of the reverse area; and an annular portion referred to as a peripheral area that is arranged on the periphery of the alignment area. The width of the base area is within a range of +30%, with a length twice the direct distance from a point at which a curve of the base area and an extended line of a curve of the alignment area are intersected with each other, to a point perpendicularly intersecting with the central axis of the contact lens, as a reference; an annular curved face referred to as a shift area is formed between the base area and reverse area.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a corneal correction contact lens. More specifically, the present invention relates to a corneal correction contact lens having a structure for deforming the shape of the corneal surface.

  As a means to correct myopia, a treatment method (orthokeratology) that changes the focal length of the cornea itself by deforming the shape of the cornea surface by wearing contact lenses with multiple radii of curvature in multiple stages and this treatment A corneal correction contact lens (orthokeratology lens) used in the method is known (for example, Patent Document 1 and Patent Document 2).

  The mechanism of vision correction using a corneal correction contact lens will be described.

  First, in the state of myopia, as shown in FIG. 1, the surface of the cornea 2 has a curvature convex forward with respect to the retina (an aspherical shape convex on the left side in FIG. 1). For this reason, the light is converged in front of the retina 6 without being focused on the retina 6.

  As shown in FIG. 2, the cornea-correcting contact lens 1 is worn on the cornea 2 like a corset to correct the shape of the corneal surface 7 shown in FIG.

  Thereby, even after removing the corneal correction contact lens 1, the corneal surface 7 can be made flat as shown in FIG.

  For this reason, the light passing through the flattened corneal surface is adjusted in refractive power and is focused on the retina 6, so that the visual acuity can be improved for a certain period of time.

  As for a corneal correction contact lens, as shown in FIG. 4, the shape of the surface in contact with the corneal surface is generally divided into at least four parts. That is, a base region that is a concave spherical surface that is placed in the center of the corneal correction contact lens and that presses the corneal surface to correct the surface curve, and is arranged around the base region, and an annular shape that receives the corneal tissue that moves from the base region. Annular alignment area, which is arranged around the reverse area and around the reverse area, and adjusts the fitting between the cornea-correcting contact lens and the cornea and the centering of the cornea-correcting contact lens, forms an edge, removes the lens and cornea-correcting contact for tears An annular peripheral region that helps inflow into the lens.

Japanese Patent No. 3881221 Japanese Patent No. 3585456

  In the conventional corneal correction contact lens 1 as described in Patent Document 1 and Patent Document 2, as shown in FIG. 5, in the base region B and the reverse region R, between the corneal correction contact lens 1 and the corneal surface. A space (tier zone T) is formed and stores tear fluid to prevent inflammation of the cornea, and also functions as an excess part for flowing in the cell tissue of the cornea corrected by pressing the cornea correcting contact lens.

  Here, when the corneal surface corrected by the corneal correction contact lens 1 is observed, the end portion of the corrected portion is a partially corrected corneal surface as shown as an expanding portion 9 of the corneal surface in FIG. It has been found that the radius of curvature is steeper than the radius of curvature of the cornea surface before correction, that is, it swells locally. For this reason, the light incident from the expanding portion 9 on the corneal surface shown in FIG. 6 cannot be focused on the retina 6 shown in FIG. 3, and the visual acuity particularly at night or in a dark place where the pupil diameter 8 expands. It will cause poor correction.

  This is because, as shown in FIG. 5, the space (tier zone T) suddenly expands from the end of the corneal correction diameter, and the transferred corneal cells cannot move sufficiently along the corneal correction contact lens wall surface.

  For this problem, by making the corneal correction diameter wider than the pupil diameter, light from the inflated portion can be prevented from entering, but the cornea is pressed deeply in the direction of the eye axis, which may damage the corneal surface. There was a risk of ruin.

  Therefore, in view of the above problems, the present invention defines the width of the base region B according to the point where the curve of the base region and the extension line of the alignment region intersect, and further, between the base region and the reverse region. By providing the shift region S for guiding the migrating corneal cells along the corneal correction contact lens wall surface, a corneal correction contact lens capable of making the corrected corneal surface a smooth curved surface is provided.

  In order to solve the above problems, the present invention has the following configuration.

  (1) A corneal correction contact lens for correcting visual acuity by changing the shape of the cornea, wherein a contact lens surface in contact with the cornea is arranged in the center and a central portion called a base region that presses the cornea, the base An annular portion disposed around the region and referred to as a reverse region; an annular portion disposed around the reverse region and referred to as an alignment region; and an annular portion disposed around the alignment region and referred to as a peripheral region; And the width of the base region is twice the linear distance from the point where the curve of the base region and the extended line of the alignment region intersect to the point perpendicular to the central axis of the contact lens It is within a range of + 30% based on the length, and is referred to as a shift region between the base region and the reverse region. A orthokeratology contact lens Jo curved is formed.

  (2) The width of the base region is twice as long as the linear distance from the point where the curve of the base region and the extended line of the alignment region intersect to the point perpendicular to the central axis of the contact lens The corneal correction contact lens according to (1).

  (3) The corneal correction according to (1) or (2), wherein the curvature radius of the shift region is formed in a range larger than the curvature radius of the alignment region and smaller than the curvature radius of the base region. It is a contact lens.

  According to the present invention, it is possible to obtain a corneal correction contact lens in which the corneal surface hardly swells locally at the end of the corrected corneal correction diameter.

It is a cornea-shaped eyeball schematic in the state of myopia. It is the eyeball schematic when wearing the corneal correction contact lens. It is the eyeball schematic after removing a corneal correction contact lens. It is the schematic of the conventional corneal correction contact lens. It is a schematic diagram explaining the shape of the conventional corneal correction contact lens. It is a schematic diagram of the cornea surface corrected with the conventional corneal correction contact lens. It is the schematic of the corneal correction contact lens of this invention. It is a schematic diagram explaining the shape of the corneal correction contact lens of this invention. It is a schematic diagram of the corneal surface corrected with the corneal correction contact lens of the present invention.

The present invention is a corneal correction contact lens for correcting visual acuity by changing the shape of the cornea,
The contact lens surface in contact with the cornea
A central part called the base region which is arranged in the center and presses the cornea,
An annular portion disposed around the base region and referred to as a reverse region;
An annular portion disposed around the reverse region and referred to as an alignment region; and an annular portion disposed around the alignment region and referred to as a peripheral region.
The width of the base region is +30 on the basis of a length that is twice the linear distance from the point where the curve of the base region and the extended line of the alignment region intersect to the point perpendicular to the central axis of the contact lens. % And
In addition, the contact lens is a corneal correction contact lens in which an annular curved surface called a shift region is formed between the base region and the reverse region.

  Hereinafter, an example of a preferred embodiment of the present invention will be shown.

  First, the corneal correction contact lens of the present invention is preferably a hard contact lens having high oxygen permeability. As shown in FIG. 7, the corneal correction contact lens of the present invention has a surface shape of 5 in contact with the cornea 2 of FIG. Has one site. They are arranged around the base region B, which is a central spherical portion that is in contact with the cornea 2 shown in FIG. 1 and presses the cornea surface 7 to correct the surface curvature radius. A shift region S for guiding the moving corneal tissue to the reverse region, an annular reverse region R for receiving the guided corneal tissue, and a fitting of the corneal correction contact lens 1 and the cornea 2 and corneal correction arranged around the reverse region R An annular alignment region A that adjusts the centering of the contact lens 1, and a peripheral region P that forms an edge and assists the removal of the lens and the flow of tears into the corneal correction contact lens 1.

The radius of curvature R _B of the base region B, in a cross section containing a contact lens center axis M, the center point C _B is located on the contact lens center axis M, the radius of curvature as the corneal surface 7 is power to be corrected Is determined. Since the shape of the corneal surface 7 changes according to this radius of curvature, myopia can be corrected.

  In the shift region S, the corneal tissue that is moved by correction in the base region B is guided to the reverse region R along the corneal correction contact lens wall surface.

  The reverse region R plays a role of receiving the corneal tissue guided by the shift region S, and a space (tier zone T) is formed between the corneal correction contact lens 1 and the cornea 2 in the shift region S and the reverse region R. . In the tier zone T, the lacrimal fluid is stored between the corneal correction contact lens 1 and the cornea 2 to prevent inflammation of the cornea.

The alignment region A contributes to the centering adjustment of the corneal correction contact lens 1 in contact with the cornea 2 or close to contact with a distance of several microns. In addition, the curvature radius _RA of the alignment region _A is located on the contact lens central axis M so that the fitting radius to the cornea 2 is enhanced, and the corneal surface curvature before correction is determined. it is preferable that a value close to a radius R _K.

  In the peripheral region P, it plays a role in helping the inflow of tears from the end of the corneal correction contact lens 1 to the cornea 2, and the cross-sectional shape forms a rounded conical shape in order to reduce the feeling of foreign objects during wearing. It is preferable.

  Here, as shown in FIG. 7, all the curved surfaces have a radius of curvature centered on the contact lens central axis M, and have a concave saddle shape with respect to the cornea 2 shown in FIG. 1.

  In addition, the transition point J4 between the base region and the shift region where the curved surfaces are connected, the transition point J5 between the shift region and the reverse region, the transition point J2 between the reverse region and the alignment region, and the transition point J3 between the alignment region and the peripheral region are used. In order to prevent the cornea 2 from being scratched, it is preferable that the cornea 2 is rounded, and the radius of curvature is preferably 0.02 to 1.00 mm.

An embodiment of the present invention will be described in detail with reference to FIG. FIG. 8 is a schematic diagram of the corneal correction contact lens 1 of the present invention. In FIG. 8, the width of the base region is W _B , the width of the shift region is W _S , the width of the reverse region is W _R , the width of the alignment region is W _A , the width of the peripheral region is W _P , and the radius of curvature of the base region is R _B , the radius of curvature of the shift region is R _S , the radius of curvature of the reverse region is R _R , the radius of curvature of the alignment region is R _A , and the radius of curvature of the peripheral region is R _P. Further, the K1 point curve and the contact lens center axis of the alignment regions intersect, the linear distance to the K2 point where the extension line and the contact lens center axis M of the curve of the base region intersect the D _P. In addition, a linear distance from a point K3 where the curve of the base region and the extended line of the alignment region intersect to a point K4 perpendicular to the contact lens central axis is defined as _DW .

The curvature radius R _B of the base region is determined so as to be the frequency to be corrected, and the curvature radius R _A of the alignment region is the same as that before correction in order to improve the alignment to the cornea 2. it is preferably a value close to the corneal surface curvature radius R _K.

In the present invention, the width W _B of the base area is twice the linear distance D _W from K3 point where the extension line of the curve of the curve and the alignment region of the base region intersect to K4 point of intersection perpendicular to the contact lens center axis Characterized by having an annular portion that is within a range of + 30% with respect to the length of the region, and that is arranged around the base region and called a shift region that guides corneal tissue moving from the base region to the reverse region To do.

Regarding K3 point where the extension line of the curve of the curve and the alignment region of the base region intersect is the R _B the radius of curvature of the base region, and the radius of curvature of the alignment regions R _A, curve and the contact lens center of the alignment region and K1 that axes intersect derives the straight line distance D _P to K2 point where the extension line and the contact lens center axis M of the curve of the base region intersect.

  Thereby, first, the tier zone T that can be generated between the base region and the corneal surface can be reduced. Further, by guiding the moving cornea from the base region to the reverse region along the corneal correction contact lens wall surface in the shift region S, the corrected corneal curved surface is locally shown in FIG. The resulting corneal surface expansion 9 can be a smooth curve.

Here, the width W _B of the base region, the K3 point of intersection and the extension line of the curve of the curve and the alignment region of the base region is twice the linear distance D _W to K4 point of intersection perpendicular to the contact lens center axis Just by forming the shift region S without making it within the range of + 30% based on the length, the tear zone suddenly expands from the end of the corneal correction diameter, just like the conventional corneal correction contact lens, The corneal surface will swell locally.

Meanwhile, without forming a shift area S, if it is attempted to move the cornea along the orthokeratology contact lenses wall close to the radius of curvature R _R of the reverse area to the radius of curvature R _A of the alignment region, orthokeratology contact lenses As a result, the corneal tissue that moves due to the correction in the base region B cannot be moved, and the expected correction effect cannot be obtained.

Width W _B of the base region of orthokeratology contact lens according to the present invention, the K3 point where the extension line of the curve of the curve and the alignment region of the base region intersect the linear distance D to K4 point of intersection perpendicular to the contact lens center axis _If the length of the cornea is within the range of up to + 30% with reference to a length twice as long as _W , the corneal surface after correction can be made a smooth curved surface by having the above-mentioned shift region S together. Therefore, it is preferable because a practically sufficient effect can be obtained, and it is more preferable if the length is twice the linear distance _DW .

The width _{W S} of the shift area S is preferably 0.05～0.80Mm.

Further, the curvature radius _RS is preferably 0.05 to 9.00 mm. Further, the curvature radius R _S of the shift area S is larger than the radius of curvature R _A of the alignment region, if the radius of curvature R _B smaller than the range of the base region, it is possible to contiguous with respective curved smoothly, Further preferred.

  In addition, about the value and width | variety of a curvature radius of each area | region, it can measure with a contact type contour shape measuring device (made by Mitutoyo Corporation), for example.

  The present invention can be applied as a contact lens for corneal correction.

1: Corneal correction contact lens 2: Cornea 3: Ocular axis 4: Iris 5: Lens 6: Retina 7: Corneal surface 8: Pupil diameter 9: Dilated portion B of corneal surface B: Base region S: Shift region R: Reverse region A : Alignment region P: Peripheral region T: Tier zone J1: Transition point where base region and reverse region intersect J2: Transition point where reverse region and alignment region intersect J3: Transition point where alignment region and peripheral region intersect J4: Base region Transition point where the shift region and the reverse region intersect K1: transition point where the shift region and reverse region intersect K1: a point where the alignment region curve intersects the contact lens central axis K2: a point where the extension line of the base region curve intersects the contact lens central axis K3 : Point where the curve of the base region and the extended line of the alignment region intersect K4: The curve of the base region From the point of intersection and the extension line of the curve of Raimento region, M the point perpendicularly intersects the contact lens center axis: contact lens center axis C _B: center point of the radius of curvature of the base region C _S: the curvature radius of the center point of the shift area C _R : center point of curvature radius of reverse region C _A : center point of curvature radius of alignment region C _P : center point of curvature radius of peripheral region R _K : corneal surface curvature radius before correction R _B : curvature of base region Radius R _S : Curvature radius of shift region R _R : Curvature radius of reverse region R _A : Curvature radius of alignment region R _P : Curvature radius of peripheral region D _P : Point where curve of base region and contact lens central axis intersect Linear distance D _W between the extended line of the alignment region and the point where the central axis of the contact lens intersects: the curve of the base region and the alignment region Linear distance W _B : Base region width W _S : Shift region width W _R : Reverse region width W _A : Alignment region width W _P : Width of peripheral area

Claims (3)

A corneal correction contact lens for correcting vision by changing the shape of the cornea,
The contact lens surface in contact with the cornea
A central part called the base region which is arranged in the center and presses the cornea,
An annular portion disposed around the base region and referred to as a reverse region;
An annular portion disposed around the reverse region and referred to as an alignment region; and an annular portion disposed around the alignment region and referred to as a peripheral region.
The width of the base region is +30 on the basis of a length that is twice the linear distance from the point where the curve of the base region and the extended line of the alignment region intersect to the point perpendicular to the central axis of the contact lens. % And
An corneal correction contact lens, wherein an annular curved surface called a shift region is formed between the base region and the reverse region.   The width of the base region is twice as long as a linear distance from a point where a curve of the base region and an extension line of the alignment region intersect to a point perpendicular to the central axis of the contact lens. Item 10. A corneal correction contact lens according to Item 1.   The corneal correction contact lens according to claim 1 or 2, wherein a curvature radius of the shift region is formed in a range larger than a curvature radius of the alignment region and smaller than a curvature radius of the base region.

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