JPH11174388A - Toric contact lenses - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good toric contact lens which has excellent axial stability on a cornea, has no adverse effect of a prism component in an optical region, and does not cause an unpleasant foreign-body sensation even when worn. I do. SOLUTION: This is an inner toric contact lens having an optical region 1 in a central portion and a non-optical region 2 outside an outer periphery 12 thereof, and has a partial bulge 3 as an astigmatic axis stabilizing structure only in the non-optical region 2. And the entire circumference of the lens outer edge is formed with a constant thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toric contact lens for correcting astigmatism, and more particularly, to preventing rotation on a cornea during wearing, and a rotation preventing structure having an adverse effect on optical performance and wearing feeling. Not about toric contact lenses.

[0002]

2. Description of the Related Art Generally, astigmatism is a state in which light emitted from one point in the external world does not converge to one point in the eye because the cornea and lens are not spherical. Toric contact is used as a contact lens for correcting astigmatism. Lenses are conventionally known. A toric contact lens is a contact lens in which the lens outer surface (front surface) or the lens inner surface (rear surface) has different radii of curvature in two orthogonal meridian directions. The meridian indicating the maximum value or the minimum value of the radius of curvature is called an astigmatic axis. However, when the lens rotates during wearing, there is a disadvantage that the astigmatic axis is shifted and visual acuity is likely to be unstable.

[0003] Toric contact lens rotation prevention,
Generally, the following five methods are used to stabilize the shaft.

(1) Prism ballast method: A method in which the lower part of the lens is made relatively heavy by forming a prism and a lens in a combined shape, which is advantageous in preventing rotation.
It has drawbacks in optical performance and wearing feeling.

(2) Truncation method: A method in which a notch is provided in a part of the outer periphery of a lens, which can be expected to have an optical performance, but has a disadvantage that the effect of preventing rotation is not sufficient.

(3) Slab-off method: often used in combination with the prism ballast method, which aims to improve the wearing feeling by thinning a part of the lens outer periphery, but has a sufficient rotation preventing effect. Not have the disadvantages.

(4) Inner surface toric method: A method in which the inner surface of a lens is formed in a toric curve in a shape conforming to the corneal curvature, which has an excellent wearing feeling, but has a drawback that the effect of preventing rotation is not sufficient.

(5) Dynamic stabilization method: A method in which the upper and lower portions of the lens are thinned and the lens is sandwiched between the upper and lower eyelids, although an anti-rotation effect can be expected, but there is a problem in wearing feeling.

Each of the above methods has advantages and disadvantages. Therefore, various inventions have been made in an attempt to eliminate the conventional disadvantages. The toric contact lens described in Japanese Patent Application Laid-Open No. Hei 4-212925 proposes a modification of the slab-off method of the above (3), and is expected to have an effect of reducing irritation to upper and lower eyelids. Since the difference in weight between the upper part and the lower part is not sufficient, the effect of preventing rotation on the cornea is insufficient, and a good and stable effect may not be obtained.

The toric contact lens described in Japanese Patent Application Laid-Open No. Hei 6-34920 is characterized in that
And a slab-off method of (3) are proposed, which can be expected to prevent lens rotation and reduce irritation to the eyelids. That is, it is recognized as being shifted in the vertical direction. Therefore, when the lenses are worn on both eyes, unless the amounts of the right and left prisms are made equal, a left-right difference is added together with the image jump, so that good and stable visual acuity may not be obtained.

Further, the toric contact lens described in Japanese Patent Application Laid-Open No. 61-83518 is a lens constructed based on a different concept from the above (1) to (5). That is, by forming a bulge in the shape of a droplet at one place at the lens peripheral end, an anti-rotation effect,
It is aimed at improving the feeling of wearing. However, due to the structure of the bulge, the height of the bulge peaks near the lens peripheral end, and the height of the bulge decreases rapidly toward the peripheral end. The substance may cause adverse effects on the lower eyelid, causing discomfort and foreign body sensation.

[0012]

As described above, the contact lenses described in the prior art also have advantages but also disadvantages.

An object of the present invention is to solve these problems, that is, it has excellent axial stability on the cornea, has no adverse effect of the prism component in the optical region, and has an unpleasant foreign-body sensation even in wearing sensation. An object of the present invention is to provide a good toric contact lens which does not cause a problem.

[0014]

The toric contact lens according to the present invention is an inner toric contact lens having an optical region in the center and a non-optical region on the outer periphery thereof, and astigmatism only in the non-optical region. It is characterized in that it has an axis stabilizing structure and that the entire outer periphery of the lens is formed with a constant thickness.

The toric contact lens according to a second aspect of the invention is characterized in that the astigmatic axis stabilizing structure is a partial bulge provided on the outer surface of the non-optical area.

According to a third aspect of the present invention, in the toric contact lens, the height of the partial bulge is set so as to gradually increase from the outer periphery of the bulge toward the center of the bulge. Features.

The toric contact lens according to the invention of claims 4, 5 and 6 is characterized in that in claim 3, the partial bulge has a crescent shape, a fan shape and an elliptical shape when viewed from the front of the lens. And

A toric contact lens according to a seventh aspect of the present invention is characterized in that, in any one of the third to sixth aspects, the partial bulge is formed in a plurality.

The toric contact lens according to any one of claims 8 and 9 is characterized in that, in any one of claims 3 to 7, the outer surface of the optical region of the lens is a toric surface and an aspheric surface, respectively.

According to the present invention, as described above, the optical region of the lens has a prismatic structure, that is, a so-called general toric contact lens, but has a continuous curved surface in the non-optical region. It has a configuration with partial bulge while maintaining smoothness. This partial bulge exerts a ballast effect and stabilizes the axis of astigmatism, but has no optical effect on the optical region since it is present in the non-optical region. Furthermore, the height of this partial bulge gradually decreases as it approaches the vicinity of the lens outer peripheral end, and in the vicinity of the lens outer peripheral end, the entire circumference of the lens has a shape similar to that of a general contact lens. In this way, by adjusting the vicinity of the outer peripheral end of the lens, which is said to have the greatest effect on the feeling of wearing, an extremely good feeling of wearing can be obtained without causing an unpleasant sensation such as an unpleasant foreign body feeling.

In practicing the present invention, for example, a new machining method called a lathe cutting technique in which a tool rest is slightly moved in a normal direction and / or a rotation axis direction of the material to be cut in synchronization with the rotation of the material to be cut. By using, the practical utility value can be further enhanced. In other words, by using the lathe, the shape of the partial bulge and the fine adjustment of the size can be easily adjusted in response to the change in the lens refractive power and the change in the radius of curvature of the inner surface of the lens. It can be made to order and can be made to order.
Mass production is also possible.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a toric contact lens LA according to the first embodiment. This toric contact lens LA is an inner toric contact lens having an optical region 1 at the center and a non-optical region 2 outside its outer periphery 12, and has an astigmatic axis stable structure only on the outer surface within the non-optical region 2. It has a partial bulge 3A, and has a constant thickness over the entire outer edge near the lens outer peripheral portion 11.

The partial bulge 3A in this case is formed such that its height gradually increases from the outer peripheral portion (corresponding to the curves 13A and 14A) of the bulge 3A toward the center 4 of the bulge 3A. It is formed in a crescent shape when viewed from the front of the lens. Crescent-shaped bulge 3A
13A and the outer curve 14A, the portion surrounded by the inner curve 13A and the outer curve 14A is a curved surface (the surface other than the bulge 3A) that constitutes the outer surface of the other lens non-optical area 2. ). Further, a bulge 3 where the inner circumference curve 13A and the outer circumference curve 14A intersect.
Both ends 15A of A are located on a meridian R2 orthogonal to a meridian R1 passing through the center 4 of the bulge 3A. That is,
The bulge 3A exists in an area that is exactly half of the entire circumference of the lens.

The crescent-shaped bulge 3A has the highest bulge height near the center 4 on the meridian R1, and gradually decreases as it approaches the crescent-shaped inner peripheral curve 13A and outer peripheral curve 14A. The most important part in the configuration is the shape in the vicinity of the outer peripheral curve 14A, and the shape is such that even when the lower eyelid and the lens bulge 3A come into contact with each other at the time of wearing, it does not cause discomfort or foreign matter. That is, when the lens comes into contact with the lower eyelid, the lower eyelid first comes into contact with the lens outer peripheral portion 11 and then comes into contact with the outer peripheral curve 14A and the inner peripheral curve 13A sequentially. Since the curved surface 14A and the inner peripheral curve 13A are smoothly connected through the entire bulging portion 3A of the lens and there is no sudden bulging, the resistance caused by contact with the lower eyelid is minimized, and discomfort and foreign matter Does not create a feeling. In addition, since the partial bulge 3A exerts a ballast effect, the astigmatic axis is stabilized. Moreover, since the bulging portion 3A exists only in the non-optical area 2, the optical area 1
Has no optical effect.

The tip 15 of the crescent-shaped bulge 3A
A has almost no swelling and has the same curvature as the non-optical region 2 other than the swelling 3A portion. For this reason, the position and shape of the tip 15A are not particularly limited.
In the first embodiment of FIG. 1, the position of the distal end portion 15 is set to a position that is about half the width in the meridian direction of the non-optical region 2 and the shape is formed at an acute angle. However, the present invention is not limited to this. Other modified examples when the bulge has a crescent shape are shown below.

In the toric contact lens LB of the second embodiment shown in FIG. 2, an outer peripheral curve 14B of a crescent-shaped bulge 3B is formed parallel to the lens outer peripheral portion 11. And the bulge 3 where the inner circumference curve 13B and the outer circumference curve 14B intersect.
Both end portions 15B of B are disposed at positions near the lens outer peripheral portion 11.

In the toric contact lens LC of the third embodiment shown in FIG. 3, an inner circumference curve 13C of a crescent-shaped bulge 3C is formed parallel to the outer circumference 12 of the optical area 1.
Then, both end portions 15C of the bulge 3C where the inner peripheral curve 13C and the outer peripheral curve 14C intersect are arranged at positions close to the optical region 1.

In the toric contact lens LD of the fourth embodiment shown in FIG. 4, the curvature of the inner curve 13D of the crescent-shaped bulge 3D is set smaller than that of the first embodiment, and the curvature of the outer curve 14D is set to the first. By setting it larger than that of the embodiment, the width of the tip of the bulge 3D is increased. And in this example, the tip 1 of the bulge 3D
5D is forcibly corrected to an obtuse angle.

In the case of the toric contact lens LE of the fifth embodiment shown in FIG. 5, similarly to the fourth embodiment, the curvature of the inner peripheral curve 13E of the crescent-shaped bulge 3E is set smaller than that of the first embodiment. At the same time, by setting the curvature of the outer peripheral curve 14E to be larger than that of the first embodiment,
The width of the tip of the bulge 3E is increased. In this example, the tip 15E of the bulge 3E has a shape that is forcibly rounded. In addition, in the example of FIG. 4 and FIG.
Although an example has been given in which the positions of D and 15E are on the meridian R2, the positions of the tip portions 15D and 15E do not necessarily need to be this position, and may be any positions.

In the toric contact lens LF of the sixth embodiment shown in FIG. 6, the curvature of the inner curve 13F of the crescent-shaped bulge 3F is set to be larger than that of the first embodiment, and the curvature of the outer curve 14F is set to the first. By setting it smaller than that of the embodiment, the width of the tip of the bulge 3F is reduced. Then, the tip 15F of the bulge 3F where the inner peripheral curve 13F and the outer peripheral curve 14F intersect is set at a position shorter than the meridian R2.

In the toric contact lens LG of the seventh embodiment shown in FIG. 7, the curvature of the inner peripheral curve 13G of the crescent-shaped bulge 3G is set smaller than that of the first embodiment, and the curvature of the outer peripheral curve 14G is set to the first. By setting it larger than that of the embodiment, the width of the tip of the bulge 3G is increased. The distal end 15G of the bulge 3G where the inner peripheral curve 13G and the outer peripheral curve 14G intersect is set beyond the meridian R2.

In designing a contact lens, the lens outer diameter, the outer diameter of the optical part, the inner surface radius of curvature, and the like are taken into consideration in consideration of the corneal shape, refractive power, lens material, and the like of the wearer.
Determine the radius of curvature of the outer surface, the center thickness, and the like. Generally, the outer diameter of the soft contact lens is 12 mm to 15 mm, the outer diameter of the optical part is 6 mm to 10 mm, and the inner surface radius of curvature is 6 mm to 10 mm.
mm, the outer surface radius of curvature is 6 mm to 20 mm, and the center thickness is 0.03 mm to 0.50 mm. However, it is sometimes necessary to adjust the crescent shape in consideration of these differences. That is, as shown in FIGS. 2, 3, 6, and 7,
The position where the tip of the crescent-shaped bulge converges is changed, or the shape of the tip is changed as shown in FIGS.

As shown in FIGS. 8, 9 and 10,
Taking into account the position of the center of gravity of the entire lens, the cross-sectional shape (cross-sectional shape in the meridian direction) of the bulge may be an arbitrary shape such as two steps, three steps, or a continuous curved surface.

The toric contact lens LH of the eighth embodiment shown in FIG. 8 and the toric contact lens LI of the ninth embodiment shown in FIG. 9 have crescent-shaped bulges 3H, 3I.
Is composed of two bulges 3H-1 and 3H-2 in the meridian direction. The bulges 3H-1 and 3I-1 on the inner peripheral side are in a range surrounded by the boundary curves 17H and 17I and the inner peripheral curves 13H and 13I. Swelling 3H-2, 3I on outer side
-2 indicates the boundary curves 17H and 17I of the two and the outer peripheral curve 14
H, 14I. 2 bulges 3H
-1, 3H-2, 3I-1, 3I-2 tip 15H,
15I is common. In the example of FIG. 8, the boundary curve 17H is closer to the lens outer peripheral side. That is, the bulge 3 on the inner peripheral side
The width of H-1 is larger than the width of the bulge 3H-2 on the outer peripheral side. Conversely, in the example of FIG. 9, the boundary curve 17I is closer to the inner peripheral side of the lens. That is, the width of the inner bulge 3I-1 is smaller than the width of the outer bulge 3I-2.

In the toric contact lens LJ of the tenth embodiment shown in FIG. 10, the crescent-shaped bulge 3J is constituted by three bulges 3J-1, 3J-2 and 3J-3 in the meridian direction. Two boundary curves 17J-1 and 17J are provided between the inner peripheral curve 13J and the outer peripheral curve 14J of the bulge 3J.
-2 is provided. The inner peripheral bulge 3J-1 is in a range surrounded by the boundary curve 17J-1 and the inner peripheral curve 13J. The middle bulge 3J-2 shows both boundary curves 17J-
1, 17J-2. The bulge 3J-3 on the outer peripheral side is in a range surrounded by the boundary curve 17J-2 and the outer peripheral curve 14J. Three-stage bulge 3J-1, 3J-
The tips 15J of 2, 3J-3 are at a common point.

.. And the outer curves 14A... That define the outer periphery of the crescent shape do not necessarily have to be arc shapes as illustrated, but parabolas and hyperbolas are also conceivable. . Also, the inner circumference curve 13A
The present invention also includes a so-called half-moon or arcuate shape having an infinitely large curvature.

The bulge may be formed in a fan shape.
In the toric contact lens LK of the eleventh embodiment shown in FIG. 11, the bulge 3K has an inner peripheral curve 13K parallel to the outer periphery 12 of the optical region 1, an outer peripheral curve 14K parallel to the lens outer periphery 11, and a fan-shaped end. Is formed in a range surrounded by the end line 15K. In this case, the cross-sectional shape of the bulge 3K along the meridian direction has a trapezoidal shape expanding downward. The two ridge portions 18K of the trapezoid are formed by smooth curves. In addition, there is almost no swelling near the fan-shaped end line 15K, and the curvature is equivalent to the outer surface of the non-optical region 2 other than the swelling portion. For this reason, the above-mentioned bulge has substantially the same effect as a crescent-shaped lens.
Although not illustrated here as another embodiment, FIG.
The relationship of the lenses of FIGS. 4, 5, 6, 7, 8, 9, and 10 to the lens of FIG.

The bulge may be formed in an elliptical shape. In the toric contact lens LM of the twelfth embodiment in FIG. 12, the bulge 3M is formed in an elliptical shape surrounded by a contour 19M. In this case, the elliptical bulge 3
The central portion of M is made higher, and the bulging portion 3M is made lower as it approaches the contour line 19M on the outer peripheral side. The lengths of the major axis and minor axis of the ellipse and the cross-sectional shape of the bulge 3M are appropriately determined based on the lens outer diameter, the optical part outer diameter, the inner surface radius of curvature, the inner surface radius of curvature, the center thickness, and the like. Therefore, it is not particularly limited to the illustrated elliptical shape.

Further, the shape of the bulge as viewed from the front of the lens may be any two of a crescent shape, a sector shape, an elliptical shape, or any other shape.
It may be one shape formed by incorporating a part of one or more shapes as a part of the shape.

In the above embodiment, the case where only one bulge 3A... 3M is provided is shown. In the toric contact lens LN of the thirteenth embodiment in FIG. 13, two elliptical bulges 3N-1 and 3N-2 are provided adjacent to each other. In this case as well, the bulges 3N-1 and 3N-2 have a height at the center thereof, but the height decreases as approaching the outer contour line 19N.
The contour 19N is formed so as to be smoothly continuous with the curvature of the outer surface of the non-optical area 2.

In the toric contact lens LP of the fourteenth embodiment shown in FIG. 14, the inner peripheral curve 13P and the outer peripheral curve 1
A bulge 3P is formed in which the crescent surrounded by 4P is divided into two by a central meridian. In this case, the outline 20P of the boundary between the two bulges 3P-1, 3P-2
, The bulges 3P-1 and 3P-2 start, and the highest position is set near the geometric center of the bulges 3P-1 and 3P-2.

The shape of the bulge is not limited to the examples shown in FIGS. Also, the size and number of the bulges are not limited to the above examples. The outer surface of the optical region 1 of the lens may be a toric surface or an aspheric surface.

[0043]

As described above, according to the present invention,
A toric contact lens that satisfies the three conditions of stabilizing the axial direction of the lens astigmatism at the time of wearing, having no adverse optical effects due to the prism action, and preventing poor wearing due to irritation to the eyelids is obtained at the same time. Further, when the present invention is carried out, it is possible to sufficiently cope with custom-made products manufactured according to the corneal shape and refractive power of the wearer.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a toric contact lens according to a first embodiment of the present invention, where (A) is a side view and (B) is a plan view.

FIGS. 2A and 2B are diagrams showing a configuration of a toric contact lens according to a second embodiment of the present invention, wherein FIG. 2A is a side view and FIG.

3A and 3B are diagrams illustrating a configuration of a toric contact lens according to a third embodiment of the present invention, wherein FIG. 3A is a side view and FIG. 3B is a plan view.

FIGS. 4A and 4B are diagrams showing a configuration of a toric contact lens according to a fourth embodiment of the present invention, wherein FIG. 4A is a side view and FIG.

5A and 5B are diagrams showing a configuration of a toric contact lens according to a fifth embodiment of the present invention, wherein FIG. 5A is a side view and FIG. 5B is a plan view.

FIG. 6 is a side view of a toric contact lens according to a sixth embodiment of the present invention.

FIG. 7 is a side view of a toric contact lens according to a seventh embodiment of the present invention.

FIG. 8 is a side view of a toric contact lens according to an eighth embodiment of the present invention.

FIG. 9 is a side view of a toric contact lens according to a ninth embodiment of the present invention.

FIG. 10 is a side view of a toric contact lens according to a tenth embodiment of the present invention.

11A and 11B are diagrams showing a configuration of a toric contact lens according to an eleventh embodiment of the present invention, wherein FIG. 11A is a side view, and FIG.
Is a plan view.

12A and 12B are diagrams showing a configuration of a toric contact lens according to a twelfth embodiment of the present invention, wherein FIG. 12A is a side view and FIG.
Is a plan view.

13A and 13B are diagrams showing a configuration of a toric contact lens according to a thirteenth embodiment of the present invention, wherein FIG. 13A is a side view, and FIG.
Is a plan view.

14A and 14B are diagrams showing a configuration of a toric contact lens according to a fourteenth embodiment of the present invention, wherein FIG. 14A is a side view, and FIG.
Is a plan view.

[Description of Signs] 1 lens optical area 2 lens non-optical area 3A to 3K, 3M, 3P, 3H-1, 3H-2, 3I-
1,3I-2,3J-1,3J-2,3J-3,3N-
1,3N-2,3P-1.3P-2 Swelling 11 Lens outer periphery 12 Optical region outer periphery

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Akira Shimojo 6-1-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Inside Hoya Healthcare Co., Ltd.

Claims (9)

[Claims] 1. An inner toric contact lens having an optical region at a central portion and a non-optical region on the outer periphery thereof, wherein the toric contact lens has an astigmatic axis stabilizing structure only in the non-optical region, and the entire outer periphery of the lens is constant. A toric contact lens characterized by being formed to a thickness of. 2. The toric contact lens according to claim 1, wherein the astigmatic axis stabilizing structure is a partial bulge provided on an outer surface of a non-optical area. 3. The height of the partial bulge is set so as to gradually increase from the outer peripheral portion of the bulge toward the central portion of the bulge.
The toric contact lens described. 4. The toric contact lens according to claim 3, wherein the partial bulge has a crescent shape when viewed from the front of the lens. 5. The toric contact lens according to claim 3, wherein the partial bulge has a fan shape when viewed from the front of the lens. 6. The toric contact lens according to claim 3, wherein the partial bulge has an elliptical shape when viewed from the front of the lens. 7. The toric contact lens according to claim 3, wherein the partial bulge is divided into a plurality of parts. 8. The toric contact lens according to claim 3, wherein the outer surface of the optical area of the lens is a toric surface. 9. The toric contact lens according to claim 3, wherein an outer surface of an optical area of the lens is an aspherical surface.