HK1169715A - Soft contact lens - Google Patents

Description

Soft contact lens

Technical Field

The present invention relates to a soft contact lens worn on a cornea for use. Specifically, a small hole (pinhole) is formed in the center of a light shielding portion for shielding light, whereby any of myopia, hyperopia, astigmatism, and presbyopia can be corrected by the depth of focus generated by the small hole, and night vision around an image can be secured by forming a plurality of fine holes around the small hole.

Background

The subject light incident from the cornea is refracted by the cornea and the crystalline lens to enter the vitreous body, the retina on the back side of the vitreous body is imaged, and the imaged visual information is transmitted to the brain via the optic nerve, so that the subject image visually seen by a person is visually recognized. At this time, when the subject light forms images in front of and behind the retina, the subject light becomes myopia and hyperopia. When the cornea and the crystalline lens are distorted, the focus is not aligned with the retina, and astigmatism occurs.

As a method for correcting such myopia, hyperopia, astigmatism, and the like, correction by glasses, correction by contact lenses, and the like are widely performed. In addition, for correction of presbyopia, bifocal lenses or the like having a distance portion and a near portion in 1 lens are used.

Further, as a technique for reliably correcting presbyopia and the like, a patch which is implanted in the cornea of a patient and includes: a plurality of apertures extending at least partially between an anterior surface and a posterior surface, the anterior surface residing adjacent to the 1 st corneal layer and the posterior surface residing adjacent to the 2 nd corneal layer; an opening portion that transmits substantially all incident light along an optical axis; and a substantially opaque portion surrounding at least a part of the opening (see patent document 1).

Patent document 1: japanese Kokai publication No. 2007-516019

However, the membrane sheet described in patent document 1 is configured to be implanted into the cornea of a patient, and therefore, a surgical operation is required, and there is a problem that it is difficult for a user to use the membrane sheet easily and safely like a general contact lens worn on the cornea. Further, since the plurality of holes of the film are provided for preventing substantial depletion of nutrients in the corneal layer, the film made of an opaque member in a portion other than the opening has the following problems: although some light is incident via the hole for nutrient delivery, sufficient brightness to the periphery of the image (night vision) cannot be ensured.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object thereof is to provide a soft contact lens capable of correcting myopia, hyperopia, astigmatism, presbyopia, and the like while sufficiently securing brightness around an image.

In order to solve the above problems, a soft contact lens of the present invention is worn on a cornea, the soft contact lens comprising: a light shielding portion for shielding incident light incident on a cornea; a lens main body having a diameter larger than that of the light shielding portion, covering a front surface and a rear surface of the light shielding portion, and composed of a light transmitting material capable of transmitting incident light, the light shielding portion including: a light shielding portion main body made of a light shielding material; an opening provided at a position including an optical axis connecting a center of a cornea and a center of a retina of the light shielding portion main body, the opening transmitting incident light; and a plurality of holes provided in the periphery of the opening of the light shielding portion main body and having a diameter smaller than that of the opening, the plurality of holes ensuring vision in a dark place and at night.

When the soft contact lens of the present invention is worn on the cornea, an image (light) is incident on the cornea through the lens front surface portion, the aperture, and the lens rear surface portion. An image incident on the cornea is imaged on the retina on the rear side of the vitreous body by the lens and the vitreous body which enter the inside of the eyeball through the cornea and the pupil. In this case, the aperture formed in the light shielding portion restricts the light flux to a certain amount, and therefore, an image can be formed on the retina at all times in both the case of looking far and the case of looking near.

Further, light around the pinhole enters from a plurality of fine holes formed around the pinhole, and forms an image on the retina through the cornea, the vitreous body, and the like. This ensures the brightness around the image. Further, the images of the small hole and the periphery of the light shielding portion are transmitted through a transmission portion (lens main body) provided in the periphery of the light shielding portion, incident on the cornea, and entered into the vitreous body inside the eyeball through the pupil, and formed on the retina on the back side of the vitreous body. This ensures a peripheral field of view around the image, and can obtain a field of view equivalent to that obtained with naked eyes.

The present invention can provide a soft contact lens that can correct any of myopia, hyperopia, astigmatism, and presbyopia by making a small hole in the center of a light shielding portion that shields incident light, and by using the depth of focus generated by the small hole. Further, according to the present invention, since a plurality of fine holes are bored around the small hole, it is possible to secure sufficient night vision (brightness) for the periphery of the image while securing the light shielding function.

Drawings

Fig. 1 is a perspective view showing an example of the structure of a soft contact lens according to an embodiment of the present invention.

Fig. 2 is a plan view showing an example of the structure of a soft contact lens.

Fig. 3 is a side view showing an example of the structure of a soft contact lens.

Fig. 4A is a cross-sectional view a-a of the soft contact lens shown in fig. 2.

Fig. 4B is an enlarged view of a main portion B of the soft contact lens shown in fig. 4A, which is surrounded by a dashed line.

Fig. 5 is a view showing a state in which a soft contact lens is worn on a cornea (state 1).

Fig. 6 is a diagram showing a state in which a soft contact lens is worn on the cornea (state 2).

Fig. 7A is a view for explaining the depth of focus at the time of distance viewing.

Fig. 7B is a diagram for explaining the focal depth when looking near.

Fig. 8 is a view for explaining the focal depth in the case of looking far away and looking near.

Detailed Description

The best mode for carrying out the invention (hereinafter referred to as "embodiment") will be described below.

Examples of structures of soft contact lenses

The soft contact lens 100 of the present invention can correct any of slight myopia, hyperopia, astigmatism, and presbyopia by utilizing the depth of focus generated by the pinhole 12 bored in the center of the light shielding portion 10, and can secure night vision (brightness) with respect to the periphery of an image by boring a large number of fine holes 14 around the pinhole 12. As shown in fig. 1 to 4A, the soft contact lens 100 includes: a light shielding portion 10 for shielding incident light incident on a cornea 20; and a lens body 16 for supporting the light-shielding portion 10.

The light shielding portion 10 includes a light shielding portion main body 18, a small hole 12, and a plurality of holes 14. The light shielding portion main body 18 is a member having a circular shape in plan view and having a curved surface such as a surface shape along the cornea 20 (see fig. 6), and the light shielding portion main body 18 is made of a light shielding material for shielding incident light incident on the cornea 20. The material of the light shielding portion main body 18 can be effectively used as a material used for a soft contact lens having a substantially iris color, which has been determined to have safety, and for example, an azo-based colorant (red-based) or a phthalocyanine-based colorant (blue-based) can be used. The light-shielding portion main body 18 is preferably extremely thin to prevent light from being shielded around the lens (the transmissive portion 16C described later, etc.).

The diameter D1 of the light shielding portion main body 18 is set, for example, in the range of 4.0mm to 9.0mm in consideration of the pupil diameter (the size of the pupil in a dark place) at the time of mydriasis that varies with age. This is because: when the diameter D1 of the light shielding portion main body 18 is smaller than 4.0mm, the area of a transmission portion 16C (see fig. 2) described later around the light shielding portion main body 18 is increased, and the peripheral field of view is widened, but when the pupil diameter is larger than the light shielding portion 10 at night or the like, peripheral light other than the light shielding portion 10 enters the center of the retina 26, and a halo phenomenon or flare may occur. When the diameter D1 of the light shielding portion main body 18 is larger than 9.0mm, the area of the transmission portion 16C of the lens main body 16 through which incident light is transmitted is reduced, and the peripheral visual field cannot be secured. That is, the visual field (visual sensation) equivalent to that in the case of naked eyes cannot be ensured.

The pinhole 12 is an example of an opening, and as shown in fig. 2 and 6, the pinhole 12 is provided at a position including an optical axis (eye axis) O connecting the cornea 20 and the retina 26, and passing through the center C of the light shielding portion main body 18 (lens main body 16). In order to prevent diffraction of incident light, the shape of the aperture 12 is preferably a perfect circle. The pinhole 12 has a function of limiting the light flux of the incident light entering the cornea 20 to a certain amount and imaging the light flux on the retina 26, and the pinhole 12 has an effect equivalent to the addition power (i.e., ADD power) of the multifocal lens depending on the size of the diameter D2 of the pinhole 12.

The diameter D2 of the orifice 12 is, for example, in the range of 1.0mm to 1.6 mm. When the diameter D2 of the small hole 12 was changed in the range of 1.0mm to 1.6mm, it was found that near vision corresponding to an addition degree of about 1.00D to 3.00D was obtained from the change in the size of the diameter. In addition, in the case where the diameter D2 of the small hole 12 is smaller than 1.0mm or larger than 1.6mm, the best near vision cannot be obtained. The reason for this can be considered as: as shown, even a non-adjusted lens results in a deeper depth of focus due to the changing beam.

As shown in fig. 2 and the like, the plurality of holes 14 are randomly or regularly formed between the hole periphery of the small hole 12 and the outer periphery of the light shielding portion main body 18, and the plurality of holes 14 have a function of ensuring brightness (night vision) by allowing light from the outside to enter the cornea 20. In particular, when the soft contact lens 100 is used at night or in a dark place, the light quantity can be effectively ensured. The narrower the pitch (interval) of the holes 14, the more sufficient brightness can be ensured. On the other hand, the wider the pitch of the holes 14, the higher the contrast of the image.

In order to prevent diffraction of incident light, the hole shape of the hole 14 is preferably a perfect circle. As shown in fig. 4A, the depth direction (penetration direction) of the hole 14 is inclined toward the retina 26 (along the one-dot chain line), whereby the incident light can be efficiently condensed on the retina 26.

The diameter D3 of the hole 14 is smaller than the diameter of the small hole 12, for example in the range of 0.17mm to 0.18 mm. This is because: in the case where the diameter of the hole 14 is less than 0.17mm, the aperture is too small to sufficiently introduce incident light, and night vision (brightness) cannot be secured. In addition, when the diameter of the hole 14 is larger than 0.18mm, the aperture diameter is too large, and halo and glare phenomena are generated by diffraction of light.

Here, the optimum diameter D3 of the hole 14 can be obtained from the relationship between the wavelength of light and the focal distance from the cornea 20 to the retina 26. As shown in fig. 6, when the diameter of the hole 14 is represented by Φ, the wavelength of incident light is represented by λ, and the distance from the cornea 20 to the retina 26 (eye axis length) is represented by the focal distance f, the diameter Φ of the hole 14 is obtained by the following equation (1).

Formula 1

Since the focal length f is usually 23mm to 24mm, the optimum diameter φ of the hole 14 is 0.176mm when a value of 23mm is substituted into the above equation (1), for example. When a value of 24mm is substituted as the focal length f in the above formula (1), the optimum diameter Φ of the hole 14 is 0.180 mm.

The lens body 16 is a member having a circular shape in plan view and having a curved surface (curvature) along the surface shape of the cornea 20, and the lens body 16 is made of a light-transmitting material that can transmit incident light. As the material of the lens body 16, hydroxyethyl methacrylate (HEMA), N-vinylpyrrolidone (N-VP), Dimethylacrylamide (DMAA), Glycidyl Methacrylate (GMA), Silicone Hydrogel (SH), and the like used for the water-containing soft contact lens can be preferably used. Further, as the material of the lens body 16, silicone rubber, butyl acrylate, and dimethyl siloxane lenses used for non-aqueous soft contact lenses or aqueous soft contact lenses can be preferably used. Further, as long as light can be transmitted, a colored material such as blue or red may be used instead of a colorless material.

Lens body 16 is used as a replacement, disposable soft contact lens. In the case of a person with light myopic, hyperopic, and astigmatic powers, vision for both distance and near viewing can be obtained without giving the power to the lens body 16. In other cases, the lens body 16 may be given powers corresponding to the near-sighted and far-sighted states of the user. As shown in fig. 2, the portion of the lens body 16 located at the peripheral portion of the light-shielding portion body 18 functions as a transmission portion 16C for introducing incident light to the cornea 20 to ensure a peripheral visual field.

The diameter D4 of the lens body 16 is larger than the diameter D1 of the light-shielding portion body 18, and as shown in FIG. 5, is larger than at least the diameter S1 (e.g., 12mm) of the cornea 20, and the diameter D4 of the lens body 16 is, for example, about 14 mm. This is because: when the diameter D4 of the lens main body 16 is smaller than the cornea diameter, the lens moves greatly on the cornea 20, and the center on the cornea 20 and the center C of the light shielding portion main body 18 are largely deviated, so that stable visual acuity cannot be ensured. In addition, in the case where the diameter D4 of the lens body 16 is greater than 14mm, it is difficult to wear the lens body 16 on the cornea 20. The lens body 16 having such a diameter is integrally formed with the light shielding portion body 18 so as to sandwich (cover) the front surface and the rear surface of the light shielding portion body 18 by the front surface portion and the rear surface portion constituting the lens body 16.

Next, the arrangement position of the light shielding portion 10 constituting the soft contact lens 100 of the present invention will be described in comparison with a conventional soft contact lens with an iris color. First, a conventional soft contact lens with an iris color will be described. In some cases, the colored portion (corresponding to the light shielding portion 10 of the present invention) of a conventional soft contact lens having an iris color is disposed (colored) so as to be exposed on the front surface or the rear surface of the lens. However, when the colored portion is disposed on the lens front surface, since the irregularities on the surface of the colored portion made of a material different from that of the lens main body are in contact with the eyelid conjunctiva (the back side of the eyelid), the friction of the lens front surface increases as compared with the case where the colored portion is disposed on the lens rear surface. Therefore, there are the following problems: during blinking, the lens body moves greatly due to friction between the eyelid conjunctiva and the colored portion, and the central axis of the soft contact lens is often displaced from the corneal center (optical axis), and the soft contact lens cannot be used in a stable state. In contrast, in the case where the colored portion is disposed on the lens rear surface, the friction of the lens rear surface increases as compared with the case where the colored portion is disposed on the lens front surface, so the colored portion of the lens main body easily adheres to the cornea, possibly causing a problem in terms of safety.

Therefore, in the soft contact lens 100 of the present invention, as shown in fig. 4A and 4B, the light shielding portion 10 is sandwiched between the front surface portion and the rear surface portion of the lens body 16, and the light shielding portion 10 is embedded in the lens body 16. That is, by disposing the light shielding portion 10 substantially at the center in the thickness direction of the lens body 16, a structure is formed in which the light shielding portion 10 is not exposed to the outside. This prevents excessive friction from occurring on the front and rear surfaces of the lens body 16, and therefore, it is possible to avoid the soft contact lens 100 from deviating from the optical axis, and to ensure stable eyesight. Further, since the lens body 16 can be prevented from sticking to the cornea, safety can be ensured.

Functional examples of soft contact lenses

Next, a functional example when the soft contact lens 100 according to the present embodiment is worn on an eyeball will be described. First, the normal depth of focus will be described in the case where a person with myopia sees far and the case where a person with presbyopia sees near. In the case where a myopic person looks far, the light entering the eyeball is not imaged at the correct position on the retina 26, but is imaged on the anterior side of the retina 26, as shown in fig. 7A. In addition, since the depth of focus is also shallow, the depth of focus is in front of the retina 26. In addition, as shown in fig. 7B, in the case where a person with presbyopia looks close, since the lens 22 loses elasticity and becomes hard, it is not imaged at a correct position on the retina 26 but imaged at the rear of the retina 26.

On the other hand, when the soft contact lens 100 of the present embodiment is worn on the cornea 20, an image (light) passes through the lens front surface portion 16a, the pinhole 12, and the lens rear surface portion 16b and enters the cornea 20 as shown in fig. 8. An image incident on the cornea 20 is imaged on a retina 26 on the back side of the vitreous body 24 via the cornea 20, pupil, and lens 22 into the vitreous body 24 inside the eyeball. Further, since the amount of light (speed of light) entering the eyeball is limited to a constant amount without being diffused by the pinhole 12, images can be formed at the same position on the retina 26 at all times in both the case of looking far and near. Therefore, by using the soft contact lens 100, a person having any of slight myopia, hyperopia, astigmatism, and presbyopia can be corrected by aligning the focal position on the retina 26, and therefore, the person can correct any of slight myopia, hyperopia, astigmatism, and presbyopia.

As shown in fig. 8, light is also incident from the plurality of fine holes 14 formed around the pinhole 12, and the light is imaged on the retina 26 at a position corresponding to the periphery of the image generated by the pinhole 12 via the cornea 20, the crystalline lens 22, the vitreous body 24, and the like, so that night vision (brightness) with respect to the image peripheral portion can be ensured. The peripheral image of the pinhole 12 and the light-shielding portion 10 is transmitted through the transmission portion 16C provided in the periphery of the light-shielding portion 10, enters the cornea 20, enters the vitreous body 24 inside the eyeball through the pupil, and is formed on the retina 26 on the back side of the vitreous body 24. Therefore, a peripheral field of view around the image obtained by the pinhole 12 can be secured, and a field of view equivalent to that obtained with naked eyes can be obtained.

As described above, according to the present embodiment, since the soft contact lens 100 utilizes the depth of focus generated by the pinhole 12, the near point can be seen with the minimum required accommodation force of the lens 22. Further, when the lens body 16 is not given the myopic power, the burden can be reduced even at the time of the near-point work. In addition, the soft contact lens 100 is effective not only in near vision but also in far vision requiring the accommodation power of the lens 22.

In addition, according to the present embodiment, since the pinhole 12 is used, only a very narrow range of the cornea 20 is used as the visual acuity, the soft contact lens 100 can be used even for corneal astigmatism and corneal irregular astigmatism, and therefore the soft contact lens 100 can be effectively used for astigmatism. Further, by setting the aperture diameter D2 of the small hole 12 in the range of 1.0mm to 1.6mm, an effect comparable to the addition degree of presbyopia can be obtained, and near vision comparable to the addition degree of a multifocal lens can also be obtained.

In addition, according to the soft contact lens 100 of the present embodiment, if necessary, near-sightedness or far-sightedness may be given to the lens body 16, or power may not be given to the lens body 16. Without providing power to the lens body 16, the epoch-making soft contact lens 100 can be provided which can see near without sacrificing distance vision, as in the case of a bifocal lens.

In addition, according to the present embodiment, since the plurality of fine holes 14 are formed around the small hole 12, the light shielding function (contrast of the image) can be ensured, and sufficient night vision (brightness) can be ensured for the periphery of the image. Further, since the periphery of the light shielding portion 10 is constituted by the transmission portion 16C through which light is transmitted, a peripheral field of view equivalent to that in the case of naked eyes can be secured.

Further, the soft contact lens 100 according to the present embodiment can correct presbyopia and the like by being worn on the cornea 20 as in a normal contact lens. Therefore, it is not necessary to implant the membrane into the cornea as in the case of the membrane of patent document 1, and therefore presbyopia and the like can be corrected more easily and safely.

The technical scope of the present invention is not limited to the above-described embodiments, and includes configurations obtained by variously modifying the above-described embodiments within a scope not departing from the gist of the present invention. For example, in the above example, the shape of the small holes 12 and the holes 14 is formed in a perfect circle shape in order to avoid diffraction of light, but the present invention is not limited thereto. The shape of the small holes 12 and 14 may be, for example, an ellipse, a rectangle, or the like.

Description of the reference numerals

100. Soft contact lenses; 10. a light shielding portion; 12. a small hole; 14. an aperture; 16. a lens body; 16C, a transmission part; 18. a light shielding portion main body; 20. a cornea; 26. a retina; o, optical axis.

Claims (7)

1. A soft contact lens to be worn on a cornea,

the soft contact lens includes:

a light shielding portion for shielding incident light incident on the cornea;

a lens main body having a diameter larger than the diameter of the light shielding portion, covering the front surface and the rear surface of the light shielding portion, and made of a light transmitting material capable of transmitting the incident light,

the light shielding portion includes:

a light shielding portion main body made of a light shielding material;

an opening provided in the light shielding portion main body at a position including an optical axis connecting a center of the cornea and a center of the retina, the opening allowing the incident light to pass therethrough;

and a plurality of holes provided in a portion of the light shielding portion main body around the opening and having a diameter smaller than a diameter of the opening, the plurality of holes ensuring eyesight in a dark place and at night.

2. A soft contact lens according to claim 1,

the diameter of the hole is 0.17 mm-0.18 mm.

3. A soft contact lens according to claim 2,

the diameter of the hole is obtained by the following equation, where φ represents the diameter of the hole, λ represents the wavelength of the incident light, and f represents the focal distance from the cornea to the retina.

(formula 1)

4. A soft contact lens according to any of claims 1 to 3,

by setting the diameter of the opening to be in the range of 1.0mm to 1.6mm, it is possible to obtain near vision equivalent to the addition degree of the multifocal lens, and to obtain effects of improving distance vision and correcting astigmatism which are affected by near vision and distance vision.

5. A soft contact lens according to any of claims 1 to 4,

the diameter of the light shielding part is smaller than that of the lens main body;

the lens body functions as a transmission section for introducing the incident light into the cornea to secure a peripheral visual field.

6. A soft contact lens according to claim 5,

the diameter of the light shielding part is 4.0 mm-9.0 mm;

the diameter of the lens body is about 14.0 mm.

7. A soft contact lens according to any of claims 1 to 6,

the lens body is composed of a front surface part and a rear surface part;

the light shielding portion is held between the front surface portion and the rear surface portion of the lens body.