A large-size defocused rigid gas permeable contact lens for preventing myopia

Abstract

The invention discloses a large-size defocused hard gas permeable contact lens for preventing myopia. The contact lens is made of a hard fluorosilicone acrylate material, has an oxygen permeability coefficient DK (Fatt; mmHg) of 60-150, and a Shore hardness of 80. The contact lens comprises a central optical zone, a first defocused zone, a second defocused zone, a transition zone and a landing zone from the center to the edge. The transition zone connects the second defocused zone and the landing zone and is located at the edge of the cornea. The landing zone is located in the sclera zone and serves as a load-bearing area of ​​the entire lens. The contact lens is in tangential contact with the sclera, and an angle is formed between the landing zone and the cornea. The contact lens is made of a hard fluorosilicone acrylate material with high oxygen permeability, can increase the oxygen permeability of the contact lens, and can correct high astigmatism without changing the shape of the cornea. While correcting vision through the optical zone, the contact lens itself adopts a "double defocus ring" design, and can also slow down the growth rate of axial myopia. The contact lens has broad application prospects and is conducive to popularization and application.

Description

Technical Field

[0001] The invention relates to the technical field of hard contact lenses, in particular to a large-size defocused hard gas-permeable contact lens for preventing myopia. Background Art

[0002] Most cases of myopia in adolescents are axial myopia, which is caused by congenital or acquired factors (such as not paying attention to eye hygiene), which makes the anterior-posterior diameter of the eyeball (i.e. the eye axis) longer, exceeding the normal average of 24mm, causing parallel light rays to focus in front of the retina after entering the eyeball, and the image cannot be clear. Clinically, myopia is generally divided into three categories according to the degree of myopia: low myopia (50 to 300 degrees), moderate myopia (325 to 600 degrees), and high myopia (myopia above 600 degrees). High myopia generally causes reduced distance vision, normal near vision, and reduced near vision in some cases. Most people with high myopia have a longer eye axis, which can cause a series of irreversible fundus lesions.

[0003] At present, most of the products on the market that control the growth of axial myopia are orthokeratology lenses, defocus soft lenses, and defocus frame lenses. Orthokeratology lenses compress the cornea, forming a defocus ring on the cornea, which is easy to cause damage to the cornea, and are only suitable for patients with less than 400 degrees. Patients with high myopia cannot wear orthokeratology lenses. The appearance of defocus soft lenses is not much different from that of contact lenses worn by adults, and the care methods are also the same. The fitting range of defocus soft lenses is relatively large, and generally can be fitted for myopia within 1000 degrees, but people with high astigmatism cannot wear defocus soft lenses, and defocus soft lenses are daily or biweekly disposable, with a slightly higher cost of use. They are mostly made of hydrogel materials and have poor oxygen permeability. Defocus frame lenses have the same principle as defocus soft lenses, which can control myopia well, but frame lenses are not beautiful and are very inconvenient for people who love sports. Therefore, it is urgent to develop a large-size defocus hard gas permeable contact lens for preventing myopia to solve the above technical problems.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a large-size defocused rigid gas permeable contact lens for preventing myopia, which is made of a highly oxygen-permeable rigid fluorosilicone acrylate material, can increase the oxygen permeability of the lens, and can correct high astigmatism without changing the shape of the cornea; while correcting vision through the optical zone, the lens itself adopts a "double defocus ring" design, which can also slow down the growth rate of axial myopia, and has broad application prospects, which is conducive to popularization and application.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a large-size defocused hard gas permeable contact lens for preventing myopia, which is made of hard fluorosilicone acrylate material, has an oxygen permeability coefficient DK (Fatt; mmHg) of 60-150, and a Shore hardness of 80. The lens is composed of a central optical zone, a first defocus zone, a second defocus zone, a transition zone and a landing zone from the center to the edge. The transition zone connects the second defocus zone and the landing zone and is located at the edge of the cornea. The landing zone is located in the sclera area, which serves as the load-bearing area of ​​the entire lens and contacts the sclera tangentially so that the contact lens can be well fixed on the sclera. The landing zone forms an angle with the cornea to facilitate the exchange of tears.

[0007] The central optical zone is designed with zero spherical aberration, and will not cause changes in the total spherical aberration of the human eye when wearing the lens. The front surface is designed as an aspherical surface, and the back surface is designed as a spherical surface with the average curvature radius of the anterior surface of the cornea corresponding to the area. The aspherical surface characterization equation is:

[0008]

[0009] Wherein, c is the reciprocal of the radius of curvature of the base sphere of the aspheric surface, x is the vertical distance from any point on the curve to the abscissa axis Z, A2i is the coefficient of the high-order term of the aspheric surface, m and n are both integers not less than 1, and n>m, and k is the cone coefficient;

[0010] The front surface of the first defocus zone is designed as an aspherical surface, and the back surface is designed as a spherical surface with an average curvature radius of the anterior surface of the cornea corresponding to the area. The aspherical surface characterization equation is the same as the aspherical surface characterization equation of the central optical zone. The refractive power of the aspherical surface is obtained by the following formula:

[0011]

[0012] P1 is the diopter of the first defocus zone of the lens, n L is the refractive index of the contact lens, n is the refractive index in the human eye, and r is the base radius of curvature of the back surface of the lens, where

[0013] The front surface of the second defocus zone is a progressive free-form surface design, and the rear surface is a spherical surface design with an average curvature radius of the corneal front surface corresponding to the region. The progressive free-form surface characterization equation is:

[0014]

[0015] Among them, c x 、c y are the basic spherical curvature radii of the progressive free-form surface in the x and y directions, k x , k y are the cone coefficients in the x and y directions respectively;

[0016] The diopter of the progressive free-form surface is obtained by the following formula:

[0017]

[0018] P2 is the diopter of the progressive free-form surface of the second defocus zone of the lens, n L is the refractive index of the lens, n is the refractive index in the human eye, r1 and r2 are the maximum and minimum radii of curvature of the progressive free-form surface of the lens, respectively.

[0019] The myopic defocus amount in the first defocus zone is a fixed value, and the myopic defocus amount in the second defocus zone increases with the increase of the refractive power of the central optical zone. The defocus amount is +2.5D-+10.00D, which is more in line with the non-spherical structure of the posterior part of the eyeball.

[0020] Preferably, the myopic defocus amount of the first defocus zone is 1.5D, 2.0D, 2.5D or 3.0D.

[0021] Preferably, the overall diameter of the lens is 12.5-14.5 mm.

[0022] Preferably, the diameter of the central optical zone of the lens is 3.5-5.0 mm.

[0023] Preferably, the diameter of the first defocusing area of ​​the lens is 4.5-6.0 mm.

[0024] Preferably, the diameter of the second defocus zone of the lens is 8.5-10.0 mm.

[0025] Preferably, the diameter of the lens transition zone is 10.0-11.5 mm.

[0026] Preferably, the lens landing zone diameter is 12.5-14.5 mm.

[0027] Preferably, the center thickness of the lens is 0.05-0.15 mm.

[0028] The invention provides a large-size defocused rigid gas permeable contact lens for preventing myopia, which has the following beneficial effects.

[0029] 1. The present invention is made of a hard fluorosilicone acrylate material with high oxygen permeability, which can increase the oxygen permeability of the lens and correct high astigmatism without changing the shape of the cornea; while correcting vision through the optical zone, the lens itself adopts a "double defocus ring" design, which can also slow down the growth rate of axial myopia.

[0030] 2. The lens material of the present invention contains polymers such as silicon and fluorine, which have higher oxygen permeability and can maintain the oxygen environment on the surface of the eye to avoid corneal hypoxia; the lens material is a non-hydrophilic material and will not absorb moisture on the surface of the eyeball, and is not likely to cause dry eye syndrome.

[0031] 3. The present invention can correct astigmatism within 3D through the tear lens formed between the lens and the cornea. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A front view of a large-size defocused rigid gas permeable contact lens for preventing myopia provided by the present invention;

[0033] Figure 2 A bottom view of a large-size defocused rigid gas-permeable contact lens for preventing myopia provided by the present invention;

[0034] Figure 3 Schematic diagram of light transmission when wearing ordinary rigid gas permeable contact lenses for myopia;

[0035] Figure 4 A schematic diagram of light path transmission when a myopic eye wears a large-size defocused rigid gas permeable contact lens provided by the present invention for preventing myopia.

[0036] In the figure:

[0037] 101. Central optical zone 102. First defocus zone 103. Second defocus zone 104. Transition zone 105. Landing zone 106. Back surface of lens. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with specific embodiments and drawings to help understand the content of the present invention.

[0039] like Figure 1-2 The figure shows a front view and a bottom view of a large-sized defocused hard gas permeable contact lens for preventing myopia provided by the present invention. The large-sized defocused hard gas permeable contact lens for preventing myopia is made of a hard fluorosilicone acrylate material, with an oxygen permeability coefficient DK (Fatt; mmHg) of 60-150 and a Shore hardness of 80. The lens is composed of a central optical zone, a first defocused zone, a second defocused zone, a transition zone and a landing zone from the center to the edge. The transition zone connects the second defocused zone and the landing zone and is located at the edge of the cornea. The landing zone is located in the sclera area, which serves as the load-bearing area of ​​the entire lens and is in tangential contact with the sclera so that the contact lens can be well fixed on the sclera. The landing zone forms an angle with the cornea to facilitate the exchange of tears.

[0040] The central optical zone is designed with zero spherical aberration, and will not cause changes in the total spherical aberration of the human eye when wearing the lens. The front surface is designed as an aspherical surface, and the back surface is designed as a spherical surface with the average curvature radius of the anterior surface of the cornea corresponding to the area. The aspherical surface characterization equation is:

[0041]

[0042] Wherein, c is the reciprocal of the radius of curvature of the base sphere of the aspheric surface, x is the vertical distance from any point on the curve to the abscissa axis Z, A2i is the coefficient of the high-order term of the aspheric surface, m and n are both integers not less than 1, and n>m, and k is the cone coefficient;

[0043] The front surface of the first defocus zone is designed as an aspherical surface, and the back surface is designed as a spherical surface with an average curvature radius of the anterior surface of the cornea corresponding to the area. The aspherical surface characterization equation is the same as the aspherical surface characterization equation of the central optical zone. The refractive power of the aspherical surface is obtained by the following formula:

[0044]

[0045] P1 is the diopter of the first defocus zone of the lens, n L is the refractive index of the contact lens, n is the refractive index in the human eye, and r is the base radius of curvature of the back surface of the lens, where

[0046] The front surface of the second defocus zone is a progressive free-form surface design, and the rear surface is a spherical surface design with an average curvature radius of the corneal front surface corresponding to the region. The progressive free-form surface characterization equation is:

[0047]

[0048] Among them, c x 、c y are the basic spherical curvature radii of the progressive free-form surface in the x and y directions, k x , k y are the cone coefficients in the x and y directions respectively;

[0049] The diopter of the progressive free-form surface is obtained by the following formula:

[0050]

[0051] P2 is the diopter of the progressive free-form surface of the second defocus zone of the lens, n L is the refractive index of the lens, n is the refractive index in the human eye, r1 and r2 are the maximum and minimum radii of curvature of the progressive free-form surface of the lens, respectively.

[0052] The myopic defocus amount in the first defocus zone is a fixed value, and the myopic defocus amount in the second defocus zone increases with the increase of the refractive power of the central optical zone. The defocus amount is +2.5D-+10.00D, which is more in line with the non-spherical structure of the posterior part of the eyeball.

[0053] Preferably, the myopic defocus amount of the first defocus zone is 1.5D, 2.0D, 2.5D or 3.0D. The total diameter of the lens is 12.5-14.5mm. The diameter of the central optical zone of the lens is 3.5-5.0mm. The diameter of the first defocus zone of the lens is 4.5-6.0mm. The diameter of the second defocus zone of the lens is 8.5-10.0mm. The diameter of the transition zone of the lens is 10.0-11.5mm. The diameter of the landing zone of the lens is 12.5-14.5mm. The center thickness of the lens is 0.05-0.15mm.

[0054] like Figure 3 The figure below is a schematic diagram of the light path transmission when myopic eyes wear ordinary rigid gas permeable contact lenses. Since the back surface of the eyeball is a spherical structure, hyperopia defocus is formed, and the peripheral light is imaged behind the retina, which is more likely to increase the degree of myopia.

[0055] like Figure 4 FIG. 1 is a schematic diagram of the light path transmission when a myopic eye wears a large-size defocused rigid gas permeable contact lens for preventing myopia provided by the present invention. Due to the defocus design of the lens, myopia defocus is formed, and the peripheral light is imaged in front of the retina, which can better control the growth of myopia.

[0056] The present invention is made of a hard fluorosilicone acrylate material with high oxygen permeability, which can increase the oxygen permeability of the lens and correct high astigmatism without changing the shape of the cornea; while correcting vision through the optical zone, the lens itself adopts a "double defocus ring" design, which can also slow down the growth rate of axial myopia. The lens material of the present invention contains polymers such as silicon and fluorine, and has a higher oxygen permeability, which can maintain the oxygen environment on the surface of the eye and avoid corneal hypoxia; the lens material is a non-hydrophilic material, which will not absorb moisture on the surface of the eyeball and is not easy to cause dry eyes. The present invention can correct astigmatism within 3D through the tear lens formed between the lens and the cornea.

[0057] The invention concept is described in detail using specific examples herein, and the description of the above embodiments is only used to help understand the core idea of ​​the invention. It should be pointed out that any obvious modification, equivalent substitution or other improvement made by a person of ordinary skill in the art without departing from the invention concept should be included in the protection scope of the present invention.

Claims

1. A large-size defocused rigid gas permeable contact lens for preventing myopia, characterized in that: Made of hard fluorosilicone acrylate material, the oxygen permeability coefficient DK is 60-150, the Shore hardness is 80, and the lens is composed of the central optical zone, the first defocus zone, the second defocus zone, the transition zone and the landing zone from the center to the edge. The transition zone connects the second defocus zone and the landing zone and is located at the edge of the cornea. The landing zone is located in the sclera area, which serves as the load-bearing area of ​​the entire lens and contacts the sclera tangentially. The landing zone forms an angle with the cornea; The central optical zone is designed with zero spherical aberration, its front surface is designed as an aspherical surface, and its back surface is designed as a spherical surface with an average curvature radius of the anterior surface of the cornea corresponding to the area. The aspherical surface characterization equation is: Where c is the reciprocal of the radius of curvature of the base sphere of the aspheric surface, x is the vertical distance from any point on the curve to the horizontal axis Z, and A 2i is the coefficient of the aspheric high-order term, m and n are both integers not less than 1, and n>m, k is the cone coefficient; The front surface of the first defocus zone is designed as an aspherical surface, and the back surface is designed as a spherical surface with an average curvature radius of the anterior surface of the cornea corresponding to the area. The aspherical surface characterization equation is the same as the aspherical surface characterization equation of the central optical zone. The refractive power of the aspherical surface is obtained by the following formula: P1 is the diopter of the first defocus zone of the lens, n L is the refractive index of the contact lens, n is the refractive index in the human eye, and r is the base radius of curvature of the back surface of the lens, where The front surface of the second defocus zone is a progressive free-form surface design, and the rear surface is a spherical surface design with an average curvature radius of the corneal front surface corresponding to the region. The progressive free-form surface characterization equation is: Among them, c x 、c y are the basic spherical curvature radii of the progressive free-form surface in the x and y directions, k x , k y are the cone coefficients in the x and y directions respectively; The diopter of the progressive free-form surface is obtained by the following formula: P2 is the diopter of the progressive free-form surface of the second defocus zone of the lens, n L is the refractive index of the lens, n is the refractive index in the human eye, r1 and r2 are the maximum and minimum radii of curvature of the progressive free-form surface of the lens, respectively. The myopic defocus amount in the first defocus zone is a fixed value, and the myopic defocus amount in the second defocus zone increases with the increase of the diopter of the central optical zone, and the defocus amount is +2.5D-+10.00D.

2. A large-size defocused rigid gas permeable contact lens for preventing myopia according to claim 1, characterized in that: The myopic defocus amount of the first defocus zone is 1.5D, 2.0D, 2.5D or 3.0D.

3. A large-size defocused rigid gas permeable contact lens for preventing myopia according to claim 2, characterized in that: The total diameter of the lens is 12.5-14.5mm.

4. A large-size defocused rigid gas permeable contact lens for preventing myopia according to claim 3, characterized in that: The diameter of the central optical zone of the lens is 3.5-5.0mm.

5. A large-size defocused rigid gas permeable contact lens for preventing myopia according to claim 4, characterized in that: The diameter of the first defocus area of ​​the lens is 4.5-6.0mm.

6. A large-size defocused rigid gas permeable contact lens for preventing myopia according to claim 5, characterized in that: The diameter of the second defocusing area of ​​the lens is 8.5-10.0mm.

7. A large-size defocused rigid gas permeable contact lens for preventing myopia according to claim 6, characterized in that: The diameter of the lens transition zone is 10.0-11.5mm.

8. A large-size defocused rigid gas permeable contact lens for preventing myopia according to claim 7, characterized in that: The lens landing area diameter is 12.5-14.5mm.

9. A large-size defocused rigid gas permeable contact lens for preventing myopia according to claim 8, characterized in that: The center thickness of the lens is 0.05-0.15mm.

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