A corneal contact lens that uses diffraction defocus to prevent and control myopia

Abstract

The present invention discloses a contact lens for preventing and controlling myopia using diffraction defocus, comprising: an optical body and a peripheral contact area; the optical body comprising a base curve posterior surface that contacts the cornea and a contact lens front surface having a diffraction area forming a bifocal pattern; the optical body is provided with a primary focus and a myopia defocus focus; a human eye model is established in Zemax, wherein the curvature of the optical zone of the base curve posterior surface of the contact lens is the same as the curvature of the corneal anterior surface of the human eye model, thereby designing the basic surface shape of the contact lens front surface and the diffraction area of the contact lens front surface. The contact lens designed in the present invention has a long-lasting shaping effect, and the defocus signal is stable when the human eye switches between near and far vision.

Description

Technical Field

[0001] The present invention relates to the technical field of lenses, and in particular to a corneal contact lens that utilizes diffraction defocus to prevent and control myopia. Background Art

[0002] To effectively prevent and control myopia in adolescents, experts and scholars have conducted extensive research and found that, in addition to defocus in the retinal macular area, hyperopic defocus in the retinal periphery is also a significant factor in the progression of myopia when wearing spherical or aspherical lenses to correct myopia. Internationally, it has been proven that suppressing hyperopic defocus in the retinal periphery can significantly prevent and control the progression of myopia in adolescents.

[0003] In recent years, the technology for controlling myopia defocus has been continuously developing. The mainstream products on the market are orthokeratology lenses and defocus lenses. Orthokeratology lenses use external forces to shape the cornea to form a visual area and a defocus ring, thereby achieving the effect of correcting vision and peripheral defocus. Compared with ordinary spherical (aspherical) glasses, orthokeratology lenses slow down the growth rate of the eye axis by 30% to 55%.

[0004] Existing defocus lenses use various defocusing methods to control the hyperopic defocus of the retina periphery under hyperopic conditions, but they cannot continuously form a stable defocus signal when the human eye switches between near and far vision. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the present invention provides a contact lens that uses diffraction defocus to prevent and control myopia. By utilizing the principles of diffraction spectroscopy and the theory of myopia defocus to prevent and control myopia, the lens forms a primary focal point and a myopia defocus point. This shaping effect lasts long, and the defocus signal remains stable as the eye switches between near and far vision.

[0006] To achieve the above effects, the technical solutions of the present invention are as follows:

[0007] The present invention provides a corneal contact lens for preventing and controlling myopia by utilizing diffraction defocus, comprising:

[0008] An optical body and a peripheral contact zone; the optical body includes a base curve posterior surface that contacts the cornea and a front surface of a corneal contact lens having a diffractive zone to form a bifocal focus; the optical body is provided with a primary focus and a myopic defocus focus; a human eye model is established in Zemax, wherein the curvature of the optical zone of the base curve posterior surface of the corneal contact lens is the same as the curvature of the corneal anterior surface of the human eye model;

[0009] Basic surface design of the front surface of corneal contact lenses:

[0010] The degree of myopia to be corrected and the base curve curvature radius are obtained, and the base curvature radius of the front surface of the corneal contact lens is calculated in the human eye model; an arbitrary spatial rectangular coordinate system is established with the vertex of the optical surface as the origin O and the optical axis as the Z axis, wherein the coordinate axis X and the coordinate axis Y of the coordinate system are tangent to the optical surface, and the base surface shape of the front surface of the corneal contact lens satisfies the equation on the YZ plane:

[0011]

[0012] Wherein, Z(y) is the curve expression of the optical surface on the two-dimensional coordinate plane YZ, c is the reciprocal of the radius of curvature of the base spherical surface of the optical surface, and y is the vertical distance from any point on the curve to the coordinate axis Z;

[0013] Design of diffraction zone on the front surface of contact lens:

[0014] The diffraction zone is provided with a diffraction ring zone. The diffraction zone on the front surface of the corneal contact lens is determined according to the position, radius and depth of the diffraction ring zone. The specific design steps are as follows:

[0015] According to the design requirements, the myopia defocus degree, the diffraction zone diameter d and the myopia defocus energy ratio k are determined;

[0016] The phase function φ(x) of the contact lens in the human eye model is determined according to the degree of myopia, and the expression is:

[0017] Φ(x)=ρ1x 2 +ρ2x 4

[0018] Where x represents the horizontal coordinate, and the unit is mm; ρ1 and ρ2 are the coefficients of the quadratic and quartic terms of the phase function respectively;

[0019] After compressing the phase function with a period of 2π, the position T(Φ) of the diffraction ring is obtained:

[0020]

[0021] In the formula, int() represents the rounding function;

[0022] When T(Φ)=0, that is, When Φ has multiple solutions, the solutions are recorded as φ(n). The value of x(n) corresponding to φ(n) is solved according to the phase function as the radius of the diffraction ring zone; then the number of diffraction ring zones n is determined according to the diameter d of the diffraction zone and the radius x(n) of the diffraction ring zone, that is:

[0023] d≥2*x(n)

[0024] Where x(n) is the radius of the nth diffraction ring of the contact lens;

[0025] According to the energy proportion k of myopic defocus and the diffraction efficiency, the depth h of the diffraction ring is determined:

[0026]

[0027] Where η is the diffraction efficiency, λ0 is the dominant wavelength of the contact lens;

[0028] The actual surface shape Z of the diffraction zone on the front surface of the contact lens is 衍 The expression is:

[0029]

[0030] Furthermore, the optical body 1 and the peripheral contact area 2 are an integrated structure, made of the same material and integrally formed.

[0031] Furthermore, the optical body 1 and the peripheral contact area 2 are made of hydrogel or silicone hydrogel and are compression molded.

[0032] Furthermore, the rear surface of the base arc is any one of a spherical surface, an aspherical surface, a toric surface, a super toric surface, and a free-form surface.

[0033] Furthermore, the energy proportion k of the myopic defocus of the corneal contact lens ranges from 30% to 70%.

[0034] Furthermore, the additional optical power of the corneal contact lens ranges from +2D to +8D.

[0035] Furthermore, the diameter of the corneal contact lens ranges from 13.5 mm to 15 mm, and the center thickness ranges from 0.02 mm to 0.2 mm.

[0036] Furthermore, the diameter of the diffraction zone ranges from 4 mm to 6 mm.

[0037] Furthermore, the curvature radius of the posterior surface of the base curve that contacts the cornea ranges from 8 mm to 9 mm.

[0038] Furthermore, the corneal contact lens is SCL, RGP or OK lens.

[0039] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0040] The present invention provides a main visual focus and a myopic defocus focus on the optical body to form a bifocal corneal contact lens, and designs the actual surface shape of the diffraction zone on the front surface of the corneal contact lens based on the diffraction ring zone, taking into account the optical effect while forming a long-term stable myopic defocus signal. As a day-band lens, the shaping effect is effective for a long time, and it is more suitable for adolescent myopic patients who use their eyes for a long time. In terms of effect, the myopic defocus imaging point is increased and the imaging is in front of the retina, avoiding the eye's self-adjustment to lengthen the eye axis, thereby achieving the purpose of preventing myopia. While correcting existing myopia, a myopic defocus signal is continuously and stably provided when the visual range is switched. When the human eye switches and adjusts the distance of vision, a stable defocus signal can be continuously formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG1 is an overall schematic diagram of a corneal contact lens provided by an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of a contact lens with a diffraction area of 6 mm provided by an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of a 5mm diffraction area of a corneal contact lens provided by an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of a corneal contact lens with a diffraction area of 4 mm provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0046] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0047] Example

[0048] This embodiment proposes a corneal contact lens that uses diffraction defocus to prevent and control myopia. Figure 1a and Figure 1b ,include:

[0049] An optical body 1 and a peripheral contact area 2; the optical body 1 includes a base curve posterior surface that contacts the cornea and a front surface of a corneal contact lens having a diffractive area to form a bifocal structure; the optical body 1 is provided with a primary focus and a myopic defocus focus; (determined according to design requirements, for example, if 1D of myopia requires a 2D myopic defocus, the primary focus is -1D and the myopic defocus is -3D.)

[0050] Based on Asian eye data, a human eye model was established in Zemax, where the curvature of the optical zone on the posterior surface of the contact lens base curve was the same as the curvature of the anterior corneal surface of the human eye model.

[0051] Basic surface design of the front surface of corneal contact lenses:

[0052] The degree of myopia to be corrected and the base curve curvature radius are obtained, and the base curvature radius of the front surface of the corneal contact lens is calculated in the human eye model; an arbitrary spatial rectangular coordinate system is established with the vertex of the optical surface as the origin O and the optical axis as the Z axis, wherein the coordinate axis X and the coordinate axis Y of the coordinate system are tangent to the optical surface, and the base surface shape of the front surface of the corneal contact lens satisfies the equation on the YZ plane:

[0053]

[0054] Wherein, Z(y) is the curve expression of the optical surface on the two-dimensional coordinate plane YZ, c is the reciprocal of the radius of curvature of the base spherical surface of the optical surface, and y is the vertical distance from any point on the curve to the coordinate axis Z;

[0055] Design of diffraction zone on the front surface of contact lens:

[0056] The phase expression is used to calculate the position of the diffraction ring zone. The diffraction ring zone is provided on the diffraction zone. The diffraction zone on the front surface of the corneal contact lens is determined based on the position, radius and depth of the diffraction ring zone. The specific design steps are as follows:

[0057] According to the design requirements, the myopia defocus degree, the diffraction zone diameter d and the myopia defocus energy ratio k are determined;

[0058] The phase function φ(x) of the contact lens in the human eye model is determined according to the degree of myopia, and the expression is:

[0059] Φ(x)=ρ1x 2 +ρ2x 4

[0060] Where x represents the horizontal coordinate, and the unit is mm; ρ1 and ρ2 are the coefficients of the quadratic and quartic terms of the phase function respectively;

[0061] After compressing the phase function with a period of 2π, the position T(Φ) of the diffraction ring is obtained:

[0062]

[0063] In the formula, int() represents the rounding function;

[0064] When T(Φ)=0, that is, When Φ has multiple solutions, the solutions are recorded as φ(n). The value of x(n) corresponding to φ(n) is solved according to the phase function as the radius of the diffraction ring zone; then the number of diffraction ring zones n is determined according to the diameter d of the diffraction zone and the radius x(n) of the diffraction ring zone, that is:

[0065] d≥2*(n)

[0066] Where x(n) is the radius of the nth diffraction ring of the contact lens;

[0067] According to the energy proportion k of myopic defocus and the diffraction efficiency, the depth h of the diffraction ring is determined:

[0068]

[0069] Where η is the diffraction efficiency, λ0 is the dominant wavelength of the contact lens;

[0070] The actual surface shape Z of the diffraction zone on the front surface of the contact lens is 衍 The expression is:

[0071]

[0072] There are two main types of products currently available on the market for myopia prevention and control: orthokeratology lenses and defocus lenses. Orthokeratology lenses are short-lived and have a relatively high incidence of complications, while defocus lenses are unable to generate a continuous and stable defocus signal when switching between viewing distances. Due to corneal elasticity, the visual field formed by orthokeratology lenses cannot achieve optimal vision correction, and the shaping effect is short-lived, failing to meet the needs of older students. Furthermore, orthokeratology lenses compress and reshape the cornea, increasing the likelihood of complications such as keratitis.

[0073] The contact lenses of the present invention offer a long wear life and produce a continuous and stable myopic defocus signal during wear, making them particularly suitable for adolescent myopic patients who spend a lot of time using their eyes. Due to the lens's defocus design, myopic defocus occurs, and peripheral light is imaged in front of the retina, which can better control the progression of myopia.

[0074] As a preferred technical solution, in this embodiment, the optical body 1 and the peripheral contact area 2 are an integrated structure, made of the same material and integrally formed.

[0075] As a preferred technical solution, in this embodiment, the optical body 1 and the peripheral contact area 2 are made of hydrogel or silicone hydrogel and are molded to facilitate wearing by the user.

[0076] As a preferred technical solution, in this embodiment, the rear surface of the base arc is any one of a spherical surface, an aspherical surface, a toric surface, a super toric surface, and a free-form surface.

[0077] The posterior base curve surface is also known as the optical zone. When wearing these myopia-control contact lenses, a certain tear layer remains between the posterior base curve surface and the anterior corneal surface to prevent prolonged direct contact between the lens body and the cornea, which can cause corneal hypoxia or corneal compression. For example, the posterior base curve surface can be configured as a spherical surface, an aspheric surface, a toric surface, a toric surface, or a freeform surface, depending on actual needs.

[0078] As a preferred technical solution, in this embodiment, the energy proportion k of myopic defocus of the corneal contact lens ranges from 30% to 70%. The higher the energy proportion k of myopic defocus, the better the myopia prevention and control effect. Relatively speaking, the better the myopia prevention and control effect, the worse the imaging effect of the main focus on the retina.

[0079] The energy of myopic defocus is represented as follows: the total energy is 100%, which is divided into two parts, one part forming the main focus, and the other part forming the myopic defocus focus, and the energy of the myopic defocus focus is the energy of the myopic defocus.

[0080] As a preferred technical solution, in this embodiment, the energy proportion k of the myopic defocus of the corneal contact lens ranges from 30% to 70%.

[0081] As a preferred technical solution, in this embodiment, the additional optical power of the corneal contact lens ranges from +2D to +8D. The greater the additional optical power of the defocused lens, the better the effect of preventing and controlling myopia.

[0082] As a preferred technical solution, in this embodiment, the diameter of the corneal contact lens ranges from 13.5 mm to 15 mm, and the center thickness ranges from 0.02 mm to 0.2 mm.

[0083] As a preferred technical solution, in this embodiment, the curvature radius of the posterior surface of the base curve that contacts the cornea ranges from 8 mm to 9 mm.

[0084] As a preferred technical solution, in this embodiment, the lens material of the present invention contains polymers such as silicon and fluorine, which has a 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.

[0085] In some examples, a contact lens may have a prescription area and a non-prescription area. When a contact lens is worn, light entering the eye through the prescription area is focused on the retina, while light entering the eye through the non-prescription area is focused in front of the retina. This can control or delay the progression of myopia while meeting the need for vision correction.

[0086] As a preferred technical solution, in this embodiment, the diameter of the diffraction zone ranges from 4 mm to 6 mm.

[0087] In some examples, based on the principle of myopic defocus to prevent and control myopia, a myopic defocus focus is formed under visual conditions to prevent and control myopia. The use environment of the contact lens of the present invention is mainly bright light environment, and the diameter range of the diffraction zone (4mm to 6mm) is determined based on the pupil diameter in bright light environment. The following uses the diffraction zone diameters of 6mm, 5mm, and 4mm as examples to calculate the phase of the contact lens in the human eye model.

[0088] When the diffraction zone diameter d = 6mm: determine the base arc curvature radius R 基 =8.2mm, the degree of myopia to be corrected is D 近 =4.0D, establish the human eye model in Zemax, and optimize the basic curvature radius R of the front surface of the corneal contact lens 前 =8.9mm; Then, determine the additional myopia defocus degree D required for myopia defocus 离焦 =2.0D and diffraction zone diameter d = 6mm, the number of diffraction rings is optimized to 8 in zemax, such as Figure 2 As shown, 1 is the optical body, and 2 is the diffraction area on the optical body;

[0089] The energy proportion of myopic defocus is k=40%, the myopic defocus usage level is level 1, and after calculation h=0.368, the phase expression is:

[0090] φ(x, y)=31.86x 2 +0.95x 4 .

[0091] When the diffraction zone diameter d = 5mm: determine the base arc curvature radius R 基 =8.4mm, the degree of myopia to be corrected is D 近 =6.0D, establish the human eye model in Zemax, and optimize the basic curvature radius R of the front surface of the corneal contact lens 前 =9.5mm; then, determine the additional myopia defocus degree D required for myopia defocus 离焦 =3.0D and diffraction zone diameter d = 5mm, the number of diffraction rings is optimized to 8 in zemax, such as Figure 3 As shown, 1 is the optical body, and 2 is the diffraction area on the optical body;

[0092] The energy proportion of myopic defocus is k=50%, the myopic defocus usage level is level 1, and after calculation h=0.438, the phase expression is:

[0093] φ(x, y)=20.89x 2 +1.35x 4 .

[0094] When the diffraction zone diameter d = 4 mm: First, determine the base arc curvature radius R 基 =8.6mm, the degree of myopia to be corrected is D 近 =2.0D, establish the human eye model in Zemax, and optimize the basic curvature radius R of the front surface of the corneal contact lens 前 =9mm; then, determine the additional myopia defocus degree D required for myopia defocus 离焦 =6.0D and diffraction zone diameter d = 4mm, the number of diffraction rings is optimized to 8 in zemax, such as Figure 4 As shown, 1 is the optical body, and 2 is the diffraction area on the optical body;

[0095] The energy proportion of myopic defocus is k=40%, the myopic defocus usage level is level 1, and after calculation h=0.368, the phase expression is:

[0096] φ(x, y)=10.45x 2 +1.26x 4 .

[0097] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A corneal contact lens for preventing and controlling myopia using diffraction defocus, characterized in that: include: An optical body (1) and a peripheral contact area (2); the optical body (1) comprises a base curve rear surface contacting the cornea and a corneal contact lens front surface having a diffraction area forming a bifocal focus; An optical body (1) is provided with a primary focus and a myopic defocus focus; a human eye model is established in Zemax, wherein the curvature of the optical zone on the posterior surface of the corneal contact lens base curve is the same as the curvature of the anterior surface of the cornea of the human eye model; Basic surface design of the front surface of corneal contact lenses: The degree of myopia to be corrected and the base curve curvature radius are obtained, and the base curvature radius of the front surface of the corneal contact lens is calculated in the human eye model; an arbitrary spatial rectangular coordinate system is established with the vertex of the optical surface as the origin O and the optical axis as the Z axis, wherein the coordinate axis X and the coordinate axis Y of the coordinate system are tangent to the optical surface, and the base surface shape of the front surface of the corneal contact lens satisfies the equation on the YZ plane: Wherein, Z(y) is the curve expression of the optical surface on the two-dimensional coordinate plane YZ, c is the reciprocal of the radius of curvature of the base spherical surface of the optical surface, and y is the vertical distance from any point on the curve to the coordinate axis Z; Design of diffraction zone on the front surface of contact lens: The diffraction zone is provided with a diffraction ring zone. The diffraction zone on the front surface of the corneal contact lens is determined according to the position, radius and depth of the diffraction ring zone. The specific design steps are as follows: According to the design requirements, the myopia defocus degree, the diffraction zone diameter d and the myopia defocus energy ratio k are determined; The phase function φ(x) of the contact lens in the human eye model is determined according to the degree of myopia, and the expression is: Φ(x)=ρ1x 2 +p2x 4 Where x represents the horizontal coordinate, and the unit is mm; ρ1 and ρ2 are the coefficients of the quadratic and quartic terms of the phase function respectively; After compressing the phase function with a period of 2π, the position T(Φ) of the diffraction ring is obtained: In the formula, int() represents the rounding function; When T(Φ)=0, that is, When Φ has multiple solutions, the solutions are recorded as φ(n). The value of x(n) corresponding to φ(n) is solved according to the phase function as the radius of the diffraction ring zone; then the number of diffraction ring zones n is determined according to the diameter d of the diffraction zone and the radius x(n) of the diffraction ring zone, that is: d≥2*x(n) Where x(n) is the radius of the nth diffraction ring of the contact lens; According to the energy proportion k of myopic defocus and the diffraction efficiency, the depth h of the diffraction ring is determined: Where η is the diffraction efficiency, λ0 is the dominant wavelength of the contact lens; The actual surface shape Z of the diffraction zone on the front surface of the contact lens is 衍 The expression is:

2. A contact lens for preventing and controlling myopia using diffraction defocus according to claim 1, characterized in that: The optical body (1) and the peripheral contact area (2) are an integrated structure, made of the same material and integrally formed.

3. The corneal contact lens for preventing and controlling myopia using diffraction defocus according to claim 2, characterized in that: The optical body (1) and the peripheral contact area (2) are made of hydrogel or silicone hydrogel and are molded.

4. The corneal contact lens for preventing and controlling myopia using diffraction defocus according to claim 1, characterized in that: The base arc rear surface is any one of a spherical surface, an aspherical surface, a toric surface, a super toric surface, and a free-form surface.

5. The corneal contact lens for preventing and controlling myopia using diffraction defocus according to claim 1, characterized in that: The energy proportion k of the myopic defocus of the corneal contact lens ranges from 30% to 70%.

6. The corneal contact lens for preventing and controlling myopia using diffraction defocus according to claim 1, characterized in that: The additional optical power of the corneal contact lens ranges from +2D to +8D.

7. The corneal contact lens for preventing and controlling myopia using diffraction defocus according to claim 1, characterized in that: The diameter of the corneal contact lens ranges from 13.5 mm to 15 mm, and the center thickness ranges from 0.02 mm to 0.2 mm.

8. The contact lens for preventing and controlling myopia using diffraction defocus according to claim 1, characterized in that: The diameter of the diffraction zone ranges from 4 mm to 6 mm.

9. The corneal contact lens for preventing and controlling myopia using diffraction defocus according to claim 1, characterized in that: The curvature radius of the posterior surface of the base curve contacting the cornea ranges from 8 mm to 9 mm.

10. A corneal contact lens for preventing and controlling myopia using diffraction defocus according to any one of claims 1 to 9, characterized in that: The corneal contact lens is SCL, RGP or OK lens.

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