Orthokeratology lens

Abstract

The present disclosure relates to an orthokeratology lens. The orthokeratology lens has a posterior surface for shaping the anterior surface of the cornea, the posterior surface having a base arc region and a reverse arc region. The curvature radius of the base arc area is gradually reduced from the center to the periphery; and / or the curvature radius of the reverse arc area is smaller than that of the base arc area and is gradually reduced from inside to outside. And / or the area with the preset width at the tail end of the base arc area is set as a transition arc area, and the curvature radius of the transition arc area is smaller than that of the base arc area and larger than that of the reverse arc area. Thus, the rear surface optical region can be lifted to increase the thickness of the central tear layer, so that the region is full of tear.

Description

Technical Field

[0001] The present disclosure relates to a corneal reshaping lens. Background Art

[0002] Orthokeratology lenses are worn at night and use physical effects such as mechanical compression, lens movement massage, and tear fluid hydraulics to flatten the curvature of the center of the cornea. This can temporarily reduce the degree of myopia, improve naked eye vision, and provide better visual effects even without glasses during the day. At the same time, orthokeratology lenses will form a defocus ring in the paracentral area of ​​the cornea. This defocus state can make myopia increase more slowly, thereby playing a role in controlling the development of myopia.

[0003] A large number of studies have confirmed that orthokeratology lenses play a positive role in controlling the progression of myopia. Studies have shown that compared with wearing ordinary frame glasses, the growth rate of the eye axis of adolescent myopic patients wearing orthokeratology lenses is significantly slowed down, and the deepening of myopia is also controlled to a certain extent. The overall effective rate is about 70%. After some patients insist on wearing orthokeratology lenses for a period of time, their myopia remains basically stable, or even decreases to a certain extent.

[0004] Safety is a key aspect of orthokeratology lenses. The base curve area (i.e., optical zone) of orthokeratology lenses is used to provide a shaping template for the cornea. It shapes the cornea through central positive pressure and peripheral negative pressure. In order to improve the shaping efficiency, the storage space of tears under the lens is sometimes compressed. Such efficiency improvement is actually not conducive to the health of the cornea. For example, when worn at night, the lens will adhere to the cornea and be difficult to move. It is also difficult to take off the lenses in the morning. This can cause corneal staining, corneal epithelial detachment, and even more serious adverse events.

[0005] In view of this, it is necessary to improve the design of orthokeratology lenses to effectively enhance the safety of lens wearing. Summary of the invention

[0006] A technical problem to be solved by the present disclosure is how to design a corneal reshaping lens that can improve the safety of lens wearing.

[0007] The present disclosure provides a corneal reshaping lens, which has a rear surface for shaping the front surface of the cornea, wherein the rear surface has a base curve zone and a reversal curve zone, wherein the curvature radius of the base curve zone gradually decreases from the center to the periphery; and / or the curvature radius of the reversal curve zone is smaller than the curvature radius of the base curve zone, and gradually decreases from the inside to the outside; and / or an area of ​​a predetermined width at the end of the base curve zone is set as a transition curve zone, wherein the curvature radius of the transition curve zone is smaller than the curvature radius of the base curve zone, and larger than the curvature radius of the reversal curve zone.

[0008] Optionally, the back surface parameters of the orthokeratology lens are configured so that the thickness of the tear layer after the shaping process is stabilized is within a first interval range, and the first interval range is a numerical range determined so that the surface free energy of the tear layer is not less than a first value and the cohesive force is not less than a second value, and the back surface parameters include at least one of the aspheric characteristic parameter value of the base curve zone, the aspheric characteristic parameter value of the reversal arc zone, and the width and curvature radius of the transition arc zone.

[0009] Optionally, the aspheric characteristic parameter value of the base curve region is configured to increase the sag of the base curve region by a third value.

[0010] Optionally, the eccentricity of the base arc region ranges from -0.45 to -1.25.

[0011] Optionally, the aspheric characteristic parameter value of the reverse arc zone is configured to increase the tear layer thickness by a third value

[0012] Optionally, the eccentricity of the reversal arc region ranges from -0.20 to -0.60.

[0013] Optionally, the width and the radius of curvature of the transition arc zone are configured to increase the thickness of the tear layer by a third value.

[0014] Optionally, the width of the transition arc zone is between 0.1 mm and 0.3 mm, and the difference between the curvature radius of the base arc zone and the curvature radius of the transition arc zone is between 0.35 mm and 3.00 mm.

[0015] Optionally, the third value is 7 μm to 10 μm.

[0016] Optionally, the back surface also has an adaptation arc zone and a peripheral arc zone, the adaptation arc zone includes a first adaptation arc zone and a second adaptation arc zone, the first adaptation arc zone is connected to the reversal arc zone, the second adaptation arc zone is connected to the peripheral arc zone, the first adaptation arc zone is parallel to the corresponding area of ​​the cornea, and the second adaptation arc zone gradually moves away from the cornea from the inside to the outside.

[0017] Optionally, the distance between the end of the second fitting arc zone and the cornea is between 5 μm and 40 μm.

[0018] Optionally, the radius of curvature of the second adaptation arc zone is 0.05 mm to 1.15 mm greater than the radius of curvature of the first adaptation arc zone; and / or the eccentricity of the second adaptation arc zone ranges from +0.20 to +0.90.

[0019] The present disclosure designs the curvature radius of the base curve area to gradually decrease from the center to the periphery; and / or designs the curvature radius of the inversion curve area to be smaller than the curvature radius of the base curve area and gradually decrease from the inside to the outside; and / or sets the area with a predetermined width at the end of the base curve area as the transition curve area, and the curvature radius of the transition curve area is smaller than the curvature radius of the base curve area and larger than the curvature radius of the inversion curve area. In this way, the optical zone of the rear surface can be lifted, the thickness of the central tear layer can be increased, and the tear filling in this area can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components in the exemplary embodiments of the present disclosure.

[0021] Figure 1 A simplified cross-sectional view of a conventional orthokeratology lens is shown.

[0022] Figure 2 A simplified cross-sectional view of a corneal reshaping lens according to one embodiment of the present disclosure is shown.

[0023] Figure 3 A simplified cross-sectional view of a corneal reshaping lens according to another embodiment of the present disclosure is shown.

[0024] Figure 4 A simplified cross-sectional view of a corneal reshaping lens according to another embodiment of the present disclosure is shown.

[0025] Figure 5 A simplified cross-sectional view of a corneal reshaping lens according to another embodiment of the present disclosure is shown.

[0026] Figure 6 A simplified cross-sectional view of a corneal reshaping lens according to another embodiment of the present disclosure is shown.

[0027] Figure 7 A comparison chart of the fluorescent staining of the orthokeratology lens of the present invention and the conventional orthokeratology lens is shown. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0029] Figures 1 to 6Only the rear surface of the orthokeratology lens for shaping the front surface of the cornea is shown. Because the present disclosure is not concerned with the design of the front surface of the orthokeratology lens, in order not to cause interference, the front surface is omitted in the figure. Those skilled in the art should understand that the present disclosure is suitable for adopting any appropriate front surface design. For example, the present disclosure is not only suitable for orthokeratology lenses worn at night, but also suitable for orthokeratology lenses worn during the day.

[0030] In addition, various value ranges described in the text may include two endpoint values.

[0031] Figure 1 A simplified cross-sectional view of a conventional orthokeratology lens is shown.

[0032] like Figure 1 As shown in the figure, the back surface of the orthokeratology lens has four zones: the base curve (BC) zone, and the reverse curve (RC) zone, the alignment curve (AC) zone and the peripheral curve (PC) zone connected in sequence. The base curve zone is located in the center of the orthokeratology lens. The base curve zone can also be called the back surface optical zone. The reverse curve zone is adjacent to the base curve zone. The peripheral curve zone is adjacent to the alignment curve zone and is located at the outermost periphery of the lens.

[0033] The back surface of orthokeratology lenses can be roughly divided into a central area and a peripheral area. The base curve area and the reverse curve area can be classified as the central area. The adaptation curve area and the peripheral curve area can be classified as the peripheral area.

[0034] The present disclosure proposes that the central area (base curve area and / or inversion curve area) can be optimized and designed to slightly elevate (i.e., lift) the optical zone (i.e., base curve area) to increase the thickness of the central tear layer, thereby filling the area with tears.

[0035] The present disclosure also proposes that by optimizing the design of the peripheral area (such as the fitting arc area), a soft edge with no obvious transition can be formed, so that the tears under the lens are filled and the tear exchange is soft and smooth.

[0036] In some preferred embodiments, the above two optimization designs can be used simultaneously to effectively improve the safety of lens wearing without damaging the shaping efficiency.

[0037] 1. Optimized design for the central area

[0038] The goal of optimizing the central region is to slightly elevate the posterior surface optical zone to increase the central tear layer thickness.

[0039] When fitting orthokeratology lenses, optometrists or fitters may increase the degree of overcorrection based on the wearer's expectations of the shaping effect and efficiency, that is, reducing the base curve curvature by 0.25 to 1.00D, that is, increasing the base curve curvature radius by 0.04 to 0.30mm. Taking the classic spherical four-arc VST design orthokeratology lenses as an example, this will result in a reduction of the tear layer in the shaping area by 4μm to 18μm. If the tear layer at the center vertex of the cornea is originally 10μm, such parameter adjustment will cause contact and overpressure of the center vertex of the lens, causing corneal health problems.

[0040] The textbooks recommend the ideal thickness of the tear layer in the center of orthokeratology lenses to be 5μm to 20μm. This is a recommendation based on the design of the old generation of products. The main consideration is still to balance the relationship between shaping efficiency and corneal health. However, as mentioned earlier, in actual application, the lenses may tend to sacrifice some corneal health to improve shaping efficiency.

[0041] Therefore, it is very necessary to optimize the tear layer. The main purpose of optimizing the tear layer is: on the one hand, to ensure the shape of the tear layer, so that the tear layer forms an effective negative pressure and ensures the shaping efficiency; on the other hand, to ensure the thickness of the tear layer at all locations, so that the tears under the lens are always full and lubricated, ensuring the safety and health of the cornea.

[0042] In order to balance the above two objectives, the present invention studies the shaping principle of orthopaedic lenses.

[0043] The shaping force of orthokeratology lenses that deform the cornea mainly comes from the surface tension of the tear layer under the lens. Therefore, quantitative calculation and optimization of the surface tension of the tear layer under the lens are very important for the design of orthokeratology lenses. Unfortunately, the industry has been concerned about the tear pressure under orthokeratology lenses for a long time, but there is no recognized detection method. It can only be evaluated non-quantitatively through the shaping rate and the patient's wearing comfort.

[0044] The surface tension of the tear layer is determined by the gap between the cornea and the orthokeratology lens, that is, the shape of the tear layer formed. If the tear layer is too thin and dispersed, it is impossible to form a concentrated intermolecular attraction within the tears, resulting in too little negative pressure. Conversely, if the tear layer is too thick and concentrated, the intermolecular attraction within the tears has almost reached internal balance, making it difficult to exert an impact on the cornea.

[0045] Specifically, the relationship between tear shape and shaping can be understood in terms of surface free energy and intermolecular cohesive forces.

[0046] The surface free energy of a liquid refers to the increment of the free energy of the system when the unit surface area is increased under constant temperature and constant pressure conditions. It is a potential energy that reflects the high-energy state of the molecules on the surface of the liquid. From a molecular level, the forces acting on the molecules inside the liquid by the surrounding molecules are symmetrical and have lower energy. However, the surface molecules are in a relatively unstable and high-energy state due to the asymmetric forces. The surface free energy is used to measure the additional energy generated by the existence of the surface, which affects the balance of intermolecular forces. It is calculated using the following formula:

[0047] G8=γA

[0048] Where G8 is the surface free energy, γ is the surface tension coefficient, and A is the liquid surface area.

[0049] For given liquid composition and environmental conditions, the surface tension coefficient γ of the liquid remains unchanged, and the surface free energy of the liquid is determined by its surface area. The larger the surface area, the higher the surface free energy.

[0050] According to the second law of thermodynamics, the system tends to move toward the lowest energy state. In order to reduce the surface free energy, the liquid tends to reduce the surface area. This is just like in the liquid surface phenomenon, the liquid always tends to minimize its surface area. Liquids naturally have a tendency to release energy to reduce potential energy, that is, to shrink inwards and reduce the surface area. If there is no external force, it will eventually shrink into a perfect sphere.

[0051] The cohesion of a liquid refers to the force of attraction between liquid molecules. It is a manifestation of intermolecular forces in liquids, which makes liquid molecules tend to gather together and prevents liquid molecules from separating from each other. The cohesion of a liquid mainly comes from the van der Waals force between molecules, that is, the mutual attraction caused by the polarity or instantaneous polarity between molecules, including dispersion force, induction force and orientation force.

[0052] a. Dispersion force formula:

[0053]

[0054] where I1 and I2 are the ionization energies of the two interacting molecules, α1 and α2 are their polarizabilities, and r is the distance between the molecular centers of mass.

[0055] b. Induction force formula:

[0056]

[0057] Where α is the polarizability, μ1 is the dipole moment of the polar molecule, and r is the distance between the centers of mass.

[0058] c. Orientation force formula:

[0059]

[0060] Where μ1 and μ2 are the dipole moments of the two polar molecules, r is the distance between the centers of mass, k is the Boltzmann constant, and T is the thermodynamic temperature.

[0061] According to the formula, at the microscopic level, the van der Waals force is negatively correlated with the distance between molecules, and at the macroscopic level, the higher the degree of dispersion of the liquid, the weaker its inward contraction force.

[0062] For orthokeratology lenses, the cohesive effect of tears under the lenses is the main source of negative pressure. The surface free energy of tears is the energy that tears can release to the cornea, which determines the reshaping effect; while the cohesive force of tears is the force that tears can exert on the corneal epithelium, which determines the reshaping efficiency.

[0063] Therefore, when designing the sub-mirror tear of orthokeratology lenses, in order to take into account both the shaping effect and shaping efficiency, it is necessary to comprehensively consider the tear surface area, volume, and concentration to form appropriate surface free energy and cohesion. In addition, since the shaping of orthokeratology lenses is a continuous and dynamic process, as the shaping progresses, the central tear layer will gradually decrease until it reaches equilibrium, so the sub-mirror tear morphology during and after shaping should be carefully considered. For example, when the orthokeratology lens is over-pressurized, there is almost no tear in the area of ​​about 2mm to 4mm in diameter in the actual center, and this area will further expand after shaping. The surface area, volume, and concentration of the sub-mirror tear are small, that is, the surface free energy and cohesion are poor. At this time, the shaping mainly relies on the mechanical pressure generated by the direct contact between the lens and the cornea, which is easy to cause corneal damage.

[0064] When the center of the orthokeratology lens is slightly lifted in an appropriate manner, a suitable tear layer will exist under the lens regardless of before or after shaping, always ensuring a certain degree of surface area, volume and concentration of tears under the lens, with good surface free energy and cohesion, without losing the shaping effect and shaping efficiency. And because the lens is not in direct contact with the cornea, the mechanical pressure is weakened, effectively protecting the health of the cornea.

[0065] In view of this, the present disclosure proposes that the back surface parameters of the orthokeratology lens can be configured so that the thickness of the tear layer after the shaping process is stabilized (i.e., after the central tear layer is balanced) is within the first interval range. The first interval range is a numerical range determined so that the surface free energy of the tear layer is not less than the first value and the cohesion is not less than the second value. That is, the first interval range is used to ensure that the tear layer has good surface free energy and cohesion after the shaping process is stabilized. The first value and the second value can be determined according to actual conditions (such as experimental data). As described above, the surface free energy and cohesion of the tear layer are related to the shape of the tear layer (such as surface area, volume, concentration), and the thickness of the tear layer can be regarded as the determining factor of the shape of the tear layer when other conditions remain unchanged. Therefore, in order to make the tear layer have good surface free energy and cohesion after the shaping process is stabilized, the appropriate tear layer thickness (i.e., the first interval range) can be derived by formula, and then the back surface parameters of the orthokeratology lens can be configured so that the thickness of the tear layer after the shaping process is stabilized is within the first interval range.

[0066] The back surface parameters may include at least one of the aspheric characteristic parameter value of the base curve area, the aspheric characteristic parameter value of the reverse curve area, the width and the curvature radius of the transition curve area. That is, by configuring the base curve area, the reverse curve area, and the transition curve area individually or in combination, the thickness of the tear layer can be increased.

[0067] The following are three exemplary methods for raising the optical zone of the rear surface (i.e., increasing the thickness of the central tear layer). It should be understood that these three methods can be used one by one or in combination. For example, any two or three methods can be used in combination.

[0068] Method 1: Design the base curve area as an aspheric surface with a negative e value

[0069] The base curve area can be designed as an aspherical surface, and the aspherical characteristic parameter value makes the curvature radius of the base curve area gradually decrease from the center to the periphery. The aspherical characteristic parameter value can refer to the e value. e represents eccentricity. The positive or negative value of the e value indicates whether an oblate curve or an elongated curve is used. A positive e value indicates that an elongated curve is used, and the curvature radius gradually increases from the inside to the outside. A negative e value indicates that an oblate curve is used, and the curvature radius gradually decreases from the inside to the outside.

[0070] The purpose of designing the base curve area as an aspheric surface with a negative e-value is to gradually reduce the radius of curvature of the base curve area from the center to the periphery. In this way, the peripheral defocus area and defocus amount are increased without affecting the patient's visual effect; at the same time, compared with the base curve area using a spherical design (or an aspheric design but with a positive e-value), the optical zone sagittal height of the lens (i.e., the base curve zone sagittal height) is higher, which is equivalent to the optical zone being slightly lifted (i.e., the center of the lens is arched), so that the tear layer between the lens and the cornea can increase a certain thickness, for example, it can be thickened by about 5μ to 15μm. In this way, for the tears behind the lens formed after wearing orthokeratology lenses, it helps to promote the exchange of tears behind the lens to maintain corneal integrity and reduce corneal damage caused by orthokeratology lenses.

[0071] Figure 2 A simplified cross-sectional view of a corneal reshaping lens according to one embodiment of the present disclosure is shown.

[0072] See also Figure 2 , the dotted line corresponding to the BC area in the lens indicates that the BC area adopts a spherical design, and the solid line corresponding to the BC area in the lens indicates that the BC area adopts an aspherical design with a negative e value. Compared with the spherical design of the base curve area, by designing the base curve area as an aspherical surface with a negative e value, the BC area sagittal height can be increased and the central tear layer thickness can be improved.

[0073] There is a certain functional relationship between the aspheric characteristic parameter value (e value) and the aspheric sag, which can be represented by the aspheric surface-sag function. Therefore, for the desired BC area sag, the aspheric surface-sag function can be used to calculate the aspheric characteristic parameter value required to make the BC area have the sag.

[0074] That is to say, the aspheric characteristic parameter value of the BC zone can be determined according to the desired BC zone sagitta. Exemplarily, the aspheric characteristic parameter value of the base curve zone can be configured to increase the base curve zone sagitta (i.e., the aspheric surface sagitta) by a third value. Increasing the base curve zone sagitta by a third value is equivalent to increasing the tear layer thickness by a third value. For example, the aspheric characteristic parameter value of the base curve zone can be determined with the goal of increasing the base curve zone sagitta by 5μm to 15μm. Increasing the base curve zone sagitta by a third value may refer to increasing the base curve zone sagitta by a third value compared to the base curve zone sagitta corresponding to the original design.

[0075] The aspheric surface-sag function can be written as:

[0076]

[0077] Among them, Sag(r) represents the sag of the aspheric surface, c is the vertex curvature of the aspheric surface (1 / vertex curvature radius), and r is the half chord length of the aspheric surface. When using this formula to calculate the sag of the BC area, z is the sag of the BC area, c is the curvature at the center of the BC area, and r is the diameter of the BC area / 2. The Q value and the e value have a square relationship with opposite signs.

[0078] The relationship between Q value and e value can be expressed by the following formula:

[0079]

[0080] The BC zone sagitta is positively correlated with the thickness of the central tear layer. According to the BC zone sagitta that meets the requirements, the above formula can be used to reversely calculate the expected e-value range. Exemplarily, the e-value range of the BC zone calculated to raise the posterior surface optical zone by 5 μm to 15 μm is -0.45 to -1.25, such as -0.45, -0.50, -0.55, -0.60, -0.65, -0.70, -0.75, -0.80, -0.85, -0.90, -0.95, -1.00, -1.05, -1.10, -1.15, -1.25, or any value within this range, or any value within any sub-range within the range of -0.45 to -1.25, and the sub-range can be, for example, a range consisting of any two values ​​listed here as endpoint values.

[0081] For example, when the e value is selected as -0.45, the optical zone of the back surface is raised by 5μm, which is slightly higher than the design of the old generation of orthokeratology lenses, and the change in the central tear layer thickness of some diopters is not obvious.

[0082] For example, when the e value is selected as -1.25, the optical zone of the back surface is raised by 15μm, which is a larger elevation than the old generation of orthokeratology lens design. The central tear layer thickness of some diopters reaches 35μm.

[0083] In addition, it has been found that when the rear surface optical zone is lifted by about 7μm to 10μm, the lifting amount is more appropriate compared to the old generation of orthokeratology lenses, and each degree shows a reasonable lifting value. Therefore, the third value can be 7μm to 10μm. In other words, the e-value of the base curve zone can be determined with the goal of increasing the base curve zone sagitta by 7μm to 10μm. That is, a preferred range of e-values ​​for the base curve zone is the e-value range corresponding to increasing the base curve zone sagitta by 7μm to 10μm.

[0084] Method 2: Design the reversal arc area as an aspheric surface with a negative e value

[0085] Figure 3 A simplified cross-sectional view of a corneal reshaping lens according to another embodiment of the present disclosure is shown.

[0086] See also Figure 3 , the dotted line corresponding to the RC zone in the lens indicates that the RC zone adopts a spherical design, and the solid line corresponding to the RC zone in the lens indicates that the RC zone adopts a non-spherical design and has a negative e-value. The BC zone can still adopt a spherical design. Compared with the spherical design of the RC zone, by designing the RC zone as a non-spherical surface with a negative e-value, the BC zone can also be slightly lifted, thereby increasing the thickness of the central tear layer. Therefore, the reversal arc zone can be designed as a non-spherical surface, and the aspherical characteristic parameter value (ie, the e-value) makes the curvature radius of the reversal arc zone smaller than the curvature radius of the base arc zone, and gradually decreases from the inside to the outside. In this way, the purpose of lifting the BC zone and increasing the thickness of the central tear layer can also be achieved.

[0087] The aspheric characteristic parameter value of the reverse arc area can be configured to increase the tear layer thickness by a third value. The third value can be, for example, 7 μm to 10 μm mentioned above. Increasing the tear layer thickness by a third value can refer to increasing the tear layer thickness by a third value compared to the tear layer thickness corresponding to the original design.

[0088] Exemplarily, the aspheric characteristic parameter value of the reverse arc zone can be configured to make the tear layer thickness greater than or equal to the fourth value. The fourth value can be flexibly set according to actual conditions. For example, the central tear thickness of the conventional OK lens and the cornea is about 10 μm. Taking the tear layer thickness thickened by about 5 μm to 15 μm compared with the conventional thickness as an example, the fourth value can be set to about 15 μm to 25 μm.

[0089] According to the value of the RC zone expected to thicken the tear layer by lifting the BC zone, the eccentricity of the RC zone that meets the requirements can be calculated. Exemplarily, the eccentricity of the RC zone ranges from -0.20 to -0.60, such as -0.20, -0.25, -0.30, -0.35, -0.40, -0.45, -0.50, -0.55, -0.60, or any value within the range.

[0090] For example, when the e value is selected as -0.20, the optical zone of the back surface is raised by 5μm, which is slightly higher than the design of the old generation of orthokeratology lenses, and the change in the central tear layer thickness of some diopters is not obvious.

[0091] For example, when the e value is selected as -0.60, the optical zone of the back surface is raised by 15μm, which is a larger elevation than the old generation of orthokeratology lens design. The central tear layer thickness of some diopters reaches 35μm.

[0092] For example, when the preferred e value is -0.30 to -0.40, the lifting of the optical zone on the back surface is about 7 μm to 10 μm, which is more appropriate than the design of old-generation orthokeratology lenses, and each degree shows a reasonable lifting value.

[0093] Method 3: Set the end of the base arc area as the transition arc area

[0094] Figure 4 A simplified cross-sectional view of a corneal reshaping lens according to another embodiment of the present disclosure is shown.

[0095] See also Figure 4 , the area of ​​predetermined width at the end of the BC zone can be set as the transition arc (TC) zone. For example, the width of about 0.1mm to 0.3mm at the end of the BC zone can be set as the transition arc zone. That is, the width of the transition arc zone can be between 0.1mm and 0.3mm, such as 0.10mm, 0.15mm, 0.20mm, 0.25mm, 0.30mm, or any value within this range. The transition arc zone can be divided into multiple transition arcs, wherein the radius of curvature of part or all of the multiple transition arcs is smaller than the radius of curvature of the base arc zone, and larger than the radius of curvature of the reversal arc zone. By transforming the area of ​​predetermined width at the end of the BC zone into the TC zone, the BC zone can also be lifted to a certain extent, thereby increasing the thickness of the central tear layer.

[0096] The width and curvature radius of the transition arc area are configured to increase the tear layer thickness by a third value, which may be, for example, the 7-10 μm mentioned above.

[0097] Exemplarily, the width and the radius of curvature of the transition arc region may be configured to make the tear layer thickness greater than or equal to a fourth value. For the fourth value, please refer to the above description.

[0098] When making orthokeratology lenses, the width and curvature radius of the TC zone can be calculated based on the expected value of thickening the tear layer by lifting the BC zone. For example, the width of the transition arc zone is between 0.1 mm and 0.3 mm, and the difference between the curvature radius of the base arc zone and the curvature radius of the transition arc zone is between 0.35 mm and 3.00 mm.

[0099] For example, when the width of the TC zone is set to 0.1mm, the difference between the curvature radius of the base arc zone (i.e., the base arc zone at the position connected to the transition zone) and the curvature radius of the transition arc zone can be selected from 0.70mm to 3.00mm; when the width of the TC zone is set to 0.2mm, the difference between the curvature radius of the base arc zone and the curvature radius of the transition arc zone can be selected from 0.40mm to 1.80mm; when the width of the TC zone is set to 0.3mm, the difference between the curvature radius of the base arc zone and the curvature radius of the transition arc zone can be selected from 0.35mm to 1.40mm.

[0100] According to clinical data, when the orthokeratology lenses are improved by the above three methods and the thickness of the central tear layer under the lens is raised by 5 to 15 μm, a full tear layer can be observed under the lens through fluorescent staining. During the 12-month observation period, the patients had good wearing comfort and the orthokeratology efficiency was not impaired by the increase in the thickness of the central tear layer under the lens.

[0101] In addition, when the central tear layer under the lens exceeds 35 μm, the shaping efficiency of the orthokeratology lens will be greatly reduced, and the improvement through the above three methods or their combination methods cannot compensate for the damaged shaping efficiency due to the excessive increase in the thickness of the central tear layer under the lens. Therefore, when the tear layer thickness is increased by using the above three methods or their combination methods, the tear layer thickness can be increased with the restriction that the central tear layer under the lens does not exceed 35 μm.

[0102] In a small-scale test, the above three methods can be used alone or in combination. It has been verified that the following embodiments with different parameter combinations have similar and improved fitting characteristics, shaping efficiency and comfort:

[0103] a. The e value of the base arc area is -0.45, -0.55, or -0.70;

[0104] b. The e value of the reversal zone is -0.20, -0.30, or -0.40;

[0105] c. The width of the transition zone is 0.20 mm, and the radius of curvature is the base arc radius minus 0.40 mm, or 0.60 mm.

[0106] It should be known that based on the above-mentioned optimized design of the present disclosure, even if additional overcorrection is given, it will not cause overpressure and will not cause corneal health problems. Therefore, the orthokeratology lens of the present disclosure may refer to an orthokeratology lens with an additional overcorrection degree.

[0107] 2. Optimized design for surrounding areas

[0108] The matching arc area can adopt a double matching arc design to form a soft edge warping without obvious transition with the surrounding arc area.

[0109] The fitting arc zone includes a first fitting arc zone and a second fitting arc zone. The first fitting arc zone is a fitting arc close to the center of the lens, and the first fitting arc zone is connected to the reverse arc zone. The first fitting arc zone is designed to be parallel to the corresponding area of ​​the cornea. The second fitting arc zone is a fitting arc close to the edge of the lens, and the second fitting arc zone is connected to the edge arc zone. The second fitting arc zone is designed to gradually move away from the cornea from the inside to the outside, so as to form a soft edge warping without obvious transition with the peripheral arc zone.

[0110] The peripheral arc area of ​​orthokeratology lenses is usually a fixed width, such as 0.3 to 0.5 mm wide. Its radius of curvature determines the edge warping of the lens, thereby affecting the exchange of tears under the lens, the mobility of the lens, and even the comfort. The present invention designs the second adaptation arc area to gradually move away from the cornea from the inside to the outside, so that the second adaptation arc area can be combined with the peripheral arc area into an ultra-wide edge warping, which is softer and has no obvious transition, so that the tears under the lens are filled and the tear exchange is soft and smooth.

[0111] Exemplarily, the distance between the end of the second adaptation arc zone (the position connected to the peripheral arc zone) and the cornea can be between 5μm and 40μm. The curvature radius of the second adaptation arc zone can be changed so that the end of the second adaptation arc zone forms an edge warp at a predetermined distance (such as 5μm to 40μm) from the cornea, or the second adaptation arc zone can be designed as an aspherical surface so that the end of the second adaptation arc zone forms an edge warp at a predetermined distance from the cornea. Optionally, these two methods can be used simultaneously to make the end of the second adaptation arc zone form an edge warp at a predetermined distance from the cornea.

[0112] When the curvature radius of AC2 is changed and / or AC2 is set as an aspherical surface so that the end of the second fitting arc zone forms an edge warping at a predetermined distance from the cornea, the curvature radius and / or eccentricity of AC2 can be calculated based on the value of the predetermined distance.

[0113] According to clinical data, when the orthokeratology lens is improved in the above manner so that the tear layer thickness at the end of the second fitting arc zone is increased by 5μm to 40μm, fluorescent staining can be used to observe that the second fitting arc zone has a thinner sublens tear layer. During the 12-month observation period, the patients had good wearing comfort and the lens fitting was not changed due to the design improvement.

[0114] Based on the above design principle, the present invention also conducted clinical trials to verify the effectiveness of the above design. The results show that by improving the central tear layer and the peripheral tear layer, the safety of orthokeratology lenses can be effectively improved, and the occurrence of device-related adverse events can be reduced by 34%, which breaks the old-generation orthokeratology lens's cognition about the tear layer.

[0115] In summary, increasing the tear thickness in the central and peripheral areas by the method described above can effectively improve the safety of orthokeratology lenses without sacrificing the shaping efficiency of orthokeratology lenses.

[0116] Figure 5 A simplified cross-sectional view of a corneal reshaping lens according to another embodiment of the present disclosure is shown.

[0117] See also Figure 5, AC1 represents the first adaptation arc area, and AC2 represents the second adaptation arc area. The curvature radius of AC2 can be set to be greater than the curvature radius of AC1, and the curvature radius of AC2 is 0.05mm to 1.15mm greater than the curvature radius of AC1. In this way, the end of the second adaptation arc area can form an edge warping between 5μm and 40μm.

[0118] Figure 6 A simplified cross-sectional view of a corneal reshaping lens according to another embodiment of the present disclosure is shown.

[0119] See also Figure 6 , AC2 can be set as an aspherical surface, and the eccentricity range is +0.2 to +0.9. In this way, the end of the second adaptive arc area can also form an edge warping between 5 μm and 40 μm.

[0120] The present disclosure relates to detailed optimization of the lens and even the subocular tears, which can improve the subocular tear state of the central shaping area and the peripheral fitting area, make the subocular tear layer distributed and full, and the exchange is sufficient and gentle, thereby making the safety of lens wearing better.

[0121] Figure 7 A comparison chart of the fluorescent staining of the orthokeratology lens of the present invention and the conventional orthokeratology lens is shown.

[0122] Figure 7 The left side in the middle is a tear fluorescence staining image of the orthokeratology lens disclosed in the present invention. Figure 7 The middle right side shows the fluorescence staining of tears for conventional orthokeratology lenses. Figure 7 As shown in the left view, in the adaptation arc area (area C), the first adaptation arc area (the part within the red circle) shows a darker color, indicating that there is less tear layer in this area; the second adaptation arc area (the part outside the red circle) shows a slightly brighter green, which indicates that there is slightly more tear layer in this area.

[0123] contrast Figure 7 It can be seen from the left and right views that the tears under the lens after the optimized design have the characteristics of a smooth transition, and there is no obvious boundary between the areas. In addition, the clinical trial results show that the orthokeratology lens disclosed in the present invention optimizes the distribution and exchange of tears, and significantly reduces the incidence of common clinical adverse reactions, such as corneal staining, conjunctivitis, keratitis, corneal abrasions, corneal damage, etc. The incidence rate is reduced by 26% to 63%, indicating that the present disclosure has a significant effect on improving the safety of orthokeratology lenses.

[0124] The orthokeratology lens according to the present disclosure has been described above in detail with reference to the accompanying drawings.

[0125] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A corneal reshaping lens having a rear surface for shaping the front surface of the cornea, wherein the rear surface has a base curve area and a reverse curve area, characterized in that: The radius of curvature of the base curve area gradually decreases from the center to the periphery; and / or The curvature radius of the reverse arc region is smaller than the curvature radius of the base arc region, and gradually decreases from the inside to the outside; and / or A region of a predetermined width at the end of the base arc region is set as a transition arc region, and a curvature radius of the transition arc region is smaller than a curvature radius of the base arc region and larger than a curvature radius of the reversal arc region.

2. The orthokeratology lens according to claim 1, characterized in that: The back surface parameters of the orthokeratology lens are configured so that the thickness of the tear layer after the shaping process is stabilized is within a first interval range, and the first interval range is a numerical range determined so that the surface free energy of the tear layer is not less than a first value and the cohesive force is not less than a second value. The back surface parameters include at least one of the aspheric characteristic parameter value of the base curve zone, the aspheric characteristic parameter value of the reversal arc zone, and the width and curvature radius of the transition arc zone.

3. The orthokeratology lens according to claim 1, characterized in that: The aspheric characteristic parameter value of the base curve region is configured to increase the base curve region sagittal height by a third value.

4. The orthokeratology lens according to claim 3, characterized in that: The eccentricity of the base arc region ranges from -0.45 to -1.

25.

5. The orthokeratology lens according to claim 1, characterized in that: The aspheric characteristic parameter value of the reverse arc area is configured to increase the tear layer thickness by a third value.

6. The orthokeratology lens according to claim 4, characterized in that: The eccentricity of the reversal arc region ranges from -0.20 to -0.

60.

7. The orthokeratology lens according to claim 1, characterized in that: The width and the radius of curvature of the transition arc zone are configured to increase the thickness of the tear layer by a third value.

8. The orthokeratology lens according to claim 7, characterized in that: The width of the transition arc zone is between 0.1 mm and 0.3 mm. The difference between the curvature radius of the base arc zone and the curvature radius of the transition arc zone is between 0.35 mm and 3.00 mm.

9. The orthokeratology lens according to any one of claims 3 to 8, characterized in that: The third value is 7 μm to 10 μm.

10. The orthokeratology lens according to claim 1, characterized in that , The rear surface also has an adapting arc area and a peripheral arc area, The adaptation arc area includes a first adaptation arc area and a second adaptation arc area, The first adaptation arc zone is connected to the reversal arc zone, and the second adaptation arc zone is connected to the peripheral arc zone. The first adaptation arc area is parallel to the corresponding area of ​​the cornea, and the second adaptation arc area gradually moves away from the cornea from the inside to the outside.

11. The orthokeratology lens according to claim 10, characterized in that , The distance between the end of the second adaptation arc zone and the cornea is between 5 μm and 40 μm.

12. The orthokeratology lens according to claim 11, characterized in that , The curvature radius of the second adaptation arc area is 0.05 mm to 1.15 mm greater than the curvature radius of the first adaptation arc area; and / or The eccentricity of the second adaptation arc region ranges from +0.20 to +0.90.

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