Bifocal presbyopic orthokeratology lens based on regional refraction

Abstract

The invention relates to the technical field of orthokeratology lenses, and discloses a bifocal presbyopic orthokeratology lens based on regional refraction. A base arc area, a reversal arc area, a positioning arc area and a peripheral arc area which are connected with one another are sequentially arranged on the inner surface of the bifocal presbyopic orthokeratology lens from the center to the periphery, the base arc area comprises a low-beam light area, a high-beam light area and a transition area, the low-beam light area is located on the first half side of the base arc area, and the high-beam light area is located on the second half side of the base arc area. The transition area is located between the low-beam light area and the high-beam light area, and the curvature of the low-beam light area, the curvature of the transition area and the curvature of the high-beam light area are sequentially decreased. According to the embodiment of the invention, the comfort, convenience and safety in the presbyopia correction process can be improved.

Description

Technical Field

[0001] This application relates to the field of orthokeratology lens technology, and in particular to a bifocal presbyopic orthokeratology lens based on regional refraction. Background Technology

[0002] Presbyopia is a physiological phenomenon that inevitably occurs as people enter middle and old age. The core cause is that with age, the density of the lens increases and its elasticity decreases, and the ciliary muscle's ability to contract weakens, leading to an absolute decline in the eye's accommodation ability. This manifests as difficulty seeing near objects, requiring the use of convex lenses to obtain clear near vision.

[0003] Currently, the mainstream clinical methods for correcting presbyopia include bifocal lenses, progressive multifocal lenses, multifocal contact lenses, and surgical correction. Among them, while bifocal lenses can meet the needs of both near and far vision simultaneously, they have a noticeable "image jump" phenomenon and a visual boundary line, which affects visual comfort and easily reveals age. Progressive multifocal lenses solve the image jump problem, but they have drawbacks such as peripheral aberrations, a long adaptation period, and rely on precise fitting. Multifocal contact lenses need to be worn for a long time during the day, which poses risks of insufficient oxygen permeability and eye infection. Surgical correction has problems such as trauma, postoperative complications, and limited indications, making it difficult to meet the convenience and non-invasive needs of most middle-aged and elderly patients. Summary of the Invention

[0004] The purpose of this application is to provide a bifocal presbyopic corneal reshaping lens based on regional refraction, which aims to improve the comfort, convenience and safety of the presbyopia correction process.

[0005] This application provides a bifocal presbyopic orthokeratology lens based on regional refraction. The inner surface of the bifocal presbyopic orthokeratology lens based on regional refraction is provided with interconnected base arc region, reversal arc region, positioning arc region and peripheral arc region from the center to the outer periphery. The base arc region includes near light region, distance light region and transition region. The near light region is located on the first half of the base arc region, the distance light region is located on the second half of the base arc region, and the transition region is located between the near light region and the distance light region. The curvature of the near light region, the transition region and the distance light region decreases sequentially.

[0006] In some embodiments, the curvature of the transition zone gradually changes from the near-field light region to the far-field light region.

[0007] In some embodiments, the light energy allocation ratio of the near-field light zone is (35%, 40%), the light energy allocation ratio of the far-field light zone is (55%, 60%), and the light energy allocation ratio of the transition zone is (0%, 5%).

[0008] In some embodiments, the radii of curvature of the near-field light region and the far-field light region satisfy the following relationship: , in, Additional luminosity is applied to the target area. The refractive index of tears, The refractive index of air, The radius of curvature of the near-light-use region. The radius of curvature of the far-field optical region.

[0009] In some embodiments, the target near-field additional photometric value is [+1.00D, +3.00D], which is positively correlated with the target age parameter.

[0010] In some embodiments, the sagittal height of the inverted arc region is the difference between the sagittal height of the target cornea and the sagittal height of the base arc region.

[0011] In some embodiments, the formula for calculating the radius of curvature of the inverted arc region is: , in, The radius of curvature of the inverted arc region. The sag of the inverted arc region, The width of the reverse arc, It is the diameter of the optical zone on the outer surface of the orthokeratology lens.

[0012] In some embodiments, the positioning arc region is an aspherical shape, and the positioning arc region is provided with a first positioning arc region and a second positioning arc region connected to each other in sequence from one end near the reverse arc region outward. The curvature of the first positioning arc region is greater than the curvature of the second positioning arc region.

[0013] In some embodiments, the formulas for calculating the curvature of the first positioning arc region and the second positioning arc region are as follows: , , in, The curvature of the first positioning arc region. The curvature of the second positioning arc region. The flattest curvature of the target cornea, The eccentricity of the target cornea. It is a constant.

[0014] In some embodiments, the bifocal presbyopic orthokeratology lens has a refractive index of 1.336±0.1 and an oxygen permeability coefficient of DK125.

[0015] The beneficial effects of this application are as follows: By dividing the base curve region into a near-vision zone, a distance-vision zone, and a transition zone with smooth curvature transitions, the curvature of the near-vision zone, the distance-vision zone, and the transition zone decreases sequentially. Combined with the synergistic effect of the reversal curve zone, the positioning curve zone, and the peripheral curve zone, effective corneal reshaping is achieved for presbyopic patients. A bifocal optical surface with a smooth transition can be directly formed on the cornea, effectively avoiding "image jump" and visual demarcation lines, and improving the user's visual comfort and naturalness. At the same time, since this corneal reshaping lens is worn at night, users do not need to wear any lenses during the day, thus fundamentally eliminating the risk of insufficient oxygen permeability and eye infection that may be caused by wearing contact lenses during the day, improving convenience and safety. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the inner surface structure of a bifocal presbyopic corneal reshaping lens based on regional refraction provided in an embodiment of this application.

[0017] Figure 2 This is a schematic diagram of the cross-sectional structure of the bifocal presbyopic corneal reshaping lens based on regional refraction provided in the embodiments of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] It should be noted that the terms "first," "second," "third," "fourth," etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a system, product, or device that includes a series of circuits is not necessarily limited to those explicitly listed, but may include other circuits not explicitly listed or inherent to such systems, products, or devices.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0021] In traditional presbyopia correction techniques, bifocal lenses cause image jump due to the presence of optical demarcation lines, leading to interruptions in visual continuity. While progressive multifocal lenses eliminate image jump, peripheral aberrations remain, and the adaptation period is lengthy. Multifocal contact lenses increase the risk of eye infections due to insufficient oxygen permeability and prolonged wear. Surgical correction carries the risk of postoperative complications due to invasive procedures. These shortcomings collectively make it difficult for existing technologies to simultaneously meet the requirements of non-invasiveness, convenience, and visual comfort. Furthermore, interruptions in visual continuity and peripheral aberrations have been observed to directly affect the dynamic visual quality of users in daily activities, while insufficient oxygen permeability and the risk of postoperative complications are linked to a decline in the reliability of eye health maintenance. For example, in an educational setting, a 55-year-old teacher wearing progressive multifocal lenses during classroom teaching experiences peripheral aberrations causing visual blurring when shifting their gaze from the blackboard to the students. This necessitates adjusting their head angle to obtain a clear view, disrupting the flow of instruction and exacerbating eye fatigue. Furthermore, visual discomfort experienced during the adaptation period was recorded as a key factor reducing daily use compliance. Frequent head adjustments not only affect teaching efficiency but also cause persistent discomfort during visual focus switching.

[0022] If the above problems are not addressed, it will lead to a decrease in user acceptance of existing correction methods, an increase in the potential risk of visual function deterioration, and a depletion of medical resources due to the replacement or adjustment of correction devices, ultimately affecting the effectiveness of visual health maintenance for middle-aged and elderly people. Among these issues, the persistent presence of visual continuity interruption and peripheral aberrations is analyzed as potentially accelerating users' abandonment of correction behavior, thereby further limiting their daily activities and reducing their quality of life.

[0023] Based on this, this application provides a bifocal presbyopic corneal reshaping lens based on regional refraction. By dividing the base curve area into a near vision zone, a distance vision zone, and a transition zone with smooth curvature transition, it achieves a smooth transition between near and distance vision, reduces visual interruption and discomfort, and improves wearing comfort and safety.

[0024] See also Figure 1 and Figure 2 In one embodiment, the inner surface of the bifocal presbyopic corneal reshaping lens based on regional refraction is provided with interconnected base arc region 1, reversal arc region 2, positioning arc region 3 and peripheral arc region 4 from the center to the outer periphery. The base arc region 1 includes near light region 11, far light region 12 and transition region 13. Near light region 11 is located on the first half of the base arc region 1, far light region 12 is located on the second half of the base arc region 1, and transition region 13 is located between near light region 11 and far light region 12. The curvature of the near light region 11, transition region 13 and far light region 12 decreases sequentially.

[0025] The inner surface of a bifocal orthokeratology lens for presbyopia refers to the side of the lens that directly contacts the cornea. This surface is the core structure that enables corneal reshaping and optical correction.

[0026] The base curve zone 1 refers to the central area of ​​the inner surface of the orthokeratology lens, directly covering the central optical zone of the cornea. The design of this area plays a decisive role in the corneal reshaping effect and the final vision correction. The near vision zone 11 refers to the area within the base curve zone 1 used to provide near vision correction. By reshaping the corresponding area of ​​the cornea, light is focused onto the retina in this area, thus achieving clear near vision. The distance vision zone 12 refers to the area within the base curve zone 1 used to provide distance vision correction. By reshaping the corresponding area of ​​the cornea, light is focused onto the retina in this area, thus achieving clear distance vision. The transition zone 13 refers to the area within the base curve zone 1 that connects the near vision zone 11 and the distance vision zone 12. The design of this area aims to achieve a smooth transition of curvature between different optical zones, avoiding visual discomfort such as "image jump."

[0027] The reverse curve zone 2 refers to the area located outside the base curve zone 1. Its curvature is usually flatter than that of the base curve zone 1, and it is used to form a tear reservoir between the lens and the cornea. This tear reservoir plays an important hydraulic role in the corneal reshaping process, assisting in the change of corneal shape.

[0028] Positioning arc zone 3, located outside the reversal arc zone 2, primarily functions to help the lens maintain a stable, centered position on the ocular surface, ensuring the accuracy and repeatability of the shaping effect. The design of this area helps reduce lens slippage on the eyeball.

[0029] The peripheral arc zone 4 refers to the outermost area on the inner surface of the orthokeratology lens. It is used to ensure a good transition between the lens edge and the cornea, reduce edge lifting or pressure, and improve wearing comfort.

[0030] The inner surface structure of this bifocal presbyopic orthokeratology lens based on regional refraction is designed with interconnected base arc region 1, reversal arc region 2, positioning arc region 3, and peripheral arc region 4 arranged sequentially from the center outwards. In one implementation, these regions can be designed in a segmented manner, with each region having independent geometric parameters and connected by precise connection points. In another implementation, a continuous mathematical function can be used to describe the entire inner surface, ensuring a smooth transition between the regions.

[0031] The base arc region 1 is designed to include a near-field beam region 11, a far-field beam region 12, and a transition region 13. The near-field beam region 11 is located on the first half of the base arc region 1, the far-field beam region 12 is located on the second half of the base arc region 1, and the transition region 13 is located between the near-field beam region 11 and the far-field beam region 12. The near-field beam region 11 and the far-field beam region 12 can be designed as concentric fan-shaped regions, centered on the center of the base arc region 1, and distributed on the first and second halves of the base arc region 1, respectively. The curvature of the near-field beam region 11, the transition region 13, and the far-field beam region 12 is designed to decrease sequentially, and a piecewise linearly decreasing curvature design can be adopted, that is, the curvature of each region changes linearly in the radial direction.

[0032] Compared to traditional bifocal lenses, this solution effectively avoids the "image jump" phenomenon and visual demarcation line inherent in bifocal lenses by directly forming a bifocal optical surface with a smooth transition on the cornea, thus significantly improving the user's visual comfort and naturalness. For example, when switching from reading to viewing distant objects, the user's visual experience is continuous and uninterrupted, which is difficult to achieve with traditional bifocal lenses. Compared to progressive multifocal lenses, this embodiment avoids the peripheral aberration problems that may exist with progressive multifocal lenses by reshaping the eye at night and allowing naked-eye vision during the day. Furthermore, since the user does not need to wear lenses during the day, the adaptation period is reduced, allowing the user to adapt to the new visual pattern more quickly. In addition, compared to multifocal contact lenses worn long-term during the day, the nighttime wearing mode of this orthokeratology lens eliminates the need for the user to wear any lenses during the day, fundamentally eliminating the risk of insufficient oxygen permeability and eye infection that may result from wearing contact lenses during the day. The user's eye health and comfort are better guaranteed. Furthermore, as a non-invasive and reversible physical correction method, this approach avoids the trauma, postoperative complications, and limited indications associated with surgical correction. Users can achieve effective vision correction without the risks of surgery, meeting the urgent needs of middle-aged and elderly patients for convenient and non-invasive correction methods.

[0033] In summary, this embodiment, through its ingenious design of the inner surface area, particularly the rational layout and sequentially decreasing curvature of the near vision zone 11, the far vision zone 12, and the transition zone 13 within the base arc zone 1, combined with the synergistic effect of the reversal arc zone 2, the positioning arc zone 3, and the peripheral arc zone 4, achieves effective corneal reshaping. This provides presbyopic patients with a safe, effective, comfortable, and convenient bifocal vision correction solution, significantly improving their quality of life.

[0034] In some embodiments, the curvature of the transition region 13 gradually changes from the near-lighting region 11 to the far-lighting region 12.

[0035] The curvature of the transition region 13 gradually changes from the near-field light-emitting region 11 to the far-field light-emitting region 12. This can be achieved by precisely controlling the geometry of the transition region 13 surface during manufacturing using CNC turning or molding techniques. The curvature can be made to gradually decrease from the edge of the near-field light-emitting region 11 along a preset mathematical function (e.g., linear, parabolic, or higher-order curve) until the edge of the far-field light-emitting region 12. Alternatively, a refractive index gradient can be formed within the transition region 13 using variable refractive index materials or layered material techniques, thereby optically simulating the gradual curvature effect and allowing light to focus smoothly when passing through this region.

[0036] The solution in this application designs the curvature of the transition zone 13 to gradually change from the near vision zone 11 to the far vision zone 12, resulting in a smoother optical transition between different visual zones on the inner surface of the orthokeratology lens. In the base curve region 1, the curvatures of the near vision zone 11, transition zone 13, and far vision zone 12 decrease sequentially. This gradual design ensures that the change in refractive power from the high-curvature near vision zone 11 to the low-curvature far vision zone 12 is continuous and without abrupt changes. When the wearer's gaze shifts from a near target to a far target, light passes through the gradually changing curvature of the transition zone 13, avoiding visual blurring or aberrations caused by sudden changes in refractive power, thus providing a more comfortable and natural visual experience. This smooth curvature transition helps optimize the distribution of the tear film on the lens surface, further improving wearing comfort and reducing visual interference caused by optical discontinuities.

[0037] As a specific implementation, the curvature of the transition zone 13 can be designed to gradually decrease from the edge of the near-vision zone 11 using a preset nonlinear function (e.g., a cubic Bézier curve or an exponential function) until it smoothly connects with the curvature of the edge of the far-vision zone 12. During manufacturing, a high-precision CNC lathe can be used to machine the inner surface of the lens. By programming and controlling the tool path and angle, the transition zone 13 with its gradual curvature can be precisely sculpted. For example, the curvature change per 0.1 mm radial distance within the transition zone 13 can be set to ensure that the overall curvature change is continuous and controllable. Furthermore, the lens design software can simulate the effects of different gradient functions on optical performance, selecting the optimal gradient curve to achieve ideal visual effects and wearing comfort.

[0038] Through the aforementioned technical solution, the curvature of the transition zone 13 gradually changes from the near vision zone 11 to the distance vision zone 12, effectively solving the visual discomfort and aberration problems that may occur when switching between different viewing distances. This smooth curvature transition allows the wearer to obtain a more continuous and natural visual experience when switching between near and distance vision, significantly improving the wearing comfort and visual quality of bifocal presbyopic orthokeratology lenses. At the same time, the gradual curvature design also helps to ensure the uniform distribution of the tear film on the lens surface, further optimizing the physiological adaptability of the lens.

[0039] In some embodiments, the light energy allocation ratio of the near-field light zone 11 is (35%, 40%), the light energy allocation ratio of the far-field light zone 12 is (55%, 60%), and the light energy allocation ratio of the transition zone 13 is (0%, 5%).

[0040] This application's solution precisely controls the light energy distribution ratio of the near vision zone 11, the distance vision zone 12, and the transition zone 13 of a bifocal presbyopic corneal reshaping lens based on regional refraction. This allows incident light to be focused at near and far distances according to preset ratios, thereby forming clear near and far images on the patient's retina. The near vision zone 11 and the distance vision zone 12 respectively undertake the main myopia and hyperopia correction functions. Their light energy distribution ratios are optimized based on human eye visual physiology and the actual visual needs of presbyopic patients, ensuring sufficient brightness perception and image clarity at different viewing distances. Simultaneously, the extremely low light energy distribution ratio of the transition zone 13 effectively avoids interference with overall visual quality, ensuring a smooth visual transition and reducing visual discomfort such as glare and halos. This precise light energy distribution mechanism allows the corneal reshaping lens to work collaboratively as a whole system, providing presbyopic patients with a stable and comfortable bifocal visual experience and significantly improving the correction effect.

[0041] As a specific implementation, a bifocal presbyopic orthokeratology lens based on regional refraction can be designed such that its near vision zone 11 is configured on the lower side (first half) of the base curve zone 1 and optimized to achieve a light energy distribution ratio of 39%. The distance vision zone 12 is configured on the upper side (second half) of the base curve zone 1, designed to achieve a light energy distribution ratio of 57%. A transition zone 13, located between the near vision zone 11 and the distance vision zone 12, has its optical design finely adjusted to ensure a light energy distribution ratio of only 4%. This light energy distribution can be achieved using advanced computer-aided design (CAD) and optical simulation software, iteratively adjusting the diameter, radius of curvature, aspheric coefficient, and surface microstructure of each zone until the target light energy distribution ratio is achieved. For example, a steeper aspheric design in the near vision zone 11 can increase its light energy focusing ability, while a relatively flat aspheric design in the distance vision zone 12 can maintain distance vision. Transition zone 13 can employ a gradual curvature change to minimize light scattering and aberrations.

[0042] Through the aforementioned technical solution, the bifocal presbyopic orthokeratology lens based on regional refraction can achieve precise control and optimized distribution of incident light energy. This precise light energy distribution mechanism allows patients to simultaneously obtain clear near and far vision while wearing the lens, effectively solving the problem of blurred vision at different distances for presbyopic patients. Compared with designs without optimized light energy distribution, the solution presented in this application significantly improves visual comfort and reduces visual interference such as glare and halos caused by uneven light distribution, thus providing presbyopic patients with a more stable, clear, and comfortable visual experience.

[0043] In some embodiments, the radii of curvature of the near-field light region 11 and the far-field light region 12 satisfy the following relationship: , in, Additional luminosity is applied to the target area. The refractive index of tears, The refractive index of air, The radius of curvature of the near-light-use region 11, The radius of curvature of the far-field optical region 12 is given.

[0044] This application's solution introduces a precise mathematical formula that directly links the radii of curvature of the near vision zone 11 and the distance vision zone 12 of a bifocal presbyopic orthokeratology lens to the target near vision supplementary power. This formula considers the optical interface formed between the tear film and the cornea, calculating the actual target near vision supplementary power by combining the difference between the tear film refractive index and the air refractive index with the radii of curvature of the near vision zone 11 and the distance vision zone 12. This design allows for precise determination or adjustment of the radii of curvature of the near vision zone 11 and the distance vision zone 12, given the target near vision supplementary power, thereby ensuring the lens provides the expected near vision correction. In this way, the near vision zone 11, the distance vision zone 12, and the transition zone 13 in the base curve region 1 of the lens's inner surface work together to provide stable and accurate near vision supplementary power while maintaining distance vision correction, effectively solving the problem of precise control of supplementary power in traditional designs.

[0045] The following is a specific example. As a concrete implementation, when a target near-vision supplemental power of +2.00D is required to provide a patient, the tear refractive index can be set to 1.336 and the air refractive index to 1. In this case, by adjusting the radius of curvature of the near-vision zone 11 and the radius of curvature of the distance-vision zone 12, the target near-vision supplemental power and the radii of curvature of both the near-vision zone 11 and the distance-vision zone 12 can satisfy the aforementioned relationship. For example, the radius of curvature of the near-vision zone 11 can be determined first, and then the radius of curvature of the distance-vision zone 12 can be derived from the formula, or vice versa. This method ensures that after the lens is worn, the interaction between the tear film and the cornea precisely generates the required power difference between the near-vision zone 11 and the distance-vision zone 12, thereby achieving the desired presbyopia correction effect.

[0046] Through the aforementioned technical solution, the radii of curvature of both the near-vision zone 11 and the far-vision zone 12 are linked to the target near-vision supplemental power via a precise mathematical formula, taking into account the influence of the tear film layer. This makes the design process of bifocal presbyopic orthokeratology lenses more scientific and precise. This significantly improves the predictability and stability of the lens's optical performance, avoiding errors caused by empirical design or estimation, thereby providing patients with more accurate and comfortable near-vision supplemental power correction. This precise design method helps optimize the overall optical performance of the lens, improving the patient's visual quality and wearing experience.

[0047] In some embodiments, the target near-field additional photometric value is [+1.00D, +3.00D], which is positively correlated with the target age parameter.

[0048] The target near-vision supplemental power can be set based on the patient's initial presbyopia level or expected correction effect. For example, for patients with early-stage presbyopia, a lower supplemental power value, such as +1.00D to +1.50D, can be selected; while for patients with moderate to severe presbyopia, a higher supplemental power value, such as +2.00D to +3.00D, may be required. Furthermore, this range provides a clear boundary for subsequent lens customization. A positive correlation with the target age parameter clarifies the relationship between the target near-vision supplemental power and the target age parameter. The target age parameter refers to the patient's actual age or physiological age, which is closely related to the progression of presbyopia. This correlation can be achieved through a pre-defined age-supplemental power table, for example, increasing the supplemental power by 0.25D for every 5 years of age. Alternatively, a mathematical model can be established, using age as an input variable to calculate the corresponding target near-vision supplemental power. This design considers the physiological characteristic of presbyopia worsening with age, allowing lens design to better adapt to the individualized needs of patients.

[0049] The design of the target near-vision supplemental power can be systematically determined before lens manufacturing based on the patient's actual or physiological age. For example, for patients of different age groups, a suitable value can be selected from a preset supplemental power range based on their age parameters. Once the target near-vision supplemental power is determined, it can be substituted into the aforementioned radius of curvature calculation formula to accurately calculate the required radii of curvature for both near-vision zone 11 and distance-vision zone 12. This method ensures that the lens's optical design matches the patient's degree of presbyopia; as age increases, the required supplemental power also increases accordingly, thus guaranteeing the continuity and effectiveness of the corrective effect. In this way, the lens design is no longer single and fixed but can be dynamically adjusted according to the patient's age characteristics, achieving a highly personalized presbyopia correction plan.

[0050] The following example illustrates this. Suppose a patient is 50 years old. Based on their target age parameter, their required target near-vision supplemental power can be determined. For instance, according to a pre-defined age-supplemental power correspondence, a 50-year-old patient might require a target near-vision supplemental power of +1.75D, which falls within the range of +1.00D to +3.00D. Once the target near-vision supplemental power of +1.75D is determined, it can be substituted into the formula relating the radii of curvature of near-vision zone 11 and distance-vision zone 12, combined with the known values ​​of tear refractive index and air refractive index, to accurately calculate the required radii of curvature for near-vision zone 11 and distance-vision zone 12. As another example, for a 60-year-old patient, due to their higher target age parameter, their required target near-vision supplemental power might be +2.50D, also within the aforementioned range. In this way, orthokeratology lenses with corresponding near-vision supplemental powers can be customized for patients of different ages to meet their individual vision correction needs.

[0051] In one specific embodiment, the formula for calculating the target proximity additional luminosity is: , , in, To adjust the amplitude, The target age parameter.

[0052] Through the above technical solution, this application solves the problem of how to accurately determine and adjust the target near-vision supplementary power according to individual differences in the design of bifocal presbyopia orthokeratology lenses based on regional refraction. By limiting the target near-vision supplementary power to the range of [+1.00D, +3.00D] and making it positively correlated with the target age parameter, the lens design can fully consider the physiological characteristics of presbyopia that change with age. This not only provides clear and operational guidance for the optical design of the lens, but also ensures that the designed orthokeratology lens can provide personalized near-vision supplementary power that matches the patient's age. Therefore, this solution significantly improves the accuracy and adaptability of bifocal presbyopia orthokeratology lenses in presbyopia correction, thereby providing patients with better visual correction effects and a more comfortable wearing experience.

[0053] In some embodiments, the sagittal height of the inverted arc region 2 is the difference between the sagittal height of the target cornea and the sagittal height of the base arc region 1.

[0054] The sagitta of the reversal arc zone 2 refers to the vertical distance from the midpoint of the arc to the chord. Its precise design is crucial for ensuring stable positioning of the lens on the cornea, forming an appropriate tear film layer, and achieving the desired corneal reshaping effect. This sagitta can be calculated iteratively using computer-aided design (CAD) software based on corneal topography data and preset reshaping targets, or it can be derived by establishing a mathematical model that correlates the parameters of each region of the orthokeratology lens with the geometric features of the cornea.

[0055] Target corneal sagitta refers to the corneal sagitta in the region where the lens is expected to achieve a specific shaping effect when designing orthokeratology lenses. It reflects the original shape of the cornea or the target shape after shaping. Target corneal sagitta can be determined by measuring the patient's corneal data with a corneal topography instrument and combining it with clinical experience or a pre-set shaping target. Alternatively, it can be predicted by statistically analyzing a large amount of clinical data to establish a relationship model between corneal sagitta and parameters such as age and refractive error.

[0056] The sag of the base curve 1 refers to the sag of the base curve 1 of an orthokeratology lens on a specific diameter. It directly affects the fit between the lens and the central corneal region, thus influencing the shaping effect and wearing comfort. The sag of the base curve 1 can be calculated using geometric formulas by measuring the radius of curvature and diameter of the base curve 1 of the lens, or it can be directly measured using optical measurement equipment, such as a non-contact three-dimensional measuring instrument.

[0057] This application achieves precise control over the geometry of the reversal arc zone 2 by setting its sagittal height to the difference between the target corneal sagittal height and the base arc zone 1. In orthokeratology lens design, the base arc zone 1 is in direct contact with the central cornea, and its sagittal height determines the initial pressure or support the lens exerts on the cornea. The target corneal sagittal height represents the desired corneal shape after reshaping. As the transition zone 13 between the base arc zone 1 and the positioning arc zone 3, the sagittal design of the reversal arc zone 2 is crucial. It needs to provide sufficient space to accommodate the reshaped corneal tissue and guide tear exchange. By calculating the difference between the target corneal sagittal height and the base arc zone 1 sagittal height, the required sagittal height of the reversal arc zone 2 can be precisely determined, thereby ensuring that the reversal arc zone 2 can form an ideal tear pool with the cornea, avoiding excessive pressure on the cornea and ensuring stable positioning of the lens on the cornea. This design approach allows the geometric parameters of the reverse arc zone 2 to be customized according to the characteristics of the individual cornea and the expected shaping effect, thereby optimizing the fit between the lens and the cornea.

[0058] The following is a concrete example. When designing a bifocal presbyopic orthokeratology lens based on regional refraction, the patient's corneal data is first obtained using a corneal topography system. Combined with parameters such as the patient's refractive error and age, a desired "target corneal sagitta" is determined using specialized orthokeratology lens design software (e.g., CAD software based on finite element analysis). Simultaneously, the "sagitta of base curve zone 1" is calculated based on the preset radius of curvature and diameter of base curve zone 1. Subsequently, the design software, or a preset algorithm, subtracts the "sagitta of base curve zone 1" from the "target corneal sagitta," and the difference is set as the "sagitta of reverse curve zone 2." This calculation method ensures that reverse curve zone 2 can accurately adapt to changes in corneal morphology, providing accurate geometric parameters for subsequent lens manufacturing.

[0059] In a specific embodiment, the formula for calculating the sag of the inverted arc region 2 is: , , , in, The sag of the inverted arc region 2, For the target corneal sagittal, Let the sag of base arc region 1 be , The radius of curvature of the far-field optical region 12, The diameter of the optical zone on the outer surface of the orthokeratology lens. The width of the reverse arc, For the K value, For the shape factor of the target cornea, This is the amount of compensation for irregularities on the corneal surface.

[0060] By setting the sagittal height of the reverse arc zone 2 to the difference between the target corneal sagittal height and the sagittal height of the base arc zone 1, the geometry of the reverse arc zone 2 can be precisely controlled. This precise design allows the reverse arc zone 2 of the orthokeratology lens to highly match the individual corneal morphological changes, forming an ideal tear pool, thereby effectively avoiding excessive pressure or insufficient adhesion of the lens to the cornea. This not only significantly improves the stability and comfort of the lens during wear but also optimizes tear exchange, helping to maintain corneal health. In addition, the precise sagittal height design of the reverse arc zone 2 helps ensure that the lens can more effectively guide corneal reshaping, thereby achieving a more stable and predictable corrective effect. This solves the problem of the difficulty in accurately determining the parameters of the reverse arc zone 2 in traditional designs, improving the overall performance of bifocal presbyopic orthokeratology lenses.

[0061] In some embodiments, the formula for calculating the radius of curvature of the inverted arc region 2 is: , in, Let be the radius of curvature of the inverted arc region 2.

[0062] This application solves the aforementioned problem by providing a specific calculation formula to determine the radius of curvature of the reversal arc zone 2. This formula correlates the radius of curvature of the reversal arc zone 2 with its sagitta, variable, and the optical zone diameter of the outer surface of the orthokeratology lens. Precise control of these parameters ensures the geometric accuracy of the reversal arc zone 2. Specifically, the sagitta of the reversal arc zone 2 is determined based on the difference between the target corneal sagitta and the sagitta of the base arc zone 1. This allows the reversal arc zone 2 to form the desired transition with the base arc zone 1 and apply precise shaping force to the cornea. The optical zone diameter defines the range of the central optical area of ​​the lens, ensuring the effective area of ​​the shaping effect. The application of this formula allows the radius of curvature of the reversal arc zone 2 to be precisely calculated according to actual design requirements, thereby ensuring smooth connections between different areas of the inner surface of the lens and the overall geometric harmony. This precise geometric control is crucial for achieving stable wear of bifocal presbyopic orthokeratology lenses, effective corneal shaping, and ultimately, effective vision correction. In this way, the lens can better fit the cornea, ensuring wearing comfort while achieving precise changes in corneal shape, thus achieving the dual purpose of correcting near and far vision.

[0063] The above technical solution provides a method for accurately calculating the radius of curvature of the reverse curve zone 2, effectively solving the problem of ensuring the geometric accuracy of the reverse curve zone 2 in the design of bifocal presbyopic orthokeratology lenses to achieve good reshaping effects and wearing comfort. This calculation formula directly links the radius of curvature of the reverse curve zone 2 with key parameters such as sagittal height and optical zone diameter, allowing designers to accurately determine the geometric parameters of the reverse curve zone 2 based on the target corneal morphology and the expected reshaping effect. This not only improves the scientific rigor and accuracy of lens design, avoiding errors that may result from empirical design, but also ensures a smooth transition and functional coordination between the reverse curve zone 2, the base curve zone 1, and other areas. Ultimately, this precise geometric control helps optimize the lens-corneal fit, enhances the stability and predictability of the corneal reshaping effect, and thus provides wearers with a clearer and more comfortable near and far vision correction experience.

[0064] In some embodiments, the positioning arc area 3 is an aspherical shape. The positioning arc area 3 is provided with a first positioning arc area 31 and a second positioning arc area 32 connected to each other from one end near the reverse arc area 2 outward. The curvature of the first positioning arc area 31 is greater than the curvature of the second positioning arc area 32.

[0065] The solution of this application achieves precise control over the contact relationship between the orthokeratology lens and the cornea by designing the positioning arc area 3 as an aspherical shape and subdividing it into a first positioning arc area 31 and a second positioning arc area 32 with specific curvature relationships. The aspherical positioning arc area 3 can more closely conform to the natural aspherical contour of the cornea, thereby reducing uneven contact between the lens and the cornea, lowering local pressure points, and promoting the uniform distribution and exchange of tears under the lens. This optimized fit helps to improve the central positioning stability of the lens. Furthermore, by setting the first positioning arc area 31, which is close to the reversal arc area 2, to have a greater curvature (i.e., steeper), this area can provide stronger centripetal force, effectively guiding and fixing the lens in the central position of the cornea. Subsequently, the second positioning arc area 32, which extends outward and has a smaller curvature (i.e., flatter), can provide a smoother transition and a wider support area, ensuring the stability and comfort of the lens during ocular surface movements, while avoiding excessive pressure on the peripheral corneal area. This segmented design with decreasing curvature allows the lens to maintain good central positioning while better adapting to the peripheral shape of the cornea, thus providing a more stable and precise corrective effect for bifocal presbyopia orthokeratology lenses.

[0066] As a specific implementation, the positioning arc region 3 can be described by a continuous aspherical curve. This curve has a relatively large curvature in the section near the reversal arc region 2 (i.e., the first positioning arc region 31), and a relatively small curvature in the outer peripheral section away from the reversal arc region 2 (i.e., the second positioning arc region 32). For example, an ellipsoid or paraboloid with a specific eccentricity can be used as the overall shape of the positioning arc region 3, and by adjusting the aspherical parameters, the curvature of its inner region (the first positioning arc region 31) is significantly greater than that of its outer region (the second positioning arc region 32). These two regions are designed to be smoothly connected to ensure the continuity of the lens surface transition, avoid sharp edges or discontinuities, and thus improve wearing comfort.

[0067] Through the aforementioned technical solution, the positioning arc zone 3 of the bifocal presbyopic orthokeratology lens based on regional refraction can more accurately match the natural shape of the cornea, significantly improving the stability of the lens's central positioning and wearing comfort. This improved positioning accuracy helps ensure that the near vision zone 11 and the distance vision zone 12 are always in the optimal optical position, thereby providing a more stable and clearer correction effect for myopia and presbyopia, reducing visual fluctuations caused by lens displacement, and thus improving the patient's visual quality and satisfaction.

[0068] In some embodiments, the formula for calculating the curvature of both the first positioning arc region 31 and the second positioning arc region 32 is as follows: , , in, The curvature of the first positioning arc region 31, The curvature of the second positioning arc region 32, The flattest curvature of the target cornea, The eccentricity of the target cornea. It is a constant.

[0069] This application's solution precisely determines the curvature of both the first positioning arc zone 31 and the second positioning arc zone 32 by introducing a calculation formula based on the flattest curvature of the target cornea and the eccentricity of the target cornea. Specifically, the curvature of the first positioning arc zone 31 takes into account the individualized parameters (FK and e) of the patient's cornea, allowing the curvature of the first positioning arc zone 31 to be customized according to the patient's actual corneal morphology. Based on this, the curvature of the second positioning arc zone 32 is reduced by a constant from the curvature of the first positioning arc zone 31, ensuring that the curvature of the first positioning arc zone 31 is greater than that of the second positioning arc zone 32, thereby maintaining the aspherical shape characteristics of the positioning arc zone 3. This design allows the positioning arc zone 3 to achieve a closer match with the peripheral portion of the patient's aspherical cornea, thus providing a more stable centering effect when the lens is worn. Through this precise curvature calculation, the orthokeratology lens can better conform to the cornea, reducing lens slippage and misalignment, thereby optimizing the corneal reshaping effect and improving the stability and effectiveness of the treatment.

[0070] The following example illustrates this. When designing a bifocal presbyopic orthokeratology lens based on regional refraction, the first step is to obtain the patient's corneal parameters. For example, a corneal topography instrument can be used to perform detailed measurements of the patient's cornea, thereby obtaining the target corneal curvature and eccentricity. Assume a patient's FK is 42.00D (refractive power) and e is 0.5. The constant d can be set to 1 based on clinical experience. Based on clinical experience, the value is set to 0. Substituting these parameters into the calculation formula: AC1 = 42.00 + (-3.47 × 0.5^2 - 0.34 × 0.5 + 0.26) ≈ 41.22D. Then, the curvature AC2 of the second positioning arc zone 32 is calculated: AC2 = AC1 - d = 41.22 - 1 = 40.22D. Through the above calculations, the curvature of the first positioning arc zone 31 of the orthokeratology lens for this patient can be accurately determined to be 41.22D, and the curvature of the second positioning arc zone 32 can be determined to be 40.22D. These calculation results can then be input into the CNC machining equipment for orthokeratology lenses to manufacture lenses with precise aspherical positioning arc zones 3.

[0071] Through the aforementioned technical solution, the curvature of the first positioning arc zone 31 and the second positioning arc zone 32 is precisely calculated based on the individual corneal parameters of the patient, enabling the positioning arc zone 3 of the orthokeratology lens to better match the patient's aspheric corneal morphology. This precise matching helps improve the lens's centering stability on the ocular surface, reducing lens misalignment and slippage during wear, thereby ensuring the uniformity and predictability of the corneal reshaping effect. Furthermore, by introducing a constant, the curvature difference between the first positioning arc zone 31 and the second positioning arc zone 32 can be flexibly adjusted, further optimizing the lens-corneal fit, improving patient comfort, and ultimately increasing the success rate and clinical efficacy of bifocal presbyopia orthokeratology lenses.

[0072] In some embodiments, the bifocal presbyopic orthokeratology lens has a refractive index of 1.336±0.1 and an oxygen permeability coefficient of DK125.

[0073] This application's solution precisely controls the refractive index of the bifocal presbyopia orthokeratology lens within the range of 1.336±0.1, ensuring a stable optical interface between the lens and the tear film. This allows light to be accurately refracted according to a preset curvature change when passing through the near vision zone 11, the distance vision zone 12, and the transition zone 13, effectively correcting presbyopia and ensuring clear near and distance vision for the wearer. Simultaneously, the bifocal presbyopia orthokeratology lens has an oxygen permeability coefficient of DK125, indicating excellent oxygen permeability of the lens material. This high oxygen permeability ensures a continuous and sufficient oxygen supply to the cornea during sleep, effectively preventing complications such as corneal edema and infection caused by corneal hypoxia, thus protecting corneal physiological health and wearing safety. This material characteristic, combined with the refractive design of the lens's inner surface area, not only optimizes the optical correction effect but also significantly improves wearing comfort and safety, allowing the wearer to enjoy clear vision while fully protecting corneal health.

[0074] As a specific implementation, bifocal presbyopic orthokeratology lenses can be made of silicone hydrogel materials. For example, this material can be a copolymer containing hydroxyethyl methacrylate (HEMA), N-vinylpyrrolidone (NVP), and tris(trimethylsiloxy)silylpropyl methacrylate (TRIS). By precisely controlling the ratio of these monomers and the polymerization process, the refractive index of the final material can be stabilized at around 1.336, for example, 1.335 or 1.337. Simultaneously, by introducing monomers with high siloxane content and optimizing the amount of crosslinking agent, the oxygen permeability coefficient of the material can be ensured to reach or exceed DK125, for example, DK130 or DK140.

[0075] Through the aforementioned technical solutions, bifocal orthokeratology lenses for presbyopia have achieved significant optimization in material properties while providing regional refractive correction. Precisely controlled refractive index ensures accurate light refraction within the lens, maintaining the designed corrective effects of the near vision zone 11, the distance vision zone 12, and the transition zone 13, enabling wearers to achieve stable and clear near and distance vision. Furthermore, the high oxygen permeability greatly enhances wearing safety and comfort, effectively reducing the risk of corneal hypoxia and ensuring long-term corneal health, thereby significantly improving the wearing experience and visual quality for presbyopia patients.

[0076] In summary, the bifocal presbyopic corneal reshaping lens based on regional refraction provided in this application divides the base curve region into a near-vision zone, a distance-vision zone, and a transition zone with smooth curvature transitions. The curvature of the near-vision zone, the distance-vision zone, and the transition zone decreases sequentially. Combined with the synergistic effect of the reversal curve zone, the positioning curve zone, and the peripheral curve zone, it effectively reshapes the cornea of ​​presbyopic patients. It can directly form a bifocal optical surface with a smooth transition on the cornea, effectively avoiding "image jump" and visual demarcation lines, and improving the user's visual comfort and naturalness. At the same time, since this corneal reshaping lens is worn at night, the user does not need to wear any lenses during the day, thereby fundamentally eliminating the risk of insufficient oxygen permeability and eye infection that may be caused by wearing contact lenses during the day, improving convenience and safety.

[0077] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0078] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A bifocal presbyopia orthokeratology lens based on regional refraction, characterized in that, The inner surface of the bifocal presbyopic corneal reshaping lens based on regional refraction is provided with interconnected base arc region, reversal arc region, positioning arc region and peripheral arc region from the center to the outer periphery. The base arc region includes near light region, far light region and transition region. The near light region is located on the first half of the base arc region, the far light region is located on the second half of the base arc region, and the transition region is located between the near light region and the far light region. The curvature of the near light region, the transition region and the far light region decreases sequentially. The light energy distribution ratio of the near light region is (35%, 40%), the light energy distribution ratio of the far light region is (55%, 60%), and the light energy distribution ratio of the transition region is (0%, 5%).

2. The bifocal presbyopia orthokeratology lens based on regional refraction according to claim 1, characterized in that, The curvature of the transition zone gradually changes from the near-field light zone to the far-field light zone.

3. The bifocal presbyopia orthokeratology lens based on regional refraction according to claim 1, characterized in that, The radii of curvature of the near-field light region and the far-field light region satisfy the following relationship: ， in, Additional luminosity is applied to the target area. The refractive index of tears, The refractive index of air, The radius of curvature of the near-light-use region. The radius of curvature of the far-field optical region.

4. The bifocal presbyopia orthokeratology lens based on regional refraction according to claim 3, characterized in that, The target near-field additional photometric value is [+1.00D, +3.00D], which is positively correlated with the target age parameter.

5. The bifocal presbyopia orthokeratology lens based on regional refraction according to claim 1, characterized in that, The sagittal height of the inverted arc region is the difference between the sagittal height of the target cornea and the sagittal height of the base arc region.

6. The bifocal presbyopic corneal reshaping lens based on regional refraction according to claim 5, characterized in that, The formula for calculating the radius of curvature of the inverted arc region is: ， in, The radius of curvature of the inverted arc region. The sag of the inverted arc region, The width of the reverse arc, It is the diameter of the optical zone on the outer surface of the orthokeratology lens.

7. The bifocal presbyopic corneal reshaping lens based on regional refraction according to claim 1, characterized in that, The positioning arc area is an aspherical shape. The positioning arc area is provided with a first positioning arc area and a second positioning arc area connected to each other from one end near the reverse arc area to the outer periphery. The curvature of the first positioning arc area is greater than the curvature of the second positioning arc area.

8. The bifocal presbyopia orthokeratology lens based on regional refraction according to claim 7, characterized in that, The formulas for calculating the curvature of the first positioning arc region and the second positioning arc region are as follows: ， ， in, The curvature of the first positioning arc region, The curvature of the second positioning arc region. The flattest curvature of the target cornea, The eccentricity of the target cornea. It is a constant.

9. The bifocal presbyopic corneal reshaping lens based on regional refraction according to claim 1, characterized in that, The bifocal presbyopic corneal reshaping lens has a refractive index of 1.336±0.1 and an oxygen permeability coefficient of DK125.

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