Contact lens and design method thereof

Abstract

The present invention discloses a contact lens, which includes a marginal zone, which is smoothly connected to a transition zone and includes an inner surface of the marginal zone close to the surface of the eyeball and an outer surface of the marginal zone away from the surface of the eyeball. The position where the inner surface of the marginal zone and the outer surface of the marginal zone are smoothly connected forms the outer edge of the contact lens. When the marginal zone is cut, the inner surface contour curve and the outer surface contour curve of the marginal zone are both non-circular arcs, and the radial length d1 of the inner surface contour curve is greater than the radial length d2 of the outer surface contour curve of the marginal zone. The present application also relates to a design method for the contact lens as described above. The peripheral thickness of the contact lens described herein is thinner than that of the traditional design, and the thickness change rate is uniform, which is conducive to tear exchange.

Description

Technical Field

[0001] The present invention relates to the technical field of ophthalmic medical instruments, and in particular to a contact lens and a design method thereof. Background Art

[0002] To meet the requirements of contact lens wear, existing contact lenses, on the one hand, are designed to create a certain negative pressure between the lens and the user's eye when worn, allowing the lens to "stick" to the eyeball and prevent it from falling off. On the other hand, because contact lenses are worn for a long time, ensuring a certain degree of oxygen exchange during wear to ensure normal eye metabolism is crucial for maintaining eye health. Generally speaking, ensuring that the part of the eyeball beneath the lens (the cornea, or the cornea and sclera) receives sufficient oxygen is crucial for maintaining eye health. During daytime activities, the human eye's blinking response can promote a certain degree of oxygen-carrying tear exchange, but whether the lens design itself can better promote oxygen exchange is also crucial, so that the flow and exchange of oxygen-carrying tears can be maintained even when blinking less frequently and sleeping at night.

[0003] Existing contact lens designs typically feature rounded edges. While this design approach offers the advantage of ease of manufacture, it also creates a steep tear exchange path, resulting in poor tear exchange and wearer comfort. Long-term wear of these lenses for eye correction can lead to eye conditions such as dry eyes, caused by insufficient ocular cell metabolism.

[0004] Therefore, there is an urgent need to develop a contact lens and a design method thereof. Summary of the Invention

[0005] The purpose of the present application is first to provide a contact lens, thereby overcoming the defects in the above-mentioned prior art. Specifically, the contact lens provided by the present application also includes a marginal area, which is smoothly connected to the transition area and includes an inner surface of the marginal area close to the surface of the eyeball and an outer surface of the marginal area away from the surface of the eyeball. The position where the inner surface of the marginal area and the outer surface of the marginal area are smoothly connected forms the outer edge of the contact lens. When the marginal area is cut, the inner surface contour curve and the outer surface contour curve of the marginal area are both non-circular arcs, and the radial length d1 of the inner surface contour curve is greater than the radial length d2 of the outer surface contour curve of the marginal area. This design optimizes the overall design of the marginal area, improves wearing comfort, facilitates tear exchange, and protects eye health.

[0006] The present application also aims to provide a method for designing a contact lens as described above.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions.

[0008] In a first aspect, the present invention discloses a contact lens comprising:

[0009] an optical zone having the basic structure of the contact lens and having an optically corrective effect;

[0010] a landing zone, the landing zone providing positioning for the contact lens;

[0011] a transition zone connecting the optical zone and the landing zone and realizing auxiliary positioning and / or auxiliary optical correction when the contact lens is worn;

[0012] Wherein, the contact lens further comprises:

[0013] a peripheral region, the peripheral region having a structure smoothly or non-smoothly connected to the landing region, the peripheral region including an inner peripheral region surface close to the surface of the eyeball and an outer peripheral region surface away from the surface of the eyeball, and the position where the inner peripheral region surface and the outer peripheral region surface are connected forms the outer edge of the contact lens;

[0014] On the radial cross-section of the contact lens, the inner surface of the edge area defines an inner surface contour curve of the edge area, and the inner surface contour curve of the edge area extends a first distance between a first connection point P2 and an outer edge point P0; the outer surface of the edge area defines an outer surface contour curve of the edge area, and the outer surface contour curve of the edge area extends a second distance between a second connection point P4 and the outer edge point P0; the outer edge point P0 is formed at the intersection of the inner surface contour curve of the edge area and the outer surface contour curve of the edge area; the inner surface contour curve of the edge area and the outer surface contour curve of the edge area both have at least two different curvatures, and the radial length d1 of the inner surface contour curve is greater than the radial length d2 of the outer surface contour curve of the edge area.

[0015] Furthermore, the curvature of the outer surface contour curve monotonically increases along the second connection point P4 to the outer edge point P0, and the curvature of the inner surface contour curve monotonically decreases along the first connection point P2 to the outer edge point P0.

[0016] Furthermore, the outer surface contour curve of the edge region has a first fitting point P3, and the inner surface contour curve of the edge region has a second fitting point P1. The first fitting point P3 and the second fitting point P1 are located on an auxiliary line, and the auxiliary line is fitted by the outer edge point P0 on the outer edge portion and the eye sagittal point P5 corresponding to the outer edge point P0. The first fitting point P3 and the second fitting point P1 define a first distance P3P1. The second fitting point P1 and the outer edge point P0 define a second distance P1P0. The ratio of the second distance P1P0 to the first distance P3P1 ranges from 0.3 to 0.59.

[0017] Furthermore, a ratio of the second distance P1P0 to the first distance P3P1 ranges from 0.3 to 0.5.

[0018] Furthermore, a ratio of the second distance P1P0 to the first distance P3P1 ranges from 0.37 to 0.45.

[0019] Furthermore, the radial length d1 is preferably 0.10-0.8 mm, and d2 is preferably 0.05-0.6 mm.

[0020] Furthermore, the inner surface of the edge region has a first designed curved surface, and the equation of the first designed curved surface is as follows:

[0021] B post (t) = (1-t) 2 P2+2t(1-t)P1+t 2 P0,t∈[0,1];

[0022] The outer surface of the edge area has a second design curved surface, and the equation of the second design curved surface is as follows:

[0023] B ant (t) = (1-t) 2 P4+2t(1-t)P3+t 2 P0;

[0024] Where t is the fitting coefficient.

[0025] Furthermore, the contact lens is a scleral contact lens, a corneal contact lens or a corneoscleral contact lens.

[0026] Furthermore, a straight line P2P1 defined by the first connection point P2 of the inner surface of the edge area and the landing area and the second fitting point P1 is tangent to the contour curve of the inner surface of the edge area at the position of the first connection point P.

[0027] Furthermore, a straight line P4P3 defined by the outer surface of the edge area and the second connection point P4 of the landing area and the first fitting point P3 is tangent to the contour curve of the outer surface of the edge area at the position of the second connection point P4.

[0028] The present invention also discloses a contact lens design method, characterized in that the method comprises the following steps:

[0029] S10: determining the diameter of the contact lens, the outer edge point P0 of the contact lens, and the eye sagittal point P5 corresponding to the outer edge point P0 based on the wearer's ocular surface parameters;

[0030] S20: obtaining a plurality of fitting points corresponding to the inner surface of the edge area and the outer surface of the edge area respectively,

[0031] In a radial cross section of the contact lens,

[0032] The fitting points of the outer surface of the edge area are:

[0033] The first fitting point P3, the outer edge point P0 on the outer edge, and

[0034] A second connection point P4 between the outer surface of the edge area and the landing area;

[0035] The inner surface fitting points of the edge area are:

[0036] a second fitting point P1, an outer edge point P0 on the outer edge portion, and a first connection point P2 between the inner surface of the edge area and the landing area;

[0037] The edge region has a structure that is smoothly or non-smoothly connected to the landing region, the edge region includes an inner edge region surface close to the surface of the eyeball and an outer edge region surface away from the surface of the eyeball, and the position where the inner edge region surface and the outer edge region surface are connected forms the outer edge of the contact lens;

[0038] The first fitting point P3 and the second fitting point P1 are located on an auxiliary line;

[0039] The auxiliary line is determined by the outer edge point P0 on the outer edge portion and the eye sagittal point P5 corresponding to the outer edge point P0;

[0040] The first fitting point P3 and the second fitting point P1 define a first distance P3P1;

[0041] The second fitting point P1 and the outer edge point P0 define a second distance P1P0;

[0042] The second distance P1P0 and the first distance P3P1 have a ratio;

[0043] S30: Generating a first designed curved surface of the inner surface of the edge area and a second designed curved surface of the outer surface of the edge area by fitting the plurality of fitting points.

[0044] Furthermore, the ratio of the second distance P1P0 to the first distance P3P1 ranges from 0.3 to 0.59, preferably from 0.3 to 0.5, and more preferably from 0.37 to 0.45.

[0045] Furthermore, a ratio of the second distance P1P0 to the first distance P3P1 is selected so that a straight line defined by the first connection point P2 and the second fitting point P1 is tangent to the first design curved surface at the first connection point P2;

[0046] Furthermore, the ratio of the second distance P1P0 to the first distance P3P1 is selected so that a straight line defined by the second connection point P4 and the first fitting point P3 is tangent to the second designed curved surface at the second connection point P4.

[0047] Compared with the prior art, the positive effects of the present invention are as follows.

[0048] 1. The present invention first proposes a contact lens with a peripheral zone design that facilitates tear exchange. According to the present invention, the outer edge of the contact lens is positioned closer to the rear surface of the peripheral zone, so that the peripheral zone design ensures sufficient tear exchange while also providing comfortable wearing.

[0049] 2. The contact lens realized according to the present invention proposes for the first time a method of optimizing the inner surface curvature and outer surface area of the edge zone by utilizing the position of the outer edge point, which can obtain a more optimized edge zone design. This method is different from the prior art method of utilizing arcs for optimization. The peripheral thickness of the contact lens is thinner, and the thickness change rate is uniform, which is beneficial to tear exchange. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Shows a schematic diagram of a contact lens in the prior art. Figure 1 In the figure, area A refers to the optical zone, area B refers to the transition zone, area C refers to the landing zone, and area D refers to the edge zone.

[0051] Figure 2 Schematic diagram showing the outer edge design of a prior art contact lens.

[0052] Figure 3 The figure is a schematic diagram of the outer edge structure and identification of a contact lens according to an embodiment of the present invention.

[0053] Figure 4 The figure is a schematic diagram comparing a contact lens design structure executed according to the contact lens design method of the present invention and an arc-shaped structure of the prior art. DETAILED DESCRIPTION

[0054] Unless otherwise defined, technical or scientific terms used in this specification and claims shall have the same general meaning as understood by persons having ordinary skills in the technical field to which the present invention belongs.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0056] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified with "first," "second," etc., may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0057] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0058] Embodiments of the present application provide a contact lens that can be applied to the surface of the eyeball. When the contact lens is worn, a tear space can be formed between the contact lens and the front surface of the eyeball, so that the tear layer stored in the space forms a negative pressure, allowing the lens to fit more closely to the eyeball to prevent it from falling off.

[0059] The contact lens of this embodiment has an inner surface and an outer surface, and the outer surface is opposite to the inner surface. In addition, when the contact lens is worn, the inner surface faces the front surface of the eyeball.

[0060] In some examples, the contact lens can be designed with multiple zones, with three to five zones being the most common. In addition to the optical zone and the edge warping zone, the smooth connection zone between the two can be divided into more zones based on the optical correction or non-optical correction function achieved. In the embodiments of the present invention, the design of a scleral contact lens with four zones is taken as an example for illustration. Figure 1As shown, the inner surface 10 of a contact lens can have an optical zone (OZ), a transition zone, a landing zone, and an edge zone connecting the inner and outer surfaces. In some examples, the optical zone, transition zone, landing zone, and edge zone can be smoothly connected in sequence from the center outward. The design of a contact lens is not necessarily strictly symmetrical around the eye; that is, the design of each arc zone is non-rotationally symmetric. This allows for the design of a contact lens with regional anisotropy based on the surface characteristics of the eyeball being worn.

[0061] It can be understood that, based on the following concepts of the present invention, the contact lens in the present invention can be a scleral contact lens, a corneal contact lens or a corneoscleral contact lens.

[0062] The main concept of the present invention is to propose a design method for the inner and outer surfaces of the edge area. The overall design of the edge area affects the channel for tear exchange, which can help improve the circulation and oxygen permeability of tears and protect the health of the eyeball.

[0063] like Figure 2 As shown in the prior art, the edge area is generally set by a circular arc transition design method, that is, the smooth connection between the inner surface 14 and the outer surface 24 in the edge area is a circular arc transition design method. In order to clearly show the circular structure of the edge area of the prior art, Figure 2 The structure of another partial arc having the same diameter as the edge region in the prior art is also shown by a dotted line.

[0064] Continue to combine Figure 2 To explain, this arc transition design approach primarily addresses the need for a smooth connection between the two to facilitate processing. Generally, tear flow is considered separately in the curve design of the inner and outer surfaces 14 and 24. However, the curve design of the inner and outer surfaces of the edge region is also relevant to the flow of oxygen-carrying tears and should be factored into the overall design of the edge region.

[0065] Based on this, the present invention proposes a contact lens, which at least includes an optical zone, a transition zone, a landing zone, and a marginal zone. The optical zone, transition zone, and landing zone of the contact lens involved in the present disclosure can be any design in the art. The corresponding designs of the optical zone, transition zone, and landing zone can be characterized by the corresponding curve equations of the inner and outer surfaces within their respective areas. The transition zone is represented as the middle area connecting the optical zone and the landing zone, which can represent one or more segments. For example, the transition zone corresponds to the mid-peripheral area of the scleral lens in a certain design; and corresponds to the mid-peripheral area and the limbal area of the scleral lens in another design.

[0066] Figure 3 This is a schematic diagram of the edge area of a contact lens on an axial section. Figure 3The structure and design method of a contact lens according to the present disclosure are described. The axial section of the contact lens is a first plane that passes through the center point of the contact lens and the radially outermost point of the outer edge (the outer edge point), and is parallel to the longitudinal axis of the contact lens. The outer edge refers to the region where the inner surface of the edge region connects to the outer surface of the edge region.

[0067] exist Figure 3 In the contact lens structure shown, a plurality of points are involved in the first plane curve segment, and the points have spatial coordinates, including but not limited to:

[0068] P5 (sagittal point on the outer surface of the eyeball): This point is opposite to the outermost point of the maximum radial length of the contact lens, and the abscissa value of this point is the radius of the contact lens;

[0069] P0 (outer edge point of the marginal zone): This is the outer edge point of the marginal zone in the radial direction. It corresponds to the outer edge point of the maximum radial length of the marginal zone design. Once the radius (or diameter) and the total sagittal height of the contact lens are determined, the P0 point is determined.

[0070] Based on the above P0P5, a straight line is determined, and the straight line is an auxiliary line on the axial section to assist in the execution of the inner and outer surface curve design.

[0071] In this application, the sagittal direction corresponds to the -Y axis direction. For example, a Y axis coordinate of -5 indicates a sagittal of 5. The sagittal reference point (the origin of the coordinates) corresponds to the center point of the inner surface of the contact lens. The diameter direction perpendicular to the sagittal direction corresponds to the ±X axis.

[0072] On the auxiliary line, the scale model is optimized and designed to determine the positions of P1 and P3. Specifically, let P1P0 / P1P3=p, where the positions of P1 and P3 satisfy 0.37<p<0.59, and preferably p<0.5.

[0073] P1 (inner surface fitting point): the point on the auxiliary line used to fit the inner surface;

[0074] P3 (external surface fitting point): the point on the auxiliary line used to fit the external surface;

[0075] P2 (inner surface point): the first connection point between the inner surface 14 of the edge area and the previous design area (also called the inner surface connection point);

[0076] P4 (outer surface point): the second connection point between the outer surface 24 of the edge area and the previous design area (also called the outer surface connection point);

[0077] In a specific embodiment of the contact lens of the present invention, in a specific edge zone structure, the radial length between P2 and P0 is d1, and the radial length between P4 and P0 is d2. Generally, d1 is set to be greater than d2. In a specific embodiment, d1 is preferably 0.25-0.8 mm, and d2 is correspondingly 0.1-0.6 mm. Once d1 and d2 are set, the X-axis coordinates of P2 and P4 are determined. The Y-axis coordinates of P2 and P4 can be obtained based on the curve equation of the landing zone.

[0078] In this application, the term "radial length" refers to the distance between the projections of two points on a straight line perpendicular to the sagittal height direction. In a specific embodiment, the term "radial length" refers to the absolute value of the difference between the abscissas (X-axis coordinates) of the two points in a coordinate system having the center point of the inner surface of the contact lens as the coordinate origin, the sagittal height direction as the ordinate, and the diameter direction perpendicular to the sagittal height direction as the abscissa.

[0079] In the present invention, the points for fitting the inner and outer surface curve segments are selected based on the ratio of the auxiliary lines, defining P1P0 / P1P3 = p. The positions of P1 and P3 satisfy 0.37 < p < 0.59, preferably between 0.3 and 0.5, and more preferably between 0.37 and 0.45. This generally places the outer edge of the peripheral region closer to the inner surface. The selection of the P value is related to ocular surface parameters, the radius of the contact lens, and the distance (P0P5) between the outer edge of the lens and the ocular surface. According to the inventors' clinical validation, a larger P value improves tear flow, while a smaller P value improves wearing comfort. Based on this, the selected P value, combined with ocular surface parameters, the radius of the contact lens, and the distance (P0P5) between the outer edge of the lens and the ocular surface, should balance tear flow and comfort requirements, ensuring that the contact lens facilitates the flow of oxygen-carrying tears while also improving wearing comfort.

[0080] In a specific embodiment, the straight line P2P1 defined by the first connection point P2 of the inner surface of the edge area and the landing area and the second fitting point P1 is tangent to the contour curve of the inner surface of the edge area at the position of the first connection point P.

[0081] In a specific embodiment, the straight line P4P3 defined by the outer surface of the edge area and the second connection point P4 of the landing area and the first fitting point P3 is tangent to the contour curve of the outer surface of the edge area at the position of the second connection point P4.

[0082] In another embodiment, the present invention provides a method for designing a contact lens, comprising:

[0083] S1: Determine the auxiliary design line P5P0 for fitting the inner and outer surfaces of the edge area;

[0084] S2: Determine the second fitting point P1 corresponding to the inner surface and the first fitting point P3 corresponding to the outer surface on the auxiliary design line in proportion;

[0085] S3: Determine a first connection point P2 between the inner surface 14 of the peripheral region and the previous design region, and a second connection point P4 between the outer surface 24 of the peripheral region and the previous design region using the optimized design scale model of the contact lens;

[0086] S4: Use P0P1P2 to fit the inner surface curve segment, and use P0P3P4 to fit the outer surface curve segment.

[0087] In this way, the design of the edge region is completed. In summary, the design of the edge region is converted into a fitting design of the inner and outer surfaces.

[0088] In one embodiment, the initial design structure of the contact lens is obtained as follows:

[0089] The method includes determining P0 and P5 on a uniaxial section of the contact lens by an initial marginal zone structure design, constructing an auxiliary design line by P5P0, and selecting an inner surface fitting point P1 and an outer surface fitting point P3 on the auxiliary design line by a ratio of a first distance P1P0 to a second distance P3P0.

[0090] If the ratio of the first distance to the second distance is 0.3 to 0.59, it is considered that the fitting point position meets the range, and the fitting of the inner surface segment and the outer surface segment can be performed based on this.

[0091] As a preferred embodiment of the present invention, it is also possible to check whether the position of the selected fitting point meets the range by judging the ratio of d1 and d2. If d1 is greater than d2, it is considered that the coordinates of the fitting point selected by the optimized design scale model meet the range, where the radial line segment distance between P2 and P1 is d1, and the radial line segment distance between P4 and P3 is d2.

[0092] The first and second connection points P2 and P4 are obtained from the connection between the previous initial design area and the initial edge area structure design of a contact lens.

[0093] The inner surface curve segment is fitted with P0P1P2, and the outer surface curve segment is fitted with P0P3P4. Together with the initial edge area structure design, the edge area design is completed. P0' and P5' are updated to enter the next iterative optimization design to select the edge area design output with the best design indicators.

[0094] In a specific embodiment, the proportion number p in the optimized design proportion model may or may not be updated during the iterative calculation. The stopping condition for the iterative calculation may be set as follows: the selected p makes P4P3 tangent to the outer surface P4P0 of the lens edge at point P4, and / or makes P2P1 tangent to the inner surface P2P0 of the lens edge at point P2.

[0095] The specific implementation of step S4 is as follows:

[0096] For the inner surface of the lens edge (from P2 to P0, P2P0), the fitting curve can be used as follows:

[0097] B post (t) = (1-t) 2 P2+2t(1-t)P1+t 2 P0,t∈[0,1]

[0098] The outer surface of the lens edge (from P4 to P0, P4P0)) can be fitted with the following formula:

[0099] B ant (t) = (1-t) 2 P4+2t(1-t)P3+t 2 P0;

[0100] Where t is a fitting parameter, and the above P2P1P0, P4P3P0 are fitting point coordinates, or a fitting matrix formed by multiple fitting points on radial sections of multiple contact lenses. In this way, the fitting of the entire marginal area is completed.

[0101] In one embodiment, the present invention provides a method for designing a contact lens, comprising:

[0102] S10: determining the diameter of the contact lens, the outer edge point P0 of the contact lens, and the eye sagittal point P5 corresponding to the outer edge point P0 based on the wearer's ocular surface parameters;

[0103] S20: obtaining a plurality of fitting points corresponding to the inner surface of the edge area and the outer surface of the edge area respectively,

[0104] In a radial cross section of the contact lens,

[0105] The fitting points of the outer surface of the edge area are:

[0106] The first fitting point P3, the outer edge point P0 on the outer edge, and

[0107] A second connection point P4 between the outer surface of the edge area and the landing area;

[0108] The inner surface fitting points of the edge area are:

[0109] a second fitting point P1, an outer edge point P0 on the outer edge portion, and a first connection point P2 between the inner surface of the edge area and the landing area;

[0110] The edge region has a structure that is smoothly or non-smoothly connected to the landing region, the edge region includes an inner edge region surface close to the surface of the eyeball and an outer edge region surface away from the surface of the eyeball, and the position where the inner edge region surface and the outer edge region surface are connected forms the outer edge of the contact lens;

[0111] The first fitting point P3 and the second fitting point P1 are located on an auxiliary line;

[0112] The auxiliary line is determined by the outer edge point P0 on the outer edge portion and the eye sagittal point P5 corresponding to the outer edge point P0;

[0113] The first fitting point P3 and the second fitting point P1 define a first distance P3P1;

[0114] The second fitting point P1 and the outer edge point P0 define a second distance P1P0;

[0115] The second distance P1P0 and the first distance P3P1 have a ratio;

[0116] S30: Generating a first designed curved surface of the inner surface of the edge area and a second designed curved surface of the outer surface of the edge area by fitting the plurality of fitting points.

[0117] Furthermore, the ratio of the second distance P1P0 to the first distance P3P1 ranges from 0.3 to 0.59, preferably from 0.3 to 0.5, and more preferably from 0.37 to 0.45.

[0118] In a specific embodiment, the contact lens design method further includes selecting a ratio of the second distance P1P0 to the first distance P3P1 so that a straight line defined by the first connection point P2 and the second fitting point P1 is tangent to the first design curved surface at the first connection point P2;

[0119] In a specific embodiment, the contact lens design method further includes selecting a ratio of the second distance P1P0 to the first distance P3P1 so that the straight line defined by the second connection point P4 and the first fitting point P3 is tangent to the second design surface at the second connection point P4.

[0120] In a most preferred embodiment, the curve equation of the marginal area of the contact lens is obtained by the following process:

[0121] Step 1: Set the diameter and total sagittal height of the contact lens based on the human eye morphology. At this point, the coordinates of the outer edge point P0 on the outer edge of the contact lens and the horizontal coordinates of the first fitting point P3 and the second fitting point P1 on the auxiliary line can be obtained.

[0122] Step 2: Set the ratio P between the first distance P1P0 and the second distance P3P1 to obtain the vertical coordinates of the first fitting point P3 and the second fitting point P1. The distance between P3P1 represents the thickness of the contact lens' peripheral region. The ratio of the first distance P1P0 to the second distance P3P0 can be set based on the desired thickness of the contact lens' peripheral region as prescribed by the contact lens prescription.

[0123] Step 3: Set the initial values of d1 and d2 to determine the initial horizontal coordinates of the inner surface connection point P2 (first connection point) and the outer surface connection point P4 (second connection point), and obtain the initial vertical coordinates of P2 and P4 based on the curve equation of the landing area of the contact lens and the initial horizontal coordinates of P2 and P4.

[0124] Step 4: Connect the inner surface connection point P2 (first connection point) and the second fitting point P1 to form a line segment P2P1; connect the outer surface connection point P4 (second connection point) and the first fitting point P3 to form a line segment P4P3;

[0125] Determine whether line segment P2P1 is tangent to the corresponding curve on the inner surface of the landing area at point P2. If so, define the coordinates of P2 as the target coordinates. If not, return to steps 3 to 4 until the target coordinates of P2 are found.

[0126] Determine whether line segment P4P3 is tangent to the curve of the outer surface of the landing area at P4. If so, define the coordinates of P4 as the target coordinates. If not, return to steps 3 to 4 until the target coordinates of P4 are found.

[0127] According to the target coordinates of P2 and P4 and the coordinates of the outer edge point P0, the curve equations of the inner and outer surfaces of the edge area are obtained based on the following formulas:

[0128] B post (t) = (1-t) 2 P2+2t(1-t)P1+t 2 P0, t∈[0,1]

[0129] B ant (t) = (1-t) 2 P4+2t(1-t)P3+t 2 P0.

[0130] The design method implemented in this invention achieves a uniform change in lens edge thickness, with smooth curve connections, promoting tear exchange while meeting clinical edge warping requirements. It also significantly reduces lens peripheral thickness and increases lens oxygen permeability.

[0131] To illustrate the difference between the edge of the lens according to the present application and the edge of the lens of the prior art, see Figure 4 Under the same edge thickness, the new design of the present application and the traditional arc design have the same edge shape. The peripheral thickness of the lens of the present application is thinner and the change rate is uniform, which is conducive to tear exchange.

[0132] In addition, in the lens design of the present application, changes to the outer edge of the lens will not change the design of other parts of the contact lens that have optical effects and adsorption effects.

[0133] The above description of the embodiments is intended to facilitate understanding and application of the present invention by those skilled in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and improvements and modifications made by those skilled in the art based on the disclosure without departing from the scope and spirit of the present invention are within the scope of the present invention.

Claims

1. A contact lens comprising: an optical zone having the basic structure of the contact lens and having an optically corrective effect; a landing zone, the landing zone providing positioning for the contact lens; a transition zone connecting the optical zone and the landing zone and realizing auxiliary positioning and / or auxiliary optical correction when the contact lens is worn; Characterized in that the contact lens further comprises: a peripheral region, the peripheral region having a structure smoothly or non-smoothly connected to the landing region, the peripheral region including an inner peripheral region surface close to the surface of the eyeball and an outer peripheral region surface away from the surface of the eyeball, and the position where the inner peripheral region surface and the outer peripheral region surface are connected forms the outer edge of the contact lens; In a radial cross-section of the contact lens, the peripheral region inner surface defines a peripheral region inner surface profile curve, the peripheral region inner surface profile curve extending a first distance between a first juncture point (P2) and an outer edge point (P0), and the peripheral region outer surface defines a peripheral region outer surface profile curve, the peripheral region outer surface profile curve extending a second distance between a second juncture point (P4) and the outer edge point (P0); The first connection point (P2) is the connection point between the inner surface of the edge area and the landing area, the second connection point (P4) is the connection point between the outer surface of the edge area and the landing area, and the intersection of the inner surface contour curve of the edge area and the outer surface contour curve of the edge area forms the outer edge point (P0); The outer surface contour curve of the edge region has a corresponding first fitting point (P3), and the inner surface contour curve of the edge region has a corresponding second fitting point (P1), the first fitting point (P3) and the second fitting point (P1) are located on an auxiliary line, and the auxiliary line is determined by an outer edge point (P0) on the outer edge portion and an eye sagittal point (P5) corresponding to the outer edge point (P0); The inner surface contour curve of the edge region and the outer surface contour curve of the edge region each have at least two different curvatures, and a radial length d1 of the inner surface contour curve is greater than a radial length d2 of the outer surface contour curve of the edge region; The first fitting point (P3) and the second fitting point (P1) define a first distance (P3P1), the second fitting point (P1) and the outer edge point (P0) define a second distance (P1P0), and a ratio of the second distance (P1P0) to the first distance (P3P1) ranges from 0.3 to 0.

59.

2. The contact lens according to claim 1, wherein The curvature of the outer surface contour curve monotonically increases along the second connection point (P4) to the outer edge point (P0), and the curvature of the inner surface contour curve monotonically decreases along the first connection point (P2) to the outer edge point (P0).

3. The contact lens according to claim 1, wherein The ratio of the second distance (P1P0) to the first distance (P3P1) ranges from 0.3 to 0.

5.

4. The contact lens according to claim 3, wherein The ratio of the second distance (P1P0) to the first distance (P3P1) ranges from 0.37 to 0.

45.

5. The contact lens according to claim 1, wherein The radial length d1 is 0.10-0.8 mm, and d2 is 0.05-0.6 mm.

6. The contact lens according to any one of claims 1 to 4, characterized in that The inner surface of the edge area has a first design curved surface, and the equation of the first design curved surface is as follows: B post (t)=(1-t) 2 P2+2t(1-t)P1+t 2 P0,t∈[0,1]; The outer surface of the edge area has a second design curved surface, and the equation of the second design curved surface is as follows: B ant (t)=(1-t) 2 P4+2t(1-t)P3+t 2 P0; Among them, P0 is the outer edge point; P1 is the second fitting point; P2 is the first connection point; P3 is the first fitting point; P4 is the second connection point; t is the fitting coefficient.

7. The contact lens according to claim 6, wherein The contact lens is a scleral contact lens, a corneal contact lens or a corneoscleral contact lens.

8. The contact lens according to any one of claims 1 to 4, characterized in that A straight line (P2P1) defined by a first connection point (P2) of the inner surface of the edge region and the landing region and the second fitting point (P1) is tangent to a contour curve of the inner surface of the edge region at the position of the first connection point (P2); And / or, the straight line (P4P3) defined by the second connection point (P4) of the outer surface of the edge area and the landing area and the first fitting point (P3) is tangent to the contour curve of the outer surface of the edge area at the position of the second connection point (P4).

9. A contact lens design method, characterized in that: The method comprises the following steps: S10: determining the diameter of the contact lens, the outer edge point (P0) of the contact lens, and the eye sagittal point (P5) corresponding to the outer edge point (P0) based on the wearer's ocular surface parameters; S20: obtaining a plurality of fitting points corresponding to the inner surface of the edge area and the outer surface of the edge area respectively, In a radial cross section of the contact lens, The fitting points of the outer surface of the edge area are: The first fitting point (P3), the outer edge point (P0) on the outer edge, and a second connection point (P4) between the outer surface of the edge region and the landing region; The inner surface fitting points of the edge area are: a second fitting point (P1), an outer edge point (P0) on the outer edge portion, and a first connection point (P2) between the inner surface of the edge area and the landing area; The edge region has a structure that is smoothly or non-smoothly connected to the landing region, the edge region includes an inner edge region surface close to the surface of the eyeball and an outer edge region surface away from the surface of the eyeball, and the position where the inner edge region surface and the outer edge region surface are connected forms the outer edge of the contact lens; The first fitting point (P3) and the second fitting point (P1) are located on an auxiliary line; The auxiliary line is determined by the outer edge point (P0) on the outer edge portion and the eye sagittal point (P5) corresponding to the outer edge point (P0); The first fitting point (P3) and the second fitting point (P1) define a first distance (P3P1); The second fitting point (P1) defines a second distance (P1P0) from the outer edge point (P0); The ratio of the second distance (P1P0) to the first distance (P3P1) ranges from 0.3 to 0.59; S30: Generating a first designed curved surface of the inner surface of the edge area and a second designed curved surface of the outer surface of the edge area by fitting the plurality of fitting points.

10. The contact lens design method according to claim 9, wherein: selecting a ratio of the second distance (P1P0) to the first distance (P3P1) so that a straight line defined by the first connection point (P2) and the second fitting point (P1) is tangent to the first design curved surface at the first connection point (P2); And / or, the ratio of the second distance (P1P0) to the first distance (P3P1) is selected so that the straight line defined by the second connection point (P4) and the first fitting point (P3) is tangent to the second design surface at the second connection point (P4).

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