Orthokeratology lens design method and design device

Abstract

The present invention provides a design method and a design device for orthokeratology lenses. The method includes obtaining the actual refractive error degree, pupil radius, corneal horizontal visible iris diameter, the average of the first, second and third curvatures, and the maximum and minimum values ​​of the second curvature; determining the curvature and radius of the base arc segment according to the pupil radius, visual adjustment factor, the average of the first curvature, the actual refractive error degree and the overcorrection coefficient; determining the radius and curvature of the reverse arc segment according to the actual refractive error degree; determining the radius and curvature of the first and second positioning arc segments according to the corneal horizontal visible iris diameter and the average of the second and third curvatures; determining the arc segment width radius of the peripheral arc segment according to the comfort factor; and determining the curvature of the peripheral arc segment according to the correction parameter and the average curvature of the corneal position in the peripheral arc area; and determining the amount of annular curvature according to the maximum and minimum values ​​of the second curvature. Designing a lens that best matches the cornea based on the real corneal parameters to achieve better lens refractive correction.

Description

Technical Field

[0001] The present invention belongs to the technical field of orthokeratology lenses, and in particular relates to a design method and a design device for orthokeratology lenses. Background Art

[0002] Orthokeratology (Ortho-K) is a technique that uses specially designed orthokeratology lenses to actively, step by step, gradually and scientifically change the overall shape of the cornea in order to quickly improve naked eye vision. After wearing the lenses, the reverse arc area forms a defocus ring, so that light rays form myopic defocus at the peripheral fundus, increase the peripheral aberration of the image, and control the development of myopia in adolescents.

[0003] Modern orthokeratology lenses adopt the "reverse geometry" design principle, which designs the inner surface shape of orthokeratology lenses to be opposite to the geometric shape of the front surface of the cornea, creates some gaps between the lens and the cornea, and uses the mechanical effect of tears to achieve the "corrective" effect. Orthokeratology lenses are hard glasses. After wearing, a layer of unevenly distributed tears is sandwiched between the inner surface of the lens and the outer surface of the cornea. The fluid mechanics of tears pulls the epithelial cells in the center of the cornea to the mid-periphery (periphery); at the same time, when closing the eyes and blinking, the action of the eyelids causes the center of the lens to exert a certain pressure on the cornea below. These two effects cause the central curvature of the cornea to flatten, the central epithelial layer to thin, the mid-periphery to thicken, and the image point of the object moves closer to the retina. After wearing for a period of time, the shape of the front surface of the cornea tends to be consistent with the back surface of the orthokeratology lens. When the hard gas-permeable contact lens for orthokeratology is removed, the cornea still maintains the shape of the back surface of the orthokeratology lens, thereby reducing or even eliminating the degree of myopia. This change in shape is short-term, and the cornea will return to its previous shape when you stop wearing orthokeratology lenses.

[0004] The "reverse geometry" design of orthokeratology lenses was proposed by Stoyan in 1989 (US4952045). The original reverse geometry design divided orthokeratology lenses into three arc zones, including the base arc, the reverse arc, and the peripheral arc. Figure 1 1 is a schematic diagram of the longitudinal center section of a prior art orthokeratology lens with a four-arc design on the inner surface. Figure 1 As shown in the figure, the base arc area 1 contacts the central area of ​​the human cornea, has a relatively flat surface shape, and is used to flatten the corneal surface; the reversal arc area 2 is relatively steep, and is used to stabilize the flattening effect of the base arc and ensure a certain amount of tear storage; the positioning arc area 3 can also be called the fitting arc area, which is mainly used to stabilize the lens; the peripheral arc area 4 ensures the circulation of tears around the cornea and the orthokeratology lens.

[0005] However, in the above-mentioned prior art, since the design itself is designed with reference to the corneal big data, a certain change value (e value is about 0.4-0.6) is designed for the cornea, and in fact the change of each cornea is different, such as Figure 1 In the figure, the intersection of the inversion arc zone 2 and the circumferential arc zone 4, the arc of the circumferential arc zone 4, if the design is calculated based on big data, the designed orthokeratology lens may not match the actual cornea, which will eventually lead to lens instability and increased mechanical damage to the cornea.

[0006] At present, the design of lenses still relies on some simple trial lenses for matching design, which is very backward. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art and provide a corneal reshaping lens design method and design device.

[0008] In one aspect of the present invention, a method for designing orthokeratology lenses is provided, wherein the orthokeratology lenses include a base arc segment, a reverse arc segment, a first positioning arc segment, a second positioning arc segment and a peripheral arc segment arranged in sequence from inside to outside; the method includes:

[0009] Obtaining the actual refractive error degree of the user's cornea, the pupil radius, the diameter of the visible iris at the cornea level, the average first curvature of the central area, the average second curvature of the first positioning arc segment, the average third curvature of the second positioning arc segment, and the average curvature of the peripheral arc;

[0010] Determine the arc segment width radius of the base arc segment according to the pupil radius and the preset vision adjustment factor; and determine the curvature of the base arc segment according to the first curvature mean value, the actual refractive error degree and the overcorrection coefficient;

[0011] Determine the arc segment width radius of the reverse arc segment according to the magnitude relationship between the actual refractive error and the standard refractive power; and determine the curvature of the reverse arc segment according to a preset functional relationship between the curvature of the reverse arc segment and the arc segment width radius and curvature of the base arc segment;

[0012] Determine the arc width radius of the first positioning arc segment according to the corneal horizontal visible iris diameter; and determine the curvature of the first positioning arc segment according to the functional relationship between the curvature of the first positioning arc segment and the second curvature mean value;

[0013] Determine the arc segment width radius of the second positioning arc segment according to the corneal horizontal visible iris diameter and the arc segment width radii of the base arc segment, the inversion arc segment, the first positioning arc segment and the peripheral arc segment; and determine the arc segment width radius of the second positioning arc segment according to the functional relationship between the arc segment width of the second positioning arc segment and the third curvature mean value;

[0014] Determine the arc width radius of the peripheral arc segment according to a preset comfort factor; and determine the curvature of the peripheral arc segment according to the correction parameter and the mean value of the curvature of the peripheral arc;

[0015] Determining the value of the loop curvature according to the maximum value and the minimum value of the second curvature;

[0016] The design of the orthokeratology lens is completed based on the determined parameters of each arc segment and the amount of curvature.

[0017] Optionally, the arc segment width radius and radian of the base arc segment are determined respectively according to the following relationship:

[0018] BCJ = Pr + a;

[0019] BCR=337.5 / (FK-RX-PW)

[0020] Among them, BCJ is the arc width radius of the base arc segment; Pr is the pupil radius; a is the vision adjustment factor, which is 0 to 3 mm; BCR is the curvature of the base arc segment; FK is the first curvature mean; RX is the actual refractive error degree; PW is the overcorrection value.

[0021] Optionally, the overcorrection value satisfies the following relationship:

[0022] When 1.00D<RX≤3.00D, PW=(1.25~2.25)D;

[0023] When 3.00D<RX≤6.00D, PW=(0.75~1.5)D.

[0024] Optionally, the arc segment width radius of the reverse arc segment is determined according to the following relationship:

[0025] When 0.25D<RX≤1.00D, RCJ=0.25mm~0.65mm;

[0026] When 1.00D<RX≤3.00D, RCJ=0.3mm~0.7mm;

[0027] When 3.00D<RX≤6.00D, RCJ=0.4mm~0.8mm;

[0028] Among them, RCJ is the arc segment width radius of the reverse arc segment; RX is the actual refractive error degree.

[0029] Optionally, the arc length of the reverse arc segment is determined according to the following relationship:

[0030]

[0031] Among them, RCR is the radian of the reverse arc segment; BCJ is the arc segment width radius of the base arc segment; BCR is the radian of the base arc segment; b is the correction parameter, 0.3068<b<4.862.

[0032] Optionally, the arc segment width radius and curvature of the first positioning arc segment are determined according to the following relationship:

[0033] When 12mm<HVID<12.8mm, AC1J=0.6mm~1.0mm;

[0034] When 11.2mm<HVID<12mm, AC1J=0.5mm~0.9mm;

[0035] AC1R=337.5 / SAC1;

[0036] Among them, HVID is the horizontal visible iris diameter of the cornea; AC1J is the arc segment width radius of the first positioning arc segment; AC1R is the curvature of the first positioning arc segment, and SAC1 is the second curvature mean.

[0037] Optionally, the arc segment width radius and curvature of the second positioning arc segment are determined according to the following relationship:

[0038] AC2J=(HVID-1.2) / 2-BCJ-RCJ-AC1J-PCJ;

[0039] AC2R=337.5 / SAC2;

[0040] Among them, AC2J is the arc width radius of the second positioning arc segment; HVID is the horizontal visible iris diameter of the cornea; BCJ is the arc width radius of the base arc segment; RCJ is the arc width radius of the reversal arc segment; AC1J is the arc width radius of the first positioning arc segment; PCJ is the arc width radius of the peripheral arc segment; AC2R is the curvature of the second positioning arc segment; SAC2 is the third curvature mean.

[0041] Optionally, the arc segment width radius and radian of the peripheral arc segment are determined according to the following relationship:

[0042] PCJ = s = 0.2 mm to 0.7 mm;

[0043] PCR = 337.5 / SPC + c;

[0044] Among them, PCJ is the arc segment width radius of the peripheral arc segment; s is the comfort factor; PCR is the curvature of the peripheral arc segment; SPC is the mean curvature of the peripheral arc; c is the correction parameter, 1.625<c<4.663.

[0045] Optionally, the loop curvature is determined according to the following relationship:

[0046] CLY=K2-K1;

[0047] Wherein, CLY is the loop curvature; K1 is the minimum value of the second curvature; K2 is the maximum value of the second curvature.

[0048] Another aspect of the present invention provides a device for designing orthokeratology lenses, wherein the orthokeratology lenses include a base arc segment, a reverse arc segment, a first positioning arc segment, a second positioning arc segment and a peripheral arc segment arranged in sequence from the inside to the outside; the device includes:

[0049] An acquisition module, used to acquire the actual refractive error degree of the user's cornea, the pupil radius, the diameter of the visible iris at the cornea level, the first curvature mean of the central area, the second curvature mean of the first positioning arc segment, the third curvature mean of the second positioning arc segment, and the curvature mean of the peripheral arc;

[0050] A calculation module, configured to determine the arc segment width radius of the base arc segment according to the pupil radius and a preset vision adjustment factor; and to determine the curvature of the base arc segment according to the first curvature mean value, the actual refractive error degree and an overcorrection coefficient;

[0051] The calculation module is further used to determine the arc segment width radius of the reverse arc segment according to the size relationship between the actual refractive error degree and the standard refractive power; and determine the curvature of the reverse arc segment according to a preset functional relationship between the curvature of the reverse arc segment and the arc segment width radius and curvature of the base arc segment;

[0052] The calculation module is further used to determine the arc segment width radius of the first positioning arc segment according to the corneal horizontal visible iris diameter; and determine the curvature of the first positioning arc segment according to the functional relationship between the curvature of the first positioning arc segment and the second curvature mean value;

[0053] The calculation module is further used to determine the arc segment width radius of the second positioning arc segment according to the corneal horizontal visible iris diameter and the arc segment width radii of the base arc segment, the inversion arc segment, the first positioning arc segment and the peripheral arc segment; and determine the curvature of the second positioning arc segment according to the functional relationship between the curvature of the second positioning arc segment and the third curvature mean value;

[0054] The calculation module is further used to determine the arc segment width radius of the peripheral arc segment according to a preset comfort factor; and determine the curvature of the peripheral arc segment according to the correction parameter and the mean curvature of the peripheral arc;

[0055] The calculation module is further used to determine the value of the loop curvature according to the maximum value and the minimum value of the second curvature;

[0056] The design module is used to design orthokeratology lenses based on the determined parameters of each arc segment and the amount of toroidal curvature.

[0057] The orthokeratology lens design method and design device of the embodiment of the present invention propose a new lens design method, which collects the arc segment parameters of the lens covering the corneal area, eliminates the method of linking the lens itself with big data, and eliminates the method of visual inspection by the fitter, and performs a new design of the lens based on the real curvature of each arc segment of the cornea of ​​each fitter collected. The purpose is to truly design a lens that best matches the cornea based on the real corneal parameters, thereby achieving better refractive correction of the lens, higher vision and myopia control effects, reduced mechanical friction between the lens and the cornea, increased lens comfort, and better lens positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 A schematic longitudinal center cross-sectional view of a prior art orthokeratology lens designed with four arc zones on the inner surface;

[0059] Figure 2 It is a schematic structural diagram of a corneal reshaping lens according to an embodiment of the present invention;

[0060] Figure 3 A flowchart of a method for designing orthokeratology lenses according to another embodiment of the present invention;

[0061] Figure 4 A schematic diagram of an actual corneal section according to another embodiment of the present invention;

[0062] Figure 5 A schematic diagram of corneal curvature distribution calculation according to another embodiment of the present invention;

[0063] Figure 6 A schematic diagram of fitting a lens and a cornea according to another embodiment of the present invention;

[0064] Figure 7 A schematic diagram of the value of each arc area according to another embodiment of the present invention;

[0065] Figure 8 A schematic diagram of a process for determining orthokeratology lens fitting parameters according to another embodiment of the present invention;

[0066] Fig. 9 This is a schematic structural diagram of a corneal refractive therapy lens design device according to another embodiment of the present invention. DETAILED DESCRIPTION

[0067] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0068] like Figure 2 and Figure 3 As shown, an embodiment of the present invention is a method for designing a corneal reshaping lens, wherein the corneal reshaping lens 100 includes a base arc segment 110, a reverse arc segment 120, a first positioning arc segment 130, a second positioning arc segment 140 and a peripheral arc segment 150 which are arranged in sequence from inside to outside.

[0069] like Figure 3 As shown, the method S100 includes the following specific steps:

[0070] S110, obtaining the actual refractive error degree of the user's cornea, the pupil radius, the diameter of the visible iris at the cornea level, the first curvature mean of the central area, the second curvature mean of the first positioning arc segment, the third curvature mean of the second positioning arc segment, and the curvature mean of the peripheral arc.

[0071] Specifically, in this step, Figure 4 , Figure 5 and Figure 7 , the actual refractive error of the cornea of ​​the user to be fitted can be obtained through a computer ophthalmometer and other equipment, and the pupil radius of the user's cornea, the diameter of the visible iris at the cornea level, the first curvature mean of the central area, the second curvature mean of the first positioning arc segment, and the third curvature mean of the second positioning arc segment can be obtained according to the corneal topography. For example, the first curvature mean can be as follows Figure 4 The mean value of the corneal central 4 mm curvature is collected; Figure 7 As shown, the second curvature mean is the average value of the corneal curvature from BCJ+RCJ to BCJ+RCJ+ACJ1 on the cornea, and the third curvature mean is the average value of the curvature ring from the width of BCJ+RCJ+ACJ1 to BCJ+RCJ+AC1J+AC2J on the cornea.

[0072] S120. Determine the arc width radius of the base arc segment according to the pupil radius and a preset vision adjustment factor; and determine the curvature of the base arc segment according to the first curvature mean, the actual refractive error degree and the overcorrection coefficient.

[0073] Specifically, in this step, the parameter of the vision adjustment factor is the difference between the pupil size of the cornea and the width of the base curve segment of the lens. The arc width radius and curvature of the base curve segment can be determined according to the following relationship:

[0074] BCJ = Pr + a;

[0075] BCR=337.5 / (FK-RX-PW)

[0076] Among them, BCJ is the arc width radius of the base arc segment; Pr is the pupil radius; a is the vision adjustment factor, and its value is 0 to 3 mm. Preferably, the value is 1.4 mm; BCR is the curvature of the base arc segment; FK is the first curvature mean; RX is the actual refractive error degree; PW is the overcorrection value.

[0077] Wherein, the overcorrection value satisfies the following relationship:

[0078] When 1.00D<RX≤3.00D, PW=(1.25~2.25)D.

[0079] When 3.00D<RX≤6.00D, PW=(0.75~1.5)D.

[0080] In this step, when the refractive power is small, the difference in curvature between the lens and the cornea is small, and the defocus amount of corneal reshaping is small, which will affect the control effect. Appropriately increasing the PW value can enhance the control effect.

[0081] S130. Determine the arc segment width radius of the reverse arc segment according to the relationship between the actual refractive error and the standard refractive power; and determine the curvature of the reverse arc segment according to a preset functional relationship between the curvature of the reverse arc segment and the arc segment width radius and curvature of the base arc segment.

[0082] Specifically, in this step, the arc segment width radius of the reverse arc segment can be determined according to the following relationship:

[0083] When 0.25D<RX≤1.00D, RCJ=0.25mm~0.65mm, preferably, RCJ=0.45mm.

[0084] When 1.00D<RX≤3.00D, RCJ=0.3mm~0.7mm, preferably, RCJ=0.5mm.

[0085] When 3.00D<RX≤6.00D, RCJ=0.4mm~0.8mm; Preferably, RCJ=0.6mm.

[0086] Among them, RCJ is the arc segment width radius of the reverse arc segment; RX is the actual refractive error degree.

[0087] In this step, when the refractive power is small, the difference in curvature between the lens and the cornea is small, and the defocus amount of corneal reshaping is small, which will affect the control effect. Appropriately increasing the RCJ value can enhance the width of the defocus ring and increase the control effect.

[0088] Furthermore, the arc length of the reverse arc segment can be determined according to the following relationship:

[0089]

[0090] Among them, RCR is the radian of the reverse arc segment; BCJ is the arc segment width radius of the base arc segment; BCR is the radian of the base arc segment; b is the correction parameter, 0.3068<b<4.862.

[0091] In this step, the reverse arc is linked with the base arc design. No matter what changes occur in the base arc, they will be taken into account in the calculation to ensure the best positioning, vision and control effects of the lens.

[0092] S140. Determine the arc width radius of the first positioning arc segment according to the horizontal visible iris diameter of the cornea; and determine the curvature of the first positioning arc segment according to the functional relationship between the curvature of the first positioning arc segment and the mean value of the second curvature.

[0093] Specifically, in this step, the arc width radius and curvature of the first positioning arc segment may be determined according to the following relationship:

[0094] When 12 mm<HVID<12.8 mm, AC1J=0.6 mm~1.0 mm, preferably, AC1J=0.8 mm.

[0095] When 11.2 mm<HVID<12 mm, AC1J=0.5 mm~0.9 mm, preferably, AC1J=0.7 mm.

[0096] AC1R=337.5 / SAC1;

[0097] Among them, HVID is the horizontal visible iris diameter of the cornea; AC1J is the arc segment width radius of the first positioning arc segment; AC1R is the curvature of the first positioning arc segment, and SAC2 is the second curvature mean.

[0098] In this step, the lens AC1 is linked with the cornea size to ensure the best positioning effect of the lens.

[0099] S150. Determine the arc segment width radius of the second positioning arc segment based on the corneal horizontal visible iris diameter and the arc segment width radii of the base arc segment, the inversion arc segment, the first positioning arc segment and the peripheral arc segment; and determine the curvature of the second positioning arc segment based on the functional relationship between the curvature of the second positioning arc segment and the mean value of the third curvature.

[0100] Specifically, in this step, the arc width radius and curvature of the second positioning arc segment may be determined according to the following relationship:

[0101] AC2J=(HVID-1.2) / 2-BCJ-RCJ-AC1J-PCJ;

[0102] AC2R=337.5 / SAC2;

[0103] Among them, AC2J is the arc width radius of the second positioning arc segment; HVID is the horizontal visible iris diameter of the cornea; BCJ is the arc width radius of the base arc segment; RCJ is the arc width radius of the reversal arc segment; AC1J is the arc width radius of the first positioning arc segment; PCJ is the arc width radius of the peripheral arc segment; AC2R is the curvature of the second positioning arc segment; SAC2 is the third curvature mean.

[0104] S160. Determine the arc segment width radius of the peripheral arc segment according to a preset comfort factor; and determine the curvature of the peripheral arc segment according to the correction parameter and the mean curvature of the peripheral arc.

[0105] Specifically, in this step, the arc segment width radius and radian of the peripheral arc segment are determined according to the following relationship:

[0106] PCJ=s=0.2mm~0.7mm, preferably, PCJ=0.4mm.

[0107] PCR = 337.5 / SPC + c;

[0108] Among them, PCJ is the arc segment width radius of the peripheral arc segment; s is the comfort factor; PCR is the curvature of the peripheral arc segment; SPC is the mean curvature of the peripheral arc; c is the correction parameter, 1.625<c<4.663.

[0109] In this step, the peripheral curvature of the lens is calculated based on the optimal choice of comfort. This design method can achieve the optimal comfort while ensuring the breathability and tear exchangeability of the lens.

[0110] S170. Determine a value of the loop curvature according to the maximum value and the minimum value of the second curvature.

[0111] Specifically, in this step, the loop curvature amount can be determined according to the following relationship:

[0112] CLY=K2-K1;

[0113] Wherein, CLY is the loop curvature; K1 is the minimum value of the second curvature; K2 is the maximum value of the second curvature.

[0114] In this step, because the curvature of the cornea is irregular, the cornea is similar to an ellipse. All the previous K values ​​are taken from the part with a smaller curvature on the cornea, and the annular curvature is the mean of the larger curvature in the second curvature mean minus the mean of the smaller curvature. Both values ​​can be taken in the device.

[0115] S180. Complete the design of the orthokeratology lens according to the determined parameters of each arc segment and the amount of curvature.

[0116] The following is a specific example to illustrate the orthokeratology lens fitting method of the present invention.

[0117] For example Figure 8 Shown

[0118] Li

[0119] Refractive power: Right eye: 4.00D = RX

[0120] The data collected from the corneal topography are as follows:

[0121] Actual eye refractive error: 4.00D = RX

[0122] Pupil radius: PR = 1.3 mm

[0123] Diameter of iris visible at corneal level: HVID = 11.9 mm

[0124] First curvature mean: KF = 42.0

[0125] Second curvature mean: SAC1 = 41.5D

[0126] The maximum and minimum values ​​of the second curvature: CLY = 42.0-41.5 = 0.5D

[0127] Mean value of the third curvature: SAC2 = 39.2D

[0128] Average curvature of the corneal position in the peripheral arc area: SPC = 37.4

[0129] The relevant configuration parameters of the user shaping lens are as follows:

[0130] 1.PW=1.00D,BCR=337.5 / (FK-RX-PW)=9.12mm

[0131] 2. BCJ = pupil radius + 1.4 mm = 2.7

[0132] 3. When 3.00D<RX≤6.00D, RCJ=0.6mm

[0133] 4.

[0134] 5.ACJ1=0.7mm, SAC1=41.5D

[0135] 6.AC1R=337.5 / SAC1=8.13mm

[0136] 7.AC2J=(HVID-1.2) / 2-BCJ-RCJ-ACJ1-PCW=0.85mm

[0137] SAC2=39.2D

[0138] 8.AC2R=337.5 / SAC2=8.61mm

[0139] 9.PCW=0.4mm

[0140] SPC = 37.4

[0141] 10.PCR=337.5 / SPC+c=9.02+c=11.7mm

[0142] 11.CLY=42.0-41.5=0.5D

[0143] In summary

[0144] The data from 1-11 are linked with the actual corneal parameters to design accurate orthokeratology lenses, as shown in Table 1:

[0145] Table 1

[0146] BCR BCJ RCJ RCR ACJ1 AC1R AC2J AC2R PCW PCR CLY 9.12 2.7 0.6 6.81 0.7 8.13 0.85 8.61 0.4 11.7 0.5

[0147] The orthokeratology lens design method of the embodiment of the present invention proposes a new lens design method, which collects the arc segment parameters of the corneal area covered by the lens, cancels the method of linking the lens itself with big data, cancels the method of visual inspection by the fitter, and performs a new design of the lens based on the real curvature of each arc segment of the cornea of ​​each fitter collected. Its purpose is to truly design a lens that best matches the cornea based on the real corneal parameters, so as to achieve better refractive correction of the lens, higher vision and myopia control effects, reduce mechanical friction between the lens and the cornea, increase lens comfort, and better lens positioning.

[0148] Another aspect of the present invention, as Fig. 9 As shown, a corneal reshaping lens design device 200 is provided, which can be applied to the design method described above. For details, please refer to the relevant records in the above text, and no further description is given here. The device 200 includes an acquisition module 210, a calculation module 220 and a design module 230.

[0149] The acquisition module 210 is used to obtain the actual refractive error degree of the user's cornea, the pupil radius, the visible iris diameter at the cornea level, the first curvature mean of the central area, the second curvature mean of the first positioning arc segment, the third curvature mean of the second positioning arc segment, and the curvature mean of the peripheral arc.

[0150] The calculation module 220 is used to:

[0151] The arc segment width radius of the base arc segment is determined according to the pupil radius and a preset vision adjustment factor; and the curvature of the base arc segment is determined according to the first curvature mean, the actual refractive error degree and the overcorrection coefficient.

[0152] The arc segment width radius of the reverse arc segment is determined according to the size relationship between the actual refractive error degree and the standard refractive power; and the curvature of the reverse arc segment is determined according to a preset functional relationship between the curvature of the reverse arc segment and the arc segment width radius and curvature of the base arc segment.

[0153] The arc segment width radius of the first positioning arc segment is determined according to the horizontal visible iris diameter of the cornea; and the curvature of the first positioning arc segment is determined according to the functional relationship between the curvature of the first positioning arc segment and the mean value of the second curvature.

[0154] Determine the arc segment width radius of the second positioning arc segment based on the corneal horizontal visible iris diameter and the arc segment width radii of the base arc segment, the inversion arc segment, the first positioning arc segment and the peripheral arc segment; and determine the curvature of the second positioning arc segment based on the functional relationship between the curvature of the second positioning arc segment and the mean value of the third curvature.

[0155] The arc segment width radius of the peripheral arc segment is determined according to a preset comfort factor; and the curvature of the peripheral arc segment is determined according to the correction parameter and the mean value of the curvature of the peripheral arc.

[0156] The value of the loop curvature is determined according to the maximum value and the minimum value of the second curvature.

[0157] The design module 230 is used to design orthokeratology lenses based on the determined parameters of each arc segment and the amount of toricity.

[0158] The orthokeratology lens design device of this embodiment proposes a new lens design method, which collects the arc segment parameters of the corneal area covered by the lens, cancels the method of linking the lens itself with big data, cancels the method of visual inspection by the fitter, and performs a new design of the lens based on the real curvature of each arc segment of the cornea of ​​each fitter collected. Its purpose is to truly design a lens that best matches the cornea based on the real corneal parameters, so as to achieve better refractive correction of the lens, reduce the wearer's aberration to improve visual quality, reasonably design the wearer's defocus amount after shaping, achieve higher myopia control effect, reduce mechanical friction between the lens and the cornea, reduce the wearer's corneal risk, increase lens comfort, and better lens positioning.

[0159] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for designing orthokeratology lenses, It is characterized in that The orthokeratology lens comprises a base arc segment, a reverse arc segment, a first positioning arc segment, a second positioning arc segment and a peripheral arc segment arranged in sequence from inside to outside; the method comprises: Obtaining the actual refractive error degree of the user's cornea, the pupil radius, the diameter of the visible iris at the cornea level, the average first curvature of the central area, the average second curvature of the first positioning arc segment, the average third curvature of the second positioning arc segment, and the average curvature of the peripheral arc; Determine the arc segment width radius of the base arc segment according to the pupil radius and the preset vision adjustment factor; and determine the curvature of the base arc segment according to the first curvature mean value, the actual refractive error degree and the overcorrection coefficient; Determine the arc segment width radius of the reverse arc segment according to the magnitude relationship between the actual refractive error and the standard refractive power; and determine the curvature of the reverse arc segment according to a preset functional relationship between the curvature of the reverse arc segment and the arc segment width radius and curvature of the base arc segment; Determine the arc width radius of the first positioning arc segment according to the corneal horizontal visible iris diameter; and determine the curvature of the first positioning arc segment according to the functional relationship between the curvature of the first positioning arc segment and the second curvature mean value; Determine the arc segment width radius of the second positioning arc segment according to the corneal horizontal visible iris diameter and the arc segment width radius of the base arc segment, the inversion arc segment, the first positioning arc segment and the peripheral arc segment; and, determining the curvature of the second positioning arc segment according to a functional relationship between the curvature of the second positioning arc segment and the third curvature mean; Determining the arc segment width radius of the peripheral arc segment according to a preset comfort factor; and, determining the curvature of the arc segment of the peripheral arc according to the correction parameter and the mean curvature of the peripheral arc; Determine the value of the loop curvature according to the maximum value and the minimum value of the second curvature; According to the determined parameters of each arc segment and the toric amount, the design of the orthokeratology lens is completed; The arc width radius of the peripheral arc segment is determined according to the following relationship: PCJ=s=0.2mm~0.7mm; PCJ is the arc segment width radius of the peripheral arc segment; s is the comfort factor.

2. The method according to claim 1, It is characterized in that The arc width radius and radian of the base arc segment are determined according to the following relationship: BCJ=Pr+a; BCR=337.5 / (FK-RX-PW) Among them, BCJ is the arc width radius of the base arc segment; Pr is the pupil radius; a is the vision adjustment factor, and its value is 0~3mm; BCR is the curvature of the base arc segment; FK is the first curvature mean; RX is the actual refractive error degree; PW is the overcorrection value.

3. The method according to claim 2, It is characterized in that The overcorrection value satisfies the following relationship: When 0.00D<RX≤1.00D, PW = (1.50~2.25)D; When 1.00D<RX≤3.00D, PW = (1.25~2.25)D; When 3.00D<RX≤6.00D, PW = (0.75~1.5)D.

4. The method according to claim 1, It is characterized in that The arc width radius of the reverse arc segment is determined according to the following relationship: When 0.00D<RX≤1.00D, RCJ=0.25mm~0.65mm; When 1.00D<RX≤3.00D, RCJ=0.3mm~0.7mm; When 3.00D<RX≤6.00D, RCJ=0.4mm~1.0mm; Among them, RCJ is the arc segment width radius of the reverse arc segment; RX is the actual refractive error degree.

5. The method according to claim 1, It is characterized in that The arc length of the reverse arc segment is determined according to the following relationship: RCR= Among them, RCR is the radian of the reverse arc segment; BCJ is the arc segment width radius of the base arc segment; BCR is the radian of the base arc segment; b is the correction parameter, 0.3068<b<4.

862.

6. The method according to claim 1, It is characterized in that The arc width radius and curvature of the first positioning arc segment are determined according to the following relationship: When 12mm≤HVID<14.0mm, AC1J=0.6mm~1.0mm; When 10.2mm<HVID<12mm, AC1J=0.5mm~0.9mm; AC1R=337.5 / SAC1; Among them, HVID is the horizontal visible iris diameter of the cornea; AC1J is the arc segment width radius of the first positioning arc segment; AC1R is the curvature of the first positioning arc segment, and SAC1 is the second curvature mean.

7. The method according to claim 1, It is characterized in that The arc width radius and arc length of the second positioning arc segment are determined according to the following relationship: AC2J=(HVID-1.2) / 2-BCJ-RCJ-AC1J-PCJ; AC2R=337.5 / SAC2; Among them, AC2J is the arc width radius of the second positioning arc segment; HVID is the horizontal visible iris diameter of the cornea; BCJ is the arc width radius of the base arc segment; RCJ is the arc width radius of the reversal arc segment; AC1J is the arc width radius of the first positioning arc segment; PCJ is the arc width radius of the peripheral arc segment; AC2R is the curvature of the second positioning arc segment; SAC2 is the third curvature mean.

8. The method according to claim 1, It is characterized in that The arc segment radian of the peripheral arc segment is determined according to the following relationship: PCR=337.5 / SPC+c; Wherein, PCR is the curvature of the peripheral arc segment; SPC is the mean curvature of the peripheral arc; c is the correction parameter, 1.625<c<4.

663.

9. The method according to claim 1, It is characterized in that The amount of loop curvature is determined according to the following relationship: CLY=K2-K1; Wherein, CLY is the loop curvature; K1 is the minimum value of the second curvature; K2 is the maximum value of the second curvature.

10. A device for designing orthokeratology lenses, It is characterized in that The orthokeratology lens comprises a base arc segment, a reverse arc segment, a first positioning arc segment, a second positioning arc segment and a peripheral arc segment arranged in sequence from the inside to the outside; the device comprises; An acquisition module, used to acquire the actual refractive error degree of the user's cornea, the pupil radius, the diameter of the visible iris at the cornea level, the first curvature mean of the central area, the second curvature mean of the first positioning arc segment, the third curvature mean of the second positioning arc segment, and the curvature mean of the peripheral arc; A calculation module, used for determining the arc segment width radius of the base arc segment according to the pupil radius and a preset vision adjustment factor; and determining the curvature of the base curve segment according to the first curvature mean value, the actual refractive error degree and the overcorrection coefficient; The calculation module is further used to determine the arc segment width radius of the reverse arc segment according to the size relationship between the actual refractive error degree and the standard refractive power; and determine the curvature of the reverse arc segment according to a preset functional relationship between the curvature of the reverse arc segment and the arc segment width radius and curvature of the base arc segment; The calculation module is further used to determine the arc segment width radius of the first positioning arc segment according to the corneal horizontal visible iris diameter; and determine the curvature of the first positioning arc segment according to the functional relationship between the curvature of the first positioning arc segment and the second curvature mean value; The calculation module is further used to determine the arc segment width radius of the second positioning arc segment according to the corneal horizontal visible iris diameter and the arc segment width radii of the base arc segment, the inversion arc segment, the first positioning arc segment and the peripheral arc segment; and determining the curvature of the second positioning arc segment according to a functional relationship between the curvature of the second positioning arc segment and the third curvature mean; The calculation module is further used to determine the arc segment width radius of the peripheral arc segment according to a preset comfort factor; and determine the curvature of the peripheral arc segment according to the correction parameter and the mean curvature of the peripheral arc; The calculation module is further used to determine the value of the loop curvature according to the maximum value and the minimum value of the second curvature; A design module, for designing orthokeratology lenses according to the determined parameters of each arc segment and the toric amount; The arc width radius of the peripheral arc segment is determined according to the following relationship: PCJ=s=0.2mm~0.7mm; PCJ is the arc segment width radius of the peripheral arc segment; s is the comfort factor.

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