A method for designing scleral lenses based on ocular surface and scleral topography.

Abstract

This invention belongs to the field of contact lens technology, specifically providing a method for designing scleral lenses based on ocular surface and scleral topography. Based on the topography of the anterior surface of the patient's cornea and sclera, the method divides the anterior surface of the cornea and sclera into meridians at equal angles, and designs the surface profile curves of the anterior and posterior surfaces of the scleral lens according to the morphology of the patient's cornea and sclera. Finally, 3D reconstruction is used to obtain the 3D surface profile data of the scleral lens. The optical zone of the scleral lens can be designed in various ways depending on the different shapes of the patient's eyeball; the transition zone can be designed in diverse ways to ensure the thickness of the intraocular fluid at certain locations based on the ocular surface morphology; and the landing zone smoothly conforms to the anterior surface of the sclera. This invention maximizes conformity to the patient's ocular surface morphology, ensures the uniformity of the intraocular fluid, and maintains a high degree of matching with the ocular surface, thereby achieving trial-free scleral lens fitting, improving clinical accuracy and efficiency, and enhancing patient safety and satisfaction.

Description

Technical Field

[0001] This invention belongs to the field of contact lens technology, specifically relating to a method for designing scleral lenses based on ocular surface scleral topography. Background Technology

[0002] Currently, scleral lenses used in clinical practice are designed symmetrically, such as spherical or toroidal designs. However, in reality, the vast majority of patients have significant asymmetry in their ocular surface. Therefore, symmetrically designed lenses are unsuitable for patients with strong ocular surface asymmetry.

[0003] Furthermore, in clinical scleral lens fitting, a fixed model of scleral lens is selected for trial fitting, waiting, and observation. If it is not suitable, another model is tried and observed, and this process is repeated until a suitable scleral lens is found. There is no specific design of the scleral lens surface shape based on the patient's individual ocular surface morphology. Summary of the Invention

[0004] The purpose of this invention is to provide a method for designing scleral lenses based on ocular surface scleral topography.

[0005] To address the above problems, this invention provides a method for designing scleral lenses based on ocular surface scleral topography, comprising:

[0006] Obtain the anterior surface curve of the cornea and sclera in the OCT image of the eyeball, and perform 3D reconstruction of the anterior surface curve of the cornea and sclera to obtain the scleral topography map.

[0007] Meridians are extracted circumferentially from the scleral topography map; based on each meridian, the optical zone of the scleral lens is designed to obtain the optical zone curves of the front and rear surfaces of the scleral lens;

[0008] Based on the designed optical zone of the sclera, the transition zone of the posterior surface and the transition zone of the anterior surface of the sclera are designed to obtain the transition zone curves of the anterior and posterior surfaces of the sclera.

[0009] Based on the designed transition zone of the scleral lens, the landing zones of the posterior and anterior surfaces of the scleral lens are designed to obtain the landing zone curves of the anterior and posterior surfaces of the scleral lens.

[0010] The curves of the optical zone, transition zone and landing zone of the front and rear surfaces of the sclera are smoothed at the junctions of each zone to obtain the front surface curve and rear surface curve of the sclera calculated in pixel resolution.

[0011] After converting the anterior and posterior surface curves of the sclera to a polar coordinate system based on pixel resolution, they are then densified to obtain densified data. The densified data is then used for 3D reconstruction to obtain the corresponding 3D point cloud data of the sclera.

[0012] Furthermore, in the above method, the optical zone design of the scleral lens is based on each meridian, including:

[0013] Based on the pupil diameter, a first chord of horizontal length chord1 is taken. The first chord intersects the entire meridian of the anterior surface curve of the cornea at two points. The angles between the line connecting these two points and the center of the best-fit sphere of the cornea obtained from the scleral topography and the y-axis are α and β, respectively.

[0014] Based on the optical regions α+β of the posterior and anterior surfaces of the sclera, the chord length chord2 of the posterior surface region of the sclera and the chord length chord3 of the anterior surface region of the sclera are calculated.

[0015] Based on chord lengths chord1, chord2, and chord3, the range of the optical zone along the entire meridian is determined.

[0016] Furthermore, in the above method, the optical zone design of the scleral lens is based on each meridian, including:

[0017] Based on the pupil diameter, take a second chord with a horizontal length of chord1 / 2. The second chord intersects the anterior surface of the sclera at a point on the semimeridian. The angle between the line connecting this point and the center of the best-fit sphere of the cornea and the y-axis is α.

[0018] Based on the semi-meridian, the optical regions α of the posterior and anterior surfaces of the sclera are designed, and the chord lengths chord2 and chord3 of the posterior and anterior surfaces of the sclera are calculated.

[0019] Based on chord lengths chord1, chord2, and chord3, the range of the optical zone of the semimeridian is determined.

[0020] Furthermore, in the above method, based on chord lengths chord1, chord2, and chord3, the range of the optical zone along the entire meridian or half-meridian is determined, including:

[0021] The lengths of chord1, chord2, and chord3 are calculated as follows:

[0022] chord1:chord2:chord3=R1:R2:R3,

[0023] R1 is the radius of curvature of the best-fit sphere of the cornea obtained from the scleral topography;

[0024] R2 is the radius of curvature of the posterior surface of the scleral lens;

[0025] R3 is the radius of curvature of the anterior surface of the scleral lens;

[0026] R1, R2, and R3 have the following relationship:

[0027] R2-R1=ΔR 21 ;

[0028] R3-R2=ΔR 31 ;

[0029] Where, ΔR 21 Allow for thickness of the liquid under the microscope;

[0030] ΔR 31 sclLenThick is the central thickness of the scleral lens.

[0031] Furthermore, in the above method, the optical zone design of the scleral lens is based on each meridian, including:

[0032] Based on the pupil diameter, take a horizontal chord of length chord1. Make the chord lengths chord2 and chord3 of the posterior surface area of ​​the designed scleral lens equal to chord1. Based on the chord lengths chord1, chord2, and chord3, determine the range of the optical zone of the entire meridian.

[0033] Furthermore, in the above method, the optical zone design of the scleral lens is based on each meridian, including:

[0034] Based on the pupil diameter, take a horizontal chord with a length of chord1 / 2. Make the chord lengths of the posterior surface region of the scleral lens, chord2 / 2 and the anterior surface region of the designed scleral lens, chord3 / 2, equal to chord1 / 2. Based on the chord lengths chord1, chord2, and chord3, determine the range of the optical zone of the semimeridian.

[0035] Furthermore, in the above method, based on the designed optical zone of the scleral lens, the transition zone of the posterior surface of the scleral lens and the transition zone of the anterior surface of the scleral lens are designed, including:

[0036] Take a chord of horizontal length chord4, intersecting the anterior surface curve of the sclera at two points P on the left and right. landing_l And Planding_r; point P on the posterior surface of the sclera. sc_l Point Psc_r represents the edge of the optical zone on the posterior surface of the scleral lens. landing_l To point P sc_l Section and point P landing_r To point P sc_r The section, which is the transition area for scleral lenses, has the following chord4 values:

[0037] chord4 = WTW + ΔC1

[0038] Wherein, WTW is the white-to-white value of the eyeball, and ΔC1 is an empirical value greater than 0;

[0039] The vertical distance between the transition zone of the posterior surface of the sclera and the anterior surface of the cornea and sclera is determined by P. sc_l Vertical distance d to the anterior surface of the cornea and sclera sc_l Decrease gradually and evenly to 0:

[0040] d = d sc_l / (x sc_l -x landing_l )*(xx sc_l )

[0041] y = y secler -d sc_l

[0042] Among them, y sc_l and x sc_l For P sc_l The coordinates;

[0043] y landing_l and x landing_l For P landing_l The coordinates;

[0044] d is line segment P sc_l Point P landing_l The vertical gap between the posterior surface of the sclera and the anterior surface of the cornea and sclera at any x point;

[0045] y secler Let x be the vertical coordinate on the anterior surface of the sclera at any x.

[0046] y and x are from point P sc_l Point P landing_l The coordinates of any point in the transition region;

[0047] Based on the curve of the transition zone on the posterior surface of the sclera, the thickness ΔR of the sclera is ensured. 31 The meridian transition zone curve of the anterior surface of the sclera is calculated.

[0048] Furthermore, in the above method, based on the designed optical zone of the scleral lens, the transition zone of the posterior surface of the scleral lens and the transition zone of the anterior surface of the scleral lens are designed, including:

[0049] Take a chord of horizontal length chord4, intersecting the anterior surface curve of the sclera at two points P on the left and right. landing_l And Planding_r; point P on the posterior surface of the sclera. sc_l Point Psc_r represents the edge of the optical zone on the posterior surface of the scleral lens. landing_l To point P sc_l Section and point P landing_rTo point P sc_r The section, which is the transition area for scleral lenses, has the following chord4 values:

[0050] chord4 = WTW + ΔC1

[0051] Wherein, WTW is the white-to-white value of the eyeball, and ΔC1 is an empirical value greater than 0;

[0052] The vertical distance between the transition zone of the posterior surface of the sclera and the anterior surface of the cornea and sclera is determined by P. sc_l Vertical distance d to the anterior surface of the cornea and sclera sc_l Decrease non-uniformly to 0 sequentially:

[0053]

[0054] y = y secler -d sc_l *coeff

[0055] Where index is the exponent;

[0056] y sc_l and x sc_l For P sc_l The coordinates;

[0057] y landing_l and x landing_l For P landing_l The coordinates;

[0058] pow(a,b) represents a raised to the power of b;

[0059] coeff is any line segment P sc_l Point P landing_l The vertical gap between the posterior surface of the sclera and the anterior surface of the cornea and sclera at any x point relative to d sc_l The proportionality coefficient;

[0060] y secler Let x be the vertical coordinate on the anterior surface of the sclera at any x.

[0061] y and x are from point P sc_l Point P landing_l The coordinates of any point in the transition region;

[0062] Based on the curve of the transition zone on the posterior surface of the sclera, the thickness ΔR of the sclera is ensured. 31 The meridian transition zone curve of the anterior surface of the sclera is calculated.

[0063] Furthermore, in the above method, based on the designed transition zone of the scleral lens, the landing zones of the posterior and anterior surfaces of the scleral lens are designed, including:

[0064] Based on the diameter D of the scleral lens seleraLen This allows us to determine the P-terminus of the posterior surface meridian of the scleral lens. end_l and P end_r ;

[0065] P at the posterior surface meridian of the scleral lens end_l and P end_r A pre-defined gap d is designed between the anterior surface of the cornea and sclera. end From point P end_l To P landing_l , and from P end_r To P landing_r The landing zone of the posterior surface of the scleral lens is separated from the anterior surface of the sclera by a predetermined gap d. end Decrease to 0;

[0066] Assuming the scleral lens tip P end_l and P end_r The thickness at edgeScLenThick is based on the P at the end of the scleral lens. end_l and P end_r The thickness at edgeScLenThick is used to determine the landing zone on the anterior surface of the scleral lens.

[0067] Furthermore, in the above method, based on the designed transition zone of the scleral lens, the landing zones of the posterior and anterior surfaces of the scleral lens are designed, including:

[0068] Based on the diameter D of the scleral lens seleraLen This allows us to determine the P-terminus of the posterior surface meridian of the scleral lens. end_l and P end_r Select a reference point P from the transition zone. l_ref and P r_ref ;

[0069] Use three points P end_l P landing_l and P l_ref Define a radius R l If the arc is a circle, then arc P end_l P landing_l The left landing area; use three points P. end_r P landing_r and P r_ref Define a radius R r If the arc is a circle, then arc P end_r P landing_r This is the right-side landing area.

[0070] Compared with existing technologies, this invention is based on the topographic map of the anterior surface of the patient's cornea and sclera, dividing the anterior surface meridians of the cornea and sclera at equal angles, and designing the surface profile curves of the anterior and posterior surfaces of the scleral lens according to the morphology of the patient's cornea and sclera. Finally, the 3D surface profile data of the scleral lens is obtained through 3D reconstruction. Specifically, the optical zone of the scleral lens can be designed in various ways depending on the different shapes of the patient's eyeball; the transition zone can be designed in diverse ways to ensure the thickness of the intraocular fluid at certain locations based on the ocular surface morphology; and the landing zone smoothly conforms to the anterior surface of the sclera. This invention conforms to the patient's ocular surface morphology to the greatest extent, ensuring the uniformity of the intraocular fluid and the matching degree with the ocular surface, thereby achieving trial-free scleral lens fitting, improving clinical accuracy and efficiency, and enhancing patient safety and satisfaction. Attached Figure Description

[0071] Figure 1 This is a flowchart of a method for designing scleral lenses based on ocular surface and scleral topography according to an embodiment of the present invention;

[0072] Figure 2 This is a schematic diagram of the segmentation result of the anterior surface of the cornea and sclera in an OCT image according to an embodiment of the present invention;

[0073] Figure 3 This is a topographic map of the anterior surface sagittal of the sclera according to an embodiment of the present invention;

[0074] Figure 4 This is a schematic diagram of separating n meridians from a scleral topographic map, where n is 180 meridians, according to an embodiment of the present invention.

[0075] Figure 5 This is a schematic diagram of the shape of each meridian on the anterior surface of the sclera according to an embodiment of the present invention;

[0076] Figure 6a This is a schematic diagram of an embodiment of the present invention, which defines an optical region based on the entire meridian at a fixed angle.

[0077] Figure 6b This is a schematic diagram of an embodiment of the present invention, which defines an optical region based on a fixed chord length along the entire meridian.

[0078] Figure 7a This is a schematic diagram of an embodiment of the present invention, which defines an optical region based on a semi-meridian at a fixed angle.

[0079] Figure 7b This is a schematic diagram of an embodiment of the present invention, which defines an optical region based on a semi-meridian with a fixed chord length.

[0080] Figure 8 This is a schematic diagram of the transition zone design according to an embodiment of the present invention;

[0081] Figure 9aThis is a schematic diagram of a simplified landing area design according to an embodiment of the present invention;

[0082] Figure 9b This is a schematic diagram of the arc-shaped landing area design according to an embodiment of the present invention;

[0083] Figure 10 This is a schematic diagram of the smoothing process of the front and rear surface curves of a scleral lens according to an embodiment of the present invention. Detailed Implementation

[0084] The present invention will now be described in further detail with reference to the accompanying drawings.

[0085] In a typical configuration of this application, the terminal, the device of the service network, and the trusted party all include one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0086] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0087] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include non-transitory computer-readable media, such as modulated data signals and carrier waves.

[0088] like Figures 1 to 10 As shown, the present invention provides a method for designing scleral lenses based on ocular surface scleral topography, including the following steps S1, S2, S3, S4, S5, S6, S7 and S8.

[0089] Step S1 includes: acquiring OCT images of the subject's eyeballs using an OCT device.

[0090] Step S2 includes: obtaining the anterior surface curve of the cornea and sclera in the ocular OCT image, such as... Figure 2 As shown; 3D reconstruction of the anterior surface curve of the sclera at the corneal fossa is performed to obtain a scleral topography map, as shown. Figure 3 As shown.

[0091] Preferably, during the acquisition of scleral topography, the radius of curvature R1 of the best-fit sphere and the center of the best-fit sphere can be obtained. Specifically, the radius of curvature R1 of the best-fit sphere and... Figure 6a , 6b The R1 in 7a and 7b is the same, and the center of the best-fit sphere of the cornea is the same as that in 7a and 7b. Figure 6a , 6b The center in 7a and 7b is the same.

[0092] Step S3 includes: circumferentially cutting n meridians from the scleral topography map, where n is any positive integer.

[0093] like Figure 4 As shown, generally, n = 180, meaning a meridian is taken every 1°. A schematic diagram of the shape of each meridian on the anterior surface of the cornea and sclera is shown below. Figure 5 As shown.

[0094] Step S4 includes: designing the optical zone of the sclera based on each meridian to obtain the optical zone curves of the front and rear surfaces of the sclera.

[0095] Alternatively, the optical zone can be divided based on the entire meridian, which can be done in two ways.

[0096] The first method is based on determining the optical region using a fixed included angle: such as... Figure 6a As shown, a first chord with a horizontal length of chord1 can be taken (this chord length is generally 6mm-9mm based on the pupil diameter). The first chord intersects the entire meridian of the anterior surface curve of the cornea at two points. The angles between the line connecting these two points and the center of the best-fit sphere of the cornea and the y-axis are α and β, respectively. Since the anterior surface of the sclera is not necessarily perfectly symmetrical about the y-axis, α and β are not necessarily equal, but the difference is not significant. That is, the optical regions of the designed posterior and anterior surfaces of the sclera are fan-shaped regions of α+β. Then, the chord lengths chord2 and chord3 of the designed posterior surface region of the sclera can be calculated. Based on the chord lengths chord1, chord2, and chord3, the range of the optical region can be determined. The lengths of chord1, chord2, and chord3 are calculated as follows:

[0097] chord1:chord2:chord3=R1:R2:R3

[0098] More preferably, in terms of the design of the radius of curvature of the optical zone:

[0099] To better adapt to different corneal anterior surface shapes, the optical zone is designed with a spherical shape. For example... Figure 6a As shown, R1 is the radius of curvature of the best-fit corneal sphere obtained from the scleral topography map in step 2, R2 is the radius of curvature of the designed posterior surface of the scleral lens, and R3 is the radius of curvature of the designed anterior surface of the scleral lens. R1, R2, and R3 have the following relationship:

[0100] R2-R1=ΔR 21 ;

[0101] R3-R2=ΔR 31 ;

[0102] Where, ΔR 21 The thickness reserved for the microscopic fluid is an empirical value (100-350 micrometers), which can also be adjusted according to the patient's ocular surface information; ΔR 31 To design the central thickness of scleral lenses, sclLenThick (100-500 micrometers).

[0103] The second method is based on determining the optical region using a fixed chord length: such as... Figure 6b As shown, a horizontal chord of length chord1 is taken based on the pupil diameter. The chord lengths chord2 and chord3 of the posterior surface region of the designed scleral lens are both equal to chord1. Thus, the range of the optical zone along the entire meridian can be determined based on the chord lengths chord1, chord2, and chord3.

[0104] Alternatively, the optical zone can be defined based on a semi-meridian, which can be done in two ways:

[0105] The first method is based on determining the optical region using a fixed included angle: such as... Figure 7a As shown, when truncating the anterior surface curve of the sclera in step 2, it is done using a semi-meridian method, resulting in 2*n semi-meridians. For example, n = 180. A second chord with a horizontal length of chord1 / 2 can be taken based on the pupil diameter. This second chord intersects the anterior surface of the sclera's semi-meridian at a point. The angle between the line connecting this point and the center of the best-fit sphere of the cornea and the y-axis is α. Therefore, the optical regions of the posterior and anterior surfaces of the sclera lens designed based on the semi-meridian are fan-shaped regions of α. The chord lengths chord2 and chord3 of the designed posterior and anterior surfaces of the sclera lens can then be calculated. Based on these chord lengths, the range of the optical region of the semi-meridian can be determined. The lengths of chord1, chord2, and chord3 are calculated as follows:

[0106] chord1:chord2:chord3=R1:R2:R3.

[0107] The second method is based on determining the optical region using a fixed chord length: such as... Figure 7b As shown, similarly, when truncating the anterior surface curve of the sclera in step 2, it is truncated using a semi-meridian method, resulting in 2*n semi-meridians, for example, n = 180. A horizontal chord of length chord1 / 2 is taken based on the pupil diameter. The chord lengths chord2 / 2 and chord3 / 2 of the posterior surface region of the designed scleral lens are both equal to chord1 / 2. Based on the chord lengths chord1, chord2, and chord3, the optical range of the semi-meridian can be determined.

[0108] Specifically, when the patient has an abnormal cornea, such as keratoconus with the corneal apex deviating significantly from the y-axis, only a method based on dividing the optical zone along a semimeridian can be used. However, when the patient has a normal cornea, both methods based on the entire meridian and those based on a semimeridian are acceptable.

[0109] Step S5 includes: based on the designed optical zone of the sclera, designing the transition zone of the posterior surface of the sclera and the transition zone of the anterior surface of the sclera, and obtaining the transition zone curves of the anterior and posterior surfaces of the sclera.

[0110] Based on the optical zone of the sclera lens obtained in step 4, the transition region of the sclera lens is designed, such as... Figure 8 As shown, a chord of horizontal length chord4 can be taken, intersecting the anterior scleral surface curve at two points P on the left and right. landing_l Points P and Planding_r are the landing points of the scleral lens. Point P on the posterior surface of the scleral lens... sc_l Point Psc_r represents the edge of the optical zone on the posterior surface of the scleral lens. landing_l To point P sc_l Section and point P landing_r To point P sc_r The segment refers to the transition area for scleral lenses. The chord4 values ​​are as follows:

[0111] chord4 = WTW + ΔC1

[0112] Among them, WTW is the white-to-white value of the eyeball, and ΔC1 is an empirical value greater than 0 (100-300 micrometers).

[0113] The design methods for optical zones based on the entire meridian and those based on a half meridian are the same; here, we will take the entire meridian as an example.

[0114] Ideally, taking the left side as an example, Figure 8In step S51, the design of the transition zone on the posterior surface of the scleral lens includes:

[0115] Point P on the left edge of the optical zone of the posterior surface meridian of the sclera lens sc_l The vertical distance to the anterior surface of the cornea and sclera is d. sc_l The design of the posterior surface transition zone of scleral lenses can include the following four methods:

[0116] Method 1: From point P sc_l (x sc_l ,y sc_l ) to point P landing_l (x landing_l ,y landing_l The transition region is linearly transitioned:

[0117]

[0118] k slop =(y sc_l -y landing_l ) / (x sc_l -x landing_l )

[0119] y = y sc_l +k slop *(xx sc_l )

[0120] Among them, y sc_l and x sc_l For P sc_l The coordinates;

[0121] y landing_l and x landing_l For P landing_l The coordinates;

[0122] k slop Let P be the line segment sc_l Point P landing_l The slope;

[0123] y and x are from point P sc_l Point P landing_l The coordinates of any point in the transition region.

[0124] Method 2: The vertical distance from the posterior surface transition zone of the scleral lens to the anterior surface of the cornea and sclera is determined by P. sc_l Vertical distance d to the anterior surface of the cornea and sclera sc_l Decrease gradually and evenly to 0:

[0125] d = d sc_l / (x sc_l -x landing_l )*(xx sc_l )

[0126] y = y secler -d sc_l

[0127] Among them, y sc_l and x sc_l For P sc_l The coordinates;

[0128] y landing_l and x landing_l For P landing_l The coordinates;

[0129] d is line segment P sc_l Point P landing_l The vertical gap between the posterior surface of the sclera and the anterior surface of the cornea and sclera at any x point;

[0130] y secler Let x be the vertical coordinate on the anterior surface of the sclera at any x.

[0131] y and x are from point P sc_l Point P landing_l The coordinates of any point in the transition region.

[0132] Method 3: The vertical distance between the transition zone of the posterior surface of the scleral lens and the anterior surface of the cornea and sclera is determined by P. sc_l Vertical distance d to the anterior surface of the cornea and sclera sc_l Decrease non-uniformly to 0 sequentially:

[0133]

[0134] y = y secler -d sc_l *coeff

[0135] Where index is the exponent, which is generally [2, 8];

[0136] y sc_l and x sc_l For P sc_l The coordinates;

[0137] y landing_l and x landing_l For P landing_l The coordinates;

[0138] pow(a,b) represents a raised to the power of b;

[0139] coeff is any line segment P sc_l Point P landing_l The vertical gap between the posterior surface of the sclera and the anterior surface of the cornea and sclera at any x point relative to d sc_l The proportionality coefficient;

[0140] ysecler Let x be the vertical coordinate on the anterior surface of the sclera at any x.

[0141] y and x are from point P sc_l Point P landing_l The coordinates of any point in the transition region.

[0142] Method 4: Designed based on specific clinical needs:

[0143] If a clinical patient has a disease on a certain part of the ocular surface, a certain thickness (d) needs to be maintained at that location when wearing scleral lenses. i_l The storage space for the nursing solution can be divided into sections, such as... Figure 8 P, a point on the left limbus i_l The transition zone is divided into P sc_l -P i_l , and P i_l -P landing_l Two segments are given, and k (k>2) B-spline interpolations are performed on the transition region between the two segments.

[0144] If there are multiple clinical diagnoses that require storage space for nursing solutions, simply mark all the points and then perform k (k>2) B-spline interpolation cycles.

[0145] Specifically, the design method for the transition area on the right side of the posterior surface meridian of the scleral lens is the same as that on the left side.

[0146] Step S52, design of the anterior surface transition zone of the scleral lens, including:

[0147] Based on the curve of the meridional transition zone on the posterior surface of the sclera, calculated in step S51, the thickness ΔR of the sclera is ensured. 31 This allows for the calculation of the meridian transition zone curve on the anterior surface of the sclera.

[0148] Step S6 includes: based on the designed transition zone of the scleral lens, designing the landing zone of the posterior surface and the landing zone of the anterior surface of the scleral lens, and obtaining the landing zone curves of the anterior and posterior surfaces of the scleral lens:

[0149] The appropriate diameter D of the scleral lens can be determined based on the patient's WTW (weight-to-weight ratio) of the eyeball. seleraLen :

[0150] D seleraLen =WTW+ΔD

[0151] Among them, WTW is the white-to-white value of the eyeball, and ΔD is an empirical value (300-600 micrometers);

[0152] Based on the diameter D of the scleral lens seleraLen This allows us to determine the P-terminus of the posterior surface meridian of the scleral lens. end_l and P end_r .

[0153] Step S61 includes Method 1: Simplified Design, specifically including steps S611 and S612.

[0154] Step S611 includes the design of the landing zone on the posterior surface of the scleral lens: such as Figure 9a As shown, the posterior surface meridian end P of the scleral lens end_l and P end_r A small pre-set gap d is designed with the anterior surface of the cornea and sclera. end From point P end_l To P landing_l , and from P end_r To P landing_r The landing zone of the posterior surface of the scleral lens is separated from the anterior surface of the sclera by a predetermined gap d. end Decrease to 0;

[0155] Step S612 includes the design of the landing zone on the anterior surface of the scleral lens: such as Figure 9a As shown, assuming the scleral lens tip P end_l and P end_r The thickness is edgeScLenThick. To ensure that edgeScLenThick is neither too thick, causing a significant foreign body sensation for the patient, nor too thin, resulting in insufficient scleral lens strength, the value of edgeScLenThick is set as follows:

[0156] edgeScLenThick=c*sclLenThick,c∈(0.3,0.7)

[0157] Wherein, sclLenThick is the central thickness of the scleral lens;

[0158] Based on the scleral lens end P end_l and P end_r The thickness at edgeScLenThick is used to determine the landing zone on the anterior surface of the scleral lens;

[0159] Step S62 is Method 2: Arc Design, which specifically includes steps S621 and S622.

[0160] Step S621, design of the landing area on the posterior surface of the scleral lens, such as... Figure 9b As shown, point P in Method 1 is used. end_l and P end_r With P landing_l and P landing_r Additionally, a suitable reference point P needs to be selected from the transition zone. l_ref and P r_ref Use three points P end_l P landing_l and P l_ref Define a radius Rl If the arc is a circle, then arc P end_l P landing_l The left landing area; use three points P. end_r P landing_r and P r_ref Define a radius R r If the arc is a circle, then arc P end_r P landing_r This is the right-side landing area.

[0161] Step S622, the design of the landing area on the anterior surface of the scleral lens, is similar to that of Method 1.

[0162] Step S7 includes: smoothing the anterior and posterior surface curves of the sclera lens at the junctions of each partition to obtain the anterior and posterior surface curves of the sclera lens calculated according to pixel resolution.

[0163] like Figure 9a and 9b As shown, the anterior and posterior surface curves of the scleral lens are not smooth at the junctions of various sections, i.e., there are continuous non-differentiable points. Taking these continuous non-differentiable points as centers, a section L of the curve on both sides is taken and smoothed or fitted, such as mean smoothing, Gaussian smoothing, Bézier curve fitting, polynomial fitting, etc., to process the anterior and posterior surfaces of the scleral lens into smooth curves. The result is as follows. Figure 10 As shown.

[0164] Step S8 includes: the anterior and posterior surface curves of the sclera obtained in step 7 are calculated at pixel resolution and need to be converted to polar coordinates. Then, the data is densified as needed (e.g., linear interpolation). The densified data is then reconstructed in three dimensions to obtain personalized sclera 3D point cloud data.

[0165] In summary, this invention is based on the topographic map of the anterior surface of the patient's cornea and sclera, dividing the anterior surface meridians of the cornea and sclera at equal angles, and designing the surface profile curves of the anterior and posterior surfaces of the scleral lens according to the morphology of the patient's cornea and sclera. Finally, 3D reconstruction is used to obtain the 3D surface profile data of the scleral lens. Specifically, the optical zone of the scleral lens can be designed in various ways depending on the different shapes of the patient's eyeball; the transition zone can be designed in diverse ways to ensure the thickness of the intraocular fluid at certain locations based on the ocular surface morphology; and the landing zone smoothly conforms to the anterior surface of the sclera. This invention conforms to the patient's ocular surface morphology to the greatest extent, ensuring the uniformity of the intraocular fluid and the matching degree with the ocular surface, thereby achieving trial-free scleral lens fitting, improving clinical accuracy and efficiency, and enhancing patient safety and satisfaction.

[0166] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

[0167] It should be noted that the present invention can be implemented in software and / or a combination of software and hardware, for example, using an application-specific integrated circuit (ASIC), a general-purpose computer, or any other similar hardware device. In one embodiment, the software program of the present invention can be executed by a processor to implement the steps or functions described above. Similarly, the software program of the present invention (including associated data structures) can be stored in a computer-readable recording medium, such as RAM memory, a magnetic or optical drive, a floppy disk, or similar devices. Furthermore, some steps or functions of the present invention can be implemented in hardware, for example, as circuitry that works with a processor to perform the various steps or functions.

[0168] Furthermore, a portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. The program instructions invoking the methods of the invention may be stored in a fixed or removable recording medium, and / or transmitted via a data stream in a broadcast or other signal-carrying medium, and / or stored in the working memory of a computer device operating according to the program instructions. Here, an embodiment of the invention includes an apparatus comprising a memory for storing computer program instructions and a processor for executing the program instructions, wherein, when the computer program instructions are executed by the processor, the apparatus is triggered to operate the methods and / or technical solutions based on the foregoing embodiments of the invention.

[0169] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be embraced within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims. Furthermore, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices recited in the apparatus claims may also be implemented by a single unit or device in software or hardware. The terms "first," "second," etc., are used to indicate names and do not indicate any particular order.

Claims

1. A method for designing scleral lenses based on ocular surface scleral topography, characterized in that, include: Obtain the anterior surface curve of the cornea and sclera in the OCT image of the eyeball, and perform 3D reconstruction of the anterior surface curve of the cornea and sclera to obtain the scleral topography map. Meridians are extracted circumferentially from the scleral topography map; based on each meridian, the optical zone of the scleral lens is designed to obtain the optical zone curves of the front and rear surfaces of the scleral lens; Based on the designed optical zone of the sclera, the transition zone of the posterior surface and the transition zone of the anterior surface of the sclera are designed to obtain the transition zone curves of the anterior and posterior surfaces of the sclera. Based on the designed transition zone of the scleral lens, the landing zones of the posterior and anterior surfaces of the scleral lens are designed to obtain the landing zone curves of the anterior and posterior surfaces of the scleral lens. The curves of the optical zone, transition zone and landing zone of the front and rear surfaces of the sclera are smoothed at the junctions of each zone to obtain the front surface curve and rear surface curve of the sclera calculated in pixel resolution. After converting the anterior and posterior surface curves of the sclera to a polar coordinate system, the data is densified to obtain densified data. The densified data is then used for three-dimensional reconstruction to obtain the corresponding 3D point cloud data of the sclera. The optical zone design of the scleral lens is based on each meridian, including: Based on the pupil diameter, a first chord of horizontal length chord1 is taken. The first chord intersects the entire meridian of the anterior surface curve of the cornea at two points. The angles between the line connecting these two points and the center of the best-fit sphere of the cornea obtained from the scleral topography and the y-axis are α and β, respectively. Based on the optical regions α+β of the posterior and anterior surfaces of the sclera, the chord length chord2 of the posterior surface region of the sclera and the chord length chord3 of the anterior surface region of the sclera are calculated. Based on chord lengths chord1, chord2, and chord3, the range of the optical zone along the entire meridian is determined; Alternatively, the optical zone design of the scleral lens can be based on each meridian, including: Based on the pupil diameter, take a second chord with a horizontal length of chord1 / 2. The second chord intersects the anterior surface of the sclera at a point on the semimeridian. The angle between the line connecting this point and the center of the best-fit sphere of the cornea and the y-axis is α. Based on the semi-meridian, the optical regions α of the posterior and anterior surfaces of the sclera are designed, and the chord lengths chord2 and chord3 of the posterior and anterior surfaces of the sclera are calculated. Based on chord lengths chord1, chord2, and chord3, the range of the optical zone of the semimeridian is determined.

2. The method for designing scleral lenses based on ocular surface scleral topography as described in claim 1, characterized in that, Based on chord lengths chord1, chord2, and chord3, the extent of the optical zone along the entire meridian or half-meridian is determined, including: The lengths of chord1, chord2, and chord3 are calculated as follows: chord1:chord2:chord3=R1:R2:R3, R1 is the radius of curvature of the best-fit sphere of the cornea obtained from the scleral topography; R2 is the radius of curvature of the posterior surface of the scleral lens; R3 is the radius of curvature of the anterior surface of the scleral lens; R1, R2, and R3 have the following relationship: R2-R1=ΔR 21 ; R3-R2=ΔR 31 ; Where, ΔR 21 Allow for thickness of the liquid under the microscope; ΔR 31 sclLenThick is the central thickness of the scleral lens.

3. The method for designing scleral lenses based on ocular surface scleral topography as described in claim 1, characterized in that, The optical zone design of the scleral lens is based on each meridian, including: Based on the pupil diameter, take a horizontal chord of length chord1. Make the chord lengths chord2 and chord3 of the posterior surface area of ​​the designed scleral lens equal to chord1. Based on the chord lengths chord1, chord2, and chord3, determine the range of the optical zone of the entire meridian.

4. The method for designing scleral lenses based on ocular surface scleral topography as described in claim 1, characterized in that, The optical zone design of the scleral lens is based on each meridian, including: Based on the pupil diameter, take a horizontal chord with a length of chord1 / 2. Make the chord lengths of the posterior surface region of the scleral lens, chord2 / 2 and the anterior surface region of the designed scleral lens, chord3 / 2, equal to chord1 / 2. Based on the chord lengths chord1, chord2, and chord3, determine the range of the optical zone of the semimeridian.

5. The method for designing scleral lenses based on ocular surface scleral topography as described in claim 2, characterized in that, Based on the designed optical zone of the scleral lens, the transition zones of the posterior and anterior surfaces of the scleral lens are designed, including: Take a chord of horizontal length chord4, intersecting the anterior surface curve of the sclera at two points P on the left and right. landing_l and P landing_r P on the posterior surface of the sclera lens sc_l and point P sc_r Point P is located at the edge of the optical zone on the posterior surface of the scleral lens. landing_l To point P sc_l Section and point P landing_r To point P sc_r The section, which is the transition area for scleral lenses, has the following chord4 values: chord4 = WTW + ΔC1 Wherein, WTW is the white-to-white value of the eyeball, and ΔC1 is an empirical value greater than 0; The vertical distance between the transition zone of the posterior surface of the sclera and the anterior surface of the cornea and sclera is determined by P. sc_l Vertical distance d to the anterior surface of the cornea and sclera sc_l Decrease gradually and evenly to 0: d=d sc_l / (x sc_l -x landing_l )*(x-x sc_l ) y=y secler -d sc_l Among them, y sc_l and x sc_l For P sc_l The coordinates; y landing_l and x landing_l For P landing_l The coordinates; d is line segment P sc_l Point P landing_l The vertical gap between the posterior surface of the sclera and the anterior surface of the cornea and sclera at any x point; y secler Let x be the vertical coordinate on the anterior surface of the sclera at any x. y and x are from point P sc_l Point P landing_l The coordinates of any point in the transition region; Based on the curve of the transition zone on the posterior surface of the sclera, the thickness ΔR of the sclera is ensured. 31 The meridian transition zone curve of the anterior surface of the sclera is calculated.

6. The method for designing scleral lenses based on ocular surface scleral topography as described in claim 2, characterized in that, Based on the designed optical zone of the scleral lens, the transition zones of the posterior and anterior surfaces of the scleral lens are designed, including: Take a chord of horizontal length chord4, intersecting the anterior surface curve of the sclera at two points P on the left and right. landing_l and P landing_r P on the posterior surface of the sclera lens sc_l and point P sc_r Point P is located at the edge of the optical zone on the posterior surface of the scleral lens. landing_l To point P sc_l Section and point P landing_r To point P sc_r The section, which is the transition area for scleral lenses, has the following chord4 values: chord4 = WTW + ΔC1 Wherein, WTW is the white-to-white value of the eyeball, and ΔC1 is an empirical value greater than 0; The vertical distance between the transition zone of the posterior surface of the sclera and the anterior surface of the cornea and sclera is determined by P. sc_l Vertical distance d to the anterior surface of the cornea and sclera sc_l Decrease non-uniformly to 0 sequentially: y=y secler -d sc_l *coeff Where index is the exponent; y sc_l and x sc_l For P sc_l The coordinates; y landing_l and x landing_l For P landing_l The coordinates; pow(a,b) represents a raised to the power of b; coeff is any line segment P sc_l Point P landing_l The vertical gap between the posterior surface of the sclera and the anterior surface of the cornea and sclera at any x point relative to d sc_l The proportionality coefficient; y secler Let x be the vertical coordinate on the anterior surface of the sclera at any x. y and x are from point P sc_l Point P landing_l The coordinates of any point in the transition region; Based on the curve of the transition zone on the posterior surface of the sclera, the thickness ΔR of the sclera is ensured. 31 The meridian transition zone curve of the anterior surface of the sclera is calculated.

7. The method for designing scleral lenses based on ocular surface and scleral topography as described in claim 6, characterized in that, Based on the designed transition zone of the scleral lens, the landing zones of the posterior and anterior surfaces of the scleral lens are designed, including: Based on the diameter D of the scleral lens seleraLen This allows us to determine the P-terminus of the posterior surface meridian of the scleral lens. end_l and P end_r ; P at the posterior surface meridian of the scleral lens end_l and P end_r A pre-defined gap d is designed between the anterior surface of the cornea and sclera. end From point P end_l To P landing_l , and from P end_r To P landing_r The landing zone of the posterior surface of the scleral lens is separated from the anterior surface of the sclera by a predetermined gap d. end Decrease to 0; Assuming the scleral lens tip P end_l and P end_r The thickness at edgeScLenThick is based on the P at the end of the scleral lens. end_l and P end_r The thickness is edgeScLenThick, which determines the landing zone on the anterior surface of the scleral lens.

8. The method for designing scleral lenses based on ocular surface and scleral topography as described in claim 6, characterized in that, Based on the designed transition zone of the scleral lens, the landing zones of the posterior and anterior surfaces of the scleral lens are designed, including: Based on the diameter D of the scleral lens seleraLen Determine the P-terminus of the posterior surface meridian of the scleral lens. end_l and P end_r Select a reference point P from the transition zone. l_ref and P r_ref ; Use three points P end_l P landing_l and P l_ref Define a radius R l If the arc is a circle, then arc P end_l P landing_l The left landing area; use three points P. end_r P landing_r and P r_ref Define a radius R r If the arc is a circle, then arc P end_r P landing_r This is the right-side landing area.

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