Method for evaluating performance of progressive refractive power lens
By determining astigmatism distribution data and applying weights based on aberration axes, the method corrects for vision clarity differences in progressive addition lenses, providing a more accurate performance evaluation.
Patent Information
- Application Number
- JP2024093469
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-06-10
- Publication Date
- 2025-12-22
AI Technical Summary
Existing methods for evaluating progressive addition lenses do not accurately reflect the differences in vision clarity due to varying aberration axes, leading to inaccurate performance assessments.
A method that determines astigmatism distribution data by measuring or simulating evaluation points on the lens surface, assigning weights based on the axial direction of aberration components to correct astigmatism data, and evaluating lens performance based on the corrected distribution.
The method provides a realistic evaluation of progressive addition lens performance by reflecting actual vision clarity differences, enabling more accurate assessments.
Smart Images
Figure 2025185315000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a method for evaluating the performance of a progressive-power lens, which obtains an astigmatism distribution based on astigmatism data obtained by measuring or simulating evaluation points distributed on the lens surface of the progressive-power lens, and evaluates the performance of the progressive-power lens based on the astigmatism distribution. [Background technology]
[0002] Progressive addition lenses are designed to connect the distance and near vision zones via a progressive zone, resulting in significant astigmatism on the lens surface. Astigmatism is a component equivalent to astigmatism imparted to the eye by external factors; in other words, the astigmatism component is nothing but astigmatism. Unlike the astigmatism power imparted to the eye by external factors, the astigmatism component of progressive addition lenses does not have a specific axis (astigmatism axis) in a specific direction; instead, it is variable and can have any of the following axes (i.e., astigmatism axis): straight astigmatism, against-the-rule astigmatism, and oblique astigmatism. Progressive addition lenses are generally measured for their lens surface characteristics using a lens mapper, a power distribution measuring device. Based on the measurement results, an astigmatism distribution map is created to evaluate the performance of the progressive addition lens. [Prior art documents] [Patent documents]
[0003] [Non-Patent Document 1] Author: Hidenaga Kobashi, Kazutaka Kamiya, Kimiya Shimizu, Takushi Kawamorita, Hiroshi Uozato, Paper title: "Effect of axis orientation on visual performance in astigmatic eyes", Publication name: "Journal of Cataract & Refract Surgery", Published June 22, 2012, Volume 38, Issue 8, P.1352~1359 [Non-patent document 2] FW Campbell, JJ Kulikowski, J. Levinson, Paper title: "The effect of orientation on the visual resolution of gratings", Publication name: "The Journal of Physiology", Published November 1, 1966, Volume 187, Issue 2, P.427~436 Summary of the Invention [Problem to be solved by the invention]
[0004] When the astigmatism of a progressive-addition lens is measured using a lens mapper, the difference in the axis of the aberration is not reflected in the measured value at each mapping point, which is the evaluation point of the power distribution measuring device. However, clinical findings have shown that even with the same amount of astigmatism, for example, between aberration on the parallel axis and aberration on the oblique axis (rectilinear astigmatism and oblique astigmatism when astigmatism is considered as astigmatism), aberration on the parallel axis results in better vision. In other words, with progressive power lenses, differences in the axial direction of the aberration result in differences in ease of vision (reduction of blur) that do not appear in measurements. Non-Patent Document 1 is a prior art document that mentions that the wearer's sense of blur differs depending on the axis direction even with the same amount of astigmatism. Non-Patent Document 1 describes the visual characteristics of lenses with astigmatism as follows: No aberration >> Parallel axis aberration = Vertical axis aberration >> Oblique axis aberration Furthermore, Patent Document 2 discloses that the visual characteristics for an axis change sinusoidally. "Varying sinusoidally" means that the visibility (reduction of blur) at a mapping point changes continuously depending on the phase of the aberration axis. Although the ease of vision (blurring) differs depending on the axis of aberration, this has not previously been reflected in astigmatism distribution maps based on values measured with Lens Mapper, and the analysis results of astigmatism distribution maps do not necessarily match the actual vision of progressive addition lenses. Therefore, there has been a demand for a means to determine the lens performance of progressive addition lenses that takes into account the difference in vision due to differences in the axis of aberration. [Means for solving the problem]
[0005] In order to solve the above problem, Means 1 is a performance evaluation method for a progressive-power lens, which determines astigmatism distribution data based on astigmatism data obtained by measuring or simulating evaluation points distributed on the lens surface of the progressive-power lens, and evaluates the performance of the progressive-power lens based on the astigmatism distribution data, and for the axial direction of the aberration component at the evaluation point, which has an angle in the range of 0 to 180 degrees, a weight for ease or difficulty of vision is set for each evaluation point according to the axial direction of the aberration component, the astigmatism data is corrected to reflect the weight, and the performance of the progressive-power lens is evaluated based on the distribution state of the astigmatism data after the correction. This allows the astigmatism distribution to be analyzed based on astigmatism data in which the weight of visibility or difficulty is assigned to each evaluation point as a correction value, thereby reflecting the actual visibility of progressive power lenses and enabling lens performance evaluation that is in line with reality.
[0006] "Astigmatism data" is data on at least the C power and astigmatism axis measured by the lens mapper. By weighting this data, corrected astigmatism data is obtained. The mapping points from which the lens mapper obtains astigmatism data are widely distributed on the lens surface, and if necessary, interpolation calculations can be performed between the mapping points to obtain astigmatism contours. The "axis of an aberration component" refers to three types of axes: the parallel axis, the vertical axis, and the oblique axis. Astigmatism is equivalent to the astigmatism component, as mentioned above. Therefore, among the axes of the aberration components, the parallel axis is the axis of straight astigmatism, the vertical axis is the axis of reverse astigmatism, and the oblique axis is the axis of oblique astigmatism. The parallel axis is in the 0-degree or 180-degree direction, the vertical axis is in the 90-degree direction, and the oblique axis is any other direction. In other words, it is assumed that the oblique axis may be in a direction other than 45 degrees or 135 degrees. For example, it is advisable to distinguish and weight aberrations in the oblique axis direction from aberrations in other directions. "Reflecting weights" means, for example, that multiplying the weight by the original value is common and easy to calculate, but weights can also be reflected using any of the four arithmetic operations of addition, subtraction, multiplication, and division. Furthermore, weights can also be applied using nonlinear weights other than the four arithmetic operations, or exponential weights. Exponential functions are also included as part of nonlinear weights.
[0007] The phrase "weighting the visibility or invisibility of the mapping points by distinguishing between at least the aberration of the diagonal axis and the aberration of the other directional axes" means that when there is an aberration of the diagonal axis, it becomes significantly more difficult to see compared to when there is an aberration of the parallel or vertical axis. No aberration >> Parallel axis aberration = Vertical axis aberration >> Oblique axis aberration This tends to be the case. Therefore, when there is an aberration component, the oblique axis is the least visible, and the aberration of the parallel axis = the vertical axis is the most visible. Therefore, when weighting visibility, it is best to give the oblique axis the least weight and the aberration of the parallel axis and the vertical axis the most weight. When weighting visibility, the opposite method is used. Since the performance of the progressive power lens is evaluated based on the distribution of the astigmatism data after correction, it is not necessary for the astigmatism distribution map to be output. Of course, an operator may visually inspect the astigmatism distribution map to make a judgment, but the corrected astigmatism data may also be analyzed and judged by AI (artificial intelligence) instead of a human. Furthermore, the means 2 creates an astigmatism distribution map based on the astigmatism data of the mapping points, and evaluates the performance of the progressive-power lens based on the astigmatism distribution map. This allows the astigmatism distribution diagram to reflect the actual appearance of the progressive addition lens, so that an operator can easily evaluate the performance of the progressive addition lens by visual inspection. The astigmatism distribution diagram may be, for example, two-dimensional or three-dimensional. Although it is possible to analyze the astigmatism distribution without using an astigmatism distribution diagram, an astigmatism distribution diagram like this allows a person to easily make an intuitive judgment.
[0008] In addition, in means 3, the weight is set using the angle of the axis of the aberration component as a parameter, and is set to be maximum or minimum when the axial direction of the aberration component is 45 degrees or 135 degrees, and conversely to be minimum or maximum when the axial direction is 0 degrees or 90 degrees. As such, it is recommended to set the maximum and minimum weights at angles of 45 degrees or 135 degrees, and at angles of 0 degrees or 90 degrees. The function of visibility versus axial angle direction, specifically, shows the characteristics of a cosine curve, where a sine wave is shifted by π / 2 in radians, as shown in Figure 5. Figure 5 displays 180 degrees (π), which is the wavelength of a periodic function of a cosine curve with a period of 2π. Figure 5 also shows a schematic representation of the characteristics obtained based on the results of a visual characteristics test conducted on a set of subjects. The horizontal axis represents the axial angle of the aberration, and the vertical axis represents the number of waves per unit degree using spatial frequency as a measure of visibility. The values on the vertical axis represent the number of stripes per degree when the subject is shown a striped pattern. The 0 degree (180 degree) position represents the horizontal axis, the 90 degree (270 degree) position represents the vertical axis, and the 45 degree (135 degree) position represents the diagonal axis. Generally, as shown in Figure 5, when there is an aberration component, the characteristic is that the oblique axis is the least visible, and the aberration of the parallel axis = the vertical axis is the most visible. Therefore, when weighting visibility, it is best to give the diagonal axis the smallest weight, and the aberration of the parallel axis and the vertical axis the largest weight. When weighting visibility, the opposite method is used. It is possible to have the aberration of the parallel axis = the vertical axis, but it is also possible to weight either the aberration of the parallel axis or the vertical axis differently from the other. Furthermore, in the means 4, when the prescribed power of the wearer includes astigmatism power, correction processing is performed by subtracting the prescribed astigmatism power from the astigmatism distribution data of the progressive addition lens. If there is astigmatism caused by such astigmatic power as an external factor, it will affect the weight of the astigmatism based on the progressive characteristics, and will not become astigmatism based purely on the progressive characteristics but will become a kind of noise, so it is best to cancel this.
[0009] Furthermore, in means 5, a function f(AX) having the axial angle of the aberration component as a parameter is maximum or minimum when the axial angle of the aberration component is 0 degrees, 90 degrees or 180 degrees, and conversely is maximum or minimum when the axial angle of the aberration component is other than 0 degrees, 90 degrees or 180 degrees, and the astigmatism of the evaluation point after correction is obtained by applying the function f(AX) as the weight to the astigmatism of the evaluation point before correction. As a result, the astigmatism of the evaluation point after correction reflecting the weight is obtained. In the means 6, the function f(AX) having the axial angle of the aberration component as a parameter is expressed by the following equation or an equation equivalent to the following equation, with a, b, ω, and α as coefficients: This equation is a general formula for the function f(AX). a, b, and (ωAX + α) are determined so that the equation holds for any suitable weight (numerical value). The coefficient ω, which is multiplied by the axial angle, is generally a parameter that changes the angular phase as an angular frequency, but in the present invention, it is used to maximize (or minimize) the axial angle of astigmatism when it is 0 degrees or 180 degrees, and minimize (or maximize) other oblique axes. The coefficient α added to the axial angle is a parameter that determines the phase at the initial position of the sine wave, but in the present invention, it is a parameter that fine-tunes the peak position of the cosine curve (the peak position of visibility or difficulty). Since equivalent equations will yield the same solution, f(AX) may be expressed in other equivalent forms.
[0010]
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[0011] In addition, in the seventh means, the function f(AX) is expressed by the following formula or a formula equivalent to the following formula: This is a more specific expression of the general expression for function f(AX) in Means 6, and is an expression that assigns a weight that is maximum when the angle of the axial direction of the aberration component is 0° or 180° and minimum when the axial direction of the aberration component is 45° or 135°. In other words, it is an appropriate expression when assigning a weight using visibility as a measure. Since equivalent expressions will yield the same solution, f(AX) may be expressed in other equivalent forms.
[0012]
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[0013] In the eighth means, the function f(AX) is set to have a maximum or minimum value of 1.1 to 2.0. These are specific values that are appropriate for the weights, because if the weights are too large, they will not match the actual astigmatism of the progressive lens. A more suitable value is a maximum or minimum value of 1.5 to 1.8, taking into account the actual vision due to the difference in aberration of the parallel axis and the oblique axis. The maximum or minimum value is determined by the aberration of the parallel axis and the oblique axis according to the prescription. Figure 6 is a graph showing the difference in visual acuity (perception) between aberrations along the parallel axis and aberrations along the oblique axis, as disclosed in the above-mentioned Non-Patent Document 1. The horizontal axis represents astigmatism, and the vertical axis represents logarithmic visual acuity (logMAR value). The open bars represent aberrations along the parallel axis, and the filled bars represent aberrations along the oblique axis. The graph shows the average logarithmic visual acuity obtained by having multiple subjects visually view the optotype. In other words, when there is aberration along the parallel axis, vision is generally 0.1 to 0.25 better than when there is aberration along the oblique axis. In addition, it is known from the following paper, for example, that there is a linear correlation between the logarithmic visual acuity decline and the astigmatism power (astigmatism). "Tavazzi S, Vlasak N, Zeri F, title: "Effects of Lens-Induced Astigmatism at Near and Far Distances", published magazine: "Clinical Optometry", publication date: 6 May 2023, Volume 15, P.105-P.117" Therefore, for example, when considering 0.2, an intermediate value between 0.1 and 0.3, the astigmatism change rate corresponding to a logarithmic visual acuity of 0.2 is approximately 1.8. From this, the weight given to the astigmatism C of the mapping point before correction can be set to 1.8 as the maximum or minimum value, and the astigmatism C' of the mapping point after correction can be calculated as C' = 1.8C. Here, let's set a+bcos(4AX)=1.8 to find a and b. In this case, the solution is a=1.4 and b=-0.4, so a maximum weight of 1.8 and a minimum weight of 1.0 will be assigned. The weight will vary to some extent depending on the difference in visual acuity (how it appears); if the difference in visual acuity (how it appears) is 0.1, the weight will be around 1.1, and if the difference in visual acuity (how it appears) is 0.25, the weight will be around 2.0. [Effects of the Invention]
[0014] According to the present invention, the astigmatism distribution can be analyzed based on astigmatism data in which the weight of visibility or difficulty is assigned to each evaluation point as a correction value, thereby reflecting the actual visibility of a progressive power lens and enabling a realistic lens performance evaluation. [Brief explanation of the drawings]
[0015] [Figure 1] FIG. 2 is a block diagram illustrating a peripheral device for executing calculations in a performance evaluation method for an advance refractive power lens according to an embodiment of the present invention. [Figure 2] FIG. 1 is an explanatory diagram illustrating a measurement method using a power distribution measurement device (lens mapper), which is a peripheral device. [Figure 3] 10 is a flowchart illustrating a process for correcting measured astigmatism based on the direction of the aberration axis in the same embodiment. [Figure 4] (a) is an astigmatism distribution diagram for a certain progressive-power lens A in the same embodiment, created without considering the axial direction of the astigmatism aberration component in the conventional manner; (b) is an astigmatism distribution diagram for the same progressive-power lens A, created with weights given according to the axial direction of the astigmatism aberration component in consideration of the axial direction of the astigmatism aberration component in the conventional manner; (c) is an astigmatism distribution diagram for a certain progressive-power lens B in the same embodiment, created without considering the axial direction of the astigmatism aberration component in the conventional manner; (d) is an astigmatism distribution diagram for the same progressive-power lens B, created with weights given according to the axial direction of the astigmatism aberration component in consideration of ... the conventional manner. [Figure 5]A graph showing 180 degrees (π), which is the wavelength of a periodic function of a cosine curve, as a characteristic obtained based on the results of a visual characteristic test conducted on a certain number of subjects. [Figure 6] A graph showing the difference in visual acuity (appearance) between aberrations along the parallel axis and aberrations along the diagonal axis. DETAILED DESCRIPTION OF THE INVENTION
[0016] An example of a method for evaluating the performance of a progressive-power lens according to an embodiment of the present invention will now be described. First, a schematic configuration of an example of a peripheral device for evaluating the performance of a progressive-power lens according to an embodiment of the present invention will be described, with components not directly related to the present invention being omitted from the illustration. As shown in Fig. 1, a calculation computer 1 is connected to a monitor 2, a keyboard 3, and a power distribution measuring device (lens mapper) 4. In this embodiment, the keyboard 3 is used as an input means for inputting numerical values and causing the calculation computer 1 to execute processing. The output means may be a printer or other output means for transferring data to other devices in addition to the monitor 2. The input means may be a keyboard 3 or other means for inputting data transferred from other devices such as other computers or data storage devices connected to a LAN. The calculation computer 1 is electrically configured with a CPU (Central Processing Unit) and peripheral devices such as ROM and RAM. The CPU, in accordance with a calculation program stored in the ROM, calculates weights for each mapping point based on the data group acquired by the lens mapper 4 and executes calculations to correct the data at the mapping points. An astigmatism distribution diagram is then created based on the corrected mapping point data obtained and displayed on the monitor 2.
[0017] As shown in Figure 2, the lens mapper 4 includes a light source 10, a prism 11, a beam splitter 12, a screen 13, and a CCD camera 14 as an imaging means. Opposite the screen 13 is a lens (hereinafter referred to as a round lens) 15 in a state before being processed into a target shape to be measured. The round lens 15 is a transparent plastic body formed into a circular planar shape and exhibits a meniscus shape. In this embodiment, the convex surface (front surface) of the round lens 15 is a progressive refractive surface, and the concave surface (back surface) is a spherical surface with an appropriate curve. In this configuration, when measuring with the lens mapper 4, the light beam emitted from the light source 10 toward the prism 11 is redirected 90 degrees by the reflecting surface 11a and directed toward the round lens 15 placed on the table 16. The light then passes through the concave surface of the round lens 15, reaches the convex surface, and is reflected. The reflected light then passes through the concave surface again, and passes through the prism 11 again to reach the beam splitter 12. The beam splitter 12 has a large number of holes arranged in an orderly manner at equal intervals vertically and horizontally, and the light beams (beams) that pass through the holes are projected onto the screen 55. These projected light points are called mapping points. The CCD camera 14 captures images of the mapping points projected on the screen 12.
[0018] The calculation computer 1 calculates the refractive power for all mapping points based on the positional displacement of the through holes corresponding to the light beams captured by the CCD camera 14. In other words, prescription data (data related to refractive power such as S power data, C power data, astigmatism axis data, and prism amount data) for the test lens 5 can be obtained for all positions mapped on the lens. The prescription data is stored in a RAM (not shown) inside the calculation computer 1. Furthermore, the calculation computer 1 calculates weights using the C power data and astigmatism axis data as astigmatism data from the prescription data. The weight data is stored in a RAM (not shown) inside the calculation computer 1. The calculation computer 1 also applies the calculated weights to the astigmatism data at each mapping point, applies them to the corrected astigmatism data to calculate correction values, creates an astigmatism distribution chart based on the corrected astigmatism data, and displays it on the monitor 2. The corrected astigmatism data is stored in a RAM (not shown) inside the calculation computer 1.
[0019] Next, a specific example of the measurement point correction calculation that takes weights into consideration and is executed by the calculation computer 1 will be described. Equation 3 is an equation for canceling the astigmatic power while taking into account the axial direction when the subject has a prescription for astigmatic power, and for correcting the astigmatic power C of the mapping point on the lens surface while taking into account its weight. If the astigmatic power is not canceled, the calculation can be simply made as ΔC' = f(AX)C, but in this case, the astigmatic power is canceled, so the formula is as shown in Equation 3. Equation 4 is a formula for calculating the weight f(AX). In this embodiment, the visibility weight is set to a maximum of 1.8, and a weight of 1.8 is assigned if the axis at the mapping point is a horizontal axis or a vertical axis, and a weight of 1.0 is assigned if the axis is a diagonal axis. The calculation computer 1 calculates the corrected ΔC' at each mapping point based on equations 3 and 4.
[0020]
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[0021]
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[0022] Next, the process executed by the calculation computer 1 (CPU) to create an astigmatism distribution diagram will be described with reference to Fig. 3. The following routine is an example. (1) In step S1, the calculation computer 1 converts the prescribed power of the progressive power lens of the subject into Jackson's Cross Cylinder (JCC) notation for the astigmatism component and its astigmatism axis. 000 and J 045 The conversion formula is as shown in Formula 5. Next, in step S2, the calculation computer 1 calculates the weight f(AX0) for the astigmatic axis of the prescription power using Formula 4, and in step S3, calculates the weight J obtained by Formula 5. 000 and J 045 By giving weight f(AX0) to R, which is the parameter of Equation 3 000 and R 045 R 000 and R 045 The calculation formula is as shown in Equation 6. The calculation here is for determining the parameters for the astigmatic component of the prescription power to be cancelled, which is used in Equation 3.
[0023]
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[0024]
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[0025] (2) Next, in step S4, the calculation computer 1 converts each mapping point (49 x 49 points in this embodiment) obtained by the lens mapper 4 into JCC notation to obtain J0 and J 45 The conversion formula is as shown in Formula 7. Next, in step S5, the calculation computer 1 calculates the weight f(AX) for the astigmatic axis of the prescription power using Formula 4, and in step S6, calculates the weight f(AX) for the astigmatic axis of the prescription power using Formula 4. 45 By assigning a weight f(AX) to R, we can calculate R0, which is the parameter of the formula (3). 45 The calculation formula is as shown in Equation 8. (3) In step S7, the calculation computer 1 calculates R0 and R 000 and R 45 and R 045Applying this formula, the numerical values at each specific mapping point are input and calculated to obtain the corrected ΔC' for each mapping point. ΔC' is the value obtained by correcting C (amount of astigmatism) at each mapping point after canceling the astigmatic component of the prescription in consideration of the astigmatic axis. (4) The calculation computer 1 displays an astigmatism distribution map on the monitor 2 as a two-dimensional pseudocolor map and contour lines based on the corrected astigmatism value obtained for each mapping point using Equation 3.
[0026]
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[0027]
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[0028] Next, we will explain the comparison between the conventional method of calculating astigmatism for a prescription and creating an astigmatism distribution diagram that displays a two-dimensional pseudocolor map and contour lines, and the method of creating an astigmatism distribution diagram with the same prescription power but with astigmatism corrected as described above (i.e., corrected by ΔC'). Figure 4(a) is an astigmatism distribution diagram for a progressive-power lens A with certain progressive characteristics, created without considering the axial direction of the conventional astigmatism aberration component. On the other hand, Figure 4(b) is an astigmatism distribution diagram for the same progressive-power lens A, created by taking into account the axial direction of the astigmatism aberration component and assigning weights according to the axial direction. Figure 4(a) appears to show a good balance between the ear side and the nose side, but if the axial direction of the astigmatism aberration component is considered, as in Figure 4(b), it is clear that the lens is actually significantly out of balance between the ear side and the nose side. Also, Figure 4(c) is an astigmatism distribution diagram for a certain progressive-power lens B with progressive characteristics, created without considering the axial direction of the conventional astigmatism aberration component. On the other hand, Figure 4(d) is an astigmatism distribution diagram for the same progressive-power lens B, created with weights assigned according to the axial direction, taking into account the axial direction of the astigmatism aberration component. Figure 4(c) shows that there is a considerable imbalance between the ear side and the nose side, but if the axial direction of the astigmatism aberration component is considered, as in Figure 4(d), it can be seen that the characteristics of this progressive-power lens B are not actually that significantly unbalanced.
[0029] The present embodiment has the above-described configuration and thus provides the following effects. (1) The amount of aberration at the mapping points is corrected by using the difference in the axial appearance of the astigmatism aberration component, which was not apparent in the past, as a weight. This means that the astigmatism distribution map created using this method approaches the actual appearance, and the operator can visually check this corrected astigmatism distribution map and perform a more realistic performance evaluation. (2) When a progressive-power lens prescription includes astigmatism, its influence can be canceled out while taking into account the astigmatism axis, and the amount of aberration at the mapping point can be corrected. This makes it possible to evaluate the performance of progressive-power lenses that are not affected by astigmatism in the prescription. (3) The weight of 1.8 is set based on the difference in appearance between the parallel axis and the oblique axis. Therefore, the actual appearance is reflected in the correction value, and the obtained astigmatism distribution diagram represents the actual characteristics relatively well.
[0030] The above-described embodiment has been described merely as a specific embodiment for illustrating the principles and concepts of the present invention. In other words, the present invention is not limited to the above-described embodiment. The present invention can also be embodied in modified forms, for example, as follows. In the calculations of the above embodiment, the parameter of the weight f(AX) was determined so that the maximum weight would be 1.8 as shown in Equation 4, but the weight value can be changed as appropriate. Also, in the above, the weight was given by multiplying the aberration value of the original evaluation point, but it may also be given by other arithmetic operations, or a nonlinear weight may also be given. In addition to visual inspection of the astigmatism distribution diagram by a person, a computer program including AI may be used to analyze the astigmatism distribution and evaluate performance. The above example explains how to convert to Jackson's Cross Cylinder (JCC) notation before calculation, but you can also perform calculations without converting to JCC notation. In the above embodiment, visibility is used as a measure of weighting, but it is also possible to use visibility as a measure for calculation. The routine in Figure 3 is an example. In the routine in Figure 3, steps S1 to S3 are processed in (1), followed by steps S4 to S6 in (2). However, for example, the routine in (2) may be executed first, followed by the routine in (1), or the routines in (1) and (2) may be executed simultaneously in a multitasking manner. The present invention is not limited to the configurations described in the above embodiments. The components of each embodiment and variation may be arbitrarily selected and combined. Furthermore, any component of each embodiment or variation may be arbitrarily combined with any component described in the Summary of the Invention, or any component embodying any component described in the Summary of the Invention. The present invention also intends to obtain rights to these by filing an amendment or divisional application of this application. Furthermore, the applicant intends to obtain rights to the overall design or partial design by filing a conversion application to a design application. The drawings depict the entire device in solid lines, but they also include partial designs claimed for parts of the device. For example, a partial design may be a partial design for a part of the device, or a partial design may be included for a part of the device regardless of the part. A partial design may be a part of the device, or a part of that part.
Claims
1. A performance evaluation method for a progressive addition lens, comprising: determining astigmatism distribution data based on astigmatism data obtained by measuring mapping points distributed on a lens surface of the progressive addition lens; and evaluating the performance of the progressive addition lens based on the astigmatism distribution data, A method for evaluating the performance of a progressive power lens, comprising: setting a weight for ease of visibility or difficulty of visibility for each evaluation point according to the axial direction of the aberration component, which has an angle in the range of 0 to 180 degrees at the evaluation point; correcting the astigmatism data by reflecting the weight; and evaluating the performance of the progressive power lens based on the distribution state of the astigmatism data after the correction.
2. 2. The method for evaluating the performance of a progressive power lens according to claim 1, further comprising the steps of: creating an astigmatism distribution diagram based on the astigmatism data of the evaluation points; and evaluating the performance of the progressive power lens based on the astigmatism distribution diagram.
3. 3. The method for evaluating the performance of a progressive power lens according to claim 1, wherein the weight is set using the angle of the axis of the aberration component as a parameter, so that the weight is maximum or minimum when the axial direction of the aberration component is 45 degrees or 135 degrees, and conversely, is minimum or maximum when the axial direction is 0 degrees or 90 degrees.
4. 3. The method for evaluating the performance of a progressive power lens according to claim 1, wherein, when the prescribed power of the wearer includes astigmatism power, a correction process is performed in which the prescribed astigmatism power is subtracted from the astigmatism distribution data of the progressive power lens.
5. 3. The method for evaluating performance of a progressive power lens according to claim 1, wherein a function f(AX) having the axial angle of the aberration component as a parameter is maximum or minimum when the axial angle of the aberration component is 0 degrees, 90 degrees, or 180 degrees, and conversely is maximum or minimum when the axial angle of the aberration component is other than 0 degrees, 90 degrees, or 180 degrees, and wherein the astigmatism of the evaluation point after correction is determined by applying the function f(AX) as the weight to the astigmatism of the evaluation point before correction.
6. 3. The method for evaluating the performance of a progressive power lens according to claim 1, wherein a function f(AX) having the axial angle of the aberration component as a parameter is expressed by the following formula or an formula equivalent to the following formula, with a, b, ω, and α as coefficients: [Equation 1]
7. 7. The method for evaluating performance of a progressive-power lens according to claim 6, wherein the function f(AX) is expressed by the following formula or an formula equivalent to the following formula: [Equation 2]
8. 8. The method for evaluating performance of a progressive-addition lens according to claim 7, wherein the function f(AX) has a maximum or minimum value ranging from 1.1 to 2.0.