WO2025134815A1 - Eyeglass lens evaluation method, design method, selection method, and manufacturing method - Google Patents

Abstract

This eyeglass lens evaluation method comprises: a calculation step for calculating a three-dimensional clear vision region AC in a visual field space seen through an eyeglass lens (10) with the eyeglass lens (10) worn by a wearer; and an evaluation step for evaluating the performance of the eyeglass lens (10) on the basis of the obtained three-dimensional clear vision region. This three-dimensional clear vision region is calculated by obtaining, by means of MTF calculation, a range in which a contrast value is equal to or higher than a prescribed value.

Description

Methods for evaluating, designing, selecting and manufacturing eyeglass lenses

The present invention relates to a method for evaluating eyeglass lenses, a method for designing and selecting eyeglass lenses based on the evaluation, and a method for manufacturing eyeglass lenses based on these design and selection methods.

When manufacturing eyeglass lenses, it is necessary to design and manufacture eyeglass lenses that fit the wearer's eyes. For this reason, it is first necessary to evaluate and test the wearer's refraction and vision. Prior art documents related to such design, evaluation, and testing include Patent Document 1 and Patent Document 2.

JP 2001-318344 A JP 2014-85575 A

Spectacle lenses are designed and manufactured based on the results of testing the wearer's visual ability, but there is a problem in that it is difficult to evaluate whether spectacle lenses designed and manufactured in this way are suitable for the wearer.

In consideration of these problems, the present invention aims to provide a new method for evaluating eyeglass lenses, and to provide a design method and selection method for making eyeglass lenses suitable for the wearer based on this evaluation, as well as a method for manufacturing eyeglass lenses based on this design method and selection method.

The eyeglass lens evaluation method according to the present invention comprises a calculation step of calculating a three-dimensional clear vision area in the visual field seen through the eyeglass lenses of the eyeglasses when the wearer is wearing the eyeglasses, and an evaluation step of evaluating the performance of the eyeglass lens based on the calculated three-dimensional clear vision area.

The eyeglass lens design method according to the present invention includes a correction design step for correcting and designing the eyeglass lens based on the evaluation in the evaluation step.

The eyeglass lens design selection method according to the present invention includes a selection step for selecting an appropriate eyeglass lens design from a plurality of eyeglass lens designs prepared in advance based on the evaluation in the evaluation step.

The method for manufacturing eyeglass lenses according to the present invention includes a step of manufacturing eyeglass lenses based on the design in the above design step.

The method for manufacturing eyeglass lenses according to the present invention includes a step of manufacturing eyeglass lenses based on the selection made in the above selection step.

1 is a schematic diagram showing glasses having a pair of eyeglass lenses according to an embodiment of the present invention. 2A and 2B show examples of optical performance evaluation diagrams of a typical progressive power lens, in which FIG. 2A shows the astigmatism distribution of the lens, and FIG. 2B shows the power distribution (addition distribution) of the lens. 1 is a schematic cross-sectional view showing a state in which a wearer is wearing the spectacles, taken along a plane extending vertically through the center in the left-right direction of a right-eye spectacle lens. FIG. 4 is a graph in which the horizontal axis indicates the distance extending forward from the center O of the eye (center of the line of sight) in the line of sight G1 shown in FIG. 3, and the vertical axis indicates the contrast value C at each position on the line of sight G1. This is a schematic cross-sectional view showing the state in which a wearer is wearing the glasses, cut along a plane extending vertically through the center of the right eye's spectacle lens in the left-right direction, and showing the clear vision area visible through the right eye's spectacle lens in three-dimensional polar coordinates (D, φ, θ). This is a schematic cross-sectional view showing the state in which a wearer is wearing the glasses, cut along a plane extending vertically through the center of the right eye's spectacle lens in the left-right direction, and showing the clear vision area visible through the right eye's spectacle lens in three-dimensional polar coordinates (r, φ, θ). 7 is a plan sectional view showing a section taken along an arrow VII passing through the clear vision area AC(A) of the distance portion in FIG. 5 and showing the clear vision area in that section. 8 is a plan sectional view showing a cross section taken along an arrow VIII passing through a clear vision region AC(C) in the near portion of FIG. 5 and showing the clear vision region within that cross section. 11 is a graph showing the difference in change in contrast value C due to astigmatism in directions differing by 90 degrees. FIG. 2 is a schematic cross-sectional view showing the state in which the eyeglasses are worn by a wearer, cut along a plane extending vertically through the center of the right eye eyeglass lens in the left-right direction, and showing the clear vision area visible through the right eye eyeglass lens. This is a flowchart showing a series of steps for evaluating the three-dimensional clear vision area of a spectacle lens using the evaluation method of this embodiment, selecting and/or modifying the design of the spectacle lens based on this evaluation, and manufacturing the spectacle lens based on that design.

The following describes a preferred embodiment of the present invention. As an example of this embodiment, FIG. 1 shows a schematic diagram of eyeglasses 1 that are the subject of the eyeglass lens evaluation method of the present invention. As shown in FIG. 1, the eyeglasses 1 are composed of a right-eye eyeglass lens 10R used for the right eye EY (R), a left-eye eyeglass lens 10L used for the left eye EY (L), and an eyeglass frame 15 having left and right mounting openings 15R, 15L to which both eyeglass lenses 10R, 10L are attached. In this embodiment, the right-eye eyeglass lens 10R and the left-eye eyeglass lens 10L may be collectively referred to simply as eyeglass lens 10. The eyeglass lens 10 of this embodiment is a lens called a progressive power lens. The "up and down and left and right" positional relationship of the eyeglass lens 10 indicates the positional relationship when the eyeglass lens 10 is attached to the eyeglass frame 15 and used. In other words, when the wearer wears the eyeglasses 1, the up and down and left and right directions as seen by the wearer are referred to as the up and down and left and right directions of the eyeglasses 1 and the eyeglass lens 10. Furthermore, the direction in which the wearer looks through the eyeglass lenses 10 of the eyeglasses 1 will be referred to as the forward direction in this explanation.

As shown in FIG. 1, the right-eye spectacle lens 10R has a right-eye distance portion 11R located at the top, a right-eye near portion 12R formed below the right-eye distance portion 11R, and a right-eye progressive portion 13R formed in the middle by connecting the right-eye distance portion 11R and the right-eye near portion 12R. The right-eye distance portion 11R has a refractive power suitable for far vision, and the right-eye near portion 12R has a refractive power suitable for near vision. The refractive power of the right-eye progressive portion 13R changes continuously from a refractive power suitable for far vision to a refractive power suitable for near vision as it moves from the side closer to the right-eye distance portion 11R to the side closer to the right-eye near portion 12R.

As shown in FIG. 1, the left eye spectacle lens 10L has a left eye distance portion 11L located at the top, a left eye near portion 12L formed below the left eye distance portion 11L, and a left eye progressive portion 13L formed in the middle portion connecting the left eye distance portion 11L and the left eye near portion 12L. The left eye distance portion 11L has a refractive power suitable for far vision, and the left eye near portion 12L has a refractive power suitable for near vision. The refractive power of the left eye progressive portion 13L changes continuously from a refractive power suitable for far vision to a refractive power suitable for near vision as it moves from the side closer to the left eye distance portion 11L to the side closer to the left eye near portion 12L.

In this embodiment, "power" (unit: diopter [D]) is used as a numerical value to represent refractive power. In addition, the change in power in the progressive portion and near portion relative to the power in the distance portion (refractive power suitable for far vision) is called "addition power."

The eyeglass lens 10 is manufactured by manufacturing a lens 10A designed as shown in FIG. 2 and processing it to a shape that matches the shape of the mounting openings 15R, 15L of the eyeglass frame 15. As described above, the eyeglass lens 10 is a progressive power lens, and the lens 10A has an astigmatism distribution as shown in FIG. 2(A) and a power distribution (addition distribution) as shown in FIG. 2(B). Note that astigmatism is also generally referred to as astigmatic power, and astigmatism is sometimes referred to as astigmatic power in this specification.

The method for evaluating spectacle lenses according to the present invention will be explained below, taking a right-eye spectacle lens 10R as an example. The evaluation method of the present invention calculates a three-dimensional clear vision area in the forward visual space as seen through the spectacle lens 10, and evaluates lens performance, etc. based on the three-dimensional clear vision area. First, the calculation of this three-dimensional clear vision area will be explained. Figure 3 shows the state in which a wearer is wearing the glasses 1, cut along a plane that extends up and down through the left-right center of the right-eye spectacle lens 10R and also extends front-back. The spectacle lens 10 (right-eye spectacle lens 10R) is positioned in front of the wearer's right eye EY(R), and the wearer sees the forward visual space through the spectacle lens 10 with the right eye EY(R).

In FIG. 3, the right eye EY(R) has a crystalline lens on the front side, and the right eye EY(R) rotates around the eyeball rotation point O (center of the eyeball) to change the direction of its line of sight G, and the eye sees an object in front through various parts of the eyeglass lens 10. Standard values are about 13 mm for the distance from the eyeball rotation point O to the cornea, and about 12 mm for the distance from the cornea on the front side of the lens to the back side of the lens (the surface closer to the eye). The crystalline lens has a focusing ability, which allows people to see objects at distances from close to far with the naked eye, but eyeglasses 1 are needed when this focusing ability decreases. In the eyeglass lens evaluation method according to the present invention, even if the focusing ability decreases, each person has their own focusing ability, and it is necessary to take this into consideration when performing the evaluation. Normally, the distance from the eye is calculated based on the cornea, but in this application, a polar coordinate system centered on the eyeball rotation point O is used, so the starting point is the eyeball rotation point O.

The method for determining the three-dimensional clear vision area will be explained using as an example one line of sight G1 indicated by an arrow in Figure 3. The change in contrast value on this line of sight G1 is shown in Figure 4. In Figure 4, the horizontal axis represents the distance extending forward from the point of rotation O (center of the line of sight) on the line of sight G1 in diopter D units (1/m), and the vertical axis represents the contrast value C (distinguishable contrast value) seen at each position on the line of sight G1 by the right eye EY (R). For example, when the right eye EY (R) looks through the spectacle lens 10 on the line of sight G1, the spectacle lens 10 is designed so that it is in focus (comes into focus) at a position of distance d0, and the contrast value C is greatest at this position, and objects at this position appear most clearly.

As the position viewed by the right eye EY (R) through the eyeglass lens 10 moves forward and backward from the position of distance d0, the focus shifts (defocuses), causing blurring (out of focus), and the degree of this blurring increases as the distance increases from the position of distance d0. In accordance with the amount of blurring that occurs in this way, the contrast value C decreases as shown in FIG. 4. For example, the position of distance d0 is the most focused, so the contrast value C is close to 1.0, and the object viewed by the right eye EY (R) through the eyeglass lens 10 can be seen clearly without a decrease in contrast. Note that in this embodiment, the distance is specified in diopters D (unit: 1/m), but it may instead be expressed in actual length r (unit: m, etc.).

As the position of the object viewed by the right eye EY (R) through the eyeglass lens 10 moves forward and backward from the position at the distance d0, the blur increases, and the contrast value C, which indicates the degree to which the object can be identified at that position, decreases. The larger the contrast value C, the clearer the object can be seen, and the front-back area on the line of sight G1 where the contrast value C is greater than a predetermined threshold is determined to be the linear clear vision area. For example, as shown in FIG. 4, the contrast value C=0.2 can be set as the threshold, and the area AC (0.2) with a contrast value equal to or greater than this can be determined as the linear clear vision area. The linear clear vision area is not limited to this area AC (0.2), and for example, as shown in FIG. 4, the contrast value C=0.5 can be set as the threshold, and the area AC (0.5) with a contrast value equal to or greater than this can be determined as the linear clear vision area. In this way, the linear clear vision area AC can be set in various ways using the contrast value as the threshold, but first, an example will be described in which the contrast value C=0.2 is set as the threshold, and the area AC (0.2) with a contrast value equal to or greater than this can be determined as the linear clear vision area.

Note that Figure 4 shows an example in which the crystalline lens does not have a focusing function, but if it does have a focusing function, the width of the distance d0 at which the contrast value C becomes large will widen in the direction closer to the eye. Accordingly, the curve on the side closer to the eye than the distance d0 in Figure 4 will become a curve that has been translated in parallel to correspond to this wider width.

The linear clear vision area AC (0.2) on the line of sight G1 set in this manner is shown in Figure 3, where the line of sight G1 passes through one point on the eyeglass lens 10. By scanning this point on the eyeglass lens 10 and moving the line of sight G on the surface of the eyeglass lens 10 to integrate and display the linear clear vision area AC (0.2), a three-dimensional clear vision area AC as shown in Figures 5 to 8 can be obtained. As described above, the eyeglass lens 10 (10R) has a distance portion 11R, a progressive portion 13R, and a near portion 12R, each of which has a different focal position. For this reason, as shown in Figure 5, the three-dimensional clear vision area AC is composed of the distance portion clear vision area AC (A) when viewed through the distance portion 11R, the progressive portion clear vision area AC (B) when viewed through the progressive portion 13R, and the near portion clear vision area AC (C) when viewed through the near portion 12R. The distance portion 11R has a small power (negative) and a distance portion clear vision area AC(A) in the distance, the near portion 12R has a large power (addition power) and a near portion clear vision area AC(C) in the vicinity (positive), and the progressive portion 13R has a power (addition power) increasing from top to bottom, resulting in a progressive portion clear vision area AC(B) where the clear vision area gradually gets closer from the distance portion clear vision area AC(A) to the near portion clear vision area AC(C). As can be seen from this, the wearer of the spectacles 1 can see clearly in the distance through the distance portion 11R, can see clearly near through the near portion 12R, and can see clearly in the intermediate area through the progressive portion 13R.

When expressing the three-dimensional clear vision area AC as shown in Figures 5, 7, and 8, the up-down angle as shown in Figure 5 around the line of sight center O is taken as the up-down angle φ, the left-right angle as shown in Figures 7 and 8 around the line of sight center O is taken as the left-right angle θ, and it can be expressed in three-dimensional polar coordinates (D, φ, θ) using the distance D (diopters) from the line of sight center. In this case, Figure 5 shows a two-dimensional cross-sectional shape based on the up-down angle φ and the distance D. The distance D from the line of sight center is expressed in diopters.

Instead of the distance D in diopters, the distance r (m) may be used to display the distance in three-dimensional polar coordinates (r, φ, θ). Figure 6 shows an example of displaying the distance in three-dimensional polar coordinates (r, φ, θ) instead of Figure 5. The three-dimensional manifestation area is the same in Figures 5 and 6, but as shown, it differs greatly depending on whether it is diopters (D) or the actual distance r (m). Both the (D, φ, θ) coordinate system and the (r, φ, θ) coordinate system show the same content. The (D, φ, θ) system can be used during design evaluation, and the (r, φ, θ) system can be used when evaluating the usability of the lens in real space. In the following, the length in the line of sight direction will be explained using a diagram that shows the three-dimensional polar coordinates (D, φ, θ) using diopters (D).

The clear vision area AC(A) in the distance vision portion, the clear vision area AC(B) in the progressive vision portion, and the clear vision area AC(C) in the near vision portion shown in FIG. 5 are three-dimensional areas that also extend in the left-right direction of the eyeglass lens 10. To show this three-dimensional shape, FIG. 7 shows a planar cross section taken along arrow VII through the clear vision area AC(A) in FIG. 5, and FIG. 8 shows a planar cross section taken along arrow VIII through the clear vision area AC(C) in the near vision portion. FIGS. 7 and 8 show two-dimensional cross-sectional shapes based on the left-right angle θ and the distance D, and the three-dimensional shape of the clear vision area can be determined by combining this with the two-dimensional cross-sectional shape based on the up-down angle φ and the distance D in FIG. 5.

First, the clear vision area AC(A) for distance use shown in Figure 7 will be described. The clear vision area AC(A) for distance use is formed by the upper part of the eyeglass lens 10, and as shown in Figure 2(B), it has a lens configuration with a small diopter (negative) and a focus on the far side, and as shown in Figure 2(A), the astigmatism (astigmatic refractive power) is relatively small, occurring slightly on both the left and right sides of the clear vision area AC(A). If there was no astigmatism, the arc-shaped area surrounded by the dashed lines LA1 and LA2 in Figure 7 would be the clear vision area, but the clear vision area is slightly narrower as shown by the solid lines LA3 to LA6 due to the influence of astigmatism on both the left and right sides of the clear vision area AC(A).

Next, the near vision area AC(C) shown in FIG. 8 will be described. The near vision area AC(C) is formed by the lower part of the eyeglass lens 10, and as shown in FIG. 2(B), it is a lens configuration with a large (plus) power (addition power) and a focus on a nearby object. As shown in FIG. 2(A), astigmatism (cyanotic refractive power) is large on both the left and right sides of the near vision area AC(C). In the absence of astigmatism, the arc-shaped range surrounded by the dashed lines LC1 and LC2 in FIG. 8 is the clear vision area, but in the near vision area AC(C), the astigmatism increases rapidly as one moves to both the left and right sides. Due to the influence of this rapidly increasing astigmatism, the clear vision area rapidly narrows as one moves to both the left and right sides, as shown by the solid lines LC3 to LC6. For this reason, it is often the case that the clear vision area disappears as one moves toward both the left and right ends of the near vision area AC(C).

The decrease in contrast value C due to astigmatism differs depending on the direction within a plane (the surface of the eyeglass lens 10) perpendicular to the optical axis. For example, the change in contrast value C differs between the left-right direction and the up-down direction of the eyeglass lens 10 (i.e., directions that differ by 90 degrees). In this regard, the contrast value C on the line of sight G2 indicated by the arrow in FIG. 8 will be explained with reference to FIG. 9. FIG. 9 is a graph showing the position of line of sight G2 on the horizontal axis and the contrast value C on the vertical axis, which is the result of a so-called MTF (Modulation Transfer Function) calculation. The position FP2 at which the image is in focus on the line of sight G2 is shown on the horizontal axis as the origin position 0 in FIG. 9. In FIG. 9, positions forward of this origin position 0 (FP2) are shown as positive values on the horizontal axis, and positions closer to the viewer are shown as negative values.

Because the astigmatism of the eyeglass lens 10 is large on the line of sight G2, for example, the contrast value C of the focal line in the left-right direction is largest at the origin position 0, as shown by the dashed line C(1), and decreases as it moves forward and backward from the origin position 0. On the other hand, the contrast value C of the focal line in the up-down direction is largest at a position of about 0.25D, as shown by the dashed line C(2), and decreases as it moves forward and backward from the position of about 0.25D. In this way, it is necessary to determine the clear vision area based on the contrast value C that differs in the left-right direction and the up-down direction of the eyeglass lens 10 (i.e., the vertical direction and the horizontal direction that differ by 90 degrees). For this reason, at each position on the line of sight G2, the geometric mean contrast value C(B) of the contrast value C(1A) on the dashed line C(1) and the contrast value C(2A) on the dashed line C(2) is calculated, and the clear vision area is determined by the geometric mean contrast value C(B). The geometric mean contrast value C(B) is the square root of the product of the contrast value C(1A) and the contrast value C(2A). The geometric mean contrast value C(B) calculated in this way is the value indicated by the solid line C(0) on the line of sight G2, and the range where the contrast value C is 0.2 or more on this solid line C(0) is the clear vision region. The calculation of the geometric mean contrast value C(B) based on the above formula is one example, and other calculation methods may be used, such as based on the position of approximately -0.2D on the negative end of the contrast value C(1A) and the position of approximately 0.5D on the positive end of the contrast value C(2A).

The contrast value C that determines the clear vision range can be set to various standards as threshold values, such as a standard contrast value that does not impair the readability of the object, a high contrast value where no reduction in contrast is felt, or a low contrast value where text is just barely legible. This makes it possible to carry out a variety of evaluations, as described below.

The setting of the clear vision area using contrast value C as explained above is based on the contrast value at each position of the lens, and the three-dimensional clear vision area is set using the so-called MTF (Modulation Transfer Function). In this case, in the cross-sectional view shown in Figure 5, the power changes depending on the vertical angle (angle φ), so the clear vision area moves closer from AC(A) to AC(C). The clear vision areas shown in Figures 7 and 8 (distance clear vision area AC(A) and near clear vision area AC(C)) correspond to the height (angle φ) at the left-right angle (angle θ), and the three-dimensional clear vision area is determined by the MTF.

The above describes an example in which the range where the contrast value C is 0.2 or more is set as the clear vision area AC (0.2). However, as described above, the clear vision area can also be set based on a different contrast value C. For example, as shown in FIG. 4, the contrast value C=0.5 may be set as a threshold, and the area AC (0.5) where the contrast value is equal to or greater than this may be set as the clear vision area. As shown in FIG. 10, the range of the clear vision area set in this way is the range sandwiched between two equal contrast planes LA1 (0.2) and LA2 (0.2) before and after which the contrast value C=0.2 becomes the clear vision area AC (0.2), and the range sandwiched between two equal contrast planes LA1 (0.5) and LA2 (0.5) before and after which the contrast value C=0.5 becomes the clear vision area AC (0.5). Naturally, the clear vision area AC (0.2) is a wider area than the clear vision area AC (0.5). Also, the equal contrast plane LA (FP) where the focus is best and the contrast value C is the largest is located in the middle position.

The three-dimensional clear vision area is set in the above manner, and the lens performance is evaluated based on the three-dimensional clear vision area thus set. The three-dimensional clear vision area can be calculated by integrating the coordinate values (D, φ, θ) in the clear vision area AC(0.2) over the entire area. For example, for the clear vision area AC(0.2) in the line of sight G1 shown in FIG. 3, the line of sight G1 is moved within the visible range passing through the spectacle lens 10 at an angle φ in the vertical direction, and also moved within the visible range passing through the spectacle lens 10 at an angle θ in the horizontal direction, and moved in the front-back direction (D) within the visible range, and the clear vision area AC(0.2) at this time is integrated and calculated. The performance of the spectacle lens 10 can be evaluated based on the three-dimensional clear vision area thus determined. This evaluation is preferably performed in combination with the position in the line of sight G direction. For example, it is preferable to evaluate the determined three-dimensional clear vision area in relation to the position in the line of sight of the isocontrast planes LA1(0.2) and LA2(0.2) that define the clear vision area AC(0.2) and the isocontrast plane LA(FP) that is most in focus and has the largest contrast value C, and to evaluate the performance of the eyeglass lens.

In evaluating this three-dimensional clear vision region, the performance of the eyeglass lens 10 can be evaluated based on the entire visible range of the eyeglass lens 10. In this case, the entire region can be evaluated by combining it with the positional relationship in the direction of the line of sight G or with the position relative to the contrast surface. Each of the regions of the distance portion 11R, the progressive portion 13R, and the near portion 12R in the eyeglass lens 10 can also be evaluated by combining it with the positional relationship in the direction of the line of sight G or with the position relative to the contrast surface. In this way, the lens performance can be evaluated separately for each of the distance portion 11R, the progressive portion 13R, and the near portion 12R. It is also possible to obtain a region limited to a desired range in the eyeglass lens 10 and evaluate the lens performance within the limited range based on this. For example, it is possible to obtain a region limited to a range where the central astigmatism of the near portion 12R is small, and to evaluate the lens performance during reading, for example, based on this.

Lens evaluation is based on the ease (whether the wearer can see what they want to see) when using the lenses, for example, to drive a car, watch television, operate a computer or mobile device, read, or perform detailed manual tasks. Specifically, if the wearer can see everything they want to see, it is highly rated, and important indicators include how large the clear vision area is and how much of what they want to see is covered. Also, with progressive power lenses, there are visual targets for long, medium, and close distances, so the evaluation is a combination of these. For example, it is possible to set an emphasis for each purpose and evaluate them, such as driving a car: 5, computer: 3, reading: 2, etc. Information about these intended uses is obtained through interviews and questionnaires at opticians. This information is then sent to the manufacturer for design evaluation.

The above-described evaluation method allows the performance of the eyeglass lens to be evaluated, and based on this evaluation, the eyeglass lens design can be modified or an appropriate eyeglass lens design can be selected from multiple eyeglass lens designs prepared in advance. Furthermore, by manufacturing eyeglass lenses based on the modification of the design performed in this manner or the selection of an appropriate eyeglass lens design, an eyeglass lens suitable for the wearer and his/her intended use can be obtained. This series of steps will be described with reference to FIG. 11.

As shown in FIG. 11, this series of steps includes an information acquisition step S10 in which a vision test such as a refraction test is performed on the eyeglass wearer and various information is acquired to acquire information on eyeglass lenses suitable for the wearer; a base design step 20 in which a base eyeglass lens is designed or lens design data is acquired based on the information thus acquired; an evaluation step S30 in which an eyeglass lens is evaluated based on the base eyeglass lens design (evaluation of whether the eyeglass lens is suitable for the wearer's purpose); an eyeglass lens redesign step S40 in which an eyeglass lens design is selected or modified if this evaluation is unsuccessful; and an eyeglass lens manufacturing step S50 in which eyeglass lenses are manufactured based on this design if the evaluation in the evaluation step S30 is successful.

The base eyeglass lens design step S10 is a work step that is currently generally carried out at eyeglass stores. First, in the refraction (vision) test step S11, the person (wearer) undergoes a refraction test and vision test similar to those carried out at ordinary eyeglass stores. Then, in the interview step S12, the wearer is asked what he or she will be using the eyeglasses for, how often they will be used, and how important that is, in order to design lenses that suit the person's eyes. Then, distance information to a visual object (e.g. a computer screen) that corresponds to the intended use is obtained (distance information acquisition step S13). The data for lens design obtained in this way is sent to the eyeglass lens manufacturer, who uses the data received to design the base eyeglass lens and obtains lens design data (base design step S20).

In addition, in the base design step S20, instead of designing a base eyeglass lens, it is also possible to prepare various types of base eyeglass lens designs in advance and select a base eyeglass lens design that suits the wearer's purpose and use based on the results of the refraction test and visual (eyesight) test obtained in step S10, the purpose for which the eyeglasses will be used, and information on the distance to the visual target.

Next, in evaluation step S30, an evaluation is performed to determine whether the base spectacle lens design designed or selected in this manner is suitable for the wearer. This evaluation step S30 includes a three-dimensional clear vision area calculation step S31 for calculating a three-dimensional clear vision area based on the base spectacle lens design by calculating the three-dimensional clear vision area, an evaluation step S32 for evaluating whether the three-dimensional clear vision area calculated in this manner matches the intended use, etc., and a judgment step S33 for deciding the next step to proceed to based on the evaluation in evaluation step S32.

In step S31, which calculates the three-dimensional clear vision area, as described above with reference to Figures 3 and 4, the wearer wears the eyeglass lens 10, and calculates the area AC (0.2) where the contrast value C is 0.2 or more on the line of sight G when looking through the eyeglass lens. Then, the line of sight G is moved within the visible range of the eyeglass lens to integrate the area AC (0.2), and the three-dimensional clear vision area is calculated as shown in Figures 5 to 8. Next, in step S32, the performance of the base eyeglass lens is evaluated based on the calculated three-dimensional clear vision area. As described above, this evaluation is performed in relation to the position on the line of sight G or the position of an equal contrast surface, or based on an area limited to a desired range of the eyeglass lens 10. The desired range here is, for example, driving a car, watching TV, operating a computer, operating a mobile device, reading, detailed manual work, or a combination of these. It is also possible to set the degree of importance according to the purpose using a questionnaire, for example, car: 5, computer: 3, reading: 2, etc.

If the evaluation in step S32 is successful, the process proceeds from decision step S33 to spectacle lens manufacturing step S50, where spectacle lenses are manufactured based on the spectacle lens design performed in base design step S20 or the acquired lens design data. On the other hand, if the evaluation in step S32 is unsuccessful, the process proceeds from decision step S33 to spectacle lens redesign step S40, where a spectacle lens design is selected or revised. Once the design has been reselected or revised in this manner, the process returns to three-dimensional clear vision area calculation step S31, and the three-dimensional clear vision area is calculated based on this reselection or revision. The above steps are then repeated from step S32 onwards.

By following the above steps, eyeglass lenses are manufactured based on eyeglass lens design data that has passed the evaluation in step S32, making it possible to create eyeglass lenses that are optimally suited to the wearer's visual acuity and intended use.

1 Pair of eyeglass lenses 10 Eyeglass lens 10R Eyeglass lens for right eye 10L Eyeglass lens for left eye 11R, 11L Near vision portion for right eye and left eye 12R, 12L Distance vision portion for right eye and left eye 13R, 13L Progressive vision portion for right eye and left eye C Contrast value G Line of sight

Claims (18)

A calculation step of calculating a three-dimensional clear vision area in a visual field seen through a spectacle lens of the glasses when a wearer wears the glasses;
and an evaluation step of evaluating performance of the eyeglass lens based on the determined three-dimensional clear vision area. In the calculation step,
Calculating a linear clear vision area on a straight line extending from the wearer's eye through a predetermined position within the visible range of the spectacle lens;
The method for evaluating a spectacle lens according to claim 1 , wherein the predetermined position is moved within a visible range of the spectacle lens and the linear clear vision area is integrated to calculate the three-dimensional clear vision area. In the calculation step,
The visual field space seen through the spectacle lens is defined by an up-down angle (φ) and a left-right angle (θ) covering the visible range of the spectacle lens as seen from the wearer's eye, and a distance index (D) indicating a position on a straight line extending from the wearer's eye through a predetermined position within the visible range of the spectacle lens, and the three-dimensional clear vision area is expressed by three-dimensional polar coordinates (D, φ, θ);
The method for evaluating a spectacle lens according to claim 1 , wherein the three-dimensional clear vision area is calculated by integrating the positions within the clear vision area expressed by the three-dimensional polar coordinates (D, φ, θ) within the clear vision area. In the calculation step,
The visual field space seen through the spectacle lens is defined by the vertical angle (φ) and horizontal angle (θ) covering the visible range of the spectacle lens as seen from the wearer's eye, and the distance (r) from the wearer's eye to a position on a straight line extending through a predetermined position within the visible range of the spectacle lens, and the three-dimensional clear vision area is expressed by three-dimensional polar coordinates (r, φ, θ);
The method for evaluating a spectacle lens according to claim 1 , wherein the three-dimensional clear vision area is calculated by integrating the positions within the clear vision area expressed by the three-dimensional polar coordinates (r, φ, θ) within the clear vision area. The method for evaluating eyeglass lenses according to claim 1, wherein the three-dimensional clear vision area corresponds to a range in which the contrast value of an object viewed by a wearer through the eyeglass lens while wearing the eyeglasses is equal to or greater than a predetermined value. The method for evaluating eyeglass lenses according to claim 5, in which the range in which the contrast value is equal to or greater than a predetermined value is determined by MTF calculation. The method for evaluating eyeglass lenses according to claim 5, wherein a plurality of contrast values, such as a contrast value that does not impair the readability of an object and a contrast value to the extent that a decrease in contrast is not felt, are used as the contrast value that defines the three-dimensional clear vision area, and the three-dimensional clear vision area is selected and set based on the judgment levels of such a plurality of contrast values. The method for evaluating eyeglass lenses according to claim 1, further comprising determining an equal-contrast surface in which the contrast values are equal within the visible range of the eyeglass lens, and using the equal-contrast surface to define the three-dimensional clear vision area. The method for evaluating eyeglass lenses according to claim 1, wherein in the evaluation step, the performance of the eyeglass lens is evaluated by evaluating the three-dimensional clear vision area in combination with the distance on a straight line extending from the wearer's eye through the eyeglass lens. The method for evaluating eyeglass lenses according to claim 8, wherein in the evaluation step, the performance of the eyeglass lens is evaluated by evaluating the three-dimensional clear vision area in combination with the position of the equal contrast surface. The method for evaluating eyeglass lenses according to claim 1, wherein in the evaluation step, a predetermined range is selected and set from the visible range of the eyeglass lens, a three-dimensional clear vision area within the set range is obtained, and the performance of the eyeglass lens is evaluated based on the three-dimensional clear vision area thus obtained within the predetermined area. the spectacle lens is a progressive power lens,
The method for evaluating a spectacle lens according to claim 11, wherein at least one of a distance portion, a progressive portion, and a near portion of the bifocal spectacle lens is set to the predetermined range. The method for evaluating eyeglass lenses according to claim 11, in which the predetermined range is selected and set based on an MTF calculation of the progressive power lens. The method for evaluating eyeglass lenses according to claim 1, wherein in the evaluation step, the performance of the eyeglass lens is evaluated based on the degree to which the three-dimensional clear vision area covers visual objects present in a visual field visible through the eyeglass lenses of the eyeglasses when the wearer is wearing the eyeglasses. A method for designing eyeglass lenses, comprising a design step of correcting and designing the eyeglass lenses based on the evaluation in the evaluation step according to any one of claims 1 to 14. A method for selecting eyeglass lenses, comprising a selection step of selecting an appropriate eyeglass lens design from a plurality of eyeglass lens designs prepared in advance based on the evaluation by the evaluation step according to any one of claims 1 to 14. A method for manufacturing eyeglass lenses, comprising a step of manufacturing eyeglass lenses based on a design according to the design step described in claim 15. A method for manufacturing a spectacle lens, comprising the step of manufacturing a spectacle lens based on the selection made by the selecting step according to claim 16.

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