Eyeglass lens evaluation method, design method, selection method, and manufacturing method

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

[0001] The present invention relates to a method for evaluating spectacle lenses, a method for designing and selecting spectacle lenses based on the evaluation, and a method for manufacturing spectacle lenses based on these design and selection methods.

[0002] 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 Documents 1 and 2.

[0003] JP 2001-318344 A JP 2014-85575 A

[0004] 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 the spectacle lenses designed and manufactured in this way are suitable for the wearer.

[0005] In view of the above problems, the present invention aims to provide a new method for evaluating spectacle lenses, a design method and a selection method for making spectacle lenses suitable for a wearer based on this evaluation, and a method for manufacturing spectacle lenses based on these design and selection methods.

[0006] The method for evaluating eyeglass lenses according to the present invention comprises a calculation step of calculating a three-dimensional clear vision area within a visual field visible 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 lenses based on the calculated three-dimensional clear vision area.

[0007] The method for designing a spectacle lens according to the present invention comprises a corrective design step of correcting and designing the spectacle lens based on the evaluation in the evaluation step.

[0008] The eyeglass lens design selection method according to the present invention comprises a selection step of selecting an appropriate eyeglass lens design from a plurality of eyeglass lens designs prepared in advance, based on the evaluation in the evaluation step.

[0009] A method for manufacturing a spectacle lens according to the present invention comprises a step of manufacturing a spectacle lens based on the design in the above design step.

[0010] A method for manufacturing a spectacle lens according to the present invention comprises a step of manufacturing a spectacle lens based on the selection made in the above-mentioned selection step.

[0011] 2 is a schematic diagram showing eyeglasses having a pair of eyeglass lenses according to the present embodiment. It shows an example of an optical performance evaluation diagram of a general progressive power lens, with FIG. 2(A) showing the astigmatism distribution of the lens and FIG. 2(B) showing the power distribution (addition distribution) of the lens. It is a schematic cross-sectional view showing a state in which a wearer is wearing eyeglasses, cut along a plane extending vertically at the center in the left-right direction of the eyeglass lens for the right eye. It is a graph showing on the horizontal axis 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 on the vertical axis the contrast value C at each position on the line of sight G1. It is a schematic cross-sectional view showing a state in which a wearer is wearing eyeglasses, cut along a plane extending vertically at the center in the left-right direction of the eyeglass lens for the right eye, and showing the clear vision area seen through the eyeglass lens for the right eye in three-dimensional polar coordinates (D, φ, θ). 5 is a schematic cross-sectional view showing a state in which a wearer is wearing eyeglasses, the right-eye spectacle lens being cut along a plane extending vertically at the center in the left-right direction, and the clear vision area seen through the right-eye spectacle lens being represented by three-dimensional polar coordinates (r, φ, θ). FIG. 6 is a planar cross-sectional view showing a cross-section taken along arrow VII passing through the distance clear vision area AC(A) of FIG. 5 and the clear vision area within that cross-section. FIG. 6 is a planar cross-sectional view showing a cross-section taken along arrow VIII passing through the near clear vision area AC(C) of FIG. 5 and the clear vision area within that cross-section. FIG. 7 is a graph showing the difference in change in contrast value C in directions differing by 90 degrees due to astigmatism. FIG. 7 is a schematic cross-sectional view showing a state in which a wearer is wearing eyeglasses, the right-eye spectacle lens being cut along a plane extending vertically at the center in the left-right direction, and the clear vision area seen through the right-eye spectacle lens. FIG. 8 is a flowchart showing a series of steps in which the three-dimensional clear vision area of ​​a spectacle lens is evaluated by the evaluation method according to the present embodiment, the design of the spectacle lens is selected and / or modified based on the evaluation, and the spectacle lens is manufactured based on the selected design.

[0012] A preferred embodiment of the present invention will now be described. As an example of this embodiment, FIG. 1 schematically shows eyeglasses 1, which 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 for use in the right eye EY(R), a left-eye eyeglass lens 10L for use in the left eye EY(L), and an eyeglass frame 15 having left and right mounting openings 15R and 15L into which both eyeglass lenses 10R and 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 so-called progressive-power lens. The "up-down and left-right" positional relationships of the eyeglass lens 10 refer to the positional relationships when the eyeglass lens 10 is attached to the eyeglass frame 15 and used. In other words, the up-down and left-right directions as seen from the wearer when wearing the eyeglasses 1 are referred to as the up-down and left-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 the following description.

[0013] 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 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 distance 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 distance 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.

[0014] 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 an intermediate 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 distance 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 distance vision to a refractive power suitable for near vision as it moves from a side closer to the left-eye distance portion 11L to a side closer to the left-eye near portion 12L.

[0015] In this embodiment, "power" (unit: diopter [D]) is used as a numerical value representing refractive power. Furthermore, the change in power in the progressive portion and near portion relative to the power in the distance portion (refractive power suitable for distance vision) is referred to as "addition power."

[0016] The eyeglass lens 10 is manufactured by manufacturing a lens 10A designed as shown in Fig. 2 and then processing it to a shape that matches the shapes 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 will also be referred to as astigmatic power in this specification.

[0017] A method for evaluating spectacle lenses according to the present invention will be described 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 described. Figure 3 shows a state in which a wearer is wearing the glasses 1, with the right-eye spectacle lens 10R cut along a plane extending vertically and longitudinally through the center in the left-right direction. The spectacle lens 10 (right-eye spectacle lens 10R) is positioned in front of the wearer's right eye EY(R), and the wearer views the forward visual space through the spectacle lens 10 with the right eye EY(R).

[0018] In FIG. 3 , the right eye EY(R) has a crystalline lens at the front, and as the right eye EY(R) rotates around the center of rotation O (the center of the eyeball), the direction of its line of sight G changes, and the eye sees an object in front of it through various points on the spectacle lens 10. Typical values ​​are approximately 13 mm for the distance from the center of rotation O to the cornea, and approximately 12 mm for the distance from the cornea on the front surface of the lens to the rear surface of the lens (the surface closest to the eye). The crystalline lens has the ability to adjust focus, which allows people to see objects at distances from near to far with the naked eye. When this ability to adjust focus decreases, eyeglasses 1 become necessary. In the spectacle lens evaluation method according to the present invention, even if the ability to adjust focus decreases, each person still has the ability to adjust focus, and this must be taken into account when making the evaluation. While the distance from the eye is usually measured starting from the cornea, this application uses a polar coordinate system centered on the center of rotation O, and therefore the starting point is the center of rotation O.

[0019] A method for determining the three-dimensional clear vision area will be described using one line of sight G1 indicated by an arrow in Figure 3 as an example. Changes in contrast value along this line of sight G1 are shown in Figure 4. In Figure 4, the horizontal axis represents the distance extending forward from the center of rotation O (center of the line of sight) along the line of sight G1 in diopter D units (1 / m), and the vertical axis represents the contrast value C (discriminative contrast value) seen by the right eye EY(R) at each position along the line of sight G1. For example, when the right eye EY(R) looks through the spectacle lens 10 along the line of sight G1, the spectacle lens 10 is designed so that the focus is at a position of distance d0, at which the contrast value C is greatest and objects at this position appear most clearly.

[0020] As the position viewed by the right eye EY(R) through the eyeglass lens 10 moves forward and backward from the distance d0, the focus shifts (defocuses), resulting in blurring (out-of-focus), and the degree of this blurring increases with increasing distance from the distance d0. As shown in FIG. 4, the contrast value C decreases in accordance with the magnitude of the blurring. For example, at the distance d0, the focus is at its best, 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 clearly seen without a decrease in contrast. In this embodiment, the distance is specified in diopters D (unit: 1 / m), but it may alternatively be expressed in terms of the actual length r (unit: m, etc.).

[0021] As the position of the object viewed by the right eye EY (R) through the spectacle lens 10 moves forward and backward from the distance d0, blurring increases, and the contrast value C, which indicates the degree to which the object can be identified at that position, decreases. The higher the contrast value C, the clearer the object can be seen. A region in the front-to-back direction along the line of sight G1 where the contrast value C is greater than a predetermined threshold is determined as the linear clear vision region. For example, as shown in FIG. 4 , a contrast value C of 0.2 can be set as the threshold, and a region AC (0.2) with a contrast value equal to or greater than this threshold can be determined as the linear clear vision region. The linear clear vision region is not limited to this region AC (0.2). For example, as shown in FIG. 4 , a contrast value C of 0.5 can be set as the threshold, and a region AC (0.5) with a contrast value equal to or greater than this threshold can be determined as the linear clear vision region. While the linear clear vision region AC can be set in various ways using a contrast value as the threshold, a description will first be given of an example where a contrast value C of 0.2 is set as the threshold, and a region AC (0.2) with a contrast value equal to or greater than this threshold is determined as the linear clear vision region.

[0022] 4 shows an example in which the crystalline lens does not have a focusing function, but if it does have a focusing function, the range of the distance d0 at which the contrast value C increases will widen in the direction closer to the eye. Accordingly, the curve on the side closer to the eye than the distance d0 in FIG. 4 will become a curve that has shifted in parallel in accordance with this widening range.

[0023] The linear clear vision area AC(0.2) on the line of sight G1 set in this manner is shown in Figure 3. The line of sight G1 passes through a single point on the spectacle lens 10. By scanning this point on the spectacle lens 10 and moving the line of sight G on the surface of the spectacle lens 10 to integrate and display the linear clear vision area AC(0.2), a three-dimensional clear vision area AC can be obtained as shown in Figures 5 to 8. As described above, the spectacle lens 10 (10R) has a distance portion 11R, a progressive portion 13R, and a near portion 12R, each of which is focused at a different position. Therefore, as shown in Figure 5, the three-dimensional clear vision area AC is composed of a distance portion clear vision area AC(A) when viewed through the distance portion 11R, a progressive portion clear vision area AC(B) when viewed through the progressive portion 13R, and a near portion clear vision area AC(C) when viewed through the near portion 12R. The distance portion 11R has a small power (negative) and has a distance clear vision region AC(A) in the distance, the near portion 12R has a large power (addition power) and has a near clear vision region AC(C) in the vicinity, and the power (addition power) of the progressive portion 13R increases from top to bottom, resulting in a progressive clear vision region AC(B) where the clear vision region gradually approaches from the distance clear vision region AC(A) to the near clear vision region AC(C). As can be seen from this, the wearer of the spectacles 1 can see far away clearly through the distance portion 11R, can see close up clearly through the near portion 12R, and can see clearly in the intermediate region through the progressive portion 13R.

[0024] When expressing the three-dimensional clear vision region AC as shown in Figures 5, 7, and 8, the angle in the up-down direction as shown in Figure 5 about the line of sight center O is defined as the up-down angle φ, the angle in the left-right direction as shown in Figures 7 and 8 about the line of sight center O is defined as the left-right angle θ, and the distance D (diopter) from the line of sight center can be used to express the region AC in three-dimensional polar coordinates (D, φ, θ). 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.

[0025] Instead of the distance D in diopters, the distance r (m) may be displayed 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 display area is the same in Figures 5 and 6, but as shown, it differs significantly 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. For example, the (D, φ, θ) system is used for design evaluation, and the (r, φ, θ) system is used when evaluating the usability of a lens in real space. In the following, the length in the line of sight direction will be described using a diagram representing the three-dimensional polar coordinates (D, φ, θ) using diopters (D).

[0026] The distance vision region AC(A), progressive vision region AC(B), and near vision region AC(C) shown in Fig. 5 are three-dimensional regions that also extend in the left-right direction of the spectacle lens 10. To illustrate this three-dimensional shape, Fig. 7 shows a planar cross section taken along arrow VII through the distance vision region AC(A) shown in Fig. 5, and Fig. 8 shows a planar cross section taken along arrow VIII through the near vision region AC(C). 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 region 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.

[0027] First, we will explain the distance vision area AC(A) shown in Fig. 7. The distance vision area AC(A) is formed by the upper part of the spectacle lens 10, and as shown in Fig. 2(B), it has a lens configuration with a small diopter (negative) and a focus on a distant object. As shown in Fig. 2(A), astigmatism (astigmatic refractive power) is relatively small, occurring only slightly on both the left and right sides of the distance vision area AC(A). If there were no astigmatism, the arc-shaped area surrounded by the dashed dotted lines LA1 and LA2 in Fig. 7 would be the clear vision area, but due to the influence of astigmatism on both the left and right sides of the distance vision area AC(A), the clear vision area becomes slightly narrower as shown by the solid lines LA3 to LA6.

[0028] 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 portion of the spectacle lens 10, and as shown in FIG. 2(B), it has a lens configuration with a large (positive) power (addition power) and a near focus. As shown in FIG. 2(A), astigmatism (astigmatic refractive power) increases on both the left and right sides of the near vision area AC(C). In the absence of astigmatism, the arc-shaped area enclosed by the dashed-dotted lines LC1 and LC2 in FIG. 8 would be the clear vision area. However, in the near vision area AC(C), astigmatism increases rapidly toward both the left and right sides. Due to the influence of this rapidly increasing astigmatism, the clear vision area rapidly narrows toward 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 toward the left and right ends of the near vision area AC(C).

[0029] The decrease in contrast value C due to astigmatism varies 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). Regarding this, 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 the line of sight G2 on the horizontal axis and the contrast value C on the vertical axis, and 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 indicated by positive values ​​on the horizontal axis, and positions closer to the viewer are indicated by negative values.

[0030] Because the astigmatism of the spectacle lens 10 is large along 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 the focal line moves forward or 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 approximately 0.25D, as shown by the dashed line C(2), and decreases as the focal line moves forward or backward from the position of approximately 0.25D. In this way, it is necessary to determine the clear vision region based on the contrast values ​​C that differ in the left-right and up-down directions of the spectacle lens 10 (i.e., the vertical and horizontal directions that are 90 degrees apart). For this reason, at each position along 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 region is determined based on 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 on this solid line C(0) where the contrast value C is 0.2 or more is the clear vision region. The calculation of the geometric mean contrast value C(B) based on the above equation is just one example, and other calculation methods may be used, such as based on a position of approximately -0.2D on the negative side of the contrast value C(1A) to a position of approximately 0.5D on the positive side of the contrast value C(2A).

[0031] 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 cause any problems in the readability of the object, a high contrast value that does not cause any noticeable decrease in contrast, or a low contrast value that allows characters to be just barely readable. This makes it possible to perform a variety of evaluations, as will be described later.

[0032] The above-described setting of the clear vision area using the contrast value C 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 FIG. 5, the power changes depending on the vertical angle (angle φ), so the clear vision area moves from AC(A) to AC(C) toward the near side. The clear vision areas (distance vision area AC(A) and near vision area AC(C)) shown in FIGS. 7 and 8 correspond to the height (angle φ) at the horizontal angle (angle θ), and the three-dimensional clear vision area is determined by the MTF.

[0033] The above describes an example in which the range where the contrast value C is 0.2 or greater is set as the clear vision region AC(0.2). However, as mentioned above, the clear vision region can also be set based on a different contrast value C. For example, as shown in FIG. 4, a contrast value C of 0.5 may be set as a threshold, and the region AC(0.5) where the contrast value is equal to or greater than this may be set as the clear vision region. The clear vision region AC(0.2) is set as the range between two equal-contrast planes LA1(0.2) and LA2(0.2) on either side of which the contrast value C is 0.2, and the clear vision region AC(0.5) is set as the range between two equal-contrast planes LA1(0.5) and LA2(0.5) on either side of which the contrast value C is 0.5. Naturally, the clear vision region AC(0.2) is wider than the clear vision region AC(0.5). Furthermore, the equal-contrast plane LA(FP), which is the most focused and has the largest contrast value C, is located in the middle position.

[0034] The three-dimensional clear vision area is set as described above, and lens performance is evaluated based on the set three-dimensional clear vision area. The three-dimensional clear vision area can be calculated by integrating the coordinate values ​​(D, φ, θ) within the clear vision area AC(0.2) over the entire area. For example, for the clear vision area AC(0.2) at the line of sight G1 shown in FIG. 3, the line of sight G1 can be 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-to-back direction (D) within the visible range, and the clear vision area AC(0.2) at each time can be integrated to obtain the clear vision area. 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. 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 best in focus and has the largest contrast value C, and to evaluate the performance of the eyeglass lens.

[0035] 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 visible range can be evaluated by combining this entire range with its position in the direction of the line of sight G or its position relative to the contrast surface. Each of the distance vision zone 11R, progressive zone 13R, and near vision zone 12R of the eyeglass lens 10 can also be evaluated by combining its position in the direction of the line of sight G or its position relative to the contrast surface. This allows the lens performance of each of the distance vision zone 11R, progressive zone 13R, and near vision zone 12R to be evaluated separately. Furthermore, the eyeglass lens 10 can be determined within a desired range, and lens performance within the range can be evaluated based on this range. For example, the area can be determined by limiting the area to a range with small central astigmatism in the near vision zone 12R, and lens performance during reading, for example, can be evaluated based on this area.

[0036] Lens evaluations are based on the ease with which the wearer can see what they want to see when using the lenses, for example, when driving a car, watching television, using a computer or mobile device, reading, or performing detailed manual tasks. Specifically, a high rating is given if the wearer can see everything they want to see, and important indicators include the size (area) of the clear vision area and how much of what they can cover. Furthermore, progressive power lenses have visual targets for far, intermediate, and near distances, so the evaluation is based on a combination of these. For example, it is possible to set a priority level for each purpose, such as driving a car: 5, using a computer: 3, and reading: 2. Information about these intended uses is obtained through interviews and questionnaires at opticians. This information is then sent to the manufacturer for design evaluation.

[0037] The performance of the spectacle lens can be evaluated using the evaluation method described above, and the spectacle lens design can be modified based on this evaluation, or an appropriate spectacle lens design can be selected from a plurality of spectacle lens designs prepared in advance. Furthermore, if spectacle lenses are manufactured based on the modification of the design or the selection of an appropriate spectacle lens design, spectacle lenses suitable for the wearer and their intended use can be obtained. This series of steps will be described with reference to FIG.

[0038] 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 spectacle wearer and various information is acquired to acquire information on spectacle lenses suitable for the wearer; a base design step 20 in which a base spectacle lens is designed or lens design data is acquired based on the information thus acquired; an evaluation step S30 in which an evaluation of the spectacle lens is performed based on the base spectacle lens design (an evaluation of whether the spectacle lens is suitable for the wearer's intended use); a spectacle lens redesign step S40 in which a spectacle lens design is selected or modified if the evaluation in the evaluation step S30 is successful; and a spectacle lens manufacturing step S50 in which spectacle lenses are manufactured based on this design if the evaluation in the evaluation step S30 is successful.

[0039] The base eyeglass lens design step S10 is a work step that is currently generally performed at eyeglass retailers and the like. First, in a refraction (visual acuity) test step S11, the person (wearer) to be fitted with the eyeglasses undergoes a refraction test and visual acuity test similar to those performed at general eyeglass retailers. Then, in an interview step S12, the wearer is interviewed about the intended use of the eyeglasses, the frequency of use, and the importance of such use, in order to design lenses that suit the wearer's eyes. Then, distance information to a visual target (e.g., a computer screen) corresponding to the intended use is obtained (distance information acquisition step S13). The data for lens design thus obtained is sent to an eyeglass lens manufacturer, who then designs a base eyeglass lens based on the received data and obtains lens design data (base design step S20).

[0040] 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 from among them 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 object.

[0041] Next, in an evaluation step S30, an evaluation is made as to 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 a three-dimensional clear vision area, an evaluation step S32 for evaluating whether the calculated three-dimensional clear vision area matches the intended use, etc., and a judgment step S33 for deciding the next step to proceed to based on the evaluation in the evaluation step S32.

[0042] In step S31, which calculates the three-dimensional clear vision area, as described above with reference to FIGS. 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 greater along the line of sight G when looking through the eyeglass lens. The line of sight G is then moved within the visible range of the eyeglass lens, and the area AC(0.2) is integrated to calculate the three-dimensional clear vision area as shown in FIGS. 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 along 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. Examples of desired ranges include driving a car, watching television, using a computer, operating a mobile device, reading, performing detailed manual tasks, or a combination of these. It is also possible to set priorities for each purpose using a questionnaire, such as driving: 5, using a computer: 3, and reading: 2.

[0043] 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 is reselected or revised in this manner, the process returns to three-dimensional clear vision region calculation step S31, where a three-dimensional clear vision region is calculated based on this reselection or revision. Thereafter, the above steps are repeated from step S32.

[0044] By following the above steps, eyeglass lenses are manufactured based on eyeglass lens design data that passed the evaluation in step S32, making it possible to create eyeglass lenses that are optimally suited to the wearer's eyesight and intended use.

[0045] 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

1. A method for evaluating eyeglass lenses, comprising: a calculation step of calculating a three-dimensional clear vision area in a visual field seen through the eyeglass lenses of the eyeglasses when a wearer is wearing the eyeglasses; and an evaluation step of evaluating the performance of the eyeglass lenses based on the calculated three-dimensional clear vision area.

2. The method for evaluating eyeglass lenses according to claim 1, wherein in the calculation step, 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 eyeglass lens is calculated, and the predetermined position is moved within the visible range of the eyeglass lens to integrate the linear clear vision area, thereby calculating the three-dimensional clear vision area.

3. The method for evaluating eyeglass lenses according to claim 1, wherein in the calculation step, the visual field space seen through the eyeglass lens is defined by an up-down angle (φ) and a left-right angle (θ) covering the visible range of the eyeglass 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 eyeglass lens, and the three-dimensional clear vision area is expressed by three-dimensional polar coordinates (D, φ, θ), and the position within the clear vision area expressed by the three-dimensional polar coordinates (D, φ, θ) is integrated within the clear vision area to calculate the three-dimensional clear vision area.

4. The method for evaluating eyeglass lenses according to claim 1, wherein in the calculation step, the visual field space seen through the eyeglass lens is defined by the up-down angle (φ) and left-right angle (θ) covering the visible range of the eyeglass lens as seen from the wearer's eye, and the distance (r) from the wearer's eye to a position on a line extending through a predetermined position within the visible range of the eyeglass lens, and the three-dimensional clear vision area is expressed by three-dimensional polar coordinates (r, φ, θ), and the positions within the clear vision area expressed by the three-dimensional polar coordinates (r, φ, θ) are integrated within the clear vision area to calculate the three-dimensional clear vision area.

5. A method for evaluating eyeglass lenses as described in claim 1, wherein the three-dimensional clear vision area corresponds to a range in which the contrast value of an object viewed through the eyeglass lens by a wearer while wearing the eyeglasses is equal to or greater than a predetermined value.

6. The method for evaluating eyeglass lenses according to claim 5, wherein the range in which the contrast value is equal to or greater than a predetermined value is determined by MTF calculation.

7. A method for evaluating eyeglass lenses as described in claim 5, in which a plurality of contrast values ​​are used as the contrast values ​​defining the three-dimensional clear vision area, such as contrast values ​​that do not cause any problems in the readability of objects and contrast values ​​to the extent that a decrease in contrast is not noticeable, and the three-dimensional clear vision area is selected and set based on the judgment levels of such a plurality of contrast values.

8. The method for evaluating a spectacle lens according to claim 1, further comprising determining an equal-contrast surface in which the contrast values ​​are equal within the visible range of the spectacle lens, and defining the three-dimensional clear vision area using the equal-contrast surface.

9. 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.

10. The method for evaluating a spectacle lens according to claim 8, wherein in the evaluation step, the performance of the spectacle lens is evaluated by evaluating the three-dimensional clear vision area in combination with the position of the equal-contrast surface.

11. A method for evaluating eyeglass lenses as described in 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 within the predetermined area thus obtained.

12. The method for evaluating a spectacle lens according to claim 11, wherein the spectacle lens is a progressive power lens, and at least one of the distance portion, the progressive portion and the near portion of the bifocal spectacle lens is set to the predetermined range.

13. The method for evaluating eyeglass lenses according to claim 11, wherein the predetermined range is selected and set based on an MTF calculation of the progressive power lens.

14. A method for evaluating eyeglass lenses as described in claim 1, wherein in the evaluation step, the performance of the eyeglass lenses 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 a wearer is wearing the eyeglasses.

15. A method for designing a spectacle lens, comprising a design step of correcting and designing the spectacle lens based on the evaluation in the evaluation step according to any one of claims 1 to 14.

16. 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.

17. A method for manufacturing eyeglass lenses, comprising the step of manufacturing eyeglass lenses based on a design according to the design step recited in claim 15.

18. A method for manufacturing a spectacle lens, comprising the step of manufacturing a spectacle lens based on the selection made by said selecting step as recited in claim 16.

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