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

Abstract

The present invention pertains to a spectacle lens evaluation method comprising: a calculation step for calculating a three-dimensional clear vision region AC in a visual field space visible through a spectacle lens (10) of spectacles (1) in a state where a wearer wears the spectacles (1); a visible region detection step for detecting a visible region where the three-dimensional clear vision region AC and a visual object OBJ present in the visual field space overlap when the wearer views the visual object OBJ through the spectacle lens (10); and an evaluation step for evaluating the performance of the spectacle lens (10) on the basis of the detected visible region.

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 are suited to the eyes of the wearer. For this reason, it is first necessary to evaluate and test the wearer's vision. Prior art documents related to such evaluations and tests 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 in a visual field visible through the eyeglass lenses of the eyeglasses when a wearer is wearing the eyeglasses; a visible area detection step of detecting a visible area where the three-dimensional clear vision area overlaps with a visual object present in the visual field when the wearer views the visual object through the eyeglass lenses; and an evaluation step of evaluating the performance of the eyeglass lenses based on the detected visible area.

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

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

[0009] The method for manufacturing a spectacle lens according to the present invention includes a step of manufacturing a spectacle lens based on the modified design obtained in the design step.

[0010] The method for manufacturing a spectacle lens according to the present invention includes 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, by cutting a right-eye spectacle lens along a plane extending vertically at the center in the left-right direction, and showing the clear vision area seen through the right-eye spectacle lens in 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 showing 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. 8 is a schematic cross-sectional view showing a state in which a wearer is wearing eyeglasses, by cutting a right-eye spectacle lens along a plane extending vertically at the center in the left-right direction, and showing the clear vision area seen through the right-eye spectacle lens. 1 is a schematic side cross-sectional view of a right-eye spectacle lens cut along a plane extending vertically at the center in the horizontal direction when a wearer is wearing the glasses and facing straight ahead, showing the visible range where the clear vision region seen through the distance portion of the right-eye spectacle lens overlaps with the visual target. 2 is a schematic side cross-sectional view of a right-eye spectacle lens cut along a plane extending vertically at the center in the horizontal direction when a wearer is wearing the glasses and facing straight ahead, showing the visible range where the clear vision region seen through the distance portion of the right-eye spectacle lens overlaps with the visual target (the visual target is shown as a transparent object for the sake of explanation).12 is a schematic plan cross-sectional view showing the range visible through the distance portion of the right-eye spectacle lens when the wearer is wearing the glasses and facing forward, cut on a plane along arrow XII in Fig. 11, and showing the visible range where the distinct vision region visible through the distance portion of the right-eye spectacle lens and the visual target overlap; 13 is a schematic plan cross-sectional view showing the range visible through the distance portion of the right-eye spectacle lens when the wearer is wearing the glasses and facing forward and has turned his head to the right, and showing the visible range where the distinct vision region visible through the distance portion of the right-eye spectacle lens and the visual target overlap; 14 is a schematic side cross-sectional view showing the range visible through the distance portion of the right-eye spectacle lens when the wearer is wearing the glasses and facing forward, cut along a plane extending up and down through the horizontal center, and showing the visible range where the distinct vision region visible through the near portion of the right-eye spectacle lens and the visual target overlap; 15A and 15B are schematic side cross-sectional views of a right-eye spectacle lens cut along a plane extending vertically at the center in the left-right direction when a wearer wearing eyeglasses faces straight ahead and raises their head, showing the visible range where the distinct vision region seen through the near portion of the right-eye spectacle lens overlaps with the visual target. Also shown are schematic plan cross-sectional views of a right-eye spectacle lens cut along arrow XVI in Fig. 15A and 15B when a wearer wearing eyeglasses faces straight ahead and turns their head to the right, showing the visible range where the distinct vision region seen through the near portion of the right-eye spectacle lens overlaps with the visual target. 1 is a flowchart showing a series of steps for evaluating the performance of a spectacle lens using an evaluation method according to the present embodiment, correcting and designing the spectacle lens based on the evaluation, and manufacturing the spectacle lens based on the corrected 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 degree of overlap between the three-dimensional clear vision area and a visual target. 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 as shown in Figures 5 to 8 can be obtained. 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 a three-dimensional clear vision region AC as shown in Figures 5, 8, and 9, the angle in the up-down direction centered on the line of sight O shown in Figure 5 is defined as an up-down angle φ, the angle in the left-right direction centered on the line of sight O shown in Figures 7 and 8 is defined as a left-right angle θ, and the distance D (diopter) from the line of sight center O 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 used to display the distance in three-dimensional polar coordinates (r, φ, θ). Instead of FIG. 5, FIG. 6 shows an example of displaying the distance in three-dimensional polar coordinates (r, φ, θ). The three-dimensional display area is the same in FIG. 5 and FIG. 6, but the illustrated size differs significantly depending on whether it is diopters (D) or the actual distance r (m), as shown. In the following, the length in the line of sight direction will be described using a diagram in which the length is represented by 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] As can be seen from the fixed position of the spectacle lenses 10 in each figure, the above explanation shows the visual field when the wearer of the eyeglasses 1 does not move their head in a way that would move the position of the eyeglasses 1. Each clear vision field AC(A) to AC(C) shows the clear vision field that is generated when the wearer rotates only their eyeballs around the eye's center of rotation O and moves their line of sight within the lens field of the spectacle lenses 10 without moving their head.

[0030] 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.

[0031] 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 formula is just one example, and other calculation methods may be used, such as based on a position from the negative end of the contrast value C(1A) to a position from the positive end of the contrast value C(2A) to ... positive end of the contrast value C(2A) to a position from the negative end of the contrast value C(1A) to a position from the positive end of the contrast value C(2A) to a position from the positive end of the contrast value C(2A) to a position from the positive end of the contrast value C(2A) to a position from the negative end of the contrast value C(1A) to a position from the positive end of the contrast value C(2

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The three-dimensional clear vision area is calculated and set as described above, and lens performance is evaluated using the calculated and set three-dimensional clear vision area. This evaluation is performed based on the degree of three-dimensional overlap between the clear vision area and the visual target seen by the wearer of the eyeglasses through the eyeglass lenses, as will be described in detail below.

[0036] Objects that people visually view are located at various distances, both near and far, and a person with normal vision and sufficient accommodative power can see objects from far away to near by using the lens to adjust focus. When the accommodative power of the lens decreases due to aging or other reasons, eyeglasses are used to compensate for this. One element in evaluating the performance of eyeglass lenses is how well a person can see an object while wearing the eyeglasses. The evaluation method according to this embodiment detects how much of the object the clear vision area covers when viewed through the eyeglass lenses, i.e., the degree of overlap between the clear vision area and the object, and evaluates the performance of the eyeglass lenses based on this.

[0037] There are various visual targets, from distant objects to close objects, but the evaluation is performed using visual targets divided into the following positions.

[0038] (1) Distant Object: Visually inspected objects are those located between infinity and 5 m (0.0D to 0.2D), such as those required when driving a car. (2) Near-distant Object: Visually inspected objects are those located between 5 m and 2 m (0.2D to 0.5D), such as road signs, billboards, and station timetables. (3) Intermediate Distance Object: Visually inspected objects are those located between 2 m and 50 cm (0.5D to 2.0D), such as whiteboards and displays during meetings, people sitting opposite, televisions, and computer screens. (4) Close Distance Object: Visually inspected objects are those located between 50 cm and (2.0D or more), such as smartphones, newspapers, books, and computer keyboards.

[0039] When a wearer wears eyeglasses and views the above-mentioned object through the eyeglass lenses, the degree of overlap between the clear vision area and the visual target is detected, and the performance of the eyeglass lenses is determined based on this. However, eyeglass lenses are made for a limited range of viewing distances, such as for myopia, hyperopia, presbyopia, and progressive power lenses (also known as bifocals), and it is necessary to evaluate the degree of overlap with the visual target corresponding to the range of viewing distances.

[0040] Furthermore, with regard to the visual range, there are significant differences between the visual range when a person moves their eyes (eyeballs), the visual range when they move their head up, down, left, and right, and even when they combine eye and head movements. A reference document on such visual ranges is Clinical Ophthalmology, Vol. 71, No. 13, p. 1796, December 2017, which will be cited below. On page 1796 of this reference document, Figure 1 shows the visual field ranges corresponding to the up, down, left, and right movements of the eyeballs and the up, down, left, and right movements of the head. Based on this Figure 1, the following explanation is given regarding the relationship between the visual field angle and information reception characteristics.

[0041] (a) Discrimination visual field: The central visual field where visual functions such as visual acuity are excellent, within a range of 5° up, down, left and right. (b) Effective visual field: The area where information can be received instantly by eye movement alone, within a range of approximately 30° left and right, approximately 8° upward, and approximately 12° downward. (c) Stable gaze visual field: The area where information can be gazed upon comfortably by eye and head movement and where information can be received effectively, within a range of 60° to 90° left and right, 20° to 30° upward, and 25° to 40° downward.

[0042] In this embodiment, the spectacle lens is evaluated based on the "(b) useful visual field" and "(c) stable visual field" defined above. An example of this evaluation will be described below for eyeglasses 1 having the bifocal spectacle lens 10 described above. Progressive-power lenses, also known as bifocal eyeglasses, come in a variety of types, depending on the distance ranges set for the distance portion 11 (11R, 11L), which is the portion at the top of the spectacle lens for viewing relatively far objects, and the distances for the near portion 12 (12R, 12L), which is the portion at the bottom for viewing relatively close objects, as well as their width and arrangement on the lens. For example, there are bifocal eyeglasses in which distant objects are viewed through the distance portion 11 and intermediate or near objects are viewed through the near portion 12; so-called bifocal eyeglasses in which the distance portion 11 is designed to provide closer vision than bifocal eyeglasses; and eyeglasses called near-near eyeglasses in which the distance portion 11 is designed to provide even closer vision. In this way, there are various types of bifocal eyeglasses that allow the user to view a substantially distant or intermediate object through the distance portion 11 and an intermediate or near object through the near portion 12.

[0043] Here, an example of bifocal eyeglasses in which a distant object is viewed through the distance portion 11 and an intermediate-distance object is viewed through the near portion 12 will be described. First, a case in which an object (distant object) located at infinity to 5 m (0.0D to 0.2D) is used as the visual target (distant visual target OBJ1) will be described with reference to FIGS. 11 to 14. These figures show a case in which a person wearing eyeglasses 1 views distant visual target OBJ1 with their right eye EY (R) through eyeglass lens 10 (10R). FIG. 11 shows a visual field space similar to that shown in FIG. 5, showing an example of distant visual target OBJ1. This visual field space is the spatial region that can be visually observed when a wearer of eyeglasses 1 faces straight ahead, rotates only their eyeballs around the eye's center of rotation O without moving their head, and moves their line of sight within the lens region of eyeglass lens 10. This is referred to as the static visual field space. As can be seen from the fixed position of the eyeglass lenses 10 in FIG. 11, the visual field space is shown in a state where the wearer of the eyeglasses 1 does not move his / her head in a manner that would move the position of the eyeglasses.

[0044] 11 to 18 are shown as transparent objects for ease of explanation, and show the overlapping area of ​​the visual object with the three-dimensional clear vision area AC. In reality, the surface of the visual object that can be seen from the right eye EY(R) is the visible area, and evaluation is performed using this visible area.

[0045] The three-dimensional clear vision region AC in the stationary visual space shown in Figure 11, like Figure 5, has a distance portion clear vision region AC(A) seen through the distance portion 11R, a progressive portion clear vision region AC(B) seen through the progressive portion 13R, and a near portion clear vision region AC(C) seen through the near portion 12R. The three-dimensional clear vision region AC is a region within the stationary visual space, and is referred to as the stationary clear vision region AC. Figure 11 also shows an example of a distant vision target OBJ1 in a schematic shape, with the distance portion clear vision region AC(A) and the progressive portion clear vision region AC(B) partially overlapping with the distance portion vision target OBJ1. The overlapping portions are indicated by hatching, and include a distance portion visible region DA(A)1 overlapping with the distance portion clear vision region AC(A), and a progressive portion visible region DA(B)1 overlapping with the progressive portion clear vision region AC(B). Since these areas exist within the static visual field space and within the static clear vision area AC, they are also referred to as the distance portion static visible area DA(A)1 and the progressive portion static visible area DA(B)1.

[0046] FIG. 12 shows the state when the wearer tilts their head upward from the state shown in FIG. 11 . FIG. 12 shows the state in which the head is tilted upward by an angle φ1, and the central gaze GO(1) when looking straight ahead turns upward by an angle φ1, resulting in a line of sight indicated by the central gaze GO(2). As the head is tilted in this manner, the worn eyeglasses 1 move upward together with the head, moving from the spectacle lens 10(1) indicated by the dashed line to the spectacle lens 10(2) indicated by the solid line, as shown in FIG. 12 . As a result, the entire static visual field space tilts upward by an angle φ1, and the three-dimensional clear vision field area AC within this static visual field space also tilts upward. That is, as shown in FIG. 12 , the distance clear vision field AC(A), the progressive clear vision field AC(B), and the near clear vision field AC(C) rotate upward by an angle φ1 around the center O of the eye. The entire visual field space that moves in this way is called a dynamic visual field space, and the entire clear vision area AC that moves in conjunction with this is called a dynamic clear vision area.

[0047] Even if the head is tilted in this way, the position of the far-vision target OBJ1 does not change, and therefore the degree of overlap between the far-vision target OBJ1 and the distance-vision clear vision area AC(A), the progressive-vision clear vision area AC(B), and the near-vision clear vision area AC(C) changes. Therefore, the overlapping areas are, as shown by hatching in Fig. 12, a distance-vision visible area DA(A)2 overlapping with the distance-vision clear vision area AC(A), a progressive-vision visible area DA(B)2 overlapping with the progressive-vision clear vision area AC(B), and a near-vision visible area DA(C)2 overlapping with the near-vision clear vision area AC(C). These three regions, namely, the distance portion visible region DA(A)2, the progressive portion visible region DA(B)2, and the near portion visible region DA(C)2, exist within the static visual field space when the center of the line of sight is the central line of sight GO(2), and therefore are also referred to as the distance portion static visual region DA(A)2, the progressive portion static visual region DA(B)2, and the near portion static visual region DA(C)2.

[0048] When the head is tilted upward by angle φ1 in this way, the visible area changes from the distance portion stationary visible area DA(A)1 and progressive portion stationary visible area DA(B)1 to the distance portion stationary visible area DA(A)2, progressive portion stationary visible area DA(B)2, and near portion stationary visible area DA(C)2. The total amounts of overlap of the distance portion clear vision area AC(A), progressive portion clear vision area AC(B), and near portion clear vision area AC(C) with the far visual target OBJ1 during this head tilt movement are determined as the distance portion dynamic visible area DA(A)T1, progressive portion dynamic visible area DA(B)T1, and near portion dynamic visible area DA(C)T1.

[0049] The lens performance is evaluated based on the distance portion static visible area DA(A)1 and progressive portion static visible area DA(B)1, the distance portion static visible area DA(A)2, progressive portion static visible area DA(B)2 and near portion static visible area DA(C)2, and the distance portion dynamic visible area DA(A)T1, progressive portion dynamic visible area DA(B)T1 and near portion dynamic visible area DA(C)T1, which are obtained as described above. One method of this evaluation is to calculate these three-dimensional areas and compare them with the three-dimensional area of ​​the far-viewing target OBJ1 for evaluation. However, because what the right eye EY(R) sees through the spectacle lens 10(R) is the spectacle-side surface of the far-viewing target OBJ1, it is more appropriate to compare the surface areas of the above areas for evaluation instead of the three-dimensional areas. At this time, it is preferable to evaluate by comparing the area on the projection plane as seen from the right eye EY(R) rather than the actual surface area.

[0050] The three-dimensional clear vision area AC in the static visual field space shown in Figure 11 also extends in the left-right direction. This will be explained with reference to Figure 13, which shows a planar cross-section taken along arrow XII in Figure 11. Figure 13 shows a visual field similar to that shown in Figure 7, with a distance visual target OBJ1 shown as an example. This visual field space is a static visual field that can be viewed when a wearer of the eyeglasses 1 faces straight ahead, rotates only their eyeballs around the center of rotation O of the eye without moving their head, and moves their line of sight within the lens area of ​​the eyeglass lens 10. Figure 13 shows a planar cross-section of the distance portion clear vision area AC(A) seen through the distance portion 11R, which partially overlaps with the distance portion visual target OBJ1. This overlapping portion, i.e., the distance portion visible area DA(A)3 (also referred to as the distance portion static visual area DA(A)3), is indicated by hatching.

[0051] Figure 14 shows the state when the wearer tilts his or her head to the right from the position shown in Figure 13. Figure 14 shows the state in which the head is tilted to the right by an angle θ1, and the central gaze GO(1), which was facing straight ahead, turns to the right by an angle θ1, resulting in a gaze position indicated by the central gaze GO(3). As the head is tilted in this manner, the worn eyeglasses 1 move to the right along with the head, moving from the spectacle lens 10(1) indicated by the dashed line to the position of the spectacle lens 10(3) indicated by the solid line, as shown in Figure 14. As a result, the entire static visual field space tilts to the right by an angle θ1, and the three-dimensional clear vision field area AC within this static visual field space also tilts and moves to the right. That is, as shown in Figure 14, the distance clear vision area AC(A) rotates to the right by an angle θ1 around the center of rotation O of the eye.

[0052] Even if the head is tilted in this way, the position of the far-visible target OBJ1 does not change, and therefore the degree of overlap between the distance vision area AC(A) and the far-visible target OBJ1 changes. Therefore, the area where they overlap is the distance vision area DA(A)4 that overlaps with the distance vision area AC(A), as shown by hatching in Figure 14. This distance vision area DA(A)4 exists within the static visual field space when the center of the line of sight is the central line of sight GO(3), and therefore it is also referred to as the distance vision area DA(A)4.

[0053] When the head is tilted rightward by an angle θ1 in this way, the distance vision stationary visible area DA(A)3 changes to the distance vision stationary visible area DA(A)4. During this tilt movement, the total amount by which the distance vision clear vision area AC(A) overlaps with the far visual target OBJ1 is calculated as the distance vision dynamic visible area DA(A)T2.

[0054] The lens performance is evaluated based on the distance portion stationary visible area DA(A)3, distance portion stationary visible area DA(A)4, and distance portion dynamic visible area DA(A)T2 obtained as described above. This evaluation can be performed by, for example, calculating the volume of the distance portion stationary visible area DA(A)3, distance portion stationary visible area DA(A)4, and distance portion dynamic visible area DA(A)T2, and comparing this with the volume of the three-dimensional area of ​​the distance viewing target OBJ1. Furthermore, evaluation may be performed by comparing surface areas instead of volumes, or by comparing areas on the projection surface as seen from the right eye EY(R) instead of actual surface areas.

[0055] Next, the case where an object at close range is viewed as a visual target (near-distance visual target OBJ2) through the near portion 12R will be described with reference to FIGS. 15 to 18. The basic explanation for this case is the same as that for viewing a distant visual target OBJ1 at a distance through the distance portion 11R or the progressive portion 13R, and is similar to the explanation above. FIG. 15 shows a visual field space similar to that of FIG. 11, with a near-distance visual target OBJ2 shown here. This visual field space is a static visual field space that can be viewed when a wearer of the eyeglasses 1 faces straight ahead, rotates only the eyeballs around the center of rotation O of the eyes without moving the head, and moves the line of sight within the lens area of ​​the eyeglass lenses 10.

[0056] The three-dimensional clear vision region AC in the static visual field space shown in Fig. 15 has a distance portion clear vision region AC(A) seen through the distance portion 11R, a progressive portion clear vision region AC(B) seen through the progressive portion 13R, and a near portion clear vision region AC(C) seen through the near portion 12R, similar to Fig. 5. Fig. 15 also shows an example of a near-distance visual target OBJ2 in a schematic shape, where the near portion clear vision region AC(C) and the progressive portion clear vision region AC(B) partially overlap with the near-distance visual target OBJ2. As indicated by hatching, the near portion has a visible region DA(C)11 overlapping with the near portion clear vision region AC(C), and a visible region DA(B)11 overlapping with the progressive portion clear vision region AC(B). Since these regions exist within the static visual field space, they are also referred to as the near portion static visually recognizable region DA(C)11 and the progressive portion static visually recognizable region DA(B)11.

[0057] Figure 16 shows the state when the wearer tilts their head downward from the state shown in Figure 15. Figure 16 shows the state in which the head is tilted downward by an angle φ2, and the central gaze GO (11) when looking straight ahead turns downward by an angle φ2, resulting in a line of sight indicated by the central gaze GO (12). As the head is tilted in this manner, the worn eyeglasses 1 tilt downward together with the head, moving from the spectacle lens 10 (11) indicated by the dashed line to the spectacle lens 10 (12) indicated by the solid line, as shown in Figure 16. As a result, the entire static visual field space tilts downward by an angle φ2, and the three-dimensional clear vision field area AC within this static visual field space also tilts downward. That is, as shown in Figure 16, the distance clear vision field AC (A), the progressive clear vision field AC (B), and the near clear vision field AC (C) rotate downward by an angle φ2 around the center O of the eye.

[0058] Even if the head is tilted in this way, the position of the near-distance visual target OBJ2 does not change, and therefore the degree of overlap between the distance vision area AC(A), the progressive vision area AC(B), and the near vision area AC(C) and the far-distance visual target OBJ1 changes. The overlapping areas are, as shown by hatching in Fig. 16, a distance vision area DA(A)12 overlapping with the distance vision area AC(A), a progressive vision area DA(B)12 overlapping with the progressive vision area AC(B), and a near vision area DA(C)12 overlapping with the near vision area AC(C). These areas exist within the static visual field space when the center of the line of sight is the central line of sight GO(12), and are therefore also referred to as the distance portion static visible area DA(A)12, the progressive portion static visible area DA(B)12, and the near portion static visible area DA(C)12.

[0059] When the head is tilted downward by the angle φ2 in this manner, a stationary visibility-enabled area for distance vision DA(A)12 appears, and the stationary visibility-enabled area for progressive vision DA(B)11 and the stationary visibility-enabled area for near vision DA(C)11 change to the stationary visibility-enabled area for progressive vision DA(B)12 and the stationary visibility-enabled area for near vision DA(C)12. The total amounts by which the clear vision area for distance vision AC(A), the clear vision area for progressive vision AC(B), and the clear vision area for near vision AC(C) overlap with the near-distance visual target OBJ2 during this tilt movement of the head are determined as the dynamic visibility-enabled area for distance vision DA(A)T11, the dynamic visibility-enabled area for progressive vision DA(B)T11, and the dynamic visibility-enabled area for near vision DA(C)11.

[0060] The lens performance is evaluated based on the thus-obtained statically visible area DA(B)11 of the progressive portion and the near portion visible area DA(C)11, the statically visible area DA(A)12 of the distance portion, the statically visible area DA(B)12 of the progressive portion and the near portion visible area DA(C)12, the dynamic visible area DA(A)T11 of the distance portion, the dynamic visible area DA(B)T11 of the progressive portion and the dynamic visible area DA(C)11 of the near portion. This evaluation can be performed, for example, by calculating the three-dimensional volume of each area and comparing this with the volume of the far-viewing target OBJ1. Furthermore, instead of the volume, surface areas may be compared for evaluation, or instead of the actual surface areas, areas on the projection surface as seen from the right eye EY(R) may be compared for evaluation.

[0061] The three-dimensional clear vision area AC in the static visual field space shown in Figure 15 also extends in the left-right direction. This will be explained with reference to Figure 17, which shows a planar cross-section taken along arrow XVI in Figure 15. Figure 17 shows a visual field similar to that shown in Figure 7, with a near-distance visual target OBJ2 shown as an example. This visual field space is a static visual field that can be viewed when a wearer of the eyeglasses 1 faces straight ahead, rotates only their eyeballs around the center of rotation O of the eye without moving their head, and moves their line of sight within the lens area of ​​the eyeglass lens 10. Figure 17 shows a planar cross-section of the near clear vision area AC(C) seen through the near vision portion 12R, which partially overlaps with the near-distance visual target OBJ2. This overlapping portion, i.e., the near vision visible area DA(C)13 (also referred to as the near vision visible area DA(C)13), is indicated by hatching.

[0062] Figure 18 shows the state when the wearer tilts his or her head to the right from the position shown in Figure 17. Figure 18 shows the state in which the head is tilted to the right by an angle θ2, and the central gaze GO(11), which was facing straight ahead, turns to the right by an angle θ2, resulting in a gaze position indicated by the central gaze GO(13). As the head is tilted in this manner, the worn eyeglasses 1 move to the right along with the head, moving from the spectacle lens 10(11) indicated by the dashed line to the position of the spectacle lens 10(13) indicated by the solid line, as shown in Figure 18. As a result, the entire static visual field space tilts to the right by an angle θ2, and the three-dimensional clear vision field area AC within this static visual field space also tilts and moves to the right. That is, as shown in Figure 18, the near clear vision field AC(C) rotates to the right by an angle θ2 around the center O of the eye.

[0063] Even if the head is tilted in this way, the position of the near-distance visual target OBJ2 does not change, and therefore the degree of overlap between the near-distance clear vision area AC(C) and the near-distance visual target OBJ2 changes. Therefore, the area where they overlap is the near-distance visible area DA(C)14 that overlaps with the near-distance clear vision area AC(C), as shown by hatching in Figure 18. This near-distance visible area DA(C)14 exists within the static visual field space in a state where the center of the line of sight is the central line of sight GO(13), and therefore it is also referred to as the near-distance static visible area DA(C)14.

[0064] When the head is tilted rightward by an angle θ1 in this way, the near portion stationary visible area DA(C)13 changes to the near portion stationary visible area DA(C)14. During this tilt movement, the total amount by which the near portion clear vision area AC(C) overlaps with the near distance visual target OBJ2 is calculated as the near portion dynamic visible area DA(C)T12.

[0065] The lens performance is evaluated based on the near portion stationary visible area DA(A)13, the near portion stationary visible area DA(A)14, and the near portion dynamic visible area DA(A)T12 obtained as described above. This evaluation can be performed by, for example, calculating the volume, which is the three-dimensional area, of the near portion stationary visible area DA(A)13, the near portion stationary visible area DA(A)14, and the near portion dynamic visible area DA(A)T12, and comparing this volume with the volume of the near distance visual target OBJ2. Furthermore, instead of the volume, the surface area may be compared for evaluation, or instead of the actual surface area, the area on the projection plane as seen from the right eye EY(R) may be compared for evaluation.

[0066] In the above explanation, the dynamic visible area changes depending on the amount of head tilt, so the extent to which this tilt is tolerated is a major factor. The aforementioned reference, "Clinical Ophthalmology, Vol. 71, No. 13, p. 1796, December 2017," states, "(c) Stable gaze field: An area in which the wearer can gaze comfortably with eye and head movement and effectively receive information, ranging from 60° to 90° horizontally, 20° to 30° upward, and 25° to 40° downward." Based on this, the dynamic clear vision area is defined as the clear vision area within the visual field visible through the eyeglass lenses 10 when the wearer, while wearing the eyeglasses 1, rotates their head and eye movements up to 30° upward, 40° downward, and 45° left and right. It is preferable to further restrict the dynamic clear vision area to the dynamic visual field area within the visual field space visible through the eyeglass lenses when the wearer rotates their head and eye movements up to 20 degrees upward, 25 degrees downward, and 30 degrees to the left and right.

[0067] Thus, the stable visual field described in the literature can be considered to be a visual field that combines eye movement and head movement. In this case, the angle obtained by subtracting the eye rotation angle from the angle described above is the range of head movement. Here, the eye rotation angle can be considered to be "(b) effective visual field: horizontal 30°, upward 8°, downward 12°" described in the literature, and the angle obtained by subtracting these values ​​can be considered the head rotation angle. In this case, the dynamic visual field area within the visual space seen through the eyeglass lenses can be determined when the wearer rotates their head up to 22 degrees upward, 28 degrees downward, and 30 degrees to the left and right, or, in a slightly more restricted state, when the wearer rotates their head up to 12 degrees upward, 13 degrees downward, and 15 degrees to the left and right.

[0068] In the above description, the degree of overlap between the entire clear vision region AC and the visual targets OBJ1 and OBJ2 is evaluated. However, the degree of overlap between each of the distance vision region AC(A), the progressive vision region AC(B), and the near vision region AC(C) and the visual targets OBJ1 and OBJ2 may be evaluated separately. Furthermore, a predetermined range may be selected and set from the visible range of the eyeglass lens 10, and the degree of overlap between the clear vision region and the visual targets OBJ1 and OBJ2 within the set range may be evaluated. For example, in the near vision region AC(C), since astigmatism is small in the horizontal center portion as shown in FIG. 2A, the predetermined range may be set from the visible range that can be seen through this portion. Alternatively, a predetermined range may be selected and set based on the distance and size of the visual target, and the degree of overlap between the clear vision region and the visual targets OBJ1 and OBJ2 within this set range may be evaluated.

[0069] The performance of the spectacle lens can be evaluated using the evaluation method described above, and the design of the spectacle lens 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 can be obtained. This series of steps will be described with reference to FIG. 19.

[0070] As shown in FIG. 19 , this series of steps includes an information acquisition step S10 in which a vision test such as a refraction test is conducted 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 conducted 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 is unsuccessful; 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.

[0071] 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).

[0072] 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.

[0073] 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, a step S32 for detecting a static visible area from the overlap of the calculated clear vision area with a visual target in the static visual field space, and a step S33 for detecting a dynamic visible area that occurs when the head is moved from the static visible area. It also includes an evaluation step S34 for evaluating lens performance, etc. based on the detected static and dynamic visible areas, and a judgment step S35 for deciding the next step to proceed to based on the evaluation in the evaluation step S34.

[0074] 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 spectacle 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 spectacle lens. Then, the line of sight G is moved within the visible range of the spectacle lens, and the area AC(0.2) is integrated to calculate the three-dimensional clear vision area as shown in Figures 5 to 8. Next, based on the static visible area detected in step S32 and the dynamic visible area detected in step S33, it is evaluated whether the base spectacle lens design designed or selected in step S20 matches the wearer's intended use, etc. (step S34).

[0075] If the evaluation in step S35 is successful, the process proceeds from decision step S35 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 S35 is unsuccessful, the process proceeds from decision step S35 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 area calculation step S31, where a three-dimensional clear vision area is calculated based on this reselection or revision. Thereafter, the above steps are repeated from step S32.

[0076] 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.

[0077] 1 Pair of spectacle lenses 10 Spectacle lenses 10R Spectacle lenses for right eye 10L Spectacle lenses for left eye 11R, 11L Near portions for right eye and left eye 12R, 12L Distance portions for right eye and left eye 13R, 13L Progressive portions for right eye and left eye 15 Spectacle frame C Contrast value EY(R) Right eye AC Three-dimensional clear vision area AC AC (A) Distance clear vision area AC (B) Progressive clear vision area AC (C) Near clear vision area

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; a visible area detection step of detecting a visible area where the three-dimensional clear vision area overlaps with a visual object present in the visual field when the wearer views the visual object through the eyeglass lenses; and an evaluation step of evaluating the performance of the eyeglass lenses based on the detected visible area.

2. The method for evaluating eyeglass lenses according to claim 1, wherein in the calculation step, a three-dimensional clear vision area in a stationary visual field space visible through the eyeglass lenses when the wearer, while wearing the eyeglasses, moves his / her eyes without moving his / her head is calculated as a stationary clear vision area; in the visible area detection step, a stationary visible area where the stationary clear vision area and the visual object overlap when the wearer views the visual object present in the stationary visual field space through the eyeglass lenses is detected; and in the evaluation step, performance of the eyeglass lenses is evaluated based on the detected stationary visible area.

3. The method for evaluating eyeglass lenses according to claim 1, wherein in the calculation step, a three-dimensional clear vision area in a dynamic visual field space visible through the eyeglass lenses when the wearer, while wearing the eyeglass lenses, turns his / her head up and down and left and right and moves his / her eyes is calculated as a dynamic clear vision area; in the visible area detection step, a dynamic visible area where the dynamic clear vision area and the visual object overlap is detected when the wearer views the visual object present in the dynamic visual field space through the eyeglass lenses; and in the evaluation step, performance of the eyeglass lenses is evaluated based on the detected dynamic visible area.

4. A method for evaluating eyeglass lenses as described in claim 3, in which, with the wearer wearing the eyeglass lenses, a range of movement is set in each of the upward, downward, and left and right directions for each of the wearer's eye rotation angle and head movement angle, and the clear vision area within the visual field space visible through the eyeglass lenses is calculated as the dynamic visual field area.

5. A method for evaluating eyeglass lenses as described in claim 4, wherein the clear vision area within the visual field space visible through the eyeglass lenses is calculated as the dynamic visual field area when the wearer, while wearing the eyeglass lenses, rotates his / her head and eye movements up to 30 degrees upward, up to 40 degrees downward, and up to 45 degrees to the left and right.

6. A method for evaluating eyeglass lenses as described in claim 5, wherein the clear vision area within the visual field space visible through the eyeglass lenses is calculated as the dynamic visual field area when the wearer, while wearing the eyeglass lenses, rotates his / her head and eye movements up to 20 degrees upward, up to 25 degrees downward, and up to 30 degrees in each direction to the left and right.

7. A method for evaluating eyeglass lenses as described in claim 4, wherein the clear vision area within the visual field space visible through the eyeglass lenses is calculated as the dynamic visual field area when the wearer, while wearing the eyeglass lenses, rotates his / her head up to 22 degrees upward, up to 28 degrees downward, and up to 30 degrees in each direction to the left and right.

8. The method for evaluating eyeglass lenses according to claim 7, further comprising the step of calculating, as a dynamic visual field area, a clear vision area within a visual field space visible through the eyeglass lenses when the wearer, while wearing the eyeglass lenses, turns his / her head up to 12 degrees upward, up to 13 degrees downward, and up to 15 degrees in each direction to the left and right.

9. A method for evaluating eyeglass lenses as described in claim 1, wherein, in the calculation step, a linear clear vision area on a straight line extending from the wearer's eye through a specified position within the visible range of the eyeglass lens is calculated, and in the three-dimensional area calculation step, the specified position is moved within the visible range of the eyeglass lens, and the linear clear vision area calculated in the calculation step is integrated and displayed to determine the three-dimensional clear vision area.

10. A method for evaluating eyeglass lenses as described in claim 1, wherein, in the calculation step, the visible range of 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, in the volume calculation step, the positions within the clear vision area expressed by the three-dimensional polar coordinates (D, φ, θ) are integrated and displayed within the clear vision area to determine the three-dimensional clear vision area.

11. A method for evaluating eyeglass lenses as described in claim 1, wherein, in the calculation step, the visible range of 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 a distance (r) indicating a position on a 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 (r, φ, θ), and, in the volume calculation step, the positions within the clear vision area expressed by the three-dimensional polar coordinates (r, φ, θ) are integrated and displayed within the clear vision area to determine the three-dimensional clear vision area.

12. 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 by a wearer through the eyeglass lens while wearing the eyeglasses is equal to or greater than a predetermined value.

13. A method for evaluating eyeglass lenses as described in claim 12, in which a plurality of contrast values, such as a contrast value that does not cause any problems in the readability of an object and a contrast value to the extent that a decrease in contrast is not noticeable, are used as the contrast value defining 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.

14. The method for evaluating a spectacle lens according to claim 12, 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 region using the equal-contrast surface.

15. A method for evaluating eyeglass lenses as described in claim 1, comprising the steps of: selecting and setting a predetermined range from the visible range of the eyeglass lens; determining a three-dimensional clear vision area within the set range; and, in the evaluation step, evaluating the performance of the eyeglass lens based on the three-dimensional clear vision area within the predetermined range thus determined.

16. The method for evaluating a spectacle lens according to claim 15, wherein the spectacle lens is a progressive power lens, and at least one of a distance portion, a progressive portion and a near portion of the progressive power lens is set to the predetermined range.

17. The method for evaluating a spectacle lens according to claim 15, wherein a range in which the astigmatism distribution of the progressive power lens is small is set as the predetermined range.

18. A method for designing eyeglass lenses, comprising a design step of correcting the design of the eyeglass lenses based on the evaluation in the evaluation step according to any one of claims 1 to 17.

19. A method for designing 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 17.

20. A method for manufacturing a spectacle lens, comprising the step of manufacturing a spectacle lens based on a revised design according to the design step of claim 18.

21. A method for manufacturing a spectacle lens, comprising the step of manufacturing a spectacle lens based on the selection made by the selection step of claim 19.

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