Evaluation method, design method, selection method, and manufacturing method for spectacle lens

Abstract

An evaluation method for a spectacle lens is configured to comprise: a blur sensitivity information acquisition step for obtaining information on blur sensitivity of a wearer of spectacles; a calculation step for calculating a three-dimensional clear vision region AC in a visual field space visible to the wearer through a spectacle lens (10) of the spectacles (1) in a state where the spectacles (1) are worn by the wearer, while taking into account the sensitivity information acquired in the blur sensitivity information acquisition step; and an evaluation step for evaluating the performance of the spectacle lens on the basis of the three-dimensional clear vision region AC obtained in the calculation step.

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 vision. Prior art documents related to such evaluations and tests include Patent Documents 1, 2, and 3.

[0003] JP 2001-318344 A JP 2014-85575 A International Publication No. 2018 / 101015 A1

[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 blur sensitivity information acquisition step for obtaining information regarding the sensitivity of a wearer of eyeglasses to blur; a calculation step for calculating a three-dimensional clear vision area within the visual field visible through the eyeglass lenses of the eyeglasses when the wearer is wearing the eyeglasses, taking into account the sensitivity information obtained in the blur sensitivity information acquisition step; and an evaluation step for evaluating the performance of the eyeglass lenses based on the three-dimensional clear vision area obtained in the calculation step.

[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] Another spectacle lens evaluation method according to the present invention comprises: a blur sensitivity information acquisition step of obtaining information regarding the sensitivity of a spectacle wearer to blur; a calculation step of calculating a three-dimensional clear vision area in a visual field space visible through the spectacle lenses of the spectacle wearer while the spectacle wearer is wearing the spectacle, taking into account the sensitivity information obtained in the blur sensitivity information acquisition step; a visible area detection step of detecting a visible area where the three-dimensional clear vision area obtained in the calculation step overlaps with a visual object present in the visual field space when the wearer views the visual object through the spectacle lenses; and an evaluation step of evaluating the performance of the spectacle lens based on the detected visible area.

[0012] The method for designing a spectacle lens according to the present invention includes a design step for correcting the design of the spectacle lens based on the evaluation in the evaluation step of the other spectacle lens evaluation method described above.

[0013] The eyeglass lens selection method according to the present invention includes 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 of the other eyeglass lens evaluation method described above.

[0014] 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.

[0015] 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.

[0016] FIG. 1( a) is a conceptual diagram showing an aspect of an inspection according to an embodiment of a design method when an image to be presented is at a long distance, FIG. 1( b) is a conceptual diagram showing an aspect of the inspection when an image to be presented is at a medium distance, and FIG. 1( c) is a conceptual diagram showing an aspect of the inspection when an image to be presented is at a short distance. FIG. 2( a) is a diagram showing an original image before being processed into a blurred image, and FIG. 2( b) is a diagram showing an example of a blurred image. It is a conceptual diagram for explaining a method of creating a blurred image. It is a diagram showing an unblurred long-distance image to be shown to an inspection subject. It is a diagram showing an image for long-distance use with a medium degree of blur to be shown to an inspection subject. It is a diagram showing an image for long-distance use with a large degree of blur to be shown to an inspection subject. It is a diagram showing an image for close-distance use with an unblurred image to be shown to an inspection subject. It is a diagram showing an image for close-distance use with a medium degree of blur to be shown to an inspection subject. It is a diagram showing an image for close-distance use with a large degree of blur to be shown to an inspection subject. It is a table showing the relationship between the astigmatism power when a blurred image is produced and the corresponding MTF value calculated from the contrast of the blurred image. 13 is a schematic diagram showing eyeglasses having a pair of eyeglass lenses according to a first embodiment. It shows an example of an optical performance evaluation diagram for 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. 13, 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 visible 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 the eyeglasses, cut along a plane extending up and down through the center in the left-right direction of the spectacle lens for the right eye, and showing the clear vision area seen through the spectacle lens for the right eye in three-dimensional polar coordinates (r, φ, θ). 6 is a planar cross-sectional view showing a cross-section taken along arrow VII passing through the clear vision area AC(A) at the distance portion in FIG. 5, and showing the clear vision area within that cross-section. 7 is a planar cross-sectional view showing a cross-section taken along arrow VIII passing through the clear vision area AC(C) at the near portion in FIG. 5, and showing the clear vision area within that cross-section.1 is a graph showing the difference in change in contrast value C in directions differing by 90 degrees due to astigmatism. It is a schematic cross-sectional view showing a state in which a wearer is wearing eyeglasses, by cutting a spectacle lens for a right eye along a plane extending vertically at the center in the horizontal direction, and showing the clear vision area visible through the spectacle lens for the right eye. It is a flowchart showing a series of steps for evaluating the three-dimensional clear vision area of ​​a spectacle lens by the evaluation method according to the first embodiment, selecting and / or correcting the design of the spectacle lens based on this evaluation, and manufacturing the spectacle lens based on that design. It is a schematic side cross-sectional view showing a spectacle lens for a right eye in a state in which a wearer is wearing eyeglasses and facing forward, by cutting a spectacle lens for a right eye along a plane extending vertically at the center in the horizontal direction, and showing the visible range where the clear vision area visible through the distance portion of the spectacle lens for the right eye overlaps with the visual object in a second embodiment. 11 is a schematic side cross-sectional view showing 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 then raises their head, illustrating the visible range where the clear vision region seen through the distance portion of the right-eye spectacle lens overlaps with the visual target (for the sake of explanation, the visual target is shown as if it were a transparent object). FIG. 12 is a schematic plan cross-sectional view showing a right-eye spectacle lens cut along an arrow XII in FIG. 1 ... 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 the wearer is wearing the glasses and facing forward, showing the visible range where the clear vision region seen through the near portion of the right-eye spectacle lens and the visual target overlap. 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 the wearer is wearing the glasses and facing forward but has raised their head upward, showing the visible range where the clear vision region seen through the near portion of the right-eye spectacle lens and the visual target overlap.16 is a schematic planar cross-sectional view showing the range visible through the near portion of the right-eye spectacle lens when a wearer is wearing eyeglasses and facing straight ahead, cut on a plane along arrow XVI in FIG. 15 , 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. FIG. 17 is a schematic planar cross-sectional view showing the range visible through the near portion of the right-eye spectacle lens when a wearer is wearing eyeglasses and facing straight ahead and has turned their head to the right, 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. FIG. 18 is a flowchart showing a series of steps for evaluating the performance etc. of a spectacle lens by an evaluation method according to this embodiment, correcting and designing the spectacle lens based on this evaluation, and manufacturing the spectacle lens based on this corrected design.

[0017] Preferred embodiments of the present invention will be described below. One aspect of the present invention relates to a method for evaluating eyeglass lenses, and one of its features is that the evaluation is performed taking into account the sensitivity of the eyeglass wearer to blur. Therefore, first, the acquisition of information regarding the wearer's sensitivity to blur will be described.

[0018] FIG. 1 is a diagram showing an example of a blur sensitivity test performed on a wearer of eyeglass lenses. In the blur sensitivity test, information regarding the wearer W's sensitivity to blur in his or her visual field is tested. The sensitivity to blur is measured by creating a blurred image S by blurring an image of an object using various methods. The sensitivity to blur is expressed as the degree of blur that the wearer W can tolerate when viewing the blurred image S, or the degree of blur that the wearer W can perceive without discomfort. If the wearer W has a high sensitivity to blur, even an image with a low degree of blur is likely to cause discomfort (uncomfortable feeling), i.e., the range of acceptable blur levels is narrow. On the other hand, if the wearer W has a low sensitivity to blur, even an image with a high degree of blur is unlikely to cause discomfort (uncomfortable feeling), i.e., the range of acceptable blur levels is wide. In the following embodiment, an example will be described in which the wearer W measures the degree of blur that is acceptable in the blur sensitivity test. The image before blurring is referred to as the original image So.

[0019] In the blur sensitivity test, an examiner has a wearer W of the eyeglasses view a plurality of blurred images S and an original image So presented at a predetermined distance from the wearer W. The plurality of blurred images S are created by blurring the original image So to different degrees. The blurred images S and the original images So are displayed on a tablet terminal, a display of a personal computer (hereinafter referred to as a PC), or a printed material such as paper and presented to the wearer W. The blurred images S are preferably viewed with a visual acuity that allows the original images So to be clearly visible. After adjusting the corrective visual acuity of the wearer W using corrective lenses or the like as necessary, the blurred images S are presented and the blur sensitivity test is performed.

[0020] The inspector asks the wearer W, who is viewing the blurred image S, to answer verbally or by using an input device with buttons or the like whether the blurred image S is acceptable. From the answers of the wearer W about the multiple blurred images S, the inspector determines the degree of sensitivity to blur in the wearer W's visual field, expressed as a numerical value or the like according to a predetermined standard. This will be described in detail later, but the blurred image S is an image for sensitivity evaluation, which has been blurred to a degree corresponding to the magnitude of the aberration of the eyeglass lens.

[0021] Fig. 1(a) is a conceptual diagram of a blur sensitivity test in which a wearer W views a blurred image S presented at a position that is a long distance (2 m in this example) from the wearer W. In Fig. 1(a), the line of sight of the wearer W when viewing the blurred image S at a distance Df of 2 m with both eyes is schematically shown by a solid arrow. In a long-distance blur sensitivity test, the distance Df from the eyes of the wearer W to the blurred image S can be appropriately set to a distance of 1 m or more.

[0022] The numerical ranges of distances corresponding to the long distance and the short and medium distances described below may be changed as appropriate. The blur sensitivity test may be performed for each eye at each distance. The blurred image S presented in the long distance blur sensitivity test is preferably an image of letters, symbols, or text, or an image of an object that the wearer W views at a long distance in daily life or in a specific situation, created as the original image So. Examples of objects that can be viewed at a long distance include a television, a room or outdoor landscape, a blackboard or whiteboard with letters or text written on it, etc.

[0023] FIG. 1(b) is a conceptual diagram of a blur sensitivity test in which a wearer W views a blurred image S presented at a medium distance (80 cm in this example) from the wearer W. In FIG. 1(b), the line of sight of the wearer W when viewing the blurred image S at a distance Dm of 80 cm with both eyes is schematically shown by a solid arrow. In a medium-distance blur sensitivity test, the distance Dm from the wearer W's eyes to the blurred image S can be appropriately set to a distance of 50 cm or more and less than 1 m. The blurred image S presented in the medium-distance blur sensitivity test is preferably created using an original image So of an image of a character, symbol, or sentence, or an image of an object that the wearer W views at a medium distance in daily life or in a specific situation. A PC screen or the like can be appropriately used as the object viewed at a medium distance.

[0024] FIG. 1(c) is a conceptual diagram of a blur sensitivity test in which a wearer W views a blurred image S presented at a short distance (here, 30 cm) from the wearer W. In FIG. 1(c), the line of sight when the wearer W views the blurred image S at a distance Dn of 30 cm with both eyes is schematically shown by a solid arrow. In a short-distance blur sensitivity test, the distance Dn from the wearer W's eyes to the blurred image S can be appropriately set to a distance of 25 cm or more and less than 50 cm. The blurred image S presented in the short-distance blur sensitivity test is preferably created using an original image So as an image of a character, symbol, or sentence, or an image of an object that the wearer W views at close range in daily life or in a specific situation. Examples of objects viewed at close range include mobile phones such as smartphones, tablets, magazines, newspapers, etc.

[0025] FIG. 2 is a diagram illustrating an original image So and a blurred image S. FIG. 2(a) shows an original image So consisting of the letter "E." FIG. 2(b) shows multiple blurred images S created by blurring the original image So of FIG. 2(a) to different degrees. The blurred image S1 has slight distortion of the contours and is blurred to a small degree. The blurred image S2 has blurred contours to an extent that they are not clearly recognizable and is blurred to a medium degree. The blurred image S3 is generally unclear and is blurred to a large degree.

[0026] The blurred image S is a virtually created image of the original image So perceived when viewed through a refractive body such as an ocular optical system that generates astigmatism or a spectacle lens that generates astigmatism. The degree of astigmatism of such an ocular optical system or the degree of astigmatism of the refractive body corresponds to the degree of blur of the created blurred image S. Therefore, based on information regarding the sensitivity of the wearer W obtained for blurred images S corresponding to different degrees of blur, the three-dimensional clear vision region of the spectacle lens to be designed can be appropriately set to suit the wearer W.

[0027] 3 is a conceptual diagram for explaining a method for creating a blurred image S. In the method for creating the blurred image S, an original image So is placed at a position away from the front of the eyeball 90 by the distance (corresponding to the above-mentioned Df, Dm, and Dn) between the wearer W and the blurred image S when performing a blur sensitivity test, and a spectacle lens L is placed in the optical path from the original image So toward the retina of the eyeball 90, and ray tracing is performed from each point on the original image So. Calculations for ray tracing can be performed appropriately using a PC or the like.

[0028] In FIG. 3 , as examples of light rays to be ray-traced, a light beam F1 from the top edge of the original image So is represented by a dashed line, and a light beam F2 from the bottom edge of the original image So is represented by a solid line. In the example of FIG. 3 , due to refraction by the spectacle lens L and the ocular optical system within the eyeball 90, the light rays from the original image So converge behind the retina. In other words, the focal point is not on the retina. In this case, the image projected onto the retina will be blurred to the extent that it is out of focus. Using known ray-tracing calculations, it is possible to obtain the distribution of the amount of light from the original image So that reaches a projection plane B that is perpendicular to the optical axis of the ocular optical system and includes the intersection of the optical axis and the retina. Based on the distribution of the amount of light that reaches the projection plane B obtained by ray tracing, the distribution of the blurred image S (e.g., the distribution of brightness or, in the case of a printed image, the color density) is determined.

[0029] In the ray tracing model shown in Fig. 3, blurred images S with different degrees of blur can be created by appropriately changing the optical characteristics of the eyeglass lenses L, etc. Creating a blurred image S by changing the astigmatism, etc. of the eyeglass lenses L is also preferable in terms of obtaining a correspondence relationship between the degree of blur of the blurred image S and aberration.

[0030] When creating multiple blurred images for use in the blur sensitivity test, aberration is expressed as the amount of aberration of the spectacle lens or the amount of aberration of the eyeball. For example, the minimum aberration amount is 0D, and the maximum aberration amount is 1D to 3D, with any interval between these amounts, such as 0.1D, 0.25D, or 0.5D, being created. In the case of directional aberrations such as astigmatism, the angle of aberration is varied at any interval between 15° and 90° to create blurred images. It is also possible to combine multiple aberrations or spherical power errors within the above range, rather than a single aberration. Furthermore, when creating the blurred image S, ray tracing may be performed using an eyeball model constructed taking into account the distance to the object, the wearer W's age, the strength of accommodation, and the like. This allows for more precise creation of the blurred image S by taking into account changes in the eye's accommodation.

[0031] Next, a method for collecting information regarding the wearer's sensitivity to blur will be described. First, a plurality of blurred images S created by blurring an original image So to different degrees are presented at positions at short, medium, and long distances from the wearer W, and the wearer is allowed to view them. For example, a plurality of blurred images S are presented sequentially at a distance of 2 m from the wearer W, which is a long distance. Furthermore, a plurality of blurred images S are similarly presented sequentially at short and medium distances. The order in which the blurred images S with different degrees of blur are presented is not particularly limited, but it is preferable to present an image with a small degree of blur that is sufficiently acceptable to the wearer at least once every few images, so as to prevent the wearer from becoming accustomed to the blur.

[0032] Next, information regarding the wearer W's sensitivity to blur is obtained. The examiner asks the wearer W about the degree of blur that they can tolerate for each distance. Then, the examiner converts the wearer W's sensitivity to blur for each distance into a numerical value according to a predetermined standard and records it. After the blur sensitivity test for a certain distance is completed, the blur sensitivity test is then performed for a different distance.

[0033] To summarize the above, the blur sensitivity information acquisition method for collecting information regarding the sensitivity of a eyeglass wearer to blur comprises presenting a plurality of blurred images S created by applying different degrees of blur to an original image So at predetermined distances such as long distance, medium distance, and short distance from the wearer W to have the wearer W view the images, and acquiring information regarding the sensitivity to blur in the field of view of the wearer W. This makes it possible to appropriately acquire information regarding the sensitivity to blur for each of a plurality of distances.

[0034] The information regarding sensitivity to blur is information regarding whether or not it is acceptable for the wearer W to view the blurred image S. Each of the multiple blurred images S is created by ray tracing light that is emitted from the original image So and passes through the eyeglass lenses L, each of which generates a different aberration. This allows the creation of a blurred image S that more accurately represents the blur generated by a refractive body such as an eyeglass lens, and makes it possible to more accurately measure the sensitivity to blur in the visual field of the wearer W.

[0035] The acquisition of information regarding sensitivity to blur as described above will be explained below using a specific example that is closer to an actual test. In an actual test, examples of images shown to the test subject (the eyeglass wearer) for long distances include images of text, as shown in FIGS. 4 to 6. FIG. 4 is an unblurred image for long distances, FIG. 5 is an image for long distances with moderate blur, and FIG. 6 is an image for long distances with severe blur. In practice, long distance tests are performed by showing the wearer images with 17 levels of blur, i.e., images with varying degrees of blur in 18 levels, including the unblurred image. In all cases, the blurred images are created by adding astigmatism to unblurred images. The same applies to medium and short distances, and examples of close distance images are shown in FIGS. 7 to 9. FIG. 7 is an unblurred image for short distances, FIG. 8 is an image for short distances with moderate blur, and FIG. 9 is an image for short distances with severe blur. In practice, for close-range images, an examination at close range is performed by showing the wearer images with 17 levels of blur, that is, images with varying degrees of blur in 18 levels including an image without blur.

[0036] To be clear, as an example, the astigmatism (astigmatic power) of such an unblurred image and an image with 17 levels of blur is created in 0.10D steps from 0.00D (diopter) to 1.80D, as shown in Figure 10, resulting in 19 images. However, since the astigmatic power of 0.00D is an unblurred image and the astigmatic power of 1.80 is a gray image in which the characters are invisible, the blurred images are 17 images ranging from 0.01D to 1.70D. The average spatial frequency of the characters in these images is set to 10 cycles / degree. The contrast of each blurred image is then calculated, and the MTF corresponding to each astigmatic power value is determined, as shown in Figure 10. In this way, the astigmatic power of the blurred image identified in the blur sensitivity test can be converted to MTF contrast, making it possible to apply the blur sensitivity test results to the MTF clear vision area evaluation.

[0037] In the actual test, the subject (wearing glasses) is presented with images with varying degrees of blur in the above 18 stages for each of the long, medium, and short distances, and is asked to indicate which blurred image is acceptable. Those with a low tolerance for blur select a clear image (an image with a low astigmatism power), while those with a high tolerance for blur select an image with a large blur (an image with a large astigmatism power). The MTF value corresponding to the astigmatism power (D) of the image selected in this way is found from the table in Figure 10, and this MTF value is used in the MTF clear vision area evaluation described below.

[0038] After obtaining information regarding sensitivity to blur (MTF values ​​obtained in the blur sensitivity test) in the manner described above, the spectacle lenses are evaluated using these MTF values. First, as an example of this embodiment, FIG. 11 schematically shows eyeglasses 1, which are the subject of the spectacle lens evaluation method according to the present invention. As shown in FIG. 11 , the eyeglasses 1 are composed of a right-eye spectacle lens 10R used for the right eye EY(R), a left-eye spectacle lens 10L used for the left eye EY(L), and an eyeglass frame 15 having left and right mounting openings 15R and 15L into which both spectacle lenses 10R and 10L are mounted. In this embodiment, the right-eye spectacle lens 10R and the left-eye spectacle lens 10L may be collectively referred to simply as the spectacle lens 10. The spectacle lens 10 in this embodiment is a so-called progressive-power lens. The "up-down and left-right" positional relationships of the spectacle lens 10 refer to the positional relationships when the spectacle lens 10 is mounted in the spectacle frame 15 and used. That is, when a wearer wears the eyeglasses 1, the up / down and left / right directions as seen by the wearer are referred to as the up / down and left / right directions of the eyeglasses 1 and the eyeglass lenses 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.

[0039] 11 , 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.

[0040] 11 , the left-eye spectacle lens 10L has a left-eye distance portion 11L located at the top, a left-eye near portion 12L formed below the left-eye distance portion 11L, and a left-eye progressive portion 13L formed in the middle 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 the side closer to the left-eye distance portion 11L to the side closer to the left-eye near portion 12L.

[0041] 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."

[0042] The eyeglass lens 10 is manufactured by manufacturing a lens 10A designed as shown in Fig. 12 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. 12(A) and a power distribution (addition distribution) as shown in Fig. 12(B). Note that astigmatism is also generally referred to as astigmatic power (or astigmatic power), and astigmatism is sometimes referred to as astigmatic power (or astigmatic power) in this specification.

[0043] First Embodiment: A method for evaluating spectacle lenses according to a first embodiment 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 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 13 shows a state in which a wearer is wearing eyeglasses 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).

[0044] In FIG. 13 , 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 G1 changes, allowing the user to view objects in front of the eye 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 a person 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.

[0045] 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 13 as an example. Changes in contrast value along this line of sight G1 are shown in Figure 14. In Figure 14, 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.

[0046] 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. 14 , the contrast value C decreases depending on 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 also be expressed in terms of the actual length r (unit: m, etc.) instead.

[0047] As the position of the object viewed by the right eye EY(R) through the spectacle lens 10 moves forward and backward from the position at 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 larger the contrast value C, the clearer the object can be seen, and a region in the front-to-back direction on the line of sight G1 where the contrast value C is greater than a predetermined threshold is determined to be a linear clear vision region. For example, as shown in Figure 14, a contrast value C = 0.2 can be set as a threshold, and a region AC (0.2) where the contrast value is greater than this can be determined to be a linear clear vision region.

[0048] This clear vision area (linear clear vision area shown in FIG. 14 ) is the range within which the eyeglass wearer can clearly see the object being observed, and this area varies depending on the wearer's tolerance for blur. As described above, the blur sensitivity test is performed to determine the corresponding MTF contrast value from FIG. 10 based on the astigmatism power (astigmatism) of the blurred image selected as acceptable by the eyeglass wearer, and this value is used as a threshold to determine the clear vision area (linear clear vision area). Since people with a low tolerance for blur select blurred images with low astigmatism power, the MTF contrast value is, for example, 0.5. As a result, as shown in FIG. 14 , the contrast value C = 0.5 is set as the threshold, and the area AC (0.5) with a contrast value above this is the linear clear vision area for people with a low tolerance for blur. On the other hand, people with a high tolerance for blur select blurred images with high astigmatism power, and the MTF contrast value is, for example, 0.2. As a result, as shown in FIG. 14, a contrast value C=0.2 is set as a threshold, and an area AC (0.2) having a contrast value equal to or greater than this becomes a linear clear vision area for people with a high tolerance for blur.

[0049] In this way, the linear clear vision area AC is set in various ways using a contrast value as a threshold value based on the blur tolerance of the eyeglass wearer. For ease of explanation, however, we will use as an example a case where a contrast value C = 0.2 selected by a person with a high tolerance for blur is used as the threshold value, and the area AC (0.2) with a contrast value above this is set as the linear clear vision area.

[0050] 14 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. 14 will become a curve that has shifted in parallel in accordance with this widening range.

[0051] The linear clear vision area AC(0.2) on the line of sight G1 set in this manner is shown in Figure 13. 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 G1 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 15 to 18 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 15, 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.

[0052] When expressing a three-dimensional clear vision region AC as shown in Figures 15, 17, and 18, the angle in the up-down direction as shown in Figure 15 centered on the line of sight center O is defined as an up-down angle φ, and the angle in the left-right direction as shown in Figures 17 and 18 centered on the line of sight center O 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 15 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.

[0053] 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. 15, FIG. 16 shows an example of displaying the distance in three-dimensional polar coordinates (r, φ, θ). The three-dimensional clear vision area is the same in FIG. 15 and FIG. 16, but the illustrated size differs significantly depending on whether it is in 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).

[0054] The distance vision region AC(A), progressive vision region AC(B), and near vision region AC(C) shown in Fig. 15 are three-dimensional regions that also extend in the left-right direction of the spectacle lens 10. To illustrate this three-dimensional shape, Fig. 17 shows a planar cross section taken along arrow VII through the distance vision region AC(A) shown in Fig. 15, and Fig. 18 shows a planar cross section taken along arrow VIII through the near vision region AC(C). Figs. 17 and 18 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. 15.

[0055] First, we will explain the distance vision area AC(A) shown in Fig. 17. The distance vision area AC(A) is formed by the upper part of the spectacle lens 10, and as shown in Fig. 12(B), it has a lens configuration with a small diopter (negative) and a focus on a distant object. As shown in Fig. 12(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. 17 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.

[0056] Next, the near clear vision region AC(C) shown in FIG. 18 will be described. The near clear vision region AC(C) is formed by the lower portion of the spectacle lens 10, and as shown in FIG. 12(B), it has a lens configuration with a large (positive) power (addition power) and a near focus. As shown in FIG. 12(A), astigmatism (astigmatic refractive power) increases on both the left and right sides of the near clear vision region AC(C). In the absence of astigmatism, the arc-shaped area enclosed by the dashed-dotted lines LC1 and LC2 in FIG. 18 would be the clear vision region. However, in the near clear vision region AC(C), astigmatism increases rapidly toward both the left and right sides. Due to the influence of this rapidly increasing astigmatism, the clear vision region narrows rapidly 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 region disappears toward the left and right ends of the near clear vision region AC(C).

[0057] As can be seen from the fixed position of the spectacle lenses 10 in each figure, the above explanation shows the visual field space 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 created 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.

[0058] 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. 18 will be explained with reference to FIG. 19. FIG. 19 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. 19. In FIG. 19, 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.

[0059] 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

[0060] The contrast value C that defines the clear vision region is set according to the blur tolerance of the eyeglass wearer, as described above. That is, various criteria are used as threshold values, such as a standard contrast value that does not cause any problems with the readability of objects, a high contrast value that does not cause any noticeable decrease in contrast, and a low contrast value that just barely allows characters to be read. This makes it possible to perform an accurate evaluation based on the blur tolerance of the eyeglass wearer when carrying out the evaluation described below.

[0061] 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. 15, 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 clear vision area AC(A) and near clear vision area AC(C) shown in FIGS. 17 and 18 correspond to the height (angle φ) at the horizontal angle (angle θ), and the three-dimensional clear vision area is determined by the MTF.

[0062] 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, this is set according to the eyeglass wearer's tolerance for blur. For example, for a person with a low tolerance for blur, as shown in FIG. 14, a threshold contrast value C of 0.5 is used, and a region AC(0.5) where the contrast value is greater than this is set as the clear vision region. As shown in FIG. 20, the clear vision region AC(0.2) is the range sandwiched between two equal-contrast planes LA1(0.2) and LA2(0.2) where the contrast value C is 0.2, and the clear vision region AC(0.5) is the range sandwiched between two equal-contrast planes LA1(0.5) and LA2(0.5) where 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). Also, the equal contrast plane LA (FP) where the focus is the best and the contrast value C is the largest is located at the intermediate position.

[0063] 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. 13 , 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 G1 direction. For example, it is preferable to evaluate the determined three-dimensional clear vision area in relation to the position in the line of sight of the isocontrast planes LA1(0.2) and LA2(0.2) that define the clear vision area AC(0.2) and the isocontrast plane LA(FP) that is best in focus and has the largest contrast value C, and to evaluate the performance of the eyeglass lens.

[0064] 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 positional relationship in the direction of the line of sight G1 or its position relative to an equal-contrast surface. Each of the distance vision portion 11R, progressive power portion 13R, and near vision portion 12R of the eyeglass lens 10 can also be evaluated by combining its positional relationship in the direction of the line of sight G1 or its position relative to an equal-contrast surface. This allows the lens performance to be evaluated separately for each of the distance vision portion 11R, progressive power portion 13R, and near vision portion 12R. 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 a high MTF contrast value in the center of the near vision portion 12R, and lens performance during reading, for example, can be evaluated based on this area.

[0065] 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 well it covers what they want to see. 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, and then evaluate them accordingly. Information about these intended uses is obtained through interviews and questionnaires at opticians. This information is then sent to the manufacturer for design evaluation.

[0066] 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.

[0067] As shown in FIG. 21 , 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 S20 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 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.

[0068] The information acquisition 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) 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 acquired (distance information acquisition step S13). The data for lens design thus acquired is sent to an eyeglass lens manufacturer, who then designs a base eyeglass lens based on the received data and acquires lens design data (base design step S20).

[0069] 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.

[0070] 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.

[0071] In step S31, which calculates the three-dimensional clear vision area, as described above with reference to FIGS. 13 and 14 , the wearer wears the eyeglass lens 10 and calculates, for example, an area AC(0.2) where the contrast value C is 0.2 or greater along the line of sight G1 when looking through the eyeglass lens. The line of sight G1 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. 15 to 18 . 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 G1 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.

[0072] 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.

[0073] 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.

[0074] Second embodiment: Next, a method for evaluating eyeglass lenses according to a second embodiment will be described. In the second embodiment, lens performance is also evaluated using the three-dimensional clear vision area calculated and set as described above. This evaluation is performed based on the three-dimensional overlap between the clear vision area and the visual object seen by a wearer wearing eyeglasses through the eyeglass lenses, and will be described in detail below.

[0075] 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.

[0076] There are various visual targets, from distant objects to close objects, but the evaluation is performed using visual targets divided into the following positions.

[0077] (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.

[0078] 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.

[0079] 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.

[0080] (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.

[0081] 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.

[0082] 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. 22 to 25. 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. 22 shows a visual field space similar to that shown in FIG. 15, showing an example of distant visual target OBJ1. This visual field space is the spatial region that can be viewed 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 spatial region is referred to as the static visual field space. As can be seen from the fixed position of the eyeglass lenses 10 in FIG. 22, 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.

[0083] 22 to 29 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.

[0084] The three-dimensional clear vision region AC in the stationary visual space shown in Figure 22, like Figure 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. 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 22 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.

[0085] Figure 23 shows the state when the wearer tilts their head upward from the state shown in Figure 22. Figure 23 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 position of the spectacle lens 10(2) indicated by the solid line, as shown in Figure 23. 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 Figure 23, the distance clear vision field AC(A), progressive clear vision field AC(B), and 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.

[0086] 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. 23, 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.

[0087] 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.

[0088] 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 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.

[0089] The three-dimensional clear vision area AC in the static visual field space shown in Figure 22 also extends in the left-right direction, and this will be explained with reference to Figure 24, which shows a planar cross-section taken along arrow XII in Figure 22. Figure 24 shows a visual field space similar to that shown in Figure 17, with a distance visual target OBJ1 shown as an example. 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 eye's center of rotation O without moving the head, and moves the line of sight within the lens area of ​​the eyeglass lens 10. Figure 24 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.

[0090] Figure 25 shows the state when the wearer tilts his or her head to the right from the position shown in Figure 24. Figure 25 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 25. 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 25, the distance clear vision area AC(A) rotates to the right by an angle θ1 around the center of rotation O of the eye.

[0091] Even if the head is tilted in this way, the position of the far-viewing target OBJ1 does not change, and therefore the degree of overlap between the distance vision area AC(A) and the far-viewing 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 25. 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.

[0092] When the head is tilted rightward by the 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.

[0093] 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.

[0094] Next, the case where an object at a close distance is viewed as a visual target (near-distance visual target OBJ2) through the near portion 12R will be described with reference to FIGS. 26 to 29. 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. 26 shows a visual field space similar to that of FIG. 22, in which a near-distance visual target OBJ2 is shown. 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 region of the eyeglass lens 10.

[0095] The three-dimensional clear vision region AC in the static visual field space shown in Fig. 26 has, similarly to Fig. 15, 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. Fig. 26 also shows, in schematic form, an example of a near-distance visual target OBJ2 at a near distance, 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.

[0096] Figure 27 shows the state when the wearer tilts their head downward from the state shown in Figure 26. Figure 27 shows the state in which the head is tilted downward by an angle φ2, and the central gaze GO(11) when looking straight ahead is tilted 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 27. 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 27, the distance clear vision field AC(A), progressive clear vision field AC(B), and near clear vision field AC(C) rotate downward by an angle φ2 around the center O of the eye.

[0097] 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 vision target OBJ1 changes. The overlapping areas are, as shown by hatching in Fig. 27, 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.

[0098] When the head is tilted downward by the angle φ2 in this manner, the distance portion stationary visible area DA(A)12 appears, and the progressive portion stationary visible area DA(B)11 and near portion visible area DA(C)11 change to the progressive portion stationary visible area DA(B)12 and near portion visible area DA(C)12. The total amounts by which the distance portion clear vision area AC(A), progressive portion clear vision area AC(B), and near portion clear vision area AC(C) overlap with the near-distance visual target OBJ2 during this head tilt movement are determined as the distance portion dynamic visible area DA(A)T11, progressive portion dynamic visible area DA(B)T11, and near portion dynamic visible area DA(C)T11.

[0099] The lens performance is evaluated based on the thus-obtained statically visible area DA(B)11 of the progressive portion and the visible area DA(C)11 of the near portion, the statically visible area DA(A)12 of the distance portion, the statically visible area DA(B)12 of the progressive portion and the visible area DA(C)12 of the near portion, 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)T11 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, 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.

[0100] The three-dimensional clear vision area AC in the static visual field space shown in Figure 26 also extends in the left-right direction, and this will be explained with reference to Figure 28, which shows a planar cross-section taken along arrow XVI in Figure 26. Figure 28 shows a visual field space similar to that shown in Figure 17, with a near-distance visual target OBJ2 shown as an example. 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 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 28 shows a planar cross-section of the near clear vision area AC(C) seen through the near vision zone 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.

[0101] Figure 29 shows the state when the wearer tilts his or her head to the right from the position shown in Figure 28. Figure 29 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 29. 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 29, the near clear vision field AC(C) rotates to the right by an angle θ2 around the center O of the eye.

[0102] 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 29. 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.

[0103] When the head is tilted rightward by the angle θ1 in this way, the near portion static visible area DA(C)13 changes to the near portion static 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.

[0104] 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 of 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 with the volume of the near distance visual target OBJ2. Furthermore, evaluation may be performed by comparing surface areas instead of volumes, or by comparing areas on the projection plane as seen from the right eye EY(R) instead of actual surface areas.

[0105] 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.

[0106] 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. In a slightly more restricted state, the dynamic visual field area can be determined when the wearer rotates their head up to 12 degrees upward, 13 degrees downward, and 15 degrees to the left and right.

[0107] 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), as shown in FIG. 12(A), the astigmatism is small in the horizontal center portion, so 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.

[0108] 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.

[0109] As shown in FIG. 30 , 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 S20 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.

[0110] The information acquisition 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) 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 acquired (distance information acquisition step S13). The data for lens design thus acquired is sent to an eyeglass lens manufacturer, who then designs a base eyeglass lens based on the received data and acquires lens design data (base design step S20).

[0111] 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.

[0112] 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.

[0113] In step S31, which calculates the three-dimensional clear vision area, as described above with reference to Figures 13 and 14, 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 G1 when looking through the spectacle lens. Then, the line of sight G1 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 15 to 18. 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 20 matches the wearer's intended use, etc. (step S34).

[0114] 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 way, 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.

[0115] 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.

[0116] 1 Pair of spectacle lenses 10 Spectacle lenses 10R Spectacle lenses for right eye 10L Spectacle lenses for left eye 11R, 11L Distance parts for right eye and left eye 12R, 12L Near vision parts for right eye and left eye 13R, 13L Progressive parts 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 blur sensitivity information acquisition step for obtaining information regarding the sensitivity of a wearer of eyeglasses to blur; a calculation step for calculating a three-dimensional clear vision area within the visual field seen through the eyeglass lenses of the eyeglasses when the wearer is wearing the eyeglasses, taking into account the sensitivity information obtained in the blur sensitivity information acquisition step; and an evaluation step for evaluating the performance of the eyeglass lenses based on the three-dimensional clear vision area obtained in the calculation step.

2. The method for evaluating eyeglass lenses according to claim 1, wherein the blur sensitivity information acquisition step comprises: a viewing step of presenting a plurality of blurred images created by blurring an original image to different degrees and having the wearer view the images; and an information acquisition step of acquiring information regarding the wearer's sensitivity to blur based on the viewing results of the viewing step.

3. The method for evaluating eyeglass lenses according to claim 2, wherein the information regarding sensitivity to blur is information regarding whether or not the wearer can tolerate viewing the blurred image.

4. The method for evaluating eyeglass lenses according to claim 2, wherein each of the plurality of blurred images is created by ray tracing light that is emitted from the original image and passes through a refractive body that generates a different aberration.

5. A method for evaluating eyeglass lenses according to claim 2, wherein the plurality of blurred images are each created based on a point spread function obtained by tracing rays of light as they exit from a point at a predetermined distance from the retina, pass through a plurality of refractive bodies that generate different aberrations, and enter the retina.

6. 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 predetermined position within the visible range of the eyeglass lens is obtained taking into account the sensitivity information acquired in the blur sensitivity information acquisition step, and the predetermined position is moved within the visible range of the eyeglass lens and the linear clear vision area is integrated to calculate the three-dimensional clear vision area.

7. The method for evaluating eyeglass lenses according to claim 1, wherein in the calculation step, the visual field space visible 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 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.

8. 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 vertical angle (φ) and horizontal angle (θ) covering the visible range of the eyeglass lens as seen from the eye of the wearer, and the distance (r) from the eye of the wearer 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.

9. 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 seen through the eyeglass lens by a wearer wearing the eyeglasses is greater than or equal to a predetermined value, taking into account the sensitivity information acquired in the blur sensitivity information acquisition step.

10. The method for evaluating eyeglass lenses according to claim 9, wherein the range in which the contrast value is equal to or greater than a predetermined value is determined by MTF calculation.

11. A method for evaluating eyeglass lenses as described in claim 9, in which the contrast value defining the three-dimensional clear vision area is determined by taking into account the sensitivity information acquired in the blur sensitivity information acquisition step, and using a plurality of contrast values, such as a contrast value that does not cause any problems with the readability of the object and a contrast value 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.

12. The method for evaluating eyeglass lenses according to claim 1, wherein an equal-contrast plane where the contrast values ​​are equal is found within the visible range of the eyeglass lens, and the three-dimensional clear vision region is defined using the equal-contrast plane.

13. 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.

14. The method for evaluating eyeglass lenses according to claim 12, wherein in the evaluation step, the performance of the eyeglass lenses is evaluated by evaluating the three-dimensional clear vision area in combination with the position of the equal-contrast surface.

15. A method for evaluating eyeglass lenses, comprising: a blur sensitivity information acquisition step for obtaining information regarding the sensitivity of a wearer of eyeglasses to blur; a calculation step for calculating a three-dimensional clear vision area in a visual field visible through the eyeglass lenses of the eyeglasses while the wearer is wearing the eyeglasses, taking into account the sensitivity information obtained in the blur sensitivity information acquisition step; a visible area detection step for detecting a visible area where the three-dimensional clear vision area obtained in the calculation step 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 for evaluating the performance of the eyeglass lenses based on the detected visible area.

16. A method for evaluating eyeglass lenses according to claim 15, wherein in the calculation step, a three-dimensional clear vision area in a static 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 the static clear vision area; in the visible area detection step, a static visible area where the static clear vision area and the visual object overlap is detected when the wearer views the visual object present in the static visual field space through the eyeglass lenses; and in the evaluation step, performance of the eyeglass lenses is evaluated based on the detected static visible area.

17. A method for evaluating eyeglass lenses according to claim 15, 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.

18. A method for evaluating eyeglass lenses as described in claim 17, wherein, with the wearer wearing the eyeglass lenses, movement ranges are set in the upward, downward, and left-right directions for each of the wearer's eyeball 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.

19. A method for evaluating eyeglass lenses as described in claim 1 or 15, 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 determined, and the performance of the eyeglass lens is evaluated based on the three-dimensional clear vision area within the predetermined area thus determined.

20. The method for evaluating eyeglass lenses according to claim 19, wherein the eyeglass lenses are progressive power lenses, and at least one of the distance portion, progressive portion and near portion of the bifocal eyeglass lenses is set to the predetermined range.

21. The method for evaluating eyeglass lenses according to claim 20, wherein the predetermined range is selected and set based on an MTF calculation of the progressive power lens.

22. A method for evaluating eyeglass lenses according to claim 1 or 15, 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 the visual field visible through the eyeglass lenses of the eyeglasses when the wearer is wearing the eyeglasses.

23. A method for designing eyeglass lenses, comprising a design step of correcting and designing the eyeglass lenses based on the evaluation in the evaluation step according to claim 1 or 15.

24. 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 as set forth in claim 1 or 15.

25. A method for manufacturing eyeglass lenses, comprising the step of manufacturing eyeglass lenses based on a design according to the design step of claim 23.

26. A method for manufacturing an eyeglass lens, comprising the step of manufacturing an eyeglass lens based on the selection made by the selecting step according to claim 24.

Images