Method for evaluating sensitivity and method for manufacturing a pair of spectacle lenses

Abstract

According to the present invention, a reference blurred image (Cp) is viewed with one (e.g., the right eye) among both eyes, blurred images (Cp+1, Cp+2, …) are viewed with the other eye (e.g., the left eye), and information about sensitivity is acquired with respect to the difference between blur amounts of the blurred images (Cp+1, Cp+2, …) viewed with the other eye and the reference blurred image (Cp) viewed with the one eye. In addition, the reference blurred image (Cp) is viewed with the other eye, the blurred images (Cp+1, Cp+2, …) are viewed with the one eye, and information about sensitivity is acquired with respect to the difference between blur amounts of the blurred images (Cp+1, Cp+2, …) viewed with the one eye and the reference blurred image (Cp) viewed with the other eye.

Description

Technical Field

[0001] The present invention relates to a method for evaluating sensitivity and a method for manufacturing a pair of spectacle lenses.

Background Art

[0002] In binocular vision, it is known that due to the effect called binocular load (also called binocular summation), the contrast sensitivity becomes higher and the visual acuity improves compared to monocular vision. In a progressive power lens, which is a type of spectacle lens (see, for example, Patent Document 1), in the distance vision part having a refractive power suitable for distance vision, by overlapping the ranges where both eyes can see clearly (the range with small aberration), an object can be seen more clearly by binocular vision. However, there are individual differences in the effect called binocular load, and it is necessary to design the spectacle lens according to the sensitivity of the wearer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] A method for evaluating sensitivity according to one aspect of the present invention includes causing an image to be visually recognized in the right eye and the left eye with different amounts of defocus respectively, and obtaining information regarding the sensitivity to the difference in the amount of defocus of the images visually recognized in the right eye and the left eye.

[0005] A method for manufacturing a pair of spectacle lenses according to another aspect of the present invention is a method for manufacturing a pair of spectacle lenses comprising a right-eye spectacle lens used for the right eye and a left-eye spectacle lens used for the left eye, comprising: causing the right eye and the left eye to view an image with different amounts of blur; obtaining information on sensitivity to the difference in the amount of blur of the images viewed by the right eye and the left eye, respectively; designing the right-eye spectacle lens and the left-eye spectacle lens based on the information on sensitivity to the difference in the amount of blur; and manufacturing the right-eye spectacle lens and the left-eye spectacle lens based on the design. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic diagram showing a pair of spectacle lenses according to this embodiment. [Figure 2] This is a plan view of a pair of eyeglass lenses. [Figure 3] This is the Order Board for Eyeglass Lens Ordering and Receiving Systems. [Figure 4] This flowchart shows the manufacturing process for a pair of eyeglass lenses. [Figure 5] This figure shows an example of an order screen. [Figure 6] (A) is a diagram showing the original image before it was processed to create a blurred image, and (B) is a diagram showing an example of a blurred image. [Figure 7] This is a block diagram of the evaluation device. [Figure 8] This is a flowchart showing the flow of the sensitivity assessment method. [Figure 9] This is a conceptual diagram illustrating an example of how to assess sensitivity. [Figure 10] This is a flowchart showing the process for designing eyeglass lenses. [Figure 11] (A) is a diagram showing the distribution of astigmatism in an eyeglass lens when designed under the first lens design condition, (B) is a diagram showing the distribution of astigmatism in an eyeglass lens when designed under the second lens design condition, and (C) is a diagram showing the distribution of astigmatism in an eyeglass lens when designed under the third lens design condition. [Figure 12] This graph compares the magnitude of astigmatism in the distance vision portion of eyeglass lenses under different lens design conditions. [Figure 13] This graph shows the magnitude of astigmatism in the distance vision portion of an eyeglass lens when designed under the first lens design condition. [Figure 14] This graph shows the magnitude of astigmatism in the distance vision portion of an eyeglass lens when designed under the second lens design condition. [Figure 15] This is a conceptual diagram illustrating a variation used to evaluate sensitivity. [Modes for carrying out the invention]

[0007] Preferred embodiments of the present invention will be described below. Figures 1 and 2 schematically show a pair of spectacle lenses 1 according to this embodiment. As shown in Figures 1 and 2, the pair of spectacle lenses 1 consists of a right-eye spectacle lens 10R used for the right eye ER and a left-eye spectacle lens 10L used for the left eye EL. In this embodiment, the right-eye spectacle lens 10R and the left-eye spectacle lens 10L may be collectively referred to simply as spectacle lens 10. Spectacle lens 10 is also called a progressive power lens. Furthermore, the positional relationships of "upper part," "lower part," etc., in spectacle lens 10 refer to the positional relationships when spectacle lenses are worn after being processed for use as eyeglasses. Furthermore, the vertical positional relationship in spectacle lens 10 shall coincide with the vertical positional relationship on the plane of paper in Figures 1 and 11.

[0008] As shown in Figure 1, the right eye spectacle lens 10R has a right eye distance vision section 11R, a right eye near vision section 12R formed at a different position from the right eye distance vision section 11R, and a right eye progressive section 13R formed between the right eye distance vision section 11R and the right eye near vision section 12R. For example, the right eye distance vision section 11R is formed at the top of the right eye spectacle lens 10R, the right eye near vision section 12R is formed at the bottom of the right eye spectacle lens 10R, and the right eye progressive section 13R is formed in the middle of the right eye spectacle lens 10R. The right eye distance vision section 11R has refractive power suitable for distance vision. The right eye near vision section 12R has refractive power suitable for near vision. The progressive section 13R for the right eye is designed so that the refractive power changes continuously from the refractive power suitable for distance vision to the refractive power suitable for near vision as you move from the right eye distance section 11R towards the right eye near section 12R. In this embodiment, the numerical value representing the refractive power may be expressed as "power" (unit: diopter (D)).

[0009] As shown in Figure 1, the left eye spectacle lens 10L has a left eye distance vision section 11L, a left eye near vision section 12L formed at a different position from the left eye distance vision section 11L, and a left eye progressive section 13L formed between the left eye distance vision section 11L and the left eye near vision section 12L. For example, the left eye distance vision section 11L is formed at the top of the left eye spectacle lens 10L, the left eye near vision section 12L is formed at the bottom of the left eye spectacle lens 10L, and the left eye progressive section 13L is formed in the middle of the left eye spectacle lens 10L. The left eye distance vision section 11L has refractive power suitable for distance vision. The left eye near vision section 12L has refractive power suitable for near vision. The progressive section 13L for the left eye is designed so that the refractive power changes continuously from the refractive power suitable for distance vision to the refractive power suitable for near vision as you move from the left eye distance section 11L towards the left eye near section 12L.

[0010] As can be seen from the line of sight SR1 of the right eye ER and the line of sight SL1 of the left eye EL in Figure 2, when the wearer W of the pair of spectacle lenses 1 views the right side of a distant object OB, he uses the temporal portion of the right eye spectacle lens 10R (right eye distance vision portion 11R) and the nasal portion of the left eye spectacle lens 10L (left eye distance vision portion 11L). As can be seen from the line of sight SR2 of the right eye ER and the line of sight SL2 of the left eye EL in Figure 2, when the wearer W of the pair of spectacle lenses 1 views the left side of a distant object OB, he uses the nasal portion of the right eye spectacle lens 10R (right eye distance vision portion 11R) and the temporal portion of the left eye spectacle lens 10L (left eye distance vision portion 11L).

[0011] In eyeglass lenses 10, also known as progressive power lenses, astigmatism occurs because the refractive power changes depending on the part of the lens. To address this, the way objects appear through the eyeglass lenses 10 is improved by changing the distribution of astigmatism through design. For example, in the distance vision section 11R for the right eye and the distance vision section 11L for the left eye, the distribution of astigmatism is changed between the temporal and nasal parts to alter the degree of blurring in the right eye ER and the left eye EL when viewing a distant object OB. However, there are individual differences in the degree of blurring between the right eye ER and the left eye EL that is acceptable for the wearer W to see with both eyes. In this embodiment, during manufacturing, the wearer W's sensitivity to the difference in the degree of blurring between the right eye ER and the left eye EL is evaluated to design the eyeglass lenses 10 to suit the wearer W. Hereafter, the degree of blurring may be referred to as the amount of blur.

[0012] Next, a spectacle lens ordering and receiving system for manufacturing a pair of spectacle lenses 1 according to this embodiment will be described. Figure 3 shows the spectacle lens ordering and receiving system 50. As shown in Figure 3, this spectacle lens ordering and receiving system 50 is configured to include an ordering device 60 installed in an optician (ordering party), an order receiving device 70, a processing machine control device 80, and a spectacle lens processing machine 85, all installed in a lens manufacturer. The ordering device 60 and the order receiving device 70 are connected to each other via a network 90, such as the Internet. The processing machine control device 80 is connected to the order receiving device 70, and the spectacle lens processing machine 85 is connected to the processing machine control device 80. Although only one ordering device 60 is shown in Figure 3 for illustrative purposes, in reality, multiple ordering devices 60 installed in multiple opticians are connected to the order receiving device 70.

[0013] The ordering device 60 is a computer that processes orders for eyeglass lenses 10. The ordering device 60 includes a control unit 61, a storage unit 65, a communication unit 66, a display unit 67, and an input unit 68. The control unit 61 controls the ordering device 60 by executing a program stored in the storage unit 65. The control unit 61 has an order processing unit 62 that processes orders for eyeglass lenses 10. The communication unit 66 communicates with the order receiving device 70 via the network 90. ​​The display unit 67 is configured using a display device such as a CRT or liquid crystal display. The display unit 67 displays an order screen for inputting information (order information) about the eyeglass lenses to be ordered. The input unit 68 is configured using, for example, a mouse or keyboard. For example, order information corresponding to the contents of the order screen is input via the input unit 68. The display unit 67 and the input unit 68 may be integrated using a touch panel or the like.

[0014] The order receiving device 70 is a computer that performs order receiving processing, design processing, arithmetic processing of optical performance, etc. of the spectacle lens 10. The order receiving device 70 includes a control unit 71, a storage unit 75, a communication unit 76, a display unit 77, and an input unit 78. The control unit 71 controls the order receiving device 70 by executing a program stored in the storage unit 75. The control unit 71 includes an order receiving processing unit 72 that performs order receiving processing of the spectacle lens 10 and a design unit 73 that performs design processing of the spectacle lens 10. The storage unit 75 stores various data for spectacle lens design in a readable manner. The communication unit 76 communicates with the ordering device 60 via the network 90. Also, the communication unit 76 communicates with the processing machine control device 80. The display unit 77 is configured using a display device such as a CRT or a liquid crystal display. The display unit 77 displays the design result, etc. of the spectacle lens 10. The input unit 78 is configured using, for example, a mouse or a keyboard. Note that the display unit 77 and the input unit 78 may be integrally configured by a touch panel or the like.

[0015] Next, referring to FIG. 4, the procedure for manufacturing and providing a pair of spectacle lenses 1 using the spectacle lens order receiving and ordering system 50 will be described. FIG. 4 is a flowchart showing the flow until a pair of spectacle lenses 1 are manufactured and provided. Note that the left side of FIG. 4 shows the procedure performed on the optician side, and the right side of FIG. 4 shows the procedure performed on the lens manufacturer side. The orderer evaluates the sensitivity of the wearer (step ST11). The method for evaluating sensitivity will be described in detail later.

[0016] Next, the orderer causes the display unit 67 of the ordering device 60 to display an order screen and inputs order information via the input unit 68 (step ST12). At this time, the orderer determines the order information of the spectacle lenses to be ordered, including information regarding the sensitivity to the difference in defocus amount between both eyes, which was obtained when evaluating the sensitivity of the wearer.

[0017] Fig. 5 shows an example of an order screen 100. In the lens information item 101, items related to the lens order diopter such as the product name of the lens to be ordered, the spherical diopter (S diopter), the astigmatic diopter (C diopter), the astigmatic axis, and the addition are input. The processing specification information item 102 is used when specifying the outer diameter of the lens to be ordered or when specifying the arbitrary center thickness. The coloring information item 103 is used when specifying the color of the lens. The fitting point (FP) information 104 inputs the position information of the eyes of the wearer W. PD represents the interpupillary distance. In the frame information item 105, the frame model name, the frame type, etc. are input. In the sensitivity information item 106, as information related to the sensitivity to the difference in the amount of blur between both eyes obtained when evaluating the sensitivity of the wearer, a numerical value indicating the strength of the sensitivity to blur is input. In the example shown in Fig. 5, the strength of the sensitivity to blur is represented by numerical values in 10 levels for the difference in the degree of blur of the right eye with respect to the left eye and the difference in the degree of blur of the left eye with respect to the right eye, respectively (the difference in the degree of blur of the right eye with respect to the left eye is represented as "5", and the difference in the degree of blur of the left eye with respect to the right eye is represented as "4"). Also, the strength of the sensitivity to blur is defined such that the greater the number, the stronger the sensitivity to blur.

[0018] Note that the sensitivity to blur may be represented such that the smaller the sensitivity to blur, the larger the numerical value, or it may be represented by symbols instead of numerical values. As long as the sensitivity to blur can be represented and communicated according to a predetermined standard, the method is not particularly limited.

[0019] When the ordering party enters information into each item on the order screen 100 shown in Figure 5 and clicks the submit button (not shown), the order processing unit 62 of the order device 60 acquires the information (order information) entered in each item on the order screen 100. The order device 60 transmits the order information acquired by the order processing unit 62 to the order receiving device 70 via the communication unit 66 (step ST13). In the order device 60, the processes of displaying the order screen 100, acquiring the order information entered on the order screen 100, and transmitting the order information to the order receiving device 70 are performed by the control unit 61 of the order device 60 executing a predetermined program that is pre-installed in the storage unit 65.

[0020] When order information is transmitted from the order placement device 60, the order processing unit 72 of the order receiving device 70 receives the order information from the order placement device 60 via the communication unit 76 (step ST21). The design unit 73 of the order receiving device 70 designs the eyeglass lens 10 based on the received order information (step ST22). The design method for the eyeglass lens 10 will be described in detail later. The order receiving device 70 outputs the design data for the eyeglass lens 10 designed by the design unit 73 to the processing machine control device 80 via the communication unit 76.

[0021] The processing machine control device 80 sends processing instructions to the spectacle lens processing machine 85 based on the design data output from the order receiving device 70 (step ST23). As a result, the spectacle lens processing machine 85 processes and manufactures the spectacle lenses based on the design data. The spectacle lenses 10 (i.e., a pair of spectacle lenses 1) manufactured by the spectacle lens processing machine 85 are shipped to the optician, fitted into spectacle frames, and provided to the customer (wearer W). In the order receiving device 70, the processing of receiving order information from the order receiving device 60, the processing of designing spectacle lenses based on the received order information, and the processing of outputting the spectacle lens design data to the processing machine control device 80 are performed by the control unit 71 of the order receiving device 70 by executing a predetermined program that has been pre-installed in the storage unit 75.

[0022] Next, the method for evaluating sensitivity will be described. In this embodiment, the wearer's sensitivity to blur is evaluated by having the wearer view multiple blurred images C and / or the original image C0 (see Figure 6) with each of their eyes. The image before blurring is referred to as the original image C0. Figure 6 is a diagram illustrating the original image C0 and the blurred image C. Figure 6(A) shows the original image C0 consisting of the letter "E". Figure 6(B) shows multiple blurred images Cα, Cβ, and Cγ generated by applying different degrees of blurring to the original image C0 in Figure 6(A). Blurred image Cα has slight distortion of the outline, and the degree of blurring is small. Blurred image Cβ has a moderate degree of blurring, to the point that the outline lines are not clearly recognizable. Blurred image Cγ is generally unclear, and the degree of blurring is large.

[0023] The blurred image C is a virtual representation of the perceived image of the original image C0 as it would appear when viewed through spectacle lenses with aberrations (such as astigmatism or refractive error). The degree of aberration in the spectacle lenses corresponds to the degree of blur in the generated blurred image C. In the example shown in Figure 6, the degree of astigmatism in the spectacle lenses corresponds to the degree of blur in blurred image C. Therefore, based on information regarding the wearer's sensitivity to blurred images C with different degrees of blur, the optical characteristics of the spectacle lenses 10, such as astigmatism, can be appropriately set to suit the wearer W.

[0024] To generate a blurred image C, for example, a model is used in which the original image C0 is placed at a predetermined distance from the front of the eyeball (the distance between the wearer and the blurred image when evaluating sensitivity), and the spectacle lens is placed in the optical path from the original image C0 to the retina of the eyeball. Ray tracing is performed from a certain point in the original image C0 to obtain the point spread function (PSF) on the retina. Then, the blurred image C is generated by convolutional integration of the brightness and color intensity of each point in the original image C0 using the point spread function. Note that the ray tracing calculation can be performed using, for example, a PC (Personal Computer). In the ray tracing model, it is possible to generate multiple blurred images C with different amounts of blur by appropriately changing the aberrations of the spectacle lens (astigmatism, refractive power errors, etc.).

[0025] For example, by setting the minimum aberration to 0[D] (i.e., the aberration of the spectacle lens corresponding to the original image C0), the maximum aberration to 1[D] to 3[D], and the aberration pitch interval to 0.05[D] to 0.25[D], multiple blurred images C are generated. This allows the aberration of the corresponding spectacle lens to be determined by linking multiple blurred images C with different amounts of blur.

[0026] When multiple blurred images C or original images C0 are displayed, a display device 96 (see Figure 7) provided in the evaluation device 95 is used to display different images to each of the wearer's eyes. As schematically shown in Figure 7, the evaluation device 95 includes a display device 96, a display control unit 97, a storage unit 98, and an input unit 99. The display device 96 is configured to allow each of the wearer's eyes to simultaneously view different images, for example, using a head-mounted display or a polarized display (also called a 3D display) that utilizes a polarizing filter. The display control unit 97 controls the display device 96 to select and display one of the multiple blurred images C and original images C0. The storage unit 98 stores pre-generated image data of multiple blurred images C and original images C0 in a readable format. The input unit 99 is configured using, for example, a mouse or keyboard. For example, information regarding the multiple blurred images C or original images C0 to be displayed on the display device 96 is input via the input unit 99.

[0027] The evaluation device 95 may be incorporated into the ordering device 60, or it may be installed separately at the eyeglass store (on the ordering side). The evaluation device 95 may also have an image generation unit (not shown) that generates a plurality of blurred images C. In this embodiment, the plurality of blurred images C may be referred to as blurred images C1 to Cn (where n is an integer of 2 or more). For example, when n=5, blurred images C1 to C5 represent blurred image C1 with the smallest amount of blur, blurred image C2 with the second smallest amount of blur, blurred image C3 with the third smallest amount of blur, blurred image C4 with the fourth smallest amount of blur, and blurred image C5 with the largest amount of blur. Similarly, blurred images C1 to Cn represent blurred image C1 with the smallest amount of blur, ... and blurred image Cn with the largest amount of blur.

[0028] Figure 8 is a flowchart showing the procedure for evaluating the wearer's sensitivity, corresponding to step ST11. When evaluating the wearer's sensitivity, the customer adjusts the wearer's visual acuity using corrective lenses, etc., so that the wearer can clearly see the original image C0 (step ST111). At this time, the customer may adjust the wearer's visual acuity while the wearer is wearing the display device 96. By configuring the display device 96 using a head-mounted display or a polarizing display (3D display), etc., the wearer's visual acuity can be adjusted so that the original image C0 can be clearly seen at a position corresponding to a predetermined distance (the distance between the wearer and the blurred image when evaluating sensitivity) from the front of the eyeball via the eyepiece optical system provided in the display device 96.

[0029] Next, the ordering party has the wearer wear the display device 96 and has the wearer view either the original image C0 or the blurred images C1 to Cn with each of their eyes, and determines the acceptable value of astigmatism Pb that is acceptable for binocular viewing (i.e., does not cause discomfort to the wearer) (step ST112). Specifically, as shown in Figure 9, the wearer is made to view the original image C0, the blurred image C1 with the smallest amount of blur, the blurred image C2 with the second smallest amount of blur, the blurred image C3 with the third smallest amount of blur, the blurred image C4 with the fourth smallest amount of blur, and so on, with each of their eyes. At this time, the wearer viewing the blurred images is asked to respond verbally or by inputting into the input unit 99 of the evaluation device 95 whether or not it is acceptable for binocular viewing. Then, among the blurred images that are acceptable to view with both eyes (for example, blurred images C1 to C3 in Figure 9), the aberration amount corresponding to the blurred image with the largest amount of blur (for example, blurred image C3 in Figure 9) is determined as the tolerance value Pb for astigmatism. Hereafter, this tolerance value Pb for astigmatism may be referred to as the base tolerance value Pb. Note that the order in which the original image C0 or blurred images C1 to Cn are viewed is not limited to the order in which the amount of blur increases from the original image C0, but may also be in the order in which the amount of blur decreases from the blurred image Cn with the largest amount of blur, or it may be in a random order.

[0030] The client determines the base tolerance Pb, and then sets the reference blur image Cp as the reference blur image, which corresponds to an aberration amount of 1 / 3 to 2 / 3 of the base tolerance Pb among the blur images C1 to Cn. The client has the wearer view the reference blur image Cp with one of their eyes (e.g., the right eye), and has the wearer view a blur image with a blur amount greater than or equal to the reference blur image Cp with the other eye (e.g., the left eye), and determines the tolerance PR of astigmatism that is acceptable to view with both eyes (step ST113). For example, as shown in Figure 9, the other eye (e.g., the left eye) is shown the following images in order: a reference blurred image Cp, a blurred image Cp+1 with a greater amount of blur than the reference blurred image Cp, a blurred image Cp+2 with a greater amount of blur than the blurred image Cp+1, a blurred image Cp+3 with a greater amount of blur than the blurred image Cp+2, a blurred image Cp+4 with a greater amount of blur than the blurred image Cp+3, and so on. At this time, the wearer viewing the blurred images is asked to respond verbally or by inputting into the input unit 99 of the evaluation device 95 whether or not it is acceptable to view them with both eyes. Then, the amount of aberration corresponding to the blurred image with the largest amount of blur that is acceptable to view with both eyes among the blurred images Cp+1, Cp+2, ... viewed by the other eye (e.g., the left eye) is determined as the acceptable value PR for astigmatism. In addition, the difference ΔPR between the determined acceptable value PR for astigmatism and the base acceptable value Pb is calculated. Hereafter, the difference ΔPR between the tolerance value PR for astigmatism and the tolerance value Pb for the base is sometimes referred to as the first tolerance value ΔPR.

[0031] Then, the ordering party has the wearer view a reference blurred image Cp with the other eye (e.g., the left eye), and has the wearer view a blurred image with a blur amount equal to or greater than the reference blurred image Cp with the other eye (e.g., the right eye), and determines the acceptable astigmatism aberration PL that can be viewed with both eyes (step ST114). At this time, in the same manner as in step ST113, the amount of aberration corresponding to the blurred image with the largest blur amount that can be viewed with both eyes among the blurred images Cp+1, Cp+2, ... viewed with one eye (e.g., the right eye) is determined as the acceptable astigmatism aberration PL. In addition, the difference ΔPL between the determined acceptable astigmatism aberration PL and the base acceptable value Pb is calculated. Hereafter, this difference ΔPL between the acceptable astigmatism aberration PL and the base acceptable value Pb may be referred to as the second acceptable value ΔPL.

[0032] The reference blur image Cp or the blur images Cp+1, Cp+2, ... may be selected from the blur images C1 to Cn used in the previous step ST112, or they may be newly generated according to the base tolerance value Pb. When selecting from the blur images C1 to Cn used in the previous step ST112, in the example shown in Figure 9, the blur image C3 with the third smallest amount of blur is set as the reference blur image Cp. Also, the order in which the reference blur image Cp or the blur images Cp+1, Cp+2, ... are viewed is not limited to the order in which the amount of blur increases from the reference blur image Cp, but may also be in the order in which the amount of blur decreases from the blur image with the largest amount of blur, or it may be in a random order.

[0033] In this way, information regarding the first tolerance ΔPR and the second tolerance ΔPL is obtained as information regarding sensitivity to the difference in the amount of blur between the two eyes. Once each process for evaluating the wearer's sensitivity (steps ST111 to ST114) is completed, the process proceeds to inputting order information (step ST12). In the example of the order screen 100 shown in Figure 5, the strength of sensitivity to blur is represented by a numerical value on a 10-point scale based on the first tolerance ΔPR and the second tolerance ΔPL.

[0034] Next, the design method for the eyeglass lens 10 will be described. Figure 10 is a flowchart showing the design procedure for the eyeglass lens 10 corresponding to step ST22. When designing the eyeglass lens 10, the order-taking device 70 acquires prescription data for the eyeglass lens and design parameters including information on sensitivity to the difference in the amount of blur between the two eyes (for example, information on the first tolerance ΔPR and the second tolerance ΔPL mentioned above) (step ST221). At this time, the order-taking device 70 also acquires fitting parameters such as the forward tilt angle of the frame, the curvature angle, and the distance between the eye and the lens, as appropriate.

[0035] Next, the design unit 73 of the order-taking device 70 sets the target aberration of the spectacle lens based on design parameters, including information on sensitivity to the difference in the amount of blur between the two eyes, which was obtained in the previous step ST221 (step ST222). As mentioned above, in the distance vision portion of a spectacle lens, also called a progressive power lens, the degree of blur in the right eye and the left eye when viewing a distant object can be changed by changing the distribution of astigmatism between the temporal and nasal portions, that is, by changing the symmetry of the astigmatism distribution. Here, the design parameter De adjusts the amount of astigmatism in the temporal portion of the distance vision portion of the spectacle lens. The design parameter Dn adjusts the amount of astigmatism in the nasal portion of the distance vision portion of the spectacle lens. The larger the values ​​of the design parameters De and Dn, the wider the region in which astigmatism is reduced, that is, the wider the region in which the image appears sharp.

[0036] Furthermore, the design condition where De=+5 and Dn=-5 is referred to as the first lens design condition. The design condition where De=0 and Dn=0 is referred to as the second lens design condition. The design condition where De=-5 and Dn=+5 is referred to as the third lens design condition. Figure 11(A) shows the distribution of astigmatism in the spectacle lens 10 when designed under the first lens design condition. Figure 11(B) shows the distribution of astigmatism in the spectacle lens 10 when designed under the second lens design condition. Figure 11(C) shows the distribution of astigmatism in the spectacle lens 10 when designed under the third lens design condition. Figures 11(A) to (C) indicate that the darker the image appears, the greater the astigmatism in that region. As can be seen from Figures 11(A) to (C), the symmetry of the astigmatism distribution in the spectacle lens 10 can be changed by changing the design parameters De and Dn.

[0037] Figure 12 shows a comparison of the magnitude of astigmatism in the distance vision portion of eyeglass lenses under different lens design conditions. The solid line in the graph in Figure 12 represents the magnitude of astigmatism when designed under the first lens design condition. The dashed line in the graph in Figure 12 represents the magnitude of astigmatism when designed under the second lens design condition. The double dashed line in the graph in Figure 12 represents the magnitude of astigmatism when designed under the third lens design condition. As can be seen from Figure 12, under the first lens design condition, the astigmatism in the temporal portion of the distance vision portion of the eyeglass lens becomes relatively smaller, while the astigmatism in the nasal portion becomes relatively larger. On the other hand, under the third lens design condition, the astigmatism in the temporal portion of the distance vision portion of the eyeglass lens becomes relatively larger, while the astigmatism in the nasal portion becomes relatively smaller.

[0038] Figure 13 shows the magnitude of astigmatism in the distance vision portion of the spectacle lens when designed under the first lens design condition. The solid line in the graph shown in Figure 13 shows the magnitude of astigmatism in the right eye distance vision portion 11R (see Figure 1) of the right eye spectacle lens 10R when designed under the first lens design condition. The dashed line in the graph shown in Figure 13 shows the magnitude of astigmatism in the left eye distance vision portion 11L (see Figure 1) of the left eye spectacle lens 10L when designed under the first lens design condition. As can be seen from Figure 13, under the first lens design condition, the difference in astigmatism between the right eye spectacle lens 10R (right eye distance vision portion 11R) and the left eye spectacle lens 10L (left eye distance vision portion 11L) becomes large.

[0039] Figure 14 shows the magnitude of astigmatism in the distance vision portion of the spectacle lens when designed under the second lens design condition. The solid line in the graph shown in Figure 14 shows the magnitude of astigmatism in the right eye distance vision portion 11R (see Figure 1) of the right eye spectacle lens 10R when designed under the second lens design condition. The dashed line in the graph shown in Figure 14 shows the magnitude of astigmatism in the left eye distance vision portion 11L (see Figure 1) of the left eye spectacle lens 10L when designed under the second lens design condition. As can be seen from Figure 14, under the second lens design condition, the difference in astigmatism between the right eye spectacle lens 10R (right eye distance vision portion 11R) and the left eye spectacle lens 10L (left eye distance vision portion 11L) becomes smaller.

[0040] In this embodiment, the target aberration of the spectacle lens is set based on the first tolerance ΔPR and the second tolerance ΔPL described above. Specifically, when the first tolerance ΔPR and the second tolerance ΔPL are large, the difference in astigmatism between the right-eye spectacle lens 10R (right-eye distance vision portion 11R) and the left-eye spectacle lens 10L (left-eye distance vision portion 11L) is set to be large, as in the first lens design condition. On the other hand, when the first tolerance ΔPR and the second tolerance ΔPL are small, the difference in astigmatism between the right-eye spectacle lens 10R (right-eye distance vision portion 11R) and the left-eye spectacle lens 10L (left-eye distance vision portion 11L) is set to be small, as in the second lens design condition. In other words, the larger the first tolerance ΔPR and the second tolerance ΔPL, the smaller the astigmatism of the temporal portion of the right eye distance vision portion 11R of the right eye spectacle lens 10R is than the astigmatism of the nasal portion of the left eye distance vision portion 11L of the left eye spectacle lens 10L, and the smaller the astigmatism of the temporal portion of the left eye distance vision portion 11L of the left eye spectacle lens 10L is than the astigmatism of the nasal portion of the right eye distance vision portion 11R of the right eye spectacle lens 10R.

[0041] As in the first lens design condition, when the difference in astigmatism is set to be large, as shown in Figure 13, the area with small aberrations widens in the right portion, i.e., the temporal portion, of the right eye distance vision section 11R of the right eye spectacle lens 10R. Therefore, the range in which distant objects can be recognized with only the right eye, like in monovision, widens. Similarly, the area with small aberrations widens in the left portion, i.e., the temporal portion, of the left eye distance vision section 11L of the left eye spectacle lens 10L. Therefore, the range in which distant objects can be recognized with only the left eye, like in monovision, widens. However, because the amount of astigmatism differs between the temporal and nasal portions of the distance vision section of the spectacle lens, the amount of blur when viewing the right or left side of a distant object differs between the left and right eyes. Consequently, for wearers who are prone to discomfort when the first tolerance ΔPR and the second tolerance ΔPL are small, i.e., when there is a difference in how things look (amount of blur) between the two eyes, this spectacle lens design will be uncomfortable.

[0042] On the other hand, when the second lens design condition is set to minimize the difference in astigmatism, the distribution of astigmatism in the distance vision portion of the spectacle lens becomes nearly symmetrical, as shown in Figure 14. As a result, the appearance (amount of blur) when viewing the right or left side of a distant object becomes almost the same for both eyes, making it less likely to cause discomfort. However, for wearers with large tolerances for the first tolerance ΔPR and the second tolerance ΔPL, that is, those who are less likely to experience discomfort even if there is a difference in the appearance (amount of blur) between the two eyes, they may perceive the range of clearly visible objects as narrower than under the first lens design condition.

[0043] Furthermore, the design parameters De and Dn can be calculated according to the first tolerance ΔPR and the second tolerance ΔPL. First, to simplify the calculation, we will describe the case where the same design parameters De and Dn are used for the right eye spectacle lens 10R and the left eye spectacle lens 10L. In this case, the design parameter De is expressed by the following equation (1), and the design parameter Dn is expressed by the following equation (2). De = D0 + ΔP × k ···(1) Dn = D0 - ΔP × k ... (2)

[0044] Here, ΔP is the arithmetic mean of the first tolerance ΔPR and the second tolerance ΔPL. D0 is a design parameter set, for example, when the same design parameter is used for the temporal and nasal sides with respect to astigmatism adjustment. k is a predetermined coefficient. D0 and k vary depending on the prescription data of the spectacle lens and the allowable limit of astigmatism (blur). Since wearers use the temporal side of the spectacle lens more often than the nasal side, the design parameter De for the temporal side of the spectacle lens is set to be larger than the design parameter Dn for the nasal side.

[0045] Next, we will describe the case where different design parameters are used for the right eye spectacle lens 10R and the left eye spectacle lens 10L. In this case, the design parameter DRe, which adjusts the amount of astigmatism in the temporal portion of the right eye distance vision portion 11R of the right eye spectacle lens 10R, is expressed by the following equation (3), and the design parameter DRn, which adjusts the amount of astigmatism in the nasal portion, is expressed by the following equation (4). DRe = D0 + ΔPR × k ... (3) DRn = D0 - ΔPL × k ... (4)

[0046] Furthermore, the design parameter DLe, which adjusts the amount of astigmatism in the temporal portion of the left eye distance vision portion 11L of the left eye spectacle lens 10L, is expressed by the following equation (5), and the design parameter DLn, which adjusts the amount of astigmatism in the nasal portion, is expressed by the following equation (6). DLe = D0 + ΔPL × k ... (5) DLn = D0 - ΔPR × k ... (6)

[0047] Here, D0 and k are the same as those described in equations (1) and (2) above.

[0048] Once the target aberration for the spectacle lens is set, the order-taking device 70 determines the overall shape of the spectacle lens (step ST223). After determining the overall shape of the spectacle lens, the order-taking device 70 determines whether the optical properties of the spectacle lens, such as refractive power and astigmatism, satisfy the desired conditions (step ST224). If the optical properties do not satisfy the desired conditions, i.e., the determination in step ST224 is NO, the process returns to step ST223. If the desired conditions are satisfied, i.e., the determination in step ST224 is YES, the spectacle lens design process is terminated. Once each process for designing the spectacle lens (steps ST221 to ST224) is completed, the process proceeds to the processing of the spectacle lens (step ST23).

[0049] In this embodiment, the wearer's right and left eyes are shown images with different amounts of blur (e.g., original image C0 or blurred images C1-Cn), and information regarding the wearer's sensitivity to the difference in blur between the images shown to the right and left eyes is acquired. This allows for the evaluation of the wearer's sensitivity to the difference in how the images appear (amount of blur) to both eyes, and enables the design of appropriate spectacle lenses based on the acquired information regarding the wearer's sensitivity. For example, one of the wearer's eyes is shown a reference blurred image (first image) Cp with a predetermined amount of blur (amount of blur corresponding to the reference blurred image Cp), and the other eye is shown blurred images (second images) Cp+1, Cp+2,... having a greater amount of blur than the reference blurred image Cp. Then, information regarding the wearer's sensitivity to the difference in blur between the blurred images Cp+1, Cp+2,... shown to the other eye and the reference blurred image Cp shown to the first eye is acquired. Specifically, among the blurred images Cp+1, Cp+2, ... viewed by the other eye, the aberration amount corresponding to the blurred image with the maximum amount of blur acceptable for viewing with both eyes is determined as the tolerance value PR for astigmatism, and the difference ΔPR (first tolerance ΔPR) between the tolerance value PR for astigmatism and the base tolerance value Pb (i.e., the aberration amount corresponding to the reference blurred image Cp) is calculated.

[0050] Furthermore, the wearer is shown a reference blurred image Cp with the other eye, and blurred images Cp+1, Cp+2, ... with the other eye. Then, information is obtained regarding the wearer's sensitivity to the difference in blur amount between the blurred images Cp+1, Cp+2, ... seen with one eye and the reference blurred image Cp seen with the other eye. Specifically, the aberration amount corresponding to the blurred image with the maximum amount of blur acceptable for both eyes among the blurred images Cp+1, Cp+2, ... seen with one eye is determined as the tolerance value PL for astigmatism, and the difference ΔPL (second tolerance ΔPL) between the tolerance value PL for astigmatism and the base tolerance value Pb is determined. This allows for accurate evaluation of the wearer's sensitivity to the difference in how things appear (amount of blur) with both eyes, and based on the obtained information regarding the wearer's sensitivity (i.e., information regarding the first tolerance ΔPR and the second tolerance ΔPL), an appropriate spectacle lens can be designed.

[0051] Furthermore, in this embodiment, blurred images (third images) C1 to Cn are made to be viewed by both the first and second eyes with the same amount of blur, and information regarding the wearer's sensitivity to the amount of blur of the blurred images C1 to Cn is obtained. Specifically, the amount of aberration corresponding to the blurred image with the maximum amount of blur among the blurred images that are acceptable to be viewed with both eyes is determined as the tolerance value Pb for astigmatism (base tolerance value Pb). Then, a reference blurred image Cp (i.e., a predetermined amount of blur corresponding to the reference blurred image Cp) is set based on the base tolerance value Pb. This makes it possible to accurately evaluate the wearer's sensitivity to the difference in how things appear (amount of blur) in both eyes, and to design appropriate spectacle lenses.

[0052] Furthermore, in this embodiment, the larger the maximum value of the difference in the amount of blur that is acceptable for viewing with both eyes, i.e., the larger the first tolerance ΔPR and the second tolerance ΔPL, the smaller the aberration in the temporal portion of the right eye distance vision portion 11R of the right eye spectacle lens 10R is than the aberration in the nasal portion of the left eye distance vision portion 11L of the left eye spectacle lens 10L, and the smaller the aberration in the temporal portion of the left eye distance vision portion 11L of the left eye spectacle lens 10L is than the aberration in the nasal portion of the right eye distance vision portion 11R of the right eye spectacle lens 10R. This allows the spectacle lens 10 to be appropriately designed and manufactured to match the wearer's sensitivity to the difference in how things appear (amount of blur) with both eyes.

[0053] Furthermore, as mentioned above, the right eye spectacle lens 10R has a right eye near-vision section 12R having refractive power suitable for near vision, and a right eye progressive section 13R provided between the right eye far-vision section 11R and the right eye near-vision section 12R, where the refractive power changes between the refractive power of the right eye far-vision section 11R and the refractive power of the right eye near-vision section 12R. The left eye spectacle lens 10L has a left eye near-vision section 12L having refractive power suitable for near vision, and a left eye progressive section 13L provided between the left eye far-vision section 11L and the left eye near-vision section 12L, where the refractive power changes between the refractive power of the left eye far-vision section 11L and the refractive power of the left eye near-vision section 12L. Thus, it is preferable that the spectacle lens 10 is a progressive refractive power lens.

[0054] In the embodiment described above, step ST112 involves having the wearer view either the original image C0 or the blurred images C1-Cn with each eye, and determining the acceptable astigmatism Pb (base acceptable value Pb) for binocular viewing. However, the embodiment is not limited to this. For example, as shown in Figure 15, step ST112 may be omitted by setting the original image C0 to the reference blurred image Cp. This allows for a simple evaluation of the wearer's sensitivity to the difference in how the images appear (amount of blur) with both eyes.

[0055] In this case, in step ST113, the ordering party has the wearer view the original image C0 with one of their eyes (e.g., the right eye), and view either the original image C0 or the blurred images C1 to Cn with the other eye (e.g., the left eye), and determines the acceptable value PR of astigmatism that is permissible for viewing with both eyes. For example, as shown in Figure 15, the other eye (e.g., the left eye) is to view the original image C0, the blurred image C1 with the smallest amount of blur, the blurred image C2 with the second smallest amount of blur, the blurred image C3 with the third smallest amount of blur, the blurred image C4 with the fourth smallest amount of blur, and so on, in that order. At this time, the wearer viewing the blurred images is asked to respond verbally or by inputting into the input unit 99 of the evaluation device 95 whether or not it is permissible for viewing with both eyes. Then, among the blurred images C1 to Cn viewed by the other eye (for example, the left eye), the aberration amount corresponding to the blurred image with the maximum amount of blur acceptable for viewing with both eyes is determined as the tolerance value PR0 for astigmatism. In addition, the difference ΔPR (first tolerance ΔPR) between the determined tolerance value PR0 for astigmatism and the aberration amount corresponding to the original image C0 is calculated. Since the aberration amount corresponding to the original image C0 is zero, the first tolerance ΔPR is equal to the tolerance value PR0 for astigmatism.

[0056] In this case, in step ST114, the ordering party has the wearer view the original image C0 with the other eye (e.g., the left eye) and view either the original image C0 or the blurred images C1-Cn with one of the wearer's eyes (e.g., the right eye), and determines the acceptable astigmatism value PL0 for viewing with both eyes. At this time, in the same manner as in step ST113, the amount of aberration corresponding to the blurred image C1-Cn that has the largest amount of blur that is acceptable for viewing with both eyes, among the blurred images C1-Cn viewed with one eye (e.g., the right eye), is determined as the acceptable astigmatism value PL0. The difference ΔPL (second tolerance ΔPL) between the determined acceptable astigmatism value PL0 and the amount of aberration corresponding to the original image C0 is also determined. Since the amount of aberration corresponding to the original image C0 is zero, the second tolerance ΔPL is also equal to the acceptable astigmatism value PL0. Furthermore, the order in which the original image C0 or the blurred images C1 to Cn are viewed is not limited to the order in which the blur amount increases from the original image C0, but may also be in the order in which the blur amount decreases from the blurred image Cn with the largest blur amount, or it may be in a random order.

[0057] In the embodiments described above, the wearer's eyes are shown the original image C0 or blurred images C1-Cn, or the reference blurred image Cp or blurred images Cp+1, Cp+2,... but the invention is not limited to this. For example, by introducing aberrations to an actual lens such as a phoropter, an image in which a predetermined image (e.g., the original image C0, etc.) is blurred (e.g., an image corresponding to blurred images C1-Cn, or the reference blurred image Cp or blurred images Cp+1, Cp+2,...) may be shown to the wearer's eyes.

[0058] In the embodiments described above, one eye is shown as the right eye and the other as the left eye; however, the embodiments are not limited to this, and one eye may be shown as the left eye and the other as the right eye. [Explanation of Symbols]

[0059] 1 pair of eyeglass lenses 10R Right eye eyeglass lens, 10L Left eye eyeglass lens

Claims

1. To make the right and left eyes perceive images with different amounts of blur, This includes obtaining information regarding sensitivity to the difference in the amount of blurring of the images viewed by the right eye and the left eye, respectively. A method for evaluating sensitivity, wherein the information regarding sensitivity to the difference in the amount of blur is information regarding the maximum value of the difference in the amount of blur that is acceptable to see with both the right and left eyes, based on responses from the subject.

2. The first image is made to be viewed by one of the right and left eyes with a predetermined amount of blur, and the second image is made to be viewed by the other of the right and left eyes with a greater amount of blur than the predetermined amount. To obtain information regarding sensitivity to the difference in the amount of blur between the second image viewed by the other eye and the first image viewed by the one eye, The other eye is made to view the first image with a predetermined amount of blur, and the first eye is made to view the second image with an amount of blur greater than the predetermined amount of blur. A method for evaluating sensitivity according to claim 1, comprising obtaining information regarding sensitivity to the difference in the amount of blur between the second image viewed by one eye and the first image viewed by the other eye.

3. The right eye and the left eye are each made to view a third image with the same amount of blur, and information is obtained regarding the sensitivity of the right eye and the left eye to the amount of blur of the third image they are each made to view. The method for evaluating sensitivity according to claim 2, further comprising setting a predetermined amount of blur based on information relating to the sensitivity of the third image to the amount of blur.

4. The method for evaluating sensitivity according to claim 3, wherein the information relating to the sensitivity to the amount of blur of the third image is information relating to the maximum amount of blur of the third image that is acceptable to be seen by both the right eye and the left eye.

5. The method for evaluating sensitivity according to claim 2, which includes setting the predetermined amount of blur to zero.

6. A method for manufacturing a pair of spectacle lenses, consisting of a right-eye spectacle lens used in the right eye and a left-eye spectacle lens used in the left eye, To make the right and left eyes perceive images with different amounts of blur, To obtain information regarding sensitivity to the difference in the amount of blur of the images viewed by the right eye and the left eye, respectively, Based on information regarding sensitivity to the difference in the amount of blur, the design of the right eye spectacle lens and the left eye spectacle lens is carried out. This includes manufacturing the right eye spectacle lens and the left eye spectacle lens based on the design described above. A method for manufacturing a pair of spectacle lenses, wherein the information relating to the sensitivity to the difference in the amount of blur is information relating to the maximum value of the difference in the amount of blur that is acceptable to see with both the right eye and the left eye, based on responses from the subject.

7. The first image is made to be viewed by one of the right and left eyes with a predetermined amount of blur, and the second image is made to be viewed by the other of the right and left eyes with a greater amount of blur than the predetermined amount. To obtain information regarding sensitivity to the difference in the amount of blur between the second image viewed by the other eye and the first image viewed by the one eye, The other eye is made to view the first image with a predetermined amount of blur, and the first eye is made to view the second image with an amount of blur greater than the predetermined amount of blur. This includes obtaining information regarding sensitivity to the difference in the amount of blur between the second image viewed by one eye and the first image viewed by the other eye, A method for manufacturing a pair of spectacle lenses according to claim 6, wherein the right eye spectacle lens and the left eye spectacle lens are designed based on information relating to sensitivity to the difference in the amount of blur between the second image viewed by the other eye and the first image viewed by the one eye, and information relating to sensitivity to the difference in the amount of blur between the second image viewed by the one eye and the first image viewed by the other eye.

8. The method for manufacturing a pair of spectacle lenses according to claim 6 or 7, wherein the right-eye spectacle lens and the left-eye spectacle lens are designed such that the greater the maximum value of the difference in the amount of blur that is acceptable to be seen by both eyes, the smaller the aberration in the temporal portion of the right-eye spectacle lens is than the aberration in the nasal portion of the left-eye spectacle lens, and the smaller the aberration in the temporal portion of the left-eye spectacle lens is than the aberration in the nasal portion of the right-eye spectacle lens.

9. The aforementioned right-eye spectacle lens has a right-eye distance vision portion having refractive power suitable for distance vision, The aforementioned left-eye spectacle lens has a left-eye distance vision portion having refractive power suitable for distance vision, A method for manufacturing a pair of spectacle lenses according to claim 8, wherein the greater the maximum value of the difference in the amount of blur that is acceptable to be seen by both eyes, the smaller the aberration in the temporal portion of the right eye distance vision portion is compared to the aberration in the nasal portion of the left eye distance vision portion, and the smaller the aberration in the temporal portion of the left eye distance vision portion is compared to the aberration in the nasal portion of the right eye distance vision portion.

10. The aforementioned right-eye spectacle lens has a near-vision portion for the right eye having refractive power suitable for near vision, and a progressive portion for the right eye provided between the far-vision portion for the right eye and the near-vision portion for the right eye, wherein the refractive power changes between the refractive power of the far-vision portion for the right eye and the refractive power of the near-vision portion for the right eye. The method for manufacturing a pair of spectacle lenses according to claim 9, wherein the spectacle lens for the left eye has a left eye near-vision portion having refractive power suitable for near vision, and a left eye progressive portion provided between the left eye far-vision portion and the left eye near-vision portion, wherein the refractive power changes between the refractive power of the left eye far-vision portion and the refractive power of the left eye near-vision portion.

Images