Spectacle lens determination method and spectacle lens determination assistance system

Abstract

A method for specifying a spectacle lens, the method comprising: a step for preparing a plurality of blurred images in which the amount of additional aberration is changed with respect to a predetermined source image; simultaneously displaying a plurality of blurred images to the testee so as to compare the appearance of the testee to obtain the subjective response of the testee, thereby measuring the sensitivity of the testee to aberration; and determining the glasses lens suitable for the testee based on the sensitivity of the testee to the aberration.

Description

Technical Field

[0001] The invention relates to a method for determining a spectacle lens and a system for assisting in determining a spectacle lens. Background Art

[0002] Various methods for designing eyeglass lenses that match the characteristics of individual wearers have been proposed. For example, Patent Document 1 describes a method for designing eyeglass lenses, which includes: displaying a plurality of blurred images produced by blurring a source image to different degrees, so that the wearer can visually recognize them; obtaining information related to the wearer's sensitivity to blur; and designing the eyeglass lenses based on the information related to the wearer's sensitivity to blur.

[0003] Furthermore, for example, Patent Document 2 describes a method for designing eyeglass lenses, comprising: displaying an image on a display device while maintaining a positional relationship between a face of a subject and the display device; obtaining information evaluating sensitivity related to the subject's vision based on an impression of the subject who has seen the image; and designing eyeglass lenses based on the information evaluating the sensitivity.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2018 / 101015

[0007] Patent Document 2: International Publication No. 2019 / 009034 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] An object of one embodiment of the present invention is to provide a technique for determining eyeglass lenses suitable for a subject by taking into account the subject's sensitivity to aberrations.

[0010] Technical solutions for solving technical problems

[0011] The first scheme of the present invention is a method for determining eyeglass lenses, comprising the following steps: preparing a plurality of blurred images in which the amount of added aberration is varied relative to a specified source image; simultaneously showing the plurality of blurred images to a subject to compare the appearance, obtaining the subject's subjective response, and thereby measuring the subject's sensitivity to aberrations; and determining eyeglass lenses suitable for the subject based on the subject's sensitivity to aberrations.

[0012] The second scheme of the present invention is based on the method for determining the eyeglass lens described in the first scheme. In the process of preparing the multiple blurred images, a plurality of similar blurred images similar to the multiple blurred images are also prepared. In the process of measuring the sensitivity of the subject to aberrations, the multiple similar blurred images are simultaneously displayed to the subject so that the subject compares their appearances, and the subjective responses of the subject are obtained multiple times, thereby measuring the stability of the subjective responses.

[0013] A third aspect of the present invention is based on the method for determining eyeglass lenses described in the first aspect, wherein in the step of preparing the plurality of blurred images, a plurality of blurred images with varying degrees of difficulty are further prepared, wherein the plurality of blurred images with varying degrees of difficulty are easier to understand or more difficult to understand the difference in appearance than the plurality of blurred images.

[0014] In the process of measuring the subject's sensitivity to aberrations, the multiple blurred images with varying difficulty levels are simultaneously shown to the subject to make comparisons of appearances, and the subject's subjective responses are obtained multiple times, thereby measuring the subject's sensitivity to aberrations.

[0015] A fourth aspect of the present invention is based on the method for determining the eyeglass lens described in the first aspect, and in the step of preparing the plurality of blurred images, the source image is selected based on a characteristic direction in which the spatial frequency characteristic is reduced due to the additional aberration.

[0016] A fifth aspect of the present invention is the method for determining a spectacle lens according to the first aspect, wherein in the step of determining the spectacle lens, a progressive diopter lens is determined.

[0017] The sixth scheme of the present invention is based on the method for determining the eyeglass lenses described in the first scheme above, and in the process of measuring the subject's sensitivity to aberrations, the multiple blurred images are displayed at a size where the spatial frequency of the main parts of the multiple blurred images is greater than 3CPD and less than 9CPD.

[0018] The seventh scheme of the present invention is based on the method for determining the eyeglass lenses described in the first scheme above. In the process of measuring the subject's sensitivity to aberrations, the subject's head is not fixed, and the multiple blurred images are displayed at a distance of more than 0.3m and less than 2m from the subject's eyes.

[0019] The eighth scheme of the present invention is a system for assisting in determining eyeglass lenses, comprising: a storage unit that stores a plurality of blurred images in which the amount of added aberration is varied relative to a specified source image; a display unit that simultaneously displays the plurality of blurred images to a subject so that the subject can compare their appearance; an input unit that inputs the subject's subjective response; a judgment unit that judges the subject's sensitivity to aberrations based on the subjective response; and an output unit that outputs information for determining eyeglass lenses suitable for the subject based on the sensitivity to the aberrations.

[0020] Effects of the Invention

[0021] According to one embodiment of the present invention, it is possible to determine eyeglass lenses suitable for a subject in consideration of the subject's sensitivity to aberrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flowchart showing an example of the method for identifying the spectacle lens according to the first embodiment of the present invention.

[0023] Figure 2 It is a diagram showing an example of a source image and a plurality of blurred images according to the first embodiment of the present invention.

[0024] Figure 3 This is a diagram showing an example of a spot image formed by aberration added to a blurred image according to the first embodiment of the present invention.

[0025] Figure 4 This is a diagram showing an example of a quasi-blurred image according to the first embodiment of the present invention.

[0026] Figure 5 This is a diagram for explaining the characteristic direction of the spatial frequency characteristics of the source image according to the first embodiment of the present invention.

[0027] Fig. 6A This is an image in which a downward aberration is added to an image of text that is read on the right side of the paper (source image).

[0028] Figure 6B This is an image in which an upward aberration is added to an image of a text that is read on the right side of a paper (source image).

[0029] Figure 6C This is an image in which aberration in the right direction is added to an image of text that is read on the right side of the paper (source image).

[0030] Fig.6D This is an image in which aberration in the left direction is added to an image of text that is read on the right side of the paper (source image).

[0031] Fig. 7A This is an image in which a downward aberration is added to an image of text that is read at the bottom of the paper (source image).

[0032] Figure 7B This is an image in which an upward aberration is added to an image of text that is read at the bottom of the paper (source image).

[0033] Figure 7C This is an image in which aberration in the right direction is added to the image of the text that is read at the bottom of the paper (source image).

[0034] Fig.7D This is an image in which aberration in the left direction is added to the image of the text that is read at the bottom of the paper (source image).

[0035] Fig. 8A It is a graph showing the power distribution and astigmatism distribution of the spectacle lens according to the example of the present invention.

[0036] Figure 8B It is a graph showing the power distribution and astigmatism distribution of the spectacle lens according to the example of the present invention. DETAILED DESCRIPTION

[0037] <Insights Obtained by the Inventor>

[0038] First, the findings obtained by the inventors are described. As described in Patent Document 1, it is known that when a plurality of blurred images are sequentially displayed, the evaluation may be different depending on the subject's memory, fatigue, adaptation, etc., and the sensitivity to blur (hereinafter also referred to as sensitivity to aberration) may not be accurately measured. In addition, there is also the problem of a long measurement time.

[0039] The inventors of the present invention have conducted in-depth research on the above-mentioned problems. As a result, it was found that by showing a plurality of blurred images to a subject at the same time and allowing the subject to compare the appearance, the sensitivity to blur can be accurately measured without being affected by the subject's memory, fatigue, adaptability, etc. Moreover, the measurement time can be shortened. In addition, since a plurality of blurred images are compared, a relative evaluation can be performed, which has the advantage that the subject can easily evaluate. Therefore, considering the subject's sensitivity to blur, it is easy to determine the eyeglass lenses suitable for the subject.

[0040] [Details of Embodiments of the Invention]

[0041] Next, an embodiment of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0042] <First embodiment of the present invention>

[0043] (1) Method for determining eyeglass lenses

[0044] First, a method for determining the spectacle lens according to the present embodiment will be described. Figure 1 FIG. 4 is a flowchart showing an example of a method for determining a spectacle lens according to the present embodiment. Figure 1 As shown, the spectacle lens determination method of this embodiment includes, for example, a blur image preparation step S101, a blur sensitivity measurement step S102, and a spectacle lens determination step S103. In this embodiment, a case of determining a progressive diopter lens suitable for a subject will be described.

[0045] (Blurred image preparation step S101)

[0046] The blurred image preparation step S101 is, for example, a step of preparing a plurality of blurred images (two blurred images in this embodiment) in which the amount of added aberration is varied (preferably only by that amount) relative to a predetermined source image. It should be noted that in this embodiment, the added aberration includes astigmatism, coma, trefoil, etc. Figure 2 An example of a source image and multiple blurred images. Figure 2 , a blurred image 10A in which a predetermined amount of aberration is added to the source image 10 and a blurred image 10B in which the amount of aberration added is larger than that of the blurred image 10A are shown.

[0047] Figure 3 This is an example of a light spot image formed by the aberration added to the blurred image. Figure 3 In the figure, a light spot image with a tail is shown at the lower left of the paper. Such a blurred image with the added aberration forming the light spot image appears blurred in the lower left direction. In other words, due to the added aberration, the spatial frequency characteristics of the lower left are significantly (characteristically) reduced. In this specification, such a characteristic direction in which the spatial frequency characteristics are reduced due to the added aberration is referred to as the direction of the aberration.

[0048] In the blurred image preparation step S101, the directions of the aberrations added to the multiple blurred images (for example, blurred image 10A and blurred image 10B) are preferably roughly consistent. As a result, it is easy for the subject to compare the appearance of the multiple blurred images. It should be noted that in this specification, the directions of the aberrations are roughly consistent, which means that in addition to the situation where the directions are completely consistent, it also includes the situation where there is a slight difference of less than ±15 degrees in the direction of the aberrations. In addition, the direction of the aberration refers to the direction of the component with the largest absolute value among all the coefficients of all the blurred images when the aberrations added to the blurred images displayed simultaneously are expanded by Zernike polynomials.

[0049] It should be noted that, in the blurred image preparation step S101 , when selecting the aberration to be added to the source image, it is possible to arbitrarily select from among the aberrations generated by a standard progressive-power lens, for example.

[0050] (Fuzzy sensitivity measurement step S102)

[0051] The blur sensitivity measurement step S102 is, for example, a step of showing a plurality of blur images to a subject at the same time to make the subject compare their appearances, thereby obtaining the subject's subjective response and measuring the subject's sensitivity to aberration. Figure 2 The blurred image 10A and the blurred image 10B shown are compared in appearance to select which one is clear. Then, when the blurred image 10A with a small amount of additional aberration is selected (hereinafter, also referred to as the case where the correct answer is selected), it can be judged that the sensitivity to blur is high, and when the blurred image 10B with a large amount of additional aberration is selected (hereinafter, also referred to as the case where an incorrect answer is selected), it can be judged that the sensitivity to blur is low. It should be noted that in this specification, displaying multiple blurred images at the same time means displaying multiple blurred images in a manner that allows visual recognition in a state where multiple blurred images exist in the subject's field of view, and the timing of starting or ending the display of each blurred image is not limited (for example, the timing of starting or ending the display of the blurred image 10A and the blurred image 10B can be staggered).

[0052] However, when judging the sensitivity to blur by a single subjective response, for example, even if the difference in appearance is not actually seen, there may be a case where a blurred image with a small amount of aberration is occasionally selected. Therefore, in the blurred image preparation step S101 of the present embodiment, it is preferable to prepare a plurality of similar blurred images similar to the plurality of blurred images, and in the blur sensitivity measurement step S102, the plurality of similar blurred images, that is, a plurality of similar blurred images in which the amount of added aberration (preferably only the amount) is varied, are simultaneously shown to the subject, so that the subject compares the appearance, and the subjective response of the subject is obtained multiple times, thereby measuring the stability of the subjective response. The similar blurred images are described in detail below.

[0053] Figure 4 An example of a similar blurred image similar to the blurred image 10A and the blurred image 10B is shown. In this specification, a similar blurred image refers to, for example, an image obtained by rotating a blurred image by an arbitrary angle, or an image obtained by enlarging or reducing a blurred image by an arbitrary magnification. Figure 4In the figure, similar blurred images 20A and 20B are obtained by rotating blurred images 10A and 10B by 90 degrees, similar blurred images 21A and 21B are obtained by rotating blurred images 10A and 10B by 180 degrees, and similar blurred images 22A and 22B are obtained by rotating blurred images 10A and 10B by 270 degrees. In this case, for example, in the blur sensitivity measurement step S102, two (similar) blurred images (e.g., similar blurred image 20A and similar blurred image 20B) with the same rotation angle are simultaneously displayed, and the subjects are asked to compare their appearances and select which one is clearer four times, thereby obtaining four subjective responses from the subjects. Then, for example, when an image with a small amount of added aberration (blurred image 10A, similar blurred images 20A, 21A, 22B) is selected every time, it is determined that the stability of the subjective response is high, and when an image with a small amount of added aberration and an image with a large amount of added aberration are selected about half and half, it is determined that the stability of the subjective response is low. The high stability of the subjective response proves that the sensitivity to the added aberration is high, and by measuring the stability of the subjective response, the sensitivity to blur can be measured more accurately. As a result, it is easy to determine the eyeglass lenses suitable for the subject.

[0054] It is important that blurred images and similar blurred images are not identical images, although the source images are common. When the same blurred image is used to obtain subjective responses multiple times, the influence of the subject's fitness is strong, and there is a possibility that the sensitivity to blur cannot be accurately measured. In contrast, by using similar blurred images, the influence of the subject's fitness can be reduced, and the sensitivity to blur can be measured more accurately. In addition, in the blur sensitivity measurement step S102, in order to further reduce the influence of the subject's fitness, the display positions of the attached image with a small amount of aberration and the attached image with a large amount of aberration can be swapped for display.

[0055] In order to measure the subject's sensitivity to blur in more detail, in the blurred image preparation step S101 of the present embodiment, it is preferred to further prepare a plurality of blurred images of varying difficulty whose differences in appearance are easier or more difficult to understand than the plurality of blurred images, and in the blur sensitivity measurement step S102, the plurality of blurred images of varying difficulty are simultaneously shown to the subject to compare their appearances, and the subjective responses of the subject are obtained multiple times, thereby measuring the subject's sensitivity to aberration. The following describes the details of the blurred images of varying difficulty.

[0056] When a plurality of blurred images are simultaneously displayed with the amount of added aberrations varied relative to a predetermined source image, there are blurred images whose appearance difference is easy to understand and blurred images whose appearance difference is difficult to understand. In this specification, the ease of understanding (difficulty of understanding) of the difference in appearance of such blurred images is expressed as difficulty. The difficulty of a blurred image is affected by the amount and direction of the added aberrations and the spatial frequency characteristics of the source image. Therefore, for example, if the difference in the amount of aberrations added to two blurred images is large, the difficulty does not necessarily decrease. In order to determine the difficulty of a blurred image, for example, VSOTF can be calculated for each of the plurality of blurred images, and the difficulty can be determined based on the difference in VSOTF. Alternatively, the appearance can be compared by a plurality of subjects, and the difficulty can be determined based on the correct answer rate. VSOTF is described in the following document "Thibos LN, Hong X, Bradley A, Applegate RA. Accuracy and precision of objective refraction from wavefront aberrations. J Vis. 2004 Apr 23; 4 (4): 329-51.", and the description is omitted here.

[0057] By using a plurality of blurred images with different difficulty levels, it is possible to check the degree to which the subject can distinguish the difference in appearance, and thereby to measure the subject's sensitivity to blur in stages. This makes it easy to determine the eyeglass lenses that are suitable for the subject. It should be noted that, in order to reduce the influence of the subject's adaptability, the source images of the plurality of blurred images with different difficulty levels are preferably different. Furthermore, from the perspective of smoothly performing the measurement, in the blur sensitivity measurement step S102, the initially displayed (difficulty level) blurred image is preferably of low difficulty. In addition, with respect to the plurality of blurred images with different difficulty levels, it is also preferred to prepare similar blurred images as described above, obtain the subject's subjective response multiple times, and thereby measure the stability of the subjective response.

[0058] Figure 5 This is a diagram illustrating the characteristic direction of the spatial frequency characteristics of the source image. Figure 5The source image 11 shown has a large change in contrast in the left-right direction of the paper, so it can be said that the characteristic direction of the spatial frequency characteristic is the left-right direction. For such a source image 11, for example, when aberration in the up-down direction is added, it is expected that it will become a blurred image whose appearance does not change much compared with the source image 11. That is, when the direction of the added aberration is different from the characteristic direction of the spatial frequency characteristic of the source image, it is easy to become a blurred image with high difficulty. On the other hand, for example, when aberration in the left-right direction is added to the source image 11, it is expected that it will become a blurred image whose appearance is greatly different from the source image 11. That is, when the direction of the added aberration is consistent with the characteristic direction of the spatial frequency characteristic of the source image, it is easy to become a blurred image with low difficulty. Therefore, in the blurred image preparation step S101 of the present embodiment, it is preferable to select the source image according to the characteristic direction (direction of the aberration) in which the spatial frequency characteristic is reduced due to the added aberration. Thereby, the difficulty of the blurred image can be appropriately controlled. Specifically, for example, by selecting a source image in such a way that the direction of the added aberration is roughly consistent with the characteristic direction of the spatial frequency characteristics of the source image, it is possible to avoid a blurred image that is extremely difficult for anyone to see the difference in appearance. It should be noted that in the present specification, the direction of the added aberration is roughly consistent with the characteristic direction of the spatial frequency characteristics of the source image, for example, it can mean that the absolute value of the inner product of the unit direction vectors of the two is greater than 0.7. In addition, the direction of the aberration (0°~180°) refers to the direction in which the blur becomes larger, which is obtained from the direction in which the variance of the point image intensity distribution is the largest. When using a source image without linear symmetry, a symbol can be further added based on the direction from the peak point of the point image distribution function to the center of gravity (that is, the direction of the aberration is set to -180°~180°).

[0059] In the blur sensitivity measurement step S102, for example, it is preferred to display multiple blurred images at a size such that the spatial frequency of the main part of the multiple blurred images is greater than 3CPD and less than 9CPD (equivalent to visual acuity 0.1 to 0.3). For example, when a blurred image of a size that can only be seen with glasses is displayed to a myopic subject, the sensitivity to blur may not be accurately measured due to the influence of the adjustment error of the glasses. In contrast, by displaying the blurred image larger than the size that most subjects can see even without glasses, individual differences in cognition can be reflected to a greater extent, so the sensitivity of the subject to blur can be measured more accurately. It should be noted that in this specification, the main part of the blurred image refers to a characteristic part in the blurred image that is easy to understand the difference in appearance. In addition, it is preferred to display multiple blurred images in the same size, but for example, even if the magnification of the multiple blurred images is slightly different (for example, a magnification of less than 5%), as long as the subject can distinguish the difference in appearance. Furthermore, the size at which the spatial frequency of the main part of the blurred image is greater than 3 CPD and less than 9 CPD (equivalent to visual acuity 0.1 to 0.3) means that, for example, when the source image is an image composed of lines or text, the width of the main lines constituting it is 1 / 6 degree to 1 / 18 degree of the viewing angle.

[0060] In the blur sensitivity measurement step S102, for example, it is preferred that the subject's head is not fixed, and a plurality of blurred images are displayed at a distance of more than 0.3 m and less than 2 m from the subject's eyes. When the subject's head is fixed for measurement, tension is caused and the subject's burden is increased. In addition, the tension of the head muscles is linked to the tension of the eye muscles, making it difficult to obtain the subject's daily eye usage pattern, and there is a possibility that the sensitivity to blur cannot be accurately measured. In contrast, by performing the measurement without fixing the subject's head, the burden on the subject can be reduced. In addition, by displaying a plurality of blurred images at a distance at which the effects of slight position changes of the head (for example, about 3 cm) can be ignored, the sensitivity to blur can be measured more accurately.

[0061] In the answer options of the subjective response in the blur sensitivity measurement step S102, in addition to which image can be clearly seen, an option such as "I don't know the difference" can also be set. The subjects who answer "I don't know the difference" more often have a subjective tendency to be less sensitive to blur. In addition, when there are many subjects who choose the correct answer at the same rate, the subjects who answer "I don't know the difference" more often are less sensitive to the aberration of the glasses than the subjects who answer "I don't know the difference" less often. In this way, by considering the answer rate of "I don't know the difference", it is easier to determine the glasses lens suitable for the subject in the glasses lens determination step S103.

[0062] It should be noted that the sensitivity to blur (or aberration) can be divided into, for example, the sensitivity to the blur size and the intensity of the bias caused by the blur direction. The sensitivity to blur described here is mainly the sensitivity to the blur size, but in the blur sensitivity measurement step S102, it is preferred to measure not only the sensitivity to the blur size but also the intensity of the bias caused by the blur direction. Figure 3 The direction in which the light spot is trailed like that shown corresponds to the direction within the range of -180° to 180°. That is, for example, the left and right directions are divided into the right direction and the left direction.

[0063] Figure 6A to Figure 6D and FIG. 7A to FIG. 7D This is a diagram showing an example of a blurred image for explaining the bias due to the blur direction. Fig. 6A This is an image with downward aberration added to the image of the text read on the right side of the paper (source image). Figure 6B This is an image with an upward aberration added to the image of the text read on the right side of the paper (the source image). Figure 6C This is an image with aberration in the right direction added to the image of the text read on the right side of the paper (source image). Fig.6D This is an image with a leftward aberration added to the image of the text read on the right side of the paper (the source image). Fig. 7A This is an image with downward aberration added to the image of the text read at the bottom of the paper (source image). Figure 7B This is an image with an upward aberration added to the image of the text read at the bottom of the paper (source image). Figure 7C This is an image with aberration in the right direction added to the image of the text read at the bottom of the paper (source image). Fig.7D This is an image in which aberration in the left direction is added to the image of the text to be read at the bottom of the paper (source image).

[0064] exist Figure 6A to Figure 6D Select the one that clearly shows the aberration added to the right direction. Figure 6C ,exist FIG. 7A to FIG. 7D In the image above, select the image that clearly shows the aberration in the downward direction. Fig. 7A That is, in a blurred image containing text, when the direction of reading the text is consistent with the direction of the added aberration, there is a tendency that the blur is difficult to feel. Since the intensity of such bias varies from person to person, it is preferable to measure the degree of bias caused by the blur direction of the subject. In addition, it is preferable to make the measurement taking into account the differences caused by the language that the subject usually uses.

[0065] As described above, the sensitivity to the size of blur can be measured, for example, by showing a plurality of blurred images with different amounts of added aberration to the subject and determining whether the difference can be recognized. Here, from the viewpoint of reducing the influence of the bias caused by the direction of blur and more accurately determining the sensitivity to the size of blur, it is preferred to show the subject blurred images in which the direction of the added aberration is changed by 180° and obtain multiple subjective responses. Furthermore, the degree of bias caused by the direction of blur can be estimated, for example, based on the degree of consistency or inconsistency of the answers when the direction of the added aberration is changed by 180°.

[0066] In addition, from the viewpoint of reducing the influence of the bias caused by the blur direction and more accurately measuring the sensitivity to the blur size, for example, it is preferable to show the subject a blurred image in which the inner product of the direction of the added aberration and the unit direction vector of the characteristic direction of the spatial frequency characteristics of the source image is 0.7 or more and a blurred image in which the inner product is -0.7 or less, so as to obtain multiple subjective responses. Specifically, for example, for a source image of a text to be read from the right, it is preferable to prepare approximately the same number of blurred images in which aberration in the right direction is added and blurred images in which aberration in the left direction is added and show them to the subject.

[0067] (Spectacle Lens Determination Step S103)

[0068] The spectacle lens determination step S103 is a step of determining a spectacle lens suitable for the subject based on the subject's sensitivity to aberration measured in the blur degree measurement step S102, for example. In the spectacle lens determination step S103, it is preferable to determine a progressive diopter lens. This is because the influence of aberration is large in a progressive diopter lens, and therefore it is particularly important to consider the subject's sensitivity to blur.

[0069] Specifically, for example, in the blur sensitivity measurement step S102, for a subject who has stably selected the correct answer, it can be determined that the subject has a high sensitivity to blur, and a progressive diopter lens that does not leave aberrations on the main meridian as much as possible can be determined. Also, for example, for a subject who has stably selected an incorrect answer, it can be determined that the subject has a high sensitivity to blur but prefers a state with large aberrations, and a progressive diopter lens with aberrations that the subject prefers can be determined. Also, for example, for a subject who is unstable in selecting the correct answer or incorrect answer and answers that he / she does not know the difference a few times, it can be determined that the subject has a low sensitivity to blur but does not subjectively recognize that the sensitivity is low, and a progressive diopter lens with a balanced design of a low aberration design and a design that improves other aspects (for example, a design that emphasizes power) can be determined. Also, for example, for a subject who answers that he / she does not know the difference a lot of times, it can be determined that the subject has a low sensitivity to blur, and a progressive diopter lens with a design that improves other aspects instead of retaining aberrations on the main meridian can be determined.

[0070] A downward aberration is generated near the main meridian of a progressive diopter lens with a positive addition power. Therefore, in the spectacle lens determination step S103, the bias caused by the direction of blur can be taken into consideration, and the progressive diopter lens is determined as follows. For example, for a subject who is highly sensitive to the size of blur and has a small bias caused by the direction of blur, it can be determined that the blur on the main meridian is easy to feel (or has a high sensitivity to blur), and a progressive diopter lens is determined that does not leave aberrations on the main meridian as much as possible. And, for example, for a subject who is highly sensitive to the size of blur and has a large bias caused by the direction of blur, it can be determined that it is difficult to feel blur on the main meridian (feel peripheral blur), and a progressive diopter lens designed to improve peripheral aberrations instead of leaving aberrations on the main meridian is determined. Furthermore, for example, for a subject who is less sensitive to the size of blur and has a small bias due to the direction of blur, it can be determined that blur on the main meridian is difficult to feel (or has a low sensitivity to blur), and a progressive diopter lens designed to improve peripheral aberrations instead of residual aberrations on the main meridian is determined. Furthermore, for example, for a subject who is less sensitive to the size of blur and has a large bias due to the direction of blur, it can be determined that blur is hardly felt, and a progressive diopter lens designed to improve other aspects (depth of focus, etc.) instead of residual aberrations on the main meridian is determined.

[0071] In the spectacle lens determination step S103, the spectacle lens may be determined in consideration of the residual refractive error of the subject. Specifically, for example, for a subject with strong refractive error such as astigmatism, the spectacle lens may be determined by assuming that the spectacle lens actually has a slightly higher sensitivity than the sensitivity measured in the blur sensitivity measurement step S102, taking into account the possibility that the difference in appearance of a blurred image is difficult to understand.

[0072] (2) Spectacle lens identification assistance system

[0073] The present invention can also be applied as a spectacle lens determination assistance system. The spectacle lens determination assistance system of this embodiment, for example, has: a storage unit that stores a plurality of blurred images in which the amount of added aberration is changed relative to a specified source image; a display unit that simultaneously displays a plurality of blurred images to a subject so that the subject can compare the appearance; an input unit that inputs the subject's subjective response; a determination unit that determines the subject's sensitivity to aberration based on the subject's subjective response; and an output unit that outputs information for determining a spectacle lens suitable for the subject based on the subject's sensitivity to aberration. The spectacle lens determination assistance system of this embodiment can be implemented, for example, by a tablet terminal equipped with a specified program, and has the advantage of low introduction cost. In addition, the spectacle lens determination assistance system of this embodiment can further have a production unit that adds a specified aberration to the source image to produce a blurred image.

[0074] <Other embodiments of the present invention>

[0075] As mentioned above, although embodiment of this invention is specifically described, this invention is not limited to the said embodiment, Various changes are possible within the range which does not deviate from the summary.

[0076] For example, in the above-mentioned embodiment, it is explained that two blurred images are prepared in which the amount of added aberration is changed relative to a specified source image, and the two blurred images are displayed at the same time to compare their appearances, but three or more blurred images may be prepared and displayed at the same time to compare their appearances. However, in the case of displaying more than three blurred images at the same time to compare their appearances, there is a possibility that the difference caused by the position in the field of view is dominant. In addition, there is a possibility that it is difficult for the subject to judge. Therefore, from the viewpoint of reducing the difference caused by the position in the field of view and displaying a blurred image that is easy for the subject to judge, it is preferred to display two blurred images at the same time to compare their appearances as in the above-mentioned embodiment.

[0077] Furthermore, for example, in the above embodiment, the directions of the aberrations added to the multiple blurred images displayed simultaneously are described as being approximately the same, but it is not necessary to make the directions of the aberrations added to the multiple blurred images displayed simultaneously approximately the same. Specifically, for example, it is also possible not to add astigmatism to one blurred image (in the direction where the aberration does not exist), and to add astigmatism to the other blurred image (in the direction where the aberration exists). In this case, as in the above embodiment, it is easy for the subject to compare the appearances of the multiple blurred images.

[0078] Example

[0079] Next, examples of the present invention will be described. These examples are examples of the present invention, and the present invention is not limited to these examples.

[0080] (Blurred image preparation step S101)

[0081] In this embodiment, two blurred images are displayed simultaneously. First, six different source images are prepared, and six blurred images with different degrees of difficulty are prepared in pairs (difficulty-varying blurred images). In addition, for the six blurred images in pairs, the rotation angle is changed, and three (four in total with the original blurred image) similar blurred images are prepared for each pair, and a total of twenty-four blurred image pairs are prepared.

[0082] (Fuzzy sensitivity measurement step S102)

[0083] In this embodiment, the tablet terminal was made to display a pair of blurred images 24 times in a random order, and the subjects were asked to compare the appearance and get subjective responses on which one they could see clearly. The blurred images were enlarged to a size where the spatial frequency of the main part was about 6 CPD (equivalent to visual acuity 0.2), and were shown to the front of the subjects at a distance of 1m.

[0084] In this embodiment, subjects who selected blurred images with a small amount of optical aberration (or blurred images with a good evaluation index) most of the time (e.g., 18 times or more out of 24 times) were set as Group A with high sensitivity to aberration, subjects who selected blurred images with a small amount of optical aberration (or blurred images with a good evaluation index) moderately (e.g., 7 times or more and 17 times or less out of 24 times) were set as Group B with low sensitivity to aberration, and subjects who rarely selected blurred images with a small amount of optical aberration (or blurred images with a good evaluation index) were set as Group C who evaluated images from a different viewpoint from the designer. It should be noted that in this specification, the evaluation index is an index indicating the visibility of a blurred image calculated based on the VSOTF of the blurred image or the selection results of past subjects.

[0085] (Spectacle Lens Determination Step S103)

[0086] In this embodiment, based on the subject's sensitivity to aberration measured in the blur sensitivity measuring step S102, a progressive diopter lens suitable for the subject is determined. Specifically, for example, for group A, a lens having Fig. 8A The progressive power lenses with the power distribution (power) and astigmatism distribution (AS) shown in Figure 2 were used to determine the Figure 8B The progressive diopter lens with power distribution (power) and astigmatism distribution (AS) shown. Fig. 8A As shown in Figure 2, subjects who are highly sensitive to aberrations are suitable for lenses that do not have astigmatism on or near the principal meridian, such as Figure 8B As shown, it can be said that the subjects with low sensitivity to aberration are suitable for the following lenses: although there is astigmatism on the main meridian, the range of sufficient near addition is large in the left and right direction. It should be noted that in the measurements previously conducted by the inventors of the present invention, there were no subjects belonging to Group C. However, since objective optical indicators are difficult to apply to Group C, additional investigations based on consultations, etc. can be conducted to determine the spectacle lenses.

[0087] As described above, it was confirmed that spectacle lenses suitable for the subject can be determined in consideration of the subject's sensitivity to aberrations.

[0088] Description of Reference Numerals

[0089] 10, 11: source images;

[0090] 10A, 10B: blurred images;

[0091] 20A, 20B, 21A, 21B, 22A, 22B: similar blurred images;

[0092] S101: Blurred image preparation process;

[0093] S102: Fuzzy sensitivity measurement process;

[0094] S103: Eyeglass lens determination step.

Claims

1. A method for determining a spectacle lens, characterized in that: The process includes: preparing a plurality of blurred images in which the amount of added aberration is varied with respect to a predetermined source image; Simultaneously showing the multiple blurred images to a subject to compare their appearances, obtaining a subjective response from the subject, and thereby measuring the subject's sensitivity to aberrations; Based on the subject's sensitivity to aberrations, a pair of eyeglass lenses suitable for the subject is determined.

2. The method for determining a spectacle lens according to claim 1, In the step of preparing the plurality of blurred images, a plurality of similar blurred images similar to the plurality of blurred images are further prepared. In the process of measuring the subject's sensitivity to aberration, the multiple similar blurred images are simultaneously shown to the subject to make the subject compare their appearances, and the subject's subjective response is obtained multiple times to measure the stability of the subjective response.

3. The method for determining a spectacle lens according to claim 1, In the step of preparing the plurality of blurred images, a plurality of blurred images with varying difficulty levels are further prepared, wherein the plurality of blurred images with varying difficulty levels are easier to understand or more difficult to understand the difference in appearance than the plurality of blurred images. In the process of measuring the subject's sensitivity to aberrations, the multiple blurred images with varying difficulty levels are simultaneously shown to the subject to make comparisons of appearances, and the subject's subjective responses are obtained multiple times, thereby measuring the subject's sensitivity to aberrations.

4. The method for determining a spectacle lens according to claim 1, In the step of preparing the plurality of blurred images, the source image is selected based on a characteristic direction in which a spatial frequency characteristic is reduced due to the additional aberration.

5. The method for determining a spectacle lens according to claim 1, In the step of determining the spectacle lens, a progressive-power lens is determined.

6. The method for determining a spectacle lens according to claim 1, In the step of measuring the subject's sensitivity to aberration, the plurality of blurred images are displayed at a size such that a spatial frequency of a main portion of the plurality of blurred images is greater than or equal to 3 CPD and less than or equal to 9 CPD.

7. The method for determining a spectacle lens according to claim 1, In the step of measuring the subject's sensitivity to aberration, the head of the subject is not fixed, and the plurality of blurred images are presented at a distance of not less than 0.3 m and not more than 2 m from the subject's eyes.

8. A system for assisting the determination of eyeglass lenses, characterized in that: have: a storage unit that stores a plurality of blurred images in which the amount of added aberration is varied with respect to a predetermined source image; a display unit for simultaneously displaying the plurality of blurred images to the subject so that the subject can compare their appearances; An input unit for inputting a subjective response of the subject; a determination unit configured to determine the subject's sensitivity to aberrations based on the subjective response; An output unit outputs information for determining eyeglass lenses suitable for the subject based on the sensitivity to the aberration.

Images