Ophthalmologic examination apparatus and ophthalmologic examination method

Abstract

To provide an ophthalmologic examination apparatus and an ophthalmologic examination method capable of evaluating whether a subject eye can easily adapt to stereoscopic vision in which a mismatch between convergence and adjustment occurs.SOLUTION: An ophthalmologic examination apparatus 100 includes a target projection system 4, objective measurement optical systems 6, 7, and a control unit 140. A display 41 presents a left-eye projection target 8L and a right-eye projection target 8R having the same asterisk 82 (pattern) at target positions separated from the left and right subject eyes EL, ER by a predetermined examination distance Lid. The target projection system 4 prescribes a condition in which the convergence distance L from the positions of the left and right subject eyes EL, ER to a convergence position R where two lines of sight intersect is changed by changing the prism angles from the left and right subject eyes EL, ER toward the left-eye projection target 8L and the right-eye projection target 8R. When fusion is attempted with the left and right subject eyes EL, ER for the change in the convergence distance L, the control unit 140 measures the ocular characteristics of the left and right subject eyes EL, ER using the objective measurement optical systems and acquires objective refractive values as objective measurement information.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an ophthalmic examination apparatus and an ophthalmic examination method. [Background technology]

[0002] As ophthalmic examination techniques, for example, the techniques described in Patent Documents 1 to 5 have been proposed. Patent Document 1 describes a technique for providing ophthalmic examination information for more appropriately prescribing corrective lenses for subjects with heterophoria. Patent Document 2 describes a technique for providing an ophthalmic measurement device that can measure the subject's eye in a state where the subject's eye is close to natural vision and appropriately fused. Patent Document 3 describes a technique for providing an ophthalmic examination system that can easily confirm the position of the gaze of the subject's eye and perform an appropriate eye examination. Patent Document 4 describes a technique for providing an ophthalmic device that can appropriately perform an objective examination of the state related to eye position. Patent Document 5 describes a technique for providing an ophthalmic device that can appropriately perform an objective examination of the state related to eye position. Patent Document 6 describes a technique for easily confirming the fusion state when performing an examination with both eyes open and performing accurate measurement. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-038942 [Patent Document 2] Patent Publication No. 2021-019957 [Patent Document 3] JP 2020-069201 A [Patent Document 4] JP 2019-069049 A [Patent Document 5] JP 2019-063238 A [Patent Document 6] JP 2018-047050 A Summary of the Invention [Problem to be solved by the invention]

[0004] By the way, when watching normal 3D images, there is a mismatch between convergence, which is the eye movement when fusing two images with both eyes, and accommodation, which is the accommodative function when focusing on an image with both eyes. In other words, between convergence and accommodation, when fusing two visual targets with both eyes, there is a range of convergence where accommodation can be constant (relative convergence) and a range of accommodation where convergence can be constant (relative accommodation). For this reason, it is known that when the range of relative convergence or relative accommodation is exceeded, a convergence movement that cooperates with the accommodation response (accommodative convergence) or an accommodation action induced by convergence (vergence accommodation) occurs. Here, "vergence" refers to the eye movement in which the eyes move in different directions when the line of sight is moved to an object at a different distance (depth) from the observer, in which the eyes move in the direction in which the eyes come together.

[0005] In contrast, the prior art, none of Patent Documents 1 to 5, describes a configuration in which two targets are placed at a certain distance from the subject's eyes, and when the two targets are fused with both eyes, a convergence stimulus is applied to reproduce a state in which a mismatch occurs between convergence and accommodation. For this reason, the prior art cannot evaluate whether the left and right eyes to be examined are easily adapted to stereoscopic vision in which a mismatch occurs between convergence and accommodation.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an ophthalmic examination apparatus and an ophthalmic examination method that can evaluate whether the left and right eyes to be examined are likely to adapt to stereoscopic vision, in which a mismatch between convergence and accommodation occurs. [Means for solving the problem]

[0007] The ophthalmic examination device of the present invention includes a target projection system having a target presentation unit that presents fixation targets to the left and right eyes to be examined, an objective measurement optical system that objectively measures the eye characteristics of the left and right eyes to be examined, and a control unit that controls each unit of the device. The fixation targets are left-eye projected targets and right-eye projected targets having the same design and are projected onto the left and right eyes to be examined, respectively. The target presentation unit presents the left-eye projected targets and the right-eye projected targets at target positions that are a certain test distance away from the left and right eyes to be examined. The target projection system prescribes a state in which the convergence distance from the positions of the left and right eyes to the convergence position where the two lines of sight intersect changes by changing the line-of-sight angle from the left and right eyes to the left-eye projected targets and the right-eye projected targets. When fusion is attempted using the left and right test eyes in response to a change in the convergence distance, the control unit measures the ocular characteristics of the left and right test eyes using the objective measurement optical system and obtains objective refraction values ​​as objective measurement information.

[0008] The ophthalmic examination method of the present invention includes a complete correction prescription step, a target presentation step, a vergence distance control step, an accommodation response amount measurement step, and a judgment step. The complete correction prescription step sets the left and right test eyes in a state where a complete correction value in a subjective test is prescribed. The target presentation step, following the prescription of the complete correction value, presents a left eye projection target and a right eye projection target having the same design on the target presentation unit at a target position a certain test distance away from the left and right test eyes. The convergence distance control step prescribes a state in which the convergence distance from the position of the left and right test eyes to a convergence position where two lines of sight intersect changes by controlling the change in the line of sight angle from the left and right test eyes toward the left eye projection target and the right eye projection target. The accommodation reaction amount measuring step is executed in parallel with the control of the convergence distance, and when the left and right test eyes attempt to fuse with respect to a change in the convergence distance, the eye characteristics of the left and right test eyes are measured by the objective measurement optical system, and objective refraction values ​​are obtained as objective measurement information. The judgment step judges the adaptability of the left and right test eyes to stereoscopic vision based on the objective refraction values. Effect of the Invention

[0009] The ophthalmic examination apparatus and the ophthalmic examination method according to the present invention can evaluate whether the left and right eyes to be examined are likely to adapt to stereoscopic vision in which a mismatch between convergence and accommodation occurs. [Brief description of the drawings]

[0010] [Figure 1] 1 is an external perspective view of an ophthalmic examination apparatus according to a first embodiment. [Diagram 2] 2 shows a schematic configuration example of a left measurement optical system in the ophthalmic examination apparatus of the first embodiment. [Diagram 3] 2 shows a control block configuration in the ophthalmic examination apparatus of the first embodiment. [Figure 4] 1 shows a flowchart illustrating a processing procedure of an ophthalmic examination method according to a first embodiment. [Figure 5A] 1 shows an example of a left eye projection target. [Figure 5B] 1 shows an example of a right eye projection target. [Figure 6] An explanatory diagram of the convergence distance up to the convergence point where two lines of sight intersect is shown below. [Figure 7A] An example is shown in which the convergence distance to the convergence position coincides with the inspection distance. [Figure 7B] An example in which the convergence distance to the convergence position is closer than the test distance is shown. [Figure 7C] An example in which the convergence distance to the convergence position is farther than the test distance is shown. [Figure 8A] 1 shows a prism angle time chart for measuring convergence and accommodation. [Figure 8B] Examples of measurement results of convergence and refraction (accommodation) in a normal eye are shown. [Figure 8C] Example 1 of the measurement results of convergence and refraction (accommodation) in the fatigue group is shown. [Figure 8D] Example 2 of the measurement results of convergence and refraction (accommodation) in the fatigue group is shown. [Figure 8E] 4 shows examples of analysis results of the refraction time change frequency for a healthy group and a fatigue group. [Figure 9] A plurality of test eyes show relationship characteristics between the prism angle and the objective refraction value to be measured. [Figure 10]13 is a flowchart showing the processing steps of an ophthalmic examination method according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ophthalmic examination apparatus and an ophthalmic examination method according to the present invention will be described below with reference to a first embodiment and a second embodiment shown in the drawings.

[0012] The ophthalmic examination apparatus applied to the first and second embodiments is an apparatus of a binocular open type that can measure the ocular characteristics of both eyes simultaneously while the examinee keeps both the right and left eyes open. This ophthalmic examination apparatus can also measure the ocular characteristics of one eye at a time by blocking one eye or turning off the fixation target. In addition, the ophthalmic examination apparatus is an objective measurement device with a subjective test function that has a target presentation function, a phoropter function, and an autoreflex-keratometer measurement function. In other words, the examiner can use the ophthalmic examination apparatus to perform any objective test and subjective test and objectively and subjectively measure the ocular characteristics of the examinee's eye.

[0013] Objective examinations that can be performed by an ophthalmic examination apparatus include measurements for acquiring eye characteristics of the subject's eye and photography for acquiring an image of the subject's eye. Objective examinations include refractive power measurement (refractometry), corneal shape measurement (keratometry), intraocular pressure measurement, fundus photography, tomography (OCT photography) using optical coherence tomography (hereinafter referred to as "Optical Coherence Tomography"), and measurements using OCT. In subjective examinations, visual targets are presented to the subject, and information about the subject's eye (eye characteristics) is measured based on the subject's response to the presented visual targets. Subjective examinations include subjective refraction measurements such as distance examination, intermediate distance examination, near examination, contrast examination, and glare examination, as well as visual field examination. EXAMPLES

[0014] [Overall configuration of the device (Fig. 1)] The overall configuration of the ophthalmic examination apparatus 100 will be described below with reference to Fig. 1. As shown in Fig. 1, the ophthalmic examination apparatus 100 includes a support base 110, a measurement unit 120, an examiner's controller 130, and a control unit 140. As for the axes used in the drawings and description, when viewed from the examinee, the left-right axis (horizontal axis) is the X-axis, the up-down axis (vertical axis) is the Y-axis, and the depth axis (front-rear axis) perpendicular to the X-axis and Y-axis is the Z-axis.

[0015] The support base 110 has a support column 111 standing up from the floor surface, and an optometry table 112 supported by the support column 111. The optometry table 112 is a platform on which devices and tools used in optometry, such as the examiner controller 130, are placed, and which supports the posture of an examinee. The optometry table 112 may have a fixed position in the Y-axis direction (height position), or may be supported by the support column 111 so that the position in the Y-axis direction (height position) is adjustable.

[0016] The measurement unit 120 has an arm 121, a measurement head 122, and a forehead rest 123. One end of the arm 121 is supported by the tip of the support 111, and the other end extends from the support 111 to the front side (subject side) along the Z direction, with the measurement head 122 attached to the tip. As a result, the measurement head 122 is suspended from the support 111 via the arm 121 above the optometry table 112. The arm 121 is movable in the Y-axis direction relative to the support 111. The arm 121 may also be movable in the X-axis direction or the Z-axis direction relative to the support 111.

[0017] The measurement head 122 measures the ocular characteristics of the subject's eye. The measurement head 122 has a drive unit 122a, a pair of left and right measurement head units 122L and 122R provided below the drive unit 122a, and a forehead rest unit 123. Here, the left measurement head unit 122L and the right measurement head unit 122R correspond to the left and right eyes of the subject, respectively.

[0018] The drive unit 122a is a mechanism that individually drives the left measurement head unit 122L and the right measurement head unit 122R to move in the horizontal direction (X-axis direction), move in the vertical direction (Y-axis direction), rotate around the X-axis, and rotate around the Y-axis.

[0019] The left measurement head unit 122L incorporates a left measurement optical system 125L. The left measurement optical system 125L presents a visual target to the subject's left eye (hereinafter, "left eye") and measures the eye characteristics of the left eye with the spherical power (correction power) set to an arbitrary value. The right measurement head unit 122R incorporates a right measurement optical system 125R. The right measurement optical system 125R presents a visual target to the subject's right eye (hereinafter, "right eye") and measures the eye characteristics of the right eye with the spherical power (correction power) set to an arbitrary value. The measurement results by the left measurement optical system 125L and the right measurement optical system 125R are hereinafter referred to as objective measurement information. The detailed configurations of the left measurement optical system 125L and the right measurement optical system 125R will be described in "Configuration of optical system" below.

[0020] The forehead rest 123 is provided in the measurement unit 120 and is disposed between the left measurement head 122L and the right measurement head 122R. The forehead rest 123 supports the subject's face by contacting a part of the face (forehead) with the forehead rest 123 during measurement of eye characteristics. That is, the subject facing the optometry table 112 presses his / her forehead against the forehead rest 123 to stabilize the direction and position of the face. The position of the forehead rest 123 in the height direction is adjusted by moving the arm 121 in the Y-axis direction relative to the support 111.

[0021] The examiner's controller 130 is an information processing device that accepts an input operation by the examiner and outputs a control signal to the control unit 140. The examiner's controller 130 is, for example, a tablet terminal or a smartphone, and is separated from the measurement unit 120 and can be carried by the examiner. The examiner's controller 130 may be a notebook personal computer or a desktop personal computer, or may be a dedicated controller provided in the ophthalmic examination apparatus 100. The examiner's controller 130 exchanges information with the control unit 140 via wireless communication or network communication.

[0022] As shown in Fig. 1, the examiner's controller 130 includes a display unit 131 and an operation-side control unit (not shown). The display unit 131 is made up of a touch panel display provided on the surface of the examiner's controller 130, and input buttons 132 (see Fig. 3) and the like are set by screen display. The operation-side control unit is made up of a microcomputer built into the examiner's controller 130. The operation-side control unit controls images to be displayed on the display unit 131 based on measurement results and detection results transmitted from the control unit 140. The operation-side control unit also outputs control signals to the control unit 140 in response to operations on the displayed input buttons 132 and the like.

[0023] [Optical system configuration (Fig. 2)] The detailed configurations of the left measurement optical system 125L and the right measurement optical system 125R will be described below with reference to Fig. 2. The left measurement optical system 125L and the right measurement optical system 125R have the same configuration. Therefore, in this document, illustration and description of the right measurement optical system 125R corresponding to the right test eye ER will be omitted, and only the left measurement optical system 125L corresponding to the left test eye EL will be described.

[0024] The left measurement optical system 125L is an optical system that performs an examination by presenting a visual target to the left test eye EL. As shown in FIG. 2, the left measurement optical system 125L includes a Z alignment system 1, an XY alignment system 2, a keratometry system 3, a visual target projection system 4, an anterior eye observation system 5, a reflex measurement projection system 6, and a reflex measurement light receiving system 7. In the following description, the "fundus conjugate position P" is a position that is optically approximately conjugate with the fundus ELf of the left test eye EL when alignment is completed, and means a position optically conjugate with the fundus ELf of the left test eye EL or its vicinity. The "pupil conjugate position Q" is a position that is optically approximately conjugate with the pupil of the left test eye EL when alignment is completed, and means a position optically conjugate with the pupil of the left test eye EL or its vicinity.

[0025] The Z alignment system 1 projects light (infrared light) for alignment in the optical axis direction (front-back direction = Z axis direction) of the anterior eye observation system 5 onto the left test eye EL. The light output from the Z alignment light source 11 is collimated by the projection lens 12 and projected onto the cornea of ​​the left test eye EL through an alignment hole formed in the keratoplasty plate 31. Based on the bright spot projected onto the cornea, the control unit 140 or the examiner controls the drive unit 122a to move the left measurement optical system 125L in the Z axis direction so that the ratio between the distance between the two point images on the imaging element 59 by the Z alignment light source 11 and the diameter of the keratoplasty image falls within a predetermined range.

[0026] The XY alignment system 2 irradiates the left test eye EL with light (infrared light) for alignment in the X-axis direction and the Y-axis direction perpendicular to the optical axis (Z-axis) of the anterior eye observation system 5. The XY alignment system 2 includes an XY alignment light source 21 and a projection lens 22, which are provided on an optical path branched from the anterior eye observation system 5 by a half mirror 54. The light output from the XY alignment light source 21 passes through the projection lens 22, is reflected by the half mirror 54, and is projected onto the left test eye EL through the anterior eye observation system 5. The light reflected by the cornea of ​​the left test eye EL is guided to the image sensor 59 through the anterior eye observation system 5. The alignment method in each of the XYZ directions is not limited to the method using the Z alignment system 1 and the XY alignment system 2. For example, any method can be used as long as it can measure the position of the test eye E by using a stereo camera installed in the ophthalmic apparatus 100.

[0027] Here, the image based on the light reflected by the cornea (bright spot image) is included in the anterior eye image. The control unit 140 controls the display unit 131 to display the anterior eye image including the bright spot image and the alignment mark. When performing manual XY alignment, the examiner uses the examiner controller 130 to control the drive unit 122a to guide the bright spot image into the alignment mark, and moves the left measurement optical system 125L in the X-axis direction and the Y-axis direction. When performing automatic XY alignment, the control unit 140 controls the drive unit 122a to cancel the displacement of the bright spot image relative to the alignment mark, and moves the left measurement optical system 125L in the X-axis direction and the Y-axis direction.

[0028] The keratometry system 3 projects a ring-shaped light beam (infrared light) onto the cornea of ​​the left subject eye EL to measure the shape of the cornea. The keratoplate 31 is disposed between the objective lens 52 and the left subject eye EL, and the keratoplate light source 32 is provided on the rear side (the objective lens 52 side). The keratoplate light source 32 projects a ring-shaped light beam onto the cornea of ​​the left subject eye EL by illuminating the keratoplate 31 with light from the rear. The reflected light (keratoplate image) from the cornea of ​​the left subject eye EL is detected by the imaging element 59 together with the anterior eye image. The control unit 140 calculates a corneal shape parameter that represents the shape of the cornea by performing a known calculation based on the keratoplate image.

[0029] The target projection system 4 presents various targets, such as a fixation target and a target for subjective testing, to the left eye EL. The target projection system 4 includes a display 41, a half mirror 42, a relay lens 43, a reflecting mirror 44, a focusing lens 45, a relay lens 46, a field lens 47, a variable cross cylinder lens (VCC) 48, and a reflecting mirror 49. The target projection system 4 shares a dichroic mirror 68 with the reflector measurement projection system 6. The target projection system 4 shares a dichroic mirror 53 and an objective lens 52 with the anterior eye observation system 5. Furthermore, the target projection system 4 includes at least two glare light sources 41a that irradiate the left eye EL with glare light at positions surrounding the optical axis on an optical path different from the optical path leading to the display 41 that displays the left eye projected target.

[0030] The light output from the display 41 is reflected by the half mirror 42, passes through the relay lens 43, is reflected by the reflecting mirror 44, and passes through the focusing lens 45. The light that passes through the focusing lens 45 passes through the relay lens 46, has its traveling direction aligned by the field lens 47, passes through the VCC 48, is reflected by the reflecting mirror 49, passes through the dichroic mirror 68, and is reflected by the dichroic mirror 53. The light reflected by the dichroic mirror passes through the objective lens 52 and is projected onto the fundus ELf.

[0031] The display 41 displays a fixation target or a dot target as a target to fix the gaze when performing an objective test or when fogging the left eye EL, or a subjective test target for subjectively testing the eye characteristics of the left eye EL (visual acuity, distance power, near power, etc.). The display 41 uses a liquid crystal display. Note that an organic EL display or the like can also be used as the display 41. The targets to be projected onto the left eye EL and the right eye ER can be arbitrarily created as still images or moving images, and the created targets can be registered as selectable chart icons on the chart page. The display 41 can select and display the created still image targets or moving image targets from the chart page. The display 41 is provided at a fundus conjugate position P on the optical path of the target projection system 4.

[0032] The focusing lens 45 is driven to move forward and backward in the optical axis direction by a drive motor (not shown) controlled by the control unit 140. When the control unit 140 controls the focusing lens 45 to move in a direction toward the left subject eye EL, the spherical power of the left subject eye EL is changed to the minus diopter side (-D side). When the control unit 140 controls the focusing lens 45 to move in a direction away from the left subject eye EL, the spherical power of the left subject eye EL is changed to the plus diopter side (+D side). Furthermore, the control unit 140 controls the forward and backward drive of the focusing lens 45 to change the test distance from the left subject eye EL to the optotype presentation position. Here, the focusing lens 45, the reflex measurement light source 61, and the focusing lens 74 are configured to move in conjunction with each other.

[0033] When a subjective test is performed, the control unit 140 moves the focusing lens 45 in the optical axis direction based on the result of the objective measurement, and controls the test distance and the spherical power of the left test eye EL. Then, the control unit 140 displays a predetermined optotype selected by the examiner or the control unit 140 on the display 41. As a result, the optotype is presented to the subject at a predetermined test distance for the left test eye EL adjusted to a predetermined spherical power. Also, when the subject gives a subjective response to the optotype, the control unit 140 receives an input of the response. For example, in the case of visual acuity measurement, the examiner selects and presents the next optotype based on the subject's subjective response to a Landolt ring or the like, and the control unit 140 determines the visual acuity value by repeating this process.

[0034] The anterior eye observation system 5 observes and photographs the anterior eye of the left eye EL. The anterior eye illumination light source 51 irradiates the anterior eye of the left eye EL with illumination light (e.g., infrared light). The light reflected by the anterior eye of the left eye EL passes through the objective lens 52, the dichroic mirror 53, the half mirror 54, the relay lens 55 and the relay lens 56, and the dichroic mirror 57. The light transmitted through the dichroic mirror 57 forms an image on the imaging surface of the imaging element 59 by the imaging lens 58. The imaging element 59 performs imaging and signal output at a predetermined rate. The output (video signal) of the imaging element 59 is input to the control unit 140. The control unit 140 displays an anterior eye image (moving image) based on the video signal output from the imaging element 59 on the display unit 131 of the examiner's controller 130. The imaging surface of the imaging element 59 in the optical system of the anterior eye observation system 5 is disposed at a pupil conjugate position Q.

[0035] The refraction measurement projection system 6 and the refraction measurement light receiving system 7 are objective measurement optical systems used for objective refraction measurement (refraction measurement) to measure the objective refraction value as an ocular characteristic of the left test eye EL. Hereinafter, the refraction measurement projection system 6 and the refraction measurement light receiving system 7 are referred to as the objective measurement optical systems 6, 7. The refraction measurement projection system 6 projects a ring-shaped light beam (infrared light) for objective measurement from a refraction measurement light source 61 onto the fundus ELf. The refraction measurement light receiving system 7 receives the return light of this ring-shaped light beam from the left test eye EL.

[0036] The reflex measurement light source 61 may be an SLD (Super luminescent Diode) light source, which is a high-brightness light source with a light emission diameter of a predetermined size or less. The reflex measurement light source 61 can move in the optical axis direction in conjunction with the focusing lens 45 and the focusing lens 74, and is arranged at the fundus conjugate position P. The ring diaphragm 65 (specifically, the light transmitting portion) is arranged at the pupil conjugate position Q. The focusing lens 74 can move in the optical axis direction in conjunction with the reflex measurement light source 61 and the focusing lens 45. The focusing lens 74 may be a known variable focus lens whose focal position can be changed under the control of the control unit 140. The imaging surface of the imaging element 59 in the optical system of the reflex measurement light receiving system 7 is arranged at the fundus conjugate position P.

[0037] The light output from the reflector measurement light source 61 passes through a relay lens 62 and is incident on the conical surface of a conical prism 63. The light incident on the conical surface is deflected and exits from the bottom surface of the conical prism 63. The light exiting from the bottom surface of the conical prism 63 passes through a field lens 64 and passes through a light-transmitting portion formed in a ring shape in an aperture ring 65. The light (ring-shaped light beam) that passes through the light-transmitting portion of the aperture ring 65 is reflected by the reflecting surface of an aperture prism 66, passes through a rotary prism 67, and is reflected by a dichroic mirror 68. The light reflected by the dichroic mirror 68 is reflected by a dichroic mirror 53, passes through the objective lens 52, and is projected onto the left test eye EL.

[0038] It is desirable that the conical prism 63 is disposed as close as possible to the pupil conjugate position Q. The conical prism 63 may have, for example, a ring diaphragm 65 attached to its bottom surface facing the field lens 64. In this case, for example, a light-shielding film is evaporated onto the bottom surface of the conical prism 63 so that a ring-shaped light-transmitting portion is formed. The ring diaphragm 65 may also be located on the conical surface side of the conical prism 63.

[0039] The field lens 64 may have a ring diaphragm 65 attached to the lens surface on the side of the left eye EL. In this case, for example, a light-shielding film is deposited on the lens surface of the field lens 64 so as to form a ring-shaped light-transmitting portion. The reflex measurement projection system 6 may be configured without the field lens 64. The ring diaphragm 65 may be a diaphragm formed with a light-transmitting portion having a shape corresponding to a predetermined measurement pattern, and the light-transmitting portion may be formed in this diaphragm at a position eccentric to the optical axis of the reflex measurement projection system 6. The diaphragm may have two or more light-transmitting portions. The rotary prism 67 is used to average the light amount distribution of the ring-shaped light beam for the blood vessels and diseased parts of the fundus ELf and to reduce speckle noise caused by the light source.

[0040] The return light of the ring-shaped light beam projected onto the fundus ELf passes through the objective lens 52 and is reflected by the dichroic mirror 53 and the dichroic mirror 68. The return light reflected by the dichroic mirror 68 passes through the rotary prism 67, passes through the hole of the aperture prism 66, passes through the relay lens 71, is reflected by the reflecting mirror 72, and passes through the relay lens 73 and the focusing lens 74. The light that passed through the focusing lens 74 is reflected by the reflecting mirror 75, is reflected by the dichroic mirror 57, and is imaged by the imaging lens 58 on the imaging surface of the imaging element 59.

[0041] The control unit 140 calculates the parameters of the eye refractive power by performing a known calculation based on the output from the image sensor 59. The parameters of the eye refractive power include the refraction value (refractive power), spherical power, cylindrical power, and cylindrical axis angle of the left and right test eyes EL, ER. The control unit 140 comprehensively controls each part of the measurement unit 120 including the left measurement optical system 125L and the right measurement optical system 125R having the refraction measurement projection system 6, the refraction measurement light receiving system 7, the visual target projection system 4, etc., and the drive unit 122a, based on a control signal transmitted from the examiner's controller 130. The control unit 140 also transmits the measurement results of the eye characteristics of the left test eye EL and the right test eye ER measured by the measurement head 122 to the examiner's controller 130.

[0042] [Control unit configuration (Fig. 3)] The configuration of the control unit 140 will be described below with reference to Fig. 3. The control unit 140 includes a main control unit 141, a storage unit 142, and an adaptability evaluation inspection unit 143, as shown in Fig. 3.

[0043] The main control unit 141 controls the change in light intensity and the on / off switching of the Z alignment light source 11 of the Z alignment system 1, the XY alignment light source 21 of the XY alignment system 2, and the keratometry light source 32 of the keratometry system 3. The main control unit 141 controls the on / off control of the visual target displayed on the display 41 of the visual target projection system 4, and the switching of the visual target. The main control unit 141 controls the change in light intensity and the on / off switching of the anterior eye illumination light source 51 of the anterior eye observation system 5. The main control unit 141 controls the change in exposure time and the detection sensitivity of the image sensor 59 of the anterior eye observation system 5. The main control unit 141 controls the change in light intensity and the on / off switching of the reflex measurement light source 61 of the reflex measurement projection system 6. The main control unit 141 controls the change in rotation speed of the rotary prism 67 of the reflex measurement projection system 6, and the on / off switching of the rotation operation. The main control unit 141 also controls the movement of the focusing lens 45 of the visual target projection system 4, the reflex measurement light source 61 of the reflex measurement projection system 6, and the focusing lens 74 of the reflex measurement light receiving system 7 in the optical axis direction in an interlocking manner. The main control unit 141 also controls the processing of writing data to the storage unit 142 and reading data from the storage unit 142.

[0044] The storage unit 142 stores various data. The data stored in the storage unit 142 include measurement information obtained by the keratometry system 3, measurement information obtained by the objective measurement optical systems 6 and 7, image data acquired by the image sensor 59, and information on the subject's eye. The information on the subject's eye includes information on the subject, such as a patient ID and name, and information on the left and right subject's eyes EL and ER, such as identification information of the left eye / right eye. The measurement information obtained by the keratometry system 3 is stored in the storage unit 142 when keratometry is performed on the left and right subject's eyes EL and ER. The measurement information obtained by the objective measurement optical systems 6 and 7 is stored in the storage unit 142 when refractometry is performed on the left and right subject's eyes EL and ER. The storage unit 142 may be used as a working memory for the calculation process of the corneal shape parameters and the calculation process of the refractive values ​​of the left and right subject's eyes EL and ER. In addition, the storage unit 142 stores various programs and data for operating the ophthalmic examination apparatus 100.

[0045] The adaptation evaluation test unit 143 performs a test to evaluate the adaptability of the left and right test eyes EL, ER to stereoscopic vision. The adaptation evaluation test unit 143 includes a subjective test processing unit 144, an objective measurement unit 145, and a determination unit 146.

[0046] The subjective test processing unit 144 presents the left eye projection target and the right eye projection target at a target position a certain test distance (e.g., 1 m) away from the left and right test eyes EL, ER, with the left and right test eyes EL, ER in a state where the perfect correction value in the subjective test is prescribed. The left eye projection target and the right eye projection target are set on a display 41 (target presenting unit) that presents fixation targets to the left and right test eyes EL, ER in the target projection system 4. The left eye projection target and the right eye projection target are projected onto the left and right test eyes EL, ER, respectively. The left eye projection target projected onto the left test eye EL and the right eye projection target projected onto the right test eye ER have the same pattern at the center position of the target frame.

[0047] The subjective test processing unit 144 prescribes a state in which the convergence distance from the position of the left and right test eyes EL, ER to the convergence position where the two lines of sight intersect is changed by controlling to change the line of sight angle from the left and right test eyes EL, ER toward the left eye projected target and the right eye projected target. The ophthalmic examination device 100 has a left measurement head unit 122L that incorporates a left eye projected target and a left measurement optical system 125L corresponding to the left test eye EL, and a right measurement head unit 122R that incorporates a right eye projected target and a right measurement optical system 125R corresponding to the right test eye ER (see FIG. 1). Thus, the subjective test processing unit 144 realizes the control to change the line of sight angle by controlling (rotation angle control) to change the rotation angle when the left measurement head unit 122L and the right measurement head unit 122R are rotated in opposite directions around two rotation axes (Y-axis direction) that pass through the left and right test eyes EL, ER. The rotation angle control is performed by the driving unit 122 a based on a command from the subjective test processing unit 144 .

[0048] When the left measurement head unit 122L and the right measurement head unit 122R perform the rotation angle control, the angle of the optical axis of the visual target projection system 4 from the left and right test eyes EL, ER toward the display 41 that displays the visual target is changed. In other words, the rotation angle control is equivalent to a configuration in which a prism lens is added to any position on the optical axis of the visual target projection system 4 and the deviation angle is changed by the prism lens. For this reason, the line of sight angle is hereinafter referred to as the "prism angle" which represents the prism power of the prism lens. Incidentally, when the light that has passed through the prism lens is shifted by 1 cm on a vertical screen 1 m away, the prism power of the prism lens is called 1Δ (1 prism diopter), and the deviation angle at this time is 0.57 degrees. Here, the following explanation will be made assuming that the prism power in the direction in which the convergence distance is closer to the test eye (the eye is rotated inward) is positive, and the prism power in the direction in which the convergence distance is farther from the test eye (the eye is rotated outward) is negative.

[0049] The subjective test processing unit 144 prescribes a state in which the convergence distance changes stepwise in a distance range from a position farther than the test distance to a position closer than the test distance by controlling the prism angle from the left and right test eyes EL, ER toward the left eye projection target and the right eye projection target in a stepwise manner. The subjective test processing unit 144 obtains a subjective answer from the subject when the subject attempts fusion with the left and right test eyes EL, ER in response to the stepwise change in the convergence distance.

[0050] The objective measurement unit 145 is executed in parallel with the processing in the subjective test processing unit 144. When the objective measurement unit 145 attempts fusion of the left and right test eyes EL, ER with respect to the change in the convergence distance, the objective measurement unit 145 measures the eye characteristics of the left and right test eyes EL, ER using the objective measurement optical systems 6, 7, and obtains the objective refraction value as the objective measurement information. Here, the processing in the subjective test processing unit 144 is a process of prescribing a state in which the convergence distance changes stepwise. For this reason, the objective measurement unit 145 measures the eye characteristics of the left and right test eyes EL, ER a predetermined number of times at each stage of the changing convergence distance, and obtains the objective refraction average value obtained by averaging the objective refraction values ​​obtained at each stage a predetermined number of times as the objective measurement information.

[0051] The determination unit 146 determines the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the subject's subjective response obtained by the subjective test processing unit 144 and the objective refraction value (Ref value) obtained by the objective measurement unit 145. The determination unit 146 determines that the left and right test eyes EL, ER are easily adapted to stereoscopic vision when a positive subjective response is obtained for binocular fusion regardless of the change in the convergence distance and the change range of the objective refraction value is suppressed within a predetermined range regardless of the change in the convergence distance. The determination unit 146 determines that the left and right test eyes EL, ER are not easily adapted to stereoscopic vision when a negative subjective response is obtained for binocular fusion when the convergence distance changes and the change range of the objective refraction value exceeds a predetermined range when the convergence distance changes.

[0052] [Configuration and operation flow of the process for evaluating the ability to adapt to stereoscopic vision (Figure 4)] The configuration and operation flow of the process for evaluating the adaptability to stereoscopic vision executed in the adaptability evaluation test unit 143 will be described below with reference to the flowchart shown in Fig. 4. Fig. 4 shows an example of the operation of the adaptability evaluation test unit 143.

[0053] Step S1 is a preliminary measurement step in which the main controller 141 acquires eye characteristics including the refractive values ​​of the left and right test eyes EL and ER based on the captured image of the ring image. The preliminary measurement is performed two or more times, and the same type of measurement condition may be determined by each preliminary measurement so that the measurement conditions converge each time. In each preliminary measurement, at least one of the light amount from the reflective measurement light source 61, the exposure time of the image sensor 59, the detection sensitivity of the image sensor 59, and the control content for the focusing lens 74 is determined based on the obtained ring image.

[0054] Step S2 is a main measurement step in which the main controller 141 measures the objective refraction values ​​of the left and right test eyes EL, ER under the measurement conditions determined by the last performed preliminary measurement. The measurement of the objective refraction values ​​of the left and right test eyes EL, ER is performed in the following procedure. That is, the main controller 141 projects a ring-shaped light beam (infrared light) for objective measurement onto the fundus ELf, ERf of the left and right test eyes EL, ER by the refraction measurement projection system 6. Then, the main controller 141 detects (receives) the return light of the ring-shaped light beam from the fundus ELf, ERf by the refraction measurement light receiving system 7, and obtains the objective refraction values ​​of the left and right test eyes EL, ER by a well-known method based on the image signal from the image sensor 59.

[0055] Step S3 is a subjective test start setting step in which the main controller 141 sets the subjective test start for each of the left and right test eyes EL, ER. Here, "subjective test start setting" refers to adjusting the position of the focusing lens 45 in the optotype projection system 4 so that the spherical powers of the left and right test eyes EL, ER are perfectly corrected at the test distance of far vision based on the refractive values ​​of the left and right test eyes EL, ER obtained in this measurement.

[0056] Step S4 is an RG test step in which the main controller 141 performs an RG test using an RG chart. Here, the term "RG test" refers to a test in which the RG chart is used to subjectively check whether the correction state of each of the left and right test eyes EL, ER is a perfect correction state (proper) (whether overcorrection or undercorrection is not occurring) using a characteristic of light called chromatic aberration. Also, the "RG chart" is, for example, a red icon with optotypes of numbers of different sizes and ◎ and ◯ symbols of different sizes, and a green icon with an optotype of the same shape as the red icon, arranged side by side. In the RG test, the shorter the wavelength of light is, the greater the power at the refracting surface is, due to the characteristics of the ocular optic body, so that light of green wavelength is imaged at a position shifted toward the incident side compared to light of red wavelength. Therefore, when the left and right test eyes EL, ER are in an undercorrected state, the red optotype is more clearly seen, and when the left and right test eyes EL, ER are in an overcorrected state, the green optotype is more clearly seen. Therefore, the subject repeats steps S4 and S5 until the green and red targets on the RG chart are evenly viewed, and performs an operation to adjust the spherical power (corrective power) of the left and right test eyes EL, ER by changing the position of the focusing lens 45. As a result, the left and right test eyes EL, ER are in a state where perfect correction values ​​are prescribed based on the provisionally determined values ​​in the RG test.

[0057] Steps S1 to S4 correspond to a complete correction prescription step in which the left and right test eyes EL, ER are placed in a state where the complete correction value in the subjective test is prescribed. However, the complete correction value of the left and right test eyes EL, ER does not have to be the provisionally determined value in the RG test in the first embodiment, but may be, for example, any of values ​​measured separately, prescription values ​​for the current glasses, or values ​​determined by a series of subjective eye tests. At this time, the eye position of the test eyes EL, ER may be corrected by performing a strabismus or cross-eyes test.

[0058] Step S5 is a target presentation step in which the subjective test processing unit 144 sets an initial prism angle and a test distance, and matches the convergence distance to the convergence position when the left eye projected target and the right eye projected target are fused with the test distance from the left and right test eyes EL, ER to the target position. Step S5 performs rotation angle control of the initial prism angle, for example, to match the convergence distance and the test distance (0Δ), and performs focusing lens control to set the test distance from the left and right test eyes EL, ER to a position of, for example, 1 m. This step S5 corresponds to a target presentation step in which, following the prescription of the perfect correction value, the left eye projected target and the right eye projected target having the same pattern at the center position of the target frame on the display 41 (target presentation unit) are presented at a target position a certain test distance away from the left and right test eyes EL, ER.

[0059] Step S6 is a subjective answer step in which the subjective test processing unit 144 acquires a subjective answer regarding the fusion of the left eye projected optotype and the right eye projected optotype from the subject. For example, the subjective answer is acquired as to whether the optotypes are seen as one by the fusion of the left eye projected optotype and the right eye projected optotype. Here, if the optotypes are not seen as one, it is confirmed whether the subject's eye is performing the test properly, and if not, the settings are reset to an appropriate state, and if it is, the test is stopped, or the eye position is corrected so that the optotypes are seen as one and the test may be continued.

[0060] Step S7 is a prism angle changing process step in which the subjective test processing unit 144 controls the rotation angle of the driving unit 122a to change the prism angle stepwise from 0Δ or the previous prism angle to the next prism angle while maintaining the test distance (for example, 1 m). The prism angle is changed in 11 steps, for example, 0Δ, ±1Δ, ±2Δ, ±4Δ, ±6Δ, and ±10Δ. For example, when the initial prism angle is 0Δ, it is changed in 11 steps from +1Δ → +2Δ → +4Δ → +6Δ → +10Δ → -1Δ → -2Δ → -4Δ → -6Δ → -10Δ. In this example, the test is performed in a direction approaching the subject's eye from a position where the test distance and the convergence distance match, and after changing to a predetermined distance, the test is returned to a position where the test distance and the convergence distance match, and the test is performed in a direction away from there. However, the present invention is not limited to this, and the test in the direction away from the prism angle may be performed first, and then the test in the direction approaching may be performed. Furthermore, when the approaching direction and the receding direction are switched, the subjective test processing unit 144 may perform the test again when the position is returned to where the test distance and the convergence distance match, and then continue the test.

[0061] Step S8 is a subjective answer step in which the subjective test processing unit 144 acquires a subjective answer regarding the fusion of the left eye projected target and the right eye projected target from the subject when the subject attempts fusion with the left and right eyes EL and ER in response to a gradual change in the convergence distance. For example, the subjective answer is acquired as to whether the target is seen as one object due to fusion.

[0062] Step S9 is a final prism angle determination step in which the subjective test processing unit 144 determines whether the prism angle has been changed to the final prism angle (for example, -10Δ). If the result of step S9 is NO, the process returns to step S7, and if the result of step S9 is YES, the process proceeds to step S13.

[0063] Steps S7 and S9 correspond to a convergence distance control step for prescribing a state in which the convergence distance from the positions of the left and right test eyes EL, ER to the convergence position where the two lines of sight intersect is changed by controlling the change in the prism angle from the left and right test eyes EL, ER toward the left eye projection target and the right eye projection target. Steps S6 and S8 correspond to a subjective answer acquisition step for acquiring a subjective answer regarding fusion from the test subject when fusion is attempted with the left and right test eyes EL, ER in response to the change in the convergence distance.

[0064] Step S10 is a refraction measurement step in which the objective measurement unit 145 measures the ocular characteristics of the left and right test eyes EL, ER with respect to the change in the convergence distance using the objective measurement optical system, and obtains the objective refraction value as objective measurement information. Step S11 is a refraction value display step in which the objective measurement unit 145 displays a plurality of objective refraction values ​​(refraction values) obtained at the timing when the prism angle changes. Step S12 is a refraction average calculation step in which the objective measurement unit 145 compares a plurality of refraction values ​​obtained at the timing when the prism angle changes, and calculates the average value. These steps S10 to S12 are executed in parallel with the control of the convergence distance, and correspond to an accommodation reaction amount measurement step in which, when fusion is attempted with the left and right test eyes EL, ER with respect to the change in the convergence distance, the ocular characteristics of the left and right test eyes EL, ER are measured using the objective measurement optical system, and the objective refraction value is obtained as objective measurement information.

[0065] Step S13 is a step in which the judgment unit 146 judges the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the subjective answer from the subjective test processing unit 144 and the objective refraction value (average refraction value) from the objective measurement unit 145. When the judgment of the adaptability of stereoscopic vision is completed, step S13 proceeds to the end. This step S13 corresponds to a judgment step in which the adaptability of the left and right test eyes EL, ER to stereoscopic vision is judged based on the subjective answer and the objective refraction value.

[0066] The flow of the action of each step is explained as follows. The process in Fig. 4 starts when the subject places his / her face in a predetermined position facing the ophthalmic examination device 100, and the alignment is completed to properly adjust the positional relationship between the left and right test eyes EL, ER and the device, and proceeds to step S1 → step S2 → step S3 → step S4. After starting, the main control unit 141 performs a preliminary measurement (step S1), a main measurement (step S2), and a start setting for the subjective test (step S3). In step S4, after setting the start of the subjective test, the main control unit 141 performs an RG test using an RG chart, so that the left and right test eyes EL, ER are in a state where perfect correction values ​​are prescribed based on the provisionally determined values ​​in the RG test.

[0067] 4, after the perfect correction value is prescribed for the left and right test eyes EL, ER in step S4, the process proceeds from step S5 to step S6. In step S5, the subjective test processing unit 144 controls the rotation angle of the driving unit 122a to set the prism angle to the initial prism angle, and controls the movement of the focusing lens 45 to set the test distance to a constant distance. In step S6, the subjective test processing unit 144 obtains a subjective answer from the subject regarding fusion when the convergence distance and the test distance are matched.

[0068] In the process of FIG. 4, after a subjective answer regarding image fusion in the initial setting is acquired from the subject, the process proceeds to step S7, step S8, and step S9. In step S7, the subjective test processing unit 144 controls the rotation angle of the driving unit 122a to switch the prism angle from the initial prism angle (e.g., 0Δ) to a prism angle that results in a predetermined convergence distance. In step S8, the subjective test processing unit 144 acquires a subjective answer regarding image fusion when the prism angle is switched to a prism angle that results in a predetermined convergence distance from the subject. In step S9, the subjective test processing unit 144 determines whether the prism angle has been changed by all of the predetermined prism angles.

[0069] In the process of FIG. 4, while it is determined in step S9 that the prism angle has not been changed to the final prism angle (for example, -10Δ), the flow of proceeding from step S7 to step S8 to step S9 is repeated. In step S7, the subjective test processing unit 144 controls the rotation angle of the driving unit 122a to switch the prism angle from the current prism angle to the next stage prism angle. The prism angle is switched in stages such as 0Δ→+1Δ, +1Δ→+2Δ, +2Δ→+4Δ, +4Δ→+6Δ, +6Δ→+10Δ, +10Δ→-1Δ, -1Δ→-2Δ, -2Δ→-4Δ, -4Δ→-6Δ, -6Δ→-10Δ. In step S8, the subjective test processing unit 144 obtains a subjective answer regarding the fusion at each stage of the switched prism angle from the subject.

[0070] In the process of FIG. 4, when the subjective test processing unit 144 performs control to make the convergence distance and the test distance coincide with each other in step S5, the objective measurement unit 145 starts objective measurement in parallel with the subjective test process. During the subjective test process, the objective measurement repeats a flow of proceeding from step S10 to step S11 to step S12, and ends when the subjective test process ends (YES in step S9). In step S10, the objective measurement unit 145 acquires an objective refraction value (Ref value) as objective measurement information by Refractive Index measurement. In step S11, the objective measurement unit 145 displays a plurality of objective refraction values ​​(Ref values) acquired at the timing when the prism angle changes. In step S12, the objective measurement unit 145 compares a plurality of Refractive Index values ​​acquired at the timing when the prism angle changes, and calculates an average value.

[0071] 4, when it is determined in step S9 that the prism angle has been changed to the final prism angle (for example, -10Δ), the process proceeds from step S9 to step S13. In step S13, the determination unit 146 determines the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the subjective answer from the subjective test processing unit 144 and the objective refraction value (average refraction value) from the objective measurement unit 145.

[0072] In this way, the flow of the process of evaluating the adaptability to stereoscopic vision is to execute the subjective test process and the objective measurement in parallel, and when the subjective test process is completed, it merges with the objective measurement in step S13. Step S13 determines that the left and right test eyes EL, ER are easily adapted to stereoscopic vision when, for example, the subjective answer that binocular fusion is achieved is obtained regardless of the gradual change in the convergence distance and the change in the average reflex value is suppressed within a predetermined range. Step S13 determines that the left and right test eyes EL, ER are difficult to adapt to stereoscopic vision when, for example, the subjective answer that two targets are seen is obtained due to the gradual change in the convergence distance, and binocular fusion is not achieved, or the change in the average reflex value exceeds a predetermined range.

[0073] [Left eye projected target and right eye projected target (Figure 5)] The left eye projected visual target 8L and the right eye projected visual target 8R set on the display 41 (visual target presenting unit) will be described below with reference to FIG.

[0074] The left eye projected optotype 8L is an optotype projected onto the left eye EL when an evaluation test of stereoscopic vision adaptability is performed by the adaptation evaluation test unit 143. As shown in Fig. 5A, the left eye projected optotype 8L has an asterisk 82 (design) at the center of a square optotype frame 81 made of a liquid crystal frame or the like.

[0075] The right eye projected optotype 8R is an optotype projected onto the right eye ER to be examined when an evaluation test of stereoscopic vision adaptability is performed by the adaptation evaluation test unit 143. As shown in FIG. 5B, the right eye projected optotype 8R has an asterisk 82 (design) at the center of a square optotype frame 81 made of a liquid crystal frame or the like.

[0076] As is clear from a comparison of Figures 5A and 5B, the left eye projected optotype 8L and the right eye projected optotype 8R have an asterisk 82 with the same design, size, and line segment width at the center of the optotype frame 81. The design, size, and line segment width of this asterisk 82 are determined so as to provide an appropriate fusion stimulus to the left and right test eyes EL and ER during fusion, in which images reflected on the retina during binocular vision are combined into one and viewed as a single image.

[0077] In addition, since the fusional stimulus is weak when the target frame 81 is a liquid crystal frame, the fusional stimulus can be increased by using a black frame with a thick line width. Furthermore, the target frame 81 can change the strength of the fusional stimulus by changing the line width of the black frame. Furthermore, the asterisk 82 can change the strength of the fusional stimulus by changing its size or the width of the radial line segments. Furthermore, the asterisk 82 can change the strength of the fusional stimulus by changing the target design to another design.

[0078] [Relationship between test distance and convergence distance (Fig. 6)] The subjective test processing unit 144 prescribes a state in which the convergence distance from the position of the left and right test eyes EL, ER to the convergence position where the two lines of sight intersect changes by controlling the prism angle from the left and right test eyes EL, ER toward the left eye projected target 8L and the right eye projected target 8R. The relationship between the convergence distance and the test distance is described below with reference to FIG. 6.

[0079] The "test distance Lid" refers to the distance along the Z-axis direction from the left and right test eyes EL, ER to the position where the optotype is presented, as shown in Fig. 6. This test distance Lid is realized by the optotype projection system 4 that presents the optotype on the display 41. The test distance Lid can also be said to be the focusing distance when the left and right test eyes EL, ER are focused on the optotype. Here, the test distance Lid is the distance from the line connecting the left and right test eyes EL, ER to the optotype, but is not limited to this and may be the distance from each of the test eyes EL, ER to the optotype.

[0080] The convergence distance is the distance along the Z axis from the positions of the left and right test eyes EL, ER to the convergence position where the two lines of sight intersect. The convergence distance L2 (= examination distance Lid) is the distance along the Z axis from the positions of the left and right test eyes EL, ER to the convergence position R2 where the two lines of sight SL2, SL2 intersect, as shown in Fig. 6. Also, the convergence distance L1 is the distance along the Z axis from the positions of the left and right test eyes EL, ER to the convergence position R1 where the two lines of sight SL1, SL1 intersect, as shown in Fig. 6.

[0081] Here, it is assumed that the test distance is kept at test distance Lid, and the convergence distance is changed from convergence distance L2 to convergence distance L1, as shown by arrow A. At this time, the convergence angle changes from the convergence angle θ2 at which the lines of sight SL2, SL2 intersect to the convergence angle θ1 (>θ2) at which the lines of sight SL1, SL1 intersect, as the convergence distance is changed from the convergence angle θ2 to the convergence angle θ1. Therefore, the left and right test eyes EL, ER generate eyeball movement in a direction in which the left and right test eyes EL, ER move closer together as the convergence angle changes from the convergence angle θ2 to the convergence angle θ1, and this eyeball movement becomes a convergence stimulus.

[0082] On the other hand, since the test distance is kept at the test distance Lid, the focus accommodation distance of the left and right test eyes EL, ER is also constant. Therefore, since the focus accommodation distance of the left and right test eyes EL, ER is kept constant, even if the convergence distance is changed from the convergence distance L2 to the convergence distance L1, the accommodation function due to the change in the test distance Lid does not work, and in principle, when the left and right test eyes EL, ER are objectively measured, the objective refraction value should not change. However, when the left and right test eyes EL, ER are objectively measured, the objective refraction value changes when the left and right test eyes EL, ER are objectively measured, if the accommodation function that changes the curvature of the crystalline lens is activated in response to the convergence stimulus.

[0083] As described above, the relationship in which the test distance is constant and the convergence distance changes is a relationship in which only the convergence stimulus is given to the left and right test eyes EL, ER. Therefore, the adaptability evaluation test unit 143 of the first embodiment is configured to provide two targets at a position at a constant distance from the left and right test eyes EL, ER, and to reproduce the state in which the convergence and accommodation do not match by providing a convergence stimulus by changing the prism angle when the two targets are fused by both eyes. Therefore, the adaptability evaluation test unit 143 can evaluate whether the left and right test eyes EL, ER are easily adapted to stereoscopic vision in which the convergence and accommodation do not match.

[0084] [Stepwise change in vergence distance (Figure 7)] The subjective test processing unit 144 prescribes a state in which the convergence position R (±nΔ) and the convergence distance L (±nΔ) change stepwise in the distance range from a position farther than the test distance Lid to a position closer to the test distance Lid by controlling the prism angle to change stepwise. The change in the convergence distance L (±nΔ) is described below with reference to FIG. 7.

[0085] Fig. 7A shows a state where the convergence distance L(0Δ) to the convergence position R(0Δ) when the left eye projected target 8L and the right eye projected target 8R are fused is matched with the test distance Lid from the left and right test eyes EL, ER to the target positions (step S5). Fig. 7B shows a state where the convergence distance L(+kΔ) to the convergence position R(+kΔ) when the left eye projected target 8L and the right eye projected target 8R are fused is closer than the test distance Lid from the left and right test eyes EL, ER to the target positions. Here, (+kΔ) is any of (+2Δ) to (+10Δ). 7C shows a state in which the convergence distance L(-kΔ) to the convergence position R(-kΔ) when the left eye projected target 8L and the right eye projected target 8R are fused is longer than the test distance Lid from the left and right test eyes EL and ER to the target positions. Note that (-kΔ) is any of (-2Δ) to (-10Δ).

[0086] In step S5 in Fig. 4, the subjective test processing unit 144 performs control to set the test distance Lid to 1 m and also controls the prism angle to the initial prism angle (0Δ). Therefore, the convergence distance L(0Δ) to the convergence position R(0Δ) when the two targets are fused by the left and right test eyes EL, ER coincides with the test distance Lid from the left and right test eyes EL, ER to the target position, as shown in Fig. 7A.

[0087] In step S7 of Fig. 4, the subjective test processing unit 144 performs control to change the prism angle in 11 steps of 0Δ, ±1Δ, ±2Δ, ±4Δ, ±6Δ, and ±10Δ while maintaining the test distance Lid (for example, 1 m). Therefore, when the prism angle is set to -kΔ, the convergence distance L(-kΔ) to the convergence position R(-kΔ) when the two targets are fused by the left and right test eyes EL, ER is farther than the test distance Lid from the left and right test eyes EL, ER to the target position, as shown in Fig. 7C. On the other hand, when the prism angle is set to +kΔ, the convergence distance L(+kΔ) to the convergence position R(+kΔ) when the two targets are fused by the left and right test eyes EL, ER is closer than the test distance Lid from the left and right test eyes EL, ER to the target position, as shown in Fig. 7B.

[0088] In this way, when the subjective test processing unit 144 performs control to change the prism angle in 11 steps, the convergence distance L(-kΔ) is changed stepwise from a state where the convergence distance L(-kΔ) approaches the test distance Lid (FIG. 7C) to a state where the convergence distance L(-kΔ) moves away from the test distance Lid (FIG. 7B). Therefore, the subjective test processing unit 144 can provide a stepwise changing convergence stimulus to the left and right test eyes EL, ER by changing the convergence distance L(±nΔ) stepwise from a state farther away from the test distance Lid to a state closer to the test distance Lid.

[0089] [Measurement of time changes in accommodation and vergence while observing 3D images (Figure 8)] The inventors measured the time changes in accommodation and convergence for the test eyes of the healthy group and the stereoscopic image fatigue group. The measurement of the time changes in accommodation and convergence will be described below with reference to Figs. 8A to 8E.

[0090] The prism angle of the target is changed until the test distance is 60 cm and the parallax distance is 4 cm (6.7Δ, the protrusion amount at this time is 24 cm). As shown in Figure 8A, the measurement conditions are as follows: parallax 0 degrees is maintained for 1 to 2 seconds, the prism angle is changed from 0Δ to 6.7Δ over 2 seconds, and then the prism angle is fixed at 6.7Δ.

[0091] The measurement results for a normal eye are shown in Figure 8B. When the prism angle is changed from 0Δ to 6.7Δ over 2 seconds, the convergence (MA) value decreases in accordance with the change in prism angle. When the prism angle is fixed at 6.7Δ, the convergence (MA) value fluctuates slightly, but the value at the protruding position after the decrease is maintained. "MA (short for Meter Angle)" is the unit of convergence force. When the prism angle is changed from 0Δ to 6.7Δ over 2 seconds, the focus adjustment function for the protruding position works and the value decreases. However, when the prism angle is fixed at 6.7Δ, the decreased value returns to the original value with good response, and the original value is maintained thereafter. "D (diopter)" is the unit of refractive power that converts refractive power into a number.

[0092] The measurement results of the stereoscopic image fatigue group are shown in Figures 8D and 8E. The measurement results of convergence (MA) and refraction (D) in Figure 8D are examples of subjects who experienced headaches and eye fatigue after watching an IMAX movie ("IMAX" is a registered trademark) for about 15 minutes and stopped watching. Here, "IMAX movie" refers to a movie with high-definition images that uses a special standard (a standard in which the area of ​​the film used per frame is expanded from the usual 35 mm to 70 mm) moving image film and is screened by a special projection system. Both the convergence (MA) and refraction (D) show chaotic characteristics, including large value fluctuations and interruptions in the middle of the value, regardless of whether the prism angle is changed or maintained.

[0093] The measurement results of convergence (MA) and refraction (D) in Figure 8E are examples of subjects who felt strong drowsiness and eye fatigue after watching a 3D movie for about 30 minutes, and stopped watching. Here, "3D movie" refers to a movie in which the image projected on the screen is viewed in three dimensions by wearing special glasses. When the prism angle of convergence (MA) is changed from 0Δ to 6.7Δ over 2 seconds, the value at the start of the change is lower than that of a normal eye example, but the value decreases following the change in the prism angle. When the prism angle of convergence (MA) is fixed at 6.7Δ, the value is maintained according to the protrusion position, but the value is interrupted midway, showing a disordered characteristic. When the prism angle of refraction (D) is changed from 0Δ to 6.7Δ over 2 seconds, the focus adjustment function for this protrusion position is activated, and the value decreases. When the prism angle (D) is fixed at 6.7Δ, the refractive index (D) shows disturbed characteristics due to fluctuations in the value that attempt to return the reduced value to the original value and interruptions in the value along the way.

[0094] An example of the analysis result of the time-varying frequency of the refraction (D) in the healthy group and the fatigue group is shown in FIG. 8E. When comparing the amplitude of the healthy group and the fatigue group, the amplitude (fluctuation range) is larger in the fatigue group than in the healthy group in all frequency bands of 0.5-1.5 Hz, 1.5-2.5 Hz, 2.5-3.5 Hz, and 3.5-4.5 Hz. Therefore, when the amplitude (fluctuation range) of the time-varying frequency of the refraction (D) of the subject's eye is measured, the analysis result example shown in FIG. 8E can be used for data that confirms that the subject's eye belongs to the fatigue group based on the magnitude of the fluctuation range. In particular, in the low frequency band, the amplitude can be used for data that confirms that the subject's eye belongs to the fatigue group based on the magnitude of the amplitude.

[0095] For example, in the low frequency band of 0.5 to 1.5 Hz, as shown in FIG. 8E, the threshold for judging whether the subject's eye belongs to the fatigue group is set to an amplitude of about 0.2 to 0.3. In this case, a stereoscopic adaptation evaluation test is performed on a specific subject's eye, and objective refraction data is obtained in a time series along the time axis, and the amplitude of the objective refraction characteristic of the data in the low frequency band of 0.5 to 1.5 Hz is measured. If the measured amplitude of the low frequency band is equal to or greater than the predetermined judgment threshold, the subject's eye can be judged to belong to the fatigue group. Here, the test is performed by changing the prism angle with the internal target, but the present invention is not limited to this. For example, a naked eye type stereoscopic display is installed to present images with different line of sight angles to the left and right eyes, and a similar test can be performed.

[0096] [Stereoscopic Vision Adaptability Assessment (Figure 9)] The objective measurement unit 145 measures the eye characteristics of the left and right test eyes EL, ER at each stage of the convergence distance L (±nΔ) a predetermined number of times, and obtains an objective refraction average value by averaging the objective refraction values ​​obtained at each stage a predetermined number of times as objective measurement information. The function of determining the adaptability to stereoscopic vision is described below with reference to FIG. 9.

[0097] Figure 9 shows the relationship between the prism angle and the objective refraction value when the average objective refraction value was obtained for each stage of the convergence distance L (±nΔ) for multiple subjects. The vertical axis is the objective refraction value, and the unit of each value is diopter (D). The horizontal axis is the prism angle, and the unit of each value is prism (Δ), but it may be converted to diopter (D) or the convergence angle (MA) expressed as the reciprocal of the convergence distance.

[0098] Among the relationship characteristics in Fig. 9, the first group G1 shows a characteristic in which the numerical value of the objective refraction value increases in response to the change in the prism angle when the prism angle is changed in seven steps from -1Δ→0Δ→+1Δ→+2Δ→+4Δ→+6Δ→+10Δ. In other words, the first group G1 has a characteristic in which the numerical value of the objective refraction value increases to about D=3.0 when the prism angle is changed from +2Δ→+4Δ→+6Δ→+10Δ.

[0099] For this reason, it is estimated that the subjects belonging to the first group G1 are given a convergence stimulus due to the change in the convergence distance, and a focus accommodation response is induced in the left and right test eyes EL, ER. Therefore, it can be determined that the subjects belonging to the first group G1 have difficulty in adapting the left and right test eyes EL, ER to stereoscopic vision due to a mismatch between the refractive value and the target position caused by convergence.

[0100] On the other hand, the second group G2 among the relationship characteristics in Fig. 9 shows a characteristic in which the numerical value of the objective refraction value remains constant when the prism angle is changed in seven steps from -1Δ→+0Δ→+1Δ→+2Δ→+4Δ→+6Δ→+10Δ. In other words, the second group G2 has a characteristic in which the numerical value of the objective refraction value is suppressed to a value of D<1.0 or less even when the prism angle is changed from +2Δ→+4Δ→+6Δ→+10Δ.

[0101] Therefore, it is estimated that the subjects belonging to the second group G2 do not induce a focus accommodation response in the left and right test eyes EL, ER, even though the convergence stimulus is given by the change in the convergence distance. Therefore, the subjects belonging to the second group G2 can be judged to have a high adaptability to stereoscopic vision in the left and right test eyes EL, ER because there is no mismatch between the refractive value and the target position due to convergence.

[0102] [Effects of ophthalmic examination device and ophthalmic examination method] (1) The ophthalmic examination device 100 includes a target projection system 4 having a target presentation unit (display 41) that presents fixation targets to the left and right test eyes EL, ER, objective measurement optical systems 6, 7 that objectively measure the ocular characteristics of the left and right test eyes EL, ER, and a control unit 140 that controls each unit of the device. The fixation targets are a left eye projected target 8L and a right eye projected target 8R that have the same design (asterisk 82) and are projected onto each of the left and right test eyes EL, ER. The target presentation unit presents the left eye projected target 8L and the right eye projected target 8R at target positions that are a certain test distance Lid away from the left and right test eyes EL, ER. The target projection system 4 prescribes a state in which the convergence distance L (±nΔ) from the position of the left and right test eyes EL, ER to the convergence position R (±nΔ) where the two lines of sight intersect is changed by changing the line of sight angle (prism angle) from the left and right test eyes EL, ER to the left eye projected target 8L and the right eye projected target 8R. When the control unit 140 attempts fusion with the left and right test eyes EL, ER in response to the change in the convergence distance L (±nΔ), it measures the eye characteristics of the left and right test eyes EL, ER using the objective measurement optical system and obtains objective refraction values ​​as objective measurement information. Therefore, the ophthalmic examination apparatus 100 can evaluate whether the left and right test eyes EL, ER are easily adapted to stereoscopic vision in which a mismatch between convergence and accommodation occurs.

[0103] (2) The ophthalmic examination device 100 is an objective measurement device with a subjective test function. The control unit 140 has an adaptation evaluation test unit 143 that evaluates the adaptability of the left and right test eyes EL, ER, and the adaptation evaluation test unit 143 includes a subjective test processing unit 144 and an objective measurement unit 145. The subjective test processing unit 144 presents a left eye projected optotype 8L and a right eye projected optotype 8R at a target position that is a certain test distance Lid away from the left and right test eyes EL, ER. By controlling to change the line of sight angle (prism angle) from the left and right test eyes EL, ER toward the left eye projected optotype 8L and the right eye projected optotype 8R, a state in which the convergence distance L (±nΔ) from the position of the left and right test eyes EL, ER to the convergence position R (±nΔ) where the two lines of sight intersect is changed is prescribed. The objective measurement unit 145 is executed in parallel with the processing in the subjective test processing unit 144, and when fusion is attempted with the left and right test eyes EL, ER in response to a change in the convergence distance L (±nΔ), the objective measurement optical systems 6, 7 measure the eye characteristics of the left and right test eyes EL, ER, and obtain objective refraction values ​​as objective measurement information. Therefore, the ophthalmic examination apparatus 100 can save the effort and time required for the subjective test compared to when the subjective test processing is performed by manual operation. In addition, the ophthalmic examination apparatus 100 can accurately evaluate whether the left and right test eyes EL, ER are easily adapted to stereoscopic vision by simultaneously executing the subjective test processing and the objective measurement in parallel processing.

[0104] (3) The ophthalmic examination apparatus 100 includes a left measurement head unit 122L incorporating a left eye projection target 8L and a left measurement optical system 125L corresponding to the left test eye EL, and a right measurement head unit 122R incorporating a right eye projection target 8R and a right measurement optical system 125R corresponding to the right test eye ER. The subjective test processing unit 144 controls to change the line of sight angle (prism angle) by changing the rotation angle of the left measurement head unit 122L and the right measurement head unit 122R in opposite directions. Therefore, when the subjective test processing unit 144 changes the convergence distance L (±nΔ) by controlling the rotation of the left measurement head unit 122L and the right measurement head unit 122R, the visual axis from the left and right test eyes EL, ER can be kept in agreement with the optical axis in the left measurement optical system 125L and the right measurement optical system 125R. In addition, by aligning the visual axis and the optical axis, the ophthalmic examination apparatus 100 can measure the eye position and gaze direction from the anterior eye image to confirm whether or not the left and right test eyes EL, ER are able to objectively achieve binocular vision.

[0105] (4) The subjective test processing unit 144 acquires a subjective answer from the subject when the left and right test eyes EL, ER are attempted to fuse in response to a change in the convergence distance. The adaptation evaluation test unit 143 has, in addition to the subjective test processing unit 144 and the objective measurement unit 145, a judgment unit 146 that judges the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the subjective answer from the subject acquired by the subjective test processing unit 144 and the objective refraction value acquired by the objective measurement unit 145. Therefore, the judgment unit 146 can confirm whether or not the left and right test eyes EL, ER are subjectively fused when judging the adaptability of the left and right test eyes EL, ER to stereoscopic vision.

[0106] (5) The judgment unit 146 judges that the left and right test eyes EL, ER are easily adapted to stereoscopic vision when a positive subjective response is obtained for binocular fusion in response to a change in the convergence distance L (±nΔ) and the change range of the objective refraction value is suppressed within a predetermined range. Therefore, the judgment unit 146 can judge that the left and right test eyes EL, ER are easily adapted to stereoscopic vision when a convergence stimulus is given by a change in the convergence distance L (±nΔ) and subjective fusion is possible and the focus accommodation response of the left and right test eyes EL, ER is slow.

[0107] (6) When a negative subjective response is obtained for binocular fusion in response to a change in the convergence distance L (±nΔ) and the change in the objective refraction value exceeds a predetermined range, the determination unit 146 determines that the left and right test eyes EL, ER are difficult to adapt to stereoscopic vision. Therefore, when a convergence stimulus is given by a change in the convergence distance L (±nΔ), subjective fusion is difficult and a focus accommodation reaction occurs in the left and right test eyes EL, ER, the determination unit 146 can determine that the left and right test eyes EL, ER are difficult to adapt to stereoscopic vision.

[0108] (7) The adaptability evaluation test unit 143 has a judgment unit 146 that judges the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the objective refraction value acquired by the objective measurement unit 145, in addition to the subjective test processing unit 144 and the objective measurement unit 145. The judgment unit 146 measures the amplitude, which is the fluctuation range of the refraction value characteristic on the time axis of the objective refraction value acquired by the objective measurement unit 145, and judges that the left and right test eyes EL, ER belong to the fatigue group when the amplitude is equal to or greater than the judgment threshold value when the fluctuation frequency of the refraction value characteristic is in the low frequency band. Therefore, the judgment unit 146 can judge that the left and right test eyes EL, ER belong to the fatigue group that is difficult to adapt to stereoscopic vision based on the refraction value characteristic on the time axis of the acquired objective refraction value.

[0109] (8) The subjective test processing unit 144 prescribes a state in which the convergence distance L (±nΔ) changes stepwise in a distance range from a position farther than the test distance Lid to a position closer than the test distance Lid by controlling the angle of gaze (prism angle) from the left and right test eyes EL, ER toward the left eye projected target 8L and the right eye projected target 8R to change stepwise. The objective measurement unit 145 measures the eye characteristics of the left and right test eyes EL, ER a predetermined number of times at each stage of the convergence distance L (±nΔ), and obtains an objective refraction average value obtained by averaging the objective refraction values ​​obtained at each stage a predetermined number of times as objective measurement information. Therefore, the subjective test processing unit 144 can give a stepwise changing convergence stimulus to the left and right test eyes EL, ER. In addition, the objective measurement unit 145 can obtain information representing the amount of accommodation response of the left and right test eyes EL, ER to the stepwise changing convergence stimulus from the objective refraction average value, which is the objective measurement information.

[0110] (9) The ophthalmic examination method includes a complete correction prescription step (steps S1 to S4), a target presentation step (step S5), a convergence distance control step (steps S7 and S9), an accommodation response measurement step (steps S10 to S12), and a judgment step (step S13). In the complete correction prescription step, the left and right test eyes EL, ER are placed in a state in which a complete correction value is prescribed in a subjective test. In the target presentation step, following the prescription of the complete correction value, a left eye projected target 8L and a right eye projected target 8R having the same pattern (asterisk 82) are presented on the target presentation unit (display 41) at target positions a certain test distance Lid away from the left and right test eyes EL, ER. The convergence distance control step prescribes a state in which the convergence distance L(0Δ) changes from the position of the left and right test eyes EL, ER to the convergence position R(0Δ) where the two lines of sight intersect, by controlling the change in the line of sight angle (prism angle) from the left and right test eyes EL, ER to the left eye projected visual target 8L and the right eye projected visual target 8R. The accommodation reaction amount measurement step is executed in parallel with the control of the convergence distance L(±nΔ), and when fusion is attempted with the left and right test eyes EL, ER in response to the change in the convergence distance L(±nΔ), the ocular characteristics of the left and right test eyes EL, ER are measured by the objective measurement optical systems 6, 7, and objective refraction values ​​are obtained as objective measurement information. The judgment step judges the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the objective refraction values. Therefore, the ophthalmic examination method (Fig. 4) can evaluate whether the left and right test eyes EL, ER are easily adapted to stereoscopic vision, in which a mismatch between convergence and accommodation occurs. In addition, the ophthalmic examination method (Fig. 4) can also train the left and right test eyes EL, ER to improve their ability to adapt to stereoscopic vision by utilizing the convergence distance control step and having the left and right test eyes EL, ER repeatedly observe images with the convergence distance L (±nΔ) shifted, so that they can become accustomed to the images.

[0111] (10) The ophthalmic examination method includes a subjective answer acquisition step (steps S6 and S8) for acquiring a subjective answer regarding fusion from the subject when fusion is attempted with the left and right test eyes EL, ER in response to a change in convergence distance. The determination step determines the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the subjective answer and the objective refraction value. Therefore, the ophthalmic examination method (FIG. 4) can confirm whether or not fusion is subjectively achieved when determining the adaptability of the left and right test eyes EL, ER to stereoscopic vision. EXAMPLES

[0112] Example 2 is an example of prescribing a state in which the convergence distance L (±nΔ) changes steplessly within a distance range from a position farther than the test distance Lid to a position closer to the test distance Lid. Note that Example 2 has the same configuration as that of Example 1 in Figs. 1, 2, and 3 with respect to "overall configuration of the device," "configuration of the optical system," and "configuration of the control unit," and therefore illustrations and explanations thereof are omitted.

[0113] [Configuration and operation flow of the process for evaluating the ability to adapt to stereoscopic vision (Figure 10)] The configuration and flow of operations of the process for evaluating the adaptability to stereoscopic vision, which is executed in the adaptability evaluation test unit 143, will be described below with reference to the flowchart shown in FIG. It should be noted that steps S21, S22, S23, S24, S25, and S26 are the same processing steps as steps S1, S2, S3, S4, S5, and S6 in FIG. 4, respectively, and therefore their explanation will be omitted.

[0114] Step S27 is a prism angle changing process step in which the subjective test processing unit 144 controls the rotation angle of the driving unit 122a to change the prism angle steplessly from the initial prism angle (e.g., 0Δ) or the previous prism angle while maintaining the test distance (e.g., 1 m). The prism angle is changed steplessly, for example, from 0Δ to +10Δ, and then further changed steplessly from 0Δ to -10Δ. For example, when the initial prism angle is 0Δ, it is changed steplessly to -10Δ.

[0115] Step S28 is a subjective answer step in which the subjective test processing unit 144 acquires a subjective answer regarding the fusion of the left eye projected optotype and the right eye projected optotype when the left and right test eyes EL, ER are attempted to fuse with respect to a stepless change in the convergence distance from the subject. As the subjective answer, for example, when the convergence distance is changing steplessly, an answer as to whether the optotypes are seen as one by fusion is acquired at a predetermined time interval. When the subjective answer is prompted, the change of the prism angle may be temporarily stopped.

[0116] Step S29 is a final prism angle determination step in which the subjective test processing unit 144 determines whether the prism angle has reached the final prism angle (for example, ±10Δ). If the determination in step S29 is NO, the process returns to step S27, and if the determination in step S29 is YES, the process proceeds to step S33. Note that step S29 may be configured to set the time required for the prism angle to reach the final prism angle at a stepless change speed, and to determine whether the set time has elapsed.

[0117] Steps S27 and S29 correspond to a convergence distance control step for prescribing a state in which the convergence distance from the positions of the left and right test eyes EL, ER to the convergence position where the two lines of sight intersect is changed by controlling to change the prism angle from the left and right test eyes EL, ER toward the left eye projection target and the right eye projection target. Steps S26 and S28 correspond to a subjective answer acquisition step for acquiring a subjective answer regarding fusion from the subject when fusion is attempted with the left and right test eyes EL, ER in response to the change in the convergence distance.

[0118] Step S30 is a refraction measurement step in which the objective measurement unit 145 measures the ocular characteristics of the left and right test eyes EL, ER with respect to the change in the convergence distance using the objective measurement optical system, and acquires the objective refraction value in a time series as the objective measurement information. Step S31 is a refraction value display step in which the objective measurement unit 145 displays the objective refraction value (refraction value) in a time series acquired while the prism angle is changed steplessly. Step S32 is a time series refraction value comparison step in which the objective measurement unit 145 compares the refraction values ​​in a time series acquired while the prism angle is changed steplessly. These steps S30 to S32 are executed in parallel with the control of the convergence distance, and correspond to an accommodation reaction amount measurement step in which, when fusion is attempted with the left and right test eyes EL, ER with respect to the change in the convergence distance, the ocular characteristics of the left and right test eyes EL, ER are measured using the objective measurement optical system, and the objective refraction value is acquired as the objective measurement information.

[0119] Step S33 is a step in which the judgment unit 146 judges the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the subjective answer from the subjective test processing unit 144 and the objective refraction value (time-series refraction value) from the objective measurement unit 145. When the judgment of the adaptability of stereoscopic vision is completed, step S33 proceeds to the end. This step S33 corresponds to a judgment step in which the adaptability of the left and right test eyes EL, ER to stereoscopic vision is judged based on the subjective answer and the objective refraction value.

[0120] The flow of the action of each step is explained as follows. In the process of FIG. 10, after a subjective answer regarding image fusion when the convergence distance and the test distance are matched is acquired from the subject in step S26, the process proceeds to step S27, step S28, and step S29. In step S27, the subjective test processing unit 144 performs rotation angle control of the driving unit 122a to continuously switch the prism angle from the initial prism angle (e.g., 0Δ). In step S28, the subjective test processing unit 144 acquires a subjective answer regarding image fusion when the prism angle is switched to (e.g., +1Δ) from the subject. In step S29, the subjective test processing unit 144 determines whether the prism angle is continuously changed to a final prism angle (e.g., +10Δ) in the direction in which the convergence distance decreases, then changed to an initial prism angle (e.g., 0Δ), and then changed in the direction in which the convergence distance increases to the final prism angle (e.g., -10Δ).

[0121] 10, while it is determined in step S29 that the prism angle has not been changed to the final prism angle (for example, ±10Δ), the flow of proceeding from step S27 to step S28 to step S29 is repeated. In step S27, the subjective test processing unit 144 controls the rotation angle of the driving unit 122a to switch the prism angle steplessly. In step S28, while the prism angle is being changed steplessly, the subjective test processing unit 144 acquires subjective answers regarding image fusion at predetermined time intervals from the subject.

[0122] In the process of FIG. 10, when the subjective test processing unit 144 performs control to make the convergence distance and the test distance coincide with each other in step S25, the objective measurement unit 145 starts objective measurement in parallel with the subjective test process. During the subjective test process, the objective measurement repeats a flow of proceeding from step S30 to step S31 to step S32, and ends when the subjective test process ends (YES in step S29) in accordance with the end of the subjective test process. In step S30, the objective measurement unit 145 acquires objective refraction values ​​(Ref values) in a time series as objective measurement information by Refractive Index measurement. In step S31, the objective measurement unit 145 displays the acquired Refractive Index values ​​in a time series. In step S32, the objective measurement unit 145 compares the Refractive Index values ​​in a time series.

[0123] 10, when it is determined in step S29 that the prism angle has reached the final prism angle (for example, ±10Δ), the process proceeds from step S29 to step S33. In step S33, the determination unit 146 determines the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the subjective answer from the subjective test processing unit 144 and the time-series objective refraction value from the objective measurement unit 145.

[0124] In this way, the flow of the process for evaluating the adaptability to stereoscopic vision is to execute the subjective test process and the objective measurement in parallel, and when the subjective test process is completed, it merges with the objective measurement in step S33. Step S33 determines that the left and right test eyes EL, ER are easily adapted to stereoscopic vision when, for example, a subjective answer is obtained that binocular fusion has been achieved regardless of the stepless change in the convergence distance, and the change in the objective refraction value over time is suppressed within a predetermined range. Step S33 determines that the left and right test eyes EL, ER are difficult to adapt to stereoscopic vision when, for example, a subjective answer is obtained that the visual target appears as two objects due to the stepless change in the convergence distance, and binocular fusion has not been achieved, or the change in the objective refraction value over time exceeds a predetermined range. Furthermore, by obtaining the objective refraction value over time in response to the convergence stimulus, the fluctuation of the objective refraction value can also be measured. For example, frequency analysis can be performed to determine that adaptation to stereoscopic vision is difficult when the fluctuation range in a particular frequency band is large.

[0125] [Effects of ophthalmic examination equipment] (11) The subjective test processing unit 144 prescribes a state in which the convergence distance L (±nΔ) changes steplessly in a distance range from a position farther than the test distance Lid to a position closer to the test distance Lid by controlling the line of sight angle (prism angle) from the left and right test eyes EL, ER toward the left eye projected target 8L and the right eye projected target 8R to change steplessly. The objective measurement unit 145 measures the eye characteristics of the left and right test eyes EL, ER in a state in which the convergence distance L (±nΔ) changes steplessly, and obtains objective refraction values ​​obtained in a time series as objective measurement information. Therefore, the subjective test processing unit 144 can give a convergence stimulus that changes steplessly to the left and right test eyes EL, ER. In addition, the objective measurement unit 145 can measure the fluctuation of the objective refraction value that represents the fluctuation of the accommodation response amount of the left and right test eyes EL, ER to the convergence stimulus that changes steplessly.

[0126] The ophthalmic examination apparatus 100 and the ophthalmic examination method of the first and second embodiments (FIGS. 4 and 10) have been described above with reference to the drawings. However, the specific configurations of the ophthalmic examination apparatus and the ophthalmic examination method of the present invention are not limited to those of the first and second embodiments, and design changes and additions are permitted as long as they do not deviate from the gist of the invention according to each claim of the claims.

[0127] The ophthalmic examination device 100 of the first and second embodiments is an example of an objective measurement device with a subjective test function using an internal target, which is equipped with a target presentation function, a phoropter function, and an autorefraction and keratoconstriction measurement function. However, the ophthalmic examination device is not limited to the device configuration examples of the first and second embodiments. For example, the ophthalmic examination device may be configured as a composite device including a target projection device that presents a real target and prescribes a state in which the convergence distance changes, and a device having a phoropter function and an autorefraction measurement function.

[0128] The ophthalmic examination apparatus 100 of the first and second embodiments shows an example in which the control for changing the line of sight angle (prism angle) is performed by changing the rotation angle for rotating the left measurement head unit 122L and the right measurement head unit 122R in mutually opposite directions. The ophthalmic examination apparatus is not limited to the example of the line of sight angle control of the first and second embodiments. For example, the ophthalmic examination apparatus may be an example in which the control for changing the line of sight angle (prism angle) is performed by inserting a prism lens at a position on the optical axis from the left and right subject eyes of the visual target projection system to the visual target presenting unit.

[0129] The determination unit 146 in the first and second embodiments has been described as an example for determining the adaptability of the left and right test eyes EL, ER to stereoscopic vision based on the subjective answer from the test subject acquired by the subjective test processing unit 144 and the objective refraction value acquired by the objective measurement unit 145. However, the determination unit is not limited to the examples of the determination unit in the first and second embodiments. The determination unit may be, for example, an example for determining the adaptability of the left and right test eyes to stereoscopic vision based only on the objective refraction value.

[0130] The subjective test processing unit 144 of the first embodiment performs control to change the line of sight angle (prism angle) stepwise, and obtains an average objective refraction value by averaging a predetermined number of objective refraction values ​​obtained at each step. The subjective test processing unit 144 of the second embodiment performs control to change the line of sight angle (prism angle) steplessly, and obtains an objective refraction value obtained in a time series. However, the subjective test processing unit is not limited to the first and second embodiments. The subjective test processing unit may perform control to change the line of sight angle (prism angle) stepwise, and obtain an objective refraction value obtained in a time series despite the stepwise control.

[0131] The ophthalmic examination apparatus and the ophthalmic examination method of the present invention are also acceptable in the following respects. (a) The range of prism angles may be determined, for example, by assuming the actual values ​​of the 3D image to be viewed or the head-mounted display, so that it is possible to determine whether the range is suitable for a specific stereoscopic image. (b) Images of the anterior eye segment may be continuously acquired during the measurement of the objective refraction value, and alignment may be automatically performed when the alignment is misaligned. (c) The ability of the left and right test eyes EL, ER to adapt to stereoscopic vision may be determined by acquiring anterior eye images in chronological order or at the timing when the prism angle changes, and determining that the eyes are not able to adapt to stereoscopic vision when a near vision reaction in which the pupils constrict when the convergence distance becomes closer occurs to a predetermined extent or more. (d) The ability of the left and right eyes EL and ER to adapt to stereoscopic vision may be judged by combining a plurality of criteria to calculate an adaptation coefficient to stereoscopic vision. [Explanation of symbols]

[0132] 100 Ophthalmic examination equipment 122L Left measuring head 122R Right measuring head 125L Left measurement optical system 125R Right measurement optical system 122a Drive unit 4 Visual target projection system 41 Display (visual target presentation unit) 6 Reflector measurement projection system (objective measurement optical system) 7 Reflector measurement receiving system (objective measurement optical system) 140 Control section 141 Main control unit 143 Adaptation Assessment and Inspection Department 144 Self-examination Processing Unit 145 Objective Measurement Department 146 Judgment section 8L left eye projection optotype 8R Right eye projection optotype

Claims

1. a target projection system having a target presenting unit for presenting fixation targets to the left and right eyes to be examined; an objective measurement optical system that objectively measures ocular characteristics of the left and right test eyes; A control unit that controls each unit of the device, the fixation target is a left eye projected target and a right eye projected target having the same design, which are projected onto the left and right eyes, respectively; the optotype presenting unit presents the left eye projected optotype and the right eye projected optotype at optotype positions spaced a certain test distance from the left and right eyes to be examined, the target projection system prescribes a state in which a convergence distance from the positions of the left and right test eyes to a convergence position where the two lines of sight intersect is changed by changing an angle of sight lines from the left and right test eyes toward the left-eye projected target and the right-eye projected target, When fusion is attempted using the left and right test eyes in response to a change in the convergence distance, the control unit measures the eye characteristics of the left and right test eyes using the objective measurement optical system and acquires an objective refraction value as objective measurement information. An ophthalmic examination apparatus comprising:

2. 2. The ophthalmic examination apparatus according to claim 1, The ophthalmic examination apparatus is an objective measurement apparatus having a subjective examination function, The control unit has an adaptation evaluation test unit that evaluates the adaptability of the left and right test eyes, and the adaptation evaluation test unit includes a subjective test processing unit and an objective measurement unit, the subjective test processing unit presents the left eye projection optotype and the right eye projection optotype at optotype positions that are a certain test distance away from the left and right eyes to be examined, and prescribes a state in which a convergence distance from the positions of the left and right eyes to a convergence position where two lines of sight intersect is changed by controlling to change an angle of sight lines from the left and right eyes to the left eye projection optotype and the right eye projection optotype; The objective measurement unit is executed in parallel with the processing in the subjective test processing unit, and when fusion is attempted with the left and right test eyes in response to a change in the convergence distance, the objective measurement unit measures the ocular characteristics of the left and right test eyes by the objective measurement optical system, and acquires an objective refraction value as objective measurement information. An ophthalmic examination apparatus comprising:

3. 3. The ophthalmic examination apparatus according to claim 2, the ophthalmic examination apparatus includes a left measurement head portion incorporating the left-eye projected optotype and a left measurement optical system corresponding to the left eye to be examined, and a right measurement head portion incorporating the right-eye projected optotype and a right measurement optical system corresponding to the right eye to be examined, The subjective test processing unit controls the change of the line of sight angle by changing a rotation angle by which the left measurement head unit and the right measurement head unit are rotated in opposite directions to each other. An ophthalmic examination apparatus comprising:

4. 3. The ophthalmic examination apparatus according to claim 2, the subjective test processing unit acquires a subjective response from the subject when the subject attempts fusion of the left and right eyes to the change in the convergence distance; The adaptation evaluation test unit includes, in addition to the subjective test processing unit and the objective measurement unit, a determination unit that determines the adaptability of the left and right eyes to stereoscopic vision based on the subjective response from the subject acquired by the subjective test processing unit and the objective refraction value acquired by the objective measurement unit. An ophthalmic examination apparatus comprising:

5. 5. The ophthalmic examination apparatus according to claim 4, The determining unit determines that the left and right test eyes are easily adapted to stereoscopic vision when a positive subjective response is obtained for binocular fusion with respect to the change in the convergence distance and the change range of the objective refraction value is suppressed within a predetermined range. An ophthalmic examination apparatus comprising:

6. 5. The ophthalmic examination apparatus according to claim 4, The determining unit determines that the left and right test eyes are difficult to adapt to stereoscopic vision when a negative subjective response is obtained for binocular fusion with respect to the change in the convergence distance and the change in the objective refraction value exceeds a predetermined range. An ophthalmic examination apparatus comprising:

7. 3. The ophthalmic examination apparatus according to claim 2, The adaptation evaluation examination unit has a determination unit that determines the adaptability of the left and right test eyes to stereoscopic vision based on the objective refraction value acquired by the objective measurement unit, in addition to the subjective examination processing unit and the objective measurement unit, The determination unit measures an amplitude, which is a fluctuation range of a refraction value characteristic over a time axis of the objective refraction value acquired by the objective measurement unit, and when a fluctuation frequency of the refraction value characteristic is in a low frequency band, if the amplitude is equal to or greater than a determination threshold value, determines that the left and right test eyes belong to a fatigue group. An ophthalmic examination apparatus comprising:

8. An ophthalmic examination apparatus according to any one of claims 2 to 7, the subjective test processing unit prescribes a state in which the convergence distance changes stepwise within a distance range from a position farther than the test distance to a position closer than the test distance by controlling to gradually change a line of sight angle from the left and right test eyes toward the left eye projected target and the right eye projected target, The objective measurement unit measures the eye characteristics of the left and right test eyes a predetermined number of times at each stage of the convergence distance, and obtains an average objective refraction value obtained by averaging the objective refraction values ​​obtained at each stage a predetermined number of times as objective measurement information. An ophthalmic examination apparatus comprising:

9. An ophthalmic examination apparatus according to any one of claims 2 to 7, the subjective test processing unit prescribes a state in which the convergence distance changes steplessly within a distance range from a position farther than the test distance to a position closer than the test distance by controlling a line of sight angle from the left and right test eyes toward the left eye projected target and the right eye projected target to be changed steplessly, The objective measurement unit measures the eye characteristics of the left and right eyes to be examined while the convergence distance is continuously changed, and acquires objective refraction values ​​obtained in a time series as objective measurement information. An ophthalmic examination apparatus comprising:

10. a target projection system having a target presenting unit for presenting fixation targets to the left and right eyes to be examined; an objective measurement optical system that objectively measures ocular characteristics of the left and right test eyes; A control unit that controls each unit of the device, The control unit is a perfect correction prescription step for prescribing the right and left test eyes to a state where a perfect correction value in a subjective test is prescribed; a target presenting step of presenting a left eye projected target and a right eye projected target having the same pattern on the target presenting unit at a target position a certain test distance away from the left and right eyes to be examined; a convergence distance control step of prescribing a state in which a convergence distance from the positions of the left and right eyes to a convergence position where the two lines of sight intersect is changed by controlling to change an angle of sight lines from the left and right eyes to the left eye projected target and the right eye projected target; an accommodation reaction amount measuring step, which is executed in parallel with the control of the convergence distance, and measures the eye characteristics of the left and right test eyes by the objective measurement optical system when fusion is attempted with respect to a change in the convergence distance, and obtains an objective refraction value as objective measurement information; and a determining step of determining the adaptability of the left and right examinee's eyes to stereoscopic vision based on the objective refraction value. The ophthalmic examination method according to the present invention is characterized in that

11. 11. The ophthalmic examination method according to claim 10, The ophthalmologic examination method includes a subjective answer acquisition step of acquiring a subjective answer regarding the fusion from a subject when the subject attempts fusion with the left and right test eyes in response to a change in the convergence distance, The determining step determines the adaptability of the left and right eyes to stereoscopic vision based on the subjective response and the objective refraction value. The ophthalmic examination method according to the present invention is characterized in that

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