Ophthalmologic apparatus

Abstract

To provide an ophthalmologic apparatus capable of appropriately measuring convergence accommodation.SOLUTION: An ophthalmologic apparatus 100 includes a target presentation unit (41) for presenting a target 8 to right and left eyes E to be examined and objective measurement optical systems 6 and 7 for objectively measuring eye characteristics of the two eyes E to be examined. The target presentation unit changes a convergence position R where two visual lines intersect with each other from the position of the two eyes E to be examined and presents the target 8 in a state that a pin hole (50) is arranged at a position conjugate with the pupils of the two eyes E to be examined. The objective measurement optical systems 6 and 7 acquire an objective refractive power of the right and left eyes E to be examined in a state that the target 8 presented at the convergence position R is fused while the target presentation unit is arranging the pin hole.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to ophthalmic devices. [Background technology]

[0002] There are known ophthalmic devices that measure ocular information while a fixation target is viewed with both eyes (see, for example, Patent Documents 1 and 2). This conventional ophthalmic device can measure ocular information of each subject's eye while a common fixation target is presented. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-069201 A [Patent Document 2] Patent Publication No. 2022-038942 Summary of the Invention [Problem to be solved by the invention]

[0004] However, it is known that the subject's eye not only adjusts to focus according to the distance (presentation distance) to the fixation target in a binocular vision state, but also generates convergence-induced accommodation (convergence accommodation) in accordance with the direction of the fixation target in order to fuse the fixation target. Since the convergence accommodation is based on binocular vision, accommodation according to the distance occurs at the same time. For this reason, it is difficult for conventional ophthalmic devices to appropriately measure convergence accommodation.

[0005] The present disclosure has been made in consideration of the above circumstances, and has an object to provide an ophthalmic apparatus capable of appropriately measuring convergence accommodation. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the ophthalmic device disclosed herein comprises an optotype presentation unit that presents an optotype to the left and right test eyes, and an objective measurement optical system that objectively measures the ocular characteristics of the left and right test eyes, wherein the optotype presentation unit presents the optotype by changing the convergence position where two lines of sight intersect from the positions of the left and right test eyes, with a pinhole placed at a position conjugate with the pupils of the left and right test eyes, and the objective measurement optical system acquires the objective refraction values ​​of the left and right test eyes when the optotype presented at the convergence position by the optotype presentation unit while placing the pinhole is fused. Effect of the Invention

[0007] According to the ophthalmic apparatus of the present disclosure, convergence accommodation can be appropriately measured. [Brief description of the drawings]

[0008] [Figure 1] 1 is an external perspective view showing an ophthalmic apparatus according to a first embodiment. [Diagram 2] 2 is an explanatory diagram showing a schematic configuration example of a left measurement optical system in the ophthalmologic apparatus of the first embodiment; FIG. [Diagram 3] FIG. 2 is an explanatory diagram showing a control block configuration in the ophthalmologic apparatus of the first embodiment. [Figure 4] FIG. 2 is an explanatory diagram showing an example of a left eye target and a right eye target. [Diagram 5] FIG. 2 is an explanatory diagram for explaining the presentation distance to a visual target and the convergence distance to a convergence position where two lines of sight intersect. [Figure 6] 11 is a flowchart showing a process for measuring convergence accommodation in the first embodiment. [Figure 7] 13 is a graph showing the relationship characteristics between the prism angle and the objective refraction value when the average objective refraction value is obtained at each stage of the convergence distance for a plurality of subjects. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of an ophthalmic apparatus according to the present disclosure will be described with reference to FIGS. EXAMPLES

[0010] As shown in FIG. 1, the ophthalmic device 100 is an open-eye type device that can measure the ocular characteristics of both eyes simultaneously while the subject keeps both eyes open. The ophthalmic device 100 can also measure the ocular characteristics of one eye at a time by blocking one eye or turning off the fixation target. The ophthalmic device 100 is also an objective measurement device with a subjective test function that has a target presentation function, a phoropter function, and an autoreflex-keratometer measurement function. Therefore, the examiner can use the ophthalmic device 100 to perform any objective test and subjective test and objectively and subjectively measure the ocular characteristics of the test eye.

[0011] The objective examination that can be performed by the ophthalmic apparatus 100 includes a measurement for acquiring the ocular characteristics of the subject's eye and a photographing for acquiring an image of the subject's eye. The objective examination includes refractive power measurement (refractometry), corneal shape measurement (keratometry), intraocular pressure measurement, fundus photography, tomography (OCT photography) using optical coherence tomography (hereinafter referred to as "OCT: abbreviation for "Optical Coherence Tomography"), and a measurement using OCT. In a subjective examination, a visual target or the like is presented to the subject, and information (ocular characteristics) about the subject's eye is measured based on the subject's response to the presented visual target or the like. The subjective examination includes subjective refraction measurements such as a far-distance examination, an intermediate-distance examination, a near-distance examination, a contrast examination, and a glare examination, and a visual field examination.

[0012] [Overall configuration of the device] The ophthalmologic apparatus 100 includes a support base 110, a measurement unit 120, an examiner's controller 130, and a control unit 140. In this embodiment, the up-down direction (Y-axis direction), the front-back direction (Z-axis direction (directions that are the near side and the far side when viewed from the front of FIG. 1)), and the left-right direction (X-axis direction (left-right direction when viewed from the front of FIG. 1)) perpendicular thereto are used. The upper side in the up-down direction is the positive side in the Y-axis direction, the subject side in the front-back direction (the right front side when viewed from the front of FIG. 1) is the positive side in the Z-axis direction, and the far right side in the left-right direction when viewed from the front of FIG. 1 is the positive side in the X-axis direction.

[0013] 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.

[0014] 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.

[0015] The measurement head 122 measures the ocular characteristics of the subject's eye E (see Figs. 2 and 4). 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. The left measurement head unit 122L and the right measurement head unit 122R correspond to the subject's left and right eyes E, respectively. The drive unit 122a can drive 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, respectively.

[0016] The left measurement head unit 122L incorporates a left measurement optical system 125L. The left measurement optical system 125L presents a visual target 8 (see FIG. 4) to the subject's left eye E (hereinafter also referred to as the left eye EL) and measures the eye characteristics of the left eye EL with the visual target 8 set to an arbitrary spherical power (corrective power). The right measurement head unit 122R incorporates a right measurement optical system 125R. The right measurement optical system 125R presents a visual target 8 to the subject's right eye E (hereinafter also referred to as the right eye ER) and measures the eye characteristics of the right eye ER with the visual target 8 set to an arbitrary spherical power (corrective power). The detailed configurations of the left measurement optical system 125L and the right measurement optical system 125R will be described later in the section "Configuration of the Optical System."

[0017] 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 the forehead during measurement of eye characteristics. That is, the subject presses his / her forehead against the forehead rest 123 while facing the optometry table 112, and stabilizes the face so that the direction and position do not move. 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.

[0018] 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 can be carried separately from the measurement unit 120. 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 apparatus 100. The examiner's controller 130 exchanges information with the control unit 140 via wireless communication or network communication.

[0019] 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 displayed appropriately. 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 the 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 input buttons 132 and the like.

[0020] [Optical system configuration] Next, the detailed configurations of the left measurement optical system 125L and the right measurement optical system 125R will be described with reference to Fig. 2. The left measurement optical system 125L and the right measurement optical system 125R have the same configuration. Therefore, in the following, the left measurement optical system 125L will be used for the description, and the configuration of the right measurement optical system 125R will be omitted.

[0021] The left measurement optical system 125L is an optical system that performs an examination by presenting a visual target 8 (see FIG. 4) to the left test eye EL. 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 and the pupil conjugate position Q are used. 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 an optically conjugate position 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 an optically conjugate position or its vicinity.

[0022] The Z alignment system 1 projects light (infrared light in the first embodiment) for alignment in the optical axis direction (front-back direction) of the anterior eye observation system 5 onto the left test eye EL. The Z alignment system 1 emits light from the Z alignment light source 11, converts the light into a parallel beam by the projection lens 12, and projects the light onto the cornea of ​​the left test eye EL through an alignment hole formed in the keratoplasty plate 31. The control unit 140 or the examiner controls the drive unit 122a based on the bright spot projected onto the cornea so that the ratio between the interval between the two point images by the Z alignment light source 11 on the imaging element 59 of the anterior eye observation system 5 and the diameter of the keratoplasty image falls within a predetermined range, and moves the left measurement optical system 125L in the Z axis direction. As a result, the left measurement optical system 125L is positioned appropriately in the optical axis direction with respect to the left test eye EL.

[0023] The XY alignment system 2 irradiates the left test eye EL with light (infrared light in the first embodiment) 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 has an XY alignment light source 21 and a projection lens 22 on an optical path branched from the anterior eye observation system 5 by a half mirror 54. The XY alignment system 2 causes the light emitted from the XY alignment light source 21 to proceed to the anterior eye observation system 5 through the projection lens 22. The XY alignment system 2 reflects the light by the half mirror 54 and projects it on the left test eye EL through the anterior eye observation system 5. The reflected light by the cornea of ​​the left test eye EL is guided to the image sensor 59 through the anterior eye observation system 5. As a result, the left measurement optical system 125L is appropriately positioned in the X-axis direction and the Y-axis direction with respect to the left test eye EL. The alignment method in each of the X, Y and Z directions is not limited to using the Z alignment system 1 and the XY alignment system 2. For example, a method in which the position of the subject's eye E can be measured by using a stereo camera installed in the ophthalmic apparatus 100 may be used.

[0024] Here, an image (bright spot image) based on the light reflected by the cornea is formed so as to be superimposed on 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 the XY alignment manually, the examiner uses the examiner's controller 130 to move the left measurement optical system 125L in the X-axis direction and the Y-axis direction via the drive unit 122a, and moves the left measurement optical system 125L so as to guide the bright spot image into the alignment mark. When performing the XY alignment automatically, 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.

[0025] The kerato-measurement 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 kerato-measurement system 3 has a kerato-plate 31 disposed between the objective lens 52 of the anterior eye observation system 5 and the left subject eye EL, and a kerato-ring light source 32 provided on the rear side (the objective lens 52 side) of the kerato-plate 31. The kerato-measurement system 3 projects a ring-shaped light beam onto the cornea of ​​the left subject eye EL by illuminating the kerato-plate 31 with light from the kerato-ring light source 32. The reflected light (kerato-ring image) from the cornea of ​​the left subject eye EL can be detected by the imaging element 59 together with the anterior eye image. The control unit 140 calculates a corneal shape parameter representing the shape of the cornea by performing a known calculation based on the kerato-ring image.

[0026] 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, a reflecting mirror 49, and a pinhole plate 50. 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 glare light to the left eye EL at positions surrounding the optical axis on an optical path different from the optical path leading to the display 41 that displays the target 8.

[0027] The display 41 functions as a target presenting unit that presents the target 8, and displays a fixation target or a dot target as a target 8 to which the gaze is fixed 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 value, 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 target 8 to be projected onto the left eye EL and the right eye ER can be arbitrarily created as a still image or a moving image target 8, and the created target 8 can be registered as a selectable chart icon on the chart page. The display 41 can select and display the created still image target 8 or the created moving image target 8 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.

[0028] The visual target projection system 4 reflects light from the display 41 by a half mirror 42, transmits the light through a relay lens 43, reflects the light by a reflecting mirror 44, and transmits the light through a focusing lens 45. The visual target projection system 4 transmits the light through a relay lens 46, aligns the traveling direction of the light by a field lens 47, transmits the light through a VCC 48, reflects the light by a reflecting mirror 49, transmits the light through a dichroic mirror 68, and reflects the light by a dichroic mirror 53. The visual target projection system 4 projects the light reflected by the dichroic mirror 53 onto the fundus ELf through an objective lens 52.

[0029] The focusing lens 45 is driven to advance and retreat 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 approaching the left eye EL, the spherical power of the left 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 eye EL, the spherical power of the left 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 presentation distance Lp from the left eye EL to the optotype presenting position. Here, the focusing lens 45 is configured to move in conjunction with 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.

[0030] 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 presentation distance Lp and the spherical power of the left test eye EL. Then, the control unit 140 displays a predetermined optotype 8 selected by the examiner or the like on the display 41. As a result, the predetermined optotype 8 is presented to the subject at a predetermined presentation distance Lp to the left test eye EL adjusted to a predetermined spherical power. Also, when the subject gives a subjective answer to the optotype 8, the control unit 140 receives an input of the answer. For example, in the case of visual acuity measurement, the examiner selects and presents the next optotype 8 based on the subject's subjective answer to the Landolt ring or the like, and the control unit 140 determines the visual acuity value by repeating this process. For this reason, the optotype projection system 4 functions as a subjective test system.

[0031] The pinhole plate 50 is provided at the pupil conjugate position Q in the target projection system 4, and is provided between the field lens 47 and the VCC 48 in the first embodiment. The pinhole plate 50 is formed by providing a through hole in a plate member. The pinhole plate 50 can be inserted into and removed from the optical path of the target projection system 4 under the control of the control unit 140, and when inserted into the optical path, the through hole is positioned on the optical axis. The pinhole plate 50 is inserted into the optical path in the subjective test mode, thereby making it possible to perform a pinhole test to determine whether or not the left test eye EL can be corrected by glasses. The pinhole plate 50 is also inserted when measuring convergence accommodation, which will be described later. The pinhole plate 50 may be provided at a position on the optical path that is approximately conjugate with the pupil of the left test eye EL, and is not limited to the configuration of the first embodiment.

[0032] The anterior eye observation system 5 observes and photographs the anterior eye of the left eye EL. The anterior eye observation system 5 irradiates the anterior eye of the left eye EL with illumination light (infrared light in the first embodiment) by the anterior eye illumination light source 51. The anterior eye observation system 5 transmits the light reflected by the anterior eye of the left eye EL through the objective lens 52, the dichroic mirror 53 and the half mirror 54, the relay lens 55 and the relay lens 56, and the dichroic mirror 57. The anterior eye observation system 5 forms an image of the light on the imaging surface of the image sensor 59 by the imaging lens 58. The imaging surface of the image sensor 59 is set to the pupil conjugate position Q. The image sensor 59 performs imaging and signal output at a predetermined rate, and outputs the video signal to the control unit 140. The control unit 140 displays an anterior eye image (moving image) based on a video signal that is an output of the imaging element 59 on the display unit 131 of the examiner's controller .

[0033] 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) that measures 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 also 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.

[0034] In the first embodiment, the reflex measurement light source 61 is 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 is movable 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 is a light-transmitting part formed in a ring shape, and is arranged at the pupil conjugate position Q. The focusing lens 74 is movable 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.

[0035] The reflex measurement projection system 6 causes the light emitted from the reflex measurement light source 61 to pass through a relay lens 62 and to be incident on the conical surface of a conical prism 63. The reflex measurement projection system 6 deflects the light incident on the conical surface, causes it to exit from the bottom surface of the conical prism 63, passes through a field lens 64, and passes through a ring diaphragm 65 (its light-transmitting portion). The reflex measurement projection system 6 reflects the light (ring-shaped light beam) on the reflecting surface of a hole prism 66, passes through a rotary prism 67, and is reflected by a dichroic mirror 68. The reflex measurement projection system 6 reflects the reflected light on a dichroic mirror 53, passes through an objective lens 52, and projects it onto the left test eye EL.

[0036] Here, it is desirable that the conical prism 63 is disposed in a position 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.

[0037] Also, 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. Also, 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.

[0038] The reflex measurement light-receiving system 7 passes the return light of the ring-shaped light beam projected onto the fundus ELf through the objective lens 52 and reflects it at the dichroic mirror 53 and the dichroic mirror 68. The reflex measurement light-receiving system 7 passes the reflected return light through the rotary prism 67, the hole of the aperture prism 66, and the relay lens 71, reflects it at the reflecting mirror 72, and passes it through the relay lens 73 and the focusing lens 74. The reflex measurement light-receiving system 7 reflects the transmitted light at the reflecting mirror 75 and the dichroic mirror 57, and forms an image on the imaging surface of the imaging element 59 by the imaging lens 58.

[0039] 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 and 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.

[0040] [Control Unit Configuration] Next, the configuration of the control unit 140 will be described with reference to Fig. 3. The control unit 140 includes a main control unit 141, a storage unit 142, and a convergence adjustment measurement unit 143, as shown in Fig. 3.

[0041] 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 also controls the on / off of the visual target 8 displayed on the display 41 of the visual target projection system 4, and controls the switching of the visual target 8. The main control unit 141 also controls the switching of the pinhole plate 50 of the visual target projection system 4 between insertion into the optical path and removal from there. The main control unit 141 also 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 also controls the change in exposure time and the change in detection sensitivity of the image sensor 59 of the anterior eye observation system 5. The main control unit 141 also 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 of the 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 controls the change of the position of the relay lens 56 of the anterior eye observation system 5 in the optical axis direction. 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 performs the process of writing data to the memory unit 142 and the process of reading data from the memory unit 142.

[0042] The storage unit 142 stores various data. The stored data includes 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 subject's eye information 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 of the left and right subject's eyes EL and ER is performed. The measurement information obtained by the objective measurement optical systems 6 and 7 is stored in the storage unit 142 when refractometry of the left and right subject's eyes EL and ER is performed. 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 apparatus 100.

[0043] The convergence accommodation measurement unit 143 measures the convergence accommodation during stereoscopic vision by the left and right test eyes EL and ER (see FIG. 6). The convergence accommodation measurement unit 143 includes a convergence position setting unit 144, an objective measurement unit 145, and a calculation unit 146.

[0044] The convergence position setting unit 144 presents the left eye target 8L and the right eye target 8R (see FIG. 4) at a target position at a certain presentation distance Lp (for example, infinity) from the left and right test eyes EL and ER with the focal depth of the left and right test eyes EL and ER. Here, the ophthalmologic apparatus 100 has a left measurement head unit 122L incorporating a left measurement optical system 125L corresponding to the left test eye EL, and a right measurement head unit 122R incorporating a right measurement optical system 125R corresponding to the right test eye ER (see FIG. 1). The left eye target 8L and the right eye target 8R are set on the display 41 (target presenting unit) of the target projection system 4 of each of the left measurement optical system 125L and the right measurement optical system 125R. Therefore, the convergence position setting unit 144 projects the left eye target 8L onto the left test eye EL by the left measurement optical system 125L, and projects the right eye target 8R onto the right test eye ER by the right measurement optical system 125R, thereby presenting the left eye target 8L and the right eye target 8R, respectively.

[0045] An example of the left eye target 8L and the right eye target 8R will be described with reference to FIG. 4. In FIG. 4, both targets 8 are arranged side by side, with the left eye target 8L shown on the left side and the right eye target 8R shown on the right side. The left eye target 8L has an asterisk 82 displayed at the center of a rectangular target frame 81 such as a liquid crystal frame, as shown on the left side of FIG. 4. The right eye target 8R has an asterisk 82 displayed at the center of a rectangular target frame 81 such as a liquid crystal frame, as shown on the right side of FIG. 4. The left eye target 8L and the right eye target 8R have asterisks 82 with the same pattern, size, and line width at the center of the target frame 81. The pattern, size, and line width of the 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 when viewed with both eyes are combined into one and viewed as a single image.

[0046] The size and radial line width of the asterisk 82 may be appropriately set. Also, the left eye target 8L and the right eye target 8R may be changed to a different design instead of the asterisk 82.

[0047] Thereby, the convergence position setting unit 144 can fuse the left eye target 8L and the right eye target 8R by making them see a single image. The convergence position setting unit 144 prescribes a state in which the convergence distance Lc changes by controlling the prism angles from the left and right test eyes EL and ER toward the left eye target 8L and the right eye target 8R. The relationship between the presentation distance Lp and the convergence distance Lc will be described with reference to FIG. 5.

[0048] The presentation distance Lp refers to the distance along the Z-axis direction from the left and right test eyes EL, ER to the position where the optotype 8 is presented. In the example shown in FIG. 5, the optotype 8 is presented at a convergence position R2 described later. This presentation distance Lp is set by adjusting the optical distance to the display 41 in the optotype projection system 4 (mainly the position of the focusing lens 45 in the first embodiment). In addition, the presentation distance Lp can be said to be a focusing distance when the left and right test eyes EL, ER are focused on the optotype 8. Here, the presentation distance Lp is the distance from the straight line connecting the left and right test eyes EL, ER to the optotype 8, but is not limited thereto, and may be the distance from each of the test eyes EL, ER to the optotype 8.

[0049] The convergence distance Lc is the distance along the Z axis from the positions of the left and right test eyes EL and ER to the convergence position where the two lines of sight intersect. In the example shown in FIG. 5, for the convergence position R1, the distance along the Z axis from the positions of the left and right test eyes EL and ER to the position where the two lines of sight SL1 and SR1 intersect is the convergence distance Lc1. For the convergence position R2, the distance along the Z axis from the positions of the left and right test eyes EL and ER to the position where the two lines of sight SL2 and SR2 intersect is the convergence distance Lc2. Note that the convergence distance Lc is the distance from the straight line connecting the left and right test eyes EL and ER to the convergence position R where the two lines of sight intersect here, but is not limited thereto, and may be the distance from each of the test eyes EL and ER to the convergence position R where the two lines of sight intersect.

[0050] Here, assume that the convergence distance Lc is changed from the convergence distance Lc2 to the convergence distance Lc1 as shown by the arrow A in Fig. 5. At this time, the convergence angle changes from the convergence angle θ2 at which the lines of sight SL2 and SR2 intersect to the convergence angle θ1 (>θ2) at which the lines of sight SL1 and SR1 intersect with each other as the convergence angle changes from the convergence angle θ2 to the convergence angle θ1. Therefore, the left and right test eyes EL and ER generate eyeball movement in a direction in which the left and right test eyes EL and 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.

[0051] Here, the convergence position setting unit 144 presents the left eye target 8L and the right eye target 8R in both the target projection systems 4 of the left measurement head unit 122L and the right measurement head unit 122R with the pinhole plate 50 inserted at the pupil conjugate position Q on the optical path. Then, in both target projection systems 4, the focal depth of the left and right test eyes EL, ER is deepened, so that the left and right test eyes EL, ER can be made to be in a state where they are clearly visible to a certain extent with respect to the corresponding left eye target 8L and right eye target 8R without adjustment according to the presentation distance Lp. Therefore, even if the convergence distance Lc2 is changed to the convergence distance Lc1, the accommodation function due to the change in the presentation distance Lp does not work for the left and right test eyes EL, ER, and in principle, the objective refraction value should not change even if the left and right test eyes EL, ER are objectively measured. However, when the accommodation function that changes the curvature of the crystalline lens in response to the convergence stimulus actually works, the objective refraction value changes when the left and right test eyes EL, ER are objectively measured. Therefore, the convergence accommodation measurement unit 143 can fuse the left eye target 8L and the right eye target 8R with the pinhole plate 50 inserted, thereby providing only the convergence stimulus to the left and right test eyes EL, ER.

[0052] The convergence position setting unit 144 prescribes a state in which the convergence distance Lc 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 to change the line of sight angle from the left and right test eyes EL, ER toward the left eye target 8L and the right eye target 8R. The convergence position setting unit 144 performs control (rotation angle control) to change the line of sight angle by rotating the left measurement head unit 122L and the right measurement head unit 122R in opposite directions around two rotation axes extending in the Y-axis direction through the left and right test eyes EL, ER. The rotation angle control is performed by the driving unit 122a based on a command from the convergence position setting unit 144.

[0053] Here, 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 8 is changed. For this reason, 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 passing 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 Lc approaches the test eye (rotates the eye inward) is positive, and the prism power in the direction in which the convergence distance Lc moves away from the test eye (rotates the eye outward) is negative. The convergence position setting unit 144 creates a state in which the convergence distance Lc changes stepwise in a distance range from a far position to a close position by controlling the prism angle from the left and right test eyes EL, ER toward the left eye target 8L and the right eye target 8R in a stepwise manner.

[0054] The objective measurement unit 145 is executed in parallel with the processing in the convergence position setting unit 144. The objective measurement unit 145 measures the eye characteristics of the left and right test eyes EL, ER when the convergence distance Lc is changed by the objective measurement optical systems 6, 7, and obtains the objective refraction value as the objective measurement information. Here, the processing in the convergence position setting unit 144 is a processing for prescribing a state in which the convergence distance Lc changes stepwise, as described above. For this reason, the objective measurement unit 145 may measure 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 Lc, and obtain an 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.

[0055] The calculation unit 146 obtains the convergence accommodation of the left and right test eyes EL, ER based on the objective refraction value (Ref value) acquired by the objective measurement unit 145 for each convergence distance Lc, i.e., for each prism power, set by the convergence position setting unit 144. Here, the convergence position setting unit 144 presents the left eye target 8L and the right eye target 8R in a state in which the focal depth of the left and right test eyes EL, ER is deepened by inserting the pinhole plate 50 in both target projection systems 4, thereby providing only the stimulus for convergence accommodation to the test eyes EL, ER. Therefore, the change in the objective refraction value (Ref value) acquired by the objective measurement unit 145 can be regarded as the convergence accommodation for the change in the convergence distance Lc, i.e., the prism power, set by the convergence position setting unit 144. From these, the calculation unit 146 determines the change in the objective refraction value (REF value) relative to the change in the convergence distance Lc or prism dioptric power that is changed stepwise as the convergence accommodation.

[0056] [Configuration and operation flow of the process for measuring convergence accommodation] Next, the configuration and operation flow of the process of measuring convergence accommodation executed by the convergence accommodation measurement unit 143 will be described with reference to the flowchart shown in Fig. 6. This measurement process is started when a mode for measuring convergence accommodation is selected in the ophthalmologic apparatus 100.

[0057] In step S1, a preliminary measurement is performed, and the process proceeds to step S2. In this step S1, the main controller 141 acquires eye characteristics including the refractive values ​​of the left and right test eyes EL and ER as a preliminary measurement 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 condition converges each time the measurement is repeated, or different types of measurement conditions may be determined. 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.

[0058] In step S2, the main measurement is performed, and the process proceeds to step S3. In this step S2, the main controller 141 measures the objective refraction values ​​of the left and right test eyes EL, ER as the main measurement 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. First, 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.

[0059] In step S3, the subjective test start setting is performed, and the process proceeds to step S4. In this step S3, the main controller 141 performs the subjective test start setting for each of the left and right test eyes EL, ER. In this subjective test start setting, the position of the focusing lens 45 in the optotype projection system 4 is adjusted so that the spherical powers of the left and right test eyes EL, ER are in a perfect correction state at the presentation distance Lp position for far vision, based on the refractive values ​​of the left and right test eyes EL, ER obtained in the main measurement (step S2) or the test results in the RG test (step S4).

[0060] In step S4, an RG test is performed to determine whether or not the eye is in a perfect correction state. If the result is YES, the process proceeds to step S5. If the result is NO, the process returns to step S3. In step S4, the main controller 141 performs an RG test using an RG chart. If the eye is in a perfect correction state (proper), the process proceeds to step S5 with a YES result. If the result is overcorrection or undercorrection, the process returns to step S3 with a NO result. This RG test uses an RG chart to subjectively check whether the correction state of each of the left and right test eyes EL and ER is in a perfect correction state (proper), that is, whether the eye is overcorrected or undercorrected, using a characteristic of light called chromatic aberration. The RG chart is, for example, a red icon with optotypes 8 consisting of numbers of different sizes and ◎ and ◯ marks of different sizes, and a green icon with optotypes 8 of the same shape as the red icon, arranged side by side. In the RG test, the light with a green wavelength is imaged at a position shifted toward the incident side compared to the light with a red wavelength, because the shorter the wavelength of light is, the greater the power at the refracting surface is, due to the characteristics of the optic medium of the eye. Therefore, when the left and right test eyes EL, ER are undercorrected, the red optotype 8 is more clearly visible, and when the left and right test eyes EL, ER are overcorrected, the green optotype 8 is more clearly visible. Therefore, the subject repeats steps S3 to S4 until the green and red optotypes 8 on the RG chart are evenly visible, changing the position of the focusing lens 45 to adjust the spherical power (correction power) of the left and right test eyes EL, ER. As a result, the left and right test eyes EL, ER are prescribed perfect correction values ​​based on the provisionally determined values ​​in the RG test.

[0061] Therefore, steps S1 to S4 are complete correction prescription steps in which the left and right test eyes EL, ER are in a state where the complete correction values ​​in the subjective test are prescribed. However, the complete correction values ​​of the left and right test eyes EL, ER are not necessarily provisionally determined values ​​in the RG test in the first embodiment, but may be any of values ​​measured separately, prescription values ​​for the current glasses, values ​​determined by a series of subjective eye tests, etc. Also, at this time, a strabismus or cross-eyes test may be performed to correct the eye positions of the test eyes EL, ER.

[0062] In step S5, the focal depth is deepened to present the left eye target 8L and the right eye target 8R, and the process proceeds to step S6. In this step S5, the convergence position setting unit 144 sets an initial prism angle in the target projection system 4 of each of the left measurement optical system 125L and the right measurement optical system 125R with the pinhole plate 50 inserted at the pupil conjugate position Q on the optical path, and presents the left eye target 8L and the right eye target 8R. In step S5, the rotation angle control is performed to set the initial prism angle. At this time, if the presentation distance Lp is close to the convergence distance Lc at the initial prism angle, the focusing lens control is performed to set the presentation distance Lp to an arbitrary position (for example, a position at infinity).

[0063] In step S6, it is confirmed whether or not fusion has occurred, and the process proceeds to step S7. In this step S6, the convergence position setting unit 144 acquires a subjective answer regarding the fusion of the left eye target 8L and the right eye target 8R from the subject. As the subjective answer, for example, an answer is acquired as to whether or not the target 8 is seen as one object due to the fusion of the left eye target 8L and the right eye target 8R. Here, if the target is not seen as one object, it is confirmed whether or not the subject's eye is properly performing the test, and if not, the setting is reset to an appropriate state, and if it is, the test is stopped, or the eye position is corrected so that the target is seen as one object and the test may be continued.

[0064] In step S7, a prism angle change process is performed, and the process proceeds to step S8. In this step S7, the convergence position setting unit 144 drives the driving unit 122a to change the prism angle stepwise from 0Δ or the previous prism angle to the next prism angle while the pinhole plate 50 is inserted. The prism angle is changed in six steps, for example, 0Δ, +1Δ, +2Δ, +4Δ, +6Δ, and +10Δ. For example, when the initial prism angle is 0Δ, the prism angle is changed in six steps from +1Δ → +2Δ → +4Δ → +6Δ → +10Δ. In this example, the test is performed only in the direction approaching the subject's eye E from a predetermined prism angle, that is, in the direction of adjustment. However, in order to see whether there is an influence of strabismus or the like or whether the adjustment changes when convergence is performed in the divergence direction, the test may be performed in the direction moving away from the predetermined prism angle after changing the angle to a predetermined distance. In addition, the manner of change may be set appropriately, and is not limited to the manner in this example.

[0065] In step S8, it is confirmed whether fusion has been achieved, and the process proceeds to step S9. In this step S8, the convergence position setting unit 144 acquires a subjective answer regarding the fusion of the left eye target 8L and the right eye target 8R with respect to the gradual change in the convergence distance Lc from the subject. As the subjective answer, for example, an answer is acquired as to whether the target 8 is seen as one due to the fusion of the left eye target 8L and the right eye target 8R. Therefore, in step S8, when measuring the convergence accommodation of the left and right test eyes EL and ER, it is possible to confirm whether fusion has been achieved subjectively.

[0066] In step S9, it is determined whether the prism angle change process is completed. If the result is YES, the process proceeds to step S13. If the result is NO, the process returns to step S7. In this step S9, it is determined whether the convergence position setting unit 144 has changed the prism angle to the final prism angle (for example, -10Δ). In other words, in step 9, it is determined whether measurements have been performed for all the prism angles set in advance.

[0067] Here, steps S7 and S9 are convergence distance control steps that prescribe a state in which the convergence distance Lc from the positions of the left and right test eyes EL and 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 and ER toward the left eye target 8L and the right eye target 8R. Then, steps S6 and S8 are subjective answer acquisition steps that acquire a subjective answer regarding fusion from the subject when fusion is attempted by the left and right test eyes EL and ER in response to the change in the convergence distance Lc.

[0068] In step S10, a refraction measurement is performed. In this step S10, 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 Lc by the objective measurement optical system, and obtains the objective refraction value as the objective measurement information. In step S11, the refraction value is displayed at a predetermined timing. In this step S11, the objective measurement unit 145 displays a plurality of objective refraction values ​​(refraction values) obtained at the timing when the prism angle changes. In step S12, the refraction values ​​are compared. In this step S12, the objective measurement unit 145 compares a plurality of refraction values ​​obtained at the timing when the prism angle changes, and calculates an average value. These steps S10 to S12 are executed in parallel with the control of the convergence distance Lc, and when fusion is attempted by the left and right test eyes EL, ER with respect to the change in the convergence distance Lc, the ocular characteristics of the left and right test eyes EL, ER are measured by the objective measurement optical system, and obtains the objective refraction value as the objective measurement information.

[0069] Step S13 calculates the convergence accommodation and ends the measurement process of the convergence accommodation. In this step S13, the calculation unit 146 calculates the convergence accommodation (its value) based on the convergence distance Lc, i.e., the prism power, changed by the convergence position setting unit 144 and the objective refraction value (average refraction value) from the objective measurement unit 145. Specifically, the convergence accommodation is the difference between the refraction value calculated from the presentation distance Lp (infinity in the first embodiment) and the objective refraction value when the convergence distance Lc is changed. The convergence accommodation can be calculated, for example, as a difference using the objective refraction value of one or more prism angles (convergence distance Lc) measured. The convergence accommodation may be displayed as a value calculated for each prism angle (convergence distance Lc), or may be displayed as a graph showing the relationship with each prism angle.

[0070] Next, the flow of the action of the above-mentioned convergence accommodation measurement process (each step) will be described. The measurement process starts when the subject sets his / her face in a predetermined position facing the ophthalmic device 100, and the alignment is completed to properly adjust the positional relationship between the left and right subject's eyes EL and ER and the device, and proceeds to steps S1 → S2 → S3 → S4. For this reason, after starting, the main control unit 141 sets the start of the preliminary measurement, the main measurement, and the subjective test, and then the complete correction value is prescribed based on the provisionally determined value in the RG test using the RG chart. After that, the measurement process proceeds to steps S5 → S6, and the convergence position setting unit 144 sets the initial prism angle with the pinhole plate 50 inserted, and obtains the subject's subjective answer as to whether the images are fused.

[0071] Thereafter, the measurement process proceeds from step S7 to S8 to S9, and the convergence position setting unit 144 switches the prism angle from the initial prism angle (e.g., 0Δ) to the set prism angle, thereby gradually changing the convergence distance Lc to correspond to each prism angle. At this time, when the prism angle (convergence distance Lc) is changed, a subjective answer as to whether or not the image is fused is obtained from the subject. This is repeated until the prism angle is changed to the final prism angle (e.g., -10Δ). Then, in parallel with the change in the prism angle (convergence distance Lc), the flow of proceeding from step S10 to S11 to S12 is repeated, and an objective measurement is performed by the objective measurement unit 145 to obtain an objective refraction value (REF value) when the prism angle (convergence distance Lc) is changed.

[0072] Then, when all the set prism angles (convergence distances Lc) have been changed, the process proceeds from step S9 to S13, and the calculation unit 146 calculates the convergence accommodation (its value) of the left and right test eyes EL, ER based on the prism angles (convergence distances Lc) changed by the convergence position setting unit 144 and the objective refraction value (average refraction value) from the objective measurement unit 145. In this way, the flow of the measurement process of the convergence accommodation is such that the convergence distance control process and the objective measurement are performed in parallel, and when the convergence distance control process is completed, the flow merges with the objective measurement in step S13.

[0073] Here, the objective measurement unit 145 measures the objective refraction value (average refraction value) for each convergence distance Lc (prism angle). Therefore, the calculation unit 146 can calculate the convergence accommodation based on the objective refraction value (average refraction value) for each convergence distance Lc (prism angle), and can obtain the convergence accommodation for each change in the convergence distance Lc (prism angle). [Convergence accommodation calculation function]

[0074] Next, the convergence accommodation calculation operation will be described with reference to Fig. 7. First, as described above, 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 Lc 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. This allows the objective measurement unit 145 to obtain the objective refraction value for each changed prism angle.

[0075] FIG. 7 shows the relationship between the prism angle and the objective refraction value when the average objective refraction value is obtained at each stage of the convergence distance Lc for a plurality of 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). This horizontal axis may be converted to the convergence angle (MA), which is expressed as the reciprocal of the diopter (D) or the convergence distance Lc.

[0076] In Fig. 7, the relational characteristics of the multiple subjects can be divided into a first group G1 and a second group G2. The first group G1 shows a characteristic in which the objective refraction value tends to increase in response to the change in the prism angle from 0Δ→+1Δ→+2Δ→+4Δ→+6Δ→+10Δ. Specifically, the objective refraction value of the first group G1 increases to about D=3.0 as the prism angle changes from +2Δ→+4Δ→+6Δ→+10Δ.

[0077] For this reason, it is estimated that subjects belonging to the first group G1 have a large accommodative response in the left and right test eyes EL and ER when a convergence stimulus is applied due to a change in the convergence distance Lc. Therefore, it can be determined that subjects belonging to the first group G1 have eyes that are prone to convergence accommodation.

[0078] Moreover, the second group G2 exhibits a characteristic that when the prism angle is switched to six stages from 0Δ→+1Δ→+2Δ→+4Δ→+6Δ→+10Δ, the objective refraction value remains constant without reacting to the switching. Specifically, the second group G2 keeps the objective refraction value small, approximately 1.0 or less (D<1.0), even when the prism angle changes from +2Δ→+4Δ→+6Δ→+10Δ.

[0079] For this reason, it is estimated that the subjects belonging to the second group G2 hardly induce a focus accommodation response in the left and right test eyes EL and ER, even though the convergence stimulus is given by changing the convergence distance Lc. Therefore, it can be determined that the subjects belonging to the second group G2 have eyes in which convergence accommodation is difficult to occur.

[0080] [Effects of ophthalmic devices] The ophthalmologic apparatus 100 according to the first embodiment of the present disclosure can provide the following operational effects. The ophthalmic device 100 includes a display 41 as a target presenting unit that presents a target 8 to the left and right eyes E to be examined, and objective measurement optical systems 6 and 7 that objectively measure the eye characteristics of the left and right eyes E to be examined. The target presenting unit presents the target 8 by changing a convergence position R where two lines of sight intersect from the positions of the left and right eyes E to be examined, with a pinhole plate 50 placed at a position conjugate with the pupils of the left and right eyes E. The objective measurement optical systems 6 and 7 acquire the objective refraction values ​​of the left and right eyes E to be examined when the target 8 presented at the convergence position R by the target presenting unit while placing the pinhole plate 50 is fused. Therefore, the ophthalmic device 100 can present the target 8 (left eye target 8L, right eye target 8R) with the focal depth of the left and right eyes E deepened while changing the convergence distance, and can acquire the objective refraction value in that state. In this way, the ophthalmic device 100 can obtain the objective refraction value in a state where only the stimulus of convergence accommodation is given to the subject's eyes EL and ER, and can measure the convergence accommodation. In addition, the ophthalmic device 100 can appropriately determine whether or not the subject's eyes are prone to convergence accommodation.

[0081] In the ophthalmic apparatus 100, the display 41 as a target presenting unit is provided in the target projection system 4 that projects a target to the left and right eyes E. Therefore, the ophthalmic apparatus 100 can present the target 8 with a deep focal depth to the left and right eyes E with a simple configuration by simply inserting the pinhole plate 50 at the pupil conjugate position Q on the optical path of the target projection system 4.

[0082] Further, the ophthalmic device 100 includes a left measurement head unit 122L incorporating a left target projection system (target projection system 4) and a left objective measurement optical system (objective measurement optical systems 6, 7) that are provided on the same optical axis corresponding to the left test eye EL. The ophthalmic device 100 also includes a right measurement head unit 122R incorporating a right target projection system (target projection system 4) and a right objective measurement optical system (objective measurement optical systems 6, 7) that are provided on the same optical axis corresponding to the right test eye ER. The target presenting unit changes the convergence position R at which the target 8 is presented by rotating the left measurement head unit 122L and the right measurement head unit 122R at an equal angle in opposite directions with the pinhole plate 50 disposed in the left target projection system and the right target projection system. Therefore, the ophthalmic device 100 can present the target 8 in a state where the focal depth of the left and right test eyes E is deepened while changing the convergence position R with a simple configuration. In addition, the ophthalmic device 100 can simultaneously perform parallel processing of presenting the visual target 8 by changing the convergence position R with the focal depth of the left and right test eyes E deepened and obtaining the objective refraction values ​​of the left and right test eyes E, so that the convergence accommodation can be measured more easily. Furthermore, when the ophthalmic device 100 changes the convergence position R 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 a state where it is aligned with the optical axis in the left measurement optical system 125L and the right measurement optical system 125R. Therefore, by aligning the visual axis with the optical axis, the ophthalmic device 100 can measure the eye position and gaze direction to confirm whether or not the left and right test eyes EL, ER are objectively able to see from the anterior eye image.

[0083] The ophthalmologic apparatus 100 acquires the objective refraction value of the corresponding left and right test eyes EL and ER each time the left objective measurement optical system (objective measurement optical systems 6, 7) and the right objective measurement optical system (objective measurement optical systems 6, 7) rotate the left measurement head unit 122L and the right measurement head unit 122R. Therefore, the ophthalmologic apparatus 100 can easily acquire the objective refraction value of the left and right test eyes E in a state where the visual target 8 is presented by deepening the focal depth while changing the convergence position R with a simple configuration, that is, in a state where only the convergence stimulus is applied.

[0084] The ophthalmic device 100 includes a control unit 140 that controls the visual target projection system 4 and the objective measurement optical systems 6 and 7, and the control unit 140 determines convergence accommodation based on a change in the objective refraction value with respect to a change in the convergence position R. Therefore, the ophthalmic device 100 can determine convergence accommodation with respect to various changes in the objective refraction value.

[0085] In addition, the ophthalmic device 100 of the first embodiment performs a complete correction prescription step (steps S1 to S4) before presenting the optotype 8 in a state where the focal depth of the left and right eyes E to be examined is deepened while changing the convergence distance Lc. Therefore, the ophthalmic device 100 presents the optotype 8 in a state where the focal depth of the left and right eyes E to be examined is deepened while changing the convergence distance Lc based on a state where the complete correction value is prescribed and the optotype 8 is clearly seen, so that it is possible to more smoothly and appropriately proceed to measurement for convergence accommodation.

[0086] Therefore, the ophthalmic apparatus 100 according to the embodiment of the present disclosure can appropriately measure convergence accommodation.

[0087] The above describes the ophthalmic device of the present disclosure based on Example 1. However, the specific configuration is not limited to Example 1, and design changes and additions are permitted as long as they do not deviate from the gist of the invention according to each claim in the scope of the claims.

[0088] The ophthalmic device 100 of the first embodiment is an example of an objective measurement device with a subjective test function using an internal target, which is equipped with a target presenting function, a phoropter function, and an autorefraction and keratoconstriction measurement function. However, the ophthalmic device is not limited to the device configuration example of the first embodiment. The ophthalmic device may be configured, for example, as a composite device including a target projection device that presents a real target through a pinhole and prescribes a state in which the convergence distance changes, and a device having a phoropter function and an autorefraction measurement function.

[0089] Further, the ophthalmic device 100 of the first embodiment shows an example in which the control of changing the line of sight angle (prism angle) is performed by controlling the left measurement head unit 122L and the right measurement head unit 122R to rotate in opposite directions. The ophthalmic device is not limited to the example of the line of sight angle control of the first embodiment. For example, the ophthalmic device may be a device that performs control of changing the line of sight angle (prism angle) by inserting a prism lens at a position on the optical axis from the left and right test eyes of the visual target projection system to the visual target presenting unit. In addition, the visual target presenting unit may be, for example, a real visual target provided in front of the subject or a display panel, instead of being provided in the visual target projection system, as long as it presents the visual target 8 to the subject eye E. Even in this case, the convergence accommodation can be measured in the same manner as described above by inserting a prism lens at a position on the optical axis from the left and right test eyes to the visual target presenting unit to change the line of sight angle (prism angle). The target presenting unit may use a 3D display or the like, and may measure convergence accommodation in the same manner as above by showing a stereoscopic image in which the convergence distance is changed while keeping the presentation distance constant.

[0090] Furthermore, the ophthalmologic apparatus 100 of the first embodiment may be configured to automatically perform alignment if alignment is misaligned while the objective refraction value is being measured by the objective measurement optical systems 6 and 7. This can be achieved by having the anterior-segment observation system 5 continuously acquire anterior-segment images while the control unit 140 is causing the objective measurement optical systems 6 and 7 to perform measurement, and performing alignment as described above when it is determined that the bright point image has shifted from the center of the alignment mark or that the ratio between the interval between the two point images and the diameter of the keratin ring image is outside a predetermined range.

[0091] In addition, the ophthalmic device 100 of the first embodiment obtains the convergence accommodation using the objective refraction value for each changed prism angle as described above. However, the ophthalmic device 100 may obtain the objective refraction value in a time series (continuously) and obtain the convergence accommodation from the moment when the convergence position R changes and the change thereafter. In that case, the convergence accommodation can be classified into a case where accommodation continues due to the convergence, a case where accommodation is momentarily entered but returns, and a case where accommodation does not move (does not enter) at all.

[0092] In addition, the ophthalmic device 100 of the first embodiment obtains convergence accommodation using the objective refraction value for each changed prism angle as described above. However, the ophthalmic device 100 may also measure whether or not convergence causes miosis, which is one of the near vision responses. This can be measured by having the anterior eye observation system 5 continuously acquire anterior eye images while the objective measurement optical systems 6 and 7 are performing measurement, and judging the size of the pupil in the anterior eye images. The judgment of the pupil size may be performed by the control unit 140 performing image analysis of the anterior eye images, or by the examiner viewing the anterior eye images displayed on the display unit 131. [Explanation of symbols]

[0093] 100 Ophthalmic device 4 Optotype projection system 8 Optotype 41 Display (as an example of an optotype presentation unit) 6, 7 Objective measurement optical system 50 Pinhole plate (as an example of a pinhole) 122L Left measurement head unit 122R Right measurement head unit 140 Control unit E Subject's eye R Convergence position

Claims

1. an optotype presenting unit that presents optotypes to the left and right eyes to be examined; an objective measurement optical system for objectively measuring ocular characteristics of the left and right eyes to be examined, the optotype presenting unit presents the optotype by changing a convergence position where two lines of sight intersect from the positions of the left and right eyes to the subject in a state where a pinhole is disposed at a position conjugate with the pupils of the left and right eyes to be examined, The objective measurement optical system is characterized in that it acquires the objective refraction values ​​of the left and right test eyes when the target presented at the convergence position by the target presenting unit while positioning the pinhole is fused.

2. 2. The ophthalmologic apparatus according to claim 1, wherein the optotype presenting unit is provided in an optotype projection system that projects optotypes onto the left and right eyes to be examined.

3. The left measurement head unit further includes a left target projection system and a left objective measurement optical system that are provided on the same optical axis in correspondence with the left eye to be examined, and a right measurement head unit includes a right target projection system and a right objective measurement optical system that are provided on the same optical axis in correspondence with the right eye to be examined, The ophthalmologic apparatus according to claim 2, characterized in that the visual target presenting unit changes the convergence position at which the visual target is presented by rotating the left measurement head unit and the right measurement head unit at an equal angle in opposite directions with the pinholes positioned in the left visual target projection system and the right visual target projection system.

4. The ophthalmic device according to claim 3, wherein the left objective measurement optical system and the right objective measurement optical system acquire the objective refraction values ​​of the corresponding left and right test eyes each time the left measurement head unit and the right measurement head unit are rotated.

5. Further, a control unit is provided for controlling the visual target projection system and the objective measurement optical system, The ophthalmic apparatus according to claim 2 , wherein the control unit determines convergence accommodation based on a change in the objective refraction value in response to a change in the convergence position.

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