Ophthalmic device

Abstract

The invention provides an ophthalmic apparatus which can easily detect eye position deviation when brightness difference of a visual target presented to a left eye and a right eye is enlarged from a double-eye visual state. An ophthalmic apparatus (1) is provided with a visual target presentation means (visual target projection system (44)) for presenting a left-eye visual target (OtL) to a left subject eye (EL) and presenting a right-eye visual target (OtR) to a right subject eye (ER), and the left-eye visual target (OtL) and the right-eye visual target (OtR) are in the same form. A sighting target presentation means (sighting target projection system (44)) presents a left-eye sighting target (OtL) to a left subject eye (EL) and presents a right-eye sighting target (OtR) to a right subject eye (ER), thereby enlarging the brightness difference between a common portion of the left-eye sighting target (OtL) and the right-eye sighting target (OtR) and maintaining the brightness difference between the remaining portions of the left-eye sighting target (OtL) and the right-eye sighting target (OtR).

Description

Technical Field

[0001] The present disclosure relates to an ophthalmic device. Background Art

[0002] Conventionally, an ophthalmologic apparatus is known that estimates the fatigue level of a subject's eye based on the timing of the breakdown of fusion when the visual field of one subject's eye gradually darkens while the subject is visually recognizing an optotype (see, for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-169601 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, conventional ophthalmic devices detect the eye position deviation (deviated line of sight) of one of the examined eyes, thereby determining the timing of fusional disruption. Therefore, conventional ophthalmic devices cannot detect eye position deviation and therefore cannot determine the timing of fusional disruption, making it impossible to appropriately estimate the degree of fatigue in the examined eye.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an ophthalmologic apparatus capable of easily detecting eye position deviation when the brightness difference of the visual targets presented to the left and right eyes under examination is increased from a binocular vision state.

[0009] Means used to solve problems

[0010] In order to solve the above-mentioned problems, the ophthalmic device disclosed in the present invention is characterized in that it has an optotype presentation mechanism for presenting a left-eye optotype to the left eye under examination and a right-eye optotype to the right eye under examination, wherein the left-eye optotype and the right-eye optotype are of the same form, and the optotype presentation mechanism presents the left-eye optotype to the left eye under examination and the right-eye optotype to the right eye under examination, thereby enlarging the brightness difference between a common part of the left-eye optotype and the right-eye optotype and maintaining the brightness difference between the remaining part of the left-eye optotype and the right-eye optotype.

[0011] Effects of the Invention

[0012] According to the ophthalmologic apparatus of the present disclosure, it is possible to easily detect eye position deviation caused by increasing the brightness difference of the optotypes presented to the left and right eyes to be examined from a binocular vision state. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a perspective view showing the appearance of the ophthalmologic apparatus according to Example 1.

[0014] Figure 2 This is an explanatory diagram schematically showing a driving mechanism of the measuring head of the ophthalmologic apparatus according to Example 1.

[0015] Figure 3 It is an explanatory diagram showing the convergence angle and the sight mark presentation distance.

[0016] Figure 4 This is an explanatory diagram showing the configuration of the left measurement optical system of the ophthalmologic apparatus according to Example 1.

[0017] Figure 5 This is an explanatory diagram showing the left-eye optotype and the right-eye optotype of Example 1.

[0018] Figure 6 It shows Figure 5 An explanatory diagram showing the state after the first visual mark is fused.

[0019] Figure 7 It shows Figure 5 An explanatory diagram showing the state after the second visual marker is fused.

[0020] Figure 8 This is a flowchart showing the flow of the eye fatigue estimation process performed by the control unit of the first embodiment.

[0021] Figure 9 This is an explanatory diagram schematically showing the right eye and the left eye to be examined as viewed from the front, and showing corresponding right eye optotypes and left eye optotypes below each eye to be examined.

[0022] Figure 10 It is shown in Figure 9 FIG. 5 is an explanatory diagram showing a case where the brightness of the first optotype mark of the left eye optotype is reduced and the visual line of the left eye to be examined deviates from the first optotype mark and moves toward the second optotype mark.

[0023] Figure 11 It shows that Figure 10 An explanatory diagram of a case where the line of sight of the left eye to be examined is directed toward the second visual mark, and the line of sight of the right eye to be examined is deviated from the first visual mark and directed toward the second visual mark.

[0024] Figure 12 It is an explanatory diagram showing another example of the left-eye optotype and the right-eye optotype.

[0025] Description of Reference Numerals

[0026] 1: ophthalmic device, 23: driving mechanism (as an example of a convergence adjustment mechanism), 31: display unit, 40: control unit, 44: sight mark projection system (as an example of a sight mark presentation mechanism), 44a: display (as an example of a left-eye display and a right-eye display), 45: anterior ocular observation system (as an example of an eye information acquisition unit), 46: refraction measurement projection system (as an example of an eye information acquisition unit), 47: refraction measurement light receiving system (as an example of an eye information acquisition unit), EL: left eye under examination, ER: right eye under examination, Is: visual line intersection point, Lp sight mark presentation distance, OtL: sight mark for left eye, OtR: sight mark for right eye, s1: first sight mark number, s2: second sight mark number, θc: convergence angle. DETAILED DESCRIPTION

[0027] Below, refer to Figures 1 to 12 , describing one embodiment of the ophthalmic device of the present disclosure.

[0028] [Example 1]

[0029] The ophthalmic device 1 of Example 1 is an ophthalmic device that has an optical system for measuring the ocular characteristics of an eye under examination and is capable of measuring the ocular characteristics of the eye under examination both objectively and subjectively. An examiner can use the ophthalmic device 1 to perform any objective or subjective examination. In an objective examination, the ophthalmic device 1 irradiates light onto the eye under examination and measures (acquires) information related to the eye under examination (ocular characteristics) based on the detection results of the return light. This objective examination includes measurements for obtaining the ocular characteristics of the eye under examination and photographing images of the eye under examination. In addition, objective examinations include objective refraction measurement (refractive index measurement), corneal shape measurement (corneal curvature measurement), intraocular pressure measurement, fundus photography, cross-sectional imaging using optical coherence tomography (OCT photography), and measurements using OCT. In addition, in a subjective examination, the ophthalmic device 1 presents an optotype, etc. to the examinee and measures information related to the eye under examination (ocular characteristics) based on the examinee's response to the optotype, etc. The subjective examination includes subjective refraction measurement such as distance vision examination, intermediate vision examination, near vision examination, contrast examination, glare examination, red-green examination, visual field examination, etc.

[0030] like Figure 1 As shown, the ophthalmic apparatus 1 of Example 1 is a binocular-open type ophthalmic apparatus capable of simultaneously measuring the ocular characteristics of both eyes when the subject has both eyes open. Furthermore, the ophthalmic apparatus 1 of Example 1 can also measure the ocular characteristics of each eye by covering a single eye or extinguishing the fixation mark.

[0031] The ophthalmic apparatus 1 includes a support base 10, a measurement unit 20, an examiner controller 30, a control unit 40, and a subject controller (not shown). Hereinafter, as viewed from the subject facing the ophthalmic apparatus 1, the left-right axis (horizontally) is indicated by an arrow X (X-axis), the up-down axis (vertically) is indicated by an arrow Y (Y-axis), and the direction perpendicular to the left-right and up-down directions (the depth direction of the ophthalmic apparatus 1) is indicated by an arrow Z (Z-axis), which serves as the front-back direction (front-back axis).

[0032] The support base 10 includes a support column 11 extending from the ground and an optometry table 12 supported by the support column. The optometry table 12 is used to place devices and tools used for optometry, such as the examiner controller 30, or to support the patient's posture. The optometry table 12 is supported by the support column 11 so that its position (height) in the Y direction can be adjusted.

[0033] The measuring unit 20 includes an arm 21 and a measuring head 22. One end of the arm 21 is supported by the front end of the support 11, and the other end extends from the support 11 toward the proximal side (the subject's side) along the Z direction. The measuring head 22 is mounted on the front end. Thus, the measuring head 22 is suspended from the support 11 via the arm 21 above the optometry table 12. Furthermore, the arm 21 is movable in the Y direction relative to the support 11. Alternatively, the arm 21 can be made movable in the X and Z directions relative to the support 11.

[0034] The measuring head 22 is used to independently measure the ocular characteristics of the subject's left eye E (left eye EL) and right eye E (right eye ER). The measuring head 22 includes a left-eye drive mechanism 23L and a right-eye drive mechanism 23R attached to the distal end of the arm 21, a left measurement unit 24L located below the left-eye drive mechanism 23L, and a right measurement unit 24R located below the right-eye drive mechanism 23R.

[0035] The left and right measuring units 24L and 24R are provided as a pair to independently correspond to the left and right eyes EL and ER of the subject. The left measuring unit 24L incorporates a left measurement optical system 25L for measuring the ocular characteristics of the left eye EL. The right measuring unit 24R incorporates a right measurement optical system 25R for measuring the ocular characteristics of the right eye ER. The measurement results of the left and right measuring units 24L and 24R are output to the control unit 40.

[0036] The left-eye driving mechanism 23L is a mechanism that drives the left measuring section 24L to move horizontally (in the X direction), move vertically (in the Y direction), rotate in the X direction, and rotate in the Y direction. Figure 2As shown, the left-eye drive mechanism 23L includes a left vertical drive unit 26L, a left horizontal drive unit 27L, a left Y-axis rotation drive unit 28L, and a left X-axis rotation drive unit 29L. The right-eye drive mechanism 23R drives the right measuring unit 24R in horizontal (X-direction) movement, vertical (Y-direction) movement, X-direction rotation, and Y-direction rotation. The right-eye drive mechanism 23R includes a right vertical drive unit 26R, a right horizontal drive unit 27R, a right Y-axis rotation drive unit 28R, and a right X-axis rotation drive unit 29R.

[0037] Furthermore, the left-eye drive mechanism 23L and the right-eye drive mechanism 23R are constructed to be plane-symmetrical in the X direction with respect to a vertical plane located midway between them. Hereinafter, unless otherwise specified, the left-eye drive mechanism 23L and the right-eye drive mechanism 23R are referred to as the drive mechanism 23, the left measuring unit 24L and the right measuring unit 24R are referred to as the measuring unit 24, the left vertical drive unit 26L and the right vertical drive unit 26R are referred to as the vertical drive unit 26, the left horizontal drive unit 27L and the right horizontal drive unit 27R are referred to as the horizontal drive unit 27, the left Y-axis rotation drive unit 28L and the right Y-axis rotation drive unit 28R are referred to as the Y-axis rotation drive unit 28, and the left X-axis rotation drive unit 29L and the right X-axis rotation drive unit 29R are referred to as the X-axis rotation drive unit 29.

[0038] The vertical drive unit 26 is provided between the arm 21 and the horizontal drive unit 27 so that the horizontal drive unit 27 moves in the Y direction (vertical direction) relative to the arm 21. The horizontal drive unit 27 is provided between the vertical drive unit 26 and the Y-axis rotary drive unit 28 so that the Y-axis rotary drive unit 28 moves in the X direction and the Z direction (horizontal direction) relative to the vertical drive unit 26. The vertical drive unit 26 and the horizontal drive unit 27 are configured to include an actuator for generating a driving force such as a pulse motor and a transmission mechanism for transmitting the driving force such as a combination of gears or a rack and pinion. In the horizontal drive unit 27, for example, a combination of an actuator and a transmission mechanism is independently provided in the X direction and the Z direction, so that the horizontal drive unit 27 can be easily constructed and the control of the movement in the horizontal direction becomes easy.

[0039] The Y-axis rotation drive unit 28 is provided between the horizontal drive unit 27 and the X-axis rotation drive unit 29, and causes the X-axis rotation drive unit 29 to rotate relative to the horizontal drive unit 27 about the eye rotation Y-axis, which passes through the eye rotation point O of the corresponding examined eye E and extends in the Y direction. The X-axis rotation drive unit 29 is provided between the Y-axis rotation drive unit 28 and the corresponding measurement unit 24, and causes the corresponding measurement unit 24 to rotate relative to the Y-axis rotation drive unit 28 about the eye rotation X-axis, which passes through the eye rotation point O of the corresponding examined eye E and extends in the X direction.

[0040] The Y-axis rotation drive unit 28 and the X-axis rotation drive unit 29 are configured to have an actuator and a transmission mechanism similar to the vertical drive unit 26 or the horizontal drive unit 27, and the transmission mechanism, which receives the driving force from the actuator, moves along the arc-shaped guide groove. By aligning the center position of the guide groove with the eye rotation Y-axis, the Y-axis rotation drive unit 28 can rotate the measurement unit 24 around the eye rotation Y-axis of the corresponding examinee's eye E. In addition, by aligning the center position of the guide groove with the eye rotation X-axis, the X-axis rotation drive unit 29 can rotate the measurement unit 24 around the eye rotation X-axis of the corresponding examinee's eye E. That is, by aligning the center position of each guide groove of the Y-axis rotation drive unit 28 and the X-axis rotation drive unit 29 with the eye rotation point O of the corresponding examinee's eye E, the measurement unit 24 can rotate around the eye rotation point O in the left-right direction (rotation direction centered on the Y direction) and the up-down direction (rotation direction centered on the X direction).

[0041] Alternatively, the Y-axis rotation drive unit 28 may support the measurement unit 24 so as to be rotatable about a Y-axis rotation axis provided therein, and in conjunction with the horizontal drive unit 27, change the position at which the measurement unit 24 is supported and rotate it via the X-axis rotation drive unit 29, thereby causing the measurement unit 24 to rotate about the Y-axis of eye rotation of the corresponding examinee's eye E. Alternatively, the X-axis rotation drive unit 29 may support the measurement unit 24 so as to be rotatable about an X-axis rotation axis provided therein, and in conjunction with the vertical drive unit 26, change the position at which the measurement unit 24 is supported and rotate it, thereby causing the measurement unit 24 to rotate about the X-axis of eye rotation of the corresponding examinee's eye E.

[0042] In this manner, the drive mechanism 23 moves the left measurement unit 24L and the right measurement unit 24R independently or in conjunction with each other in the X, Y, and Z directions, causing the left measurement unit 24L to rotate vertically and horizontally around the gyration point O of the left eye EL, and the right measurement unit 24R to rotate vertically and horizontally around the gyration point O of the right eye ER. Thus, the drive mechanism 23 can move the left measurement unit 24L and the right measurement unit 24R to desired positions (postures) relative to their respective eyes E.

[0043] Furthermore, the drive mechanism 23 can make the left eye EL and the right eye ER diverge (divergence movement) or converge (convergence movement) by adjusting the positions of the left measuring section 24L and the right measuring section 24R. In other words, the drive mechanism 23 (the left eye drive mechanism 23L and the right eye drive mechanism 23R) becomes a convergence adjustment mechanism for adjusting the convergence distance Lc. Figure 3As shown, the convergence distance Lc is the distance along the Z direction from both eyes E to the line of sight intersection point Is when looking down at the left and right eyes E (EL, ER). This line of sight intersection point Is is the point where the line of sight SL (line of sight) of the left eye EL intersects with the line of sight SR (line of sight) of the right eye ER (convergence position). The angle formed by the line of sight SL and SR is called the convergence angle θc. The convergence distance Lc is set by controlling the convergence angle θc.

[0044] In the ophthalmologic apparatus 1 of the first embodiment, the left measurement unit 24L and the right measurement unit 24R are each provided with a deflecting member 24a (see Figure 1 、 Figure 2 ). The left measuring optical system 25L and the right measuring optical system 25R respectively obtain the eye characteristics of the corresponding examinee's eye E through the deflection member 24a. The ophthalmic device 1 adjusts the positions of the left measuring unit 24L and the right measuring unit 24R in such a way that each deflection member 24a is in a position corresponding to the left and right examinee's eye E (EL, ER), respectively, so that the eye characteristics of both eyes can be obtained simultaneously when the examinee has both eyes open (in a binocular vision state). In addition, in the ophthalmic device 1, the rotation posture of the left measuring unit 24L and the right measuring unit 24R is changed around the eyeball rotation X-axis by the X-axis rotation drive unit 29, thereby obtaining the eye characteristics in a state where the examinee's eye E is looking downward or upward. Moreover, in the ophthalmic device 1, the rotation posture of the left measuring unit 24L and the right measuring unit 24R is changed around the eyeball rotation Y-axis by the Y-axis rotation drive unit 28, thereby obtaining the eye characteristics in a state where the examinee's eye E is looking leftward or rightward.

[0045] The examiner controller 30 is an information processing device that receives operations from the examiner and outputs control signals to the control unit 40. The examiner controller 30 is, for example, a tablet computer terminal or a smartphone, and can be detached from the measuring unit 20 and carried by the examiner. Alternatively, the examiner controller 30 may be a notebook personal computer or a desktop personal computer, or a controller dedicated to the ophthalmic apparatus 1. The examiner controller 30 exchanges information with the control unit 40 via wireless communication and network communication.

[0046] In addition, if Figure 1 As shown, the examiner controller 30 includes a display unit 31, an operator-side control unit (not shown), and input buttons. The display unit 31 is composed of a touch panel display provided on the surface of the examiner controller 30, and is configured with input buttons. The operator-side control unit is composed of a microcomputer built into the examiner controller 30. The operator-side control unit controls the image displayed on the display unit 31 based on the measurement and detection results transmitted from the control unit 40. Furthermore, the operator-side control unit outputs control signals corresponding to operations on the input buttons to the control unit 40.

[0047] The control unit 40 is an information processing device installed below the optometry table 12. Based on control signals transmitted from the examiner's controller 30, the control unit 40 centrally controls the various components of the measurement unit 20, including the left and right measurement optical systems 25L and 25R. Furthermore, the control unit 40 transmits the measurement results of the ocular characteristics of the left and right examinee eyes E (EL, ER), measured by the left and right measurement units 24L and 24R, to the examiner's controller 30.

[0048] The control unit 40 of the present disclosure can perform an asthenopia estimation process for estimating asthenopia of the examined eye E. First, in the asthenopia estimation process, the control unit 40 controls the optotype presenting mechanism (the optotype projection system 44 described later) to present an optotype Ot for the left eye OtL and an optotype OtR for the right eye Ot, which are the optotypes described later and are at equal distances Lp from an arbitrary optotype presentation, to the left eye EL and the right eye ER. Figure 5 At this time, the control unit 40 controls the drive mechanism 23 (the left-eye drive mechanism 23L and the right-eye drive mechanism 23R) to adjust the positions (orientations) of the left and right measurement units 24L and 24R, setting the convergence angle θc to a predetermined angle and setting the convergence distance Lc to an arbitrary value. This convergence distance Lc may be different from or the same as the sight mark presentation distance Lp.

[0049] In addition, if Figure 3 As shown, the optotype presentation distance Lp is the distance along the Z direction from the left eye EL to the optotype Ot presented to the left eye EL, and the distance along the Z direction from the right eye ER to the optotype Ot presented to the right eye ER. The optotype presentation distance Lp for the left eye EL and the optotype presentation distance Lp for the right eye ER are set to be the same distance. In addition, in the first embodiment, the optotype presentation distance Lp can be adjusted by the optotype projection system 44 (see Figure 4 The sight mark presentation distance Lp can be calculated based on the power of the sight mark projection system 44 (the power of the lens to deflect light) and expressed as a diopter conversion value.

[0050] Specifically, the control unit 40 uses the position corresponding to the far point that matches the refractive power (spherical equivalent) of the left and right eyes E (EL, ER) as a reference, and moves the focusing lens 44e of the optotype projection system 44 so that the optotype Ot is presented at an arbitrary predetermined distance (optotype presentation distance Lp), thereby controlling the power of the optotype projection system 44. For example, when the optotype presentation distance Lp is set to 50 cm, the control unit 40 moves the focusing lens 44e relative to the position corresponding to the far point of both eyes E (e.g., the refractive power of both eyes E is -5.0 D) so as to achieve myopia (e.g., the refractive power of both eyes E is -5.0 D) by an amount equivalent to the power difference (2.0 D) between the position corresponding to the far point (0 D) and the position 50 cm (2.0 D) when the optotype Ot is presented. The power of the optotype projection system 44 is then changed, so that the optotype Ot is presented at the position with a refractive power of -2.0 D. As a result, the control unit 40 can display the optotype O at a position 50 cm away from both eyes E to be examined via the optotype projection system 44 .

[0051] In addition, when the control unit 40 performs the eye fatigue estimation process, it can also set the convergence distance Lc set by the convergence angle θc to a distance shorter than the sight mark presentation distance Lp. At this time, the control unit 40 maintains the sight mark presentation distance Lp, and sets the visual line intersection point Is of the position (orientation) of the left measuring unit 24L and the right measuring unit 24R to a position closer to the side of the body (shorter distance) than the sight mark presentation distance Lp. That is, during the eye fatigue estimation process, the control unit 40 sets the convergence angle θc1 of the position (orientation) of the left measuring unit 24L and the right measuring unit 24R to a value larger than the convergence angle θc2 when the sight mark Ot is visually presented to both eyes. Thus, it is also possible to make the left eye EL and the right eye ER perform convergence movement in a manner of seeing a distance closer than the sight mark presentation distance Lp, so that the left eye EL and the right eye ER are in a state of rotating inward (refer to Figure 3 ).

[0052] Next, the subject is made to gaze at a common portion of the left eye optotype OtL and the right eye optotype OtR, and the portion is fused. In this state, the control unit 40 gradually increases the difference (brightness difference (contrast difference)) between the brightness of a portion of the left eye optotype OtL (the contrast of the optotype with respect to the background) and the brightness of at least a portion of the right eye optotype OtR (the contrast of the optotype with respect to the background). In the state where the brightness difference has been increased, the control unit 40 generates an image based on the eye information (anterior ocular image E′ (refer to FIG. 4 ) obtained by the eye information acquisition unit (the anterior ocular observation system 45 described later) Figure 4 )) and the rotation angles of the left measuring unit 24L and the right measuring unit 24R, and detects the sight line direction SL of the left eye EL and the sight line direction SR of the right eye ER.

[0053] To detect the gaze directions SL and SR, the control unit 40 first determines the two-dimensional positions of the pupil centers of the left and right eyes EL and ER based on the anterior ocular images E' of the left and right eyes EL and ER, as well as the magnification and the rotation angle of the left and right measuring units 24L and 24R controlled by the drive mechanism 23. Next, the control unit 40 determines the two-dimensional position, i.e., the reference position, of the bright spot (bright spot image Br) drawn by the XY alignment system 42 based on the anterior ocular images E' of the left and right eyes EL and ER, as well as the magnification and the rotation angle of the left and right measuring units 24L and 24R controlled by the drive mechanism 23. The control unit 40 then determines the gaze directions SL and SR based on the reference position and the pupil center position. The method for determining the gaze directions SL and SR is not limited to the method described above; other known methods may also be used. Then, the control unit 40 estimates the degree of fatigue (eye strain) of the left eye EL and the right eye ER based on the line of sight direction SL of the left eye EL and the line of sight SR of the right eye ER.

[0054] Furthermore, when the control unit 40 detects the gaze direction SL of the left eye EL and the gaze direction SR of the right eye ER during the asthenopia estimation process, it detects the focus position (accommodation position) of the left eye EL and the right eye ER, respectively, based on the eye information (annular image generated by fundus reflected light) acquired by the eye information acquisition unit (the refractometry projection system 46 and the refractometry light receiving system 47 described later). The focus position is represented by the refractive power of the left eye EL or the right eye ER when observing at a predetermined position.

[0055] Then, based on Figure 4 The detailed structures of the left and right measuring optical systems 25L and 25R will be described. The left and right measuring optical systems 25L and 25R have the same structure. Therefore, the description of the right measuring optical system 25R will be omitted below, and only the left measuring optical system 25L will be described.

[0056] The left measurement optical system 25L is an optical system that presents an arbitrary visual mark (including the visual mark Ot described later) to the left eye under examination EL and performs an inspection. The left measurement optical system 25L includes a Z alignment system 41, an XY alignment system 42, a corneal curvature measurement system 43, a visual mark projection system 44, an anterior ocular observation system 45, a refraction measurement projection system 46, and a refraction measurement light receiving system 47. In addition, 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 roughly conjugate with the fundus Ef of the left eye under examination EL in a state where alignment is completed, and indicates an optically conjugate position or its vicinity. In addition, the pupil conjugate position Q is a position that is optically roughly conjugate with the pupil of the left eye under examination EL in a state where alignment is completed, and indicates an optically conjugate position or its vicinity.

[0057] The Z alignment system 41 projects alignment light (infrared light in Example 1) in the optical axis direction (front-back direction) of the anterior ocular segment observation system 45 onto the left eye EL. The Z alignment system 41 emits light from the Z alignment light source 41a, converts the light into a parallel beam through the projection lens 41b, passes through the alignment hole formed in the corneal plate 43a, and projects it onto the cornea Ec of the left eye EL. Based on the bright spot projected onto the cornea Ec, the control unit 40 or the examiner moves the left measurement unit 24L (right measurement unit 24R) so that the ratio of the distance between the two point images produced by the Z alignment light source 41a on the imaging element 45h of the anterior ocular segment observation system 45 and the diameter of the corneal annular image falls within a specified range, thereby moving the left measurement optical system 25L in the Z-axis direction. This positions the left measurement optical system 25L appropriately relative to the left eye EL in the optical axis direction.

[0058] The XY alignment system 42 irradiates the left eye EL with light (infrared light in Example 1) for alignment in the X-axis and Y-axis directions that are orthogonal to the optical axis (Z-axis) of the anterior ocular segment observation system 45. The XY alignment system 42 includes an XY alignment light source 42a and a projection lens 42b on an optical path branched from the anterior ocular segment observation system 45 by a half-mirror 45c. The XY alignment system 42 allows the light emitted from the XY alignment light source 42a to pass through the projection lens 42b and advance toward the anterior ocular segment observation system 45. In the XY alignment system 42, the light is reflected by the half-mirror 45c, passes through the anterior ocular segment observation system 45, and is projected onto the left eye EL. The reflected light from the cornea Ec of the left eye EL passes through the anterior ocular segment observation system 45 and is guided to the imaging element 45h. Based on the bright spot projected onto the cornea Ec, the control unit 40 or the examiner moves the left measurement unit 24L (right measurement unit 24R) in the vertical or horizontal directions to perform alignment in directions perpendicular to the optical axis L of the anterior ocular segment observation system 45 (the Y direction, vertical direction, and the X direction, horizontal direction). This positions the left measurement optical system 25L appropriately relative to the left eye EL in the X-axis and Y-axis directions. Furthermore, the alignment method in the X, Y, and Z directions is not limited to using the Z alignment system 41 or the XY alignment system 42. For example, a method using a stereo camera or the like provided in the ophthalmologic apparatus 1 to measure the position of the eye E may also be employed.

[0059] The image of the reflected light from the cornea Ec (bright spot image Br) is formed by overlapping the anterior ocular segment image E'. The control unit 40 controls the display unit 31 to display the anterior ocular segment image E' including the bright spot image Br and the alignment mark. When performing manual XY alignment, the examiner uses the examiner controller 30 to move the left measurement optical system 25L in the X-axis and Y-axis directions, moving it so that the bright spot image is guided within the alignment mark. When performing automatic XY alignment, the control unit 40 moves the left measurement unit 24L (right measurement unit 24R) in a manner that cancels the displacement of the bright spot image relative to the alignment mark, thereby moving the left measurement optical system 25L in the X-axis and Y-axis directions.

[0060] The keratometer 43 projects an annular beam (infrared light) onto the cornea Ec to measure the shape of the cornea Ec of the left eye EL. The keratometer 43 includes a corneal plate 43a positioned between the objective lens 45a of the anterior ocular segment observation system 45 and the left eye EL, and a corneal ring light source 43b located on the back side (on the side of the objective lens 45a) of the corneal plate 43a. The keratometer 43 projects an annular beam onto the cornea Ec of the left eye EL by directing light from the corneal ring light source 43b through the slit in the corneal plate 43a. The reflected light (corneal annular image) from the cornea Ec of the left eye EL can be detected by the imaging element 45h along with the anterior ocular segment image E′. The control unit 40 performs known calculations based on the corneal annular image to calculate corneal Ec shape parameters representing the shape of the cornea Ec.

[0061] The optotype projection system 44 sets the optotype presentation distance Lp to an arbitrary distance and presents various optotypes, such as a fixation target, a subjective test target, or an optotype Ot, to the left eye EL. The optotype projection system 44 includes a display 44a, a half-mirror 44b, a relay lens 44c, a reflector 44d, a focusing lens 44e, a relay lens 44f, a field lens 44g, a variable cross cylinder lens (VCC) 44h, a reflector 44k, and a pinhole plate 44m. The optotype projection system 44 shares a dichroic mirror 46h with the refractometry projection system 46. The optotype projection system 44 shares a dichroic mirror 45b and an objective lens 45a with the anterior ocular observation system 45. Furthermore, the optotype projection system 44 includes at least two glare light sources 44n located around the optical axis, on optical paths separate from the optical paths that reach the display 44a and other devices displaying the various optotypes, for illuminating the left eye EL with glare.

[0062] The display 44a functions as a sight mark presentation unit that presents various sight marks, and is therefore provided at a fundus conjugate position P on the optical path of the sight mark projection system 44. The display 44a displays a fixation mark or a dot sight mark that fixes the line of sight when conducting an objective examination or applying fog to the left eye EL, or a subjective inspection sight mark that subjectively inspects the eye characteristics (visual acuity value, distance vision, near vision, etc.) of the left eye EL. The display 44a can use EL (Electroluminescent Display) or a Liquid Crystal Display (LCD), etc., and can display sight marks in a desired shape, form, and desired contrast (brightness). The display 44a can display any sight mark under the control of the control unit 40, and can arbitrarily change the brightness of the displayed sight mark (the contrast of the sight mark relative to the background). In Example 1, the display 44a displays the sight mark Ot used for eye fatigue estimation processing under the control of the control unit 40 (refer to Figure 5The left-eye optotype OtL (the right-eye optotype OtR in the right measuring optical system 25R, etc.) is used, and the brightness of a part thereof is appropriately changed.

[0063] In the optotype projection system 44, light from the display 44a is reflected by the half mirror 44b, passes through the relay lens 44c, is reflected by the reflector 44d, and passes through the focusing lens 44e. In the optotype projection system 44, this light passes through the relay lens 44f, is aligned in direction by the field lens 44g, passes through the VCC 44h, is reflected by the reflector 44k, passes through the dichroic mirror 46h, and is reflected by the dichroic mirror 45b. In the optotype projection system 44, the light reflected by the dichroic mirror 45b passes through the objective lens 45a and is projected onto the fundus Ef.

[0064] The focusing lens 44e is driven forward and backward in the direction of the optical axis by a driving motor (not shown) controlled by the control unit 40. If the control unit 40 controls the focusing lens 44e to move in a direction close to the left eye EL, the spherical power of the left eye EL changes to the negative diopter side (-D side), that is, the refractive index is negative. In addition, if the control unit 40 controls the focusing lens 44e to move in a direction away from the left eye EL, the spherical power of the left eye EL changes to the positive diopter side (+D side), that is, the refractive index is positive (hyperopia direction). Moreover, by controlling the forward and backward driving of the focusing lens 44e, the control unit 40 can change the presentation position of the sight mark displayed on the display 44a, that is, the sight mark presentation distance Lp from the left eye EL to the sight mark presentation position, to an arbitrary value. Among them, the focusing lens 44 e is configured to move in conjunction with the refraction measurement light source 46 a of the refraction measurement projection system 46 and the focusing lens 47 d of the refraction measurement light receiving system 47 .

[0065] In the case of a subjective examination, the control unit 40 moves the focusing lens 44e in the direction of the optical axis based on the results of the objective measurement, and controls the sight mark presentation distance Lp and the spherical power of the left eye EL to be examined. Then, the control unit 40 displays the prescribed sight mark selected by the examiner or the like on the display 44a. Thus, the prescribed sight mark is presented to the examinee at the prescribed sight mark presentation distance Lp for the left eye EL to be examined, which is adjusted to the prescribed spherical power. In addition, if the examinee makes a subjective answer to the sight mark, the input of the answer content is accepted. For example, in the case of visual acuity measurement, the control unit 40 selects and presents the next sight mark based on the examinee's subjective answer to the Landoltring or the like, and repeats this operation to determine the visual acuity value. Therefore, the sight mark projection system 44 functions as a subjective examination system.

[0066] As can be seen from this, the ophthalmologic apparatus 1 can independently present optotypes (including the left-eye optotype OtL) to the left eye EL and can set the optotype presentation distance Lp to any desired distance. Therefore, the display 44a of the left measurement optical system 25L functions as a left-eye display, presenting the left-eye optotype OtL. The same applies to the right measurement optical system 25R, where the display 44a functions as a right-eye display, presenting the right-eye optotype OtR. Thus, the ophthalmologic apparatus 1 can independently vary the brightness of the optotypes presented to the left eye EL and the right eye ER, either partially or entirely, and appropriately increase the brightness difference between the left and right optotypes.

[0067] In the sight mark projection system 44, the pinhole plate 44m is arranged at the pupil conjugate position Q, and in Example 1, it is arranged between the field lens 44g and the VCC44h. The pinhole plate 44m is formed by providing a through hole on the plate member. The pinhole plate 44m can be inserted into the optical path of the sight mark projection system 44 and detached from the optical path under the control of the control unit 40. If inserted into the optical path, the through hole is located on the optical axis. The pinhole plate 44m is inserted into the optical path in the subjective inspection mode, so that a pinhole test can be performed to determine whether the left eye EL can be corrected by glasses. In addition, the pinhole plate 44m can also be inserted when measuring the convergence adjustment described later. In addition, the pinhole plate 44m only needs to be arranged at a position roughly conjugate with the pupil of the left eye EL on the optical path, and is not limited to the structure of Example 1.

[0068] The anterior segment observation system 45 observes the anterior segment of the left eye EL and acquires an anterior segment image E'. The anterior segment observation system 45 irradiates the anterior segment of the left eye EL with illumination light (infrared light in Example 1) from the anterior segment illumination light source 48. In the anterior segment observation system 45, light reflected by the anterior segment of the left eye EL passes through the objective lens 45a, the dichroic mirror 45b and the half-mirror 45c, the relay lens 45d and the relay lens 45e, and the dichroic mirror 45f. The anterior segment observation system 45 forms an image of this light onto the imaging surface of the imaging element 45h via the imaging lens 45g. The imaging surface of the imaging element 45h is located at the pupil conjugate position Q. As a result, an anterior segment image E' is formed on the imaging element 45h, which is a corneal ring image or a projection of the light beam from the Z alignment light source 41a or the light beam from the XY alignment light source 42a (bright spot image Br). The imaging element 45h captures images and outputs signals at a predetermined ratio, and outputs the resulting image signals to the control unit 40. The control unit 40 displays an anterior ocular segment image E′ (moving image) based on the image signal output from the imaging element 45h on the display unit 31 of the examiner controller 30. Furthermore, the control unit 40 can detect the line of sight SL of the left eye EL to be examined based on the anterior ocular segment image E′ and the rotation angle of the left measurement unit 24L.

[0069] The refractometry projection system 46 and the refractometry light receiving system 47 are objective measurement optical systems used to perform objective refraction measurement (refractometry) to measure the objective refractive value (refractive characteristic) of the left eye under examination (EL). The refractometry projection system 46 projects a ring-shaped beam (infrared light) for objective measurement from a refractometry light source 46a toward the fundus Ef. The refractometry light receiving system 47 receives the return light of this ring-shaped beam from the left eye under examination (EL). The refractometry projection system 46 and the refractometry light receiving system 47 are not limited to the configurations of Example 1, as long as they project a measuring beam toward the fundus Ef of the left eye under examination (EL) and obtain the measuring beam reflected by the fundus Ef as a measuring ring image. Another example of a configuration of the refractometry projection system 46 and the refractometry light receiving system 47 is to project a point light as the measuring beam toward the fundus Ef, and then pass the measuring beam (the reflected beam) reflected by the fundus Ef through an annular slit or lens to form an annular beam, thereby obtaining a measuring ring image.

[0070] In Example 1, the refractometer light source 46a is a high-brightness light source, namely, an SLD (Super Luminescent Diode) light source, whose emission diameter is less than a specified size. The refractometer light source 46a is linked to the focusing lens 44e and the focusing lens 47d, and is movable along the optical axis. It is located at the fundus conjugate position P. The annular aperture 46e is a ring-shaped light-transmitting portion, and is located at the pupil conjugate position Q. The focusing lens 47d is linked to the refractometer light source 46a and the focusing lens 44e, and is movable along the optical axis. This focusing lens 47d may also be a known zoom lens capable of changing its focal position under the control of the control unit 40. The imaging surface of the imaging element 45h in the optical system of the refractometer light receiving system 47 is located at the fundus conjugate position P.

[0071] In the refractometer projection system 46, light emitted from the refractometer light source 46a passes through the relay lens 46b and is incident on the conical surface of the conical prism 46c. The refractometer projection system 46 deflects the light incident on the conical surface, which then exits from the bottom of the conical prism 46c, passes through the field lens 46d, and then passes through the annular aperture 46e (its light-transmitting portion). In the refractometer projection system 46, this light (annular beam) is reflected by the reflective surface of the aperture prism 46f, passes through the rotating prism 46g, and is reflected by the dichroic mirror 46h. In the refractometer projection system 46, this reflected light is reflected by the dichroic mirror 45b, passes through the objective lens 45a, and is projected onto the left eye EL.

[0072] The conical prism 46c is preferably positioned as close as possible to the pupil conjugate position Q. For example, the conical prism 46c may have an annular aperture 46e attached to its bottom surface facing the field lens 46d. In this case, for example, a light-shielding film is deposited on the bottom surface of the conical prism 46c to form an annular light-transmitting portion. Alternatively, the annular aperture 46e may be located on the conical surface side of the conical prism 46c.

[0073] Alternatively, the field lens 46d may have an annular aperture 46e attached to its lens surface on the left examined eye EL side. In this case, for example, a light-shielding film is deposited on the lens surface of the field lens 46d to form an annular light-transmitting portion. Furthermore, the refractometer projection system 46 may have a structure that omits the field lens 46d. The annular aperture 46e may also be an aperture with a light-transmitting portion having a shape corresponding to a predetermined measurement pattern. The light-transmitting portion may be formed at a position eccentric with respect to the optical axis of the refractometer projection system 46. Furthermore, the aperture may have two or more light-transmitting portions. The rotating prism 46g is used to average the light intensity distribution of the annular light beam relative to the blood vessels or diseased areas of the fundus Ef, thereby reducing speckle noise caused by the light source.

[0074] In the refractometer light receiving system 47, the return light of the annular beam projected onto the fundus Ef passes through the objective lens 45a and is reflected by the dichroic mirror 45b and the dichroic mirror 46h. In the refractometer light receiving system 47, this reflected return light passes through the rotating prism 46g, the aperture of the aperture prism 46f, and the relay lens 47a, is reflected by the reflective mirror 47b, and then passes through the relay lens 47c and the focusing lens 47d. In the refractometer light receiving system 47, this light is reflected by the reflective mirror 47e, then by the dichroic mirror 45f, and forms an image on the imaging surface of the imaging element 45h through the imaging lens 45g.

[0075] The control unit 40 performs known operations based on the output from the imaging element 45h to calculate ocular refractive power parameters. These ocular refractive power parameters include the refractive value (diopter), spherical power, astigmatism, and astigmatism axis angle of the left and right eyes EL and ER. Based on control signals sent from the examiner's controller 30, the control unit 40 uniformly controls the left and right measurement optical systems 25L and 25R, including the refraction measurement projection system 46, the refraction measurement light receiving system 47, and the sight mark projection system 44, as well as various components of the measurement unit 20. Furthermore, the control unit 40 transmits the measurement results of the ocular characteristics of the left and right eyes EL and ER, measured by the measurement head 122, to the examiner's controller 30.

[0076] Next, use Figures 5 to 7The optotype Ot used in the eye fatigue estimation process is described. The optotype Ot includes an optotype OtL for the left eye presented to the left eye EL by the left measurement optical system 25L, and an optotype OtR for the right eye presented to the right eye ER by the right measurement optical system 25R. In each display 44a of the left measurement optical system 25L and the right measurement optical system 25R, the optotype Ot of Example 1 is formed so as to display a white mark on a black background. Figure 5 As shown, the left-eye optotype OtL and the right-eye optotype OtR have first optotype markers s1 and second optotype markers s2 of the same shape and size. Hereinafter, when shown separately, the left-eye optotype OtL is referred to as the left first optotype marker s1L and the left second optotype marker s2L, and the right-eye optotype OtR is referred to as the right first optotype marker s1R and the right second optotype marker s2R.

[0077] The two first visual markers s1 are asterisk patterns, which are respectively displayed at the center position of the display 44a of a rectangular shape such as a liquid crystal frame. The two second visual markers s2 are circular patterns that respectively surround the first visual marker s1. For the two second visual markers s2, when the two second visual markers s2 are fused, the convergence angle θc becomes smaller and the convergence distance Lc becomes larger (farther) compared to when the two first visual markers s1 are fused. In detail, it is assumed that the center position of the left second visual marker s2L is biased to the outside (left side) than the center position of the left first visual marker s1L, and the center position of the right second visual marker s2R is biased to the outside (right side) than the center position of the right first visual marker s1R. Moreover, the eccentricity of the left second visual marker s2L and the right second visual marker s2R from the center position of the display 44a to the outside is the same. Therefore, the left-eye optotype OtL and the right-eye optotype OtR are configured such that the first optotype symbol s1 and the second optotype symbol s2, which have the same pattern, size, and line width, are flipped left and right on their respective displays 44a. The pattern, size, and line width of the first optotype symbol s1 and the second optotype symbol s2 are determined so that when single vision fusion is performed by converging the images projected on the retina into one, appropriate fusion stimulation is provided to the left and right examinee eyes E (EL, ER).

[0078] Regarding the left eye optotype OtL and the right eye optotype OtR, if the first optotype symbol s1 is fixed and the two eyes are visually focused to fuse them, Figure 6 As shown, outside the single first optotype mark s1, two second optotype marks s2 appear to overlap left and right. Figure 7 As shown, inside the single second visual mark s2, two first visual mark s1 appear to be arranged left and right.

[0079] Next, use Figure 8 The flowchart shows the structure and the flow of operations of the eye fatigue estimation process executed in the ophthalmologic apparatus 1. The measurement process is started by selecting a mode for estimating the degree of fatigue of the eye to be examined in the ophthalmologic apparatus 1.

[0080] In step S1, the eye refractive power is measured and the process proceeds to step S2. In step S1, the control unit 40 measures the eye refractive power of the left eye EL and the right eye ER. Specifically, the control unit 40 first aligns the left measuring unit 24L with respect to the left eye EL and the right measuring unit 24R with respect to the right eye ER. Next, the control unit 40 implements cloud control while the left eye EL and the right eye ER are fixating on the fixation mark, and measures the eye refractive power of the left and right eyes E (EL, ER) based on the annular image generated by the fundus reflected light obtained using the refraction measurement projection system 46 and the refraction measurement light receiving system 47. Based on the measured eye refractive power, the position of the focusing lens 44e in the sight mark projection system 44 is adjusted so that the spherical diopter of the left eye EL and the right eye ER is in a fully corrected state at the position where the inspection distance is hyperopia. Thereafter, subjective refraction can be performed and the position of the far point can be determined in more detail to determine the position of the focusing lens 44e in the sight mark projection system 44.

[0081] In step S2, the optotype Ot is presented, and the process proceeds to step S3. In step S2, the control unit 40 controls the optotype projection system 44 of the left measurement optical system 25L to display the left-eye optotype OtL on the display 44a, and controls the optotype projection system 441 of the right measurement optical system 25R to display the right-eye optotype OtR on the display 44a. At this time, the control unit 40 sets the optotype presentation distance Lp between the left-eye optotype OtL and the right-eye optotype OtR to an arbitrary equal distance, and sets the left-eye optotype OtL and the right-eye optotype OtR to the same brightness (contrast of the optotype relative to the background). Furthermore, the control unit 40 controls the drive mechanism 23 (the left-eye drive mechanism 23L and the right-eye drive mechanism 23R) to adjust the position (orientation) of the left measurement unit 24L and the right measurement unit 24R, setting the convergence angle θc relative to the optotype Ot to an arbitrary angle. In Example 1, the sight mark presentation distance Lp is set to 33 cm, and the convergence angle θc is further set inward by 20Δ (prism) from the state in which the convergence distance Lc matches the sight mark presentation distance Lp (10Δ for each of the left and right eyes E (EL, ER)). At this time, the convergence distance Lc when the fusion image is the second sight mark symbol s2 is not greater than the sight mark presentation distance Lp. In addition, the sight mark presentation distance Lp and the convergence angle θc can be appropriately set according to the age and visual acuity of the subject, and are not limited to the structure of Example 1. In addition, in the ophthalmologic apparatus 1 of Example 1, when the sight mark Ot is presented, the control unit 40 displays the anterior ocular images E′ of the left eye EL and the right eye ER obtained by the anterior ocular observation system 45 on the display unit 31 of the examiner's controller 30. The display of the anterior ocular image E′ continues until the eye fatigue estimation process is completed.

[0082] In step S3, the reference gaze directions SL and SR are detected, and the process proceeds to step S4. In step S3, the subject is caused to fuse a common portion of the optotype Ot presented in step S2, and the gaze directions SL and SR in this state are detected. In Example 1, after confirming that the subject has converged on the first optotype symbol s1 and has achieved fusion, the control unit 40 detects the reference gaze direction SL for the left eye EL and the reference gaze direction SR for the right eye ER. Therefore, the reference gaze directions SL and SR are the gaze directions of the left eye EL and the right eye ER in a state where the subject has achieved fusion of the first optotype symbol s1, which is a common portion of the optotype Ot. These gaze directions SL and SR are detected based on the anterior ocular segment images E′ of the left eye EL and the right eye ER acquired by the anterior ocular segment observation system 45 and the rotation angles of the left and right measurement units 24L and 24R controlled by the drive mechanism 23. Therefore, the anterior ocular segment observation system 45 functions as an eye information acquisition unit that acquires eye information for detecting the gaze direction SL of the left eye EL and the gaze direction SR of the right eye ER. In the ophthalmologic apparatus 1 of Example 1, the control unit 40 displays the gaze directions SL and SR (their information) as a reference, which are detection results, on the display unit 31 of the examiner controller 30.

[0083] If, in step S3, it is determined that fusion is not yet achieved, the subject is directed to look at the first optotype marker s1 again to re-acquire the reference gaze directions SL and SR. This lack of fusion can be determined by a significant difference between the convergence angle θc obtained from the acquired gaze directions SL and SR and the convergence angle θc set in step S2, indicating that the subject is seeing the first optotype marker s1 twice. Furthermore, if re-acquiring the gaze directions SL and SR does not improve the condition, the control unit 40 may return to step S2, change the optotype presentation distance Lp or the convergence angle θc for presenting the optotype Ot, and then proceed to step S3 again. At this time, by increasing the sight mark presentation distance Lp, or reducing the convergence angle θc, or making the convergence distance Lc based on the convergence angle θc close to the sight mark presentation distance Lp, or considering the oblique angle of the examined eye E to set the convergence distance Lc based on the convergence angle θc and the sight mark presentation distance Lp, fusion can be facilitated.

[0084] In step S4, the brightness difference is expanded and the process proceeds to step S5. In this step S4, the control unit 40 controls the left and right displays 44a to expand the brightness difference (contrast difference) between the brightness of the left first visual mark s1L of the left eye visual mark OtL and the brightness of the right first visual mark s1R of the right eye visual mark OtR by only a predetermined amount. In step S4 of Example 1, the brightness of one of the left first visual mark s1L and the right first visual mark s1R is reduced, and the brightness of the other is fixed (maintained), thereby expanding the brightness difference. The brightness difference can be expanded continuously or in stages over time. Therefore, the brightness difference (contrast difference) between the left first visual mark s1L and the right first visual mark s1R is expanded continuously or in stages over time, and the first visual mark s1 with reduced brightness becomes difficult to see.

[0085] In step S5, the gaze directions SL and SR are detected, and the process proceeds to step S6. In step S5, the control unit 40 detects the gaze directions SL of the left eye EL and SR of the right eye ER using the same SR detection method as in step S3. The control unit 40 displays the gaze directions SL and SR (their information) as the detection results on the display unit 31 of the examiner controller 30.

[0086] In step S6, the focus position is detected and the process proceeds to step S7. In step S6, the control unit 40 detects the focus position of the left eye EL (the eye refractive value when observing at a predetermined position) and the focus position of the right eye ER (the eye refractive value when observing at a predetermined position). The control unit 40 detects the focus position based on the annular image of the fundus reflected light obtained using the refractometer projection system 46 and the refractometer light receiving system 47. That is, the control unit 40 calculates the focus position (adjustment position) on the visual axis of each eye based on the refractive power of the left eye EL or the right eye ER. Therefore, the refractometer projection system 46 and the refractometer light receiving system 47 function as an eye information acquisition unit that acquires eye information for detecting the focus position of the left eye EL and the right eye ER.

[0087] In step S7, a determination is made as to whether fusion is disrupted. If so, the process proceeds to step S8; if not, the process proceeds to step S4. In step S7, the control unit 40 determines whether fusion is disrupted based on the reference gaze directions SL and SR detected in step S3, the gaze directions SL and SR detected in step S5, and the focal positions of the left and right eyes E (EL and ER) detected in step S6. In Example 1, changes in the gaze directions SL and SR (eye position shift) are determined based on whether they have shifted by a predetermined amount (e.g., ±0.5°) relative to the reference gaze directions SL and SR. If so, the fusion of the first visual marker s1 is determined to be disrupted. Alternatively, the control unit 40 can determine that fusion is disrupted if it detects that the gaze directions SL and SR are directed toward the second visual marker s2. Whether the focus is directed toward the second optotype marker s2 can be determined based on the position of the second optotype marker s2 on the display 44a, the optotype presentation distance Lp of the presented optotype Ot, and the convergence angle θc. Furthermore, in Example 1, if the focus position of the left eye EL and the right eye ER deviates from the optotype presentation distance Lp of the optotype Ot by a predetermined amount (e.g., ±1.0D in diopter conversion) or more, it is determined that the fusion of the first optotype marker s1 is disrupted.

[0088] In this manner, the control unit 40 repeatedly executes the process from steps S4 to S7 until it determines in step S7 that fusion is broken. Consequently, the brightness difference between the left first optotype symbol s1L of the left-eye optotype OtL and the right first optotype symbol s1R of the right-eye optotype OtR increases over time until fusion of the first optotype symbol s1 is broken. At this point, the display unit 31 continues to display the anterior ocular segment images E' of the left and right eyes E (EL, ER) and the detection results of the gaze directions SL and SR. This allows the examiner to understand the status of the left and right eyes E (EL, ER) in real time.

[0089] In step S8, the fusional disruption luminance difference is determined, and the process proceeds to step S9. In step S8, the control unit 40 obtains the luminance difference between the left first optometrist marker s1L and the right first optometrist marker s1R at the time when fusion was determined to be disrupted in step S7, i.e., the fusional disruption luminance difference. The control unit 40 appropriately displays the obtained fusional disruption luminance difference (information thereof) on the display unit 31 of the examiner controller 30.

[0090] In step S9, asthenopia is estimated, and the asthenopia estimation process ends. In step S9, the control unit 40 estimates asthenopia for the left and right examinee eyes E (EL, ER) based on the information on the fusional disruption luminance difference at the time when fusion was determined to be disrupted, as determined in step S8, and displays the estimated result appropriately on the display unit 31 of the examiner's controller 30. For example, the control unit 40 compares the fusional disruption luminance difference with the fusional disruption luminance difference during a different examination of the examinee. If the fusional disruption luminance difference in the current measurement is smaller (if fusion was disrupted quickly), the control unit 40 determines that the asthenopia level is higher (fatigue) in this measurement. Alternatively, the control unit 40 may pre-obtain a typical fusional disruption luminance difference and compare this typical fusional disruption luminance difference with the fusional disruption luminance difference during the current measurement to determine whether the examinee is experiencing asthenopia. Furthermore, the control unit 40 may pre-obtain the fusional disruption luminance difference of multiple examinees, determine the relationship between fatigue level (quantified, etc.) and this fusional disruption luminance difference, and calculate the asthenopia level based on this relationship.

[0091] Next, the flow of the asthenopia estimation process (each step) described above will be described. In this asthenopia estimation process, the subject faces the ophthalmologic apparatus 1, positions their face in a predetermined position, selects a mode for estimating the degree of asthenopia in the eye under examination, and proceeds to steps S1 → S2 → S3. The control unit 40 then measures the refractive power of the left and right eyes under examination E (EL, ER) and presents the sight mark Ot at a predetermined sight mark presentation distance Lp and convergence angle θc. The control unit 40 then detects the reference gaze directions SL and SR of the left and right eyes under examination E (EL, ER) while fusion is performed on the first sight mark symbol s1, which is a common part of the sight mark Ot.

[0092] After that, the asthenopia estimation process enters steps S4→S5→S6, and the control unit 40 expands the brightness difference between the left first visual mark s1L and the right first visual mark s1R, and detects the line of sight SL, SR and focus position of the left and right eyes E (EL, ER). Next, in the asthenopia estimation process, step S7 is entered, and based on the reference line of sight SL, SR, the current line of sight SL, SR and focus position, it is determined whether fusion is destroyed. Then, in the asthenopia estimation process, steps S4→S5→S6→S7 are repeated until it is determined that fusion is destroyed. If it is determined that fusion is destroyed, the process enters steps S8→S9. Then, the control unit 40 determines the fusion destruction brightness difference at the time point when fusion is destroyed, and estimates asthenopia based on this fusion destruction brightness difference. In addition, the brightness can be reduced only for a single eye (for example, the non-dominant eye), or it can be reduced for both eyes in sequence.

[0093] Thus, in the asthenopia estimation process, while the first visual marker s1 is being visually observed and fused, the luminance difference between the left first visual marker s1L and the right first visual marker s1R is increased, and asthenopia is estimated based on the fusional luminance difference when fusion is broken. Therefore, in order to appropriately estimate asthenopia in the asthenopia estimation process, it is necessary to appropriately detect the timing of fusional breakage and obtain an appropriate fusional breakage luminance difference. In the asthenopia estimation process, when the luminance difference is increased, the current gaze directions SL and SR are detected to confirm whether there is any change (eye position deviation) from the reference gaze directions SL and SR, thereby detecting the timing of fusional breakage. In this asthenopia estimation process, the gaze directions SL and SR are detected based on the anterior ocular image E′ of the actual condition of the subject's eye, which is obtained in real time by the anterior ocular segment observation system 45, and the rotation angles of the left measurement unit 24L and the right measurement unit 24R. Therefore, compared with detecting the timing of fusional disruption based on the subject's response, the timing of fusional disruption can be detected more appropriately.

[0094] As described above, this asthenopia estimation process utilizes the fact that when fusion of the first visual marker s1 is disrupted, the gaze directions SL and SR of the left and right eyes E (EL, ER) shift from the left first visual marker s1L and the right first visual marker s1R to other directions (eye position shift). In other words, even if fusion of the first visual marker s1 is disrupted, the disruption of fusion cannot be detected unless the gaze directions SL and SR deviate from the left first visual marker s1L and the right first visual marker s1R.

[0095] In the case where the optotype Ot consists only of the first optotype marker s1, the following situation may occur. To simplify the explanation, it is assumed that the brightness difference between the left first optotype marker s1L and the right first optotype marker s1R is increased by reducing the brightness of the right first optotype marker s1R. Due to the reduction in the brightness of the right first optotype marker s1R, the right eye ER becomes difficult to see the right first optotype marker s1R, and ultimately becomes difficult to visually confirm the right first optotype marker s1R. As a result, the right eye ER no longer has an object to look at, and therefore the state of looking at the first optotype marker s1 is released, and the line of sight SR deviates from the first optotype marker s1. In the case where the optotype Ot consists only of the first optotype marker s1, if it becomes difficult to visually confirm the right first optotype marker s1R, there is no object to look at, and therefore, there is a situation where the line of sight SR does not change from the state of looking at the first optotype marker s1. As a result, it becomes impossible to detect the change in the line of sight SR, and therefore it becomes impossible to properly detect the timing of the destruction of fusion.

[0096] Furthermore, since the optotype Ot is displayed and presented on the display 44a, if the optotype Ot is formed by displaying a white mark on a black background as in Example 1, then if the brightness of the right first optotype marker s1R is reduced (approximately turning off the lights), the edge of the display 44a becomes conspicuous. This is because reducing the brightness of the right first optotype marker s1R darkens the entire screen, and the edge of the display 44a appears slightly illuminated due to the backlight. Consequently, the edge of the display 44a becomes a fusional stimulus. If the gaze direction SR (center position) of the right first optotype marker s1R and the edge of the display 44a are the same, even if fusion of the first optotype marker s1 is disrupted, the gaze direction SR does not change, making it difficult to detect the timing of fusional disruption.

[0097] In response to this, the ophthalmologic apparatus 1 disclosed herein sets the visual mark Ot to include a first visual mark s1 and a second visual mark s2 having a different parallax from that of the first visual mark s1. Then, in the ophthalmologic apparatus 1, during the eye fatigue estimation process, the brightness difference between only the first visual mark s1 and the second visual mark s2 that is being looked at is increased. Therefore, if the fusion image of the first visual mark s1 is released, the line of sight SL and SR of the inspected eye E that has become difficult to see is directed toward the second visual mark s2. Specifically, the situation becomes as follows. Below, for simplicity of explanation, it is assumed that the brightness difference between the left first visual mark s1L and the right first visual mark s1R is increased by reducing the brightness of the right first visual mark s1R.

[0098] first, Figure 9 The figure shows a situation where the left eye EL is presented with a left-eye optotype OtL, and the right eye ER is presented with a right-eye optotype OtR. The left eye EL and the right eye ER each focus on the left first optotype marker s1L and the right first optotype marker s1R, respectively, allowing both eyes to visually view the first optotype marker s1 and achieve fusion. At this time, the left first optotype marker s1L and the left second optotype marker s2L of the left optotype OtL and the right first optotype marker s1R and the right second optotype marker s2R of the right optotype OtR are all displayed brightly in the same manner, allowing both eyes to visually view the first optotype marker s1 and achieve fusion. Therefore, the left eye EL is in a line of sight direction SL toward the left first optotype marker s1L, and the right eye ER is in a line of sight direction SR toward the right first optotype marker s1R.

[0099] Then, if Figure 10As shown, the brightness is reduced to the point where it becomes difficult to visually confirm the right first visual mark s1R of the right eye visual mark OtR, and the brightness of the other left first visual mark s1L, left second visual mark s2L, and right second visual mark s2R are fixed (maintained). Therefore, if it becomes difficult for the right eye ER to see the right first visual mark s1R, it is guided to see the right second visual mark s2R whose brightness is fixed (maintained), and the line of sight SR is changed to be toward the right second visual mark s2R. At this time, the brightness of the left first visual mark s1L is fixed (maintained), so the subject maintains the line of sight SL toward the left first visual mark s1L by gazing at the left first visual mark s1L. In addition, because it becomes difficult for the right eye ER to see the right first visual mark s1R, it is stimulated by the fusion of the right second visual mark s2R, thereby Figure 11 As shown, the left eye EL is also guided to look at the left second visual mark s2L, and the line of sight SL is changed to the right second visual mark s2R. However, it can also be judged that this is different from the case where only the right eye ER is changed to the right second visual mark s2R ( Figure 10 ) compared to the case where the left eye EL also changes to the left second visual mark s2L ( Figure 11 ) has a higher level of eye fatigue (tiredness).

[0100] In this way, the ophthalmologic apparatus 1 configures the optotype Ot to include a first optotype marker s1 and a second optotype marker s2 having a different parallax from the first optotype marker s1. Therefore, when visual confirmation of the right first optotype marker s1R becomes difficult, guidance can be provided by directing the eye to the right second optotype marker s2R having a different parallax. Therefore, when visual confirmation of the right first optotype marker s1R becomes difficult, the ophthalmologic apparatus 1 can change the gaze direction SR of the right examinee's eye ER from toward the right first optotype marker s1R to toward the right second optotype marker s2R. This allows the ophthalmologic apparatus 1 to appropriately detect when fusion of the right first optotype marker s1R is disrupted.

[0101] In particular, in the ophthalmologic apparatus 1 of Example 1, the convergence distance Lc of the convergence angle θc of the first optometry mark s1 is set to be smaller than the optotype presentation distance Lp, and the convergence angle θc of the second optometry mark s2 is set to be smaller than the convergence angle θc of the first optometry mark s1. Therefore, when visual confirmation of the right first optometry mark s1R becomes difficult, the right second optometry mark s2R is located in the diverging direction and in the direction close to the optotype presentation distance Lp for the right eye ER. This allows the gaze direction SR of the right eye ER to more naturally align with the right second optometry mark s2R. Consequently, in the ophthalmologic apparatus 1, when visual confirmation of the right first optometry mark s1R becomes difficult, the gaze direction SR of the right eye ER can be more reliably aligned with the right second optometry mark s2R, enabling more reliable detection of changes in the gaze direction SR.

[0102] Furthermore, in the ophthalmic device 1 of Example 1, the control unit 40 detects the focus position of the left eye EL and the right eye ER when detecting the gaze directions SL and SR of the left and right eyes E (EL, ER). The control unit 40 can determine the position (distance) at which the left and right eyes EL and ER are visually viewing based on the focus position detection results. Therefore, when the control unit 40 determines whether the gaze directions SL and SR have changed by detecting the focus positions of the left and right eyes E (EL, ER), it can appropriately determine whether the eyes are viewing the right first sight mark s1R or the right second sight mark s2R based on the focus position determination results, thereby improving the accuracy of determining whether the gaze directions SL and SR have changed.

[0103] Furthermore, in the ophthalmologic apparatus 1 of Example 1, while gradually increasing the brightness difference of a portion of the optotype Ot, the control unit 40 simultaneously increases the brightness difference (contrast difference) between the left and right optotypes Ot, and displays the ocular information acquired by the anterior ocular segment observation system 45, namely, the anterior ocular segment images E' of the left and right examinee eyes EL and ER, on the display unit 31. The anterior ocular segment images E' of the left and right examinee eyes E (EL, ER) are ocular information used to detect the gaze directions SL and SR. Therefore, by visually checking the display unit 31, the examiner can monitor the movement of the left and right examinee eyes E (EL, ER) during the period of increasing brightness difference of a portion of the optotype Ot, and can determine whether the gaze directions SL and SR have changed. This determination allows the examiner to determine whether the fusion image has disrupted the brightness difference and estimate asthenopia. Furthermore, the examiner can also determine whether the gaze directions SL and SR have changed by directly observing the movement of the examinee's left and right examinee eyes E (EL, ER).

[0104] In the ophthalmologic apparatus 1 of Example 1, the second optometry mark s2 is provided as a circular pattern surrounding the first optometry mark s1 in the optometry mark Ot. Therefore, the displacement between the center positions of the first optometry mark s1 and the second optometry mark s2, i.e., the parallax between the first optometry mark s1 and the second optometry mark s2, can be reduced. Consequently, when it becomes difficult to visually confirm the right first optometry mark s1R, the gaze direction SR of the right eye ER can be more reliably directed toward the right second optometry mark s2R.

[0105] The ophthalmologic apparatus 1 according to the first embodiment of the present disclosure can obtain the following operational effects.

[0106] The ophthalmologic apparatus 1 includes an optotype projection system 44 serving as an optotype presentation mechanism for presenting a left-eye optotype OtL to the left eye EL and a right-eye optotype OtR to the right eye ER. The optotype projection system 44 provides the left-eye optotype OtL and the right-eye optotype OtR in the same form. Furthermore, the optotype projection system 44 presents the left-eye optotype OtL to the left eye EL and the right-eye optotype OtR to the right eye ER, increasing the brightness difference between the common portion of the left-eye optotype OtL and the right-eye optotype OtR while maintaining the brightness difference between the remaining portions of the left-eye optotype OtL and the right-eye optotype OtR. Therefore, in the ophthalmologic apparatus 1, when the fusion image of the common portion of the left-eye optotype OtL and the right-eye optotype OtR is disrupted, the gaze directions SL and SR of the examined eye E, which has become difficult to see, can be guided to the remaining positions of the left-eye optotype OtL and the right-eye optotype OtR, thereby reliably detecting changes in the gaze directions SL and SR (eye position shift). Thus, the ophthalmologic apparatus 1 can appropriately detect the timing of fusion image disruption and appropriately estimate eye fatigue based on this timing.

[0107] Furthermore, in the ophthalmologic apparatus 1, the left-eye optotype OtL and the right-eye optotype OtR have two or more optotype marks (s1, s2) of the same shape, and the parallax of at least one optotype mark (s1, s2) is different. Therefore, by increasing the brightness difference of one optotype mark while maintaining the brightness difference of the remaining optotype marks, the ophthalmologic apparatus 1 can guide the gaze directions SL and SR of the examined eye E toward the remaining optotype marks if one optotype mark becomes difficult to see. Consequently, the ophthalmologic apparatus 1 can more reliably detect changes in the gaze directions SL and SR (eye position shift).

[0108] The ophthalmologic apparatus 1 further includes a drive mechanism 23 serving as a convergence adjustment mechanism for adjusting the convergence angle θc, an anterior ocular segment observation system 45, a refractometry projection system 46, and a refractometry light receiving system 47 serving as an eye information acquisition unit for acquiring eye information of the left eye EL and the right eye ER, and a control unit 40 for controlling the optotype projection system 44, the drive mechanism 23, the anterior ocular segment observation system 45, the refractometry projection system 46, and the refractometry light receiving system 47. The control unit 40 controls the drive mechanism 23 to set an arbitrary convergence angle θc and controls the optotype projection system 44 to present the left eye optotype OtL and the right eye optotype OtR at equal optotype presentation distances Lp, thereby increasing the brightness difference between one optotype symbol (s1, s2) between the left eye optotype OtL and the right eye optotype OtR while maintaining the brightness difference between the other optotype symbols (s1, s2). At this time, the control unit 40 detects the gaze direction SL of the left eye EL and the gaze direction SR of the right eye ER based on the eye information acquired by the anterior ocular segment observation system 45, the refractometry projection system 46, and the refractometry light receiving system 47, determines the timing at which fusion of the left eye EL and the right eye ER is broken, and estimates the degree of fatigue based on the timing of the fusional breakdown. Therefore, the ophthalmologic apparatus 1 can appropriately determine the timing at which fusional breakdown occurs and appropriately estimate the degree of fatigue.

[0109] In the ophthalmologic apparatus 1, the left-eye optotype OtL and the right-eye optotype OtR include at least a first optotype marker s1 of identical shape and a second optotype marker s2 of identical shape with a smaller convergence angle θc than the first optotype marker s1. The control unit 40 increases the brightness difference of the first optotype marker s1 while maintaining the brightness difference of the second optotype marker s2. Therefore, in the ophthalmologic apparatus 1, when it becomes difficult to visually confirm the first optotype marker s1, the presence of the second optotype marker s2L in the diverging direction allows the inspected eye E to more naturally align its line of sight SL and SR with the second optotype marker s2L.

[0110] The ophthalmologic apparatus 1 further includes at least a display unit 31 that can be visually recognized by the examiner, and the control unit 40 displays the fatigue level estimation result on the display unit 31. Therefore, the ophthalmologic apparatus 1 can easily grasp the fatigue level estimation result.

[0111] In the ophthalmologic apparatus 1, the control unit 40 displays the eye information acquired by the anterior ocular segment observation system 45, the refractometry projection system 46, and the refractometry light receiving system 47, which serve as the eye information acquisition unit, on the display unit 31 while gradually increasing the brightness difference via the optotype projection system 44, which serves as an optotype presentation mechanism. Therefore, in the ophthalmologic apparatus 1, the examiner can monitor the movement of the left and right eyes EL, ER while the brightness difference between the optotypes increases by visually checking the display unit 31, and can also determine whether there has been a change in the line of sight directions SL, SR.

[0112] In the ophthalmic apparatus 1, the control unit 40 can set the convergence distance Lc, represented by the convergence angle θc, to be shorter than the optotype presentation distance Lp. Therefore, in the ophthalmic apparatus 1, a portion of the left-eye optotype OtL and the right-eye optotype OtR can be fused in the converged state. When fusion is disrupted, the gaze directions SL and SR can be induced to change, making it easy to identify the timing of fusion disruption.

[0113] In the ophthalmologic apparatus 1, the optotype projection system 44, which serves as an optotype presentation mechanism, includes a display 44a, which serves as a left-eye display and presents the left-eye optotype OtL and can arbitrarily change the brightness of the left-eye optotype OtL; and a display 44a, which serves as a right-eye display and presents the right-eye optotype OtR and can arbitrarily change the brightness of the right-eye optotype OtR. Therefore, the ophthalmologic apparatus 1 can finely change the brightness of the left-eye optotype OtL and the right-eye optotype OtR, respectively, and can appropriately increase the brightness difference between them.

[0114] In the ophthalmologic apparatus 1, the control unit 40 detects the focus position of the left eye EL and the right eye ER when detecting the gaze directions SL and SR of the left and right eyes EL and ER, respectively, based on eye information acquired by the anterior ocular segment observation system 45, the refractometry projection system 46, and the refractometry light receiving system 47, which serve as the eye information acquisition unit. Therefore, when determining whether the gaze directions SL and SR have changed, the ophthalmologic apparatus 1 can appropriately determine whether the eye is looking at the right first vision marker s1R or the right second vision marker s2R based on the focus position determination result, thereby improving the accuracy of determining whether the gaze directions SL and SR have changed.

[0115] Therefore, in the ophthalmologic apparatus 1 as one embodiment of the present disclosure, it is possible to easily detect eye position deviation when the luminance difference of the optotype Ot presented to the left and right examinee's eyes E is increased from the binocular vision state.

[0116] The ophthalmic device of the present disclosure has been described above based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and design changes and additions are permitted without departing from the spirit of the invention in each of the claims.

[0117] For example, in Example 1, an ophthalmic device 1 is described as an example of an application that observes, captures, and records an image of the anterior segment of a subject's eye, an image of the fundus of a subject's eye, and a tomographic image of the fundus of a subject's eye, providing the image as an electronic image for diagnosis. However, in a state where both eyes are visually viewing a left-eye optotype OtL and a right-eye optotype OtR, any ophthalmic device, whether subjective or objective, can be applied, and the device is not limited to the configuration of Example 1, as long as the device can increase the brightness difference between the common portion of the left-eye optotype OtL and the right-eye optotype OtR while maintaining the brightness difference between the remaining portions of the left-eye optotype OtL and the right-eye optotype OtR.

[0118] In the first embodiment, the first visual mark s1 is set to an asterisk pattern, and the second visual mark s2 is set to a circular pattern. However, the first visual mark s1 and the second visual mark s2 can be different patterns, and are not limited to the structure of the first embodiment. In addition, the second visual mark s2 surrounds the first visual mark s1, but if Figure 12 As shown, it can also be arranged in the horizontal direction of the first view mark s1, and is not limited to the structure of Example 1.

[0119] Furthermore, in Example 1, the first visual mark s1 is displayed at the center of the display 44a, and the second visual mark s2 is displayed at a position eccentric outward from the center of the display 44a. However, as long as the convergence angle θc of the second visual mark s2 is smaller than that of the first visual mark s1, the first visual mark s1 may be displayed eccentrically inwardly and the second visual mark s2 at the center, or the first visual mark s1 may be displayed eccentrically inwardly and the second visual mark s2 may be displayed eccentrically outwardly, without being limited to the configuration of Example 1.

[0120] In Example 1, the optotype Ot (first optotype mark s1, second optotype mark s2) is formed as a white mark displayed on a black background. However, as long as the optotype Ot can be visually confirmed and the first optotype mark s1 and the second optotype mark s2 can be fused, the background and mark colors can be set as appropriate, and are not limited to the configuration of Example 1.

[0121] In Example 1, the optotype presentation mechanism includes two optotype projection systems 44, each corresponding to the left and right eyes E (EL, ER). Each optotype projection system 44 includes a display 44a capable of displaying an arbitrary optotype and varying its brightness. However, the optotype presentation mechanism is not limited to the structure of Example 1, as long as it has the function of increasing the brightness difference between one of the two first optotype symbols s1 and the two second optotype symbols s2 while maintaining a state of no brightness difference between the other. For example, the optotype presentation mechanism may be a mechanism in which a liquid crystal shutter is disposed between the optotype and the left and right eyes E (EL, ER), and the transmittance of the liquid crystal shutter is locally varied. Furthermore, as long as the optotype presentation mechanism has the aforementioned functions, it is not necessary to provide separate optotype presentation mechanisms for the left and right eyes.

[0122] In the ophthalmologic apparatus 1 of Example 1, the focus positions of the left and right eyes E (EL, ER) are detected when determining whether the gaze directions SL and SR have changed. However, since the focus positions are detected to ensure accuracy when determining changes in the gaze directions SL and SR, detection is not essential.

[0123] In the ophthalmologic apparatus 1 of Example 1, the results of the estimated fatigue levels of the left and right eyes E (EL, ER) to be examined, and the anterior ocular images E′ of the left and right eyes E (EL, ER) to be examined when the brightness difference of the optotype is gradually increased, are displayed on the display unit 31 of the examiner's controller 30. However, the display unit only needs to be at least visible to the examiner, and, for example, a monitor provided on the optometry table 12 or a display provided on the measurement unit 20 may be used.

[0124] In the ophthalmic device 1 of Example 1, the expansion of the brightness difference of the common portion of the optotype Ot is stopped at the point in time when the gaze directions SL and SR begin to change (generate), and the fusional disruption brightness difference is determined. However, the control unit 40 may continue detecting changes in the gaze directions SL and SR until the brightness of a portion of one optotype Ot reaches zero, that is, until the portion of one optotype Ot becomes the same color as the background. Alternatively, the gaze directions SL and SR may be continuously acquired by changing the brightness difference by a small amount or by continuously changing the brightness difference. Furthermore, the tilt may be detected from a graph showing the relationship between the gaze directions SL and SR and the brightness difference, and the portion with the largest change may be used as the fusional disruption brightness difference. Furthermore, the focus position may be continuously acquired, and the degree of focus position fluctuation may be large as the fusional disruption brightness difference. Alternatively, the change in the gaze directions SL and SR may be combined with the focus position fluctuation to determine the fusional disruption brightness difference.

[0125] In the ophthalmic device 1 of Example 1, the optotype Ot includes a first optotype marker s1 and a second optotype marker s2. However, the optotype may include three or more optotype markers, as long as the optotype includes multiple optotype markers with different parallaxes, and is not limited to the configuration of Example 1. For example, in a configuration including a third optotype marker in addition to the first optotype marker s1 and the second optotype marker s2, by arranging the third optotype marker offset inward from the first optotype marker s1, when it becomes difficult to visually confirm the first optotype marker s1, even when the line of sight tends to shift in the convergence direction, the eye can naturally turn toward the third optotype marker, thereby reliably detecting the movement of the line of sight directions SL and SR from the first optotype marker s1.

[0126] In the ophthalmologic apparatus 1 of Example 1, the optotype Ot includes a first optotype marker s1 and a second optotype marker s2. However, the optotype Ot may utilize the edge of the display 44a as the second optotype marker s2, that is, only the first optotype marker s1 may be depicted on the display 44a. In this case, the first optotype marker s1 is depicted inward from the center of the display 44a (to the right for the left first optotype marker s1L and to the left for the right first optotype marker s1R), rather than at the center of the display 44a. Furthermore, while the first optotype marker s1 is being fused, the brightness difference between the left first optotype marker s1L and the right first optotype marker s1R is increased, and the brightness difference when the line of sight SL and SR are moved or when the response is such that two first optotype markers s1 appear is used as the fusion-breaking brightness difference. When the first optotype mark s1 becomes difficult to visually confirm, the optotype mark Ot can guide the line of sight SL and SR of the examinee's eye E toward the edge of the display 44a, which is the second optotype mark s2, thereby achieving the same effect as in the first embodiment. [1]

[0128] An ophthalmic device, characterized in that

[0129] The device has an optotype presenting mechanism for presenting an optotype for the left eye to the left eye under examination and an optotype for the right eye to the right eye under examination.

[0130] The left eye optotype and the right eye optotype are of the same form,

[0131] The optotype presentation mechanism presents the left-eye optotype to the left eye under examination and presents the right-eye optotype to the right eye under examination, thereby expanding the brightness difference of the common part of the left-eye optotype and the right-eye optotype and maintaining the brightness difference of the remaining part of the left-eye optotype and the right-eye optotype. [2]

[0133] The ophthalmologic apparatus according to [1] is characterized in that the left-eye optotype and the right-eye optotype have two or more optotype symbols of the same shape, and at least one of the optotype symbols has a different parallax. [3]

[0135] The ophthalmic device according to [2] is characterized in that

[0136] The distance from the left eye to be examined to the left eye optotype and the distance from the right eye to the right eye optotype are used as optotype presentation distances.

[0137] The position where the sight lines of the left eye under examination intersect with the sight lines of the right eye under examination is defined as the sight line intersection point, and the angle formed by the line segments connecting the left eye under examination and the right eye under examination and the sight line intersection point is defined as the convergence angle.

[0138] The ophthalmic device further comprises:

[0139] A convergence adjustment mechanism adjusts the convergence angle.

[0140] an eye information acquisition unit that acquires eye information of the left eye to be examined and the right eye to be examined, and

[0141] a control unit, configured to control the visual mark presenting mechanism, the convergence adjusting mechanism, and the eye information acquiring unit;

[0142] The control unit controls the convergence adjustment mechanism to be set to an arbitrary convergence angle and controls the optotype presentation mechanism to present the left eye optotype and the right eye optotype at mutually equal optotype presentation distances, thereby expanding the brightness difference between one of the optotype symbols of the left eye optotype and the right eye optotype and maintaining the brightness difference between the other optotype symbols, detects the gaze direction of the left eye under examination and the gaze direction of the right eye under examination based on the eye information obtained by the eye information acquisition unit, calculates the timing when the fusion of the left eye under examination and the right eye under examination is destroyed, and estimates the fatigue level based on the timing when the fusion is destroyed. [4]

[0144] The ophthalmic device according to [3] is characterized in that

[0145] The left-eye optotype and the right-eye optotype have at least a first optotype symbol of the same shape and a second optotype symbol of the same shape with a smaller convergence angle than the first optotype symbol.

[0146] The control unit increases the brightness difference of the first visual mark symbol and maintains the brightness difference of the second visual mark symbol. [5]

[0148] The ophthalmic device according to [3] or [4], characterized in that

[0149] The ophthalmologic apparatus further includes a display unit that is at least visually visible to an examiner.

[0150] The control unit displays the fatigue level estimation result on the display unit. [6]

[0152] The ophthalmic device according to [5] is characterized in that

[0153] The control unit displays the eye information acquired by the eye information acquisition unit on the display unit while gradually increasing the brightness difference by the optotype presenting means. [7]

[0155] The ophthalmic device according to any one of [3] to [6], characterized in that

[0156] The control unit sets the convergence distance indicated by the convergence angle to be shorter than the sight mark presentation distance. [8]

[0158] The ophthalmic device according to any one of [3] to [7], characterized in that

[0159] The optotype presenting mechanism includes: a left-eye display that presents the left-eye optotype and can arbitrarily change the brightness of the left-eye optotype; and a right-eye display that presents the right-eye optotype and can arbitrarily change the brightness of the right-eye optotype. [9]

[0161] The ophthalmic device according to any one of [3] to [8], characterized in that

[0162] The control unit detects the focus position of the left eye to be examined and the focus position of the right eye to be examined based on the eye information acquired by the eye information acquisition unit when detecting the gaze directions of the left eye to be examined and the right eye to be examined.

Claims

1. An ophthalmic device, characterized in that The device has an optotype presenting mechanism for presenting an optotype for the left eye to the left eye under examination and an optotype for the right eye to the right eye under examination. The left eye optotype and the right eye optotype are of the same form, The optotype presentation mechanism presents the left-eye optotype to the left eye under examination and presents the right-eye optotype to the right eye under examination, thereby expanding the brightness difference of the common part of the left-eye optotype and the right-eye optotype and maintaining the brightness difference of the remaining part of the left-eye optotype and the right-eye optotype.

2. The ophthalmic device according to claim 1, wherein The left-eye optotype and the right-eye optotype have two or more optotype symbols of the same shape, and at least one of the optotype symbols has a different parallax.

3. The ophthalmic device according to claim 2, wherein: The distance from the left eye to be examined to the left eye optotype and the distance from the right eye to the right eye optotype are used as optotype presentation distances. The position where the sight lines of the left eye under examination intersect with the sight lines of the right eye under examination is defined as the sight line intersection point, and the angle formed by the line segments connecting the left eye under examination and the right eye under examination and the sight line intersection point is defined as the convergence angle. The ophthalmic device further comprises: A convergence adjustment mechanism adjusts the convergence angle. an eye information acquisition unit that acquires eye information of the left eye to be examined and the right eye to be examined, and a control unit, configured to control the visual mark presenting mechanism, the convergence adjusting mechanism, and the eye information acquiring unit; The control unit controls the convergence adjustment mechanism to be set to an arbitrary convergence angle and controls the optotype presentation mechanism to present the left eye optotype and the right eye optotype at mutually equal optotype presentation distances, thereby expanding the brightness difference between one of the optotype symbols of the left eye optotype and the right eye optotype and maintaining the brightness difference between the other optotype symbols, detects the gaze direction of the left eye under examination and the gaze direction of the right eye under examination based on the eye information obtained by the eye information acquisition unit, calculates the timing when the fusion of the left eye under examination and the right eye under examination is destroyed, and estimates the fatigue level based on the timing when the fusion is destroyed.

4. The ophthalmic device according to claim 3, wherein The left-eye optotype and the right-eye optotype have at least a first optotype symbol of the same shape and a second optotype symbol of the same shape with a smaller convergence angle than the first optotype symbol. The control unit increases the brightness difference of the first visual mark symbol and maintains the brightness difference of the second visual mark symbol.

5. The ophthalmic device according to claim 3 or 4, characterized in that The ophthalmologic apparatus further includes a display unit that is at least visually visible to an examiner. The control unit causes the display unit to display the estimated result of the fatigue level.

6. The ophthalmic device according to claim 5, wherein: The control unit displays the eye information acquired by the eye information acquisition unit on the display unit while gradually increasing the brightness difference by the optotype presenting means.

7. The ophthalmic device according to claim 3 or 4, characterized in that The control unit sets the convergence distance indicated by the convergence angle to be shorter than the sight mark presentation distance.

8. The ophthalmic device according to claim 3 or 4, characterized in that The optotype presenting mechanism includes: a left-eye display that presents the left-eye optotype and can arbitrarily change the brightness of the left-eye optotype; and a right-eye display that presents the right-eye optotype and can arbitrarily change the brightness of the right-eye optotype.

9. The ophthalmic device according to claim 3 or 4, characterized in that The control unit detects the focus position of the left eye to be examined and the focus position of the right eye to be examined based on the eye information acquired by the eye information acquisition unit when detecting the gaze directions of the left eye to be examined and the right eye to be examined.

Images