Ophthalmological device

Abstract

Provided is an ophthalmological device with which it is possible to suppress the occurrence of double vision of subject eyes and more efficiently and more appropriately measure the eye characteristics of the subject eyes.　The ophthalmological device (1) comprises: a pair of measurement optical systems (25) that are provided correspondingly with respect to left and right subject eyes (E) and that have a visual target projection system (44) that presents a visual target to the respective subject eye at a prescribed presentation distance; focusing lenses (44e) that apply an adjustment stimulus to the subject eyes (E); a drive unit (23) that applies a convergence stimulus to the subject eyes (E); and a control unit (50). The control unit (50) controls the pair of visual target projection systems (44) so as to present a fixation target for the subject eyes (E) to fixate on while changing the presentation distance from a first examination distance to a second examination distance, and while modifying the presentation distance, controls the focusing lenses (44e) and the drive unit (23) so as to apply an adjustment stimulus to the left and right subject eyes (E) so that double vision does not occur.

Description

ophthalmology equipment

[0001] The present disclosure relates to ophthalmic devices.

[0002] Conventionally, in order to acquire the ocular characteristics of the subject's eyes, an ophthalmic apparatus has been known which includes a visual target projection system provided corresponding to each of the left and right eyes to present a visual target to each of the eyes at a predetermined test distance, and a control unit which controls the visual target projection system (see, for example, Patent Document 1). In the ophthalmic apparatus described in Patent Document 1, the control unit controls the visual target projection system to present a visual target such as an eye chart at a distance test distance for a distance test and at a near test distance for a near test.

[0003] Japanese Patent Application Laid-Open No. 2020-156664

[0004] However, this test distance is optically created by a target projection system, and only the target is presented in the subject's field of vision, so there is no sense of distance, making it difficult for the subject to determine the position of the target they should gaze at.As a result, when the target presented to the subject's eye is switched from a target presented at the distance test distance to a target presented at the near test distance, the subject's eye may not be able to adjust properly, resulting in the subject seeing two targets, or so-called diplopia.As a result, it may take a long time to measure the eye characteristics of the subject's eye, or the measurement may not be performed properly.

[0005] The present disclosure has been made in light of the above-mentioned problems, and aims to suppress the occurrence of diplopia in the subject's eye and measure the eye characteristics of the subject's eye more efficiently and appropriately.

[0006] To achieve the above object, an ophthalmologic apparatus according to the present disclosure includes: a pair of measurement optical systems for measuring ocular characteristics of the subject's eyes; an accommodation stimulus imparting unit for imparting an accommodation stimulus to the subject's eyes; a convergence stimulus imparting unit for imparting a convergence stimulus to the subject's eyes; and a control unit for controlling the subject's eye projection systems, the measurement optical systems, the accommodation stimulus imparting unit, and the convergence stimulus imparting unit. The control unit controls the pair of target projection systems to present a fixation target to be fixed on by the subject's eyes while changing the presentation distance from at least a first test distance to a second test distance, and controls the accommodation stimulus imparting unit and the convergence stimulus imparting unit to impart an accommodation stimulus and a convergence stimulus to the subject's eyes while changing the presentation distance so as not to cause diplopia.

[0007] The ophthalmologic apparatus configured in this manner can suppress the occurrence of diplopia in the subject's eye, and can measure the eye characteristics of the subject's eye more efficiently and appropriately.

[0008] 1 is a perspective view showing the overall configuration of an ophthalmic apparatus according to Example 1. FIG. 2 is a diagram showing a schematic configuration of a measurement unit of the ophthalmic apparatus according to Example 1. FIG. 3 is a diagram showing an example of a schematic configuration of a left measurement optical system of the ophthalmic apparatus according to Example 1. FIG. 4 is a block diagram showing a functional configuration of the ophthalmic apparatus according to Example 1. FIG. 5 is a diagram for explaining the relationship between the attitude of a measurement unit and a visual axis of the ophthalmic apparatus according to Example 1, showing the attitude of the measurement unit and the visual axis when a subject is caused to view infinity with binocular vision. FIG. 6 is a diagram for explaining the relationship between the attitude of the measurement unit and the visual axis of the ophthalmic apparatus according to Example 1, showing the attitude of the measurement unit and the visual axis when a subject is caused to view a predetermined distance with binocular vision. FIG. 7 is a diagram showing left and right fixation targets presented at a distance for a distance test and an image obtained by fusing the left and right fixation targets in the ophthalmic apparatus according to Example 1. FIG. 8 is a diagram showing left and right fixation targets presented at a distance between a distance test distance and a near test distance and an image obtained by fusing the left and right fixation targets in the ophthalmic apparatus according to Example 1. FIG. 9 is a diagram showing left and right fixation targets presented at a distance for a near test distance and an image obtained by fusing the left and right fixation targets in the ophthalmic apparatus according to Example 1. Fig. 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus of Example 1. Fig. 11 is a perspective view showing the overall configuration of an ophthalmologic apparatus according to a modified example.

[0009] Example 1 An ophthalmic apparatus according to Example 1 of the present disclosure will be described below with reference to FIGS. 1 to 3. The ophthalmic apparatus 1 of Example 1 is a binocular open-type ophthalmic apparatus that can acquire eye information about both eyes E simultaneously while the subject has both eyes open. The ophthalmic apparatus 1 of Example 1 can also test one eye at a time by blocking one eye or turning off the fixation target. The ophthalmic apparatus 1 is also an objective measurement device with a subjective test function that includes a target presentation function, a phoropter function, and an autorefractometer / keratometry function. Therefore, an examiner can use the ophthalmic apparatus 1 to perform any objective test and subjective test and objectively and subjectively measure the eye characteristics of the test eye.

[0010] Objective examinations include refractive power measurement (refractometry), corneal topography (keratometry), intraocular pressure measurement, fundus photography, optical coherence tomography (OCT) imaging, and measurements using OCT. Subjective examinations involve presenting a visual target to the subject, and measuring information about the subject's eye (ocular characteristics) based on the subject's response to the presented visual target. Subjective examinations include subjective refraction measurements such as distance tests, intermediate distance tests, near tests, contrast tests, and glare tests, as well as visual field tests.

[0011] [Overall Configuration of the Device] The ophthalmologic device 1 of Example 1 includes a support base 10, a measurement unit 20, an examiner controller 30, and a control unit 50. In the following, the up-down direction as seen from the subject facing the ophthalmologic device 1 is defined as the Y-axis direction. The front-to-back direction (the direction in front of and behind the subject) is defined as the Z-axis direction. The left-to-right direction perpendicular to the Y-axis and Z-axis directions is defined as the X-axis direction. The upward direction in the up-to-down direction is defined as the positive Y-axis direction. The forward direction in the front-to-back direction is defined as the positive Z-axis direction. In the left-to-right direction, the direction of the subject's right hand is defined as the positive X-axis direction.

[0012] The support base 10 has a support column 11 standing up from the floor surface and an optometry table 12 supported by the support column 11. The optometry table 12 is a platform on which devices and tools used in optometry, such as the examiner controller 30, are placed and on which the posture of the subject is supported. The optometry table 12 may be fixed in height in the Y-axis direction, or may be supported by the support column 11 so that the height in the Y-axis direction is adjustable.

[0013] The measurement unit 20 has an arm 21 and a measurement head 22. One end of the arm 21 is supported by the tip of the support column 11, and the other end extends from the support column 11 in the Z direction toward the subject, with the measurement head 22 attached to the tip. As a result, the measurement head 22 is suspended from the support column 11 via the arm 21 above the optometry table 12. The arm 21 is movable in the Y-axis direction relative to the support column 11. The arm 21 may also be movable in the X-axis direction or the Z-axis direction relative to the support column 11.

[0014] The measurement head 22 individually measures the ocular characteristics of the left eye EL, which is the subject's left eye E, and the right eye ER, which is the subject's right eye E. The measurement head 22 has a left drive unit 23L and a right drive unit 23R attached to the tip of the arm 21, a left measurement unit 24L provided below the left drive unit 23L, and a right measurement unit 24R provided below the right drive unit 23R.

[0015] The left measurement unit 24L and the right measurement unit 24R are paired to individually correspond to the left test eye EL and the right test eye ER. The left measurement unit 24L has a built-in left measurement optical system 25L that measures the ocular characteristics of the left test eye EL. The right measurement unit 24R has a built-in right measurement optical system 25R that measures the ocular characteristics of the right test eye ER. The measurement results by the left measurement unit 24L and the right measurement unit 24R are output to the control unit 50.

[0016] The left drive unit 23L is a mechanism that drives the left measurement unit 24L to move in the horizontal XZ directions and in the vertical Y direction. The left drive unit 23L is a mechanism that drives the left measurement unit 24L to rotate in the X direction, i.e., rotate around the Y axis of eyeball rotation, and rotate in the Y direction, i.e., rotate around the X axis of eyeball rotation. As shown in FIG. 2 , the left drive unit 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 drive unit 23R is a mechanism that drives the right measurement unit 24R to move horizontally in the X direction, move vertically in the Y direction, rotate in the X direction, and rotate in the Y direction. The right drive unit 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. The left drive unit 23L rotates the left measurement unit 24L around the Y-axis of rotation of the left subject eye EL, which is an axis that passes through the left eye rotation center OL (see FIG. 5, etc.) of the left subject eye EL and extends in the vertical direction. The right drive unit 23R rotates the right measurement unit 24R around the Y-axis of rotation of the right subject eye ER, which is an axis that passes through the right eye rotation center OR (see FIG. 5, etc.) of the right subject eye ER and extends in the vertical direction. In this way, the left drive unit 23L and the right drive unit 23R function as convergence stimulus imparting units, as described below.

[0017] The left drive unit 23L and the right drive unit 23R, and the left measurement unit 24L and the right measurement unit 24R are configured to be plane-symmetrical with respect to a vertical plane located midway between them in the X direction. Hereinafter, unless otherwise specified, the left drive unit 23L and the right drive unit 23R will be referred to as drive units 23, and the left measurement unit 24L and the right measurement unit 24R will be referred to as measurement units 24. The left vertical drive unit 26L and the right vertical drive unit 26R will be referred to as vertical drive unit 26. The left horizontal drive unit 27L and the right horizontal drive unit 27R will be referred to as horizontal drive unit 27. The left Y-axis rotary drive unit 28L and the right Y-axis rotary drive unit 28R will be referred to as Y-axis rotary drive unit 28. The left X-axis rotary drive unit 29L and the right X-axis rotary drive unit 29R will be referred to as X-axis rotary drive unit 29.

[0018] The vertical drive unit 26 is provided between the arm 21 and the horizontal drive unit 27 and moves the horizontal drive unit 27 in the vertical Y direction relative to the arm 21. The horizontal drive unit 27 is provided between the vertical drive unit 26 and the Y-axis rotation drive unit 28 and moves the Y-axis rotation drive unit 28 in the horizontal X and Z directions relative to the vertical drive unit 26. The vertical drive unit 26 and the horizontal drive unit 27 are configured with an actuator and a transmission mechanism. The actuator is a mechanism that generates a driving force, such as a pulse motor. The transmission mechanism is a mechanism that transmits a driving force, such as a combination of gears or a rack and pinion. The horizontal drive unit 27 can be easily configured and the horizontal movement can be easily controlled, for example, by providing a combination of an actuator and a transmission mechanism separately for the X and Z directions.

[0019] Y-axis rotation drive unit 28 is provided between horizontal drive unit 27 and X-axis rotation drive unit 29, and rotates X-axis rotation drive unit 29 about its own Y-axis rotation axis relative to horizontal drive unit 27. X-axis rotation drive unit 29 is provided between Y-axis rotation drive unit 28 and the corresponding measurement unit 24, and rotates the corresponding measurement unit 24 about its own X-axis rotation axis relative to Y-axis rotation drive unit 28.

[0020] The Y-axis rotation drive unit 28 supports the measurement unit 24 rotatably about a Y-axis rotation axis provided therein. The Y-axis rotation drive unit 28 cooperates with the horizontal drive unit 27 to rotate the measurement unit 24 about the Y-axis rotation axis while changing the supporting position of the measurement unit 24 in the XZ directions via the X-axis rotation drive unit 29. This causes the measurement unit 24 to rotate about the ocular rotation Y axis, which extends in the Y direction and passes through the left ocular rotation center OL or the right ocular rotation center OR, which is the ocular rotation center O of the corresponding subject's eye E. The ocular rotation Y axis is the axis of rotation about which the subject's eye EL rotates when it performs vergence movement. The X-axis rotation drive unit 29 also supports the measurement unit 24 rotatably about a X-axis rotation axis provided therein. The X-axis rotation drive unit 29 cooperates with the vertical drive unit 26 to rotate the measurement unit 24 about the X-axis rotation axis while changing the supporting position of the measurement unit 24 in the YZ directions. This causes the measurement unit 24 to rotate around the X-axis of rotation, which extends in the X direction and passes through the left or right center of rotation OL or OR, which is the center of rotation O of the corresponding subject's eye E. The X-axis of rotation is the axis of rotation when the subject's eye EL moves up and down.

[0021] As a modified example, the Y-axis rotation drive unit 28 and the X-axis rotation drive unit 29 may each have an actuator and a transmission mechanism, similar to the vertical drive unit 26 and the horizontal drive unit 27, and the transmission mechanism may move along an arc-shaped guide groove after receiving a driving force from the actuator. The Y-axis rotation drive unit 28 aligns the center position of the guide groove with the Y-axis of ocular rotation. That is, the Y-axis rotation axis and the Y-axis of ocular rotation are aligned. This causes the measurement unit 24 to rotate around the Y-axis of ocular rotation of the corresponding subject's eye E. The X-axis rotation drive unit 29 aligns the center position of the guide groove with the X-axis of ocular rotation. That is, the X-axis rotation axis and the X-axis of ocular rotation are aligned. This causes the measurement unit 24 to rotate around the X-axis of ocular rotation of the corresponding subject's eye E. That is, the center position of each guide groove of the Y-axis rotation drive unit 28 and the X-axis rotation drive unit 29 is aligned with the center of ocular rotation O of the corresponding subject's eye E. This allows the measuring unit 24 to rotate left and right around the eyeball rotation center O, i.e., in a rotation direction around the Y direction, and up and down, i.e., in a rotation direction around the X direction.

[0022] In this way, the left drive unit 23L and the right drive unit 23R move the left measurement unit 24L and the right measurement unit 24R individually or in conjunction with each other in the X, Y, and Z directions. Along with this movement, the left drive unit 23L rotates the left measurement unit 24L up, down, left, and right around the center of rotation O of the left subject's eye EL, and the right drive unit 23R rotates the right measurement unit 24R up, down, left, and right around the center of rotation O of the right subject's eye ER. In this way, the left drive unit 23L and the right drive unit 23R can move the left measurement unit 24L and the right measurement unit 24R to desired positions and postures relative to the corresponding subject's eyes E.

[0023] The left drive unit 23L and the right drive unit 23R can diverge or converge the left test eye EL and the right test eye ER by adjusting the positions of the left measurement unit 24L and the right measurement unit 24R. Divergence is also called divergence movement. Convergence is also called vergence movement. This allows the ophthalmic apparatus 1 to perform divergence and convergence movements on the subject. Furthermore, the ophthalmic apparatus 1 can direct the line of sight, i.e., the visual axis, of the test eye EL and the right test eye ER farther or closer by divergence and convergence. Therefore, the left drive unit 23L and the right drive unit 23R can change the posture of the left measurement unit 24L and the right measurement unit 24R in accordance with the accommodative convergence of the left and right test eyes EL and ER. Therefore, the left driving unit 23L and the right driving unit 23R function as a convergence stimulus applying unit that applies a convergence stimulus to the test eyes EL and ER. As a result, the left measuring unit 24L and the right measuring unit 24R can measure various characteristics of EL and ER of both test eyes at various test distances, from a distance test at a distance test distance to a near test distance, in a binocular vision state.

[0024] 5 shows a state in which the rotational orientations of the left and right measurement units 24L, 24R are adjusted so that the optical axes LL, LR extending from the left and right test eyes EL, ER to the left and right mirrors 24a, 24a are parallel to each other. In this state shown in FIG. 5, when the target projection systems 44 of the left and right measurement units 24L, 24R present fixation images as targets to the left and right test eyes EL, ER, the subject's visual axis can be made the same as that when looking at infinity with binocular vision.

[0025] 6 shows a state in which the rotational postures of the left and right measurement units 24L, 24R are adjusted so that the optical axes LL, LR extending from the left and right eyes EL, ER to the left and right mirrors 24a, 24a are extended toward the predetermined position M. In the state shown in FIG. 6, when the target projection systems 44 of the left and right measurement units 24L, 24R present fixation images or the like as targets to the left and right eyes EL, ER, the visual axis of the subject can be made the same as when looking at the predetermined position M with binocular vision.

[0026] In this way, the ophthalmologic apparatus 1 simultaneously changes the rotational orientations of the left and right measuring units 24L, 24R symmetrically. This allows the visual axes of the left and right test eyes EL, ER to converge or diverge, and the visual axes can be directed to the target presentation position. The target presentation position is an apparent presentation position, such as a predetermined position M, that is a predetermined distance away from the test eye E.

[0027] The measurement head 22 has a forehead rest 22a and a speaker 22b (see FIG. 4). The forehead rest 22a is disposed between the left measurement unit 24L and the right measurement unit 24R. The forehead rest 22a supports the subject's face when the subject places their forehead in contact with it during measurement of eye characteristics. That is, the subject presses their forehead against the forehead rest 22a while facing the ophthalmology table 12, stabilizing the direction and position of their face. The height position of the forehead rest 22a is adjusted by moving the arm 21 in the Y-axis direction relative to the support 11.

[0028] The speaker 22b functions as a notification unit that notifies the subject that the presentation distance of the optotype is changing, in other words, that the test distance is being switched. Under the control of the control unit 50, the speaker 22b outputs a voice message such as "Test distance is being switched" to notify the subject that the test distance is being switched, for example, while the presentation distance is changing from the first test distance to the second test distance. When the test distance switching is complete, the speaker 22b outputs a voice message such as "Test distance switching has been completed." Note that the sound output from the speaker 22b is not limited to voice, and may be music, sound effects, buzzer sounds, etc., while the presentation distance is changing.

[0029] The speaker 22b is not limited to being provided in the measurement head 22, but may be provided anywhere in the ophthalmologic apparatus 1, such as the support 11 or the optometry table 12. The notification unit is not limited to the speaker 22b, but may be a display 44a provided in the measurement optical system 25 described later. The display 44a may display messages such as "Test distance switching in progress" or "Test distance switching completed" together with the optotype to notify the subject.

[0030] The examiner's controller 30 is an information processing device that accepts input operations by the examiner and outputs control signals to the control unit 50. The examiner's controller 30 is, for example, a tablet terminal or a smartphone, and is separated from the measurement unit 20 so as to be portable by the examiner. The examiner's controller 30 may be a notebook personal computer, a desktop personal computer, or a controller dedicated to the ophthalmologic apparatus 1. The examiner's controller 30 exchanges information with the control unit 50 via wireless communication or network communication.

[0031] 1 or 4, the examiner's controller 30 includes a display unit 31, an operation-side control unit 32, input buttons 33 as an input unit, etc. The display unit 31 is made up of a touch panel display provided on the surface of the examiner's controller 30, and the input buttons 33, etc. are displayed as appropriate. The operation-side control unit 32 is made up of a microcomputer built into the examiner's controller 30. The operation-side control unit 32 controls the image displayed on the display unit 31 based on the measurement results and detection results transmitted from the control unit 50. The operation-side control unit 32 also outputs control signals to the control unit 50 in response to operations on the input buttons 33, etc.

[0032] The input buttons 33 vary in type and arrangement depending on the screen displayed on the display unit 31. For example, on the subjective test screen, the input buttons 33 include a test distance setting button and a mode selection button. The test distance setting button is a button for switching the test distance between a first test distance and a second test distance. The mode selection button is a button for selecting either a "stepwise switching mode" or a "direct switching mode." The "stepwise switching mode" is a mode in which the presentation distance is changed stepwise from the first test distance to the second test distance. The "direct switching mode" is a mode in which the first test distance is directly switched to the second test distance. This mode is set to the stepwise switching mode when the ophthalmologic apparatus 1 is shipped. By operating the mode selection button, the examiner can switch the mode to the desired mode, either the stepwise switching mode or the direct switching mode, both during initial setup and during the test. The mode switching button may also serve as the test distance setting button, and for example, the mode may be switched when the test distance setting button is pressed and held down when switching the test distance.

[0033] [Configuration of Optical System] The detailed configurations of the left measurement optical system 25L and the right measurement optical system 25R will be described below with reference to Fig. 3. The left measurement optical system 25L and the right measurement optical system 25R have the same configuration. Therefore, the following description will focus on the configuration of the left measurement optical system 25L, and the description of the configuration of the right measurement optical system 25R will be omitted.

[0034] The left measurement optical system 25L is an optical system that performs an examination by presenting any visual target (including a fixation target 60, described later) to the left test eye EL. The left measurement optical system 25L includes a Z alignment system 41, an XY alignment system 42, a keratometry system 43, a visual target projection system 44, an anterior eye observation system 45, a reflex measurement projection system 46, and a reflex measurement light-receiving system 47. The following description will be given using the fundus conjugate position P and the pupil conjugate position Q. The fundus conjugate position P is a position that is approximately optically conjugate with the fundus Ef of the left test eye EL after alignment is complete, and refers to an optically conjugate position or its vicinity. The pupil conjugate position Q is a position that is approximately optically conjugate with the pupil of the left test eye EL after alignment is complete, and refers to an optically conjugate position or its vicinity.

[0035] The Z alignment system 41 projects light onto the left test eye EL to align the anterior-posterior direction, which is the optical axis direction of the anterior eye observation system 45. In Example 1, the light used for alignment is infrared light. The Z alignment system 41 emits light from the Z alignment light source 41a, converts the light into a parallel beam using the projection lens 41b, and projects the parallel beam onto the cornea Ec of the left test eye EL through an alignment hole formed in the keratoplasty plate 43a. Based on the bright spot projected onto the cornea Ec, the control unit 50 or the examiner moves the left measurement unit 24L and the left measurement optical system 25L in the Z axis direction so that the ratio between the distance between two point images generated by the Z alignment light source 41a on the image sensor 45h, which serves as the image acquisition unit of the anterior eye observation system 45, and the diameter of the keratoplasty image falls within a predetermined range. This allows the left measurement optical system 25L to be positioned appropriately in the optical axis direction relative to the left test eye EL.

[0036] The XY alignment system 42 irradiates the left test eye EL with light for aligning the optical axis of the anterior eye observation system 45, i.e., the X-axis and Y-axis directions perpendicular to the Z-axis. In Example 1, the light for alignment is infrared light. The XY alignment system 42 has an XY alignment light source 42a and a projection lens 42b on an optical path branched from the anterior eye observation system 45 by a half mirror 45c. The XY alignment system 42 transmits the light emitted from the XY alignment light source 42a to the anterior eye observation system 45 through the projection lens 42b. The XY alignment system 42 reflects the light by the half mirror 45c and projects it onto the left test eye EL through the anterior eye observation system 45. The light reflected by the cornea Ec of the left test eye EL is guided to the image sensor 45h through the anterior eye observation system 45. The control unit 50 or the examiner moves the left measurement unit 24L (or the right measurement unit 24R) up and down or left and right based on the bright spot projected on the cornea Ec. This movement performs alignment in the Y direction, which is a direction perpendicular to the optical axis L of the anterior eye observation system 45, the up and down direction, the X direction, and the left and right direction. As a result, the left measurement optical system 25L is positioned appropriately in the X-axis direction and the Y-axis direction with respect to the left subject's eye EL. Note that the alignment method in each of 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 in which the position of the subject's eye E can be measured using a stereo camera installed in the ophthalmologic apparatus 1 may also be used.

[0037] Here, a bright spot image Br, which is an image based on light reflected by the cornea Ec, is formed superimposed on the anterior eye image E'. The control unit 50 controls the display unit 31 to display the anterior eye image E' including the bright spot image Br and the alignment mark. When performing XY alignment manually, the examiner uses the examiner controller 30 to move the left measurement optical system 25L in the X-axis and Y-axis directions. This causes the control unit 50 to move the left measurement unit 24L so as to guide the bright spot image into the alignment mark. When performing XY alignment automatically, the control unit 50 moves the left measurement unit 24L so as to cancel the displacement of the bright spot image relative to the alignment mark. This causes the control unit 50 to move the left measurement optical system 25L in the X-axis and Y-axis directions.

[0038] The keratometry system 43 projects a ring-shaped beam of infrared light onto the cornea Ec of the left subject's eye EL to measure the shape of the cornea Ec. The keratometry system 43 includes a keratometry plate 43a positioned between the objective lens 45a of the anterior segment observation system 45 and the left subject's eye EL, and a keratometry ring light source 43b provided on the rear side of the keratometry plate 43a, on the side of the objective lens 45a. The keratometry system 43 projects a ring-shaped beam of light onto the cornea Ec of the left subject's eye EL by transmitting light from the keratometry ring light source 43b through a slit in the keratometry plate 43a. A keratometry ring image, which is light reflected from the cornea Ec of the left subject's eye EL, can be detected by the image sensor 45h along with the anterior segment image E'. The control unit 50 performs known calculations based on the keratometry ring image to calculate corneal Ec shape parameters that represent the shape of the cornea Ec.

[0039] The target projection system 44 presents various targets, such as a fixation target, a target for subjective testing, and a fixation target 60 used when switching the test distance, to the left eye EL by setting the target presentation distance, i.e., the test distance, to any desired distance. The target projection system 44 includes a display 44a, a half mirror 44b, a relay lens 44c, a reflecting mirror 44d, a focusing lens 44e, a relay lens 44f, a field lens 44g, a variable cross cylinder lens (VCC) 44h, a reflecting mirror 44k, and a pinhole plate 44m. The target projection system 44 shares a dichroic mirror 46h with the reflector measurement projection system 46. The target projection system 44 shares a dichroic mirror 45b and an objective lens 45a with the anterior segment observation system 45. Furthermore, the visual target projection system 44 has at least two glare light sources 44n that irradiate glare light onto the left test eye EL, located on an optical path separate from the optical path leading to the display 44a that displays various visual targets, and at positions surrounding the optical axis.

[0040] The display 44a functions as a target presentation unit that presents various targets and is provided at a fundus conjugate position P on the optical path of the target projection system 44. The display 44a displays a fixation target or a dot-like target to which the gaze is fixed when performing an objective test or when fogging the left subject's eye EL. Alternatively, the display 44a displays a subjective test target for subjectively testing the ocular characteristics of the left subject's eye EL, a fixation target 60 (see FIGS. 7A to 7C ) used to switch the test distance, and the like. The ocular characteristics include visual acuity, distance power, near power, and the like. The display 44a can be an electroluminescence (EL) display, a liquid crystal display (LCD), or the like, and can display targets in a desired shape, configuration, and contrast (brightness).

[0041] The visual target projection system 44 reflects light from the display 44a by a half mirror 44b, passes through a relay lens 44c, reflects by a reflecting mirror 44d, and passes through a focusing lens 44e. The visual target projection system 44 passes the light through a relay lens 44f, aligns the direction of travel of the light by a field lens 44g, passes through a VCC 44h, is reflected by a reflecting mirror 44k, passes through a dichroic mirror 46h, and is reflected by a dichroic mirror 45b. The visual target projection system 44 projects the light reflected by the dichroic mirror 45b onto the fundus Ef through an objective lens 45a.

[0042] The focusing lens 44e is driven back and forth along the optical axis by a drive motor (not shown) controlled by the control unit 50. When the control unit 50 controls the focusing lens 44e to move toward the left test eye EL, the spherical power of the left test eye EL is changed to the negative diopter (-D), i.e., the refractive index is changed to the negative side. When the control unit 50 controls the focusing lens 44e to move away from the left test eye EL, the spherical power of the left test eye EL is changed to the positive diopter (+D), i.e., the refractive index is changed to the positive side (for far vision). Furthermore, by controlling the forward and backward movement of the focusing lens 44e, the control unit 50 can change the presentation distance from the left test eye EL to the presentation position of the optotype displayed on the display 44a to any value. The focusing lens 44e is configured to move in conjunction with the reflective measurement light source 46a of the reflective measurement projection system 46 and the focusing lens 47d of the reflective measurement light receiving system 47.

[0043] By moving the focusing lens 44e in this way and changing the spherical power of the subject's eye E, an accommodative stimulus is applied to the subject's eye E, causing accommodation of the crystalline lens. This allows the subject to focus on a target presented at a predetermined presentation distance. Therefore, the focusing lens 44e functions as an accommodative stimulus applying unit.

[0044] When conducting a subjective test, the control unit 50 moves the focusing lens 44e in the optical axis direction based on the results of the objective measurement, controlling the presentation distance and the spherical power of the left test eye EL. The control unit 50 then displays a predetermined optotype selected by the examiner or the like on the display 44a. This allows the predetermined optotype to be presented to the test subject at a predetermined presentation distance, relative to the left test eye EL, which has been adjusted to a predetermined spherical power. When the test subject responds to the optotype, the control unit 50 receives input of the response. For example, in the case of a visual acuity test, the control unit 50 determines the visual acuity value by repeatedly selecting and presenting the next optotype based on the subject's subjective responses to a Landolt ring or the like. Therefore, the optotype projection system 44 functions as a subjective test system.

[0045] The ophthalmologic apparatus 1 can individually present left-eye visual targets, including the left fixation target 60L, to the left test eye EL, and the presentation distance can be set to any distance. Therefore, the display 44a of the left measurement optical system 25L serves as a left display that presents left-eye visual targets, including the left fixation target 60L. The same is true for the right measurement optical system 25R, whose display 44a serves as a right display that presents right-eye visual targets, including the right fixation target 60R. This allows the test subject to fuse the visual targets displayed on the left and right displays 44a, 44a in a binocular vision state, or to view them stereoscopically. Fusion refers to combining the images reflected on the retinas of the left and right test eyes EL, ER into a single image.

[0046] The optotype projection system 44 of the ophthalmologic apparatus 1 of Example 1 presents optotypes at a first test distance and a second test distance during an examination, but is not limited to this. The optotype projection system 44 can also present optotypes at at least one third test distance different from the first test distance and the second test distance. In this case, the main controller 51 controls the optotype projection system 44 to apply accommodation stimuli and convergence stimuli to the left and right test eyes EL and ER when changing the presentation distance from the first test distance to the third test distance, when changing the presentation distance from one third test distance to another third test distance, or when changing the presentation distance from the third test distance to the second test distance.

[0047] When measuring the eye characteristics of the subject's eye E, the ophthalmic apparatus 1 first measures the eye characteristics when the subject's eye E looks at a far point, which is a far distance, i.e., performs a distance test. Based on the test results, the ophthalmic apparatus 1 measures the eye characteristics when the subject's eye E looks at a near point, which is a close distance, i.e., performs a near test. The ophthalmic apparatus 1 also measures the eye characteristics when the subject's eye E looks at a midpoint, which is an intermediate distance, as necessary. Therefore, the first test distance can be a distance test distance for a distance test of the subject's eye E. The second test distance can be a near test distance for a near test of the subject's eye E. The third test distance can be one or more test distances between the distance test distance and the near test distance. Hereinafter, the third test distance will be referred to as an "intermediate test distance."

[0048] The test distance of the target projection system 44 can be changed, for example, between 6.0 m and 25 cm. The test distance is not limited to this range and can be set to an appropriate range depending on the performance of the ophthalmologic apparatus 1. The far test distance can be set to, for example, 6 m or 5 m. The intermediate test distance can be set to, for example, 2 m. The near test distance can be set to, for example, 50 cm, 40 cm, 33 cm, 20 cm, 10 cm, etc.

[0049] The order of the tests is not limited to the distance test followed by the near test, but may be the near test followed by the distance test. In this case, the first test distance may be the near test distance, and the second test distance may be the distance test distance.

[0050] The pinhole plate 44m is provided at the pupil conjugate position Q in the visual target projection system 44, and in Example 1, it is provided between the field lens 44g and the VCC 44h. This pinhole plate 44m is formed by providing a through-hole in a plate member. The pinhole plate 44m can be inserted into and removed from the optical path of the visual target projection system 44 under the control of the control unit 50, and when inserted into the optical path, the through-hole is positioned on the optical axis. By inserting the pinhole plate 44m into the optical path in the subjective test mode, it is possible to perform a pinhole test to determine whether or not the left subject's eye EL can be corrected with glasses. Note that the pinhole plate 44m may be provided at a position on the optical path that is approximately conjugate with the pupil of the left subject's eye EL, and is not limited to the configuration of Example 1.

[0051] 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 from an anterior-segment illumination light source 48. In Example 1, the illumination light is infrared light. The anterior-segment observation system 45 passes light reflected by the anterior segment of the left eye EL through an objective lens 45a, a dichroic mirror 45b and a half mirror 45c, a relay lens 45d and a relay lens 45e, and a dichroic mirror 45f. The anterior-segment observation system 45 forms an image of the light on the imaging surface of an image sensor 45h using an imaging lens 45g. The imaging surface of the image sensor 45h is located at the pupil conjugate position Q. As a result, an anterior eye image E' onto which the keratinizing image, the light beam from the Z alignment light source 41a, and the light beam from the XY alignment light source 42a are projected, i.e., an anterior eye image E' onto which the bright spot image Br is projected, is formed on the image sensor 45h. The image sensor 45h captures images and outputs signals at a predetermined rate, and outputs the resulting video signals to the control unit 50. The control unit 50 displays a moving image of the anterior eye image E' based on the video signals output from the image sensor 45h on the display unit 31 of the examiner's controller 30. The control unit 50 can also detect the line of sight of the left eye EL based on the anterior eye image E'.

[0052] The refraction measurement projection system 46 and the refraction measurement light-receiving system 47 are objective measurement optical systems used for objective refraction measurement, that is, for measuring the objective refraction value, in other words, the refraction characteristics, as the ocular characteristics of the left subject's eye EL. The refraction measurement projection system 46 projects infrared light, which is a ring-shaped light beam for objective measurement, from the refraction measurement light source 46a onto the fundus Ef. The refraction measurement light-receiving system 47 receives the return light of this ring-shaped light beam from the left subject's eye EL. Note that the refraction measurement projection system 46 and the refraction measurement light-receiving system 47 are not limited to the configuration of Example 1, as long as they project a measurement light beam onto the fundus Ef of the left subject's eye EL and acquire the measurement light beam reflected by the fundus Ef as a measurement ring image. Another example of the configuration of the REF measurement projection system 46 and the REF measurement light receiving system 47 is one in which a point-shaped spot light is projected onto the fundus Ef as a measurement light beam, and the measurement light beam reflected by the fundus Ef, i.e., the reflected light beam, is converted into a ring-shaped light beam by passing it through a ring-shaped slit or lens, thereby obtaining a measurement ring image.

[0053] In the first embodiment, the reflex measurement light source 46a is a super luminescent diode (SLD) light source, which is a high-brightness light source with an emission diameter equal to or smaller than a predetermined size. The reflex measurement light source 46a is movable in the optical axis direction in conjunction with the focusing lens 44e and the focusing lens 47d, and is disposed at the fundus conjugate position P. The ring diaphragm 46e is a light-transmitting portion formed in a ring shape, and is disposed at the pupil conjugate position Q. The focusing lens 47d is movable in the optical axis direction in conjunction with the reflex measurement light source 46a and the focusing lens 44e. This focusing lens 47d may be a known variable-focus lens whose focal position can be changed under the control of the control unit 50. The imaging surface of the image sensor 45h in the optical system of the reflex measurement light-receiving system 47 is disposed at the fundus conjugate position P.

[0054] The reflective measurement projection system 46 causes light emitted from a reflective measurement light source 46a to pass through a relay lens 46b and be incident on the conical surface of a conical prism 46c. The reflective measurement projection system 46 deflects the light incident on the conical surface, causing it to exit from the bottom surface of the conical prism 46c, pass through a field lens 46d, and pass through the light-transmitting portion of an annular diaphragm 46e. The reflective measurement projection system 46 reflects the ring-shaped light beam that passed through the annular diaphragm 46e from the reflective surface of an aperture prism 46f, pass through a rotary prism 46g, and be reflected by a dichroic mirror 46h. The reflective measurement projection system 46 reflects the reflected light from a dichroic mirror 45b, passes through an objective lens 45a, and projects it onto the left test eye EL.

[0055] Here, it is desirable to place the conical prism 46c in a position as close as possible to the pupil conjugate position Q. The conical prism 46c may have a ring diaphragm 46e attached to its bottom surface facing the field lens 46d. In this case, for example, a light-shielding film is vapor-deposited on the bottom surface of the conical prism 46c so as to form a ring-shaped light-transmitting portion. The ring diaphragm 46e may also be located on the conical surface side of the conical prism 46c.

[0056] Furthermore, the field lens 46d may have a ring-shaped diaphragm 46e attached to its lens surface facing the left eye EL. In this case, for example, a light-shielding film is vapor-deposited on the lens surface of the field lens 46d to form a ring-shaped light-transmitting portion. The reflex measurement projection system 46 may be configured without the field lens 46d. The ring-shaped diaphragm 46e may be a diaphragm formed with a light-transmitting portion having a shape corresponding to a predetermined measurement pattern. The light-transmitting portion of this diaphragm may be formed at a position eccentric to the optical axis of the reflex measurement projection system 46. The diaphragm may also have two or more light-transmitting portions. The rotary prism 46g is used to average the light intensity distribution of the ring-shaped light beam relative to the blood vessels and diseased areas of the fundus Ef and to reduce speckle noise caused by the light source.

[0057] The REF measurement light-receiving system 47 passes the returning light of the ring-shaped light beam projected onto the fundus oculi Ef through the objective lens 45a and reflects it off the dichroic mirror 45b and dichroic mirror 46h. The REF measurement light-receiving system 47 passes the reflected returning light through the rotary prism 46g, the hole in the aperture prism 46f, and the relay lens 47a, reflects it off the reflecting mirror 47b, and passes it through the relay lens 47c and the focusing lens 47d. The REF measurement light-receiving system 47 reflects the transmitted light off the reflecting mirror 47e and the dichroic mirror 45f, and forms an image on the imaging surface of the imaging element 45h by the imaging lens 45g.

[0058] The control unit 50 is an information processing device provided below the optometry table 12. The control unit 50 comprehensively controls each part of the measurement unit 20, including the left measurement optical system 25L and the right measurement optical system 25R, based on a control signal transmitted from the examiner's controller 30. The control unit 50 also transmits to the examiner's controller 30 measurement results of the ocular characteristics of the left and right examinee's eyes EL, ER measured by the left measurement unit 24L and the right measurement unit 24R.

[0059] The control unit 50 calculates eye refractive power parameters by performing known calculations based on the output from the image sensor 45h. The eye refractive power parameters include the refractive power, spherical power, astigmatism power, and astigmatism axis angle, which are the refraction values ​​of the left and right test eyes EL and ER. The control unit 50 comprehensively controls the left measurement optical system 25L and the right measurement optical system 25R, which include the REF measurement projection system 46, the REF measurement light-receiving system 47, and the target projection system 44, as well as each component of the measurement unit 20, based on control signals transmitted from the examiner controller 30. The control unit 50 also transmits measurement results of the eye characteristics of the left test eye EL and the right test eye ER measured by the left measurement unit 24L and the right measurement unit 24R to the examiner controller 30.

[0060] [Configuration of Control Unit] The configuration of the control unit 50 will be described below with reference to Fig. 4. As shown in Fig. 4, the control unit 50 includes a main control unit 51 and a storage unit 52. The main control unit 51 includes a processor such as a CPU. The storage unit 52 includes a storage device such as a RAM, a ROM, or a hard disk.

[0061] The main controller 51 controls the light intensity change and on / off switching of the Z alignment light source 41a of the Z alignment system 41, the XY alignment light source 42a of the XY alignment system 42, and the keratometry light source 43b of the keratometry system 43. The main controller 51 also controls the on / off of the optotype displayed on the display 44a of the optotype projection system 44 and controls the switching of the optotype. The main controller 51 also controls the switching of the pinhole plate 44m of the optotype projection system 44 between insertion into and removal from the optical path. Furthermore, the main controller 51 controls the light intensity change and on / off switching of the anterior eye illumination light source 48 of the anterior eye observation system 45.

[0062] The main control unit 51 also controls the exposure time and detection sensitivity of the image sensor 45h of the anterior eye observation system 54. The main control unit 51 controls the light intensity of the reflective measurement light source 46a of the reflective measurement projection system 46 and controls the on / off switching. The main control unit 51 controls the rotation speed of the rotary prism 46g of the reflective measurement projection system 46 and controls the on / off switching of the rotation. The main control unit 51 controls the positions of the relay lenses 45d and 45e of the anterior eye observation system 45 in the optical axis direction. The main control unit 51 controls the movement of the focusing lens 44e of the target projection system 44, the reflective measurement light source 46a of the reflective measurement projection system 46, and the focusing lens 47d of the reflective measurement light receiving system 47 in the optical axis direction in an interlocked manner. The main control unit 51 also writes data to the memory unit 52 and reads data from the memory unit 52.

[0063] The memory unit 52 stores various data. The data stored in the memory unit 52 includes measurement information obtained by the keratometry system 43, measurement information obtained by the refractometry projection system 46 and the refractometry light-receiving system 47, image data acquired by the image sensor 45h, and information about the subject's eye. The subject's eye information includes information about the subject, such as the patient ID and name, and information about the left and right subject's eyes EL and ER, such as left / right eye identification information. The measurement information obtained by the keratometry system 43 is stored in the memory unit 52 when keratometry of the left and right subject's eyes EL and ER is performed. The measurement information obtained by the refractometry projection system 46 and the refractometry light-receiving system 47 is stored in the memory unit 52 when refractometry of the left and right subject's eyes EL and ER is performed. The memory unit 52 may be used as a working memory for calculating the corneal shape parameters and refractive values ​​of the left and right subject's eyes EL and ER. The storage unit 52 also stores various programs and data for operating the ophthalmologic apparatus 1. The storage unit 52 also stores parameters such as the amount of change in the amount of accommodation stimulus for providing an accommodation stimulus, the amount of change in the amount of convergence for providing a convergence stimulus, and initial addition power according to age and presentation distance.

[0064] As described above, a pair of optotype projection systems 44 are provided corresponding to the left and right eyes EL and ER to be examined. The optotype projection system 44 displays optotypes on the left display 44a and the right display 44b, respectively, and presents these optotypes at a first test distance, for example, a distance test distance, optically set by the focusing lens 44e. Then, after measurement of the eye characteristics at the first test distance is completed, the optotype projection system 44 presents optotypes at a second test distance, for example, a near test distance.

[0065] At this time, only the target is presented in the subject's field of vision, so there is no sense of distance, and it is difficult for the subject to determine at what distance the target is being viewed. For this reason, if the test distance suddenly changes from, for example, a distance test distance of 5 m to a near test distance of 40 cm, the subject's eye E cannot adjust or converge properly. As a result, the subject is unable to fuse the target with binocular vision, which can result in diplopia.

[0066] To prevent diplopia from occurring, the main controller 51 controls the optotype projection system 44 so that the presentation distance does not suddenly switch from the first test distance to the second test distance when the presentation distance is changed while the stepwise switching mode is selected. To prevent diplopia from occurring in the subject's eye E while the presentation distance is changing, the main controller 51 controls the optotype projection system 44 to apply an accommodative stimulus to the subject's eyes EL and ER according to the presentation distance. Furthermore, the main controller 51 controls the drive units 23L and 23R to rotate the left and right measuring units 24L and 24R around the ocular rotation Y axis to apply a convergence stimulus to the subject's eyes ER and ER, in response to the accommodative convergence caused in the left and right subject's eyes EL and ER by the accommodative stimulus.

[0067] More specifically, the main controller 51 controls the optotype projection system 44 to gradually change the presentation distance from the first test distance to the second test distance, and presents the optotype at each presentation distance. Along with this presentation, the main controller 51 controls the optotype projection system 44 to apply an adjustment stimulus corresponding to the changed test distance, and causes the drive units 23L and 23R to rotate the measurement units 24L and 24R about the Y axis of ocular rotation to apply a convergence stimulus. The optotype displayed on the display 44a at this time may be an optotype used to measure eye characteristics, such as an eye chart, but it is preferable to use a fixation target with a design that is easy to fuse. For example, in the example shown in Figures 7A to 7C, a fixation target with a design of a sunflower field is used. However, this is not limited thereto, and a fixation target of any desired color, pattern, design, etc. may also be used.

[0068] The presentation distance is not limited to being changed gradually, but may be changed intermittently at predetermined distance intervals. "Changing the presentation distance gradually" includes smoothly changing the presentation distance without interruption. It also includes changing the presentation distance at a predetermined distance so that the subject does not perceive the presentation distance as being changed intermittently. In contrast, "changing the presentation distance intermittently" includes, for example, changing the presentation distance from 5 m to 25 cm in stages to the predetermined presentation distance, such as 5 m → 4 m → 3 m → 2 m → 1 m → 50 cm → 30 cm → 25 cm. It also includes changing the distance in constant increments, such as by several tens of centimeters, from 5 m to 25 cm.

[0069] Furthermore, it is most preferable that the accommodative stimulus and the convergence stimulus are applied simultaneously, but the convergence stimulus may be applied after the accommodative stimulus. In this way, the accommodative stimulus is applied first to encourage accommodation in the subject's eye E, thereby encouraging accommodative convergence in the subject's eye E. Then, by rotating the left and right measuring units 24L, 24R, the subject's eye E can more easily follow the movement.

[0070] Alternatively, the accommodative stimulus may be applied after the convergence stimulus is applied. In this way, by first applying the convergence stimulus, accommodative convergence of the subject's eye E is promoted, and once appropriate convergence is achieved, the accommodative stimulus is applied to promote accommodation in the subject's eye E. Note that application of the convergence stimulus is not limited to rotation of the measurement unit 24 by the drive unit 23. The convergence stimulus can also be applied, for example, by disposing a rotary prism in the target projection system 44 and changing the prism power of this rotary prism. The convergence stimulus can also be applied by changing the display position of the fixation target 60 on the display 44a, for example.

[0071] When the presentation distance is changed intermittently, it is preferable to provide a predetermined pause time after changing the presentation distance and providing accommodation stimuli and convergence stimuli before changing to the next presentation distance. This allows for more reliable promotion of fusion for the left and right test eyes EL and ER at each presentation distance. This pause time can be, for example, 250 ms.

[0072] Furthermore, the main control unit 51 controls the movement of the focusing lens 44e to change the presentation distance and also applies an accommodative stimulus to the subject's eye E. The amount of accommodative stimulus (spherical power, unit: diopter (D)) when applying this accommodative stimulus can be calculated by the following formula.

[0073]

[0074] For example, if the presentation distance is 5 m, the amount of accommodative stimulus is −0.2 D, and if the presentation distance is 2 m, the amount of accommodative stimulus is −0.5 D. If the presentation distance is 40 cm, the amount of accommodative stimulus is −2.5 D. The control unit 50 controls the movement of the focusing lens 44 e by an amount corresponding to the amount of accommodative stimulus, thereby providing an appropriate accommodative stimulus to the subject's eye E. This accommodative stimulus adjusts the left and right subject's eyes EL and ER, allowing them to focus on the optotypes presented at each presentation distance.

[0075] The main control unit 51 then controls the drive of the left and right drive units 23L, 23R to rotate the left and right measurement units 24L, 24R around the Y axis of eyeball rotation so that the amount of convergence corresponds to the presented distance. The amount of convergence is a convergence angle, measured in prisms (Δ). This provides a convergence stimulus to the left and right test eyes EL, ER, causing the left and right test eyes EL, ER to converge at an appropriate convergence angle. The amount of convergence can be calculated based on the interpupillary distance when the test eye E is looking at infinity, the presented distance, and the distance from the corneal vertex of the test eye E to the center of rotation of the eyeball.

[0076] In this way, the presentation distance is gradually changed, and accommodation stimuli and convergence stimuli are simultaneously applied according to the presentation distance, thereby appropriately suppressing the occurrence of diplopia in the left and right test eyes EL and ER, and allowing the test subject to continue to view the left and right targets in a fused state.

[0077] Then, when the presentation distance reaches the second test distance, accommodation stimuli and convergence stimuli according to the second test distance are applied to the left and right test eyes EL and ER, causing accommodation and convergence of the lenses of the test eyes EL and ER. Thereafter, the main control unit 51 can measure the ocular characteristics of the test eye E at the second test distance in response to input instructions from the examiner.

[0078] The main controller 51 can control the target projection system 44 so that the amount of accommodation stimulus changes at a constant rate. This change in the amount of accommodation stimulus can be, for example, −0.25 D / S (−0.25 diopters per second). The main controller 51 then controls the drive of the left and right drive units 23L, 23R to apply a convergence stimulus to the left and right test eyes EL, ER so that the left and right test eyes EL, ER are in an appropriate convergence state according to the changed presentation distance and amount of accommodation stimulus. By changing the accommodation stimulus applied to the left and right test eyes EL, ER at a constant rate in this way while causing convergence, the test eyes EL, ER can more appropriately adapt to changes in presentation distance.

[0079] Alternatively, as a modified example, the main controller 51 can drive and control the left and right drive units 23L, 23R so that the amount of convergence changes at a constant rate. This rate of change in the amount of convergence can be, for example, 1.5Δ / S (1.5 prisms per second). The main controller 51 then controls the left and right target projection systems 44 so that the presentation distance and accommodative stimulus correspond to this change in the amount of convergence. This allows the subject to appropriately converge the left and right test eyes EL, ER in a more natural state. The examiner can select whether to change the presentation distance at a constant rate, the amount of accommodative stimulus at a constant rate, or the amount of convergence at a constant rate, and select or set the amount of accommodative stimulus and the amount of convergence, for example, on a subjective test screen.

[0080] The main controller 51 also controls the target projection system 44 to present the fixation target 60 at a size corresponding to the presentation distance. Figures 7A to 7C are diagrams showing fixation images of the left and right fixation targets 60L and 60R displayed on the display 44a according to the presentation distance, and an image 60F obtained by fusing the left and right fixation targets. Figure 7A shows the case where the presentation distance is the distance test distance. Figure 7B shows the case where the presentation distance is a distance between the distance test distance and the near test distance. Figure 7C shows the case where the presentation distance is the near test distance. These figures show the fixation image of the left fixation target 60L presented to the left eye EL and the fixation image of the right fixation target 60R presented to the right eye ER at each test distance, and the image 60F obtained by fusing these images.

[0081] As shown in Fig. 7A, a left fixation target 60L and a right fixation target 60R consisting of a landscape image of a sunflower field are displayed on the left and right displays 44a, 44a to allow the subject to recognize that a sunflower is located at the distance test distance. When the presentation distance is changed from the distance test distance, as shown in Fig. 7B, a left fixation target 60L and a right fixation target 60R, which are enlarged images of a part of a sunflower field, are displayed on the left and right displays 44a, 44a to allow the subject to recognize that a sunflower is located at the changed presentation distance, i.e., that the sunflower is approaching. As shown in Fig. 7C, a left fixation target 60L and a right fixation target 60R, which are enlarged images of a single sunflower, are displayed on the left and right displays 44a, 44a to allow the subject to recognize that a sunflower is located at the near test distance, i.e., that the sunflower is approaching. In this way, the target projection system 44 enlarges and presents the fixation target 60 according to the presentation distance, thereby creating the visual effect of a change in presentation distance. As a result, the subject can more clearly recognize that the presentation distance has been changed, and fusion is more appropriately promoted.

[0082] When the fixation target 60 is enlarged and displayed on the display 44a, it is not necessary to enlarge and display it at the actual size of the fixation target object, such as a sunflower, when it is positioned at each presentation distance. It is sufficient to give the subject the impression that the object is gradually approaching. Therefore, the magnification ratio of the fixation target 60 to be presented at the near test distance, i.e., the maximum magnification ratio, is determined according to the resolution of the display 44a, etc. Using this maximum magnification ratio as a reference, the magnification ratio at each presentation distance between the near test distance and the far test distance may be calculated using a known formula for calculating magnification and a substitute test distance.

[0083] 7A to 7C, the main controller 51 controls the left and right displays 44a, 44a to display the left fixation target 60L and the right fixation target 60R at the same position on the left and right, but the display is not limited to this. For example, the main controller 51 can also control the left and right displays 44a to display the left fixation target 60L and the right fixation target 60R with a parallax according to the presentation distance. The subject can see a stereoscopic image 60F in which these are stereoscopically fused.

[0084] Furthermore, as the subject ages, their accommodative power weakens, leading to so-called presbyopia. Therefore, even if an accommodative stimulus according to the presentation distance is applied, the subject's eye E is unable to properly accommodate, causing the optotype to appear blurred. This has led to a decline in accommodative power, which can be one of the causes of diplopia. When changing the presentation distance, the main controller 51 preferably controls the optotype projection system 44 so as to apply an age-appropriate initial add power to the left and right subject's eyes EL and ER. This allows for the application of an accommodative stimulus to the subject's eye E and for the accommodative stimulus to be corrected according to the subject's age. Furthermore, since the initial add power varies depending on the presentation distance, it is set to a value according to the presentation distance and age.

[0085] More specifically, for example, when the subject is under 40 years old, the accommodative power has not weakened, so there is no need to correct the subject's eye E. The main control unit 51 sets the initial add power at each presentation distance to 0D. When the subject is between 40 and 55 years old, the accommodative power is weakening, so it is necessary to provide an initial add power. When the subject is over 55 years old, the accommodative power is even weaker. Therefore, it is necessary to provide a larger initial add power than for subjects under 55 years old. The initial add power according to age and presentation distance can be calculated using a known method and is stored in the memory unit 52. The calculated initial add power may be provided as is, but it is preferable to add a slightly smaller amount of add power, which can reduce the accommodative load on the subject's eye E.

[0086] The main controller 51 corrects the amount of accommodative stimulus using the initial addition power according to the age and the presentation distance, and controls the movement of the focusing lens 44e based on the corrected amount of accommodative stimulus, thereby providing the subject's eye E with an appropriate accommodative stimulus according to the subject's age and the presentation distance, and appropriately suppressing diplopia.

[0087] Furthermore, while the presentation distance is being changed, the main control unit 51 controls the speaker 22b or the display 44a as a notification unit to notify the subject that the test distance is being switched. When the test distance switching is completed, the main control unit 51 controls the notification unit to notify the subject that the test distance switching has been completed.

[0088] Furthermore, even when the direct switching mode is selected, when the test distance is switched from the first test distance to the second test distance, the main controller 51 preferably controls the target projection system 44 to present a fixation target that is easy for the subject's eye E to fuse with accommodation, as shown in Figures 7A to 7C, preferably at a magnification rate that corresponds to the test distance. This allows the subject to recognize that the test distance has changed. By viewing this fixation target, an accommodation stimulus is applied to the subject's eye E, promoting fusion, and measurement of ocular characteristics at the changed test distance can be started in a shorter time than in the past.

[0089] An example of the operation executed by the ophthalmologic apparatus 1 of Example 1 configured as described above will be described below based on the flowchart shown in Fig. 8. It is assumed that the ophthalmologic apparatus 1 is powered on and activated, and that the control unit 50 is capable of communicating with the examiner controller 30. It is also assumed that the examiner has selected the "stepwise switching mode" by operating the selection button displayed on the display unit 31. It is also assumed that the age of the examinee is known in advance from the examinee's eye information.

[0090] The examiner prepares for the examination by having the subject face the ophthalmic apparatus 1 and place their forehead on the forehead support 22a. Then, the examiner operates the examiner controller 30 to select the distance test distance, which is the first test distance, using the test distance setting button. This causes the ophthalmic apparatus 1 to measure the ocular characteristics of the subject's eye E at the distance test distance, which is the first test distance. Then, when the examiner selects the near test distance, which is the second test distance, using the test distance setting button, the operation shown in the flowchart of FIG. 8 is started.

[0091] In step S1, the main controller 51 controls the target projection system 44 to present the fixation target 60 at a first test distance with a magnification corresponding to the first test distance, as shown in Fig. 7A. In the next step S2, the main controller 51 controls the speaker 22b to output a message informing the user that the test distance is being switched. Alternatively, the main controller 51 may control the target projection system 44 to display a message on the display 44a to notify the user.

[0092] In the next step S3, the main control unit 51 calculates the amount of vergence for adjusting the vergence. In this embodiment, the amount of vergence is changed by 1.5 prisms / S. Therefore, the initial value of the amount of vergence is 1.5 prisms, and the amount of vergence is increased by 1.5 prisms each time the process is repeated. In the next step S4, the main control unit 51 calculates the presentation distance and the amount of accommodation stimulus corresponding to the calculated amount of vergence.

[0093] In the next step S5, the main control unit 51 acquires from the storage unit 52 the initial add power corresponding to the subject's age and the presentation distance, and corrects the amount of accommodation stimulus based on the acquired initial add power. In the next step S6, the main control unit 51 controls the target projection system 44 to present the fixation target 60 at the calculated presentation distance with a magnification corresponding to this presentation distance, as shown in Figure 7B, and to apply an accommodation stimulus corresponding to the corrected amount of accommodation stimulus. As a result, the subject recognizes that the presentation distance has been changed, and the left and right test eyes EL and ER are prompted to adjust, allowing them to focus on the fixation target 60 presented at the presentation distance.

[0094] In the next step S7, the main control unit 51 controls the drive of the left and right drive units 23L, 23R in accordance with the calculated convergence amount, thereby rotating the left and right measurement units 24L, 24R. This allows the subject to appropriately converge the left and right test eyes EL, ER in accordance with the presentation distance. As a result, the occurrence of diplopia is suppressed.

[0095] In the next step S8, the main control unit 51 determines whether the presented distance has reached the second test distance, that is, the test distance that is the target for switching. When the main control unit 51 determines that the presented distance has reached the second test distance (YES), the program proceeds to step S9.

[0096] On the other hand, when the main control unit 51 determines that the presentation distance has not reached the second test distance (NO), the program returns to step S3 and steps S3 to S7 are repeated. In this way, steps S3 to S7 are repeated while the presentation distance has not reached the second test distance. This prevents diplopia from occurring, and the subject can view the fixation target 60 presented at the changed presentation distance in an appropriately fused state.

[0097] Step S9 is a process executed when the stepwise change of the presentation distance is completed. In this step S9, the main controller 51 controls the speaker 22b or the target projection system 44 to output a message by voice or display on the display 44a indicating that the test distance has been changed, thereby informing the subject. This allows the subject to recognize that the test distance has been changed and that the measurement of eye characteristics at the second test distance will begin.

[0098] 8 is now complete. After this operation is complete, the main control unit 51 controls the optotype projection system 44 to switch the presented optotype to an optotype for measuring eye characteristics, such as an eye chart, and starts measuring eye characteristics at the second test distance. Since the stepwise change in presentation distance allows the left and right test eyes EL and ER to be appropriately adjusted and converged, measurement of eye characteristics at the second test distance can be performed efficiently and appropriately.

[0099] As described above, the ophthalmologic apparatus 1 of Example 1 and the modified example includes an eye target projection system 44 that corresponds to the left and right test eyes EL, ER and presents an eye target to each test eye EL, EL at a predetermined presentation distance, an accommodation stimulus imparting unit (focusing lens 44e) that imparts an accommodation stimulus to the test eyes EL, ER, a convergence stimulus imparting unit (drive unit 23) that imparts a convergence stimulus to the test eyes EL, ER, and a control unit 50 (main control unit 51) that controls the eye target projection system 44, the accommodation stimulus imparting unit, and the convergence stimulus imparting unit. The control unit 50 controls the pair of target projection systems 44 to present fixation targets 60L, 60R to the test eyes EL, ER while changing the presentation distance from at least the first test distance to the second test distance, and also controls the accommodation stimulus applying unit and the convergence stimulus applying unit to apply accommodation stimulus and convergence stimulus to the left and right test eyes EL, ER so as to prevent diplopia from occurring while the test distance is being changed. With this configuration, the occurrence of diplopia in the test eyes is suppressed while the test distance is being changed, and the ophthalmologic apparatus 1 can measure the ocular characteristics of the test eyes more efficiently and appropriately.

[0100] The control unit 50 of the ophthalmologic apparatus 1 of each of the above-described embodiments controls the target projection system 44 to present the fixation target 60 at each presentation distance while gradually changing the presentation distance from the first test distance to the second test distance. This configuration allows smoother adjustment of the subject's eye E.

[0101] The control unit 50 of the ophthalmologic apparatus 1 of each of the above-described embodiments controls the target projection system 44 so as to present the fixation target 60 at each presentation distance while changing any one of the presentation distance, the amount of accommodation stimulus, and the amount of convergence by a fixed amount between the first test distance and the second test distance, and also controls the accommodation stimulus imparting unit and the convergence stimulus imparting unit. With this configuration, the ophthalmologic apparatus 1 can more quickly and appropriately change the presentation distance, the accommodation stimulus, or the convergence stimulus.

[0102] The ophthalmic apparatus 1 of each of the above embodiments includes a pair of measurement optical systems (measurement optical systems 25L and 25R) for measuring the ocular characteristics of the test eyes EL and ER. The convergence stimulus imparting unit includes a pair of drive units 23L and 23R that rotate the pair of measurement optical systems 25L and 25R around axes that pass through the ocular rotation centers OL and OR of the test eyes EL and ER and extend vertically. The control unit 50 controls the pair of drive units 23L and 23R to rotate the measurement optical systems 25L and 25R so that the gaze directions of the test eyes EL and ER are in a direction corresponding to the presentation distance. With this configuration, the ophthalmic apparatus 1 can position the pair of measurement optical systems 25L and 25R in a position corresponding to the accommodative convergence of the test eye E, thereby appropriately imparting a convergence stimulus to the test eyes EL and ER.

[0103] The control unit 50 of the ophthalmologic apparatus 1 in each of the above embodiments rotates the measurement optical system 25 while changing the accommodative stimulus to be applied to the subject's eye E according to the presentation distance. With this configuration, the posture of the measurement optical system 25 can be adjusted appropriately in response to the accommodative convergence caused by applying the accommodative stimulus to the subject's eye E. The control unit 50 may also control the accommodative stimulus applying unit and the pair of drive units 23 to rotate the measurement optical system 25 after changing the accommodative stimulus. With this configuration, a convergence stimulus is applied after accommodative convergence occurs in the subject's eye E due to the accommodative stimulus, allowing the subject's eye E to more appropriately adapt to changes in the presentation distance.

[0104] The accommodative stimulus applying unit of the ophthalmic apparatus 1 in each of the above-described embodiments includes an optical element (focusing lens 44e) provided in the measurement optical system 25 so as to be movable along the optical axis of the measurement optical system 25. The control unit 50 controls the measurement optical system 25 so as to move the optical element forward and backward by an amount corresponding to the accommodative stimulus to be applied to the subject's eye E. With this configuration, the ophthalmic apparatus 1 can appropriately and efficiently change the presentation distance and apply the accommodative stimulus according to the presentation distance.

[0105] The control unit 50 of the ophthalmologic apparatus 1 of each of the above-described embodiments controls the target projection system 44 so as to present the fixation target 60 at a magnification rate according to the presentation distance. This configuration allows the subject to more clearly and appropriately understand that the presentation distance is changing.

[0106] The accommodative stimulus applying unit of the ophthalmic apparatus 1 in each of the above-described embodiments corrects the accommodative stimulus applied in accordance with the presentation distance depending on the age of the subject. With this configuration, the ophthalmic apparatus 1 can apply a more appropriate accommodative stimulus to the subject's eye E depending on the subject's age, thereby more appropriately suppressing the occurrence of diplopia.

[0107] The ophthalmic device of the present disclosure has been described above based on Example 1 and modified examples, but the specific configuration is not limited to these examples, and design changes and additions are permitted as long as they do not deviate from the gist of the invention according to each claim in the scope of the claims.

[0108] The present disclosure is applied to the ophthalmic apparatus 1 of each of the above-described embodiments, which includes a pair of measurement units 24L, 24R incorporating an optotype projection system 44 and objective measurement optical systems such as a refraction measurement projection system 46 and a refraction measurement light-receiving system 47, a pair of drive units 23L, 23R that rotate the measurement units 24L, 24R around axes that pass through the centers of rotation of the test eyes EL, ER and extend in the vertical direction, and a control unit 50. In contrast, as a modified example, the present disclosure can also be applied to an ophthalmic apparatus 1A that includes an optotype presenting device 70, a refractor head 72 having a pair of optometry units (optometry units) 71L, 71R arranged in front of the left and right test eyes EL, ER so as to correspond to the left and right test eyes EL, ER, and a control unit 73 that controls them, as shown in FIG. The control unit 73 is provided in the optotype presenting device 70, and the optotype presenting device 70 and the refractor head 72 are placed on an optometry table 74, but this configuration is not limiting. The ophthalmologic apparatus 1A also includes an examiner's controller 30 that includes a display unit 31, an operation-side control unit 32, input buttons 33, etc.

[0109] The pair of optometry units 71L, 71R can be rotated in the circumferential direction (around the Y axis) by a support mechanism 75, and this rotation allows them to be inserted and removed between the subject's eye E and the optotype presenting device 70. The pair of optometry units 71L, 71R each have a left optometry optical system 76L and a right optometry optical system 76R. The left optometry optical system 76L and the right optometry optical system 76R are optical systems used to correct the visual function of the subject's eyes EL, ER, and include various optical elements such as polarizing filters, red-green filters, spherical lenses, cylindrical lenses, and prisms. Each optical element is selectively inserted and removed in front of the subject's eyes EL, ER under the control of the control unit 73.

[0110] The optotype presenting device 70 is a device that presents optotypes to the left and right test eyes EL and ER. The optotype presenting device 53 includes a housing 70a and a optotype projection system 70b housed within it. A window (opening) 70c is provided on the front (subject side) of the housing 70a, allowing the subject to view the optotype image (including the fixation target). The optotype projection system 70b is an optical system that generates the optotype image, and includes, for example, a display (optotype display unit) that displays the optotype, a convex lens system that generates a virtual image of the optotype using a light beam from the optotype, and an optical path bending mirror (all not shown) that reflects the optical path of the light beam that has passed through the convex lens system to form a virtual image of the optotype image at an image point in front of the left and right test eyes EL and ER. The display can present the same optotype image to both eyes, but can also present individual optotypes to the left and right test eyes EL and ER, such as optotypes for red-green tests, optotypes for stereopsis tests, etc. Methods for presenting individual optotype images to the left and right test eyes EL and ER in this way include, for example, arranging polarizing filters or red-green filters with different polarization directions for the left test eye EL and the right test eye ER on the display of the optotype projection system 70b, or arranging the polarizing filters that the left ophthalmological optical system 76L and the right ophthalmological optical system 76R each have in front of the test eyes EL and ER.

[0111] The ophthalmic apparatus 1A presents an optotype image in the optotype projection system 70b at least at a first examination distance and a second examination distance under the control of the control unit 73. Alternatively, the ophthalmic apparatus 1A may be configured to change the presentation distance of the optotype image projected by the optotype projection system 70b from the first examination distance to the second examination distance by selectively arranging the optical elements of the left ophthalmic optical system 76L and the right ophthalmic optical system 76R under the control of the control unit 73.

[0112] Then, while the presentation distance is being changed, the control unit 73 controls the optotype projection system 70b or the optometry optical system 76 as an accommodative stimulus imparting unit to impart accommodative stimulus to the left and right test eyes EL and ER. Specifically, while the presentation distance is gradually or intermittently changed from the first test distance to the second test distance, the control unit 73 imparts accommodative stimulus to the test eyes EL and ER by changing the power of the spherical lens placed in front of the test eye E by the optometry optical system 76 or by changing the magnification of the optotype presented by the optotype projection system 70b and displaying it, according to each presentation distance. At this time, the optometry optical system 76 arranges a prism as a convergence stimulus imparting unit in front of the test eye E to adjust the prism power and / or prism base direction of the test eye E according to the presentation distance, and a convergence stimulus is imparted to each test eye EL and ER. As a result, the modified ophthalmic device 1A can achieve the same effects as the ophthalmic device 1 of Example 1, suppressing the occurrence of diplopia in the subject's eye E and enabling the ocular characteristics of the subject's eye E to be measured more efficiently and appropriately.

[0113] The optotype presenting optical system may be housed within the main body of the ophthalmic device, or may be provided externally, separately from the main body. A separately provided optotype projection system may be mechanically moved toward or away from the main body by an appropriate drive mechanism to change the presentation distance and the amount of accommodation stimulus. Furthermore, the ophthalmic device to which the present disclosure is applicable is not limited to the ophthalmic device 1, 1A configured as in the first embodiment and the modified example described above, but may be any ophthalmic device capable of presenting optotypes to the left and right test eyes EL, ER at a plurality of predetermined presentation distances. For example, the present disclosure may be applied to a subjective ophthalmic device having an optotype projection system that presents an optotype, a corrective optical system that changes the optical properties of the optotype, and a fixed optical element fixedly disposed in the optical path of the optotype projection system for optically presenting an image of the optotype to the test eyes at a predetermined presentation distance.

[0114] In addition, with respect to the above description of the first embodiment and the modified examples, the following is further disclosed: (1) An ophthalmologic apparatus comprising: optotype projection systems provided corresponding to the left and right eyes to be examined, and presenting optotypes to each eye at a predetermined presentation distance, an accommodation stimulus application unit that applies an accommodation stimulus to the eyes to be examined, a convergence stimulus application unit that applies a convergence stimulus to the eyes to be examined, and a control unit that controls the optotype projection systems, the accommodation stimulus application unit, and the convergence stimulus application unit, wherein the control unit controls the pair of optotype projection systems to present a fixation target to be fixed on by the eyes to be examined while changing the presentation distance from at least a first test distance to a second test distance, and controls the accommodative stimulus application unit and the convergence stimulus application unit to apply the accommodation stimulus and the convergence stimulus to the eyes to be examined so as not to cause diplopia while changing the presentation distance. (2) The ophthalmologic apparatus according to (1), characterized in that the control unit controls the visual target projection system so as to present the fixation target at each presentation distance while gradually changing the presentation distance from the first test distance to the second test distance. (3) The ophthalmologic apparatus according to (1) or (2), characterized in that the control unit controls the visual target projection system so as to present the fixation target at each presentation distance while changing any one of the presentation distance, the amount of accommodation stimulus, and the amount of convergence by a constant amount between the first test distance and the second test distance, and controls the accommodation stimulus imparting unit and the convergence stimulus imparting unit. (4) The ophthalmologic apparatus according to any one of (1) to (3), further comprising a pair of measurement optical systems for measuring ocular characteristics of the subject's eye, wherein the convergence stimulus imparting unit includes a pair of drive units that rotate the pair of measurement optical systems around an axis that passes through the center of rotation of the eyeball of the subject's eye and extends in a vertical direction, and the control unit controls the pair of drive units to rotate the measurement optical systems so that the gaze direction of the subject's eye becomes a direction corresponding to the presentation distance. (5) The ophthalmologic apparatus according to (4), further comprising: a control unit that controls the accommodative stimulus imparting unit and the pair of drive units to rotate the measurement optical system while changing the accommodative stimulus to be applied to the subject's eye according to the presentation distance, or to rotate the measurement optical system after changing the accommodative stimulus.(6) The ophthalmologic apparatus according to (4) or (5), characterized in that the accommodation stimulus imparting unit includes an optical element provided in the measurement optical system so as to be movable along an optical axis of the measurement optical system, and the control unit controls the measurement optical system to advance and retract the optical element by an amount of movement corresponding to the accommodation stimulus to be imparted to the eye to be examined. (7) The ophthalmologic apparatus according to any of (1) to (3), further comprising an ophthalmologic examination optical system including a plurality of optical elements selectively arranged in front of the eye to be examined for correcting the visual function of the eye to be examined, the convergence stimulus imparting unit being an optical element included in the ophthalmologic examination optical system and comprising a prism that can change the prism power and / or prism base direction of the eye to be examined, and the control unit imparts a convergence stimulus to the eye to be examined by arranging the prism in front of the eye to set the prism power and / or prism base direction according to the presentation distance. (8) The ophthalmologic apparatus according to any one of (1) to (7), wherein the control unit controls the visual target projection system so as to present the fixation target at a magnification rate according to the presentation distance. (9) The ophthalmologic apparatus according to any one of (1) to (8), wherein the accommodative stimulus providing unit corrects the accommodative stimulus to be provided corresponding to the presentation distance according to the age of the subject. (10) The ophthalmologic apparatus according to any one of (1) to (9), comprising: a measurement unit having a measurement optical system, an image acquisition unit that acquires an image of an anterior eye segment of the subject's eye on the optical axis of the measurement optical system, and the visual target projection optical system; a drive unit that rotates the measurement unit about an axis that passes through the center of rotation of the subject's eye and extends in the vertical direction; the control unit; and the accommodative stimulus providing unit, wherein the measurement unit is suspended from the head support unit via the drive unit. (11) An ophthalmic device according to any one of (1) to (9), characterized in that it comprises an optometry section having an optometry optical system including a plurality of optical elements for correcting the visual function of the subject's eye, which is selectively positioned in front of the subject's eye; the visual target projection system; the control section; and the accommodation stimulus applying section. CROSS-REFERENCE TO RELATED APPLICATIONS

[0115] This application claims priority based on Japanese Patent Application No. 2024-146889, filed with the Japan Patent Office on August 28, 2024, the entire disclosure of which is incorporated herein by reference in its entirety.

[0116] 1: Ophthalmic apparatus 1A: Ophthalmic apparatus 23: Drive unit (vergence stimulus applying unit) 25: Measurement optical system 44e: Focusing lens (accommodation stimulus applying unit, optical element) 44: Target projection system 50: Control unit 60: Fixation target 70b: Target projection system 71: Eye examination unit (eye examination unit) 73: Control unit E: Subject's eye L: Optical axis

Claims

1. An ophthalmic device comprising: a pair of target projection systems provided corresponding to the left and right eyes to present a target to each of the eyes to be examined at a predetermined presentation distance; an accommodation stimulus application unit to apply an accommodation stimulus to the eyes to be examined; a convergence stimulus application unit to apply a convergence stimulus to the eyes to be examined; and a control unit to control the target projection systems, the accommodation stimulus application unit, and the convergence stimulus application unit, wherein the control unit controls the pair of target projection systems to present a fixation target to be fixed on by the eyes to be examined while changing the presentation distance from at least a first test distance to a second test distance, and controls the accommodation stimulus application unit and the convergence stimulus application unit to apply accommodation stimulus and convergence stimulus to the eyes to be examined so as not to cause diplopia while the presentation distance is being changed.

2. The ophthalmic device of claim 1, characterized in that the control unit controls the target projection system to present the fixation target at each presentation distance while gradually changing the presentation distance from the first test distance to the second test distance.

3. The ophthalmic device of claim 1, characterized in that the control unit controls the target projection system to present the fixation target at each presentation distance while changing any of the presentation distance, amount of accommodation stimulus, and amount of convergence by a constant amount between the first test distance and the second test distance, and also controls the accommodation stimulus imparting unit and the convergence stimulus imparting unit.

4. An ophthalmic device as described in claim 1, characterized in that it is provided with a pair of measurement optical systems for measuring the eye characteristics of the subject's eye, the convergence stimulus imparting unit includes a pair of drive units that rotate the pair of measurement optical systems around an axis that passes through the center of rotation of the eyeball of the subject's eye and extends vertically, and the control unit controls the pair of drive units to rotate the measurement optical systems so that the gaze direction of the subject's eye is in a direction corresponding to the presentation distance, thereby imparting a convergence stimulus to the subject's eye.

5. The ophthalmic device described in claim 4, characterized in that the control unit controls the accommodative stimulus imparting unit and the pair of driving units to rotate the measurement optical system while changing the accommodative stimulus applied to the test eye according to the presentation distance, or to rotate the measurement optical system after changing the accommodative stimulus.

6. An ophthalmic device as described in claim 4 or 5, characterized in that the accommodation stimulus applying unit includes an optical element arranged in the measurement optical system so as to be movable along the optical axis of the measurement optical system, and the control unit controls the measurement optical system so as to move the optical element forward and backward by an amount of movement corresponding to the accommodation stimulus applied to the subject's eye.

7. An ophthalmic device as described in claim 1, characterized in that it comprises an optometry optical system including a plurality of optical elements selectively positioned in front of the subject's eye for correcting the visual function of the subject's eye, the convergence stimulus imparting unit being an optical element included in the optometry optical system and consisting of a prism that can change the prism power and / or prism base direction of the subject's eye, and the control unit imparts a convergence stimulus to the subject's eye by positioning the prism in front of the subject's eye to set the prism power and / or prism base direction according to the presentation distance.

8. The ophthalmologic apparatus according to claim 1, wherein the control unit controls the target projection system so as to present the fixation target at a magnification rate according to the presentation distance.

9. An ophthalmic device according to claim 1, characterized in that the accommodative stimulus applying unit corrects the accommodative stimulus applied in accordance with the presentation distance according to the age of the subject.

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