Ophthalmic equipment and measurement methods

Abstract

To provide an ophthalmologic device capable of changing an examination distance and a target presentation condition as desired, and improving measurement efficiency by quickly and easily executing measurement of eye characteristics on an eye to be examined under various examination distances and presentation conditions.SOLUTION: An ophthalmologic device includes a target projection system (32) for presenting a target to an eye (E) to be examined with a predetermined examination distance and a presentation condition according to the examination distance, and a control part (26) for controlling the target projection system (32). The control part (26) controls the target projection system (32) so as to present the target with a first examination distance for a far distance examination of the eye (E) to be examined, a second examination distance for a near distance examination, and at least one third examination distance different from the first examination distance and the second examination distance.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to an ophthalmic apparatus and a measurement method.

Background Art

[0002] A technique of surgically inserting an artificial lens called an intraocular lens (IOL) into the eye is known for the treatment of cataracts and refractive correction (see, for example, Patent Document 1). In the case of cataract treatment, the lens is removed from the lens capsule, and the intraocular lens is inserted into the lens capsule. In addition to the type inserted into the lens capsule, various intraocular lenses have been developed, such as phakic intraocular lenses (phakic IOLs) that are inserted and fixed between the cornea and the iris or between the iris and the lens without removing the lens.

[0003] In order for the wearer of such an intraocular lens to perform daily life without problems, the intraocular lens can be focused on a plurality of distances such as a far point, a near point, and further a middle point. There are also intraocular lenses that can correct astigmatism. Therefore, in order to grasp whether the intraocular lens is functioning properly, it is desirable to measure the eye characteristics of the test eye at a plurality of inspection distances (distance from the test eye to the target) from the far point distance to the near point distance. In addition, in order to grasp the eye characteristics of the test eye in more detail, such as how it looks at night, a contrast test for measuring the contrast sensitivity of the test eye by changing the contrast of the target, a glare test for irradiating the test eye with light and inspecting it in a dazzling state (glare), etc., various tests are being performed (see, for example, Patent Document 2). It is also desirable to measure how it looks at various inspection distances for these tests.

[0004] Furthermore, there are other methods for correcting the refractive power of the eye being examined, such as orthokeratology, a treatment that involves inserting a special contact lens into the eye before going to sleep to change the shape of the cornea during sleep and correct myopia, and LASIK surgery, which corrects vision by irradiating the cornea with laser light. In addition, there are soft and hard contact lenses that are commonly used and have functions such as multifocal and astigmatism correction. It is desirable to be able to perform multiple tests on the ocular characteristics of the eye being examined, after correction using these methods, at various distances and using various visual targets.

[0005] However, when measuring ocular characteristics by changing the examination distance, the subject needs to move closer to or further away from the visual acuity chart displaying the visual target, which can make the examination time-consuming and cause fatigue in the subject, affecting the efficiency and accuracy of the measurement. In addition, the focal length is set differently depending on the type of intraocular lens, and contrast sensitivity may also differ. For this reason, there is a need for the development of technology that can efficiently perform various examinations by changing the examination distance and visual target presentation conditions according to the characteristics of the intraocular lens and the corrected state of the eye being examined. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-22762 [Patent Document 2] Japanese Patent Publication No. 2019-136569 [Overview of the project] [Problems that the invention aims to solve]

[0007] This disclosure is made in view of the above circumstances and aims to provide an ophthalmic device that can change the examination distance and target presentation conditions as desired, and can quickly and easily measure the ocular characteristics of the eye under examination under various examination distances and presentation conditions, thereby improving measurement efficiency. [Means for solving the problem]

[0008] To achieve the above objective, the ophthalmic apparatus of this disclosure comprises a target projection system that presents a target to the eye under examination at a predetermined examination distance and with presentation conditions corresponding to the examination distance, and a control unit that controls the target projection system. The control unit controls the target projection system to present the target at a first examination distance for distance vision testing of the eye under examination, a second examination distance for near vision testing, and at least one third examination distance different from the first and second examination distances. [Effects of the Invention]

[0009] With an ophthalmic device configured in this way, the examination distance and target presentation conditions can be changed as desired, making it possible to quickly and easily measure the ocular characteristics of the eye under examination at various examination distances and presentation conditions, thereby improving measurement efficiency. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the overall configuration of the ophthalmic device according to this embodiment. [Figure 2] This is a block diagram showing the overall configuration of the ophthalmic device according to this embodiment. [Figure 3A] This diagram illustrates the relationship between the orientation of the measuring head and the visual axis of the ophthalmic device according to this embodiment, showing the orientation of the measuring head when viewing infinity with binocular vision. [Figure 3B] This diagram illustrates the relationship between the orientation of the measuring head and the visual axis of the ophthalmic device according to this embodiment, showing the orientation of the measuring head when a predetermined distance is viewed using binocular vision. [Figure 4] This is a block diagram showing the configuration of the control system of the ophthalmic device according to this embodiment. [Figure 5] This figure shows the detailed configuration of the right eye measuring optical system of the ophthalmic device according to this embodiment. [Figure 6] This figure shows an example of a visual target (multiple contrast target) displayed on the screen at the far point distance, midpoint distance, and near point distance. [Figure 7A]It is a diagram showing a single-ratio contrast optotype, which is another example of an optotype displayed on a display. [Figure 7B] It is a diagram showing an ETDR optotype, which is another example of an optotype displayed on a display. [Figure 7C] It is a diagram showing a single-ratio contrast optotype for night inspection, which is another example of an optotype displayed on a display. [Figure 8] It is a diagram showing an example of a graph of measurement results displayed on a display surface. [Figure 9] It is a flowchart for explaining an example of the operation of an ophthalmic device according to the present embodiment. [Figure 10A] It is a diagram for explaining the display state of an optotype on the display of an ophthalmic device according to a modification example, showing a state where a mark corresponding to a tap operation or the like of a subject is superimposed on the optotype and a state where a measurement result is displayed. [Figure 10B] It is a diagram for explaining the display state of an optotype on the display of an ophthalmic device according to a modification example, showing a state where a mark corresponding to a drag operation or the like of a subject is superimposed on the optotype and a state where a measurement result is displayed. [Figure 11A] It is a diagram showing an ETDR optotype for stereoscopic vision inspection, which is an example of an optotype for stereoscopic vision inspection. [Figure 11B] It is a diagram showing an optotype for precision stereoscopic vision inspection, which is an example of an optotype for stereoscopic vision inspection. [Figure 12] It is a diagram showing an example of the display of an optotype for precision stereoscopic vision inspection on a display. The left diagram on the page shows an example of the display on a display for the left eye, and the right diagram on the page shows an example of the display on a display for the right eye. [Figure 13] It is a diagram for explaining an example of an inspection using a multiple-ratio contrast optotype and an optotype for precision stereoscopic vision inspection. [Figure 14] It is a diagram for explaining another different modification example in which the control unit determines the correctness of a response input from a subject input unit, showing a state where the subject is responding by a tap operation and a state where a measurement result based on the correctness of the response is displayed. [Figure 15]A diagram for explaining an ophthalmic device according to another embodiment of the present disclosure, which is an example of a setting screen for various parameters. [Figure 16A] A diagram for explaining an ophthalmic device according to another embodiment of the present disclosure, which is an example of a subjective examination screen before switching to an optional examination distance. [Figure 16B] A diagram for explaining an ophthalmic device according to another embodiment of the present disclosure, which is an example of a window for setting an optional examination distance. [Figure 17] A diagram for explaining an ophthalmic device according to another embodiment of the present disclosure, which is an example of a subjective examination screen when switched to an optional examination distance. [Figure 18A] A diagram for explaining an ophthalmic device according to another embodiment of the present disclosure, which is a diagram showing an output sample of measurement results. [Figure 18B] A diagram for explaining an ophthalmic device according to another embodiment of the present disclosure, which is a diagram showing another output sample of measurement results.

Mode for Carrying Out the Invention

[0011] (First Embodiment) Hereinafter, an ophthalmic device according to the first embodiment will be described. First, the overall configuration of the ophthalmic device 10 according to the first embodiment will be described with reference to FIGS. 1 to 5. The ophthalmic device 10 of the present embodiment is a binocular open type ophthalmic device capable of simultaneously measuring the characteristics of both eyes of a subject with both eyes open. In the ophthalmic device of the present embodiment, it is also possible to perform examinations on each eye separately by shielding one eye or turning off the fixation mark. Further, the ophthalmic device is not limited to the binocular open type, and the present invention can also be applied to an ophthalmic device that measures the characteristics of each eye separately.

[0012] Furthermore, the ophthalmic device 10 of this embodiment is a device for measuring the ocular characteristics of a corrected eye, such as an eye with an intraocular lens (IOL) inserted, at various examination distances (distance from the eye to the target presentation position) and under various measurement conditions (type of examination, procedure, target presentation conditions, etc.). Examples of intraocular lenses include, but are not limited to, monofocal intraocular lenses, multifocal intraocular lenses and progressive intraocular lenses (multifocal IOLs), intraocular lenses with astigmatism correction function (premium IOLs), and phakic intraocular lenses (phakic IOLs). In addition, the ophthalmic device 10 can also be used to measure the ocular characteristics of an eye after orthokeratology treatment with special contact lenses, an eye after laser treatment, an eye wearing soft contact lenses, a hard contact lens, and even an eye wearing glasses.

[0013] The ophthalmic device 10 of this embodiment can perform arbitrary subjective examinations and can also perform objective examinations. In subjective examinations, the ophthalmic device 10 presents a visual target or the like to the subject at a predetermined presentation position and obtains the examination results based on the subject's response to the visual target or the like. These subjective examinations include subjective refraction measurements such as distance vision tests, intermediate vision tests, near vision tests, contrast tests, and glare tests, as well as visual field tests. In objective examinations, the ophthalmic device 10 irradiates the subject's eye with light and measures information about the subject's eye (eye characteristics) based on the detection results of the reflected light. These objective examinations include measurements to obtain the characteristics of the subject's eye and photography to obtain an image of the subject's eye. Furthermore, objective examinations include objective refraction measurement (refractive measurement), corneal topography (keratometry), intraocular pressure measurement, fundus photography, tomographic imaging using optical coherence tomography (OCT), and measurements using OCT.

[0014] [Overall configuration of ophthalmic equipment] As shown in Figure 1, the ophthalmic apparatus 10 of this embodiment comprises a base 11, an eye examination table 12, a support column 13, an arm 14, a drive mechanism (drive unit) 15, and a pair of measuring heads 16. In the ophthalmic apparatus 10, the subject, facing the eye examination table 12, places their forehead on a forehead rest 17 provided between the two measuring heads 16, and information about the subject's eye is acquired. Throughout this specification, as shown in Figure 1, the X, Y, and Z axes are defined, with the left-right direction being the X direction, the up-down direction (vertical direction) being the Y direction, and the direction perpendicular to the X and Y directions (depth direction of the measuring heads 16) being the Z direction.

[0015] The eye examination table 12 is a table for placing the display unit / examiner controller (hereinafter simply referred to as "examiner controller") 27 and the subject controller 28, which will be described later, as well as other items used for eye examination, and is supported by a base 11. The eye examination table 12 may be supported by the base 11 in a way that allows its position (height position) in the Y direction to be adjusted.

[0016] The support column 13 is supported by a base 11 so as to extend in the Y direction at the rear end of the eye examination table 12, and an arm 14 is provided at its tip. The arm 14 suspends both measuring heads 16 on the eye examination table 12 via a drive mechanism 15 and extends in the Z direction toward the front from the support column 13. The arm 14 is movable in the Y direction relative to the support column 13. The arm 14 may also be movable in the X and Z directions relative to the support column 13. A pair of measuring heads 16 are supported at the tip of the arm 14, suspended by the drive mechanism 15.

[0017] The measuring heads 16 are provided in pairs to individually correspond to the left and right eyes of the subject, and will be referred to as the left eye measuring head 16L and the right eye measuring head 16R in the following description. The left eye measuring head 16L acquires information from the subject's left eye, and the right eye measuring head 16R acquires information from the subject's right eye. The left eye measuring head 16L and the right eye measuring head 16R are configured to be symmetrical with respect to a vertical plane located midway between them in the X direction.

[0018] Each measuring head 16 is equipped with a deflection member, a mirror 18, and information about the corresponding eye under examination is acquired through the mirror 18 by the measuring optical system 21, which will be described later.

[0019] Each measurement head 16 is equipped with a measurement optical system 21 (referred to as the right eye measurement optical system 21R and the left eye measurement optical system 21L when described individually) for acquiring ocular information of the eye being examined. The detailed configuration of the measurement optical system 21 will be described later.

[0020] Both measuring heads 16 are movably suspended by a drive mechanism 15 provided on a base portion 19 suspended from the tip of an arm 14. In this embodiment, as shown in Figure 2, the drive mechanism 15 has a left-eye drive mechanism 15L corresponding to the left-eye measuring head 16L and a right-eye drive mechanism 15R corresponding to the right-eye measuring head 16R. The left-eye drive mechanism 15L has a left-eye vertical drive unit 22L, a left-eye horizontal drive unit 23L, a left-eye X-direction rotation drive unit (left-eye horizontal rotation drive unit) 24L, and a left-eye Y-direction rotation drive unit (left-eye vertical rotation drive unit) 25L. The right eye drive mechanism 15R includes a right eye vertical drive unit 22R, a right eye horizontal drive unit 23R, a right eye X-direction rotation drive unit (right eye horizontal rotation drive unit) 24R, and a right eye Y-direction rotation drive unit (right eye vertical rotation drive unit) 25R.

[0021] The configuration of each drive unit corresponding to the left eye measuring head 16L and the configuration of each drive unit corresponding to the right eye measuring head 16R are symmetrical with respect to a vertical plane located midway between them in the X direction. Hereafter, unless otherwise specified, these will simply be referred to as the vertical drive unit 22, the horizontal drive unit 23, the X-direction rotation drive unit 24, and the Y-direction rotation drive unit 25. The same applies to other components that are provided symmetrically on the left and right sides.

[0022] As shown in Figure 2, the drive mechanism 15 is configured with the vertical drive unit 22, horizontal drive unit 23, X-direction rotation drive unit 24, and Y-direction rotation drive unit 25 arranged in that order from the top.

[0023] The vertical drive unit 22 is fixed to the base portion 19 at the tip of the arm 14 and moves the horizontal drive unit 23, the X-direction rotation drive unit 24, and the Y-direction rotation drive unit 25 relative to the arm 14 in the Y direction (vertical direction) based on a control signal from the control unit 26. The horizontal drive unit 23 is fixed to the vertical drive unit 22 and moves the X-direction rotation drive unit 24 and the Y-direction rotation drive unit 25 relative to the vertical drive unit 22 in the X direction and the Z direction (horizontal direction) based on a control signal from the control unit 26.

[0024] The vertical drive unit 22 and the horizontal drive unit 23 are configured with an actuator that generates driving force, such as a pulse motor, and a transmission mechanism that transmits driving force, such as a combination of gears or a rack and pinion. The horizontal drive unit 23 can be easily configured and horizontal movement can be easily controlled by providing separate combinations of actuators and transmission mechanisms for the X and Z directions, for example.

[0025] The X-direction rotation drive unit 24 is connected to the horizontal drive unit 23. Based on a control signal from the control unit 26, the X-direction rotation drive unit 24 rotates the corresponding measuring head 16 and Y-direction rotation drive unit 25 relative to the horizontal drive unit 23 in the X direction (horizontal direction) around a pair of left and right vertical eye rotation axes v (vL, vR shown by dashed lines for the left eye EL and right eye ER in Figure 2), which extend vertically (Y direction) through the corresponding eye rotation points O (left eye rotation point OL and right eye rotation point OR shown in Figure 2) of the eye being examined E.

[0026] The Y-direction rotation drive unit 25 is connected to the X-direction rotation drive unit 24. A measuring head 16 is suspended from this Y-direction rotation drive unit 25. Based on a control signal from the control unit 26, the Y-direction rotation drive unit 25 rotates the corresponding measuring head 16 relative to the X-direction rotation drive unit 24 in the Y-direction (vertical direction, up and down direction) around a pair of left and right horizontal eye rotation axes h (hL, hR shown by dashed lines in Figure 2 for the left eye EL and right eye ER) that extend horizontally (X-direction) through the eye rotation points O (left eye rotation point OL and right eye rotation point OR, see Figure 2) of the eye being examined E.

[0027] The X-direction rotation drive unit 24 and the Y-direction rotation drive unit 25 can be configured such that, for example, a transmission mechanism that receives driving force from an actuator moves along an arc-shaped guide groove. By aligning the center position of each guide groove with a pair of horizontal eye rotation axes h(hL,hR) and a pair of vertical eye rotation axes v(vL,vR), the X-direction rotation drive unit 24 and the Y-direction rotation drive unit 25 can rotate the measuring head 16 around the pair of horizontal eye rotation axes h(hL,hR) and the pair of vertical eye rotation axes v(vL,vR) of the eye under examination E.

[0028] Furthermore, the X-direction rotation drive unit 24 can be configured to support the Y-direction rotation drive unit 25 and the measuring head 16 so as to be rotatable around a rotation axis provided on itself, and to rotate while changing the position in which the measuring head 16 is supported in cooperation with the horizontal drive unit 23. Also, the Y-direction rotation drive unit 25 can be configured to support the measuring head 16 so as to be rotatable around a rotation axis provided on itself, and to rotate while changing the position in which the measuring head 16 is supported in cooperation with the vertical drive unit 22.

[0029] With the above configuration, the drive mechanism 15 can move each measuring head 16 individually or in conjunction with each other in the X, Y, and Z directions, and can also rotate them in the X and Y directions around the vertical eye rotation axis v and the horizontal eye rotation axis h of the eye being examined. In the ophthalmic device 10 of this embodiment, each drive unit 22 to 25 of the drive mechanism 15 is driven in response to a control signal from the control unit 26 to move and rotate each measuring head 16. Furthermore, the examiner or other person can also manually drive each drive unit 22 to 25 to move and rotate each measuring head 16.

[0030] Furthermore, the left eye X-direction rotation drive unit 24L and the right eye X-direction rotation drive unit 24R can rotate the left eye measuring head 16L and the right eye measuring head 16R in the X direction (left-right direction), thereby causing the eye under examination E to diverge (divergence movement) or converge (convergence movement). Additionally, the left eye Y-direction rotation drive unit 25L and the right eye Y-direction rotation drive unit 25R can rotate the left eye measuring head 16L and the right eye measuring head 16R in the Y direction (up-down direction), thereby directing the gaze of the eye under examination E downwards or returning it to its original position. As a result, the ophthalmic device 10 allows the subject to undergo tests for divergence and convergence movements, and to perform tests at various test distances, from distance vision tests at far points to near vision tests at near points, while maintaining binocular vision, thereby measuring various characteristics of both eyes under examination.

[0031] Figure 3A shows the state in which the rotational orientation of the left and right measuring heads 16L and 16R is adjusted so that the optical axes LL and LR, respectively, from the left and right eye EL and ER to the left and right mirrors 18L and 18R, are parallel to each other. In this state of Figure 3A, when a target (fixation image) is presented to the left and right eye EL and ER by the target projection system 32 of the left and right measuring heads 16L and 16R, the subject's visual axis can be made to be the same as the visual axis when looking at infinity in a binocular state. Figure 3B shows the state in which the rotational orientation of the left and right measuring heads 16L and 16R is adjusted so that the ends of the optical axes LL and LR, respectively, from the left and right eye EL and ER to the left and right mirrors 18L and 18R, respectively, point toward a predetermined position P. In the state shown in Figure 3B, when the target projection systems 32 of the left and right measuring heads 16L and 16R present a target (fixation image) to the left and right eyes EL and ER, the subject's visual axis can be made to be the same as when looking at a predetermined position P in a binocular state. In this way, the ophthalmic device 10 changes the visual axes of the left and right eyes EL and ER to converge or diverge by simultaneously changing the rotational orientation of the left and right measuring heads 16L and 16R symmetrically, and directs the visual axis to the target presentation position (an apparent presentation position located a predetermined examination distance from the subject eye E, for example, position P).

[0032] The ophthalmic device 10 can change the position P at which the visual target is presented by changing the rotation angle α shown in Figure 3B. The rotation angle α is the angle relative to the visual axes (parallel to each other) of each eye E when looking at infinity, as shown in Figure 3A. At infinity, the rotation angle α is 0°. The ophthalmic device 10 can also introduce parallax to the visual targets presented to the left and right eyes E in response to the change in the rotation angle α. In other words, the ophthalmic device 10 changes the position P at which the visual target is presented by changing the rotation angle α, and in response to this change, it changes the parallax applied to the visual target. As a result, the ophthalmic device 10 can present the visual target three-dimensionally to the subject in a state corresponding to the position P.

[0033] As shown in Figure 1 or Figure 2, the base 11 is equipped with a control unit 26 that comprehensively controls each part of the ophthalmic device 10. The ophthalmic device 10 also includes an examiner controller 27 used by the examiner to operate the ophthalmic device 10, and a patient controller 28 used by the patient to respond when acquiring various eye information of the eye being examined.

[0034] The examiner controller 27 is an information processing device capable of short-range communication with the control unit 26, such as a tablet terminal or smartphone. However, it is not limited to tablet terminals, etc., and the examiner controller 27 may be a notebook personal computer, a desktop personal computer, or a controller specifically for the ophthalmic device 10.

[0035] In the ophthalmic apparatus 10 of this embodiment, the examiner controller 27 is configured to be portable. The examiner controller 27 may be operated while placed on the eye examination table 12, or it may be operated while held in the examiner's hand.

[0036] The subject controller 28 includes a subject input unit 28a, such as a keyboard, mouse, joystick, touchpad, or touch panel. The subject controller 28 is connected to the control unit 26 via a wired or wireless communication path and sends input signals to the control unit 26 corresponding to the operations received by the subject input unit 28a. This subject controller 28 can also be said to be a subject input unit itself. [Measurement optical system]

[0037] The left eye measuring optical system 21L and the right eye measuring optical system 21R are each composed of a visual acuity testing device that performs visual acuity testing while switching the presented visual target, a phoropter that acquires the appropriate corrective refractive power of the eye being tested while switching and arranging corrective lenses, a refractometer or wavefront sensor for measuring refractive power, a fundus camera for capturing images of the fundus, a tomography device for capturing cross-sectional images of the retina, a specular microscope for capturing corneal endothelial images, a keratometer for measuring corneal shape, a tonometer for measuring intraocular pressure, etc., either individually or in combination.

[0038] Figure 5 shows the detailed configuration of the right eye measuring optical system 21R in the ophthalmic device of this embodiment. The mirror 18R is omitted in Figure 5. Note that the configuration of the left eye measuring optical system 21L is the same as that of the right eye measuring optical system 21R, so its explanation will be omitted, and only the right eye measuring optical system 21R will be described below.

[0039] As shown in Figure 5, the right eye measurement optical system 21R includes an observation system 31, a target projection system 32, a subjective testing system 34, a first alignment system 35, a second alignment system 36, and an example of an objective measurement optical system, which is an ocular refractive power measurement system 33 and a keratological system 37.

[0040] The observation system 31 observes the anterior segment of the eye E under examination, the target projection system 32 presents a target to the eye E under examination, and the refractive power measurement system 33 measures the refractive power. The subjective examination system 34 presents a target to the eye E under examination and shares the optical elements constituting the optical system with the target projection system 32. In this embodiment, the refractive power measurement system 33 has the function of projecting a predetermined measurement pattern onto the fundus Ef of the eye E under examination and the function of detecting the image of the measurement pattern projected onto the fundus Ef.

[0041] The first alignment system 35 and the second alignment system 36 perform alignment of the optical system with respect to the eye E under examination. The first alignment system 35 performs alignment in the direction along the optical axis of the observation system 31 (front-back direction, Z direction). The second alignment system 36 performs alignment in the direction perpendicular to the optical axis (up-down direction and left-right direction; Y direction and X direction).

[0042] The observation system 31 includes an objective lens 31a, a first dichroic filter 31b, a first half mirror 31c, a first relay lens 31d, a second dichroic filter 31e, an imaging lens 31f, and an image sensor (CCD) 31g as an image acquisition unit.

[0043] The observation system 31 projects the light beam reflected from the eye E (anterior segment) onto the image sensor 31g via the objective lens 31a and then the imaging lens 31f. As a result, an anterior segment image E' is formed on the image sensor 31g, onto which the keratling light beam, the light beam from the first alignment light source 35a, and the light beam from the second alignment light source 36a (bright spot image Br) are projected. The image sensor 31g of the observation system 31 captures this anterior segment image E'. The control unit 26 displays the anterior segment image E', etc., based on the image signal output from the image sensor 31g on the display surface 30a of the display unit 30 of the examiner controller 27.

[0044] A keratin system 37 is provided in front of the objective lens 31a. The keratin system 37 includes a keratin plate 37a and a keratin ring light source 37b. The keratin plate 37a is plate-shaped with concentric slits with respect to the optical axis of the observation system 31 and is provided near the objective lens 31a. The keratin ring light source 37b is provided in accordance with the slits of the keratin plate 37a.

[0045] In the keratography system 37, the light beam from the lit keratography light source 37b passes through the slit in the keratography plate 37a, projecting a keratography light beam (a ring-shaped target for measuring corneal curvature) onto the eye E (cornea Ec) for measuring corneal shape. The keratography light beam is reflected by the cornea Ec of the eye E and formed as an image on the image sensor 31g by the observation system 31. As a result, the image sensor 31g detects (receives) the image of the ring-shaped keratography light beam, and the control unit 26 displays the image of the measurement pattern on the display surface 30a of the display unit 30, and measures the corneal shape (radius of curvature) based on the image signal from the image sensor 31g using a well-known method.

[0046] In this embodiment, an example is shown in which a keratin plate 37a with one to three ring slits is used to measure the curvature near the center of the cornea as the corneal shape measurement system (keratin system 37). However, the corneal shape measurement system may also be a platid plate with multiple rings capable of measuring the shape of the entire cornea, or other configurations may be used, and is not limited to the configuration of this embodiment.

[0047] A first alignment system 35 is provided behind the keratin system 37 (keratin plate 37a). The first alignment system 35 has a pair of first alignment light sources 35a and a first projection lens 35b. The light beams from each first alignment light source 35a are made into parallel light beams by each first projection lens 35b, and these parallel light beams are projected onto the cornea Ec of the eye E under examination through alignment holes provided in the keratin plate 37a.

[0048] The control unit 26 or the examiner performs alignment in the direction along the optical axis (front-to-back direction) of the observation system 31 by moving the measurement head 16 in the front-to-back direction based on the bright spot (bright spot image Br) projected onto the cornea Ec. This front-to-back alignment is performed by the control unit 26 or the examiner adjusting the position of the measurement head 16 so that the ratio of the distance between the two point images from the first alignment light source 35a on the image sensor 31g to the diameter of the keratling image is within a predetermined range.

[0049] In this embodiment, the optical axis of the measuring optical system 21 is bent by the mirror 18, and at the position of the mirror image of the measuring optical system 21 with respect to the mirror 18, the optical axis of the measuring optical system 21 is configured to substantially coincide with the Z-axis. Therefore, the alignment of the measuring optical system 21 in the optical axis direction corresponds to the alignment in the Z direction.

[0050] Here, the control unit 26 may determine the amount of alignment deviation from the ratio and display this amount of alignment deviation on the display surface 30a. Note that alignment in the front-to-back direction may be performed by adjusting the position of the measurement head 16R so that the bright spot image Br from the second alignment light source 36a, which will be described later, is in focus.

[0051] Furthermore, the observation system 31 is provided with a second alignment system (parallel optical system) 36. The second alignment system 36 has a second alignment light source 36a and a second projection lens 36b, and shares a first half mirror 31c, a first dichroic filter 31b, and an objective lens 31a with the observation system 31.

[0052] The second alignment system 36 projects a light beam from the second alignment light source (point light source) 36a onto the cornea Ec of the eye E under examination as a parallel light beam via the objective lens 31a. The parallel light beam projected from the second alignment system 36 onto the cornea Ec of the eye E under examination forms a bright spot of alignment light approximately midway between the corneal apex and the center of corneal curvature. The control unit 26 or the examiner moves the measurement head 16 in the forward and backward directions based on the image (bright spot image Br) of the bright spot projected onto the cornea Ec, thereby performing alignment in directions perpendicular to the optical axis of the observation system 31 (up and down direction, left and right direction).

[0053] At this time, the control unit 26 displays the alignment mark AL, which serves as a guide for the alignment mark, on the display surface 30a, in addition to the anterior segment image E' in which the bright spot image Br is formed. The control unit 26 may also be configured to start the measurement when the alignment is completed.

[0054] The second alignment light source 36a is a light-emitting diode that emits infrared light (for example, 940 nm) in order to prevent the subject from seeing the second alignment light source 36a during the alignment operation by the second alignment system 36.

[0055] The target projection system 32 (subjective examination system 34) is an optical system that projects a target onto the fundus Ef to fixate on and cloud the eye E under examination. The target projection system 32 includes a display 32a, a second half mirror 32b, a second relay lens 32c, a first reflective mirror 32d, a first focusing lens 32e, a third relay lens 32f, a first field lens 32g, a variable cross cylinder lens (VCC) 32h, a second reflective mirror 32i, and a third dichroic filter 32j, with the first dichroic filter 31b and objective lens 31a being shared with the observation system 31. The subjective examination system 34 also includes at least two glare light sources 32k that irradiate the eye E under examination with glare light at positions surrounding the optical axis via an optical path separate from the optical path leading to the display 32a, etc.

[0056] The display 32a presents fixation targets and point targets as visual targets to fix the gaze of the eye E under examination when performing objective examinations, and also presents subjective test targets for subjectively examining the characteristics of the eye E (such as visual acuity values ​​and corrective powers (distance power, near power)). The display 32a can use electroluminescence (EL) or a liquid crystal display (LCD), and displays any image under the control of the control unit 26. The display 32a is positioned in the optical path of the target projection system 32 (subjective test system 34) at a position conjugate to the fundus Ef of the eye E under examination.

[0057] The first focusing lens 32e is driven to move forward and backward along the optical axis by a drive motor (not shown). By moving the first focusing lens 32e toward the eye E under examination, the refractive power can be shifted to the negative side. By moving the first focusing lens 32e away from the eye E under examination, the refractive power can be shifted to the positive side. Therefore, the target projection system 32 can change the examination distance from the presentation position of the target displayed on the display 32a to the eye E under examination by driving the first focusing lens 32e forward and backward. In other words, the target projection system 32 can change the presentation position of the target image and can fixate on or fogging the eye E under examination.

[0058] Furthermore, the target projection system 32 (subjective testing system 34) is equipped with a pinhole plate 32p at a position in the optical path that is approximately conjugate to the pupil of the eye E being tested (in this embodiment, between the first field lens 32g and VCC 32h). This pinhole plate 32p is formed by providing a through hole in a plate member, and under the control of the control unit 26, it is possible to insert the target projection system 32 (subjective testing system 34) into and out of the optical path, and when inserted into the optical path, the through hole is positioned on the optical axis. The pinhole plate 32p is inserted into the optical path during subjective testing, enabling a pinhole test to determine whether or not the eye E being tested can be corrected with glasses. Note that the pinhole plate 32p only needs to be positioned in the optical path that is approximately conjugate to the pupil of the eye E being tested, and is not limited to the configuration of this embodiment.

[0059] The visual targets displayed on the display 32a during subjective examinations are not particularly limited as long as they are used in optometry, and suitable examples include Landolt rings, Snellen charts, and E-charts. Furthermore, various visual targets can be used, such as visual targets consisting of characters like hiragana and katakana, pictures of animals or fingers, specific figures for binocular vision function tests such as cross targets, or visual targets consisting of landscape paintings or photographs. The visual targets may also be still images or moving images. In this embodiment, since the visual target projection system 32 is equipped with a display 32a made of an LCD or the like, visual targets of the desired shape, form and contrast can be displayed at a predetermined examination distance, enabling multifaceted and thorough optometry. In addition, since the ophthalmic device 10 is equipped with two displays 32a corresponding to the left and right eyes E under examination, visual targets that provide parallax can be displayed corresponding to a predetermined examination distance (presentation position), and stereoscopic vision tests can be performed easily and precisely with a natural orientation of the visual axis.

[0060] The refractive power measurement system 33 includes a ring-shaped light beam projection system 33A that projects a ring-shaped measurement pattern onto the fundus Ef of the eye under examination E, and a ring-shaped light beam receiving system 33B that detects (receives) the reflected light of the ring-shaped measurement pattern from the fundus Ef.

[0061] The ring-shaped light beam projection system 33A includes a reflector light source unit 33a, a fourth relay lens 33b, a pupil ring diaphragm 33c, a second field lens 33d, a perforated prism 33e, and a rotary prism 33f. The third dichroic filter 32j is shared with the target projection system 32, and the first dichroic filter 31b and objective lens 31a are shared with the observation system 31. The reflector light source unit 33a includes, for example, a reflector measurement light source 33g using an LED for reflector measurement, a collimator lens 33h, a conical prism 33i, and a ring pattern forming plate 33j, which are made able to move integrally along the optical axis of the eye refractive power measurement system 33 under the control of the control unit 26.

[0062] The ring-shaped light beam receiving system 33B includes the hole 33p of the perforated prism 33e, the third field lens 33q, the third reflecting mirror 33r, the fifth relay lens 33s, the second focusing lens 33t, and the fourth reflecting mirror 33u. The objective lens 31a, the first dichroic filter 31b, the second dichroic filter 31e, the imaging lens 31f, and the image sensor 31g are shared with the observation system 31, the third dichroic filter 32j is shared with the target projection system 32, and the rotary prism 33f and the perforated prism 33e are shared with the ring-shaped light beam projection system 33A.

[0063] Next, the operation of the refractive power measurement system 33 during refractive power measurement will be described. The control unit 26 lights up the reflector measurement light source 33g and moves the reflector light source unit 33a of the ring-shaped light beam projection system 33A and the second focusing lens 33t of the ring-shaped light beam receiving system 33B in the optical axis direction. In the ring-shaped light beam projection system 33A, the reflector light source unit 33a emits a ring-shaped measurement pattern, which is propagated through the fourth relay lens 33b, the pupil ring diaphragm 33c, and the second field lens 33d to the perforated prism 33e, where it is reflected by its reflective surface 33v and guided through the rotary prism 33f to the third dichroic filter 32j. The ring-shaped light beam projection system 33A guides its measurement pattern through the third dichroic filter 32j and the first dichroic filter 31b to the objective lens 31a, thereby projecting a ring-shaped measurement pattern onto the fundus Ef of the eye E under examination.

[0064] The ring-shaped light beam receiving system 33B focuses the ring-shaped measurement pattern formed on the fundus Ef with the objective lens 31a and propagates it through the first dichroic filter 31b, the third dichroic filter 32j, and the rotary prism 33f to the hole 33p of the perforated prism 33e. The ring-shaped light beam receiving system 33B then visualizes the measurement pattern on the image sensor 31g by passing it through the third field lens 33q, the third reflective mirror 33r, the fifth relay lens 33s, the second focusing lens 33t, the fourth reflective mirror 33u, the second dichroic filter 31e, and the imaging lens 31f. As a result, the image sensor 31g detects an image of a ring-shaped measurement pattern, and the control unit 26 displays the image of the measurement pattern on the display surface 30a. Based on the image signal from that image (image sensor 31g), the control unit 26 measures the spherical power, cylindrical power (astigmatism power), and axial angle (astigmatism axis) as refractive power of the eye using a well-known method.

[0065] Furthermore, during refractive power measurement, the control unit 26 displays a fixed fixation target on the display 32a of the target projection system 32. The light beam from the display 32a passes through the second half mirror 32b, second relay lens 32c, first reflective mirror 32d, first focusing lens 32e, third relay lens 32f, first field lens 32g, VCC 32h, second reflective mirror 32i, third dichroic filter 32j, first dichroic filter 31b, and objective lens 31a before being projected onto the fundus Ef of the eye being examined E. The examiner or the control unit 26 performs alignment with the subject fixated on the presented fixed fixation target, and based on the results of the preliminary measurement of refractive power (ref), moves the first focusing lens 32e to the far point of the eye being examined E, and then moves the first focusing lens 32e to a position where it is out of focus to create a cloudy state. As a result, the eye E under examination enters a state of accommodation rest (a state in which the lens is de-accommodated), and the refractive power of the eye is measured in this state of accommodation rest.

[0066] The configurations of the refractive power measurement system 33, the first alignment system 35, the second alignment system 36, and the keratological system 37, as well as the measurement principles of refractive power (REF), subjective examination, and corneal shape (keratology), are publicly known, so a detailed explanation will be omitted.

[0067] [Control system for ophthalmic equipment] Referring to Figure 4, the functional configuration of the control unit 26 of the ophthalmic device 10 in this embodiment will be described. As shown in Figure 4, the control unit 26 is connected to the left eye measuring optical system 21L, the right eye measuring optical system 21R, the left eye vertical drive unit 22L, left eye horizontal drive unit 23L, left eye X-direction rotation drive unit 24L, and left eye Y-direction rotation drive unit 25L of the left eye drive mechanism 15L, the right eye vertical drive unit 22R, right eye horizontal drive unit 23R, right eye X-direction rotation drive unit 24R, and right eye Y-direction rotation drive unit 25R of the right eye drive mechanism 15R, as well as the examiner controller 27, the patient controller 28, and the storage unit 29.

[0068] The examiner controller 27 is equipped with a display unit 30 consisting of a touch panel display. This display unit 30 comprises a display surface 30a on which images and the like are displayed, and a touch panel type input unit (examiner input unit) 30b superimposed on the display surface 30a. The examiner controller 27 itself can be said to be an examiner input unit. Based on the display control signal sent from the control unit 26, the examiner controller 27 displays a predetermined screen, such as the anterior segment image E' acquired by the image sensor 31g, on the display surface 30a. The examiner controller 27 is also capable of short-range communication with the control unit 26 by means of short-range wireless communication, and sends an input signal to the control unit 26 corresponding to the operation received by the input unit 30b.

[0069] The control unit 26 is equipped with internal memory 26a and is capable of short-range wireless communication with the examiner controller 27 and the patient controller 28 via communication means. Furthermore, the control unit 26 comprehensively controls the operation of the ophthalmic device 10 in response to operations on the examiner controller 27 and the patient controller 28 as appropriate by loading programs stored in the connected storage unit 29 or the built-in internal memory 26a onto, for example, RAM. In this embodiment, the internal memory 26a is composed of RAM or the like, and the storage unit 29 is composed of ROM or EEPROM or the like.

[0070] The control unit 26 functions as a measurement condition setting unit and controls the measurement optical system 21 according to the type of examination to perform measurement of ocular characteristics. Measurement conditions include, for example, the type of examination in the objective and subjective examinations described above, and the presentation conditions of the visual targets used during the examination. The control unit 26 also functions as a visual target control unit and sets predetermined presentation conditions for the visual targets presented to the subject, and controls the visual target projection system 32 based on these presentation conditions to display the visual targets on the display 32a. At this time, the control unit 26 also displays the same visual targets on the display surface 30a of the display unit 30 so that the examiner can also recognize the visual targets displayed on the display 32a. Presentation conditions include visual acuity value, examination distance, type of examination, type of visual target, magnification of the visual target, and display mode of the visual target. These presentation conditions can also be entered by the examiner during the examination via the input unit 30b of the examiner controller 27. However, in this embodiment, examination modes are set according to the type of intraocular lens, etc., and an examination mode list with appropriate presentation conditions set in advance for each examination mode is stored in the storage unit 29 in an updatable format. When the examiner selects an examination mode from the input unit 30b, the control unit 26, which receives the instruction signal resulting from this selection, retrieves the presentation conditions corresponding to the selected examination mode from the storage unit 29.

[0071] Examination modes, for example, when set for each intraocular lens, include "monofocal IOL examination mode," "multifocal IOL examination mode," "multifocal IOL examination mode," and "phakic IOL examination mode." It is desirable that these settings can be arbitrarily set or changed at facilities such as ophthalmology clinics, opticians, contact lens retailers, health checkup centers, and other facilities. This would allow for the setting of information tailored to the products and correction methods handled by each facility, the types of examinations performed at each facility, and other factors, enabling more appropriate examinations.

[0072] The visual acuity value is the value used in the examination. When presenting one target, a predetermined visual acuity value (e.g., "1.0") is set. When presenting multiple targets with different visual acuity values, a predetermined set of multiple visual acuity values ​​or ranges (e.g., "0.4~1.0", "0.4, 0.5, 0.6, ...") is set. The control unit 26 can also select and set an appropriate visual acuity value based on the refractive power measured by objective testing. In this way, by performing objective measurements in advance, the ophthalmic device 10 can efficiently and appropriately perform subjective tests such as refractive power, and the reliability of the subjective tests can be increased. Furthermore, since the required (normal) visual acuity values ​​differ when looking at distant objects and near objects, the ophthalmic device 10 or the examiner does not necessarily need to set the same visual acuity value for distance, intermediate, and near vision tests; different visual acuity values ​​can be set. Similarly, since the required visual acuity values ​​differ between monocular and binocular vision, the ophthalmic device 10 or the examiner can also set different visual acuity values ​​for monocular and binocular examinations.

[0073] The test distance is the distance at which the target is presented. This distance is set as the far point distance for measurement at the far point (e.g., 5m), the midpoint distance for measurement at the midpoint (e.g., 2m), and the near point distance for measurement at the near point (e.g., 50cm, 40cm, 33cm, 20cm, 10cm, etc.). Note that the test distance is not the actual distance between the subject and the target, but rather the apparent distance created by the target projection system 32, as if the target were presented at this distance.

[0074] Examples of subjective examinations include visual acuity tests (refractive power tests), contrast tests, night vision tests, glare tests, pinhole tests, and stereopsis tests. Examples of visual targets used for these tests include visual targets for contrast tests, glare tests, night vision tests, and stereopsis tests. Examples of visual targets include Landolt rings, Snellen charts, E-charts, letters, pictures, figures, and photographs, as mentioned above. The magnification of the visual target is increased as the test distance approaches the near point, so that it matches the depth perception the subject experiences when viewing the visual target with the naked eye. As for the display of the visual target, for example, in a contrast test, the contrast (e.g., 100%, 50%, 25%, etc.) is set. In contrast, when performing a normal visual acuity test, the contrast is set to 100%. Furthermore, when presenting multiple visual targets in contrast tests, display modes may include multi-ratio contrast targets that present multiple targets with different contrasts (see Figure 6), single-ratio contrast targets that present multiple targets with a single contrast (see Figure 7A), and ETDR targets where visual acuity values ​​change sequentially from top to bottom (see Figure 7B).

[0075] Furthermore, night vision tests are conducted to simulate vision at night, and a single-ratio contrast target for night vision tests (see Figure 7C) is used, in which the color of the target is white and the background color is black. When conducting glare tests, the contrast of the target can be set to 100%, and the glare test can be performed in conjunction with a regular visual acuity test. Alternatively, the contrast test and the glare test can be combined by presenting the contrast test target or the night vision test target and adjusting the contrast appropriately. In addition, in stereopsis tests that examine binocular vision, if parallax is to be introduced to the test eye E, the target can be presented with varying visual angles, for example, 30 seconds, 1 minute, 2 minutes, 3 minutes, 4 minutes, etc.

[0076] Here, contrast testing is a test that determines the spatial frequency characteristics (contrast sensitivity) of the visual system, including the eye being tested. Contrast is the difference in luminance (brightness) between the area where the visual target is displayed and the background on the display 32a. Contrast can be calculated by the following formula (1).

[0077] C(%)=100×(Max-Min) / (Max+Min) …(1) In equation (1) above, C is the contrast, Max is the maximum luminance (brightness) of the target area or background, and Min is the minimum luminance (brightness) of the target area or background.

[0078] Different levels of contrast result in different appearances of the presented target. Specifically, with high contrast (e.g., C=100%), the boundary between the target and the background becomes clear, and the target appears relatively sharp. As the contrast decreases (e.g., C=50%) and then to low contrast (e.g., C=25%), the boundary between the target and the background becomes increasingly indistinct, and the target appears progressively blurred.

[0079] In eyes with an intraocular lens implanted, even if there is no noticeable difference in vision during a standard visual acuity test (i.e., using a 100% contrast target) compared to the eye before implantation, vision may differ when using targets with altered contrast. Furthermore, the implantation of an intraocular lens can alter night vision, the degree of reflection and blurring of car headlights during nighttime driving, and binocular vision. These changes in vision vary depending on the type of intraocular lens. Therefore, performing contrast tests, glare tests, and stereopsis tests at various distances and with various contrast levels is extremely important and meaningful in order to enable patients to live a comfortable life (visual life) without discomfort with their vision.

[0080] Furthermore, the control unit 26 also functions as a pupil detection unit and a visual axis calculation unit, detecting the pupil centers and positions of the bright spot image Br of the left eye EL and the right eye ER. Based on these, it calculates the angle between the visual axes of the left eye EL and the right eye ER and the optical axes L of the left eye measurement head 16L and the right eye measurement head 16R. The pupil centers are detected from the anterior segment images E' of the left eye EL and the right eye ER acquired by the image sensor 31g of the observation system 31. The position of the bright spot image Br is detected as the corneal reflection, i.e., the bright spot image, of the left eye EL and the right eye ER, based on the bright spot obtained when the parallel light beam from the second alignment light source 36a of the second alignment system 36 is imaged in the left eye EL and the right eye ER. Bright spot images Br are formed as spots within the cornea Ec at a predetermined location (half the radius of curvature r of the cornea, r / 2) due to the incidence of parallel light beams.

[0081] The control unit 26 can also determine, based on the calculated visual axis (more specifically, the angle between the visual axis and the optical axis), whether the eye E being examined has strabismus or phoria, and whether the subject is properly fixating on the target. The control unit 26 can also notify the examiner and the subject by displaying the determination result on the display unit 30, or by displaying a schematic diagram of the eye E being examined with the angle value and visual axis on the display unit 30. This allows the examiner and others to recognize the presence or absence of strabismus or phoria, and whether the fixation is appropriate. Furthermore, the control unit 26 can also rotate the measurement head 16 in the X direction based on the calculated visual axis to position the measurement head 16 in line with the visual axis of the eye E being examined.

[0082] Furthermore, the control unit 26 also functions as a measurement result output unit, correlating the presentation conditions of the visual target presented to the subject with the measurement results of the eye characteristics when the visual target was presented under these conditions, and outputting them to the display unit 30, printer, etc. Specifically, for example, in the case of a contrast test, the control unit 26 graphs the relationship between the test distance, the visual acuity value (measurement result), and the contrast, as shown in Figure 8, and controls the display unit 30 to display it on the display surface 30a. Also, when a print command is input from the input unit 30b, etc., or automatically, the graph is printed out from the printer. The graph is not limited to a two-dimensional graph as shown in Figure 8, but a three-dimensional graph is also suitable, allowing the examiner and the subject to grasp the correlation between multiple items more clearly.

[0083] Furthermore, the control unit 26 controls the display unit 30 to display anterior segment images E' of the left and right eyes E being examined on the display surface 30a. By viewing these anterior segment images E', the examiner can recognize whether the examination is being performed properly. For example, if the alignment or examination is unsuccessful, the examiner can identify the cause. Possible causes of unsuccessful alignment or examination include, for example, inability to fixate, inability to use both eyes, strabismus or phoria, ptosis, inhibition, pupillary constriction, and tilted head. Therefore, by viewing the anterior segment images E' on the display unit 30, the examiner can clearly identify the cause of the unsuccessful alignment, etc. Then, they can quickly take countermeasures such as correcting the head position or alerting the subject, thereby improving the success rate of subsequent alignment and examinations.

[0084] (Example of ophthalmic device operation) An example of the operation of the ophthalmic device 10 of this embodiment, configured as described above, will be explained according to the flowchart in Figure 9. The flowchart in Figure 9 describes a case where, after performing an objective examination with binocular vision, subjective examinations are performed, including visual acuity testing, contrast testing, night vision testing, and glare testing, while changing the examination distance. Note that the operation of the ophthalmic device 10 is not limited to the following steps. It is also possible to change the order and type of examinations, and to perform examinations on one eye at a time while changing the examination distance and contrast.

[0085] First, in step S1, the control unit 26 drives the left and right X-direction rotation drive units 24 to rotate the left and right measurement heads 16 in the X direction to set the fixation target presentation position to a predetermined position. Next, in step S2, the target projection system 32 displays the fixation target (for example, a point light source target) at the center of its display 32a and presents it to the eye E being examined. In this state, the examiner instructs the subject to fixate on the fixation target.

[0086] In step S3, the control unit 26 controls the image sensors 31g of the left and right measurement optical systems 21 to start capturing images of the anterior segments of the left and right eyes E. The control unit 26 displays the anterior segment images E' of the left and right eyes E on the display surface 30a, based on the image signals output from the image sensors 31g. The control unit 26 may also display the fixation target currently presented by the display 32a on the display surface 30a.

[0087] By viewing the anterior segment image E' displayed on the display unit 30, the examiner can check for proper fixation, proper binocular vision, strabismus, heterophoria, ptosis, suppression, pupillary constriction, and head tilt. This allows the examiner to take measures such as manually opening the eyelids in case of ptosis, or alerting the subject to head tilt.

[0088] In step S4, under the control of the control unit 26, with the subject fixated on the fixation target, the first alignment system 35 performs alignment in the Z direction and the second alignment system 36 performs alignment in the X and Y directions by the operation described above.

[0089] In step S5, upon receiving (or automatically) instructions for objective examinations from the examiner via the input unit 30b, the refractive power measurement system 33, under the control of the control unit 26, performs objective examinations such as refractive power (REF) measurement and corneal shape (kerat) measurement using the keratometer system 37.

[0090] Next, in step S6, based on (or automatically) the examiner's subjective test instructions and test mode selection instructions from the input unit 30b, the control unit 26 acquires the test mode (for example, multifocal IOL mode). Then, in step S7, the control unit 26 acquires the presentation conditions corresponding to the test mode from the storage unit 29. The visual acuity value can also be set according to the degree of refractive power of the subject's eye E, based on the refractive power etc. acquired in the objective test in step S5.

[0091] Next, in step S8, in order to orient the visual axis of the eye E to the direction corresponding to the examination distance, the control unit 26 drives the left and right X-direction rotation drive units 24 according to the examination distance to rotate the left and right measuring heads 16 in the X direction. For example, in the case of an examination at the far point distance, the measuring head 16 is rotated to the position shown in Figure 3A, and the visual axis is set to infinity. In step S9, in order to present the visual target at the far point distance, the control unit 26 moves the first focusing lens 32e to a predetermined position, or to the far point in the case of an examination at the far point distance.

[0092] Next, in step S10, the control unit 26 controls the target projection system 32 to display the indicator on the display 32a with a magnification ratio corresponding to the type of target, display mode, visual acuity value, and far point distance, and also displays the same target (the magnification ratio does not have to be the same) on the display surface 30a of the display unit 30. First, the target projection system 32 presents the target with 100% contrast in order to perform a normal visual acuity test (step S11).

[0093] When the target projection system 32 displays multiple targets with different visual acuity values ​​in a table format, the examiner instructs the subject to verbally respond with the state of the target in a predetermined row or column (for example, the orientation of a Landolt ring) in order to have the subject respond to how the targets appear. Alternatively, the examiner instructs the subject to declare how many targets they can identify. In response to the subject's response, the examiner inputs the examiner's response by tapping on the display surface 30a for each target the subject was able to identify, or by clicking or dragging on the display surface 30a for rows or columns. The response signal resulting from this operation is transmitted from the input unit 30b to the control unit 26. In step S12, the control unit 26 obtains the position information of the targets that were clicked or otherwise operated based on the response signal, and obtains the measurement results such as the visual acuity value based on this position information. Note that the response input can also be performed by the subject themselves from the subject input unit 28a of the subject controller 28.

[0094] When performing a different type of examination, the ophthalmic device 10 repeats the processing in steps S10 to S12 according to the type of examination. When performing a contrast test, the control unit 26 displays multi-ratio contrast targets with varying contrasts for each column on the display 32a and display surface 30a, for example, as shown in Figure 6. The diagram on paper in Figure 6 shows the targets displayed on the display 32a when performing an examination at a far point distance. As shown in Figure 6, by simultaneously presenting multiple targets with varying visual acuity values ​​and contrasts at a single examination distance, it becomes possible to perform a rapid and efficient measurement (examination), and also improve the accuracy of the measurement.

[0095] The control unit 26 acquires the measurement results of the contrast test based on the response signal from the input unit 30b (or the subject input unit 28a). Next, when performing a night test, the control unit 26 displays a single-ratio contrast target for night testing, in which the color of the target and the background are inverted, on the display 32a and the display surface 30a at a magnification ratio corresponding to the far point distance, as shown in Figure 7C. Then, the control unit 26 acquires the measurement results of the night test based on the response signal from the input unit 30b. Next, when performing a glare test, the control unit 26 displays the single-ratio contrast target for night testing shown in Figure 7C on the display surface 30a, while flashing the glare light source 32k to elicit a response from the subject. The control unit 26 acquires the measurement results of the glare test based on the response signal from the input unit 30b.

[0096] In the next step, S13, the control unit 26 determines whether measurements have been completed at all test distances. If completed (YES), the program proceeds to step S14. If not completed (NO), the program returns to step S8 to perform a subjective test at the next test distance.

[0097] For example, when performing a test at the midpoint distance, in step S8, the control unit 26 controls the rotation of the measuring head 16 so that the visual axis is directed towards the midpoint, and in step S9, moves the first focusing lens 32e to the midpoint to present the target at the midpoint distance (e.g., 2m), and in step S10, displays the target on the display 32a or the like with a magnification corresponding to the midpoint distance (for example, in the case of a contrast test, the target shown in the diagram in the center of the page in Figure 6), and performs the visual acuity test on the subject. In step S12, the control unit 26 acquires the measurement result based on the response signal from the input unit 30b. The control unit 26 repeats these processes to perform a normal visual acuity test, contrast test, night test, glare test, and stereopsis test at the midpoint distance and acquires the measurement results for each.

[0098] Furthermore, when performing an examination at near-point distance, in step S8, the control unit 26 controls the rotation of the measuring head 16 so that the visual axis is directed towards the near point, and in step S9, moves the first focusing lens 32e to the near point to present the visual target at near-point distance (e.g., 50 cm), and in step S10, displays the visual target on the display 32a or the like with a magnification corresponding to the near-point distance (for example, the visual target shown in the lower part of Figure 6 in the case of a contrast test), and performs the subject's visual acuity test. In step S12, the control unit 26 acquires the measurement result based on the response signal from the input unit 30b. The control unit 26 repeats these processes to perform a normal visual acuity test, contrast test, night vision test, glare test, and stereopsis test at near-point distance, and acquires the measurement results for each.

[0099] Once all types of tests have been completed at all test distances, the program proceeds to step S14, where the control unit 26 graphs the measurement results and displays them on the display surface 30a, and prints them if instructed to do so. For example, in the case of a contrast test, the control unit 26 displays a graph as shown in Figure 8. After this, an objective test can be performed, allowing the examiner to confirm whether the subjective test results are appropriate. This completes the operation of the ophthalmic device 10.

[0100] (modified version) The following describes a modified version of the ophthalmic device 10 according to this embodiment. The modified ophthalmic device 10 has the same configuration and functions as the ophthalmic device 10 of this embodiment shown in Figure 1, etc. In the modified version, the control unit 26 is further configured to control the display 32a so as to display a mark corresponding to the response operation from the patient input unit 28a superimposed on the visual target.

[0101] In the modified ophthalmic device 10, during a subjective examination, the control unit 26 displays visual targets on the display 32a (and also on the display surface 30a of the examiner controller 27) according to the examination mode, as shown in the left-hand diagrams of Figures 10A and 10B. The subject then views the visual targets displayed on the display 32a and responds by tapping or clicking on individual identifiable visual targets or by dragging or swiping on identifiable areas using the subject input unit 28a, such as a touch panel or mouse. The control unit 26, having received response signals based on these response operations from the subject input unit 28a, controls the display 32a to superimpose marks (images) corresponding to the response operations onto the visual targets. In the left-hand diagram of Figure 10A, a dot (circle) mark indicating a tap operation is displayed, and in the left-hand diagram of Figure 10B, a line mark indicating a drag operation is displayed.

[0102] The control unit 26 acquires the measurement results based on the subject's response operations and, as shown in the right-hand diagram of Figures 10A and 10B, displays the targets within the subject's identifiable range with rectangular marks on the display 32a. This display allows the subject to confirm the measurement results. In addition, by displaying the marks from the subject's response operations and the rectangular marks of the measurement results on the display surface 30a of the examiner's controller 27, the examiner can also clearly understand the subject's response state and the measurement results.

[0103] Furthermore, the control unit 26 can make it easier for the subject to respond by displaying a cursor or finger icon on the display 32a based on the subject's finger position information on the touch panel or the mouse position information. Alternatively, the control unit 26 may acquire finger position information based on the captured image if a camera or the like takes a picture of the subject's finger.

[0104] As described above, even with the modified ophthalmic device 10, the examination distance and target presentation conditions can be changed as desired, allowing for quick and easy measurement of the eye characteristics of the subject's eye under various examination distances and presentation conditions, thereby improving measurement efficiency. Furthermore, by having the subject respond via the subject input unit 28a, it becomes possible to acquire eye characteristics more efficiently and quickly.

[0105] Furthermore, Figures 11A and 11B show examples of stereoscopic vision test targets that can be used with the ophthalmic device 10 of this embodiment and its modified forms. Figure 11A shows an example of an ETDR target for stereoscopic vision test, with the vertical axis representing visual acuity and the horizontal axis representing parallax. Figure 11B shows an example of a target for precision stereoscopic vision test, with the vertical axis representing parallax and the horizontal axis representing contrast and visual acuity (fixed value).

[0106] In the example in Figure 11A, for example, the target projection system 32 of the ophthalmic device 10 sets the visual angles from left to right on the paper to 30 seconds, 1 minute, 2 minutes, 3 minutes, and 4 minutes, and displays one of the five targets in each row with a corresponding parallax. In the example in Figure 11B, the contrast and visual acuity values ​​are kept constant, and for example, the target projection system 32 sets the visual angles from bottom to top on the paper to 30 seconds, 1 minute, 2 minutes, 3 minutes, and 4 minutes, and displays one of the five targets in each row with a corresponding parallax. When performing a stereopsis examination using the targets in Figures 11A and 11B, by measuring the refractive power of the eye, etc., in advance through objective testing, and setting the visual acuity values ​​of the targets, etc., in the ophthalmic device 10 or by the examiner based on these measurement results, a more appropriate and rapid subjective examination becomes possible.

[0107] Furthermore, when displaying targets for stereoscopic vision testing, the position P where the targets are presented, i.e., the testing position, can be set to a desired distance by rotating the left and right measurement heads 16 to change the rotation angle α. The subject responds to the targets that appear to pop out in three dimensions from among the displayed targets by operating the subject input unit 28a. The control unit 26 acquires the measurement result based on the response signal derived from this response operation.

[0108] Note that the visual targets in Figures 11A and 11 are superimposed images of the visual targets presented to the left and right eyes E of the test subject. The actual visual targets are displayed separately on the display 32a of the measurement head 16 for the left and right eyes. As an example, Figure 12 shows examples of the display of the visual targets for the precision stereopsis examination shown in Figure 11B on the displays 32a for the left and right eyes. The left side of Figure 12 shows an example of the visual target display on the left eye display 32a, and the right side of Figure 12 shows an example of the visual target display on the right eye display 32a. In addition, in each figure in Figure 12, the other visual target that provides parallax is indicated by a dotted line for easier understanding. Also, in the "2" column of the visual targets on the left eye display 32a in Figure 12, a dotted line is shown representing the center of the visual target. For example, visual targets that provide parallax, such as "A2" and "E2," are displayed at a position offset from the center line.

[0109] Furthermore, the superimposed image targets shown in Figures 11A and 11 can be displayed, for example, on the display unit 30 of the examiner controller 27, allowing the examiner to easily recognize the target and parallax state presented to the subject.

[0110] Next, an example of a subjective examination using multiple visual targets will be explained with reference to Figure 13. Figure 13 is a diagram illustrating an example of an examination using a multi-ratio contrast visual target and the precision stereoscopic vision test visual targets shown in Figures 11B and 12. First, the control unit 26 displays the multi-ratio contrast visual target shown in the left diagram of Figure 13 on the display 32a. The subject performs response operations to the visual targets they can identify using the subject input unit 28a.

[0111] Next, based on the measurement results with the multi-ratio contrast target, the control unit 26 displays the precision stereoscopic examination targets (see Figure 12) corresponding to the right-hand diagram in Figure 13 on the left and right displays 32a, using predetermined contrast and visual acuity values. For example, in the examination using the multi-ratio contrast target, if the visual acuity value is 0.32 and 50% contrast is distinguishable, the control unit 26 changes the parallax using this visual acuity value and contrast, and displays 25 stereoscopic examination targets on the left and right displays 32a. Therefore, there is no need for the examiner to manually select or input visual acuity values ​​or contrast, and the next stereoscopic examination can be performed immediately.

[0112] The subject then selects a visual target that appears to pop out in three dimensions using the subject input unit 28a and performs a response operation. The measurement results based on this response operation are displayed by the control unit 26 on the display 32a and the display unit 30 of the examiner controller 27. Subsequently, based on the previous measurement results, the test can be repeated by displaying visual targets for stereoscopic vision testing with changed visual acuity values ​​and contrasts. Note that the visual targets and measurement procedures explained using Figure 13 are examples and are not limited thereto. For example, the subject may perform a visual acuity test and parallax (stereoscopic vision) test using the ETDR visual target for stereoscopic vision testing shown in Figure 11A, and based on these measurement results, perform a more detailed stereoscopic vision test using the precision stereoscopic vision test visual target shown in Figure 11B. The control unit 26 also graphs the measurement results and displays them on the display surface 30a, and prints them if a print instruction is given.

[0113] Furthermore, as explained using Figures 10A and 10B, in a method where the subject responds by self-reporting an identifiable target, the reliability of the response becomes an issue and can affect the measurement results. To avoid this, as another different modification, the control unit 26 is configured to determine the correctness of the subject's response in the self-report test. Specifically, as shown in the left-hand diagram of Figure 14, the control unit 26 displays a target according to the test mode on the display 32a (and also on the display surface 30a of the examiner controller 27). In the example in Figure 14, a multi-ratio contrast target consisting of Landolt rings is displayed. Upon seeing this display, the subject responds by tapping near the opening of each Landolt ring on the display 32a. In the left-hand diagram of Figure 14, the position tapped by the subject is indicated by a checkmark, but a marker indicating this tapped position may also be superimposed on the target. Alternatively, the subject may respond by indicating the direction of the opening with a joystick or the like. Alternatively, the examiner may initiate a response operation from the input unit 30b of the examiner controller 27 based on the subject's verbal response.

[0114] The control unit 26 then determines whether the subject's response is correct or incorrect based on the response signals from the subject input unit 28a and input unit 30b, and acquires the measurement result based on this determination. This improves the reliability of the subject's response in the subjective test, resulting in more objective and accurate measurement results. The control unit 26 may also refer to the measurement results from objective measurements when determining whether the response is correct or incorrect. Furthermore, as shown in the right-hand diagram of Figure 14, the control unit 26 can be configured to display only the correctly answered targets on the display 32a with a rectangular mark, allowing the subject and examiner to easily confirm the correct / incorrect determination results and measurement results.

[0115] (Second Embodiment) The following describes the ophthalmic device 10 according to the second embodiment and the measurement method using this ophthalmic device 10. The ophthalmic device 10 of this second embodiment has the same basic configuration (hardware configuration and functional configuration) as the ophthalmic device 10 of the first embodiment shown in Figures 1 to 5, but the measurement method (measurement program) executed by the control unit 26 differs from that of the first embodiment. In addition, the ophthalmic device 10 of this second embodiment allows setting a "prescription mode" that switches to an optional examination distance for examination, in addition to the examination mode described in the first embodiment.

[0116] The following describes "visual acuity confirmation at an optional testing distance" as an example of a measurement method performed by the ophthalmic device 10, with reference to Figures 15 to 18A. Figures 15 to 17 are examples of screens displayed on the display surface 30a of the display unit 30 of the examiner controller 27. Figure 15 is the setting screen 40 for various parameters. Figure 16A is the subjective examination screen 41 before switching to the optional testing distance. Figure 16B is the window 42 for setting the optional testing distance. Figure 17 is the subjective examination screen 41 when switching to the optional testing distance. A touch panel input unit 30b is provided on the display surface 30a of this display unit 30, allowing the examiner or other user to input numerical values ​​and instructions. Figures 18A and 18B are examples of output samples of measurement results.

[0117] "Optional examination distance" refers to a third examination distance that the user can arbitrarily select and set, in addition to the first examination distance (distance vision) for basic distance vision testing (hereinafter referred to as "distance vision examination distance") and the second examination distance (near vision) for near vision testing (hereinafter referred to as "near vision examination distance"). In this embodiment, as shown in Figure 15, the user can arbitrarily select at least one (for example, three) arbitrary examination distances as optional examination distances (third examination distances) on the setting screen 40. In this embodiment, examination distances of 1.0m or more are treated as distance vision examination distances (distance vision) and are displayed as "m" on the display surface 30a. Conversely, examination distances of less than 1.0m are treated as near vision examination distances (near vision) and are displayed as "cm" on the display surface 30a.

[0118] Figure 15 shows the settings screen 40 when the "Subjective Settings" bar 40g on the menu bar 40f is pressed. This settings screen 40 has a long-distance inspection distance area 40a, a close-distance inspection distance area 40b, and first, second, and third optional inspection distance areas 40c, 40d, and 40e, allowing the user to register three optional inspection distances in addition to the long-distance and close-distance inspection distances.

[0119] In the first to third optional inspection distance areas 40c to 40e, the user can register any of the following setting values. Note that "-" below means "not set", and this "-" is set as the default setting value (default) at the time of shipment for the first to third optional inspection distance areas 40c to 40e. The control unit 26 stores the optional inspection distance set by the inspector in the storage unit 29. The setting values ​​are as follows. When the unit is "meter", the set values ​​are "-, 6.0, 5.5, 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.0". When the unit is "cm", the set values ​​are "-, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 33, 30, 25". When the unit is "feet", the set values ​​will be "-, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3". If the unit is "inch," the set values ​​will be "-, 34, 32, 30, 28, 26, 24, 22, 20, 18, 16, 14, 13, 12, 10."

[0120] [Visual acuity check at optional testing distance] The following describes the procedure for the examiner to test the subject's visual acuity at any optional testing distance. After objectively measuring the subject's visual acuity through objective testing, the examiner can switch to subjective testing, having the subject perform subjective testing at the usual distance and near vision testing distances, and then performing subjective testing at an optional testing distance in order to prescribe corrective lenses for the subject's eye E.

[0121] To enable subjective examination at this optional testing distance, this embodiment allows the examiner to set the testing distance within a range of 6m to 25cm (20 feet to 10 inches). By utilizing this function, the ophthalmic device 10 of this embodiment can adjust the subject's sphericality and record visual acuity values ​​at three optional testing distances, in addition to the basic "distance testing distance (far vision)" and "near vision testing distance (near vision)" tests. The procedure for changing the optional testing distance will be explained below.

[0122] [Changing the optional test distance on the self-assessment screen] The default "Optional Exam Distance" set on settings screen 40 can be changed by the user for each subject during the self-examination. The "Optional Exam Distance" changed here will be applied until the user returns to the subject information input screen (not shown) to perform the examination on another subject.

[0123] Figure 16A shows an example of the subjective examination screen 41. The main data area 41e in this subjective examination screen 41 displays the refractive correction values ​​currently set in each part of the measurement head 16 and the measured visual acuity values ​​(hereinafter, these values ​​are referred to as "main data"). For example, the sphericality (S), astigmatism power (C), astigmatism axis (A), and add power (ADD) of the eye E being examined are displayed. When the examination switches from an objective examination to a subjective examination, the main data area 41e is set to, for example, the values ​​obtained in the objective examination.

[0124] In self-examination tests, users can increase or decrease these values ​​by touching the display surface 30a (input section 30b), however, some values ​​cannot be changed depending on the test distance. Table 1 below shows whether each value can be changed and its retention (recording) status for each test distance. In Table 1 below, changing a value marked with "*" will change that value for all test distances in conjunction.

[0125] [Table 1]

[0126] Then, on this self-awareness test screen 41, the examiner can change the optional test distance using the following procedure. (1) First, when the examiner presses (tap) the hamburger menu 41a on the subjective examination screen 41, the control unit 26 displays menu 41b on the subjective examination screen 41. (2) From the displayed menu 41b, the examiner presses the "Optional exam distance setting" button 41c. (3) Upon receiving this input, the control unit 26 displays a window 42 for setting the "Optional exam distance" as shown in Figure 16B.

[0127] The examiner can change the three optional inspection distances (optional inspection distances 1, 2, and 3) by changing the values ​​in the first, second, and third optional inspection distance change areas 42a, 42b, and 42c of window 42. In the example in Figure 16B, the examiner set optional inspection distance 1 to 2.0m, which is closer than the normal long-distance inspection distance of 5.0m; optional inspection distance 2 to 65cm, which is slightly further than the normal near-field inspection distance of 40cm; and optional inspection distance 3 to 30cm, which is closer than 40cm.

[0128] Note that 42d in Figure 16B is a changeability mark; optional inspection distances with a check mark can be changed by the user. Conversely, those without a check mark (e.g., marked with an "X") cannot be changed by the user. This is because the control unit 26 is restricting changes to prevent them from being altered because an inspection at that optional inspection distance is currently being performed. If an inspection at an optional inspection distance is not being performed, the control unit 26 will place a check mark on the changeability mark 42d to indicate that all optional inspection distances can be changed.

[0129] (4) Once the optional inspection distance has been changed, the inspector presses the "OK" button 42e. Upon receiving this input, the control unit 26 stores the changed optional inspection distance in the storage unit 29 and closes the window 42. This completes the change of the optional inspection distance.

[0130] (5) On the other hand, if the examiner does not want to change the optional inspection distance, the examiner presses the "Cancel" button 42f. Upon receiving this input, the control unit 26 closes the window 42 without storing the optional inspection distance in the storage unit 29.

[0131] As mentioned above, the optional inspection distance can be changed while the subjective inspection is being conducted. Therefore, if the optional inspection distance is changed while the subjective inspection is in progress and the measurement results at the optional inspection distance have been recorded, the control unit 26 will discard the measurement results at that inspection distance instead of storing them in the storage unit 29.

[0132] [Switch to optional inspection distance] Switching to an optional test distance can be done when the measurement mode is in "prescription mode". In other words, to switch to an optional test distance set in Figure 15 or Figure 16B and perform the test at that optional test distance, the measurement mode must be set to "prescription mode". This "prescription mode" is a mode for correcting each correction value measured in the subjective test and creating and recording an actual prescription, and the acquired "prescription data" is recorded as a prescription. The examiner can switch to an optional test distance and perform the measurement by following the procedure below.

[0133] (1) The examiner presses the "Prescription: Set" [Final: Set] button (or "Prescription: Record" [Final Mem] button) 41d in the function buttons at the bottom of the subjective examination screen 41. If there is a record of any prescription, this button 41d will display "Prescription: Set", and if there is no record of a prescription, it will display "Prescription: Record". Upon receiving this operation, the control unit 26 switches the main data in the main data area 41e to prescription data (recorded prescription).

[0134] (2) The examiner presses the "Test distance display / change area" button 41f (see Figure 16A) located at the top of the self-examination screen 41. In response to this operation, the control unit 26 displays a list of selectable test distances, i.e., the "Test distance list" 41g, on the self-examination screen 41, as shown in Figure 17.

[0135] (3) The examiner selects an optional test distance from the displayed "test distance list" 41g. In response to this selection, the control unit 26 executes the processes of steps S8 to S10 shown in Figure 9 based on the selected optional test distance, similar to the first embodiment described above. Specifically, in order to orient the visual axis of the eye under examination E according to the test distance, the control unit 26 drives the left and right X-direction rotation drive units 24 according to the test distance to rotate the left and right measuring heads 16 in the X direction (step S8), and moves the first focusing lens 32e to a position according to the test distance (step S9). Next, the control unit 26 controls the target projection system 32 to display an indicator on the display 32a with presentation conditions such as magnification according to the test distance, and displays the same target on the display surface 30a of the display unit 30 (steps S10, S11). (4) This allows the subject to undergo testing at the selected optional testing distance. Upon receiving a response from the subject, etc., the control unit 26 analyzes the response and obtains measurement results such as visual acuity values ​​(step S12).

[0136] Then, once the subjective examination is completed for all optional test distances selected by the examiner, the control unit 26 displays a list and graph of the measurement results on the display surface 30a, and prints the measurement results if the examiner requests printing (step S14).

[0137] Figures 18A and 18B show output samples of measurement results. Figure 18A is an output sample printed on roll-shaped thermal paper, and Figure 18B is an output sample printed on A4 paper. These output samples have the spherical power and visual acuity values ​​measured at the normal distance test distance, near test distance, and the first to third optional test distances printed for each test distance. The measurement results at the normal distance test distance (first test distance), near test distance (second test distance), and the first to third optional test distances (third test distance) are printed in order of the length of the test distances, as test distance 1 to test distance 5. In the example of Figures 18A and 18B, the "spherical power" measured at each test distance is output, but this is not limited to this. For example, instead of, or in addition to, the add power or difference relative to the spherical power at the first test distance may be printed.

[0138] This embodiment describes the measurement method, which allows measurement at an optional examination distance. Measurement at an optional examination distance can be performed after the refractive correction for the basic distance examination distance (far point) or near examination distance (near point) has been determined, for the purpose of confirming whether sufficient visual acuity is obtained when fixating on other distances and what spherical curvature is required to obtain sufficient visual acuity.

[0139] Therefore, during examinations at optional examination distances, it is possible to adjust spherical power and record visual acuity values. Furthermore, even during examinations at optional examination distances, the control unit 26 allows the examiner to input data in the main data area 41e so that the examiner can change the cylinder power and cylinder axis. However, since these values ​​are treated as common values ​​for other examination distances as well, the control unit 26 restricts the examiner's input data so that the values ​​of cylinder power and cylinder axis changed at optional examination distances are not changed in the main data area 41e even when the examination distance is switched.

[0140] Furthermore, subjective examinations include phoria tests and binocular function tests to examine how the eyes see with both eyes. In this embodiment, these tests can be performed at all test distances, that is, not only at the normal distance test distance (first test distance) and near test distance (second test distance), but also at an optional test distance (third optional test distance). The control unit 26 displays the prism values ​​obtained from these tests for each test distance and stores them in the memory unit 29. Note that phoria tests and binocular function tests do not necessarily have to be performed at optional test distances. If these tests are not performed at an optional test distance, the control unit 26 displays the prism values ​​measured at the distance test distance or near test distance as the prism values ​​for the optional test distance and stores them in the memory unit 29.

[0141] The reasons for this specification are that even if strabismus and binocular vision function tests are performed at various testing distances, when creating prescriptions for bifocal glasses or multifocal IOLs, only one prism amount can be prescribed for these lenses. Furthermore, the convergence state of the eye E changes depending on the testing distance, making the correspondence between the convergence state and the testing distance complex. For these reasons, there is little need to perform strabismus and binocular vision function tests at optional testing distances, and by not performing them, it is possible to improve testing efficiency and simplify and clarify the testing distances.

[0142] Furthermore, for similar reasons, during examinations at optional examination distances, the control unit 26 may restrict user input so that strabismus examinations and binocular vision function examinations cannot be performed. In this case, the control unit 26 also restricts user input so that the examiner cannot select charts (visual targets) registered for strabismus examinations and binocular vision function examinations within the chart page 41h (see Figure 17, etc.).

[0143] As mentioned above, the examiner or other user can set the optional examination distance within the range of 6.0m to 25cm (20 feet to 10 inches). The control unit 26 also treats examination distances of 1.0m or more (above the threshold) as distance examination distances (far vision) and examination distances of less than 1.0m (below the threshold) as near examination distances (near vision), and sets the conditions for presenting the visual acuity targets. When switching examination distances, if switching from one distance distance to another distance distance, or from one near distance to another near vision distance, the currently running examination conditions and charts (visual targets) are carried over. However, if the distance and near thresholds (e.g., 1.0m) are crossed, the charts (visual targets) are not carried over, but the control unit 26 controls each part of the ophthalmic device 10 so that the visual acuity test is automatically performed with a chart appropriate to the examination distance.

[0144] Next, we will explain the refraction power displayed in the main data area 41e during testing at the optional testing distance. When the optional testing distance is the distance testing distance, the value displayed in the "ADD" field of the main data area 41e is the value obtained by subtracting the current spherical power set on the measuring head from the near spherical power ("Exam Distance (Near Point)" = Spherical power of "Exam Distance (Far Point)" + ADD of "Exam Distance (Near Point)").

[0145] In other words, the control unit 26 displays the add degree ADD2 calculated by the following equation (2) in the "Add" ("ADD") of the main data area 41e. In equation (2) below, ADD2 is the add degree at the optional inspection distance (third inspection distance), S1 is the sphericity at the far inspection distance (far inspection distance, first inspection distance), ADD1 is the add degree at the near inspection distance (near inspection distance, second inspection distance), and S2 is the sphericity at the said optional inspection distance (third inspection distance) (the sphericity currently set for the measuring head 16).

[0146] ADD2 = S1 + ADD1 - S2 (2)

[0147] On the other hand, when the optional inspection distance is set to the near inspection distance, the control unit 26 displays the distance sphericity measured at the first inspection distance, i.e., the distance sphericity measured at the first inspection distance, in the "Spherical" ("S") field of the main data area 41e, and displays the value obtained by subtracting the sphericity displayed in "Spherical" ("S") from the sphericity currently set for the measuring head 16, in the "Add" ("ADD") field.

[0148] Furthermore, in subjective examinations, one method of astigmatism testing is the cross-cylinder test, in which refractive power is applied to an astigmatism test target in a predetermined direction and presented to the eye E being examined. During this cross-cylinder test, it is sometimes desirable to maintain equivalent sphericality by adjusting the sphericality at all test distances.

[0149] In this embodiment, the user can set whether or not to maintain equivalent sphericity on the setting screen 40. When the setting to maintain equivalent sphericity is ON, each time the user changes the cylinder power during the cross cylinder inspection, the control unit 26 changes or adjusts the sphericity to maintain equivalent sphericity and displays it on the display surface 30a. This change or adjustment of sphericity is also applied to the inspection distance of the optional inspection distance. Here, maintaining equivalent sphericity means that during testing at a predetermined inspection distance, the value of S + C / 2 is kept constant by adjusting the sphericity S and / or astigmatism power C.

[0150] Although the ophthalmic apparatus of this disclosure has been described above based on embodiments and modified examples, the specific configuration is not limited to these embodiments and modified examples, and changes or additions to the design are permitted as long as they do not deviate from the gist of the invention as described in each claim of the patent.

[0151] The ophthalmic apparatus 10 shown in the first and second embodiments described above has a measurement optical system 21 comprising an observation system 31, a target projection system 32, a subjective examination system 34, a first alignment system 35, a second alignment system 36, and an objective measurement optical system consisting of an ocular refractive power measurement system 33 and a keratological system 37. However, the ophthalmic apparatus is not limited to this configuration. Another example of a different ophthalmic apparatus is the one described in U.S. Patent No. 7,775,662 (which is incorporated in whole by reference). This ophthalmic apparatus comprises an ophthalmic optical system (phoropter) and a target presentation device, which are positioned between the eye under examination E and the target projection system and have multiple optical members for correcting the visual function of the eye under examination, with each optical member selectively positioned between the eye under examination and the target projection system. In such ophthalmic devices, as disclosed in this application, the target presentation device presents targets by changing presentation conditions such as the examination distance, thereby enabling adjustment of the sphericality and recording of visual acuity values ​​at three optional examination distances, in addition to the basic distance vision and near vision examination distances. Therefore, the examination distance and target presentation conditions can be changed as desired, making it possible to quickly and easily measure the ocular characteristics of the eye under examination at various examination distances and presentation conditions, thereby improving measurement efficiency. [Explanation of Symbols]

[0152] 10 Ophthalmic device 21 Measurement optical system 26 Control unit 30 Display unit 32. Visual target projection system 33. Refractive power measurement system (objective measurement optical system) 37 Keratological system (objective measurement optical system) 30b Input unit E Eye under examination

Claims

1. A target projection system that presents a target to the eye under examination at a predetermined examination distance and with presentation conditions corresponding to that examination distance, A control unit for controlling the aforementioned target projection system, It comprises an input unit that accepts input operations from the user, The control unit controls the target projection system to present the target at a first examination distance for distance vision testing of the eye under examination, a second examination distance for near vision testing, and at least one third examination distance different from the first and second examination distances. Based on the input operation from the input unit, measurement results are acquired, and the measurement results acquired at a distance greater than or equal to the threshold are recorded as the measurement results for long-distance testing, and the measurement results acquired at a distance less than the threshold are recorded as the measurement results for close-up testing. An ophthalmic device characterized by the following features.

2. The control unit controls the target projection system to present the target at a plurality of preset different inspection distances, which are the third inspection distances. The ophthalmic device according to feature 1.

3. The control unit controls the target projection system so that, at the third examination distance, it can display the target for measuring the sphericalness of the eye under examination, the target for measuring the degree of astigmatism, and the target for measuring the axis of astigmatism. The ophthalmic device according to feature 1.

4. The system includes an input unit that receives input of correction values ​​for correcting visual function, including the sphericity, astigmatism power, and astigmatism axis of the eye being examined, and a display unit that displays the input correction values. The control unit displays the correction value input from the input unit on the display unit and controls the target projection system to present the target according to the presentation conditions corresponding to the correction value. The ophthalmic device according to feature 1.

5. When the control unit is presenting the target at the third examination distance, and the third examination distance is the examination distance for near vision testing, the control unit displays the addition degree to the spherical correction value input at the first examination distance as the spherical correction value on the display unit. The ophthalmic device according to feature 4.

6. When the control unit is presenting the target at the third inspection distance, and the third inspection distance is the inspection distance for distance vision testing, the following equation is used: ADD2= S1 + ADD1 - S2 (In the above formula, ADD2 is the add-in degree at the third inspection distance, S1 is the sphericity degree at the first inspection distance, ADD1 is the add-in degree at the second inspection distance, and S2 is the sphericity degree at the said third inspection distance.) The addition degree ADD2 calculated by this method is displayed on the display unit. The ophthalmic device according to feature 4.

7. When the control unit receives input of the corrected value of the astigmatism power from the input unit, if the inspection distance is the inspection distance for distance vision testing, it changes the sphericity to maintain the equivalent sphericity and displays it on the display unit. The ophthalmic device according to feature 4.

8. The system includes an objective measurement optical system for measuring the ocular characteristics of the eye being examined, The control unit controls the target projection system to present the target at each test distance based on the measurement results from the objective measurement optical system. The ophthalmic device according to feature 1.

9. The optometry optical system comprises a plurality of optical members positioned between the eye under examination and the target projection system for correcting the visual function of the eye under examination, and selectively positioning each optical member between the eye under examination and the target projection system. The ophthalmic device according to feature 1.

10. A method for measuring ocular characteristics performed with the ophthalmic apparatus described in claim 1, The control unit controls the target projection system to present the target to the eye under examination at the first examination distance, The control unit controls the target projection system to present the target to the eye under examination at the second examination distance, The control unit controls the target projection system to present the target to the eye under examination at at least one of the third examination distances, The control unit acquires measurement results based on the input operation from the input unit, and records the measurement results acquired at a distance greater than or equal to a threshold as the measurement results for long-distance inspection, and the measurement results acquired at a distance less than the threshold as the measurement results for close-up inspection. A measurement method characterized by including the following.

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