Ophthalmologic apparatus and ophthalmologic apparatus control program
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- NIDEK CO LTD
- Filing Date
- 2023-06-29
- Publication Date
- 2026-05-27
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present disclosure relates to an ophthalmic apparatus that examines a subject's eye, and an ophthalmic apparatus control program. [Background technology]
[0002] There are various types of ophthalmic devices for examining a subject's eye, including an ocular refractive power measuring device, an intraocular pressure measuring device, an optical coherence tomography (OCT), a scanning laser ophthalmoscope (SLO), a fundus camera, a visual field measuring device, a corneal shape measuring device, a corneal endothelium imaging device, etc. These ophthalmic devices perform examinations with the ophthalmic examination unit aligned at an appropriate position relative to the subject's eye.
[0003] When aligning the optometry section with the subject's eye, if an image of the subject is captured and displayed on the display unit, unnecessary information such as the background or the subject's clothing may be displayed on the display unit. This can be annoying to the examiner or observer, or information unnecessary for the examination may be displayed on the display screen.
[0004] To address this problem, an ophthalmic device has been proposed that limits the display of captured images on a display screen (see, for example, Patent Document 1). [Prior art documents] [Patent documents]
[0005] [Patent Document 1] Patent Publication No. 2022-80459 Summary of the Invention [Problem to be solved by the invention]
[0006] In the embodiment of the above-mentioned Patent Document 1, a technique is disclosed in which a message window is superimposed on a captured image until a subject is detected. However, in this case, when an examiner aligns the optometry unit with the subject's eye, the subject's face is hidden by the message window, which makes it difficult to guide or move the optometry unit to the subject's face while looking at the display screen.
[0007] In view of the above-described conventional techniques, the present disclosure has as its technical object to provide an ophthalmic apparatus capable of reducing the inconvenience of information unnecessary for the examination being reflected on the display screen. [Means for solving the problem]
[0008] (1) An ophthalmic device according to a first aspect of the present disclosure is an ophthalmic device having an ophthalmology section for examining a subject's eye, and is equipped with an illumination means for irradiating the subject with illumination light, an imaging means for acquiring a captured image by photographing the subject, a display means for displaying the captured image, and a control means, wherein the control means increases at least one of the illumination light amount of the illumination means and the gain of the imaging means to cause the captured image displayed on the display means to be blown out. (2) An ophthalmic device control program according to a second aspect of the present disclosure is an ophthalmic device control program executed in an ophthalmic device having an ophthalmology examination unit for examining a subject's eye, and is characterized in that, when executed by a control unit, it causes the ophthalmic device to execute an illumination step of irradiating illumination light onto the subject, an imaging step of acquiring a captured image by imaging the subject with an imaging means, a display step of displaying the captured image, and a control step of blowing out the whiteout of the captured image displayed in the display step by increasing at least one of the illumination light amount in the illumination step and the gain of the imaging means in the imaging step. [Brief description of the drawings]
[0009] [Figure 1] 1A and 1B are diagrams illustrating an external configuration and an optical system configuration of an ophthalmic apparatus. [Diagram 2] FIG. 2 is a diagram showing an ophthalmologic apparatus as seen from the subject's side. [Diagram 3] 4 is a diagram for explaining the arrangement of a measurement light source provided in a projection optical system; FIG. [Figure 4] FIG. 2 is a diagram showing a schematic configuration of a control system in an ophthalmic apparatus. [Diagram 5] 2 is a diagram illustrating a capture area of an image captured by an image sensor; FIG. [Figure 6] 13 is an example of an image captured when the illumination light amount and the gain of the image sensor are set according to the conditions during inspection (measurement). [Figure 7] 4 is a flowchart showing a control operation of the ophthalmic apparatus of the present embodiment. [Figure 8] 7 is an example of a captured image when the illumination light amount and the gain of the image sensor are increased with respect to the display of the captured image in FIG. 6. [Figure 9] FIG. 13 is a diagram showing an example of a display screen when alignment of the optometry unit with respect to the subject's eye is completed. [Figure 10] FIG. 2 is a diagram for explaining measurement of eye refractive power by a photorefraction method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] [overview] Hereinafter, one exemplary embodiment will be described with reference to the drawings. Note that the items grouped in <> below can be used independently or in conjunction with each other.
[0011] For example, an ophthalmic device (e.g., the ophthalmic device 1) includes an ophthalmic examination unit (e.g., the ophthalmic examination unit 2). For example, the ophthalmic device includes an illumination unit (e.g., an illumination optical system 30), an imaging unit (e.g., an image sensor 24), a display unit (e.g., a display 5), and a control unit (e.g., a control unit 50).
[0012] <Ophthalmology Department> For example, the optometry unit is used to examine the subject's eye. For example, the optometry unit includes an examination optical system (for example, a measurement optical system 10). For example, the examination optical system may be a measurement optical system that measures the eye characteristics of the subject's eye, an OCT optical system that obtains a tomographic image of the eye tissue, or an imaging optical system that images the tissue of the anterior part of the eye or the fundus of the subject's eye. For example, the examination optical system may be a measurement optical system that objectively measures the eye refractive power of the subject's eye by a photorefraction method. In this case, the measurement optical system includes a light projecting optical system (for example, a light projecting optical system 10a) that projects measurement light onto the subject's eye, and a light receiving optical system (for example, a light receiving optical system 10b) that receives return light (reflected light) of the measurement light from the subject's eye, and the light receiving optical system may have an image sensor that receives the return light from the subject's eye.
[0013] For example, the optometry section is provided with an illumination means (e.g., an illumination optical system 30) and an imaging means (e.g., an image sensor 24). For example, the optometry section is moved to align the examination optical system with the subject's eye. For example, the optometry section may be provided with an observation optical system (e.g., an observation optical system 40). The observation optical system is used to observe the subject and the subject's eye.
[0014] <Lighting means> For example, the illumination means is used to irradiate the subject with illumination light. For example, the illumination means includes an illumination light source (e.g., illumination light source 32). For example, the illumination light source emits near-infrared light. For example, a plurality of illumination light sources may be provided. For example, when the inspection optical system is a photorefraction type measurement optical system, the illumination means may also be used as the light projection optical system of the measurement optical system.
[0015] <Method of filming> For example, the photographing means captures a photographed image by photographing the subject illuminated by the illumination means. For example, the photographing means may be provided in an observation optical system (e.g., the observation optical system 40) provided in the optometry section. For example, the photographing means is configured to be able to change the gain of the photographed image to be acquired. For example, when the examination optical system is a photorefraction type measurement optical system, the photographing means may also serve as an image sensor provided in the light receiving optical system of the measurement optical system. That is, the photographed image may be acquired by photographing the subject using the photographing means (image sensor) provided in the measurement optical system.
[0016] <Control Means> For example, the control means controls the increase and decrease (increase and decrease) of the illumination light amount of the illumination means. For example, the control means controls the increase and decrease of the gain of the imaging means. For example, the control means increases at least one of the illumination light amount of the illumination means and the gain of the imaging means, thereby causing the captured image displayed on the display means to be blown out. In other words, the control means increases at least one of the illumination light amount of the illumination means and the gain of the imaging means so that the captured image displayed on the display means is blown out. This reduces the inconvenience of information unnecessary for the inspection being reflected on the display screen. Note that, for example, blown out highlights of a captured image are when the gradation (brightness) of the captured image is saturated. As a result, a white part with high brightness appears in the captured image. This blown out highlights erases information unnecessary for the inspection that was included in the captured image, and it does not appear on the display screen.
[0017] For example, the control means may increase both the amount of illumination light from the illumination means and the gain of the imaging means so that whiteout areas appear in the captured image. When the control means increases the amount of illumination light from the illumination means, the control means may increase the amount of light from the illumination light source itself, may increase the number of illumination light sources that are turned on, or may increase the amount of illumination light by using a light-attenuating filter and removing the light-attenuating filter arranged in the illumination light path.
[0018] For example, the control means may blow out the captured image to a level where the subject's face (e.g., left and right eyes) can be identified in the captured image when the optometry unit is located at a predetermined examination distance (working distance) from the subject. In other words, the upper limit of the degree of blown out highlights may be set to a level where the subject's eye can be detected in the captured image when the optometry unit is located at a predetermined examination distance from the subject. This allows the examiner to move the optometry unit to the subject's eye while observing the captured image, even if the subject's clothes, etc. are blown out, as long as the examiner can at least identify the subject's eye. In addition, in a configuration where the optometry unit is automatically moved, the optometry unit can be moved based on the detection of the subject's eye.
[0019] For example, the degree of whiteout on the captured image may be set to a level at which a corneal reflection bright spot formed on the test eye by the illumination light of the illumination optical system and the pupil around the bright spot can be detected on the captured image. In this case, the degree of whiteout may be set to a level at which the pupil is not bright inside the captured image and the pupil can be detected as a black part. This allows the test eye to be properly detected and the eye examination unit to be properly aligned with the test eye.
[0020] Also, for example, the lower limit of the degree of overexposure may be adjusted to a level where the white parts of the subject's clothes are overexposed when the subject is positioned at a predetermined examination distance from the optometry unit. In this case, the degree of overexposure may be adjusted so that the cheeks and forehead of the subject's face are overexposed. The degree of overexposure can be determined by experiment.
[0021] For example, the control means may increase at least one of the illumination light amount and the gain of the imaging means applied during the examination of the subject's eye in order to cause the photographed image obtained during the alignment of the optometry unit with the subject's eye to have whiteout. Also, for example, the control means may return (reduce) the illumination light amount and the gain of the imaging means that have been increased to cause whiteout in the photographed image during the examination of the subject's eye to a predetermined examination level applied during the examination. This allows the adjustment of whiteout to be completed and the conditions at the time of the examination to be restored, thereby allowing the examination to be performed appropriately. Note that, for example, the predetermined examination levels related to the illumination light amount and the gain of the imaging means may be set to a level that does not cause whiteout or halation in the photographed image so that the examination (measurement) of the subject's eye can be analyzed based on the photographed image.
[0022] For example, the control means may perform a process of returning (reducing) the illumination light amount and the gain of the imaging means, which have been increased to cause whiteout in the captured image, to a predetermined examination level based on any one of a detection signal of the eye to be examined, a completion signal indicating the completion of alignment of the optometry unit with respect to the eye to be examined, an examination start signal for starting examination by the optometry unit, and an operation signal operated by the examiner to end whiteout in the captured image. In this case, the ophthalmic apparatus includes a signal receiving means (e.g., the control unit 50) that receives at least one of the detection signal of the eye to be examined, the completion signal indicating the completion of alignment, the examination start signal, and the operation signal operated by the examiner.
[0023] For example, when a detection signal of the test eye is used to eliminate blown-out highlights in a captured image, the ophthalmologic device is provided with an index projection means (e.g., illumination optical system 30) that projects and forms an index on the test eye, and an index detection means (e.g., observation optical system 40), and a detection signal of the test eye is output when the index formed on the test eye is detected by the index detection means.
[0024] For example, when an alignment completion signal is used to end blown-out highlights in a captured image, the ophthalmic device is provided with a judgment means (e.g., the control unit 50) that judges whether the index detected by the index detection means is within a predetermined allowable range, and the alignment completion signal is output by the judgment means.
[0025] For example, when an examination start signal is used to end blown-out highlights in a captured image, the examination start signal may be output automatically based on a determination that alignment is complete by a determination means provided in the ophthalmic device, or the ophthalmic device may be provided with an operation switch that inputs a trigger signal to start the examination, and the examination start signal may be output when the examiner operates the operation switch.
[0026] For example, when an operation signal operated by the examiner is used to end whiteout in a captured image, the ophthalmic device may be provided with an operation means (e.g., operation unit 52) operated by the examiner, and the operation signal may be output by operating the operation means by the examiner.
[0027] <Control program> In addition, the present disclosure is not limited to the devices described in the present embodiment. For example, a control program (software) that performs the functions of the following embodiments is supplied to a system or device via a network or various storage media. Then, a control device (e.g., a CPU, etc.) of the system or device can read and execute the program.
[0028] For example, an ophthalmic device control program executed in an ophthalmic device is executed by a control unit to cause the ophthalmic device to execute an illumination step of irradiating an examinee with illumination light, an imaging step of acquiring an image by imaging the examinee with an imaging means, a display step of displaying the image, and a control step of blowing out highlights in the image displayed in the display step by increasing at least one of the illumination light amount in the illumination step and the gain of the imaging means in the imaging step. This reduces the inconvenience of information unnecessary for the examination being reflected on the display screen.
[0029] [Example] An example of the present embodiment will be described with reference to the drawings. Fig. 1 is a diagram for explaining the external configuration and the configuration of the optical system of an ophthalmic apparatus 1 according to the example, and is a diagram of the ophthalmic apparatus 1 as viewed from the side. Fig. 2 is a diagram of the ophthalmic apparatus 1 as viewed from the subject side.
[0030] In this embodiment, an ophthalmic device 1 that objectively measures the ocular refractive power of a subject's eye using a photorefraction method will be described as an example. In the photorefraction method of ocular refractive power measurement, for example, the ocular refractive power of the subject's eye is objectively obtained from the ratio of the light reflected from the fundus of the subject's eye to the pupil. In this embodiment, a handheld ophthalmic device 1 will be described as an example.
[0031] 1 and 2, an ophthalmic apparatus 1 includes an eye examination unit 2. Inside the eye examination unit 2, an optical system including a measurement optical system 10 for objectively measuring the ocular refractive power of the subject's eye by a photorefraction method is disposed. A measurement window 3 located on an optical axis L1 of the measurement optical system 10 is provided on the side of the eye examination unit 2 facing the subject's eye. In addition, a distance detector 9 for detecting the distance from the subject may be disposed on the subject side of the eye examination unit 2. For example, an ultrasonic sensor is used as the distance detector 9.
[0032] In addition, a display 5 is disposed on the opposite side of the measurement window 3 in the optometry unit 2. A gripping part 7 to be held by the examiner is attached to the bottom of the optometry unit 2. The examiner can move the optometry unit 2 relative to the subject's eye by holding the gripping part 7 with one hand. In Fig. 1, the left-right direction relative to the subject's eye (examinee) is defined as the X direction, the up-down direction is defined as the Y direction, and the front-back direction (working distance direction) is defined as the Z direction.
[0033] The measurement optical system 10, the illumination optical system 30, and the observation optical system 40, which are examples of examination optical systems arranged in the optometry section 2, will be described below.
[0034] <Measurement optical system> The measurement optical system 10 includes a light projecting optical system 10a and a light receiving optical system 10b. The light projecting optical system 10a includes a measurement light source 13. For example, a red LED (light emitting diode) that emits near-infrared light is used as the measurement light source 13. The light receiving optical system 10b includes an objective lens 22 and an image sensor 24.
[0035] 3 is a diagram for explaining the arrangement of the measurement light source 13 provided in the light projection optical system 10a, and shows a diagram when viewed from the subject's eye side. For example, as the measurement light source 13, a plurality of measurement light sources are provided and arranged separately from each other in at least three meridian directions. In this embodiment, as the measurement light source 13, eight sets of measurement light sources (measurement light source 13a, measurement light source 13b, measurement light source 13c, measurement light source 13d, measurement light source 13e, measurement light source 13f, measurement light source 13g, measurement light source 13h) are arranged in four meridian directions.
[0036] For example, eight sets of measurement light sources, ie, measurement light sources 13a to 13h, are arranged at 45° intervals on a concentric circle outside the outer circumferential circle of the objective lens 22. These measurement light sources 13 are fixed to the base 14. The objective lens 22 may be fixed to the base 14. Each of the eight sets of measurement light sources 13a to 13h has three measurement light sources. For example, in the measurement light source 13a, three light sources 13a1, 13a2, and 13a3 are arranged at predetermined intervals in the meridian direction (radial direction) with the optical axis L1 as a reference, in order from the optical axis L1. For the other seven sets of measurement light sources 13b to 13h, the reference symbols in FIG. 3 are omitted, but three light sources are similarly arranged at predetermined intervals in order from the optical axis L1. That is, the eight measurement light sources are arranged on three different concentric circles outside the outer circumferential circle of the objective lens 22.
[0037] By turning on these measurement light sources 13, the measurement light is projected onto the subject's eye, illuminating the anterior segment of the subject's eye and causing the measurement light to enter the pupil. Each measurement light source is independently controlled by a control unit 50, which will be described later. For example, the turning on of each measurement light source, the adjustment of the light amount, etc. are independently controlled.
[0038] The return light (reflected light) from the test eye of the measurement light by the light projection optical system 10a is received by the image sensor 24 via the objective lens 22 of the light receiving optical system 10b, and an image of the anterior part of the test eye including the pupil is captured by the image sensor 24 to obtain a photographed image.
[0039] <Illumination optical system> The illumination optical system 30 is used to illuminate the subject. The illumination optical system 30 includes an illumination light source 32 that emits near-infrared light. Of course, different types of light sources may be used. The illumination light from the illumination light source 32 is irradiated onto the subject, thereby illuminating the face of the subject, including the eyes. There may be a plurality of illumination light sources 32. In this embodiment, as shown in FIG. 2, four illumination light sources 32 are arranged symmetrically on the outside of the measurement window 3 with the optical axis L1 as the center. The illumination optical system 30 may also be used as the measurement light source 13.
[0040] In this embodiment, the illumination optical system 30 also serves as an alignment target projection optical system that forms a bright spot, which is an example of an index for alignment detection, on the cornea of the subject eye. Of course, an alignment target projection optical system may be provided separately from the illumination optical system 30.
[0041] <Observation optical system> The observation optical system 40 is used to obtain a photographed image of the subject illuminated by the illumination optical system 30. In this embodiment, the observation optical system 40 serves both as the objective lens 22 and the image sensor 24 of the measurement optical system 10 (light receiving optical system 10b). The observation optical system 40 may be provided separately from the light receiving optical system 10b of the measurement optical system 10, and may have an image sensor separate from the image sensor 24. The subject (face including the subject's eye) illuminated by the illumination optical system 30 is photographed by the image sensor 24 via the objective lens 22. The photographed image photographed by the image sensor 24 is displayed on the screen of the display 5, which is an example of a display means. The photographed image displayed on the display 5 is used as an observation image for aligning the optometry unit 2 with respect to the subject's eye.
[0042] In this embodiment, the observation optical system 40 also serves as an alignment index detection optical system that detects an index (corneal reflection bright spot) formed on the subject's eye by the alignment index projection optical system. Of course, an alignment index detection optical system may be provided separately from the observation optical system 40.
[0043] <Control system configuration> FIG. 4 is a diagram showing a schematic configuration of a control system in the ophthalmic apparatus 1. The control unit 50 controls each part of the ophthalmic apparatus 1. The control unit 50 includes a CPU (processor), RAM, ROM, etc. The display 5, the measurement light source 13, the image sensor 24, and the illumination light source 32 are connected to the control unit 50. The control unit 50 processes the image captured by the image sensor 24. In other words, in this embodiment, the control unit 50 also functions as an image processing unit. The control unit 50 also serves as a receiving means for receiving various signals.
[0044] The control unit 50 is also connected to an operation unit 52 and a memory 54, which is an example of a storage means. The operation unit 52 inputs various operation signals by the examiner's operation. The operation unit 52 may be at least one of a mouse, a joystick, a keyboard, a touch panel, and the like. For example, the display 5 may have the function of the operation unit 52 by being a touch panel. For example, the operation unit 52 may include a trigger switch that inputs a measurement start signal. The control unit 50 also functions as a reception unit that receives an operation signal from the operation unit 52. The memory 54 stores measurement results, photographed images of the subject's eye, and the like. In addition, various programs for controlling the operation of the ophthalmic apparatus 1 are stored.
[0045] <Operation> The operation of the device having the above configuration will be described. The examination in the ophthalmologic device 1 of this embodiment is an example of a photorefraction method that objectively measures the ocular refractive power of the subject's eye, and the working distance (examination distance) for the subject's eye is set to 1 m, and the image sensor 24 is examined (measured) in an aligned state that includes both of the subject's eyes.
[0046] Here, when aligning the optometry unit 2 with respect to the subject's eye, since the ophthalmic device 1 of this embodiment is a handheld device, the optometry unit 2 may not be immediately moved to face the subject's eye. In this case, for example, as shown in FIG. 5, the photographing area 110 of the photographed image captured by the image sensor 24 may not be present on the subject's face, and in the process of aligning the optometry unit 2 with the subject's eye, the photographed image of the subject's clothes, etc. may be displayed on the screen of the display 5 as shown in FIG. 6. If information unnecessary for the examination, such as the subject's clothes, is displayed on the display 5 as shown in FIG. 6, attention may be drawn to unnecessary parts, and in some cases, the subject's personal information may be misused.
[0047] In order to improve the inconvenience of such information unnecessary for the examination being reflected on the display screen, in this embodiment, the control unit 50 increases (adjusts) at least one of the illumination light amount of the illumination optical system 30 and the gain of the image sensor 24 so that the captured image displayed on the display 5 becomes "overexposed." In other words, "overexposed" means that the gradation (brightness) of the captured image is saturated, which results in the appearance of bright white areas in the captured image. The illumination light amount and the degree of increase in the gain of the image sensor 24 when the captured image becomes "overexposed" may be determined by experiment.
[0048] For example, when the optometry unit 2 is located at a predetermined working distance (1 m in this embodiment) from the subject's eye, the illumination light amount is increased to a level at which the pupil is detected on the captured image. For example, the illumination light amount is increased to a level at which the illumination light from the illumination optical system 30 enters the pupil of the subject's eye, and the pupil is not brightened (no luminance gradient occurs in the pupil) on the captured image captured by the image sensor 24 due to the reflected light from the fundus of the subject's eye, and the pupil is detectable as a black part. Also, the illumination light amount is increased to a level at which the outlines of the pupil and the iris are detected as distinguishable on the captured image. For example, the gain of the image sensor 24 is increased so that the white clothing parts worn by the subject and the cheeks and forehead parts of the subject's face are "blown out".
[0049] 6 shows an example in which the illumination light amount of the illumination optical system 30 and the gain of the image sensor 24 are set under the conditions (examination level) during the examination (measurement) by the measurement optical system 10. In this case, the illumination light amount and the gain of the image sensor 24 are set to a level that does not cause whiteout or halation in the captured image so that the examination (measurement) of the subject's eye can be analyzed based on the captured image. For example, in this embodiment, two of the four illumination light sources 32 are turned off during the examination. Also, the gain of the image sensor 24 is adjusted to a level that does not cause "whiteout" in the captured image of the object located at a predetermined distance (a working distance of 1 m in this embodiment).
[0050] The control operation of the ophthalmic apparatus 1 will be described below with reference to the flowchart of Fig. 7. Fig. 7 is a flowchart showing the control operation of the ophthalmic apparatus of this embodiment.
[0051] When the power switch of the ophthalmologic apparatus 1 is turned on, first, a screen for inputting subject information such as the ID and age of the subject is displayed on the display 5 (S1). The examiner operates the operation unit 52 to input the subject information. Next, when a start button of the operation unit 52 is pressed, the signal is received by the control unit 50 (S2). When the start button signal is received, the display screen of the display 5 is switched to displaying a captured image captured by the image sensor 24, and at least one of the illumination light amount of the illumination optical system 30 and the gain of the image sensor 24 is increased relative to the illumination light amount and the gain of the image sensor 24 applied during normal examination (measurement) under the control of the control unit 50 (S3). In this embodiment, the four illumination light sources 32 are turned on, so that the illumination light amount is increased and the gain of the image sensor 24 is increased to a preset level.
[0052] The examiner holds the ophthalmologic apparatus 1 in his / her hands and moves the optometry section 2 so that the face of the examinee (the eye to be examined) is displayed on the display 5. Note that the examinee is positioned, for example, sitting on a chair.
[0053] Here, even if the photographing area 110 shown in FIG. 5 is located on the subject's clothing during the process of aligning the optometry unit 2 with the subject's eye, the display screen of the display 5 displays a photographed image in which the clothing part is overexposed as shown in FIG. 8, in contrast to the photographed image shown in FIG. 6. This reduces the inconvenience of information unnecessary for the examination being reflected on the display screen. It is also possible to prevent the examiner from misusing the subject's personal information. In the example of FIG. 8, the dotted line area 220 is the overexposed part.
[0054] In addition, highlight blowout is unlikely to occur in the subject's body and facial contours, and characteristic parts in the face, such as the eyes, nose, and mouth, which have a small amount of reflected light from the illumination optical system 30. Therefore, while looking at the display screen of the display 5, the examiner can move the optometry unit 2 so that the subject's face and the examined eye appear on the display screen.
[0055] 9 is a diagram showing an example of a display screen when the alignment of the optometry unit 2 with respect to the subject's eye is completed. In the photorefraction type eye refractive power measurement of this embodiment, the eye refractive power is obtained based on a captured image including both the left and right eyes of the subject. For this reason, the alignment of the optometry unit 2 with respect to the subject's eye in the XY directions is performed by aligning the centers of both the left and right eyes of the subject's eye with respect to the optical axis L1. In this embodiment, the alignment of the optometry unit 2 with respect to the subject's eye in the Z direction (working distance direction) is performed at a distance of 1 m.
[0056] In FIG. 9, a guide index for aligning the subject's eye is displayed on the screen 210 of the display 5, superimposed on the captured image. In this embodiment, a guide frame GR is displayed as a guide index for aligning the subject's right eye, and a guide frame GL is displayed as a guide index for aligning the subject's left eye. For example, each of the guide frames GR and GL is rectangular. In addition, a guide line GC is displayed as a guide index for aligning the left and right centers of both the subject's eyes at the center of the guide frames GR and GL in the left and right direction. In addition, in the screen examples of FIG. 6 and FIG. 8 described above, the display of the guide frames GR and GL and the guide line GC is omitted for convenience of explanation.
[0057] Furthermore, the image captured by the imaging element 24 shows a bright spot KR of the corneal reflection of the right eye ER and a bright spot KL of the corneal reflection of the left eye EL, which are caused by the illumination optical system 30. The pupils EP around the bright spots KR and KL appear as black areas due to the low amount of reflected light. The examiner can determine the right eye ER and the left eye EL of the subject by checking the bright spots KR and KL and the pupils EP around them. The examiner then moves the optometry unit 2 in the X direction so that the right eye ER and the left eye EL of the subject enter the guide frames GR and GL, respectively, and are positioned evenly on the left and right sides with respect to the guide line GC.
[0058] Moreover, the examiner moves the optometry unit 2 in the Y direction so that the right eye ER and the left eye EL are positioned in the center of the guide frames GR and GL in the up-down direction.
[0059] Further, the alignment state of the face (eye) of the subject relative to the optometry unit 2 in the Z direction is detected by the distance detector 9, and the detection result is displayed on the screen 210. For example, the right column display unit 212 displays an indicator 213 indicating the distance of the optometry unit 2 relative to the subject's eye as a guide indicator for aligning the Z direction. For example, when the optometry unit 2 is closer to the subject's eye side relative to a predetermined working distance, the upper indicator 213a is increased. When the optometry unit 2 is farther from the subject's eye relative to a predetermined working distance, the lower indicator 213b is increased. The examiner moves the optometry unit 2 in the Z direction so that the indicators 213a and 213b decrease and disappear. Note that the guide display on the right column display unit 212 shown in FIG. 9 is merely an example, and various forms are possible for notifying the examiner of the alignment state in the Z direction. For example, an indicator indicating the detection result of the distance detector 9 may be superimposed on the captured image of the subject's face.
[0060] As described above, the examiner can align the optometry unit 2 with the subject's eye by moving the optometry unit 2 in the XYZ directions while observing the screen display of the display 5. In addition, the control unit 50 processes the captured image acquired by the imaging element 24 and detects the bright points KR and KL of the corneal reflection, thereby determining whether the alignment state in the XY directions is appropriate.
[0061] Returning to the explanation of the flowchart of FIG. 7, two bright points appear in the captured image, and it is determined whether or not there are bright points in each of the guide frames GR and GL (S4). Next, it is determined whether or not there is a black part (for example, a black part whose luminance is equal to or less than a predetermined value and spreads over a predetermined range based on the bright point) around each bright point that is regarded as a pupil (S5). If there is a black part that is regarded as a pupil around each bright point, it is determined that the subject's eye has been detected in the captured image. If the black part around the bright point is regarded as a pupil, the pupil diameter is obtained by image processing and used for measurement. Then, the bright points KR and KL of the left and right eyes are determined based on the positional relationship between the two bright points. That is, it is determined that the bright point in the guide frame GR is the bright point KR of the right eye ER, and the bright point in the guide frame GL is the bright point KL of the left eye ELR. Next, it is determined whether or not the two bright points KR and KL are within predetermined allowable ranges within the guide frames GR and GL, respectively (S6), thereby determining the alignment state in the XY directions.
[0062] The alignment state in the Z direction is determined by determining whether the Z position (distance in the Z direction) detected by the distance detector 9 is within a predetermined tolerance (S7). If the alignment states in the X, Y and Z directions are each within a predetermined tolerance, it is determined that the alignment is complete (S8).
[0063] When it is determined that the alignment in the XYZ directions is complete, the control unit 50 ends the blown-out highlight adjustment of the captured image (S9). That is, when it is determined that the alignment is complete, the illumination light amount and the gain of the image sensor 24, which were increased to make the captured image blown-out, are returned (reduced) to the predetermined levels during the inspection. In this embodiment, during the inspection, two of the four illumination light sources 32 located on the left or right side are turned on, and the gain of the image sensor 24 is returned to a level at which the captured image of the object located at a working distance of 1 m does not become "blown-out."
[0064] Furthermore, when alignment in the XYZ directions is completed, the control unit 50 automatically issues a trigger signal to start measurement, and measurement is performed (S10). Alternatively, instead of the measurement being performed automatically, a message indicating that alignment has been completed is displayed on the display 5, and the examiner who has confirmed this may operate an input switch for a measurement start signal provided on the operation unit 52, and the signal may be accepted, thereby performing the measurement.
[0065] When the measurement is performed, for example, the light sources 13a1, 13a2, and 13a3 of the measurement light source 13a in the first meridian direction shown in FIG. 3 are sequentially turned on. The measurement light from the measurement light source 13 is irradiated to the test eye and enters the pupil, and the reflected light reflected by the fundus is emitted from the pupil and photographed by the image sensor 24. Then, in synchronization with the sequential lighting of the measurement light source 13a, the photographed images photographed by the image sensor 24 are acquired and sequentially stored in the memory 54. Thereafter, similarly, each of the light sources of the measurement light sources 13b to 13h located in the other meridian directions is sequentially turned on, and in synchronization therewith, the photographed images photographed by the image sensor 24 are sequentially stored in the memory 54. When each photographed image is stored, the control unit 50 processes each image to determine the ocular refractive power of the left and right test eyes.
[0066] 10 is a diagram for explaining measurement of ocular refractive power by the photorefraction method. In the photorefraction method, ocular refractive power A is calculated by the following formula 1 based on the ratio R (B / 2r) of the pupil diameter 2r to the pupil radius B of the bright crescent K in the pupil.
[0067]
number
[0068] As described above, the ocular refractive power for each meridian direction of each light source is obtained, and the ocular refractive powers S (spherical power), C (cylindrical power), and A (cylindrical axis angle) of the left and right examinee's eyes are obtained. When the measurement is completed, the measurement result is output (S11). For example, the measurement result is displayed on the screen of the display 5.
[0069] If the measurement takes a long time, the alignment state in the X, Y and Z directions may go out of the allowable range during the measurement. In particular, the alignment is easily misaligned in a handheld ophthalmic device 1. If the alignment state in any of the X, Y and Z directions goes out of the allowable range, the measurement is interrupted, and at least one of the illumination light amount of the illumination optical system 30 and the gain of the image sensor 24 is increased again to perform an adjustment to "blow out highlights" in the captured image.
[0070] <Example of transformation> Although typical embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments shown here, and various modifications are possible.
[0071] For example, in the above description, the ophthalmic device is a handheld ophthalmic device, but the present invention is not limited to this. For example, the ophthalmic device may be a stationary type that is installed on a table. In this case, during alignment, the ophthalmic examination unit 2 is moved or guided so that the bright points KR and KL of the left and right eyes on the captured image captured by the image sensor 24 are positioned at predetermined positions.
[0072] In addition, in determining the degree of overexposure, the predetermined examination distance (working distance) at which the optometry unit 2 is located relative to the subject's eye is set to 1 m in the above embodiment, but is not limited to this. The predetermined examination distance may be set appropriately depending on the examination purpose of the ophthalmic apparatus.
[0073] In addition, the examination optical system for examining (including measuring) the subject's eye may be one for examining one eye. In this case, as exemplified in JP2022-80459A, in an ophthalmic apparatus having an imaging optical system for obtaining a magnified image of the anterior eye of one eye, the image sensor 24 for photographing the subject may be a face photographing unit provided separately from the optical system for obtaining a magnified image of the anterior eye.
[0074] Regarding the increase and decrease (increase / decrease) of the illumination light quantity of the illumination optical system, in addition to the increase and decrease (increase / decrease) of the number of illumination light sources turned on, the light quantity itself emitted from the illumination light quantity may be increased and decreased (increase / decrease). Alternatively, the illumination light quantity may be increased and decreased (increase / decrease) by using a light quantity attenuation filter arranged so as to be insertable into and removable from the optical path of the illumination optical system.
[0075] In addition, with regard to the end of the adjustment that causes blown-out highlights in the captured image (processing to return to a predetermined examination level), an example was described above in which the signal of the completion of alignment in the ZYZ directions (S8 in FIG. 7) is used as the trigger, but the trigger may also be a detection signal that indicates that the subject's eye has been detected in the captured image (S4 or S5 in FIG. 7), or the reception of a measurement start signal. Alternatively, if a switch operated by the examiner to end blown-out highlights in the captured image is provided in the operation unit 52, the reception of the operation signal may also be used as the trigger. The control means 50 also serves as a signal receiving means that receives each signal, and the alignment completion signal, the detection signal of the subject's eye, the measurement start signal, and the operation signal by the examiner are received by the control unit 50. [Explanation of symbols]
[0076] 1 Ophthalmology equipment 5. Display 10 Measurement optical system 10a Light projection optical system 10b Receiving optical system 24 Image sensor 30 Illumination optical system 32 Lighting source 40 Observation Optical System 50 Control section 52 Operation section 54 Memory
Claims
1. An ophthalmic device having an eye examination unit for examining the eye to be examined, A lighting means for irradiating the subject with illumination light, A means of capturing images by photographing the subject, A display means for displaying the captured image, Equipped with control means, The ophthalmic apparatus is characterized in that the control means increases at least one of the illumination light intensity of the illumination means and the gain of the imaging means, thereby causing the captured image displayed on the display means to be overexposed.
2. In the ophthalmic device according to claim 1, The control means is characterized by increasing at least one of the illumination light intensity and the gain applied during the examination of the eye to cause the captured image obtained when the eye examination unit is aligned with the eye to be examined to be overexposed.
3. In the ophthalmic device according to claim 1 or 2, The control means is characterized in that, during the examination of the eye under examination, it returns the illumination light intensity and the gain of the imaging means, which were increased to cause overexposure in the captured image, back to a predetermined examination level.
4. In the ophthalmic device according to claim 1 or 2, The system includes a receiving means for receiving at least one of the following signals: a detection signal for the eye to be examined; a completion signal indicating the completion of alignment of the eye examination unit with respect to the eye to be examined; an examination start signal for initiating the examination by the eye examination unit; and an operation signal operated by the examiner to terminate the overexposure of the captured image. The ophthalmic apparatus is characterized in that the control means returns the illumination light intensity and the gain of the imaging means, which were increased to cause overexposure in the captured image, to a predetermined examination level based on any signal received by the reception means.
5. An ophthalmic device control program that is executed in an ophthalmic device having an eye examination unit for examining an eye to be examined, which is executed by a control unit, The illumination step involves shining illumination light onto the subject, The imaging step involves capturing an image by photographing the subject with an imaging device, A display step of displaying the captured image, An ophthalmic device control program characterized by causing the ophthalmic device to perform a control step that causes the captured image displayed in the display step to be overexposed by increasing at least one of the illumination light intensity in the illumination step and the gain of the imaging means in the imaging step.