JP7714189B2 - ophthalmology equipment - Google Patents

Description

The present invention relates to an ophthalmic device.

Conventionally, ophthalmic devices are known that capture images of the ocular surface by irradiating the anterior segment of the subject's eye with light output from a light source. For example, the ophthalmic device described in Patent Document 1 discloses a configuration in which, when capturing images of the ocular surface, a ring-shaped light is irradiated onto the anterior segment of the subject's eye, and a configuration in which a fluorescent dye is instilled into the anterior segment of the subject's eye to perform fluorescent angiography.

JP 2019-84391 A

The ophthalmic device described in Patent Document 1 includes a means for capturing images of the ocular surface by irradiating a ring of light and a means for capturing images of the ocular surface using fluorescent angiography, but does not mention correlating the results of these two imaging methods. While dry eye symptoms can be identified using both imaging methods, imaging using ring of light and imaging using fluorescent angiography, the ophthalmic device described in Patent Document 1 may produce different measurement results regarding the condition (characteristics) of the ocular surface when images of the ocular surface are captured using different imaging methods. When images of the ocular surface of the same subject's eye are captured, it is preferable that the measurement results be the same regardless of the imaging method used.

The present invention was made in consideration of the above-mentioned problems, and aims to provide an ophthalmic device that can verify whether measurement results regarding the state (characteristics) of the ocular surface match when images of the ocular surface are captured using different imaging methods.

To achieve the above objective, the ophthalmic device includes an excitation light source that excites fluorescence from a fluorescent dye that has been instilled into the anterior segment of the subject's eye; a projection unit that projects multiple rings onto the anterior segment; an imaging optical system that images the anterior segment; and an imaging control unit that controls the imaging optical system to capture multiple first images that are images of the anterior segment illuminated by the excitation light source, and multiple second images that are images of the anterior segment projected by the projection unit.

In other words, when photographing the anterior segment of the subject's eye, the ophthalmic device controls photography by exciting fluorescence from a fluorescent dye and photography by projecting multiple rings onto the anterior segment of the subject's eye. This makes it possible, for example, to photograph an image of the ocular surface, to obtain images with the same characteristics (or the same phenomenon) from an image photographed by exciting fluorescence from a fluorescent dye and an image photographed using ring projection. Therefore, by comparing images photographed using different photographing methods, it is possible to verify whether the measurement results regarding the state of the ocular surface match.

FIG. 1 is a diagram illustrating an optical system according to the present embodiment. 1 is a block diagram illustrating the overall configuration of an ophthalmologic apparatus according to an embodiment of the present invention. FIG. 2 is a diagram schematically illustrating a photographing optical system. 4 is a flowchart illustrating an example of control according to the present embodiment. FIG. 10 is a diagram for explaining an example of image capture.

Here, the embodiments of the present invention will be described in the following order.
(1) Configuration of ophthalmic device:
(2) Shooting control processing and display processing:
(3) Other embodiments:

(1) Configuration of ophthalmic device:
An ophthalmic apparatus 1 according to one embodiment of the present invention includes a housing, and the housing includes an optical system and a control unit used for a plurality of types of measurements. In this embodiment, the ophthalmic apparatus 1 has at least a function of measuring the condition of the ocular surface and a function of displaying an image of the ocular surface of the subject's eye on a display unit.

Figure 1 is a diagram showing the optical system. Figure 2 is a block diagram illustrating the overall configuration of an ophthalmic apparatus 1 according to one embodiment of the present invention, including a control unit. Below, the ophthalmic apparatus 1 according to one embodiment of the present invention will be described using Figures 1 and 2. As shown in Figure 2, the ophthalmic apparatus 1 is composed of a head unit 602 in which an optical system for measuring the subject's eye is arranged, and a main body unit 601 equipped with a control unit 600 that controls switching of the optical system in the head unit 602, etc.

The main body 601 is equipped with an XYZ drive control unit 630 that moves the head unit 602 in the XYZ (left/right, up/down, front/back) directions relative to the main body 601, a joystick 640 that gives instructions such as adjusting the spatial position of the head unit 602, a display unit 650 that displays images of the subject's eye and measurement results of eye refractive power, a touch panel 660 that accepts instructions such as measurement items, a memory 670 used in the control processing of the control unit 600, and a fixation target control unit 680 that controls the fixation target unit.

(Configuration of optical system)
FIG. 1 shows the optical system of the ophthalmologic apparatus 1. The optical system includes an alignment optical system 100 including optical elements and the like on the optical path from a light source 101 to profile sensors 107 and 108. The optical system also includes a photographing optical system 300 including optical elements and the like on the optical path from light sources 301, 302, and 300a to a two-dimensional image sensor (CCD) 306. The optical system also includes a fixation optical system 400 including optical elements and the like on the optical path from a light source 514 to the subject's eye E via a relay lens 403, and an eye refractive power optical system 500 that detects the eye refractive power of the subject's eye. As shown in FIG. 1, each optical system is configured to share a portion of its components. In this embodiment, flat glasses 510 and 511 for measuring the anterior segment are placed in the observation port disposed in front of the subject's eye E.

(Alignment optical system 100)
In the alignment optical system 100, light from a light source 101 is reflected by a hot mirror 102, passes through an objective lens 103, is reflected by a hot mirror 104, and then passes through flat glasses 511 and 510 to be irradiated onto the cornea of the subject's eye E. In this embodiment, the light source 101 is an LED that outputs infrared light.

Light reflected by the cornea is received by lens 105 and profile sensor 107, and lens 106 and profile sensor 108, which are arranged symmetrically about the main optical axis O1. In this embodiment, the optical axis is a line segment connecting the centers of the lenses that make up the optical system, and each lens is arranged so that its thickness is rotationally invariant about the optical axis (same below).

In this embodiment, when the position of the subject's eye in the three-dimensional direction is appropriate, the position at which light reflected from the cornea is detected by profile sensors 107 and 108 is predetermined. The control unit 600 of the main body unit 601 moves the head unit 602 in the three-dimensional direction by issuing instructions to the XYZ drive control unit 630 so that the position at which light reflected from the cornea is detected by profile sensors 107 and 108 is the predetermined position. As a result, the head unit 602 and its internal optical system are aligned in the three-dimensional direction with respect to the subject's eye.

A variety of alignment techniques may be employed. For example, a configuration may be employed in which the examiner performs coarse alignment, and then the control unit 600 performs auto-alignment (fine adjustment). For coarse alignment, for example, the examiner visually recognizes a bright spot reflected from the cornea on the image of the subject's eye displayed on the display unit 650, and then uses the joystick 640 to move the head unit 602 so that the bright spot falls within a predetermined range. Of course, the alignment optical system is not limited to the example shown in FIG. 1. For example, a configuration in which the optical system performing alignment in the Z direction and the optical system performing alignment in the X and Y directions are separate optical systems (including partial overlap) may be employed.

(Fixation optical system 400)
When the fixation optical system 400 is used, light from the light source 514 is collimated by the collimator lens 513 and irradiated onto the fixation target 512. The light from the fixation target 512 then passes through the relay lens 403, reflects off the reflecting mirror 404, passes through the hot mirror 506, and is reflected off the dichroic mirror 304, passing along the main optical axis O1. The light then passes through the objective lens 303, the hot mirror 104, and the flat glasses 511 and 510 to form an image on the retina of the subject's eye E. Therefore, it is desirable that the positions of the fixation target 512 and the retina of the subject's eye are approximately conjugate. The subject's eye is fixated based on the fixation target 512, enabling measurement of eye characteristics such as ocular refractive power. The light source 514 is an LED that emits visible light visible to the subject (or examinee).

When measuring eye refractive power, the control unit 600 outputs a control instruction to the fixation target control unit 680. As a result, the fixation target control unit 680 controls the movement of the fixation target unit (fixation target 512, collimator lens 513, and light source 514) so that the fixation target and the retina of the subject's eye are approximately conjugate, causing the subject's eye to fixate. The control unit 600 then outputs a control instruction to the fixation target control unit 680, which moves the fixation target unit a predetermined distance to create a cloudy state and measures eye refractive power. For this reason, the fixation target unit can be moved back and forth along the optical axis in response to a signal from the control unit 600.

(Eye refractive power optical system 500)
When measuring eye refractive power, an eye refractive power optical system 500 is used. In this embodiment, the eye refractive power optical system 500 includes a light projecting optical system and a light receiving optical system. The eye refractive power optical system 500 includes optical elements and the like on an optical path from a light source 501 to the subject's eye E via a mirror 503 and a flat glass 511. Specifically, when eye refractive power is measured, measurement light (reflector light) from the light source 501 is collected by a condenser lens 502, reflected by a mirror 503, and passes through a hole in the center of a perforated mirror 504. The measurement light then passes through a parallel flat glass 505 serving as an optical deflection member disposed obliquely with respect to the optical axis O2, and is further reflected by a hot mirror 506 and a dichroic mirror 304 to pass through the main optical axis O1.

The plane-parallel glass 505 serving as an optical deflection member is installed so that the glass surface is tilted from a state parallel to the optical axis O2 by a predetermined angle relative to an axis perpendicular to the optical axis O2. Here, the angle of tilt is an angle smaller than 90 degrees (for example, 45 degrees) and may be determined according to the displacement between the measurement light and the optical axis. In this embodiment, the plane-parallel glass 505 is rotatable around the optical axis O2.

The measurement light reflected by the dichroic mirror 304 passes through the objective lens 303, the hot mirror 104, the flat glass 511, and the flat glass 510, and is irradiated onto the subject's eye E. When the measurement light reaches the subject's eye E, it changes depending on the refractive power of the subject's eye E and is reflected by the fundus of the subject's eye E. The reflected light from the fundus of the subject's eye E passes through the flat glass 510, the flat glass 511, the hot mirror 104, and the objective lens 303, in the reverse direction of the irradiation path. The reflected light then reflects off the dichroic mirror 304 and the hot mirror 506, travels along the optical axis O2, passes through the flat parallel glass 505, is reflected by the perforated mirror 504, and passes through the lens 507. The reflected light then passes through the ring lens 508 and forms a ring-shaped image (ring image) on the two-dimensional image sensor (CCD) 509.

The light source 501 uses infrared light with a longer wavelength than the alignment light (light source 101) and the measurement light (light sources 301 and 302). In this embodiment, an SLD (super luminescent diode) is used, but this is not limited to this, and an LED or laser diode (LD) used in the light source 101, etc. may also be used.

In this embodiment, the plane-parallel glass 505 is positioned conjugate to the pupil of the subject's eye E. Because the plane-parallel glass 505 has a refractive index greater than that of air, the direction of travel of light incident on the plane-parallel glass 505 changes, and the direction of travel of light output from the plane-parallel glass 505 also changes. As a result, the output light from the plane-parallel glass 505 is shifted a predetermined distance from the incident light and is parallel to the direction of travel of the incident light.

(Photographing optical system 300 when photographing using light sources 301 and 302)
The imaging optical system 300 may capture images using light sources 301 and 302, or may capture images using light source 300a (described later). First, we will explain the imaging optical system 300 that captures images using light sources 301 and 302. In this embodiment, the light sources 301 and 302 are blue LEDs that output blue visible light, and the wavelength range of the light output from the light sources 301 and 302 is, for example, 450 nm to 520 nm. This is because fluorescein, a fluorescent dye, is instilled into the subject's eye E, and the light sources 301 and 302 are irradiated onto the subject's eye E to excite the instilled fluorescent dye. That is, in this embodiment, the ocular surface can be observed by irradiating the anterior segment of the subject's eye E stained with fluorescein with the light sources 301 and 302. When the light sources 301 and 302 are irradiated onto the anterior segment stained with fluorescein, the fluorescein is excited and emits a green (fluorescent green) light.

When the imaging optical system 300 using light sources 301 and 302 is used to measure the condition (characteristics) of the ocular surface, light sources 301 and 302, arranged on the test eye side of the head unit 602, irradiate the anterior segment of the test eye E, including the cornea, with light. In this state, the objective lens 303, green filter 307, imaging lens 305, and two-dimensional image sensor 306 capture an image of the anterior segment of the test eye E, and the captured image of the anterior segment of the test eye E is displayed on the display unit 650. The green filter 307 selectively transmits the green light emitted by fluorescein (in other words, it cuts out other wavelengths). By transmitting fluorescently excited light through this green filter 307, a clearer captured image can be obtained.

In this embodiment, light source 301 and light source 302 output light with a shorter wavelength than light source 101. Therefore, hot mirror 104 transmits the light for measurement (measurement light) and reflects the light for alignment (alignment light, light from light source 101). Furthermore, dichroic mirror 304 has a reflection/transmission wavelength range set so that it transmits the measurement light. This allows the alignment light and measurement light to be appropriately divided, enabling each to be measured. Light sources 301 and 302 correspond to the "excitation light source" in this embodiment.

(Photographing optical system 300 when photographing using light source 300a)
Next, the imaging optical system 300 when imaging using the light source 300a will be described. As described above, the ophthalmologic apparatus 1 according to this embodiment is capable of performing ocular surface observation using the light source 300a. The light source 300a is attached to the tip of the observation port (the side of the subject's eye E). In this embodiment, the light source 300a is configured to project a ring-shaped pattern centered on the optical axis. In this embodiment, the ring-shaped pattern has multiple rings, each with a different diameter. Furthermore, when the distance between the subject's eye E and the light source 300a is constant, the larger the diameter of the ring, the wider the range of the area measurable by the ring. Of course, the light source 300a may have various configurations, such as a configuration including a single light source that outputs light from multiple rings of the ring-shaped pattern, or a configuration including multiple light sources corresponding to each of the multiple rings.

When the light source 300a is turned on, light is irradiated from multiple directions onto the subject's eye E and the ocular surface. In this embodiment, the light source 300a is a green LED. Furthermore, the light source 300a is not limited to a green LED and may be, for example, a white LED. That is, as described above, the imaging optical system 300 is provided with a green filter 307. Therefore, if the light source 300a is a green LED, a green image can be captured directly. On the other hand, if the light source 300a is a white LED, a green image can be captured by transmitting the light through the green filter 307. The fluorescein-stained anterior segment emits green light, and observation and imaging are performed using this green light. In this embodiment, the light used to observe and image the anterior segment illuminated in a ring shape by the light source 300a is also green. Therefore, in this embodiment, both the fluorescein-stained anterior segment and the ring-illuminated anterior segment are observed and imaged using green light. This allows the examiner to easily compare the two. If observation and measurement in the same color are not required, the light source 300a does not have to be green, and the green filter 307 may be omitted.

In this embodiment, when light output from light source 300a is irradiated onto the ocular surface, an image of the anterior segment of the subject's eye E is acquired by objective lens 303, green filter 307, imaging lens 305, and two-dimensional image sensor 306. It is sufficient that light source 300a can illuminate the area to be measured so that the area to be measured is captured by two-dimensional image sensor 306. Furthermore, the configuration that projects the ring-shaped pattern using light source 300a corresponds to the "projection unit" in this embodiment.

In this manner, in this embodiment, imaging of the ocular surface includes imaging by exciting fluorescein dropped into the subject's eye E with irradiation from the above-mentioned light sources 301 and 302, and imaging by projecting a ring onto the subject's eye E with irradiation from light source 300a. By controlling the on/off of these light sources 301 and 302 and light source 300a, it is possible to image the ocular surface using both imaging by exciting fluorescence and imaging by projecting a ring. In other words, in this embodiment, it is possible to image the ocular surface using multiple imaging modes.

Figure 3 is a schematic diagram showing an imaging optical system 300 including light sources 301, 302, and 300a. An image of the anterior segment of the subject's eye E is acquired by controlling light sources 301 and 302 or light source 300a and two-dimensional image sensor 306. That is, by turning on light sources 301 and 302 and turning off light source 300a using the control unit 600, light output from light sources 301 and 302 is irradiated onto the ocular surface, and the light reflected from the ocular surface passes through objective lens 303, green filter 307, and imaging lens 305 and is imaged on two-dimensional image sensor 306, thereby acquiring an image of the anterior segment of the subject's eye E. Meanwhile, the control unit 600 turns on the light source 300a and turns off the light sources 301 and 302, causing the light output from the light source 300a to be emitted in a ring shape onto the ocular surface, and the light reflected from the ocular surface passes through the objective lens 303, green filter 307, and imaging lens 305 to form an image on the two-dimensional image sensor 306, thereby acquiring an image of the anterior segment of the subject's eye E.

Note that the image of the anterior segment illuminated by light sources 301 and 302 that excite fluorescence corresponds to the "first captured image" in this embodiment, and the image of the anterior segment illuminated by the projection unit using light source 300a (i.e., ring photography) corresponds to the "second captured image" in this embodiment. As described above, this embodiment allows for the ocular surface to be photographed using multiple photography modes. Among the multiple photography modes, photography that excites fluorescence due to fluorescein staining corresponds to the "first photography mode" in this embodiment. In other words, the first captured image described above is photographed using the first photography mode. Among the multiple photography modes, photography that projects a ring onto the anterior segment corresponds to the "second photography mode" in this embodiment. In other words, the second captured image described above is photographed using the second photography mode. Among the multiple photography modes, photography that uses both photography that excites fluorescence due to fluorescein staining and photography that projects a ring onto the anterior segment corresponds to the "third photography mode" in this embodiment. In other words, the first and second captured images are captured in the third capture mode.

In addition, in this embodiment, the subject of the image captured by the imaging optical system 300 is a specific part of the subject's eye E. Specifically, the ocular surface is the subject of the image capture.

(2) Shooting control processing and display processing:
Next, we will explain the imaging control for capturing an image of the ocular surface and the control (display processing) for displaying the captured image on the display unit 650. The imaging control and image display processing are realized by the control unit 600 executing a control program (not shown). The control unit 600 that executes the control program functions as an imaging control unit 600a and a display processing unit 600b.

The imaging control unit 600a is a program module that controls the capture of a first image using an excitation light source that excites fluorescence from a fluorescent dye (fluorescein), and the capture of a second image using a ring-shaped light projected onto the anterior segment. In this embodiment, the imaging control unit 600a accepts selection from one of the following modes: a first imaging mode for capturing the first image, a second imaging mode for capturing the second image, or a third imaging mode for capturing both the first and second images, and performs imaging corresponding to the selected mode. Furthermore, when capturing images in each mode, the control unit 600 controls the on/off switching of the ring-shaped light source 300a and the fluorescence excitation light sources 301 and 302, as well as the two-dimensional image sensor 306. The display processing unit 600b is a program module that performs processing to display the images captured by the imaging control unit 600a on a display unit 650, such as a monitor.

Figure 4 is a flowchart illustrating an example of image capture control and image display processing. Here, we will explain typical ocular surface imaging, assuming the execution of the control in the flowchart of Figure 4 . Conventionally, ocular surface imaging has been performed using fluorescein staining. However, fluorescein staining requires the instillation of a staining solution into the subject's eye E. This can lead to side effects depending on the subject's eye condition and constitution, making it desirable to avoid the use of a staining solution. In such cases, ocular surface imaging has traditionally been performed using ring projection, which does not require a staining solution. However, compared to ring projection imaging, fluorescein staining imaging has more experience and proven success, and provides more reliable measurement results of ocular surface conditions (characteristics). However, when comparing fluorescein staining imaging with ring projection imaging, the results may not be the same even when measuring the same characteristic (or the same phenomenon). For example, the tear film break-up time (BUT) obtained using fluorescein staining imaging may not match the BUT obtained using ring projection. If the measurement results obtained by fluorescein staining and the measurement results obtained by ring projection do not match, there is a possibility that the reliability of the measurement results will be reduced if only one of the measurement results is used. Therefore, this embodiment is configured to make it possible to verify whether the measurement results obtained by fluorescein staining and the measurement results obtained by ring projection match.

The flowchart in Figure 4 will be explained in detail below. Note that the control shown in this flowchart is executed, for example, when the subject (or examinee) places their head and chin in the predetermined position of the ophthalmic device 1 and the examiner gives an instruction to start measuring the ocular surface.

The control unit 600 first checks the imaging mode (step S1). Specifically, it checks which imaging mode (imaging pattern) is being used. As described above, in this embodiment, the imaging modes include a first imaging mode in which fluorescein is instilled into the eye to excite fluorescence, a second imaging mode in which a ring of light is projected onto the anterior segment, and a third imaging mode that combines the ring imaging mode and the fluorescence excitation mode. In the first imaging mode, fluorescein is instilled into the subject's eye E, which may result in some side effects. Therefore, for subjects with relatively mild dry eye symptoms, it is preferable to use the second imaging mode to capture images of the ocular surface.

Therefore, in step S2, it is determined whether the shooting mode confirmed in step S1 is the second shooting mode. Note that, since steps S1 and S2 are substantially the same, steps S1 and S2 may be executed simultaneously, or step S1 may be omitted and control in this flowchart may begin from step S2.

If step S2 returns a positive result, i.e., if the imaging mode is determined to be the second imaging mode, alignment in the X, Y, and Z directions is performed (step S3). That is, the control unit 600 drives the head unit 602 in the three-dimensional X, Y, and Z directions to align (position) the head unit 602 with the subject's eye E. Specifically, the control unit 600 instructs the XYZ drive control unit 630 to move the head unit 602. At this time, the control unit 600 instructs the XYZ drive control unit 630 to move the head unit 602 a predetermined amount toward a predetermined reference position where the imaging optical system 300 can capture an image of the subject's eye E. When the head unit 602 is in the reference position, the position on the profile sensors 107 and 108 where reflected light from the cornea is received is predetermined. Therefore, the control unit 600 moves the head unit 602 a predetermined amount so that reflected light from the cornea moves toward the predetermined position.

Next, the control unit 600 turns on the light source 300a (step S4). That is, the control unit 600 turns on the light source 300a to capture an image of the ocular surface of the anterior segment, in other words, to project a ring of light onto the anterior segment.

Then, after turning on the light source 300a in step S4, the control unit 600 continuously captures images of the ocular surface (step S5). That is, the control unit 600 controls the lens drive unit in the imaging optical system 300 using the light source 300a, moves at least one of the objective lens 303 and the imaging lens 305 in the optical axis direction to bring the ocular surface into focus, and controls the two-dimensional image sensor 306 to capture images. Continuous capture can be achieved, for example, by having the examiner instruct the subject to close their eyelids and then open them for a predetermined period of time, during which time images of the ocular surface are continuously captured. Alternatively, the subject can be asked to open and close their eyelids (i.e., blink), during which time images of the ocular surface are continuously captured. In this embodiment, the frame rate of the two-dimensional image sensor 306 is 60 fps, meaning that the period for one frame is 1/60 seconds. As a result, images of the ocular surface are continuously captured.

Note that the in-focus state only needs to be achieved before the images are continuously captured. Various processes may be used to achieve the in-focus state. For example, the in-focus state may be achieved using a phase difference detection method based on the image capture results of the two-dimensional image sensor 306, or multiple images may be captured while changing the lens position, and the lens may be moved in advance to a position where an in-focus image will be captured. When image capture is performed, the control unit 600 records the image output from the two-dimensional image sensor 306 in memory 670.

The control unit 600 then displays the images captured in step S5 on the display unit 650 (step S6). That is, the control unit 600 uses the function of the display processing unit 600b to display the images captured in step S5 on the display unit 650. The captured images are displayed on the display unit 650 in chronological order. Alternatively, the images are played back and displayed as a video in chronological order. That is, the images displayed on the display unit 650 are either still images or video.

Next, we will explain how to photograph the ocular surface when the imaging mode is the first imaging mode. Specifically, if a negative determination is made in step S2 above, i.e., if it is determined that the imaging mode is not the second imaging mode, it is determined whether the imaging mode is the first imaging mode (step S10).

If step S10 returns a positive determination that the mode is either the photography mode or the first photography mode, the control unit 600 performs alignment in the X, Y, and Z directions (step S20). That is, the control unit 600 drives the head unit 602 in the three-dimensional X, Y, and Z directions to perform alignment (positioning) with the subject's eye E. The specific details of the alignment are the same as those for the alignment in the second photography mode described in step S3, so a detailed description will be omitted.

Next, the control unit 600 turns on the light sources 301 and 302 to excite fluorescein (a fluorescent dye) (step S30). That is, the control unit 600 turns on the light sources to capture an image of the ocular surface of the anterior segment.

After turning on the light sources 301 and 302 in step S30, the control unit 600 continuously captures images of the ocular surface (step S40). That is, the control unit 600 controls the lens drive unit in the imaging optical system 300 that uses the light sources 301 and 302, moves at least one of the objective lens 303 and the imaging lens 305 in the optical axis direction to bring the ocular surface into focus, and controls the two-dimensional image sensor 306 to capture images. Continuous capture can be achieved, for example, by having the examiner instruct the subject to close their eyelids and then open them for a predetermined period of time, during which time images of the ocular surface are continuously captured. Alternatively, the subject can be asked to open and close their eyelids (i.e., blink), during which time images of the ocular surface are continuously captured. In this embodiment, the frame rate of the two-dimensional image sensor 306 is 60 fps, meaning that the period for one frame is 1/60 seconds. As a result, images of the ocular surface are continuously captured.

Note that the in-focus state only needs to be achieved before the images are continuously captured. Various processes may be used to achieve the in-focus state. For example, the in-focus state may be achieved using a phase difference detection method based on the image capture results of the two-dimensional image sensor 306, or multiple images may be captured while changing the lens position, and the lens may be moved in advance to a position where an in-focus image will be captured. When image capture is performed, the control unit 600 records the image output from the two-dimensional image sensor 306 in memory 670.

The control unit 600 then displays the images captured in step S40 (step S50). That is, the control unit 600 uses the function of the display processing unit 600b to display the images captured in step S40 on the display unit 650. The captured images are displayed on the display unit 650 in chronological order. Alternatively, the images are displayed as a video in chronological order. That is, the images displayed on the display unit 650 are either still images or video.

Next, we will explain ocular surface imaging when the imaging mode is the third imaging mode, which consists of ring imaging and imaging using fluorescence excitation. Specifically, if a negative judgment is made in step S10 above, i.e., if it is determined that the imaging mode is not the first imaging mode, the imaging mode is neither the first imaging mode nor the second imaging mode, and therefore the third imaging mode is selected.

Therefore, as in the other modes described above, the control unit 600 performs alignment in the X, Y, and Z directions (step S100). That is, the control unit 600 drives the head unit 602 in the three-dimensional X, Y, and Z directions to perform alignment (positioning) with the subject's eye E. The specific details of the alignment are the same as those for the second imaging mode described in step S3, so a detailed description will be omitted.

Next, the control unit 600 coordinates and controls the first and second imaging modes. Specifically, in this embodiment, images of the ocular surface are captured alternately in the first and second imaging modes for each predetermined frame. More specifically, to capture images of the ocular surface in the second imaging mode, the control unit 600 turns on the light source 300a (i.e., the ring light source) (step S200) and continuously captures second captured images of the ocular surface (step S300). That is, before capturing images in step S300 and step S500 (described later), the control unit 600 controls the lens drive unit to move at least one of the objective lens 303 and the imaging lens 305 in the optical axis direction to bring the ocular surface into focus. The in-focus state only needs to be achieved before the images are continuously captured. Furthermore, various processes may be used to achieve the in-focus state. For example, this may be achieved using a phase difference detection method based on the image capture results of the two-dimensional image sensor 306. Alternatively, multiple images may be captured while changing the lens position, and the lens may be moved in advance to a position where an in-focus image is captured. Once the in-focus state is achieved, the control unit 600 controls the two-dimensional image sensor 306 to capture the image. The above-described lighting of the light source 300a and capturing of the image are performed for one frame at 60 fps. That is, in steps S200 and S300, the control unit 600 synchronizes the lighting of the light source 300a with the capturing of the image by the two-dimensional image sensor 306, and controls the light source 300a and the two-dimensional image sensor 306 so that the illumination switching and capturing are completed within a 1/60 second period. Note that if a negative determination is made in step S600 (described below) and control returns to step S200, the control content of step S200 is to turn off the light sources 301 and 302, which are fluorescence excitation light sources, and turn on the light source 300a.

Next, the control unit 600 turns off the light source 300a and turns on the light sources 301 and 302 (i.e., the fluorescence excitation light sources) to perform continuous imaging in the first imaging mode (step S400). That is, the control unit 600 controls the light source switching to switch the imaging mode. Then, after switching the light source, the control unit 600 captures the first captured image, which is an image of the ocular surface by fluorescence excitation (step S500). That is, the control unit 600 controls the two-dimensional image sensor 306 to perform imaging. Here too, the lighting of the light sources 301 and 302 and the imaging are performed for one frame at 60 fps. That is, in steps S400 and S500, the control unit 600 synchronizes the lighting of the light sources 301 and 302 with the imaging by the two-dimensional image sensor 306, and controls the light sources 301 and 302 and the two-dimensional image sensor 306 so that the lighting switching and imaging are completed within a period of 1/60 seconds.

In these imaging modes, the images taken in the second imaging mode and the first imaging mode are taken within a predetermined period of time after the subject's eye blinks. Here, it is sufficient to obtain an image from the predetermined period after a blink. For example, the image may be taken within a predetermined period of time after the subject opens their eyelids from a closed state, or imaging may be performed over a longer period of time, and an image taken within a predetermined period of time after the subject opens their eyelids from a closed state may be extracted. Furthermore, the eye is captured in the same state during these imaging modes. The interval between the image taken in the second imaging mode and the image taken in the first imaging mode is one frame period. In this embodiment, the two-dimensional image sensor 306 is an element capable of capturing images at 60 fps, as described above, and one frame period is 1/60 seconds. Therefore, the images taken in the second imaging mode and the first imaging mode are captured almost simultaneously. Therefore, it can be said that the subject's eye captured in the ring imaging image and the fluorescein-stained image is in the same state.

Figure 5 shows an example of alternating imaging using ring projection and fluorescein dye. In the example shown in Figure 5, imaging using ring projection and imaging using fluorescein dye are alternated every frame (i.e., every time). Note that in the example shown in Figure 5, imaging using ring projection and imaging using fluorescein dye are alternated every frame, i.e., every 1/60 seconds (in other words, a 1:1 ratio), but the imaging ratio is not limited to this. For example, imaging may be performed at a predetermined ratio, such as one imaging using ring projection and two imaging using fluorescein dye (a 1:2 ratio). In other words, imaging in the second imaging mode and the first imaging mode may be alternated a predetermined number of times within one second.

The control unit 600 then repeatedly performs imaging in the second imaging mode and the first imaging mode for a predetermined period of time. In other words, it alternates between group α in steps S200 and S300 and group β in steps S400 and S500, capturing images of the ocular surface of the anterior segment until the predetermined period of time has elapsed.

The control unit 600 then determines whether the predetermined time has elapsed and thus the capture of the ocular surface image is complete (step S600). If the determination in step S600 is negative, i.e., if it is determined that the predetermined time has not elapsed, the process returns to step S200, and steps S200 to S500 are repeatedly executed until the determination in step S600 is affirmative.

On the other hand, if step S600 returns a positive determination, i.e., if it is determined that the predetermined time has elapsed, the control unit 600 acquires images of the ocular surface taken in the second imaging mode in chronological order, and images of the ocular surface taken in the first imaging mode in chronological order (step S700). In other words, the control unit 600 acquires images taken in each imaging mode arranged in chronological order.

The control unit 600 then displays the captured images acquired in step S700 on the display unit 650 (step S800). That is, the control unit 600 uses the function of the display processing unit 600b to separate the images captured in the second capture mode and the images captured in the first mode and display them on the display unit 650. The captured images displayed on the display unit 650 are displayed as still images arranged in chronological order, or as videos played back in chronological order.

Next, the operation of this embodiment will be described. As described above, in this embodiment, when capturing images of the ocular surface in the anterior segment of the subject's eye E, multiple imaging modes are possible. Specifically, imaging can be performed using the first imaging mode, which is fluorescence excitation imaging, the second imaging mode, which is ring imaging, and the third imaging mode, which captures images using both ring imaging and fluorescence excitation imaging. In particular, by alternating between imaging using the third imaging mode, i.e., imaging using ring projection and imaging using fluorescein staining, it is possible to compare the same characteristics (or the same phenomenon) between the first image captured using fluorescein staining and the second image captured using ring projection. Therefore, it is possible to verify whether the measurement results obtained using fluorescein staining and the measurement results obtained using ring projection match.

If it is determined that the measurement results obtained by fluorescein staining and the measurement results obtained by ring projection match, then, in principle, diagnosis can be made based on the second captured image taken by ring projection. Even in this case, if a more detailed diagnosis is desired, diagnosis can be made based on the first captured image taken after fluorescein staining (same below).

On the other hand, if the measurement results obtained by fluorescein staining and the measurement results obtained by ring projection do not match, various operations can be performed. For example, if the imaging method that produced the most accurate measurement can be determined from the measurement results obtained by fluorescein staining and the measurement results obtained by ring projection, an operation can be performed that prioritizes the imaging method that can produce the most accurate measurement. Of course, even in this case, measurements can be performed using an imaging method that is not prioritized (same below).

In addition, conditions under which the measurement results obtained by fluorescein staining and the measurement results obtained by ring projection do not match may be identified. For example, if there are cases in which the measurement results match and cases in which they do not, for subjects with matching measurement results, the system can be operated so that, in principle, a diagnosis is made based on the second captured image taken by ring projection. If the measurement results do not match, the system can be operated so that an imaging method that can perform accurate measurements is given priority.

Furthermore, if there are cases where the measurement results match and cases where they do not, when examining symptoms where the measurement results match, in principle, the system can be operated so that diagnosis is made based on the second captured image captured by ring projection. When examining symptoms where the measurement results do not match, the system can be operated so that priority is given to an imaging method that enables accurate measurement. In any case, this embodiment enables accurate measurement of the ocular surface.

(3) Other embodiments:
The above embodiment is one example for carrying out the present invention, and various other embodiments can be adopted as long as the subject's eye can be photographed in the first and second photographing modes. For example, the ophthalmic apparatus is not limited to the configuration including the head unit and the main body unit as described above, and may include various other elements.

In the above-described embodiment, when imaging the ocular surface using the third imaging mode of ring projection imaging and fluorescein staining imaging, the control unit 600 is configured to control group α in steps S200 and S300 and then control group β in steps S400 and S500. However, the order of control of groups α and β may be reversed. In other words, control of group β in steps S400 and S500 (i.e., imaging with fluorescein staining) may be performed first, and then control of group α in steps S200 and S300 (i.e., imaging with ring projection) may be performed.

Furthermore, the image captured using ring projection and the image captured using fluorescein staining do not have to be images captured at a predetermined time after the same blink of the subject's eye E, but may be images captured at a predetermined time after different blinks. This is because, even if the images captured using ring projection and the image captured using fluorescein staining are taken after different blinks, the condition (characteristics) of the ocular surface of the same subject is thought to remain almost unchanged if these images are taken within an extremely short period of time (several seconds to several tens of seconds). In other words, even if the images captured using ring projection and the image captured using fluorescein staining are taken after different blinks, it can be said that the subject's eye captured in the image captured using ring projection and the subject's eye captured in the image captured using fluorescein staining are in the same condition.

Alternating a predetermined number of times between the first captured image (image captured using fluorescein staining) and the second captured image (image captured using ring projection) means switching between the first captured image and the second captured image one by one every 1/60 seconds, or alternatively, acquiring any predetermined number of first captured images (for example, two or three) and then acquiring any predetermined number of second captured images. In other words, the control of switching between light sources 301, 302 and light source 300a is not limited to every 1/60 seconds, and may be performed at any timing.

In addition, in the above embodiment, the imaging control unit 600a is configured to perform imaging in the first imaging mode, the second imaging mode, and the third imaging mode, and to control the light sources 301, 302 and the light source 300a during imaging. However, a control unit may be provided for each control operation. Therefore, for example, a separate light source control unit may be provided to control the on/off of the light source.

Furthermore, the technique of photographing specific areas of the subject's eye using the first, second, and third imaging modes can also be applied as a method invention. Furthermore, the above-described ophthalmic apparatus and method may be realized as a standalone apparatus or as part of an apparatus with multiple functions, and may include various aspects.

1...ophthalmic apparatus, 100...alignment optical system, 101...light source, 102...hot mirror, 103...objective lens, 104...hot mirror, 105...lens, 106...lens, 107...profile sensor, 108...profile sensor, 300...imaging optical system, 300a...light source, 301...light source, 302...light source, 303...objective lens, 304...dichroic mirror, 305...imaging lens, 306...two-dimensional image sensor, 307...green filter, 400...fixation optical system, 403...relay lens, 404...reflection mirror, 500...ocular refractive power optical system, 501 ...light source, 502...condensing lens, 503...mirror, 504...mirror, 505...parallel plane glass, 506...hot mirror, 507...lens, 508...ring lens, 509...two-dimensional image sensor, 510...plane glass, 511...plane glass, 512...fixation target, 513...collimator lens, 514...light source, 600...control unit, 600a...imaging control unit, 600b...display processing unit, 601...main body unit, 602...head unit, 630...XYZ drive control unit, 640...joystick, 650...display unit, 660...touch panel, 670...memory, 680...fixation target control unit.

Claims (8)

an excitation light source that excites fluorescence from a fluorescent dye that has been instilled into the anterior segment of the subject's eye;
a projection unit that projects a plurality of rings onto the anterior segment;
an imaging optical system for imaging the anterior segment of the eye;
an imaging control unit that controls the imaging optical system to capture a plurality of first captured images, which are images of the anterior eye segment illuminated by the excitation light source, and to capture a plurality of second captured images, which are images of the anterior eye segment projected by the projection unit;
the first captured image and the second captured image are images captured during a predetermined period after the same blink of the subject's eye.
Ophthalmology equipment. an excitation light source that excites fluorescence from a fluorescent dye that has been instilled into the anterior segment of the subject's eye;
a projection unit that projects a plurality of rings onto the anterior segment;
an imaging optical system for imaging the anterior segment of the eye;
an imaging control unit that controls the imaging optical system to capture a plurality of first captured images, which are images of the anterior eye segment illuminated by the excitation light source, and to capture a plurality of second captured images, which are images of the anterior eye segment projected by the projection unit;
The imaging control unit
accepts a selection from a first photographing mode in which the first photographed images are continuously photographed, a second photographing mode in which the second photographed images are continuously photographed, and a third photographing mode in which the first photographed images and the second photographed images are continuously photographed, and performs photographing corresponding to the selected mode;
Ophthalmology equipment. the first captured image and the second captured image are images captured during a predetermined period after another blink of the subject's eye.
The ophthalmic apparatus according to claim 2 . The imaging control unit
accepts a selection from a first photographing mode in which the first photographed images are continuously photographed, a second photographing mode in which the second photographed images are continuously photographed, and a third photographing mode in which the first photographed images and the second photographed images are continuously photographed, and performs photographing corresponding to the selected mode;
The ophthalmic device according to claim 1 . The imaging control unit
The first captured image and the second captured image are alternately captured every predetermined number of times.
The ophthalmic apparatus according to any one of claims 1 to 4. a display processing unit that displays the first captured image and the second captured image separately;
The ophthalmic apparatus according to any one of claims 1 to 5. the display processing unit displays at least one of the plurality of first captured images that have been successively captured and the plurality of second captured images that have been successively captured in a time series.
The ophthalmic device according to claim 6 . the display processing unit plays back and displays at least one of the plurality of first captured images that are continuously captured and the plurality of second captured images that are continuously captured in chronological order as a moving image.
The ophthalmic device according to claim 6 .