Ophthalmologic apparatus, control method of ophthalmologic apparatus, and program

Abstract

To provide an inexpensive ophthalmologic apparatus capable of diagnosing an angle or an anterior chamber depth of a subject eye.SOLUTION: An ophthalmologic apparatus of the present disclosure includes: imaging means that images a subject eye; drive means that performs drive of changing a position of the imaging means such that a distance between the imaging means and the subject eye is a predetermined distance by using a fundus image captured by the imaging means; and estimation means that estimates information regarding an angle of the subject eye by using an anterior eye image captured by the imaging means in the predetermined distance.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to an ophthalmic device, a control method for an ophthalmic device, and a program.

Background Art

[0002] As risk factors for glaucoma, a narrow angle of the anterior chamber and a shallow anterior chamber are known. A narrow angle of the anterior chamber refers to a state where the angle of the eye is narrow. Also, a shallow anterior chamber refers to a state where the depth of the anterior chamber is shallow due to a narrow angle of the anterior chamber. In the case of a narrow angle of the anterior chamber or a shallow anterior chamber, it is known that the risk of angle-closure glaucoma increases. As devices for diagnosing the size of the angle of the anterior chamber, a gonioscope, a slit lamp microscope, an optical coherence tomography system for the anterior segment of the eye (anterior segment OCT), and the like are used.

[0003] Here, Patent Document 1 describes a technique related to an anterior segment OCT capable of measuring the size of the angle of the anterior chamber.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, since an anterior segment OCT and a slit lamp microscope are, for example, expensive, it is difficult to widely spread them for uses intended for screening such as health checkups.

[0006] Therefore, an object of the present disclosure is to provide an inexpensive ophthalmic device capable of diagnosing the angle of the anterior chamber or the depth of the anterior chamber of an eye to be examined.

Means for Solving the Problems

[0007] The ophthalmic device of the present disclosure includes imaging means for imaging an eye to be examined, driving means for driving to change the position of the imaging means so that the imaging means and the eye to be examined are at a predetermined distance using a fundus image captured by the imaging means, and estimation means for estimating information regarding the corner of the eye to be examined using an anterior eye image captured by the imaging means at the predetermined distance.

Effect of the Invention

[0008] According to the present disclosure, it is possible to provide an inexpensive ophthalmic device capable of diagnosing the corner of the eye to be examined or the anterior chamber depth.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0010] Hereinafter, exemplary embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions of the components, etc. described in the following embodiments are arbitrary and can be changed according to the configuration of the device to which the present disclosure is applied or various conditions. Also, in the drawings, the same reference numerals are used between the drawings to indicate elements that are the same or functionally similar.

[0011] (Embodiment 1) Hereinafter, as an example of the ophthalmic apparatus and its control method according to Embodiment 1 of the present disclosure, a fundus camera apparatus and its control method will be described. The fundus camera apparatus described in this embodiment estimates the corners of the eye to be examined after aligning (positioning) the optical head unit with the eye to be examined and before performing imaging of the fundus.

[0012] <Schematic configuration of the apparatus> The schematic configuration of the fundus camera apparatus according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a side view showing an example of the schematic configuration of the fundus camera apparatus according to this embodiment. The fundus camera apparatus is provided with an imaging unit 10, a control unit 20, a display unit 40, and an input unit 50. The imaging unit 10 is provided with an optical head unit 100, a stage unit 150, a base unit 190, and a face support unit 160.

[0013] The optical head unit 100 irradiates light to the eye to be examined and detects the return light from the eye to be examined, and includes a measurement optical system for taking a front-eye observation image and a fundus image. The stage unit 150 includes driving means (such as a motor) (not shown), and the optical head unit 100 can be moved in the XYZ directions in the figure using the driving means. Note that the optical head unit 100 is an example of imaging means for imaging the eye to be examined. Also, the stage unit 150 is an example of driving means for driving to change the position of the imaging means.

[0014] The face support unit 160 is a jaw rest that can promote fixation of the eye (eye to be examined) of the subject by fixing the jaw and forehead of the subject. Also, the face support unit 160 is provided with a driving member such as a motor (not shown), and the driving member can move the face support unit 160 in the Y direction in the figure.

[0015] The control unit 20 is connected to the imaging unit 10, the display unit 40, and the input unit 50, and can control these. The control unit 20 can, for example, control the movement of the stage unit 150 and perform alignment of the optical head unit 100 with respect to the eye to be examined. Also, the control unit 20 can generate a front-eye observation image, a fundus observation image, and a fundus imaging image based on the data acquired by the imaging unit 10.

[0016] The control unit 20 may be configured using a general computer (information processing device) including a processor and a memory, or may be configured as a computer dedicated to the fundus camera device. Further, the control unit 20 may be a separate (external) computer communicably connected to the imaging unit 10, or may be a computer built into the imaging unit 10. Here, communicable includes not only direct communication between devices but also communication via other devices. Also, the control unit 20 may be, for example, a personal computer, and a desktop PC, a notebook PC, or a tablet PC (portable information terminal) or the like may be used. Note that not all of the configurations shown in FIG. 1 need to be built into one device. A part of the connection of the configuration shown in FIG. 1 (for example, the connection between the control unit 20 and the imaging unit 10) may be realized as a wired or wireless network connection, and the configuration shown in FIG. 1 may function as one ophthalmic system.

[0017] Also, the control unit 20 has a display control unit 60. The display control unit 60 performs control to display, for example, a front-eye image or a fundus image captured by the imaging unit 10 on the display unit 40. Note that the display control unit 60 is an example of display control means.

[0018] The display unit 40 is, for example, a liquid crystal display. The display unit 40 displays various information such as subject information, various images, and a mouse cursor or the like according to the operation of the input unit 50 under the control of the control unit 20. The input unit 50 is an input device for giving an instruction to the control unit 20. The input unit 50 is, for example, a keyboard or a mouse. Note that the display unit 40 may be a touch panel type display. When the display unit 40 is a touch panel type display, the display unit 40 is also used as the input unit 50.

[0019] In the present embodiment, the imaging unit 10, the control unit 20, the display unit 40, and the input unit 50 are each separately configured, but some or all of these may be integrally configured. Also, other imaging devices, storage devices, etc. (not shown) may be connected to the control unit 20.

[0020] <Configuration of the measurement optical system> Next, with reference to FIG. 2, a configuration example of the measurement optical system of the present embodiment will be described.

[0021] <Configuration of the optical head unit 100> The optical head unit 100 is provided with an optical system for photographing an image of the anterior eye part Ea and the fundus Ef of the eye to be examined E. Hereinafter, various optical systems arranged in the optical head unit 100 will be described.

[0022] In the optical head unit 100, an objective lens 101 is arranged facing the eye to be examined E. On the optical axis L1 of the objective lens 101, a first dichroic mirror 103 that functions as an optical path branching unit is arranged. By the first dichroic mirror 103, the optical path of the anterior eye observation system (optical axis L2) and the optical path of the fundus imaging system (optical axis L3) are branched for each wavelength band.

[0023] On the optical axis L2 in the reflection direction of the first dichroic mirror 103, a lens 120, a prism 121, a diaphragm 122, a lens 123, and an image sensor 124 are arranged. The image sensor 124 is a monochromatic two-dimensional sensor having sensitivity in the infrared region. An anterior eye observation system for observing the anterior eye part Ea is configured by these optical members and the like arranged on the optical axis L2.

[0024] The image sensor 124 is connected to the control unit 20. The image sensor 124 sends a signal corresponding to the detected light to the control unit 20. The control unit 20 generates an anterior eye observation image based on the signal received from the image sensor 124 and displays it on the display unit 40. In addition, an anterior eye observation light source 125 arranged near the objective lens 101 illuminates the anterior eye part Ea of the eye to be examined E. Further, the prism 121 is divided into upper and lower parts and is configured to refract light beams in opposite directions to each other. By this prism 121, the anterior eye observation image is split according to the operating distance between the eye to be examined and the apparatus.

[0025] On the optical axis L3 in the transmission direction of the first dichroic mirror 103, a perforated mirror 131, a photographing aperture 132, a focus lens 133, an imaging lens 134, a second dichroic mirror 135, and an image sensor 136 are arranged. The perforated mirror 131 has an opening at the center. The focus lens 133 is held so as to be movable in the optical axis direction indicated by the arrow in the figure by a driving unit such as a motor (not shown) controlled by the control unit 20. By moving the focus lens 133 on the optical axis L3, the focus of the fundus imaging system can be adjusted. The optical path on the optical axis L3 is branched by the second dichroic mirror 135 into an optical path leading to the image sensor 136 and an optical path leading to the fixation lamp 137 for each wavelength band.

[0026] The image sensor 136 is a two-dimensional sensor for fundus images that has sensitivity to visible light and infrared light and combines observation and still image photography. The image sensor 136 sends a signal corresponding to the detected light to the control unit 20. The control unit 20 generates a fundus observation image or a fundus photography image based on the signal received from the image sensor 136 and displays it on the display unit 40. The fixation lamp 137 emits visible light to prompt the subject's fixation. Note that the fixation lamp 137 may be provided with a diaphragm (not shown) for cutting the light beam necessary for fundus photography.

[0027] On the optical axis L4 in the reflection direction of the perforated mirror 131, a corneal baffle 140, a relay lens 141, a focus target unit 142, a lens 143, and a ring slit 144 are arranged in this order. The corneal baffle 140 has a light-shielding point at the center. The ring slit 144 has a ring-shaped slit opening. Also, on the optical axis L4, there is a lens baffle 145 as a light-shielding member having a light-shielding point. Further, on the optical axis L4, a dichroic mirror 146 having the property of transmitting infrared light and reflecting visible light is arranged.

[0028] The focus target unit 142 is an optical member that provides a focusing target using the focus lens 133. In this embodiment, as an example of the target, a split bright line is irradiated. The focus target unit 142 according to this embodiment has a split target member that can move along the optical axis L4 in conjunction with the focus lens 133. Further, the split target member is configured to be insertable and removable with respect to the optical path of the optical axis L4 by a drive unit such as a motor (not shown) controlled by the control unit 20.

[0029] The split bright line irradiated by the focus target unit 142 passes through the relay lens 141 and is reflected by the perforated mirror 131 toward the first dichroic mirror 103. The split bright line reflected by the perforated mirror 131 is projected onto the fundus Ef of the eye E to be examined through the first dichroic mirror 103 and the objective lens 101. The control unit 20 can calculate the amount of focus deviation by detecting the position of the split bright line from the fundus observation image.

[0030] A condenser lens 147 and a white LED light source 148 are arranged in the reflection direction of the dichroic mirror 146. The white LED light source 148 is a photographing light source in which a plurality of white LEDs that emit visible pulsed light are arranged. A condenser lens 149 and an infrared LED light source 150 are arranged in the transmission direction of the dichroic mirror 146. The infrared LED light source 150 is an observation light source in which a plurality of infrared LEDs that emit infrared steady light are arranged. Note that the white LED light source 148 and the infrared LED light source 150 are controlled to be driven by the control unit 20. Note that the infrared LED light source 150 is an example of the illumination means. Further, the white LED light source 148 is an example of the second illumination means that illuminates the second illumination light.

[0031] The illumination optical system for illuminating the fundus Ef is constituted by the dichroic mirror 146, the optical members therebetween, and the condenser lenses 147 and 149. Through the illumination optical system, the fundus Ef of the subject eye E can be illuminated by the light of the white LED light source 148 or the infrared LED light source 150. Further, the fundus imaging system is constituted by the optical members on the optical axes L3 and L4.

[0032] <Display unit> FIG. 3 is a diagram showing an example of the content displayed on the display unit 40. On the display unit 40, an anterior eye observation image 300, a fundus observation image 301, a fundus photographed image 302, and a corner warning mark 303 are displayed. The anterior eye observation image 300 is an image generated by processing the output of the image sensor 124. The anterior eye observation image 300 is an image in which the pupil of the subject eye is split according to the operating distance between the subject eye and the apparatus. This is due to the prism effect of the prism 121. The prism 121 is arranged so that the upper and lower parts of the pupil coincide when the operating distance between the subject eye and the apparatus becomes a distance suitable for fundus camera photography. Therefore, the alignment state in the Z direction between the subject eye and the apparatus can be determined from the split direction and split amount of the pupil. The alignment states in the X and Y directions can be determined from the position of the pupil center of the subject eye in the anterior eye observation image 300. If the pupil center is away from the center of the image, it can be determined that the alignment state in the XY direction is incorrect. In the illustrated anterior eye observation image 300, the pupil of the subject eye is split, and the upper half is shifted to the right of the lower half. This indicates that the operating distance between the subject eye and the apparatus is too far. Also, the pupil center is closer to the left of the image. This indicates that the alignment state in the X direction is shifted. The height of the pupil center is approximately at the center of the image. This indicates that the alignment state in the Y direction is appropriate.

[0033] The fundus observation image 301 is a monochrome image generated by processing the output of the image sensor 136. It is an image for observing the state of the fundus illuminated by the infrared LED light source 150. The fundus photograph image 302 is a color image generated by processing the output of the image sensor 136. It is an image of the fundus obtained by the image sensor 136 simultaneously with the pulsed emission of the white LED light source 148.

[0034] The corner warning mark 303 is a mark that notifies that the corner of the eye to be examined is smaller compared to the corner of a normal eye. This mark is displayed when it is estimated by the method described later that the corner of the eye to be examined is smaller compared to the corner of a normal eye. It is a mark that images the state of the anterior segment with a narrow angle of the anterior chamber. Note that the corner warning mark 303 is an example of information regarding the corner of the eye. Note that the corner warning mark 303 is not limited to that shown in FIG. 3. The corner warning mark 303 may be, for example, a character string such as "There may be a narrow angle of the anterior chamber".

[0035] Also, in FIG. 3, an example is shown in which the corner warning mark 303 is displayed on the display unit 4 when the corner of the eye to be examined is small. However, when the corner of the eye to be examined is normal, a mark or character string indicating normality may be displayed on the display unit 4.

[0036] <Flare> Next, referring to FIG. 4, the flare (corneal reflection image) in the fundus image will be described.

[0037] Figs. 4(a), (b), and (c) show a state where the distance between the device and the eye to be examined is suitable for fundus photography. Fig. 4(a) is a diagram showing the projection light beam onto the fundus and the reflected light beam from the fundus at that time. Fig. 4(b) is an enlarged view of the vicinity of the anterior segment of Fig. 4(a). The projection light beam 401 is a light beam for illuminating the eye to be examined by the infrared LED light source 150 or the white LED light source 148. The conjugate plane 402 is the conjugate plane of the corneal baffle 140. The corneal baffle 140 has a light-shielding point at the center. Since the light beam irradiated onto the center of the cornea is shielded at this light-shielding point, the projection light beam 401 is irradiated onto the fundus through the peripheral part of the cornea. The reflected light beam 403 is a light beam that the projection light beam 401 is reflected from the fundus of the eye to be examined and returns to the device. Since the projection light beam 401 and the reflected light beam 403 are separated on the cornea of the eye to be examined, the unnecessary light reflected by the projection light beam 401 on the cornea does not enter the light receiving system of the device. Therefore, if the distance between the device and the eye to be examined is appropriate, a fundus image without artifacts can be obtained as shown in Fig. 4(c). Note that the distance suitable for fundus photography is an example of the second distance.

[0038] On the other hand, Figs. 4(d), (e), and (f) show a state where the distance between the device and the eye to be examined is closer than the distance suitable for fundus photography. Fig. 4(d) is a diagram showing the projection light beam onto the fundus and the reflected light beam from the fundus at that time. Fig. 4(e) is an enlarged view of the vicinity of the anterior segment of Fig. 4(d). The projection light beam 411 is a light beam for illuminating the eye to be examined by the infrared LED light source 150 or the white LED light source 148. The conjugate plane 412 is the conjugate plane of the corneal baffle 140. Since the operating distance is too close, the cornea of the eye to be examined is located closer to the device than the conjugate plane 412. The reflected light beam 413 is a light beam that the projection light beam 411 is reflected from the fundus of the eye to be examined and returns to the device. However, in Fig. 4(e), since the distance between the device and the eye to be examined is close, the projection light beam 411 and the reflected light beam 413 partially overlap on the cornea of the eye to be examined. In such a case, a part of the projection light beam 411 is reflected by the cornea and reaches the image sensor 136 along the same optical path as the reflected light beam 413 as unnecessary light. Then, this unnecessary light is imaged as an artifact called flare (corneal reflection image) in the fundus image. Fig. 4(f) shows a fundus image in which flare (corneal reflection image) is imaged. A bright flare 414 is circularly imaged around the fundus of the eye to be examined.

[0039] Here, the flare generated by the corneal reflex, i.e., the corneal flare, has been described. However, apart from the corneal flare, there is also a lens flare due to the reflection on the back surface of the lens. The lens flare is likely to occur when the device and the eye to be examined are too far apart. Therefore, in order to obtain a good fundus image without flare, it is important to appropriately maintain the distance so that the distance between the eye to be examined and the device is not too close and not too far. When flare occurs in the fundus image, it can be seen that the distance between the device and the eye to be examined is not appropriate. In addition, if the type of flare generated (corneal flare or lens flare) and the degree (for example, the area of the flare 414 captured in the fundus image) are known, the distance between the eye to be examined and the device can be estimated.

[0040] <Imaging flow> Next, the imaging flow of this embodiment will be described with reference to FIG. 5.

[0041] First, in step S501, the control unit 20 aligns the optical head unit 100 and the eye to be examined E. The control unit 20 obtains the amount of positional deviation in the XYZ directions between the optical head unit 100 and the eye to be examined E based on the pre-eye observation image acquired by the image sensor 124. Then, the control unit 20 moves the optical head unit 100 by driving the stage unit 150 according to the amount of positional deviation. The control unit 20 completes the anterior eye alignment when the amount of positional deviation becomes less than a predetermined value.

[0042] In step S502, the control unit 20 performs corner estimation by the method described later.

[0043] In step S503, the control unit 20 estimates whether the corner is narrow based on the estimation result of step S502. If it is estimated in step S502 that the corner is narrow (YES), the control unit 20 displays a corner warning mark 303 on the display unit 40 in step S504. If it is not estimated in step S502 that the corner is narrow (NO), the control unit 20 does not display the corner warning mark 303.

[0044] Next, in step S505, the control unit 20 performs focus adjustment. The control unit 20 calculates the amount of focus deviation by detecting the position of the split bright line from the fundus observation image, and drives the focus lens 133 based on the calculated amount of focus deviation.

[0045] Next, in step S506, the control unit 20 performs light amount adjustment. Since there are individual differences in the reflectance of the fundus of the eye to be examined, even if the light amount of the infrared LED light source 150 is the same, the brightness of the fundus observation image will not be the same. Therefore, the control unit 20 adjusts the light amount of the infrared LED light source 150 so that the brightness of the fundus observation image falls within a predetermined range.

[0046] Finally, in step S507, the control unit 20 performs fundus photography. The control unit 20 causes the white LED light source 148 to emit light in pulses and simultaneously acquires a fundus photography image with the image sensor 136. The lighting time and light amount of the white LED light source 148 at this time are determined based on the light amount of the infrared LED light source 150 adjusted in step S506.

[0047] Note that the imaging flow described so far is merely an example. The order of each step may be different, and the specific content of the processing in each step may also be different. Also, there may be additional processing other than the processing described so far. However, generally, the cornea angle tends to become narrower as the pupil diameter becomes larger, so it is advisable to perform cornea angle estimation before the pupil constricts due to fundus photography. Also, in this embodiment, a cornea angle warning mark is displayed to notify the examiner, but other methods may be used for notification. Other methods may include, for example, displaying text or changing the background color. Also, instead of display, notification may be made by sounding a warning tone or recording in the meta information of the fundus image file.

[0048] Next, with reference to FIG. 6, the concept of cornea angle estimation in this embodiment will be described.

[0049] FIG. 6(a) is a schematic diagram of an eye under examination with a normal-sized corneal angle. The angle formed by the peripheral part 601 of the cornea and the iris 602 is the corneal angle. FIG. 6(b) is a schematic diagram of an eye under examination with a small corneal angle. The angle (corneal angle) formed by the peripheral part 611 of the cornea and the iris 612 is smaller than the corneal angle in FIG. 6(a).

[0050] FIG. 6(c) is an image for fundus observation of the eye under examination shown in FIG. 6(a). FIG. 6(d) is an image for fundus observation of the eye under examination shown in FIG. 6(b). The corneal flare 603 is formed by the light reflected by the projection light beam at the peripheral part 601 of the cornea. The corneal flare 613 is formed by the light reflected by the projection light beam at the peripheral part 611 of the cornea. Since the corneal flares in FIGS. 6(c) and 6(d) are of the same degree, it is presumed that the distances between the device and the peripheral part of the cornea in FIGS. 6(c) and 6(d) are about the same.

[0051] FIG. 6(e) is an image for anterior eye observation of the eye under examination shown in FIG. 6(a). FIG. 6(f) is an image for anterior eye observation of the eye under examination shown in FIG. 6(b). These are acquired at the same timing as the images for fundus observation in FIGS. 6(c) and 6(d). The iris 614 and the iris 604 are split in the same direction (left - right direction), but the split amount of the iris 614 is larger than that of the iris 604. This indicates that the distance between the device and the iris of the eye under examination in FIG. 6(f) is smaller than that in FIG. 6(e). This indicates that the iris 612 protrudes more toward the cornea side than the iris 602 (the distance between the iris and the cornea is shorter). Therefore, when the split amount of the iris is larger than a preset value as in FIG. 6(f), the eye under examination shown in FIG. 6(b) is presumed to have a small corneal angle. Note that for the estimation of the corneal angle, the split amount of the pupil may be used instead of the split amount of the iris. Specifically, when the upper half of the pupil is split to the left side compared to the lower half and the split amount of the pupil is equal to or greater than a preset value, it is presumed that the corneal angle is small. The preset value may be pre - set in the device. Alternatively, the preset value may be settable by the examiner or doctor.

[0052] As described above, it is possible to estimate whether the angle is small based on the anterior eye observation image. Here, the concept of angle estimation has been described, but instead of the angle, the anterior chamber depth may be estimated. The anterior chamber depth of the eye to be examined shown in Fig. 6(b) is shallower than the anterior chamber depth of the eye to be examined shown in Fig. 6(a). Therefore, by using the same concept as angle estimation, it is possible to estimate whether the anterior chamber depth is shallow based on the anterior eye observation image.

[0053] Next, with reference to Fig. 7, the flow of angle estimation in the present embodiment will be described.

[0054] Fig. 7 illustrates the details of step S502 in Fig. 5. First, in step S701, the control unit 20 drives the optical head unit 100 to the angle estimation position. The angle estimation position is a position where the optical head unit 100 and the eye to be examined are at a predetermined distance, specifically, a position where corneal flare as shown in Figs. 6(c) and 6(d) occurs in the fundus observation image. The driving to the angle estimation position will be specifically described. The control unit 20 performs anterior eye tracking based on the anterior eye observation image in the XY directions. That is, the control unit 20 continuously drives the optical head unit 100 in the direction so as to maintain a state where the amount of positional deviation in the XY directions is less than a predetermined value. Regarding the Z direction, the control unit 20 drives the optical head unit 100 and approaches it until corneal flare occurs in the fundus observation image. Then, the control unit 20 monitors the luminance of the peripheral part of the fundus observation image, and determines that corneal flare has occurred when the area of the region (bright region) where the luminance is equal to or higher than the threshold value becomes a certain value or more. Generally, since corneal flare has a higher luminance than lens flare, the control unit 20 can surely detect only corneal flare by setting the luminance threshold value to a value higher than the luminance of lens flare.

[0055] Next, in step S702, the control unit 20 obtains the split direction and split amount of the pupil by analyzing the anterior eye observation image, and compares them with a predetermined value. Note that in S702, the control unit 20 may perform angle estimation based on the split amount of the iris instead of the split amount of the pupil.

[0056] When the upper half of the pupil is split to the left compared to the lower half and the split amount is equal to or greater than a predetermined value (S702 - YES), the control unit 20 estimates that the corneal angle is small (S703). When the split amount is less than the predetermined value (S702 - NO), the control unit 20 estimates that the corneal angle is normal (S704).

[0057] Finally, in step S705, the control unit 20 drives the optical head unit 100 to the fundus imaging position. Specifically, the control unit 20 performs anterior eye alignment similar to step S501 in FIG. 5 based on the anterior eye observation image. As a result, the split amounts of the pupil and the iris return to approximately 0.

[0058] By using the above method, the fundus camera device in the present embodiment can estimate the corneal angle of the eye to be examined based on the anterior eye observation image. Further, the fundus camera device in the present embodiment can issue a warning to the examiner when it is estimated that the corneal angle is small.

[0059] Furthermore, in addition to the above method, improvements may be made to improve the estimation accuracy of the corneal angle and the anterior chamber depth. For example, information about the cornea such as keratoconus and refractive corneal surgery (LASIK), and information about the anterior eye such as the presence or absence of an intraocular lens (IOL) may be input to the control unit 20 before estimating the corneal angle as part of the patient information. Since the information about the anterior eye is related to the corneal angle and the anterior chamber depth, the estimation accuracy can be improved by using the information about the anterior eye for corneal angle estimation.

[0060] In the above description, the control unit 20 estimates the corneal angle or the anterior chamber depth based on the amount of iris splitting in the anterior eye observation image, but other methods may be used as long as the estimation is based on the anterior eye observation image. For example, the corneal angle or the anterior chamber depth may be estimated from the amount of iris defocus instead of the iris splitting state. The anterior eye observation optical system in the present embodiment is designed to be in focus when the distance between the device and the iris is suitable for fundus photography. That is, the closer the distance between the device and the iris, the greater the amount of defocus. Therefore, the control unit 20 may estimate the corneal angle or the anterior chamber depth using the amount of defocus obtained by analyzing the contrast of the iris in the anterior eye observation image. Alternatively, the control unit 20 may estimate the corneal angle or the anterior chamber depth based on the anterior eye images obtained from a plurality of image sensors arranged at different locations. By detecting the iris of the eye to be examined using a plurality of image sensors, the position of the iris in the Z direction can be calculated. This calculation method applies the principle of a stereo camera. The control unit 20 may estimate the corneal angle or the anterior chamber depth based on the calculated position of the iris in the Z direction. The plurality of image sensors are configured for anterior eye alignment, but since the images acquired for anterior eye alignment contain information on the Z direction position of the iris, they can also be applied to the estimation of the corneal angle and the anterior chamber depth.

[0061] Also, in the present embodiment, the control unit 20 adjusts the distance between the device and the cornea based on the presence or absence of corneal flare, but other methods may be used. For example, the control unit 20 may adjust the distance between the device and the cornea based on the corneal bright spot in the anterior eye observation image. The anterior eye observation image shows the corneal bright spot reflected by the light of the anterior eye observation light source. Since the corneal bright spot is a corneal reflection, the size and position of the corneal bright spot change according to the distance between the device and the cornea. For example, if two anterior eye observation light sources illuminate the anterior eye from the left and right, two corneal bright spots are observed in the anterior eye observation image. If the distance between these two corneal bright spots is large, it means that the reflection occurs on the outer side of the cornea, so it can be determined that the distance between the device and the cornea is close. Therefore, the control unit 20 may adjust the distance between the device and the cornea based on the size and position of the corneal bright spot.

[0062] Further, in the present embodiment, the control unit 20 estimates the angle of the anterior chamber angle or the anterior chamber depth based on the iris image after adjusting the distance between the device and the cornea. However, the angle of the anterior chamber angle or the anterior chamber depth may be estimated based on the cornea image after adjusting the distance between the device and the iris. For example, the control unit 20 may move the optical head to a position where the split amount of the iris in the anterior eye observation image reaches a predetermined amount, and estimate the angle of the anterior chamber angle or the anterior chamber depth based on the degree (such as area) of the corneal flare in the fundus observation image at that position.

[0063] Alternatively, the fundus camera device in the present embodiment may be configured to project a light beam of a light source different from the anterior eye observation light source onto the cornea and the iris. The configuration is, for example, a configuration in which slit light is projected from an angle different from the optical axis of the anterior eye observation optical system. The control unit 20 may estimate the angle of the anterior chamber angle or the anterior chamber depth using the images of the slit light reflected by the cornea and the iris included in the anterior eye observation image. This configuration is based on the same principle as a slit lamp microscope.

[0064] Note that the estimation of the angle of the anterior chamber angle or the anterior chamber depth may be based on image analysis using a rule base or may be based on estimation using machine learning. The anterior eye observation image varies depending on various imaging conditions (the distance between the device and the iris or the distance between the device and the cornea). Therefore, the control unit 20 may estimate the angle of the anterior chamber angle or the anterior chamber depth based on a learned model obtained by training the anterior eye observation images taken under various imaging conditions. In the training, a set of the anterior eye observation image and information regarding the angle of the anterior chamber angle or the anterior chamber depth of the eye to be examined corresponding to the anterior eye observation image may be used as teacher data for training. By such training, a learned model capable of obtaining information regarding the angle of the anterior chamber angle or the anterior chamber depth of the eye to be examined from the anterior eye observation image can be generated.

[0065] As described above, there are multiple methods for estimating the corneal angle or anterior chamber depth using the anterior eye observation image obtained by the two-dimensional sensor for anterior eye alignment. Whichever method is used, since the same configuration as that of a conventional fundus camera can be employed, it is possible to estimate the corneal angle or anterior chamber depth with an inexpensive configuration. Note that the present disclosure is applicable to ophthalmic devices other than fundus cameras (for example, tonometers) as well, for methods other than the method using corneal flare.

[0066] (Other Embodiments) Also, the disclosed technology can also be realized by executing the following processing. That is, the disclosed technology can be realized by supplying software (program) that realizes one or more functions of the various embodiments described above to a system or device via a network or a storage medium, and having a computer (or CPU, MPU, etc.) of the system or device read and execute the program. The computer may have one or more processors or circuits, and may include a plurality of separate computers or a network of separate processors or circuits for reading and executing computer-executable instructions. At this time, the processor or circuit may include a central processing unit (CPU), a microprocessing unit (MPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), or a field programmable gate array (FPGA). Also, the processor or circuit may include a digital signal processor (DSP), a data flow processor (DFP), or a neural processing unit (NPU).

[0067] The disclosure of the present embodiment includes the following configuration, method, and program.

[0068] (Configuration 1) Imaging means for imaging the eye to be examined, Drive means for driving to change the position of the imaging means so that the imaging means and the eye to be examined are at a predetermined distance, using the fundus image captured by the imaging means, Estimation means for estimating information regarding the corner of the eye to be examined using the anterior eye image captured by the imaging means at the predetermined distance; An ophthalmic apparatus comprising the same.

[0069] (Configuration 2) The ophthalmic apparatus according to Configuration 1, wherein the estimation means estimates information regarding the corner of the eye to be examined using at least one of the pupil or the iris included in the anterior eye image.

[0070] (Configuration 3) The ophthalmic apparatus according to any one of Configurations 1 or 2, wherein the estimation means estimates information regarding the corner of the eye to be examined using at least one of the split amount of the pupil or the split amount of the iris included in the anterior eye image.

[0071] (Configuration 4) The ophthalmic apparatus according to any one of Configurations 1 to 3, wherein the information regarding the corner is at least one of the result of comparison with the corner of a normal eye or the result of comparison with the anterior chamber depth of a normal eye.

[0072] (Configuration 5) The ophthalmic apparatus according to any one of Configurations 1 to 4, further comprising display control means for performing control to display the information regarding the corner estimated by the estimation means on a display unit.

[0073] (Configuration 6) The ophthalmic apparatus according to any one of Configurations 1 to 5, further comprising display control means for performing control to display the information regarding the corner on a display unit when the information regarding the corner estimated by the estimation means is information indicating that it is smaller than the information regarding the corner of a normal eye.

[0074] (Configuration 7) The ophthalmic apparatus further comprises illumination means for illuminating the eye to be examined with illumination light, The drive means performs drive to change the position of the imaging means so that the imaging means and the eye to be examined are at the predetermined distance, using the corneal reflection image in which the illumination light is reflected by the cornea of the eye to be examined included in the fundus image. The ophthalmic apparatus according to any one of Configurations 1 to 6.

[0075] (Configuration 8) The ophthalmic device according to Configuration 7, wherein the illumination light is infrared light.

[0076] (Configuration 9) Further comprising second illumination means for illuminating second illumination light having a wavelength different from the wavelength of the illumination light, The ophthalmic device according to any one of Configurations 7 to 8, wherein the imaging means captures the fundus image illuminated by the second illumination means at a second distance different from the predetermined distance.

[0077] (Configuration 10) The ophthalmic device according to Configuration 9, wherein the second illumination light is visible light.

[0078] (Configuration 11) The ophthalmic device according to any one of Configurations 1 to 10, wherein the estimation means estimates information regarding the corner of the eye to be examined using a learned model learned using a plurality of anterior eye images with different imaging conditions and information regarding the corner corresponding to the plurality of anterior eye images.

[0079] (Configuration 12) The ophthalmic device according to Configuration 11, wherein the imaging condition is at least one of the distance between the cornea of the eye to be examined and the imaging means or the distance between the iris of the eye to be examined and the imaging means.

[0080] (Configuration 13) Further having acquisition means for acquiring information regarding the anterior segment of the eye to be examined, The ophthalmic device according to any one of Configurations 1 to 12, wherein the driving means performs driving to change the position of the imaging means so that the imaging means and the eye to be examined are at the predetermined distance using the fundus image and the information regarding the anterior segment of the eye.

[0081] (Configuration 14) The ophthalmic device according to Configuration 13, wherein the information regarding the anterior segment of the eye to be examined includes at least one of information regarding the cornea of the eye to be examined or information regarding the presence or absence of an intraocular lens.

[0082] (Configuration 15) The ophthalmic device according to Configuration 14, wherein the information regarding the cornea includes at least one of information on whether the eye to be examined has keratoconus or information on whether refractive correction surgery has been performed.

[0083] (Configuration 16) An ophthalmic device including: imaging means for imaging an eye to be examined; drive means for driving to change the position of the imaging means so that a predetermined distance is obtained between the imaging means and the eye to be examined using a fundus image captured by the imaging means; and output means for outputting an anterior eye image captured by the imaging means at the predetermined distance. An information processing device including estimation means for estimating information regarding a corner of the eye to be examined using the anterior eye image output by the output means. An ophthalmic system having the above.

[0084] (Method 1) An imaging step of imaging an eye to be examined; A drive step of driving to change the position of the imaging means so that a predetermined distance is obtained between the imaging means for imaging the eye to be examined and the eye to be examined using the fundus image captured in the imaging step; An estimation step of estimating information regarding a corner of the eye to be examined using the anterior eye image captured by the imaging means at the predetermined distance. A control method for an ophthalmic system having the above.

[0085] (Program 1) A program for causing a computer to execute the control method described in Method 1.

Explanation of Reference Numerals

[0086] 10 Imaging unit 20 Control unit 40 Display unit 50 Input unit 100 Optical head unit 150 Stage unit 190 Base unit 160 Face support unit

Claims

1. Imaging means for imaging an eye to be examined; Drive means for driving to change the position of the imaging means so that the imaging means and the eye to be examined are at a predetermined distance, using the fundus image captured by the imaging means; Estimation means for estimating information regarding the corner of the eye to be examined using the anterior eye image captured by the imaging means at the predetermined distance; An ophthalmic apparatus comprising the above.

2. The ophthalmic apparatus according to claim 1, wherein the estimation means estimates information regarding the corner of the eye to be examined using at least one of the pupil and the iris included in the anterior eye image.

3. The ophthalmic apparatus according to claim 1, wherein the estimation means estimates information regarding the corner of the eye to be examined using at least one of the split amount of the pupil and the split amount of the iris included in the anterior eye image.

4. The ophthalmic apparatus according to claim 1, wherein the information regarding the corner is at least one of the result of comparison with the corner of a normal eye and the result of comparison with the anterior chamber depth of a normal eye.

5. The ophthalmic apparatus according to claim 1, further comprising display control means for performing control to display the information regarding the corner estimated by the estimation means on a display unit.

6. The ophthalmic apparatus according to claim 1, further comprising display control means for performing control to display the information regarding the corner on a display unit when the information regarding the corner estimated by the estimation means indicates that it is smaller than the information regarding the corner of a normal eye.

7. Further comprising illumination means for illuminating the eye to be examined with illumination light, The ophthalmic apparatus according to claim 1, wherein the drive means drives to change the position of the imaging means so that the imaging means and the eye to be examined are at the predetermined distance, using the corneal reflection image in which the illumination light is reflected by the cornea of the eye to be examined, which is included in the fundus image.

8. The ophthalmic apparatus according to claim 7, wherein the illumination light is infrared light.

9. Further comprising second illumination means for illuminating second illumination light having a wavelength different from the wavelength of the illumination light, The ophthalmic apparatus according to claim 7, wherein the imaging means captures the fundus image illuminated by the second illumination means at a second distance different from the predetermined distance.

10. The ophthalmic apparatus according to claim 9, wherein the second illumination light is visible light.

11. The ophthalmic apparatus according to claim 1, wherein the estimation means estimates information regarding the corner of the eye to be examined by using a learned model learned using a plurality of anterior eye images with different imaging conditions and information regarding the corner corresponding to the plurality of anterior eye images.

12. The ophthalmic apparatus according to claim 11, wherein the imaging condition is at least one of the distance between the cornea of the eye to be examined and the imaging means or the distance between the iris of the eye to be examined and the imaging means.

13. The ophthalmic apparatus further comprises acquisition means for acquiring information regarding the anterior segment of the eye to be examined, The ophthalmic apparatus according to claim 1, wherein the driving means uses the fundus image and the information regarding the anterior segment of the eye to be examined to drive to change the position of the imaging means so that the imaging means and the eye to be examined are at the predetermined distance.

14. The ophthalmic apparatus according to claim 13, wherein the information regarding the anterior segment of the eye to be examined includes at least one of information regarding the cornea of the eye to be examined or information regarding the presence or absence of an intraocular lens.

15. The ophthalmic apparatus according to claim 14, wherein the information regarding the cornea includes at least one of information as to whether the eye to be examined has keratoconus or information as to whether refractive correction surgery has been performed.

16. An ophthalmic apparatus comprising: imaging means for imaging an eye to be examined; driving means for driving to change the position of the imaging means so that the imaging means and the eye to be examined are at a predetermined distance by using a fundus image taken by the imaging means; and output means for outputting an anterior eye image taken by the imaging means at the predetermined distance; An information processing apparatus comprising estimation means for estimating information regarding the corner of the eye to be examined by using the anterior eye image output by the output means; An ophthalmic system having the above.

17. An imaging step of imaging an eye to be examined; A driving step of driving to change the position of the imaging means so that the imaging means for imaging the eye to be examined and the eye to be examined are at a predetermined distance by using the fundus image taken in the imaging step; An estimation step of estimating information regarding the corner of the eye to be examined by using the anterior eye image taken by the imaging means at the predetermined distance; A control method for an ophthalmic system having the above.

18. A program for causing a computer to execute the control method according to claim 17.

Images