Ophthalmic device

Abstract

This invention provides an ophthalmic device. The ophthalmic device includes: an imaging unit for capturing images of a target area of ​​an eye being examined; and a processing unit. The processing unit is configured to perform image acquisition processing and synthesis processing, wherein the image acquisition processing acquires a first image of the target area captured by the imaging unit and a second image of the target area captured at a time different from the first image; and the synthesis processing synthesizes the first image and the second image to generate an image of the target area. Accordingly, measurement results of a specific area of ​​the eye being examined can be appropriately acquired.

Description

Technical Field

[0001] The technology disclosed in this specification relates to an ophthalmic device. Background Technology

[0002] Ophthalmic devices have been developed for measuring specific locations (e.g., the anterior chamber angle) within the eye being examined. For example, Patent Document 1 discloses an ophthalmic device for capturing a reflected image of the anterior chamber angle of the eye being examined. In the reflected image of Patent Document 1, the entire anterior chamber angle of the eye being examined is captured.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Publication No. 2019-42304 Summary of the Invention

[0006] In an ophthalmic device like Patent Document 1, a specific area of ​​the examined eye is photographed as a whole. Thus, to evaluate the condition of a specific area within the examined eye (e.g., the anterior chamber angle), it is necessary to observe that area covering a predetermined range or more. However, depending on the eyelid opening state of the examined eye, sometimes only a narrower range than the predetermined range can be photographed. Therefore, in an ophthalmic device like Patent Document 1, if the area photographed is narrower than the predetermined range, the image of the specific area is re-photographed until a range larger than the predetermined range is captured. Therefore, depending on the condition of the examined eye, sometimes multiple photographs are necessary, or sometimes even with multiple re-photographs, a range larger than the predetermined range cannot be captured.

[0007] This specification discloses a technique for appropriately obtaining measurement results from specific sites of the examined eye.

[0008] The first ophthalmic device disclosed in this specification includes: an imaging unit for imaging a target area (object region) of an eye being examined; and a processing unit. The processing unit is configured to perform image acquisition processing and synthesis processing, wherein the image acquisition processing acquires a first image of the target area captured by the imaging unit and a second image of the target area captured at a time different from the first image; and the synthesis processing synthesizes the first image and the second image to generate an image of the target area.

[0009] In the aforementioned ophthalmic device, a single image is generated by synthesizing a first image and a second image capturing the target area of ​​the examined eye. For example, the corresponding portion of the second image can supplement the portion of the target area not captured in the first image. Therefore, the number of times the desired image of the target area of ​​the examined eye needs to be captured can be reduced, thereby alleviating the burden on the patient.

[0010] Furthermore, the second ophthalmic device disclosed in this specification measures the object region of the examined eye. The second ophthalmic device includes: an imaging unit for capturing images of the object region of the examined eye; a processing unit; and a notification unit. The processing unit is configured to perform image acquisition processing and non-detection region determination processing, wherein, in the image acquisition processing, an image of the object region captured by the imaging unit is acquired; and in the non-detection region determination processing, non-detection regions in the image of the object region where the object region was not detected are determined. The notification unit informs the non-detection regions determined by the processing unit.

[0011] In the aforementioned ophthalmic apparatus, by informing the examiner of the non-detection areas within the captured image, the examiner can determine the location of these non-detection areas. Therefore, for example, the examiner can re-capture the entire subject area including the non-detection areas, thereby reducing the number of captures required to obtain the desired image of the subject's eye and thus alleviating the burden on the examinee. Attached Figure Description

[0012] Figure 1 This is a diagram illustrating the schematic structure of the optical system of the ophthalmic device involved in the embodiment.

[0013] Figure 2 This is a diagram showing the general structure of a scanning-calibration optical system.

[0014] Figure 3 This is a block diagram illustrating the control system of the ophthalmic device involved in the embodiment.

[0015] Figure 4 This is a flowchart illustrating an example of the process of acquiring an image of the scleral spur of the examined eye.

[0016] Figure 5 This is a diagram used to illustrate the radial scanning method.

[0017] Figure 6 This is a diagram used to illustrate the raster scanning method.

[0018] Figure 7 (a) is a schematic diagram of the anterior eye image and tomographic image taken with the eye fully open, and (b) is a schematic diagram showing the position of the detection area and the scleral protuberance superimposed on (a).

[0019] Figure 8 (a) is a schematic diagram of the anterior eye image and tomographic image taken above and below the eye being examined without full eyelid opening, and (b) is a schematic diagram showing the position of the detection area and non-detection area and the scleral protuberance superimposed on (a).

[0020] Figure 9 This is a schematic diagram of anterior eye images and tomographic images taken with the lower eyelid of the examined eye open.

[0021] Figure 10 This is a schematic diagram of an image obtained by synthesizing the corresponding region of the second image onto the non-detection region of the first image.

[0022] Figure 11 This is a schematic diagram of anterior eye images and tomographic images taken with the upper eyelid of the examined eye open. Detailed Implementation

[0023] The main features of the embodiments described below are listed first. Furthermore, the technical elements described below are independent technical elements, which exert their technical utility individually or in various combinations, and are not limited to the combinations described in the technical solution at the time of application.

[0024] (Feature 1) The ophthalmic device disclosed in this specification may also include a display unit that displays an image of the target area. The display unit may also display an image of the target area synthesized through a synthesis process. With this structure, the synthesized image of the target area can be visually grasped.

[0025] (Feature 2) In the ophthalmic device disclosed in this specification, the first image may also be an image taken when the first region is in an open-eye state. The second image may also be an image taken when a second region, different from the first region, is in an open-eye state. According to this structure, the open-eye state of the examined eye when the first image is taken (the first region is in an open-eye state) is different from the open-eye state of the examined eye when the second image is taken (the second region is in an open-eye state). Therefore, the area photographed within the object region is different in the first image and the second image. By synthesizing these images, it is possible to obtain an image covering a larger area of ​​the object region.

[0026] (Feature 3) In the ophthalmic device disclosed in this specification, during the synthesis process, the common positions of the first image and the second image can be aligned to synthesize the first image and the second image. According to this structure, by aligning the common positions of the first image and the second image, it is possible to suppress the offset that occurs when synthesizing the first image and the second image.

[0027] (Feature 4) In the ophthalmic device disclosed in this specification, the arithmetic unit may also be configured to perform a non-detection region determination process, which determines non-detection regions in the first image where no object region is detected. In the synthesis process, a portion of the second image corresponding to the non-detection region of the first image may be synthesized from the portion where the object region of the first image is detected. According to this structure, by synthesizing a portion corresponding to the non-detection region of the second image from the portion where the object region of the first image is detected, the portion in the first image where no object region is detected can be replaced by the corresponding portion of the second image. Accordingly, an image containing a larger range of object regions can be acquired.

[0028] (Feature 5) The ophthalmic device disclosed in this specification may also include a notification unit that informs the user of non-detection areas when an image captured by the imaging unit contains non-detection areas of the subject eye. With this configuration, when the imaging unit captures an image of the subject eye's subject eye, and the captured image contains non-detection areas, the user is informed of these non-detection areas. Therefore, the examiner can determine the location of the non-detection areas that need to be re-captured. Thus, for example, the examiner can re-capture the image in a manner that includes the non-detection areas, obtaining a more suitable image for the synthesized image.

[0029] (Feature 6) In the ophthalmic device disclosed in this specification, the notification unit may also be configured to: instruct the examiner to open the eyelid above the eye when the non-detection area is above the eye being examined; instruct the examiner to open the eyelid below the eye when the non-detection area is below the eye being examined; and instruct the examiner to open the eyelid above and below the eye when the non-detection area is both above and below the eye being examined. With this configuration, the examiner can be instructed to obtain a more suitable image according to the location of the non-detection area.

[0030] [Example]

[0031] The ophthalmic device 1 described below is an example. The ophthalmic device 1 uses optical coherence tomography (OCT) to capture tomographic images of the anterior eye part of the examined eye E. For example... Figure 1 As shown, the ophthalmic device 1 includes a light source 10, an interference optical system 14 that causes the reflected light reflected from the examined eye E to interfere with the reference light, and a K-clock generator 50 that generates a K-clock signal.

[0032] Light source 10 is a wavelength scanning type light source, and the wavelength of the emitted light changes at a predetermined period. When the wavelength of the light emitted from light source 10 changes, the reflection position of the reflected light that interferes with the reference light in the light reflected from various parts of the examined eye E in the depth direction, corresponding to the wavelength of the emitted light, changes in the depth direction of the examined eye E. Therefore, by changing the wavelength of the emitted light while measuring the interference light, the position of various parts inside the examined eye E (e.g., cornea, lens, etc.) can be determined.

[0033] The light output from the light source 10 is input to the fiber optic coupler 12 via an optical fiber. The light input to the fiber optic coupler 12 is split in the fiber optic coupler 12 and output to the fiber optic coupler 16 and the K-clock generator 50 via an optical fiber. The K-clock generator 50 will be described later.

[0034] The interference optical system 14 consists of a measuring optical system, a reference optical system, and a balance detector 40. The measuring optical system illuminates the interior of the eye E with light from the light source 10 and generates reflected light. The reference optical system generates reference light based on the light from the light source 10. The balance detector 40 detects the interference light obtained by combining the reflected light guided by the measuring optical system and the reference light guided by the reference optical system.

[0035] The measurement optical system comprises a fiber optic coupler 16, a circulator 18, and a scanning-calibration optical system 20. Light output from the light source 10 and input to the fiber optic coupler 16 via the fiber optic coupler 12 is split into measurement light and reference light in the fiber optic coupler 16 and output. The measurement light output from the fiber optic coupler 16 is input to the circulator 18 via an optical fiber. The measurement light input to the circulator 18 is output to the scanning-calibration optical system 20. The scanning-calibration optical system 20 illuminates the eye being examined, E, with the measurement light output from the circulator 18, and outputs the reflected light from the eye being examined, E, back to the circulator 18. The reflected light input to the circulator 18 is input to one input section of the fiber optic coupler 38. The scanning-calibration optical system 20 will be described in detail later.

[0036] The reference optical system comprises a fiber optic coupler 16, a circulator 22, and a reference unit 24. Reference light output from the fiber optic coupler 16 is input to the circulator 22 via an optical fiber. The reference light input to the circulator 22 is output to the reference unit 24. The reference unit 24 comprises collimating lenses 26 and 28 and a reference mirror 30. The reference light output to the reference unit 24 is reflected by the reference mirror 30 via the collimating lenses 26 and 28, and then output from the reference unit 24 again via the collimating lenses 26 and 28. The reference light output from the reference unit 24 is output to the circulator 22. The collimating lens 28 and the reference mirror 30 are configured to be driven by a second drive device 54 (reference...). Figure 3 The collimator 28 moves forward and backward relative to the collimating lens 26. The second drive device 54 moves the collimating lens 28 and the reference mirror 30, thereby changing the optical path of the reference optical system. This allows the optical path of the reference optical system to be adjusted to approximately match that of the measuring optical system. The reference light input to the circulator 22 is input to the other input section of the fiber coupler 38 via the polarization controller 36. The polarization controller 36 is a component that controls the polarization of the reference light input to the fiber coupler 38. The polarization controller 36 can be a known polarization controller used in ophthalmic devices such as paddle-type or inline-type devices; therefore, a detailed description of it is omitted.

[0037] Fiber optic coupler 38 combines the reflected light and reference light input from the examined eye E to generate interference light. Fiber optic coupler 38 branches the generated interference light into two beams with a 180-degree phase difference and inputs them into balanced detector 40. Balanced detector 40 performs differential amplification and noise reduction processing on the two interference beams input from fiber optic coupler 38, converting them into electrical signals (interference signals). Balanced detector 40 outputs the interference signals to the arithmetic unit 60.

[0038] Here, refer to Figure 2 The structure of the scanning-calibration optical system 20 will be described. The scanning-calibration optical system 20 includes a scanning optical system, a front-eye imaging system, a fixation target optical system, and a calibration optical system.

[0039] like Figure 2 As shown, the scanning optical system includes a collimating lens 102, a galvano scanner 104, a thermal mirror 106, and an objective lens 108. From the circulator 18 (see reference...) Figure 1 The measurement light output is directed to the current scanner 104 via the collimating lens 102. The current scanner 104 is configured to be driven by the first drive device 52 (see reference 52). Figure 3 The first drive unit 52 tilts the current scanner 104 to scan the position of the measurement light irradiating the eye E under examination. The measurement light emitted from the current scanner 104 is irradiated by the thermal mirror 106 and reflected at an angle of 90 degrees. The measurement light irradiated by the thermal mirror 106 is then irradiated by the objective lens 108 onto the eye E under examination. The reflected light from the eye E is then, in the opposite manner, input into the circulator 18 via the objective lens 108, the thermal mirror 106, the current scanner 104, and the collimating lens 102.

[0040] The anterior eye imaging system includes two illumination sources 110, an objective lens 108, a hot mirror 106, a cold mirror 112, an imaging lens 114, a CCD camera 116, and an optical control unit 118. The two illumination sources 110 illuminate the visible light region of the subject eye E from the front. Reflected light from the subject eye E passes through the objective lens 108, hot mirror 106, cold mirror 112, and imaging lens 114 and is input to the CCD camera 116. Based on this, a frontal image of the subject eye E is captured. The captured image data is processed by the optical control unit 118 and displayed on a touchscreen 56.

[0041] The fixation target optical system comprises a fixation target light source 120, cold mirrors 122 and 124, a relay lens 126, a semi-reflecting mirror 128, a cold mirror 112, a hot mirror 106, and an objective lens 108. Light from the fixation target light source 120 passes through the cold mirrors 122 and 124, the relay lens 126, and the semi-reflecting mirror 128, and is reflected by the cold mirror 112. The light reflected by the cold mirror 112 passes through the hot mirror 106 and the objective lens 108 and is directed onto the examined eye E. By causing the subject to fixate on the light from the fixation target light source 120, the eyeball (i.e., the examined eye E) can be kept as still as possible.

[0042] The calibration optical system consists of an XY-direction position detection system and a Z-direction position detection system. The XY-direction position detection system is used to detect the position of the examined eye E (specifically, the corneal apex) in the XY direction (i.e., the vertical and horizontal positional offset relative to the ophthalmic device 1). The Z-direction position detection system is used to detect the position of the examined eye E in the anterior-posterior direction (Z-direction) of the corneal apex.

[0043] The XY position detection system includes an XY position detection light source 130, a cold mirror 124, a relay lens 126, a semi-reflecting mirror 128, a cold mirror 112, a hot mirror 106, an objective lens 108, an imaging lens 132, and a position sensor 134. The XY position detection light source 130 illuminates calibration light for position detection. The calibration light from the XY position detection light source 130 is reflected by the cold mirror 124, passes through the relay lens 126 and the semi-reflecting mirror 128, and is further reflected by the cold mirror 112. The light reflected by the cold mirror 112 passes through the hot mirror 106 and the objective lens 108 and is directed towards the anterior portion (cornea) of the examined eye E.

[0044] Since the corneal surface of the examined eye E is spherical, the calibration light is reflected from the corneal surface in such a way that it forms a bright spot image inside the corneal apex of the examined eye E. The reflected light from this corneal surface enters the objective lens 108, passes through the hot mirror 106, and is reflected by the cold mirror 112. The reflected light reflected by the cold mirror 112 is reflected by the semi-reflective mirror 128 and input to the position sensor 134 via the imaging lens 132. The position sensor 134 detects the position of the bright spot, and thereby detects the position of the corneal apex (i.e., the position in the X and Y directions).

[0045] The detection signal from the position sensor 134 is input to the processing unit 60 via the optical control unit 118. In this case, calibration between the position sensor 134 and the anterior eye imaging system is completed, and a predetermined (normal) image acquisition position (the position to be followed during tomographic image acquisition) of the corneal vertex is set. The normal image acquisition position of the corneal vertex is, for example, a point that coincides with the center position of the image captured by the CCD camera 116. Based on the detection by the position sensor 134, the processing unit 60 calculates the positional offset of the detected corneal vertex (bright spot) relative to the normal image acquisition position in the X and Y directions.

[0046] The Z-direction position detection system includes a Z-direction detection light source 140, an imaging lens 142, and a linear sensor 144. The Z-direction detection light source 140 illuminates the examined eye E from an oblique direction with light (slit light or point light). The obliquely reflected light from the cornea of ​​the examined eye E enters the linear sensor 144 via the imaging lens 142. The position of the reflected light entering the linear sensor 144 varies depending on the position of the examined eye E relative to the ophthalmic device 1 in the anterior-posterior direction (Z-direction). Therefore, the position of the examined eye E relative to the ophthalmic device 1 in the Z-direction is detected by detecting the position of the reflected light. The detection signal from the linear sensor 144 is input to the processing unit 60.

[0047] K-clock generator 50 (reference) Figure 1 In order to sample the interference signal at equal intervals (frequency intervals equal to the frequency of light), a sampling clock (K-clock) signal is optically generated based on the light from the light source 10. Then, the generated K-clock signal is output to the processing unit 60. Accordingly, the processing unit 60 samples the interference signal based on the K-clock signal to suppress distortion of the interference signal and prevent resolution degradation. Furthermore, in this embodiment, the interference signal obtained by sampling the K-clock signal at predetermined times is input to the processing unit 60, but this structure is not limited to this. For example, the processing unit 60 may perform scaling processing on the data sampled at certain time intervals, representing a function of frequency relative to a predetermined scan time or a simultaneously acquired scan profile.

[0048] Next, the structure of the control system of the ophthalmic device 1 in this embodiment will be described. For example... Figure 3As shown, the ophthalmic device 1 is controlled by a computing unit 60. The computing unit 60 is a microcomputer (microprocessor) composed of a CPU, ROM, RAM, etc. Connected to the computing unit 60 are a light source 10, a first driving device 52, a second driving device 54, an illumination light source 110, a fixation target light source 120, an XY position detection light source 130, a Z position detection light source 140, an optical control unit 118, a linear sensor 144, a balance detector 40, a K-clock generator 50, and a touch screen 56.

[0049] The arithmetic unit 60 controls the on / off state of the light source 10 and drives the current scanner 104 and the reference unit 24 by controlling the first drive unit 52 and the second drive unit 54. Additionally, an interference signal corresponding to the intensity of the interference light detected by the balance detector 40 is input to the arithmetic unit 60, and a K-clock signal generated by the K-clock generator 50 is also input. The arithmetic unit 60 samples the interference signal from the balance detector 40 based on the K-clock signal. Then, the arithmetic unit 60 performs a Fourier transform on the sampled interference signal to determine the positions of various parts of the examined eye E (e.g., cornea, anterior chamber, lens, etc.). The data input to the arithmetic unit 60 and the calculation results are stored in a memory (not shown).

[0050] Additionally, the computing unit 60 controls the on / off switching of the illumination source 110, the fixation target source 120, and the XY position detection source 130. The computing unit 60 inputs a frontal image of the examined eye E captured by the CCD camera 116 and processed by the optical control unit 118, and inputs the position of the corneal apex (bright spot) detected by the position sensor 134 via the optical control unit 118. The computing unit 60 calculates the offset of the corneal apex (bright spot) in the XY direction based on the input frontal image of the examined eye E and the position of the corneal apex (bright spot). The computing unit 60 inputs the detection signal from the linear sensor 144 and calculates the offset of the examined eye E relative to the ophthalmic device 1 in the Z direction. The arithmetic unit 60 controls the main body drive unit (not shown) to move the main body of the ophthalmic device 1 relative to the holding stage (not shown) by means of the positional offset of the corneal vertex (bright spot) in the X and Y directions detected by the XY direction position detection system and the positional offset of the examined eye E in the Z direction detected by the Z direction position detection system, so that all these positional offsets are reduced to 0.

[0051] Furthermore, the computing device 60 controls the touchscreen 56. The touchscreen 56 is a display device that provides the examiner with various information related to the measurement or analysis results of the examined eye E, and is a user interface that receives instructions or information from the examiner. For example, the touchscreen 56 can display anterior eye images, tomographic images, analysis results, and instructions to the examiner regarding the non-detection area 72 (details will be described later) of the examined eye E generated by the computing device 60. Additionally, the touchscreen 56 can input various settings of the ophthalmic device 1. While the ophthalmic device 1 of this embodiment includes a touchscreen 56, it is not limited to this structure. Any structure capable of displaying and inputting the aforementioned information is acceptable, and it may also include a monitor and input devices (e.g., a mouse and keyboard).

[0052] Reference Figures 4 to 11 The processing of acquiring images of the scleral spurs SS of the examined eye E will be explained. For example, when using tomographic images to evaluate the state of the angle recess, it is necessary to capture the tomographic images in a manner that includes the angle recess. However, when the examined eye E is not fully open, sometimes the upper or lower angle recess of the examined eye E is obscured by the eyelid and cannot be captured. In the ophthalmic apparatus 1 of this embodiment, an image of the angle recess of the examined eye E included in the circumferential whole will be acquired. Hereinafter, when the scleral spurs SS located in the anterior chamber angle are included in the image, it is determined that the angle recess is included in the image. Therefore, the processing of acquiring images of the scleral spurs SS of the examined eye E included in the circumferential whole will be explained.

[0053] like Figure 4 As shown, firstly, the processing unit 60 acquires a tomographic image of the anterior segment of the examined eye E (S12). The process of acquiring the tomographic image of the anterior segment of the examined eye E is performed according to the following steps. First, when the examiner inputs an instruction to start the examination via the touchscreen 56, the processing unit 60 calibrates the examined eye E and the ophthalmic device 1. The calibration is performed based on the offsets in the XY and Z directions detected by the calibration optics system. Specifically, the processing unit 60 moves the main body of the ophthalmic device 1 relative to the holding stage (not shown) in such a way that the positional offsets of the corneal apex (bright spot) in the X and Y directions detected by the XY direction position detection system and the positional offset of the examined eye E in the Z direction detected by the Z direction position detection system become 0, respectively.

[0054] When calibration is complete, the computing device 60 captures a tomographic image of the anterior eye region of the examined eye E. In this embodiment, the measurement of the anterior eye region of the examined eye E in step S12 is performed by radial scanning. Accordingly, a tomographic image of the anterior eye region is acquired covering the entire area. That is, as... Figure 5As shown, the B-scan direction is set to the radial direction emanating from the corneal apex of the examined eye E, and the C-scan direction is set to the circumferential direction for acquiring tomographic images. In this embodiment, tomographic images in 128 directions (specifically, 128 equally spaced directions along the circumference) are captured radially. The processing unit 60 stores the acquired (captured) tomographic image data in its memory. Furthermore, the method for capturing tomographic images of the anterior eye is not limited to a radial scanning method. It is sufficient to capture tomographic images of the anterior eye that covers the entire area; for example, a raster scanning method can also be used. That is, as... Figure 6 As shown, the scanning direction of B can also be set to the horizontal direction relative to the examined eye E, and the scanning direction of C can be set to the vertical direction to acquire tomographic images.

[0055] When a tomographic image of the anterior portion of the examined eye E is acquired in step S12, the processing unit 60 detects the scleral ridges SS in each tomographic image (S14). The scleral ridges SS in each tomographic image can be detected using known methods, therefore, the method is not particularly limited. For example, the scleral ridges SS in each tomographic image can be detected by the examiner inputting data into a two-dimensional tomographic image displayed on the touchscreen 56, or by the processing unit 60 executing a known image processing procedure (e.g., a procedure for detecting the posterior surface of the cornea and the anterior surface of the iris and determining their boundary point, etc.). Figure 7 As shown in (a), if the examined eye E is fully open during imaging, the scleral spur (SS) is detected at two locations in each of all tomographic images. In this case, the scleral spur (SS) is detected at two locations in each of all tomographic images. On the other hand, as... Figure 8 As shown in (a), if the examined eye E is not fully open during imaging, the scleral spurs SS above and below the examined eye E (or either of the scleral spurs SS above and below the examined eye E) may sometimes not be captured. In this case, the scleral spurs SS are not detected in multiple tomographic images that include the upper and lower portions of the examined eye E where the eyelids are not open (or either of the upper and lower portions).

[0056] Next, the processing unit 60 overlays the region 70 where the scleral protuberance SS is detected and the region 72 where the scleral protuberance SS is not detected onto the anterior eye image of the examined eye E and displays them on the touch screen 56 (S16). Specifically, the processing unit 60 overlays the circumferential region 70 where the scleral protuberance SS is detected (hereinafter referred to as "detection region 70") and the circumferential region 72 where the scleral protuberance SS is not detected (hereinafter referred to as "non-detection region 72") onto the anterior eye image for display.

[0057] like Figure 7As shown in (b), when scleral spurs (SS) are detected in all tomographic images in step S14, the detection area 70 is displayed with its entire circumference covered, and the non-detection area 72 is not displayed. At this time, the detection area 70 can be displayed by connecting line segments to the scleral spurs (SS) detected in adjacent tomographic images, or it can be displayed as a reference circle calculated based on the position of the detected scleral spurs (SS). Furthermore, the method for calculating the reference circle described above is, for example, the same as the known calculation method disclosed in Japanese Patent Publication No. 6367534, therefore, a detailed description is omitted. Hereinafter, this method for calculating the reference circle is sometimes referred to as "SS entire circumference fitting".

[0058] On the other hand, such as Figure 8 As shown in (b), when a tomographic image in step S14 contains an image in which no scleral spur SS is detected, only a portion of the circumferential direction corresponding to the location where the scleral spur SS is detected is displayed as the detection region 70, and the remaining portion of the circumferential direction corresponding to the location where the scleral spur SS is not detected is displayed as the non-detection region 72. The detection region 70 and the non-detection region 72 can be determined, for example, using SS full-circumference fitting. That is, the computing device 60 calculates a reference circle using the locations of the multiple detected scleral spur SS through SS full-circumference fitting, displays the range within the reference circle corresponding to the location where the scleral spur SS is detected as the detection region 70, and displays the range corresponding to the location where the scleral spur SS is not detected as the non-detection region 72. For example, as... Figure 8 As shown in (b), when the eyelids are not fully open above and below the examined eye E, the detection area 70 includes the left and right sides excluding the upper and lower areas, while the non-detection area 72 includes the upper and lower areas. Furthermore, in this embodiment, the detection area 70 is shown with a solid line, and the non-detection area 72 is shown with a dashed line. By displaying the detection area 70 and the non-detection area 72 in different forms, the examiner can easily distinguish between them.

[0059] Additionally, the touchscreen 56 displays an anterior eye image (specifically, an anterior eye image where the detection area 70 of the scleral spur SS overlaps with the non-detection area 72), and displays an image including the corneal apex, and aligned with the Y-axis and Z-axis (see reference). Figure 1 and Figure 2 A tomographic image of a parallel cross-section. The processing unit 60 overlays the line segment 74 representing the location of the scleral protuberance SS with the tomographic image displayed on the touch screen 56. Specifically, as Figure 7As shown in (b), when the detection area 70 is above and below the examined eye E, line segment 74 is displayed in the tomographic image at a position corresponding to the detection area 70 displayed in the anterior eye image. Therefore, in the tomographic image, the scleral spur SS is located on line segment 74. On the other hand, as Figure 8 As shown in (b), when there are non-detection areas 72 above and below the examined eye E (or, when either the area above or below the examined eye E is a non-detection area 72), line segment 74 is displayed at a position corresponding to the position of the non-detection area 72 in the pre-display eye image (i.e., the position on the reference circle). Therefore, the portion of the examined eye E not captured in the tomographic image is displayed as line segment 74.

[0060] Next, the processing unit 60 determines whether the anterior eye image displayed in step S16 contains a non-detection region 72 (S18). When the anterior eye image does not contain a non-detection region 72 (no in step S18), it can be determined that a tomographic image covering the entire circumference of the scleral protuberance SS has been acquired (see reference). Figure 7 (b)). Therefore, the processing of acquiring images of the scleral spurs SS of the examined eye E ends.

[0061] On the other hand, when the anterior eye image contains a non-detection region 72 (yes in step S18), it can be determined that there is a portion of the tomographic image where the scleral protuberance SS is not captured circumferentially. In this case, such as Figure 8 As shown in (b), the computing device 60 causes the touchscreen 56 to display a mark 76 indicating the non-detection area 72 (S20). For example, in Figure 8 In (b) of the diagram, there are non-detection areas 72 above and below the examined eye E. Therefore, markings 76 indicating the upper and lower non-detection areas 72 are displayed. This allows the examiner to be informed which area of ​​the examined eye E was not captured, thus prompting them to re-capture the non-detection areas 72. Therefore, the examiner can accurately identify the areas of the examined eye E that were not captured, thereby reducing the number of times the examined eye E needs to be re-captured. The examiner re-captures the anterior tomographic image of the examined eye E by capturing the non-detection areas 72, following the indicated markings 76. For example, if marking 76 indicating the upper part of the examined eye E is displayed, the examiner opens the upper eyelid of the examined eye E to capture the image. If markings 76 indicating the upper part and 76 indicating the lower part of the examined eye E are displayed, the examiner opens the upper and lower eyelids of the examined eye E to capture the image, or opens the upper and lower eyelids of the examined eye E to capture the image.

[0062] In addition, in this embodiment, a mark 76 indicating the non-detection area 72 is displayed, but this structure is not limited to. For example, the non-detection area 72 may be displayed in a form that is easier to observe than the detection area 70, such as displaying the detection area 70 and the non-detection area 72 in different colors (e.g., displaying the detection area 70 in green and the non-detection area 72 in red) or simply making the non-detection area 72 flash, as long as the non-detection area 72 can be informed to the inspector. Alternatively, instead of displaying the mark 76 for indicating the non-detection area 72 (or, together with the display of the mark 76), the non-detection area 72 may be informed by voice such as "Please retake the top and bottom shots".

[0063] Next, the processing unit 60 determines whether an instruction to start the examination for acquiring tomographic images of the examined eye E has been input (S22). That is, the processing unit 60 determines whether an instruction to re-capture tomographic images of the examined eye E has been input by the examiner. If no instruction to start the examination has been input (no in step S22), the processing unit 60 waits until an instruction to start the examination is input. On the other hand, if an instruction to start the examination has been input (yes in step S22), the processing unit 60 acquires tomographic images of the anterior segment of the examined eye E (S24) and detects the scleral protrusions SS in each acquired tomographic image (S26). Furthermore, the processing of steps S24 and S26 is the same as that of steps S12 and S14 described above, therefore, detailed explanations are omitted.

[0064] Next, the processing unit 60 performs a matching (S28) between the image acquired in step S12 (hereinafter also referred to as the first captured image) and the image acquired in step S24 (hereinafter also referred to as the second captured image). The captured area of ​​the examined eye E differs between the first captured image and the second captured image. For example, in the first captured image, the central portion excluding the area above and below the examined eye E is captured; on the other hand, as... Figure 9 As shown, the second image captures the lower and central portions, excluding the area above the examined eye E. The processing unit 60 uses the common portion of the capture range of the first and second images to align their positions. Therefore, during the subsequent composite processing, offsets between the first and second images can be suppressed.

[0065] Furthermore, the matching method is not particularly limited, and known methods can be used. For example, the following method can be used for matching. First, the processing unit 60 generates two-dimensional tomographic images according to the scanning angle for the first and second captured images, respectively. Additionally, the generated two-dimensional tomographic images each include the corneal vertex. Next, the processing unit 60 performs pattern matching on the multiple two-dimensional tomographic images obtained from the first and second captured images, and finds the angle difference that minimizes the difference. Specifically, while aligning the corneal vertex positions of the first and second captured images, while changing the angle between the reference line (a straight line passing through the corneal vertex) of the first captured image and the reference line (a straight line passing through the corneal vertex) of the second captured image, the luminance difference between the luminance corresponding to the multiple two-dimensional tomographic images obtained from the first captured image and the multiple two-dimensional tomographic images obtained from the second captured image is calculated for each of the multiple two-dimensional tomographic images obtained from the first captured image, and the sum of these calculated luminance differences is obtained. When calculating the brightness difference, the calculation is performed by comparing the brightness information of the anterior corneal surface in two corresponding two-dimensional tomographic images. Then, the sum of the brightness differences is determined to be the minimum angular difference (the angle between the baseline of the first image and the baseline of the second image). These angular differences are then defined as the angular offset between the first and second images (the offset of the scan angles of the two images). Finally, the positions of the first and second images are aligned, taking into account the determined angular offset (scan angle offset).

[0066] Alternatively, SS full-circumference fitting can be used for matching. Specifically, the computing device 60 first calculates a reference circle using SS full-circumference fitting for both the first and second captured images. Next, for the first captured image, the computing device 60 calculates the difference between the detected scleral ridge SS position and the reference circle, and uses the angle that minimizes the sum of these differences as the offset angle of the first captured image. Similarly, for the second captured image, the computing device 60 calculates the difference between the detected scleral ridge SS position and the reference circle, and uses the angle that minimizes the sum of these differences as the offset angle of the second captured image. Then, the positions of the first and second captured images are aligned in the XY direction with the center of the reference circle aligned, and the positions are offset relative to the first captured image by an amount corresponding to the offset angle of the first captured image, and the positions are also offset relative to the second captured image by an amount corresponding to the offset angle of the second captured image, thus aligning the positions of the first and second captured images in the angular direction.

[0067] Alternatively, anterior eye images can be used for matching. Specifically, the processing unit 60 first determines the iris of the examined eye E based on the anterior eye image corresponding to the first captured image and the anterior eye image corresponding to the second captured image, respectively. Next, the processing unit 60 performs matching in a manner consistent with the determined iris pattern, aligning the first captured image with the second captured image. For example, feature textures of the determined iris of the examined eye E are extracted from the first captured image, and feature textures of the determined iris of the examined eye E are extracted from the second captured image. Then, the micro-motion angle and movement amount of the first and second captured images are determined in a manner consistent with the feature textures extracted from the first and second captured images, aligning the two captured images.

[0068] Alternatively, measurement data of the examined eye E (e.g., measurement parameters that characterize the examined eye E) can be used for matching. Measurement data can include, for example, angle opening distance (AOD), but the type of measurement data used is not particularly limited. For example, the processing unit 60 first acquires AOD data from the first image and AOD data from the second image. The two AOD data points are identical in the common portion of the image area. Therefore, the processing unit 60 offsets one (or both) of the two AOD data points by overlapping the identical portions. Accordingly, the positions of the first and second images are aligned.

[0069] Next, the processing unit 60 replaces the non-detection region 72 of the first captured image with the corresponding region of the second captured image, and combines the two captured images (S30). That is, the processing unit 60 extracts the region corresponding to the non-detection region 72 of the first captured image from the second captured image and combines it with the detection region 70 of the first captured image. For example, as... Figure 8As shown in (b), the non-detection area 72 of the first image capture is located above and below the examined eye E. In the second image capture, the lower eyelid of the examined eye E is opened, while the upper eyelid is not. That is, the second image captures the scleral spur SS below the examined eye E, but not the upper eyelid SS. In this case, the processing unit 60 extracts from the second image both the area corresponding to the upper non-detection area 72 of the first image and the area corresponding to the lower non-detection area 72 of the first image, and combines them with the detection area 70 of the first image. Thus, together with the left and right scleral spurs SS of the examined eye E, an image is generated where the lower scleral spur SS of the examined eye E is captured (i.e., an image where only the upper scleral spur SS of the examined eye E is not captured).

[0070] Alternatively, the processing unit 60 may also extract only the portion detected in the second captured image and combine it with the first captured image. Specifically, the processing unit 60 first determines the detection region 70 and the non-detection region 72 in the second captured image. Then, the processing unit 60 extracts only the region in the detection region 70 of the second captured image that corresponds to the non-detection region 72 of the first captured image and combines it with the first captured image. That is, in the above example, the processing unit 60 extracts only the region from the second captured image that corresponds to the non-detection region 72 below the first captured image. Then, the processing unit 60 combines the extracted region of the second captured image (i.e., the region corresponding to the non-detection region 72 below the first captured image) on the detection region 70 and the non-detection region 72 above the first captured image.

[0071] Next, the processing unit 60 causes the touchscreen 56 to display the composite image generated in step S30, and displays the detection area 70 and the non-detection area 72 of the composite image overlaid on the composite image (S32). Then, the processing unit 60 determines whether the composite image generated in step S30 contains the non-detection area 72 (S34). If the composite image contains the non-detection area 72 (yes in step S34), the process returns to step S20 and repeats the processing of steps S20 to S34. On the other hand, if the composite image does not contain the non-detection area 72 (no in step S34), the process of acquiring the image of the scleral spur SS of the examined eye E ends.

[0072] For example, such as Figure 8 As shown in (b), the non-detection area 72 of the first image is located above and below the tested eye E, as shown in... Figure 9As shown, during the second image capture, if the lower eyelid of the examined eye E is opened but the upper eyelid is not, the composite image generated in step S30 will include the non-detection area 72 above the examined eye E. In this case, return to step S20, as... Figure 10 As shown, the processing unit 60 causes the touchscreen 56 to display a mark 76 indicating the non-detection area 72 above the examined eye E. Based on this, the examiner can know that the scleral protuberance SS above the examined eye E was not captured. Then, the examiner re-captures the examined eye E with the eyelid open above it, as instructed. Thus, as... Figure 11 As shown, the scleral protuberance SS above the examined eye E is photographed. Afterwards, the processing unit 60 executes steps S22 to S34, extracting a region corresponding to the non-detection area 72 above the examined eye E from the third photographed image, and synthesizing the extracted region from the third photographed image onto the composite image generated in the previous step S30. Thus, a... Figure 7 (a) shows an image of the scleral spur SS covering the entire circumference. Thus, even if an image of the scleral spur SS covering the entire circumference cannot be obtained in a single shot, an image of the desired range can be generated by synthesizing multiple images.

[0073] When using the ophthalmic device 1 of this embodiment, an image covering the entire circumference of the scleral spur SS can be generated by synthesizing multiple captured images. Therefore, it is unnecessary to take multiple images of the examined eye E until the desired image is obtained, thereby reducing the number of images required to acquire the desired image. Furthermore, since the non-detection area 72 is informed to the examiner, the examiner can appropriately determine the area that should be photographed again. Therefore, the number of images required to acquire the desired image can be reduced. Because the number of images can be reduced in this way, the burden on the patient can be reduced.

[0074] In this embodiment, an image is acquired (generated) that encompasses the entire circumferential region of the scleral spur SS, but this is not limited to this structure. The object of the image is not limited to the scleral spur SS; it can be any part or region within the examined eye E. For example, the object can be the anterior chamber angle containing the scleral spur SS, or it can be the anterior ocular region containing the cornea. Furthermore, the object can also include regions of tissue in the examined eye other than the anterior ocular region. Additionally, the synthesized image may not be generated entirely in a manner that includes the object, such as the scleral spur SS; if it includes a desired range, it may not include the entire object. For example, the synthesized image may not be generated entirely in a circumferential manner (i.e., 360 degrees) but rather in a manner that includes a desired range in the circumferential direction (e.g., 270 degrees or more).

[0075] The following points should be noted in relation to the ophthalmic device 1 described in the embodiments. The interference optics system 14 and the K-clock generator 50 of the embodiments are examples of an "image capturing unit", the touch screen 56 is an example of a "display unit" and an "information unit", and the arithmetic unit 60 is an example of an "arithmetic unit".

[0076] The above details specific examples of the technology disclosed in this specification, but these are merely examples and do not limit the scope of this technical solution. The technology described in the technical solution includes various modifications and alterations to the specific examples exemplified above. Furthermore, the technical elements described in this specification or the accompanying drawings, individually or in various combinations, contribute to the technical applicability and are not limited to the combinations described in the technical solution at the time of application.

Claims

1. An ophthalmic device, characterized in that, It includes: an imaging unit for photographing the subject area of ​​the eye being examined; and a processing unit. The arithmetic unit is configured to perform image acquisition processing and image synthesis processing, wherein... In the image acquisition process, a first image of the object region captured by the imaging unit and a second image of the object region captured at a time different from the first image are acquired. In the compositing process, the first image and the second image are combined to generate an image of the object region. The first image is an image taken when the first region is in an open-eye state, wherein the first region includes a portion of a defined area of ​​the object part. The second image is an image taken when the second region, different from the first region, is in an open-eye state, wherein the second region includes parts other than a portion of the defined range. The computation unit is configured to also perform a non-detection region determination process, which determines non-detection regions in the first image where the object portion was not detected. In the synthesis process, the portion of the first image in which the object region is detected is synthesized into the portion of the second image that corresponds to the non-detected region of the first image.

2. The ophthalmic device according to claim 1, characterized in that, It also includes a display unit for displaying an image of the object portion. The display unit displays an image of the object region synthesized through the synthesis process.

3. The ophthalmic device according to claim 1, characterized in that, In the compositing process, the common positions of the first image and the second image are aligned to compose the first image and the second image.

4. The ophthalmic device according to claim 1, characterized in that, It also has a notification unit that informs the non-detection area when the image captured by the imaging unit contains a non-detection area where the object part was not detected.

5. The ophthalmic device according to claim 4, characterized in that, The notification department is further configured as follows: When the non-detection area is above the eye being examined, an instruction is given to open the eyelid above the eye being examined; When the non-detection area is below the eye being examined, an instruction is given to open the lower eyelid of the eye being examined; Instructions are given to open the eyelids above and below the eye being examined when the non-detection area is above and below the eye being examined.

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