JP2022071191A - Ophthalmologic apparatus and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new technology to achieve accurate image acquisition and reduce an influence on measurement with simple control even when a movement of an eye to be examined, etc. occur during tracking control.

SOLUTION: An ophthalmologic apparatus includes: an optical system including an optical scanner; a movement mechanism; an image acquisition unit for acquiring an image of an eye to be examined; an abnormality detection unit for detecting an abnormality on the basis of a reference image and the image of the eye to be examined; an alignment control unit for executing positioning of the optical system when an abnormality is detected; a scan control unit for causing a first scan or a second scan to be re-executed from a starting position of the first scan being executed for the eye to be examined or the second scan executed before the first scan, after the positioning is completed; and a tracking control unit for controlling the movement mechanism on the basis of the reference image and the image of the eye to be examined when an abnormality is not detected. An image of the eye to be examined is re-acquired after the first scan or the second scan is re-executed, and an abnormality is detected by using the re-acquired image.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an ophthalmic apparatus and a method for controlling the same.

Ophthalmic devices for photographing the eye to be inspected include devices using optical coherence tomography (OCT), fundus cameras, scanning laser ophthalmoscopes (SLO), slit lamps, and the like. .. Among them, OCT that forms an image showing the surface morphology and the internal morphology of the target eye by using a light beam from a laser light source or the like is attracting attention. Since OCT does not have invasiveness to the human body like X-ray CT, it is expected to be applied especially in the medical field and the biology field. For example, in the field of ophthalmology, a device for forming an image of the anterior segment of the eye to be inspected and measuring the intraocular distance has been put into practical use.

In such an ophthalmic apparatus, tracking is an important technique for acquiring a high-definition image and measuring with high accuracy regardless of the eye movement of the eye to be inspected. Tracking is to move the device optical system according to the eye movement of the eye to be inspected. When tracking is performed, alignment and focusing are performed in advance. Tracking is a function of maintaining a suitable positional relationship in which alignment and focus are achieved by making the position of the optical system of the device follow the eye movement.

If the eye to be inspected moves or blinks during such tracking, it becomes difficult to continue the tracking control, and accurate image acquisition and measurement cannot be performed. For example, Patent Documents 1 to 3 disclose methods for reducing the influence on accurate image acquisition and measurement even when the eye to be inspected moves or blinks.

Patent Document 1 discloses a fundus observation device that obtains a position shift of the fundus during scanning and corrects the position of the acquired A-scan image based on the obtained position shift.

Further, Patent Document 2 discloses a fundus camera that detects the occurrence of blinking of a subject and sets the imaging timing after a predetermined time has elapsed from the detection timing of the occurrence of blinking.

Further, Patent Document 3 discloses an ophthalmic apparatus that predicts the blink occurrence cycle from the detection result of the blink occurrence of the subject and permits data collection of the eye to be inspected based on the predicted cycle.

Japanese Unexamined Patent Publication No. 2010-264225 Japanese Unexamined Patent Publication No. 2009-131591 Japanese Unexamined Patent Publication No. 2016-052386

However, the conventional method has problems that the processing load for reducing the influence on image acquisition and measurement becomes heavy and the control becomes complicated.

The present invention has been made in view of such circumstances, and an object of the present invention is to reduce the influence on accurate image acquisition and measurement by simple control even when the eye to be inspected moves during tracking control. It is to provide new technology to do so.

One embodiment of the embodiment comprises an optical system comprising an optical scanner, deflecting light from a light source by the optical scanner and projecting it onto an eye to be inspected, and receiving light based on the return light from the eye to be inspected, and the subject. Abnormality based on a moving mechanism that relatively moves between the eye examination and the optical system, an image acquisition unit that acquires an image of the eye to be inspected, and a reference image and an image of the eye to be inspected acquired by the image acquisition unit. An abnormality detection unit that detects an abnormality, an alignment control unit that executes alignment of the optical system with respect to the eye to be inspected by controlling the movement mechanism when an abnormality is detected by the abnormality detection unit, and the alignment control unit. After the alignment is completed, the light source is located at the start position of the first scan being executed for the eye to be inspected or the second scan executed before the first scan at the acquisition timing of the image of the eye to be inspected. A scan control unit that controls the optical scanner to re-execute the first scan or the second scan so as to project light from the light, and the reference image when an abnormality is not detected by the abnormality detection unit. The first scan or the second scan was re-executed, including a tracking control unit that controls the movement mechanism so that the optical system follows the movement of the eye to be inspected based on the image of the eye to be inspected. After that, the image acquisition unit reacquires the image of the eye to be inspected, and the abnormality detection unit detects the abnormality using the reacquired image.

Another embodiment of the embodiment comprises an optical system comprising an optical scanner, deflecting light from a light source by the optical scanner and projecting it onto an eye to be inspected, and receiving light based on the return light from the eye to be inspected, and the subject. It is a control method of an ophthalmic apparatus including a moving mechanism that relatively moves between an optometry and the optical system. The control method of the ophthalmologic apparatus includes an image acquisition step of acquiring an image of the eye to be inspected, an abnormality detection step of detecting an abnormality based on a reference image and an image of the eye to be inspected, and when the abnormality is detected. After the alignment control step of executing the alignment of the optical system with respect to the eye to be inspected by controlling the movement mechanism and the alignment in the alignment control step are completed, the eye to be inspected is at the acquisition timing of the image of the eye to be inspected. The optical scanner is controlled to project light from the light source to the start position of the first scan being executed or the second scan executed prior to the first scan, and the first scan or the first scan is performed. The scan control step to re-execute the second scan, and when the abnormality is not detected, the movement so as to make the optical system follow the movement of the eye to be inspected based on the reference image and the image of the eye to be inspected. The tracking control unit step for controlling the mechanism is included, and after the first scan or the second scan is re-executed, the image acquisition step re-acquires the image of the eye to be inspected, and the abnormality detection step re-executes the second scan. The abnormality is detected using the acquired image.

According to the present invention, even if the eye to be inspected moves during tracking control, it is possible to reduce the influence on accurate image acquisition and measurement by simple control.

It is a schematic diagram which shows an example of the structure of the optical system of the ophthalmologic apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the optical system of the ophthalmologic apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the processing system of the ophthalmologic apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the processing system of the ophthalmologic apparatus which concerns on embodiment. It is a flow chart of the operation example of the ophthalmologic apparatus which concerns on embodiment. It is a flow chart of the operation example of the ophthalmologic apparatus which concerns on embodiment.

An example of an ophthalmic apparatus according to the present invention and an embodiment of a control method thereof will be described in detail with reference to the drawings. In addition, the description contents of the document cited in this specification and arbitrary known techniques can be incorporated into the following embodiments.

The ophthalmic apparatus according to the embodiment includes an optical scanner, which deflects light from a light source by an optical scanner and projects it onto an eye to be inspected, and light based on the return light from the eye to be inspected (including a part of the return light). It is equipped with an optical system that receives light, and it is possible to acquire information about the eye to be inspected. Such optical systems include OCT optical systems and SLO optical systems. The OCT optical system divides the light from the OCT light source into the measurement light and the reference light, projects the measurement light onto the test eye via an optical scanner, and passes through the return light of the measurement light from the test eye and the reference light path. Receives interference light with reference light. The SLO optical system projects the SLO light from the SLO light source onto the eye to be inspected via an optical scanner, and receives the return light of the SLO light from the eye to be inspected.

Hereinafter, a case where the ophthalmic apparatus according to the embodiment images the eye to be inspected by performing OCT on the eye to be inspected will be described, but the embodiment is not limited to this. For example, the ophthalmic apparatus according to the embodiment may be capable of measuring the intraocular distance of a living eye such as the axial length by performing OCT on the eye to be inspected, or may be able to form an SLO image. good.

The ophthalmologic apparatus according to the embodiment is an ophthalmologic apparatus in which a Fourier domain OCT and a fundus camera are combined. This ophthalmic appliance has the ability to perform swept source OCT, but the embodiments are not limited to this. For example, the type of OCT is not limited to swept source OCT, and may be spectral domain OCT or the like. The swept source OCT divides the light from the wavelength sweep type (wavelength scanning type) light source into the measurement light and the reference light, and causes the return light of the measurement light that has passed through the object to be measured to interfere with the reference light to generate interference light. This is a method in which the interference light is detected by a balanced photodiode or the like, and the detection data collected in response to the wavelength sweep and the scan of the measurement light is subjected to Fourier transform or the like to form an image. Spectral domain OCT divides the light from the low coherence light source into the measurement light and the reference light, and causes the return light of the measurement light that has passed through the object to be measured to interfere with the reference light to generate interference light. This is a method in which the spectral distribution is detected by a spectroscope and the detected spectral distribution is subjected to Fourier transform or the like to form an image.

The ophthalmic apparatus according to the embodiment is provided with a scanning laser ophthalmoscope (SLO), a slit lamp microscope, an anterior ocular segment photographing camera, a surgical microscope, a photocoagulation apparatus, and the like, instead of the fundus camera. May be good. In this specification, the measurement by OCT is collectively referred to as "OCT measurement", the image acquired by OCT is collectively referred to as an OCT image, the optical path of measurement light is referred to as "measurement optical path", and the optical path of reference light is referred to as "reference". It may be written as "optical path".

[Constitution]
As shown in FIG. 1, the ophthalmic apparatus 1 according to the embodiment includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The fundus camera unit 2 has an optical system substantially similar to that of a conventional fundus camera. The OCT unit 100 is provided with an optical system for executing OCT. The arithmetic control unit 200 includes a processor that executes various arithmetic processes, control processes, and the like.

In the present specification, the "processor" is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (for example, a SPLD (Simple Device)), a programmable logic device (for example, a SPLD) It means a processing circuit including Programmable Logic Device), FPGA (Field Programgable Gate Array), and the like. The processor realizes the function according to the embodiment by reading and executing a program stored in a storage circuit or a storage device, for example.

[Fundus camera unit]
The fundus camera unit 2 is provided with an optical system for acquiring a two-dimensional image (fundus image) showing the surface morphology of the fundus Ef of the eye to be inspected E. The fundus image includes an observation image, a photographed image, and the like. The observation image is, for example, a monochrome moving image formed at a predetermined frame rate using near-infrared light. The captured image may be, for example, a color image obtained by flashing visible light, or a monochrome still image using near-infrared light or visible light as illumination light. The fundus camera unit 2 may be configured to be capable of acquiring images other than these, such as a fluorescein fluorescent image, an indocyanine green fluorescent image, and a spontaneous fluorescent image.

The fundus camera unit 2 is provided with a chin rest and a forehead pad for supporting the face of the subject. Further, the fundus camera unit 2 is provided with an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the fundus Ef with illumination light. The photographing optical system 30 guides the fundus reflected light of this illumination light to an image pickup device (CCD image sensor (sometimes simply referred to as CCD) 35, 38). Further, the photographing optical system 30 guides the measurement light from the OCT unit 100 to the eye to be inspected E, and guides the measurement light passing through the eye to be inspected E to the OCT unit 100.

The observation light source 11 of the illumination optical system 10 is composed of, for example, a halogen lamp or an LED (Light Emitting Diode). The light output from the observation light source 11 (observation illumination light) is reflected by the reflection mirror 12 having a curved reflecting surface, passes through the condenser lens 13, passes through the visible cut filter 14, and becomes near-infrared light. Become. Further, the observation illumination light is once focused in the vicinity of the photographing light source 15, reflected by the mirror 16, and passes through the relay lenses 17, 18, the diaphragm 19, and the relay lens 20. Then, the observation illumination light is reflected at the peripheral portion of the perforated mirror 21 (the region around the perforated portion), passes through the dichroic mirror 46, is refracted by the objective lens 22, and illuminates the fundus Ef.

The fundus reflected light of the observation illumination light is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central region of the perforated mirror 21, passes through the dichroic mirror 55, and focuses on photography. It is reflected by the mirror 32 via the lens 31. Further, the reflected light from the fundus of the eye passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light receiving surface of the CCD image sensor 35 by the condenser lens 34. The CCD image sensor 35 detects the fundus reflected light at a predetermined frame rate, for example. An image (observation image) based on the fundus reflected light detected by the CCD image sensor 35 is displayed on the display device 3. When the photographing optical system 30 is focused on the anterior eye portion, the reflected light of the observation illumination light from the anterior eye portion is detected by the CCD image sensor 35, and the observation image of the anterior eye portion based on the reflected light. Is displayed on the display device 3.

The photographing light source 15 is composed of, for example, a xenon lamp or an LED. The light output from the photographing light source 15 (photographing illumination light) is applied to the fundus Ef through the same path as the observation illumination light. The fundus reflected light of the photographing illumination light is guided to the dichroic mirror 33 through the same path as that of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is reflected by the condenser lens 37 of the CCD image sensor 38. An image is formed on the light receiving surface. An image (photographed image) based on the fundus reflected light detected by the CCD image sensor 38 is displayed on the display device 3. The display device 3 for displaying the observed image and the display device 3 for displaying the captured image may be the same or different. Further, when the eye E to be inspected is illuminated with infrared light and the same imaging is performed, an infrared captured image is displayed. It is also possible to use an LED as a shooting light source. When the photographing optical system 30 is focused on the anterior eye portion, the reflected light of the observation illumination light from the anterior eye portion is detected by the CCD image sensor 38, and the image of the anterior eye portion based on the reflected light ( The captured image) is displayed on the display device 3.

The LCD (Liquid Crystal Display) 39 displays a fixative and a visual acuity measurement target. The fixative is a fixative for fixing the eye E to be inspected, and is used at the time of fundus photography, OCT measurement, and the like.

A part of the light output from the LCD 39 is reflected by the half mirror 33A, reflected by the mirror 32, passes through the photographing focusing lens 31 and the dichroic mirror 55, and passes through the hole portion of the perforated mirror 21. The light that has passed through the hole of the perforated mirror 21 passes through the dichroic mirror 46, is refracted by the objective lens 22, and is irradiated to the fundus Ef. By changing the display position of the fixative on the screen of the LCD 39, the fixative position of the eye E to be inspected can be changed.

Further, the fundus camera unit 2 is provided with an alignment optical system 50 and a focus optical system 60, as in the conventional fundus camera. The alignment optical system 50 generates an optotype (alignment optotype) for aligning the device optical system with respect to the eye E to be inspected. The focus optical system 60 generates an optotype (split optotype) for focusing on the eye E to be inspected.

The light (alignment light) output from the LED 51 of the alignment optical system 50 is reflected by the dichroic mirror 55 via the diaphragms 52 and 53 and the relay lens 54, and passes through the hole portion of the perforated mirror 21. The light that has passed through the hole of the perforated mirror 21 passes through the dichroic mirror 46 and is irradiated to the cornea of the eye E to be inspected by the objective lens 22.

The corneal reflected light of the alignment light passes through the objective lens 22, the dichroic mirror 46, and the above-mentioned hole portion, and a part thereof passes through the dichroic mirror 55 and passes through the photographing focusing lens 31. The corneal reflected light that has passed through the photographing focusing lens 31 is reflected by the mirror 32, transmitted through the half mirror 33A, reflected by the dichroic mirror 33, and projected onto the light receiving surface of the CCD image sensor 35 by the condenser lens 34. The light-receiving image (alignment optotype) obtained by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The user performs the alignment by performing the same operation as the conventional fundus camera. Further, the arithmetic control unit 200 may analyze the position of the alignment optotype and move the optical system to perform alignment (auto alignment function).

The focus optical system 60 is movable along the optical path of the illumination optical system 10. The photographing focusing lens 31 is movable along the optical path of the photographing optical system 30 in conjunction with the movement of the focusing optical system 60. The reflection rod 67 of the focus optical system 60 is removable with respect to the illumination optical path.

When adjusting the focus, the reflecting surface of the reflecting rod 67 is obliquely provided on the illumination optical path. The light (focus light) output from the LED 61 of the focus optical system 60 passes through the relay lens 62, is separated into two light fluxes by the split viewing plate 63, and passes through the two-hole diaphragm 64. The light that has passed through the two-hole diaphragm 64 is reflected by the mirror 65, and is once imaged and reflected on the reflecting surface of the reflecting rod 67 by the condenser lens 66. The light reflected by the reflecting surface of the reflecting rod 67 passes through the relay lens 20, is reflected by the perforated mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is covered as a pair of split optotypes. The eye examination E is irradiated.

The pair of split target lights that have passed through the pupil of the eye E to be inspected reach the fundus Ef of the eye E to be inspected. The fundus reflected light of the pair of split target lights passes through the pupil and is detected by the CCD image sensor 35 through the same path as the fundus reflected light flux of the illumination light. The received light image (a pair of split optotype images) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The arithmetic control unit 200 analyzes the positions of the pair of split optotypes and moves the focus optical system 60 to perform focusing (autofocus function), as in the conventional case. By moving the photographing focusing lens 31 in conjunction with the movement of the focus optical system 60, the fundus image is formed on the image pickup surface of the CCD image sensor 35. Further, focusing may be performed manually (by operating the operation unit 240B described later) while visually recognizing the pair of split optotype images.

The reflection rod 67 is inserted at a position on the illumination optical path that is optically conjugate with the fundus Ef of the eye E to be inspected. The position of the reflecting surface of the reflecting rod 67 inserted in the optical path of the illumination optical system 10 is a position substantially coupled to the split visual reference plate 63. As described above, the focus target light is separated into two by the action of the two-hole diaphragm 64 and the like. When the fundus Ef and the reflecting surface of the reflecting rod 67 are not conjugate, the pair of split optotype images acquired by the CCD image sensor 35 are displayed on the display device 3, for example, by separating them into two in the left-right direction. .. When the fundus Ef and the reflecting surface of the reflecting rod 67 are substantially conjugated, the pair of split optotype images acquired by the CCD image sensor 35 are displayed on the display device 3 in the vertical direction, for example, in coincide with each other. When the focus optical system 60 is moved along the illumination optical path so that the fundus Ef and the split optotype 63 are always optically coupled, the photographing focusing lens 31 moves along the photographing optical axis in conjunction with this. Moving. When the fundus Ef and the split optotype 63 are not conjugate, the pair of split optotypes are separated into two, so that the pair of split optotypes coincide with each other in the vertical direction. The position of the photographing focusing lens 31 can be obtained by moving the lens 31. In this embodiment, the case where a pair of split optotypes is acquired has been described, but it may be three or more split optotypes.

The dichroic mirror 46 branches the optical path for OCT from the optical path for observation / photographing. The dichroic mirror 46 reflects light in the wavelength band used for OCT and transmits light for observation / photographing. The optical path for OCT is provided with a collimator lens unit 40, an optical path length changing unit 41, an optical scanner 42, an OCT focusing lens 43, a mirror 44, and a relay lens 45 in order from the OCT unit 100 side. Has been done.

The collimator lens unit 40 includes a collimator lens. The collimator lens unit 40 is optically connected to the OCT unit 100 by an optical fiber. The collimator lens of the collimator lens unit 40 is arranged at a position facing the emission end of the optical fiber. The collimator lens unit 40 converts the measurement light LS (described later) emitted from the emission end of the optical fiber into a parallel light beam, and collects the return light of the measurement light from the eye E to be examined to the emission end.

The optical path length changing unit 41 is movable in the direction of the arrow shown in FIG. 1, and changes the optical path length of the optical path for OCT. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye E to be inspected, adjusting the interference state, and the like. The optical path length changing unit 41 includes, for example, a corner cube and a mechanism for moving the corner cube.

The optical scanner 42 is arranged, for example, at a position optically conjugate with the pupil of the eye E to be inspected. The optical scanner 42 changes the traveling direction of the light (measurement light LS) passing through the optical path for OCT. Thereby, the eye E to be inspected can be scanned by the measurement light LS. The optical scanner 42 includes, for example, a galvano mirror that scans the measurement light LS in the x direction, a galvano mirror that scans the measurement light LS in the y direction, and a mechanism that independently drives them. Thereby, the measurement light LS can be scanned in any direction on the xy plane.

The OCT focusing lens 43 can move along the optical path (optical axis of the interference optical system) of the measurement light LS.

The ophthalmic appliance 1 is provided with a front lens 23 that can be arranged between the eye to be inspected E and the objective lens 22. The front lens 23 can be manually placed between the eye E to be inspected and the objective lens 22. The front lens 23 may be automatically arranged between the eye E to be inspected and the objective lens 22 under the control of the control unit 210 described later. When the anterior lens 23 is retracted from between the eye to be inspected E and the objective lens 22, the focal position of the measurement light is arranged at or near the fundus Ef of the eye to be inspected E, and OCT measurement is performed on the fundus Ef. be able to. When the anterior lens 23 is arranged between the eye to be inspected E and the objective lens 22, the focal position of the measurement light is moved from the fundus Ef and arranged in or near the anterior eye portion, with respect to the anterior eye portion. OCT measurement can be performed.

[OCT unit]
An example of the configuration of the OCT unit 100 is shown in FIG. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the eye E to be inspected. This optical system divides the light from the wavelength sweep type (wavelength scanning type) light source into the measurement light and the reference light, and causes the return light of the measurement light from the subject E to interfere with the reference light passing through the reference optical path. This is an interference optical system that generates interference light and detects this interference light. The detection result (detection signal) of the interference light by the interference optical system is an interference signal showing the spectrum of the interference light, and is sent to the arithmetic control unit 200.

The light source unit 101 is configured to include a wavelength sweep type (wavelength scanning type) light source capable of sweeping (scanning) the wavelength of emitted light, similar to a general swept source type ophthalmic apparatus. The wavelength sweep type light source is configured to include a laser light source including a resonator. The light source unit 101 changes the output wavelength with time in a near-infrared wavelength band that cannot be visually recognized by the human eye.

The light L0 output from the light source unit 101 is guided to the polarization controller 103 by the optical fiber 102, and its polarization state is adjusted. The polarization controller 103 adjusts the polarization state of the light L0 guided in the optical fiber 102 by, for example, applying stress from the outside to the looped optical fiber 102.

The light L0 whose polarization state is adjusted by the polarization controller 103 is guided by the optical fiber 104 to the fiber coupler 105 and divided into the measurement light LS and the reference light LR.

The reference light LR is guided to the collimator 111 by the optical fiber 110 and becomes a parallel light flux. The reference light LR that has become a parallel luminous flux is guided to the optical path length changing unit 114. The optical path length changing unit 114 is movable in the direction of the arrow shown in FIG. 2, and changes the optical path length of the reference light LR. This movement changes the length of the optical path of the reference light LR. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye E to be inspected, adjusting the interference state, and the like. The optical path length changing unit 114 includes, for example, a corner cube and a moving mechanism for moving the corner cube. In this case, the corner cube of the optical path length changing portion 114 turns back the traveling direction of the reference light LR, which is made into a parallel luminous flux by the collimator 111, in the opposite direction. The optical path of the reference light LR incident on the corner cube and the optical path of the reference light LR emitted from the corner cube are parallel.

In the configurations shown in FIGS. 1 and 2, the optical path length changing unit 41 for changing the length of the optical path (measurement optical path, measurement arm) of the measurement light LS and the optical path of the reference light LR (reference optical path, reference). Both of the optical path length changing portions 114 for changing the length of the arm) are provided. However, only one of the optical path length changing portions 41 and 114 may be provided. Further, it is also possible to change the difference between the reference optical path length and the measured optical path length by using an optical member other than these.

The reference light LR that has passed through the optical path length changing unit 114 is converted from a parallel light flux to a focused light flux by the collimator 116 and is incident on the optical fiber 117.

An optical path length correction member may be arranged at least one of the reference optical path between the collimator 111 and the optical path length changing unit 114 and the reference optical path between the collimator 116 and the optical path length changing unit 114. The optical path length correction member acts as a delay means for matching the optical path length (optical distance) of the reference light LR with the optical path length of the measured light LS.

The reference light LR incident on the optical fiber 117 is guided by the polarization controller 118 to adjust its polarization state. The polarization controller 118 has, for example, the same configuration as the polarization controller 103. The reference light LR whose polarization state is adjusted by the polarization controller 118 is guided to the attenuator 120 by the optical fiber 119, and the amount of light is adjusted under the control of the arithmetic control unit 200. The reference optical LR whose light amount is adjusted by the attenuator 120 is guided to the fiber coupler 122 by the optical fiber 121.

On the other hand, the measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and is converted into a parallel luminous flux by the collimator lens unit 40. The measured light LS converted into a parallel luminous flux is guided to the dichroic mirror 46 via the optical path length changing unit 41, the optical scanner 42, the OCT focusing lens 43, the mirror 44, and the relay lens 45. The measurement light LS guided to the dichroic mirror 46 is reflected by the dichroic mirror 46, refracted by the objective lens 22, and irradiated to the eye E to be inspected. The measurement light LS is scattered (including reflection) at various depth positions of the eye E to be inspected. The return light of the measurement light LS including such backscattered light travels in the same path as the outward path in the opposite direction, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

The fiber coupler 122 combines (interferes with) the measurement light LS incidented via the optical fiber 128 and the reference light LR incident via the optical fiber 121 to generate interference light. The fiber coupler 122 generates a pair of interference light LCs by branching the interference light between the measurement light LS and the reference light LR at a predetermined branching ratio (for example, 1: 1). The pair of interference light LCs emitted from the fiber coupler 122 are guided to the detector 125 by the optical fibers 123 and 124, respectively.

The detector 125 is, for example, a balanced photodiode (Balanced Photo Diode) that has a pair of photodetectors that detect each pair of interference light LCs and outputs the difference between the detection results. The detector 125 sends the detection result (interference signal) to the DAT (Data Acquisition System) 130. A clock KC is supplied to the DAQ 130 from the light source unit 101. The clock KC is generated in the light source unit 101 in synchronization with the output timing of each wavelength swept (scanned) within a predetermined wavelength range by the wavelength sweep type light source. The light source unit 101 optically delays one of the two branched lights obtained by branching the light L0 of each output wavelength, and then sets the clock KC based on the result of detecting these combined lights. Generate. The DAQ 130 samples the detection result of the detector 125 based on the clock KC. The DAQ 130 sends the detection result of the sampled detector 125 to the arithmetic control unit 200. The arithmetic control unit 200 obtains a reflection intensity profile in each A line by, for example, performing a Fourier transform or the like on the spectral distribution based on the detection result obtained by the detector 125 for each series of wavelength scans (for each A line). Form. Further, the arithmetic control unit 200 forms image data by imaging the reflection intensity profile of each A line.

[Operation control unit]
The configuration of the arithmetic control unit 200 will be described. The arithmetic control unit 200 analyzes the interference signal input from the detector 125 to form an OCT image of the eye E to be inspected. The arithmetic processing for forming the OCT image is the same as that of the conventional swept source type ophthalmic apparatus.

Further, the arithmetic control unit 200 controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100. For example, the arithmetic control unit 200 causes the display device 3 to display the OCT image of the eye E to be inspected.

The arithmetic control unit 200 includes, for example, a microprocessor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, and the like, as in a conventional computer. A computer program for controlling the ophthalmologic device 1 is stored in a storage device such as a hard disk drive. The arithmetic control unit 200 may include various circuit boards, for example, circuit boards for forming OCT images. Further, the arithmetic control unit 200 may include an operation device (input device) such as a keyboard and a mouse, and a display device such as an LCD.

[Processing system]
The configuration of the processing system of the ophthalmic apparatus 1 will be described with reference to FIGS. 3 and 4. In addition, in FIG. 3, some components of the ophthalmic apparatus 1 are omitted, and components particularly necessary for explaining this embodiment are selectively shown.

(Control unit)
The arithmetic control unit 200 includes a control unit 210, an image forming unit 220, and a data processing unit 230. The control unit 210 includes, for example, a microprocessor, RAM, ROM, a hard disk drive, a communication interface, and the like. The control unit 210 is provided with a main control unit 211 and a storage unit 212.

The function of the main control unit 211 is realized by, for example, a microprocessor (that is, a "processor"). A computer program for controlling the ophthalmologic device is stored in the storage unit 212 in advance. This computer program includes various light source control programs, optical scanner control programs, various detector control programs, image forming programs, data processing programs, user interface programs, and the like. When the main control unit 211 operates according to such a computer program, the control unit 210 executes the control process.

(Main control unit)
The main control unit 211 performs the above-mentioned various controls. In particular, as shown in FIG. 3, the main control unit 211 controls the focusing drive units 31A and 43A of the fundus camera unit 2, the CCD image sensors 35 and 38, the LCD 39, the optical path length changing unit 41, and the optical scanner 42. .. Further, the main control unit 211 controls the optical system drive unit 1A. Further, the main control unit 211 controls the light source unit 101 of the OCT unit 100, the optical path length changing unit 114, the detector 125, the DAQ 130, and the like.

The focusing drive unit 31A receives control from the main control unit 211 and moves the photographing focusing lens 31 along the optical axis of the photographing optical system 30. The focusing drive unit 31A is provided with a holding member for holding the photographing focusing lens 31, an actuator for generating a driving force for moving the holding member, and a transmission mechanism for transmitting the driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is composed of, for example, a combination of gears or a rack and pinion. As a result, the focusing drive unit 31A controlled by the main control unit 211 moves the photographing focusing lens 31, so that the focusing position of the photographing optical system 30 is changed. The focusing drive unit 31A may move the photographing focusing lens 31 along the optical axis of the photographing optical system 30 manually or by operating the operation unit 240B of the user.

The focusing drive unit 43A receives control from the main control unit 211 and moves the OCT focusing lens 43 along the optical axis (optical path of the measurement light) of the interference optical system in the OCT unit 100. The focusing drive unit 43A is provided with a holding member for holding the OCT focusing lens 43, an actuator for generating a driving force for moving the holding member, and a transmission mechanism for transmitting the driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is composed of, for example, a combination of gears or a rack and pinion. As a result, the focusing drive unit 43A controlled by the main control unit 211 moves the OCT focusing lens 43, so that the focusing position of the measurement light is changed. The focusing drive unit 43A may move the OCT focusing lens 43 along the optical axis of the interference optical system by manual operation or operation with respect to the operation unit 240B by the user.

The main control unit 211 can control the exposure time (charge accumulation time), sensitivity, frame rate, etc. of the CCD image sensor 35. The main control unit 211 can control the exposure time, sensitivity, frame rate, etc. of the CCD image sensor 38.

The main control unit 211 can control the display of the fixative and the visual acuity measurement target on the LCD 39. As a result, it becomes possible to switch the optotype presented to the eye E to be inspected and to change the type of optotype. Further, by changing the display position of the optotype on the LCD 39, it is possible to change the optotype presentation position with respect to the eye E to be inspected.

By controlling the optical path length changing unit 41, the main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measured light LS. The main control unit 211 controls the optical path length changing unit 41 so that the target portion of the eye E to be inspected is drawn in a predetermined range in the frame of the OCT image. Specifically, the main control unit 211 controls the optical path length changing unit 41 so that the target portion of the eye E to be inspected is drawn at a predetermined z position (position in the depth direction) in the frame of the OCT image. Is possible.

By controlling the optical scanner 42, the main control unit 211 can change the projection position of the measured light LS on the fundus Ef of the eye E to be inspected or the anterior eye portion.

The optical system drive unit 1A three-dimensionally moves the optical system (optical system shown in FIGS. 1 and 2) provided in the ophthalmic appliance 1. The optical system drive unit 1A moves the optical system under the control of the main control unit 211. This control is used in alignment and tracking. Tracking is to move the device optical system according to the movement of the eye E to be inspected. When tracking is performed, alignment and focusing are performed in advance. Tracking maintains a suitable positional relationship in which alignment and focus are achieved by moving the device optical system in real time according to the position and orientation of the eye E to be inspected based on an image obtained by shooting a moving image of the eye E to be inspected. It is a function.

By controlling the light source unit 101, the main control unit 211 can control switching between turning on and off the light L0, changing the amount of light of the light L0, and the like.

By controlling the optical path length changing unit 114, the main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measured light LS. The main control unit 211 controls the optical path length changing unit 114 so that the target portion of the eye E to be inspected is drawn in a predetermined range within the frame of the OCT image. Specifically, the main control unit 211 can control the optical path length changing unit 114 so that the target portion of the eye E to be inspected is drawn at a predetermined z position in the frame of the OCT image. By controlling at least one of the optical path length changing units 41 and 114, the main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measured light LS. Hereinafter, the main control unit 211 will be described as adjusting the optical path length difference between the measurement light LS and the reference light LR by controlling only the optical path length changing unit 114, but controls only the optical path length changing unit 41. Thereby, the optical path length difference between the reference light LR and the measurement light LS may be adjusted.

The main control unit 211 can control the exposure time (charge accumulation time), sensitivity, frame rate, etc. of the detector 125. Further, the main control unit 211 can control the DAQ 130.

As shown in FIG. 4, the main control unit 211 includes an alignment control unit 211A, a tracking control unit 211B, and a scan control unit 211C.

The alignment control unit 211A controls the execution of alignment for aligning the device optical system (optical system shown in FIGS. 1 and 2) with respect to the eye E to be inspected. For example, an alignment target by the alignment optical system 50 and a split target by the focus optical system 60 are projected on the eye E to be inspected. An optotype image based on an alignment optotype is drawn on the anterior eye portion image of the eye E to be inspected obtained by the photographing optical system 30. For example, the data processing unit 230, which will be described later, obtains the amount of movement of the device optical system based on the positional deviation of the optotype image with respect to the reference position in the front eye portion image. The alignment control unit 211A can control the optical system drive unit 1A based on the obtained movement amount.

Further, the alignment control unit 211A can control the optical system drive unit 1A based on the anterior eye portion image of the eye to be inspected E obtained by the photographing optical system 30. The alignment control unit 211A specifies, for example, a feature position in the anterior eye portion image of the eye E to be inspected obtained by the photographing optical system 30, so that the amount of deviation between the specified feature position and the predetermined target position is cancelled. The amount of movement of the optical system of the device is obtained. The alignment control unit 211A aligns the device optical system with respect to the eye E to be inspected by controlling the optical system drive unit 1A based on the obtained movement amount (xy direction). The target position may be a predetermined position or a position in the anterior eye portion image designated by using the operation unit 240B.

Similarly, the alignment control unit 211A can execute alignment by controlling the optical system drive unit 1A based on the fundus image of the eye E to be inspected obtained by the photographing optical system 30.

The alignment control unit 211A specifies, for example, the in-focus state (blurring condition) of the anterior eye portion image (or the fundus image) of the eye E to be inspected obtained by the photographing optical system 30, and the specified in-focus state is desired. It is possible to determine the amount of movement of the device optical system in the z direction so that it is in the focused state. The alignment control unit 211A controls the optical system drive unit 1A based on the obtained movement amount to align the device optical system with respect to the eye E to be inspected (z direction). It should be noted that the anterior segment of the eye is photographed from two or more cameras from different directions, the in-focus state is three-dimensionally specified from the two or more images provided with parallax, and the specified in-focus state is desired. The amount of movement of the device optical system in the z direction may be obtained so as to be in the focused state.

The tracking control unit 211B controls tracking of the anterior eye portion image (or fundus image) of the eye E to be inspected obtained by the photographing optical system 30. The tracking control unit 211B specifies, for example, a feature position in the anterior eye portion image (or fundus image) at a predetermined timing, and when the specified feature position changes, the deviation amount of the position is canceled. Find the amount of movement. The tracking control unit 211B controls tracking for the anterior eye portion image (or fundus image) by controlling the optical system drive unit 1A based on the obtained movement amount.

In this embodiment, the tracking control unit 211B performs tracking control by a method corresponding to an observation site (photographing site, measurement site, data collection site). When the front lens 23 is retracted from between the eye E to be inspected and the objective lens 22, the tracking control unit 211B performs tracking control in the fundus mode. When the anterior lens 23 is arranged between the eye to be inspected E and the objective lens 22, the tracking control unit 211B performs tracking control in the anterior eye portion mode.

(Fundus mode)
In the fundus mode, the tracking control unit 211B performs tracking control based on the fundus image of the eye E to be inspected obtained by the photographing optical system 30. The fundus images are acquired as a base image and a target image at different timings from each other. The base image corresponds to the reference image. That is, the tracking control unit 211B uses the base image, which is the fundus image of the eye E to be inspected, obtained in advance as a reference, and the position shift amount (position shift direction) of the target image, which is the fundus image obtained after the acquisition of the base image. It is possible to obtain (including) and perform tracking control based on the obtained amount of misalignment. The tracking control unit 211B can control the optical system drive unit 1A based on the obtained positional deviation amount.

The amount of misalignment of the target image with respect to the base image may be obtained by performing phase-limited correlation processing on the base image and the target image. In this case, the amount of misalignment is the amount of rotational movement in the subpixel level rotation direction (rotational direction about the axis in the z direction) between the base image and the target image at the subpixel level, the rotational movement direction thereof, and the base. It includes the amount of translation in the xy plane at the subpixel level between the image and the target image, the direction of translation thereof, and the like. Specifically, the data processing unit 230 calculates the rotational movement amount and the rotational movement direction between the base image and the target image at the subpixel level by phase-limited correlation processing, and the calculated rotational movement amount and rotational movement direction. Aligns the rotation direction between the base image and the target image based on. After that, the data processing unit 230 calculates the amount of translation and the direction of translation between the aligned base image and the target image at the subpixel level. Such a phase-limited correlation process is the same as the process disclosed in Japanese Patent Application Laid-Open No. 2015-043898.

(Anterior eye mode)
In the anterior segment mode, the tracking control unit 211B performs tracking control based on the anterior segment image of the eye E to be inspected obtained by the photographing optical system 30. The anterior eye image is acquired as a base image and a target image at different timings from each other. The base image corresponds to the reference image. That is, the tracking control unit 211B is based on the base image which is the anterior eye part image of the eye E to be inspected obtained in advance, and the position shift amount of the target image which is the anterior eye part image obtained after the acquisition of the base image. It is possible to obtain (including the misalignment direction) and perform tracking control based on the obtained misalignment amount. The amount of misalignment of the target image with respect to the base image may be obtained by performing phase-limited correlation processing on the base image and the target image. The tracking control unit 211B can control the optical system drive unit 1A based on the obtained positional deviation amount.

By controlling the optical scanner 42, the scan control unit 211C controls the projection position of the measured light LS in the horizontal or vertical direction (direction substantially orthogonal to the depth direction) of the observation site (anterior eye portion or fundus) of the eye to be inspected E. To change. The scan control unit 211C can control the start position and end position of each scan and the deflection angle of the measurement light LS for the optical scanner 42 based on the preset scan area and scan pattern.

In the embodiment, the scanning mode by the measurement light LS includes, for example, a horizontal scan, a vertical scan, a cross scan, a radial scan, a circular scan, a concentric circular scan, a spiral (swirl) scan, and the like. These scan modes are appropriately and selectively used in consideration of the observation site in the anterior eye portion or the fundus, the analysis target (net film thickness, etc.), the time required for the scan, the accuracy of the scan, and the like.

The horizontal scan changes the projection position of the measurement light LS in the horizontal direction (x direction). The horizontal scan also includes an embodiment in which the projection position of the measurement light LS is changed along a plurality of horizontally extending scan lines arranged in the vertical direction (y direction). In this aspect, it is possible to arbitrarily set the spacing between the scanning lines. Further, a three-dimensional image can be formed by sufficiently narrowing the interval between adjacent scanning lines (three-dimensional scanning). The same is true for vertical scans.

The cross scan changes the projection position of the measurement light LS along a cross-shaped locus composed of two linear loci (straight-line loci) orthogonal to each other. The radiation scan changes the projection position of the measurement light LS along a radial locus composed of a plurality of linear loci arranged via a predetermined angle. The cross scan is an example of a radiation scan.

The circular scan changes the projection position of the measured light LS along the trajectory of the circular shape. The concentric scan changes the projection position of the measured light LS along a plurality of circular loci arranged concentrically around a predetermined center position. The circle scan is considered to be a special case of the concentric circle scan. The spiral scan changes the projection position of the measured light LS along a spiral (spiral) trajectory while gradually reducing (or increasing) the radius of gyration.

In this embodiment, as will be described later, a state in which it is difficult to continue tracking control such as movement of the eye to be inspected or occurrence of blinking is detected as an abnormal state based on the image of the anterior eye portion or the image of the fundus. At least one of the tracking control unit 211B and the scan control unit 211C can execute the following control based on the above-mentioned abnormal state detection result.

When the above abnormality is not detected, the tracking control unit 211B controls the optical system drive unit 1A so that the device optical system follows the movement of the eye to be inspected based on the base image and the target image. On the other hand, when the above abnormality is detected, the scan control unit 211C measures at the start position of the first scan being executed at the acquisition timing of the target image or the second scan executed before the first scan. The optical scanner 42 is controlled to project the optical LS to re-execute the first scan or the second scan. Here, the first scan may be a horizontal scan, a vertical scan, a cross scan, a radial scan, a circular scan, a concentric circular scan, or a spiral scan. The second scan may be a scan executed immediately before the first scan or a scan executed two or more times before the first scan. The second scan may be a scan executed before the first scan for a predetermined time in consideration of the processing load and the complexity of control. The second scan, like the first scan, may also be a horizontal scan, a vertical scan, a cross scan, a radial scan, a circular scan, a concentric scan, or a spiral scan. The scan control unit 211C may re-execute the first scan or the second scan after the alignment of the device optical system with respect to the eye E to be inspected is completed by the alignment control unit 211A. The scan control unit 211C can execute rescan in units of scans in a direction intersecting the measurement light LS.

(Memory)
The storage unit 212 stores various data. The data stored in the storage unit 212 includes, for example, image data of an OCT image, image data of a fundus image and an anterior eye portion image, eye information to be inspected, and the like. The eye test information includes information about the subject such as the patient ID and name, and information about the test eye such as left eye / right eye identification information. The main control unit 211 can store the abnormality occurrence information described later in the storage unit 212 in association with the information to be examined. Further, the storage unit 212 stores data such as various programs and control information for operating the ophthalmic apparatus 1.

(Image forming part)
The image forming unit 220 forms image data of a tomographic image of the fundus Ef and the anterior eye portion based on the interference signal from the detector 125 (DAQ130). This process includes processing such as noise removal (noise reduction), filter processing, and FFT (Fast Fourier Transform). The image data acquired in this way is a data set containing a group of image data formed by imaging a reflection intensity profile in a plurality of A lines (paths of each measured light LS in the eye E to be inspected). be.

In order to improve the image quality, it is possible to superimpose (add and average) a plurality of data sets collected by repeating scanning with the same pattern multiple times.

Further, the image forming unit 220 can form an anterior eye portion image based on the detection result of the reflected light from the anterior eye portion of the eye E to be inspected by the CCD image sensor 35 or the CCD image sensor 38.

The image forming unit 220 includes, for example, the circuit board described above. In this specification, "image data" and "image" based on the "image data" may be equated with each other. In addition, the site of the eye E to be inspected and the image thereof may be equated.

(Data processing unit)
The data processing unit 230 performs various data processing (image processing) and analysis processing on the image formed by the image forming unit 220. For example, the data processing unit 230 executes correction processing such as image brightness correction and dispersion correction.

The data processing unit 230 can form volume data (voxel data) of the eye E to be inspected by executing known image processing such as interpolation processing for interpolating pixels between tomographic images. When displaying an image based on volume data, the data processing unit 230 performs rendering processing on the volume data to form a pseudo three-dimensional image when viewed from a specific line-of-sight direction.

The data processing unit 230 can align the fundus image (or the anterior eye part image) with the OCT image. When the fundus image (or anterior segment image) and the OCT image are acquired in parallel, since both optical systems are coaxial, the fundus image (or anterior segment image) acquired at the same time (almost). ) And the OCT image can be aligned with respect to the optical axis of the photographing optical system 30. Further, regardless of the acquisition timing of the fundus image (or the anterior segment image) and the OCT image, at least a part of the corresponding image region of the fundus Ef (or the anterior segment image) of the OCT image is projected onto the xy plane. It is also possible to align the OCT image and the fundus image (or the anterior segment image) by aligning the frontal image obtained with the fundus image (or the anterior segment image). This alignment method can be applied even when the optical system for acquiring the fundus image (or the image of the anterior segment of the eye) and the optical system for OCT are not coaxial. Even if both optical systems are not coaxial, if the relative positional relationship between the two optical systems is known, the same alignment as in the case of coaxial is executed with reference to this relative positional relationship. It is possible.

The data processing unit 230 includes an analysis unit 231. The analysis unit 231 performs an analysis process on the anterior eye portion image or the fundus image obtained by the photographing optical system 30. The analysis process includes a process of specifying a feature area and a feature position (feature point) in an image, a process of moving the eye E to be inspected, a process of detecting the occurrence of blinking or the occurrence of flare, and the like.

(Anterior eye mode)
In the anterior segment mode, the analysis unit 231 performs, for example, a process of specifying a feature region and a feature position in the anterior segment image.

For example, the analysis unit 231 can specify a predetermined region including a region corresponding to the pupil of the eye to be inspected E as a characteristic region in the anterior eye portion image. The tracking control unit 211B controls the optical system drive unit 1A based on the displacement of the feature region in the target image with respect to the feature region in the base image. Thereby, tracking based on the position of the feature area can be performed. The characteristic area may be a blood vessel, a diseased part, an iris area, or the like.

Further, by analyzing the base image and the target image, the analysis unit 231 can detect the occurrence of factors that hinder the tracking control, such as the movement of the eye E to be inspected and the occurrence of blinking. For example, the analysis unit 231 determines that the amount of movement of the eye E to be inspected is large when the amount of movement of the feature area in the target image with respect to the feature area in the base image is equal to or greater than a predetermined first threshold value, and an abnormal state that impedes tracking control. Detect as. Further, when the analysis unit 231 cannot specify (detect) a predetermined feature region in at least one of the base image and the target image, the analysis unit 231 determines that the eyelids are closed by blinking, and determines that the eyelids are closed as an abnormal state that impedes tracking control. Detect. Further, when the analysis unit 231 cannot identify (detect) at least a part of the boundary of the characteristic region (for example, the pupil region) in at least one of the base image and the target image, the analysis unit 231 determines that the eyelashes are covered. It is detected as an abnormal state that interferes with tracking control.

(Fundus mode)
In the fundus mode, the analysis unit 231 performs, for example, a process of specifying a feature region and a feature position in the fundus image.

For example, the analysis unit 231 can specify a predetermined region including a region corresponding to the optic nerve head or the fovea centralis as a characteristic region in the fundus image. The tracking control unit 211B controls the optical system drive unit 1A based on the displacement of the feature region in the target image with respect to the feature region in the base image. Thereby, tracking based on the position of the feature area can be performed. The characteristic region may be a blood vessel, a diseased part, or the like.

Further, as in the case of the anterior eye portion mode, the analysis unit 231 analyzes the base image and the target image to generate factors that hinder tracking control such as movement of the eye E to be inspected, blinking, and flare. Can be detected. For example, the analysis unit 231 determines that the amount of movement of the eye E to be inspected is large when the amount of movement of the feature area in the target image with respect to the feature area in the base image is equal to or greater than a predetermined second threshold value, and an abnormal state that impedes tracking control. Detect as. Further, the analysis unit 231 can specify (detect) a predetermined feature region by analyzing at least one luminance distribution (luminance information) of the base image and the target image. For example, when the brightness of the entire image is high (when the brightness is equal to or higher than a predetermined threshold level), the analysis unit 231 determines that the eyelids are closed due to blinking, and detects it as an abnormal state that impedes tracking control. For example, when the brightness of the entire image is low (when the brightness is equal to or less than a predetermined threshold level), the analysis unit 231 determines that the eyelashes are visualized and detects it as an abnormal state that impedes tracking control. For example, the analysis unit 231 determines that flare has occurred in the image when a partial region having high luminance exists, and detects it as an abnormal state that impedes tracking control.

The data processing unit 230 that functions as described above includes, for example, a microprocessor, RAM, ROM, a hard disk drive, a circuit board, and the like. A computer program that causes a microprocessor to execute the above functions is stored in a storage device such as a hard disk drive in advance.

(User interface)
The user interface 240 includes a display unit 240A and an operation unit 240B. The display unit 240A includes the display device and the display device 3 of the arithmetic control unit 200 described above. The operation unit 240B includes the operation device of the arithmetic control unit 200 described above. The operation unit 240B may include various buttons and keys provided on the housing of the ophthalmologic device 1 or on the outside. Further, the display unit 240A may include various display devices such as a touch panel provided on the housing of the fundus camera unit 2.

The display unit 240A and the operation unit 240B do not need to be configured as separate devices. For example, it is also possible to use a device such as a touch panel in which a display function and an operation function are integrated. In that case, the operation unit 240B includes the touch panel and a computer. The operation content for the operation unit 240B is input to the control unit 210 as an electric signal. Further, the graphical user interface (GUI) displayed on the display unit 240A and the operation unit 240B may be used to perform operations and information input.

The optical system shown in FIG. 1 (for example, the interference optical system included in the OCT unit 100) is an example of the “optical system” according to the embodiment. The optical system drive unit 1A is an example of the "moving mechanism" according to the embodiment. The photographing optical system 30 is an example of the “image acquisition unit” according to the embodiment. The analysis unit 231 is an example of the "abnormality detection unit" according to the embodiment. The base image is an example of the "reference image" according to the embodiment. The target image is an example of the "image of the eye to be inspected acquired by the image acquisition unit" according to the embodiment.

[Operation example]
An operation example of the ophthalmic apparatus according to the embodiment will be described.

FIG. 5 shows a flow chart showing an example of the operation of the ophthalmic appliance 1 according to the embodiment. In FIG. 8, it is assumed that the front lens 23 is arranged between the eye E to be inspected and the objective lens 22.

(S1: Start shooting the anterior eye)
First, acquisition of a near-infrared moving image of the anterior segment of the eye is started by continuously illuminating the anterior segment of the eye with illumination light from the observation light source 11 (which becomes near-infrared light by the visible cut filter 14). This near-infrared moving image is obtained in real time until the end of continuous illumination. The image of each frame constituting this moving image is temporarily stored in the frame memory (storage unit 212) and sequentially sent to the data processing unit 230.

An alignment target by the alignment optical system 50 and a split target by the focus optical system 60 are projected on the eye E to be inspected. Therefore, an alignment optotype and a split optotype are drawn on the near-infrared moving image. Alignment and focusing can be performed using these optotypes. In addition, a fixative target by the LCD 39 is also projected on the eye E to be inspected. The subject is instructed to stare at this fixative.

(S2: Alignment)
The data processing unit 230 sequentially analyzes the frames obtained by photographing the eye E to be inspected as a moving image by the optical system, obtains the position of the optotype image based on the alignment optotype, and calculates the movement amount of the optical system. The control unit 210 performs auto-alignment by controlling the optical system drive unit 1A based on the movement amount of the optical system calculated by the data processing unit 230.

(S3: Focusing)
The data processing unit 230 sequentially analyzes the frames obtained by photographing the eye E to be inspected as a moving image by the optical system, obtains the position of the split optotype, and the amount of movement of the photographing focusing lens 31 and the OCT focusing lens 43. Is calculated. The control unit 210 performs autofocus by controlling the focusing drive units 31A and 43A based on the amount of movement of the photographing focusing lens 31 and the OCT focusing lens 43 calculated by the data processing unit 230.

(S4: Start tracking)
Subsequently, the control unit 210 starts auto-tracking. Specifically, the data processing unit 230 analyzes in real time the frames sequentially obtained by shooting a moving image of the eye E to be inspected by the optical system, and monitors the movement (change in position) of the eye E to be inspected. The control unit 210 controls the optical system drive unit 1A so as to move the optical system according to the position of the eye E to be sequentially acquired. As a result, the optical system can be made to follow the movement of the eye E to be inspected in real time, and it is possible to maintain a suitable positional relationship in which alignment and focus are in focus.

(S5: Set the scan area)
The control unit 210 causes the display unit 240A to display the near-infrared moving image in real time. The user sets a scan region on this near-infrared moving image by using the operation unit 240B. The scan area to be set may be a one-dimensional area or a two-dimensional area.

(S6: OCT measurement)
The control unit 210 controls the light source unit 101 and the optical path length changing unit 41, and also controls the optical scanner 42 based on the scan area set in step S5 to perform OCT measurement of the anterior eye portion. The image forming unit 220 forms a tomographic image of the anterior eye portion based on the obtained detection signal. When the scanning mode is a three-dimensional scan, the data processing unit 230 forms a three-dimensional image of the anterior eye portion based on a plurality of tomographic images formed by the image forming unit 220. When an abnormal state that impedes tracking control is detected as described above, the control unit 210 causes the rescan to be executed. As a result, the influence on image acquisition and measurement can be reduced. This is the end of this operation example (end).

FIG. 6 shows a flow chart of a processing example of step S6 of FIG. In FIG. 6, it is assumed that the anterior eye portion image, which is a base image, has been acquired in advance.

(S11: Get the image)
First, the control unit 210 uses the photographing optical system 30 to acquire an anterior eye portion image as a target image.

(S12: Analysis)
Subsequently, the control unit 210 causes the analysis unit 231 to analyze the already acquired frontal eye image as the base image and the anterior eye image acquired in step S11, thereby controlling the tracking as described above. It is made to detect whether or not it is an abnormal state that inhibits.

(S13: Anomaly detection?)
When an abnormal state is detected by the analysis process in step S12 (S13: Y), the operation of the ophthalmic appliance 1 shifts to step S14. When it is detected by the analysis process in step S12 that the state is not abnormal (S13: N), the operation of the ophthalmic appliance 1 shifts to step S17.

(S14: Alignment)
When an abnormal state is detected in step S13 (S13: Y), the control unit 210 executes alignment in the same manner as in step S2. As a result, the positional relationship of the device optical system with respect to the eye E to be inspected becomes substantially the same as after the alignment is completed in step S2.

(S15: Optical scanner reset)
Subsequently, the control unit 210 projects the measurement light LS to the start position of the first scan being executed at the image acquisition timing in step S11 or the second scan executed before the first scan, and the optical scanner 42. To reset.

(S16: Start rescan)
Next, the control unit 210 causes the first scan or the second scan to be re-executed from the start position reset in step S15.

(S17: Displacement is calculated)
When it is detected in step S13 that it is not in an abnormal state (S13: N), the control unit 210 determines the characteristic region in the anterior eye part image as the already acquired base image and the anterior eye part image acquired in step S11. The analysis unit 231 is made to calculate the displacement of the feature region in the above.

(S18: Movement control)
The control unit 210 controls the optical system drive unit 1A based on the displacement calculated in step S17, so that the device optical system follows the movement of the eye E to be inspected.

(S19: Scan finished?)
Following step S16 or step S18, the control unit 210 determines whether or not the scan is completed. For example, the control unit 210 determines whether or not the scan is completed based on the preset scan area and scan pattern. When it is determined that the scan is completed (S19: Y), the operation of the ophthalmic appliance 1 shifts to step S20. When it is determined that the scan is not completed (S19: N), the operation of the ophthalmic appliance 1 shifts to step S11.

(S20: Save)
When it is determined in step S19 that the scan is completed (S19: Y), the control unit 210 uses the abnormality occurrence information including the cause of the abnormality state as the subject information based on the abnormality state detection process in step S13. It is associated and saved in the storage unit 212. As described above, the analysis unit 231 detects the movement of the eye E to be inspected and the occurrence of blinking as an abnormal state. The analysis unit 231 can generate abnormality occurrence information including occurrence cause information corresponding to the processing in which the abnormality state is detected. When the analysis unit 231 continuously detects an abnormal state of the same type a predetermined number of times during measurement of the subject, the analysis unit 231 can generate abnormality occurrence information including the occurrence cause information corresponding to the abnormal state. Is. Note that step S20 may be executed at any position between steps S13 and S19. This is the end of the process of step S6 (end).

Although FIG. 6 has described the case where the observation site is the anterior eye portion, the same applies to the case where the observation site is the fundus. In this case, the abnormal state is detected by the detection method corresponding to the fundus image as described above.

Further, the abnormality occurrence information stored in the storage unit 212 in step S20 of FIG. 6 may be used, for example, at the time of rescanning in step S16 of FIG. 6 or at the time of remeasurement of the subject.

For example, when it is determined that the line-of-sight shift (movement of the eye to be inspected E) is likely to occur based on the abnormality occurrence information, the control unit 210 controls the LCD 39 at the time of rescanning in step S16 or at the time of remeasurement of the subject. By controlling the movement of the fixation position, the occurrence of line-of-sight deviation may be suppressed.

For example, when it is determined that blinking is likely to occur based on the abnormality occurrence information, the control unit 210 identifies and identifies the blinking occurrence cycle at the time of rescanning in step S16 or at the time of remeasurement of the subject. The optical scanner 42 may be controlled to scan in synchronization with the generation cycle.

For example, when it is determined that the eyelashes are likely to be visualized in the image based on the abnormality occurrence information, the control unit 210 provides information for urging the examiner to open the eyelids prior to the rescanning or the remeasurement of the subject. It may be output to the UI unit 240.

For example, when it is determined that flare is likely to occur based on the abnormality occurrence information, the control unit 210 sets the optical system drive unit 1A to adjust the working distance prior to the rescan or the remeasurement of the subject. You may control it.

[effect]
The ophthalmic apparatus according to the embodiment will be described.

The ophthalmic apparatus (1) according to the embodiment includes an optical system (optical system shown in FIG. 1, an interference optical system included in the OCT unit 100), a moving mechanism (optical system driving unit 1A), and an image acquisition unit (photographing optics). It includes a system 30), an abnormality detection unit (analysis unit 231), a scan control unit (211C), and a tracking control unit (211B). The optical system includes an optical scanner (42), deflects light (L0) from a light source (light source unit 101) by an optical scanner and projects it onto the eye to be inspected (E), and light based on the return light from the eye to be inspected (E). Interference light LC, part of the return light) is received. The moving mechanism moves relatively between the eye to be inspected and the optical system. The image acquisition unit acquires an image of the eye to be inspected. The abnormality detection unit detects an abnormality (abnormal state) based on the reference image (base image) and the image of the eye to be inspected (target image) acquired by the image acquisition unit. When an abnormality is detected by the abnormality detection unit, the scan control unit emits a light source at the start position of the first scan being executed for the eye to be inspected or the second scan executed before the first scan at the image acquisition timing. The optical scanner is controlled to project light from the first scan or the second scan. The tracking control unit controls the movement mechanism so that the optical system follows the movement of the eye to be inspected based on the reference image and the image of the eye to be inspected when the abnormality is not detected by the abnormality detection unit.

According to such a configuration, an abnormality is detected during tracking control based on the reference image and the image of the eye to be inspected acquired by the image acquisition unit, and is being executed for the eye to be inspected at the acquisition timing of the image of the eye to be inspected. Since the first scan or the second scan of the above is re-executed, even if a factor that obstructs the tracking control occurs during the tracking control, it is possible to reduce the influence on accurate image acquisition and measurement by simple control. become able to.

Further, the ophthalmic apparatus according to the embodiment includes an alignment control unit (211A) that performs alignment of the optical system with respect to the eye to be inspected by controlling a movement mechanism when an abnormality is detected, and the scan control unit includes an alignment control unit. After the alignment by the control unit is completed, the first scan or the second scan may be re-executed.

According to such a configuration, the first scan or the second scan is re-executed after the alignment is completed, so that the data acquired before the re-scan and the data obtained by the re-executed scan are consistent. It will be possible to contribute to accurate image acquisition and measurement.

Further, in the ophthalmic apparatus according to the embodiment, the image acquisition unit acquires the anterior eye portion image of the eye to be inspected, and the tracking control unit performs a movement mechanism based on the amount of deviation of the feature position in the reference image and the anterior eye portion image. You may control it.

According to such a configuration, even if the eye to be inspected moves during the tracking control based on the image of the anterior segment of the eye, it is possible to reduce the influence on accurate image acquisition and measurement by simple control.

Further, in the ophthalmic apparatus according to the embodiment, the abnormality detecting unit may detect an abnormality when the deviation amount of the feature position is equal to or more than the first threshold value.

According to such a configuration, even if the eye to be inspected moves with a large deviation in the feature position during tracking control based on the anterior eye image, the influence on accurate image acquisition and measurement can be reduced by simple control. Will be able to.

Further, in the ophthalmic apparatus according to the embodiment, the abnormality detection unit may detect an abnormality when the feature position is not detected in the reference image or the anterior eye portion image.

With such a configuration, even if blinking occurs during tracking control based on the front eye image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmic apparatus according to the embodiment, the abnormality detection unit may detect an abnormality when at least a part of the boundary of the feature region is not detected in the reference image or the anterior eye portion image.

With such a configuration, even if the eyelashes are visualized in the image during the tracking control based on the anterior eye image, it is possible to reduce the influence on accurate image acquisition and measurement by simple control.

Further, in the ophthalmic apparatus according to the embodiment, the image acquisition unit acquires the fundus image (target image) of the eye to be inspected, and the tracking control unit performs phase-limited correlation processing on the reference image and the fundus image. The movement mechanism may be controlled so as to cancel the obtained misalignment amount.

With such a configuration, even if the eye to be inspected moves during tracking control based on the fundus image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmic apparatus according to the embodiment, the abnormality detecting unit may detect an abnormality when the feature position is not detected based on the luminance information of the reference image or the fundus image.

With such a configuration, even if the occurrence of blinking or the depiction of eyelashes is detected during tracking control based on the fundus image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control. Become.

Further, in the ophthalmic apparatus according to the embodiment, the abnormality detection unit may detect an abnormality when flare is detected in a reference image or a fundus image.

With such a configuration, even if the occurrence of flare is detected during the tracking property based on the fundus image, it becomes possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmic apparatus according to the embodiment, when an abnormality is detected by the abnormality detection unit, the control unit (210) stores the abnormality occurrence information including the cause of the abnormality in the storage unit (212) in association with the subject information. , Main control unit 211) may be included.

With such a configuration, the cause of the abnormality during tracking control can be identified, so that measures can be taken to prevent the occurrence of the same abnormality when the subject is remeasured. become.

Further, the control method of the ophthalmologic apparatus according to the embodiment includes an optical scanner (42), and the light (measurement light LS) from the light source (light source unit 101) is deflected by the optical scanner and projected onto the eye to be inspected (E). The optical system (the optical system shown in FIG. 1, the interference optical system included in the OCT unit 100) that receives light (interference light LC) based on the return light from the eye to be inspected is relatively different from the eye to be inspected and the optical system. It is a control method of an ophthalmic apparatus including a moving moving mechanism (optical system driving unit 1A). The control method of the ophthalmic apparatus includes an image acquisition step, an abnormality detection step, a scan control step, and a tracking control step. The image acquisition step acquires an image (target image) of the eye to be inspected. The abnormality detection step detects an abnormality based on a reference image (base image) and an image of the eye to be inspected. When an abnormality is detected, the scan control step projects the light at the start position of the first scan being executed for the eye to be inspected or the second scan executed before the first scan at the image acquisition timing. The optical scanner is controlled so as to re-execute the first scan or the second scan. The tracking control step controls the movement mechanism so that the optical system follows the movement of the eye to be inspected based on the reference image and the image of the eye to be inspected when an abnormality is not detected.

According to such a configuration, the abnormality is detected during the tracking control based on the reference image and the image of the eye to be inspected acquired by the image acquisition unit, and the first execution is being executed for the eye to be inspected at the image acquisition timing. Since the scan or the second scan is re-executed, even if the eye to be inspected moves or blinks during tracking control, it is possible to reduce the influence on accurate image acquisition and measurement with simple control. Become.

Further, the control method of the ophthalmic apparatus includes an alignment control step of performing alignment of the optical system with respect to the eye to be inspected by controlling the movement mechanism when an abnormality is detected, and in the scan control step, the position in the alignment control step. After the alignment is completed, the first scan or the second scan may be re-executed.

According to such a configuration, the first scan or the second scan is re-executed after the alignment is completed, so that the data acquired before the re-scan and the data obtained by the re-executed scan are consistent. It will be possible to contribute to accurate image acquisition and measurement.

<Modification example>
The embodiments shown above are merely examples for carrying out the present invention. A person who intends to carry out the present invention can make arbitrary modifications, omissions, additions, etc. within the scope of the gist of the present invention.

In the above-described embodiment, the case where the configuration of the optical system is the configuration shown in FIG. 1 or FIG. 2 has been described, but the configuration of the optical system according to the embodiment is not limited to this. The optical system according to the embodiment may include an optical system for irradiating a treatment site on the fundus with a laser beam, an optical system for moving an optotype while the eye to be examined is fixed, and the like.

In the above-described embodiment, the case where the imaging site is the fundus or the anterior segment of the eye has been described, but the imaging site is not limited to the fundus or the anterior segment of the eye. Further, the imaging region may be three or more regions.

1 Ophthalmology device 1A Optical system drive unit 10 Illumination optical system 23 Front lens 30 Imaging optical system 35 CCD image sensor 100 OCT unit 210 Control unit 211 Main control unit 211A Alignment control unit 211B Tracking control unit 211C Scan control unit 212 Storage unit 220 Image formation unit 230 Data processing unit 231 Analysis unit E Eye to be inspected

Claims (10)

An optical system including an optical scanner, which deflects light from a light source by the optical scanner and projects it onto an eye to be inspected, and receives light based on the return light from the eye to be inspected.
A moving mechanism that relatively moves the eye to be inspected and the optical system,
An image acquisition unit that acquires an image of the eye to be inspected,
An abnormality detection unit that detects an abnormality based on a reference image and an image of the eye to be inspected acquired by the image acquisition unit, and an abnormality detection unit.
An alignment control unit that executes alignment of the optical system with respect to the eye to be inspected by controlling the movement mechanism when an abnormality is detected by the abnormality detection unit.
After the alignment by the alignment control unit is completed, the first scan being executed for the eye to be inspected or the second scan executed before the first scan is started at the acquisition timing of the image of the eye to be inspected. A scan control unit that controls the optical scanner to project light from the light source to a position to re-execute the first scan or the second scan.
A tracking control unit that controls the movement mechanism so that the optical system follows the movement of the eye to be inspected based on the reference image and the image of the eye to be inspected when an abnormality is not detected by the abnormality detection unit. ,
Including
After re-executing the first scan or the second scan, the image acquisition unit reacquires the image of the eye to be inspected, and the abnormality detection unit detects the abnormality using the re-acquired image. , Ophthalmology equipment. The image acquisition unit acquires an image of the anterior eye portion of the eye to be inspected, and obtains an image of the anterior segment of the eye.
The ophthalmic apparatus according to claim 1, wherein the tracking control unit controls the movement mechanism based on the amount of deviation of the feature positions in the reference image and the anterior eye portion image. The ophthalmic apparatus according to claim 2, wherein the abnormality detecting unit detects the abnormality when the deviation amount of the feature position is equal to or greater than a first threshold value. The ophthalmic apparatus according to claim 2 or 3, wherein the abnormality detecting unit detects the abnormality when a feature point is not detected in the reference image or the anterior eye portion image. Any of claims 2 to 4, wherein the abnormality detecting unit detects the abnormality when at least a part of the boundary of the characteristic region is not detected in the reference image or the anterior eye portion image. The ophthalmic apparatus according to paragraph 1. The image acquisition unit acquires a fundus image of the eye to be inspected and obtains an image of the fundus.
Claim 1 is characterized in that the tracking control unit controls the movement mechanism so as to cancel the amount of misalignment obtained by performing phase-limited correlation processing on the reference image and the fundus image. The ophthalmic device described in. The ophthalmic apparatus according to claim 6, wherein the abnormality detecting unit detects the abnormality based on the luminance information of the reference image or the fundus image. The ophthalmic apparatus according to claim 6 or 7, wherein the abnormality detecting unit detects the abnormality when flare is detected in the reference image or the fundus image. Claims 1 to claim include a control unit that, when the abnormality is detected by the abnormality detection unit, stores the abnormality occurrence information including the cause of the abnormality in the storage unit in association with the subject information. 8. The ophthalmic apparatus according to any one of 8. An optical system including an optical scanner, which deflects light from a light source by the optical scanner and projects it onto an eye to be inspected, and receives light based on the return light from the eye to be inspected.
A moving mechanism that relatively moves the eye to be inspected and the optical system,
Is a control method for ophthalmic appliances including
The image acquisition step of acquiring the image of the eye to be inspected, and
An abnormality detection step for detecting an abnormality based on a reference image and an image of the eye to be inspected,
An alignment control step that executes alignment of the optical system with respect to the eye to be inspected by controlling the movement mechanism when the abnormality is detected.
After the alignment in the alignment control step is completed, the first scan being executed for the eye to be inspected or the second scan executed before the first scan is started at the acquisition timing of the image of the eye to be inspected. A scan control step that controls the optical scanner to project light from the light source to a position to re-execute the first scan or the second scan.
A tracking control unit step that controls the movement mechanism so that the optical system follows the movement of the eye to be inspected based on the reference image and the image of the eye to be inspected when the abnormality is not detected.
Including
After the first scan or the second scan is re-executed, the image acquisition step re-acquires the image of the eye to be inspected, and the abnormality detection step detects the abnormality using the re-acquired image. , Control method of ophthalmic device.

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