JP6934747B2 - Ophthalmic device and its control method - Google Patents

Description

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

In recent years, OCT (Optical Coherence Tomography), which forms an image showing the surface morphology and internal morphology of an object to be measured by using a light beam from a laser light source or the like, has attracted attention. Since OCT does not have invasiveness to the human body like X-ray CT (Computed Tomography), it is expected to be applied especially in the medical field and the biology field. For example, in the field of ophthalmology, devices for imaging the fundus and cornea and measuring the optical characteristics of the eye to be inspected have been put into practical use.

The measurement target of the ophthalmic apparatus using such OCT is the living eye. The living eye is constantly moving due to body movements, eye movements, and pulsations. Therefore, the eye to be inspected is moving even during the OCT measurement. For example, when the eye to be inspected moves in the traveling direction of the measurement light (depth direction and depth direction of the eye to be inspected), the part of interest is drawn at the end of the imaging range (frame) by OCT measurement, and in some cases, the part of interest is drawn. It may come off the frame.

Therefore, in the ophthalmic apparatus, before performing the OCT measurement, the optical path length of the reference light and the optical path length of the measurement light are set according to the eye to be inspected so that the region of interest of the eye to be inspected is drawn at a suitable position in the frame. The difference is adjusted (eg, Patent Documents 1 to 5). In adjusting the optical path length difference, a position where the brightness value is maximized (a position where the detection intensity of the interference light is maximized) in the depth direction of the tomographic image of the eye to be inspected is used. The position where such a brightness value is maximized is a position corresponding to the retinal pigment epithelium (RPE) of the eye to be inspected.

JP-A-2007-185244 Japanese Unexamined Patent Publication No. 2007-215733 Japanese Unexamined Patent Publication No. 2014-2006788 Japanese Unexamined Patent Publication No. 2014-200679 Japanese Unexamined Patent Publication No. 2014-200680

By the way, in recent years, ophthalmic devices using OCT have a wide range in the depth direction of the eye to be inspected because parameters representing the structure of the eye to be inspected such as the axial length are measured at once and a wide range of the eye to be inspected is imaged. It is required that OCT measurement is possible within a range.

However, there is a trade-off relationship between the depth range of OCT measurement and the measurement accuracy, and if OCT measurement is performed over a wide range, it may be difficult to identify the layered region of the retina such as the retinal pigment epithelium of the eye to be examined. .. In such a case, it is not possible to properly change the difference between the optical path length of the reference light and the optical path length of the measurement light before performing the OCT measurement, and the region of interest is not visualized in the image of the eye to be inspected or is desired. It may not be possible to measure the parameter itself.

The present invention has been made in view of such circumstances, and an object of the present invention is to image a region of interest of an eye to be inspected at an appropriate position even when the depth range of OCT measurement is widened. It is an object of the present invention to provide an ophthalmic apparatus capable of measuring and a control method thereof.

The ophthalmic apparatus according to the first aspect of the embodiment divides the light from the light source into a reference light and a measurement light, irradiates the test eye with the measurement light, and together with the return light of the measurement light from the test eye. An interference optical system that detects interference light with the reference light, an optical path length changing unit that relatively changes the optical path length of the reference light and the optical path length of the measurement light, and the interference light by the interference optical system. Control to control the brightness profile generation unit that generates the brightness profile in the optical axis direction of the interference optical system based on the detection result and the optical path length changing unit based on the change in the brightness value in the optical axis direction in the brightness profile. Includes part and.

Further, in the first aspect, the ophthalmic apparatus according to the second aspect of the embodiment includes an image forming portion that forms a tomographic image of the eye to be inspected based on the detection result of the interference light by the interference optical system, and the interference The optical system includes an optical scanner that deflects the measurement light in a scan direction that intersects the optical axis direction, and the brightness profile generator is in the scan direction for each of a plurality of positions in the optical axis direction in the tomographic image. The brightness profile may be generated by integrating the brightness values.

In addition, the ophthalmic apparatus according to the third aspect of the embodiment has, in the first or second aspect, a specific portion that specifies the position of the deepest region of the eye to be inspected in the optical axis direction based on the change in the luminance value. Including, the control unit may control the optical path length changing unit based on the position specified by the specific unit.

Further, in the ophthalmic apparatus according to the fourth aspect of the embodiment, in the third aspect, the specific portion uses the position where the absolute value of the change amount of the luminance value in the predetermined change direction is the maximum as the position of the deepest region. It may be specified.

Further, in the ophthalmic apparatus according to the fifth aspect of the embodiment, in the third or fourth aspect, the control unit changes the optical path length so that the deepest region is drawn within a predetermined range of the frame of the image. The unit may be controlled.

In addition, the ophthalmic apparatus according to the sixth aspect of the embodiment includes a calculation unit that sequentially obtains the difference between two luminance values adjacent to each other in the optical axis direction in the luminance profile in any of the first to fifth aspects. Including, the control unit may obtain the difference obtained by the calculation unit as a change in the luminance value, and control the optical path length changing unit based on the obtained difference.

Further, in the ophthalmic apparatus according to the seventh aspect of the embodiment, in any one of the first to sixth aspects, the optical path length changing portion is arranged in the optical path of the reference light, and is arranged along the optical path of the reference light. The control unit includes a movable reference mirror and a moving mechanism for moving the reference mirror along the optical path of the reference light, and the control unit controls the moving mechanism to measure the optical path length of the reference light and the measurement. The optical path length of light may be changed relatively.

Further, in the ophthalmic apparatus according to the eighth aspect of the embodiment, in any one of the first to seventh aspects, the interference optical system repeatedly scans the eye to be inspected with the measurement light, and the control unit causes the control unit. , The optical path length changing portion may be repeatedly controlled based on the change in the brightness value.

The control method of the ophthalmic apparatus according to the ninth aspect of the embodiment is to divide the light from the light source into a reference light and a measurement light, irradiate the test eye with the measurement light, and return the measurement light from the test eye. A detection step of detecting interference light between light and the reference light, a brightness profile generation step of generating a brightness profile in the depth direction of the eye to be inspected based on the detection result of the interference light, and the depth in the brightness profile. The step includes an optical path length difference changing step of relatively changing the optical path length of the reference light and the optical path length of the measurement light based on the change in the brightness value in the longitudinal direction.

In addition, the method for controlling the ophthalmic apparatus according to the tenth aspect of the embodiment includes, in the ninth aspect, a specific step of specifying the position of the deepest region of the eye to be inspected in the depth direction based on the change in the luminance value. In the optical path length difference changing step, the optical path length of the reference light and the optical path length of the measurement light are drawn so that the deepest region is drawn within a predetermined range of the frame of the image based on the position in the depth direction. And may be changed relatively.

According to the present invention, an ophthalmic apparatus capable of imaging and measuring a region of interest of an eye to be inspected at an appropriate position even when the depth range of OCT measurement is widened, and a control method thereof. Will be able to provide.

It is the schematic which shows an example of the structure of the optical system of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the optical system of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the control system of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the control system of the ophthalmic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation of the ophthalmic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation of the ophthalmic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation of the ophthalmic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation of the ophthalmic apparatus which concerns on embodiment. It is a flow figure which shows an example of the operation of the ophthalmic apparatus which concerns on embodiment. It is a flow figure which shows an example of the operation of the ophthalmic apparatus which concerns on embodiment.

An example of an embodiment of the ophthalmic apparatus according to the present invention will be described in detail with reference to the drawings. It should be noted that the description contents of the documents cited in this specification and arbitrary known techniques can be incorporated into the following embodiments.

The ophthalmic apparatus according to the embodiment is a measuring device having at least a function of executing OCT and capable of acquiring information about the object to be measured by executing OCT on the object to be measured. Hereinafter, the case where the ophthalmic apparatus according to the embodiment images the living eye by performing OCT on the living eye as the object to be measured 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 the living eye such as the axial length by performing OCT on the living eye.

The ophthalmologic apparatus according to the embodiment is an ophthalmologic apparatus that combines a Fourier domain OCT and a fundus camera. This ophthalmic device has the ability to perform swept source OCT, but 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 passing through the object to be measured to interfere with the reference light to generate interference light. Then, this interference light is detected by a balanced photodiode or the like, and the detection data collected in response to the sweeping of the wavelength and the scanning 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 measurement light and 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 imaging 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". Sometimes referred to as "optical path".

[composition]
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 It means a processing circuit including Programmable Logic Device), FPGA (Field Programmable Gate Array), and the like. The processor realizes the function according to the embodiment by reading and executing, for example, a program stored in a storage circuit or a storage device.

[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 E to be inspected. 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 fluorescence image, an indocyanine green fluorescence image, and a spontaneous fluorescence 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 E to be inspected, and guides the measurement light passing through the eye E to be inspected 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 is focused for photographing. 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, an observation image of the anterior eye portion of the eye E to be inspected is displayed.

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 condensing lens 37 of the CCD image sensor 38. An image is formed on the light receiving surface. An image (captured 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 photographing light source.

The LCD (Liquid Crystal Display) 39 displays a fixation target and a visual acuity measurement target. The fixation target is a target 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 fixation target on the screen of the LCD 39, the fixation 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 holes 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 hole portion, and a part of the light passes through the dichroic mirror 55 and passes through the photographing focusing lens 31. The corneal reflex 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 received image (alignment optotype) by the CCD image sensor 35 is displayed on the display device 3 together with the observed 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 can move along the optical path of the illumination optical system 10. The photographing focusing lens 31 can move 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 light 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 luminous fluxes by the split optotype 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, is once imaged on the reflecting surface of the reflecting rod 67 by the condenser lens 66, and is reflected. 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 received as a pair of split target lights. 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 image (a pair of split optotype images) received by the CCD image sensor 35 is displayed on the display device 3 together with the observed image. The arithmetic control unit 200 analyzes the positions of the pair of split optotype images 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 imaging surface of the CCD image sensor 35. Further, focusing may be performed manually (by operating the operation unit 242 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 substantially coupled to 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 conjugate with the split optotype 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, separated 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 so as to coincide with each other in the vertical direction, for example. 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 conjugated, 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 fundus photography. The dichroic mirror 46 reflects light in the wavelength band used for OCT and transmits light for fundus photography. 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 exit 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 luminous flux, and collects the return light of the measurement light from the eye E to be examined at 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 with 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.

[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 eye E to be inspected 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, similarly 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 is invisible to the human eye.

The light L0 output from the light source unit 101 is guided by the optical fiber 102 to the polarization controller 103, 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 by the optical fiber 110 to the collimator 111 to become a parallel luminous 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 converted 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 luminous flux to a focused luminous 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 measurement 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 light 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 measurement 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 generates interference light by synthesizing (interfering with) the measurement light LS incidented through the optical fiber 128 and the reference light LR incidented via the optical fiber 121. 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 by these. The detector 125 sends the detection result (interference signal) to the DAQ (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 the combined light. Generate. The DATA 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.

[Calculation 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, similarly to a conventional computer. A computer program for controlling the ophthalmic apparatus 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.

[Control system]
The configuration of the control system of the ophthalmic apparatus 1 will be described with reference to FIGS. 3 and 4. 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.

(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 lens 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 lens driving 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 lens driving 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 lens driving 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 lens driving 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 242 of the user.

The lens driving 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 lens driving 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 lens driving 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 lens driving 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 242 by the user.

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

The main control unit 211 can control the display of the fixation target and the visual acuity measurement target on the LCD 39. As a result, it is possible to switch the optotype presented to the eye E to be inspected and 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 measurement 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 within 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.

The main control unit 211 can change the scanning position of the measurement light LS in the fundus Ef of the eye E to be inspected by controlling the optical scanner 42.

The optical system drive unit 1A three-dimensionally moves the optical system (optical system shown in FIGS. 1 and 2) provided in the ophthalmic apparatus 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 capturing 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 measurement 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 measurement 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. Therefore, the optical path length difference between the reference light LR and the measurement light LS may be adjusted.

The optical path length difference adjustment by the main control unit 211 is performed based on the luminance profile in the z direction generated from the detection result of the interference light obtained by the OCT measurement. In this embodiment, the luminance profile in the z direction is array data of a plurality of luminance values corresponding to a plurality of positions in the z direction. The luminance profile may be data in which a plurality of luminance values corresponding to a plurality of positions in the z direction are arranged, or may be data representing changes in the plurality of luminance values. Such a luminance profile is generated from a tomographic image (A scan image or B scan image) of the eye E to be inspected. The brightness profile may be generated from the detection result by the detector 125. The main control unit 211 adjusts the optical path length difference based on the change (change direction, change amount) of the brightness value in the z direction in the brightness profile. Specifically, the region of interest of the eye E to be inspected is specified based on the change in the luminance value in the z direction, and the optical path length difference is adjusted so that the identified region of interest is drawn at a predetermined z position in the frame. Be struck. As a region of interest, for example, there is the deepest region of the fundus Ef (the deepest region of the image of the fundus Ef, the region including the maximum z position where OCT measurement is possible in the fundus Ef).

By repeatedly acquiring the tomographic image of the eye E to be inspected, generating a brightness profile from the acquired tomographic image, and repeatedly adjusting the optical path length difference based on the generated brightness profile, a desired region of interest can be obtained. It is possible to maintain the state depicted at a predetermined z position.

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.

(Memory)
The storage unit 212 stores various types of data. The data stored in the storage unit 212 includes, for example, image data of an OCT image, image data of a fundus 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. 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 the image data of the tomographic image of the fundus Ef 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 including a group of image data formed by imaging the reflection intensity profile in a plurality of A lines (paths of each measurement 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 a plurality of times.

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. 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 and the OCT image. When the fundus image and the OCT image are acquired in parallel, since both optical systems are coaxial, the fundus image and the OCT image acquired at the same time (almost) are taken as the optical axis of the photographing optical system 30. Can be aligned with reference to. Further, regardless of the acquisition timing of the fundus image and the OCT image, the alignment of the frontal image obtained by projecting at least a part of the image region corresponding to the fundus Ef of the OCT image onto the xy plane and the fundus image is performed. By doing so, it is also possible to align the OCT image and the fundus image. This alignment method can be applied even when the optical system for acquiring the fundus image 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.

As shown in FIG. 4, the data processing unit 230 is provided with a luminance profile generation unit 231, a calculation unit 232, and a specific unit 233.

The brightness profile generation unit 231 generates a brightness profile in the z direction from the tomographic image of the eye E to be inspected. The calculation unit 232 obtains a change (change direction, change amount) of the brightness value in the z direction in the brightness profile generated by the brightness profile generation unit 231. The identification unit 233 specifies the position of the region of interest of the eye E to be inspected in the z direction based on the change in the luminance value in the z direction obtained by the calculation unit 232. The specific unit 233 according to the embodiment can specify the position of the deepest region of the fundus Ef in the z direction.

The luminance profile generation unit 231 can generate a luminance profile from the luminance values at a plurality of z positions in the A scan image generated based on the detection result of the A scan obtained by the detector 125, for example. Further, the luminance profile generation unit 231 has, for example, crossing the luminance values at a plurality of z positions in the B scan image generated based on the detection result by the detector 125 in the intersecting directions (for example, the x direction or the x direction) intersecting the A scan direction. It is possible to generate a luminance profile by obtaining a statistical value in the y direction). Here, the statistical value means a value obtained by a known statistical process. Statistical values according to this embodiment include integrated values, average values, and the like.

Alternatively, the luminance profile generation unit 231 may directly generate a luminance profile in the z direction from the detection result of the interference light by the detector 125. For example, the brightness profile generation unit 231 analyzes the detection result of the A scan obtained by the detector 125 to obtain the reflected light intensity at a plurality of z positions, and assigns the brightness value corresponding to the obtained reflected light intensity. Generates a brightness profile. Further, the luminance profile generation unit 231 analyzes, for example, the detection results of the A scan obtained by the detector 125 for the plurality of scan positions in the crossing direction in the fundus Ef, and the reflected light intensity at the plurality of z positions of each A line. A brightness profile may be generated by obtaining a brightness value corresponding to the obtained reflected light intensity and obtaining a statistical value for the brightness values at a plurality of z positions in the intersection direction.

In the following, it is assumed that the luminance profile generation unit 231 includes the integration unit 2311. The integrating unit 2311 integrates the luminance values of the plurality of z positions in the B-scan image formed by the image forming unit 220 in the direction intersecting the A-scan direction to obtain the integrated value of the luminance values. That is, the brightness profile generation unit 231 generates a brightness profile in which integrated values of brightness values are arranged for a plurality of z positions in the B-scan image obtained by executing OCT.

The calculation unit 232 obtains a change in the brightness value in the z direction in the brightness profile generated by the brightness profile generation unit 231. The calculation unit 232 can obtain the change direction of the luminance value in the z direction and the amount of change thereof. For example, the calculation unit 232 obtains the change direction of the brightness value in the z direction and the amount of change thereof by sequentially obtaining the difference between the two brightness values adjacent to each other in the acquired brightness profile. The change direction corresponds to the sign (+,-) of the obtained difference value. The amount of change corresponds to the absolute value of the obtained difference value. Further, for example, the calculation unit 232 may specify the change direction of the luminance value and the amount of change thereof by obtaining the rate of change of the luminance value corresponding to the change of the z position based on the acquired luminance profile. .. The direction of change corresponds to the code of the obtained ratio. The amount of change corresponds to the absolute value of the calculated ratio.

In the following, it is assumed that the calculation unit 232 includes the difference calculation unit 2321. The difference calculation unit 2321 obtains the difference between two luminance values adjacent to each other in the luminance profile in the luminance profile. That is, the calculation unit 232 obtains the change direction of the luminance value in the z direction and the amount of change thereof by sequentially obtaining the difference between the two luminance values adjacent to each other in the luminance profile.

FIG. 5 shows an explanatory diagram of the luminance profile according to the embodiment. FIG. 5 shows the depth direction (z direction) in the vertical direction and the xy scan direction (scan direction on the xy plane) intersecting the z direction in the horizontal direction.

When the B-scan image IMG1 formed by the image forming unit 220 is acquired, the luminance profile generation unit 231 is in a direction (xy scan direction in FIG. 5) that intersects the depth direction (z direction) for a plurality of z positions. A brightness profile is generated by integrating the brightness values. As shown in FIG. 5, the luminance profile generation unit 231 integrates the luminance values of each pixel of the B scan image IMG1 in the xy scan direction at the z position z0 to obtain the luminance value La0, and obtains the luminance value La0, and z1 (z0 <z1). The brightness values of each pixel of the B scan image IMG1 are integrated in the xy scan direction to obtain the brightness value La1. The brightness value of each pixel is integrated to obtain the brightness value LaN.

The calculation unit 232 generates a difference profile as shown in FIG. 5 by sequentially obtaining the difference between two brightness values adjacent to each other in the z direction in the brightness profile generated by the brightness profile generation unit 231. In FIG. 5, the calculation unit 232 obtains the difference value D0 (= La0-La1) between the luminance value La0 corresponding to the z position z0 and the luminance value La1 corresponding to the z position z1, and the luminance value corresponding to the z position z1. The difference value D1 (= La1-La0) between La1 and the luminance value La2 corresponding to the z position z2 is obtained, and ..., the luminance values La (N-1) and z corresponding to the z position z (N-1). The difference value D (N-1) (= LaN-La (N-1)) from the luminance value LaN corresponding to the position zN is obtained.

As shown in FIG. 5, the identification unit 233 specifies the position of the predetermined portion of the eye E to be inspected in the z direction based on the difference profile representing the change in the luminance value in the z direction obtained by the calculation unit 232.

FIG. 6 shows an explanatory diagram of the difference profile according to the embodiment. In FIG. 6, the difference value obtained by the calculation unit 232 is represented by the vertical axis, and the depth position is represented by the horizontal axis. In FIG. 6, the difference values corresponding to the depth positions shown in FIG. 5 are indicated by the same reference numerals. In FIG. 6, for convenience of illustration in FIG. 5, it is assumed that the luminance value of the black pixel is higher than the luminance value of the white pixel.

The identification unit 233 specifies the position where the absolute value of the change amount of the luminance value in the predetermined change direction is the maximum as the position of the deepest region. The identification unit 233 specifies the depth position corresponding to the difference value having the code corresponding to the predetermined change direction based on the difference profile obtained by the calculation unit 232. Subsequently, the identification unit 233 specifies the depth position where the absolute value is the maximum among the difference values having the above symbols as the position of the deepest region of the eye E to be inspected.

For example, in the case of FIGS. 5 and 6, the region of the symbol “+” indicates that the region changes from a pixel having a high luminance value (black pixel) to a pixel having a low luminance value (white pixel). The area where “−” is “−” indicates that the area changes from a pixel having a low luminance value to a pixel having a high luminance value. Therefore, the z position Pz1 shown in FIGS. 5 and 6 is specified as a position included in the deepest region of the eye E to be inspected.

In addition, the specific unit 233 can analyze the difference profile or the luminance profile according to how the brightness value corresponding to the region of interest changes, and specify the z position of the region of interest. For example, the specific unit 233 searches the difference profile in order from the shallow z position, and first sets the z position Pz0, which is the absolute value of the difference value equal to or larger than the threshold value with the sign “−”, in the shallowest region in the eye E to be inspected. It can be specified as a position.

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 241 and an operation unit 242. The display unit 241 includes the display device and the display device 3 of the arithmetic control unit 200 described above. The operation unit 242 includes the operation device of the arithmetic control unit 200 described above. The operation unit 242 may include various buttons and keys provided on the housing of the ophthalmic apparatus 1 and on the outside. Further, the display unit 241 may include various display devices such as a touch panel provided on the housing of the fundus camera unit 2.

The display unit 241 and the operation unit 242 do not need to be configured as separate devices. For example, it is 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 242 includes the touch panel and a computer. The operation content for the operation unit 242 is input to the control unit 210 as an electric signal. Further, the graphical user interface (GUI) displayed on the display unit 241 and the operation unit 242 may be used to perform operations and information input.

7 and 8 show an explanatory diagram of the operation of the ophthalmic apparatus 1 according to the embodiment. FIG. 7 shows an example of a tomographic image of the fundus Ef drawn in the frame before adjusting the optical path length difference between the reference light LR and the measurement light LS. FIG. 8 shows an example of a tomographic image of the fundus Ef drawn in the frame after adjusting the optical path length difference between the reference light LR and the measurement light LS.

For example, it is assumed that a tomographic image in which the deepest region of the eye E to be inspected (for example, the deep region of the fundus Ef such as RPE) is visualized at the visualization position as shown in FIG. 7 is acquired. At this time, the luminance profile generation unit 231 generates the luminance profile as described above (FIG. 5). As described above, the calculation unit 232 generates a difference profile by sequentially obtaining the difference between two brightness values adjacent to each other in the z direction in the brightness profile (FIG. 5). As described above, the identification unit 233 specifies the position of the deepest region of the eye E to be inspected.

The control unit 210 controls the optical path length changing unit 114 so that the deepest region of the eye E to be inspected specified by the specific unit 233 is drawn at a predetermined z position in the frame, thereby and the optical path length of the reference light LR. The optical path length of the measurement light LS is relatively changed. For example, the storage unit 212 stores in advance control information in which the optical path length difference adjustment amount between the reference light LR and the measurement length LS is associated with each of the z positions in the plurality of deepest regions with respect to the predetermined reference z position. As a predetermined reference z position, there is a zero delay position in which the optical path length of the reference light LR is equal to the optical path length of the measurement light LS. When the control unit 210 acquires the z position of the deepest region of the eye E to be inspected specified by the specific unit 233, the control unit 210 refers to the control information stored in the storage unit 212 and adjusts the optical path length associated with the z position. It is determined, and the optical path length changing unit 114 is controlled based on the determined optical path length adjustment amount. As a result, as shown in FIG. 8, a tomographic image in which the deepest region of the eye E to be inspected is drawn at a predetermined z position in the frame is acquired.

The storage unit 212 may store in advance control information in which the control contents for the optical path length changing unit 114 are associated with each of the z positions in the plurality of deepest regions with respect to the predetermined reference z position. In this case, when the control unit 210 acquires the z position of the deepest region of the eye E to be inspected specified by the specific unit 233, the control unit 210 refers to the control information stored in the storage unit 212 and the control content associated with the z position. The optical path length changing unit 114 is controlled based on the above.

The optical system included in the OCT unit 100 shown in FIG. 2 is an example of the “interference optical system” according to the embodiment. The corner cube of the optical path length changing unit 114 is an example of the “reference mirror” according to the embodiment. The moving mechanism that moves the corner cube of the optical path length changing unit 114 is an example of the “moving mechanism” according to the embodiment.

[Operation example]
The operation of the ophthalmic apparatus 1 according to the embodiment will be described. In the following, it is assumed that the region of interest of the eye E to be inspected is the deepest region in the tomographic image of the fundus Ef.

FIG. 9 shows an example of the operation of the ophthalmic apparatus 1 according to the embodiment. FIG. 9 shows a flow chart of an operation example when an OCT image and a fundus image of the eye E to be inspected are acquired.

(S1)
First, the main control unit 211 acquires an image of the anterior segment of the eye by controlling the imaging optical system 30 to photograph the anterior segment of the eye E to be inspected.

(S2)
The main control unit 211 moves the optical system three-dimensionally by controlling the optical system drive unit 1A based on the image of the anterior segment acquired in S1, and positions the optical system with respect to the eye E to be inspected. Alignment is performed (x-direction, y-direction, and z-direction orthogonal to both x-direction and y-direction).

(S3)
The main control unit 211 sets the optical scanner 42 so that the predetermined initial position becomes the scanning position.

(S4)
The main control unit 211 turns on the light source unit 101 and controls the optical scanner 42 to start scanning the fundus Ef of the eye E to be inspected with the measurement light LS based on the light L0 from the light source unit 101. The image forming unit 220 forms an OCT image of the fundus Ef based on the detection result of the interference light by the detector 125.

(S5)
The main control unit 211 aligns the focus direction of the retina from the image of the anterior eye portion obtained by the photographing optical system 30. As a result, the position of the optical system included in the OCT unit 100 in the optical axis direction can be finely adjusted.

(S6)
The main control unit 211 starts adjusting the drawing position in the frame of the region of interest of the eye E to be inspected. From S6 onward, the tomographic image of the eye E to be inspected is repeatedly acquired, a luminance profile is generated from the acquired tomographic image, and the optical path length difference adjustment is repeatedly performed based on the generated luminance profile. As a result, the state in which the region of interest of the eye E to be inspected is visualized at a predetermined z position is maintained. Details of S6 will be described later.

(S7)
The main control unit 211 changes the focal position of the optical system included in the OCT unit 100 based on the detection result of the interference light by the detector 125. For example, the main control unit 211 controls the lens drive unit 43A so that the amplitude of the detection signal of a predetermined interference light is maximized, and moves the OCT focusing lens 43 in the optical axis direction to move the focal position of the optical system. To change.

(S8)
The main control unit 211 again controls the optical scanner 42 to start scanning the fundus Ef of the eye E to be inspected with the measurement light LS based on the light L0 from the light source unit 101. The image forming unit 220 forms an OCT image of the fundus Ef based on the detection result of the interference light by the detector 125. In S8, as shown in FIG. 8, an OCT image in which the deepest region of the eye E to be inspected is drawn at a predetermined z position in the frame is acquired.

(S9)
The main control unit 211 acquires a fundus image by controlling the photographing optical system 30 and photographing the fundus Ef of the eye E to be inspected. This completes the operation of the ophthalmic apparatus 1 (end).

FIG. 10 shows a flow chart of an operation example of S6 of FIG.

(S21)
In S6 of FIG. 9, when the adjustment of the drawing position in the frame of the region of interest of the eye E to be inspected is started, the main control unit 211 causes the luminance profile generation unit 231 to generate the luminance profile as shown in FIG. The brightness profile generation unit 231 acquires an OCT image generated based on the detection result of the interference light obtained in advance in the detection step in the scan of S4 or the repetitive measurement light LS. The luminance profile generation unit 231 generates a luminance profile by integrating the luminance values in the xy scan direction for a plurality of z positions in the acquired OCT image (luminance profile generation step).

(S22)
Next, as shown in FIG. 5, the main control unit 211 causes the calculation unit 232 to generate a difference profile by sequentially obtaining the difference between two luminance values adjacent to each other in the z direction in the luminance profile generated in S21. ..

(S23)
As described above, the main control unit 211 causes the specific unit 233 to specify the z position in the deepest region of the eye E to be inspected. Based on the difference profile generated in S22, the identification unit 233 specifies, for example, the depth position where the absolute value is the largest among the difference values whose symbols are "+" as the z position in the deepest region of the eye E to be inspected (specification). Step).

(S24)
The main control unit 211 refers to the control information stored in the storage unit 212, acquires the control content associated with the z position in the deepest region of the eye E to be inspected specified in S23, and is based on the acquired control content. The optical path length difference adjustment amount between the reference light LR and the measurement light LS is determined.

(S25)
The main control unit 211 controls the optical path length changing unit 114 based on the optical path length difference adjusting amount determined in S24 so that the deepest region of the eye E to be inspected is drawn at a predetermined z position in the frame. The optical path length difference between the optical LR and the measured optical LS is changed (optical path length difference changing step). For example, it is possible to repeatedly scan the fundus Ef of the eye E to be inspected with the measurement light LS, and execute S21 to S25 when a tomographic image is acquired to repeatedly adjust the optical path length difference.

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

The ophthalmic apparatus (1) according to the embodiment includes an interference optical system (an optical system included in the OCT unit 100), an optical path length changing unit (at least one of the optical path length changing units 41 and 114), and a brightness profile generation unit (231). And a control unit (210, main control unit 211). The interference optical system divides the light (L0) from the light source (light source unit 101) into the reference light (LR) and the measurement light (LS), irradiates the measurement light on the eye to be inspected (E), and emits the measurement light from the eye to be inspected. The interference light (LC) between the return light of the measurement light and the reference light is detected. The optical path length changing unit relatively changes the optical path length of the reference light and the optical path length of the measurement light. The brightness profile generation unit generates a brightness profile in the optical axis direction (z direction, depth direction) of the interference optical system based on the detection result of the interference light by the interference optical system. The control unit controls the optical path length changing unit based on the change (change direction, change amount) of the brightness value in the optical axis direction in the brightness profile.

In such a configuration, the interference optical system generates a brightness profile in the optical axis direction of the interference optical system based on the detection result of the interference light between the reference light and the measurement light passing through the eye to be inspected, and the generated brightness profile. The difference in optical path length between the reference light and the measurement light is changed based on the change in the brightness value in the optical axis direction in. As a result, it is not necessary to specify the portion having the maximum luminance value in the OCT image, and the depiction position and the measurable position of the region of interest of the eye to be inspected can be changed. Therefore, it is possible to provide an ophthalmic apparatus capable of changing the visualization position and the measurable position with respect to the region of interest of the eye to be inspected even when the depth range of OCT measurement is widened and the measurement accuracy is lowered. become. As a result, it is possible to provide an ophthalmic apparatus capable of imaging and measuring a region of interest of an eye to be inspected at an appropriate position even when the depth range of OCT measurement is widened. For example, even when OCT measurement is performed in a so-called full range, the region of interest of the eye to be inspected can be imaged or measured at an appropriate position.

Further, the ophthalmic apparatus according to the embodiment may include an image forming unit (220). The image forming unit forms a tomographic image of the eye to be inspected based on the detection result of the interference light by the interference optical system. The interferometric optics may include an optical scanner (42). The optical scanner deflects the measurement light in the scanning direction (xy scanning direction) intersecting the optical axis direction. The luminance profile generation unit can generate a luminance profile by integrating the luminance values in the scanning direction for each of the plurality of positions (z positions) in the optical axis direction in the tomographic image.

According to such a configuration, since the brightness profile is generated from the tomographic image formed by the image forming portion, it is possible to easily change the visualization position and the measurable position with respect to the region of interest of the eye to be inspected. It will be possible to provide various ophthalmic devices.

In addition, the ophthalmic apparatus according to the embodiment may include a specific unit (233). The identification unit specifies the position of the deepest region of the eye to be inspected in the optical axis direction based on the change in the brightness value in the brightness profile. The control unit can control the optical path length changing unit based on the position specified by the specific unit.

According to such a configuration, the position of the deepest region of the eye to be inspected in the optical axis direction is specified based on the change in the brightness value in the brightness profile, so that the depth range of OCT measurement is widened and the measurement accuracy is improved. Even if it is lowered, it becomes possible to provide an ophthalmic apparatus capable of changing the visualization position and the measurable position with respect to the deepest region of the eye to be inspected.

Further, in the ophthalmic apparatus according to the embodiment, the specific unit may specify the position where the absolute value of the change amount of the luminance value in the predetermined change direction is the maximum as the position of the deepest region.

According to such a configuration, since the position where the absolute value of the change amount is the maximum is specified in the predetermined change direction in the luminance profile, it is possible to specify the deepest region of the eye to be inspected by a simple process. Become. As a result, even if the depth range of OCT measurement is widened and the measurement accuracy is lowered, an ophthalmic apparatus capable of changing the visualization position and the measurable position with respect to the deepest region of the eye to be inspected is provided. You will be able to.

Further, in the ophthalmic apparatus according to the embodiment, the control unit may control the optical path length changing unit so that the deepest region is drawn within a predetermined range of the frame of the image.

According to such a configuration, even when the depth range of the OCT measurement is widened and the measurement accuracy is lowered, it is possible to acquire an OCT image in which the region of interest is drawn at a desired position of the frame of the image.

Further, the ophthalmic apparatus according to the embodiment may include a calculation unit (232). The calculation unit sequentially obtains the difference between two brightness values adjacent to each other in the brightness profile in the optical axis direction. The control unit can obtain the difference obtained by the calculation unit as a change in the luminance value, and can control the optical path length changing unit based on the obtained difference.

According to such a configuration, the change in the luminance value is specified by a simple calculation of the difference value. Therefore, even if the depth range of the OCT measurement is widened and the measurement accuracy is lowered, the change can be performed by a simple process. It will be possible to provide an ophthalmic apparatus capable of changing the visualization position and the measurable position with respect to the region of interest for optometry.

Further, in the ophthalmic apparatus according to the embodiment, the optical path length changing unit may include a reference mirror (corner cube) and a moving mechanism. The reference mirror is arranged in the optical path of the reference light and can move along the optical path of the reference light. The moving mechanism moves the reference mirror along the optical path of the reference light. The control unit can relatively change the optical path length of the reference light and the optical path length of the measurement light by controlling the moving mechanism.

According to such a configuration, the reference optical path length is changed with a simple configuration and control, so that even if the depth range of OCT measurement is widened and the measurement accuracy is lowered, the area of interest of the eye to be inspected can be seen. It is possible to simplify the configuration and control of the ophthalmic apparatus that can change the drawing position and the measurable position.

Further, in the ophthalmic apparatus according to the embodiment, the interference optical system repeatedly scans the eye to be inspected with the measurement light, and the control unit repeatedly controls the optical path length changing unit based on the above-mentioned change in the brightness value. You may.

According to such a configuration, it is possible to provide an ophthalmic apparatus capable of maintaining a state in which the region of interest of the eye to be inspected is visualized at a desired depth position.

The control method of the ophthalmic apparatus (ophthalmic apparatus 1) according to the embodiment includes a detection step, a brightness profile generation step, and an optical path length difference changing step. In the detection step, the light (L0) from the light source (light source unit 101) is divided into the reference light (LR) and the measurement light (LS), the measurement light is applied to the eye to be inspected (E), and the measurement from the eye to be inspected is performed. The interference light (LC) between the return light of the light and the reference light is detected. In the brightness profile generation step, a brightness profile in the depth direction (z direction) of the eye to be inspected is generated based on the detection result of the interference light. In the optical path length difference changing step, the optical path length of the reference light and the optical path length of the measurement light are relatively changed based on the change (change direction, amount of change) of the brightness value in the depth direction in the brightness profile.

In such a configuration, the interference optical system detects the interference light between the reference light and the measurement light passing through the eye to be inspected, and based on the detection result, a brightness profile in the optical axis direction of the interference optical system is generated and generated. The optical path length difference between the measurement light and the reference light is changed based on the change in the brightness value in the optical axis direction in the obtained brightness profile. As a result, it is possible to change the depiction position and the measurable position of the region of interest of the eye to be inspected without specifying the region having the maximum luminance value in the OCT image. Therefore, it is possible to provide an ophthalmic apparatus capable of changing the visualization position and the measurable position with respect to the region of interest of the eye to be inspected even when the depth range of OCT measurement is widened and the measurement accuracy is lowered. become. As a result, even when the depth range of OCT measurement is widened, it is possible to image or measure the region of interest of the eye to be inspected at an appropriate position.

Moreover, the control method of the ophthalmic apparatus according to the embodiment may include a specific step. In the specific step, the position in the depth direction of the deepest region of the eye to be inspected is specified based on the change in the brightness value. In the optical path length difference changing step, the optical path length of the reference light and the optical path length of the measurement light are relatively changed so that the deepest region is drawn within a predetermined range of the frame of the image based on the position in the depth direction. can do.

According to such a configuration, the depth position of the deepest region of the eye to be inspected is specified based on the change in the brightness value in the brightness profile, and the deepest position is within a predetermined range of the frame of the image based on the specified depth position. Since the optical path length of the reference light and the optical path length of the measurement light are changed relatively so that the region is drawn, even if the depth range of the OCT measurement is widened and the measurement accuracy is lowered, the image can be displayed. It is possible to acquire an OCT image in which the deepest region of the eye to be examined is drawn at a desired position of the frame.

<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.

A computer program for realizing the above embodiment can be stored in any computer-readable recording medium. Examples of the recording medium include semiconductor memory, optical disk, magneto-optical disk (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), magnetic storage medium (hard disk / floppy (registered trademark) disk / ZIP, etc.) and the like. Can be used.

1 Ophthalmology device 2 Eye fundus camera unit 41, 114 Optical path length changing unit 42 Optical scanner 100 OCT unit 200 Calculation control unit 210 Control unit 211 Main control unit 212 Storage unit 220 Image formation unit 230 Data processing unit 231 Brightness profile generation unit 232 Calculation unit 233 Specific unit 2311 Integration unit 2321 Difference calculation unit E Eye to be inspected Ef Fundus LC Interference light LR Reference light LS Measurement light

Claims (10)

Interfering optical system that divides the light from the light source into reference light and measurement light, irradiates the test eye with the measurement light, and detects the interference light between the return light of the measurement light from the test eye and the reference light. When,
An image forming unit that forms a tomographic image of the eye to be inspected based on the detection result of the interference light by the interference optical system.
An optical path length changing unit that relatively changes the optical path length of the reference light and the optical path length of the measurement light,
A luminance profile generation unit that generates a luminance profile in the optical axis direction of the interference optical system based on the detection result of the interference light by the interference optical system.
A control unit that controls the optical path length changing unit based on a change in the brightness value in the optical axis direction in the brightness profile, and a control unit.
Only including,
The interferometric optical system includes an optical scanner that deflects the measurement light in a scanning direction that intersects the optical axis direction.
The brightness profile generation unit is an ophthalmic apparatus that generates the brightness profile by integrating brightness values in the scan direction for each of a plurality of positions in the tomographic image in the optical axis direction. Includes a specific portion that specifies the position of the deepest region of the eye to be inspected in the optical axis direction based on the change in the brightness value.
The ophthalmic apparatus according to claim 1, wherein the control unit controls the optical path length changing unit based on the position specified by the specific unit. The ophthalmic apparatus according to claim 2 , wherein the specific unit specifies a position where the absolute value of the change amount of the luminance value in a predetermined change direction is maximum as the position of the deepest region. The ophthalmic apparatus according to claim 2 or 3 , wherein the control unit controls the optical path length changing unit so that the deepest region is drawn within a predetermined range of an image frame. Interfering optical system that divides the light from the light source into reference light and measurement light, irradiates the test eye with the measurement light, and detects the interference light between the return light of the measurement light from the test eye and the reference light. When,
An optical path length changing unit that relatively changes the optical path length of the reference light and the optical path length of the measurement light,
A luminance profile generation unit that generates a luminance profile in the optical axis direction of the interference optical system based on the detection result of the interference light by the interference optical system.
A control unit that controls the optical path length changing unit based on a change in the brightness value in the optical axis direction in the brightness profile, and a control unit.
A calculation unit that sequentially obtains the difference between two brightness values adjacent to each other in the brightness profile in the optical axis direction ,
Including
The control unit is an ophthalmic apparatus that obtains a difference obtained by the calculation unit as a change in the luminance value and controls the optical path length changing unit based on the obtained difference. The optical path length changing part is
A reference mirror arranged in the optical path of the reference light and movable along the optical path of the reference light,
A moving mechanism that moves the reference mirror along the optical path of the reference light,
Including
One of claims 1 to 5 , wherein the control unit relatively changes the optical path length of the reference light and the optical path length of the measurement light by controlling the moving mechanism. The ophthalmic device described in. The interferometric optical system repeatedly scans the eye to be inspected with the measurement light.
The ophthalmic apparatus according to any one of claims 1 to 6 , wherein the control unit repeatedly controls the optical path length changing unit based on a change in the brightness value. The light from the light source is divided into a reference light and a measurement light, the measurement light is deflected in a scanning direction intersecting the traveling direction of the measurement light to irradiate the eye to be inspected, and the measurement light is returned from the eye to be inspected. A detection step for detecting the interference light between the light and the reference light, and
An image formation step of forming a tomographic image of the eye to be inspected based on the detection result of the interference light,
A luminance profile generation step of generating a luminance profile in the depth direction of the eye to be inspected by integrating luminance values in the scanning direction for each of a plurality of positions in the traveling direction in the tomographic image.
An optical path length difference changing step of relatively changing the optical path length of the reference light and the optical path length of the measurement light based on the change in the brightness value in the depth direction in the brightness profile.
Including a control method for an ophthalmologic apparatus. A detection step in which the light from the light source is divided into a reference light and a measurement light, the measurement light is irradiated to the eye to be inspected, and the return light of the measurement light from the eye to be inspected and the interference light between the reference light are detected. ,
A luminance profile generation step for generating a luminance profile in the depth direction of the eye to be inspected based on the detection result of the interference light, and a luminance profile generation step.
In the brightness profile, the difference between two brightness values adjacent to each other in the depth direction is sequentially obtained, the obtained difference is obtained as a change in the brightness value, and the optical path length of the reference light is obtained based on the obtained difference. An optical path length difference changing step that relatively changes the optical path length of the measured light, and
Methods of controlling ophthalmic devices, including. Including a specific step of identifying the position of the deepest region of the eye to be inspected in the depth direction based on the change in the brightness value.
In the optical path length difference changing step, the optical path length of the reference light and the optical path length of the measurement light are set so that the deepest region is drawn within a predetermined range of the frame of the image based on the position in the depth direction. The control method of the ophthalmic apparatus according to claim 8 or 9, wherein the method is relatively changed.

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