JP2018192082A - Ophthalmologic apparatus and control method thereof - Google Patents

Abstract

To provide an ophthalmologic apparatus which can image and measure a portion of interest of an eye to be examined at a proper position even when the depth range of OCT measurement becomes wide, and a control method thereof.SOLUTION: An ophthalmologic apparatus includes an interference optical system, an optical path length change part, a luminance profile generation part and a control part. The interference optical system divides the light from a light source into reference light and measurement light, emits the measurement light to an eye to be examined, and detects the interference light between the return light of the measurement light from the eye to be examined and the reference light. The optical path length change part relatively changes the optical path length of the reference light and the optical path length of the measurement light. The luminance profile generation part generates the luminance profile in the optical axis direction of the interference optical system on the basis of the detection result of the interference light by the interference optical system. The control part controls the optical path length change part on the basis of the change in the luminance value in the optical axis direction in the luminance profile.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ophthalmologic apparatus and a control method thereof.

  In recent years, OCT (Optical Coherence Tomography), which forms an image representing the surface form and internal form of an object to be measured using a light beam from a laser light source or the like, has attracted attention. Since OCT has no invasiveness to the human body like X-ray CT (Computed Tomography), it is expected to be applied particularly in the medical field and the biological field. For example, in the field of ophthalmology, apparatuses for imaging the fundus and cornea and measuring optical characteristics of the eye to be examined have been put into practical use.

  A measurement target of such an ophthalmologic apparatus using OCT is a living eye. The living eye constantly moves due to body movement, eye movement, pulsation, and the like. Therefore, the eye to be examined is moving even during OCT measurement. For example, when the subject's eye moves in the direction in which the measurement light travels (the depth direction and depth direction of the subject's eye), the region of interest is depicted at the end of the imaging range (frame) by OCT measurement. It may come off the frame.

  Therefore, in the ophthalmologic 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 in accordance with the eye so that the attention site of the eye to be examined is depicted at a suitable position in the frame. The difference is adjusted (for example, Patent Documents 1 to 5). For the adjustment of the optical path length difference, a position where the luminance value is maximized in the depth direction of the tomographic image of the eye to be examined (position where the detection intensity of interference light is maximized) is used. As a position where such a luminance value is maximized, there is a position corresponding to a retinal pigment epithelium (RPE) of the eye to be examined.

JP 2007-185244 A JP 2007-215733 A Japanese Patent Laid-Open No. 2014-200678 JP 2014-200699 A JP 2014-200680 A

  By the way, in recent years, in an ophthalmologic apparatus using OCT, a parameter representing the structure of an eye to be examined, such as an axial length, is measured at once, or a wide range of the eye to be examined is imaged. It is required that OCT measurement is possible in a range.

  However, there is a trade-off relationship between the depth range of OCT measurement and the measurement accuracy, and when OCT measurement is performed over a wide range, it may be difficult to specify the retinal layer region such as the retinal pigment epithelium of the eye to be examined. . In such a case, before the OCT measurement, the difference between the optical path length of the reference light and the optical path length of the measurement light cannot be appropriately changed, and the target site is not depicted in the image of the eye to be examined. The parameter itself may not be measured.

  The present invention has been made in view of such circumstances, and its purpose is to image a target region of an eye to be examined at an appropriate position even when the depth range of OCT measurement is widened. An ophthalmologic apparatus capable of measuring and a control method thereof.

  The ophthalmologic apparatus according to the first aspect of the embodiment divides light from a light source into reference light and measurement light, irradiates the measurement eye with the measurement light, and returns light of the measurement light from the inspection 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. A luminance profile generation unit that generates a luminance profile in the optical axis direction of the interference optical system based on a detection result, and a control that controls the optical path length change unit based on a change in luminance value in the optical axis direction in the luminance profile Part.

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

  Moreover, the ophthalmologic apparatus according to the third aspect of the embodiment is the first aspect or the second aspect, wherein the specifying unit that specifies the position in the optical axis direction of the deepest region of the eye to be examined based on the change in the luminance value. In addition, the control unit may control the optical path length changing unit based on the position specified by the specifying unit.

  In the ophthalmologic apparatus according to the fourth aspect of the embodiment, in the third aspect, the specifying unit sets 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. You may specify.

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

  Moreover, the ophthalmologic apparatus which concerns on the 6th aspect of embodiment WHEREIN: The calculating part which calculates | requires the difference of two luminance values adjacent to the said optical axis direction in the said brightness profile in any one of a 1st aspect-a 5th aspect sequentially. In addition, the control unit may obtain the difference obtained by the calculation unit as a change in the luminance value, and may control the optical path length changing unit based on the obtained difference.

  Moreover, in the ophthalmologic apparatus which concerns on the 7th aspect of embodiment, the said optical path length change part is arrange | positioned in the optical path of the said reference light in any one of a 1st aspect-a 6th aspect, and follows the optical path of the said reference light. A movable reference mirror; and a moving mechanism that moves the reference mirror along an optical path of the reference light, and the control unit controls the moving mechanism to control the optical path length of the reference light and the measurement. The optical path length of light may be changed relatively.

  In the ophthalmologic apparatus according to the eighth aspect of the embodiment, in any one of the first aspect to the seventh aspect, the interference optical system repeatedly scans the eye to be examined with the measurement light, and the control unit The optical path length changing unit may be repeatedly controlled based on the change in the luminance value.

  The control method of the ophthalmologic apparatus according to the ninth aspect of the embodiment divides light from a light source into reference light and measurement light, irradiates the measurement light to the eye to be examined, and returns the measurement light from the eye to be examined. A detection step of detecting interference light between the light and the reference light, a luminance profile generation step of generating a luminance profile in the depth direction of the eye to be examined based on the detection result of the interference light, and the depth in the luminance profile 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 a change in luminance value in the vertical direction.

  Moreover, the control method of the ophthalmologic apparatus which concerns on the 10th aspect of embodiment contains the specific step which specifies the position of the said depth direction of the deepest area | region of the said to-be-tested eye based on the change of the said luminance value in a 9th aspect. In the optical path length difference changing step, based on the position in the depth direction, the optical path length of the reference light and the optical path length of the measurement light so that the deepest region is depicted within a predetermined range of an image frame. And may be changed relatively.

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

It is the schematic which shows an example of a structure of the optical system of the ophthalmologic apparatus which concerns on embodiment. It is the schematic which shows an example of a structure of the optical system of the ophthalmologic apparatus which concerns on embodiment. It is the schematic which shows an example of a structure of the control system of the ophthalmologic apparatus which concerns on embodiment. It is the schematic which shows an example of a structure of the control system of the ophthalmologic apparatus which concerns on embodiment. It is the schematic for demonstrating operation | movement of the ophthalmologic apparatus which concerns on embodiment. It is the schematic for demonstrating operation | movement of the ophthalmologic apparatus which concerns on embodiment. It is the schematic for demonstrating operation | movement of the ophthalmologic apparatus which concerns on embodiment. It is the schematic for demonstrating operation | movement of the ophthalmologic apparatus which concerns on embodiment. It is a flowchart which shows an example of operation | movement of the ophthalmologic apparatus which concerns on embodiment. It is a flowchart which shows an example of operation | movement of the ophthalmologic apparatus which concerns on embodiment.

  An example of an embodiment of an ophthalmologic apparatus according to the present invention will be described in detail with reference to the drawings. In addition, it is possible to use the description content of the literature referred in this specification, and arbitrary well-known techniques for the following embodiment.

  The ophthalmologic apparatus according to the embodiment is a measurement apparatus that has at least a function of executing OCT and can acquire information on the object to be measured by executing OCT on the object to be measured. Hereinafter, a case where the ophthalmologic 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 thereto. For example, the ophthalmologic apparatus according to the embodiment may be able to measure the intraocular distance of the living eye such as the axial length by executing 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. The ophthalmic apparatus has a function of executing the swept source OCT, but the embodiment is not limited thereto. For example, the type of OCT is not limited to the swept source OCT, and may be a spectral domain OCT or the like. Swept source OCT splits the light from a wavelength sweep type (wavelength scanning type) light source into measurement light and reference light, and generates interference light by interfering the return light of the measurement light passing through the object to be measured with the reference light. Then, this interference light is detected by a balanced photodiode or the like, and a Fourier transform or the like is performed on the detection data collected according to the wavelength sweep and the measurement light scan to form an image. Spectral domain OCT divides light from a low-coherence light source into measurement light and reference light, and generates interference light by causing the return light of the measurement light passing through the object to be measured to interfere with the reference light. In this method, a spectral distribution is detected by a spectroscope, and an image is formed by applying Fourier transform or the like to the detected spectral distribution.

  The ophthalmologic apparatus according to the embodiment is provided with a scanning laser ophthalmoscope (SLO), a slit lamp microscope, an anterior ocular photographing camera, a surgical microscope, a photocoagulator, and the like instead of the fundus camera. Also good. In this specification, OCT measurement is generically referred to as “OCT measurement”, images acquired by OCT are generically referred to as OCT images, 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”.

[Constitution]
As shown in FIG. 1, the ophthalmologic apparatus 1 according to the embodiment includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The retinal camera unit 2 has almost the same optical system as a conventional retinal 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 and control processes.

  In this specification, the “processor” is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or a programmable logic device (eg, SPLD (Simple ProLigL). It means a processing circuit including Programmable Logic Device (FPGA), Field Programmable Gate Array (FPGA), and the like. For example, the processor implements the functions according to the embodiment by reading and executing 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 obtaining a two-dimensional image (fundus image) representing the surface form of the fundus oculi Ef of the eye E to be examined. The fundus image includes an observation image and a captured image. 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 able to acquire images other than these, for example, a fluorescein fluorescent image, an indocyanine green fluorescent image, a spontaneous fluorescent image, and the like.

  The retinal camera unit 2 is provided with a chin rest and a forehead support for supporting the subject's face. 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 oculi Ef with illumination light. The photographing optical system 30 guides the fundus reflection light of the illumination light to an imaging device (CCD image sensor (sometimes simply referred to as a CCD) 35, 38). The imaging optical system 30 guides the measurement light from the OCT unit 100 to the eye E and guides the measurement light passing through the eye E to the OCT unit 100.

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

  The fundus reflection 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 center region of the perforated mirror 21, passes through the dichroic mirror 55, and is focused. The light is reflected by the mirror 32 via the lens 31. Further, the fundus reflection light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and forms an image on the light receiving surface of the CCD image sensor 35 by the condenser lens. The CCD image sensor 35 detects fundus reflected light at a predetermined frame rate, for example. On the display device 3, an image (observation image) based on fundus reflection light detected by the CCD image sensor 35 is displayed. When the photographing optical system 30 is focused on the anterior segment, an observation image of the anterior segment of the eye E is displayed.

  The imaging light source 15 is constituted by, for example, a xenon lamp or an LED. The light (imaging illumination light) output from the imaging light source 15 is applied to the fundus oculi Ef through the same path as the observation illumination light. The fundus reflection light of the imaging illumination light is guided to the dichroic mirror 33 through the same path as that of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is reflected by the condenser lens 37 of the CCD image sensor 38. An image is formed on the light receiving surface. On the display device 3, an image (captured image) based on fundus reflection light detected by the CCD image sensor 38 is displayed. Note that the display device 3 that displays the observation image and the display device 3 that displays the captured image may be the same or different. In addition, when similar imaging is performed by illuminating the eye E with infrared light, an infrared captured image is displayed. It is also possible to use an LED as a photographing light source.

  An LCD (Liquid Crystal Display) 39 displays a fixation target and an eyesight measurement target. The fixation target is a target for fixing the eye E to be examined, and is used at the time of fundus photographing or OCT measurement.

  A part of the light output from the LCD 39 is reflected by the half mirror 33 </ b> A, reflected by the mirror 32, passes through the hole of the perforated mirror 21 through the photographing focusing lens 31 and the dichroic mirror 55. 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 applied to the fundus oculi Ef. By changing the display position of the fixation target on the screen of the LCD 39, the fixation position of the eye E 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 a conventional fundus camera. The alignment optical system 50 generates a visual target (alignment visual target) for performing alignment (alignment) of the apparatus optical system with respect to the eye E. The focus optical system 60 generates a target (split target) for focusing on the eye E.

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

  The cornea-reflected light of the alignment light passes through the objective lens 22, the dichroic mirror 46, and the hole, part of which passes through the dichroic mirror 55 and passes through the photographing focusing lens 31. The cornea reflected light that has passed through the photographing focusing lens 31 is reflected by the mirror 32, passes through the half mirror 33 </ b> A, is reflected by the dichroic mirror 33, and is projected onto the light receiving surface of the CCD image sensor 35 by the condenser lens 34. A light reception image (alignment target) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The user performs alignment by performing the same operation as that of a conventional fundus camera. The arithmetic control unit 200 may perform alignment by analyzing the position of the alignment target and moving the optical system (auto-alignment function).

  The focus optical system 60 is movable along the optical path of the illumination optical system 10. The photographing focusing lens 31 is movable along the optical path of the photographing optical system 30 in conjunction with the movement of the focus optical system 60. The reflecting rod 67 of the focus optical system 60 can be inserted into and removed from the illumination optical path.

  When performing the focus adjustment, the reflection surface of the reflection bar 67 is obliquely provided on the illumination optical path. The light (focus light) output from the LED 61 of the focus optical system 60 passes through the relay lens 62, is separated into two light beams by the split target plate 63, and passes through the two-hole aperture 64. The light that has passed through the two-hole aperture 64 is reflected by the mirror 65, and once formed by the condenser lens 66 on the reflecting surface of the reflecting bar 67 and reflected. The light reflected by the reflecting surface of the reflecting rod 67 passes through the relay lens 20, is reflected by the aperture mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is received as a pair of split target light. The optometry E is irradiated.

  The pair of split target light beams that have passed through the pupil of the eye E reaches the fundus oculi Ef of the eye E. The fundus reflection 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 reflection light flux of the illumination light. A light reception image (a pair of split target images) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The arithmetic and control unit 200 analyzes the position of the pair of split target images and moves the focus optical system 60 to perform focusing as in the conventional case (autofocus function). The fundus image is formed on the imaging surface of the CCD image sensor 35 by moving the photographing focusing lens 31 in conjunction with the movement of the focus optical system 60. Further, focusing may be performed manually (by an operation on an operation unit 242 described later) while visually recognizing the pair of split target images.

  The reflector 67 is inserted at a position on the illumination optical path that is optically substantially conjugate with the fundus oculi Ef of the eye E to be examined. 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 that is optically substantially conjugate with the split target plate 63. As described above, the focus target light is separated into two by the action of the two-hole aperture 64 or the like. When the fundus oculi Ef and the reflection surface of the reflection bar 67 are not conjugate, the pair of split target images acquired by the CCD image sensor 35 are displayed on the display device 3 separately in two in the left-right direction, for example. . When the fundus oculi Ef and the reflecting surface of the reflecting bar 67 are substantially conjugate, the pair of split target images acquired by the CCD image sensor 35 is displayed on the display device 3 in the vertical direction, for example. When the focus optical system 60 is moved along the illumination optical path so that the fundus oculi Ef and the split target plate 63 are always optically conjugate, the photographing focusing lens 31 is linked along the photographing optical axis. Moving. When the fundus oculi Ef and the split target plate 63 are not conjugated, the pair of split target images are separated into two, and thus the focus optical system 60 so that the pair of split target images coincide with each other in the vertical direction. , The position of the photographing focusing lens 31 is obtained. In addition, although this embodiment demonstrated the case where a pair of split target image was acquired, three or more split target images may be sufficient.

  The dichroic mirror 46 branches the optical path for OCT from the optical path for fundus imaging. The dichroic mirror 46 reflects light in a wavelength band used for OCT and transmits light for fundus photographing. In this OCT optical path, 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 are provided in this order from the OCT unit 100 side. It has been.

  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 disposed at a position facing the emission end of the optical fiber. The collimator lens unit 40 converts the measurement light LS (described later) emitted from the emission end of the optical fiber into a parallel light beam and condenses the return light of the measurement light from the eye E on 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 or adjusting the interference state. The optical path length changing unit 41 includes, for example, a corner cube and a mechanism for moving the corner cube.

  For example, the optical scanner 42 is disposed at a position optically substantially conjugate with the pupil of the eye E. 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 can be scanned with the measurement light LS. The optical scanner 42 includes, for example, a galvanometer mirror that scans the measurement light LS in the x direction, a galvanometer mirror that scans in the y direction, and a mechanism that drives these independently. Thereby, the measurement light LS can be scanned in an arbitrary direction on the xy plane.

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

[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. This optical system divides the light from the wavelength sweep type (wavelength scanning type) light source into measurement light and reference light, and causes the return light of the measurement light from the eye E to interfere with the reference light via the reference light path. The interference optical system generates interference light and detects the interference light. The detection result (detection signal) of the interference light by the interference optical system is an interference signal indicating 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, as in a general swept source type ophthalmic apparatus. The swept wavelength light source includes a laser light source including a resonator. The light source unit 101 temporally changes the output wavelength in the near-infrared wavelength band that cannot be visually recognized by the human eye.

  The light L0 output from the light source unit 101 is guided to the polarization controller 103 by the optical fiber 102 and its polarization state is adjusted. The polarization controller 103 adjusts the polarization state of the light L0 guided through the optical fiber 102, for example, by 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 to the fiber coupler 105 by the optical fiber 104, and is divided into the measurement light LS and the reference light LR.

  The reference light LR is guided to the collimator 111 by the optical fiber 110 and becomes a parallel light beam. The reference light LR that has become a parallel light beam 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. By this movement, the length of the optical path of the reference light LR is changed. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye E or adjusting the interference state. The optical path length changing unit 114 includes, for example, a corner cube and a moving mechanism that moves the corner cube. In this case, the corner cube of the optical path length changing unit 114 turns the traveling direction of the reference light LR, which has been converted into a parallel light beam by the collimator 111, in the reverse direction. The optical path of the reference light LR incident on the corner cube is parallel to the optical path of the reference light LR emitted from the corner cube.

  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 (reference optical path, reference) of the reference light LR. Both of the optical path length changing units 114 for changing the length of the arm) are provided. However, only one of the optical path length changing units 41 and 114 may be provided. It is also possible to change the difference between the reference optical path length and the measurement optical path length using optical members other than these.

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

  An optical path length correction member may be disposed on 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 functions as a delay unit 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 to the polarization controller 118 and its polarization state is adjusted. For example, the polarization controller 118 has 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 light quantity is adjusted under the control of the arithmetic control unit 200. The reference light LR whose light amount has been 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 to the optical fiber 127 and converted into a parallel light beam by the collimator lens unit 40. The measurement light LS converted into a parallel light beam 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. The measurement light LS is scattered (including reflection) at various depth positions of the eye E. The return light of the measurement light LS including such backscattered light travels in the reverse direction on the same path as the forward path, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

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

  The detector 125 is, for example, a balanced photodiode that includes a pair of photodetectors that respectively detect a pair of interference lights LC and outputs a difference between detection results obtained by the pair of photodetectors. The detector 125 sends the detection result (interference signal) to a DAQ (Data Acquisition System) 130. The clock 130 is supplied from the light source unit 101 to the DAQ 130. The clock KC is generated in synchronization with the output timing of each wavelength swept (scanned) within a predetermined wavelength range by the wavelength sweep type light source in the light source unit 101. For example, 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 generates a clock KC based on the result of detecting these combined lights. Generate. The DAQ 130 samples the detection result of the detector 125 based on the clock KC. The DAQ 130 sends the sampled detection result of the detector 125 to the arithmetic control unit 200. The arithmetic control unit 200 performs a Fourier transform or the like on the spectrum distribution based on the detection result obtained by the detector 125 for each series of wavelength scans (for each A line), for example, thereby obtaining a reflection intensity profile in each A line. Form. Furthermore, 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 and forms an OCT image of the eye E. The arithmetic processing for forming an OCT image is the same as that of a conventional swept source type ophthalmic apparatus.

  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 and control unit 200 displays an OCT image of the eye E on the display device 3.

  The arithmetic control unit 200 includes, for example, a microprocessor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, and the like, as in a conventional computer. A computer program for controlling the ophthalmologic 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, a circuit board for forming an OCT image. 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 ophthalmologic apparatus 1 will be described with reference to FIGS. 3 and 4. In FIG. 3, some components of the ophthalmologic apparatus 1 are omitted, and components particularly necessary for explaining this embodiment are selectively shown.

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

  The lens driving unit 31 </ b> A receives the 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 that holds the photographing focusing lens 31, an actuator that generates a driving force for moving the holding member, and a transmission mechanism that transmits the driving force. The actuator is constituted by, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. As a result, the focus position of the photographic optical system 30 is changed by the lens driving unit 31 </ b> A receiving control from the main control unit 211 moving the photographic focusing lens 31. Note that the lens driving unit 31 </ b> A may move the photographing focusing lens 31 along the optical axis of the photographing optical system 30 by manual or user operation on the operation unit 242.

  Under the control of the main control unit 211, the lens driving unit 43A moves the OCT focusing lens 43 along the optical axis of the interference optical system (the optical path of the measurement light) in the OCT unit 100. The lens driving unit 43A includes a holding member that holds the OCT focusing lens 43, an actuator that generates a driving force for moving the holding member, and a transmission mechanism that transmits the driving force. The actuator is constituted by, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. As a result, the lens driving unit 43 </ b> A under the control of the main control unit 211 moves the OCT focusing lens 43, thereby changing the focus position of the measurement light. It should be noted that the lens driving unit 43A may move the OCT focusing lens 43 along the optical axis of the interference optical system by manual or user operation on the operation unit 242.

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

  The main control unit 211 can perform display control of the fixation target and the visual acuity measurement target for the LCD 39. Thereby, it is possible to switch the target presented to the eye E and change the type of the target. In addition, by changing the display position of the target on the LCD 39, the target display position for the eye E can be changed.

  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 by controlling the optical path length changing unit 41. The main control unit 211 controls the optical path length changing unit 41 so that the target site of the eye E is depicted 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 site of the eye E 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 on the fundus oculi Ef of the eye E by controlling the optical scanner 42.

  The optical system drive unit 1A moves the optical system (the optical system shown in FIGS. 1 and 2) provided in the ophthalmologic apparatus 1 three-dimensionally. The optical system driving unit 1A moves under the control of the main control unit 211 and moves the optical system. This control is used in alignment and tracking. Tracking refers to moving the apparatus optical system in accordance with the movement of the eye E. 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 apparatus optical system in real time according to the position and orientation of the eye E based on an image obtained by taking a moving image of the eye E. It is a function.

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

  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 by controlling the optical path length changing unit 114. The main control unit 211 controls the optical path length changing unit 114 so that the target site of the eye E is depicted 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 such that the target site of the eye E is depicted at a predetermined z position in the frame of the OCT image. 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 by controlling at least one of the optical path length changing units 41 and 114. In the following description, 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 only the optical path length changing unit 41 is controlled. Accordingly, the optical path length difference adjustment between the reference light LR and the measurement light LS may be performed.

  Such optical path length difference adjustment by the main control unit 211 is performed based on a luminance profile in the z direction generated from the detection result of the interference light obtained by 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 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. The luminance profile may be generated from the detection result by the detector 125. The main control unit 211 performs optical path length difference adjustment based on the change (change direction, change amount) of the luminance value in the z direction in the luminance profile. Specifically, the attention site of the eye E is identified based on the change in the luminance value in the z direction, and the optical path length difference adjustment is performed so that the identified region of interest is depicted at a predetermined z position in the frame. Is called. Examples of the attention site include the deepest region of the fundus oculi Ef (the deepest region of the image of the fundus oculi Ef, the region including the maximum z position where OCT measurement can be performed on the fundus oculi Ef).

  A tomographic image of the eye E 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. It is possible to maintain a state drawn at a predetermined z position.

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

(Memory part)
The storage unit 212 stores various data. Examples of the data stored in the storage unit 212 include image data of an OCT image, image data of a fundus image, and eye information to be examined. The eye information includes information about the subject such as patient ID and name, and information about the eye such as left / right eye identification information. The storage unit 212 stores various programs for operating the ophthalmologic apparatus 1 and data such as control information.

(Image forming part)
The image forming unit 220 forms tomographic image data of the fundus oculi Ef based on the interference signal from the detector 125 (DAQ 130). This processing 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 reflection intensity profiles in a plurality of A lines (paths of the measurement light LS in the eye E). is there.

  In order to improve the image quality, it is possible to superimpose (addition average) a plurality of data sets acquired 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 thereon may be identified. Moreover, the part of the eye E to be examined and the image thereof may be identified.

(Data processing part)
The data processing unit 230 performs various types of 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 luminance correction and dispersion correction.

  The data processing unit 230 can form volume data (voxel data) of the eye E by performing 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 a rendering process on the volume data to form a pseudo three-dimensional image when viewed from a specific viewing direction.

  The data processing unit 230 can perform alignment between 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 optical axis of the imaging optical system 30 is used to (substantially) simultaneously acquire the fundus image and the OCT image. Can be aligned with reference to. Regardless of the acquisition timing of the fundus image and the OCT image, the front image obtained by projecting at least a part of the image area corresponding to the fundus oculi Ef of the OCT image onto the xy plane is aligned with the fundus image. By doing so, it is possible to align the OCT image and the fundus image. This alignment method is applicable even when the fundus image acquisition optical system and the OCT optical system are not coaxial. Even if both optical systems are not coaxial, if the relative positional relationship between both optical systems is known, the same alignment as in the coaxial case is executed with reference to this relative positional relationship. It is possible.

  As shown in FIG. 4, the data processing unit 230 includes a luminance profile generation unit 231, a calculation unit 232, and a specification unit 233.

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

  For example, 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. In addition, the luminance profile generation unit 231, for example, with respect to the luminance values at a plurality of z positions in the B scan image generated based on the detection result by the detector 125, intersecting direction (for example, x direction or It is possible to generate a luminance profile by obtaining statistical values 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 and average values.

  Alternatively, the luminance profile generation unit 231 may generate a luminance profile in the z direction directly from the detection result of the interference light by the detector 125. For example, the luminance profile generation unit 231 analyzes the A-scan detection result obtained by the detector 125 to obtain reflected light intensity at a plurality of z positions, and assigns a luminance value corresponding to the obtained reflected light intensity. To generate a luminance profile. In addition, the luminance profile generation unit 231 analyzes the A-scan detection results obtained by the detector 125 for a plurality of scanning positions in the cross direction in the fundus oculi Ef, for example, and reflects light intensity at a plurality of z positions on each A line. The luminance profile may be generated by assigning a luminance value corresponding to the obtained reflected light intensity and obtaining a statistical value in the intersecting direction for the luminance values at a plurality of z positions.

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

  The calculation unit 232 obtains a change in the luminance value in the z direction in the luminance profile generated by the luminance profile generation unit 231. The computing unit 232 can determine the direction of change in luminance value in the z direction and the amount of change. For example, the calculation unit 232 obtains the change direction and the change amount of the luminance value in the z direction by sequentially obtaining the difference between two luminance values adjacent in the z direction in the acquired luminance 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 change amount thereof by obtaining the change rate of the luminance value corresponding to the change of the z position based on the acquired luminance profile. . The change direction corresponds to the sign of the obtained ratio. The amount of change corresponds to the absolute value of the obtained ratio.

  Hereinafter, the calculation unit 232 includes a difference calculation unit 2321. The difference calculation unit 2321 obtains a difference between two luminance values adjacent in the z direction in the luminance profile. That is, the calculation unit 232 obtains the change direction and the amount of change in the luminance value in the z direction by sequentially obtaining the difference between two luminance values adjacent in the z direction in the luminance profile.

  FIG. 5 is an explanatory diagram of a luminance profile according to the embodiment. FIG. 5 represents 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 acquires a plurality of z positions in a direction intersecting the depth direction (z direction) (the xy scan direction in FIG. 5). A luminance profile is generated by integrating the luminance values. As illustrated in FIG. 5, the luminance profile generation unit 231 obtains a luminance value La0 by integrating the luminance values of the respective pixels of the B-scan image IMG1 in the xy scan direction at the z position z0, and obtains the z position z1 (z0 <z1). The luminance values La1 are obtained by integrating the luminance values of the respective pixels of the B-scan image IMG1 in the xy scan direction, and the B-scan image IMG1 in the xy-scan direction at the z position zN (z1 <... <zN). The luminance values LaN are obtained by integrating the luminance values of the respective pixels.

  The calculation unit 232 generates a difference profile as illustrated in FIG. 5 by sequentially obtaining a difference between two luminance values adjacent in the z direction in the luminance profile generated by the luminance profile generation unit 231. In FIG. 5, the computing unit 232 obtains a 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) are obtained. A difference value D (N−1) (= LaN−La (N−1)) from the luminance value LaN corresponding to the position zN is obtained.

  The specifying unit 233 specifies the position in the z direction of the predetermined part of the eye E based on the difference profile representing the change in the luminance value in the z direction obtained by the calculation unit 232 as shown in FIG.

  FIG. 6 is an explanatory diagram of the difference profile according to the embodiment. FIG. 6 shows the difference value obtained by the calculation unit 232 on the vertical axis and the depth position on the horizontal axis. In FIG. 6, the difference values corresponding to the depth positions shown in FIG. In FIG. 6, for the 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 specifying 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 specifying unit 233 specifies a depth position corresponding to a difference value having a code corresponding to a predetermined change direction based on the difference profile obtained by the calculation unit 232. Subsequently, the specifying unit 233 specifies the depth position having the maximum absolute value among the difference values having the above sign as the position of the deepest region of the eye E.

  For example, in the case illustrated in FIGS. 5 and 6, a region with a sign “+” represents a region where a pixel having a high luminance value (black pixel) changes to a pixel having a low luminance value (white pixel). The region where “-” indicates that the region 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 the position included in the deepest region of the eye E.

  The specifying unit 233 can analyze the difference profile or the luminance profile in accordance with how the luminance value corresponding to the site of interest changes, and specify the z position of the site of interest. For example, the specifying unit 233 searches for 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 greater than the threshold with the sign “−”, as the shallowest region in the eye E to be examined. It can be specified as a position.

  The data processing unit 230 that functions as described above includes, for example, a microprocessor, a RAM, a ROM, a hard disk drive, a circuit board, and the like. In a storage device such as a hard disk drive, a computer program for causing the microprocessor to execute the above functions is stored 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 of the arithmetic control unit 200 and the display device 3 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 ophthalmologic apparatus 1 or outside. Further, the display unit 241 may include various display devices such as a touch panel provided in the housing of the fundus camera unit 2.

  The display unit 241 and the operation unit 242 do not need to be configured as individual devices. For example, a device in which a display function and an operation function are integrated, such as a touch panel, can be used. 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 electrical signal. Further, operations and information input may be performed using the graphical user interface (GUI) displayed on the display unit 241 and the operation unit 242.

  7 and 8 are diagrams for explaining the operation of the ophthalmologic apparatus 1 according to the embodiment. FIG. 7 shows an example of a tomographic image of the fundus oculi Ef drawn in the frame before adjusting the optical path length difference between the reference light LR and the measurement light LS. FIG. 8 illustrates an example of a tomographic image of the fundus oculi Ef depicted 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 examined (for example, the deep region of the fundus oculi Ef such as RPE) is depicted at the rendering position as shown in FIG. At this time, the luminance profile generation unit 231 generates a luminance profile as described above (FIG. 5). As described above, the calculation unit 232 generates a difference profile by sequentially obtaining a difference between two luminance values adjacent in the z direction in the luminance profile (FIG. 5). The specifying unit 233 specifies the position of the deepest region of the eye E as described above.

  The control unit 210 controls the optical path length changing unit 114 so that the deepest region of the eye E to be examined specified by the specifying unit 233 is drawn at a predetermined z position in the frame, thereby controlling 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 an optical path length difference adjustment amount between the reference light LR and the measurement length LS is associated with each of the z positions of the deepest regions with respect to a predetermined reference z position. Examples of the predetermined reference z position include 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 specified by the specifying unit 233, the control unit 210 refers to the control information stored in the storage unit 212, and determines the optical path length adjustment amount associated with the z position. The optical path length changing unit 114 is controlled based on the determined optical path length adjustment amount. Thereby, as shown in FIG. 8, a tomographic image in which the deepest area of the eye E is depicted at a predetermined z position in the frame is acquired.

  The storage unit 212 may store in advance control information in which the control content for the optical path length changing unit 114 is associated with each z position of the plurality of deepest regions with respect to a 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 examined specified by the specifying unit 233, the control unit 210 refers to the control information stored in the storage unit 212 and controls 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 illustrated 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]
An operation of the ophthalmologic apparatus 1 according to the embodiment will be described. In the following, it is assumed that the region of interest of the eye E is the deepest region in the tomographic image of the fundus oculi Ef.

  FIG. 9 shows an example of the operation of the ophthalmologic apparatus 1 according to the embodiment. FIG. 9 is a flowchart of an operation example when acquiring an OCT image and a fundus image of the eye E.

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

(S2)
The main control unit 211 controls the optical system driving unit 1A based on the anterior segment image acquired in S1 to move the optical system in a three-dimensional manner, and the position of the optical system with respect to the eye E to be examined. Matching is performed (x direction, y direction, and z direction orthogonal to both the x direction and the y direction).

(S3)
The main controller 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 oculi Ef of the eye E 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 oculi Ef based on the detection result of the interference light by the detector 125.

(S5)
The main control unit 211 performs alignment of the retina focus direction from the anterior segment image obtained by the imaging optical system 30. Thereby, the position of the optical system provided in the OCT unit 100 in the optical axis direction can be finely adjusted.

(S6)
The main control unit 211 starts adjustment of the drawing position in the frame of the target region of the eye E to be examined. From S6 onward, a tomographic image of the eye E is repeatedly acquired, a luminance profile is generated from the acquired tomographic image, and optical path length difference adjustment is repeatedly performed based on the generated luminance profile. Thereby, the state in which the target region of the eye E is depicted at the 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 provided 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 driving unit 43A so as to maximize the amplitude of the detection signal of the predetermined interference light, and moves the OCT focusing lens 43 in the optical axis direction, thereby moving the focal position of the optical system. To change.

(S8)
The main controller 211 again controls the optical scanner 42 to start scanning the fundus oculi Ef of the eye E 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 oculi 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 is depicted 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 oculi Ef of the eye E to be examined. Thus, the operation of the ophthalmologic apparatus 1 ends (END).

  FIG. 10 shows a flowchart of the operation example of S6 of FIG.

(S21)
In S6 of FIG. 9, when the adjustment of the rendering position within the frame of the target region of the eye E is started, the main control unit 211 causes the luminance profile generation unit 231 to generate a luminance profile as shown in FIG. The luminance 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 S4 or the repetitive scanning of the measurement light LS. The luminance profile generation unit 231 generates a luminance profile by integrating 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 a difference between two luminance values adjacent in the z direction in the luminance profile generated in S21. .

(S23)
The main control unit 211 causes the specifying unit 233 to specify the z position of the deepest region of the eye E as described above. Based on the difference profile generated in S22, the specifying unit 233 specifies, for example, the depth position having the maximum absolute value among the difference values having the sign “+” as the z position of the deepest region of the eye E (specific). 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 of the deepest region of the eye E specified in S23, and 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 adjustment amount determined in S24 and refers so that the deepest region of the eye E is depicted at a predetermined z position in the frame. The optical path length difference between the light LR and the measuring light LS is changed (optical path length difference changing step). For example, it is possible to repeatedly scan the fundus oculi Ef of the eye E with the measurement light LS, and execute S21 to S25 when the tomographic image is acquired to repeatedly adjust the optical path length difference.

[effect]
An ophthalmologic apparatus according to an embodiment will be described.

  The ophthalmologic 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 luminance profile generating unit (231). And a control unit (210, main control unit 211). The interference optical system divides light (L0) from the light source (light source unit 101) into reference light (LR) and measurement light (LS), irradiates the measurement eye with the measurement light (E), 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 luminance profile generation unit generates a luminance 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 a change in luminance value (change direction, change amount) in the optical axis direction in the luminance profile.

  In such a configuration, the interference optical system generates a luminance 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 detected, and the generated luminance profile The optical path length difference between the reference light and the measurement light is changed based on the change in the luminance value in the optical axis direction. Thereby, there is no need to specify a region or the like having the maximum luminance value in the OCT image, and the drawing position and the measurable position of the target region of the eye to be examined can be changed. Therefore, it is possible to provide an ophthalmologic apparatus capable of changing the rendering position and the measurable position with respect to the target region of the eye to be examined even when the measurement accuracy is lowered by widening the depth range of OCT measurement. become. As a result, even when the depth range of OCT measurement is widened, an ophthalmologic apparatus capable of imaging and measuring the attention site of the eye to be examined at an appropriate position can be provided. For example, even when OCT measurement is performed in a so-called full range, it is possible to image or measure the attention site of the eye to be examined at an appropriate position.

  The ophthalmologic 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 examined based on the detection result of the interference light by the interference optical system. The interference optical system may include an optical scanner (42). The optical scanner deflects measurement light in a scan direction (xy scan direction) that intersects the optical axis direction. The luminance profile generation unit can generate a luminance profile by accumulating luminance values in the scan 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 luminance profile is generated from the tomographic image formed by the image forming unit, the rendering position and the measurable position can be easily changed with respect to the target region of the eye to be examined. An ophthalmic apparatus can be provided.

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

  According to such a configuration, since the position in the optical axis direction of the deepest region of the eye to be examined is specified based on the change of the luminance value in the luminance profile, the measurement accuracy can be increased by widening the depth range of the OCT measurement. An ophthalmologic apparatus capable of changing the rendering position and the measurable position with respect to the deepest region of the eye to be examined can be provided even when the eye drops.

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

  According to such a configuration, the position where the absolute value of the change amount is maximum in the predetermined change direction in the luminance profile is specified, so that it is possible to specify the deepest region of the eye to be examined with a simple process. Become. As a result, an ophthalmologic apparatus that can change the rendering position and the measurable position with respect to the deepest region of the eye to be examined with a simple process even when the depth range of OCT measurement is widened and the measurement accuracy is lowered is provided. Will be able to.

  In the ophthalmologic apparatus according to the embodiment, the control unit may control the optical path length changing unit so that the deepest region is depicted within a predetermined range of the image frame.

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

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

  According to such a configuration, since the change of the luminance value is specified by simply calculating the difference value, even when the depth range of the OCT measurement is widened and the measurement accuracy is lowered, the processing is performed with a simple process. It is possible to provide an ophthalmologic apparatus capable of changing the drawing position and the measurable position with respect to the attention site of the optometry.

  In the ophthalmologic 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 disposed in the optical path of the reference light and is movable 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, since the reference optical path length is changed with a simple configuration and control, even when the depth range of the OCT measurement is widened and the measurement accuracy is lowered, the target region of the eye to be examined is reduced. Thus, it is possible to simplify the configuration and control of the ophthalmologic apparatus capable of changing the rendering position and the measurable position.

  In the ophthalmic apparatus according to the embodiment, the interference optical system repeatedly scans the eye to be examined with the measurement light, and the control unit repeatedly controls the optical path length changing unit based on the change in the luminance value. May be.

  According to such a configuration, it is possible to provide an ophthalmologic apparatus capable of maintaining the state in which the target region of the eye to be examined is depicted at a desired depth position.

  The control method of the ophthalmologic apparatus (ophthalmologic apparatus 1) according to the embodiment includes a detecting step, a luminance profile generating 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 reference light (LR) and measurement light (LS), and the measurement light is irradiated to the eye to be examined (E), and measurement from the eye to be examined is performed. Interference light (LC) between light return light and reference light is detected. In the luminance profile generation step, a luminance profile in the depth direction (z direction) of the eye to be examined 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, change amount) of the brightness value in the depth direction in the brightness profile.

  In such a configuration, the interference optical system detects interference light between the reference light and the measurement light passing through the eye to be examined, generates a luminance profile in the optical axis direction of the interference optical system based on the detection result, and generates The optical path length difference between the measurement light and the reference light is changed based on the change in the luminance value in the optical axis direction in the luminance profile thus obtained. Thereby, the rendering position and the measurable position of the target region of the eye to be examined can be changed without specifying the region or the like having the maximum luminance value in the OCT image. Therefore, it is possible to provide an ophthalmologic apparatus capable of changing the rendering position and the measurable position with respect to the target region of the eye to be examined even when the measurement accuracy is lowered by widening the depth range of OCT measurement. become. As a result, even when the depth range of OCT measurement is widened, it is possible to image and measure the attention site of the eye to be examined at an appropriate position.

  Moreover, the control method of the ophthalmologic apparatus according to the embodiment may include a specific step. In the specifying step, the position in the depth direction of the deepest region of the eye to be examined is specified based on the change in luminance value. In the optical path length difference changing step, based on the position in the depth direction, 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 depicted within a predetermined range of the image frame. can do.

  According to such a configuration, the depth position of the deepest region of the eye to be examined is specified based on the change in the luminance value in the luminance profile, and the deepest within the predetermined range of the image frame 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 relatively changed so that the region is depicted, even if the measurement accuracy is lowered by widening the depth range of the OCT measurement, 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 in the frame.

<Modification>
The embodiment described above is merely an example for carrying out the present invention. A person who intends to implement the present invention can make arbitrary modifications, omissions, additions and the like within the scope of the present invention.

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

DESCRIPTION OF SYMBOLS 1 Ophthalmology apparatus 2 Fundus camera unit 41, 114 Optical path length change part 42 Optical scanner 100 OCT unit 200 Arithmetic control unit 210 Control part 211 Main control part 212 Storage part 220 Image formation part 230 Data processing part 231 Luminance profile generation part 232 Operation part 233 Identification unit 2311 Integration unit 2321 Difference calculation unit E Eye Ef fundus LC Interference light LR Reference light LS Measurement light

Claims (10)

An interference optical system that divides light from a light source into reference light and measurement light, irradiates the measurement light on the eye to be examined, and detects interference light between the return light of the measurement light from the eye to be examined 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 a 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 luminance value in the optical axis direction in the luminance profile;
Ophthalmic device. An image forming unit that forms a tomographic image of the eye to be examined based on a detection result of the interference light by the interference optical system;
The interference optical system includes an optical scanner that deflects the measurement light in a scan direction that intersects the optical axis direction;
The ophthalmologic according to claim 1, wherein the luminance profile generation unit generates the luminance profile by integrating luminance values in the scan direction for each of a plurality of positions in the optical axis direction in the tomographic image. apparatus. A specifying unit that specifies the position of the deepest region of the eye to be examined in the optical axis direction based on the change in the luminance value;
The ophthalmologic apparatus according to claim 1, wherein the control unit controls the optical path length changing unit based on the position specified by the specifying unit. The ophthalmic apparatus according to claim 3, wherein the specifying unit specifies a position where the absolute value of the change amount of the luminance value in a predetermined change direction is the maximum as the position of the deepest region. The ophthalmologic apparatus according to claim 3 or 4, wherein the control unit controls the optical path length changing unit so that the deepest region is depicted within a predetermined range of a frame of an image. A calculation unit for sequentially obtaining a difference between two luminance values adjacent in the optical axis direction in the luminance profile;
The said control part calculates | requires the difference calculated | required by the said calculating part as a change of the said luminance value, and controls the said optical path length change part based on the calculated | required said difference. The ophthalmic apparatus according to any one of the above. The optical path length changing unit is
A reference mirror disposed in the optical path of the reference light and movable along the optical path of the reference light;
A moving mechanism for moving the reference mirror along the optical path of the reference light;
Including
The said control part changes the optical path length of the said reference light, and the optical path length of the said measurement light relatively by controlling the said moving mechanism. The claim 1 characterized by the above-mentioned. An ophthalmic device according to claim 1. The interference optical system repeatedly scans the eye to be examined with the measurement light,
The ophthalmic apparatus according to any one of claims 1 to 7, wherein the control unit repeatedly controls the optical path length changing unit based on a change in the luminance value. A detection step of dividing light from a light source into reference light and measurement light, irradiating the eye to be examined with the measurement light, and detecting interference light between the return light of the measurement light from the eye to be examined and the reference light; ,
A luminance profile generating step for generating a luminance profile in the depth direction of the eye to be examined based on the detection result of the interference light;
An optical path length difference changing step for relatively changing the optical path length of the reference light and the optical path length of the measurement light based on a change in the brightness value in the depth direction in the brightness profile;
A method for controlling an ophthalmic apparatus. A specifying step of specifying a position in the depth direction of the deepest region of the eye to be examined based on the change in the luminance value;
In the optical path length difference changing step, based on the position in the depth direction, an optical path length of the reference light and an optical path length of the measurement light so that the deepest region is depicted within a predetermined range of an image frame. The method for controlling an ophthalmic apparatus according to claim 9, wherein:

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