JP7374272B2 - ophthalmology equipment - Google Patents

Description

TECHNICAL FIELD This invention relates to an ophthalmological device.

In recent years, optical coherence tomography (OCT), which uses light interference to image the surface and internal forms of objects, has been attracting attention. Since OCT is not invasive to the human body like X-ray CT, it is expected to be used particularly in the medical and biological fields. For example, in the field of ophthalmology, devices that image the fundus of the eye and the cornea have been put into practical use.

In an ophthalmological apparatus using OCT, the difference between the optical path length of the measurement light and the optical path length of the reference light is adjusted so that the target region of the eye to be examined is depicted at a suitable position in the imaging range by OCT measurement.

For example, Patent Document 1 discloses an ophthalmologic apparatus that executes automatic processing (auto Z) to search for a suitable optical path length difference so that a region of interest is depicted in an imaging range by OCT measurement. In this ophthalmological device, by executing automatic processing (Z lock) to maintain a suitable depiction position obtained by auto-Z, the region of interest is depicted at a predetermined z position (depth position) in the imaging range. The optical path length difference is controlled so that this state is maintained.

Japanese Patent Application Publication No. 2016-041221

However, in the prior art, the z position maintained by the z lock is fixed. As a result, when the measurement range by OCT measurement becomes wider in the x-y direction or deeper in the z-direction, the region of interest may be depicted at the edge of the imaging range or out of the imaging range, depending on the curvature state of the eyeball.

In particular, when OCT measurement is performed over a wide range for a highly myopic eye, the image may be interrupted at the upper or lower end of the imaging range, or the display may be folded back. Therefore, it is necessary for the examiner to keep watching the OCT measurement, which increases the burden on the examiner who performs the OCT measurement. Alternatively, it is necessary to check the measurement results and perform re-measurement as necessary, which increases the burden on the subject undergoing OCT measurement.

The present invention has been made in view of these circumstances, and its purpose is to provide a new technique for reducing the burden on examiners or subjects when performing OCT measurements.

One aspect of the embodiment is that the optical path length difference between the measurement optical path and the reference optical path can be changed, the light from the light source is divided into the measurement light and the reference light, and the measurement light that has passed through the measurement optical path is divided into the measurement light and the reference light. an interference optical system that irradiates the eye to be examined and detects interference light between return light from the eye to be examined and the reference light that has passed through the reference optical path; identifying a first reference position in the depth direction of a first B-scan for the eye to be examined based on an image forming unit to form and a retinal pigment epithelial layer in the image formed by the image forming unit; an analysis unit that specifies a second reference position in the depth direction of a second B scan for the eye to be examined according to the refractive power of the eye to be examined based on the first reference position; When performing a plurality of B-scans including the first B-scan and the second B-scan, the interference is performed such that an image based on the detection result of the interference light is placed at the first reference position. The first B-scan is performed on the scan range of the eye to be examined by controlling the optical system to change the optical path length difference, and the image is placed at the second reference position. The ophthalmologic apparatus includes a control unit that controls an interference optical system to change the optical path length difference to execute the second B-scan in the scan range of the eye to be examined .

According to the present invention, it is possible to reduce the burden on the examiner or subject when performing OCT measurement.

FIG. 1 is a schematic diagram showing an example of the configuration of an ophthalmologic apparatus according to an embodiment. FIG. 1 is a schematic diagram showing an example of the configuration of an ophthalmologic apparatus according to an embodiment. FIG. 1 is a schematic block diagram showing an example of the configuration of an ophthalmologic apparatus according to an embodiment. FIG. 1 is a schematic block diagram showing an example of the configuration of an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining processing performed by an ophthalmologic apparatus according to an embodiment. It is a flow chart showing an example of operation of an ophthalmologic device concerning an 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. Note that the contents of the documents cited in this specification and any known technology can be incorporated into the following embodiments.

The ophthalmological apparatus according to the embodiment can form a tomographic image, a frontal image, and a three-dimensional image of the eye to be examined using OCT. In this specification, images acquired by OCT may be collectively referred to as OCT images. Furthermore, a measurement operation for forming an OCT image is sometimes referred to as OCT measurement.

The ophthalmologic apparatus according to some embodiments includes any one or more of an ophthalmologic imaging device, an ophthalmologic measurement device, and an ophthalmologic treatment device. The ophthalmologic imaging device included in the ophthalmologic apparatus of some embodiments is, for example, one or more of a fundus camera, a scanning laser ophthalmoscope, a slit lamp ophthalmoscope, a surgical microscope, and the like. In addition, the ophthalmological measuring device included in the ophthalmological apparatus of some embodiments is, for example, any one or more of an eye refraction test device, a tonometer, a specular microscope, a wavefront analyzer, a perimeter, a microperimeter, etc. It is. Further, the ophthalmologic treatment device included in the ophthalmologic device of some embodiments is, for example, one or more of a laser treatment device, a surgical device, a surgical microscope, and the like.

The ophthalmological apparatus according to the following embodiments includes an OCT apparatus capable of OCT measurement and a fundus camera. Although swept source OCT is applied to this OCT apparatus, the type of OCT is not limited to this, and other types of OCT (spectral domain OCT, time domain OCT, unfavorable OCT, etc.) may be applied. Further, it is also possible to incorporate the configuration according to the following embodiments into a single OCT apparatus.

In the following, a case in which an image of the fundus of the eye is acquired will be described in detail, but the part of the eye to be photographed is not limited to the fundus of the eye. For example, the configuration according to this embodiment can be applied to an apparatus for performing OCT measurement of the anterior segment of the eye, such as the cornea. Furthermore, it is also possible to apply the configuration of this embodiment to an apparatus capable of OCT measurement of both the fundus and the anterior segment of the eye. As an example of this case, it is possible to employ a configuration in which an attachment (an objective lens, a front lens, etc.) for photographing the anterior segment is added to a device for photographing the fundus described below.

<Configuration>
〔Optical system〕
As shown in FIG. 1, the ophthalmologic apparatus 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The fundus camera unit 2 is provided with an optical system and a mechanism for acquiring a frontal image of the eye E to be examined. The OCT unit 100 is provided with an optical system and part of a mechanism for performing OCT. Other parts of the optical system and mechanism for performing OCT are provided in the fundus camera unit 2. Arithmetic control unit 200 includes one or more processors that perform various calculations and controls. In addition to these, optional elements such as members for supporting the subject's face (chin rest, forehead rest, etc.) and lens units for switching the target area of OCT (for example, attachment for anterior segment OCT) or a unit may be provided in the ophthalmological apparatus 1.

In this specification, "processor" refers to, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (e.g. , SPLD (Simple Programmable Logic Device), CPLD (Complex It means a circuit such as a programmable logic device (programmable logic device) or FPGA (field programmable gate array). The processor realizes the functions according to the embodiment by, for example, 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 photographing the fundus Ef of the eye E to be examined. The acquired image of the fundus Ef (referred to as a fundus image, fundus photograph, etc.) is a frontal image such as an observation image or a photographed image. Observation images are obtained by video shooting using near-infrared light. The photographed image is a still image using flash light. Furthermore, the fundus camera unit 2 can photograph the anterior segment Ea of the eye E to be examined to obtain a frontal image (anterior segment image).

The fundus camera unit 2 includes an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the eye E to be examined with illumination light. The photographing optical system 30 detects the return light of the illumination light from the eye E to be examined. The measurement light from the OCT unit 100 is guided to the eye E through the optical path within the fundus camera unit 2, and the return light is guided to the OCT unit 100 through the same optical path.

The light (observation illumination light) output from the observation light source 11 of the illumination optical system 10 is reflected by the reflection mirror 12 having a curved reflection surface, passes through the condensing lens 13, and passes through the visible cut filter 14. It becomes near-infrared light. Further, the observation illumination light is once converged near the photographing light source 15, reflected by a mirror 16, and passes through relay lenses 17, 18, an aperture 19, and a relay lens 20. The observation illumination light is reflected at the periphery of the apertured mirror 21 (the area around the aperture), passes through the dichroic mirror 46, is refracted by the objective lens 22, and is refracted by the objective lens 22. Part Ea) is illuminated. The return light of the observation illumination light from the subject's eye E 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, and passes through the dichroic mirror 55. . The returning light that has passed through the dichroic mirror 55 passes through the photographic focusing lens 31 and is reflected by the mirror 32. Further, this returned light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged by the condenser lens 34 on the light receiving surface of the image sensor 35. The image sensor 35 detects the returned light at a predetermined frame rate. Note that the focus of the photographing optical system 30 is adjusted to match the fundus Ef or the anterior segment Ea.

The light output from the photographing light source 15 (photographing illumination light) passes through the same path as the observation illumination light and is irradiated onto the fundus Ef. The return light of the imaging illumination light from the eye E is guided to the dichroic mirror 33 through the same path as the return light 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. An image is formed on the light receiving surface of the image sensor 38.

An LCD (Liquid Crystal Display) 39 displays a fixation target and a visual acuity measurement target. A portion of the light beam output from the LCD 39 is reflected by the half mirror 33A, then reflected by the mirror 32, passes through the photographic focusing lens 31 and the dichroic mirror 55, and then passes through the hole of the perforated mirror 21. The light beam that has passed through the hole of the perforated mirror 21 is transmitted through the dichroic mirror 46, refracted by the objective lens 22, and projected onto 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 examined can be changed. Examples of fixation positions include a fixation position for acquiring an image centered on the macula, a fixation position for acquiring an image centered on the optic disc, and a fixation position for acquiring an image centered on the optic disc, and the center of the fundus between the macula and optic disc. There is a fixation position for acquiring an image centered on the macula, and a fixation position for acquiring an image of a region far away from the macula (periphery of the fundus). The ophthalmological apparatus 1 according to some embodiments includes a GUI (Graphical User Interface) and the like for specifying at least one of such fixation positions. The ophthalmologic apparatus 1 according to some embodiments includes a GUI, etc. for manually moving the fixation position (the display position of the fixation target).

The configuration for presenting a movable fixation target to the eye E to be examined is not limited to a display device such as an LCD. For example, a movable fixation target can be generated by selectively lighting up a plurality of light sources in a light source array (such as a light emitting diode (LED) array). Furthermore, a movable fixation target can be generated using one or more movable light sources.

Additionally, the ophthalmological device 1 may be provided with one or more external fixation light sources. One of the one or more external fixation light sources is capable of projecting fixation light onto the companion eye of the eye E to be examined. The projection position of the fixation light on the companion eye can be changed. By changing the projection position of the fixation light to the companion eye, the fixation position of the eye E to be examined can be changed. The fixation position by the external fixation light source may be the same as the fixation position of the eye E using the LCD 39. For example, a movable fixation target can be generated by selectively lighting up a plurality of external fixation light sources. Furthermore, a movable fixation target can be generated by one or more movable external fixation light sources.

The alignment optical system 50 generates an alignment index used for alignment of the optical system with respect to the eye E to be examined. The alignment light output from the LED 51 passes through the apertures 52 and 53 and the relay lens 54, is reflected by the dichroic mirror 55, and passes through the hole of the perforated mirror 21. The light that has passed through the hole of the perforated mirror 21 is transmitted through the dichroic mirror 46 and is projected onto the eye E by the objective lens 22. The corneal reflected light of the alignment light is guided to the image sensor 35 through the same path as the return light of the observation illumination light. Manual alignment or auto alignment can be performed based on the received light image (alignment index image).

The focus optical system 60 generates a split index used for focus adjustment for the eye E to be examined. The focus optical system 60 is moved along the optical path of the illumination optical system 10 (illumination optical path) in conjunction with the movement of the photographic focusing lens 31 along the optical path of the photographic optical system 30 (photographic optical path). The reflection rod 67 can be inserted into and removed from the illumination optical path. When performing focus adjustment, the reflective surface of the reflective rod 67 is arranged at an angle to the illumination optical path. The focus light output from the LED 61 passes through a relay lens 62 , is separated into two beams by a split indicator plate 63 , passes through a two-hole diaphragm 64 , is reflected by a mirror 65 , and is reflected by a condensing lens 66 into a reflecting rod 67 . Once the image is formed on the reflective surface of the image, it is reflected. Further, the focus light passes through the relay lens 20, is reflected by the apertured mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef. The fundus reflected light of the focus light is guided to the image sensor 35 through the same path as the corneal reflected light of the alignment light. Manual focus or autofocus can be performed based on the received light image (split index image).

The dichroic mirror 46 combines the fundus imaging optical path and the OCT optical path. The dichroic mirror 46 reflects light in a wavelength band used for OCT and transmits light for fundus photography. The OCT optical path (the optical path of measurement light) includes, in order from the OCT unit 100 side to the dichroic mirror 46 side, a collimator lens unit 40, an optical path length changing section 41, an optical scanner 42, an OCT focusing lens 43, a mirror 44, and a relay lens 45 are provided.

The optical path length changing unit 41 is movable in the direction of the arrow shown in FIG. 1, and changes the length of the OCT optical path. This change in optical path length is used to correct the optical path length according to the axial length of the eye, adjust interference conditions, and the like. The optical path length changing unit 41 includes a corner cube and a mechanism for moving the corner cube.

The optical scanner 42 is arranged at a position optically conjugate with the pupil of the eye E to be examined. The optical scanner 42 deflects the measurement light LS passing through the OCT optical path. The optical scanner 42 is, for example, a galvano scanner capable of two-dimensional scanning.

The OCT focusing lens 43 is moved along the optical path of the measurement light LS in order to perform focus adjustment of the optical system for OCT. Movement of the imaging focusing lens 31, movement of the focusing optical system 60, and movement of the OCT focusing lens 43 can be controlled in a coordinated manner.

[OCT unit]
As illustrated in FIG. 2, the OCT unit 100 is provided with an optical system for performing swept source OCT. This optical system includes an interference optical system. This interference optical system has the function of splitting the light from the wavelength variable light source (wavelength swept type light source) into the measurement light and the reference light, and the return light of the measurement light from the eye E and the reference light via the reference optical path. It has a function of superimposing the two to generate interference light, and a function of detecting this interference light. The detection result (detection signal) of the interference light obtained by the interference optical system is a signal indicating the spectrum of the interference light, and is sent to the arithmetic and control unit 200.

The light source unit 101 includes, for example, a near-infrared variable wavelength laser that changes the wavelength of emitted light at high speed. Light L0 output from the light source unit 101 is guided to a polarization controller 103 by an optical fiber 102, and its polarization state is adjusted. The light L0 whose polarization state has been adjusted is guided to a fiber coupler 105 by an optical fiber 104 and is split into a measurement light LS and a reference light LR.

The reference light LR is guided to a collimator 111 by an optical fiber 110, converted into a parallel light beam, and guided to a corner cube 114 via an optical path length correction member 112 and a dispersion compensation member 113. The optical path length correction member 112 acts to match the optical path length of the reference light LR and the optical path length of the measurement light LS. The dispersion compensation member 113 acts to match the dispersion characteristics between the reference light LR and the measurement light LS. The corner cube 114 is movable in the direction of incidence of the reference light LR, thereby changing the optical path length of the reference light LR.

The reference light LR that has passed through the corner cube 114 passes through the dispersion compensating member 113 and the optical path length correcting member 112, is converted from a parallel beam into a convergent beam by the collimator 116, and enters the optical fiber 117. The reference light LR incident on the optical fiber 117 is guided to a polarization controller 118 to have its polarization state adjusted, guided to an attenuator 120 by an optical fiber 119 to have its light amount adjusted, and then guided to a fiber coupler 122 by an optical fiber 121. It will be destroyed.

On the other hand, the measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and converted into a parallel light beam by the collimator lens unit 40. and relay lens 45 . The measurement light LS passing through the relay lens 45 is reflected by the dichroic mirror 46, refracted by the objective lens 22, and enters the eye E to be examined. The measurement light LS is scattered and reflected at various depth positions of the eye E to be examined. The return light of the measurement light LS from the eye E to be examined travels in the same direction as the outgoing 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 with) 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 generates a pair of interference lights LC by branching the interference lights at a predetermined branching ratio (for example, 1:1). A pair of interference lights LC are guided to a detector 125 through optical fibers 123 and 124, respectively.

Detector 125 is, for example, a balanced photodiode. The balanced photodiode includes a pair of photodetectors that respectively detect a pair of interference lights LC, and outputs a difference between a pair of detection results obtained by these photodetectors. The detector 125 sends this output (detection signal) to a DAQ (Data Acquisition System) 130.

The DAQ 130 is supplied with a clock KC 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 within a predetermined wavelength range by the variable wavelength light source. 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 outputs the clock KC based on the result of detecting these combined lights. generate. The DAQ 130 samples the detection signal input from the detector 125 based on the clock KC. The DAQ 130 sends the sampling result of the detection signal from the detector 125 to the arithmetic control unit 200.

In this example, an optical path length changing unit 41 is used to change the length of the optical path (measurement optical path, measurement arm) of the measurement light LS, and an optical path length changing unit 41 is used to change the length of the optical path (reference optical path, reference arm) of the reference light LR. Both corner cubes 114 are provided. However, only one of the optical path length changing section 41 and the corner cube 114 may be provided. It is also possible to change the difference between the measurement optical path length and the reference optical path length using optical members other than these.

[Calculation control unit]
The arithmetic control unit 200 analyzes the detection signal input from the DAQ 130 and forms an OCT image of the fundus Ef. The arithmetic processing for this purpose is similar to that of a conventional swept source type OCT device.

Further, the arithmetic control unit 200 controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100.

In order to control the fundus camera unit 2, the arithmetic control unit 200 controls the operation of the observation light source 11, the photographing light source 15, and the LEDs 51 and 61, controls the operation of the LCD 39, controls the movement of the photographic focusing lens 31, and controls the OCT focusing lens 43. It performs movement control, movement control of the reflection rod 67, movement control of the focus optical system 60, movement control of the optical path length changing section 41, operation control of the optical scanner 42, and the like.

To control the OCT unit 100, the arithmetic control unit 200 controls the operation of the light source unit 101, the polarization controllers 103 and 118, the attenuator 120, the detector 125, the DAQ 130, etc. .

The arithmetic control unit 200 is configured to include, for example, a microprocessor, RAM, ROM, hard disk drive, communication interface, etc., like 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. 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.

The fundus camera unit 2, display device 3, OCT unit 100, and arithmetic control unit 200 may be configured integrally (that is, in a single housing), or may be configured separately in two or more housings. may have been done.

[Control system]
3 and 4 show examples of the configuration of the control system of the ophthalmologic apparatus 1. In FIGS. 3 and 4, some of the components included in the ophthalmologic apparatus 1 are omitted. The control section 210, the image forming section 220, and the data processing section 230 are provided in the arithmetic control unit 200, for example.

(control unit)
The control unit 210 executes various controls. Control section 210 includes a main control section 211 and a storage section 212.

(Main control part)
The main control unit 211 includes a processor and controls each part of the ophthalmologic apparatus 1 . For example, the main control unit 211 controls the optical path length changing unit 41 of the fundus camera unit 2, the optical scanner 42, the imaging focusing lens 31 (focusing drive unit 31A), the focusing optical system 60, the OCT focusing lens 43 (focusing The driving unit 43A), the image sensors 35, 38, the LCD 39, the entire optical system (the moving mechanism 150), and the like are controlled. Furthermore, the main control section 211 controls the light source unit 101, corner cube 114 (reference drive section 114A), attenuator 120, polarization controllers 103, 118, detector 125, DAQ 130, etc. of the OCT unit 100.

For example, the main control unit 211 displays a fixation target at a position on the screen of the LCD 39 that corresponds to a fixation position that is manually or automatically set. Further, the main control unit 211 can change the display position of the fixation target displayed on the LCD 39 (continuously or stepwise). Thereby, the fixation target can be moved (that is, the fixation position can be changed). The display position and movement mode of the fixation target are set manually or automatically. Manual settings are performed using, for example, a GUI. The automatic setting is performed, for example, by the data processing unit 230.

The focus drive section 31A moves the photographic focusing lens 31 in the optical axis direction of the photographic optical system 30, and also moves the focus optical system 60 in the optical axis direction of the illumination optical system 10. Thereby, the focusing position of the photographing optical system 300 is changed. The focus drive section 31A may have a mechanism for moving the photographic focusing lens 31 and a mechanism for moving the focus optical system 60, separately. The focus drive unit 31A is controlled when performing focus adjustment.

The focusing drive unit 43A moves the OCT focusing lens 43 in the optical axis direction of the measurement optical path. Thereby, the focal position of the measurement light LS is changed. The focal position of the measurement light LS corresponds to the depth position (z position) of the beam waist of the measurement light LS.

The moving mechanism 150 moves at least the fundus camera unit 2 (optical system) three-dimensionally, for example. In a typical example, the moving mechanism 150 includes at least a mechanism for moving the fundus camera unit 2 in the x direction (horizontal direction), a mechanism for moving the fundus camera unit 2 in the y direction (vertical direction), and a mechanism for moving the fundus camera unit 2 in the z direction (depth direction). , and a mechanism for moving in the front-back direction). The mechanism for moving in the x direction includes, for example, an x stage movable in the x direction and an x movement mechanism that moves the x stage. The mechanism for moving in the y direction includes, for example, a y stage that is movable in the y direction, and a y movement mechanism that moves the y stage. The mechanism for moving in the z direction includes, for example, a z stage that is movable in the z direction and a z moving mechanism that moves the z stage. Each moving mechanism includes an actuator such as a pulse motor, and operates under control from the main control unit 211.

Control over the moving mechanism 150 is used for alignment and tracking. Tracking refers to moving the optical system of the apparatus in accordance with the eyeball movement of the eye E to be examined. When tracking is performed, alignment and focus adjustment are performed in advance. Tracking is a function that maintains a suitable positional relationship that is aligned and in focus by causing the position of the device optical system to follow the movement of the eyeballs. In some embodiments, the movement mechanism 150 is configured to be controlled to change the optical path length of the reference beam (and thus the optical path length difference between the optical path of the measurement beam and the optical path of the reference beam).

In the case of manual alignment, the optical system and the eye E are moved relative to each other by a user operating the user interface 240 (described later) so that the displacement of the eye E with respect to the optical system is canceled. For example, the main control unit 211 outputs a control signal corresponding to the operation content on the user interface 240 to the moving mechanism 150, thereby controlling the moving mechanism 150 to relatively move the optical system and the eye E to be examined.

In the case of auto-alignment, the main control unit 211 controls the moving mechanism 150 to relatively move the optical system and the eye E so that the displacement of the eye E with respect to the optical system is canceled. In some embodiments, the main control unit 211 sends a control signal so that the optical axis of the optical system substantially coincides with the axis of the eye E to be examined, and the distance of the optical system to the eye E to be examined becomes a predetermined working distance. By outputting this to the moving mechanism 150, the moving mechanism 150 is controlled to relatively move the optical system and the eye E to be examined. Here, the working distance is a default value also called the working distance of the objective lens 22, and corresponds to the distance between the eye E to be examined and the optical system at the time of measurement using the optical system (during photographing).

The main control unit 211 controls fundus photography by controlling the fundus camera unit 2 and the like. The main control unit 211 also controls OCT measurement by controlling the fundus camera unit 2, the OCT unit 100, and the like. The main control unit 211 can execute a plurality of preliminary operations before performing OCT measurement. Preliminary operations include alignment, coarse focus adjustment, optical path length difference adjustment, polarization adjustment, and fine focus adjustment. The plurality of preliminary operations are performed in a predetermined order. In some embodiments, the preliminary operations are performed in the order described above.

Note that the type and order of the preliminary operations are not limited to these and are arbitrary. For example, a preliminary operation for determining whether or not the eye E to be examined has a small pupil (small pupil determination) can be added to the preliminary operation. The small pupil determination is performed, for example, between coarse focus adjustment and optical path length difference adjustment. In some embodiments, the small pupil determination includes the following series of processes: obtaining a frontal image (anterior segment image) of the eye E to be examined; specifying an image region corresponding to the pupil; Process for determining the size of the pupil area (diameter, circumference, etc.); Process for determining whether the eye has a small pupil based on the determined size (threshold processing); If it is determined that the eye has a small pupil, the aperture 19 is Process to control. Some embodiments further include a process of approximating the pupil area to a circle or an ellipse to determine the pupil size.

The coarse focus adjustment is focus adjustment using the aforementioned split index. Note that by determining the position of the photographing focusing lens 31 based on information associating the eye refractive power and the position of the photographing focusing lens 31 acquired in advance and the measured value of the refractive power of the eye E, You can also make rough focus adjustments.

On the other hand, focus fine adjustment is performed based on the interference sensitivity of OCT measurement. For example, the position of the OCT focusing lens 43 at which the interference intensity is maximized is determined by performing OCT measurement of the eye E to obtain an interference signal and monitoring the interference intensity (interference sensitivity). Fine focus adjustment can be performed by moving the OCT focusing lens 43.

In the optical path length difference adjustment, control is performed so that the target region of the eye E to be examined is depicted at a predetermined z position within the frame of the OCT image. This control is performed on at least one of the optical path length changing section 41 and the reference driving section 114A. Thereby, the optical path length difference between the measurement optical path and the reference optical path is adjusted. A region exhibiting a characteristic brightness in an OCT image (or a region exhibiting a characteristic reflection intensity in a reflection intensity profile) is set in advance as a target region serving as a reference for optical path length difference adjustment. As a specific example, in OCT measurement of the fundus, the retinal pigment epithelial layer can be set as a reference, and in OCT measurement of the anterior segment, the corneal surface can be set as a reference. This automatic process of searching for a suitable optical path length difference is called auto-Z.

Optical path length difference adjustment is not limited to auto-Z. For example, it is possible to perform an automatic process that maintains the preferred image rendering position achieved by auto-Z. Such processing is called Z lock. In Z-lock, for example, at least one of the optical path length changing unit 41 and the reference driving unit 114A is adjusted so that the target region serving as a reference for optical path length difference adjustment is maintained at a predetermined Z position within the frame. control is performed.

In this embodiment, the Z lock reference position (z position) can be specified. That is, the optical path length difference adjustment is performed so that the state in which the target region of the eye to be examined is depicted at the designated reference position (or the Z-lock position specified based on the reference position) is maintained. In some embodiments, the Z-lock reference position is set based on the detection result of interference light obtained by OCT temporary measurement or the like. In some embodiments, the Z-lock reference position is set based on the analysis result of an OCT image formed based on the detection result of interference light. In some embodiments, the Z-lock reference position is established based on artifacts identified by analyzing OCT images. Note that the Z-lock reference position may be able to be specified with respect to the OCT image displayed on the display section 240A using the operation section 240B.

In the polarization adjustment, the polarization state of the reference light LR is adjusted to optimize the interference efficiency between the measurement light LS and the reference light LR.

(Storage 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 to be examined includes information regarding the examinee such as a patient ID and name, and information regarding the eye to be examined such as left eye/right eye identification information. Furthermore, the storage unit 212 stores various programs and data for operating the ophthalmologic apparatus 1.

(Image forming section)
The image forming unit 220 forms an OCT image of the eye E based on sampling data obtained by sampling the detection signal from the detector 125 with the DAQ 130. OCT images formed by the image forming unit 220 include A-scan images, B-scan images (tomographic images), C-scan images, and the like. Similar to conventional swept source type optical coherence tomography, this processing includes processing such as noise removal (noise reduction), filter processing, dispersion compensation, and FFT (Fast Fourier Transform). In the case of other types of OCT devices, the image forming unit 220 executes known processing depending on the type.

The image forming unit 220 is configured to include, for example, the above-described circuit board. Note that in this specification, "image data" and "images" based on the same may be equated.

(Data processing section)
The data processing unit 230 processes data acquired by photographing the eye E to be examined and performing OCT measurement. For example, the data processing section 230 performs various image processing and analysis processing on the image formed by the image forming section 220. For example, the data processing unit 230 executes various correction processes such as image brightness correction. Further, the data processing unit 230 performs various image processing and analysis processing on the images (fundus image, anterior segment image, etc.) obtained by the fundus camera unit 2.

The data processing unit 230 executes known image processing such as interpolation processing for interpolating pixels between tomographic images to form image data of a three-dimensional image of the fundus Ef. Note that the image data of a three-dimensional image means image data in which pixel positions are defined by a three-dimensional coordinate system. Image data of a three-dimensional image includes image data consisting of voxels arranged three-dimensionally. This image data is called volume data or voxel data. When displaying an image based on volume data, the data processing unit 230 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection), etc.) on this volume data so that the image can be viewed from a specific viewing direction. image data of a pseudo three-dimensional image is created. This pseudo three-dimensional image is displayed on a display device such as the display section 240A.

It is also possible to form stack data of a plurality of tomographic images as image data of a three-dimensional image. Stack data is image data obtained by three-dimensionally arranging a plurality of tomographic images obtained along a plurality of scan lines based on the positional relationship of the scan lines. In other words, stack data is image data obtained by expressing multiple tomographic images, which were originally defined by individual two-dimensional coordinate systems, using one three-dimensional coordinate system (that is, embedding them in one three-dimensional space). be.

The data processing unit 230 performs various types of rendering on the acquired three-dimensional data set (volume data, stack data, etc.) to create a B-mode image (longitudinal image, axial cross-sectional image) in an arbitrary cross section, It is possible to form C-mode images (cross-sectional images, horizontal sectional images), projection images, shadowgrams, and the like. An image of an arbitrary cross section, such as a B-mode image or a C-mode image, is formed by selecting pixels (pixels, voxels) on a specified cross-section from a three-dimensional data set. A projection image is formed by projecting a three-dimensional data set in a predetermined direction (Z direction, depth direction, axial direction). A shadowgram is formed by projecting a part of a three-dimensional data set (for example, partial data corresponding to a specific layer) in a predetermined direction. An image, such as a C-mode image, a projection image, or a shadowgram, whose viewpoint is the front side of the subject's eye is called an en-face image. In some embodiments, the image forming unit 220 forms a frontal image of the eye E to be examined.

The data processing unit 230 generates a B-mode image or a frontal image (vessel-enhanced image, angiogram) in which retinal blood vessels and choroidal blood vessels are emphasized based on data collected in time series by OCT (for example, B-scan image data). can be constructed. For example, time-series OCT data can be collected by repeatedly scanning substantially the same region of the eye E to be examined.

The data processing section 230 includes a region specifying section 231 , an artifact specifying section 232 , a Z lock position obtaining section 233 , and an optical path length difference change amount obtaining section 234 .

The site specifying unit 231 specifies a predetermined site of the eye E by analyzing the detection result of the interference light obtained by the OCT unit 100, and specifies the z position (depth position) of the specified site. In this embodiment, the region identifying section 231 analyzes the OCT image formed by the image forming section 220 based on the detection result of interference light, and identifies the z position of a predetermined region. As the predetermined region, a region in the eye E to be examined where the interference intensity is high is desirable. In some embodiments, the predetermined site is the retinal pigment epithelial layer in the fundus Ef. In some embodiments, the predetermined site is the anterior surface of the cornea in the anterior segment of the eye.

The artifact identification unit 232 identifies an artifact by analyzing the detection result of the interference light obtained by the OCT unit 100, and determines a reference position for Z lock based on the rendered position of the artifact. In this embodiment, the artifact identifying unit 232 analyzes an OCT image formed based on the detection result of interference light, identifies artifacts, and determines a Z-lock reference position. In some embodiments, a front image (projection image, etc.) of the eye E to be examined corresponding to the scan range is formed based on the scan results obtained by a plurality of B scans. The artifact identifying unit 232 identifies an artifact based on the formed frontal image of the eye E, and determines a reference position for Z lock based on the rendered position of the identified artifact. The artifact identification unit 232 identifies an aliasing artifact caused by aliasing of a predetermined portion (retina, retinal pigment epithelial layer, etc.) in an OCT image (B scan image) depicted in a frontal image. In some embodiments, the predetermined region is specified by the region identification unit 231.

FIG. 5 shows an explanatory diagram of the operation of the artifact identification unit 232 according to the embodiment. FIG. 5 schematically shows artifacts caused by aliasing when a plurality of B scans B1, B2, B3, . . . are executed within a predetermined scan area.

If the Z-lock position is not suitable, the B-scan image formed by the image forming unit 220 based on the scan results obtained by B-scans B1, B2, B3, . Is displayed. In this case, by changing the Z lock position (or Z lock reference position), it is possible to obtain an image without folding.

The data processing unit 230 converts the front image FI0, such as a projection image in the depth direction, including at least one depth position of folding positions P1, P2, P3, . . . at the upper end of each B-scan image, into multiple B-scan It is formed based on the scan results obtained by B1, B2, B3, . A folding artifact corresponding to the locus of the folding position in each B-scan is depicted in the peripheral area of the front image FI0. The peripheral areas include an upper right area, a right area, a lower right area, a lower area, a lower left area, a left area, an upper left area, an upper area, and the like. The artifact specifying unit 232 specifies a Z-lock reference position based on the distance LL to the turning position of the artifact at the upper end or lower end of the front image FI0, with the left end or right end of the front image FI0 as a reference. The artifact specifying unit 232 is capable of specifying the turning position of the artifact based on brightness information such as a front image. In some embodiments, control information in which a Z-lock reference position is associated with the distance LL is stored in advance in, for example, the artifact identification unit 232 or the storage unit 212. The artifact identifying unit 232 determines the Z-lock reference position by referring to the control information.

In some embodiments, the artifact identification unit 232 determines the Z-lock reference position based on the tomographic image of the eye E formed by the image forming unit 220. The artifact identifying unit 232 identifies a predetermined layer region (for example, retinal pigment epithelium layer) in the retina of the eye E based on the acquired tomographic image, and extracts the specified layer region from the upper end of the tomographic image. The reference position of the Z lock position can be determined based on the distance to.

The Z lock position acquisition unit 233 acquires (specifies) a Z lock position (z position) for B scan in a preset scan area. As described above, in this embodiment, the Z-lock reference position can be specified. When a plurality of B-scans are performed in the scan area, Z-lock positions of other B-scans are acquired based on a Z-lock reference position specified for at least one B-scan. In some embodiments, when the Z lock reference position z0 is specified, the Z lock position acquisition unit 233 determines the Z lock position (z0+Δz) and (z0−Δz) for any of the other B scans. Get at least one. The remaining B-scan Z lock positions are specified based on the designated Z lock reference position or the Z lock position acquired by the Z lock position acquisition unit 233. This Z-lock position is specified according to linear interpolation, a quadratic or higher order spline curve, or a predetermined function.

In some embodiments, Δz is a fixed value. In some embodiments, Δz includes a scan position, a scan range, a refractive power of the eye E to be examined, information indicating whether the eye E to be examined is highly myopic, an OCT image (B scan image) of the eye E to be examined, and the It is set according to at least one of the B-scan images of the eye E obtained by the B-scan in the direction intersecting the B-scan. For example, control information in which Δz is associated with a scan position or the like is stored in advance in, for example, the Z lock position acquisition unit 233 or the storage unit 212. The Z-lock position acquisition unit 233 acquires the Z-lock position by referring to the control information.

The optical path length difference change amount acquisition unit 234 specifies the amount of change in the difference between the optical path length of the measurement optical path and the optical path length of the reference optical path in order to control auto-Z or Z-lock.

When performing auto-Z, the ophthalmological apparatus 1 controls the optical system to perform OCT measurement of the eye E (for example, the fundus Ef). In this OCT measurement, for example, the eye E to be examined is repeatedly scanned at a predetermined frequency. That is, OCT measurement using the same scan pattern is repeatedly performed on the eye E to be examined to which the fixation target is presented. In some embodiments, substantially the same cross section of the eye E to be examined is scanned. The optical path length difference change amount acquisition unit 234 analyzes the detection results (reflection intensity profile, OCT image, etc.) of the interference light LC repeatedly acquired by this OCT measurement, and generates an image (image of the fundus Ef) based on the detection results. ) to a specific position in the frame.

In some embodiments, the optical path length difference change amount acquisition unit 234 calculates the difference between the Z position of the predetermined part specified by the part identification unit 231 and the Z lock position, and calculates the optical path length corresponding to the calculated difference. Get the difference change amount.

Note that the information acquired by the optical path length difference change amount acquisition unit 234 is not limited to the amount of change in the optical path length difference (optical path length) itself. For example, the content of control of the optical path length changing unit 41 or the reference drive unit 114A (such as the number of transmitted pulses), and the information obtained during the process of acquiring the amount of change (such as the amount of shift in the position of the image in the z direction within the frame, etc.) ) may be information that is substantially equivalent to the amount of change in the optical path length difference.

In some embodiments, control information is associated in advance with the amount of change in optical path length difference (or control information corresponding to the amount of change) corresponding to the difference between the Z position of a predetermined portion with respect to the Z lock position. It is stored in the length difference change amount acquisition unit 234 (or storage unit 212). The optical path length difference change amount obtaining unit 234 obtains the change amount of the optical path length difference to be changed by referring to the control information.

The main control unit 211 executes auto-Z by controlling at least one of the optical path length change unit 41 and the reference drive unit 114A based on the change amount acquired by the optical path length difference change amount acquisition unit 234. Such auto-Z control is the same as that in Japanese Patent Application Laid-Open No. 2016-041221, so a detailed explanation will be omitted.

In Z-lock, as in the case of auto-Z, a cross-section of the eye E (for example, fundus Ef) is repeatedly scanned at a predetermined frequency. In some embodiments, substantially the same cross section of the eye E to be examined is scanned. Furthermore, the optical path length difference change amount acquisition unit 234 analyzes the detection results of the interference light LC repeatedly acquired by this OCT measurement, thereby determining the optical path length difference for placing the image of a predetermined part at the Z lock position. Get the amount of change.

In some embodiments, the optical path length difference change amount acquisition unit 234 calculates the difference between the Z lock position set for the scan performed immediately before and the Z lock position set for the scan, and The amount of change in the optical path length difference corresponding to the difference is obtained. In some embodiments, the optical path length difference change amount obtaining unit 234 obtains the difference between the Z position of the predetermined part specified by the part specifying part 231 and the Z lock position for each scan, and corresponds to the obtained difference. Obtain the amount of change in the optical path length difference.

The main control unit 211 executes Z lock by controlling at least one of the optical path length changing unit 41 and the reference drive unit 114A based on the change amount acquired by the optical path length difference change amount acquisition unit 234. Such Z-lock control is the same as that in Japanese Patent Application Laid-Open No. 2016-041221, so a detailed explanation will be omitted.

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

(user interface)
User interface 240 includes a display section 240A and an operation section 240B. The display section 240A includes the display device of the arithmetic and control unit 200 and the display device 3 described above. The operation section 240B is configured to include the operation device of the arithmetic and control unit 200 described above. The operation unit 240B may include various buttons and keys provided on the housing or outside of the ophthalmological apparatus 1. For example, when the fundus camera unit 2 has a housing similar to a conventional fundus camera, the operation section 240B may include a joystick, an operation panel, etc. provided in this housing. Furthermore, the display section 240A may include various display devices such as a touch panel provided on the housing of the fundus camera unit 2.

Note that the display section 240A and the operation section 240B do not need to be configured as separate devices. For example, it is also possible to use a device such as a touch panel that has a display function and an operation function integrated. In that case, the operation unit 240B is configured to include this touch panel and a computer program. The content of the operation on the operation unit 240B is input to the control unit 210 as an electrical signal. Further, operations and information input may be performed using a graphical user interface (GUI) displayed on the display section 240A and the operation section 240B.

[About measurement light scan and OCT image]
Here, the scan of the measurement light LS and the OCT image will be explained.

Examples of scanning modes of the measurement light LS by the ophthalmologic apparatus 1 include horizontal scan, vertical scan, cross scan, radial scan, circle scan, concentric circle scan, and spiral (spiral) scan. These scanning modes are selectively used as appropriate, taking into account the observation site of the eye E, the target of analysis (retinal thickness, etc.), the time required for scanning, the precision of scanning, and the like.

In the horizontal scan, the scanned region is scanned in the horizontal direction (x direction) with the measurement light LS. The horizontal scan also includes a mode in which the measurement light LS is scanned along a plurality of horizontally extending scan lines arranged in the vertical direction (y direction). In this aspect, it is possible to arbitrarily set the interval between scan lines. Further, by sufficiently narrowing the interval between adjacent scan lines, the aforementioned three-dimensional image can be formed (three-dimensional scan). The same applies to vertical scanning.

In the cross scan, the measurement light LS scans the scanned region along a cross-shaped locus made up of two linear trajectories (straight line trajectories) that are orthogonal to each other. In the radiation scan, a scan site is scanned with the measurement light LS along a radial trajectory consisting of a plurality of linear trajectories arranged at a predetermined angle. Note that the cross scan is an example of a radiation scan.

In the circular scan, a scanning region is scanned with the measurement light LS along a circular trajectory. In the concentric scan, a scanning region is scanned with the measurement light LS along a plurality of circular trajectories arranged concentrically around a predetermined center position. A circular scan is an example of a concentric scan. In the helical scan, the scanning region is scanned with the measurement light LS along a spiral (spiral) trajectory while gradually decreasing (or increasing) the radius of rotation.

The optical scanner 42 is configured to scan the scanned region with the measurement light LS in directions orthogonal to each other, so it can scan independently in the x direction and the y direction with the measurement light LS. Furthermore, by simultaneously controlling the orientations of the two galvanometer mirrors included in the optical scanner 42, it is possible to scan with the measurement light LS along an arbitrary trajectory on the xy plane. Thereby, various scanning modes as described above can be realized.

By scanning with the measurement light LS in the manner described above, it is possible to obtain a tomographic image in a plane defined by the direction along the scan line (scanning locus) and the fundus depth direction (z direction). Moreover, especially when the interval between scan lines is narrow, the above-mentioned three-dimensional image can be obtained.

The area on the subject's eye E that is the scanning target of the measurement light LS as described above, that is, the area on the subject's eye E that is the subject of OCT measurement is called a scan area. A scan area in three-dimensional scanning is a rectangular area in which a plurality of horizontal scans are arranged. Further, the scan area in the concentric scan is a disk-shaped area surrounded by the locus of the circular scan with the largest diameter. Further, the scan area in the radiation scan is a disk-shaped (or polygonal) area connecting both end positions of each scan line.

[About specifying the Z lock position]
For example, the main control unit 211 causes the display unit 240A to display the image being scanned live.

FIG. 6 shows an example of an image displayed on the display section 240A. FIG. 6 schematically represents a tomographic image display area DR1 and a front image display area DR2 provided in the display area DR on the display screen of the display unit 240A.

For example, the main control unit 211 controls the fundus camera unit 2 to display the acquired fundus image on the display unit 240A. The user can specify a scan area at a desired position in the fundus image displayed on the display section 240A by performing a predetermined operation on the operation section 240B. The main control unit 211 executes OCT measurement on the designated scan area by controlling the OCT unit 100 and the like. The main control unit 211 causes the image forming unit 220 to form a B-scan image based on the obtained scan result (detection result of interference light), and causes the data processing unit 230 to form a projection image using the scan result. . The main control unit 211 causes the formed B-scan image to be displayed live in the tomographic image display area DR1. The main control unit 211 also causes the formed projection image to be displayed in the front image display area DR2.

In some embodiments, a scan area is specified by operating the operation unit 240B on the fundus image or projection image displayed in the front image display area DR2.

The Z-lock reference position specified by the artifact identification unit 232 and the Z-lock position specified by the Z-lock position acquisition unit 233 will be described below.

(First specification example of Z lock position)
FIG. 7 shows a schematic diagram for explaining an example of specifying the Z lock position according to the embodiment.

For example, for a front image (fundus image or projection image) FI of the fundus Ef of the eye E to be examined, there is a scan area SA and a plurality of B scans B1 to BN (N is an integer of 2 or more) performed within the scan area SA. The scan position is set. It is assumed that each B-scan is a line scan. The main control unit 211 sequentially executes a plurality of B scans B1 to BN (N is an integer greater than or equal to 2) on a region corresponding to the set scan area SA. For convenience of explanation, it is assumed that the B scans are executed in the order from B scan B1 to B scan BN. The artifact identification unit 232 determines Z for a B scan Bj (1≦j≦N, j is an integer), which is one of the plurality of B scans B1 to BN, based on the frontal image obtained by OCT provisional measurement or the like. Specify the lock reference position zz. In some embodiments, the artifact identifying unit 232 specifies the Z-lock reference position zz based on a tomographic image obtained by preliminary OCT temporary measurement or the like.

The main control unit 211 sets Z-lock positions zj for other B-scans B1 to B(j-1) and B(j+1) to BN based on the specified Z-lock reference position zz. The optical path length difference change amount acquisition unit 234 acquires the amount of change in the optical path length difference for arranging the image of a predetermined part at the designated Z-lock position zz. In each B-scan, the main control unit 211 sequentially executes a plurality of B-scans B1 to BN by controlling at least one of the optical path length changing unit 41 and the reference drive unit 114A based on the obtained change amount.

(Second designation example of Z lock position)
FIG. 8 shows a schematic diagram for explaining an example of specifying the Z lock position according to the embodiment.

In this designation example, as in the first designation example, the artifact identifying unit 232 designates the Z-lock reference position zz for B-scan Bj, which is one of the plurality of B-scans B1 to BN.

The Z-lock position acquisition unit 233 performs B-scan Bi (1≦i<j, i is an integer) and B-scan k (j<k≦N, k is an integer) based on the specified Z-lock reference position zzj. Obtain the Z lock position (zj-Δz) (Δz is a positive number) (or (zz+Δz)) for the The Z-lock position acquisition unit 233 acquires the z-lock position (zj-Δz) set for B-scan Bi, the z-lock position zj set for B-scan Bj, and the z-lock position (zj-Δz) set for B-scan Bk. Z lock positions for the remaining B scans are obtained by performing predetermined interpolation processing (for example, linear interpolation, spline interpolation) based on Δz). Here, the remaining B scans are B scans B1 to B(i-1), B(i+1) to B(j-1), B(j+1) to B(k-1), and B(k+1) to BN. It is.

That is, when the Z lock reference position zz (first reference position) is set for B scan Bj (first B scan), the reference position zz is set for B scan Bi (second B scan). On the other hand, a Z lock position zi (second reference position) shifted in the depth direction is set, and the Z lock position Zk is set based on the reference position zzj and the Z lock position zi with respect to the B scan Bk (third B scan). (third reference position) is set.

The main control unit 211 controls other B scans B1 to B(i-1), B(i+1) to B(j-1) based on the specified Z-lock reference position zz and the acquired Z-lock position. , B(j+1) to B(k-1), and B(k+1) to BN. The optical path length difference change amount acquisition unit 234 acquires the amount of change in the optical path length difference for arranging the image of a predetermined part at the designated Z-lock position for each B-scan. In each B-scan, the main control unit 211 sequentially executes a plurality of B-scans B1 to BN by controlling at least one of the optical path length changing unit 41 and the reference drive unit 114A based on the obtained change amount.

As mentioned above, Δz is a fixed value or a variable value.

(Third example of specifying Z lock position)
FIG. 9 shows a schematic diagram for explaining an example of specifying the Z lock position according to the embodiment.

In this specification example, the artifact specifying unit 232 specifies Z-lock reference positions zi and zk for B scans Bi and Bk, which are any two of the plurality of B scans B1 to BN, respectively.

The Z-lock position acquisition unit 233 acquires the Z-lock position zz for the B-scan Bj with respect to the specified Z-lock reference positions zi, zk. The Z lock position acquisition unit 233 performs a predetermined interpolation process (for example, linear interpolation, spline interpolation) based on the z lock position zi set in the B scan Bi and the z lock position zk set in the B scan Bk. By doing this, the Z lock position zz of the B scan Bj is obtained. Similarly, the Z lock position acquisition unit 233 performs B scans B1 to B(i-1), B(i+1) to B(j-1), B(j+1) to B(k-1), B(k+1) ~ Acquire the Z lock position for each BN.

That is, the Z-lock reference position zi (first reference position) is set for the B-scan Bi (first B-scan), and the Z-lock reference position zk is set for the B-scan Bk (second B-scan). (second reference position) is set. Further, a Z lock position zz (third reference position) specified based on the reference positions zi and zk is set for the B scan Bj (third B scan).

The main control unit 211 controls other B scans B1 to B(i-1), B(i+1) to B(k- 1) Set the Z lock position for B(k+1) to BN. The optical path length difference change amount acquisition unit 234 acquires the amount of change in the optical path length difference for arranging the image of a predetermined part at the designated Z-lock position for each B-scan. In each B-scan, the main control unit 211 sequentially executes a plurality of B-scans B1 to BN by controlling at least one of the optical path length changing unit 41 and the reference drive unit 114A based on the obtained change amount.

(Fourth designation example of Z lock position)
FIG. 10 shows a schematic diagram for explaining an example of specifying the Z lock position according to the embodiment.

In this specification example, the artifact specifying unit 232 specifies Z-lock reference positions zi, zz, and zk for any three B scans Bi, Bj, and Bk of the plurality of B scans B1 to BN, respectively. do. For example, if multiple B-scans B1 to BN that are executed sequentially are divided into early, middle, and late periods, specify the Z-lock reference position zi for the B-scan Bi that is executed in the early period, and A Z-lock reference position zz is specified for the B-scan Bj to be executed, and a Z-lock reference position zk is specified for the B-scan Bk to be executed later.

In some embodiments, in the second designation example, when the Z-lock reference position zz is specified for the B-scan Bj executed in the middle period, the Z-lock reference position zz for the B-scan Bi executed in the earlier period is specified. The Z lock position (zj - Δz1) (or (zj + Δz1)) is set as the reference position zi, and the Z lock position (zj - Δz2) (or (zz+Δz2)) may be set. In some embodiments, Δz1 is equal to Δz2. Like Δz, Δz1, Δz2 may be fixed values or variable values.

The remaining B-scan Z lock positions are specified based on the designated Z lock reference position or the Z lock position acquired by the Z lock position acquisition unit 233.

That is, a Z-lock reference position zj (first reference position) is set for B-scan Bj (first B-scan), and a Z-lock reference position zk is set for B-scan Bk (second B-scan). (second reference position) is set. Also, for any one of B scans B(j+1) to B(k-1) (third B scan), the Z lock position (third reference position) specified based on the reference positions zzj and zk is Set.

The main control unit 211 controls other B scans B1 to B(i-1) and B(i+1) to B based on the specified Z lock reference positions zi, zz, and zk and the acquired Z lock position. Set Z lock positions for (j-1), B(j+1) to B(k-1), and B(k+1) to BN. The optical path length difference change amount acquisition unit 234 acquires the amount of change in the optical path length difference for arranging the image of a predetermined part at the designated Z-lock position for each B-scan. In each B-scan, the main control unit 211 sequentially executes a plurality of B-scans B1 to BN by controlling at least one of the optical path length changing unit 41 and the reference drive unit 114A based on the obtained change amount.

(others)
In some embodiments, the above Δz, Δz1, and Δz2 include the scan position, scan range, refractive power of the eye E, information indicating whether the eye E is highly myopic, and the eye E It is set according to at least one of an OCT image (B-scan image) of , and a B-scan image of the eye E obtained by a B-scan in a direction intersecting the B-scan.

The ophthalmological apparatus 1 according to the embodiment collects scan data over a wider range by providing one or more scan areas in which the scan center position is displaced from the scan center position after the alignment of the apparatus optical system with respect to the eye E is completed. It is possible to do so.

11 to 13 show examples of scan ranges that can be set by the ophthalmologic apparatus 1 according to the embodiment.

In FIG. 11, scan areas SC1 to SC4 are set to include scan center position O with respect to scan area SC0 defined by scan center position O after alignment is completed. Each scan area is arranged so that its peripheral area overlaps with the peripheral area of an adjacent scan area. In some embodiments, the scan area sizes of scan areas SC0-SC5 are the same.

In FIG. 12, scan areas SC1 to SC4 are set so that the peripheral areas of scan area SC0 defined by scan center position O after completion of alignment overlap. In some embodiments, the scan area sizes of scan areas SC0-SC5 are the same.

In FIG. 13, similarly to FIG. 12, scan areas SC1 to SC4 are set so that the peripheral areas of scan area SC0 defined by scan center position O after completion of alignment overlap. Note that the peripheral area on the right side of scan area SC3 is arranged so as to overlap the peripheral area on the left side of scan areas SC2 and SC4. The peripheral area on the left side of scan area SC1 is arranged so as to overlap the peripheral area on the right side of scan areas SC2 and SC4. In some embodiments, the size of the scan area of scan areas SC0, SC2, SC4 is the same, the size of the scan area of scan areas SC1, SC3 is the same, and the size of scan area SC1 is the size of scan area SC0. bigger.

In some embodiments, the above Δz, Δz1, and Δz2 are predetermined in correspondence with the scan area positions (scanning position, imaging position, imaging site) shown in FIGS. 11 to 13.

In some embodiments, Δz, Δz1, Δz2 for setting the Z-lock position for a B-scan in any of scan areas SC1-SC4 is the scan position of a given B-scan in scan area SC0 and the corresponding B-scan. It is set according to the distance from the scan position.

In some embodiments, Δz, Δz1, and Δz2 for setting the Z lock position for the B scan in any of scan areas SC1 to SC4 are representative positions of scan area SC0 (for example, scan center position O) and the representative position of the scan area.

In some embodiments, Δz, Δz1, Δz2 for setting the Z-lock position for the B-scan in any of the scan areas SC1-SC4 are the same as those of the ophthalmological device 1 for scanning the scan areas SC1-SC4. Set according to control information. Examples of the control information include control information for the LCD 39 to change the fixation position to scan the scan areas SC1 to SC4, and control information to control the optical scanner 42 to scan the scan areas SC1 to SC4. There is.

FIG. 14 shows another example of the scan range that can be set by the ophthalmologic apparatus 1 according to the embodiment.

In FIG. 14, a scan area SC1 is set to include the scan center position O with respect to a scan area SC0 defined by the scan center position O after alignment is completed. The size of scan area SC1 is larger than the size of scan area SC0.

In some embodiments, the above Δz, Δz1, and Δz2 are predetermined corresponding to the size of the scan area.

In some embodiments, Δz, Δz1, Δz2 for setting the Z-lock position for B-scan in scan area SC1 is the size of scan area SC1 (3-dimensional scan range) relative to the size of scan area SC0 (3-dimensional scan range). dimensional scan range). Similarly, in FIG. 13, Δz, Δz1, and Δz2 for setting the Z lock position for the B scan in the scan area SC1 (SC3) are the scan area SC1 for the size of the scan area SC0 (three-dimensional scan range). It is set according to the size (three-dimensional scan range) of (SC3).

In some embodiments, the above Δz, Δz1, and Δz2 are predetermined in accordance with information about the eye E to be examined. Information on the eye E to be examined includes, for example, a reflex measurement result (refractive power) obtained by a reflex measurement separately performed on the eye E to be examined, information indicating whether the eye E to be examined is highly myopic, etc. be. That is, for B scans other than the B scan in which the Z lock reference position z0 is set, when the eye E to be examined is severely myopic, the Z lock position is set at a position shifted by the first shift value with respect to the reference position z0. When the eye E to be examined is not severely myopic, a Z lock position is set that is shifted by a second shift value smaller than the first shift value with respect to the reference position z0. In some embodiments, the reflex measurement result or information indicating whether or not the eye E to be examined is highly myopic is included in the eye information to be examined.

In some embodiments, the above Δz, Δz1, and Δz2 are obtained based on standard data statistically derived from measurement results of a large number of normal eyes.

In some embodiments, for B-scans other than the B-scan in which the Z-lock reference position z0 is set, the reference position z0 is shifted by a shift value selected from a plurality of predetermined shift values. It is set as follows. The plurality of shift values may be predetermined based on the above standard data.

In some embodiments, Δz, Δz1, and Δz2 are predetermined in accordance with an analysis result of an OCT image (B-scan image) of the eye E to be examined. As an OCT image of the eye E to be examined, for example, a B-scan image obtained by a B-scan performed during the three-dimensional scan, a B-scan image of the eye E to be examined obtained by a B-scan in a direction intersecting the B-scan. and so on. That is, in some embodiments, for B scans other than the B scan in which the Z lock reference position z0 is set, the Z lock position is set based on an image based on the detection result of interference light obtained by OCT measurement. be done. Furthermore, in some embodiments, for B scans other than the B scans in which the Z lock reference position z0 is set, by scanning in a direction that intersects the scanning direction of the B scan in which the Z lock reference position z0 is set. It is set based on the obtained interference light detection result. As the scanning mode of the B-scan in the direction intersecting the B-scan, for example, a horizontal scan, a vertical scan, a cross scan, a radial scan, a circle scan, a concentric circle scan, a spiral (spiral) scan, etc. are used.

In the embodiments described above, the image forming section 220 or the data processing section 230 is an example of an "image forming section" according to the embodiment. Further, the data processing unit 230 is an example of an “analysis unit” according to the embodiment.
[motion]
The operation of the ophthalmologic apparatus 1 according to the embodiment will be described.

FIG. 15 shows a flowchart of an example of the operation of the ophthalmologic apparatus 1 according to the embodiment.

(S1: Set scan area)
First, the user sets a scan area for the eye E using the operation unit 240B.

(S2: Alignment)
The main control unit 211 executes alignment. That is, the main control unit 211 controls the alignment optical system 50 to project the alignment index onto the eye E to be examined. At this time, a fixation target by the LCD 39 is also projected onto the eye E to be examined. The main control unit 211 controls the moving mechanism 150 based on the amount of movement of the optical system specified based on the received light image acquired by the image sensor 35, for example, and moves the optical system with respect to the eye E by the amount of movement. Move relatively. The main control unit 211 repeatedly executes this process.

(S3: Focus)
When the alignment is completed, the main control unit 211 starts focus adjustment. For example, the main control unit 211 starts acquiring a front image of the fundus Ef, and controls the focus optical system 60 to project a split index onto the fundus Ef. The main control unit 211 controls the focusing drive unit 31A based on the amount of movement of the optical system specified based on the received light image acquired by the image sensor 35, for example, and moves the photographing focusing lens 31 by the amount of movement. let Here, the main control unit 211 controls the focusing drive unit 43A to move the OCT focusing lens 43 by the amount of movement. The main control unit 211 repeatedly executes this process.

In some embodiments, multiple preliminary operations are performed in step S2 or step S3. Preliminary operations include alignment, coarse focus adjustment, optical path length difference adjustment, polarization adjustment, and fine focus adjustment.

(S4: Auto Z)
The main control unit 211 starts OCT measurement. In this OCT measurement, substantially the same cross section of the eye E to be examined (for example, the fundus Ef) is repeatedly scanned at a predetermined frequency. Next, the main control unit 211 executes auto-Z based on the acquired OCT image (or reflection intensity profile, etc.), similar to the method disclosed in Japanese Patent Application Laid-Open No. 2016-041221.

Here, the main control unit 211 causes the display unit 240A to display the OCT image live.

(S5: OCT provisional measurement)
Next, the main control unit 211 executes OCT provisional measurement by controlling the OCT unit 100 and the like. Next, the main control unit 211 controls the image forming unit 220 and the data processing unit 230 to form a projection image of the eye E to be examined.

(S6: Specify the reference position of Z lock)
Next, the main control unit 211 identifies artifacts caused by aliasing based on the projection image formed in step S5, and sets the Z-lock reference position corresponding to the rendering position of the identified artifact to a predetermined B-scan. Set against.

Note that if no artifact is identified in step S6, a predetermined Z-lock reference position is set for a predetermined B scan.

(S7: Obtain Z lock position)
The main control unit 211 causes the Z lock position acquisition unit 233 to acquire the Z lock position for other B scans as described above based on the Z lock reference position specified in step S6.

(S8: Change optical path length difference)
Subsequently, the main control unit 211 sequentially executes B scans. For example, the main control unit 211 causes the optical path length difference change amount acquisition unit 234 to acquire the change amount of the optical path length difference based on the Z lock position acquired in step S7. Thereafter, the main control section 211 controls at least one of the optical path length changing section 41 and the reference driving section 114A based on the obtained change amount of the optical path length difference.

(S9: Scan)
The main control unit 211 deflects the measurement light LS by controlling the optical scanner 42 and performs a B scan on the eye E to be examined.

(S10: Form a tomographic image)
The main control unit 211 causes the image forming unit 220 to form a tomographic image based on the scan result obtained in step S9.

(S11: Display)
The main control unit 211 displays the tomographic image formed in step S10 in the tomographic image display region DR1 of the display unit 240A.

(S12: Next?)
The main control unit 211 determines whether to perform the next B scan. The main control unit 211 determines whether to perform the next B scan based on the scan area set in step S1 or the operation details on the operation unit 240B.

When it is determined that the next B-scan is to be performed (S12: Y), the operation of the ophthalmologic apparatus 1 moves to step S8. When it is determined that the next B-scan is not to be performed (S12:N), the operation of the ophthalmologic apparatus 1 moves to step S13.

(S13: Form frontal image)
When it is determined in step S12 that the next B scan is not to be performed (S12: N), the main control unit 211 causes the data processing unit 230 to form a projection image based on the scan data of the scan area set in step S1. let

(S14: Display)
Next, the main control unit 211 displays the projection image formed in step S13 in the front image display area DR2 of the display unit 240A. This is the end of the operation of the ophthalmologic apparatus 1 (END).

[effect]
An ophthalmologic apparatus and a control method thereof according to an embodiment will be described.

Some embodiments include an interference optical system (an optical system included in the OCT unit 100), an image forming section (220, data processing section 230), an analysis section (data processing section 230), and a control section (210). An ophthalmologic apparatus (1) comprising: The interference optical system is configured to be able to change the optical path length difference between the measurement optical path and the reference optical path. The interference optical system splits the light (L0) from the light source (light source unit 101) into measurement light (LS) and reference light (LR), and irradiates the eye (E) with the measurement light via the measurement optical path. , detects interference light (LC) between the return light from the subject's eye and the reference light that has passed through the reference optical path. The image forming unit forms an image of the eye to be examined based on the detection result of the interference light. The analysis unit specifies a reference position in the depth direction of the B scan (Z-lock reference position) for the eye to be examined by analyzing the image (projection image, tomographic image) formed by the image forming unit. The control unit controls the interference optical system and changes the optical path length difference in each B-scan so that the image based on the detection result of the interference light is placed at the reference position. Execute B-scan.

In such a configuration, for the B scan performed on the eye to be examined, a reference position in the depth direction is specified based on the image of the eye to be examined, and an image based on the detection result of interference light is placed at the reference position. A plurality of B-scans are performed on the eye to be examined so that the eye is examined. As a result, even if the measurement range by OCT measurement becomes wider in the x-y direction or deeper in the z-direction, depending on the curvature of the eyeball, the region of interest may be depicted at the edge of the imaging range or may fall outside the imaging range. You will be able to avoid situations where this happens. As a result, it becomes possible to reduce the burden on examiners and subjects when performing OCT measurements.

In some embodiments, the analysis unit identifies the reference position based on a frontal image of the eye to be examined that corresponds to a scan range based on scan results obtained from a plurality of B-scans.

According to this configuration, the reference position for Z lock is specified based on the frontal image of the subject's eye, so depending on the curvature state of the eyeball, the region of interest may be depicted at the edge of the imaging range, or the You will be able to reliably avoid situations where you are out of range.

In some embodiments, the analysis unit identifies the reference position based on artifacts caused by aliasing in the B-scan image depicted in the frontal image.

According to such a configuration, it becomes possible to easily obtain a B-scan image without aliasing, and it becomes possible to reduce the burden on the examiner and the subject when performing OCT measurement.

In some embodiments, the analysis unit identifies the reference position based on the distance from the left or right edge of the front image to the position of the artifact at the top or bottom of the front image.

According to such a configuration, it becomes possible to identify artifacts with very simple processing, and it becomes possible to easily reduce the burden on examiners and subjects when performing OCT measurement.

In some embodiments, the image forming unit forms a tomographic image of the eye to be examined based on the detection result of the interference light, and the analyzing unit identifies the reference position based on the tomographic image.

According to this configuration, the reference position for Z lock is specified based on the tomographic image of the eye to be examined, so depending on the curvature of the eyeball, the region of interest may be depicted at the edge of the imaging range, or the You will be able to reliably avoid situations where you are out of range.

In some embodiments, the analysis unit identifies a predetermined layer region in the retina of the subject's eye based on the tomographic image, and determines the reference based on the distance from the top of the tomographic image to the identified predetermined layer region. Locate.

According to such a configuration, it becomes possible to identify artifacts with very simple processing, and it becomes possible to easily reduce the burden on examiners and subjects when performing OCT measurement.

In some embodiments, the plurality of B-scans includes a first B-scan, a second B-scan, and a third B-scan, and the analyzer includes a first B-scan for the first B-scan. identifying a reference position, identifying a second reference position for a second B-scan, and identifying a third reference position for a third B-scan based on the first reference position and the second reference position; , the control unit executes the first B-scan, the second B-scan, and the third B-scan by controlling the interference optical system.

With such a configuration, at least two reference positions can be specified, so depending on the curvature state of the eyeball, the region of interest may be depicted at the edge of the imaging range or out of the imaging range. Situations can be easily avoided. As a result, it becomes possible to reduce the burden on examiners and subjects when performing OCT measurements.

In some embodiments, the analysis unit sets the second reference position for the second B-scan by shifting in the depth direction with respect to the first reference position.

With this configuration, multiple Z-lock reference positions can be set for multiple B-scans, so depending on the curvature state of the eyeball, the region of interest may be depicted at the edge of the imaging range, or the image may This will allow you to avoid situations where you are out of range. As a result, it becomes possible to reduce the burden on examiners and subjects when performing OCT measurements.

In some embodiments, the analysis unit sets the second reference position according to the distance between the scan position of the first B-scan and the scan position of the second B-scan.

With such a configuration, the Z-lock position is set according to the scan position, so even if the measurement range becomes wide or the degree of curvature of the eyeball increases, such as in severe myopia, the part of interest will not be visible in the image. This makes it possible to avoid situations where the image is drawn at the edge of the imaging range or out of the imaging range.

In some embodiments, the analysis unit sets the second reference position according to a three-dimensional scan range including the second B-scan with respect to a three-dimensional scan range including the first B-scan.

With this configuration, the Z-lock position is set according to the scan range, so even if the measurement range is wide or the degree of curvature of the eyeball is large, such as in severe myopia, the part of interest will not be visible in the image. This makes it possible to avoid situations where the image is drawn at the edge of the imaging range or out of the imaging range.

In some embodiments, the analysis unit sets the second reference position according to the refractive power of the eye to be examined.

With this configuration, the Z-lock position is set according to the refractive power of the eye to be examined, so even if the measurement range is wide or the degree of curvature of the eyeball is large, such as in severely myopic eyes, It is possible to avoid situations in which the site is depicted at the edge of the imaging range or out of the imaging range.

In some embodiments, the analysis unit sets the second reference position to a position shifted by the first shift value with respect to the first reference position when the eye to be examined is highly myopic, and the analysis unit sets the second reference position to a position shifted by the first shift value when the eye to be examined is not highly myopic. At this time, the second reference position is set at a position shifted by a second shift value smaller than the first shift value with respect to the second reference position.

According to such a configuration, the Z lock position is set according to information indicating whether or not the eye to be examined is highly myopic, so the measurement range is widened and the degree of curvature of the eyeball is Even if the target region becomes larger, it is possible to avoid situations where the target region is depicted at the edge of the imaging range or moves out of the imaging range.

In some embodiments, the analysis unit sets the second reference position to be shifted by a shift value selected from a plurality of predetermined shift values with respect to the first reference position.

According to such a configuration, the Z lock position is set using a shift value selected from a plurality of predetermined shift values, so the measurement range is widened, and the measurement range is widened and the shift value is Even when the degree of curvature increases, it is possible to easily avoid situations in which the region of interest is depicted at the edge of the imaging range or deviates from the imaging range.

In some embodiments, the analysis unit sets the second reference position based on the detection result of interference light obtained by scanning in a direction intersecting the scanning direction of the first B-scan.

According to such a configuration, the Z lock position is set based on the detection result of interference light obtained by scanning in a direction intersecting the scan direction of the first B scan, so that the target region is within the imaging range. This makes it easier to predict situations where the image is drawn at the edge or out of the imaging range. As a result, even if the measurement range becomes wider or the degree of curvature of the eyeball increases, such as in highly myopic eyes, it will be ensured that the area of interest will not be depicted at the edge of the imaging range or will fall outside the imaging range. It becomes possible to avoid this.

In some embodiments, the controller causes the first B-scan, the third B-scan, and the second B-scan to be performed in order in a direction intersecting the scan direction of the first B-scan.

According to such a configuration, even when using the reference position specified for the third B-scan, the situation where the region of interest is depicted at the edge of the imaging range or deviates from the imaging range can be avoided. It becomes easier to do.

The above embodiment can be applied to specifying a Z-lock reference position for any number of B-scans in a scan area. For example, it is possible to specify the Z lock reference position for any four or more B scans.

A computer program for implementing the above embodiments can be stored in any computer-readable recording medium. Examples of this 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.), etc. It is possible to use

It is also possible to send and receive this program via a network such as the Internet or LAN.

1 Ophthalmological apparatus 2 Fundus camera unit 10 Illumination optical system 30 Photographic optical system 31 Photographic focusing lens 41 Optical path length changing section 42 Optical scanner 50 Alignment optical system 60 Focusing optical system 100 OCT unit 101 Light source unit 200 Arithmetic control unit 210 Control section 211 Main control unit 212 Storage unit 220 Image forming unit 230 Data processing unit 231 Site identification unit 232 Artifact identification unit 233 Z lock position acquisition unit 234 Optical path length difference change amount acquisition unit 240A Display unit 240B Operation unit E Eye to be examined LS Measuring light LR Reference Optical LC interference light

Claims (2)

The optical path length difference between the measurement optical path and the reference optical path can be changed, and the light from the light source is divided into measurement light and reference light, and the measurement light that has passed through the measurement optical path is irradiated onto the subject's eye. an interference optical system that detects interference light between the return light from the optometry and the reference light that has passed through the reference optical path;
an image forming unit that forms an image of the eye to be examined based on the detection result of the interference light;
Identifying a first reference position in the depth direction of a first B-scan for the eye to be examined based on the retinal pigment epithelial layer in the image formed by the image forming unit, and using the first reference position as a reference. an analysis unit that specifies a second reference position in the depth direction of a second B-scan for the eye to be examined according to the refractive power of the eye to be examined;
When performing a plurality of B-scans including the first B-scan and the second B-scan for the scan range of the eye to be examined, an image based on the detection result of the interference light is located at the first reference position. The first B -scan is executed for the scan range of the eye to be examined by controlling the interference optical system and changing the optical path length difference so that the image is located at the second B - scan. a control unit that controls the interference optical system to be placed at a reference position and changes the optical path length difference to execute the second B-scan for the scan range of the eye to be examined;
ophthalmological equipment including; The analysis unit sets the second reference position at a position shifted by a first shift value with respect to the first reference position when the eye to be examined is a highly myopic eye, and sets the second reference position to a position shifted by a first shift value with respect to the first reference position when the eye to be examined is not a highly myopic eye. The ophthalmologic apparatus according to claim 1, wherein the second reference position is set at a position shifted by a second shift value smaller than the first shift value with respect to the second reference position.

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