JP2022171788A - Ophthalmologic apparatus and control method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new technique for reducing a burden on an examiner or a subject when performing OCT measurement.

SOLUTION: An ophthalmologic apparatus includes an interference optical system, an operation section, a reference position acquisition section, and a control section. The interference optical system is configured to change an optical path length difference between a measurement optical path and a reference optical path, applies the measurement light via the measurement optical path to a subject's eye, and detects interference light between return light from the subject's eye and the reference light via the reference optical path. The operation section is used for specifying a first reference position in a depth direction with respect to a first B-scan out of the plurality of B-scans for the subject's eye. The reference position acquisition section acquires a reference position with respect to the remaining B-scans out of the plurality of B-scans on the basis of the first reference position. The control section changes the optical path length difference in each B-scan so that an image based on a detection result of the interference light is arranged at the first reference position or the reference position acquired by the reference position acquisition section, so as to execute a plurality of B-scans for the subject's eye.

SELECTED DRAWING: Figure 7

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to an ophthalmic apparatus and its control method.

In recent years, OCT (Optical Coherence Tomography), which utilizes the interference of light to image the surface and internal forms of an object, has attracted attention. Since OCT is not invasive to the human body like X-ray CT, it is expected to be developed particularly in the medical and biological fields. For example, in the field of ophthalmology, devices for imaging the fundus and cornea have been put to practical use.

In an ophthalmologic 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 region of interest of the subject's eye is rendered at a suitable position in the imaging range of the OCT measurement.

For example, Patent Literature 1 discloses an ophthalmologic apparatus that performs automatic processing (Auto Z) for searching for a suitable optical path length difference so that a region of interest is rendered in an imaging range by OCT measurement. In this ophthalmologic apparatus, by executing automatic processing (Z lock) that maintains a suitable rendering position obtained by Auto-Z, the region of interest is rendered at a predetermined z position (depth position) within the imaging range. Control of the optical path length difference is performed so that the state of being present is maintained.

JP 2016-041221 A

However, in the prior art the z-position is fixed which is maintained with a z-lock. As a result, when the measurement range of OCT measurement widens in the xy direction or deepens in the z direction, the target site may appear at the edge of the imaging range or deviate from the imaging range depending on the curvature of the eyeball.

In particular, when performing OCT measurement over a wide range for a highly myopic eye, the imaging range may be discontinued at the upper or lower end, or the display may be folded back. Therefore, the examiner needs to keep watching the state of the OCT measurement, which increases the burden on the examiner who performs the OCT measurement. Alternatively, it is necessary to check the measurement result and perform re-measurement if necessary, which increases the burden on the subject who undergoes OCT measurement.

The present invention has been made in view of such circumstances, and its object is to provide a new technique for reducing the burden on the examiner or subject when performing OCT measurement.

In one aspect of the embodiment, an optical path length difference between a measurement optical path and a reference optical path can be changed, light from a light source is divided into measurement light and reference light, and the measurement light that has passed through the measurement optical path is divided into an interference optical system that illuminates an eye to be inspected and detects interference light between return light from the eye to be inspected and the reference light that has passed through the reference optical path; and a first B scan among a plurality of B scans for the eye to be inspected. an operating unit for designating a first reference position in the depth direction for the B-scan, acquiring the reference position in the depth direction for at least a second B-scan among the plurality of B-scans; a reference position acquisition unit that acquires the reference position in the depth direction for the remaining B-scans of the plurality of B-scans by performing interpolation processing based on one reference position and the reference position; changing the optical path length difference by controlling the interference optical system in each B-scan so that the image based on the detection result is arranged at the first reference position or at the reference position acquired by the reference position acquisition unit; and a controller for executing the plurality of B-scans on the eye to be inspected.

Another aspect of the embodiment is configured to be able to change the optical path length difference between a measurement optical path and a reference optical path, divides light from a light source into measurement light and reference light, and converts the measurement light that has passed through the measurement optical path into measurement light and reference light. an interference optical system that irradiates an eye to be inspected and detects interference light between the return light from the eye to be inspected and the reference light that has passed through the reference optical path; and an operation unit for designating a first reference position in the depth direction. A control method for an ophthalmologic apparatus acquires a reference position in the depth direction for a second B-scan among the plurality of B-scans, and performs interpolation processing based on the first reference position and the reference position. a reference position acquiring step of acquiring the reference position in the depth direction for the remaining B-scans of the plurality of B-scans; A plurality of B-scans are performed on the subject eye by controlling the interference optical system and changing the optical path length difference in each B-scan so that the eye is located at the reference position obtained in the position obtaining step. and a control step to cause

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

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; FIG. FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; FIG. 3 is a schematic diagram for explaining processing executed by an ophthalmologic apparatus according to an embodiment; 4 is a flowchart showing an operation example of the ophthalmologic apparatus according to the embodiment;

Embodiments of an ophthalmologic apparatus and an ophthalmologic apparatus control method according to the present invention will be described in detail with reference to the drawings. It should be noted that the descriptions of the documents cited in this specification and any known techniques can be incorporated into the following embodiments.

An ophthalmologic apparatus according to an embodiment can form a tomographic image, a front image, and a three-dimensional image of an eye to be examined using OCT. In this specification, images obtained by OCT may be collectively referred to as OCT images. Also, the measurement operation for forming an OCT image is sometimes called OCT measurement.

An ophthalmic device according to some embodiments includes any one or more of an ophthalmic imaging device, an ophthalmic measurement device, and an ophthalmic treatment device. The ophthalmic imaging device included in the ophthalmic device of some embodiments is, for example, any one or more of a fundus camera, a scanning laser ophthalmoscope, a slit lamp ophthalmoscope, a surgical microscope, or the like. Also, ophthalmic measurement devices included in ophthalmic devices of some embodiments include, for example, any one or more of an eye refraction tester, a tonometer, a specular microscope, a wavefront analyzer, a perimeter, a microperimeter, and the like. is. Also, the ophthalmic treatment device included in the ophthalmic device of some embodiments is, for example, any one or more of a laser treatment device, a surgical device, a surgical microscope, and the like.

An ophthalmologic 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, amphas OCT, etc.) may be applied. It is also possible to incorporate the configuration according to the following embodiments into a single OCT apparatus.

In the following, a case of acquiring an image of the fundus will be described in detail, but the part of the eye to be photographed is not limited to the fundus. 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. Moreover, 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 adopt a configuration in which an attachment (objective lens, front lens, etc.) for photographing the anterior segment is added to the device for photographing the fundus to be 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 retinal camera unit 2 is provided with an optical system and a mechanism for acquiring a front image of the eye E to be examined. The OCT unit 100 is provided with a part of an optical system and a mechanism for performing OCT. Another part of the optical system and mechanism for performing OCT is provided in the fundus camera unit 2 . The arithmetic control unit 200 includes one or more processors that perform various arithmetic operations and controls. In addition to these, arbitrary elements such as a member for supporting the subject's face (chin rest, forehead rest, etc.) and a lens unit for switching the target part of OCT (for example, attachment for anterior segment OCT) or unit may be provided in the ophthalmologic apparatus 1 .

In this specification, the "processor" includes, 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) Programmable Logic Device), FPGA (Field Programmable Gate Array)) or the like. The processor implements the functions according to the embodiment by, for example, reading and executing a program stored in a storage circuit or 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 oculi Ef (referred to as a fundus image, fundus photograph, etc.) is a front image such as an observed image or a photographed image. Observation images are obtained by moving image shooting using near-infrared light. A photographed image is a still image using flash light. Furthermore, the fundus camera unit 2 can photograph the anterior segment Ea of the subject's eye E to acquire a front image (anterior segment image).

The fundus camera unit 2 includes an illumination optical system 10 and an imaging optical system 30 . The illumination optical system 10 irradiates the eye E to be inspected with illumination light. The imaging optical system 30 detects 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 subject's eye E through the optical path in the retinal camera unit 2, and its return light is guided to the OCT unit 100 through the same optical path.

Light (observation illumination light) output from an observation light source 11 of an illumination optical system 10 is reflected by a reflecting mirror 12 having a curved reflecting surface, passes through a condenser lens 13, and passes through a visible light cut filter 14. It becomes near-infrared light. Furthermore, the observation illumination light is once converged near the photographing light source 15 , reflected by the mirror 16 , and passed through the relay lenses 17 and 18 , the diaphragm 19 and the relay lens 20 . Then, the observation illumination light is reflected by the periphery of the perforated mirror 21 (area around the perforation), passes through the dichroic mirror 46, is refracted by the objective lens 22, Illuminate part Ea). 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 apertured mirror 21, and passes through the dichroic mirror 55. . The return light transmitted through the dichroic mirror 55 passes through the imaging focusing lens 31 and is reflected by the mirror 32 . Further, this return light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light receiving surface of the image sensor 35 by the condenser lens . The image sensor 35 detects returned light at a predetermined frame rate. The focus of the imaging optical system 30 is adjusted so as to match the fundus oculi Ef or the anterior segment Ea.

The light (imaging illumination light) output from the imaging light source 15 irradiates the fundus oculi Ef through the same path as the observation illumination light. The return light of the imaging illumination light from the subject's 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 , 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 visual acuity measurement target. A part of the light beam output from the LCD 39 is reflected by the half mirror 33A, reflected by the mirror 32, passes through the focusing lens 31 and the dichroic mirror 55, and passes through the aperture of the apertured mirror 21. The luminous flux that has passed through the aperture of the perforated mirror 21 is transmitted through the dichroic mirror 46, refracted by the objective lens 22, and projected onto the fundus oculi Ef.

By changing the display position of the fixation target on the screen of the LCD 39, the fixation position of the subject's eye E can be changed. Examples of fixation positions include the fixation position for acquiring an image centered on the macula, the fixation position for acquiring an image centered on the optic disc, and the center of the fundus between the macula and the optic disc. and a fixation position for acquiring an image of a site far away from the macula (eye fundus periphery). The ophthalmologic apparatus 1 according to some embodiments includes a GUI (Graphical User Interface) or the like for designating at least one of such fixation positions. The ophthalmologic apparatus 1 according to some embodiments includes a GUI or the like for manually moving the fixation position (the display position of the fixation target).

The configuration for presenting a movable fixation target to the subject's eye E is not limited to a display device such as an LCD. For example, a movable fixation target can be generated by selectively lighting multiple light sources in a light source array (such as a light emitting diode (LED) array). Also, one or more movable light sources can generate a movable fixation target.

Also, the ophthalmologic apparatus 1 may be provided with one or more external fixation light sources. One of the one or more external fixation light sources can project a fixation light onto the fellow eye of the eye E to be examined. The projection position of the fixation light in the fellow eye can be changed. By changing the projection position of the fixation light with respect to the fellow eye, the fixation position of the subject's eye E can be changed. The fixation position by the external fixation light source may be the same as the fixation position of the subject's eye E using the LCD 39 . For example, a movable fixation target can be generated by selectively lighting a plurality of external fixation light sources. Also, one or more movable external fixation light sources can generate a movable fixation target.

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. 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 aperture of the apertured mirror 21 . The light passing through the hole of the perforated mirror 21 is transmitted through the dichroic mirror 46 and projected onto the subject's 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 automatic 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 of the eye E to be examined. The focus optical system 60 is moved along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with the movement of the imaging focusing lens 31 along the optical path (illumination optical path) of the imaging optical system 30 . The reflecting bar 67 can be inserted into and removed from the illumination optical path. When performing focus adjustment, the reflecting surface of the reflecting bar 67 is arranged at an angle in the illumination optical path. Focus light output from the LED 61 passes through a relay lens 62, is split into two light beams by a split index plate 63, passes through a two-hole diaphragm 64, is reflected by a mirror 65, and is reflected by a condenser lens 66 onto a reflecting rod 67. is once imaged on the reflective surface of , and then reflected. Further, the focused light passes through the relay lens 20, is reflected by the perforated mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus oculi 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 and autofocus can be performed based on the received light image (split index image).

The dichroic mirror 46 synthesizes the fundus imaging optical path and the OCT optical path. The dichroic mirror 46 reflects light in the wavelength band used for OCT and transmits light for fundus imaging. The optical path for OCT (the optical path of the measurement light) includes, in order from the OCT unit 100 side toward 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 optical path for OCT. This change in optical path length is used for optical path length correction according to the axial length of the eye, adjustment of the state of interference, and the like. The optical path length changing section 41 includes a corner cube and a mechanism for moving it.

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 galvanometer 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 focus 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 a function of dividing light from a wavelength tunable light source (wavelength swept light source) into measurement light and reference light, return light of the measurement light from the subject's eye E, and reference light passing through the reference light path. and a function of generating interference light and a function of detecting this interference light. A 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 control unit 200 .

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

The reference light LR is guided to the collimator 111 by the optical fiber 110 and converted into a parallel beam, and guided to the corner cube 114 via the optical path length correction member 112 and the 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 incident direction 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 by the collimator 116 from a parallel beam to a converged beam, and enters the optical fiber 117 . The reference light LR incident on the optical fiber 117 is guided to the polarization controller 118 to have its polarization state adjusted, guided to the attenuator 120 via the optical fiber 119 to have its light amount adjusted, and guided to the fiber coupler 122 via the optical fiber 121 . be killed.

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 the optical path length changing unit 41, the optical scanner 42, the OCT focusing lens 43, and the mirror 44. and relay lens 45 . The measurement light LS that has passed 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 subject's eye E travels in the opposite direction along the same path as the forward path, is guided to the fiber coupler 105 , and reaches the fiber coupler 122 via the optical fiber 128 .

The fiber coupler 122 combines (interferences) the measurement light LS that has entered via the optical fiber 128 and the reference light LR that has entered via the optical fiber 121 to generate interference light. The fiber coupler 122 generates a pair of interference lights LC by splitting the interference lights at a predetermined splitting ratio (for example, 1:1). A pair of interference lights LC are guided to detector 125 through optical fibers 123 and 124, respectively.

Detector 125 is, for example, a balanced photodiode. A 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 .

A clock KC is supplied from the light source unit 101 to the DAQ 130 . 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 wavelength tunable light source. The light source unit 101, for example, 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. DAQ 130 sends the sampling result of the detection signal from detector 125 to arithmetic control unit 200 .

In this example, an optical path length changing unit 41 for changing the length of the optical path (measurement optical path, measurement arm) of the measurement light LS and an optical path length changing unit 41 for changing the length of the optical path (reference optical path, reference arm) of the reference light LR corner cubes 114 are provided. However, only one of the optical path length changing portion 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 by using optical members other than these.

[Arithmetic control unit]
The arithmetic control unit 200 analyzes the detection signal input from the DAQ 130 and forms an OCT image of the fundus oculi Ef. Arithmetic processing therefor is similar to that of the conventional swept source type OCT apparatus.

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

As the control of the retinal 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, the operation control of the LCD 39, the movement control of the photographing focusing lens 31, and the OCT focusing lens 43. Movement control, movement control of the reflecting rod 67, movement control of the focus optical system 60, movement control of the optical path length changing unit 41, operation control of the optical scanner 42, and the like are performed.

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

The arithmetic control unit 200 includes, for example, a microprocessor, a RAM, a ROM, a hard disk drive, a 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 and control unit 200 may include various circuit boards, such as a circuit board for forming OCT images. The arithmetic control unit 200 may also include an operation device (input device) such as a keyboard and mouse, and a display device such as an LCD.

The retinal camera unit 2, the display device 3, the OCT unit 100, and the 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

[Control system]
3 and 4 show configuration examples of the control system of the ophthalmologic apparatus 1. FIG. 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 part)
The control unit 210 executes various controls. Control unit 210 includes main control unit 211 and storage unit 212 .

(main controller)
The main controller 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 retinal camera unit 2, the optical scanner 42, the imaging focus lens 31 (focus drive unit 31A), the focus optical system 60, and the OCT focus lens 43 (focus drive unit 43A), image sensors 35 and 38, LCD 39, the entire optical system (moving mechanism 150), and the like. Further, the main control section 211 controls the light source unit 101 of the OCT unit 100, the corner cube 114 (reference driving section 114A), the attenuator 120, the polarization controllers 103 and 118, the detector 125, the DAQ 130, and the like.

For example, the main control unit 211 displays the fixation target at a position on the screen of the LCD 39 corresponding to the fixation position set manually or automatically. Further, the main control unit 211 can change (continuously or stepwise) the display position of the fixation target displayed on the LCD 39 . 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 setting is performed using, for example, a GUI. Automatic setting is performed by the data processing unit 230, for example.

The focus driver 31A moves the photographic focusing lens 31 in the optical axis direction of the photographic optical system 30 and moves the focus optical system 60 in the optical axis direction of the illumination optical system 10 . Thereby, the focus position of the imaging optical system 300 is changed. The focus driving section 31A may have a mechanism for moving the photographing 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 focus driver 43A moves the OCT focus lens 43 in the optical axis direction of the measurement optical path. Thereby, the focus position of the measurement light LS is changed. The focus 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, for example, three-dimensionally moves at least the retinal camera unit 2 (optical system). In a typical example, the movement mechanism 150 includes at least a mechanism for moving the retinal camera unit 2 in the x direction (horizontal direction), a mechanism for moving it in the y direction (vertical direction), and a mechanism for moving it in the z direction (depth direction). , back and forth). The mechanism for moving in the x-direction includes, for example, an x-stage movable in the x-direction and an x-moving mechanism for moving the x-stage. The mechanism for moving in the y-direction includes, for example, a y-stage movable in the y-direction and a y-moving mechanism for moving the y-stage. The mechanism for moving in the z-direction includes, for example, a z-stage movable in the z-direction and a z-moving mechanism for moving 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 in alignment and tracking. Tracking is to move the apparatus optical system according to the eye movement of the eye E to be examined. Alignment and focus adjustment are performed in advance when tracking is performed. Tracking is a function of maintaining a suitable positional relationship in which alignment and focus are achieved by causing the position of the apparatus optical system to follow the movement of the eyeball. Some embodiments are configured to control movement mechanism 150 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 user relatively moves the optical system and the subject's eye E by operating a user interface 240, which will be described later, so that the displacement of the subject's eye E with respect to the optical system is cancelled. For example, the main control unit 211 controls the moving mechanism 150 by outputting a control signal corresponding to the operation content of the user interface 240 to the moving mechanism 150 to move the optical system and the subject's eye E relative to each other.

In the case of auto-alignment, the main control unit 211 controls the movement mechanism 150 so that the displacement of the eye E to be examined with respect to the optical system is canceled, thereby relatively moving the optical system and the eye E to be examined. In some embodiments, the main controller 211 outputs a control signal such 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 from the eye E to be examined is a predetermined working distance. to the moving mechanism 150 to control the moving mechanism 150 to relatively move the optical system and the eye E to be examined. Here, the working distance is a default value also called a working distance of the objective lens 22, and corresponds to the distance between the subject's eye E and the optical system at the time of measurement (at the time of photographing) using the optical system.

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 controller 211 can perform a plurality of preliminary operations before performing OCT measurements. Preliminary operations include alignment, coarse focus adjustment, optical path length difference adjustment, polarization adjustment, and fine focus adjustment. A plurality of preliminary operations are performed in a predetermined order. In some embodiments, multiple preliminary operations are performed in the order described above.

Note that the types and order of preliminary operations are not limited to this, and are arbitrary. For example, a preliminary operation (small pupil determination) for determining whether or not the subject's eye E is a small pupil eye can be added to the preliminary operation. 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 processing: processing of obtaining a front image (anterior segment image) of the eye E to be examined; processing of identifying an image region corresponding to the pupil; Processing for determining the size (diameter, circumference, etc.) of the pupil region obtained; Processing for determining whether or not the eye is a small-pupil eye based on the determined size (threshold processing); Process to control. Some embodiments further include circular or elliptical approximation of the pupil region to determine the pupil size.

Rough focus adjustment is focus adjustment using the aforementioned split index. In addition, by determining the position of the photographing focusing lens 31 based on information relating 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 to be examined E, Coarse focus adjustment can also be performed.

On the other hand, fine focus adjustment is performed based on the interference sensitivity of OCT measurement. For example, by performing OCT measurement of the subject's eye E, obtaining an interference signal, and monitoring the interference intensity (interference sensitivity), the position of the OCT focusing lens 43 that maximizes the interference intensity is obtained, and Fine focus adjustment can be performed by moving the OCT focusing lens 43 .

The optical path difference adjustment is controlled so that the target portion of the eye E to be examined is rendered 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. As a target portion serving as a reference for optical path length difference adjustment, a portion exhibiting characteristic brightness in an OCT image (or a portion exhibiting characteristic reflection intensity in a reflection intensity profile) is set in advance. As a specific example, in OCT measurement of the fundus, the retinal pigment epithelium layer can be set as a reference, and in OCT measurement of the anterior segment, the corneal surface can be set as a reference. Such automatic processing for 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 imaging position achieved by Auto-Z. Such processing is called Z-lock. In the Z-lock, for example, at least one of the optical path length changing unit 41 and the reference driving unit 114A is controlled so that the target portion, which is the reference for adjusting the optical path length difference, is drawn at a predetermined z position within the frame. is controlled.

In this embodiment, a Z-lock reference position (z position) can be specified. That is, the optical path length difference is adjusted so that the target portion of the subject's eye is rendered at the specified reference position (or the Z lock position specified based on the reference position). In some embodiments, the Z-lock reference position is designated using the operation unit 240B for the OCT image displayed on the display unit 240A.

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

(storage unit)
The storage unit 212 stores various data. The data stored in the storage unit 212 includes, for example, image data of an OCT image, image data of a fundus image, information on an eye to be examined, and the like. The eye information to be examined includes information about the subject such as patient ID and name, and information about the eye to be examined such as left/right eye identification information. The storage unit 212 also 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 subject's 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), filtering, dispersion compensation, and FFT (Fast Fourier Transform). For other types of OCT devices, the imaging unit 220 performs well-known processing depending on the type.

The image forming section 220 includes, for example, the aforementioned circuit board. In this specification, "image data" and "images" based thereon may be regarded as the same.

(Data processing part)
The data processing unit 230 processes data obtained by photographing the eye E to be examined or by 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 luminance correction. Further, the data processing unit 230 performs various image processing and analysis processing on the images (eye fundus image, anterior segment image, etc.) obtained by the retinal 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 oculi Ef. Note that 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 composed 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: maximum intensity projection), etc.) on this volume data so that it can be viewed from a specific line-of-sight direction. Image data of a pseudo three-dimensional image is formed. This pseudo three-dimensional image is displayed on a display device such as the display unit 240A.

Stack data of a plurality of tomographic images can also be formed as image data of a three-dimensional image. Stacked 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. That is, stack data is image data obtained by expressing a plurality of tomographic images, which were originally defined by individual two-dimensional coordinate systems, by one three-dimensional coordinate system (that is, embedding them in one three-dimensional space). be.

The data processing unit 230 performs various renderings on the acquired three-dimensional data set (volume data, stack data, etc.) to obtain a B-mode image (longitudinal cross-sectional image, axial cross-sectional image) at an arbitrary cross section, C-mode images (cross-sectional images, horizontal cross-sectional images), projection images, shadowgrams, etc. can be formed. An arbitrary cross-sectional image, 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 portion of the 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.

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

Data processing unit 230 includes a part specifying unit 231 , a Z lock position obtaining unit 233 , and an optical path difference change amount obtaining unit 234 .

The site identification unit 231 identifies a predetermined site of the subject's eye E by analyzing the detection result of the interference light obtained by the OCT unit 100, and identifies the z position (depth position) of the identified site. In this embodiment, the site identifying section 231 analyzes the OCT image formed by the image forming section 220 based on the detection result of the interference light and identifies the z-position of the predetermined site. As the predetermined site, a site having a high interference intensity in the subject's eye E is desirable. In some embodiments, the predetermined site is the retinal pigment epithelium layer in the fundus oculi Ef. In some embodiments, the predetermined site is the anterior corneal surface in the anterior segment.

The Z lock position acquisition unit 233 acquires (identifies) 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, the Z-lock positions of other B-scans are obtained based on the 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 obtains the Z lock positions (z0+Δz) and (z0−Δz) for any of the other B scans. Get at least one. The Z lock positions for the remaining B scans are specified based on the specified 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 spline curve of degree 2 or higher, or a predetermined function.

In some embodiments, Δz is a fixed value. In some embodiments, Δz is the scanning position, the scanning range, the refraction of the eye E to be examined, information indicating whether the eye to be examined E is highly myopic, an OCT image (B scan image) of the eye to be examined E, and the It is set according to at least one of the B-scan images of the subject's 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 the Z lock position acquisition unit 233 or the storage unit 212, for example. The Z lock position acquisition unit 233 acquires the Z lock position by referring to the control information.

The optical path difference change amount acquisition unit 234 specifies the change amount of 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 the auto Z or Z lock.

When performing Auto-Z, the ophthalmologic apparatus 1 controls the optical system to perform OCT measurement of the subject's eye E (for example, the fundus oculi Ef). In this OCT measurement, for example, the subject's eye E is repeatedly scanned at a predetermined frequency. That is, the OCT measurement is repeatedly performed with the same scan pattern for the eye E to which the fixation target is presented. In some embodiments, substantially the same cross-section of the subject eye E is scanned. The optical path 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 obtains an image (image of the fundus oculi Ef) based on the detection results. ) is acquired at a specific position of the frame.

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

The information acquired by the optical path difference change amount acquisition unit 234 is not limited to the change amount itself of the optical path difference (optical path length). For example, the control contents of the optical path length changing unit 41 or the reference driving unit 114A (the number of transmission pulses, etc.), information obtained during the process of acquiring this change amount (the shift amount of the image in the frame in the z direction, etc.) ), it may be information substantially equivalent to the change amount of the optical path length difference.

In some embodiments, control information in which an amount of change in the optical path length difference (or control information corresponding to the amount of change) is associated in advance corresponding to the difference between the z-position of the predetermined portion with respect to the Z-locked position is provided in the optical path. It is stored in the length difference change amount acquisition unit 234 (or the storage unit 212). The optical path difference change amount acquisition unit 234 acquires the change amount of the optical path 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 changing unit 41 and the reference driving unit 114A based on the change amount acquired by the optical path length difference change amount acquiring unit 234 . Such auto-Z control is the same as in Japanese Patent Laid-Open No. 2016-041221, so detailed description will be omitted.

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

In some embodiments, the optical path difference change amount acquisition unit 234 obtains the difference between the Z lock position set for the immediately preceding scan and the Z lock position set for the scan, and obtains the difference. Then, the change amount of the optical path length difference corresponding to the difference is acquired. In some embodiments, the optical path length difference change amount acquisition unit 234 obtains the difference between the z position of the predetermined part identified by the part identification unit 231 and the Z lock position for each scan, and corresponds to the obtained difference. Acquires the amount of change in the optical path length difference.

The main controller 211 performs Z lock by controlling at least one of the optical path length changer 41 and the reference driver 114A based on the change amount acquired by the optical path length difference change amount acquirer 234 . Since such control of Z lock is the same as that in Japanese Patent Application Laid-Open No. 2016-041221, detailed description will be omitted.

The data processing unit 230 that functions as described above includes, for example, the aforementioned microprocessor, RAM, ROM, hard disk drive, circuit board, and the like. A storage device such as a hard disk drive pre-stores a computer program that causes a microprocessor to perform the functions described above.

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

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

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

Scan modes of the measurement light LS by the ophthalmologic apparatus 1 include, for example, horizontal scanning, vertical scanning, cross scanning, radial scanning, circular scanning, concentric scanning, and spiral scanning. These scanning modes are appropriately and selectively used in consideration of the observation site of the subject's eye E, the analysis target (retinal thickness, etc.), the time required for scanning, the precision of scanning, and the like.

The horizontal scan is to scan the scan site with the measurement light LS in the horizontal direction (x direction). Horizontal scanning also includes scanning with the measurement light LS along a plurality of horizontally extending scan lines arranged in the vertical direction (y direction). In this aspect, the spacing between scan lines can be set arbitrarily. Also, by sufficiently narrowing the interval between adjacent scan lines, the aforementioned three-dimensional image can be formed (three-dimensional scanning). The same is true for vertical scanning.

The cross scan scans the scan region with the measurement light LS along a cross-shaped trajectory consisting of two linear trajectories (linear trajectories) orthogonal to each other. A radial scan scans a scan site with the measurement light LS along a radial trajectory composed of a plurality of linear trajectories arranged at predetermined angles. Cross scanning is an example of radial scanning.

Circular scanning is to scan the scan site with the measurement light LS along a circular locus. The concentric circle scan scans the scan site with the measurement light LS along a plurality of circular trajectories concentrically arranged around a predetermined central position. A circular scan is an example of a concentric circle scan. Spiral scanning is to scan the scanning region with the measurement light LS along a helical (spiral) trajectory while gradually decreasing (or increasing) the radius of rotation.

Since the optical scanner 42 is configured to scan the scan region with the measurement light LS in directions orthogonal to each other, the measurement light LS can scan independently in the x-direction and the y-direction. Furthermore, by simultaneously controlling the directions 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. As a result, 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 spanned by the direction along the scan line (scan locus) and the fundus depth direction (z direction). In addition, especially when the interval between scan lines is narrow, the aforementioned three-dimensional image can be acquired.

The area on the subject's eye E to be scanned with the measurement light LS as described above, that is, the area on the subject's eye E to be subjected to 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. Also, the scan area in the concentric circle scan is a disk-shaped area surrounded by the trajectory of the circular scan with the maximum diameter. A scan area in radial scanning is a disk-shaped (or polygonal) region connecting both end positions of each scan line.

[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. 5 shows an example of an image displayed on the display section 240A. FIG. 5 schematically shows 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 section 211 causes the display section 240A to display a fundus image obtained by controlling the fundus camera unit 2 . The user can designate a scan area at a desired position in the fundus image displayed on the display unit 240A by performing a predetermined operation on the operation unit 240B. The main controller 211 controls the OCT unit 100 and the like to perform OCT measurement on the designated scan area. The main control unit 211 causes the image forming unit 220 to form a B-scan image based on the obtained scanning result (interference light detection result), and causes the data processing unit 230 to form a projection image using the scanning result. . The main control unit 211 causes the formed B-scan image to be displayed live in the tomographic image display area DR1. Further, the main control unit 211 causes the formed projection image to be displayed in the front image display area DR2.

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

(First designation example of Z lock position)
FIG. 6 shows a schematic diagram for explaining an example of designation of the Z lock position according to the embodiment.

For example, a front image (fundus image or projection image) FI of the fundus oculi Ef of the eye to be inspected E is scanned in a scan area SA, and a plurality of B scans B1 to BN (N is an integer equal to or greater than 2) performed within the scan area SA. are set. Assume 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 equal to or greater than 2) on the site corresponding to the set scan area SA. For convenience of explanation, it is assumed that B scan B1 to B scan BN are executed in order. The user designates a Z-lock reference position zj for one of a plurality of B-scans B1 to BN, B-scan Bj (1≤j≤N, where j is an integer). In some embodiments, the user designates the Z-lock reference position zj by performing a predetermined operation on the operation unit 240B for a tomographic image obtained by preliminary OCT temporary measurement or the like.

The main control unit 211 sets the Z lock position zj for the other B scans B1 to B(j−1) and B(j+1) to BN based on the designated Z lock reference position zj. The optical path difference change amount acquisition unit 234 acquires the change amount of the optical path difference for arranging the image of the predetermined part at the specified Z lock position zj. 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 driving unit 114A based on the acquired amount of change in each B-scan.

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

In this designation example, similarly to the first designation example, a Z-lock reference position zj is designated for a B scan Bj, which is one of the plurality of B scans B1 to BN.

The Z lock position acquisition unit 233 acquires 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 zj. Obtain the Z lock position (zj-Δz) (Δz is a positive number) (or (zj+Δz)) for The Z lock position acquisition unit 233 obtains the z lock position (zj−Δz) set for the B scan Bi, the z lock position zj set for the B scan Bj, and the z lock position (zj−Δz) set for the B scan Bk. Z lock positions for the remaining B scans are obtained by performing predetermined interpolation processing (eg, 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), B(k+1) to BN is.

That is, when the Z lock reference position zj (first reference position) is set for B scan Bj (first B scan), the reference position zj is set for B scan Bi (second B scan). A Z lock position zi (second reference position) shifted in the depth direction is set, and the Z lock position Zk is set for B scan Bk (third B scan) based on the reference position zj and Z lock position zi. (third reference position) is set.

The main control unit 211 performs other B scans B1 to B(i−1), B(i+1) to B(j−1) based on the designated Z lock reference position zj and the acquired Z lock position. , B(j+1) to B(k−1), and B(k+1) to BN. The optical path difference change amount acquisition unit 234 acquires the change amount of the optical path difference for arranging the image of the predetermined part at the designated Z lock position for 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 driving unit 114A based on the acquired amount of change in each B-scan.

As mentioned above, Δz can be a fixed value or a variable value.

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

In this designation example, Z-lock reference positions zi and zk are designated for B-scans Bi and Bk, which are any two of a plurality of B-scans B1 to BN, respectively.

The Z lock position acquisition unit 233 acquires the Z lock position zj for the B scan Bj with respect to the specified Z lock reference positions zi and zk. The Z-lock position acquisition unit 233 performs predetermined interpolation processing (eg, linear interpolation, spline interpolation) based on the z-lock position zi set for the B-scan Bi and the z-lock position zk set for the B-scan Bk. By doing so, the Z lock position zj of the B scan Bj is acquired. 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) ∼BN, get the Z lock position respectively.

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. Also, a Z lock position zj (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 performs other B scans B1 to B(i−1), B(i+1) to B(k−) based on the designated Z lock reference positions zi and zk and the acquired Z lock positions. 1), set Z lock positions for B(k+1) to BN; The optical path difference change amount acquisition unit 234 acquires the change amount of the optical path difference for arranging the image of the predetermined part at the designated Z lock position for 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 driving unit 114A based on the acquired amount of change in each B-scan.

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

In this designation example, Z-lock reference positions zi, zj, and zk are designated for B-scans Bi, Bj, and Bk, which are any three of a plurality of B-scans B1 to BN, respectively. For example, when a plurality of sequentially executed B-scans B1 to BN are divided into the first half, the middle half, and the second half, the Z-lock reference position zi is specified for the B-scan Bi to be executed in the first half, and A Z-lock reference position zj is designated for the B-scan Bj to be executed later, and a Z-lock reference position zk is designated for the B-scan Bk to be executed later.

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

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

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

The main control unit 211 performs other B scans B1 to B(i−1), B(i+1) to B based on the designated Z lock reference positions zi, zj, and zk and the acquired Z lock positions. (j−1), B(j+1) to B(k−1), B(k+1) to BN to set the Z lock position. The optical path difference change amount acquisition unit 234 acquires the change amount of the optical path difference for arranging the image of the predetermined part at the designated Z lock position for 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 driving unit 114A based on the acquired amount of change in each B-scan.

(others)
In some embodiments, the above Δz, Δz1, and Δz2 are, as described above, the scanning position, the scanning range, the refractive index of the eye to be examined E, information indicating whether the eye to be examined E is highly myopic, the eye to be examined E and a B-scan image of the subject's eye E obtained by a B-scan in a direction intersecting the B-scan.

The ophthalmologic apparatus 1 according to the embodiment provides 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 subject's eye E is completed, thereby collecting scan data in a wider range. It is possible to

10 to 12 show examples of scan ranges that can be set by the ophthalmologic apparatus 1 according to the embodiment.

In FIG. 10, scan areas SC1 to SC4 are set so as to include the scan center position O with respect to the scan area SC0 defined by the scan center position O after completion of alignment. Each scan area is arranged such that its peripheral region overlaps the peripheral region of an adjacent scan area. In some embodiments, the scan area sizes of scan areas SC0-SC5 are the same.

In FIG. 11, scan areas SC1 to SC4 are set so that peripheral regions 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. 12, similarly to FIG. 11, scan areas SC1 to SC4 are set so that peripheral regions of scan area SC0 defined by scan center position O after completion of alignment overlap. The peripheral area on the right side of scan area SC3 is arranged so as to overlap the peripheral areas on the left sides 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 areas on the right side of scan areas SC2 and SC4. In some embodiments, the scan area sizes of scan areas SC0, SC2, SC4 are the same, the scan area sizes of scan areas SC1, SC3 are the same, and the size of scan area SC1 is the size of scan area SC0. greater than

In some embodiments, Δz, Δz1, and Δz2 are predetermined corresponding to the positions of the scan areas (scan position, imaging position, imaging region) shown in FIGS. 10 to 12 .

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

In some embodiments, Δz, Δz1, Δz2 for setting the Z lock position for B scan in any of scan areas SC1 to SC4 is a representative position 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 B-scans in any of scan areas SC1-SC4 are the values of ophthalmic device 1 for scanning scan areas SC1-SC4. It is set according to control information. Examples of the control information include control information for the LCD 39 for changing the fixation position for scanning the scan areas SC1 to SC4, and control information for controlling the optical scanner 42 for scanning the scan areas SC1 to SC4. There is

FIG. 13 shows another example of a scan range that can be set by the ophthalmologic apparatus 1 according to the embodiment.

In FIG. 13, a scan area SC1 is set so as to include the scan center position O with respect to the scan area SC0 defined by the scan center position O after completion of alignment. The size of scan area SC1 is larger than the size of scan area SC0.

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

In some embodiments, Δz, Δz1, and Δz2 for setting the Z lock position for B scan in scan area SC1 are the size of scan area SC1 (3 dimensional scan range). In FIG. 12, similarly, Δz, Δz1, and Δz2 for setting the Z lock position for B scan in scan area SC1 (SC3) are the size of scan area SC0 (three-dimensional scan range). It is set according to the size (three-dimensional scan range) of (SC3).

In some embodiments, Δz, Δz1, and Δz2 are determined in advance according to information on the eye E to be examined. The information of the eye E to be examined includes, for example, a reflex measurement result (refractive index) obtained by reflex measurement separately performed on the eye E to be examined, information indicating whether or not the eye E to be examined is highly myopic, and the like. be. That is, for B scans other than the B scan for which the Z lock reference position z0 is set, the Z lock position is set at a position shifted by the first shift value with respect to the reference position z0 when the subject's eye E is highly myopic. When the subject's eye E is not severely myopic, the Z lock position is set by shifting the reference position z0 by a second shift value smaller than the first shift value. In some embodiments, information indicating whether the eye E to be examined is highly myopic or not is included in the eye information to be examined.

In some embodiments, Δz, Δz1, Δz2 above are obtained based on standard data statistically derived from measurements 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. is set to A plurality of shift values may be predetermined based on the above standard data.

In some embodiments, Δz, Δz1, and Δz2 are predetermined according to the analysis results of the 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, and a B-scan image of the eye to be examined E obtained by a B-scan in a direction intersecting the B-scan. and so on. That is, in some embodiments, the Z lock position is set based on the image based on the detection result of the interference light obtained by OCT measurement for the B scan other than the B scan for which the Z lock reference position z0 is set. be done. Further, in some embodiments, for B scans other than the B scan in which the Z lock reference position z0 is set, by scanning in the direction intersecting the scanning direction of the B scan in which the Z lock reference position z0 is set It is set based on the obtained detection result of the interference light. Horizontal scan, vertical scan, cross scan, radial scan, circular scan, concentric circle scan, helical (spiral) scan, etc. are used as the scanning mode of the B scan in the direction intersecting the B scan, for example.

[motion]
The operation of the ophthalmologic apparatus 1 according to the embodiment will be described.

FIG. 14 shows a flowchart of an operation example of the ophthalmologic apparatus 1 according to the embodiment.

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

(S2: Alignment)
The main controller 211 executes alignment. That is, the main controller 211 controls the alignment optical system 50 to project the alignment index onto the eye E to be inspected. At this time, the 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, for example, the amount of movement of the optical system specified based on the received light image acquired by the image sensor 35, and moves the optical system to the subject's eye E by the amount of movement. Move relatively. The main control unit 211 causes this process to be repeatedly executed.

(S3: focus)
After completing the alignment, the main control unit 211 starts focus adjustment. For example, the main control unit 211 starts obtaining a front image of the fundus oculi Ef and controls the focus optical system 60 to project the split index onto the fundus oculi Ef. The main control unit 211 controls the focus driving unit 31A based on the movement amount 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 movement amount. Let Here, the main control unit 211 controls the focus drive unit 43A to move the OCT focus lens 43 by the movement amount. The main control unit 211 causes this process to be repeatedly executed.

In some embodiments, multiple preliminary actions 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 controller 211 starts OCT measurement. In this OCT measurement, substantially the same section of the subject's eye E (for example, the fundus oculi Ef) is repeatedly scanned at a predetermined frequency. Subsequently, 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: Specify the Z lock reference position)
Subsequently, the main control unit 211 receives the specification of the Z-lock reference position performed by the user on the operation unit 240B.

(S6: Get Z lock position)
The main control unit 211 causes the Z lock position acquisition unit 233 to acquire the Z lock position for another B scan as described above, based on the Z lock reference position specified in step S5.

(S7: 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 difference based on the Z lock position acquired in step S6. After that, 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 acquired change amount of the optical path length difference.

(S8: Scan)
The main control unit 211 controls the optical scanner 42 to deflect the measurement light LS, and performs a B scan on the eye E to be examined.

(S9: Form a tomogram)
The main control unit 211 causes the image forming unit 220 to form a tomographic image based on the scanning result obtained in step S8.

(S10: display)
The main control unit 211 displays the tomographic image formed in step S9 in the tomographic image display area DR1 of the display unit 240A.

(S11: next?)
The main control unit 211 determines whether or not to execute the next B scan. The main control unit 211 determines whether or not to execute the next B-scan based on the scan area set in step S1 or the details of the operation performed on the operation unit 240B.

When it is determined that the next B scan is to be performed (S11: Y), the operation of the ophthalmologic apparatus 1 proceeds to step S7. When it is determined not to execute the next B-scan (S11: N), the operation of the ophthalmologic apparatus 1 proceeds to step S12.

(S12: Form front image)
When it is determined in step S11 that the next B-scan is not to be executed (S11: N), the main control unit 211 forms a projection image in the data processing unit 230 based on the scan data of the scan area set in step S1. Let

(S13: display)
Subsequently, main controller 211 causes the projection image formed in step S12 to be displayed in front image display area DR2 of display 240A. With this, the operation of the ophthalmologic apparatus 1 is completed (end).

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

Some embodiments are an ophthalmic device (1) that includes an interferometric optical system (the optical system included in the OCT unit 100), an operating section (240B), and a control section (210). 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 divides light (L0) from a light source (light source unit 101) into measurement light (LS) and reference light (LR), and irradiates the subject's eye (E) with the measurement light that has passed through the measurement light path. , the interference light (LC) between the return light from the subject's eye and the reference light passing through the reference optical path is detected. The control unit is used to designate a depth-direction reference position (Z-lock reference position) for the B-scan of the subject's eye. The control unit performs a plurality of B-scans on the eye to be examined by controlling the interference optical system and changing the optical path length difference in each B-scan so that an image based on the detection result of the interference light is arranged at the reference position. to run.

In such a configuration, a reference position in the depth direction is specified for the B scan to be performed on the eye to be examined, and the image based on the detection result of the interference light is arranged on the reference position for the eye to be examined. to execute a plurality of B-scans. As a result, even if the measurement range by OCT measurement is widened in the xy direction and deepened in the z direction, the target site may be drawn at the edge of the imaging range or deviate from the imaging range depending on the curvature of the eyeball. You will be able to avoid the situation. As a result, it is possible to reduce the burden on the examiner and the subject 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, wherein for the first B-scan, A first reference position is set, a second reference position is set using the operation unit for the second B-scan, and the first reference position and the second reference position are set for the third B-scan. A third reference position is set based on the specified position. The controller controls the interference optical system to execute the first B-scan, the second B-scan, and the third B-scan.

With such a configuration, since at least two reference positions can be designated, the region of interest may be drawn at the edge of the imaging range or deviate from the imaging range depending on the curvature of the eyeball. You can easily avoid the situation. As a result, it is possible to reduce the burden on the examiner and the subject 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, wherein for the first B-scan, A first reference position is set, for a second B-scan a second reference position shifted in the depth direction with respect to the first reference position is set, and for a third B-scan the first reference position and the second reference position are set. The controller controls the interference optical system to execute the first B-scan, the second B-scan, and the third B-scan.

With such a configuration, since at least two reference positions can be designated, the region of interest may be drawn at the edge of the imaging range or deviate from the imaging range depending on the curvature of the eyeball. You can easily avoid the situation. As a result, it is possible to reduce the burden on the examiner and the subject when performing OCT measurement.

In some embodiments, the second reference position is set 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 scanning position. Therefore, even when the measurement range is widened or the degree of curvature of the eyeball is large, as in severe myopia, the region of interest is imaged. It is possible to avoid situations in which the image is drawn at the edge of the imaging range or is out of the imaging range.

In some embodiments, the second reference position is set according to a three-dimensional scan range including the second B-scan relative to a three-dimensional scan range including the first B-scan.

With such a configuration, the Z-lock position is set according to the scanning range. Therefore, even when the measurement range is widened or when the degree of curvature of the eyeball is large, such as in severe myopia, the site of interest can be viewed as an image. It is possible to avoid situations in which the image is drawn at the edge of the imaging range or is out of the imaging range.

In some embodiments, the second reference position is set according to the refractive power of the subject's eye.

With such a configuration, the Z lock position is set according to the refractive power of the subject's eye. It is possible to avoid situations in which the site is drawn at the edge of the imaging range or is out of the imaging range.

In some embodiments, the second reference position is set at a position shifted by a first shift value with respect to the first reference position when the subject's eye is highly myopic, and is set to the first reference position when the subject's eye is not highly myopic. It is set at a position shifted by a second shift value smaller than the first shift value with respect to the reference position.

According to such a configuration, since the Z lock position is set according to the information indicating whether or not the subject's eye is highly myopic, the measurement range can be widened, and the degree of curvature of the eyeball can be increased as in severely myopic eyes. Even if the target area becomes large, it is possible to avoid situations in which the site of interest is rendered at the edge of the imaging range or is out of the imaging range.

In some embodiments, the second reference position is set to shift relative to the first reference position by a shift value selected from a plurality of predetermined shift values.

According to such a configuration, the Z lock position is set using a shift value selected from a plurality of predetermined shift values. Even if the degree of curvature increases, it is possible to easily avoid situations in which the site of interest is drawn at the edge of the imaging range or is out of the imaging range.

In some embodiments, the second reference position is set based on an image based on the detection result of interference light.

According to such a configuration, since the Z lock position is set based on the image based on the detection result of the interference light, it is possible to prevent the site of interest from appearing at the edge of the imaging range or deviating from the imaging range. easier to guess. As a result, even if the measurement range is widened or the degree of curvature of the eyeball is increased, as in severe myopia, the region of interest will not be drawn at the edge of the imaging range or will be outside the imaging range. can be avoided.

In some embodiments, the second reference position is set 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, since the Z lock position is set based on the detection result of the interference light obtained by scanning in the direction intersecting the scanning direction of the first B-scan, the region of interest is within the imaging range. It becomes easier to guess the situation where the image is drawn at the edge or is out of the imaging range. As a result, even if the measurement range is widened or the degree of curvature of the eyeball is increased, as in severe myopia, the region of interest will not be drawn at the edge of the imaging range or will be outside the imaging range. can be avoided.

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

According to such a configuration, even when the specified reference position is used for the third B-scan, the region of interest is prevented from being rendered at the edge of the imaging range or deviating from the imaging range. becomes easier.

Some embodiments are methods of controlling an ophthalmic apparatus (1) including an interference optical system (an optical system included in the OCT unit 100) and an operation section (240B). 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 divides light (L0) from a light source (light source unit 101) into measurement light (LS) and reference light (LR), and irradiates the subject's eye (E) with the measurement light that has passed through the measurement light path. , the interference light (LC) between the return light from the subject's eye and the reference light passing through the reference optical path is detected. The operation unit is used to designate a reference position in the depth direction for the B-scan of the eye to be examined. A control method for an ophthalmologic apparatus includes a reference position setting step of setting a reference position designated by an operation unit for a plurality of B-scans of an eye to be inspected, and an image based on a detection result of interference light being arranged at the reference position. and a control step of executing a plurality of B-scans on the subject's eye by controlling the interference optical system and changing the optical path length difference in each B-scan so as to perform a plurality of B-scans.

According to such control, even if the measurement range of OCT measurement is widened in the xy direction or deepened in the z direction, the site of interest may be rendered at the edge of the imaging range or the image may be drawn depending on the curvature of the eyeball. It will be possible to avoid situations such as deviating from the normalization range. As a result, it is possible to reduce the burden on the examiner and the subject when performing OCT measurement.

In some embodiments, the reference position setting step includes, for the first B-scan, setting the specified first reference position using the operation unit; setting a second reference position specified using the part; and setting a third reference position identified based on the first reference position and the second reference position for a third B-scan. and the controlling step causes the first B-scan, the second B-scan, and the third B-scan to be performed by controlling the interference optical system.

According to such control, since at least two reference positions can be specified, the site of interest may be drawn at the edge of the imaging range or deviate from the imaging range depending on the curvature of the eyeball. You can easily avoid the situation. As a result, it is possible to reduce the burden on the examiner and the subject when performing OCT measurement.

In some embodiments, the reference position setting step includes setting a first reference position specified using the operation unit for the first B-scan, and setting a first reference position for the second B-scan. setting a second reference position shifted in the depth direction with respect to the one reference position; and a third reference position identified based on the first reference position and the second reference position for a third B-scan. and the controlling step causes the first B-scan, the second B-scan, and the third B-scan to be performed by controlling the interference optical system.

According to such control, since at least two reference positions can be specified, the site of interest may be drawn at the edge of the imaging range or deviate from the imaging range depending on the curvature of the eyeball. You can easily avoid the situation. As a result, it is possible to reduce the burden on the examiner and the subject when performing OCT measurement.

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

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

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

1 ophthalmologic apparatus 2 retinal camera unit 10 illumination optical system 30 imaging optical system 31 imaging focusing lens 41 optical path length changing unit 42 optical scanner 50 alignment optical system 60 focusing optical system 100 OCT unit 101 light source unit 200 arithmetic control unit 210 control unit 211 Main control unit 212 Storage unit 220 Image forming unit 230 Data processing unit 231 Part specifying 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 Measurement light LR Reference light LC Interference light

Claims (4)

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, the measurement light passed through the measurement optical path is irradiated to the subject's eye, and the subject's eye is irradiated with the measurement light. 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 operation unit for designating a first reference position in the depth direction for a first B-scan among a plurality of B-scans for the eye to be inspected;
obtaining the reference position in the depth direction for at least a second B-scan among the plurality of B-scans, and performing an interpolation process based on the first reference position and the reference position, thereby obtaining the plurality of B-scans; a reference position acquisition unit that acquires the reference position in the depth direction for the remaining B-scans;
controlling the interference optical system in each B-scan so that an image based on the detection result of the interference light is placed at the first reference position or at the reference position acquired by the reference position acquisition unit; a control unit that executes the plurality of B-scans on the eye to be inspected by changing the
ophthalmic equipment, including The reference position acquisition unit acquires a second reference position of the second B-scan shifted in the depth direction with respect to the first reference position, and based on the first reference position and the second reference position 2. The ophthalmologic apparatus according to claim 1, wherein a third reference position in the depth direction for a third B-scan is obtained by using a second B-scan. 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, the measurement light passed through the measurement optical path is irradiated to the subject's eye, and the subject's eye is irradiated with the measurement light. 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 operation unit for designating a first reference position in the depth direction for a first B-scan of a plurality of B-scans for the eye to be inspected;
A control method for an ophthalmic device comprising:
The reference position in the depth direction is obtained for a second B-scan among the plurality of B-scans, and interpolation processing is performed based on the first reference position and the reference position to obtain the plurality of B-scans. a reference position obtaining step of obtaining the reference position in the depth direction for the remaining B-scans of the scan;
controlling the interference optical system in each B scan so that an image based on the detection result of the interference light is arranged at the first reference position or at the reference position obtained in the reference position obtaining step; a control step of performing a plurality of B-scans on the eye to be inspected by changing
A method of controlling an ophthalmic device comprising: The reference position obtaining step obtains a second reference position of the second B-scan shifted in the depth direction with respect to the first reference position, and based on the first reference position and the second reference position 4. The method of controlling an ophthalmologic apparatus according to claim 3, wherein a third reference position in the depth direction for a third B-scan is acquired by using a second B-scan.

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