JP2018064662A - Ophthalmologic imaging device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow an examiner to easily check a state of the ocular fundus at a position where a tomographic image of an eye to be examined is acquired in displaying a display form (e.g., a measurement line) indicating a tomographic image acquisition position for the eye to be examined in a front image of the eye to be examined.SOLUTION: An ophthalmologic imaging device includes: display control means for displaying a display form 314a indicating an acquisition position of one two-dimensional tomographic image in an eye to be examined in a front image of the eye to be examined, and moving it according to an operation by an examiner; and tomographic image acquisition means for acquiring one two-dimensional tomographic image of the eye to be examined based on the acquisition position of the one two-dimensional tomographic image set using the display form. The display control means causes the display form to be displayed in the front image so that a region of the front image corresponding to the acquisition position of the one two-dimensional tomographic image is displayed.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an ophthalmologic photographing apparatus for photographing an eye to be examined and a control method thereof.

  An optical coherence tomography (OCT) using low-coherent light is known as an ophthalmologic imaging apparatus that can obtain a tomographic image of an eye to be examined (for example, fundus, anterior ocular segment, etc.) non-invasively. Yes. In such an ophthalmologic photographing apparatus, for example, a tomographic image is obtained by obtaining information in the depth direction of the eye to be examined using an OCT optical system while one-dimensionally scanning measurement light on the fundus.

  In addition, the above-described apparatus has a configuration in which an OCT optical system is combined with a scanning laser ophthalmoscope (SLO optical system) for acquiring a front image of an eye to be examined or an imaging optical system having a two-dimensional imaging element. It is known that the examiner changes the imaging position in the vertical and horizontal directions of the subject's eye while moving the measurement line on the front image of the subject's eye displayed on the display by a predetermined switch operation, and takes a tomographic image. The position is determined.

  However, in the case of the conventional apparatus configuration, it is difficult to observe a constant tomographic image without being affected by the movement of the eye under measurement. Therefore, Patent Document 1 discloses an ophthalmologic imaging apparatus that corrects the acquisition position of a tomographic image of an eye to be examined based on the positional deviation of the eye to be examined. At this time, in Patent Document 1, a measurement line electronically displayed on the front image in order to set a tomographic image acquisition position in the eye to be examined is moved according to the operation of the examiner, and It is disclosed that the position is corrected based on the positional deviation.

JP 2009-160190 A

  Here, the measurement line is actually displayed on the front image as a band having a certain width. For this reason, it is difficult for the examiner to confirm on the front image the state of the fundus at the position where the measurement line is displayed on the front image. That is, since it was difficult for the examiner to confirm the state of the fundus at the position where the tomographic image of the subject was acquired on the front image, it was not easy to use.

  One of the objects of the present invention is that when displaying a display form (for example, a measurement line) indicating the acquisition position of a tomographic image of the eye to be examined on the front image of the eye to be examined, the examiner acquires the tomographic image of the eye to be examined. It is possible to easily confirm the state of the fundus at the position.

One of the ophthalmologic photographing apparatuses according to the present invention is
Light splitting means for splitting light from the OCT light source into a measurement optical path and a reference optical path, scanning means for scanning measurement light irradiated on the eye to be examined through the measurement optical path, and reflection from the eye to be examined by the measurement light A tomographic image acquisition means for acquiring a tomographic image of the eye to be inspected using an OCT optical system comprising: a light receiving element for detecting light synthesized from light and light from the reference optical path;
Front image acquisition means for acquiring a front image of the eye to be examined;
The tomographic image acquired by the tomographic image acquisition and the frontal image acquired by the frontal image acquisition unit are displayed on the display as moving images, and on the frontal image to set the acquisition position of the tomographic image in the eye to be examined. Display control means for moving the measurement line electronically displayed in accordance with the operation of the examiner,
An ophthalmologic imaging apparatus that acquires a tomographic image of an eye to be examined by controlling the scanning unit based on an acquisition position of the tomographic image set using the measurement line,
The measurement line indicates an acquisition position of one two-dimensional tomographic image in the eye to be examined.
The display control unit electronically displays the measurement line on the front image so as to surround the periphery of the acquisition position of the one two-dimensional tomographic image.

One of the ophthalmologic photographing apparatuses according to the present invention is
Display control means for displaying a display form indicating an acquisition position of one two-dimensional tomographic image in the eye to be examined on a front image of the eye to be examined and moving in accordance with an operation of the examiner;
A tomographic image acquisition means for acquiring one two-dimensional tomographic image of the eye to be examined based on the acquisition position of the one two-dimensional tomographic image set using the display form;
The display control means displays the display form on the front image so that a region of the front image corresponding to the acquisition position of the one two-dimensional tomographic image is displayed.

  According to one aspect of the present invention, when displaying a display form (for example, a measurement line) indicating the acquisition position of a tomographic image of the subject's eye on the front image of the subject's eye, the examiner acquires the tomographic image of the subject's eye. It is possible to easily check the state of the fundus at the position to be pressed.

The figure which shows the structural example of the ophthalmologic imaging device which concerns on embodiment. The figure which shows the example of the operation screen which concerns on embodiment The flowchart showing an example of the automatic alignment operation | movement which concerns on embodiment. 6 is a flowchart illustrating an example of a fundus tracking operation according to the embodiment. The figure which shows an example of the measurement line shape which concerns on embodiment The figure which shows an example of the measurement line display during the fundus tracking operation concerning an embodiment

  Embodiments for carrying out the present invention will be described with reference to the drawings.

<Schematic configuration of ophthalmic imaging apparatus>
With reference to FIG. 1, a schematic configuration of an ophthalmologic imaging apparatus (optical coherence tomography apparatus) according to the present embodiment will be described. The ophthalmologic imaging apparatus acquires a tomographic image of the eye to be inspected based on interference light obtained by interfering the return light from the eye to be examined irradiated with the measurement light via the scanning unit and the reference light corresponding to the measurement light. . The ophthalmologic photographing apparatus includes an optical head unit 100, a spectroscope 200, and a control unit 300. Hereinafter, configurations of the optical head unit 100, the spectroscope 200, and the control unit 300 will be described in order.

<Configuration of Optical Head Unit 100 and Spectrometer 200>
The optical head unit 100 includes a measurement optical system for capturing a two-dimensional image (front image) and a tomographic image of the anterior eye Ea of the eye E to be examined, the fundus Er of the eye to be examined. Hereinafter, the inside of the optical head unit 100 will be described. The objective lens 101-1 is installed facing the eye E, and the optical path is separated by the first dichroic mirror 102 and the second dichroic mirror 103 which function on the optical axis and function as the optical path separation unit. . That is, the optical path branches to the measurement optical path L1, the fundus observation optical path and the fixation lamp optical path L2, and the anterior eye observation optical path L3 of the OCT optical system for each wavelength band.

  The optical path L2 is further branched by the third dichroic mirror 118 into the optical path to the APD (avalanche photodiode) 115 for fundus observation and the fixation lamp 116 for each wavelength band. Here, 101-2, 111, and 112 are lenses, and the lens 111 is driven by a motor (not shown) for focusing adjustment for fixation lamp and fundus observation. The APD 115 has sensitivity in the wavelength of illumination light for fundus observation (not shown), specifically, around 780 nm. On the other hand, the fixation lamp 116 generates visible light to promote fixation of the subject.

  Further, in the optical path L2, an X scanner 117-1 (for the main scanning direction) for scanning light emitted from a fundus observation illumination light source (not shown) on the fundus Er of the eye E, Y scanner 117-2. (For the sub-scanning direction intersecting with the main scanning direction) is arranged. The lens 101-2 is disposed with the vicinity of the center position of the X scanner 117-1 and Y scanner 117-2 as a focal position. The X scanner 117-1 is composed of a resonance type mirror, but may be composed of a polygon mirror. The vicinity of the center position of the X scanner 117-1 and the Y scanner 117-2 and the position of the pupil of the eye E to be examined are optically conjugate. An APD (avalanche photodiode) 115 is a single detector, and detects light that is scattered and reflected from the fundus Er. The third dichroic mirror 118 is a prism on which a perforated mirror or a hollow mirror is deposited, and separates illumination light and return light from the fundus Er.

  A lens 141 and an infrared CCD 142 for observing the anterior eye are arranged in the optical path L3. The infrared CCD 142 has sensitivity at the wavelength of illumination light for anterior eye observation (not shown), specifically, around 970 nm. The optical path L1 forms an OCT optical system as described above, and is used to capture a tomographic image of the fundus oculi Er of the eye to be examined. More specifically, it is used to obtain an interference signal for forming a tomographic image.

  In the optical path L1, a lens 101-3, a mirror 121, and an X scanner 122-1 that functions as a scanning unit and a Y scanner 122-2 are arranged to scan light on the fundus Er of the eye to be examined. ing. Further, the X scanner 122-1 and the Y scanner 122-2 are arranged so that the vicinity of the center position of the X scanner 122-1 and the Y scanner 122-2 is the focal position of the lens 101-3. 1. The vicinity of the center position of the Y scanner 122-2 and the position of the pupil of the eye E to be examined have an optical conjugate relationship. With this configuration, the optical path with the scanning unit as an object point is substantially parallel between the lens 101-1 and the lens 101-3. Accordingly, even when the X scanner 122-1 and the Y scanner 122-2 perform scanning, the angles incident on the first dichroic mirror 102 and the second dichroic mirror 103 can be made the same.

  The measurement light source 130 is an OCT light source for causing measurement light to enter the measurement optical path. In the present embodiment, the measurement light source 130 is a fiber end and has an optical conjugate relationship with the fundus Er of the eye E to be examined. Reference numerals 123 and 124 denote lenses, and the lens 123 is driven by a motor (not shown) in order to adjust the focus. The focus adjustment is performed so that the light emitted from the measurement light source 130 that is the fiber end is imaged on the fundus Er. The lens 123 that functions as a focusing adjustment unit is disposed between the measurement light source 130 and the X scanner 122-1 and Y scanner 122-2 that function as scanning units. This eliminates the need to move the larger lens 101-3 or the optical fiber 125-2.

  By this focus adjustment, an image of the measurement light source 130 can be formed on the fundus Er of the eye E, and the return light from the fundus Er of the eye E can be efficiently returned to the optical fiber 125-2.

  In FIG. 1, the optical path between the X scanner 122-1 and the Y scanner 122-2 is configured in the plane of the paper, but is actually configured in the direction perpendicular to the plane of the paper. Further, the optical head unit 100 includes a head driving unit 140. The head driving unit 140 includes three motors (not shown), and the optical head unit 100, which is an example of an apparatus main body including at least an OCT optical system, is three-dimensionally (X, Y, Z) with respect to the eye E. ) It is configured to be movable in the direction. Thereby, alignment of the optical head part 100 with respect to the eye E can be performed.

  Next, the configuration of the optical path from the measurement light source 130, the reference optical system (reference optical path), and the spectrometer 200 will be described. The measurement light source 130, the optical coupler 125, the optical fibers 125-1 to 12, the lens 151, the dispersion compensation glass 152, the mirror 153, and the spectroscope 200 constitute a Michelson interference system. The optical fibers 125-1 to 12-4 are single mode optical fibers connected to and integrated with the optical coupler 125.

  The light emitted from the measurement light source 130 is split into the measurement light on the optical fiber 125-2 side and the reference light on the optical fiber 125-3 side via the optical coupler 125 through the optical fiber 125-1. Here, the optical coupler 125 is an example of a light splitting unit that splits the light emitted from the measurement light source 130 into measurement light and reference light. The measurement light is applied to the fundus Er of the eye E to be observed through the above-described OCT optical system optical path, and reaches the optical coupler 125 through the same optical path due to reflection and scattering by the retina.

  On the other hand, the reference light reaches the mirror 153 and is reflected through the optical fiber 125-3, the lens 151, and the dispersion compensation glass 152 inserted to match the dispersion of the measurement light and the reference light. Then, it returns on the same optical path and reaches the optical coupler 125. The measurement light and the reference light are combined by the optical coupler 125 to become interference light. Here, interference occurs when the optical path length of the measurement light and the optical path length of the reference light are substantially the same. The mirror 153 is held by a motor and a drive mechanism (not shown) so that the position can be adjusted in the optical axis direction, and the optical path length of the reference light can be adjusted to the optical path length of the measurement light that changes depending on the eye E. The interference light is guided to the spectrometer 200 through the optical fiber 125-4.

  The spectroscope 200 includes a lens 201, a diffraction grating 202, a lens 203, and a line sensor 204 which is an example of a light receiving element. The interference light emitted from the optical fiber 125-4 becomes substantially parallel light through the lens 201, is then dispersed by the diffraction grating 202, and is imaged on the line sensor 204 by the lens 203.

  Next, the periphery of the measurement light source 130 will be described. The measurement light source 130 is an SLD (Super Luminescent Diode) which is a typical low-coherent light source. The center wavelength is 855 nm and the wavelength bandwidth is about 100 nm. Here, the bandwidth is an important parameter because it affects the resolution of the obtained tomographic image in the optical axis direction. Further, although the SLD is selected here as the type of light source, it is only necessary to emit low-coherent light, and ASE (Amplified Spontaneous Emission) or the like can also be used. Near-infrared light is appropriate as the center wavelength in view of measuring the eye. Moreover, since the center wavelength affects the lateral resolution of the obtained tomographic image, it is desirable that the center wavelength be as short as possible. For both reasons, the center wavelength was set to 855 nm.

  In this embodiment, a Michelson interferometer is used as an interferometer, but a Mach-Zehnder interferometer may be used. It is desirable to use a Mach-Zehnder interferometer when the light amount difference is large according to the light amount difference between the measurement light and the reference light, and a Michelson interferometer when the light amount difference is relatively small.

<Configuration of Control Unit 300>
The control unit 300 is connected to each part of the optical head unit 100 and the spectroscope 200. Specifically, the control unit 300 is connected to the infrared CCD 142 in the optical head unit 100 and configured to generate an observation image of the anterior eye portion Ea of the eye E to be examined. The control unit 300 is also connected to the APD 115 in the optical head unit 100, and is configured to generate an observation image of the fundus Er of the eye E to be examined (acquisition of a front image). Further, the control unit 300 is also connected to a head driving unit 140 in the optical head unit 100, and is configured to be able to drive the optical head unit 100 with respect to the eye E to be examined three-dimensionally. On the other hand, the control unit 300 is also connected to the line sensor 204 of the spectrometer 200. Accordingly, it is possible to acquire a measurement signal wavelength-resolved by the spectroscope 200, and further, it is possible to generate a tomographic image of the eye E based on the measurement signal. The generated anterior ocular segment observation image, fundus oculi observation image (frontal image), and tomographic image of the eye E to be examined can be displayed as a moving image on the monitor 301 (display) connected to the control unit 300.

  FIG. 2 is a screen display example of the monitor 301. The control unit 300, which is an example of a display control unit, displays each acquired image of the eye E on the anterior eye part display unit 312, the fundus display unit 313, and the tomographic image display units 315 and 316. As will be described later when explaining tracking, a tomographic image measurement line 314 that can be set by the examiner is electronically superimposed on the fundus observation image (front image) as a character image in the fundus display unit 313. . In FIG. 2, the measurement line 314 is displayed as a vertical and horizontal crossing line, the tomographic image display unit 315 is a vertical measurement line, and the tomographic image display unit 316 is a tomographic image corresponding to the horizontal measurement line. Further, in FIG. 2, a mouse pointer (cursor) 311 that can be operated by the examiner, a tracking start / stop button 318, and a measurement start button 317 are displayed. Note that a slider for adjusting the focus position of the measurement light, a slider for changing the depth position of the tomographic image, and the like may be displayed on the monitor 301.

<Alignment method of eye E>
Next, an alignment method for the eye E using the ophthalmologic photographing apparatus according to the present embodiment will be described with reference to the flowchart of FIG. Prior to imaging, the examiner first seats the subject in front of the device.

  In step S101, the examiner drives an operation unit (not shown) and a motor that can be driven in a three-dimensional (X, Y, Z) direction, and the pupil of the eye E to be examined is displayed on the anterior ocular segment observation image display unit on the monitor 301. The optical head unit 100 is moved so that a part is displayed. When a part of the pupil is displayed on the display unit, the system control unit 300 starts automatic alignment by the following steps. In step S <b> 102, the control unit 300 functions as an anterior ocular segment image acquisition unit, and periodically acquires and analyzes an anterior ocular segment image from the infrared CCD 142 when automatic alignment is started. Specifically, the control unit 300 detects a pupil region in the input anterior segment image.

  In step S103, the control unit 300 calculates the center position of the detected pupil region. In step S104, the control unit 300 functions as a positional deviation amount calculation unit, and calculates a displacement amount (a positional deviation amount) between the detected center position of the pupil region and the central position of the anterior ocular segment image. The ophthalmologic photographing apparatus of the present embodiment is configured such that the center of the anterior eye image coincides with the optical axis of the objective lens 101-1, and the displacement calculated in step S104 is determined based on the eye E and the measurement optical axis. Represents the amount of misalignment.

  In step S105, the control unit 300 instructs the head driving unit 140 to move the optical head unit 100 in accordance with the positional deviation amount calculated in step S104. In step S206, the head driving unit 140 drives three motors (not shown) to move the position of the optical head unit 100 in the three-dimensional (X, Y, Z) direction with respect to the eye E. As a result of the movement, the position of the optical axis of the objective lens 101-1 mounted on the optical head unit 100 is corrected so as to approach the pupil center position of the anterior segment Ea of the eye E to be examined.

  In step S <b> 107, after the movement of the optical head unit 100, the control unit 300 acquires an anterior eye image again from the infrared CCD 142 and performs pupil detection. Here, it is determined whether or not the pupil of the eye E has been moved into a preset designated area. When it is determined that the fixation of the eye to be examined is stable and the pupil has been moved into the designated area (S107; YES), the automatic alignment process is terminated.

  On the other hand, when the eye pupil to be examined does not fit in the predetermined area (S207; NO), it is determined that the optical axis of the objective lens 101-1 mounted on the optical head unit 100 and the optical axis of the eye to be examined do not match, Returning to step S102, the above process is repeated.

  By this series of automatic alignment operations, the optical axis position of the objective lens 101-1 always moves so as to track the pupil center position of the anterior eye portion Ea of the eye E to be examined. Even if the line-of-sight direction of the eye E changes, the optical axis of the objective lens 101-1 tracks the pupil center of the anterior segment Ea after the line-of-sight change (anterior eye tracking) by this automatic alignment operation. Therefore, the measurement light beam emitted from the measurement light source 130 is applied to the fundus Er without being blocked by the pupil, and a stable tomographic image can be taken.

  This series of automatic alignment operations can be continued until scanning of the measurement light on the fundus oculi Er of the eye E is started in order to record a tomographic image of the fundus oculi Er of the eye E to be examined. is there.

  In the present embodiment, automatic alignment of the optical system with respect to the eye to be examined is performed based on the anterior ocular segment image using the infrared CCD, but this may be performed using other methods. For example, it is possible to perform automatic alignment in a three-dimensional (X, Y, Z) direction by projecting an alignment index onto the anterior segment of the eye to be examined and detecting the reflected light.

<Tomographic imaging method>
Next, a tomographic image capturing method using the ophthalmologic imaging apparatus of the present embodiment will be described.

  The control unit 300 starts an operation of acquiring a two-dimensional observation image of the fundus Er through the optical path L2 after the above-described automatic alignment operation is completed. Specifically, the control unit 300 starts obtaining reflected light from the fundus Er input from the APD 115. The reflected light from the fundus Er is continuously scanned two-dimensionally on the fundus Er by the X scanner 117-1 and the Y scanner 117-2. Therefore, by regularly synthesizing the reflected light input from the APD 115, an observation image of the fundus oculi Er can be periodically obtained. The obtained observation image is displayed on the fundus display unit 313 of FIG.

  The examiner observes the fundus oculi image Er, designates a tomographic image as a desired site, and designates a measurement site using the character image. When the measurement part is designated, the measurement start button 317 arranged on the monitor 301 is operated to start imaging. The control unit 300 starts generating a tomographic image for recording based on interference light output from the line sensor 204 periodically in accordance with an instruction to start imaging.

  Here, the interference light output from the line sensor 204 is a signal for each frequency dispersed by the diffraction grating 202. The control unit 300 performs FFT (Fast Fourier Transform) processing on the signal from the line sensor 204 to generate information in the depth direction at a certain point on the fundus Er. This information generation in the depth direction at a certain point on the fundus oculi Er is called A scan.

  The measurement light emitted to the fundus Er can be arbitrarily scanned on the fundus Er by driving and controlling at least one of the X scanner 122-1 and the Y scanner 122-2. The measurement light can be scanned on the eye to be examined by the X scanner 122-1 and the Y scanner 122-2.

  The control unit 300 generates a tomographic image at an arbitrary trajectory on the fundus Er by bundling a series of A scans acquired during a single scan along the arbitrary trajectory into a single two-dimensional image. To do.

  Further, the control unit 300 drives and controls at least one of the X scanner 122-1 and the Y scanner 122-2, thereby repeating the above-described scanning with an arbitrary locus a plurality of times. When the same locus operation is performed a plurality of times, a plurality of tomographic images in an arbitrary locus on the fundus Er can be obtained. For example, the control unit 300 drives only the X scanner 122-1, and repeatedly executes scanning in the X direction to generate a plurality of tomographic images on the same scanning line of the fundus Er. The control unit 300 can also drive the X scanner 122-1 and the Y scanner 122-2 simultaneously to repeatedly execute a circular operation, and generate a plurality of tomographic images on the same circle of the fundus Er. Then, the control unit 300 performs an averaging process on the plurality of tomographic images, thereby generating one high-quality tomographic image and displays it on the tomographic image display units 315 and 316 on the monitor 301.

  On the other hand, the control unit 300 controls the driving of at least one of the X scanner 122-1 and the Y scanner 122-2, thereby performing scanning a plurality of times while shifting the scanning according to the above-described arbitrary locus in the XY direction. You can also. For example, a plurality of tomographic images covering the entire rectangular area on the fundus Er is generated by performing scanning in the X direction a plurality of times while shifting in the Y direction at regular intervals. Then, the control unit 300 generates three-dimensional information of the fundus oculi Er by synthesizing the plurality of tomographic images and displays it on the monitor 301.

  The scanning patterns by these X scanner 122-1 and Y scanner 122-2 can be arbitrarily switched by pressing a scanning pattern selection button (not shown).

<Ocular fundus tracking method>
The tracking method of the present embodiment will be described with reference to the flowchart of FIG. 4 and the measurement line display examples of FIGS.

  As described above, in order to obtain a high-definition tomographic image, an averaging process of a plurality of tomographic images is performed. However, it is difficult to maintain the fixation state of the eye to be examined for a long time, and it is necessary to correct the measurement site according to the movement of the eye to be examined. Fundus tracking is a control method for correcting a shift of the measurement light irradiation position caused by the movement of the eye E when the measurement light is irradiated to the fundus Er of the eye E to observe the state of the eye E. It is.

  In the present embodiment, a description will be given by taking as an example a method for acquiring a two-dimensional tomographic image obtained by X-axis scanning, which is the basis for acquiring a tomographic image.

  In step S <b> 201, the examiner displays the position designation measurement line 314 a (first measurement line) superimposed on the fundus image Er on the fundus display unit 313, and selects a tomographic image portion to be acquired with the length and position. specify. Here, the first measurement line is an example of a measurement line electronically displayed on the front image so as to surround the periphery of the acquisition position of one two-dimensional tomographic image. FIG. 6A is a display example in which the examiner operates the mouse pointer 311 and designates the position designation measurement line 314a in the macular direction from the center of the nipple. Here, the measurement line for position designation 314a in FIG. 6 is a hollow display where the center of the measurement line is transparent. In general, a width of several dots is necessary to display a two-dimensional measurement line in the X-axis scanning direction in an easy-to-understand manner for the examiner. In normal line display, the fundus image of the part to be acquired is always a line. Sometimes it was hidden. Thus, by displaying the position specifying measurement line as a hollow display, it is possible to easily observe the fundus region that the examiner actually wants to acquire. Here, as a method for facilitating observation of the fundus image under the measurement line, the shape of the position specifying measurement line 314a, which is an example of the first display form, is not limited to this embodiment. As another method, for example, a point having a position corresponding to the measurement line on the fundus image is instantaneously displayed as a point, and the point moves to a position corresponding to the measurement line at a high speed, so that the tomographic image is displayed. There is a method of indicating the acquisition position. Further, for example, a frame in which the measurement line is displayed without displaying the fundus image of the subject eye and a frame in which the fundus image of the subject eye is displayed without displaying the measurement line are matched with the frame rate of the monitor 301. There is also a method of indicating the acquisition position of the tomographic image on the fundus image by alternately switching and displaying. As described above, by performing control using the optical illusion of the examiner, it is possible to observe the fundus image immediately below the line while displaying the measurement line. Further, the fundus image by the SLO optical system is displayed on the fundus display unit 313 in gray scale. Therefore, by changing the display of the portion instructed by the examiner of the fundus image from the gray scale display to a color scale display such as red or blue, it is possible to observe both the measurement position and the fundus image. Similarly, the shape of the second measurement line 314c, which is an example of a second display form to be described later, is not limited to this embodiment, and may be the shape described above.

  In the present embodiment, a single measurement line for X-axis scanning is described for the sake of simplicity, but the shape of the measurement line can be changed depending on the tomographic image to be acquired. In the case of the cross measurement line 314 shown in FIG. 2, the length and position can be individually set for each of the vertical and horizontal measurement lines. It is possible to easily observe the fundus image. Furthermore, when generating a three-dimensional map of a tomographic image, it is also possible to make the designation at the time of position setting a rectangular shape surrounding the entire desired area instead of a line shape.

  In step S202, the examiner operates the tracking start button 318 shown in FIG. 2 to instruct the start of the tracking operation. The control unit 300 starts the fundus tracking operation based on the fundus observation image acquired periodically according to the start signal from the examiner. In addition to the above button operation, tracking can be started in accordance with the end of the mouse drag operation in S201.

  Next, a measurement line display method according to this embodiment will be described. In the conventional control, the first measurement line described above follows the movement of the eye to be examined and corrects the tomographic image acquisition position. However, there is a concern that such control cannot easily determine how much the subject's eye has moved from the specified position, and it is difficult to find problems such as abnormal fixation of the subject's eye.

  Therefore, in the present embodiment, in step S203 immediately after the start of tracking, the control unit 300 displays the second measurement line 314c for tracking inside the position specifying measurement line 314a that is hollowed out. In the present embodiment, since the position specifying measurement line 314a is hollowed out as described above, the tracking measurement line 314c is displayed on the inner side in order to increase the visibility of the examiner. Further, in order to improve visibility, in step S204, the first measurement line 314a is changed to the measurement line display 314b during tracking execution. FIG. 6B illustrates the fundus image of the fundus display unit 313 and the superimposed character image at the end of steps S203 and S204.

  Here, FIG. 5 shows a summary of the character display of each measurement line.

  During the position designation, only the position designation measurement line 314a is displayed on the fundus oculi display portion 313. On the other hand, during tracking execution, two types of measurement lines are displayed: a measurement line 314b for position designation and a measurement line 314c for tracking. Further, in the present embodiment, the position designation measurement line 314b during tracking is displayed with a different character from the measurement line 314a during position designation in order to clarify the distinction from the tracking measurement line 314c. Since steps S203 and S204 are controls for improving visibility, in S203, the tracking measurement line 314c can be displayed so as to overlap the position specifying measurement line 314a. Further, step S204 may be omitted, and the same character display as that of 314a may be displayed without changing the character of the position specifying measurement line 314b during tracking.

  Next, tracking control using the measurement line will be described.

  In step S205, the control unit 300 acquires a fundus observation image serving as a reference for tracking. In step S206, the control unit 300 confirms the presence or absence of a tracking control interruption signal from the subject.

  When the interruption instruction from the examiner is not confirmed in step S206, the control unit 300 proceeds to step 207 and acquires the fundus observation image again. In step S208, the control unit 300 calculates the movement amount of the fundus oculi Er using two fundus observation images, a fundus observation image acquired previously and a current fundus observation image. Specifically, the control unit 300 calculates the amount of movement of the fundus Er in the two-dimensional (X, Y) direction by calculating the amount of displacement in the two-dimensional (X, Y) direction of the region of interest on the fundus observation image. calculate. The control unit 300 is an example of a movement amount acquisition unit that acquires the movement amount of the eye to be inspected based on a plurality of images (for example, a plurality of fundus images) of the eye to be acquired acquired at different times. Further, the region of interest is the macular of the fundus, the optic disc, the branch of the blood vessel, etc., and any region on the fundus can be used as long as the movement amount of the fundus can be calculated.

  In step S209, the control unit 300 changes the display position of the second measurement line 314c according to the calculated movement amount of the fundus Er. That is, the second measurement line 314c during tracking control follows the movement of the eye to be examined, and the display position is changed so as to maintain the relative positional relationship between the eye to be examined and the measurement line 314a specified in step S201. Is done.

  In step S210, the presence or absence of an imaging start instruction from the examiner is confirmed. If there is no imaging start instruction from the examiner, the process returns to step S206 to repeat the flow and continue the tracking operation. When an imaging start instruction is input by the examiner in step S210, the control unit 300 stops the tracking operation and starts tomographic imaging. The imaging position at this time is the fundus position under the second measurement line, and the controller 300 causes the X scanner 122-1 and the Y scanner 122 to always irradiate the same area on the fundus Er with the measurement light in the optical path L1. -2 scan position information is corrected and a tomographic image is taken.

  By the series of fundus tracking operations, the measurement light emitted from the measurement light source 130 to the fundus Er always moves so as to track the movement of the fundus Er. As a result, stable tomographic imaging can be performed. This series of fundus tracking operations is repeated until the examination of the eye E is completed.

  In the present embodiment, fundus tracking is performed using a fundus observation image by a point scanning SLO, but this may be performed using other methods. For example, fundus tracking can be performed using a two-dimensional fundus observation image acquired by combining infrared light capable of irradiating the fundus over a wide range and an infrared CCD. It is also possible to project an arbitrary pattern formed from the light source onto the fundus and perform fundus tracking using the reflected light.

  FIG. 6C illustrates the fundus display unit 313 during tracking.

  The first measurement line 314b that designates the acquisition position of the tomographic image of the present embodiment does not follow the movement of the subject's eye even during tracking execution, and continues to be displayed at the position designated by the examiner in step S201. Further, the second measurement line 314c for tracking following the eye to be examined is displayed as a character different from the first measurement line.

  Finally, the operation of the control unit 300 when the examiner inputs an interruption instruction in step S206 will be described along the flow of steps S211 to S214.

  When correcting the tomographic image acquisition site, the subject clicks the tracking start / stop button 318 described above or moves the mouse pointer 311 on or around the second measurement line 314c during the tracking operation. It is possible to give an instruction to interrupt the tracking operation. When the control unit 300 receives the tracking interruption instruction from the examiner, the control unit 300 stops the follow-up control by the second measurement line 314c in step S211. Next, in steps S212 and S213, after moving the first measurement line 314b to the position of the second measurement line 314c, the screen display of the second measurement line 314c is switched to non-display. Further, in step S214, the character display of the first measurement line is switched from the measurement line 314b being tracked to the measurement line for position designation 314a. The series of interruption processes are sequentially performed by the control unit 300. However, there is no restriction on the order of the processes, and there is no problem even if the control order is changed. Further, when the same character is used for position designation measurement line and tracking execution, step S214 can be omitted. When the processing from step S211 to S214 is completed, the control unit 300 proceeds to step S201 and waits for position designation by the examiner.

  FIG. 6D illustrates the fundus display unit 313 after the subject clicks the second measurement line 314b for tracking and finishes tracking. Since tracking is interrupted in the state of FIG. 6D, it is possible to newly set a measurement line 314a for position designation for a desired position of the eye to be examined. When the measurement line 314a is newly set in step S201, the steps after step S202 are executed again, returning to FIG. 6B, and the tracking operation is started.

  Next, the tracking interruption operation by the examiner will be described with reference to the explanatory diagrams of FIGS. 6E and 6F when an interruption area is set.

  Since the tracking measurement line 314b moves following the movement of the eye to be examined Er, it is difficult to directly select the measurement line 314b by operating the mouse. Therefore, tracking can be interrupted by moving the mouse pointer 311 into the interruption area 319 set outside the measurement line 314c. FIG. 6E shows a tracking measurement line 314c and an interruption area 319 set outside the tracking measurement line 314c. When the mouse pointer 311 is moved into the interruption area 319 by the examiner's mouse operation, the control unit 300 ends the tracking operation and starts interruption control starting from step S211 described above. After the above control is completed, the process returns to the examiner step S201, and a new position designation measurement line 314a can be set as described with reference to FIG.

  Here, FIG. 6F illustrates the fundus display unit 313 when the tracking operation is started and the control proceeds to step S204. As described above, the tracking operation may be started at the end of the mouse operation (drag) by the examiner. However, since the mouse pointer 311 is in the interruption area at the end of the drag, tracking may be interrupted immediately and the operation may not be started. Therefore, the control unit 300 executes tracking interruption control only when the mouse pointer once moves out of the interruption area and then enters the area again.

  According to the above invention, the examiner can easily determine the fixation state of the eye to be examined from the positional relationship of the second measurement line 314c with respect to the first measurement line 314b. If the second measurement line 314c is finely moved around the first measurement line 314b, it can be determined that the fixation is stable. Further, since the measurement optical path L1 and the fundus oculi observation optical path L2 of the OCT optical system are composed of separate optical systems as shown in FIG. 1, both optical systems are included in all fundus oculi observation areas due to lens aberrations and manufacturing variations. It is difficult to perfectly match the relative positions. In general, the degree of positional correlation between the two optical systems is the highest at the center of the optical system, and decreases as it reaches the end. Therefore, if a function for automatically setting the position of the first measurement line 314a to be at the center of the screen is added, shooting is performed at the timing when the automatically set first measurement line 314b and the second measurement line 314c match. By doing so, it becomes possible to acquire a tomographic image of a site desired by the examiner more precisely.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (11)

Light splitting means for splitting light from the OCT light source into a measurement optical path and a reference optical path, scanning means for scanning measurement light irradiated on the eye to be examined through the measurement optical path, and reflection from the eye to be examined by the measurement light A tomographic image acquisition means for acquiring a tomographic image of the eye to be inspected using an OCT optical system comprising: a light receiving element for detecting light synthesized from light and light from the reference optical path;
Front image acquisition means for acquiring a front image of the eye to be examined;
The tomographic image acquired by the tomographic image acquisition and the frontal image acquired by the frontal image acquisition unit are displayed on the display as moving images, and on the frontal image to set the acquisition position of the tomographic image in the eye to be examined. Display control means for moving the measurement line electronically displayed in accordance with the operation of the examiner,
An ophthalmologic imaging apparatus that acquires a tomographic image of an eye to be examined by controlling the scanning unit based on an acquisition position of the tomographic image set using the measurement line,
The measurement line indicates an acquisition position of one two-dimensional tomographic image in the eye to be examined.
The ophthalmologic photographing apparatus, wherein the display control means electronically displays the measurement line on the front image so as to surround a periphery of the acquisition position of the one two-dimensional tomographic image. A displacement detection means for detecting a displacement of the eye to be examined;
Correction means for correcting the acquisition position of the tomographic image in the eye to be examined and the position of the measurement line in the front image based on the detected displacement;
The ophthalmologic photographing apparatus according to claim 1, further comprising:   3. The ophthalmologic imaging apparatus according to claim 2, wherein the correction unit corrects the acquisition position of the tomographic image in the eye to be examined by controlling the scanning unit based on the detected positional deviation.   The correction unit includes a drive unit that moves an apparatus main body including at least the OCT optical system, and controls the drive unit based on the detected displacement, thereby obtaining the tomographic image acquisition position in the eye to be examined. The ophthalmologic photographing apparatus according to claim 2, wherein Display control means for displaying a display form indicating an acquisition position of one two-dimensional tomographic image in the eye to be examined on a front image of the eye to be examined and moving in accordance with an operation of the examiner;
A tomographic image acquisition means for acquiring one two-dimensional tomographic image of the eye to be examined based on the acquisition position of the one two-dimensional tomographic image set using the display form;
The ophthalmic imaging apparatus, wherein the display control means displays the display form on the front image so that a region of the front image corresponding to the acquisition position of the one two-dimensional tomographic image is displayed. .   The ophthalmologic photographing apparatus according to claim 5, wherein the display control unit displays the display form surrounding the acquisition position of the one two-dimensional tomographic image on the front image.   The display control means instantaneously displays one point at the acquisition position of the one two-dimensional tomographic image as a point, and the point corresponds to the acquisition position of the one two-dimensional tomographic image. The ophthalmologic photographing apparatus according to claim 5, wherein the display form is displayed on the front image by moving a partial area of the image at high speed.   The display control means displays the display form on the front image by alternately switching a frame on which the front image is displayed and a frame on which the display form is displayed. Item 6. The ophthalmologic photographing apparatus according to Item 5. Light splitting means for splitting light from the OCT light source into a measurement optical path and a reference optical path, scanning means for scanning measurement light irradiated on the eye to be examined through the measurement optical path, and reflection from the eye to be examined by the measurement light A tomographic image acquisition means for acquiring a tomographic image of the eye to be inspected using an OCT optical system comprising: a light receiving element for detecting light synthesized from light and light from the reference optical path;
Front image acquisition means for acquiring a front image of the eye to be examined;
The tomographic image acquired by the tomographic image acquisition and the frontal image acquired by the frontal image acquisition unit are displayed on the display as moving images, and on the frontal image to set the acquisition position of the tomographic image in the eye to be examined. Display control means for moving the measurement line electronically displayed in accordance with the operation of the examiner,
A control method for an ophthalmologic imaging apparatus for acquiring a tomographic image of an eye to be inspected by controlling the scanning unit based on an acquisition position of the tomographic image set using the measurement line,
The measurement line indicates an acquisition position of one two-dimensional tomographic image in the eye to be examined.
A control method for an ophthalmologic photographing apparatus, comprising: a step of electronically displaying the measurement line on the front image so as to surround a periphery of an acquisition position of the one two-dimensional tomographic image. Display control means for displaying a display form indicating an acquisition position of one two-dimensional tomographic image in the eye to be examined on a front image of the eye to be examined and moving in accordance with an operation of the examiner;
Control of an ophthalmologic imaging apparatus comprising tomographic image acquisition means for acquiring one two-dimensional tomographic image of the eye to be examined based on the acquisition position of the one two-dimensional tomographic image set using the display form A method,
A method for controlling an ophthalmologic photographing apparatus, comprising: displaying the display form on the front image so that a region of the front image corresponding to the acquisition position of the one two-dimensional tomographic image is displayed. .   A program for causing a computer to execute each step of the method for controlling an ophthalmologic photographing apparatus according to claim 9 or 10.

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