JP6877947B2 - Ophthalmologic imaging equipment and its control method - Google Patents

Description

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

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

Further, in the above-mentioned device, a scanning laser off-salmoscope (SLO optical system) for acquiring a front image of the eye to be inspected or an imaging optical system having a two-dimensional imaging element is combined with an OCT optical system. It is known that the examiner changes the imaging position in the vertical and horizontal directions of the eye to be inspected while moving the measurement line on the front image of the eye to be inspected displayed on the display by operating a predetermined switch to take a tomographic image. The position is determined.

However, in the case of the conventional device configuration, if the eye to be inspected moves during the measurement, it is difficult to observe a constant tomographic image without the influence. Therefore, Patent Document 1 discloses an ophthalmologic imaging apparatus that corrects the acquisition position of a tomographic image of an eye to be inspected based on the displacement of the eye to be inspected. At this time, in Patent Document 1, the measurement line electronically displayed on the front image for setting the acquisition position of the tomographic image in the eye to be inspected is moved according to the operation of the examiner, and the eye to be inspected is moved. It is disclosed that the position is corrected based on the misalignment.

Japanese Unexamined Patent Publication No. 2009-160190

Here, in some affected eyes, fixation is not stable and relatively large misalignment frequently occurs. In such a case, it is examined how much the measurement line moved according to the operation of the examiner to set the acquisition position of the tomographic image of the eye to be inspected is moved based on the misalignment of the eye to be inspected. It is preferable that the person can confirm it.

However, as in the conventional case, if the measurement line having a role of moving according to the operation of the examiner also has a role of position correction based on the positional deviation of the eye to be inspected, the position is corrected after the position correction. The position that existed before is not displayed. Therefore, it was not possible to strictly confirm how much the measurement line was displaced before and after the position correction of the measurement line.

One of the objects of the present invention is the front image of the eye to be inspected in order for the examiner to set the acquisition position of the tomographic image when correcting the acquisition position of the tomographic image of the eye to be inspected based on the displacement of the eye to be inspected. It is possible to easily confirm how much the display form is displaced before and after the position correction of the display form (for example, the measurement line) displayed in.

One of the ophthalmologic imaging devices according to the present invention is
An optical dividing means that divides the light from the OCT light source into a measurement optical path and a reference optical path, a scanning means that scans the measurement light emitted onto the eye to be inspected through the measurement optical path, and reflection from the eye to be inspected by the measurement light. A tomographic image acquisition means for acquiring a tomographic image of an eye to be inspected by using an OCT optical system including a light receiving element for detecting light obtained by combining light and light from the reference optical path.
Front image acquisition means for acquiring the front image of the eye to be inspected,
The tomographic image and the tomographic image acquired by the acquiring a front image obtained by the front image acquisition unit is displayed on the display as a moving image Rutotomoni, the front image in order to set the acquisition position of the tomographic image to be examined A display control means that controls the display so that the position of the first measurement line electronically displayed above is changed according to the operation of the examiner.
A misalignment detecting means for detecting the misalignment of the eye to be inspected is provided.
In a state where the acquisition position of the tomographic image set by using the first measurement line is controlled so as to be corrected based on the detected positional deviation, the scanning means is controlled to control the tomographic image of the eye to be inspected. An ophthalmic imaging device that acquires images
In a state where the front Symbol first measurement line is displayed on the changed position, a second measurement line different from the first measurement line, the is electronically displayed on the front image A correction means for correcting the position of the second measurement line based on the detected positional deviation from the changed position of the first measurement line.
With
The display control means changes the position of the first measurement line from the changed position of the first measurement line in a state where the second measurement line is displayed at the corrected position. The display is controlled according to the operation of the examiner so as to change to the corrected position of the measurement line of.

Further, one of the ophthalmologic imaging devices according to the present invention is
The display means is such that the first display form indicating the acquisition position of the tomographic image of the eye to be inspected is displayed on the front image of the eye to be inspected, and the position of the first display form is changed according to the operation of the examiner. and display control means for performing control,
A tomographic image acquisition means for acquiring a tomographic image of an eye to be inspected in a state where the acquisition position of the tomographic image set by using the first display mode is controlled so as to be corrected based on the displacement of the eye to be inspected. When,
In a state where the first display mode before Symbol is displayed on the changed position, wherein the first display forms a different second display mode, the second display form displayed on the front image A correction means for correcting the position of the eye from the changed position of the first display form based on the positional deviation of the eye to be inspected.
The display control means changes the position of the first display form from the changed position of the first display form in a state where the second display form is displayed at the corrected position. The display means is controlled so as to change to the corrected position of the display form of.

According to one of the present inventions, when correcting the acquisition position of the tomographic image of the eye to be inspected based on the displacement of the eye to be inspected, the examiner sets the acquisition position of the tomographic image in order to set the front image of the eye to be inspected. It is possible to easily confirm how much the display form is displaced before and after the position correction of the display form (for example, the measurement line) displayed in.

The figure which shows the structural example of the ophthalmologic imaging apparatus which concerns on embodiment. The figure which shows the operation screen example which concerns on embodiment The flowchart which shows an example of the automatic alignment operation which concerns on embodiment. The flowchart which shows an example of the fundus tracking operation which concerns on 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 which concerns on embodiment.

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

<Outline configuration of ophthalmic imaging device>
The schematic configuration of the ophthalmologic imaging apparatus (optical interference tomographic imaging apparatus) according to the present embodiment will be described with reference to FIG. The ophthalmologic imaging device acquires a tomographic image of the eye to be inspected based on the interference light that interferes with the return light from the eye to be inspected that is irradiated with the measurement light through the scanning unit and the reference light corresponding to the measurement light. .. The ophthalmologic imaging apparatus includes an optical head unit 100, a spectroscope 200, and a control unit 300. Hereinafter, the configurations of the optical head unit 100, the spectroscope 200, and the control unit 300 will be described in order.

<Structure of optical head unit 100 and spectroscope 200>
The optical head unit 100 is composed of 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 inspected and the fundus Er of the eye to be inspected. Hereinafter, the inside of the optical head unit 100 will be described. The objective lens 101-1 is installed facing the eye E to be inspected, and the optical path is separated by the first dichroic mirror 102 and the second dichroic mirror 103, which are provided on the optical axis of the objective lens 101-1 and function as an optical path separation unit. .. That is, it is branched into the measurement optical path L1 of the OCT optical system, the fundus observation optical path and the fixation lamp optical path L2, and the anterior eye observation optical path L3 for each wavelength band.

The optical path L2 is further branched by a third dichroic mirror 118 into an optical path to an APD (avalanche photodiode) 115 for observing the fundus and a fixation lamp 116 for each wavelength band. Here, 101-2, 111, and 112 are lenses, and the lens 111 is driven by a fixed vision lamp and a motor (not shown) for focusing adjustment for fundus observation. The APD 115 has a sensitivity in the wavelength of the illumination light for fundus observation (not shown), specifically in the vicinity of 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) and a Y scanner 117-2 for scanning the light emitted from an illumination light source for observing the fundus (not shown) on the fundus Er of the eye E to be inspected. (For the sub-scanning direction that intersects the main scanning direction) is arranged. The lens 101-2 is arranged with the vicinity of the center position of the X scanner 117-1 and the Y scanner 117-2 as the focal position. Although the X scanner 117-1 is composed of a resonance type mirror, it 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 to be inspected E are configured to have an optically conjugate relationship. Further, the APD (avalanche photodiode) 115 is a single detector and detects the light scattered / reflected from the fundus Er and returned. The third dichroic mirror 118 is a prism on which a perforated mirror or a hollow mirror is vapor-deposited, and separates the illumination light and the return light from the fundus Er.

A lens 141 and an infrared CCD 142 for frontal eye observation are arranged in the optical path L3. The infrared CCD 142 has a sensitivity in the wavelength of the illumination light for frontal eye observation (not shown), specifically in the vicinity of 970 nm. The optical path L1 forms an OCT optical system as described above, and is used for capturing a tomographic image of the fundus Er of the eye to be inspected. 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, an X scanner 122-1 that functions as a scanning unit for scanning light on the fundus Er of the eye to be inspected, and a Y scanner 122-2 are arranged. 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, and further, the X scanner 122- 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 inspected have an optical conjugate relationship. With this configuration, the optical path with the scanning portion as the object point is substantially parallel between the lens 101-1 and the lens 101-3. As a result, even if the X scanner 122-1 and the Y scanner 122-2 scan, the angles incident on the first dichroic mirror 102 and the second dichroic mirror 103 can be made the same.

Further, the measurement light source 130 serves as an OCT light source for incidenting the measurement light into the measurement optical path. In the case of 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 inspected. Reference numerals 123 and 124 are lenses, of which the lens 123 is driven by a motor (not shown) for focusing adjustment. The focusing adjustment is performed so that the light emitted from the measurement light source 130, which is the fiber end, is imaged on the fundus Er. The lens 123 that functions as a focusing adjustment unit is arranged between the measurement light source 130 and the X scanner 122-1 and the Y scanner 122-2 that function as scanning units. This eliminates the need to move the larger lens 101-3 and the optical fiber 125-2.

By this focusing adjustment, an image of the measurement light source 130 can be formed on the fundus Er of the eye E to be inspected, and the return light from the fundus Er of the eye E to be inspected 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 paper surface, but is actually configured in the direction perpendicular to the paper surface. Further, the optical head unit 100 includes a head drive unit 140. The head drive unit 140 is composed of three motors (not shown), and the optical head unit 100, which is an example of a device main body having at least an OCT optical system built-in, is three-dimensionally (X, Y, Z) with respect to the eye E to be inspected. ) It is configured to be movable in the direction. As a result, the optical head portion 100 can be aligned with the eye E to be inspected.

Next, the configuration of the optical path from the measurement light source 130, the reference optical system (reference optical path), and the spectroscope 200 will be described. A Michelson interferometer is composed of a measurement light source 130, an optical coupler 125, an optical fiber 125-1 to 4, a lens 151, a dispersion compensation glass 152, a mirror 153, and a spectroscope 200. Optical fibers 125-1 to 125-4 are single-mode optical fibers connected to and integrated with the optical coupler 125.

The light emitted from the measurement light source 130 is divided 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 an optical dividing means that divides the light emitted from the measuring light source 130 into the measuring light and the reference light. The measurement light is irradiated to the fundus Er of the eye E to be observed through the above-mentioned OCT optical path, and reaches the optical coupler 125 through the same optical path by 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 compensating glass 152 inserted to match the dispersion of the measurement light and the reference light. Then, it returns to the optical coupler 125 through the same optical path. The optical coupler 125 combines the measurement light and the reference light into interference light. Here, interference occurs when the optical path length of the measurement light and the optical path length of the reference light are almost the same. The position of the mirror 153 is adjustablely held in the optical axis direction by a motor and a drive mechanism (not shown), 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 to be inspected. The interfering light is guided to the spectroscope 200 via 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 separated 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 Luminate 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. Although SLD was selected as the type of light source here, ASE (Amplified Spontaneous Emission) or the like can also be used as long as low coherent light can be emitted. Near-infrared light is appropriate as the center wavelength in view of measuring the eye. Further, since the central wavelength affects the lateral resolution of the obtained tomographic image, it is desirable that the wavelength is as short as possible. For both reasons, the center wavelength was set to 855 nm.

Although the Michelson interferometer is used as the interferometer in this embodiment, 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 to use a Michelson interferometer when the light amount difference is relatively small.

<Structure of control unit 300>
The control unit 300 is connected to each unit 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 is configured to be able to generate an observation image of the anterior eye portion Ea of the eye E to be inspected. Further, the control unit 300 is also connected to the APD 115 in the optical head unit 100, and is configured to be able to generate an observation image (front image acquisition) of the fundus Er of the eye to be inspected E. Further, the control unit 300 is also connected to the head drive unit 140 in the optical head unit 100, and is configured to be able to drive the optical head unit 100 three-dimensionally with respect to the eye E to be inspected. On the other hand, the control unit 300 is also connected to the line sensor 204 of the spectroscope 200. As a result, the measurement signal wavelength-decomposed by the spectroscope 200 can be acquired, and a tomographic image of the eye E to be inspected can be generated based on the measurement signal. The generated anterior segment observation image, fundus observation image (frontal image), and tomographic image of the eye E to be inspected 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 the display control means, displays the acquired images of the eye E to be inspected on the anterior eye unit display unit 312, the fundus display unit 313, and the tomographic image display units 315 and 316. Further, as will be described later in the explanation of tracking, a tomographic image measurement line 314 that can be set by the examiner is electronically superimposed and displayed on the fundus observation image (on the front image) as a character image in the fundus display unit 313. .. In FIG. 2, the measurement lines 314 are displayed as vertical and horizontal intersection lines, 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, FIG. 2 displays a mouse pointer (cursor) 311 that can be operated by the examiner, a tracking start / stop button 318, and a measurement start button 317. The monitor 301 may display a slider for adjusting the focal position of the measurement light, a slider for changing the depth position of the tomographic image, and the like.

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

In step S101, the examiner drives an operating means (not shown) and a motor that can be driven in three-dimensional (X, Y, Z) directions, and the pupil of the eye E to be inspected is displayed on the anterior segment observation image display portion on the monitor 301. The optical head unit 100 is moved so that a part of the optical head unit 100 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 S102, the control unit 300 functions as an anterior segment image acquisition unit, and when automatic alignment is started, periodically acquires an anterior segment image from the infrared CCD 142 and analyzes it. Specifically, the control unit 300 detects the 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 displacement amount calculation unit, and calculates a displacement amount (positional displacement amount) between the detected center position of the pupil region and the center position of the anterior segment image. The ophthalmologic imaging apparatus of the present embodiment is configured so that the center of the anterior segment image and the optical axis of the objective lens 101-1 coincide with each other, and the displacement amount calculated in step S104 is the eye E to be inspected and the optical axis to be measured. It represents the amount of misalignment with.

In step S105, the control unit 300 instructs the head drive unit 140 to move the optical head unit 100 according to the amount of misalignment calculated in step S104. In step S206, the head drive 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 to be inspected. As a result of the movement, the position of the optical axis of the objective lens 101-1 mounted on the optical head portion 100 is corrected so as to approach the pupil center position of the anterior segment Ea of the eye E to be inspected.

In step S107, after the optical head unit 100 is moved, the control unit 300 acquires the anterior eye portion image from the infrared CCD 142 again and performs pupil detection. Here, it is determined whether or not the pupil of the eye E to be inspected has been moved within the preset designated area. When it is determined that the fixation of the eye to be inspected is stable and the pupil has been moved within the designated region (S107; YES), the automatic alignment process is terminated.

On the other hand, when the pupil of the eye to be inspected does not fit in the predetermined region (S207; NO), it is determined that the optical axis of the objective lens 101-1 mounted on the optical head portion 100 and the optical axis of the eye to be inspected do not match. The process returns to step S102 and 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 segment Ea of the eye E to be inspected. Even if the line-of-sight direction of the eye E to be inspected changes, the optical axis of the objective lens 101-1 tracks the center of the pupil of the anterior segment Ea after the line-of-sight change (anterior eye tracking) by this automatic alignment operation. Therefore, the measured luminous flux emitted from the measuring light source 130 is applied to the fundus Er without being blocked by the pupil, and a stable tomographic image can be taken.

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

In the present embodiment, the automatic alignment of the optical system with respect to the eye to be inspected is performed based on the image of the anterior segment using the infrared CCD, but this may be performed by using another method. For example, by projecting an index for alignment onto the anterior segment of the eye to be inspected and detecting the reflected light, automatic alignment in the three-dimensional (X, Y, Z) direction can be performed.

<How to take a tomographic image>
Next, a method of photographing a tomographic image using the ophthalmologic imaging apparatus of the present embodiment will be described.

After the above-mentioned automatic alignment operation is completed, the control unit 300 starts the operation of acquiring the two-dimensional observation image of the fundus Er through the optical path L2. Specifically, the control unit 300 starts acquiring the reflected light from the fundus Er that is 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 periodically synthesizing the reflected light input from the APD 115, it is possible to periodically obtain an observation image of the fundus Er. The obtained observation image is displayed on the fundus display unit 313 of FIG.

The examiner observes the fundus image Er, sets the tomographic image on the desired site, and specifies the measurement site using the character image. When the designation of the measurement site is completed, the measurement start button 317 arranged on the monitor 301 is operated to start photographing. The control unit 300 periodically starts generating a tomographic image for recording based on the interference light output from the line sensor 204 in accordance with the instruction to start photographing.

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 processes the signal of the line sensor 204 by FFT (Fast Fourier Transform) to generate information in the depth direction at a certain point on the fundus Er. Information generation in the depth direction at a certain point on the fundus Er is called an A scan.

Then, the measurement light applied 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 inspected by the X scanner 122-1 and the Y scanner 122-2.

The control unit 300 generates a tomographic image on an arbitrary locus on the fundus Er by bundling a series of a plurality of A scans acquired during one scan according to the arbitrary locus into one 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 to repeat the scanning according to the above-mentioned arbitrary locus a plurality of times. When the same locus is operated 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 to repeatedly execute scanning in the X direction, and generates a plurality of tomographic images on the same scanning line of the fundus Er. Further, the control unit 300 can simultaneously drive the X scanner 122-1 and the Y scanner 122-2 to repeatedly execute a circular operation to generate a plurality of tomographic images on the same circle of the fundus Er. Then, the control unit 300 generates one high-quality tomographic image by adding and averaging the plurality of tomographic images, and displays them on the tomographic image display units 315 and 316 on the monitor 301.

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

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

<Fundus tracking method>
Further, the tracking method of the present embodiment will be described with reference to the flowchart of FIG. 4 and the measurement line display example of FIGS. 5 and 6.

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

In this embodiment, a method of acquiring a two-dimensional tomographic image obtained by X-axis scanning, which is the basis of acquiring a tomographic image, will be described as an example.

In step S201, the examiner superimposes the position designation measurement line 314a (first measurement line) on the fundus image Er on the fundus display unit 313, and displays the part of the tomographic image to be acquired at 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 to specify the position designation measurement line 314a in the direction of the macula from the center of the papilla. Here, the position designation measurement line 314a of FIG. 6 has a hollow display in which the central portion of the measurement line is transparent. Generally, even a two-dimensional measurement line in the X-axis scanning direction requires a width of several Dots in order to be displayed in an easy-to-understand manner by the examiner, and in a normal line display, the fundus image of the part to be acquired is always a line. Sometimes it was hidden. Therefore, by displaying the position designation measurement line as a hollow display, it is possible to facilitate the observation of the fundus region that the examiner actually wants to acquire. Here, as a method for facilitating the observation of the fundus image under the measurement line, the shape of the position designation measurement line 314a, which is an example of the first display form, is not limited to this embodiment. As another method, for example, one point having a position corresponding to the measurement line on the fundus image is momentarily displayed as a point, and the position corresponding to the measurement line is moved at high speed to the fundus image. There is a method to show the acquisition position of the tomographic image above. Further, for example, the frame in which the measurement line is displayed without displaying the fundus image of the eye to be inspected and the frame in which the fundus image of the eye to be inspected 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 the image. By performing control using the optical illusion of the examiner as described above, it is possible to observe the fundus image directly below the line while displaying the measurement line. Further, the fundus image by the SLO optical system is displayed in gray scale on the fundus display unit 313. Therefore, by changing the display of the portion of the fundus image instructed by the examiner from the grayscale display to the 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 the second display mode described later, is not limited to this embodiment and may be the shape as described above.

In this embodiment, one measurement line for X-axis scanning is described for simplification of explanation, 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 set individually for each of the vertical and horizontal measurement lines, and the vertical and horizontal measurement lines can be hollowed out to be below the measurement line. It is possible to easily observe the fundus image. Further, when generating a three-dimensional map of a tomographic image, it is possible to specify a rectangular shape that encloses the entire desired area instead of a line shape when setting the position.

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 images acquired periodically according to the start signal from the examiner. In addition to the button operation described above, it is also possible to start tracking at the end of the mouse drag operation in S201.

Subsequently, a method of displaying the measurement line of the present embodiment will be described. In the conventional control, the above-mentioned first measurement line follows the movement of the eye to be inspected and corrects the tomographic image acquisition position. However, with such control, it is not possible to easily determine how much the eye to be inspected has moved from the designated position, and there is a concern that it is difficult to find problems such as abnormal fixation of the eye to be inspected.

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 hollowed out position designation measurement line 314a. In the present embodiment, since the position designation measurement line 314a has a hollow display as described above, the tracking measurement line 314c is displayed inside the measurement line 314a for improving 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 and the superimposed character image of the fundus display unit 313 at the end of steps S203 and S204.

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

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

Subsequently, tracking control using the above measurement line will be described.

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

If the interruption instruction from the examiner is not confirmed in step S206, the control unit 300 proceeds to step 207 to acquire the fundus observation image again. In step S208, the control unit 300 calculates the amount of movement of the fundus Er using the two fundus observation images, the previously acquired fundus observation image and the current fundus observation image. Specifically, the control unit 300 calculates the amount of displacement of the region of interest on the fundus observation image in the two-dimensional (X, Y) direction to determine the amount of movement of the fundus Er in the two-dimensional (X, Y) direction. calculate. The control unit 300 is an example of a movement amount acquisition means for acquiring 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 inspected acquired at different times. The region of interest is the macula of the fundus, the optic nerve head, the bifurcation of blood vessels, and the like, and any region on the fundus can be used as long as the amount of movement 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 display position of the second measurement line 314c during tracking control is changed so as to follow the movement of the eye to be inspected and maintain the relative positional relationship between the eye to be inspected and the measurement line 314a specified by the examiner in step S201. Is done.

In step S210, it is confirmed whether or not the examiner has instructed to start photographing. If there is no instruction to start shooting by the examiner, the tracking operation is continued by returning to step S206 and repeating the flow. When the examiner inputs an imaging start instruction in step S210, the control unit 300 stops the tracking operation and starts imaging the tomographic image. The imaging position at this time is the position of the fundus below the second measurement line, and the control unit 300 controls the X scanner 122-1 and the Y scanner 122 so that the measurement light of the optical path L1 always irradiates the same region on the fundus Er. -Correct the scanning position information of -2 and take a tomographic image.

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 to be inspected. Therefore, stable tomographic images can be taken. Then, this series of fundus tracking operations is repeated until the examination of the eye E to be inspected 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 by using another method. 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 a light source onto the fundus and use the reflected light to perform fundus tracking.

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

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

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

When correcting the tomographic image acquisition site, the subject can click the tracking start / stop button 318 described above, or move the mouse pointer 311 on or around the second measurement line 314c during the tracking operation. It is possible to give an instruction to suspend the tracking operation. When the control unit 300 receives the tracking interruption instruction by the examiner, the control unit 300 stops the tracking control by the second measurement line 314c in step S211. Then, 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 during tracking execution to the position designation measurement line 314a. Although the series of interruption processes are sequentially performed by the control unit 300, there is no restriction on the order of the processes, so there is no problem even if the control order is changed. Further, when the same character is used for the position designation measurement line at the time of position designation and at the time of tracking execution, step S214 can be omitted. When the processes from steps S211 to S214 are completed, the control unit 300 proceeds to step S201 and is in a state of waiting for the position designation by the inspector.

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

Next, the tracking interruption operation by the examiner will be described with reference to the explanatory diagrams of FIGS. 6 (e) and 6 (f) in the case where the interruption area is set.

Since the measurement line 314b during tracking moves following the movement of the eye to be inspected Er, it is difficult to directly select the measurement line 314b by operating the mouse. Therefore, it is possible to interrupt the tracking by moving the mouse pointer 311 into the interruption area 319 set outside the measurement line 314c. FIG. 6 (e) shows the tracking measurement line 314c and the interruption area 319 set outside the tracking measurement line 314c. When the mouse pointer 311 is moved into the interruption area 319 by the mouse operation of the examiner, the control unit 300 ends the tracking operation and starts the interruption control starting from step S211 described above. After the above control is completed, the process returns to the examiner step S201, and the position designation measurement line 314a can be newly set as described in FIG. 6A.

Here, FIG. 6F illustrates the fundus display unit 313 at the time when the tracking operation is started and the control progresses to step S204. As described above, the start of the tracking operation may be coincident with 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 dragging, tracking may be interrupted immediately and the operation may not be started. Therefore, the control unit 300 executes the tracking interruption control only when the mouse pointer moves out of the interruption area once and then invades the area again.

According to the above invention, the examiner can easily determine the fixation state of the eye to be inspected 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 slightly 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 observation optical path L2 of the OCT optical system are composed of separate optical systems as shown in FIG. 1, the relative of both optical systems within the entire fundus observation region due to lens aberration and manufacturing variation. It is difficult to match the positions exactly. Generally, the degree of positional correlation between the two optical systems is highest at the center of the optical system, and decreases toward the edges. Therefore, if a function of automatically setting the position of the first measurement line 314a to be the center of the screen is added, the image is taken 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 accurately.

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

Claims (12)

An optical dividing means that divides the light from the OCT light source into a measurement optical path and a reference optical path, a scanning means that scans the measurement light emitted onto the eye to be inspected through the measurement optical path, and reflection from the eye to be inspected by the measurement light. A tomographic image acquisition means for acquiring a tomographic image of an eye to be inspected by using an OCT optical system including a light receiving element for detecting light obtained by combining light and light from the reference optical path.
Front image acquisition means for acquiring the front image of the eye to be inspected,
The tomographic image and the tomographic image acquired by the acquiring a front image obtained by the front image acquisition unit is displayed on the display as a moving image Rutotomoni, the front image in order to set the acquisition position of the tomographic image to be examined A display control means that controls the display so that the position of the first measurement line electronically displayed above is changed according to the operation of the examiner.
A misalignment detecting means for detecting the misalignment of the eye to be inspected is provided.
In a state where the acquisition position of the tomographic image set by using the first measurement line is controlled so as to be corrected based on the detected positional deviation, the scanning means is controlled to control the tomographic image of the eye to be inspected. An ophthalmic imaging device that acquires images
In a state where the front Symbol first measurement line is displayed on the changed position, a second measurement line different from the first measurement line, the is electronically displayed on the front image A correction means for correcting the position of the second measurement line based on the detected positional deviation from the changed position of the first measurement line.
With
The display control means changes the position of the first measurement line from the changed position of the first measurement line in a state where the second measurement line is displayed at the corrected position. An ophthalmologic imaging apparatus, characterized in that the display is controlled according to an operation of an examiner so as to change to the corrected position of the measurement line of the above. The ophthalmologic imaging apparatus according to claim 1, wherein the correction means corrects the acquisition position of the tomographic image in the eye to be inspected by controlling the scanning means based on the detected positional deviation. The correction means includes a drive unit for moving at least the main body of the device incorporating the OCT optical system, and controls the drive unit based on the detected positional deviation to obtain the tomographic image acquisition position in the eye to be inspected. The ophthalmologic imaging apparatus according to claim 1, wherein the image is corrected. Wherein the display control unit, said When the cursor displayed on the display in response to the operation of the examiner came on the second measurement line, the position of the first measuring line of the first measurement line The ophthalmologic imaging apparatus according to any one of claims 1 to 3 , wherein the display is controlled so as to change from the changed position to the corrected position of the second measurement line. .. Said display control means, when the second measurement line is instructed according to the examiner operating the cursor displayed on the display, the position of the first measuring line of the first measurement line The ophthalmologic imaging apparatus according to any one of claims 1 to 3 , wherein the display is controlled so as to change from the changed position to the corrected position of the second measurement line. .. The display means is such that the first display form indicating the acquisition position of the tomographic image of the eye to be inspected is displayed on the front image of the eye to be inspected, and the position of the first display form is changed according to the operation of the examiner. and display control means for performing control,
A tomographic image acquisition means for acquiring a tomographic image of an eye to be inspected in a state where the acquisition position of the tomographic image set by using the first display mode is controlled so as to be corrected based on the displacement of the eye to be inspected. When,
In a state where the first display mode before Symbol is displayed on the changed position, wherein the first display forms a different second display mode, the second display form displayed on the front image A correction means for correcting the position of the eye from the changed position of the first display form based on the positional deviation of the eye to be inspected.
The display control means changes the position of the first display form from the changed position of the first display form in a state where the second display form is displayed at the corrected position. An ophthalmologic imaging apparatus, characterized in that the display means is controlled so as to change to the corrected position of the display form of. When the cursor displayed on the display means comes over the second display form in response to the operation of the examiner, the display control means sets the position of the first display form in the first display form. The ophthalmologic imaging apparatus according to claim 6 , wherein the display means is controlled so as to change from the changed position to the corrected position of the second display form. When the second display form is instructed by the cursor displayed on the display means according to the operation of the examiner, the display control means sets the position of the first display form of the first display form. The ophthalmologic imaging apparatus according to claim 6 , wherein the display means is controlled so as to change from the changed position to the corrected position of the second display form. The first display form shows the acquisition position of one two-dimensional tomographic image in the eye to be inspected, and is displayed on the front image so as to surround the periphery of the acquisition position of the one two-dimensional tomographic image.
In the second display form, when the correction by the correction means is started after the first display form is moved to the position of the second display form, the peripheral portion is surrounded by the first display form. The ophthalmologic imaging apparatus according to any one of claims 6 to 8, wherein the ophthalmologic imaging apparatus is displayed inside the display form of the above. An optical dividing means that divides the light from the OCT light source into a measurement optical path and a reference optical path, a scanning means that scans the measurement light emitted onto the eye to be inspected through the measurement optical path, and reflection from the eye to be inspected by the measurement light. A tomographic image acquisition means for acquiring a tomographic image of an eye to be inspected by using an OCT optical system including a light receiving element for detecting light obtained by combining light and light from the reference optical path.
Front image acquisition means for acquiring the front image of the eye to be inspected,
The tomographic image and the tomographic image acquired by the acquiring a front image obtained by the front image acquisition unit is displayed on the display as a moving image Rutotomoni, the front image in order to set the acquisition position of the tomographic image to be examined A display control means that controls the display so that the position of the first measurement line electronically displayed above is changed according to the operation of the examiner.
A misalignment detecting means for detecting the misalignment of the eye to be inspected is provided.
In a state where the acquisition position of the tomographic image set by using the first measurement line is controlled so as to be corrected based on the detected positional deviation, the scanning means is controlled to control the tomographic image of the eye to be inspected. It is a control method of an ophthalmologic imaging device that acquires images.
In a state where the front Symbol first measurement line is displayed on the changed positions, the first of the measurement lines a different second measurement line, the front image based on the detected positional deviation A step of correcting the position of the second measurement line electronically displayed above from the changed position of the first measurement line, and
With the second measurement line displayed at the corrected position, the position of the first measurement line is corrected from the changed position of the first measurement line to the correction of the second measurement line. The process of controlling the display according to the operation of the examiner so as to change the position to the position
A method for controlling an ophthalmologic imaging apparatus, which comprises. The display means is such that the first display form indicating the acquisition position of the tomographic image of the eye to be inspected is displayed on the front image of the eye to be inspected, and the position of the first display form is changed according to the operation of the examiner. and display control means for performing control,
A tomographic image acquisition means for acquiring a tomographic image of an eye to be inspected in a state where the acquisition position of the tomographic image set by using the first display mode is controlled so as to be corrected based on the displacement of the eye to be inspected. It is a control method of an ophthalmologic imaging device equipped with
In a state where the first display mode before Symbol is displayed on the changed position, wherein the first display forms a different second display mode, the second display form displayed on the front image The step of correcting the position of the eye from the changed position of the first display form based on the positional deviation of the eye to be inspected, and
In a state where the second display form is displayed at the corrected position, the position of the first display form is changed from the changed position of the first display form to the correction of the second display form. A step of controlling the display means according to the operation of the examiner so as to change the position to the designated position, and
A method for controlling an ophthalmologic imaging apparatus, which comprises. A program comprising causing a computer to execute each step of the control method of the ophthalmologic imaging apparatus according to claim 10 or 11.

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