JP5766225B2 - Optical tomographic imaging apparatus and control method - Google Patents

Description

  The present invention relates to an optical tomographic imaging apparatus used for ophthalmic medical care and the like, and a control method therefor.

  2. Description of the Related Art In recent years, an optical image measurement technique that forms an image of the surface or inside of an object to be measured using light attracts attention. Since the optical image measurement technique does not have invasiveness to the human body unlike conventional X-ray CT, it is expected to be applied particularly in the medical field. Above all, the application in the field of ophthalmology has made remarkable progress.

  As a typical technique of optical image measurement technology, there is a technique called optical coherence tomography (optical coherence tomography: OCT). According to this method, since an interferometer is used, measurement with high resolution and high sensitivity is possible. In addition, since weak broadband light is used as illumination light, there is also an advantage that safety to the subject is high.

  An optical tomographic imaging apparatus based on optical coherence tomography (OCT: Optical Coherence Tomography: hereinafter referred to as an OCT apparatus) using optical interference according to the present invention can obtain a tomographic image of a sample with high resolution. In particular, the present invention relates to an anterior ocular segment optical tomography apparatus for forming an anterior segment image of an eye to be examined.

  According to the OCT apparatus, measurement light, which is low-coherent light, is irradiated on a sample, and backscattered light from the sample can be measured with high sensitivity by using an interference system or an interference optical system. Further, the OCT apparatus can obtain a high-resolution tomographic image by scanning the measurement light on the sample. Therefore, a tomographic image of the corneal region in the anterior segment of the eye to be examined is acquired and used in ophthalmic diagnosis and the like.

  Here, Patent Document 1 discloses an optical tomographic imaging apparatus capable of capturing both an anterior ocular segment tomographic image and a fundus tomographic image. This moves the reference mirror in the interference optical system to a position corresponding to the imaging mode in accordance with the anterior segment imaging mode and the fundus imaging mode.

JP 2011-147612 A

  Here, it is considered to change the size of the imaging range of a tomographic image of an inspection object such as an eye to be inspected. At this time, a method of changing the optical path length of the measurement light by moving the apparatus main body in the optical axis direction with respect to the object to be inspected can be considered. In this method, the examiner does not easily know how much the optical path length of the measurement light is changed to obtain the tomographic image with the intended size.

  In view of the above problems, the present invention is to easily acquire a tomographic image of an intended size if the examiner indicates the size of the imaging range of the tomographic image of the object to be inspected.

The present invention provides an optical tomographic imaging apparatus configured as follows.
That is, the optical tomographic imaging apparatus according to the present invention, a return light from the anterior segment of the examinee eye is irradiated with measurement light, the surveying constant light the anterior based on light multiplexes the reference light corresponding to An optical tomographic imaging apparatus for acquiring a tomographic image of a portion , wherein a measuring optical path length changing unit for changing an optical path length of the measuring light and a display mode for receiving an instruction of a size of an imaging range of the tomographic image Display control means to be displayed on the display, and control means for controlling the measurement optical path length changing means in accordance with an instruction received by the display form.

  According to the present invention, the optical path length of the measurement light can be changed when the display form displayed on the display unit receives an instruction of the size of the imaging range of the tomographic image. Thereby, if the examiner indicates the size of the imaging range of the tomographic image of the object to be inspected, the tomographic image having the intended size can be easily acquired.

It is the figure shown about the whole apparatus about one Embodiment of this invention. It is the figure which showed the measurement optical system structure about one Embodiment of this invention. It is explanatory drawing which showed a mode that the to-be-examined eye was scanning the anterior eye part in the x direction. It is explanatory drawing which showed the scanning range in the anterior ocular segment imaging position, and the image obtained according to this scanning range. It is the figure which showed an example of the measurement operation screen. It is the figure which showed the other example of the measurement operation screen. It is the figure which showed the measurement flow in connection with one Embodiment of this invention. It is a figure which shows the example of a display of the tomographic image of an anterior eye part, and the example which correct | amended and displayed the said image.

  Hereinafter, the best embodiment of the present invention will be described.

[First Embodiment]
An optical tomographic imaging apparatus (OCT apparatus) to which the present invention is applied will be described below as a first embodiment of the present invention.

(Schematic configuration of the device)
A schematic configuration of the optical tomographic imaging apparatus according to the present embodiment will be described with reference to FIG.
FIG. 1 is a side view of the optical tomographic imaging apparatus. 200 is an optical tomographic imaging apparatus, 900 is an optical head that is a measurement optical system for capturing a two-dimensional image and a tomographic image of the anterior segment of the eye, and 950 is moved using a motor (not shown) in the xyz direction This is a stage unit that is a movable unit. Reference numeral 951 denotes a base unit incorporating a spectroscope described later.

  Reference numeral 925 denotes a personal computer that also serves as a control unit for the stage unit, and performs tomographic image configuration and the like along with control of the stage unit. A hard disk 926 also serves as a subject information storage unit and stores a program for tomographic imaging. A monitor 928 is a display unit, and an input unit 929 is an instruction unit for instructing a personal computer, and specifically includes a keyboard and a mouse. Reference numeral 323 denotes a chin stand that fixes the subject's chin and forehead to promote fixation of the subject's eyes (eye to be examined). Reference numeral 324 denotes an external fixation lamp, which is used to fixate the eye of the subject. It can be used by switching to an internal fixation lamp described later.

(Configuration of measurement optical system and spectrometer)
The configuration of the measurement optical system and the spectroscope of this embodiment will be described with reference to FIG.
First, the inside of the optical head 900 will be described. The objective lenses 101-1 and 101-2 are installed facing the eye 100, and the optical path L1 of the OCT optical system, the anterior eye portion observation and the internal fixation lamp are arranged on the optical axis by the reflection mirror 102 and the dichroic mirror 103. Branches to the optical path L2 for each wavelength band.

  The optical path L2 is further branched for each wavelength band by the third dichroic mirror 104 to the optical path to the anterior segment observation CCD 105 and the internal fixation lamp 106 as described above. Here, reference numerals 101-3, 107, and 108 denote lenses, and 107 is driven by a motor (not shown) for focusing adjustment for fixation lamp and anterior eye portion observation. The CCD 105 has sensitivity at the wavelength of illumination light for anterior ocular segment observation (not shown), specifically around 780 nm. On the other hand, the internal fixation lamp 106 generates visible light and promotes fixation of the subject.

  The optical path L1 forms the OCT optical system as described above, and is for capturing a tomographic image of the anterior segment 100-1 of the eye 100 to be examined. More specifically, an interference signal for forming a tomographic image is obtained. In the optical path L1, a lens 101-4, a mirror 113, and an X scanner 114-1 and a Y scanner 114-2 for scanning light on the anterior eye portion 100-1 of the eye 100 to be examined are arranged. Reference numerals 115 and 116 denote lenses, and the lens 115 adjusts the focus of the light from the light source 118 emitted from the fiber 117-2 connected to the optical coupler 117 onto the anterior eye portion 100-1. Therefore, it is driven by a motor (not shown). By this focusing adjustment, the light from the anterior segment 100-1 is simultaneously focused on and incident on the tip of the fiber 117-2.

Next, the configuration of the optical path from the light source 118, the reference optical system, and the spectroscope will be described.
118 is a light source, 119 is a mirror, 120 is a dispersion compensation glass, 117 is an optical coupler as described above, 117-1 to 4 are integrated with a single mode optical fiber, 121 is a lens, and 180 is a spectroscopic unit. It is a vessel.

  The Michelson interference system is configured by these configurations. The light emitted from the light source 118 is split into measurement light on the optical fiber 117-2 side and optical fiber 117-3 reference light through an optical coupler 117-1 through an optical fiber 117-1. The measurement light is irradiated on the fundus of the eye 100 to be inspected through the OCT optical system optical path described above, and reaches the optical coupler 117 through the same optical path due to reflection and scattering by the retina.

  On the other hand, the reference light reaches the reference mirror 119 and is reflected through the optical fiber 117-3, the lens 121, and the dispersion compensation glass 120 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 117. The measurement light and the reference light are combined by the optical coupler 117 and become interference light. Here, interference occurs when the optical path length of the measurement light and the optical path length of the reference light satisfy a predetermined condition. The reference mirror 119 is held so as to be adjustable 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 changed by the anterior eye unit 100-1. The interference light is guided to the spectroscope 180 via the optical fiber 117-4.

  The spectroscope 180 includes lenses 181 and 183, a diffraction grating 182, and a line sensor 184. The interference light emitted from the optical fiber 117-4 becomes substantially parallel light via the lens 181, and then is dispersed by the diffraction grating 182 and imaged on the line sensor 184 by the lens 183. The licensor 184 is shown as an example of a light receiving element that receives interference light and generates and outputs an output signal corresponding to the interference light in the present invention.

  Next, the periphery of the light source 118 will be described. The light source 118 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. In view of measuring the eye, the center wavelength is preferably near infrared light. 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.

(Tomographic imaging method)
A tomographic image capturing method using the optical tomographic imaging apparatus will be described. By controlling the X scanner 114-1 and the Y scanner 114-2, the optical tomographic imaging apparatus can capture a tomographic image of a desired site in the anterior eye portion 100-1 of the eye 100 to be examined.

  FIG. 3 shows a state in which the eye to be examined 100 is irradiated with the measurement light 201 and the anterior eye portion 100-1 is scanned in the x direction. A line sensor 184 captures information on a predetermined number of images from the imaging range in the x direction in the anterior segment 100-1. The luminance distribution on the line sensor 184 obtained at a certain position in the x direction is subjected to a fast Fourier transform (FFT), and the linear luminance distribution obtained by the FFT is converted into density or color information in order to show on the monitor. This is called an A-scan image. That is, image acquisition as an A-scan image is performed according to the output signal obtained by the interference light received by the line sensor 184 as a light receiving element. A two-dimensional image in which the plurality of A-scan images are arranged is referred to as a B-scan image. After imaging a plurality of A scan images for constructing one B scan image, the scan position in the y direction is moved and the scan in the x direction is performed again to obtain a plurality of B scan images. By displaying a plurality of B-scan images or a three-dimensional tomographic image constructed from a plurality of B-scan images on a monitor, the examiner can use it for diagnosis of the eye to be examined.

  Here, the angle of view, which is the imaging range when obtaining the anterior segment tomographic image, is normally determined according to the scan range R0 in the x direction shown in FIG. The scan range R0 is determined by the scan angle θ of the scanner and the photographing distance P0 from the objective lens 101-1 to the anterior eye portion to be examined. That is, when it is desired to change the imaging area, the scan angle θ or the imaging distance P0 is changed, but the imaging distance P0 is changed by changing the optical path length of the measurement light, for example, by moving the optical head 900 in the Z-axis direction. Can be executed more easily. Therefore, in the present invention, the optical head 900 changes the photographing distance P0 by changing the optical path length of the measuring light, and these configurations are defined as measuring optical path length changing means. In addition, although the structure which changes the optical path length of measurement light exists besides this illustrated embodiment, in this invention, it defines as a concept which includes these as a measurement optical path length change means.

In order to obtain the desired interference by combining the measurement light and the reference light, it is necessary to interlock the optical path length of the measurement light and the optical path length of the reference light so as to satisfy a predetermined condition as described above. . Accordingly, the reference mirror 119 is moved so as to change the optical path length of the reference light in accordance with the optical path length of the measurement light at the anterior segment position where the photographing distance P0 is obtained.

  The reference mirror 119 and the configuration for moving the reference mirror 119 are shown as an example of a reference light optical path length changing unit that changes the optical path length of the reference light in the present invention. Further, as described above, in order to obtain interference from the combined light, the optical path length of the reference light needs to be changed according to the optical path length of the measurement light. In the present invention, as an example, the module region functioning as the control unit in the personal computer 925 causes the reference light optical path length changing unit to link the optical path length of the reference light in conjunction with the change of the optical path length of the measuring light by the measuring light optical path length changing unit. The change is to be executed.

  FIG. 4 shows a diagram showing a scan range at the anterior ocular segment imaging position when the imaging distance P0 is changed, and a tomographic image displayed within the angle of view at that time. By changing the shooting distance P0 and moving the reference mirror 119 according to this change, the anterior ocular segment imaging range can be changed without changing the scan angle θ. As shown in FIG. 4B, the imaging distance is changed to Pmax so that the distance between the eye to be examined and the apparatus is increased, and the reference mirror 119 is moved to a position corresponding to the imaging distance Pmax, so that the anterior eye part is wide in the scan range. Imaging can be performed at Rmax (field angle). Further, as shown in FIG. 4C, the imaging distance is changed to Pmin so as to make the distance between the eye to be examined and the apparatus closer, and the reference mirror 119 is moved to a position corresponding to the imaging distance Pmin, thereby enlarging the anterior eye portion. An image can be captured within the scan range Rmin.

(Measurement screen)
FIG. 5 shows a measurement screen 1000.
1101 is an anterior eye observation screen obtained by the anterior eye observation CCD 105, and 1301 is a tomographic image display screen for confirming the acquired tomographic image.

  Reference numeral 1001 denotes a button for switching between the left and right eyes of the eye to be examined. By pressing the L and R buttons, the optical head 900 is moved to the initial position of the left and right eyes. Reference numeral 1002 denotes a mouse cursor, and the examiner moves the mouse cursor position by operating a mouse included in the input unit 929. This measuring apparatus is configured such that the alignment means can be changed according to the position of the mouse cursor by the position detection means of the mouse cursor. The mouse cursor position detecting means calculates the position from the pixel position on the display screen of the mouse cursor. A range is provided in the measurement screen, and the correspondence between the provided range and the alignment drive is set in advance. As a result, when the mouse cursor is within the set range of pixels, the alignment determined by the set range can be performed. The alignment operation by the mouse is performed by rotating the mouse wheel.

  A slider arranged in the vicinity of each image is used for adjustment. A slider 1103 designates an imaging distance with respect to the eye to be examined, and the size of the character 1003 in the anterior eye observation screen is changed in conjunction with the movement of the slider. Further, the size of the character 1003 is linked to the anterior segment imaging range (view angle), and the anterior segment observation focus lens (focusing lens) 107 is moved to a predetermined position. The focus lens 107 is shown as an example of an anterior ocular segment observation unit including a second focus lens that performs focusing on the anterior ocular segment in the present invention. The upper limit of the slider corresponds to the anterior ocular segment imaging range Rmax, and the lower limit of the slider corresponds to the anterior ocular segment imaging range Rmin. A slider 1203 performs OCT focus adjustment. The OCT focus adjustment is an adjustment for moving the lens 115 in the direction shown in the drawing in order to adjust the focus on the anterior segment. In addition, these sliders move in association with each other during the alignment operation with the mouse in each image. That is, it is independent or linked with OCT focus adjustment by the slider 1203, and the control means in the personal computer 925 performs focusing on the anterior eye part in conjunction with the change of the optical path length of the measuring light by the measuring optical path length changing means. The OCT focus lens 115 is executed. It should be noted that the focusing operation for the anterior segment by the anterior segment observation means needs to be performed according to the change in the optical path length of the measurement light accompanied by the change in the photographing distance. In the present invention, the control means described above causes the anterior eye portion to be focused by the anterior eye portion observing means in conjunction with the change of the optical path length of the measuring light by the measuring light optical path length changing means.

  Next, a tomographic image acquisition method and processing method using the OCT apparatus, which is a feature of the present embodiment, will be described with reference to FIGS. 1, 2, and 6. FIG. 7 is a flowchart showing the operations of the examiner and the personal computer 925.

  An anterior segment illumination light (not shown) illuminates the eye 100, and then the reflected light passes through the objective lenses 101-1 and 101-2, passes through the optical path L <b> 2 described above, and forms an image on the CCD 105. The anterior segment image formed on the CCD 105 is read out by a CCD control unit (not shown), amplified, A / D converted, and input to the calculation unit. The anterior eye image input to the calculation unit is taken into the personal computer 925.

  Hereinafter, the flowchart will be described with reference to FIG. In step S102, the personal computer 925 acquires the anterior segment image 1102. In step S103, when the examiner designates the change to the desired imaging range by the input unit 929 that gives an instruction to the personal computer for the anterior segment image by the slider 1103 described above, the imaging distance corresponding to the imaging range is set. Thus, the optical head 900 is moved. In response to a predetermined change in the optical path length of the measurement light accompanying the movement of the optical head 900, the reference mirror 119, the OCT focus lens 115, and the anterior eye focus lens 107 are moved to positions corresponding to the measurement optical path length in step S104. Move each. Here, the movement of each of the OCT focus lens 115 and the anterior segment focus lens 107 as the second focus lens may be interlocked by the control means. At the same time, an anterior segment tomogram 1301 is obtained by the above-described tomographic imaging method. That is, the coherence gate is adjusted so that the anterior segment image 1102 is arranged in the imaging frame, and when the change of the imaging range is instructed thereafter, the optical head 900 and the reference mirror 119 are interlocked to perform the focusing operation. Is done. After the examiner finishes alignment of the anterior eye part and the apparatus in step S105, the slider 1203 is moved in step 106. Then, the OCT focus lens 115 is operated to perform detailed focusing while viewing the anterior ocular segment tomographic image 1301, and in step 107, the imaging button 1005 is pressed to acquire a tomographic image of the anterior ocular segment. In step 108, the acquired image is displayed or the image is corrected and displayed. Here, the image acquired in step 108 is, for example, an image of a wider area or an image of a narrower area within the same size screen than the tomographic image obtained at the standard imaging distance P0. It may be. As will be described later, the correction is an operation for enlarging or reducing the display range (view angle) so that the region in these captured images is displayed with the same size as the region obtained at the imaging distance P0. . The above operation is executed by the module area functioning as an image correction means for correcting and changing the image display style in the personal computer 925. The display of the cursor or the like for instructing the change of the size of the photographing range on the display means or the display form thereof is executed by the module area functioning as the display control means included in the control means.

  Actually, the tomographic image of the anterior segment is narrowed only in the left-right direction without changing the tomographic depth if the photographing distance is farther than the standard distance, and widened only in the left-right direction if the photographing distance is narrower than the standard distance. FIG. 8 shows an example in which the display image of the anterior segment tomogram is corrected. In FIG. 8 (1a), the horizontal field of view x0 corresponding to the shooting distance P0 is narrowed to the horizontal field of view xm as the shooting distance Pmax is increased. As shown in FIG. 8 (2b), it is possible to easily convert the horizontal visual field xm into the visual field x0 and display it by a known image processing method. The shooting distance Pmin can also be processed and displayed as shown in FIG. 8 (3b). Further, various measurements may be performed based on the images of FIGS. 8 (2b) and 8 (3b), and FIG. 8 (2a) and FIG. Various measurements may be performed using the original drawing 8 (3a).

  Further, as shown in FIG. 6, the imaging range may be changed without acquiring the anterior segment image by using the slider 1103 as the imaging range selection button 1004 without acquiring the anterior segment image. In FIG. 7, the standard (R0 = 6 mm), maximum (Rmax = 9 mm), and minimum (Rmin = 3 mm) are set.

In step 105, the pupil position of the subject eye 100 is detected from the anterior eye image captured by the CCD 105 by image processing, and the alignment positional relationship between the optical tomographic imaging apparatus and the subject eye 100 can be known. The present optical tomographic imaging apparatus drives the optical head 900 to an XYZ stage (not shown) so that the detected pupil position of the eye 100 to be detected becomes an ideal position.
In addition, even during tomographic imaging, the anterior segment of the eye 100 to be examined can always be monitored.

  As described above, in the optical tomographic imaging apparatus according to the present embodiment, it is possible to provide an apparatus that allows an examiner to specify various imaging ranges and perform imaging. For example, since the examiner can set various imaging ranges by variably setting the imaging distance between the anterior segment and the optical tomographic imaging apparatus, the examiner can quickly obtain a desired anterior segment OCT image. As a result, it is possible to reduce the burden on the subject and the operator, and to carry out a suitable ophthalmic treatment. In addition, it is possible to provide an optical tomographic imaging apparatus having various fields of view and high resolution while maintaining the performance of the optical system. At the same time, since the working distance between the eye and the device can be changed, the burden on the subject can be reduced by taking an image with a longer working distance according to the condition of the subject.

  When attempting to obtain a tomographic image of a desired part in the anterior segment, usually, the fixation lamp is moved to obtain a state in which the desired part exists in the part corresponding to the imaging position, and a more appropriate alignment is obtained. It is necessary to obtain a focus state. In this case, it is inevitable that a burden imposed on the subject in order to obtain the obtained state or difficulty in operation will occur. Further, as another aspect, it may be possible to cut out a desired part from the captured tomographic image and electronically sharpen it. However, a reduction in resolution accompanying enlargement and an increase in time required for sharpening are inevitable.

For this reason, when acquiring a tomographic image of an inspection object such as an eye to be examined, it is desired to change the size of the imaging range of the tomographic image. At this time, a method of changing the optical path length of the measurement light by moving the apparatus main body in the optical axis direction with respect to the object to be inspected can be considered. In this method, the examiner does not easily know how much the optical path length of the measurement light is changed to obtain the tomographic image with the intended size.
According to this embodiment, if the examiner indicates the size of the imaging range of the tomographic image of the object to be inspected, a tomographic image having the intended size can be easily acquired.

[Other Examples]
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.
The present invention is not limited to the above-described embodiments, and various modifications and changes can be made without departing from the spirit of the present invention. For example, in the above embodiment, the case where the object to be measured is the eye is described, but the present invention can also be applied to the object to be measured such as skin or organ other than the eye. In this case, the present invention has an aspect as a medical device such as an endoscope other than the ophthalmologic apparatus. Therefore, it is preferable that the above-described eye to be examined is understood as an object to be examined.

100 eye to be examined 115 OCT focus lens 119 reference mirror 180 spectroscope 200 optical tomographic imaging apparatus 900 optical head 925 control unit 950 stage unit 1000 measurement screen

Claims (23)

An optical tomographic imaging apparatus that obtains a tomographic image of the anterior segment based on light obtained by combining return light from the anterior segment of the subject eye irradiated with measurement light and reference light corresponding to the measurement beam. And
Measuring light path length changing means for changing the optical path length of the measuring light;
Display control means for causing a display means to display a display form for receiving an instruction of the size of the imaging range of the tomographic image;
Control means for controlling the measuring optical path length changing means in accordance with an instruction received by the display form;
An optical tomographic imaging apparatus comprising:   The optical tomography apparatus according to claim 1, wherein the display form receives the instruction by an operation on an operation unit.   The optical tomography apparatus according to claim 2, wherein the operation unit is a mouse. The display form is a slider,
4. The optical tomographic imaging apparatus according to claim 1, wherein the control unit controls the measurement optical path length changing unit according to the movement of the slider. 5. The display form is a plurality of selectable buttons,
4. The optical tomography according to claim 1, wherein the control unit controls the measurement optical path length changing unit in response to selection of any one of the plurality of buttons. 5. Imaging device. The measurement light path length changing means has an optical part moving mechanism that moves an optical part including the optical path of the measurement light with respect to the anterior eye part,
The optical tomographic imaging apparatus according to claim 1, wherein the control unit controls the optical unit moving mechanism in accordance with an instruction received by the display form. Reference light path length changing means for changing the optical path length of the reference light is further included,
7. The control device according to claim 1, wherein the control means controls the measurement light optical path length changing means and the reference light optical path length changing means in conjunction with each other according to an instruction received by the display form. The optical tomographic imaging apparatus according to claim 1. A moving unit that moves a focusing lens that focuses the measurement light with respect to the anterior eye portion along an optical path;
8. The control device according to claim 1, wherein the control unit controls the measurement light path length changing unit and the moving unit in conjunction with each other according to an instruction received by the display form. The optical tomographic imaging apparatus described. A focusing lens for anterior ocular segment observation that focuses the anterior ocular segment observation light with respect to the anterior ocular segment, and an anterior ocular segment observation lens that moves the focusing lens for observing the anterior ocular segment along an optical path. Moving means, and having an anterior ocular segment observation means for observing the anterior ocular segment,
9. The control unit according to claim 8, wherein the control unit controls the measurement light path length changing unit and the moving unit for observing the anterior segment in conjunction with each other according to an instruction received by the display form. Optical tomography system. An optical tomographic imaging apparatus that obtains a tomographic image of the anterior segment based on light obtained by combining return light from the anterior segment of the subject eye irradiated with measurement light and reference light corresponding to the measurement beam. And
Measuring light path length changing means for changing the optical path length of the measuring light;
Instruction means for instructing the size of the imaging range of the tomographic image;
Control means for controlling the measuring optical path length changing means in response to an instruction by the instruction means;
An optical tomographic imaging apparatus comprising:   The control means is configured to shorten the optical path length of the measurement light when instructed to narrow the imaging range, and to increase the optical path length of the measurement light when widening the imaging range. The optical tomographic imaging apparatus according to any one of claims 1 to 10, wherein a measuring optical path length changing unit is controlled. Control of an optical tomographic imaging apparatus that acquires a tomographic image of the anterior eye part based on light obtained by combining return light from the anterior eye part of the subject eye irradiated with measurement light and reference light corresponding to the measurement light A method,
Displaying a display form for receiving an instruction of the size of the imaging range of the tomographic image on a display unit;
Changing the optical path length of the measurement light according to the instruction received by the display form;
A method for controlling an optical tomographic imaging apparatus.   The method of controlling an optical tomography apparatus according to claim 12, wherein the display form receives the instruction by an operation on an operation unit.   The method for controlling an optical tomographic imaging apparatus according to claim 13, wherein the operation means is a mouse. The display form is a slider,
15. The method of controlling an optical tomographic imaging apparatus according to claim 12, wherein the change of the optical path length of the measurement light is performed according to the movement of the slider. The display form is a plurality of selectable buttons,
The control of the optical tomography apparatus according to claim 12, wherein the change of the optical path length of the measurement light is performed in response to selection of any one of the plurality of buttons. Method. The change of the optical path length of the measurement light is performed by moving an optical part including the optical path of the measurement light with respect to the anterior eye part,
The method for controlling an optical tomographic imaging apparatus according to claim 12, wherein the step of moving the optical unit is performed according to an instruction received by the display form.   In the step of changing the optical path length of the measurement light, the change of the optical path length of the measurement light and the change of the optical path length of the reference light are performed in conjunction with each other according to an instruction received by the display form. A method for controlling an optical tomographic imaging apparatus according to any one of claims 12 to 17.   In the step of changing the optical path length of the measurement light, a focusing lens that focuses the measurement light on the change of the optical path length of the measurement light and the anterior eye according to the instruction received by the display form 19. The method for controlling an optical tomographic imaging apparatus according to claim 12, wherein movement along the optical path is performed in conjunction with each other. Moving the focusing lens for anterior ocular segment observation focusing the anterior ocular segment observation light with respect to the anterior ocular segment along an optical path, and observing the anterior ocular segment,
In the step of changing the optical path length of the measurement light, the change of the optical path length of the measurement light and the movement of the focusing lens for observing the anterior segment are performed in accordance with an instruction received by the display form. The method for controlling an optical tomographic imaging apparatus according to claim 19, wherein: Control of an optical tomographic imaging apparatus that acquires a tomographic image of the anterior eye part based on light obtained by combining return light from the anterior eye part of the subject eye irradiated with measurement light and reference light corresponding to the measurement light A method,
Receiving an instruction of the size of the imaging range of the tomographic image;
Changing the optical path length of the measurement light according to the instruction;
A method for controlling an optical tomographic imaging apparatus. The step of changing the optical path length includes a step of reducing the optical path length of the measurement light when an instruction to narrow the imaging range is received, and the measurement light when an instruction to widen the imaging range is received. The method for controlling an optical tomographic imaging apparatus according to any one of claims 12 to 21, wherein the optical path length of the optical tomographic apparatus is increased.   A program causing a computer to execute each step of the control method for an optical tomographic imaging apparatus according to any one of claims 12 to 22.

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