JP2006212153A - Ophthalmologic photography apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable the precise detection of the information of misregister when an excellent tomogram in a direction of depth is captured and to enable the reflection of the information to acquire the above information on the tomogram. <P>SOLUTION: An ophthalmologic photography apparatus having an OCT optical system to capture the tomogram of an examinee's eye using the low coherent light is equipped with a scanning means to scan the measurement light in a prescribed direction, a tomogram capturing means to capture the tomogram in the direction of the depth of the examinee's eye by changing the optical path length during the scanning by the scanning means, a switch to output a trigger to start the operations of the scanning means and the tomogram capturing means, a front image capturing means to capture two or more front images of the fundus of the eye or the anterior of the eye section in a time series, a misregister detecting means to detect the amount of the misregister of the examinee's eye, and a display control means which corrects the tomogram captured by the tomogram capturing means on the basis of the amount of the misregister to display on a monitor or displays the information of the misregister together with the tomogram captured by the tomogram capturing means on the monitor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ophthalmologic photographing apparatus that acquires a cross-sectional image of an eye to be examined using low coherent light.

An optical coherence tomography (OCT) using low-coherent light is known as an ophthalmologic imaging apparatus that can obtain a tomographic image of a subject's eye (for example, the fundus of the subject's eye) non-invasively. Such an ophthalmologic photographing apparatus scans the fundus two-dimensionally with the galvano mirror in a two-dimensional manner, and generates an OCT image two-dimensionally using an interference signal obtained when the optical path of the reference mirror coincides with the coherence length. A method for obtaining a retinal tomographic image (B-Scan) can be used by obtaining a retinal tomographic image by changing the optical path length of the reference mirror by one-dimensionally scanning the fundus with measurement light. When such an OCT image is obtained, if the eye to be inspected moves due to eye movements or the like during measurement, the measurement site is displaced and a good tomographic image cannot be obtained. In order to improve this, a scanning laser ophthalmoscope (SLO optical system) is combined with the OCT optical system, and the measurement reflected light from the eye to be examined is divided by a half mirror, and the OCT image and fundus observation image (SLO image) An apparatus is known that can detect microscopic movements of the eye by simultaneously capturing the movements, and perform positional deviation correction using the movement (see Patent Document 1).
US Pat. No. 5,975,697

  In the apparatus disclosed in Patent Document 1, misalignment correction at the time of OCT image acquisition by the C-Scan method can be performed satisfactorily, but at the time of OCT image acquisition by the B-Scan method, the SLO optical system is only one-dimensional. Therefore, it is difficult to accurately detect the shift of the measurement site due to the fixation fine movement.

  In view of the above problems, the present invention can accurately detect misalignment information when acquiring a cross-sectional image in a good depth direction, and can reflect the acquired information in the cross-sectional image. It is a technical problem to provide a simple ophthalmologic photographing apparatus.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) irradiating a part of light with low coherent length toward the eye to be examined and using part of the light with low coherent length as reference light, and the reflected light of the measurement light irradiated on the eye to be examined and In an ophthalmologic photographing apparatus that obtains an eye image to be examined by receiving interference light obtained by combining the scanning light, scanning means for scanning the measurement light in a predetermined direction, and scanning of the measurement light by the scanning means Cross-sectional image acquisition means for obtaining a cross-sectional image in the depth direction of the eye to be examined by changing the optical path length, an imaging switch for outputting a trigger signal that triggers the operation of the scanning means and the cross-sectional image acquisition means, and the imaging switch Front image acquisition means for obtaining a plurality of front images of the fundus or anterior eye portion of the eye to be examined in time series corresponding to the scanning of the measurement light by the scanning means based on the trigger signal by the scanning means, and the trigger signal A misregistration detecting unit configured to detect a misregistration amount by setting a reference image from the front image obtained by the front image obtaining unit based on the image and comparing the reference image with a front image obtained thereafter by image processing; The cross-sectional image acquired by the cross-sectional image acquisition unit is corrected based on the positional deviation amount detected by the detection unit and displayed on a monitor, or the positional deviation information is acquired by the cross-sectional image acquisition unit. Display control means for displaying on a monitor together with the cross-sectional image.
(2) In the ophthalmologic photographing apparatus according to (1), the reference image set by the detection unit is a first front image obtained by the front image acquisition unit based on the trigger signal.
(3) In the ophthalmologic photographing apparatus according to (1), the front image acquisition means receives an illumination optical system for illuminating the eye to be examined and reflected light from the eye to be illuminated illuminated by the illumination optical system to receive the eye to be examined. An imaging optical system for acquiring a front image of the optical system, wherein the measurement light is coaxial with illumination light emitted from the illumination optical system by an optical member disposed on the test side with respect to the scanning unit, and The optical member is disposed in the photographing optical system not including the illumination optical system.
(4) In the ophthalmologic photographing apparatus according to (3), the cross-sectional image acquired by the cross-sectional image acquisition unit is a fundus cross-sectional image of the eye to be examined, and the front image acquired by the front image acquisition unit is of the eye to be examined. It is a fundus image.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to detect the positional offset information at the time of acquiring the cross-sectional image of a favorable depth direction, the information which acquired the information can be reflected on a cross-sectional image.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an optical system and a control system of the ophthalmologic photographing apparatus according to the present embodiment. In this embodiment, the depth direction of the eye to be examined is the Z direction (optical axis L1 direction), the horizontal component on the plane perpendicular to the depth direction (the same plane as the face of the subject) is the X direction, and the vertical direction. The component is described as the Y direction.

  In FIG. 1, the optical system includes a tomographic measurement optical system (hereinafter referred to as an OCT optical system) 21 for non-invasively obtaining a tomographic image of the eye to be examined (for example, the fundus of the eye to be examined) and the eye to be examined in the XY directions. In order to detect the amount of displacement, the eye is roughly divided into an observation optical system 11 that observes the eye to be examined (the eye fundus, anterior eye portion, etc.) from the front. In the present embodiment, the observation optical system 11 is configured to be able to observe the fundus of the subject's eye from the front. The observation illumination optical system 11a illuminates the fundus and the fundus illuminated by the illumination optical system 11a. The observation light receiving optical system 11b receives reflected light from the light.

  The illumination optical system 11a includes an observation light source 1, an infrared filter 2 that transmits near-infrared light (for example, a wavelength of 850 nm or more), a condenser lens 3, a ring slit 4 having a ring-shaped opening, a relay lens 5, a mirror 6, A black spot plate 7 having a black spot at the center, a relay lens 8, a perforated mirror 9, and an objective lens 10 are provided. The ring slit 4 is disposed at a position conjugate with the pupil of the eye E to be examined, and illuminates the fundus of the eye to be examined by entering fundus illumination light from the periphery of the pupil.

  The light receiving optical system 11 b includes an objective lens 10, a photographing aperture 12 located in the vicinity of the aperture of the perforated mirror 9, a focusing lens 13 movable in the optical axis direction, an imaging lens 14, and a two-dimensional light receiving element 15. The photographing aperture 12 is disposed at a position substantially conjugate with the pupil with respect to the lens 10. A dichroic mirror 40 is arranged between the photographing aperture 12 and the focusing lens 13 so that the optical axis L1 of the observation optical system 11 and the optical axis L2 of the OCT optical system 21 are coaxial. The dichroic mirror 40 has a characteristic of reflecting the measurement light for tomographic acquisition used in the OCT optical system 21 and transmitting the fundus reflection light illuminated by the observation light source 1 of the illumination optical system 11a. As a result, useless noise is not included in the light receiving systems of both the OCT optical system 21 and the observation optical system 11, so that the S / N ratio does not deteriorate. The relationship between reflection and transmission may be reversed (transmit OCT measurement light and reflect observation light). The dichroic mirror 40 is preferably arranged on the light receiving element 15 side with respect to the perforated mirror 9. This is to prevent the illumination light from the illumination light source 1 toward the eye E to be reflected from the dichroic mirror 40 and unnecessary noise light from entering the light receiving element 15. In this embodiment, the dichroic mirror 40 is used. However, the present invention is not limited to this. The OCT measurement light and the observation light beam for observing the eye to be inspected may be divided. For example, a half mirror may be used. Good.

  The light beam emitted from the light source 1 is converted into an infrared light beam by the infrared filter 2 and illuminates the lens 3 and the ring slit 4. The light transmitted through the ring slit 4 reaches the perforated mirror 9 through the lens 5, the mirror 6, the black spot plate 7, and the lens 8. The light reflected by the perforated mirror 9 is once converged in the vicinity of the pupil of the eye E by the objective lens 10, and then diffused to illuminate the fundus of the eye to be examined.

  The reflected light from the fundus illuminated by the observation illumination light passes through the objective lens 10, the aperture of the perforated mirror 9, and the imaging aperture 12, passes through the dichroic mirror 40, and then passes through the lens 13 and the imaging lens 14. Then, an image is formed on the two-dimensional light receiving element 15.

  The control unit 70 stores a reference fundus image in advance in the memory 72 from the fundus image output from the two-dimensional light receiving element 15, and compares the reference fundus image and the fundus image acquired thereafter by image processing. Based on the change in position, the positional deviation of the fundus image in the XY directions is detected. In this way, the control unit 70 can calculate the direction and the amount of deviation when the eye to be examined moves due to eye movements or the like during measurement, so that the deviation of the measurement site in the XY directions can be detected. it can. The image signal detected by the two-dimensional light receiving element 15 can be observed on the monitor 75 in real time. The monitor 75 displays the acquired tomogram and various setting screens. The monitor 75 may be an external monitor provided in a personal computer or the like.

  The control unit 70 is connected to a switch unit 74 that is operated and input by an examiner. The measurement start switch 74a for starting acquisition of a tomographic image and a measurement position setting switch for setting a measurement position of an OCT image. 74b, etc. Note that the switch unit 74 may use a keyboard, a mouse, or the like provided in a personal computer or the like.

  Next, the configuration of the OCT optical system 21 provided on the reflection side of the dichroic mirror 40 will be described. Reference numeral 27 denotes an OCT light source that emits low-coherent light used as measurement light and reference light of the OCT optical system 21. For example, an SLD light source or the like is used. For the OCT light source 27, for example, a light source having a central wavelength of any one of 800 nm to 850 nm is used. Reference numeral 26 denotes a fiber coupler that doubles as a light splitting member and a light coupling member. The light emitted from the OCT light source 27 is split into reference light and measurement light by the fiber coupler 26 via an optical fiber 38a as a light guide. Therefore, the measurement light goes to the eye E through the optical fiber 38b, and the reference light goes to the reference mirror 31 through the optical fiber 38c.

  On the side that emits the measurement light toward the eye E, an end 39b of the optical fiber 38b that emits the measurement light, the relay lens 24 that can move in the optical axis direction according to the refraction error of the eye to be examined, and a galvano drive mechanism A galvanometer mirror 23 and a relay lens 22 that can scan the measurement light at high speed on the fundus in the XY directions by driving 51 are disposed. Further, the dichroic mirror 40 and the objective lens 10 serve as a light guide optical system that guides the OCT measurement light from the OCT optical system 21 to the fundus of the eye to be examined. Note that the end 39b of the optical fiber 38b is disposed so as to be conjugate with the fundus of the eye to be examined. The reflection surface of the galvanometer mirror 19 is arranged at a position conjugate with the imaging aperture 11 and the eye pupil to be examined.

  The measurement light emitted from the end 39 b of the optical fiber 38 b reaches the galvano mirror 23 via the relay lens 24, and the reflection direction is changed by driving the galvano mirror 23. Then, the measurement light reflected by the galvanometer mirror 23 is reflected by the dichroic mirror 40 via the relay lens 22, and then collected on the fundus of the eye to be examined via the photographing aperture 12, the perforated mirror 9, and the objective lens 10. Lighted.

  Then, the measurement light reflected from the fundus is reflected by the dichroic mirror 40 via the objective lens 10 to the photographing aperture 12, and directed to the OCT optical system 21, via the relay lens 22, the galvano mirror 23, and the relay lens 24. The light enters the end 39b of the optical fiber 38b. The measurement light incident on the end 39b reaches the fiber coupler 34 via the optical fiber 38b, the fiber coupler 26, and the optical fiber 38d.

  On the other hand, on the side where the reference light is emitted toward the reference mirror 31, the end 39c of the optical fiber 38c that emits the reference light, the collimator lens 29, the reference mirror 31 that turns back the traveling direction of the reference light, the condensing lens 32, An end 39e of the optical fiber 38e on which the reference light enters is disposed. The reference mirror 31 is configured to be movable in the optical axis direction by the reference mirror drive mechanism 50 in order to change the optical path length of the reference light. The reference mirror 31 includes a mirror 31a and a mirror 31b.

  The reference light emitted from the end 39c of the optical fiber 38c is converted into a parallel light beam by the collimator lens 29, reflected by the mirror 31a and the mirror 31b constituting the reference mirror 31, and then condensed by the condenser lens 32 to be optical fiber. The light enters the end portion 39e of 38e. The reference light incident on the end 39e reaches the fiber coupler 34 via the optical fiber 38e.

  Here, since the measurement light is reflected by each layer of the fundus oculi and becomes reflected measurement light having a different time delay and different intensity, and merges with the reference light by the fiber coupler 34, the interference phenomenon of these two lights is Utilizing this, the intensity of the reflected measurement light is detected by the light receiving element 35, and the reference mirror 31 is moved (scanned) in the optical axis direction, whereby a reflection intensity distribution in the optical axis direction can be obtained. Furthermore, a tomographic image on the XZ plane or YZ plane of the fundus of the eye to be examined can be acquired by scanning the measurement light in the X direction or Y direction on the fundus with the galvanometer mirror 23 (in this embodiment, in this way, A method of obtaining a retinal tomographic image by scanning the measurement light with respect to the fundus one-dimensionally and changing the optical path length of the reference mirror is referred to as B-scan). Furthermore, it is also possible to obtain a fundus image (XY plane) two-dimensionally by scanning the measurement light two-dimensionally in the XY direction with the reference mirror 31 fixed (in the present embodiment, The method of scanning the fundus two-dimensionally with respect to the fundus and obtaining an OCT image two-dimensionally with an interference signal obtained when the optical path of the reference mirror coincides with the coherence length is referred to as C-scan). Furthermore, if these are used to scan the fundus in two dimensions while moving the reference mirror 31 in the optical axis direction, it is possible to construct a three-dimensional image of the fundus. The tomographic image acquired in this way is displayed on the monitor 75.

  The operation of the apparatus having the above configuration will be described. First, the examiner operates a joystick (not shown) so that the fundus image of the subject's eye is displayed on the monitor 75, and causes the subject to fix an internal fixation target (not shown). After the fundus image of the measurement site desired by the examiner is displayed on the monitor 75 in this way, when focusing is performed, the process proceeds to a step for acquiring (imaging) a tomographic image. In the present embodiment, a case where a tomographic image of the XZ plane is acquired by the B scan method will be described.

FIG. 2 is an example of a fundus image displayed on the monitor 75. First, the examiner selects the position of the tomographic image that the examiner wants to acquire from the fundus image observed in real time. The examiner operates the measurement position setting switch 74b to move the line L1 representing the measurement position in the X direction with respect to the fundus observation image, and sets the measurement position in the X direction. If the line L1 is set to be in the X direction, a tomographic image of the XZ plane is acquired, and if the line L1 is set to be in the Y direction, a tomographic image of the YZ plane is performed. ing.

  The examiner sets the measurement position in the Z direction as well as the measurement position in the X direction (Y direction). In the Z direction, the scanning width of the measuring light in the Z direction (for example, 3 mm) and the number of scanning steps (the number of measured sheets in the Z direction) are set. For example, if the scanning width is 3 mm and the number of scanning steps is set to 10 μm, a tomographic image having a depth of 3 mm and a 10 μm step is obtained. It should be noted that the longer the scan width and the smaller the number of scan steps, the longer it takes to acquire a tomographic image.

In this way, when the setting of the measurement position is completed and the examiner inputs the measurement start switch 74a, the control unit 70 starts the XZ plane tomographic image acquisition operation by the B scan. here,
The control unit 70 starts driving the galvanometer mirror 23 so that the set measurement position is irradiated with the measurement light, and also starts detecting the positional deviation of the fundus image in the XY directions. In this case, for example, a method may be considered in which the fundus image when the measurement start switch 74a is input is stored in the memory 72 as a reference fundus image, and the positional displacement of the fundus image is obtained by image processing based on this.

  The control unit 70 drives the galvano drive mechanism 51 to control the reflection surface of the galvano mirror 23 to scan the measurement light irradiation position in the X direction and to drive the reference mirror drive mechanism 50 with a predetermined number of scanning steps. The reference mirror 31 is moved in the direction of the optical axis so that the above image can be obtained. In addition, the control unit 70 detects the positional deviation of the fundus image in the XY directions in time series, and stores the detected positional deviation amount and the scanning of the measurement light in the memory 72 in association with each other.

  In this manner, the light receiving element 35 detects the reflected measurement light from the fundus at the optical path length corresponding to the position of the reference mirror 31, and the control unit 70 determines the reflection intensity distribution in the X direction of the measurement light at the optical path length. get. Furthermore, when the reference mirror 31 moves in the optical axis direction, the control unit 70 acquires the reflection intensity distribution in the XZ direction. In this way, when the optical path length of the reference light reaches the preset scanning width of the measuring light in the Z direction, the measurement is terminated and the measurement result is displayed on the monitor 75.

  Here, the control unit 70 constructs a tomographic image in the XZ direction by well-known image processing based on the obtained reflection intensity distribution in the XZ direction. In this embodiment, the control unit 70 has a shape corresponding to the scanning of the measurement light. Thus, based on the positional deviation amount of the fundus image stored in the memory 72 in the X direction, the deviation amount of the measurement site in the X direction is obtained, and the tomographic image is corrected by image processing. Further, the amount of deviation of the measurement site in the Y direction is obtained based on the amount of positional deviation in the Y direction of the fundus image, and it is determined whether or not the measurement was properly performed at the measurement site selected in advance.

  First, correction of a tomographic image in the X direction will be described with reference to FIG. FIG. 3A is a schematic diagram showing the shift of the measurement site in the X direction when a tomographic image is acquired in the XZ direction. The horizontal axis represents the Z direction, which is the depth of the eye to be examined, and the vertical axis represents the deviation ΔdX of the measurement site in the X direction. FIG. 3B is a schematic diagram showing a tomographic image constructed when there is a shift in the measurement site as shown in FIG. As described above, if the eye to be examined moves in the X direction due to fixation movement or the like during acquisition of the tomographic image, the tomographic image is displaced in the X direction with respect to the preset measurement position (for example, D1 portion in the figure). ). Such a tomogram is not a good tomogram. Further, it is not appropriate for the examiner to diagnose the eye to be examined based on such a tomographic display image.

  Therefore, in this embodiment, when the control unit 70 constructs a tomographic image for each scanning step in the Z direction, it is based on the amount of positional deviation in the X direction for each scanning step stored in the memory 72. Then, correction processing is performed so that each tomographic image is positioned at the reference position. For example, when there is a shift such as ΔdX1 in the tomographic image of the D1 portion, the control unit 70 corrects the tomographic image by shifting the position of the tomographic image in the D1 portion by ΔdX1 in the X direction. By performing such correction processing on the entire tomographic image, the tomographic image in the XZ direction can obtain a tomographic image with high accuracy in which the displacement of the tomographic image in the X direction as shown in FIG. .

  Next, with respect to the Y direction, it is determined whether or not the measurement has been properly performed at the measurement site selected in advance. FIG. 4A is a schematic diagram illustrating the shift of the measurement site in the Y direction when a tomographic image is acquired in the XZ direction. The horizontal axis represents the Z direction, and the vertical axis represents the amount of deviation Δdy of the measurement site in the Y direction. FIG. 4B is a schematic diagram showing the shift of the measurement site on the fundus in the Y direction when there is a shift of the measurement site as shown in FIG. As described above, if the eye to be examined moves in the Y direction due to fixation movement or the like during acquisition of the tomographic image, the measurement light irradiation position is shifted in the Y direction. Resulting in. Thus, even if a tomographic image is constructed in a state where there is a shift in the measurement region in the Y direction, it cannot be said that the tomographic image is accurate because the measurement region is different.

  Therefore, in the present embodiment, when the control unit 70 constructs a tomographic image, an error is detected for each scanning step based on the amount of deviation of the measurement region in the Y direction for each scanning step stored in the memory 72. Information is attached, and error information is notified when a tomogram is displayed on the monitor 75. In this case, the control unit 70 determines, for each scanning step, whether or not the deviation amount of the measurement site satisfies a predetermined allowable range set in advance, and attaches error information when it is determined that an error has occurred. Then, when displaying the tomographic image, it may be displayed so as to designate the area of the tomographic image in which the measurement site has shifted as an error (see FIG. 4C), or the entire tomographic image may be displayed. It is good also as a structure displayed as an error. By performing error display on the tomographic image as described above, the examiner can know whether the tomographic image has been acquired at an appropriate measurement site, which is useful for diagnosis and the like. .

  In the display of the tomographic image on the monitor 75, a configuration may be adopted in which the tomographic image is constructed after the reflection intensity distribution of all the measurement areas in the XZ direction is acquired. A configuration may be adopted in which tomographic images including error information in a range where the measurement is completed are displayed on the monitor 75 as needed by proceeding with image processing on the received light signal as needed. If the configuration is such that the obtained tomographic image is displayed on the monitor 75 as needed, the examiner can know the error information of the measurement site as described above during measurement. Can be migrated.

In summary, when a tomographic image of the XZ plane or a tomographic image of the YZ plane is acquired by B-scan, the tomographic image correction is performed with respect to the displacement of the measurement site in the scanning direction of the measurement light based on the positional deviation amount of the eye to be examined. By processing and informing the examiner whether or not a tomographic image has been obtained at an appropriate measurement site in the non-scanning direction of the measurement light, a good tomographic image can be obtained and useful information at the time of diagnosis Can be obtained.

  In the present embodiment, the tomographic image of the fundus of the eye to be examined is obtained. However, the present invention is not limited to this, and can be applied to an ophthalmologic photographing apparatus that obtains a tomographic image of any part of the eye to be examined. (For example, to obtain a tomographic image of the anterior segment).

  In the present embodiment, the positional deviation of the eye to be examined is detected by detecting the front image of the fundus of the eye to be examined. However, the amount of positional deviation of the eye to be examined may be obtained. It is good also as a structure which detects the position shift of an eye to be examined based on the front image of an anterior eye part.

  In the present embodiment, the positional deviation amount of the eye to be examined is detected from the positional change of the entire fundus image. However, any one of the blood vessel shape and the optic disc in the fundus image is used as a feature point for detecting the positional deviation. A configuration may be adopted in which the amount of displacement is obtained from the change in position of the feature point.

  Further, the present invention can be applied to an apparatus in which a scanning laser ophthalmoscope (SLO) optical system is combined in the OCT optical system 21 (see FIG. 5). In the case of the OCT optical system of the present embodiment, for example, the OCT light source 27 is also used as the light source of the SLO optical system, and a half mirror 60 is provided between the relay lens 24 and the end 39b of the optical fiber 38b. In order to construct a confocal optical system in the reflection direction, a condensing lens 61, a confocal aperture 62 conjugate to the fundus, and a light receiving element 63 for SLO can be considered. The galvanometer mirror 23 is also used as an OCT optical system in order to scan light used for the SLO optical system in the XY directions on the fundus. In the case of such an apparatus, when a two-dimensional fundus image of the fundus is obtained by the C-scan method, it is possible to detect the shift (XY direction) of the measurement site based on the two-dimensional confocal image by the SLO optical system. However, when obtaining a cross-sectional image (XZ plane, YZ plane) in the depth direction of the eye to be examined by the B-scan method, the SLO optical system detects only in one axis direction (X direction or Y direction). It is impossible to observe in real time whether scanning is performed, and it is impossible to detect a shift of the measurement site due to microscopic fixation. That is, the measurement range of the SLO optical system is limited by the operation of the galvanometer mirror 23. Therefore, with the configuration as in the present embodiment, even when a tomographic image of the XZ plane or the YZ plane is obtained by B-scan, the measurement site of the eye to be inspected is not affected by the galvanometer mirror 23. Since it can be acquired from the front image detected by the observation optical system 11, the tomographic image correction and the error information notification can be performed in the same manner as described above.

It is a figure which shows the optical system and control system of the ophthalmologic imaging device of this embodiment. It is an example of the fundus oculi image displayed on the monitor. It is a figure explaining correction | amendment of the tomogram in a X direction. It is explanatory drawing regarding determination of whether the measurement was performed appropriately in the Y direction in the measurement site selected beforehand. It is a figure explaining the structure of the apparatus which combined the scanning laser ophthalmoscope (SLO) optical system inside the OCT optical system.

Explanation of symbols

11 Observation optical system 21 Tomographic measurement optical system (OCT optical system)
23 Galvano mirror 31 Reference mirror 35 Light receiving element 40 Dichroic mirror 70 Control unit 75 Monitor

Claims (4)

By irradiating a part of the light having a low coherent length toward the eye to be examined and using a part of the light having the low coherent length as a reference light, and by combining the reference light and the reflected light of the measurement light emitted to the eye to be examined In an ophthalmologic photographing apparatus that obtains an eye image to be examined by receiving the obtained interference light, a scanning unit that scans the measurement light in a predetermined direction, and an optical path length of the reference light during scanning of the measurement light by the scanning unit Cross-sectional image acquisition means for obtaining a cross-sectional image in the depth direction of the eye to be examined by changing, an imaging switch for outputting a trigger signal that triggers the operation of the scanning means and the cross-sectional image acquisition means, and a trigger signal by the imaging switch Based on the trigger signal, front image acquisition means for obtaining a plurality of front images of the fundus or anterior eye portion of the eye to be examined in time series corresponding to the scanning of the measurement light by the scanning means A misregistration detecting means for setting a reference image from the front image obtained by the front image obtaining means, comparing the reference image with a front image obtained thereafter by image processing, and detecting a misregistration amount; The cross-sectional image obtained by correcting the cross-sectional image acquired by the cross-sectional image acquiring unit based on the amount of positional deviation detected by the detecting unit and displaying it on a monitor, or the cross-sectional image acquired by the cross-sectional image acquiring unit. An ophthalmologic photographing apparatus comprising: display control means for displaying on a monitor together with an image. 2. The ophthalmologic photographing apparatus according to claim 1, wherein the reference image set by the detecting means is a first front image obtained by the front image obtaining means based on the trigger signal. 2. The ophthalmologic photographing apparatus according to claim 1, wherein the front image acquisition means receives an illumination optical system for illuminating the eye to be examined and reflected light from the eye to be illuminated illuminated by the illumination optical system to receive a front image of the eye to be examined. And the measurement light is coaxial with the illumination light emitted from the illumination optical system by an optical member disposed on the test side with respect to the scanning means, and the optical member Is arranged in the photographing optical system not including the illumination optical system. 4. The ophthalmologic photographing apparatus according to claim 3, wherein the cross-sectional image acquired by the cross-sectional image acquisition unit is a fundus cross-sectional image of the eye to be examined, and the front image acquired by the front image acquisition unit is a fundus image of the eye to be examined. An ophthalmologic photographing apparatus characterized by being.