JP2019202062A - Eyeground imaging apparatus and control method therefor - Google Patents

Abstract

To provide an eyeground imaging apparatus which, in focus adjustment in an OCT-SLO complex device, facilitates discrimination between a mode in which both focuses can be adjusted at the same time and a mode in which one of both focuses can be adjusted.SOLUTION: The eyeground imaging apparatus includes: an OCT optical system for acquiring tomographic information of a subject eye by using OCT measurement light; an SLO optical system for acquiring eyeground information of the subject eye by using SLO measurement light; first focus adjustment means for adjusting the focus of the OCT measurement light; second focus adjustment means for adjusting the focus of the SLO measurement light; control means for controlling the first focus adjustment means and the second focus adjustment means; selection means for selecting any mode from a first mode for controlling the first focus adjustment means in conjunction with the second focus adjustment means and a second mode for controlling one of the first focus adjustment means and the second focus adjustment means; and notification means for notifying the state of selection.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fundus imaging apparatus and a control method thereof.

  In the field of ophthalmology, optical coherence tomography (OCT: Optical Coherence Tomography) using multiwavelength lightwave interference is known. In OCT, a tomographic image of a sample (particularly the fundus) can be obtained with high resolution. Hereinafter, an apparatus for taking a tomographic image by OCT will be referred to as an OCT apparatus.

  In addition, a scanning laser opthalmoscope (SLO), which is an ophthalmologic apparatus using the principle of a confocal laser microscope, is also known. In SLO, a raster scan is performed on the fundus using a laser as measurement light, and a planar image of the fundus can be obtained with high resolution and high speed from the intensity of the return light. Hereinafter, an apparatus that captures such a planar image is referred to as an SLO apparatus.

  In recent years, as an apparatus for photographing the fundus, an apparatus for photographing the fundus by scanning measurement light, such as an OCT apparatus or an SLO apparatus, has been actively used. Further, it has become possible to acquire a retina image with improved lateral resolution by increasing the beam diameter of the measurement light in these fundus imaging apparatuses.

  However, with the increase in the diameter of the measurement light beam, in obtaining the fundus image, there is a problem that the SN ratio and the resolution of the image are reduced due to the aberration of the eye to be examined. In order to solve this problem, compensation optics having a compensation optical system that measures the aberration of the subject's eye in real time using a wavefront sensor and corrects the aberration of the measurement light generated in the subject's eye and its return light with a wavefront correction device OCT devices and adaptive optics SLO devices have been developed (Patent Document 1). By using these devices, it is possible to compensate for the aberration of the eye to be inspected due to the increase in the beam diameter of the measurement light, and it is possible to acquire an image with high lateral resolution.

  Here, in the adaptive optics OCT apparatus, when the beam diameter of the measurement light is increased in order to improve the lateral resolution, the depth of focus becomes shallow. When the depth of focus becomes shallow, the range in the depth direction in which an image with a good SN ratio is obtained is limited. Therefore, in order to acquire an image with a better S / N ratio using the adaptive optical OCT apparatus, it is important to accurately match the focal position of the OCT measurement light with the layer to be photographed on the fundus retina.

  On the other hand, in such a fundus imaging apparatus, it takes some time from the start to the end of imaging. For this reason, it becomes easy to be influenced by involuntary eye movements called fixation fixation micromotion, eye movements due to poor fixation, or facial movements, and fundus tracking for tracking the fundus movement becomes more important. In particular, in an apparatus that acquires an image with high lateral resolution, such as an adaptive optics OCT apparatus or an adaptive optics SLO apparatus, higher-accuracy fundus tracking is important.

  In Patent Document 2, the present applicant proposes a device capable of focusing OCT measurement light on a desired layer while executing accurate fundus tracking in a device in which the compensation optical OCT and the compensation optical SLO are combined. doing.

JP2015-221091A Japanese Patent Application No. 2017-239694

  In Patent Document 2, a part of the optical system of the OCT apparatus and the optical system of the SLO apparatus are used as a common optical path, and a diopter correction optical system is configured in the common optical path. One diopter correction optical system is configured. Thereby, it is possible to individually adjust the focal position of the fundus tomographic image by the OCT apparatus to match a desired layer while holding the fundus front image by the SLO apparatus at a focal position suitable for the fundus track.

  However, in imaging with a combined apparatus of an OCT apparatus and an SLO apparatus, it is preferable to individually adjust the focus of the OCT apparatus and the SLO apparatus depending on the state of the eye to be examined, the layer or region to be imaged, and the imaging flow (imaging protocol). There is a confusion between cases and cases that are not. Japanese Patent Application Laid-Open No. 2004-228561 discloses the interlocking and release of the two focus mechanisms, but does not mention the user interface related to the setting and setting state display. Therefore, there is a problem that it is not easy to grasp the interlocking state of the focus during shooting.

  An object of the present invention is to provide an apparatus that makes it easy for an operator to determine which mode is set to a mode in which adjustment of the focal position of each of the SLO device and the OCT device is linked or not. .

  A fundus imaging apparatus according to an embodiment of the present invention includes an OCT optical system that acquires tomographic information of an eye to be examined using OCT measurement light, and an SLO optical system that acquires fundus information of the eye to be examined using SLO measurement light. First focus adjustment means for adjusting the focus of the OCT measurement light, second focus adjustment means for adjusting the focus of the SLO measurement light, the first focus adjustment means, and the second focus adjustment means A first mode for controlling the first focus adjustment unit and the second focus adjustment unit in conjunction with each other, the first focus adjustment unit and the second focus adjustment. Selection means for selecting any mode from the second mode for controlling any one of the means, and notification means for notifying the selection state.

  According to the present invention, it is possible to easily determine which mode is set to the mode in which the focus adjustment of the SLO measurement light and the focus adjustment of the OCT measurement light are linked or not.

1 shows a schematic configuration of a fundus imaging apparatus according to a first embodiment. 1 schematically shows an imaging range of an OCT optical system and an SLO optical system in a fundus imaging apparatus. 3 is a flowchart illustrating a fundus imaging procedure according to the first embodiment. It is the schematic diagram which showed the screen of the control software which concerns on 1st Embodiment. It is the schematic diagram which showed the mode alerting | reporting by the display change of the button which concerns on 1st Embodiment. It is the schematic diagram which showed the example of the mode alerting | reporting which concerns on 1st Embodiment. 3 shows a schematic configuration of a fundus imaging apparatus according to a second embodiment. 6 is a flowchart illustrating a fundus photographing procedure according to the second embodiment. It is the schematic diagram which showed the screen of the control software which concerns on 2nd Embodiment. It is the schematic diagram which showed the mode alert | report by the form change of the slide bar which concerns on 2nd Embodiment. It is the schematic diagram which showed the example of the mode alerting | reporting which concerns on 2nd Embodiment. It is the schematic diagram which showed the example of the mode alerting | reporting which concerns on 2nd Embodiment. It is the schematic diagram which showed the example of the mode alerting | reporting which concerns on 2nd Embodiment. It is the schematic diagram which showed the example of the mode alerting | reporting which concerns on 2nd Embodiment.

  Hereinafter, exemplary embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, dimensions, materials, shapes, and relative positions of components described in the following embodiments are arbitrary, and can be changed according to the configuration of the apparatus to which the present invention is applied or various conditions. Also, in the drawings, the same reference numerals are used between the drawings to indicate the same or functionally similar elements.

  In the following description, the retina of the human eye is described as the inspection object, but the inspection object is not limited thereto, and for example, the anterior eye portion of the human eye may be the inspection object.

[First Embodiment]
The fundus imaging apparatus according to the first embodiment of the present invention used for acquiring an image of the fundus of the eye to be examined will be described in detail below with reference to FIGS. In this embodiment, in a fundus imaging apparatus having a focus mechanism on a common optical path of OCT and SLO and a dedicated optical path of SLO, the mode is switched between a mode in which the focus of OCT and SLO are interlocked and a mode of adjusting the focus of OCT. This is an example in which the current mode is easily understood by the examiner by performing switching according to an instruction of a button and notifying the selected mode according to the display state.

(Device configuration)
A fundus imaging apparatus 100 as one aspect of the fundus imaging apparatus according to the present embodiment will be described with reference to FIG. The fundus imaging apparatus 100 of this embodiment includes an OCT optical system, an SLO optical system, an anterior eye observation optical system, a fixation lamp optical system, a control unit 190 (control unit), a display unit 198 (display unit), and an input unit. 199 is provided. In the present embodiment, the entire optical system is mainly composed of a reflective optical system using a mirror.

  The control unit 190 may be configured using a general-purpose computer, or may be configured as a dedicated computer for the fundus imaging apparatus 100. Similarly, the display unit 198 and the input unit 199 may be configured using a general-purpose display, a mouse, and a keyboard, respectively, or may be configured as a device-dedicated monitor, an operation panel, and buttons. The control unit 190, the display unit 198, and the input unit 199 may be configured separately from the imaging unit including the OCT optical system, the SLO optical system, the anterior eye observation optical system, and the fixation lamp optical system, You may comprise integrally.

  First, the OCT optical system of the fundus imaging apparatus 100 will be described. The light source 101 is a light source for generating light (low coherent light). In this embodiment, an SLD (Super Luminescent Diode) having a center wavelength of 830 nm and a band of 50 nm is used as the light source 101. Although the SLD is selected in the present embodiment, the light source may be any light source that can emit low-coherent light, and ASE (Amplified Spontaneous Emission) or the like can also be used. The light source 101 is connected to the control unit 190 and is controlled by the control unit 190.

  Further, the wavelength of light emitted from the light source 101 can be set to a wavelength corresponding to near-infrared light in view of measuring the eye. Furthermore, since the wavelength of the light emitted from the light source 101 affects the lateral resolution of the obtained tomographic image, it can be made as short as possible. In this embodiment, the center wavelength is set to 830 nm. Other wavelengths may be selected depending on the measurement site to be observed. The wider the wavelength band, the better the resolution in the depth direction. In general, when the center wavelength is 830 nm, the resolution is 6 μm in the 50 nm band and 3 μm in the 100 nm band. The central wavelength and band of the light source 101 are not limited to this, and may be changed according to a desired configuration.

  The light emitted from the light source 101 passes through the single mode fiber 142 and is guided to the optical coupler 141 which is a light splitting unit. The light emitted from the light source 101 is divided by the optical coupler 141 at an intensity ratio of 90:10, and becomes the reference light 103 and the OCT measurement light 104, respectively. The division ratio is not limited to this, and can be appropriately selected according to the inspection object.

  Next, the optical path of the reference light 103 will be described. The reference light 103 divided by the optical coupler 141 is guided to the lens 151 through the single mode fiber 143 and emitted as parallel light. Next, the reference light 103 passes through the dispersion compensation glass 159 and is guided by the mirrors 111 and 112 to the mirror 124 which is a reference mirror. In this embodiment, a plane mirror is used as the reference mirror. The light reflected by the mirror 124 is again sequentially reflected by the mirror 112 and the mirror 111, passes through the dispersion compensation glass 159, and is guided to the optical coupler 141.

  The dispersion compensation glass 159 can compensate the reference light 103 for dispersion when the OCT measurement light 104 reciprocates between the eye E and the lens 154.

  The mirror 124 is mounted on the electric stage 125 and constitutes an optical path length adjusting means. The electric stage 125 can move in the optical axis direction of the reference light 103 as shown by an arrow, and the optical path length of the reference light 103 can be adjusted by moving the position of the mirror 124. The electric stage 125 is controlled by the control unit 190.

  Next, the optical path of the OCT measurement light 104 will be described. The OCT measurement light 104 divided by the optical coupler 141 is guided to the lens 154 via the single mode fiber 145 and emitted as parallel light.

  Next, the OCT measurement light 104 passes through the dichroic mirror 177 and the beam splitter 171, is reflected by the mirrors 113 and 114, and enters the deformable mirror 182 as aberration correction means. Here, the deformable mirror 182 corrects the aberration of the OCT measurement light 104 and the OCT return light 105 by freely deforming the mirror shape based on the aberration detected by the wavefront sensor 181 that is an aberration measurement means. It is a mirror device to be used.

  In the present embodiment, a deformable mirror is used as the aberration correction unit. However, the aberration correction unit is only required to correct the aberration, and a spatial light phase modulator using liquid crystal can also be used. In this embodiment, a Shack-Hartmann wavefront sensor 181 is used as the aberration measuring means. However, the aberration measuring means is not limited to this, and may be configured using any known sensor or the like for measuring aberration. The deformable mirror 182 and the wavefront sensor 181 are controlled by a control unit 190 which is a control unit.

  The OCT measurement light 104 is reflected by the deformable mirror 182, then reflected by the mirrors 115 and 116, and enters the dichroic mirror 173. Here, the dichroic mirrors 173 and 174 reflect the light from the light source 101 and transmit the light from the light source 102 according to the wavelength of the light.

  The OCT measurement light 104 reflected by the dichroic mirror 173 enters the X scanner 132 (second scanning means). The center of the OCT measurement light 104 is adjusted so as to coincide with the rotation center of the X scanner 132. By rotating the X scanner 132, the OCT measurement light 104 is used to set the retina Er of the eye E to be examined as the optical axis. Scan in the vertical direction. Here, a galvanometer mirror is used as the X scanner 132. The X scanner 132 may be configured by any other deflection mirror. Although not shown, the X scanner 132 is connected to the control unit 190 and is controlled by the control unit 190.

  The OCT measurement light 104 reflected by the X scanner 132 is reflected by the dichroic mirror 174 and then sequentially reflected by the mirrors 117 to 120.

  The mirrors 119 and 120 are mounted on the electric stage 126 and constitute first focusing means. The electric stage 126 can move toward or away from the mirrors 118 and 121 as shown by the arrows. The electric stage 126 is controlled by the control unit 190. The mirrors 119 and 120 are disposed in a common optical path of the OCT optical system and the SLO optical system. Therefore, the focus states of the OCT measurement light 104 and the SLO measurement light 106 can be adjusted corresponding to the diopter of the eye E by moving the mirrors 119 and 120 by the electric stage 126.

  In this embodiment, the movement range of the electric stage 126 is 160 mm, and the focus positions of the OCT measurement light 104 and the SLO measurement light 106 can be adjusted corresponding to the diopter range of −12D to + 7D of the eye E. . The moving range of the electric stage 126 may be arbitrarily set depending on a desired configuration.

  Here, in the present embodiment, the first focusing means disposed in the common optical path of the OCT optical system and the SLO optical system is configured by a Badal optical system that is a reflection optical system of the mirrors 119 and 120. By using the reflection optical system, unnecessary stray light can be prevented from entering the wavefront sensor 181, and accurate aberration measurement and aberration correction can be performed.

  The OCT measurement light 104 reflected by the mirror 120 is reflected by the mirrors 121 and 122 and enters the Y scanner 133 (first scanning means). The center of the OCT measurement light 104 is adjusted so as to coincide with the rotation center of the Y scanner 133. By rotating the Y scanner 133, the OCT measurement light 104 is used to move the optical axis on the retina Er and the X scanner 132. It is possible to scan in a direction perpendicular to the scan direction. Here, a galvanometer mirror is used as the Y scanner 133. The Y scanner 133 may be configured by any other deflection mirror.

  Although not shown, the Y scanner 133 is connected to the control unit 190 and is controlled by the control unit 190. The X scanner 132 and the Y scanner 133 constitute an OCT scanning unit that scans the OCT measurement light 104 on the fundus of the eye E in a two-dimensional direction.

  The OCT measurement light 104 reflected by the Y scanner 133 is reflected by the mirror 123, passes through the dichroic mirrors 175 and 176, and enters the eye E to be examined. The X scanner 132, the Y scanner 133, and the mirrors 117 to 123 function as an optical system for scanning the retina Er using the OCT measurement light 104. With this optical system, the retina Er can be scanned using the OCT measurement light 104 around the pupil Ep as a fulcrum.

  When the OCT measurement light 104 enters the eye E, the OCT measurement light 104 is reflected or scattered by the retina Er, returns as the OCT return light 105 through the optical path of the OCT measurement light 104, and is guided to the optical coupler 141 again.

  The reference beam 103 and the OCT return beam 105 are combined by an optical coupler 141 to become interference light. Here, when the optical path lengths of the OCT measurement light 104 and the OCT return light 105 are substantially equal to the optical path length of the reference light 103, the OCT return light 105 and the reference light 103 interfere with each other and become interference light. . The control unit 190 controls the electric stage 125 to move the mirror 124 so that the optical path length of the reference light 103 is matched with the optical path lengths of the OCT measurement light 104 and the OCT return light 105 that change depending on the measurement target part of the eye E. it can. The combined light 108 (interference light) is emitted as spatial light from the single mode fiber 144, and is guided to the transmissive grating 161 through the lens 152. Then, the light 108 is split for each wavelength by the transmission grating 161, condensed by the lens 153, and enters the line camera 191.

  The light 108 incident on the line camera 191 is converted into a voltage signal (interference signal) corresponding to the light intensity for each position (wavelength) on the line camera 191. Specifically, interference fringes in the spectral region on the wavelength axis are observed on the line camera 191. The obtained voltage signal group is converted into a digital value. The control unit 190 can generate a tomographic image that is tomographic information of the eye E by performing data processing on the interference signal converted into a digital value. The control unit 190 also serves as an information display control unit that displays the generated tomographic image (tomographic information) on the display unit 198. Note that the data processing when generating the tomographic image may be any known data processing for generating a tomographic image (tomographic information) from the interference signal.

  The single mode fibers 142 and 143 are provided with polarization adjustment paddles 183 and 184. The polarization adjustment paddles 183 and 184 can adjust the polarization of light passing through the single mode fibers 142 and 143. By using the polarization adjustment paddles 183 and 184, the polarization state of the light from the light source 101 is adjusted, or the polarization of the reference light 103 is adjusted so that the polarization states of the OCT return light 105 and the reference light 103 match. Can be. The position where the polarization adjustment paddle is provided is not limited to this, and may be provided in the single mode fiber 145 or the like.

  Incidentally, the OCT return light 105 is split by the beam splitter 171 when returning through the optical path of the OCT measurement light 104, and a part of the OCT return light 105 enters the wavefront sensor 181. The wavefront sensor 181 measures the aberration of the incident OCT return light 105. In the present embodiment, the beam splitter 171 reflects a part of the OCT return light 105 and transmits SLO return light 107 described later. Thereby, the aberration of the OCT return light 105 can be selectively measured. The wavefront sensor 181 is electrically connected to the control unit 190. The control unit 190 applies the output from the wavefront sensor 181 to the Zernike polynomial so as to grasp the aberration of the eye E measured by the wavefront sensor 181.

  The control unit 190 corrects the diopter of the eye E by controlling the positions of the mirrors 119 and 120 using the electric stage 126 for the defocus component of the Zernike polynomial. Further, the control unit 190 controls and corrects the surface shape of the deformable mirror 182 for components other than defocus. Thereby, the control unit 190 can generate (acquire) a tomographic image with high lateral resolution.

  Here, the mirrors 113 to 123 are arranged so that the pupil Ep, the X scanner 132, the Y scanner 133, the wavefront sensor 181, and the deformable mirror 182 are optically conjugate. As a result, the wavefront sensor 181 can measure the aberration of the eye E.

  Next, the SLO optical system will be described. The light source 102 is a light source for generating light having a wavelength different from that of the light source 101. In the present embodiment, an SLD having a wavelength of 780 nm is used as the light source 102. The type of the light source 102 of the SLO optical system is not limited to this, and an LD (Laser Diode) or the like can be used as the light source 102. Further, the wavelength of the light source 102 is not limited to this, and may be changed according to a desired configuration. The light source 102 is connected to the control unit 190 and is controlled by the control unit 190.

  The light emitted from the light source 102 is guided to the lens 155 and emitted as parallel light. The light transmitted through the lens 155 is guided to the beam splitter 172, and is divided at an intensity ratio of 90:10 between the transmitted light and the reflected light (SLO measurement light 106). The SLO measurement light 106 reflected by the beam splitter 172 passes through the focus lens 157 and the lens 158.

  The focus lens 157 is mounted on the electric stage 127 and constitutes a second focus unit. The electric stage 127 can move in the optical axis direction of the SLO measurement light 106 as shown by the arrow, and the focus state of the SLO measurement light 106 can be adjusted. The electric stage 127 is controlled by the control unit 190.

  The control unit 190 can adjust the focus position of the SLO measurement light 106 to a position different from the focus position of the OCT measurement light 104 by moving the focus lens 157 by controlling the electric stage 127. Here, the moving range of the electric stage 127 is 10 mm, and the moving range corresponds to a diopter range of −2D to + 2D. The moving range of the electric stage 127 is not limited to this, and may be set to an arbitrary moving range narrower than the moving range of the electric stage 126.

  In the present embodiment, the focus adjustment range of the second focus unit is narrowed because the first focus unit is used to adjust the focus of the OCT measurement light 104 and the SLO measurement light 106 to correct the diopter of the eye E. be able to. Therefore, the movement range of the electric stage 127 can be narrower than the movement range of the electric stage 126. Therefore, since the focal positions of the OCT optical system and the SLO optical system can be adjusted to different positions using a smaller stage, the optical system can be reduced in size.

  In FIG. 1, the focus lens 157 is illustrated as a convex lens, and the lens 158 is illustrated as a concave lens. However, the configurations of the focus lens 157 and the lens 158 are not limited thereto. The focus lens 157 may be a concave lens, the lens 158 may be a convex lens, or both may be convex lenses, and an intermediate image may be formed between them.

  The light transmitted through the focus lens 157 and the lens 158 goes to the dichroic mirror 177. The dichroic mirror 177 transmits light from the light source 101 and reflects light from the light source 102 according to the wavelength of light. The SLO measurement light 106 reflected by the dichroic mirror 177 enters the dichroic mirror 173 through a common optical path with the OCT measurement light 104. Here, the common optical path of the SLO measurement light 106 and the OCT measurement light 104 includes a dichroic mirror 177, a beam splitter 171, mirrors 113 and 114, deformable mirror 182, mirrors 115 and 116, and a dichroic mirror 173.

  The dichroic mirrors 173 and 174 reflect the light from the light source 101 and transmit the light from the light source 102 according to the wavelength of the light. Therefore, the SLO measurement light 106 reflected by the mirror 116 passes through the dichroic mirror 173 and enters the X scanner 131 (third scanning means). The center of the SLO measuring beam 106 is adjusted to coincide with the rotation center of the X scanner 131. By rotating the X scanner 131, the SLO measuring beam 106 is used to move the retina Er in a direction perpendicular to the optical axis. Can be scanned. Although not shown, the X scanner 131 is connected to the control unit 190 and is controlled by the control unit 190. The X scanner 131 and the Y scanner 133 constitute SLO scanning means that scans the SLO measuring light 106 on the fundus of the eye E in a two-dimensional direction.

  In this embodiment, the optical path of the OCT measurement light 104 and the optical path of the SLO measurement light 106 are branched by the dichroic mirror 173, and the X scanner 132 of the OCT measurement light 104 and the X scanner 131 of the SLO measurement light 106 are separately arranged. . The scanning speed of the OCT measurement light 104 is limited by the reading speed of the line camera 191. On the other hand, the scanning speed of the SLO measuring light 106 can be increased by separately providing the X scanner 132 for the OCT measuring light 104 and the X scanner 131 for the SLO measuring light 106. As a result, the frame rate for acquiring the fundus front image using the SLO optical system can be increased. In the present embodiment, a resonance mirror is used as the X scanner 131, but an arbitrary deflection mirror may be used according to a desired configuration.

  The SLO measurement light 106 reflected by the X scanner 131 passes through the dichroic mirror 174 and enters the eye E again through a common optical path with the OCT measurement light 104. Here, the common optical path of the SLO measurement beam 106 and the OCT measurement beam 104 includes a dichroic mirror 174, mirrors 117 to 122, a Y scanner 133, a mirror 123, and dichroic mirrors 175 and 176. Here, to summarize the common optical path of the SLO measurement light 106 and the OCT measurement light 104, the common optical path includes the optical path of the dichroic mirror 177 to the dichroic mirror 173 and the optical path of the dichroic mirror 174 to the dichroic mirror 176.

  When entering the eye E, the SLO measurement light 106 is reflected or scattered by the retina Er, returns as the SLO return light 107, returns to the optical path of the SLO measurement light 106, is reflected by the dichroic mirror 177, and then passes through the beam splitter 172. . The SLO return light 107 transmitted through the beam splitter 172 is collected by the lens 156 and passes through the pinhole plate 178. The pinhole position of the pinhole plate 178 is adjusted to a position conjugate with the fundus oculi, and the pinhole plate 178 functions as a confocal stop that blocks unnecessary light from other than the conjugate point.

  The SLO return light 107 that has passed through the pinhole plate 178 is received by the light receiving element 192. In the present embodiment, an APD (Avalanche Photo Diode) is used as the light receiving element 192, but any other light receiving element may be used according to a desired configuration. The light receiving element 192 converts the received light into a voltage signal according to the light intensity. The obtained voltage signal group is converted into a digital value. The control unit 190 can perform data processing on the output signal of the light receiving element 192 converted into a digital value, and generate a fundus front image. In addition, the control unit 190 displays the generated fundus front image on the display unit 198. The data processing when generating the fundus front image may be any known data processing for generating the fundus front image from the output signal from the light receiving element 192.

  Next, the fixation lamp optical system will be described. The fixation lamp optical system includes a dichroic mirror 175 and a fixation lamp panel 194.

  The dichroic mirror 175 reflects the visible light of the fixation lamp panel 194 according to the wavelength of the light and transmits the light from the light source 101 and the light source 102. Thereby, the pattern displayed on the fixation lamp panel 194 is projected onto the retina Er of the eye E through the dichroic mirror 175. By displaying a desired pattern on the fixation lamp panel 194, the fixation direction of the eye E can be specified and the range of the retina Er to be photographed can be set. In this embodiment, an organic EL panel is used as the fixation lamp panel 194, but other displays may be used. The fixation lamp panel 194 is connected to the control unit 190 and is controlled by the control unit 190.

  Next, the anterior eye observation optical system will be described. The anterior eye observation optical system includes a dichroic mirror 176, an anterior eye observation camera 193, and an anterior eye illumination light source (not shown).

  The dichroic mirror 176 reflects the infrared light of the anterior eye illumination light source according to the wavelength of light, and transmits the visible light of the fixation lamp panel 194 and the light from the light source 101 and the light source 102. The optical axis of the anterior eye observation camera 193 is adjusted to coincide with the optical axes of the OCT optical system and the SLO optical system. For this reason, the image of the anterior eye part of the eye E to be examined based on the output from the anterior eye observation camera 193 is observed on the display unit and matched with the reference position, so that the X of the OCT optical system and the SLO optical system for the eye E to be examined The alignment in the direction and the Y direction can be performed. The anterior eye observation camera 193 is connected to the control unit 190 and is controlled by the control unit 190.

  Further, the focus of the anterior eye observation camera 193 is adjusted so that the iris of the eye E is in focus when it matches the working distance (working distance in the Z direction) of the OCT optical system and the SLO optical system. Therefore, the OCT optical system and the SLO optical system can be aligned in the Z direction by observing the iris in the anterior eye image on the display unit and focusing. In this embodiment, an LED having a wavelength of 970 nm is used as the anterior eye illumination light source, and a CCD camera is used as the anterior eye observation camera 193. However, the anterior eye illumination light source and the anterior eye observation camera are not limited to this, and other light sources, imaging elements, and the like can be used. Further, the wavelength of the anterior illumination light source is not limited to this, and may be changed according to a desired configuration.

(Relationship of shooting range)
Next, the relationship between the imaging ranges of the OCT optical system and the SLO optical system in this embodiment will be described with reference to FIG. In FIG. 2, the solid line indicates the imaging range 220 of the OCT optical system, and the inside of the broken line indicates the imaging range 210 of the SLO optical system, and the imaging range 220 and SLO of the OCT optical system when one line is captured with the OCT optical system. The relationship with the imaging | photography range 210 of an optical system is shown typically.

  In the OCT optical system and the SLO optical system, the Y scanner 133 is disposed in the common optical path, so that scanning is simultaneously performed in the Y direction (the vertical direction in the drawing of FIG. 2). On the other hand, since the X scanner 132 and the X scanner 131 are used as the X scanner, the photographing ranges in the X direction (left and right direction in FIG. 2) of the OCT optical system and the SLO optical system are set independently. Can be done. For example, in FIG. 2, the imaging range 220 of the OCT optical system is set approximately at the center of the imaging range 210 of the SLO optical system, but the relationship between the imaging ranges in the X direction is not limited to this. The imaging range 220 of the OCT optical system may be arbitrarily set regardless of the imaging range 210 of the SLO optical system.

  In addition, since the resonance mirror of the X scanner 131 has a higher scanning speed than the galvanometer mirror, the SLO measurement light 106 is scanned a plurality of times in the X direction during one Y-direction scan. Therefore, for example, an imaging range (one line) of an OCT optical system having a length L can be imaged by sampling (A scan) at m points, and an L × L SLO imaging range can be imaged by m X scans. . As a result, an L × L fundus front image (two-dimensional image) can be acquired by the SLO optical system while a one-line tomographic image having a length L is captured by the OCT optical system. In addition, the numerical values of L and m may be arbitrarily set according to a desired configuration.

  In addition, when shooting a 3D volume image, in addition to the scan of the Y scanner 133, the OCT measurement light 104 is scanned by the X scanner 132, and the scan position of the X scanner 132 is changed for the above-described shooting of one line in the Y direction. And repeat. For example, an L × L 3D volume image can be acquired by photographing m lines in the range of L in the X direction. During this period, m L × L fundus front images (two-dimensional images) can be acquired using the SLO optical system.

(Tracking procedure)
Next, a method of positional deviation correction (tracking) based on the fundus front image (two-dimensional image) acquired using the SLO optical system will be described.

  In the tracking process of the present embodiment, the control unit 190 uses the OLO optical system to capture the eye E to be examined acquired using the SLO optical system during the first imaging when imaging the line tomographic image at the same position a plurality of times. A fundus front image based on fundus information (first fundus information) is set as a reference image. Next, the control unit 190 uses the fundus front image based on the fundus information (second fundus information) acquired using the SLO optical system during the second and subsequent imaging using the OCT optical system as a target for detecting displacement. An image. The control unit 190 calculates the amount of positional deviation of the target image with respect to the reference image. The calculation of the amount of displacement can be performed by image processing such as pattern matching.

  The control unit 190 controls the X scanner 132 and the Y scanner 133 so as to correct the calculated displacement amount. As a result, the control unit 190 can perform fundus tracking that corrects a shift in the photographing position of the tomographic image based on the movement of the fundus due to fixation fine movement or the like. Note that a plurality of acquired line tomographic images at the same position can be used for noise reduction processing of the tomographic image by overlaying.

  This fundus tracking can be similarly applied when acquiring a 3D volume image using an OCT optical system. In this case, as described above, a one-line tomographic image in the Y direction is repeatedly acquired using the OCT optical system while changing the position in the X direction. At this time, the control unit 190 uses a fundus front image based on the fundus information of the eye E acquired at the first (first line) imaging as a reference image. Further, the control unit 190 sets the fundus front image based on the fundus information acquired at the time of the second and subsequent (second line) photographing as the target image. The control unit 190 calculates the amount of positional deviation between the reference image and the target image, and performs fundus tracking. Thereby, also when acquiring a 3D volume image, the shift | offset | difference of the imaging position of the tomographic image with respect to the retina Er of the eye E to be examined can be corrected.

  Note that, as the reference image, the entire area of the fundus front image acquired using the SLO optical system at the time of the first imaging using the OCT optical system may be used, or a partial image of the fundus front image may be used. Similarly, for the target image, the entire area of the fundus front image acquired using the SLO optical system may be used, or a partial image of the fundus front image may be used. When a partial image of the fundus front image is used as the target image, the acquisition interval of the target image can be shortened and the fundus tracking control rate can be increased. This makes it easier to correct misalignment due to faster movement of the fundus.

  Here, the image size of the reference image may be set larger than the image size of the target image. In this case, while maintaining the control rate while keeping the image size of the target image small, it is easy to ensure a large overlap area between the reference image and the target image even if the positional deviation amount between the reference image and the target image is large. It becomes easy to correct the deviation. When the fundus movement is slow and the fundus tracking control rate is sufficient, the image size of the target image may be set larger than the image size of the reference image. Even in this case, it becomes easy to correct a positional shift due to a large movement of the fundus. In other words, by setting one image size of the reference image and the target image to be larger than the other image size, it becomes easy to correct a positional shift due to a large movement of the fundus.

(Fundus procedure)
Next, with reference to FIGS. 3 and 4, a fundus photographing procedure in the fundus photographing apparatus 100 will be described. FIG. 3 is a flowchart of a fundus photographing procedure according to the present embodiment, and FIG. 4 is a screen of control software displayed on the display unit 198.

  First, in step S301, when the examiner presses the anterior eye illumination light source button 411, the control unit 190 turns on an anterior eye illumination light source (not shown). When the anterior eye illumination light source is turned on, the control unit 190 generates an anterior eye image of the eye E based on the output of the anterior eye observation camera 193, and the anterior eye image of the control software screen displayed on the display unit 198. It is displayed on the display unit 401.

  In step S <b> 302, the control unit 190 performs X, Y, and X on the eye E with respect to the imaging unit provided with the OCT optical system and the SLO optical system based on the anterior segment image displayed on the display unit 401. Alignment in the Z direction (anterior eye XYZ alignment) is performed. Specifically, the examiner observes the image of the anterior segment, and the control unit 190 controls a driving mechanism (not shown) of the imaging unit according to the input of the examiner, so that the imaging unit Align. As described above, the position of the anterior eye observation camera 193 in the X, Y, and Z directions is adjusted with respect to the OCT optical system and the SLO optical system. Therefore, the examiner adjusts the position of the imaging unit in the X, Y, and Z directions so that the XY position and the focus (Z position) of the image of the anterior segment displayed on the display unit 401 are aligned, thereby obtaining the OCT. The alignment of the optical system and the SLO optical system in the X, Y, and Z directions can be performed. The positioning of the imaging unit may be performed by an examiner operating a driving mechanism of the imaging unit (not shown).

  When the anterior eye XYZ alignment is completed, in step S303, the control unit 190 turns off the anterior eye illumination light source in response to the examiner pressing the anterior eye illumination light source button 411 again.

  When the anterior eye illumination light source is turned off, in step S304, the control unit 190 turns on the light source 101 of the OCT optical system and the light source 102 of the SLO optical system in response to the examiner pressing the light source button 412 on the control software screen. Note that the timing of turning on the light source 101 of the OCT optical system is not limited to this. For example, the light source 101 may be turned on after rough focus adjustment in step S306 described later.

  When the light source 102 of the SLO optical system is turned on, in step 305, the position of the fixation target displayed on the fixation lamp panel 194 is set according to the fixation target position setting performed by the examiner, and the range of the retina Er to be photographed. Set. Specifically, the examiner designates a desired position using the input unit 199 with respect to the grid of the fixation lamp position adjustment unit 402 on the control software screen, thereby fixing the fixation lamp panel 194 corresponding to the designated position. Turn on the cross fixation target in the area of.

  Next, the control unit 190 generates a fundus front image based on the output of the light receiving element 192 and displays it on the fundus display unit 405 of the control software screen. In step S <b> 306, the control unit 190 performs general focus adjustment (rough focus adjustment) of the SLO optical system and the OCT optical system in accordance with the examiner's input based on the fundus front image displayed on 405.

  Specifically, the control unit 190 moves the electric stage 126 according to the examiner observing the fundus front image of the display unit 405 and moving the focus adjustment bar 416 of the focus adjustment input unit 415 of the control software screen. . The motorized stage 126 and the mirrors 119 and 120 are disposed in a common optical path for the OCT measurement light 104 and the SLO measurement light 106. By adjusting the focus of the SLO measurement light 106, the OCT measurement light 104 is also simultaneously adjusted for rough focus. Is done. Here, focus adjustment is performed so that the luminance of the fundus front image is maximized.

  At this time, the control unit 190 places the electric stage 127 provided in the SLO optical system at a preset initial position. Here, as the position of the electric stage 127 in the initial state, the position of the electric stage 127 is set such that the focus positions of the OCT measurement light 104 and the SLO measurement light 106 substantially coincide.

  After performing the rough focus adjustment, in step S307, the control unit 190 determines the eye to be examined according to the input of the examiner based on the position of the Hartmann image displayed on the display unit 403 of the wavefront sensor 181 displayed on the control software screen. XY fine alignment of the photographing unit with respect to E is performed. In the XY fine alignment, the examiner observes the position of the Hartmann image on the display unit 403, and the control unit 190 performs fine alignment in the X and Y directions of the imaging unit with respect to the eye E according to the examiner's input. Do.

  Here, the wavefront sensor 181 is adjusted so that the center position of the wavefront sensor 181 matches the optical axes of the OCT optical system and the SLO optical system. Therefore, the examiner adjusts the position of the imaging unit with respect to the eye E so that the Hartmann image is aligned with the center of the wavefront sensor 181, thereby aligning the OCT optical system and the SLO optical system in the X direction and the Y direction. It can be performed. The display unit 403 may display an index or the like corresponding to the center position of the wavefront sensor 181 and a Hartmann image.

  After performing the XY fine alignment, in step S308, the control unit 190 starts wavefront correction by the deformable mirror 182 in response to the examiner pressing the wavefront correction button 412 on the control software screen. Here, the control unit 190 deforms the shape of the deformable mirror 182 based on the aberration measured by the wavefront sensor 181 to correct the aberration of the eye E other than the defocus component. Here, the aberration correction method using the deformable mirror may be performed by an existing method, and thus the description thereof is omitted.

  The deformable mirror 182 is disposed in a common optical path for the OCT measurement light 104 and the SLO measurement light 106. For this reason, the aberration of the eye E can be corrected also for the SLO measurement light 106 by correcting the aberration of the eye E by changing the shape of the deformable mirror 182 for the OCT measurement light 104.

  When the wavefront correction is started, the control unit 190 adjusts the optical path length of the reference light 103 in step S309. Specifically, when the examiner moves the reference optical path length adjustment bar 414 of the reference optical path length adjustment unit 413 on the control software screen, the control unit 190 controls the electric stage 125 to change the optical path length of the reference light 103. adjust. Here, the control unit 190 displays the tomographic image acquired using the OCT optical system on the tomographic image display unit 404 of the control software screen, and an image of a desired layer in the tomographic image is displayed according to the input by the examiner. The optical path length of the reference light 103 is adjusted so as to match a desired position in the tomographic image display area.

  When the optical path length of the reference light 103 is adjusted, in step S310, the control unit 190 performs focus adjustment of the SLO optical system and the OCT optical system. Specifically, when the examiner moves the focus adjustment bar 416 based on the fundus front image and the tomographic image, the control unit 190 controls the electric stage 126 to finely adjust the focus of the SLO optical system and the OCT optical system. I do. In the optical system of the compensation optical SLO with high lateral resolution, since the NA of the measurement light at the fundus is large and the depth of focus is shallow, only the region near the in-focus position in the depth direction of the retina Er is imaged. In step S310, focus adjustment is performed so that an image of the depth position of the retina Er intended by the examiner is acquired particularly for the fundus front image. For example, when a nerve fiber layer on the surface layer of the retina is to be imaged, the control unit 190 controls the electric stage 126 to adjust the focus so that the nerve fiber is depicted in the fundus front image.

  When the focus of the fundus front image is adjusted, in step S311, the control unit 190 performs fundus tracking in response to the examiner pressing the photographing button 418 on the control software screen, and simultaneously performs the fundus tomographic image and the fundus front image. Get the. Specifically, as described above, the control unit 190 that functions as an eye movement detection unit calculates a positional shift amount from the feature points of the fundus front image acquired using the SLO optical system, and based on the calculated shift amount. The fundus tracking is performed by controlling the X scanner 132 and the Y scanner 133. At the same time, interference light (light 108) between the OCT measurement light 104 and the reference light 103 is received by the line camera 191 and converted into a voltage signal. Further, the obtained voltage signal group is converted into a digital value, and data is stored and processed in the control unit 190. The control unit 190 generates a fundus tomographic image by processing data based on the interference light. Further, the SLO return light 107 is received by the light receiving element 192 and converted into a voltage signal. Further, the obtained voltage signal group is converted into a digital value, and data is stored and processed in the control unit 190. The control unit 190 processes the data based on the SLO return light 107 to generate a fundus front image. By simultaneously executing fundus tracking and image acquisition, the fundus imaging apparatus 100 can acquire a plurality of images used for noise processing by image superposition, a moving image, a 3D volume of a tomographic image, and the like with a small positional shift. When the acquisition of the predetermined number of planar images and tomographic images is completed, the control unit 190 ends the fundus tracking. Note that the shooting at step 311 is mainly for the purpose of acquiring the fundus front image. Since the tomographic images acquired at the same time have the focus positions of the OCT measurement light 104 and the SLO measurement light 106 substantially coincident with each other, the tomographic image in which the layer corresponding to the depth position of the retina Er reflected in the fundus front image is in focus Become.

  When the tracking end processing is completed, the process returns to step 310, and when the examiner wants to acquire the fundus front image again by changing the depth position, the focus adjustment of the SLO optical system and the OCT optical system in step S310 and the imaging in step S311 are performed. Repeatedly executed.

  Here, the relationship between step S312 and step S310 is annotated. S312 and S310 are exactly the same as the processing of the fundus imaging apparatus 100. However, since the focus adjustment state intended by the examiner is different, the step numbers are described separately. Therefore, the arrow that returns from step S311 to step S310 and the arrow that advances to step S312 represent the same state transition, and the transition occurs when the tracking end processing is completed in S311. As described above, step S310 is intended to match the fundus front image to the depth position intended by the examiner, whereas step S312 is suitable for tracking the fundus front image as described below. The purpose is to adjust the position.

  In step S312, focus adjustment is performed so that the fundus front image acquired using the SLO optical system becomes an image suitable for fundus tracking. Specifically, the control unit 190 controls the electric stage 126 in response to the examiner moving the focus adjustment bar 416. Here, focus adjustment is performed so that the contrast of photoreceptor cells in the fundus front image displayed on the display unit is increased. Note that the position where the SLO optical system is focused is not limited to the photoreceptor cell. The focus position of the SLO optical system may be a position having another feature point such as a blood vessel as long as a fundus front image having a characteristic for achieving a desired tracking accuracy can be acquired.

  When the focus is adjusted so that the contrast of photoreceptor cells in the fundus front image is increased, the control unit 190 switches the focus adjustment mode in step S313. Specifically, the mode is switched when the examiner presses a mode switching button 417 on the control software screen which is a means for selecting the mode. This is the first mode in which the focus of both the SLO optical system and the OCT optical system is adjusted by moving the focus adjustment bar 416 before pressing, whereas only the OCT optical system is adjusted after pressing. It becomes a mode. The control unit 190, which is also a display control unit, switches the mode switching button 417 to a display indicated by 450 in FIG. 5 when pressed, and notifies the examiner of the current mode with the button color and text.

  Here, the details of each mode will be described. In the first mode, in accordance with the operation of the focus adjustment bar 416, the control unit 190 controls the electric stage 126, which is the first focusing means provided on the common optical path, and focuses on both the SLO optical system and the OCT optical system. Adjust. This first mode is a mode in which the first focus adjusting means for adjusting the OCT focus and the second focus adjusting means for adjusting the SLO focus are interlocked. In the second mode, in accordance with the operation of the focus adjustment bar 416, the control unit 190 controls the electric stage 126 that is the first focusing means provided on the common optical path. At the same time, the motorized stage 127, which is the second focusing means arranged in the dedicated optical path of the SLO optical system branched from the common optical path, is also controlled. At this time, by controlling the electric stage 127 in a direction to cancel the adjustment by the electric stage 126, it is possible to adjust only the focus of the OCT optical system without changing the focus state of the SLO optical system. This second mode is a mode for controlling only the first focus adjusting means for adjusting the focus of the OCT.

  In this embodiment, the switching button 417, which is a mode setting unit displayed on the display unit 198, also serves as a mode notification unit depending on a change in color and text, but the configuration is not limited thereto. For example, as shown in FIG. 6, when a button 417 is pressed, a frame 451 surrounding the fundus front image display unit 405 may be displayed. In addition to changes in the background color and design of the control software, changes in the focus adjustment input unit 415, etc., a display unit 198 such as lamps attached to the device 100, voice functions, changes in the behavior of the device 100 that can be recognized by the examiner, etc. It is realizable with the other arbitrary alerting | reporting means not restricted to the display to. Similarly, the mode switching button 417 may be a soft switch such as a toggle switch or a check box, or any switching means such as a hardware switch or button, lever, touch pad, or voice recognition mounted on the apparatus 100 can be applied. Is possible.

  In the second mode in which only the OCT focus is adjusted, the focus adjustment of the OCT optical system is performed in step S314. Specifically, in response to the examiner moving the focus adjustment bar 416 based on the tomographic image, the control unit 190 controls the electric stages 126 and 127 to perform focus adjustment only for the OCT optical system. Also in the compensation optical OCT, the range of focus in the depth direction of the retina Er is limited due to the shallow depth of focus. Therefore, in step S314, focus adjustment is performed so that the OCT measurement light 104 is focused on the layer of the retina Er that is particularly desired to be photographed. For example, when a blood vessel on the surface layer of the retina is to be imaged, the control unit 190 controls the electric stages 126 and 127 to adjust the focus of the OCT measurement light 104 so that the luminance of that portion is maximized while checking the tomographic image. . Since step S314 is the second mode, the electric stage 127 is controlled to cancel the adjustment of the electric stage 126, and the focus of the SLO optical system does not change from the position adjusted in step S312.

  When the focus adjustment of the OCT optical system is completed and the examiner presses the photographing button 418 on the control software screen, the process proceeds to step S315, and the control unit 190 simultaneously acquires fundus tomographic images and fundus front images while performing fundus tracking. Do. The processing here is the same as in step S311, but the tomographic image is acquired at a focus position different from the front image while the fundus front image remains focused at the depth position of the retina Er suitable for fundus tracking in step S312. it can. That is, while performing accurate fundus tracking using the fundus front image acquired using the adaptive optics SLO optical system, the adaptive optics OCT optical system is used to focus on the desired layer of the retina Er. A fundus tomographic image having a good SN ratio and high resolution can be taken. When the acquisition of the predetermined number of planar images and tomographic images is completed, the control unit 190 ends the fundus tracking and returns to step S314.

  Here, when the examiner wants to change the focus to another layer of the retina Er and acquire a tomographic image again, the focus adjustment of the OCT optical system in step S314 and the imaging in step S315 are repeated.

Next, in any of the following cases, when the examiner presses the mode switch button 450 on the control software screen, the process proceeds to step S316, and the focus adjustment mode is switched.
Case 1: When photographing is repeated by repeating steps S314 and S315, the fundus front image deviates from the depth position suitable for fundus tracking adjusted in step S312 or the contrast decreases depending on the state of the subject's eye or the subject. Case 2: As steps S314 and S315 are repeated and imaging proceeds, it becomes difficult to determine the contrast of the tomographic image and the focus position depending on the condition of the subject's eye and the subject. Case 3: Case where the shooting position on the fundus is changed and the focus of the fundus front image is readjusted accordingly

  In step S316, when the examiner presses the mode switching button 450 on the control software screen, switching to the first mode in which the focus of both the SLO optical system and the OCT optical system is adjusted is executed. Further, when pressed, the mode switching button returns from the display of 450 to the display of 417 to notify the examiner that the mode 1 is set. In step S316, the control unit 190 controls the electric stage 127 to return to the initial position of the electric step 127 so that the focus positions of the OCT optical system and the SLO optical system substantially coincide. As a result, in the cases 1, 2, and 3, when the focus adjustment is performed again after returning to steps S312, S310, and S305, respectively, the focus positions of the SLO optical system and the OCT optical system are the same as when the above were performed. Focus adjustment can be performed in a substantially matched state. In this embodiment, the focus position of the SLO optical system is changed so as to substantially match the focus position of the OCT optical system set in step S314 by returning only the stage 127 to the initial state. However, the focus position of the SLO optical system may be changed so as to be substantially equal to the focus position of the SLO optical system set in step S312 by adjusting the position of the stage 126 simultaneously with the return of the stage 127 to the initial state. In addition, the initial state of the stage 127 may be variable by setting, or a plurality of focus feedback methods may be prepared including a setting that does not perform feedback.

  In the present embodiment, the mode for fixing the focus of the SLO measurement light has been described. However, a focus mechanism may be provided on the optical path side of the OCT optical system to fix the focus of the OCT measurement light. Thereby, a plurality of fundus front images at different focus positions can be acquired by the SLO optical system.

  As described above, in this embodiment, in an SLO / OCT composite apparatus having adaptive optics, shooting is performed while switching between a mode in which both SLO and OCT focus are linked and a mode in which the OCT focus and SLO focus are not linked. At this time, the current mode, that is, the focus adjustment target image is easily understood by the examiner.

[Second Embodiment]
A fundus photographing apparatus 700 according to the second embodiment of the present invention will be described with reference to FIGS. In this embodiment, in a fundus imaging apparatus provided with focusing means on the dedicated optical paths of OCT and SLO, the mode in which the focus of OCT and SLO are linked and the mode of adjusting the focus of OCT are notified by display on the focus adjustment unit. This is an example of making the current mode easy to understand for the examiner. It differs from the first embodiment in the configuration of the focusing means and the display contents for mode notification.

(Device configuration)
Hereinafter, with reference to FIG. 7, the fundus imaging apparatus 700 according to the present embodiment will be described focusing on differences from the fundus imaging apparatus 100 according to the first embodiment. FIG. 7 shows a schematic configuration of a fundus imaging apparatus 700 according to the present embodiment. In addition, about the structure similar to the fundus imaging apparatus 100 by 1st Embodiment, description is abbreviate | omitted using the same referential mark.

  The basic configuration of the fundus imaging apparatus 700 is the same as that of the fundus imaging apparatus 100 according to the first embodiment. However, the fundus imaging apparatus 700 is different from the fundus imaging apparatus 100 in that the focus unit is not disposed in the common optical path of the OCT optical system and the SLO optical system, and the first focus unit is disposed in the dedicated optical path of the OCT optical system. . In the fundus imaging apparatus 700, a focus lens 757 is disposed as a first focusing unit on a dedicated optical path of the OCT optical system branched from a common optical path of the OCT optical system and the SLO optical system. Accordingly, the electric stage 127 has been expanded so that the movement range corresponds to −12D to + 7D so that the diopter adjustment range of the SLO optical system can be secured.

  In the present embodiment, a focus lens 757 and a lens 758 are provided between the lens 154 and the dichroic mirror 177 in the optical path of the OCT measurement light 104. The focus lens 757 is mounted on the electric stage 727. The electric stage 727 can be moved in the optical axis direction of the OCT measurement light 104 as shown by an arrow under the control of the control unit 190.

  In FIG. 7, the focus lens 757 is shown as a convex lens, and the lens 758 is shown as a concave lens, but the configuration of the focus lens 757 and the lens 758 is not limited to this. The focus lens 757 may be a concave lens, the lens 758 may be a convex lens, or both may be convex lenses, and an intermediate image may be formed between them.

(Fundus procedure)
Next, with reference to FIG. 8 and FIG. 9, a fundus photographing procedure in the fundus photographing apparatus 700 of the present embodiment will be described. FIG. 8 is a flowchart of a fundus imaging procedure according to the present embodiment, and FIG. 9 is a screen of control software displayed on the display unit 198. Here, the same reference numerals are used for the same steps and configurations as in the first embodiment, and the description thereof is omitted.

  Shooting is started, and in steps S301 to S305, alignment and fixation lamp position adjustment are performed, the control unit 190 generates a fundus front image based on the output of the light receiving element 192, and the fundus display unit 405 of the control software screen. If displayed, the process proceeds to step S806.

  In step S806, the control unit 190 performs general focus adjustment (rough focus adjustment) of the SLO optical system and the OCT optical system in accordance with the examiner's input based on the fundus front image displayed on the display unit 405. Specifically, in response to the examiner observing the fundus front image of the display unit 405 and moving the focus adjustment bar 916 of the focus adjustment input unit 915 of the control software screen, the control unit 190 controls the electric stage 126 and the electric stage. 727 is moved. Here, the control unit 190 performs interlocking driving that drives both of the focus adjustment amounts of the SLO optical system driven by the electric stage 126 and the focus adjustment amounts of the OCT optical system driven by the electric stage 727. Thus, by performing focus adjustment of the SLO measurement light 106, the OCT measurement light 104 is also subjected to rough focus adjustment at the same time. Here, focus adjustment is performed so that the luminance of the fundus front image is maximized.

  At this time, the control unit 190 places the relative positions of the two electric stages 127 and 727 in a preset initial positional relationship. Here, as the positional relationship in the initial state, the positional relationship between the two stages is set such that the focus positions of the OCT measurement light 104 and the SLO measurement light 106 substantially coincide.

  When the rough focus adjustment is performed, the adjustment of the optical path length of the reference light 103 is completed from the XY fine alignment based on the position of the Hartmann image 403 in steps S307 to S309.

  When the reference optical path length adjustment is completed, in step S810, the control unit 190 performs focus adjustment of the SLO optical system and the OCT optical system. Specifically, the examiner moves the focus adjustment bar 916 based on the fundus front image and the tomographic image. In response to this, the control unit 190 controls the electric stages 127 and 727 in the same manner as in step S806 to perform fine focus adjustment of the SLO optical system and the OCT optical system. Focus adjustment is performed so that the fundus front image at the depth position of the retina Er intended by the examiner is acquired.

  When the focus of the fundus front image is adjusted, in step S311, the control unit 190 performs fundus tracking in response to the examiner pressing the photographing button 418 on the control software screen, and simultaneously performs the fundus tomographic image and the fundus front image. Get the. When the acquisition of the predetermined number of images is completed, the control unit 190 ends the fundus tracking and returns to step S810.

  When the examiner wants to acquire the fundus front image again by changing the depth position, the focus adjustment of the SLO optical system and the OCT optical system in step S310 and the imaging in step S311 are repeatedly executed according to the operation of the examiner. .

  Here, as in the first embodiment, steps S810 and S812 are the same processing, and only the purpose of adjusting the fundus front image to a depth position intended by the examiner or a position suitable for tracking is different. It is. When all the acquisition of the fundus front image of the intended depth is completed, the process of step S812 is executed by the examiner's operation.

  In step S812, the control unit 190 performs focus adjustment so that the fundus front image acquired using the SLO optical system becomes an image suitable for fundus tracking. Specifically, in response to the examiner moving the focus adjustment bar 916, the control unit 190 controls the electric stages 127 and 727 in conjunction with step S806. In order to achieve the required tracking accuracy, focus adjustment is performed so that a fundus front image with high contrast of photoreceptor cells is obtained.

  When the focus is adjusted so that the contrast of the photoreceptor cells in the fundus front image is increased, the control unit 190 switches the focus adjustment mode in step S813. Specifically, the mode is switched when the examiner presses the mode switching button 419 on the control software screen. This is the first mode in which the focus of both the SLO optical system and the OCT optical system is adjusted in conjunction with each other by moving the focus adjustment bar 916 before pressing, whereas the focus of the OCT optical system is adjusted after pressing. Is the second mode. The control unit 190, which is also a display control unit, switches the focus adjustment input unit to the display indicated by 917 in FIG. 10 when pressed, and notifies which focus adjustment is in effect by changing the form of the focus adjustment bars 916 to 918. To do. In the second mode, only the focus of the OCT optical system is adjusted when the control unit 190 drives only the electric stage 727 by operating the focus adjustment bar 918.

  In this embodiment, the focus adjustment input unit 915 displayed on the display unit 198 also serves as a mode notification unit depending on the change in the form, but the configuration is not limited thereto. As shown in FIG. 11, a notification state in which the effective range of the focus adjustment input unit is clearly indicated by a frame 461, or a notification state in which the other focus adjustment bar as shown in FIG. The notification mode for clearly indicating whether the focus adjustment input unit is effective for OCT or SLO at the display position of the focus adjustment input unit as shown in FIG. 13, and the mode is specified by the color of the frame of the image display unit as shown in FIG. Any notification state, such as a notification state such as, can be applied.

  In the second mode in which only the OCT optical system is adjusted, the process proceeds to the next step S814, and the focus adjustment of the OCT optical system is performed. Specifically, in response to the examiner moving the focus adjustment bar 918 based on the tomographic image, the control unit 190 controls the electric stage 127 to perform focus adjustment only for the OCT optical system. Focus adjustment is performed so that the OCT measurement light 104 is focused on the layer of the retina Er to be photographed.

  When the focus adjustment of the OCT optical system is completed and the examiner presses the photographing button 418 on the control software screen, the process proceeds to step S315, and the control unit 190 simultaneously acquires fundus tomographic images and fundus front images while performing fundus tracking. Do. When the acquisition of the predetermined number of planar images and tomographic images is completed, the control unit 190 ends fundus tracking and returns to step S814. Here, when the examiner wants to change the focus to another layer of the retina Er and acquire a tomographic image again, the focus adjustment of the OCT optical system in step S814 and the imaging in step S315 are repeated.

  Next, in any case described in the first embodiment, when the examiner presses the mode switch button 419 on the control software screen, the process proceeds to step S816, and the focus adjustment mode is switched. Specifically, the control unit 190 switches the focus adjustment mode to the first mode in which the focus of both the SLO optical system and the OCT optical system is adjusted. In addition, the focus adjustment input unit returns from the display 917 to the display 915 to notify the examiner that the mode 1 is set. Further, the control unit 190 controls the electric stage 727 so that the focus position of the OCT optical system substantially coincides with the focus position of the SLO optical system, thereby setting the relative position of the two electric stages 127 and 727 to the initial position. Return to relationship.

  With the notification function as described above, in this embodiment, in the SLO and OCT combined apparatus having adaptive optics, shooting is performed while switching between a mode in which both SLO and OCT focus are linked and a mode in which only the OCT focus can be operated. In this case, the current mode becomes easier for the examiner to understand.

[Modification 1]
In the first embodiment, the mirrors 119 and 120 mounted on the electric stage 126 disposed in the common optical path of the OCT optical system and the SLO optical system are used as the first focusing means, and these are moved to perform rough focus adjustment and Fine focus adjustment was performed. However, the first focusing means used for these focus adjustments is not limited to this. For example, a deformable mirror 182 disposed in the common optical path of the OCT optical system and the SLO optical system can be used as the first focusing unit.

  In particular, fine focus adjustment may be performed by deforming the deformable mirror 182. In this case, the control unit 190 controls the target shape of the deformable mirror 182 based on the measurement value of the wavefront sensor 181 by giving a defocus component offset. Thereby, it is possible to change the focus positions of the OCT optical system and the SLO optical system while correcting the aberration of the eye E. In the rough focus adjustment, the deformable mirror 182 can be used in the same manner if the focus adjustment amount is small.

  Further, as the first focusing means, any other focusing means such as a focus lens, an electro-optical element, a piezo element, a liquid crystal optical element, a deformable mirror, or the like may be used.

  In the embodiment and the modification described above, the control unit 190 performs various types of alignment, optical path length adjustment, and focus adjustment according to the input of the examiner. However, based on the above-described various alignments, the optical path length adjustment, the image of the anterior segment used in the focus adjustment, the fundus front image, the Hartmann image, the tomographic image, and the like, the control unit 190 automatically performs these alignments. Adjustments may be made. In this case, for example, the control unit 190 can perform these alignments and adjustments based on the luminance of the fundus front image, the layer to be photographed, and the like, in the same manner as the alignment and adjustment described above.

  In the above-described embodiments and modifications, the spectral domain OCT (SD-OCT) optical system using an SLD as a light source has been described as the OCT optical system. However, the configuration of the OCT optical system according to the present invention is not limited thereto. . For example, the present invention can be applied to any other type of OCT optical system such as a wavelength sweep type OCT (SS-OCT) optical system using a wavelength swept light source capable of sweeping the wavelength of emitted light. .

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

  Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. Inventions modified within the scope not departing from the spirit of the present invention and inventions equivalent to the present invention are also included in the present invention. Moreover, each above-mentioned embodiment and modification can be combined suitably in the range which is not contrary to the meaning of this invention. In addition, not all combinations of features described in the embodiments and the modifications are essential for the solution means of the present invention.

Claims (12)

An OCT optical system for acquiring tomographic information of the eye to be examined using OCT measurement light;
An SLO optical system for acquiring fundus information of the eye to be examined using SLO measurement light;
First focus adjustment means for adjusting the focus of the OCT measurement light;
Second focus adjustment means for adjusting the focus of the SLO measurement light;
Control means for controlling the first focus adjustment means and the second focus adjustment means;
The first mode for controlling the first focus adjustment unit and the second focus adjustment unit in conjunction with each other, and one of the first focus adjustment unit and the second focus adjustment unit are controlled. Selecting means for selecting any mode from the second mode;
An ocular fundus imaging apparatus comprising an informing means for informing the selection state. First focusing means provided on a common optical path of the OCT optical system and the SLO optical system;
A second focusing means provided on the optical path of the SLO optical system and not included in the OCT optical system;
The first focus adjustment means adjusts the focus of the OCT measurement light by adjusting the first focus means, and the second focus adjustment means adjusts the first focus means and the second focus means. The fundus imaging apparatus according to claim 1, wherein the focus of the SLO measurement light is adjusted. An aberration measuring means for measuring the aberration of the OCT measurement light;
An aberration correction unit that is provided on the common optical path and corrects the aberration;
Further comprising
The fundus imaging apparatus according to claim 1, wherein the control unit controls the aberration correction unit based on the aberration measured by the aberration measurement unit.   The fundus imaging apparatus according to claim 3, wherein the aberration correction unit is used as at least part of the first focusing unit. It further has display control means for displaying the mode setting section on the display means,
The fundus imaging apparatus according to any one of claims 1 to 4, wherein the selection unit selects one of the modes by setting the mode setting unit. Further comprising information display control means for displaying the tomographic information of the eye to be examined and the fundus information of the eye to be examined on a display means,
The fundus imaging apparatus according to claim 1, wherein the notification unit changes information displayed on the information display control unit according to the selection state. A means for displaying the focus adjustment input section on the display means;
The fundus imaging apparatus according to claim 1, wherein the notification unit changes the display of the focus adjustment input unit in accordance with the selection state. Scanning means for scanning the SLO measurement light in a two-dimensional direction on the fundus of the eye to be examined;
The control means includes
Detecting the movement of the fundus based on the fundus information of the eye to be examined;
The fundus imaging apparatus according to claim 1, wherein the scanning unit is controlled based on the detected movement of the fundus.   The control means adjusts the focus of the OCT measurement light and the focus of the SLO measurement light to a predetermined positional relationship when switching the mode from the second mode to the first mode. The fundus imaging apparatus according to any one of claims 1 to 8.   10. The predetermined positional relationship is a position where one of the focus of the OCT measurement light and the focus of the SLO measurement light coincides with the other focus. Fundus photographing device. An OCT optical system that obtains tomographic information of the eye to be examined using OCT measurement light, an SLO optical system that obtains fundus information of the eye to be examined using SLO measurement light, and a first that adjusts the focus of the OCT measurement light. Fundus imaging apparatus comprising: a focus adjustment unit; a second focus adjustment unit that adjusts the focus of the SLO measurement light; and a control unit that controls the first focus adjustment unit and the second focus adjustment unit. Control method,
The first mode for controlling the first focus adjustment unit and the second focus adjustment unit in conjunction with each other, and one of the first focus adjustment unit and the second focus adjustment unit are controlled. Selecting any mode from the second mode;
A method for controlling a fundus imaging apparatus, comprising: a notification step of notifying the selection state.   A program for realizing each means of the fundus imaging apparatus according to claim 1 by a computer.

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