JP2019103746A - Fundus imaging apparatus - Google Patents

Abstract

To provide a fundus imaging apparatus, regardless of a compact apparatus configuration, capable of locating focal positions of an OCT optical system and an SLO optical system on different positions.SOLUTION: The fundus imaging apparatus includes: an OCT optical system for acquiring tomographic information of a subject's eye using OCT measuring light; an SLO optical system for acquiring fundus information of the subject's eye using SLO measuring light; a common optical path in which the OCT optical system and the SLO optical system share at least a part of optical paths of the OCT measuring light and the SLO measuring light; first focus means provided at the common optical path; and second focus means branched from the common optical path and provided at least one of the optical path of the OCT measuring light and the optical path of the SLO measuring light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fundus imaging apparatus.

  In the field of ophthalmology, optical coherence tomography (OCT) using multi-wavelength light wave interference is known. In OCT, tomographic images of a sample (in particular, the fundus) can be obtained with high resolution. Hereinafter, an apparatus for capturing a tomographic image by such OCT will be referred to as an OCT apparatus.

  In addition, a scanning laser ophthalmoscope (SLO: Scanning Laser Ophthalmoscope), which is an ophthalmologic apparatus using the principle of a confocal laser microscope, is also known. In SLO, raster scanning is performed on the fundus using a laser as measurement light, and a planar image of the fundus can be obtained at high resolution and at high speed from the intensity of the return light. Hereinafter, an apparatus for capturing such a planar image will be referred to as an SLO apparatus.

  In recent years, as devices for imaging the fundus, devices that scan illumination light to image the fundus, such as an OCT device and an SLO device, are actively used. Further, by increasing the beam diameter of measurement light in these fundus imaging devices, it has become possible to acquire an image of the retina with an improved lateral resolution.

  However, as the beam diameter of the measurement light is increased, a decrease in the SN ratio and resolution of the image due to the aberration of the eye to be examined becomes a problem in acquisition of the fundus image. In order to solve this, an adaptive optics system that has an adaptive optics 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 by the subject's eye and its return light using a wavefront correction device. OCT devices and adaptive optics SLO devices have been developed. By using these devices, it is possible to compensate for the aberration of the eye to be examined 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 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 can be obtained is limited. Therefore, in order to obtain an image with a better SN ratio using the adaptive optical OCT apparatus, it is important to match the focus position of the OCT measurement light more precisely to the layer to be photographed of 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. Therefore, the subject is susceptible to involuntary eye movement called involuntary eye movement, eye movement due to poor fixation, or movement of the face, and fundus tracking for tracking the movement of the fundus becomes more important. In particular, in an apparatus for acquiring an image with high lateral resolution such as an adaptive optics OCT apparatus or an adaptive optics SLO apparatus, fundus tracking with higher accuracy is important.

  Patent Document 1 proposes an ophthalmologic apparatus having a configuration in which an adaptive optics OCT apparatus and an adaptive optics SLO apparatus are combined.

Unexamined-Japanese-Patent No. 2015-221091

  In Patent Document 1, a part of an optical system of an OCT apparatus and a part of an optical system of an SLO apparatus are used as a common optical path, and a diopter correction optical system using a reflective optical system in the common optical path is configured. As a result, the focal positions of the OCT apparatus and the SLO apparatus are aligned with the fundus, and a fundus tomographic image by the OCT apparatus and a fundus front image by the SLO apparatus are simultaneously acquired.

  However, since the diopter correction optical system is disposed in the common optical path of the OCT apparatus and the SLO apparatus, the amount of focal position of the OCT apparatus and the SLO apparatus are the same when the focal position is changed using this diopter correction optical system. Only changed. Therefore, when photographing a layer with few feature points such as photoreceptors (for example, the inner layer of the retina) with the OCT device, the SLO device also brings the focus position to the layer with few feature points at the same time as focusing the OCT device. .

  When performing fundus tracking using the fundus front image acquired by the SLO device, the amount of positional deviation is detected from feature points such as photoreceptors of the photographed fundus front image, and the fundus is detected based on the detected positional deviation. Track the movement of Therefore, when the focus position is aligned to a layer with few feature points, the detection accuracy of the positional deviation amount is lowered, and it is difficult to perform accurate fundus tracking.

  On the other hand, an apparatus configuration may be considered in which diopter correction optical systems of the OCT apparatus and the SLO apparatus are disposed not in the common optical path of the OCT optical system and the SLO optical system but in dedicated optical paths. However, in this case, since each diopter correction optical system needs to correspond to the diopter range of the subject eye to be photographed, the moving range of the diopter correction optical system becomes wide, and the apparatus tends to be large.

  Further, in a wavefront compensation apparatus using a wavefront sensor, it is advantageous to mainly construct an optical system with a reflection optical system in order to reduce unnecessary stray light to the wavefront sensor. However, when the diopter correction optical system disposed in the dedicated optical path of the OCT optical system and the SLO optical system is configured of the reflection optical system, the moving range of the diopter correction optical system at the time of diopter correction becomes wider. In this case, since the space corresponding to the movement range of the diopter correction optical system is further required, the apparatus is further enlarged.

  Therefore, the present invention provides a fundus imaging apparatus capable of adjusting focal positions of an OCT optical system and an SLO optical system to different positions while having a compact apparatus configuration.

  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 inspected using SLO measurement light A common optical path in which the OCT optical system and the SLO optical system share at least a part of the optical paths of the OCT measurement light and the SLO measurement light, a first focusing unit provided in the common optical path, and the common The optical path of the said SLO measurement light branched from the optical path and the 2nd focusing means provided in at least one of the optical path of the said OCT measurement light are provided.

  According to the present invention, the focal positions of the OCT optical system and the SLO optical system can be adjusted to different positions while having a compact device configuration.

1 shows a schematic configuration of a fundus imaging apparatus according to a first embodiment. The imaging range of the OCT optical system in a fundus imaging device and a SLO optical system is shown roughly. It is the flowchart which showed the photographing procedure of the fundus oculi concerning a 1st embodiment. The schematic structure of the fundus imaging device by 2nd Embodiment is shown. It is the flowchart which showed the photographing procedure of the fundus oculi concerning a 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, relative positions of components, and the like 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, like reference numerals are used to indicate identical or functionally similar elements.

  In addition, although the retina of a human eye is demonstrated as a to-be-tested object below, a to-be-tested object is not restricted to this, for example, it is good also considering an anterior eye part etc. of a human eye as a to-be-tested object.

First Embodiment
The fundus imaging apparatus according to the first embodiment of the present invention, which is used to acquire an image of the fundus of an eye to be examined, etc., will be described in detail below with reference to FIGS. 1 to 3.

(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 according to the present embodiment is provided with an OCT optical system, an SLO optical system, an anterior observation optical system, a fixation lamp optical system, and a control unit 190 (control means). In the present embodiment, the entire optical system is mainly configured by a reflection optical system using a mirror.

  Further, the control unit 190 may be configured using a general-purpose computer, or may be configured as a computer dedicated to the fundus imaging device 100. The control unit 190 may be configured separately from or integrally with the imaging unit including the OCT optical system, the SLO optical system, the anterior eye observation optical system, and the fixation lamp optical system. .

  First, the OCT optical system of the fundus imaging device 100 will be described. The light source 101 is a light source for generating light (low coherent light). In the present 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, any type of light source may be used as long as it 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 the light emitted from the light source 101 can be a wavelength corresponding to near infrared light in view of measuring the eye. Further, the wavelength of the light emitted from the light source 101 affects the resolution in the lateral direction of the obtained tomographic image, and thus can be as short as possible, and in the present embodiment, the central wavelength is 830 nm. In addition, you may select another wavelength depending on the measurement site | part of observation object. In addition, the wider the wavelength band, the better the resolution in the depth direction. Generally, when the central wavelength is 830 nm, the resolution of 6 μm in the 50 nm band and 3 μm in the 100 nm band. The center wavelength and the 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 is guided through a single mode fiber 142 to an optical coupler 141 which is a light dividing means. The light emitted from the light source 101 is divided by the optical coupler 141 at an intensity ratio of 90:10 to become the reference light 103 and the OCT measurement light 104, respectively. The division ratio is not limited to this, and can be appropriately selected in accordance with the object to be inspected.

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

  The dispersion compensating glass 159 can compensate the dispersion when the OCT measurement light 104 reciprocates between the eye E and the lens 154 with respect to the reference light 103.

  The mirror 124 is mounted on the motorized stage 125 and constitutes an optical path length adjusting means. The motorized stage 125 can move in the direction of the optical axis of the reference beam 103 as shown by the arrow, and the optical path length of the reference beam 103 can be adjusted by moving the position of the mirror 124. The motorized stage 125 is controlled by the controller 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 through 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 is incident on 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 which is an aberration measurement unit. Mirror device.

  In the present embodiment, the deformable mirror is used as the aberration correction means, but the aberration correction means may be any one as long as it can correct the aberration, and a spatial light phase modulator using liquid crystal or the like can also be used. Further, in the present embodiment, a Shack-Hartmann wavefront sensor 181 is used as an aberration measurement unit. However, the aberration measurement means is not limited to this, and may be configured using any known sensor or the like for measuring the 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 is incident on the X scanner 132 (second scanning unit). The center of the OCT measurement light 104 is adjusted to coincide with the rotation center of the X scanner 132, and the X scanner 132 is rotated to align the optical axis on the retina Er of the eye E using the OCT measurement light 104. It can scan in the vertical direction. Here, a galvano mirror is used as the X scanner 132. The X scanner 132 may be configured by any other deflecting 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 motorized stage 126, and constitute first focusing means. The motorized stage 126 can be moved towards or away from the mirrors 118, 121 as illustrated by the arrows. The motorized stage 126 is controlled by the controller 190. The mirrors 119 and 120 are disposed in a common optical path of the OCT optical system and the SLO optical system. Therefore, by moving the mirrors 119 and 120 by the motorized stage 126, the focus states of the OCT measurement light 104 and the SLO measurement light 106 can be adjusted according to the diopter of the eye E to be examined.

  In this embodiment, the movement range of the motorized 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 to be examined. . The movement range of the motorized stage 126 may be arbitrarily set according to a desired configuration.

  Here, in the present embodiment, the first focusing unit disposed in the common optical path of the OCT optical system and the SLO optical system is configured of a buddle optical system by the 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 aberration measurement and aberration correction can be performed with high accuracy.

  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 to coincide with the rotation center of the Y scanner 133, and by rotating the Y scanner 133, the OCT measurement light 104 is used to measure the optical axis of the retina Er and the X scanner 132. It can scan in the direction perpendicular to the scan direction. Here, a galvano mirror is used as the Y scanner 133. The Y scanner 133 may be configured by any other deflecting 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 OCT scanning means for scanning the OCT measurement light 104 in a two-dimensional direction on the fundus of the eye E.

  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. 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. The retina Er can be scanned with the vicinity of the pupil Ep as a fulcrum using the OCT measurement light 104 by the optical system.

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

  The reference light 103 and the OCT return light 105 are combined by the optical coupler 141 and become interference light. Here, when the optical path lengths of the OCT measurement light 104 and the OCT return light 105 become 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 adjusts the optical path length of the reference light 103 to the optical path lengths of the OCT measurement light 104 and the OCT return light 105 which change depending on the measurement target of the eye E by controlling the motorized stage 125 and moving the mirror 124 Can. The combined light 108 (interference light) is emitted as spatial light from the single mode fiber 144, and is guided to the transmission grating 161 through the lens 152. Thereafter, the light 108 is dispersed for each wavelength by the transmission grating 161, condensed by the lens 153, and is incident on the line camera 191.

  The light 108 incident on the line camera 191 is converted into a voltage signal (interference signal) according to the light intensity at each position (wavelength) on the line camera 191. Specifically, interference fringes in a spectral region on the wavelength axis are observed on the line camera 191. The obtained voltage signals are converted into digital values. The control unit 190 can generate a tomographic image of the eye E by subjecting the interference signal converted into the digital value to data processing. The control unit 190 also displays the generated tomographic image on a display unit (not shown). The display unit may be configured by any monitor, may be configured separately from the imaging unit or the control unit 190, or may be configured integrally. Also, data processing at the time of generating a tomographic image may be any known data processing for generating a tomographic image from an interference signal.

  The single mode fibers 142 and 143 are provided with polarization adjustment paddles 183 and 184, respectively. The polarization adjusting paddles 183 and 184 can adjust the polarization of light passing through the single mode fibers 142 and 143. By using the polarization adjusting 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 coincide. Can be The position at which the polarization adjusting paddle is provided is not limited to this, and may be provided in the single mode fiber 145 or the like.

  The OCT return light 105 is split by the beam splitter 171 when returning the optical path of the OCT measurement light 104, and a part of the OCT return light 105 is incident on 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 an 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 to grasp the aberration of the eye to be examined 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 motorized stage 126 with respect to the defocus component of the Zernike polynomial. The control unit 190 also controls the surface shape of the deformable mirror 182 to correct the components other than defocus. Thereby, the control unit 190 can generate (acquire) a high lateral resolution tomographic image.

  Here, the mirrors 113 to 123 are disposed such that the pupil Ep, the X scanner 132, the Y scanner 133, the wavefront sensor 181, and the deformable mirror 182 are optically conjugate. Thus, 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 of 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 also be used as the light source 102. Also, the wavelength of the light source 102 is not limited to this, and may be changed according to the 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 the intensity ratio of the transmitted light and the reflected light (SLO measurement light 106) is split at 90:10. The SLO measurement light 106 reflected by the beam splitter 172 passes through the focusing lens 157 and the lens 158.

  The focusing lens 157 is mounted on the motorized stage 127, and constitutes a second focusing means. The motorized stage 127 can move in the direction of the optical axis of the SLO measurement light 106 as shown by the arrow, and can adjust the focus state of the SLO measurement light 106. The motorized stage 127 is controlled by the controller 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 controlling the motorized stage 127 to move the focus lens 157. Here, the movement range of the motorized stage 127 is 10 mm, and the movement range corresponds to the diopter range of -2D to + 2D. The movement range of the motorized stage 127 is not limited to this, and may be set to any movement range narrower than the movement range of the motorized stage 126.

  In this embodiment, focus adjustment of the OCT measurement light 104 and the SLO measurement light 106 is performed using the first focusing unit to perform diopter correction of the eye E, so the focus adjustment range of the second focusing unit is narrowed. be able to. Therefore, the movement range of the motorized stage 127 can be narrower than the movement range of the motorized stage 126. Accordingly, since the focal positions of the OCT optical system and the SLO optical system can be adjusted to different positions by using a smaller stage, the optical system can be miniaturized.

  Although FIG. 1 illustrates the focus lens 157 as a convex lens and the lens 158 as a concave lens, the configuration of the focus lens 157 and the lens 158 is not limited to this. The focus lens 157 may be a concave lens and the lens 158 may be a convex lens, or both may be convex lenses to form an intermediate image therebetween.

  The light transmitted through the focusing lens 157 and the lens 158 is directed to the dichroic mirror 177. The dichroic mirror 177 transmits the light from the light source 101 and reflects the light from the light source 102 according to the wavelength of the light. The SLO measurement light 106 reflected by the dichroic mirror 177 passes through a common optical path with the OCT measurement light 104 and enters the dichroic mirror 173. Here, the common light 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, a 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 is incident on the X scanner 131 (third scanning unit). The center of the SLO measurement light 106 is adjusted to coincide with the rotation center of the X scanner 131, and by rotating the X scanner 131, using the SLO measurement light 106, the retina Er on the retina Er in a direction perpendicular to the optical axis. It 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 for scanning the SLO measurement light 106 in a two-dimensional direction on the fundus of the eye E to be examined.

  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 disposed. . 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 measurement light 106 can be increased by separately setting the X scanner 132 of the OCT measurement light 104 and the X scanner 131 of the SLO measurement light 106. Thereby, it is possible to increase the frame rate for acquisition of the fundus plane planar image using the SLO optical system. In the present embodiment, a resonant mirror is used as the X scanner 131, but any deflection mirror may be used according to the desired configuration.

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

  The SLO measurement light 106 is reflected or scattered by the retina Er when entering the eye E, returns as the SLO return light 107 back to the optical path of the SLO measurement light 106, is reflected by the dichroic mirror 177, and transmits 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 to the fundus, and the pinhole plate 178 acts as a confocal stop that blocks unnecessary light from points 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 depending on the desired configuration. The light receiving element 192 converts the received light into a voltage signal according to the light intensity. The obtained voltage signals are converted into digital values. The control unit 190 can perform data processing on the output signal of the light receiving element 192 converted into the digital value to generate a fundus planar image. In addition, the control unit 190 displays the generated fundus planar image on a display unit (not shown). The data processing at the time of generating the fundus planar image may be any known data processing for generating the fundus planar 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 is composed of a dichroic mirror 175 and a fixation lamp panel 194.

  The dichroic mirror 175 reflects visible light of the fixation lamp panel 194 and transmits light from the light sources 101 and 102 in accordance with the wavelength of the light. Thus, the pattern displayed on the fixation lamp panel 194 is projected onto the retina Er of the eye E via the dichroic mirror 175. By displaying a desired pattern on the fixation lamp panel 194, the fixation direction of the eye to be examined E can be designated, and the range of the retina Er to be imaged can be set. In the present embodiment, an organic EL panel is used as the fixation lamp panel 194, but another display 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 infrared light of the anterior illumination light source according to the wavelength of light, and transmits visible light of the fixation lamp panel 194 and 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. Therefore, by observing the image of the anterior segment of the subject's eye E based on the output from the anterior eye observation camera 193 on the display part and aligning it with the reference position, X of the OCT optical system and the SLO optical system for the subject's eye E Alignment in the direction and in 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 as to focus on the iris of the eye to be examined E when it matches the working distance (working distance in the Z direction) of the OCT optical system and the SLO optical system. Therefore, alignment in the Z direction of the OCT optical system and the SLO optical system can be performed by observing the iris in the image of the anterior segment on the display and focusing. In the present embodiment, an LED with 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 and imaging devices can also be used. Also, the wavelength of the anterior eye illumination light source is not limited to this, and may be changed according to the desired configuration.

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

  The OCT optical system and the SLO optical system are scanned at the same time in the Y direction (vertical direction in the drawing of FIG. 2) because the Y scanner 133 is disposed in the common optical path. On the other hand, since X scanner 132 and X scanner 131 separate scanners are used as X scanners, imaging 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. It 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 of the imaging range in the X direction is not limited thereto. The imaging range 220 of the OCT optical system may be arbitrarily set regardless of the imaging range 210 of the SLO optical system.

  Further, since the resonant mirror of the X scanner 131 has a scanning speed faster than that of the galvano mirror, the SLO measurement light 106 is scanned a plurality of times in the X direction during one scanning in the Y direction. Therefore, for example, the imaging range (1 line) of the OCT optical system of length L can be imaged by sampling (A scan) of m points, and the SLO imaging range of L × L can be imaged by m times of X scans . Thus, it is possible to acquire an L × L fundus front image (two-dimensional image) with the SLO optical system while capturing a tomographic image of one line of length L with the OCT optical system. The numerical values of L and m may be arbitrarily set according to the desired configuration.

  In addition to scanning with the Y scanner 133, when capturing a 3D volume image, the OCT measurement light 104 is scanned by the X scanner 132, and the scanning position of the X scanner 132 is changed for the above-described one line imaging 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. Further, during this period, it is possible to acquire m L × L fundus front images (two-dimensional images) 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 is configured to use the SLO optical system to acquire the first tomographic image when the line tomographic image at the same position is captured multiple times using the OCT optical system. A fundus front image based on fundus information (first fundus information) is used as a reference image. Next, the control unit 190 sets a fundus image as a target image for detecting misalignment based on fundus information (second fundus information) acquired using the SLO optical system at the second and subsequent photographing using the OCT optical system. I assume. The control unit 190 calculates the amount of positional deviation of the target image with respect to the reference image. The positional deviation amount can be calculated 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 positional deviation amount. Thereby, the control unit 190 can perform fundus tracking which corrects the shift of the imaging position of the tomographic image based on the movement of the fundus due to the involuntary eye movement or the like. The acquired line tomographic images of the same position can be used for noise reduction processing of tomographic images by superposition.

  The fundus tracking can be similarly applied to the case of acquiring a 3D volume image using an OCT optical system. In this case, as described above, a tomographic image of one line in the Y direction is repeatedly acquired while changing the position in the X direction using the OCT optical system. At this time, the control unit 190 sets a fundus oculi front image based on the fundus oculi information of the subject eye E acquired at the time of the first imaging (first line) as a reference image. Further, the control unit 190 sets a fundus oculi front image based on fundus information acquired at the time of imaging for the second (second line) and subsequent times as a 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, even when acquiring a 3D volume image, it is possible to correct the shift of the imaging position of the tomographic image with respect to the retina Er of the eye E to be examined.

  Note that the entire area of the fundus front image obtained using the SLO optical system may be used as the reference image at the first imaging using the OCT optical system, 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 a fundus front image is used as the target image, the acquisition interval of the target image can be shortened, and the control rate of the fundus tracking can be increased. This makes it easy to correct positional deviation due to faster movement of the fundus.

  Further, here, the image size of the reference image may be set larger than the image size of the target image. In this case, the image size of the target image is kept small and the control rate is maintained, and even if the positional displacement amount between the reference image and the target image is large, it is easy to secure a large overlapping area of both images. It becomes easy to correct the deviation. When the movement of the fundus is slow and the control rate of the fundus tracking has a margin, 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 positional deviation due to large movement of the fundus. In other words, by setting the image size of one of the reference image and the target image to be larger than the image size of the other, it becomes easy to correct positional deviation due to a large movement of the fundus.

(Procedure for photographing the fundus)
Next, with reference to FIG. 3, the procedure for photographing the fundus in the fundus imaging device 100 will be described. FIG. 3 is a flowchart of the photographing procedure of the fundus according to the present embodiment.

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

  In step S302, the control unit 190 controls the imaging unit provided with the OCT optical system and the SLO optical system based on the image of the anterior segment displayed on the display unit with respect to the eye E to be examined, X, Y, and Perform alignment in the Z direction (front eye XYZ alignment). Specifically, the examiner observes the image of the anterior segment, and the control unit 190 controls a drive mechanism (not shown) of the imaging unit according to the examiner's input to Perform alignment. As described above, the anterior eye observation camera 193 is adjusted in position in the X, Y, and Z directions 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 match, thereby the OCT optical system Alignment of the system and SLO optics in the X, Y, and Z directions can be performed. The position alignment of the imaging unit may be performed by the examiner operating a drive mechanism of the imaging unit (not shown).

  When the anterior eye XYZ alignment is completed, in step S303, in response to the examiner pressing the anterior eye illumination light source button displayed on the display unit again, the control unit 190 extinguishes the anterior eye illumination light source.

  When the anterior eye illumination light source is turned off, the controller 190 controls the light source 101 of the OCT optical system and the SLO optical system in response to the examiner pressing the light source button (not shown) displayed on the display unit in step S304. The light source 102 is turned on. The timing at which the light source 101 of the OCT optical system is turned on is not limited to this. For example, the light source 101 may be turned on after the rough focus adjustment in step S305 described later.

  When the light source 102 of the SLO optical system is turned on, the control unit 190 generates a fundus planar image based on the output of the light receiving element 192 and causes the display unit to display the same. In step S305, the control unit 190 roughly adjusts the focus (rough focus adjustment) of the SLO optical system and the OCT optical system in accordance with the examiner's input based on the fundus oculi plane image displayed on the display unit.

  Specifically, the controller 190 moves the motorized stage 126 in response to the examiner observing the fundus oculi plane image and moving the focus adjustment bar (not shown) displayed on the display unit. The motorized stage 126 and the mirrors 119 and 120 are disposed in the common optical path of the OCT measurement light 104 and the SLO measurement light 106, and by performing the focus adjustment of the SLO measurement light 106, the OCT measurement light 104 is also rough focus adjusted simultaneously. Is done. Here, focus adjustment is performed such that the luminance of the fundus planar image is maximized.

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

  After performing the rough focus adjustment, in step S306, the control unit 190 responds to the examiner's input based on the position of the Hartmann image of the wavefront sensor 181 displayed on the display unit. I do. In the XY fine alignment, the examiner observes the position of the Hartmann image of the wavefront sensor 181 displayed on the display unit, and the control unit 190 responds to the examiner's input with respect to the eye E to be examined. Perform precise alignment of directions.

  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 subject eye E so that the Hartmann image is in the center of the wavefront sensor 181, thereby aligning the X and Y directions of the OCT optical system and the SLO optical system. It can be performed. In the display unit, an index or the like corresponding to the center position of the wavefront sensor 181 and a Hartmann image may be displayed.

  After the XY fine alignment is performed, the controller 190 starts wavefront correction by the deformable mirror 182 in response to the examiner pressing a wavefront correction button (not shown) displayed on the display unit in step S307. Here, the control unit 190 deforms the shape of the deformable mirror 182 based on the aberration measured by the wavefront sensor 181, and corrects 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 the common optical path of the OCT measurement light 104 and the SLO measurement light 106. Therefore, by correcting the aberration of the eye E by deforming the shape of the deformable mirror 182 for the OCT measurement light 104, the aberration of the eye E can also be corrected for the SLO measurement light 106.

  When wavefront correction is started, the controller 190 adjusts the optical path length of the reference beam 103 in step S308. Specifically, in response to the examiner moving the reference optical path length adjustment bar (not shown) displayed on the display unit, the control unit 190 controls the motorized stage 125 to adjust the optical path length of the reference light 103. Do. Here, the control unit 190 displays the tomographic image acquired using the OCT optical system on the display unit, and according to the input by the examiner, the image of the desired layer in the tomographic image is in the tomographic image display area. The optical path length of the reference beam 103 is adjusted to fit the desired position.

  When the optical path length of the reference light 103 is adjusted, in step S309, the control unit 190 performs fine focus adjustment of the OCT optical system. Specifically, in response to the examiner moving the focus adjustment bar (not shown) displayed on the display unit based on the tomographic image, the control unit 190 controls the motorized stage 126 to make the OCT optical system finer Adjust the focus. In the optical system of the high optical resolution of the compensation optical OCT, it is difficult to simultaneously focus all over the depth direction of the retina Er because the measurement light at the fundus has a large NA and a shallow depth of focus. Therefore, in step S309, fine focus adjustment is performed so that the OCT measurement light 104 is focused on the layer of the retina Er to be particularly photographed. For example, when it is desired to image a blood vessel in the surface layer of the retina, the control unit 190 controls the motorized stage 126 to adjust the focus of the OCT measurement light 104 so that the brightness of the portion becomes maximum.

  When the OCT measurement light 104 is adjusted to a desired focus state by fine focus adjustment, in step S310, the control unit 190 performs SLO fine focus adjustment based on the fundus planar image acquired using the SLO optical system. Specifically, control unit 190 controls motorized stage 127 in response to the examiner moving the SLO focus adjustment bar (not shown) displayed on the display unit. Here, focus adjustment is performed so that the contrast of the photoreceptors of the fundus oculi plane image displayed on the display unit becomes high. The focusing position of the SLO optical system is not limited to the photoreceptor. The focusing position of the SLO optical system may be a position having another feature point such as a blood vessel, if desired tracking accuracy can be achieved.

  The focus lens 157 mounted on the motorized stage 127 is disposed in the dedicated optical path of the SLO optical system branched from the common optical path with the OCT optical system. Therefore, by changing the position of the focus lens 157 by the motorized stage 127, the focus of the SLO optical system can be adjusted without affecting the focus state of the OCT optical system.

  Further, the focusing lens 157 is disposed in the common optical path of the SLO measurement light 106 and the SLO return light 107. Thus, the focal position of the SLO measurement light 106 can be adjusted to the desired position of the retina Er, and at the same time the focal position of the SLO return light 107 from that position can be adjusted to the pinhole position of the pinhole plate 178.

  The focus adjustment of the SLO optical system may also be performed by moving the lens 155 disposed in the dedicated light path of the SLO measurement light 106 and the lens 156 disposed in the dedicated light path of the SLO return light 107 in the optical axis direction. it can. However, in that case, it is necessary to control the positions of the lens 155 and the lens 156, respectively, which complicates the apparatus configuration and control. On the other hand, when focus adjustment of the SLO optical system is performed using the focus lens 157, the apparatus configuration and control can be simplified.

  After the SLO fine focus adjustment, in step S311, the control unit 190 starts fundus tracking in response to the examiner pressing a tracking button (not shown) displayed on the display unit. As described above, the control unit 190 that functions as eye movement detection means calculates the amount of positional deviation from the feature points of the fundus planar image acquired using the SLO optical system, and based on the calculated amount of deviation, the X scanner 132 and The fundus tracking is performed by controlling the Y scanner 133. As a result, the fundus imaging device 100 can acquire a plurality of tomographic images, moving images, 3D volume images, and the like used for noise processing by superposition of tomographic images with a small positional deviation.

  When tracking is started, in step S312, in response to the examiner pressing an imaging button (not shown) displayed on the display unit, the control unit 190 acquires a fundus tomographic image and a fundus planar image. 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 the control unit 190 stores and processes data. The control unit 190 processes the data based on the interference light to generate a fundus tomographic image. 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 the control unit 190 stores and processes data. The control unit 190 processes the data based on the SLO return light 107 to generate a fundus planar image.

  In this embodiment, while performing accurate fundus tracking using the fundus planar image acquired using the optical system of the adaptive optics SLO, the optical system of the adaptive optical OCT is used to focus on a desired layer of the retina Er. In addition, it is possible to take a fundus tomographic image with high resolution and good SN ratio. In addition, since aberration fluctuation due to movement of the focus lens 157 in the SLO optical system does not affect the OCT optical system, a fundus tomographic image can be acquired using the OCT optical system while aberration correction is accurately performed.

  As described above, the fundus imaging apparatus 100 according to the present embodiment uses the OCT measurement light 104 to acquire tomographic information of the eye E, and the SLO measurement light 106 to use the fundus information of the eye E to be examined. And SLO optics to acquire. Further, the fundus imaging apparatus 100 includes a common optical path in which the OCT optical system and the SLO optical system share at least a part of the optical paths of the OCT measurement light 104 and the SLO measurement light 106, and mirrors 119 and 120 provided in the common optical path. The system comprises a modal optical system. Furthermore, the fundus imaging device 100 includes a focus lens 157 provided in the optical path of the SLO measurement light 106 branched from the common optical path. Here, the focus adjustment range by the focus lens 157 is narrower than the focus adjustment range by the badal optical system.

  In addition, the fundus imaging apparatus 100 is provided in a common optical path, and is provided in a common optical path, and is provided in a common optical path, and a control unit 190 that controls a modal optical system and a focus lens 157, a wavefront sensor 181 that measures an aberration of return light of A deformable mirror 182 is provided. The control unit 190 controls the change in the shape of the deformable mirror based on the aberration measured by the wavefront sensor 181.

  Further, the fundus imaging apparatus 100 includes an X scanner 132 and a Y scanner 133 which scan the OCT measurement light 104 in a two-dimensional direction on the fundus of the eye to be examined. The controller 190 detects the movement of the fundus based on the fundus information of the subject eye E acquired using the SLO optical system, and controls the X scanner 132 and the Y scanner 133 based on the detected movement of the fundus.

  From such a configuration, the fundus imaging device 100 can adjust the focus positions of the OCT optical system and the SLO optical system to different positions while having a compact device configuration. Therefore, in the fundus imaging apparatus 100, the focal position of the optical system of the adaptive optics OCT is aligned with the layer to be photographed, and the focal position of the optical system of the adaptive optics SLO is a feature point advantageous for position detection for fundus tracking. It can be combined with many layers. As a result, while performing fundus tracking with high accuracy using the optical system of the adaptive optics SLO, it is possible to capture a high lateral resolution tomographic image with the optical system of the adaptive optical OCT. Therefore, it is possible to acquire a plurality of tomographic images, moving images, and 3D volume images while suppressing positional deviation during imaging.

  Further, the fundus imaging apparatus 100 according to the present embodiment includes a Y scanner 133 that scans the OCT measurement light 104 and the SLO measurement light 106 in the Y direction (first scanning direction), and an X measurement perpendicular to the OCT measurement light 104 in the Y direction. An X scanner 132 is provided which scans in the direction (second scanning direction). Furthermore, the fundus imaging device 100 includes an X scanner 131 that scans the SLO measurement light 106 in the X direction. Here, the control unit 190 causes the Y scanner 133 to repeatedly scan the OCT measurement light 104 and the SLO measurement light 106 while the X scanner 132 performs one scan. The control unit 190 causes the X scanner 131 to repeatedly scan the SLO measurement light 106 while the Y scanner 133 performs one scan.

  The common optical path of the OCT optical system and the SLO optical system includes a dichroic mirror 173 (first dichroic mirror) that separates the OCT measurement light 104 and the SLO measurement light 106. The common light path further includes a dichroic mirror 174 (second dichroic mirror) that combines the OCT measurement light 104 and the SLO measurement light 106 separated by the dichroic mirror 173. Here, the X scanner 132 is disposed in the optical path of the OCT measurement light 104 separated by the dichroic mirror 173, and the X scanner 131 is disposed in the optical path of the similarly separated SLO measurement light 106.

  With such a configuration, the fundus imaging apparatus 100 shares a Y scanner in the OCT optical system and the SLO optical system, so that the apparatus configuration can be made compact as compared to the case where the Y scanner is separately provided in each optical system. it can. Further, since the fundus imaging apparatus 100 uses separate X scanners of the X scanner 132 and the X scanner 131, the imaging ranges in the X direction of the OCT optical system and the SLO optical system can be set independently. Furthermore, the fundus imaging apparatus 100 can rotate the X scanners 131 and 132 in the SLO optical system and the OCT optical system at different cycles, and the scanning speed of the measurement light of the SLO optical system is the scanning speed of the measurement light in the OCT optical system It can be faster.

Second Embodiment
A fundus imaging apparatus 400 according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5.

(Device configuration)
Hereinafter, with reference to FIG. 4, the fundus imaging apparatus 400 according to the present embodiment will be described focusing on differences from the fundus imaging apparatus 100 according to the first embodiment. FIG. 4 shows a schematic configuration of the fundus imaging apparatus 400 according to the present embodiment. In addition, about the structure similar to the fundus imaging device 100 by 1st Embodiment, description is abbreviate | omitted using the same referential mark.

  The basic configuration of the fundus imaging device 400 is the same as that of the fundus imaging device 100 according to the first embodiment. However, the fundus imaging apparatus 400 differs from the fundus imaging apparatus 100 in that the second focusing unit is disposed in the dedicated optical path of the OCT optical system without the second focusing unit disposed in the dedicated optical path of the SLO optical system. In the fundus imaging apparatus 400, a focusing lens 457 as a second focusing unit is disposed in the dedicated optical path of the OCT optical system branched from the common optical path of the OCT optical system and the SLO optical system.

  In the present embodiment, a focusing lens 457 and a lens 458 are provided between the lens 154 and the dichroic mirror 177 in the optical path of the OCT measurement light 104. The focus lens 457 is mounted on the motorized stage 427. The motorized stage 427 can be moved in the optical axis direction of the OCT measurement light 104 as illustrated by the arrow under the control of the control unit 190.

  Although FIG. 4 illustrates the focus lens 457 as a convex lens and the lens 458 as a concave lens, the configuration of the focus lens 457 and the lens 458 is not limited to this. The focus lens 457 may be a concave lens, and the lens 458 may be a convex lens, or both may be convex lenses and an intermediate image may be formed therebetween.

(Procedure for photographing the fundus)
Next, with reference to FIG. 5, the procedure for photographing the fundus in the fundus imaging device 400 of the present embodiment will be described. FIG. 5 is a flowchart of the photographing procedure of the fundus according to the present embodiment. Steps S501 to S507 are the same as steps S301 to S307 in the photographing procedure according to the first embodiment, and therefore the description thereof is omitted.

  When imaging is started and alignment, rough focus adjustment, and wavefront correction start are performed in steps S501 to S507 in the same manner as in steps S301 to S307 in the first embodiment, the process proceeds to step S508.

  In step S508, the control unit 190 performs fine focus adjustment of the SLO optical system. Specifically, in response to the examiner moving the focus adjustment bar (not shown) displayed on the display unit based on the fundus planar image, the control unit 190 controls the motorized stage 126 to set the SLO optical system. Make fine focus adjustments. In step S508, focus adjustment is performed so that the contrast of the photoreceptors of the fundus oculi plane image displayed on the display unit becomes high. The focusing position of the SLO optical system is not limited to the photoreceptor. The focusing position of the SLO optical system may be a position having another feature point such as a blood vessel, if desired tracking accuracy can be achieved.

  Further, at this time, the control unit 190 arranges the motorized stage 427 provided in the OCT optical system at the position of the preset initial state. Here, as the position of the motorized stage 427 in the initial state, the position of the motorized stage 427 is set such that the focus positions of the OCT measurement light 104 and the SLO measurement light 106 substantially coincide with each other.

  If adjustment is performed so that the contrast of the photoreceptor is maximized by fine focus adjustment, the control unit 190 starts fundus tracking in step S509, as in step S311 of the first embodiment. Thereafter, in step S510, the control unit 190 adjusts the reference optical path length as in step S308 of the first embodiment.

  After adjusting the reference optical path length, in step S511, the control unit 190 performs OCT fine focus adjustment. Specifically, in response to the examiner moving the OCT focus adjustment bar (not shown) displayed on the display unit based on the tomographic image, the control unit 190 controls the motorized stage 427 to set the focus lens 457. Move and perform fine focus adjustment of the OCT optical system. Here, focus adjustment is performed so that the luminance of the layer desired to be captured in the tomographic image displayed on the display unit is maximized.

  In the present embodiment, the focus lens 457 is disposed in the dedicated optical path of the OCT optical system branched from the common optical path with the SLO optical system. Therefore, by changing the position of the focus lens 457 by the motorized stage 427, the focus of the OCT optical system can be adjusted without affecting the focus state of the SLO optical system.

  When the brightness of the desired layer is maximized by the OCT fine focus adjustment, in step S512, imaging is performed in the same procedure as step S312 in the first embodiment.

  As described above, the fundus imaging apparatus 400 according to the present embodiment includes the focus lens 457 serving as the second focusing unit in the optical path of the OCT measurement light 104 in the OCT optical system branched from the common optical path. Even with such a configuration, the fundus imaging device 400 can adjust the focal positions of the OCT optical system and the SLO optical system to different positions while having a compact device configuration.

  Therefore, similarly to the fundus imaging apparatus 100 according to the first embodiment, the fundus imaging apparatus 400 according to the present embodiment focuses on a desired layer with the OCT optical system to achieve high resolution while performing accurate fundus tracking. I can shoot. In addition, in the fundus imaging apparatus 400, the focus of the OCT optical system can be changed to a different layer while performing fundus tracking using the SLO optical system. For example, tomographic images at a plurality of focus positions of the OCT optical system The operation becomes easy when shooting a picture.

[Modification 1]
In the first and second embodiments, the mirrors 119 and 120 mounted on the motorized 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 roughened by moving them. Focus adjustment and fine focus adjustment were performed. However, the first focusing means used for these focus adjustments is not limited to this. For example, it is also possible to use a deformable mirror 182 disposed in the common optical path of the OCT optical system and the SLO optical system as the first focusing means.

  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 an offset of the defocus component. 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. Also in rough focus adjustment, the deformable mirror 182 can be similarly used when the amount of focus adjustment can be reduced.

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

[Modification 2]
Further, in the first and second embodiments, the focus adjustment is performed by independently controlling the first focusing means and the second focusing means. However, the fundus imaging apparatus comprises the first focusing means and the second focusing means. It may have a mode in which the focusing means is interlocked and controlled.

  The apparatus configuration in this case is the same as that of the fundus imaging apparatus 100 shown in FIG. 1, and the photographing procedure of the fundus is the same as that of the flowchart in FIG. However, the present embodiment is different in that at the time of OCT fine focus adjustment (step S511), the first focusing unit and the second focusing unit are controlled in conjunction with each other.

  In this case, in step S508, the control unit 190 controls the motorized stage 126 to move the focus lens 157 to perform fine focus adjustment of the SLO optical system. After that, in step S511, when moving the motorized stage 126 to perform OCT fine focus adjustment, the motorized stage 127 disposed in the dedicated optical path of the SLO optical system is operated to cancel the adjustment by the motorized stage 126. Control. In other words, at the time of OCT fine focus adjustment by the first focusing unit disposed in the common optical path, the control unit 190 sets the second focusing unit disposed in the dedicated optical path in the direction to cancel the influence of the adjustment. Operate in conjunction with the focusing means. Thereby, the focus adjustment of the OCT optical system can be performed without changing the focus state of the SLO optical system.

  Thereafter, when the brightness of the desired layer is maximized by the OCT fine focus adjustment, in step S512, the control unit 190 performs imaging in the same manner as in step S312 in the first embodiment.

  Even in this case, while performing fundus tracking with high accuracy, an optical system of adaptive optics OCT can focus on a desired layer to capture an image with a high SN ratio at high resolution. In addition, since focusing of the optical system of the adaptive optics OCT can be changed to a different layer while fundus tracking is performed using the optical system of the adaptive optics SLO, for example, in the case of imaging at a plurality of focus positions Operation becomes easy. In addition, since aberration fluctuation due to movement of the focus lens 157 mounted on the motorized stage 127 does not affect the OCT optical system, a fundus tomographic image can be acquired using the optical system of the adaptive optics OCT while aberration correction is accurately performed. Further, in the configuration of the fundus imaging apparatus 400, the same processing can be performed when performing the imaging procedure of the fundus described in the flowchart of FIG.

  The focus adjustment may be performed by deforming the deformable mirror 182 as a first focusing unit. In this case, an offset of the defocus component is given to the target shape of the deformable mirror 182 for control, and the motorized stage 127 as the second focusing means may be controlled to cancel the offset amount.

  Further, an interlocking mechanism may be provided for interlocking the first focusing means and the second focusing means. In this case, the control unit 190 can interlock the first focusing unit and the second focusing unit by controlling the interlocking mechanism. Further, the interlocking mechanism may be configured to be capable of releasing the interlocking between the first focusing means and the second focusing means. In this case, the control unit 190 releases the interlocking by the interlocking mechanism and the first focusing means and the first focusing means The two focusing means can be controlled separately.

[Modification 3]
When rough focus adjustment is performed in step S305 of the first embodiment and step S505 of the second embodiment, the adjustment of the optical path length adjusting means provided in the reference light path and the focus adjustment by the first focusing means are interlocked It may be controlled.

  In this case, the control unit 190 moves the mirror 124 by controlling the motorized stage 125 so that the optical path length changes by substantially the same amount as the optical path length change amount due to the movement of the mirrors 119 and 120 during rough focus adjustment. Thereby, the focus can be adjusted without changing the optical path length difference between the OCT measurement light 104 and the reference light 103. Therefore, the movement amount of the mirror 124 at the time of performing the reference optical path length adjustment in step S308 of the first embodiment and step S510 of the second embodiment can be reduced. When the movement amount of the mirror 124 mounted on the motorized stage 125 is small, the adjustment time of the optical path length can be shortened, and the total imaging time from the start of the operation to the completion of the imaging can be shortened. The burden can be reduced.

  Further, an interlocking mechanism may be provided to interlock the optical path length adjusting means with the first focusing means. In this case, the control unit 190 can interlock the mirror 124 mounted on the motorized stage 125 and the first focusing unit by controlling the interlocking mechanism. Further, the interlocking mechanism may be configured to be able to release interlocking between the optical path length adjusting means and the first focusing means, and in this case, the control unit 190 releases interlocking by the interlocking mechanism and the optical path length adjusting means and the first Can be controlled separately.

  In the first and second embodiments, the optical path length adjusting means is constituted by the mirror 124 provided in the optical path of the reference beam 103. However, the optical path length adjusting means may be provided in the optical path of the OCT measurement light 104.

[Modification 4]
In the first and second embodiments, the second focusing means is provided in one of the dedicated optical path of the OCT optical system and the dedicated optical path of the SLO optical system. However, the second focusing means may be provided both in the dedicated light path of the OCT optical system and in the dedicated light path of the SLO optical system. As described above, the second focusing means is used for fine focus adjustment of each optical system because the focus adjustment range is narrower than the first focusing means and the diopter range of the subject eye E that can be handled is narrow. . In this modification, in the imaging procedure, fine focusing after rough focusing is separately performed by second focusing means respectively provided in the dedicated light path of the OCT optical system and the dedicated light path of the SLO optical system.

  Even in such a case, since the second focus means has a narrower focus adjustment range than the first focus means, for example, the movement range of the motorized stage on which the focus lens is mounted can be narrowed. Thus, the device configuration can be made compact. Also, the second focusing means is not limited to the motorized stage equipped with the focusing lens. For example, the second focusing means may be configured of an electro-optical element such as a crystal of potassium tantalate niobate, or another piezo element capable of obtaining the same effect, a liquid crystal optical element, a deformable mirror, or the like. . In this case, since it is not necessary to secure the movement range of the motorized stage, the apparatus configuration can be made more compact.

  In the embodiment and the modification, the control unit 190 performs various alignments, optical path length adjustment, and focus adjustment in accordance with the input of the examiner. However, based on the various alignments described above, the adjustment of the optical path length, the image of the anterior segment used in the focus adjustment, the fundus planar image, the Hartmann image, the tomographic image, etc., the control unit 190 automatically performs these alignments. Adjustments may be made. In this case, for example, similar to the alignment and adjustment described above, the control unit 190 can perform the alignment and adjustment on the basis of the luminance of the fundus planar image, the layer to be photographed, and the like.

  Further, in the above embodiment and modification, the configuration of the Michelson interferometer is used as the interference optical system of the fundus imaging device, but the configuration of the interference optical system is not limited to this. For example, the interference optical system of the fundus imaging apparatus may have the configuration of a Mach-Zehnder interferometer. Further, the wavelength of the light reflected or transmitted by each dichroic mirror in the above embodiment and modified example is arbitrary, and may be configured to reflect or transmit light opposite to the above configuration.

  Furthermore, although the Y scanner 133 is shared in the OCT optical system and the SLO optical system in the above embodiment and the modification, Y scanners may be separately provided in the OCT optical system and the SLO optical system. In addition, the first focusing unit disposed in the common optical path is not limited to the configuration disposed between the Y scanner 133 and the X scanners 131 and 132. For example, at least one of the X scanners 131 and 132 may be provided between the eye E and the first focusing means. In addition, the Y scanner 133 may not be provided between the eye E and the first focusing unit.

  Furthermore, in the above embodiment and modification, a spectral domain OCT (SD-OCT) optical system using an SLD as a light source has been described as an OCT optical system, but 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-swept 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 implements one or more functions of the above-described embodiments to a system or apparatus via a network or storage medium, and one or more processors in a computer of the system or apparatus read and execute the program. Can also be realized. It can also be implemented by a circuit (eg, an ASIC) that implements one or more functions.

  As mentioned above, although this invention was demonstrated with reference to embodiment, this invention is not limited to the said embodiment. Inventions modified without departing from the spirit of the present invention and inventions equivalent to the present invention are also included in the present invention. Moreover, the above-mentioned each embodiment and modification can be combined suitably in the range which does not violate the meaning of the present invention. Further, not all combinations of the features described in the embodiments and the modifications are necessarily essential to the solution means of the present invention.

100: fundus imaging device, 101, 102: light source, 119, 120: mirror, 126, 127: motorized stage, 157: focus lens, 173, 174, 177: dichroic mirror, 191: line camera, 192: light receiving element, E : Subject's eye

Claims (16)

An OCT optical system that acquires tomographic information of an eye to be examined using OCT measurement light;
An SLO optical system that acquires fundus information of the subject's eye using SLO measurement light;
A common optical path in which the OCT optical system and the SLO optical system share at least a part of the optical paths of the OCT measurement light and the SLO measurement light;
First focusing means provided in the common optical path;
A second focusing unit provided on at least one of the optical path of the SLO measurement light branched from the common optical path and the optical path of the OCT measurement light;
A fundus imaging apparatus comprising:   The fundus imaging apparatus according to claim 1, wherein a focus adjustment range by the second focusing unit is narrower than a focus adjustment range by the first focusing unit.   The fundus imaging apparatus according to claim 1, wherein the second focusing unit is provided in an optical path of the SLO measurement light branched from the common optical path.   The fundus imaging apparatus according to any one of claims 1 to 3, further comprising control means for controlling the first focusing means and the second focusing means. Aberration measurement means for measuring the aberration of the OCT measurement light;
Aberration correction means provided in the common optical path for correcting the aberration;
And further
The fundus imaging apparatus according to claim 4, wherein the control unit controls the aberration correction unit based on the aberration measured by the aberration measurement unit.   The fundus oculi according to claim 5, wherein the first focusing means is a paradox optical system comprising a reflection optical system provided in the light path between the aberration measuring means and the aberration correcting means and the eye to be examined. Imaging device.   The fundus imaging apparatus according to any one of claims 4 to 6, wherein the control unit controls the second focusing unit in conjunction with the first focusing unit. The optical path length adjustment means provided in one of the optical path of the OCT measurement light and the optical path of the reference light corresponding to the OCT measurement light in the OCT optical system is further provided.
The fundus imaging apparatus according to any one of claims 4 to 7, wherein the control means controls the optical path length adjusting means in conjunction with the first focusing means. It further comprises scanning means for scanning the OCT measurement light in a two-dimensional direction on the fundus of the eye to be examined,
The control means
Detecting movement of the fundus based on the fundus information of the eye to be examined;
The fundus imaging apparatus according to any one of claims 4 to 8, wherein the scanning unit is controlled based on the detected movement of the fundus. The control means is configured to generate a reference image which is a partial image of a planar image based on the first fundus information acquired by the SLO optical system, and a second image acquired by the SLO optical system after the first fundus information. The movement of the fundus is detected by detecting positional deviation from a target image which is a partial image of a planar image based on fundus information,
The fundus imaging apparatus according to claim 9, wherein the image size of one of the reference image and the target image is larger than the image size of the other. First scanning means for scanning the OCT measurement light and the SLO measurement light in a first scanning direction;
Second scanning means for scanning the OCT measurement light in a second scanning direction perpendicular to the first scanning direction;
Third scanning means for scanning the SLO measurement light in the second scanning direction;
And further
The control means causes the first scanning means to repeatedly scan the OCT measurement light and the SLO measurement light while performing one scan by the second scanning means, and one of the first scanning means. The fundus imaging apparatus according to any one of claims 4 to 8, wherein the SLO measurement light is repeatedly scanned by the third scanning means during one round of scanning. The common light path is
A first dichroic mirror that separates the OCT measurement light and the SLO measurement light;
A second dichroic mirror that combines the OCT measurement light and the SLO measurement light separated by the first dichroic mirror;
Including
The second scanning means is disposed in the optical path of the separated OCT measurement light,
The fundus imaging apparatus according to claim 11, wherein the third scanning unit is disposed in the optical path of the separated SLO measurement light.   13. The apparatus according to claim 11, wherein at least one of the first scanning unit, the second scanning unit, and the third scanning unit is disposed between the eye to be examined and the first focusing unit. Fundus imaging device. The control means
After the focus states of the OCT measurement light and the SLO measurement light are adjusted by the first focusing means, the focus state of at least one of the OCT measurement light and the SLO measurement light is further adjusted by the second focusing means. The fundus imaging apparatus according to any one of claims 4 to 13. It further comprises an interlocking mechanism that interlocks the second focusing means and the first focusing means,
The fundus imaging apparatus according to any one of claims 1 to 3, wherein the interlocking mechanism can release interlocking of the second focusing unit and the first focusing unit. An optical path length adjusting means provided in one of the optical path of the OCT measurement light and the optical path of the reference light corresponding to the OCT measurement light in the OCT optical system;
An interlocking mechanism for interlocking the optical path length adjusting means and the first focusing means;
And further
The fundus imaging apparatus according to any one of claims 1 to 3, wherein the interlocking mechanism can release interlocking of the optical path length adjusting unit and the first focusing unit.

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