Ophthalmic observation device

Abstract

Ophthalmic observation device which features: an optical photography system comprising a first focusing lens and performing photography to capture a front image of an eye; an optical measuring system that includes a second focusing lens and performs optical coherence tomography (OCT) to capture a cross-sectional image of the eye; an optical path coupler that couples the optical paths of the optical photography system and the optical measuring system at one point on the eye side of the first and second focusing lenses; a first drive to move the first focusing lens along an optical axis of the optical photography system; a second drive for moving the second focusing lens along an optical axis of the optical measuring system; and a control system that individually controls the first and second drives, wherein the optical measurement system OCT performs the acquisition of a cross-sectional image of the fundus of the eye, and which further comprises: an optical projection system that projects a focusing index onto the fundus as an indication of a focus state of the optical photography system on the fundus; and an intensity reference element that references the intensity of an interference signal detected by the optical measurement system, wherein After focusing the optical photography system and focusing the optical measuring system based on the focusing index, the control system controls the second drive based on the intensity referenced by the intensity reference element. wherein the controller acquires multiple interference signals corresponding to multiple positions of the second focusing lens by controlling the optical measuring system while controlling the second drive to move the second focusing lens, has a fourth target position reference part which obtains a target position of the second focusing lens based on intensities of the multiple interference signals obtained by the intensity reference part, and controls the second drive to move the second focusing lens to the obtained target position.

Description

Technical field

[0001] The invention relates to an ophthalmological observation device that captures images of an eye. Background of the technology

[0002] In recent years, optical coherence tomography (OCT) has gained attention for generating images that depict the superficial and / or internal morphology of objects using light beams from laser light sources, etc. Unlike X-ray CT, optical coherence tomography is non-invasive for the human body, which is why its use is anticipated, particularly in the medical and biological fields. For example, devices for generating images of the fundus (back of the eye), cornea, etc., are already in practical use in ophthalmology.

[0003] A device disclosed in JP H11 325849 A uses the so-called "Fourier-domain OCT" (Fourier-range OCT) technique. Specifically, this device emits a low-coherence light beam onto an object, superimposes its reflected light and reference light to generate interference light, and records the spectral intensity distribution of the interference light. It then performs a Fourier transform to image the morphology in the depth direction (z-direction) of the object. Furthermore, this device is equipped with a galvo mirror for scanning with light beams (signal light) in a direction (x-direction) perpendicular to the z-direction, producing an image of a desired target measurement region of the object. An image produced by this device is a two-dimensional cross-sectional image in the depth direction (z-direction) and scan direction (x-direction) of the light beam. This technique is specifically referred to as "spectral domain" (spectral-range OCT).

[0004] JP 2002-139421 A discloses a technique that scans with signal light in the horizontal and vertical directions (x-direction and y-direction) to generate two-dimensional cross-sectional images in the horizontal direction and acquires three-dimensional cross-sectional information of a measurement area based on these cross-sectional images to perform imaging. Such a three-dimensional imaging technique includes, for example, a method that arranges and displays cross-sectional images in the vertical direction (called batch data, etc.) and a method that performs rendering (synthesis) processing on volume data (voxel data) formed from batch data to generate a three-dimensional image.

[0005] JP 2007-24677 A and JP 2006-153838 A disclose other types of OCT. An OCT device disclosed in JP 2007-24677 A scans with wavelengths of light illuminating an object (wavelength sweeping), detects interference light obtained by superimposing reference light with reflected light of the respective wavelengths to capture a spectral intensity distribution, and performs a Fourier transform on this to map the morphology of an object. Such an OCT technique is called "swept-source" OCT, etc. Swept-source OCT is a type of Fourier-domain OCT.

[0006] An OCT device disclosed in JP 2006-153838 A emits light with a predetermined beam diameter onto an object and analyzes components of interference light obtained by superimposing its reflected light and reference light, thereby generating an image of a cross-section of the object orthogonal to the direction of illumination. Such an OCT technique is called "full-field," "en-face" (full-field OCT, en-face OCT), etc.

[0007] JP2008-73099 A discloses an example of OCT application in ophthalmology. Before the use of OCT, retinal cameras, slit-lamp microscopes, scan laser ophthalmoscopes (SLOs), etc., were used to observe eyes (see, for example, JP H09-276232 A, JP 2008-259544 A, and JP 2009-11381 A). Retinal cameras photograph the fundus by shining illumination light onto an eye and receiving reflected light from the fundus. Slit-lamp microscopes obtain a cross-sectional image of the cornea by cutting a section of the cornea using slit light. The SLO images the morphology of the retinal surface by scanning the fundus with laser light and detecting reflected light using highly sensitive elements, such as a photomultiplier. These modalities photograph the fundus, cornea, etc. from the front to capture images (frontal images).

[0008] OCT devices have advantages over retinal cameras, etc., because high-resolution images can be obtained, cross-sectional and three-dimensional images can be obtained, etc.

[0009] Since OCT devices are used to observe different parts of the eye and can thus obtain high-resolution images, they are used in the diagnosis of various ophthalmological disorders.

[0010] Further state of the art is disclosed in JP 2011-245183 A, JP 2009-291252 A, US 2010 / 0165291 A1 and US 2009 / 0244483 A1. Summary of the invention Problems to be solved by the invention

[0011] As in the device disclosed, for example, in JP2008-73099 A, conventional ophthalmic observation devices that can capture both frontal images and OCT images use one or more common focusing lenses for the optical system for capturing frontal images and the optical system for OCT.

[0012] However, since light wavelengths for front image acquisition (e.g. visible light) and light wavelengths for OCT (e.g. near-infrared light) differ from each other, optimal focus positions for these modalities also differ.

[0013] If a focusing lens is set at an optimal focus position for front image acquisition, OCT cannot be performed with optimal focus conditions. Conversely, if a focusing lens is set at an optimal focus position for OCT, front image acquisition with optimal focus conditions cannot be performed.

[0014] One object of the invention is to provide a technique that can perform both frontal image acquisition and OCT of an eye under suitable focus conditions. Problem-solving approach

[0015] To solve this problem, the invention provides an ophthalmological observation device according to claim 1.

[0016] The invention described in claim 2 is the ophthalmological observation device according to claim 1, wherein the fourth target position reference part specifies the maximum intensity among the intensities of the multiple interference signals and defines a position of the second focusing lens corresponding to the specified maximum intensity as the target position.

[0017] The invention described in claim 3 is the ophthalmological observation device according to claim 1 or 2, wherein the control moves the second focusing lens in a predetermined area to detect the multiple interference signals.

[0018] The invention described in claim 4 is the ophthalmological observation device according to claim 3, wherein the predetermined area has a position of the second focusing lens which is predetermined on the basis of the focusing index.

[0019] The invention described in claim 5 is the ophthalmological observation device according to claim 4, wherein the center of the predetermined area is located at the predetermined position.

[0020] The invention described in claim 6 is the ophthalmological observation device according to any one of claims 1 to 5, which further comprises an optical infrared photography system that uses infrared light to perform photography to capture a front image of a fundus of the eye, wherein the control performs focusing of the optical photography system by moving the first focusing lens and the optical projection system on the basis of the front image that is captured by photographing the fundus, on which the focusing index is projected, using the optical infrared photography system, and performs focusing of the optical measuring system on the basis of the result of this focusing.

[0021] To solve this problem, the invention further provides an ophthalmological observation device according to claim 7. Effect of the invention

[0022] According to the invention, it is possible to perform both frontal image acquisition and OCT of an eye with suitable focus conditions. Brief description of the drawings Fig. Figure 1 is a schematic representation of a configuration example for an ophthalmic observation device according to an example. Fig. Figure 2 is a schematic representation of a configuration example for an ophthalmic observation device according to an example. Fig. Figure 3 is a schematic block diagram of a configuration example for an ophthalmic observation device according to an example. Fig. Figure 4 is a schematic representation to illustrate a configuration example for an ophthalmic observation device according to an example. Fig. 5 is a flowchart of an operational example for an ophthalmic observation device according to an example. Fig. Figure 6 is a schematic block diagram of a configuration example for an ophthalmic observation device according to an example. Fig. Figure 7 is a flowchart of an operational example for an ophthalmic observation device according to an example. Fig. Figure 8 is a schematic block diagram of a configuration example for an ophthalmic observation device according to an example. Fig. Figure 9 is a flowchart of an operational example for an ophthalmic observation device according to an example. Fig. 10 is a flowchart of an operational example for an ophthalmic observation device according to an example. Fig. Figure 11 is a schematic block diagram of a configuration example for an ophthalmic observation device according to one embodiment. Fig. Figure 12 is a flowchart of an operational example for an ophthalmic observation device according to one embodiment. Embodiments of the invention

[0023] Examples of embodiments of ophthalmic observation devices are described in more detail below with reference to the drawings. Ophthalmic observation devices according to these embodiments have a function that uses OCT to acquire cross-sectional and / or three-dimensional images of an eye (fundus, anterior segment, etc.) and a function that photographs the eye to acquire anterior images. In this description, images acquired by OCT are sometimes referred to as OCT images. Furthermore, a measurement operation for generating OCT images is sometimes referred to as OCT (measurement). The content disclosed in the documents cited in this description can be applied to the following embodiments.

[0024] The following embodiments describe in more detail configurations in which Fourier-domain OCT is used. In particular, ophthalmic observation devices described later can obtain OCT images using spectral-domain OCT, such as the device disclosed in JP2008-73099 A. Configurations according to the invention can be applied to ophthalmic observation devices of any type other than spectral-domain OCT (for example, swept-source OCT). The following embodiments describe devices as a combination of an OCT device and a retinal camera; however, an ophthalmic photography device other than a retinal camera, e.g., a SLO, slit-lamp microscope, ophthalmic operating microscope, etc., can be combined with an OCT device. First example configurations

[0025] An ophthalmological observation device 1 according to Fig. 1 and Fig. The device comprises a retinal camera unit 2, an OCT unit 100, and a computing and control unit 200. The retinal camera 2 has virtually the same optical system as a conventional retinal camera. The OCT unit 100 is equipped with an optical system for obtaining OCT fundus images. The computing and control unit 200 includes a computer that performs various arithmetic operations, control processing, and other tasks. Retinal camera unit

[0026] The retinal camera unit 2 according to Fig. 1 is equipped with an optical system for obtaining frontal images (fundus images) as representations of the surface morphology of the fundus (back of the eye) Ef of an eye E. Fundus images include observational images, photographed images, etc. For example, the observational image is a monochromatic moving image generated at a predetermined frame rate using near-infrared light. The photographed image can be, for example, a color image captured by visible flash or a monochromatic still image captured using near-infrared light or visible light as illumination. In addition, the retinal camera unit 2 can acquire other types of images, e.g., fluorescein angiography images, indocyanine green fluorescence images, and autofluorescence images.

[0027] The retinal camera unit 2 is equipped with a chin rest and a head rest for supporting the subject's face. Furthermore, the retinal camera unit 2 is equipped with an optical illumination system 10 and an optical imaging system 30. The optical illumination system 10 emits illumination light onto the fundus Ef. The optical imaging system 30 directs light reflected from the fundus of the illumination light to imaging elements (CCD image sensors 35, 38 (sometimes simply called CCD)). The optical illumination system 10 and the optical imaging system 30 serve as an example of an "optical photography system".

[0028] An observation light source 11 of the optical illumination system 10, for example, comprises a halogen lamp. Light emitted by the observation light source 11 (observation illumination light) is reflected by a reflecting mirror 12 with a curved reflective surface, passes through a condenser lens 13, and becomes near-infrared light after passing through a blocking filter 14 for visible light. Furthermore, the observation illumination light is converged once near an imaging light source 15, reflected by a mirror 16, and passes through relay lenses 17 and 18, an aperture 19, and a relay lens 20. The observation illumination light is then reflected onto a circumferential portion (a region surrounding an aperture portion) of an aperture mirror 21, transmitted through a dichroic mirror 46, and refracted by an objective lens 22, thereby illuminating the fundus Ef. An LED (light-emitting diode) can be used as the observation light source.

[0029] The light from the observation illumination reflected from the fundus is refracted by the objective lens 22, transmitted through the dichroic mirror 46, passes through the aperture segment formed in the central region of the aperture mirror 21, is transmitted through a dichroic mirror 55, passes through a focusing lens 31, and is reflected by a mirror 32. Furthermore, the light reflected from the fundus is transmitted through a half-mirror 39A, reflected by a dichroic mirror 33, and forms an image on a light-receiving surface of the CCD 35 via a condenser lens 34. The CCD 35 detects the light reflected from the fundus, for example, at a preset frame rate. An image (observation image) based on the light reflected from the fundus, detected by the CCD 35, is displayed on a display element 3.When the optical imaging system 30 is focused on the anterior segment of the eye, the observation image of the anterior segment of eye E is displayed. The previously described optical system, which illuminates eye E with observation light and detects its reflected light, is an example of an optical infrared photography system.

[0030] The imaging light source 15, for example, has a xenon lamp. Light (imaging illumination light) emitted by the imaging light source 15 is directed onto the fundus Ef via the same path as the observation illumination light. The light of the imaging illumination light reflected from the fundus is guided to the dichroic mirror 33 via the same path as the observation illumination light, transmitted through the dichroic mirror 33, reflected by a mirror 36, and forms an image on the light-receiving surface of the CCD 38 via a condenser lens 37. An image (photographed or captured image) based on the light reflected from the fundus and detected by the CCD 38 is displayed on the display element 3. The display element 3 for displaying the observation image and the display element 3 for displaying the captured image can be the same or different.When a similar photograph is taken by illuminating eye E with infrared light, an infrared image is displayed. An LED can be used as the imaging light source.

[0031] An LCD (liquid crystal display) 39 shows fixation targets, visual acuity measurement targets, etc. The fixation target is a visual target (index) for fixating the eye E and is used in fundus photography, OCT, etc.

[0032] Part of the light emitted by the LCD 39 is reflected by the half-mirror 39A, reflected by the mirror 32, passes through the focusing lens 31 and the dichroic mirror 55, passes through the aperture portion of the aperture mirror 21, is transmitted through the dichroic mirror 46, refracted by the objective lens 22 and projected onto the fundus Ef.

[0033] By changing the display position of the fixation target on the LCD 39 screen, the fixation position of eye E can be changed. Examples of fixation positions for eye E include the position for capturing an image centered on the macula (the "yellow spot"), the position for capturing an image centered on the optic disc, the position for capturing an image of the fundus center (centered on a point between the macula and optic disc), etc., as with conventional retinal cameras. Display positions of fixation targets can be changed as desired.

[0034] As with conventional retinal cameras, the retinal camera unit 2 has an optical alignment system 50 and an optical focus system 60. The optical alignment system 50 generates a target (index, alignment target) for aligning the position of the optical system with the eye E (i.e., for performing alignment). The optical focus system 60 generates a target (index, split target) for focusing on the fundus Ef.

[0035] Light (alignment light) emitted by an LED 51 of the optical alignment system 50 passes through apertures 52 and 53 and a relay lens 54, is reflected by the dichroic mirror 55, passes through the aperture portion of the aperture mirror 21, is transmitted through the dichroic mirror 46 and is projected onto the cornea of ​​the eye E through the objective lens 22.

[0036] Light from the alignment light, reflected from the cornea, passes through the objective lens 22, the dichroic mirror 46, and the aperture element. A portion of the light reflected from the cornea is then transmitted through the dichroic mirror 55, passes through the focusing lens 31, is reflected by the mirror 32, is transmitted through the half-mirror 39A, is reflected by the dichroic mirror 33, and is projected onto the light-receiving surface of the CCD 35 by the condenser lens 34. An image captured by the CCD 35 (alignment target, alignment index) is displayed on the display element 3 along with the observation image. The user performs the alignment by operating the system as with conventional retinal cameras. Alternatively, the alignment can be performed by the computing and control unit 200 analyzing the position of the alignment target and moving the optical system accordingly (automatic alignment).

[0037] For focus adjustment, a reflective surface of a reflector bar 67 is arranged obliquely in an optical path of the optical illumination system 10. Light emitted by an LED 61 of the optical focusing system 60 (focus light) passes through a relay lens 62, is split into two light streams by a split target plate 63, passes through a two-hole aperture 64, is reflected by a mirror 65, is formed as an image on the reflective surface of the reflector bar 67 by a condenser lens 66, and is then reflected. Furthermore, the focus light passes through the relay lens 20, is reflected at the aperture mirror 21, is transmitted through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef.

[0038] Light from the focus light reflected from the fundus follows the same path as the light from the alignment light reflected from the cornea and is detected by the CCD 35. An image captured by the CCD 35 (split target, split index) is displayed on the display element 3 along with the observation image. As in conventional techniques, the computational control unit 200 analyzes the position of the split target and moves the focusing lens 31 and the optical focusing system 60 to achieve focus (automatic focusing). Focusing can also be performed manually while observing the split target.

[0039] The dichroic mirror 46 couples the optical path to fundus photography and the optical path to OCT. The dichroic mirror 46 reflects light with wavelength bands to the OCT and transmits the light to the fundus photography. The dichroic mirror 46 is an example of an optical path coupler. The optical OCT path includes a collimator lens unit 40, an optical path length changer 41, a galvo scanner 42, a focusing lens 43, a mirror 44, and a relay lens 45. The optical system that forms the optical OCT path and the optical system belonging to the OCT unit 100 is an example of an optical measurement system.

[0040] The optical path length change part 41 is indicated by an arrow in Fig. The optical path length changer 41 is movable in the direction specified in 1 to change the length of the optical OCT path. Changing the optical path length can be used to correct the optical path length in accordance with the axial length of the eye E, to adjust the interference state, etc. For example, the optical path length changer 41 has a triple mirror reflector (“corner cube”) and a mechanism for moving the triple mirror reflector.

[0041] The Galvoscanner 42 reverses the direction of light (signal light LS) guided along the optical OCT path. This allows the fundus Ef to be scanned by the signal light LS. The Galvoscanner 42 comprises a galvo mirror for scanning with signal light LS in the x-direction, a galvo mirror for scanning in the y-direction, and a mechanism for independently driving them. This enables scanning with the signal light LS in any direction within the xy-plane. OCT unit

[0042] Based on Fig. Section 2 describes an example of the configuration of OCT unit 100. OCT unit 100 is equipped with an optical system for acquiring OCT images of the fundus Ef. This optical system has a configuration similar to a conventional spectral-domain OCT device. Specifically, this optical system is configured to split low-coherence light into signal light and reference light, superimpose the signal light returning from the fundus Ef with the reference light that has traversed an optical reference path to generate interference light, and detect spectral components of the interference light. The result of the detection (detection signal) is transmitted to the computing and control unit 200.

[0043] When using swept-source OCT, a wavelength-tunable light source is used instead of a low-coherent light source, while an optical component for spectral decomposition of interference light is not provided. In general, any known technique in accordance with the OCT type can be applied to any configuration of the OCT unit 100.

[0044] A light source unit 101 emits broadband, low-coherent light L0. For example, the low-coherent light L0 contains a near-infrared wavelength band (approximately 800–900 nm) and has a temporal coherence length in the tens of micrometers. It is possible to use wavelength bands invisible to the human eye, e.g., near-infrared light with a center wavelength of approximately 1040–1060 nm, as low-coherent light L0.

[0045] The light source unit 101 includes a light-emitting component, e.g. an SLD (superluminescent diode), an LED, an SOA (optical semiconductor amplifier), etc.

[0046] The low-coherent light L0 emitted by the light source unit 101 is guided to a fiber coupler 103 via an optical fiber (OF) 102 and split into signal light LS and reference light LR.

[0047] The reference light LR is fed to an optical attenuator (attenuator) 105 via an optical fiber 104. Using any known technique, the computing and control unit 200 controls the optical attenuator 105 to automatically adjust the amount of light (light intensity) of the reference light LR guided through the optical fiber 104. The reference light LR, whose light intensity has been adjusted by the optical attenuator 105, is guided through the optical fiber 104 and reaches a polarization control 106. The polarization control 106 applies an external voltage to the optical fiber 104 in a loop to, for example, adjust the polarization state of the reference light LR guided through the optical fiber 104. The configuration of the polarization control 106 is not limited to this, and any known technique can be used.The reference light LR, whose polarization state was set by the polarization control 106, is supplied to an optical coupler 109.

[0048] The signal light LS generated by the fiber coupler 103 is guided via the optical fiber 107 and converted into a parallel luminous flux by the collimator lens unit 40. The signal light LS then passes through the optical path length changer 41, the galvo scanner 42, the focusing lens 43, the mirror 44, and the relay lens 45, reaching the dichroic mirror 46. The signal light LS is also reflected by the dichroic mirror 46, refracted by the objective lens 22, and projected onto the fundus Ef. The signal light LS is scattered (reflected) at various depth positions within the fundus Ef. Backscattered light from the signal light LS at the fundus Ef travels along the same path outwards in the opposite direction to the fiber coupler 103 and reaches the fiber coupler 109 via an optical fiber 108.

[0049] The fiber coupler 109 superimposes the backscattered light of the signal light LS and the reference light LR, which has passed through the optical fiber 104. The interference light LC thus generated is guided through an optical fiber 110 and emitted from an exit end 111. Furthermore, the interference light LC is converted into a parallel luminous flux by a collimator lens 112, spectrally split (spectrally decomposed) by a diffraction grating 113, converged by a condenser lens 114, and projected onto the light-receiving surface of a CCD (image sensor) 115. Although the diffraction grating 113 according to Fig. If the element is of the transmission type, all other types of spectrally decomposing elements (e.g., of the reflection type) can be used.

[0050] The CCD 115, for example, is a line sensor that detects the individual spectral components of the spectrally decomposed interference light LC and converts these components into electrical charges. The CCD 115 accumulates these electrical charges, generates detection signals, and transmits them to the processing and control unit 200.

[0051] Although a Michelson interferometer is used in this example, any type of interferometer can be used if needed, e.g., a Mach-Zehnder type. Instead of the CCD, other types of image sensors can be used, e.g., CMOS (complementary metal-oxide semiconductor). Computing and control unit

[0052] The following describes a configuration of the Computing and Control Unit 200. The Computing and Control Unit 200 analyzes detection signals input from the CCD 115 to generate OCT images of the fundus Ef. The computational processing for this can be the same as in the conventional spectral-domain OCT device.

[0053] The computing and control unit 200 controls each part of the retinal camera unit 2, the display unit 3, and the OCT unit 100. For example, the computing and control unit 200 displays OCT images of the fundus Ef on the display unit 3.

[0054] The computer and control unit 200 operates as the controllers of the retinal camera unit 2: action controls of the observation light source 101, the imaging light source 103 and the LEDs 51 and 61; action control of the LCD 39; movement controls of the focusing lenses 31 and 43; movement control of the reflection bar 67; movement control of the optical focusing system 60; movement control of the optical path length changer 41; action control of the galvo scanner 42, etc.

[0055] The computing and control unit 200 acts as the controller of the OCT unit 100: action control of the light source unit 101; action control of the optical damper 105; action control of the polarization control 106; action control of the CCD 115, etc.

[0056] The Computing and Control Unit 200 has a microprocessor, RAM, ROM, a hard disk drive, a communication interface, etc., just like conventional computers. Storage components, such as a hard disk drive, store computer programs for controlling the ophthalmic observation device 1. The Computing and Control Unit 200 can have various circuit boards, such as circuit boards for OCT image generation. The Computing and Control Unit 200 can have operating components (input components), such as a keyboard, a mouse, and / or a display component, such as an LCD.

[0057] The retinal camera unit 2, the display unit 3, the OCT unit 100 and the computing and control unit 200 can be configured as a single unit (i.e. provided in a single housing) or configured separately in two or more housings. tax system

[0058] Based on Fig. Section 3 describes a configuration of a control system for the ophthalmic observation device 1. steering

[0059] A controller 210 forms the center of the control system of the ophthalmological observation device 1. For example, the controller 210 includes the aforementioned microprocessor, RAM, ROM, hard disk drive, and communication interface, etc. The controller 210 comprises a main controller 211, a memory 212, and a target position reference unit 213. Main control

[0060] The main controller 211 performs various control operations as described above. In particular, the main controller 211 controls focus drives 31A and 43A, an optical system drive 60A, the LED 61, a reflector bar drive 67A, the CCDs 35 and 38, the optical path length changer 41, and the galvo scanner 42 in the retinal camera unit 2. Furthermore, the main controller 211 controls the light source unit 101, the optical attenuator 105, the polarization control 106, and the CCD 115 in the OCT unit 100.

[0061] The focus drive 31A receives control commands from the main controller 211 and moves the focusing lens 31 along the optical axis. This varies the focus position of the optical imaging system 30. The focus drive 31A includes an actuator, e.g., a stepper motor, and a mechanism that transmits the drive force generated by this actuator to the focusing lens 31. The focusing lens 31 is an example of a first focusing lens. The focus drive 31A is an example of a first drive.

[0062] The focus drive 43A receives control commands from the main controller 211 and moves the focusing lens 43 along the optical axis. This varies the focus position of the optical measurement system for OCT. The focus position of the optical measurement system regulates the amount of signal light LS entering the optical fiber 107 via the collimator lens unit 40. The optimal focus position of the optical measurement system is achieved by positioning the focusing lens 43 at a point where the fiber end of the optical fiber 107 on the side of the collimator lens unit 40 and the fundus Ef are optically conjugate. The focus drive 43A includes an actuator, e.g., a stepper motor, and a mechanism that transmits the drive force generated by this actuator to the focusing lens 43.

[0063] The optical system drive 60A receives control commands from the main controller 211 and moves the optical focus system 60 along the optical axis. This varies the aspect of the split target projected onto the fundus Ef. The optical system drive 60A includes an actuator, such as a stepper motor, and a mechanism that transmits the drive force generated by this actuator to the optical focus system 60. For example, the optical focus system 60 is configured as a single unit. The optical focus system 60 projects the split target (focus index) as an indication of a focus state of the optical imaging system 30 onto the fundus Ef and is an example of an optical projection system.

[0064] The reflector actuator 67A receives control commands from the main controller 211 and inserts / removes the reflector 67 from the optical path. The reflector 67 is inserted into the optical path when the split target is projected (i.e., at the beginning of focus adjustment) and removed from the optical path when focus adjustment is complete. The reflector actuator 67A has an actuator, e.g., a magnet, and a mechanism that transmits the driving force generated by this actuator to the reflector 67.

[0065] The main controller 211 controls a drive mechanism (not shown) to move the retinal camera unit 2 in three dimensions. This controller is used for alignment and tracking (following movement). Tracking is a process for moving the optical system in accordance with the eye movement of eye E. When tracking is performed, alignment and focus are pre-set. Tracking is a function to maintain a suitable positional relationship in which alignment and focus are aligned by causing the position of the optical system to follow the eye movement.

[0066] The main controller 211 performs processing to write data into memory 212 and processing to read data from memory 212. memory

[0067] Memory 212 stores various types of data. Data stored in Memory 212 can include, for example, OCT image data, fundus image data, eye information, etc. Eye information includes information about subjects, such as patient IDs and names, and information about eyes, such as left / right eye identification. Memory 212 stores various programs and data for operating the ophthalmic observation device 1.

[0068] Mapping information 212a is pre-stored in memory 212 of this example. Mapping information 212a comprises: first mapping information in which refractive power values ​​(diopters) and positions of the focusing lens 31 are mapped to each other; and second mapping information in which refractive power values ​​(diopters) and positions of the focusing lens 43 are mapped to each other. The first and second mapping information can be separate or combined. Mapping information 212a can be information in which discrete values ​​are mapped to each other, e.g., a table, or information in which continuous values ​​are mapped to each other, e.g., a graph. Target position reference part

[0069] The target position reference part 213 refers target positions of the focusing lens 31 or 43 on the basis of the refractive power of the eye E. The target position reference part 213 is an example of a first target position reference part.

[0070] A target position refers to position information that defines the destination of the focusing lens 31 (or 43). This position information specifies a position on the optical axis of the optical system in which the focusing lens 31 (or 43) is located. The position information can be in any form. For example, it can specify a position on the optical axis itself or the content of control signals for moving the focusing lens 31 (or 43) (e.g., the number of pulse signals transmitted to a stepper motor).

[0071] The refractive power of the eye E is referenced by any refractive power reference unit. For example, if the refractive power of the eye E has been measured in the past, a refractive power reference unit (e.g., the controller 210) can be configured to read the refractive power value recorded in electronic medical records. Alternatively, although a more detailed description will follow, an analyzer 231 in an image processor 230 can obtain the refractive power of the eye E.

[0072] The target position reference element 213 determines the target positions of the first and second focusing lenses 31 and 43 based on the refractive power obtained from the refractive power reference element and the mapping information 212a. Specifically, the target position reference element 213 refers to the first mapping information to determine a position for focusing lens 31 corresponding to the refractive power value obtained from the refractive power reference element and sets it as the target position of focusing lens 31. Similarly, the target position reference element 213 refers to the second mapping information to determine a position for focusing lens 43 corresponding to the refractive power value obtained from the refractive power reference element and sets it as the target position of focusing lens 43. Image generation part

[0073] An image generation unit 220 generates cross-sectional image data of the fundus Ef based on detection signals from the CCD 115. As with conventional spectral-domain OCT, this processing includes noise reduction, filtering, dispersion compensation, FFT (fast Fourier transform), etc. For other types of OCT devices, the image generation unit 220 performs known processing in accordance with the applied type.

[0074] The image generation unit 220 can include the aforementioned circuit boards. "Image data" and "image" based on this image data can be considered identical in this description. Image processor

[0075] An image processor 230 performs various image processing and analysis tasks on images generated by the image generation unit 220. For example, the image processor 220 performs various corrections, such as brightness correction of images. Furthermore, the image processor 230 performs various image processing and analysis tasks on images acquired by the retinal camera unit 2 (fundus images, images of the anterior segment of the eye, etc.).

[0076] The image processor 230 performs a known image processing operation, such as interpolation, which interpolates pixels between cross-sectional images to generate three-dimensional image data of the fundus Ef. Three-dimensional image data refers to image data whose pixel positions are defined by a three-dimensional coordinate system. Three-dimensional image data can be image data composed, for example, of three-dimensionally arranged voxels. Such image data is referred to as volume data, voxel data, etc. To display an image based on volume data, the image processor 230 performs rendering processing (e.g., volume rendering, MIP (maximum intensity projection), etc.) on the volume data to generate image data of a pseudo-three-dimensional image captured from a specific viewing angle. This pseudo-three-dimensional image is displayed on a display 240A.

[0077] It is also possible to generate batch data of cross-sectional images as three-dimensional image data. Batch data is image data obtained by three-dimensionally arranging cross-sectional images captured along scan lines, with the arrangement based on the positional relationship of the scan lines. In other words, batch data is image data obtained by representing cross-sectional images, originally defined in two-dimensional coordinate systems, in a three-dimensional coordinate system (in other words, by embedding them in a three-dimensional space). Analyzer

[0078] The image processor 230 includes the analyzer 231. The analyzer 231 analyzes a front image acquired by photographing the fundus Ef, onto which the split target (focusing index) is projected using the optical infrared photography system, in order to obtain the refractive power of the eye E. For example, this front image is a previously described observation image.

[0079] Fig. Figure 4 illustrates an example of an observation image. The observation image G according to Fig. Figure 4 represents images of a pair of split targets (split target images) B1 and B2 together with the morphology of the fundus Ef. The symbol A denotes a shadow of the reflecting bar 67 (reflecting bar image) positioned in the optical path of the optical illumination system 10. If the focus of the optical imaging system 30 is adequate, i.e., if the focusing lens 31 is in a suitable position, the split target images B1 and B2 are aligned vertically. Fig. 4 arranged. On the other hand, if the focus of the optical imaging system 30 is not adequate, the split target images B1 and B2 are in Fig. 4. Relatively shifted in the horizontal direction. The direction and magnitude of the relative shift between the split target images B1 and B2 correspond to the direction and magnitude of the deviation from a proper focusing state. Such a focus deviation corresponds to the refractive power of the eye E.

[0080] The analyzer 231 stores information (target image / refractive power mapping information) in which directions and magnitudes of the displacement between the split target images B1 and B2, as well as refractive power values, are pre-assigned. The analyzer 231 analyzes an observation image (or one or more freeze frames belonging to the observation image) to obtain displacement information (direction and magnitude of displacement) between the split target images B1 and B2, which are represented in the observation image. Furthermore, the analyzer 231 determines the refractive power corresponding to the obtained displacement information based on the target image / refractive power mapping information. This determined refractive power value is used as the refractive power of the eye E.

[0081] Information about the refractive power of the eye E obtained by the analyzer 231 is sent to the target position reference unit 213. Based on this refractive power information and mapping information 212a, the target position reference unit 213 determines target positions for the focusing lenses 31 and 43. This processing is carried out as before.

[0082] The 230 image processor, which functions as described above, includes, for example, the aforementioned microprocessor, RAM, ROM, hard disk drive, circuit boards, etc. Computer programs that instruct the microprocessor to execute the aforementioned functions are pre-stored in memory components, such as the hard disk drive. User interface

[0083] A user interface 240 comprises a display 240A and a control unit 240B. The display 240A includes a display element in the computing and control unit 200 and / or the display element 3. The control unit 240B includes control elements in the computing and control unit 200. The control unit 240B may include various knobs, buttons, etc., provided on or outside the housing of the ophthalmic observation device 1. For example, if the retinal camera unit 2 has a housing similar to conventional retinal cameras, a joystick, control panel, etc., provided on this housing may be part of the control unit 240B. The display 240A may include various display elements, e.g., a touch-sensitive screen, etc., provided on the housing of the retinal camera unit 2.

[0084] The display 240A and the control unit 240B are not necessarily separate components. For example, as with a touchscreen, a combined component with display and control functions can be used. In this case, the control unit 240B includes the touchscreen and computer programs. Operating commands for the control unit 240 are entered into the controller 210 as electrical signals. Furthermore, operations and / or information input can be performed using a graphical user interface (GUI), which is displayed on the display 240A and the control unit 240B. Signal light scanning and OCT images

[0085] The following section explains scanning with signal light and OCT images.

[0086] Scan modes for the signal light LS through the ophthalmic observation device 1 can include, for example, horizontal, vertical, crossed, radial, circular, concentric, spiral scans, etc. These scan modes are used selectively, taking into account the observation point of the fundus, the analysis mode (retinal thickness, etc.), the time required for scanning, the scan density, etc.

[0087] Horizontal scanning is used for scanning with a signal light (LS) in the horizontal direction (x-direction). Horizontal scanning includes an operating mode for scanning with a signal light (LS) along multiple scan lines that extend horizontally and are arranged vertically (y-direction). In this mode, the interval between scan lines can be set as desired. By setting a sufficiently narrow interval between adjacent scan lines, a three-dimensional image can be generated (three-dimensional scan). Vertical scanning is performed similarly.

[0088] The crossed scan is used for scanning with signal light LS along a cross-shaped path consisting of two straight paths (line paths) that are orthogonal to each other. The radial scan is used for scanning with signal light LS along a radial path consisting of several line paths arranged at predetermined angles. The crossed scan is an example of the radial scan.

[0089] The circular scan is used for scanning with signal light LS along a circular path. The concentric scan is used for scanning with signal light LS along multiple circular paths arranged concentrically around a predetermined center position. The circular scan is an example of the concentric scan. The spiral scan is used for scanning with signal light LS along a spiral path while the radius of rotation gradually decreases (or increases).

[0090] Since the galvo scanner 42 is configured to scan with signal light LS in directions that are orthogonal to each other, it can scan independently in the x and y directions. Scanning along any path on the xy plane is possible with signal light LS by simultaneously controlling the orientations of two galvo mirrors belonging to the galvo scanner 42. As a result, various scanning modes, as described previously, can be implemented.

[0091] Scanning with signal light LS in the previously described operating modes makes it possible to obtain a cross-sectional image in a plane spanned by the direction along a scan line and the fundus depth direction (z-direction). If the interval between scan lines is also narrow, a three-dimensional image can be obtained.

[0092] A region in the fundus Ef that is to be scanned with signal light LS as previously described, i.e., an OCT-treated region in the fundus Ef, is called a scan region. A scan region of a three-dimensional scan is a rectangular region in which several horizontal scans are arranged. A scan region of a concentric scan is a disk-shaped region surrounded by the path of the circular scan with maximum diameter. A scan region of a radial scan is a disk-shaped (or polygonal) region that connects the ends of scan lines. Operational processes

[0093] The following describes the operating procedures of the ophthalmic observation device 1. Fig. Figure 5 shows an example of an operating procedure for the ophthalmological observation device 1. S1: Start recording the observation image

[0094] First, an observational image of the fundus Ef is acquired by continuously illuminating the fundus Ef with observation illumination light. The observational image is a near-infrared moving image that is captured in real time until the continuous illumination is stopped. During this time, the fixation target is projected from the LCD 39 onto the eye E. S2: Perform alignment

[0095] Furthermore, the alignment target from the optical alignment system 50 and the split target from the optical focus system 60 are projected onto eye E. Alignment target images (not shown) and split target images B1 and B2 according to Fig. Four are shown in the observation image. The user or the controller 210 performs the alignment using the alignment targets (manual or automatic alignment). S3: Maintain refractive power

[0096] The analyzer 231 analyzes the observation image (or individual frames thereof) to obtain the refractive power of the eye E. In particular, the analyzer 231 obtains the refractive power of the eye E based on the positions of the split target images B1 and B2, which are represented in the observation image. S4: Obtain target positions of the focusing lenses

[0097] Based on the refractive power of the eye E obtained in step 3 and the assignment information 212a pre-stored in memory 212, the target position reference part 213 refers to a target position (first target position) of the focusing lens 31 in the optical imaging system 30 and a target position (second target position) of the focusing lens 43 in the optical system for OCT (optical measurement system). S5: Move focusing lenses to target positions

[0098] The main controller 211 controls the focus drive 31A so that it moves the focusing lens 31 to the first target position obtained in step 4. Furthermore, the main controller 211 controls the focus drive 43A so that it moves the focusing lens 43 to the second target position obtained in step 4. The main controller 211 can execute these controls in parallel or process them one after the other. The main controller 211 can also detect the current positions of the focusing lenses 31 and 43. For example, one or more position sensors can be provided to detect the positions of the focusing lenses 31 and 43, respectively. Alternatively, a configuration can be used in which the course of controls of the focusing lens 31 or 43 is logged (for example, contents of pulse signals that are transmitted to the focus drive 31A or 43A in the period from a time when the focusing lenses 31 and 43 are at preset initial positions until the present).The main controller 211 sends control signals to move the focusing lens 31 from its current position to the first target position to the focus drive 31A, and sends control signals to move the focusing lens 43 from its current position to the second target position to the focus drive 43A. As a result, the focusing lens 31 is in the first target position, and the focusing lens 43 is in the second target position. S6: Perform OCT of the fundus to acquire a cross-sectional image

[0099] The main controller 211 controls the OCT unit 100, the optical path length change unit 41, the galvo scanner 42, etc., to perform OCT of the fundus Ef. Data acquired by OCT are sent to the image generation unit 220 as detection signals from the CCD 115. The image generation unit 220 generates a cross-sectional image of the fundus Ef based on the detection signals. The main controller 211 displays the generated cross-sectional image on the display 240A. Furthermore, the main controller 211 stores the generated cross-sectional image in memory 212. S7: Perform fundus photography to capture the image

[0100] The main control unit 211 controls the optical illumination system 10 (imaging light source 15, etc.) and the optical imaging system 30 to capture an image of the fundus Ef. The main control unit 211 displays the captured image on the display 240A. Furthermore, the main control unit 211 stores the captured image in memory 212. This concludes this operating example. Effects and impacts

[0101] The following explains the effects of the ophthalmic observation device 1.

[0102] The ophthalmic observation device 1 of this example comprises an optical photography system, an optical measuring system, an optical path coupler, a first and second drive, and a control unit. The optical photography system performs photography to acquire a frontal image of the eye E and includes a first focusing lens. In this example, the optical photography system includes the optical illumination system 10 and the optical imaging system 30, and the focusing lens 31 corresponds to the first focusing lens. The optical measuring system performs OCT to acquire a cross-sectional image of the eye E and includes a second focusing lens. In this example, the optical measuring system includes the optical system housed in the OCT unit 100 and the optical system that forms an optical path from the collimator lens unit 40 to the objective lens 22, and the focusing lens 43 corresponds to the second focusing lens.The optical path coupler couples an optical path of the optical photography system and an optical path of the optical measuring system at a point on the eye-side of the first and second focusing lenses. "Point on the eye-side of the focusing lenses" refers to a location in the optical paths of the respective optical systems on the eye-side of the focusing lenses. In this example, the dichroic mirror 46 corresponds to the optical path coupler. As can be seen from the configuration of the optical path coupler, the first and second focusing lenses are separate optical elements. The first drive moves the first focusing lens along an optical axis of the optical photography system. In this example, the focus drive 31A corresponds to the first drive. The second drive moves the second focusing lens along an optical axis of the optical measuring system. In this example, the focus drive 43A corresponds to the second drive.The controller controls the first and second drives individually. In this example, controller 210 corresponds to the controller.

[0103] According to the ophthalmic observation device 1, the optical photography system and the optical measuring system each have their own individual focusing lenses, and these focusing lenses can be controlled independently. Therefore, the first focusing lens can be positioned at an optimal focus position for capturing front images, and the second focusing lens can be positioned at an optimal focus position for OCT. Consequently, it is possible to perform both front image acquisition and OCT of eye E under suitable focus conditions.

[0104] In this example, the optical photography system performs photography to capture anterior images of the fundus Ef, and the optical measurement system performs OCT to capture cross-sectional images of the fundus Ef. Furthermore, the ophthalmic observation device 1 in this example has a refractive power reference element that references the refractive power of the eye E. Additionally, the controller 210 has a first target position reference element (target position reference element 213) that references target positions of the first and second focusing lenses based on the refractive power referenced by the refractive power reference element. The controller 210 then controls the first drive to move the first focusing lens to the first target position referenced by the first target position reference element and controls the second drive to move the second focusing lens to the second target position.Although this example performs both motion controls of the first and second focusing lenses, it is possible to perform only one of the motion controls. If this is the case, the other motion control can be performed in any way.

[0105] According to such an example, both frontal image acquisition and OCT of the fundus Ef can be performed under suitable focus conditions. Furthermore, movement controls of the focusing lens(es) can be carried out automatically. Since such movement controls can also be performed in accordance with the refractive power of the eye E, the focus can be set with high accuracy.

[0106] The processing to obtain the refractive power of the eye E can be carried out, for example, in the manner described below. As a prerequisite, the optical photography system includes an infrared optical photography system that uses infrared light to photograph the fundus. In this example, the infrared optical photography system includes the optical system that emits observation illumination light from the observation light source 11 onto the fundus Ef, and the optical system that detects the light of the observation illumination reflected from the fundus using the CCD 35. The refractive power reference includes the optical projection system and the analyzer. The optical projection system projects the focusing index onto the fundus Ef as an indication of a focus state of the optical photography system on the fundus Ef. In this example, the optical projection system includes the optical focusing system 60, and the split target corresponds to the focusing index.The analyzer 231 analyzes a front image, which is captured by photographing the fundus Ef using the optical infrared photography system, onto which the focusing index is projected to obtain the refractive power of the eye E.

[0107] Since, according to such an example, the refractive power can be obtained by actually measuring the eye E, it is possible to perform the focus adjustment with high accuracy.

[0108] The processing to obtain one or more target positions of the focusing lens(es) can be carried out, for example, as described below. First, the controller 210 stores mapping information 212a in which refractive power values ​​and positions of the focusing lenses are pre-assigned. The mapping information 212a includes first mapping information, in which refractive power values ​​and positions of the first focusing lens are assigned to each other, and second mapping information, in which refractive power values ​​and positions of the second focusing lens are assigned to each other. The first target position reference element (target position reference element 213) obtains the target positions of the first and second focusing lenses based on the refractive power obtained by the refractive power reference element and the first and second mapping information.In particular, the first target position reference part refers to a target position of the first focusing lens based on the refractive power reference part and the first mapping information, and refers to a target position of the second focusing lens based on the refractive power and the second mapping information.

[0109] According to such an example, focus settings for both optical systems can be made by obtaining target positions for both focusing lenses 31 and 43 based on the refractive power of eye E and the mapping information 212a. Consequently, it is possible to perform both frontal image acquisition and OCT of eye E with suitable focus conditions. Second example

[0110] This example illustrates an ophthalmic observation device configured to perform frontal image acquisition using the results of OCT focusing. For instance, when examining the fundus of an eye, taking into account miosis (pupil constriction), visible light photography is usually performed after OCT. This example is effective for examinations performed in such a sequence. Configurations

[0111] An ophthalmological observation device of this example has an overall configuration and optical systems similar to the first example. The control system is also nearly identical to that of the first example. In the following explanation, the same reference symbols are used for components similar to those in the first example.

[0112] Fig. Figure 6 illustrates a configuration example for a control system of the ophthalmic observation device. In this example, a target position reference part 214 is used instead of the target position reference part 213 of the first example. Furthermore, the mapping information 212a is not necessarily stored in memory 212, and / or the analyzer 231 is not necessarily included in the image processor 230. These differences are described in detail below.

[0113] Based on the position of the focusing lens 43 in the optical measuring system during OCT, the target position reference part 214 refers to a target position of the focusing lens 31 in the optical imaging system 30. The target position reference part 214 is an example of a second target position reference part.

[0114] An example of the processing performed by the target position reference part 214 is explained. Before OCT is performed, the focus is set for the OCT scan. This focus can be set using an infrared fundus image (observation image) and a split target, as in the first example; however, fine-tuning can also be performed using OCT images. For example, by repeatedly performing OCT on essentially the same cross-section of the fundus Ef, a moving image of this cross-section (OCT moving image) can be acquired. The frame rate of the OCT moving image corresponds to the repetition rate of the OCT scan.

[0115] By displaying the OCT moving image on the 240A display, the user can manually adjust the focus.

[0116] A known technique involves automatic focus adjustment by analyzing the OCT motion image (or its associated still images) using the ophthalmic viewing device. This analysis includes: analyzing pixel values ​​(brightness values) of one or more still images belonging to the OCT motion image to specify one or more high-quality image regions; and specifying the current focus position based on the position (z-coordinate) of the high-quality image region in the depth direction (z-direction) of the still image. Furthermore, if one or more tissues (retinal surface, retinal pigment epithelium, choroid, etc.) of the fundus (Ef) to be focused on have been previously identified, the image processor 230 specifies a region corresponding to the respective tissue (target region) in the still image. Alternatively, the user can mark a target region.The image processor 230 determines the position (z-coordinate) of the target region in the depth direction (z-direction) of the single image. The main control unit 211 generates a control signal to change the current focus position of the optical measuring system to a focus position corresponding to the target region and transmits the control signal to the focus drive 43A. Thus, the focusing lens 43 is positioned at the position corresponding to the target region.

[0117] Here, the positions in the depth direction (z-direction) of the individual images and the positions of the focusing lens 43 in the optical measuring system can be pre-assigned to each other based on the configuration of the optical measuring system. It is also possible to provide a function for correcting this assignment by taking into account the refractive power of the eye E, etc.

[0118] The fundus Ef, displayed as an OCT moving image, moves within the individual frames as a result of eye movements and pulse movements; however, techniques exist for fixing the image of the fundus Ef at a predetermined position within the individual frames by controlling the optical path length change unit 41 to follow the movement of this image. Methods for focus adjustment using OCT images are not limited to the above examples, and any method can be applied.

[0119] Based on the position of the focusing lens 43, which was determined by focus adjustment using OCT images as previously described, the target position reference part 214 detects a target position of the focusing lens 31 in the optical imaging system 30.

[0120] Examples of this processing are described. Information mapping the positions of focusing lens 31 to the positions of focusing lens 43 can be pre-stored in memory 212, and a position of focusing lens 31 corresponding to the position of focusing lens 43 applied during OCT can be obtained by referencing the stored information. This information can be generated, for example, using the refractive power value of the eye, as described in the first example. Alternatively, this information can be generated by referring to configurations of the optical photography system and optical measurement system, the difference between the wavelengths of the light used for fundus photography and the wavelengths of the light used for OCT. If the refractive power of the eye E is known, this information can be generated or corrected based on the value of this refractive power.The foregoing examples are not limited to processing to obtain a position of the focusing lens 31 from the position of the focusing lens 43 during OCT, and the target position reference part 214 can perform this processing in any way.

[0121] The main control 211 controls the focus drive 31A to move the focusing lens 31 into the target position referenced by the target position reference part 214. Operational processes

[0122] The following describes the operating procedures of the ophthalmic observation device in this example. Fig. Figure 7 shows an example of the operation of the ophthalmic observation device. S11: Start recording the observation image

[0123] As in the first example, the acquisition of the observation image is started, and the fixation of eye E is performed. S12: Perform alignment and focusing

[0124] As in the first example, the alignment target and the split target are projected onto eye E. Alignment is then performed using the alignment target, and focus is set using the split target. Focus is set for both the optical photography system and the optical measuring system. S13: Start OCT

[0125] The main controller 211 controls the OCT unit 100, the optical path length changer 41, the galvo scanner 42, etc., to initiate OCT of the fundus Ef. This OCT is essentially performed repeatedly on the same cross-section of the fundus Ef. In other words, this OCT is performed in an operating mode for capturing OCT moving images. S14: Perform focus adjustment using the OCT moving image

[0126] The user or the ophthalmic observation device performs the fine focus adjustment using an OCT moving image. S15: Capture a cross-sectional image of the fundus

[0127] Once the fine focus adjustment in step 14 is complete, or if the user performs a predetermined operation, the main controller 211 controls the OCT unit 100, the optical path length changer 41, the galvo scanner 42, etc., to perform OCT of the fundus Ef. This OCT is performed in a predefined operating mode. Consequently, one or more cross-sectional images are acquired for use in diagnosis. S16: Reference target position of the focusing lens of the optical photography system

[0128] Once OCT is complete or the user performs a predetermined operation, the target position reference part 214 obtains a target position of the focusing lens 31 in the optical photography system based on the position of the focusing lens 43 applied to OCT in step 15, i.e., based on the position of the focusing lens 43 achieved by the focus adjustment in step 14. S17: Move the focus lens of the optical photography system into the target position

[0129] The main control 211 controls the focus drive 31A to move the focusing lens 31 to the target position obtained in step 16. S18: Perform fundus photography to obtain the captured image

[0130] The main control unit 211 controls the optical illumination system 10 (imaging light source 15, etc.) and the optical imaging system 30 to capture an image of the fundus Ef. The main control unit 211 displays the captured image on the display 240A. Furthermore, the main control unit 211 stores the captured image in memory 212. This concludes this operating example. Effects and impacts

[0131] The following section explains the effects and properties of the ophthalmic observation device in this example.

[0132] The ophthalmological observation device of this example comprises an optical photography system, an optical measuring system, an optical path coupler, a first and second drive, and a control unit. Consequently, the optical photography system and the optical measuring system each have their own individual focusing lenses, and these focusing lenses can be controlled independently. Therefore, the first focusing lens can be positioned at an optimal focus position for capturing frontal images, and the second focusing lens can be positioned at an optimal focus position for OCT. As a result, it is possible to perform both frontal image acquisition and OCT of eye E under suitable focus conditions.

[0133] In this example, the controller (210) includes the target position reference element 214 (second target position reference element), which establishes a target position for the focusing lens 31 in the optical photography system based on the position of the focusing lens 43 of the optical measuring system during OCT. Furthermore, the controller operates the focus drive 31A to move the focusing lens 31 to the target position established by the target position reference element 214.

[0134] The example configured in this way can capture frontal images of eye E with good focus conditions, since the focus of the optical photography system can be adjusted with high precision and accuracy by referencing the focus result obtained using OCT images. Furthermore, there is a risk that the optical photography system may become defocused during OCT due to eye movement, etc. In such situations, the example can perform frontal image capture photography with suitable focus conditions, as the focus of the optical photography system can be adjusted based on the focus conditions obtained during OCT. Moreover, the example is not inconvenient for the user, as the focus of the optical photography system can be adjusted automatically after the OCT.

[0135] The processing for obtaining the target position of the focusing lens 31 in the optical photography system can be based on OCT moving images. In this example, the optical measurement system repeatedly performs OCT on essentially the same cross-section of the eye, thereby capturing an OCT moving image of this cross-section. Furthermore, the target position reference part 214 can obtain a target position of the focusing lens 31 in the optical photography system based on the position of the focusing lens 43, which was determined based on the multiple cross-sectional images (i.e., individual frames of the OCT moving image) acquired by the repeated OCT.

[0136] When an OCT moving image is used in this way, the image corresponding to the fundus Ef can be fixed at a predetermined position in the individual images as described previously. Therefore, a target position of the focusing lens 31 in the optical photography system can be maintained with high accuracy even if eye movement, pulse rate, etc. occur during the OCT. Third example

[0137] This example explains user interfaces for performing focus adjustment of the optical photography system and optical measurement system based on OCT images. Configurations

[0138] An ophthalmic observation device of this example has an overall configuration and optical systems similar to the first example. The control system is also nearly identical to that of the first example. In the following explanation, the same reference symbols are used for components similar to those in the first example.

[0139] Fig. Figure 8 illustrates a configuration example for a control system of the ophthalmic observation device. In this example, a target position reference part 215 is used instead of the target position reference part 213 from the first example. Furthermore, the mapping information 212a is not necessarily stored in memory 212, and / or the analyzer 231 is not necessarily included in the image processor 230. Additionally, the image processor 230 has a layer region specification part 232. These differences are described in detail below.

[0140] The main control unit 211 displays cross-sectional images of the fundus Ef, captured by OCT, on the display 240A. The user uses the operating unit 240B to mark a desired position within the cross-sectional image displayed on the 240A. The desired position is the point (target focus position) within the cross-section on which the user wishes to focus.

[0141] The focus target position can be a focus target position for the optical measuring system and / or a focus target position for the optical photography system. A user interface capable of identifying both focus target positions can be provided, or a user interface capable of identifying only one of them.

[0142] The focus target positions of the two optical systems can be the same or different. In the former case, a user interface is provided that can label both focus target positions individually or simultaneously. In the latter case, a user interface is provided that can label both focus target positions individually. If the relationship between the two focus target positions is pre-defined based on refractive power, wavelength, etc., a configuration can be used in which one of the focus target positions is automatically labeled based on the labeling result of the other. Specific configurations of the user interfaces listed here as examples are arbitrary.

[0143] The target position reference element 215 acquires a target position of the focusing lens 31 (first target position) and / or a target position of the focusing lens 43 (second target position) based on a position marked in a cross-sectional image using the control element 240. The target position reference element 215 is an example of a third target position reference element. Any processing is performed by the target position reference element 215 to acquire these target positions. Examples of user interface configurations and processing performed by the target position reference element 215 are explained below. First processing example

[0144] Based on Fig. Section 9 describes a first processing example. In this processing example, an OCT motion image is frozen (i.e., switched to still image display), and a focus position is marked. S21: Display OCT moving image

[0145] The main controller 211 controls the OCT unit 100, the optical path length changer 41, the galvo scanner 42, etc., to perform repeated OCT scans on essentially the same cross-section of the eye (fundus Ef). Based on several cross-sectional images acquired by this repeated OCT scan, the main controller 211 displays a moving image on the display 240A in real time. S22: Switch to freeze frame display

[0146] In response to a predetermined operation (operation to indicate still image display) performed using the control unit 240B, the main control 211 switches operating modes for displaying cross-sectional images from moving image display to still image display.

[0147] A still image and a moving image can be displayed side by side. For example, a display region for showing a still image (still image display region) is provided on a display screen in addition to a display region for a real-time OCT moving image. Furthermore, in response to the marking of a still image display, while maintaining the OCT moving image display, it is possible to display a single frame (still image) of the OCT moving image on the still image display region corresponding to the time at which the marking occurs. If the marking is performed multiple times, the still images displayed on the still image display region can be updated with each marking. Alternatively, it is possible to display the still images received with each marking side by side. Multiple still images can be displayed at the same size, and some of the still images can be reduced in size (in thumbnail view, etc.).) will be displayed, or the display of part of the still images can be stopped. S23: Mark position in cross-sectional image

[0148] The user operates the 240B control unit to mark a desired position in the cross-sectional image, which is displayed as a still image. The marked position is, for example, a location indicating a specific tissue of the fundus Ef, which is shown in the cross-sectional image.

[0149] The number of labeled positions is unlimited. For example, positions can be individually labeled to indicate areas (retinal surface, etc.) to be examined more closely with a single image, as well as positions to indicate areas (retinal pigment epithelium, choroid, etc.) to be examined more closely with a cross-sectional image. When labeling two or more positions, information can be entered to distinguish between them. For example, information can be entered to indicate that the first labeled position is for fundus photography, and information can be entered to indicate that the second labeled position is for OCT.

[0150] When a single position is marked, the marked position is treated as being for a predetermined purpose (for OCT or fundus photography).

[0151] Information indicating one or more marked positions can be displayed along with one or more cross-sectional images. For example, an image indicating a marked position can be displayed over a cross-sectional image. If the device has the aforementioned function that the OCT moving image follows eye movement, pulse rate, etc., it is also possible to change the information indicating the marked position chronologically so that it follows the eye movement, etc. An image indicating the marked position can also be changed chronologically in response to switching the display mode of the cross-sectional image to video display. S24: Target position of the focusing lens maintained

[0152] Based on the position marked in step 23 in the cross-sectional image, the target position reference part 215 refers to a target position of the focusing lens 31 (first target position) and / or a target position of the focusing lens 43 (second target position).

[0153] The processing to determine the first target position is based, for example, on a coordinate (z-coordinate) of the first target position in the depth direction (z-direction) in a single frame of the cross-sectional image. The processing to determine the second target position is based, for example, on a coordinate (z-coordinate) of the second target position in the depth direction (z-direction) in a single frame of the cross-sectional image. It is assumed that the z-coordinates in the single frames and the positions of the focusing lens 31 and / or the focusing lens 43 are pre-assigned to each other. The target position(s) can be corrected based on the refractive power of the eye, etc. S25: Move focusing lens to target position

[0154] Once the first target position is obtained in step 24, the main control unit 211 controls the focus drive 31A to move the focusing lens 31 to the first target position. Once the second target position is obtained in step 24, the main control unit 211 controls the focus drive 43A to move the focusing lens 43 to the second target position. S26: Perform OCT to acquire a cross-sectional image

[0155] The main controller 211 controls the OCT unit 100, the optical path length change unit 41, the galvo scanner 42, etc., to perform OCT of the fundus Ef. The image generation unit 220 generates a cross-sectional image of the fundus Ef based on detection signals from the CCD 115. The main controller 211 displays the generated cross-sectional image on the display 240A. Furthermore, the main controller 211 stores the generated cross-sectional image in memory 212. S27: Perform fundus photography to capture the image

[0156] The main control unit 211 controls the optical illumination system 10 (imaging light source 15, etc.) and the optical imaging system 30 to capture an image of the fundus Ef. The main control unit 211 displays the captured image on the display 240A. Furthermore, the main control unit 211 stores the captured image in memory 212. This concludes this operating example. Second processing example

[0157] Based on Fig. Section 10 describes a second processing example. In this processing example, a focus position is marked by moving a position marker image, displayed on an OCT motion image, to a desired position. S31: Display OCT moving image

[0158] The main controller 211 controls the OCT unit 100, the optical path length changer 41, the galvo scanner 42, etc., to perform repeated OCT scans on essentially the same cross-section of the eye E (fundus Ef). Based on several cross-sectional images acquired by this repeated OCT scan, the main controller 211 displays a real-time OCT motion image on the display 240A. S32: Show image for position identification

[0159] The main control 211 displays an image for position marking at a point in the OCT moving image corresponding to the focus position (i.e., position of the focusing lens 43) during the repeated OCT in step 31.

[0160] If z-coordinates in the (single frame of the) OCT moving image(s) and positions of the focusing lens 43 are pre-assigned, the main control 211 obtains a position (z-coordinate) in the OCT moving image corresponding to the position of the focusing lens 43 during the OCT and displays the image for position marking over the obtained position. The display position of the image for position marking can be corrected based on the refractive power of the eye E, etc.

[0161] The position marker image can be a linear image that passes the specified position (z-coordinate) and is orthogonal to the depth direction (z-direction). Alternatively, the position marker image can be a linear or arrow-shaped image displayed at a location outside the OCT motion image corresponding to the specified position (z-coordinate). Generally, the position marker image is displayed above or near the OCT motion image and serves to indicate the focus position within the OCT motion image.

[0162] If the device has the aforementioned function that the OCT moving image follows the eye movement, pulse, etc., it is possible to change the display position of the image for position marking chronologically so that it follows the eye movement, etc.

[0163] The number of images displayed for position identification is arbitrary. For example, a first image could be displayed to mark areas (retinal surface, etc.) that are to be observed more closely with a scan image, and a second image could be displayed to mark areas (retinal pigment epithelium, choroid, etc.) that are to be observed more closely with a cross-sectional image. When two or more images are displayed for position identification, the respective images can be distinguished. For example, display aspects (display colors, etc.) of the first and second images for position identification can differ.

[0164] When a single image is displayed for position identification, the image is used for position identification for a predetermined purpose (for OCT or fundus photography). S33: Move image to desired position for position marking.

[0165] The user operates the 240B control unit to move the image for position marking to a desired position. The desired position indicates, for example, a specific tissue of the fundus Ef, which is shown in the cross-sectional image. S34: Maintain the target position of the focusing lens

[0166] Based on the position of the image for position marking after movement in step 33, the target position reference part 215 refers to a target position of the focusing lens 31 (first target position) and / or a target position of the focusing lens 43 (second target position).

[0167] The processing to determine the first target position is based, for example, on a coordinate (z-coordinate) from the image used to identify the position in the depth direction (z-direction) within a single frame of the cross-sectional image. The processing to determine the second target position is also based, for example, on a coordinate (z-coordinate) from the image used to identify the position in the depth direction (z-direction) within a single frame of the cross-sectional image. It is assumed that the z-coordinates in the single frames and the positions of the focusing lens 31 and / or the focusing lens 43 are pre-assigned to each other. The target position(s) can be corrected based on the refractive power of the eye, etc. S35: Move focusing lens to target position

[0168] Once the first target position is obtained in step 34, the main control unit 211 controls the focus drive 31A to move the focusing lens 31 to the first target position. Once the second target position is obtained in step 34, the main control unit 211 controls the focus drive 43A to move the focusing lens 43 to the second target position. S36: Perform OCT to acquire a cross-sectional image

[0169] The main controller 211 controls the OCT unit 100, the optical path length change unit 41, the galvo scanner 42, etc., to perform OCT of the fundus Ef. The image generation unit 220 generates a cross-sectional image of the fundus Ef based on detection signals from the CCD 115. The main controller 211 displays the generated cross-sectional image on the display 240A. Furthermore, the main controller 211 stores the generated cross-sectional image in memory 212. S37: Perform fundus photography to capture the image

[0170] The main control unit 211 controls the optical illumination system 10 (imaging light source 15, etc.) and the optical imaging system 30 to capture an image of the fundus Ef. The main control unit 211 displays the captured image on the display 240A. Furthermore, the main control unit 211 stores the captured image in memory 212. This concludes this operating example. Other processing examples

[0171] In the first and second processing examples described above, the following processing can be performed. The layer region specification part 232 analyzes a cross-sectional image (a still image belonging to an OCT motion image) displayed on the display 240A to specify a layer region in this cross-sectional image that corresponds to a predetermined layer. The layer region is an image region corresponding to at least one of the layered tissues of the fundus ef that has a layered structure. In particular, the layered tissues of the fundus ef include the inner limiting membrane, the nerve fiber layer, the ganglion cell layer, the inner plexiform layer, the inner granular layer, the outer plexiform layer, the outer granular layer, the outer limiting membrane, the stratum neuroepitheliale, the retinal pigment epithelium, the choroid, the sclera, etc.

[0172] The main control unit 211 displays an image (slice image) indicating the slice region specified by the slice region specification part 232 over the cross-sectional image. If the device has the aforementioned function that the OCT moving image follows eye movement, pulse rate, etc., the main control unit 211 can chronologically change the display position of the image for position marking so that it follows the eye movement, etc. Effects and impacts

[0173] The following section explains the effects of the ophthalmic observation device used in this example.

[0174] The ophthalmological observation device of this example comprises an optical photography system, an optical measuring system, an optical path coupler, a first and second drive, and a control unit. Consequently, the optical photography system and the optical measuring system each have their own individual focusing lenses, and these focusing lenses can be controlled independently. Therefore, the first focusing lens can be positioned at an optimal focus position for capturing frontal images, and the second focusing lens can be positioned at an optimal focus position for OCT. As a result, it is possible to perform both frontal image acquisition and OCT of eye E under suitable focus conditions.

[0175] The ophthalmic observation device of this example comprises the display (240A) and the control unit (240B). The display shows a cross-sectional image acquired by OCT. The control unit is used to mark a position in the cross-sectional image, which is indicated by the display. Furthermore, the controller (210) of this example has a third target position reference element (target position reference element 215). The third target position reference element establishes a target position for the first focusing lens (focusing lens 31) and / or a target position for the second focusing lens (focusing lens 43) based on the position marked by the control unit. Subsequently, the controller operates the first drive (focusing drive 31A) and / or the second drive (focusing drive 43A) to move the first focusing lens and / or the second focusing lens to the target position established by the third target position reference element.

[0176] If the optical measurement system (OCT) performs repeated scans on essentially the same cross-section of the eye, the display can show several OCT-captured cross-sectional images as a video. Furthermore, the control unit switches the video display to a still image display in response to a predetermined operation performed using the control unit. Then, based on a position marked on a still image displayed using the control unit, the third target position reference can reference the target position(s) of the first and / or second focusing lens.

[0177] If the optical coherence tomography (OCT) system performs repeated measurements on essentially the same cross-section of the eye and a film is displayed, the following procedure can be used. The display shows a position-marking image that is movable relative to the film according to a predetermined operation performed using the control unit. Based on a position marked by the operation for the position-marking image, the third target position reference can reference the target position(s) of the first and / or second focusing lens.

[0178] The control unit can display an image as a position indicator, specifying a position on the film that corresponds to the position of the second focusing lens during repeated OCT.

[0179] According to such an example, one or more desired focus positions for a cross-sectional image can be marked, and one or more focus positions for eye photography and / or OCT can be automatically set for the specified position(s). embodiment

[0180] To optimize the focus position for OCT in actual examinations, it is desirable to consider not only the differences between light wavelengths used for photography (e.g., visible wavelengths) and those used for OCT (e.g., near-infrared wavelengths), but also individual differences in the optical properties of the eyes. This embodiment takes the optical properties of the eyes into account to perform focus adjustment for OCT. Such focus adjustment has two steps: coarse adjustment and fine adjustment. The coarse adjustment is performed using a split target (focus index) or a measurement of the eye's refractive power. The fine adjustment is performed based on the interference sensitivity of the OCT. Configurations

[0181] An ophthalmological observation device of this embodiment has an overall configuration and optical systems similar to the first example. The control system is also nearly identical to that in the first example. In the following explanation, the same reference numerals are used for components similar to those in the first example.

[0182] Fig. Figure 11 illustrates a configuration example for a control system of the ophthalmic observation device of this embodiment. The control unit 210 has a target position reference element 216. The image generation unit 220 has an interference intensity reference element 221.

[0183] The interference intensity reference 221 references the intensity of an interference signal (interference intensity) detected by the optical measurement system performing OCT. An interference signal is a detection signal output by the CCD 115 or a signal obtained by processing the detection signal. Examples of such signal processing include any signal processing used in spectral-domain OCT or swept-source OCT. For example, the interference intensity reference 221 detects the amplitude of an interference signal to obtain the interference intensity. The interference intensity reference 221 is an example of an "intensity reference."

[0184] In this embodiment, multiple interference signals are acquired while the position of the focusing lens 43 in the optical measuring system is changed. The interference intensity reference element 221 acquires the intensities of the respective interference signals. For example, multiple interference signals are acquired in the manner shown below.

[0185] The main controller 211 controls the focus drive 43A to move the focusing lens 43. This movement can be continuous or discrete (stepwise). In the former case, the main controller 211 controls the optical measurement system (light source unit 101, etc.) to perform OCT multiple times while the focusing lens 43 is moved continuously. In the latter case, the main controller 211 moves the focusing lens 43 sequentially to a first to nth position and controls the optical measurement system to perform OCT in the state in which the focusing lens 43 is located at the respective positions. By performing such control, multiple interference signals are obtained corresponding to multiple positions of the focusing lens 43.

[0186] With this control system, the range of motion of the focusing lens 43 can be predefined. Specifically, multiple interference signals are acquired by repeatedly performing OCT while the focusing lens 43 is moved within a predefined range. The range of motion of the focusing lens 43 includes a position that is predetermined by the coarse adjustment (focus adjustment based on the split target) described later. For example, the center of the focusing lens 43's range of motion is set to be at the position determined by the coarse adjustment (reference position). The range of motion of the focusing lens 43 can also be defined based on the refractive power variation along the optical axis of the optical measurement system. As a specific example, the range of motion of the focusing lens 43 is set to a range of ±3 diopters with its center at the reference position.

[0187] Based on the multiple interference intensities referenced by the interference intensity reference element 221, the target position reference element 216 references a target position of the focusing lens 43. The target position reference element 216 is an example of a “fourth target position reference element”.

[0188] The following is an example of the processing performed by the target position reference part 216. The target position reference part 216 specifies the maximum intensity among the multiple interference intensities referenced by the interference intensity reference part 221. This processing is performed by comparing values ​​of the interference intensities. Furthermore, the target position reference part 216 defines a position of the focusing lens 43 corresponding to the specified maximum intensity as the target position. This processing is performed, for example, by specifying a position when an interference signal with maximum intensity is detected, among multiple positions of the focusing lens 43 applied to the previously described multiple OCTs; and defining the specified position as the target position.

[0189] The processing performed by the target position reference element 216 is not limited to this. For example, based on the multiple interference intensities obtained, the target position reference element 216 relates a variation in the interference intensity to the movement of the focusing lens 43. This processing includes, for example, determining a curve (continuous values) that continuously connects the interference intensities (discrete values). This curve can be defined in a coordinate system in which, for example, a horizontal axis indicates the positions of the focusing lens 43 and a vertical axis indicates interference intensities. Furthermore, the target position reference element 216 determines a peak value of the interference intensity based on the obtained variation in the interference intensity. The target position reference element 216 then assigns a position to the focusing lens 43 corresponding to the determined peak value.The obtained position can be any of the multiple positions of the focusing lens 43 in the application to the multiple OCTs, or it can differ from them. Operational processes

[0190] The following describes the operating procedures of the ophthalmic observation device of this embodiment. Fig. Figure 12 shows an example of the operation of the ophthalmic observation device. S41: Start recording the observation image

[0191] As in the first example, the acquisition of the observation image is started, and the fixation of eye E is performed. S42: Perform alignment

[0192] As in the first embodiment, the alignment target and the split target are projected onto eye E. The alignment is then performed using the alignment target. S43: Perform coarse focus adjustment

[0193] Focus adjustment is performed using the split target (coarse adjustment). Coarse adjustment can be done manually or automatically (autofocus). The focus adjustment using the split target has been described above.

[0194] In this stage, the focus adjustment is performed for both the optical imaging system 30 and the optical measuring system. For example, the position of the focusing lens 31 in the optical imaging system 30 is determined using the split target, as with general retinal cameras, and the focusing lens 43 is moved to a position corresponding to the determined position. The relationship between the positions of the focusing lens 31 and the positions of the focusing lens 43 is predefined, and information about this relationship is stored in memory 212. S44: Detecting interference signals with different focus states

[0195] The main controller 211 detects several interference signals while changing the position of the focusing lens 43 in the optical measuring system. This processing is carried out in the manner described above. S45: Obtain interference intensity

[0196] The interference intensity reference part 221 references the interference intensity of each of the multiple interference signals acquired in step 44. S46: Maintain the target position of the focusing lens

[0197] Based on the multiple interference intensities obtained in step 45, the target position reference part 216 determines a target position of the focusing lens 43. S47: Move focusing lens to target position

[0198] The main control 211 controls the focus drive 43A to move the focusing lens 43 to the target position obtained in step 46. S48: Perform OCT to acquire a cross-sectional image

[0199] The main controller 211 controls the OCT unit 100, the optical path length changer 41, the galvo scanner 42, etc., to perform OCT of the fundus Ef. The image generation unit 220 generates a cross-sectional image of the fundus Ef based on detection signals from the CCD 115. The main controller 211 displays the generated cross-sectional image on the display 240A. Furthermore, the main controller 211 stores the generated cross-sectional image in memory 212. OCT is performed in a focus state that is finely adjusted based on the interference intensity. Therefore, high-sensitivity OCT can be achieved. S49: Perform fundus photography to obtain the captured image

[0200] The main control unit 211 controls the optical illumination system 10 (image light source 15, etc.) and the optical imaging system 30 to capture a photographic image of the fundus Ef. The main control unit 211 displays the captured photographic image on the display 240A. Furthermore, the main control unit 211 stores the captured photographic image in memory 212. This concludes this operating example. Here, this fundus photography is performed in a suitable focus state, which was achieved by setting the focus using the split target in step 43. This concludes this operating example. Effects and impacts

[0201] The following section explains the effects and properties of the ophthalmic observation device of this embodiment.

[0202] The ophthalmological observation device of this embodiment comprises an optical photography system, an optical measuring system, an optical path coupler, a first and second drive, and a control unit. Consequently, the optical photography system and the optical measuring system each have their own individual focusing lenses, and these focusing lenses can be controlled independently. Therefore, the first focusing lens can be positioned at an optimal focus position for capturing frontal images, and the second focusing lens can be positioned at an optimal focus position for OCT. As a result, it is possible to perform both frontal image acquisition and OCT of eye E under suitable focus conditions.

[0203] In this embodiment, the optical measurement system (OCT) is used to acquire a cross-sectional image of the fundus Ef. Furthermore, the ophthalmic observation device of this embodiment includes the optical focusing system 60 (optical projection system) and the interference intensity reference element 221 (intensity reference element). The optical projection system projects the split target (focus index) onto the fundus Ef as an indication of the focus state of the optical imaging system 30 on the fundus Ef. The interference intensity reference element 221 references the intensity of an interference signal acquired by the optical measurement system. After focusing of the optical imaging system 30 and focusing of the optical measurement system based on the focus index (i.e.,(after coarse adjustment), the main control 211 further controls the focus drive 43A on the basis of the interference intensity referenced by the interference intensity reference part 221 in order to fine-tune the focus condition of the optical measuring system.

[0204] In this embodiment, the controller 210 can perform the following processing. The main controller 211 controls the optical measuring system while simultaneously controlling the focus drive 43A to move the focusing lens 43 so that multiple interference signals corresponding to multiple positions of the focusing lens 43 are acquired. Next, the target position reference 216 obtains a target position of the focusing lens 43 based on multiple interference intensities obtained by the interference intensity reference 221. The main controller 211 then controls the focus drive 43A to move the focusing lens 43 to the obtained target position.

[0205] The target position reference part 216 specifies the maximum intensity among the multiple interference intensities referenced by the interference intensity reference part 221 and adopts a position of the focusing lens 43 corresponding to the specified maximum intensity as the target position.

[0206] The main control 211 moves the focusing lens 43 within a predetermined range to detect the multiple interference signals, thereby streamlining the fine adjustment. This predetermined range can include the position of the focusing lens 43 determined by the coarse adjustment. In particular, the center of the predetermined range can be located at the position of the focusing lens 43 determined by the coarse adjustment.

[0207] Coarse adjustment is performed manually or automatically. In the automatic case, the ophthalmic observation device of this embodiment can be configured as shown below. The optical imaging system 30 comprises an optical infrared photography system that uses infrared light for photography to capture a frontal image of the fundus Ef. The optical infrared photography system can be the optical system that illuminates the eye E with observation illumination light and detects its reflected light as described in the first embodiment.The main control 211 focuses the optical imaging system 30 by moving the focusing lens 31 and the optical focus system 60 on the basis of the front image of the fundus Ef, onto which the split target is projected, captured by photographing with the aid of the optical infrared photography system, and performs the focusing of the optical measuring system (i.e. the movement of the focusing lens 43) on the basis of the result of this focusing.

[0208] Such an embodiment can perform OCT with high sensitivity because the focus conditions of the optical measurement system can be adjusted based on the interference intensity. For example, with a suitable focus condition, OCT can be performed even if proper coarse focusing cannot be achieved due to vignetting of the split target by an iris. Furthermore, fine focusing can begin undisturbed because coarse focusing occurs before fine focusing. Examples of variations

[0209] The following are examples of variations of this embodiment.

[0210] The coarse adjustment can be made using a previously obtained measurement of the refractive power of the eye E instead of the split target. A configuration of this modified example can be the same as the fourth embodiment (see Fig. 11) unless otherwise stated.

[0211] Memory 212 stores a previously obtained measurement of the refractive power of the eye E. This measurement can be obtained from another ophthalmological device (automatic refractometer, etc.) or from this ophthalmological observation device. In the former case, the main controller 211 stores a measurement input into this ophthalmological observation device in memory 212. In the latter case, this ophthalmological observation device is equipped with a refractive power reference element that obtains the refractive power of an eye under examination. The refractive power reference element has, for example, configurations as described in the first embodiment. The main controller 211 stores a measurement obtained from the refractive power reference element in memory 212.

[0212] The interference intensity reference element 221 acquires the intensity of the interference signal detected by the optical measuring system as in the aforementioned embodiment. For coarse focus adjustment, the main control 211 performs focus adjustments of the optical imaging system 30 and the optical measuring system based on the measured value stored in memory 212. For example, the focus adjustment is based on the refractive power of the eye as in the first embodiment. Furthermore, the main control 211 controls the focus drive 43A based on the interference intensity acquired by the interference intensity reference element 221 in order to perform fine adjustment of the focus condition of the optical measuring system.

[0213] This modified example allows for high-sensitivity OCT because the focus conditions of the optical measurement system can be adjusted based on the interference intensity. Furthermore, the fine-tuning can begin undisturbed, as the coarse adjustment precedes the fine-tuning. Even if an ophthalmic observation device lacks a function for projecting a focusing index, such as a split target, or if such a function is impaired, the coarse adjustment of focus conditions can still be performed. Examples of variations

[0214] The configurations described above merely illustrate one advantageous implementation of the invention. Therefore, any modifications (omission, substitution, addition) within the scope of protection of the invention are permissible. Furthermore, various configurations described in the preceding embodiments can be combined in any way.

[0215] In the aforementioned embodiments, the optical path length difference between the optical paths of the signal light LS and the reference light LR is changed by varying the position of the optical path length changer 41; however, methods for changing the optical path length difference are not limited to this. For example, the optical path length difference can be changed by placing a reflective mirror (reference mirror) in the optical path of the reference light and moving the reference mirror in the forward direction of movement of the reference light to change the optical path length of the reference light. Furthermore, the optical path length difference can be changed by moving the retinal camera unit 2 and / or the OCT unit 100 relative to the eye E to change the optical path length of the signal light LS. If an object is not a part of a living body or similar, the optical path length difference can be changed by moving the object in the depth direction (z-direction).

[0216] Computer programs for implementing the aforementioned embodiments can be stored on all types of computer-readable recording media. Examples of such recording media include optical discs, semiconductor memory, magneto-optical discs (CD-ROM, DVD-RAM, DVD-ROM, MO, etc.), magnetic storage media (hard drives, floppy disks (TM), ZIP, etc.), and so on.

[0217] The programs can be transmitted via networks, e.g., Internet, LAN, etc. Explanation of reference symbols 1 ophthalmological observation device 2 Retinal camera unit 10 optical lighting system 30 optical imaging system 31 Focusing lens 31A Focus Drive 41 optical path length change part 42 Galvo scanners 43 Focusing lens 43A Focus Drive 60 optical focusing system 60A optical system drive 100 OCT units 200 computing and control units 210 Control 211 Main control 212 storage 212a Allocation information 213, 214, 215, 216 Target position reference part 220 Image generation part 221 Interference intensity reference part 230 image processor 231 Analyzer 232 Layer Region Specification Part 240A display 240B Control Unit E eye Ef Fundus

Claims

[1] Ophthalmic observation device comprising: an optical photography system comprising a first focusing lens and performing photography to capture a front image of an eye; an optical measuring system that includes a second focusing lens and performs optical coherence tomography (OCT) to capture a cross-sectional image of the eye; an optical path coupler that couples the optical paths of the optical photography system and the optical measuring system at one point on the eye side of the first and second focusing lenses; a first drive to move the first focusing lens along an optical axis of the optical photography system; a second drive for moving the second focusing lens along an optical axis of the optical measuring system; and a control system that individually controls the first and second drives, wherein the optical measurement system OCT performs the acquisition of a cross-sectional image of the fundus of the eye, and which further comprises: an optical projection system that projects a focusing index onto the fundus as an indication of a focus state of the optical photography system on the fundus; and an intensity reference element that references the intensity of an interference signal detected by the optical measurement system, wherein After focusing the optical photography system and focusing the optical measuring system based on the focusing index, the control system controls the second drive based on the intensity referenced by the intensity reference element. wherein the controller acquires multiple interference signals corresponding to multiple positions of the second focusing lens by controlling the optical measuring system while controlling the second drive to move the second focusing lens, has a fourth target position reference part which obtains a target position of the second focusing lens based on intensities of the multiple interference signals obtained by the intensity reference part, and controls the second drive to move the second focusing lens to the obtained target position. [2] Ophthalmic observation device according to claim 1, wherein the fourth target position reference part specifies the maximum intensity among the intensities of the multiple interference signals and defines a position of the second focusing lens corresponding to the specified maximum intensity as the target position. [3] Ophthalmic observation device according to claim 1 or 2, wherein the control moves the second focusing lens in a predetermined area to detect the multiple interference signals. [4] Ophthalmic observation device according to claim 3, wherein the predetermined area has a position of the second focusing lens which is predetermined on the basis of the focusing index. [5] Ophthalmological observation device according to claim 4, wherein the center of the predetermined area is located at the predetermined position. [6] Ophthalmological observation device according to any one of claims 1 to 5, further comprising an optical infrared photography system which uses infrared light to perform photography to capture a front image of a fundus of the eye, wherein the control performs focusing of the optical photography system by moving the first focusing lens and the optical projection system on the basis of the front image which is captured by photographing the fundus on which the focusing index is projected using the optical infrared photography system, and on the basis of the result of this focusing performs focusing of the optical measuring system. [7] Ophthalmic observation device which features: an optical photography system that includes a first focusing lens and performs photography to capture a frontal image of an eye; an optical measuring system that includes a second focusing lens and performs optical coherence tomography (OCT) to capture a cross-sectional image of the eye; an optical path coupler that connects the optical paths of the optical photography system and the optical measuring system at a point on the eye side of the first and couples to the second focusing lens; a first drive to move the first focusing lens along an optical axis of the optical photography system; a second drive for moving the second focusing lens along an optical axis of the optical measuring system; and a control system that individually controls the first and second drives, wherein the optical measurement system OCT performs the acquisition of a cross-sectional image of the fundus of the eye, and which further comprises: a memory that stores a pre-measured value of the eye's refractive power; and an intensity reference element that relates the intensity of an interference signal detected by the optical measurement system, wherein after focusing the optical photography system and Focusing the optical measuring system based on the measured value; the control system controls the second drive based on the intensity referenced by the intensity reference part.

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