JP2019063085A - Ophthalmic medical device - Google Patents

Abstract

To provide an ophthalmic medical device capable of appropriately acquiring information on a tissue of an eye to be examined.SOLUTION: A medical device 1 includes a wavelength sweeping light source 11, a branching optical element 12, an irradiation optical system 20, a multiplex optical element 18, a two-dimensional light receiving element 26, and a CPU 51. The wavelength sweeping light source 11 emits a laser beam in which an emission wavelength is temporally swept. The branching optical element 12 branches the laser beam emitted from the wavelength sweeping light source 11 into a measurement light and a reference light. The irradiation optical system 20 irradiates the measurement light onto a two-dimensional irradiation region on a tissue of a patient's eye E. The multiplex optical element 18 multiplexes the measurement light reflected by the irradiation region with the reference light, and causes the two lights to interfere with each other. The two-dimensional light receiving element 26 receives an interference light generated by the multiplex optical element 18. The irradiation optical system 20 is provided with a scanning part 22. The scanning part 22 moves the two-dimensional irradiation region onto which the measurement light is irradiated by changing the deflection direction of the measurement light.SELECTED DRAWING: Figure 1

Description

  The present disclosure is an ophthalmic medical device that acquires information on an object based on the principle of optical coherence tomography (OCT) by irradiating the object with measurement light and receiving reflected light reflected by the object. About.

  Conventionally, an object (for example, a tissue of an eye to be examined) is irradiated with measurement light, and information on the object (for example, data of a tomographic image of the object, deformation of the object, etc.) by reflected light of the measurement light and reference light The technology to acquire at least one of the above is known. For example, Non-Patent Document 1 discloses a technique for imaging the physiological response of a photoreceptor to stimulation of visible light using FF-SS-OCT (Full field-Swept source-Optical Coherence Tomography). There is.

“In vivo optical imaging of physiological responses to photostimulation in human photoreceptors”, PNAS Early Edition, pp. 1-6, 2016

  According to FF-SS-OCT, an OCT signal in a two-dimensional irradiation area is acquired in a short time by irradiating measurement light on the two-dimensional irradiation area on a subject. However, it is difficult to widen the irradiation area of the measurement light in FF-SS-OCT, and it is not easy to move the two-dimensional irradiation area. Moreover, in the case of acquiring an OCT signal by scanning a minute spot of measurement light within a two-dimensional area, it takes time to scan the spot.

  The present disclosure is to provide an ophthalmic medical device capable of appropriately acquiring information on the tissue of an eye to be examined.

  An ophthalmic medical device provided by an exemplary embodiment of the present disclosure is an ophthalmic medical device for acquiring information on a tissue of an eye to be examined, and a wavelength sweep that emits laser light whose emission wavelength is swept in time. A light source, a branching optical element for branching the laser light emitted from the wavelength-swept light source into a measurement light and a reference light, and the measurement light branched by the branching optical element on the tissue of the eye to be examined An irradiation optical system for irradiating a two-dimensional irradiation area, and a multiplexing optical element for combining and interfering the measurement light reflected by the two-dimensional irradiation area and the reference light branched by the branching optical element; A two-dimensional light receiving element that detects an interference signal in the two-dimensional irradiation area by receiving the interference light generated by the multiplexing optical element; and a control unit that controls the ophthalmic medical apparatus. Wherein the irradiation optical system, by changing the polarization direction of the measurement light, comprising a scanning unit for the measurement light moves the irradiation area of the two-dimensional emitted.

  According to the ophthalmic medical device in the present disclosure, information on the tissue of the eye to be examined is appropriately acquired.

FIG. 1 is a diagram showing a schematic configuration of a medical device 1. It is a flowchart of deformation amount calculation processing. It is a figure which shows an example of the front image 60 of the ocular fundus containing the irradiation area | region 61 of measurement light, and the irradiation position 62 of therapeutic light. It is a flowchart of panorama data acquisition processing. FIG. 6 is a view exemplifying a relationship between a panorama data acquisition area 71 set on a front image 70 and a plurality of irradiation areas 61 in the panorama data acquisition area 71. FIG. 6 is a view showing a state in which panorama data 81 is superimposed and displayed on a front image 70.

<Overview>
The medical device exemplified in the present disclosure (for example, an ophthalmic medical device) includes a wavelength swept light source, a branching optical element, an irradiation optical system, a multiplexing optical element, a two-dimensional light receiving element, and a control unit. The wavelength swept light source emits a laser beam whose emission wavelength is swept in time. The branching optical element branches the laser light emitted from the wavelength swept light source into the measurement light and the reference light. The irradiation optical system irradiates the two-dimensional irradiation area on the object (for example, the tissue of the eye to be examined) with the measurement light branched by the branching optical element. The multiplexing optical element combines and interferes with the measurement light reflected by the two-dimensional illumination area and the reference light branched by the branching optical element. The two-dimensional light receiving element includes a plurality of pixels arranged in a two-dimensional manner, and detects an interference signal in the irradiation area by receiving the interference light generated by the multiplexing optical element. The control unit is responsible for control of the ophthalmic medical device. The illumination optical system comprises a scanning unit. The scanning unit moves the two-dimensional irradiation area on which the measurement light is irradiated by changing the deflection direction of the measurement light.

  The ophthalmic medical device according to the present disclosure can acquire an OCT signal in a two-dimensional irradiation area by FF-SS-OCT, and scan (move) the irradiation area by the scanning unit. Therefore, it is easy to acquire an OCT signal in a wide range of tissues in a short time, and it is also easy to move the irradiation area. Thus, information about the organization is properly acquired.

  The control unit irradiates the measurement light to the tissue to which energy is applied to calculate the amount of deformation of the tissue which can be caused by the application of energy based on the interference signal detected by the two-dimensional light receiving element. May be In this case, after the OCT signal in a wide range of tissue is acquired based on the interference signal detected by the two-dimensional light receiving element, the amount of deformation of the tissue is calculated. Therefore, the amount of deformation of tissue is calculated more appropriately.

  In the present disclosure, for example, a treatment laser beam emitted from a laser treatment unit is used as energy to be applied to a tissue. In the present disclosure, the treatment laser beam is at least one of photocoagulation treatment of the fundus of the eye to be examined and minimally invasive treatment (sometimes referred to as thresholded coagulation treatment) which is treatment to the extent that fundus tissue does not coagulate. Used to do. However, the energy applied to the tissue is not limited to the therapeutic light. For example, mechanical energy may be externally applied by a piezoelectric element or the like. Energy may be applied by ultrasonic waves, electromagnetic waves, wind pressure or the like.

  Also, a method of calculating the amount of deformation of the tissue can be appropriately selected. As an example, in the present disclosure, the control unit acquires a plurality of OCT signals at different times by the interference light of the reference light and the measurement light reflected by the two-dimensional irradiation region. The control unit processes the plurality of OCT signals to calculate the time change rate of the local optical path length of the measurement light. The control unit calculates the amount of deformation of the tissue by calculating the accumulated amount of deformation (≧ 0) of the tissue in the irradiation area in the time direction based on the temporal change rate of the local optical path length. As a result, the transition of the change of the living tissue is properly grasped. However, it is also possible to change the method of calculating the amount of deformation of the tissue. For example, based on the OCT signal before the energy is applied and the OCT signal after the application of the energy is started, the control unit controls the tissue between two time points before and after the application of the energy is started. The amount of deformation may be calculated.

  The control unit may calculate the deformation amount of the tissue at a plurality of positions in the two-dimensional inspection target area included in the two-dimensional irradiation area. In this case, the user (for example, a doctor or the like) can appropriately grasp the transition of the deformation of the tissue in the two-dimensional inspection target area based on the calculation result. Therefore, compared with the case where the amount of deformation of one point on the tissue is calculated, the deformed state of the tissue is more appropriately grasped. However, the control unit may calculate the amount of deformation of one point of tissue in the irradiation area based on FF-SS-OCT.

  The ophthalmic medical device may include a laser irradiation unit that irradiates treatment laser light to the tissue. The control unit may control the irradiation of the treatment laser light to the tissue based on the calculated amount of deformation of the tissue. In this case, the irradiation of the therapeutic light is appropriately controlled based on the amount of deformation of the tissue.

  The control unit may calculate the deformation amount of one or more specific layers among the plurality of layers included in the fundus. In this case, the state of deformation of a specific layer in the fundus is appropriately grasped.

  Note that various diagnoses and treatments can be performed by using the deformation amount of a specific layer. For example, the control unit may control the irradiation of the treatment laser light based on the deformation amount of the specific layer. In this case, the irradiation of the treatment laser light is more appropriately controlled.

  More specifically, the control unit may calculate the amount of deformation of at least one of the retinal pigment epithelium (RPE) and the Bruch's membrane in the fundus, and control the irradiation of the treatment laser light based on the calculated amount of deformation. Retinal pigmented epithelium and Bruch's membrane tend to absorb therapeutic laser light. Therefore, by controlling the irradiation of the treatment laser light based on the deformation amount of the retinal pigment epithelium and the Bruch's membrane, the treatment laser light is more appropriately irradiated to the fundus. For example, the control unit may stop the irradiation of the treatment laser light when the deformation amount of at least one of the retinal pigment epithelium and the Bruch's membrane exceeds a threshold.

  The control unit may calculate the amount of deformation of at least a part of the retina inner layer in the fundus, and control the irradiation of the treatment laser light based on the calculated amount of deformation. Since the inner retinal layer contains many cells associated with visual function, it is preferable to suppress degeneration of the inner retinal layer by the treatment laser light. Therefore, by controlling the irradiation of the treatment laser light based on the deformation amount of the inner retina, the treatment laser light is more appropriately irradiated to the fundus. For example, when the deformation amount of at least part of the inner retina layer exceeds the threshold, the control unit may suppress the degeneration of the inner retina layer by stopping the irradiation of the treatment laser light.

  The control unit may acquire the interference signal in each of the plurality of irradiation areas by irradiating the measurement light to each of the plurality of irradiation areas that do not completely overlap each other. The control unit may generate data of an area wider than each irradiation area by aligning a plurality of data obtained based on each of the plurality of acquired interference signals. In this case, data of a wider range of tissues are appropriately acquired based on FF-SS-OCT.

  In this case, various data can be adopted as “data obtained based on the interference signal”. For example, the control unit may acquire a two-dimensional or three-dimensional tomographic image in each irradiation region based on each interference signal, and align the acquired plural tomographic images. In addition, the control unit acquires OCT front (Enface) image data when each irradiation area is viewed from the direction (front direction) along the optical axis of the measurement light based on each interference signal, and a plurality of acquired OCT frontal image data may be aligned. Further, the control unit may acquire motion contrast data indicating the movement of the tissue in each irradiation region based on each interference signal, and align the acquired plurality of motion contrast data. Further, the control unit may obtain various analysis data (for example, map data indicating a two-dimensional distribution of the thickness of a specific layer, etc.) based on each interference signal, and may perform alignment.

  The control unit acquires a front image of the tissue when viewed from the direction along the optical axis of the measurement light, and based on the acquired front image, positions the irradiation area to be irradiated with the measurement light at the same position on the tissue. You may make it follow. That is, the control unit may perform tracking of the irradiation area. In this case, even when the tissue moves, the measurement light is irradiated to an appropriate position.

  The ophthalmic medical device may not include the scanning unit that moves the irradiation region when calculating the amount of deformation of the tissue by the principle of FF-SS-OCT. Even in this case, the ophthalmic medical device can easily acquire the OCT signal of a wide range of tissue as compared with the case of scanning a minute spot, and therefore the deformation amount of the tissue can be calculated more appropriately. In addition, the ophthalmic medical device may calculate the amount of deformation of tissue based on the principle of line field OCT (hereinafter referred to as "LF-OCT"). In LF-OCT, measurement light is simultaneously irradiated on an irradiation line extending in a one-dimensional direction in tissue, and the reflected light of the measurement light and the interference light of the reference light are one-dimensional light receiving elements (for example, line sensors) or two-dimensional light receiving elements It is received by. Therefore, even in the case of using LF-OCT, OCT signals of a wide range of tissues can be easily obtained as compared with the case of scanning a minute spot. Therefore, the deformation amount of the tissue is more appropriately acquired. When using the principle of LF-OCT, the ophthalmic medical device may comprise a scanning unit.

  In these cases, the ophthalmic medical device can also be expressed as follows. An ophthalmic medical apparatus for acquiring information on a tissue of an eye to be examined, comprising: a light source for emitting a laser beam; a branching optical element for branching the laser beam emitted from the light source into measurement light and reference light; An irradiation optical system for irradiating the measurement light branched by the branching optical element onto an irradiation line extending in one dimension in the tissue of the subject's eye or a two-dimensional irradiation area on the tissue of the subject's eye; A multiplexing optical element for combining the interference of the measurement light reflected by the line or the irradiation area and the reference light branched by the branching optical element; and the interference light generated by the multiplexing optical element A light receiving element that receives light, and a control unit that controls control of the ophthalmic medical apparatus, the control unit irradiating the measurement light to the tissue to which energy is applied, The amount of deformation of the tissue which may occur by serial energy is applied, it is calculated based on the interference signal detected by the light receiving element.

Embodiment
Hereinafter, one of the typical embodiments of the present disclosure will be described with reference to the drawings. As an example, the medical device 1 of the present embodiment is an ophthalmic medical device that acquires information on the fundus of the eye to be examined E. Further, the medical device 1 of the present embodiment can also treat the fundus by irradiating the fundus with the treatment laser light. However, at least a part of the technique exemplified in the present embodiment can also be applied to the case of acquiring information on the tissue of the eye to be examined E other than the fundus. In addition, even in the case of acquiring information on an object other than the eye to be examined E (for example, skin, digestive tract, brain, etc.), at least a part of the techniques exemplified in the present embodiment can be applied. Moreover, the medical device 1 may not be provided with the structure which irradiates a treatment laser beam. That is, the medical device 1 may perform only acquisition of information (for example, data of a tomographic image of an object, etc.) regarding the object without performing treatment.

  Further, the medical device 1 of the present embodiment includes an OCT unit 10, a laser treatment unit 30, a front image photographing unit 40, and a control unit 50. However, at least a part of the configuration exemplified in the present embodiment may be provided in a device different from the medical device provided with the OCT unit 10. For example, the medical device provided with the OCT unit 10 and the laser treatment device provided with the laser treatment unit 30 may be separately provided. Also, a device (e.g., a personal computer, etc.) connected to the medical device may control the medical device.

<Schematic configuration>
The schematic configuration of the medical device 1 of the present embodiment will be described with reference to FIG. As described above, the medical device 1 of the present embodiment includes the OCT unit 10, the laser treatment unit 30, the front image photographing unit 40, and the control unit 50.

  The OCT unit 10 will be described. The OCT unit 10 acquires an OCT signal using the principle of optical coherence tomography (OCT). The OCT unit 10 includes a wavelength sweeping light source 11, a branching optical element 12, an irradiation optical system 20, a multiplexing optical element 18, and a two-dimensional light receiving element 26.

  The wavelength sweeping light source (SS light source) 11 emits laser light in which the emission wavelength is swept at high speed as time passes. The wavelength swept light source 11 may include, for example, a laser medium, a resonator, and a wavelength selection filter. As the wavelength selection filter, for example, a combination of a diffraction grating and a polygon mirror, or a filter using a Fabry-Perot etalon may be used.

  The branching optical element 12 branches the laser light emitted from the wavelength sweeping light source 11 into measurement light and reference light. As an example, the branch optical element 12 of the present embodiment is a fiber coupler. However, an element other than a fiber coupler (for example, a circulator, a beam splitter, etc.) may be used as the branching optical element 12.

  In the present embodiment, the measurement light branched by the branching optical element 12 is guided to the measurement light fiber 13, and the reference light is guided to the reference light fiber 14. When the measurement light is emitted from the measurement light fiber 13, the measurement light is converted into parallel light by the collimator lens 15, and then enters the multiplexing optical element 18 (details will be described later) which is a beam splitter. At least a portion of the measurement light is reflected by the multiplexing optical element 18 and guided to the irradiation optical system 20. In addition, when the reference light is emitted from the reference light fiber 14, the reference light is collimated by the collimator lens 16 and then enters the multiplexing optical element 18. At least a portion of the reference light is reflected by the multiplexing optical element 18 and guided to the two-dimensional light receiving element 26.

  The OCT unit 10 includes an optical path length difference adjustment unit 17 that adjusts the optical path length difference between the measurement light and the reference light. By adjusting the optical path length difference, the range in the depth direction (the Z direction along the optical axis of the measurement light) at which the OCT signal is acquired is changed. The optical path length difference adjustment unit 17 is provided on at least one of the optical path of the measurement light and the optical path of the reference light. As an example, the optical path length difference adjustment unit 17 of the present embodiment is a motor, and adjusts the optical path length difference by moving the downstream end of the reference light fiber 14 and the collimator lens 16 in the optical axis direction.

  The irradiation optical system 20 irradiates the two-dimensional irradiation area on the tissue of the eye E with the measurement light branched by the branching optical element 12. That is, in the present embodiment, the measurement light is irradiated to the tissue in a state of being spread in a two-dimensional direction intersecting the optical axis, not to be a minute spot to be irradiated to the tissue. As an example, in the present embodiment, the shape of the irradiation area is also formed in a rectangular shape in accordance with the shape (rectangular in the present embodiment) of the light receiving surface of the two-dimensional light receiving element 26 described later. However, it goes without saying that the shape of the irradiation area is not limited to a rectangle. The irradiation optical system 20 of the present embodiment includes lenses 21, 24 and 25 and a scanning unit 22. The lens 21 focuses the measurement light guided from the multiplexing optical element 18 as a parallel light beam.

  The scanning unit 22 is driven by the driving unit 23 to change the deflection direction of the measurement light. As a result, the position of the two-dimensional irradiation area on which the measurement light is irradiated on the tissue is moved. In the present embodiment, the scanning unit 22 is provided at a position substantially conjugate to the pupil of the eye to be examined E. Further, in the present embodiment, two galvanometer mirrors (only one galvanometer mirror is illustrated in FIG. 1) capable of deflecting the measurement light in different directions are used as the scanning unit 22. However, another device for deflecting light (for example, at least one of a polygon mirror, a resonant scanner, an acousto-optic element, etc.) may be used as the scanning unit 22. The lenses 24 and 25 conjugately couple the position of the scanning unit 22 and the pupil of the eye to be examined E. A diaphragm may be provided between the lens 25 and the eye E.

  The measurement light reflected by the two-dimensional irradiation area on the tissue returns in the opposite direction to the same optical path as the optical path of the measurement light when it is irradiated toward the eye E and enters the multiplexing optical element 18. The multiplexing optical element 18 of the present embodiment is a beam splitter, and transmits at least a part of the measurement light reflected by the irradiation area. As a result, the measurement light reflected by the irradiation area and transmitted through the multiplexing optical element 18 and the reference light reflected by the multiplexing optical element 18 through the lens 16 are multiplexed and interfere with each other. The interference light generated by the multiplexing optical element 18 is incident on the two-dimensional light receiving element 26.

  The two-dimensional light receiving element 26 includes a plurality of pixels arranged two-dimensionally. The interference light enters the two-dimensional light receiving element 26 from the multiplexing optical element 18 in a substantially parallel light state, and is detected by a plurality of pixels provided in the two-dimensional light receiving element 26. As a result, an interference signal of each position in the two-dimensional illumination area is acquired without scanning the measurement light. By Fourier-transforming the interference signal acquired by the two-dimensional light receiving element 26, an OCT signal (complex OCT signal) in the two-dimensional irradiation area is obtained. For example, a two-dimensional CCD, a two-dimensional CMOS, or the like can be employed as the two-dimensional light receiving element 26.

  The laser treatment unit 30 will be described. The laser treatment unit 30 emits treatment light (in the present embodiment, treatment laser light). As an example, in the present embodiment, the treatment light emitted from the laser treatment unit 30 is a photocoagulation treatment of the fundus of the eye E to be examined and a subthreshold coagulation treatment in which the treatment light is irradiated with energy to such an extent that the fundus tissue is not coagulated. Used to perform at least one of In the present embodiment, the dichroic mirror 28 is provided on the optical path of the measurement light in the OCT unit 10. The treatment light emitted by the laser treatment unit 30 is reflected by the dichroic mirror 28 and irradiated to the living tissue. The laser treatment unit 30 of the present embodiment includes a scanning unit that moves the irradiation position of the treatment light by changing the deflection direction of the treatment light. The control unit 50 can also cause the treatment light to be sequentially irradiated to each of a plurality of positions on the tissue by controlling the drive of the scanning unit of the laser treatment unit 30. Further, when movement of tissue is detected, the control unit 50 can also make the irradiation position of the treatment light follow the detected movement.

  The medical device 1 can acquire an OCT signal by the OCT unit 10 while irradiating the treatment light to the living tissue by the laser treatment unit 30. In addition, the structure required in order to perform irradiation of a therapeutic light and acquisition of an OCT signal in parallel can be selected suitably. For example, an optical system for irradiating the living tissue with the OCT measurement light and an optical system for irradiating the therapeutic light to the living tissue may be provided independently of each other.

  The front image capturing unit 40 is provided to obtain a front image of a living tissue (in the present embodiment, at least the fundus of the patient's eye E). That is, the front image capturing unit 40 captures an image of a tissue when viewed from the direction along the optical axis of the measurement light. For example, at least one of a scanning laser ophthalmoscope (SLO) and a fundus camera can be adopted as the configuration of the front image capturing unit 40. In the present embodiment, the dichroic mirror 29 is provided on the optical path between the dichroic mirror 28 and the laser treatment unit 30. The light for capturing the front image is incident on the front image capturing unit 40 from the tissue through the dichroic mirror 28 and the dichroic mirror 29.

  The control unit 50 will be described. The control unit 50 manages various controls of the medical device 1. The control unit 50 includes a CPU 51, a RAM 52, a ROM 53, and a non-volatile memory (NVM) 54. The CPU 51 is a controller that performs various controls. The RAM 52 temporarily stores various information. The ROM 53 stores programs executed by the CPU 51, various initial values, and the like. The NVM 54 is a non-transitory storage medium capable of retaining stored contents even when the supply of power is shut off. A medical device control program for executing deformation amount calculation processing (see FIG. 2) and panoramic data acquisition processing (see FIG. 4) described later may be stored in the NVM 54. As described above, the control unit that executes the cumulative deformation amount calculation process does not have to be provided in the medical device 1. For example, at least one of a control unit such as a PC, an OCT apparatus, or a laser treatment apparatus may execute the deformation amount calculation process and the panoramic data acquisition process.

<Deformation amount calculation processing>
The deformation amount calculation process will be described with reference to FIGS. 2 and 3. In the deformation amount calculation processing, the deformation amount of the tissue (the fundus of the eye to be examined E in the present embodiment) is calculated using the principle of OCT (FF-SS-OCT in the present embodiment). Furthermore, in the deformation amount calculation process of the present embodiment, the irradiation of the treatment light is controlled based on the calculated deformation amount. The CPU 51 of the control unit 50 executes the deformation amount calculation process shown in FIG. 2 in accordance with the medical device control program stored in the NVM 54.

  First, the CPU 51 sets an irradiation area 61 (see FIG. 3) of measurement light on a tissue and an irradiation position 62 (see FIG. 3) of treatment light (S1). FIG. 3 is a view showing an example of a front image 60 of the fundus including the irradiation region 61 of the measurement light and the irradiation position 62 of the treatment light. In the front image 60 illustrated in FIG. 3, a fundus including the optic papilla 2, the macula 3 and the fundus blood vessel 4 appears. As shown in FIG. 3, the medical device 1 according to this embodiment does not scan a minute spot of measurement light on the fundus, but simultaneously irradiates the measurement light to a two-dimensional irradiation area 61 on the fundus. , OCT signal in the irradiated area is detected. As described above, the irradiation area 61 illustrated in FIG. 3 is rectangular. Further, the shape of the spot of the treatment light is formed in a rectangular shape by a square fiber or the like in accordance with the shape of the irradiation area 61. However, it is also possible to make at least one of the irradiation area 61 and the shape of the spot of the treatment light into a two-dimensional shape (for example, a circle etc.) other than a rectangle.

  In addition, the method to set the irradiation area | region 61 of measurement light and the irradiation position 62 of therapeutic light can be selected suitably. For example, aiming light indicating the position of the irradiation area 61 and the irradiation position 62 may be irradiated on the tissue. Even when the user operates the operation unit (not shown) while looking at the front image 60 in which the aiming light is reflected, even if the position of the irradiation area 61 and the irradiation position 62 of the treatment light are input to the medical device 1 Good. The CPU 51 may set the position of the irradiation area 61 of the measurement light and the irradiation position 62 of the treatment light according to the input operation instruction. Along with the position of the irradiation area 61, at least one of the size, the shape, and the angle of the irradiation area 61 may be set according to the operation instruction input from the user. The user may move the irradiation area 61 and the irradiation position 62 while observing the tissue using a slit lamp or the like. Further, only the irradiation position 62 of the treatment light may be set according to the operation instruction input from the user. In this case, the irradiation area 61 of the measurement light may be set based on the irradiation position 62 of the treatment light. For example, the irradiation area 61 of the measurement light may be set to an area centered on the irradiation position 62 of the treatment light. In addition, the irradiation area | region 61 of measurement light and the irradiation position 62 of therapeutic light do not need to overlap.

  Further, in the example shown in FIG. 3, one irradiation position 62 of the treatment light is set in the irradiation region 61 of the measurement light. However, a plurality of irradiation positions 62 of the treatment light may be set in the irradiation region 61 of the treatment light. In this case, the CPU 51 may control the scanning unit of the laser treatment unit 30 to sequentially irradiate the treatment light to each of the plurality of irradiation positions 62. Further, the treatment light may be simultaneously irradiated to a plurality of irradiation positions 62. The medical device 1 can appropriately detect the change of the tissue in the irradiation area 61 when the treatment light is irradiated to the plurality of irradiation positions 62 by the principle of FF-SS-OCT.

  Next, the CPU 51 starts detection of an OCT signal for the two-dimensional irradiation area 61 (see FIG. 3) on the tissue (S2). The measurement light reflected by the irradiation area 61 is multiplexed with the reference light and interferes, and the interference light is received by the two-dimensional light receiving element 26. The CPU 51 Fourier-transforms each interference signal output from each pixel of the two-dimensional light receiving element 26 to detect an OCT signal (complex OCT signal) at each position in the irradiation area 61 corresponding to each pixel. . The detection of the OCT signal with respect to the irradiation area 61 is intermittently repeated.

  In the present embodiment, the position and size of the two-dimensional area (hereinafter referred to as “the area to be inspected”) on the tissue for acquiring the OCT signal is the position of the two-dimensional irradiation area 61 to which the measurement light is irradiated. And identical in size. However, the inspection target area may be a partial area in the irradiation area 61.

  Next, the CPU 51 detects the movement amount of the tissue (fundus oculi in the present embodiment) from the front image 60 (S3). As an example, the CPU 51 of the present embodiment processes a front image 60 (hereinafter, referred to as “real time image”) captured in real time, and generates a reference site (for example, optic nerve 2, macular 3 and fundus blood vessel 4) in the real time image. And a reference region of a front image 60 (hereinafter referred to as a “reference image”) captured before the real-time image. As a result, the movement amount of the tissue at the time of real-time image shooting with respect to that at the time of reference image shooting is detected. "Movement" may include movement in a rotational direction about an axis parallel to the optical axis, in addition to movement in the XY directions intersecting the shooting optical axis of the front image.

  The CPU 51 controls the drive of the scanning unit 22 based on the movement amount of the tissue detected in S2 to make the position of the irradiation region 61 of the measurement light follow the same position on the tissue (S4). That is, the CPU 51 starts tracking of the irradiation area 61. As a result, even when the tissue moves, measurement light is emitted to an appropriate position. Further, the CPU 51 controls the drive of the scanning unit of the laser treatment unit 30 based on the movement amount of the tissue to make the irradiation position 62 of the treatment light follow the same position on the tissue. That is, the CPU 51 starts tracking of the irradiation position 62 of the treatment light.

  The CPU 51 starts the irradiation of the treatment light (the treatment laser light in the present embodiment) to the tissue (S5). As an example, in the present embodiment, as shown in FIG. 3, the inside (the central portion in the present embodiment) of the irradiation region 61 of the measurement light is set to the irradiation position 62 of the treatment light.

  The CPU 51 acquires a plurality of OCT signals intermittently detected at each of a plurality of positions in the inspection target area (that is, in the irradiation area 61 in the present embodiment) (S6). The CPU 51 calculates the deformation amount of a specific layer in the fundus at each of a plurality of positions in the examination area (S7).

  In addition, the method of calculating the deformation amount of the tissue at each position can be selected appropriately. Hereinafter, an example of a method of calculating the amount of deformation of tissue at each position will be described. In the present embodiment, the CPU 51 calculates the time change rate (hereinafter referred to as “local light path length change rate”) of the local optical path length (IOPL) of a specific layer at each position. Furthermore, the CPU 51 calculates the cumulative deformation amount of a specific layer of tissue at each position by integrating the absolute value of the local optical path length change rate in the Z direction.

  In detail, the CPU 51 of the present embodiment time-differentiates a plurality of OCT signals at each position. Time differentiation may be performed, for example, by multiplying the OCT signal Γ by a value obtained by shifting it by Δt (t is time) and taking a complex conjugate. Next, the CPU 51 spatially differentiates the obtained value. The spatial differentiation may be performed, for example, by shifting a value obtained by temporal differentiation by Δm pixels in the depth direction, multiplying by a complex conjugate, and extracting its phase. Next, the CPU 51 calculates the local light path length change rate. The local optical path length is the optical path length of the OCT measurement light that has been incident on and reflected at respective local portions that differ in position in the depth direction (Z direction). Next, the CPU 51 integrates the absolute value of the local optical path length change rate in a specific layer in the Z direction. Furthermore, the CPU 51 accumulates values accumulated in the Z direction in the time direction. The cumulative deformation amount at each position is calculated by performing the above processing for each position in the inspection target area. As a result, the transition of the change of the tissue in the two-dimensional examination area is easily grasped from the obtained data.

  In the present embodiment, among the plurality of layers in the fundus, the deformation amount of at least one of the retinal pigment epithelium and the Bruch's membrane is calculated. Retinal pigmented epithelium and Bruch's membrane tend to absorb therapeutic light. Therefore, by calculating the deformation amount of at least one of the retinal pigment epithelium and the Bruch's membrane, the deformation of the tissue due to absorption of the therapeutic light can be grasped more appropriately.

  Further, the deformation amount of at least a part of the inner retina layer may be calculated among the plurality of layers in the fundus. Since the inner retinal layer contains many cells associated with visual function, it is preferable to suppress degeneration of the inner retinal layer by the treatment light. Therefore, by calculating the amount of deformation of at least a part of the inner retina, it is more appropriately grasped whether or not undesired degeneration has occurred.

  Needless to say, the method of calculating the amount of deformation of the tissue in this embodiment is an example. That is, it is also possible to change the method of calculating the amount of deformation. For example, the CPU 51 may include spatial derivatives of a plurality of OCT signals at the same time detected at each of a plurality of positions in the region to be inspected in the process of calculating the deformation amount. In this case, the transition of the change in the deformation amount between the plurality of positions is more appropriately grasped. Further, the CPU 51 starts the application of energy based on the OCT signal before the application of energy (in the present embodiment, the irradiation of the treatment light) is started and the OCT signal after the application of energy is started. The amount of tissue deformation between the two time points before and after being performed may be calculated. Further, the CPU 51 may calculate the deformation amounts of all the layers without being limited to the deformation amount of a specific layer in the fundus.

  Next, the CPU 51 controls the irradiation of the therapeutic light based on the calculated deformation amount (S8, S9). As an example, in the present embodiment, the CPU 51 determines whether the calculated cumulative deformation amount is equal to or greater than a threshold (S8). The threshold may be appropriately set according to the therapeutic purpose (for example, which of the photocoagulation treatment and the thresholded coagulation treatment is to be performed) or the like. For example, the CPU 51 may determine whether or not the sum of accumulated deformation amounts of all positions in the inspection target area is equal to or greater than a threshold. In addition, the CPU 51 determines whether or not the cumulative deformation of a specific position in the examination area (for example, the center of the examination area, the end of the examination area, the irradiation position 62 of the treatment light, etc.) You may decide If the accumulated deformation amount is less than the threshold (S8: NO), the process returns to S6, and the process of calculating the accumulated deformation amount (S6, S7) is repeated while continuing the irradiation of the treatment light. If the cumulative deformation amount is equal to or greater than the threshold (S8: YES), the CPU 51 stops the irradiation of the treatment light (S9), and ends the process. When a plurality of irradiation positions 62 of the treatment light are set, the processes of S6 to S8 may be repeated until the irradiation of the treatment light to all the irradiation positions 62 is completed.

<Panorama data acquisition process>
The panorama data acquisition process will be described with reference to FIGS. 4 to 6. In the panoramic data acquisition processing, interference signals in each of the plurality of irradiation areas 61 are acquired using the principle of OCT (FF-SS-OCT in the present embodiment). Furthermore, a plurality of OCT data are acquired based on the interference signal in each irradiation area 61, and panoramic data is generated by aligning the plurality of OCT data.

  Here, panoramic data is OCT data in a wider range than one irradiation area 61. Moreover, various data can be adopted as OCT data acquired based on an interference signal. For example, OCT data may be two-dimensional or three-dimensional tomographic image data. The OCT data may be OCT front (Enface) image data when the tissue is viewed from the direction (front direction) along the optical axis of the measurement light. Also, the OCT data may be motion contrast data indicating movement of tissue. The OCT data may also be various analysis data (for example, map data indicating a two-dimensional distribution of the thickness of a specific layer, etc.) obtained based on the interference signal.

  As an example, in this embodiment, a case of generating panorama data of motion contrast data will be described. The CPU 51 executes the panoramic data acquisition process shown in FIG. 4 in accordance with the medical device control program stored in the NVM 54.

  First, the CPU 51 sets an area on the organization (hereinafter referred to as "panorama data acquisition area 71") for acquiring the panorama data 81 (see FIG. 6) (S11). The method of setting the panoramic data acquisition area 71 can be selected as appropriate. FIG. 5 is a diagram illustrating the relationship between the panoramic data acquisition area 71 set on the front image 70 and the plurality of irradiation areas 61 in the panoramic data acquisition area 71. For example, by operating the operation unit (not shown), the user operates at least one of the position, size, shape, and angle of the panoramic data acquisition region 71 on the front image 70 of the tissue (fundus oculi in the present embodiment). You may enter an instruction to specify The CPU 51 may set the panoramic data acquisition area 71 on the tissue in accordance with the input instruction.

  Further, in S11, when setting the panorama data acquisition area 71, the CPU 51 sets a plurality of irradiation areas 61 on the tissue so that the whole of the set panorama data acquisition area 71 is covered by the plurality of irradiation areas 61. The plurality of irradiation areas 61 are set so as not to completely overlap each other. In the example shown in FIG. 5, a plurality of irradiation areas 61 are set such that adjacent irradiation areas 61 are in contact with each other. However, the areas of the end portions of adjacent irradiation areas 61 may overlap. In the example shown in FIG. 5, a total of nine irradiation areas 61 from the first to the ninth are set in the panorama data acquisition area 71.

  Next, the CPU 51 detects the movement amount of the tissue from the front image 70 (S12). The same method as S3 (see FIG. 2) described above may be adopted as a method of detecting the movement amount of tissue. The CPU 51 controls the drive of the scanning unit 22 based on the movement amount of the tissue detected in S12 to make the position of the irradiation position 61 of the measurement light follow the same position on the tissue (S13). That is, the CPU 51 starts tracking of the irradiation area 61. In the example shown in FIG. 5, the measurement light is sequentially irradiated to the first irradiation region 61 to the ninth irradiation region 61. Therefore, at the start of tracking, the irradiation position 61 of the measurement light follows the first position.

  Next, the CPU 51 detects an interference signal in a part of the irradiation area 61 in the panoramic data acquisition area 71 (the first irradiation area 61 in the example shown in FIG. 5) (S15). Next, if the detection of the interference signal in the whole area in the panoramic data acquisition area 71 is not completed (S16: NO), the CPU 51 controls the scanning unit 22 to next to the irradiation area 61 to which the measurement light is irradiated. It changes to the irradiation area 61 of (S17). In S17, the area to be tracked is also changed to the next irradiation area 61.

  When the detection of the interference signal in the whole area in the panoramic data acquisition area 71 is completed (S16: YES), the CPU 51 creates OCT data from the interference signal in each irradiation area 61 (S18). As an example, in the present embodiment, motion contrast data is created as OCT data. Therefore, in the process of S15, the CPU 51 acquires the interference signals of at least two frames having different measurement times from the respective irradiation areas 61 by irradiating the respective irradiation areas 61 with the measurement light a plurality of times. In S18, the CPU 51 performs operation processing on the acquired interference signals of a plurality of frames to create motion contrast data in each of the irradiation areas 61. Methods of processing interference signals to acquire motion contrast data include, for example, a method of calculating a phase difference of complex OCT signals, a method of calculating a vector difference of complex OCT signals, and a phase difference and vector of complex OCT signals. Although there is a method of multiplying differences, etc., any method may be adopted.

  Next, the CPU 51 generates panoramic data 81 by performing alignment of the respective OCT data (S19). FIG. 6 shows an example of a state in which panorama data 81 of motion contrast data is superimposed and displayed on the front image 70. As shown in FIG. 6, the panorama data 81 is generated by aligning a plurality of motion contrast data 82 corresponding to each irradiation position 61. Thus, OCT data of a wider range of tissues are properly acquired based on FF-SS-OCT.

  The techniques disclosed in the above embodiments are merely examples. Therefore, it is also possible to change the technique illustrated in the above embodiment. For example, in the above embodiment, the measurement light is irradiated to the two-dimensional irradiation area 61, whereby an interference signal is acquired by the principle of FF-SS-OCT. However, for example, when it is not necessary to perform tracking in the deformation amount calculation process illustrated in FIG. 2, the medical device 1 may not include the scanning unit 22.

  Moreover, when calculating the amount of deformation of tissue, the medical device 1 may calculate the amount of deformation of tissue by the principle of LF-OCT. That is, the medical device 1 simultaneously irradiates the measurement light on the irradiation line extending in one dimension in the tissue, and receives the interference signal of the reflected light of the measurement light and the reference light by the one-dimensional light receiving element or the two-dimensional light receiving element. Interference signals may be detected. In this case, the medical device 1 may acquire an interference signal in the two-dimensional irradiation area 61 by controlling the drive of the scanning unit 22 and moving the irradiation line. In addition, the structure of the medical device 1 in case the principle of LF-OCT is used can be selected suitably. For example, the wavelength swept light source 11 may be used as an OCT light source that emits measurement light and reference light as in the above embodiment. In this case, the light receiving element that receives the interference light may be a one-dimensional light receiving element. In addition, a low coherent light source (broadband light source) may be used as an OCT light source that emits measurement light and reference light. In this case, the ophthalmologic apparatus 1 may include a spectroscopic optical system that disperses the interference light into each frequency component, and a two-dimensional light receiving element that receives the dispersed light.

DESCRIPTION OF SYMBOLS 1 Medical device 11 Wavelength sweep light source 12 Branching optical element 18 Combined optical element 20 Irradiation optical system 22 Scanning part 26 Two-dimensional light receiving element 51 CPU
61 irradiation area 81 panorama data

Claims (6)

An ophthalmic medical device for acquiring information on a tissue of an eye to be examined,
A wavelength-swept light source for emitting a laser beam whose emission wavelength is swept in time;
A branching optical element that branches the laser light emitted from the wavelength swept light source into measurement light and reference light;
An irradiation optical system which irradiates the measurement light branched by the branching optical element on a two-dimensional irradiation area on the tissue of the eye to be examined;
A multiplexing optical element that multiplexes and interferes with the measurement light reflected by the two-dimensional irradiation area and the reference light branched by the branching optical element;
A two-dimensional light receiving element that detects an interference signal in the two-dimensional irradiation area by receiving the interference light generated by the multiplexing optical element;
A control unit that controls the ophthalmic medical device;
Equipped with
The irradiation optical system is
An ophthalmic medical apparatus comprising: a scanning unit configured to move the two-dimensional irradiation area irradiated with the measurement light by changing the deflection direction of the measurement light. The ophthalmic medical device according to claim 1, wherein
The control unit
By irradiating the measurement light to the tissue to which energy is applied, the amount of deformation of the tissue which may be caused by the application of the energy is calculated based on the interference signal detected by the two-dimensional light receiving element. An ophthalmic medical device characterized in that. The ophthalmic medical device according to claim 2, wherein
The control unit
An ophthalmologic medical device, comprising: calculating amounts of deformation of the tissue at a plurality of positions in a two-dimensional examination area included in the two-dimensional irradiation area. The ophthalmic medical device according to claim 2 or 3, wherein
The apparatus further comprises a laser irradiation unit that applies energy to the tissue by irradiating the tissue with a treatment laser beam,
The control unit
An ophthalmic medical device comprising: controlling irradiation of the treatment laser beam to the tissue based on the calculated amount of deformation of the tissue. The ophthalmic medical device according to any one of claims 2 to 4, wherein
The tissue is a fundus of the subject's eye,
The control unit
An ophthalmic medical device comprising: calculating an amount of deformation of one or more specific layers among a plurality of layers contained in the fundus. The ophthalmic medical device according to any one of claims 1 to 5, wherein
The control unit
By causing the scanning unit to irradiate the measurement light to each of the plurality of two-dimensional irradiation regions that do not completely overlap each other, interference signals in each of the plurality of irradiation regions are acquired.
An ophthalmic medical device characterized in that data of an area wider than each of the irradiation areas is generated by aligning a plurality of data obtained based on each of the plurality of interference signals.

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