JP2014104275A - Ophthalmologic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmologic apparatus capable of suitably diagnosing the state of at least one of a choroid or a retina of subject's eye.SOLUTION: An ophthalmologic apparatus includes: a light source; a measuring optical system for irradiating light from the light source to the interior of subject's eye and guiding a measuring beam from the interior of the subject's eye; a reference optical system for irradiating light from the light source to a reference surface and guiding the reflected light; a photo detecting element for receiving interference light which is composed of the measuring beam guided by the measuring optical system and the reflected light guided by the reference optical system; and an arithmetic device for outputting dynamic change of an index showing the form of at least one of the choroid and the retina on the basis of a plurality of eyeground tomographic images repeatedly obtained in a cycle shorter than the pulse wave from the interference light received by the photo detecting element at a preset position in the interior of the subject's eye.

Description

  The present specification relates to an ophthalmologic apparatus for inspecting an eye to be examined. In particular, the present invention relates to an ophthalmologic apparatus for diagnosing at least one state of the choroid and retina of an eye to be examined.

  An ophthalmologic apparatus for inspecting the inside of an eye to be examined has been developed. For example, Patent Document 1 discloses a technique for acquiring a fundus tomographic image including the choroid of the eye to be examined using optical coherence tomography (so-called OCT).

JP 2011-72716 A

  In the conventional technique, glaucoma is diagnosed by measuring the thickness of the choroid from the fundus tomographic image and comparing the measured thickness or evaluation value with a standard value. However, the thickness of the choroid obtained from the fundus tomographic image is the thickness of the choroid at the time of capturing the fundus tomographic image (instant), and it may be difficult to accurately diagnose the state of the choroid. That is, there are many blood vessels in the choroid, and the form such as the thickness of the choroid changes depending on the amount of blood flowing in the blood vessel. The amount of blood flowing in the blood vessel changes according to the movement of the heart. For this reason, if the thickness of the choroid is diagnosed from one fundus tomographic image, there is a possibility that the state of the choroid cannot be accurately diagnosed. The present specification discloses an ophthalmologic apparatus capable of appropriately diagnosing at least one state of the choroid and retina of an eye to be examined.

  An ophthalmologic apparatus disclosed in this specification irradiates a reference surface with a light source, a measurement optical system that irradiates light from the light source into the eye to be examined and guides measurement light from the inside of the eye to be examined, and light from the light source And a reference optical system that guides the reflected light, a light receiving element that receives interference light in which the measurement light guided by the measurement optical system and the reflected light guided by the reference optical system are combined, and the light receiving element Calculation that outputs dynamic changes in the index representing at least one of the choroid and retina based on multiple fundus tomographic images at a set position inside the subject's eye, repeatedly acquired from the interference light at a shorter cycle than the pulse wave I have a device.

  In this ophthalmologic apparatus, a fundus tomographic image is repeatedly acquired at a set position inside the eye to be examined at high speed, and a dynamic change of an index representing at least one of the choroid and retina is output from the plurality of fundus tomographic images. For this reason, even if the state of the choroid and / or retina changes dynamically or periodically due to changes in the amount of blood flowing through the blood vessels in the choroid, a plurality of fundus tomographic images reflecting the dynamic or periodic changes Is acquired. And since the dynamic change of the parameter | index showing the form of choroid and / or retina is output from the acquired several fundus tomographic images, the state of choroid and / or retina can be properly diagnosed.

The block diagram which shows the structure of an ophthalmologic apparatus. It is a figure which shows the structure of a tomographic image acquisition part. It is a figure which shows an example of the fundus tomographic image imaged by the tomographic image acquisition unit. It is a flowchart which shows an example of the process sequence of an ophthalmologic apparatus. It is a figure for demonstrating the example which outputs the blood flow velocity and blood vessel cross-sectional area of the blood which flows through the blood vessel in a choroid using a Doppler signal. It is a figure for demonstrating the example which outputs the blood flow rate of the blood which flows through the blood vessel in a choroid using a Doppler signal. It is a graph which shows together the time change of a pulse wave, and the time change of the thickness of a choroid. It is a figure which shows an example which frequency-analyzed the time change of the pulse wave and the time change of the thickness of the choroid.

  In the ophthalmologic apparatus disclosed in the present specification, the index indicating the form of at least one of the choroid and the retina is the choroid layer thickness specified from the fundus tomographic image, the retina layer thickness, the blood vessel diameter of at least one of the choroid and retina, And at least one of the blood vessel cross-sectional areas of at least one of the choroid and the retina. By using these indices, the state (morphology) of the choroid and / or retina can be appropriately evaluated.

  In the ophthalmologic apparatus disclosed in this specification, the arithmetic unit determines a region of the fundus tomographic image to be used when outputting the dynamic change of the index using the Doppler signal obtained from the interference light received by the light receiving element. May be. According to such a configuration, it is possible to output a dynamic change of the index using a limited region in the vicinity of the choroid and / or retina identified from the fundus tomographic image. For this reason, it is possible to appropriately evaluate the state (morphology) of the choroid and / or retina with a small amount of processing.

  The ophthalmologic apparatus disclosed in this specification may further include a pulse wave measuring unit that measures a pulse wave. The pulse wave measuring means may measure the pulse wave when repeatedly acquiring a plurality of fundus tomographic images. According to such a configuration, since the state of the pulse wave and the state of the choroid and / or retina can be evaluated together, the state (form) of the choroid and / or retina can be appropriately evaluated.

  In the ophthalmologic apparatus disclosed in this specification, the arithmetic device is measured by the pulse wave measurement means using the pulse wave measurement site, the propagation speed of the pulse wave, and the distance from the pulse wave measurement site to the fundus of the eye to be examined. The pulse wave may be corrected to the pulse wave in the fundus. According to such a configuration, the pulse wave in the fundus can be estimated more accurately, and the state of the choroid and / or retina can be more appropriately evaluated.

  In the ophthalmologic apparatus disclosed in this specification, the arithmetic unit may further measure the pulse wave using a Doppler signal obtained from the interference light received by the light receiving element. According to such a configuration, since the pulse wave at the position where the fundus tomographic image is acquired is measured, the state of the choroid and / or retina can be more appropriately evaluated.

  In the ophthalmologic apparatus disclosed in the present specification, the arithmetic device may further calculate the axial length of the eye to be examined from the interference light received by the light receiving element. According to such a configuration, the axial length and the state of the choroid and / or retina can be evaluated together, so that the state (form) of the choroid and / or retina can be appropriately evaluated.

  The ophthalmologic apparatus disclosed in the present specification may further include an intraocular pressure measurement device that measures the intraocular pressure of the eye to be examined. The intraocular pressure measurement device may measure intraocular pressure when repeatedly acquiring a plurality of fundus tomographic images. According to such a configuration, the intraocular pressure and the state of the choroid and / or retina can be evaluated together, so that the state (form) of the choroid and / or retina can be appropriately evaluated.

  The ophthalmologic apparatus disclosed in the present specification may further include a display that displays the dynamic change of the index output from the arithmetic device. According to such a configuration, since a dynamic change of an index representing at least one of the choroid and the retina is shown on the display, the state of the choroid and / or the retina can be grasped visually.

  For example, in the ophthalmologic apparatus disclosed in the present specification, the arithmetic device calculates the index at each position of the eye to be examined from a plurality of fundus tomographic images obtained by planarly scanning the light to be examined from the light source. Dynamic changes may be obtained. Then, the display device may display a two-dimensional map that displays each position of the eye to be examined and the dynamic change of the index at that position. According to such a configuration, since the state (morphology) at each position of the choroid and / or retina can be grasped, the state (morphology) of the choroid and / or retina can be appropriately evaluated.

  As shown in FIG. 1, an ophthalmologic apparatus 70 according to the present embodiment includes a tomographic image acquisition unit 10 that acquires a tomographic image of the eye E, an operation unit 58 that is operated by an operator, a monitor 60 that displays a tomographic image and the like, A control unit 50 that controls the tomographic image acquisition unit 10 is provided. The ophthalmologic apparatus 70 includes an anterior ocular segment observation unit that observes the anterior ocular segment of the eye E, an alignment unit that aligns the tomographic image acquisition unit 10 with respect to the E eye E in a predetermined positional relationship, and the like. doing. Since those used in known ophthalmic devices can be used, detailed description thereof is omitted.

  The tomographic image acquisition unit 10 has a function of capturing a tomographic image of the fundus oculi Er by irradiating light to the fundus oculi (fundus retina) Er of the eye E. This is an interference optical device that causes interference between the backscattered light from each tissue of the optometer E) and the reference light. As shown in FIG. 2, the tomographic image acquisition unit 10 includes a light source 12, a measurement optical system that irradiates the inside of the subject's eye with the light from the light source 12 and guides the measurement light from the subject's eye E, and Differential amplification detection that irradiates the reference surface and guides its reflected light, and receives interference light that combines the measurement light guided by the measurement optical system and the reference light guided by the reference optical system It is comprised with the container 40 (an example of the light receiving element as used in a claim).

  The light source 12 is a wavelength sweep type (wavelength scanning type) light source, and the wavelength of the emitted light changes at a predetermined cycle. In this embodiment, while changing the wavelength of the light emitted from the light source 12, the measurement light from the eye E and the reference light are caused to interfere with each other, and the interference light is measured. Then, by performing Fourier transform on the measured interference light (interference signal), it is possible to specify the position of each part (for example, crystalline lens, retina, choroid) in the eye E. The light source 12 is a light source that emits light having a wavelength of 1 μm band (for example, about 950 nm to 1100 nm). Light having a wavelength in the 1 μm band emitted from the light source 12 is strongly scattered by the living tissue and can reach deep into the living tissue. For this reason, the tomographic image of the deep part of the eye E to be examined can be acquired.

  The measurement optical system includes a polarization controller 14, an isolator 16, a first fiber coupler 18, a collimator lens 19, a galvanometer mirror unit 22, lenses 24 and 26, and a second fiber coupler 36. That is, the light output from the light source 12 is input to the polarization controller 14 and the isolator 16 through the optical fiber. The light output from the isolator 16 is input to the first fiber coupler 18 through the optical fiber, and is demultiplexed by the first fiber coupler 18. One of the lights demultiplexed by the first fiber coupler 18 is input to the galvanometer mirror unit 22 via the collimator lens 19. The galvanometer mirror unit 22 is a unit for scanning the light applied to the eye E and is driven by the galvano driver 20. The galvano mirror unit 22 is driven by the galvano driver 20 so that the light from the light source 12 is scanned in the horizontal direction and the vertical direction of the eye E. Light output from the galvanometer mirror unit 22 enters the eye E through the lens 24 and the objective lens 26. The light incident on the eye E is reflected and scattered by each part of the eye E (for example, each tissue part (retina, choroid, etc.) of the fundus Er). Measurement light from the eye E is input to the collimator lens 19 via the objective lens 26, the lens 24, and the galvanometer mirror unit 22. The measurement light output from the collimator lens 19 is received by the differential amplification detector 40 through the first fiber coupler 18 and the second fiber coupler 36.

  The reference optical system includes the first fiber coupler 18, the collimator lens 32, the delay line unit 28, the collimator lens 30, the polarization controller 34, and the second fiber coupler 36. That is, the light from the light source 12 is demultiplexed by the first fiber coupler 18. The other light demultiplexed by the first fiber coupler 18 (light not irradiated on the eye E) is input to the delay line unit 28 via the collimator lens 32. The delay line unit 28 is a unit for adjusting the optical path length that matches the reference optical path length with a desired part of the eye E (for example, on the retina of the fundus Er). The delay line unit 28 includes a reference surface to which light from the light source 12 is irradiated, and adjusts the optical path length of the reference light by adjusting the position of the reference surface. The light from the delay line unit 28 is received by the differential amplification detector 40 through the collimator lens 30, the polarization controller 34 and the second fiber coupler 36.

  The differential amplification detector 40 detects interference light obtained by combining light guided by the reference optical system (reference light) and light guided by the measurement optical system (measurement light). Specifically, backscattered light (measurement light) from each tissue of the eye E is guided to the second fiber coupler 36 by the measurement optical system, and light (reference light) from the delay line unit 28 is reference optics. It is guided to the second fiber coupler 36 by the system. These measurement light and reference light are combined in the second fiber coupler 36, and the interference light is detected by the differential amplification detector 40. The differential amplification detector 40 includes a photoelectric conversion element, converts the interference light into an electric signal, and outputs it. A signal output from the differential amplification detector 40 is input to the control unit 50 and processed.

  As illustrated in FIG. 1, the control unit 50 includes a calculation unit 54, a storage unit 52, and an A / D board 56. The calculation unit 54 is configured by a microcomputer (microprocessor) including a CPU, a ROM, a RAM, and the like. The tomographic image acquisition unit 10 is connected to the calculation unit 54 via the A / D board 56, and the operation unit 58 and the monitor 60 are connected. The calculation unit 54 controls each unit of the tomographic image acquisition unit 10 (for example, the light source 12, the galvano mirror unit 22, the delay line unit 28, etc.) according to the input of the operation unit 58, and the tomographic image acquisition unit 10 generates a tomographic image. Take a picture. A tomographic image acquired by the tomographic image acquisition unit 10 (specifically, a signal output from the differential amplification detector 40) is converted into a digital signal by the A / D board 56 and input to the calculation unit 54. The calculation unit 54 acquires a tomographic image by performing Fourier transform or the like on the signal input from the tomographic image acquisition unit 10, stores the acquired tomographic image in the storage unit 52, and displays it on the monitor 60. Further, the calculation unit 54 repeatedly acquires a fundus tomographic image at a set position of the eye E (for example, an arbitrary position specified by the operator), and each of a plurality of continuous fundus tomographic images at each of these positions. From this, an index indicating the form of the choroid (in this embodiment, the thickness of the choroid) is calculated, and the dynamic change is output. Details of the processing for outputting the dynamic change in the thickness of the choroid by the calculation unit 54 will be described later.

  Next, a procedure for measuring a dynamic change in the thickness of the choroid of the eye E using the ophthalmologic apparatus 70 of the present embodiment will be described. As shown in FIG. 4, first, the operator (inspector) operates the operation unit 58 to align the tomographic image acquisition unit 10 with respect to the eye E (S10). That is, the calculation unit 54 drives a position adjustment mechanism (not shown) according to the operation of the operation unit 58 by the operator. Thus, the position of the tomographic image acquisition unit 10 with respect to the eye E is adjusted so that the light from the light source 12 is irradiated to a desired position of the eye E. Further, the calculation unit 54 adjusts the delay line unit 28 of the tomographic image acquisition unit 10 to adjust the optical path length of the measurement light so that the measurement target region of the fundus oculi Er of the eye E falls within a predetermined acquisition range. The position of the zero point where the optical path length of the reference light matches is adjusted.

  Next, the calculation unit 54 controls the tomographic image acquisition unit 10 to start acquiring a tomographic image of the fundus oculi Er of the eye E (S12), processes the signal from the tomographic image acquisition unit 10 and performs fundus oculi acquisition A tomographic image is acquired (S14). That is, the calculation unit 54 operates the light source 12 and irradiates the fundus Er of the eye E with light from the light source 12. As described above, the frequency of the light emitted from the light source 12 changes periodically, and the beat frequency component of the interference wave generated by the interference between the measurement light and the reference light depends on the depth direction of the eye tissue to be examined. Therefore, when the frequency of the light from the light source 12 is changed by one period, the signal obtained by the tomographic image acquisition unit 10 is a portion of the fundus Er (for example, the retina 82, the retinal pigment epithelium 84, the choroid 86, The measurement light (backscattered light) from the film 88 and the like (see FIG. 3)) and the interference light by the reference light become a combined signal. For this reason, the calculation unit 54 performs Fourier transform on the signal input from the tomographic image acquisition unit 10, thereby obtaining signals from the respective parts of the fundus oculi Er (for example, the retina 82, the retinal pigment epithelium 84, the choroid 86, the sclera 88). The interference signal component due to the measurement light (backscattered light) is separated. Thereby, the calculating part 54 can pinpoint the position of each part (For example, the front surface and rear surface of the retina 82, the front surface and rear surface of the choroid 86, etc.) of the eye E to be examined. Note that the intensity distribution of the measurement light (backscattered light) from each part in the depth direction is obtained by Fourier-transforming the signal obtained by changing the frequency of the light emitted from the light source 12 by one period at the same position. Obtaining is referred to as A-scan in this specification.

  The calculation unit 54 drives the galvano mirror unit 22 in synchronization with changing the frequency of the light emitted from the light source 12, and the position of the light emitted from the light source 12 is set in one direction on the fundus Er. (In other words, the position of the light emitted from the light source 12 is linearly scanned on the fundus oculi Er). Thereby, at each point on the scanning line, the position of each part (retinal 82, retinal pigment epithelium 84, choroid 86, sclera 88) of the fundus Er at that point can be specified, and a fundus tomographic image of the fundus Er (FIG. 3). ) Is acquired. Here, the direction in which the galvanometer mirror unit 22 scans light can be set to an arbitrary direction by the calculation unit 54. Therefore, the calculation unit 54 can acquire a fundus tomographic image of a cross section in an arbitrary direction of the fundus oculi Er by setting the light scanning direction to an arbitrary direction. The light scanning direction set by the galvano mirror unit 22 is input from the calculation unit 54 to the galvano driver 20. The galvano driver 20 controls the galvanometer mirror unit 22 based on a command from the calculation unit 54. Thereby, a fundus tomographic image of the fundus oculi Er is acquired. Scanning the light from the light source 12 linearly is referred to as B-scan in this specification. Note that the period of scanning the light from the light source 12 is set to be shorter than the period of the pulse wave. Thereby, the change of the fundus oculi Er according to the pulse wave can be observed. The pulse wave cycle varies from person to person. For this reason, the period of scanning light from the light source 12 is set so as to be shorter than the period of the pulse wave with reference to the period of the pulse wave of a normal person.

  Further, the center position of the fundus tomographic image can be adjusted to an arbitrary position by adjusting the position of the tomographic image acquisition unit 10 with respect to the eye E to be examined. That is, in step S10, by adjusting the position of the tomographic image acquisition unit 10 with respect to the eye E to be examined, the position of the center of the fundus tomographic image can be set to an arbitrary position. In the fundus tomographic image shown in FIG. 3, the position of the retinal fovea 80 of the retina 82 is the center position of the fundus tomographic image.

  As described above, when the tomographic image is acquired in step S14, the calculation unit 54 stores the fundus tomographic image acquired in step S14 in the storage unit 52 (S16). Next, the calculation unit 54 determines whether or not a predetermined number of fundus tomographic images have been acquired (S18). If the set number of fundus tomographic images has not been acquired (NO in step S18), the calculation unit 54 returns to step S12 and repeats the processing from step S12. Thereby, the fundus tomographic image at the same position of the eye E is repeatedly acquired.

  On the other hand, when the set number of fundus tomographic images have been acquired (YES in step S18), the calculation unit 54 calculates the layer thickness T of the choroid 86 from each fundus tomographic image stored in step S16, respectively. A dynamic change in the layer thickness T of the choroid 86 (that is, an index representing the form of the choroid 86) is calculated (S20). That is, the storage unit 52 stores a plurality of fundus tomographic images that are repeatedly acquired in chronological order. For this reason, the dynamic change of the layer thickness T of the choroid 86 can be calculated by calculating the layer thickness T of the choroid 86 from each fundus tomographic image.

  The layer thickness T of the choroid 86 can be calculated by specifying the position of the boundary between the retinal pigment epithelium 84 and the choroid 86 and the position of the boundary between the choroid 86 and the sclera 88. The position of the boundary between the retinal pigment epithelium 84 and the choroid 86 and the position of the boundary between the choroid 86 and the sclera 88 can be specified using a known image processing technique. For example, the positions of these boundaries may be specified from the change in luminance in the fundus tomographic image. Further, the position at which the layer thickness T of the choroid 86 is measured can be, for example, a position away from the retinal fovea 80 that is the center of the fundus by a predetermined distance in a predetermined direction. Alternatively, the layer thickness T of the choroid 86 may be calculated at a position away from the optic disc by a predetermined distance in a predetermined direction with the optic disc as a reference. Furthermore, the layer thickness T of the choroid 86 may be calculated at a plurality of positions.

  When the dynamic change of the layer thickness T of the choroid 86 is calculated in step S20, the calculation unit 54 displays the calculated dynamic change of the layer thickness T of the choroid 86 on the monitor 60 (S22). Thus, the operator (inspector) can visually confirm the dynamic change in the layer thickness T of the choroid 86. The change in the parameter such as the layer thickness T may be displayed on a two-dimensional moving image composed of a plurality of fundus tomographic images. According to such a configuration, the change of the parameter and the change of the fundus tomographic image can be visually confirmed simultaneously.

  As apparent from the above description, in the ophthalmologic apparatus 70 according to the present embodiment, the fundus tomographic image is repeatedly acquired at the same position of the fundus oculi Er of the eye E, and the layer thickness T of the choroid 86 is obtained from the plurality of fundus tomographic images. The dynamic change of is output. For this reason, even if the amount of blood flowing through the blood vessels in the choroid 86 changes and the layer thickness T of the choroid 86 changes, the change can be confirmed. Therefore, the state of the choroid 86 can be properly diagnosed, and the relationship between various fundus diseases such as glaucoma and ocular circulation can be appropriately diagnosed.

  Although the present embodiment has been described in detail above, this is merely an example and does not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  For example, in the ophthalmologic apparatus of the above-described embodiment, the state (form) of the choroid is diagnosed. However, the present invention is not limited to such an example, and the state of the retina may be diagnosed, and the state of the retina and the choroid may be diagnosed. Also good. For example, when diagnosing the state of the retina, a dynamic change in an index representing the shape of the retina (for example, the layer thickness of the retina) may be output. Further, when diagnosing the state of the retina and choroid, dynamic changes of both the index representing the retina morphology and the index representing the choroid morphology may be output.

  In the above-described embodiments, the layer thickness T of the choroid 86 is used as an index representing the form of the choroid 86. However, other indices can be used as the index representing the form of the choroid 86. For example, the blood vessel cross-sectional area and / or blood vessel diameter of the choroid 86 can be used as an index. The blood vessel cross-sectional area and / or the blood vessel diameter of the choroid 86 has a direct correlation with the blood flow amount flowing through the blood vessel in the choroid 86, and the state of the choroid 86 can be appropriately evaluated. Further, since the layer thickness of the retina 82 also changes due to the change in the layer thickness T of the choroid 86 and the retinal blood flow, the layer thickness of the retina 82 is an index that is affected by the ocular circulation. It is good also as a parameter | index showing a form. The retina 82 is located on the surface side of the eye E with respect to the choroid 86. Therefore, the retina 82 can be detected more clearly than the choroid 86, and its layer thickness can be easily detected. The sum of the thickness of the choroid 86 and the thickness of the retina 82 may be used as an index representing the form of the choroid 86. Alternatively, the blood vessel cross-sectional area and / or blood vessel diameter of the retina 82 may be used as an index. Further, the thickness of the sieve plate, the nipple diameter, the nipple depression diameter, the depression nipple ratio (C / D ratio), the distance (diameter) connecting the bluff film end in the nipple, and the area formed by the bluff film end ( Bruch's membrane opening (BMO)) may be used as an index. In addition, as an index representing the form of the choroid 86 and / or the retina 82, not only one parameter but also a plurality of parameters may be used.

  Further, the method for specifying the index is not limited to the method of the above-described embodiment, and various methods can be used. For example, an index can be specified using local correlation used in the field of image processing. In this case, using one fundus tomographic image selected from a plurality of fundus tomographic images acquired repeatedly as a reference image, a local correlation with other fundus tomographic images may be calculated, thereby identifying an index. . For example, a fundus tomographic image acquired at a certain time is acquired at another time using a partial image including a boundary between layers determined by a known method (for example, a general boundary extraction method or a manual trace). The position where the local correlation with the partial image is highest in the fundus tomographic image may be used as the boundary line between the layers.

  In addition, in order to specify the above-described index, birefringence information of light irradiated on the eye E may be used. That is, the light irradiated to the eye E has different birefringence depending on the orientation structure of collagen fibers in each tissue of the fundus Er. Therefore, the tissue can be discriminated from the difference in intensity (magnitude) of the obtained birefringence. For this reason, the retina, choroid, and sclera may be discriminated from the difference in birefringence, and the thickness of the portion corresponding to the choroid or retina may be measured.

  Furthermore, in order to specify the above-mentioned index, a segmentation technique for extracting the contour of the object may be used. By using the segmentation technique, the contour (boundary line) of each layer can be extracted from the fundus tomographic image, and thereby the layer thickness T of the choroid 86 can be calculated. Note that when a segmentation technique is used, a learning algorithm may be used. Examples of the learning type algorithm include a neural network, a genetic algorithm, and a random forest method. As a specific method, for example, a plurality of sets of correct outputs (contour lines of each layer) corresponding to one or a plurality of input information (for example, luminance information of a fundus tomographic image, Doppler signal, birefringence information, etc.) are prepared. Then, a function of the system is generated by learning. Then, by giving input information obtained from an image whose contour is to be determined to a system that has completed learning, the contour of the image is output.

  Furthermore, an index representing the form of the choroid 86 (for example, the blood vessel cross-sectional area of the choroid 86) may be calculated using the Doppler signal obtained by the tomographic image acquisition unit 10. That is, as shown in FIG. 5, when the blood vessel is irradiated with light from the light source 12, the differential amplification detector 40 takes time from the first interference signal (the upper signal in FIG. 5) and the first interference signal by ΔT. The second interference signal (the lower signal in FIG. 5) causing the delay is detected, and the shift amount Δφ of the phase component for each frequency of the two interference signals is imaged, whereby the blood flow of the choroid 86 is reduced. Can be identified. Specifically, when the phase shift amount Δφ is imaged as shown in FIG. 6, the blood vessel cross-sectional area of the choroid 86 can be specified. Since the blood flow velocity Vz is obtained from the phase shift amount Δφ and the time difference Δt, the blood flow amount can be calculated from the specified blood vessel cross-sectional area and the blood flow velocity Vz.

  In addition, various methods can be used to calculate the position of the choroid 86 (the position of the front surface and the position of the back surface). Further, the position of the choroid 86 may be calculated using the entire fundus tomographic image as a calculation target, or the position of the choroid 86 may be calculated from a portion obtained by dividing a specific region from the fundus tomographic image. Furthermore, the calculation area may be limited using the luminance information of the fundus tissue obtained by the segmentation, the calculation area may be limited using the above-described Doppler signal, or the birefringence information of the reflected light May be used to limit the calculation area. For example, an artery is identified from the Doppler signal, and the morphological change in the artery diameter and cross-sectional area may be captured. Since pulsations appear in arteries compared to veins, morphological changes associated with ocular circulation can be captured effectively.

Further, a pulse wave measuring unit may be provided in the ophthalmologic apparatus so that the pulse wave is measured simultaneously with the repeated acquisition of the fundus tomographic image. According to such a configuration, it is possible to accurately grasp the relationship between the change in the layer thickness of the choroid 86 and the pulse wave. The pulse wave can be measured using a pulse wave meter or a pulse oximeter. Further, the pulse wave may be detected by the above-described Doppler signal. That is, a periodic change of the blood vessel diameter may be acquired from the Doppler signal, and the pulse wave may be detected from the periodic change. If the blood vessel diameter of the choroid 86 is acquired from the Doppler signal, the pulse wave in the choroid 86 can be directly acquired, so that the state of the choroid 86 can be diagnosed more appropriately. Furthermore, the pulse time difference due to the difference between the measurement position of the pulse wave and the position of the choroid 86 may be corrected. For example, it may be corrected by a Doppler signal, or the pulse wave of the subject is detected at a plurality of positions (for example, the carotid artery and wrist, the carotid artery and ankle, the eyelid and the earlobe, etc.), and the pulse wave velocity is determined from the detection results. The time difference may be corrected from the pulse wave velocity. For example, assuming that the distance between the carotid artery and the wrist is Lb and the time difference between the pulse waves measured at the two locations is the pulse wave propagation time PtTb, the pulse wave propagation velocity PWV is calculated by the following calculation formula.
PWV = Lb / PtTb
Here, when the distance from the carotid artery to the fundus is Le, the time PtTe in which the pulse wave propagates from the carotid artery to the fundus can be obtained by the following calculation formula.
PtTe = Le / PWV
Therefore, if the phase is delayed by the propagation time PtTe to the fundus with respect to the pulse wave in the carotid artery, the pulse wave in the fundus can be obtained.

  When detecting a pulse wave, the layer thickness T of the choroid 86 and the pulse wave may be displayed together on the monitor 60 as a graph. That is, as shown in FIG. 7, when the pulse wave (lower graph) and the layer thickness T (upper graph) of the choroid 86 are shown together on the monitor 60, the choroid 86 changes in response to changes in the pulse wave. The operator (inspector) can grasp at a glance that the layer thickness T has changed. The graph display can be performed in various modes. For example, as shown in FIG. 8, the result of frequency analysis of the pulse wave and the layer thickness T of the choroid may be displayed on the monitor 60.

  Furthermore, the ophthalmologic apparatus of the above embodiment may further measure the axial length and intraocular pressure of the eye to be examined. By measuring the state of the choroid 86 together with the axial length and / or intraocular pressure, the state of the eye E can be comprehensively determined.

  In the above-described embodiment, the ophthalmologic apparatus includes the Fourier domain tomographic image acquisition unit 10. However, the ophthalmologic apparatus may include a time domain tomographic image acquisition unit. Further, the light from the light source 12 may be planarly scanned with the fundus oculi Er to acquire a three-dimensional fundus tomographic image, and an index representing the form of the choroid 86 may be acquired two-dimensionally. According to such a configuration, the state of the choroid 86 of the eye E can be diagnosed more precisely. Furthermore, when the index is acquired two-dimensionally, the degree of dynamic change (change rate) of the index may be displayed as a single map. For example, the layer thickness or blood vessel amplitude, change rate, phase, etc. are displayed in a two-dimensional color map. In addition, the map obtained on the two-dimensional image of the photographed fundus is displayed so that the relationship between the index and the fundus structure (for example, the position of the optic nerve head or the diseased part) can be confirmed at a glance. May be.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

DESCRIPTION OF SYMBOLS 10 Tomographic image acquisition part 12 Light source 18 1st fiber coupler 22 Galvano mirror unit 28 Delay line unit 36 2nd fiber coupler 54 Calculation part

Claims (12)

A light source;
A measurement optical system that irradiates the inside of the eye with light from the light source and guides the measurement light from the inside of the eye;
A reference optical system that irradiates the reference surface with light from the light source and guides the reflected light; and
A light receiving element for receiving interference light in which measurement light guided by the measurement optical system and reflected light guided by the reference optical system are combined;
Dynamics of indices representing at least one form of the choroid and retina based on a plurality of fundus tomographic images at a set position inside the eye to be examined, which are repeatedly acquired from the interference light received by the light receiving element at a cycle shorter than the pulse wave An ophthalmologic apparatus comprising: an arithmetic device that outputs a change.   The index is at least one of a choroid layer thickness, a retina layer thickness, at least one blood vessel diameter of the choroid and retina, and a cross-sectional area of blood vessels of at least one of the choroid and retina specified from the fundus tomographic image. The ophthalmic apparatus according to claim 1.   The ophthalmologic apparatus according to claim 1, wherein the arithmetic device outputs a dynamic change of the index using a whole or a partial region of the fundus tomographic image.   The ophthalmologic apparatus according to claim 3, wherein the arithmetic device determines a region of a fundus tomographic image to be used when outputting a dynamic change of the index using a Doppler signal obtained from interference light received by a light receiving element. . It further comprises a pulse wave measuring means for measuring the pulse wave,
The ophthalmologic apparatus according to any one of claims 1 to 4, wherein the pulse wave measurement unit measures a pulse wave when repeatedly acquiring a plurality of fundus tomographic images.   The arithmetic unit corrects the pulse wave measured by the pulse wave measuring means to the pulse wave on the fundus using the pulse wave measurement site, the propagation speed of the pulse wave, and the distance from the pulse wave measurement site to the fundus of the eye to be examined. The ophthalmic apparatus according to claim 5.   5. The ophthalmologic apparatus according to claim 1, wherein the arithmetic device further measures a pulse wave using a Doppler signal obtained from interference light received by the light receiving element.   The ophthalmologic apparatus according to any one of claims 1 to 7, wherein the arithmetic device further calculates the axial length of the eye to be examined from the interference light received by the light receiving element. It further comprises an intraocular pressure measuring device that measures the intraocular pressure of the eye to be examined,
The ophthalmic apparatus according to any one of claims 1 to 8, wherein the intraocular pressure measurement apparatus measures intraocular pressure when repeatedly acquiring a plurality of fundus tomographic images.   10. The ophthalmologic apparatus according to claim 1, wherein the arithmetic device has a frequency analysis function or a waveform analysis function with respect to a dynamic change of the index.   The ophthalmologic apparatus according to claim 1, further comprising a display that displays a dynamic change of the index output from the arithmetic device. The arithmetic device acquires a dynamic change of the index at each position of the eye to be examined from a plurality of fundus tomographic images obtained by scanning light from the light source with respect to the eye to be examined,
The ophthalmologic apparatus according to claim 11, wherein the display unit displays a two-dimensional map that displays each position of the eye to be examined and a dynamic change of the index at the position.

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