JP2019136567A - Eyeground analysis apparatus - Google Patents

Abstract

To provide an eyeground analysis apparatus capable of stably analyzing an eyeground while reducing a burden on a subject.SOLUTION: The eyeground analysis apparatus comprises an analysis unit and a distribution information generating unit. The analysis unit analyzes time-series data of the eyeground of a subject eye to thereby determine time-series variation in reaction of photoreceptors to light stimulation. The distribution information generating unit generates photoreceptor distribution information on the basis of the time-series variation. The distribution information includes the total number of photoreceptors, the numbers of photoreceptors by type, and a ratio of the number of type-1 photoreceptors to the number of type-2 photoreceptors or a determination result about the total number of photoreceptors or the number of photoreceptors by type with respect to a predetermined reference value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fundus analysis apparatus.

  A plurality of photoreceptor cells are arranged in the retina. Light incident on the eye is converted into an electrical signal by the photoreceptor cell, and then transmitted from the ganglion cell located near the surface of the retina to the cerebrum via the optic nerve. There are cones and rods that are activated in different environments. There are three types of cones (L cone, M cone, and S cone) having different wavelength sensitivities. The visual function can be examined by examining the function of the retina.

  One technique for examining retinal function is to evaluate cone distribution. For example, a technique is known in which the cone ratio between the number of L cones and the number of M cones is evaluated by flicker photometric ERG (flicker photometric electroretinogram) (Non-patent Document 1). Further, a method for evaluating the cone ratio with an adaptive optical fundus microscope using a flash light source is known (Non-Patent Document 2).

Heidi Hoffer, Joseph Carroll, Jay Neitz, Maureen Neitz, and David R., et al. Williams, “Organization of the Human Trichromatic Cone Mosaic”, The Journal of Neuroscience, Octer 19, 2005, pp. 9669-9679 Austin Rooda, and David R. Williams, “The arrangement of the three cones in the living human eye”, Nature, VOL 397, February 11, 1999, pp. 199-201. 520-522

  However, the flicker photometric ERG method is a contact type, and this method requires a long measurement time of about 1 hour each time. In the method using a flash light source, it is necessary to perform measurement every day for, for example, five days or more in order to improve the S / N ratio. Accordingly, there is a problem that any of the above methods increases the burden on the subject.

  In addition, the flicker photometry ERG method increases the measurement time, and thus the measurement results vary greatly. In the method using a flash light source, it is very difficult to measure the same part every day due to eye movement or the like. Therefore, any of the above methods has a problem that measurement becomes unstable and it is difficult to stably analyze the fundus.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a fundus analyzer that can reduce the burden on the subject and can stably analyze the fundus. There is to do.

  The fundus analysis apparatus according to the embodiment includes an analysis unit and a distribution information generation unit. An analysis part calculates | requires the time series change of the response of the photoreceptor with respect to optical stimulation by analyzing the time series data of the fundus of the eye to be examined. The distribution information generation unit generates photoreceptor distribution information based on a time-series change. Distribution information is based on the number of all photoreceptors, the number of each type of photoreceptor, the ratio of the number of the second type of photoreceptor to the number of the first type of photoreceptor, or a predetermined reference value Information indicating the determination result for the number of all photoreceptors or the number of photoreceptors for each type.

  According to the embodiment, it is possible to provide a fundus analysis apparatus that can reduce the burden on the subject and can stably analyze the fundus.

It is the schematic which shows an example of a structure of the optical system of the fundus analyzer which concerns on embodiment. It is the schematic which shows an example of a structure of the processing system of the fundus analyzer which concerns on embodiment. It is a flowchart of the operation example of the fundus analysis apparatus concerning an embodiment. It is explanatory drawing of the wavelength sensitivity of a photoreceptor. It is operation | movement explanatory drawing of the fundus analysis apparatus which concerns on embodiment. It is operation | movement explanatory drawing of the fundus analysis apparatus which concerns on embodiment. It is operation | movement explanatory drawing of the fundus analysis apparatus which concerns on embodiment.

  An example of an embodiment of a fundus analysis apparatus according to the present invention will be described in detail with reference to the drawings. In addition, it is possible to use the description content of the literature referred in this specification, and arbitrary well-known techniques for the following embodiment.

  The fundus analysis device analyzes the time series data of the fundus from before the retinal bleaching reaction to the light stimulus until after the reaction (or during or during the reaction). A time-series change in the reaction of the receptor can be obtained, and the photoreceptor can be specified based on this time-series change. A fundus analysis apparatus according to an embodiment includes an irradiation system that irradiates light for light stimulation to the fundus of a subject's eye and an optical system of a scanning laser ophthalmoscope, and a photoreceptor from a time-series image of the fundus Distribution information can be generated.

[Optical system]
FIG. 1 shows a configuration example of an optical system of a fundus analysis apparatus according to the embodiment. In FIG. 1, a position optically conjugate with the fundus oculi Ef of the eye E is shown as a fundus conjugate position P, and a position optically conjugate with the pupil of the eye E is shown as a pupil conjugate position Q.

  The optical system 100 includes a first irradiation system 110, a light guide system 120, a first detection system 140, a second detection system 150, a third detection system 160, an anterior ocular segment illumination system 170, and a fixation system. 180 and a second irradiation system 190.

(First irradiation system)
The first irradiation system 110 includes an optical system for irradiating the eye E with light. The light source 111 is a light source for fundus illumination, and is preferably a light source that emits light having a wide wavelength range. For example, a light source 111 that emits light having a center wavelength of 840 nm is used. Examples of the light source 111 include a laser diode (hereinafter, LD), a super luminescent diode (SLD), a laser driven light source (LDLS), and the like. The light source 111 is disposed at or near a position (fundus conjugate position) P optically conjugate with the fundus (retina).

  An optical fiber 112 that guides light to the light guide system 120 is connected to the light source 111. The optical fiber 112 is a single mode fiber. The exit end face of the optical fiber 112 is disposed at or near the fundus conjugate position P. A lens 113 for converting the light emitted from the optical fiber 112 into a parallel light beam is disposed at the output end of the optical fiber 112. The light that has passed through the lens 113 passes through the aperture of the diaphragm 114 and the lens 115 and is guided to the beam splitter 116. The diaphragm 114 is used to limit the amount of light from the light source 111.

  The beam splitter 116 is an optical path separation member that separates the optical path of the first detection system 140 from the optical path of the first irradiation system 110. The beam splitter 116 transmits the light that has passed through the lens 115 and guides it to the beam splitter 121, and reflects the fundus reflection light from the eye E toward the first detection system 140. As the beam splitter 116, for example, a polarization beam splitter is used.

(Light guide system)
The light guide system 120 includes an optical system that guides light from the first irradiation system 110 to the eye E and guides reflected light from the eye E to the first detection system 140 and the second detection system 150. Yes. The beam splitter 121 is an optical path dividing member that divides the optical path of the light guide system 120 into the optical path of the first irradiation system 110 and the optical path of the second detection system 150. The beam splitter 121 reflects the light transmitted through the beam splitter 116 toward the wavefront correction element 122 and transmits the fundus reflection light from the eye E to be guided to the condenser lens 153. As the beam splitter 121, for example, a beam splitter having a characteristic that the reflectance is 10% and the transmittance is 90% is used.

  The wavefront correction element 122 is an element that is deformed so as to correct aberration based on a detection result of a first detection system 140 described later. For the wavefront correction element 122, for example, a deformable mirror is used. The deformable mirror is a deformable mirror for performing wavefront correction. The deformable mirror is a mirror that can deform the surface shape by a plurality of actuators. The reflection surface of the wavefront correction element 122 is disposed at a position (pupil conjugate position) Q that is optically conjugate with the pupil of the eye E to be examined and the detection surface of the lens array 143 of the first detection system 140 or in the vicinity thereof. A liquid crystal spatial modulator may be used for the wavefront correction element 122.

  An optical scanner 125 is disposed on the eye E side of the wavefront correction element 122 via a lens system 124 for adjusting the light flux. The optical scanner 125 is used to scan the fundus oculi Ef of the eye E with the light from the light source 111. The optical scanner 125 includes a vertical optical scanner 125V and a horizontal optical scanner 125H. The vertical optical scanner 125V is a mirror whose tilt can be changed, and the tilt of the reflection surface is controlled by the control unit 200 described later. The vertical direction optical scanner 125V is used for, for example, scanning in the vertical direction within the fundus. The vertical direction optical scanner 125V may be a low speed scanner such as a galvanometer mirror. On the eye E side of the vertical optical scanner 125V, a horizontal optical scanner 125H is arranged via a lens system 126. The horizontal optical scanner 125H is a mirror whose tilt can be changed, and the tilt of the reflecting surface is controlled by the control unit 200. The horizontal optical scanner 125H is used for, for example, scanning in the horizontal direction within the fundus oculi orthogonal to the vertical direction. One of the vertical direction optical scanner 125V and the horizontal direction optical scanner 125H may be a high-speed scanner such as a resonant mirror or a MEMS (Micro Electro Mechanical Systems) mirror. The reflecting surface of the vertical direction optical scanner 125V and the reflecting surface of the horizontal direction optical scanner 125H are disposed at a position (pupil conjugate position) Q or a vicinity thereof that is optically conjugate with the pupil of the eye E.

  A diopter correction mechanism 128 is disposed on the eye E side of the horizontal optical scanner 125H via a lens 127. The diopter correction mechanism 128 is an example of an adjustment unit for adjusting the light so as to irradiate the fundus oculi Ef as a substantially point image. The diopter correction mechanism 128 continuously moves the position of the fundus conjugate point according to the refractive power of the eye E. Thereby, the fundus oculi Ef, the pinhole 152 described later, and the emission end face of the optical fiber 112 are arranged at the conjugate position. The diopter correction mechanism 128 includes V-shaped diopter correction mirrors 129 and 130. By adjusting the diopter correction mirror 130 relative to the diopter correction mirror 129, the diopter correction mirror 130 is adjusted so that the focal point of the optical system 100 is positioned on the fundus oculi Ef. That is, there are individual differences and individual differences in diopter, but even if there is a difference in diopter, the focus of the optical system 100 is positioned on the fundus oculi Ef by moving the position of the diopter correction mirror 130. That is, adjustment is made so that the irradiation light is condensed and irradiated as a substantially point image on the fundus oculi Ef. In the diopter correction mechanism 128, the pupil of the eye E to be examined has a conjugate relationship with infinity, so the pupil conjugate relationship in the optical system 100 does not change due to the movement of the diopter correction mirror 130.

  Beam splitters 132 and 133 are disposed on the eye E side of the diopter correction mechanism 128 via the lens system 131. The beam splitter 132 is an optical path separation member that separates the optical path of the third detection system 160 from the optical path of the light guide system 120. The beam splitter 132 is a dichroic mirror that separates, for example, light from the light source 111 and light from an anterior ocular segment illumination system 170 described later. For example, the beam splitter 132 has a characteristic of transmitting light having a center wavelength of 950 nm and reflecting light having a center wavelength of 840 nm. The beam splitter 133 is a dichroic mirror that couples the optical path of the fixation system 180 and the optical path of the second irradiation system 190 to the optical path of the light guide system 120, for example. The beam splitter 133 has a characteristic of transmitting light having a center wavelength of 400 nm to 600 nm and reflecting light having center wavelengths of 840 nm and 950 nm, for example.

  An objective lens 134 is disposed on the eye E side of the beam splitter 133. The objective lens 134 has a structure in which a plurality of lenses are combined in order to suppress aberrations (of course, it may be composed of a single lens).

(First detection system)
The first detection system (wavefront detection system) 140 includes an optical system for detecting the wavefront of the fundus reflection light from the eye E. The first detection system 140 includes a wavefront detection unit 141 and a pair of lenses 144. The wavefront detection unit 141 is a Shack-Hartmann sensor including a Hartmann imaging device 142 and a lens array 143 arranged in front of the Hartmann imaging device 142. The Hartmann imaging device 142 is disposed at the focal position of the lens array 143 and captures a point image formed by the lens array 143. The Hartmann imaging device 142 is a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor. The lens array 143 is an array of small lenses arranged in a lattice pattern, and divides incident light into a number of light beams (for example, 16 light beams) and condenses them. By picking up the focal point of the lens array 143 with the Hartmann imaging device 142 and analyzing the focal position of each lens, the wavefront aberration of the light incident on the lens array 143 can be detected. That is, by observing a reflected image from the fundus oculi Ef of the eye E through the lens array 143, it is possible to detect the wavefront disturbance in the reflected image. An image obtained by the Hartmann imaging device 142 is sent to an image analysis unit such as a control unit 200 described later, where wavefront disturbance is analyzed by this image analysis unit, and a control signal (feedback signal) based on the result is converted into a wavefront. It is sent to the correction element 122. A confocal stop may be disposed at the fundus conjugate position P between the pair of lenses 144.

(Second detection system)
The second detection system (fundus reflected light detection system) 150 includes an optical system for detecting reflected light from the fundus oculi Ef of the eye E to be examined. The second detection system 150 includes a light receiver 151, a pinhole 152, and a condenser lens 153. The light transmitted through the beam splitter 121 is condensed on the detection surface of the light receiver 151 by the condenser lens 153. The pinhole 152 is movable in the optical axis direction, and is moved so that the hole is disposed at the fundus conjugate position P. The detection surface of the light receiver 151 may be disposed in the vicinity of the fundus conjugate position P. The light receiver 151 includes, for example, an avalanche photodiode (APD) or a photomultiplier tube (PMT).

(Third detection system, anterior segment illumination system)
The anterior segment illumination system 170 includes a light source for illuminating the anterior segment of the eye E. The third detection system (anterior segment reflected light detection system) 160 includes an optical system for detecting the reflected light from the anterior segment of the eye E illuminated by the anterior segment illumination system 170. For the anterior segment illumination system 170, for example, an LED that emits light having a center wavelength of 950 nm is used. The third detection system 160 includes a lens 161 and an anterior segment imaging device 162. The light that has passed through the beam splitter 132 is condensed on the detection surface of the anterior segment imaging element 162 by the lens 161. The detection surface of the anterior segment imaging element 162 is disposed at or near the pupil conjugate position Q. The anterior segment imaging element 162 is configured by, for example, a CCD or CMOS image sensor. The detection result of the reflected light from the anterior segment of the eye E to be examined by the anterior segment imaging element 162 is used to form an anterior segment image.

(Fixation system)
The fixation system 180 includes an optical system for fixing the eye E to be examined. The fixation system 180 includes a diopter adjustment lens 181, a beam splitter 182, and a fixation target 183. The diopter adjustment lens 181 is a lens that can move in the optical axis direction according to the refractive index of the eye E to be examined. The diopter adjustment lens 181 is moved so that the fundus oculi Ef and the fixation target 183 are in an optically conjugate position. The beam splitter 182 is an optical path coupling member that couples the optical path of the second irradiation system 190 to the optical path of the fixation system 180. For the beam splitter 182, for example, a half mirror having a reflectance of 50% and a transmittance of 50% is used. The beam splitter 182 may have a mirror formed on a part of the light reflection surface. The fixation target 183 projects an index for fixing the eye E to the fundus oculi Ef of the eye E with light having a central wavelength of 400 nm to 700 nm, for example. For the fixation target 183, for example, a film, an organic EL, an LCD, or the like is used. The beam splitter 182 transmits the light from the fixation target 183 and guides it to the beam splitter 133, and reflects the light from the second irradiation system 190 toward the beam splitter 133.

(Second irradiation system)
The second irradiation system (irradiation system, light stimulation system) 190 includes an optical system for irradiating the fundus oculi Ef of the eye E with a predetermined wavelength. The second irradiation system 190 includes a field stop 191, an aperture stop 192, a lens 193, a wavelength selection filter 194, a lens 195, and a bleaching light source 196. The bleaching light source 196 is a light source for irradiating the eye E with stimulation light. As the bleaching light source 196, for example, a halogen lamp or a xenon lamp is used. The lens 195 turns the light from the bleaching light source 196 into a parallel light beam. The wavelength selection filter 194 transmits light having a predetermined wavelength out of the light from the bleaching light source 196. As the wavelength selection filter 194, for example, a bandpass filter having a characteristic of transmitting light having a center wavelength of 650 nm and reflecting other wavelength components is used. The lens 193 collects the light that has passed through the wavelength selection filter 194. The aperture stop 192 is used to adjust the amount of light that has passed through the lens 193. The field stop 191 is used to limit the range in which the fundus oculi Ef of the light that has passed through the aperture stop 192 is illuminated.

  In the above configuration, the light from the first irradiation system 110 is guided to the eye E by the light guide system 120. The fundus reflection light from the eye E travels in the opposite direction of the light path from the objective lens 134 to the beam splitter 121, a part is reflected toward the beam splitter 116, and the rest passes through the beam splitter 121. . The fundus oculi reflection light reflected by the beam splitter 121 is guided to the first detection system 140 by the beam splitter 116. The first detection system 140 detects the reflected image from the fundus oculi Ef of the eye E through the lens array 143. The control unit 200 (or data processing unit 220) described later analyzes wavefront disturbance based on the detection result of the first detection system 140 as an image analysis unit. The wavefront correction element 122 is deformed so as to correct the aberration based on the analysis result. On the other hand, the fundus reflection light transmitted through the beam splitter 121 is condensed on the detection surface of the light receiver 151 by the condenser lens 153. The detection result of the fundus reflection light by the light receiver 151 is used to form an SLO (Scanning Laser Ophthalmoscope) image (near infrared image) as a detection result of light at the fundus conjugate point.

  The reflected light from the eye E illuminated by the anterior segment illumination system 170 passes through the beam splitter 132 and is collected on the detection surface of the anterior segment imaging element 162 by the lens 161. The detection result of the reflected light from the anterior segment of the eye E to be examined by the anterior segment imaging element 162 is used to form an anterior segment image.

[Processing system]
FIG. 2 shows a configuration example of a processing system of the fundus analysis apparatus according to the embodiment. In FIG. 2, the same parts as those in FIG.

(Control part)
The processing system of the fundus analysis device according to the embodiment is configured around the control unit 200. The control unit 200 controls each unit of the fundus analysis apparatus. The control unit 200 includes a main control unit 201 and a storage unit 202. The main control unit 201 includes a display control unit 201A. The function of the main control unit 201 is realized by a microprocessor, for example. The storage unit 202 stores in advance a computer program for controlling the fundus analysis apparatus. This computer program includes various light source control programs, diopter correction mechanism control programs, optical scanner control programs, various detection system control programs, image formation programs, data processing programs, display control programs, and Includes user interface programs. When the main control unit 201 operates according to such a computer program, the control unit 200 executes control processing.

  Control for the first irradiation system 110 includes control of the light source 111 and control of the diaphragm 114. Control of the light source 111 includes turning on and off the light source, adjusting the light amount, and the like.

  Controls for the light guide system 120 include control of the wavefront correction element 122, control of the optical scanner 125, control of the diopter correction mechanism 128, and the like. When the wavefront correction element 122 includes a deformable mirror, the control of the wavefront correction element 122 includes control of driving a plurality of actuators based on the analysis result of the image formed using the detection result of the Hartmann imaging element 142. . For example, when there is distortion (wavefront distortion) in the captured image based on the detection result of the Hartmann imaging device 142, the surface shape of the deformable mirror is deformed so as to reduce the distortion. That is, the surface shape of the deformable mirror is deformed by feedback control so that distortion of the image of the fundus oculi Ef based on the detection result of the first detection system 140 is reduced, and distortion of the image of the fundus oculi Ef is suppressed. . Control of the optical scanner 125 includes control of the scanning position and scanning range by the vertical direction optical scanner 125V, and control of the scanning position and scanning range by the horizontal direction optical scanner 125H. Control of the diopter correction mechanism 128 includes control of a mechanism driving unit corresponding to the diopter. The mechanism driving unit moves the diopter correction mechanism 128.

  Controls for the first detection system 140 include exposure adjustment, gain adjustment, and imaging rate adjustment of the Hartmann imaging device 142.

  Control for the second detection system 150 includes control of a drive unit that moves the pinhole 152 in the optical axis direction, exposure adjustment, gain adjustment, and photographing rate adjustment of the light receiver 151.

  Controls for the third detection system 160 include exposure adjustment, gain adjustment, and imaging rate adjustment of the anterior segment imaging element 162. Controls for the anterior segment illumination system 170 include turning on and off the anterior segment illumination light source, adjusting the amount of light, and adjusting the aperture.

  Control for the fixation system 180 includes changing the position of the index on the fixation target 183 and switching the index.

  As control for the second irradiation system 190, adjustment of the illumination range by the field stop 191; adjustment of the amount of light by the aperture stop 192; change of wavelength selection characteristics by the wavelength selection filter 194; turning on and off of the bleaching light source 196; There is.

  The display control unit 201A displays various information on the UI unit 230 described later. The information displayed on the UI unit 230 includes information generated by the control unit 200, an image formed by the image forming unit 210, information after data processing by the data processing unit 220, and the like.

(Image forming part)
The image forming unit 210 forms a time-series image based on the detection result of the fundus reflection light by the light receiver 151. For example, the image forming unit 210 forms time-series image data based on the light reception signal input from the light receiver 151 and the pixel position signal input from the control unit 200. Time-series images include moving images and a plurality of still image groups formed with a predetermined time. Further, the image forming unit 210 forms an anterior ocular segment image based on the detection result of the reflected light from the anterior segment of the eye E to be examined by the anterior segment imaging element 162. Various images (image data) formed by the image forming unit 210 are stored in the storage unit 202, for example.

(Data processing part)
The data processing unit 220 executes various data processing. As an example of data processing, there is processing for image data formed by the image forming unit 210 or another device. Examples of this processing include various types of image processing, image analysis processing, and diagnostic support processing such as image evaluation based on image data.

  The data processing unit 220 includes an analysis unit 221 and a distribution information generation unit 222. The analysis unit 221 includes a specifying unit 221A, an alignment unit 221B, and a change calculation unit 221C. Distribution information generation unit 222 includes a classification unit 222A.

  The analysis unit 221 obtains a time-series change in the response of the photoreceptor to the light stimulus by analyzing the time-series image of the fundus oculi Ef of the eye E to be examined. The time-series change in the response of the photoreceptor to the light stimulus includes a time-series change in the luminance of the region corresponding to the photoreceptor. The brightness of the area is obtained in units of pixels or predetermined block areas. Further, the analysis unit 221 may obtain a time-series change in the average value of luminance in the image and the added value of luminance in the image. Photoreceptors include cones and rods.

  The specifying unit 221A specifies a plurality of photoreceptor regions corresponding to the plurality of photoreceptors by analyzing each image included in the time-series image of the fundus oculi Ef. The identifying unit 221A identifies one or more photoreceptor regions by extracting an edge region based on the luminance value of each pixel and searching for a region in which the extracted edge region has a substantially circular shape. Is possible. The specifying unit 221A may specify one or more photoreceptor regions by performing frequency analysis on each image. Further, the specifying unit 221A may specify a region having a luminance value equal to or greater than a predetermined value as a photoreceptor region based on the luminance value of each pixel.

  The alignment unit 221B aligns the plurality of photoreceptor regions specified by the specifying unit 221A between the plurality of images. The alignment unit 221B can align a plurality of photoreceptor regions between a plurality of images by a known matching method. For example, the alignment unit 221B performs alignment between the respective images included in the time-series image of the fundus oculi Ef based on the feature points. The feature points include the photoreceptor region, the blood vessel region, the optic disc, and the macula identified by the identifying unit 221A. Further, the alignment unit 221B may perform alignment between a plurality of images so as to cancel a positional shift between images estimated by the optical flow method. The alignment unit 221B may perform alignment so that the correlation between images to be aligned is high. In addition, alignment may be performed from a feature descriptor using a feature near the specified photoreceptor. The alignment unit 221B may perform alignment using a feature descriptor between images to be aligned.

  The change calculation unit 221C obtains a time-series change in the response (luminance) to the light stimulus for each photoreceptor region that has been aligned by the alignment unit 221B.

  The distribution information generation unit 222 generates photoreceptor distribution information based on the time-series change obtained by the change calculation unit 221C. The distribution information generation unit 222 can specify a photoreceptor attribute based on a time-series change in luminance based on a time-series image of the fundus oculi Ef, and can generate distribution information related to the identified photoreceptor attribute. is there. The attributes of the photoreceptor include the type of photoreceptor (L cone, M cone, S cone), whether the photoreceptor is normal or not. In addition, the distribution information generation unit 222 can specify whether or not a photoreceptor exists based on a time-series change in luminance, and can generate distribution information related to the presence of the specified photoreceptor. Distribution information includes a histogram and a map. In addition, the distribution information includes the number (the number of all photoreceptors, the number for each type of photoreceptor), the ratio of the number (cone ratio, etc.), or the determination result for the aforementioned number based on a predetermined reference value. It may be information representing (large or small).

  Distribution information generation unit 222 includes a classification unit 222A. The classification unit 222A classifies a plurality of photoreceptor regions based on the time series change in luminance for each photoreceptor region obtained by the change calculation unit 221C. The classification unit 222A classifies a plurality of photoreceptor regions by a clustering technique. Clustering methods include hierarchical clustering and non-hierarchical clustering such as k-means. In this embodiment, the classification unit 222A classifies a plurality of photoreceptor regions by the k-average method (k = 2 or more).

  In the k-average method, a cluster center position is randomly determined for each of k clusters (number of clusters) set in advance, and each data to be classified is assigned to the cluster at the nearest cluster center position. Thereafter, the center-of-gravity position is obtained as a new cluster center position for each cluster, and the process ends when the allocation to the cluster does not change or when the change amount of the cluster center position is equal to or less than a predetermined threshold.

(User interface part)
The user interface (User Interface: UI) unit 230 has a function for exchanging information between the user and the fundus analysis apparatus. The UI unit 230 includes a display device and an operation device (input device). The display device may include a display unit and may include other display devices. The operation device includes various hardware keys and / or software keys. The control unit 200 can receive an operation content for the operation device and output a control signal corresponding to the operation content to each unit. It is possible to integrally configure at least a part of the operation device and at least a part of the display device. A touch panel display is an example.

  The second irradiation system 190 is an example of an “irradiation unit” according to the embodiment. The first irradiation system 110, the light guide system 120, the first detection system 140, the second detection system 150, the third detection system, the fixation system 180, the control unit 200, and the image forming unit 210 are “time series” according to the embodiment. It is an example of a “data acquisition unit”. The time series image is an example of “time series data” according to the embodiment. The alignment unit 221B is an example of the “association unit” according to the embodiment. The UI unit 230 (display device) is an example of the “display unit” according to the embodiment.

[Operation]
An operation of the fundus analysis apparatus according to the embodiment will be described. Hereinafter, a case where the L cone and the M cone are classified by the stimulation light from the above-described bleaching light source 196 will be described.

  3 to 7 show an example of the operation of the fundus analysis apparatus according to the embodiment. FIG. 3 is a flowchart illustrating an operation example of the fundus analysis apparatus according to the embodiment. FIG. 4 is an explanatory diagram of the wavelength sensitivity of the photoreceptor. In FIG. 4, the horizontal axis represents the wavelength, and the vertical axis represents the absorption rate of the photoreceptor. FIG. 5 illustrates an operation explanatory diagram of S3 of FIG. FIG. 6 illustrates an operation explanatory diagram of S4 of FIG. FIG. 7 is an operation explanatory diagram of S7 of FIG.

(S1)
Photoreceptors have different wavelength sensitivities for each type. Specifically, as shown in FIG. 4, the wavelength sensitivities are different from each other so that the wavelength at which the light absorption rate is maximum becomes shorter in the order of L cone, M cone, rod, and S cone. When such a photoreceptor is irradiated with light of a predetermined wavelength, the reflectance of the photoreceptor changes due to bleaching reaction. Therefore, the control unit 200 controls the optical system 100 to irradiate the fundus oculi Ef of the eye E with light for light stimulation, and acquires images of the fundus oculi Ef before and after the bleaching reaction as time-series images. (S1). In S1, for example, a time-series image of the fundus oculi Ef is acquired as follows.

  First, the main control unit 201 turns off the light source 111 and the bleaching light source 196 for the first period T1 to put the eye E into a dark adaptation state.

  When the first period T1 has elapsed, the main control unit 201 turns on the light source 111 and controls the optical scanner 125 to start scanning the fundus oculi Ef of the eye E with the light from the light source 111. The image forming unit 210 forms an image of the fundus oculi Ef based on the detection result of the fundus reflected light by the light receiver 151. The main control unit 201 sequentially stores the image of the fundus oculi Ef formed by the image forming unit 210 in the storage unit 202 as a time-series image before the bleaching reaction.

  When the second period T2 has elapsed after the start of scanning of the fundus oculi Ef, the main control unit 201 turns on the bleaching light source 196 and continues scanning the fundus oculi Ef of the eye E with the light from the light source 111. As described above, light having a center wavelength of 650 nm among the light from the bleaching light source 196 is irradiated to the eye E as stimulation light. For the stimulation light, the absorption rate of the L cone is higher than that of the M cone. The image forming unit 210 continues to form an image of the fundus oculi Ef based on the detection result of the fundus reflected light by the light receiver 151. The main control unit 201 sequentially stores the image of the fundus oculi Ef formed by the image forming unit 210 in the storage unit 202 as a time series image after bleaching reaction.

  When the third period T3 elapses after the bleaching light source 196 is turned on, the main control unit 201 turns off the light source 111 and the bleaching light source 196 to stop scanning the fundus oculi Ef. As described above, in S1, a time-series image of the fundus oculi Ef in a period including a light irradiation period with a center wavelength of 650 nm (predetermined wavelength) with respect to the fundus oculi Ef of the eye E is acquired.

(S2)
The specifying unit 221A detects a cone (cone region) by analyzing time-series images of the fundus oculi Ef before and after the bleaching reaction stored in the storage unit 202. In S1, since the luminance of the L cone and the M cone mainly changes due to irradiation with light having a center wavelength of 650 nm, the specifying unit 221A detects the L cone and the M cone.

(S3)
The alignment unit 221B performs alignment of the time-series images acquired in S1. When the time-series image is composed of n (n is a positive integer of 2 or more) images, the alignment unit 221B performs alignment of the n images. Thereby, as shown in FIG. 5, alignment is performed about L cone L1-Ln and M cone M1-Mn in each image contained in a time series image.

(S4)
The change calculation unit 221 </ b> C acquires the luminances of the L cone and the M cone detected in S <b> 2 in each image subjected to the alignment in S <b> 3. Thereby, a time-series change in luminance as shown in FIG. 6 is obtained for each cone. The change calculation unit 221C may acquire the brightness of each of the L cone and the M cone detected in S2 from an image obtained by averaging two or more images subjected to the alignment in S3.

(S5)
The change calculation unit 221C performs a process of excluding the non-clustering target cones from the L cones and the M cones acquired in S4 according to a predetermined criterion. Examples of cones that are not subject to clustering include cones that are arranged at positions that overlap the blood vessel region, and cones that have a significantly large (or small) change in luminance.

(S6)
The classification unit 222A performs clustering on the cones not excluded in S5 by the k-means method, and classifies the cones into L cones and M cones. That is, the classification unit 222A distributes the cones to the L cones or the M cones by clustering the time series changes in the luminance of the cones detected from the n images.

(S7)
The distribution information generation unit 222 generates cone distribution information based on the clustering result in S6. The display control unit 201A causes the UI unit 230 to display the distribution information generated by the distribution information generation unit 222.

  For example, as shown in FIG. 7, the distribution information generation unit 222 generates a map representing the classification result by the classification unit 222A. In FIG. 7, the distribution of cones (La, Ma, Xa) detected in S2, the distribution of cones (Xa) excluded in S5, and the L cones (La) and M cones classified in S6 Each distribution of (Ma) is represented.

  In addition, the distribution information generation unit 222 can generate a histogram based on the classification result by the classification unit 222A. For example, the distribution information generation unit 222 generates a histogram for analyzing the clustering result of S6. Such a histogram includes a histogram representing the distance from each cluster center position and each cone obtained by the k-average method.

  Further, the distribution information generation unit 222 may obtain a cone ratio between the number of L cones and the number of M cones classified in S6.

  By irradiating the fundus oculi Ef with light of another central wavelength (for example, 550 nm) and repeating the same operation as described above, it is possible to further classify the L cone, the M cone, and the S cone. .

  In the above embodiment, the case where the L cone and the M cone are classified by irradiating the fundus Ef with light having a center wavelength of 650 nm has been described. The photoreceptors may be classified.

[effect]
The effect of the fundus analysis apparatus according to the embodiment will be described.

  The fundus analysis apparatus according to the embodiment includes an analysis unit (analysis unit 221) and a distribution information generation unit (distribution information generation unit 222). The analysis unit analyzes time series data (time series image) of the fundus (fundus Ef) of the eye to be examined (test eye E) to change the time series of the response of the photoreceptor (cone, cone) to the light stimulus. Ask for. The distribution information generation unit generates photoreceptor distribution information based on a time-series change.

  According to such a configuration, the photoreceptor distribution information can be generated by acquiring time-series data of the fundus of the subject's eye, so that the burden on the subject can be greatly reduced. In addition, since the distribution information of the photoreceptor is generated based on the time series change of the response of the photoreceptor to the light stimulus obtained from the time series data, the fundus can be analyzed stably. .

  In addition, the fundus analysis apparatus according to the embodiment includes an irradiation unit (second irradiation system 190) and a time series data acquisition unit (first irradiation system 110, light guide system 120, first detection system 140, second detection system 150). , A third detection system, a fixation system 180, a control unit 200, and an image forming unit 210). The irradiation unit irradiates the fundus with light having a predetermined wavelength (center wavelength is 650 nm). The time-series data acquisition unit acquires time-series data in a period including an irradiation period of light having a predetermined wavelength.

  According to such a configuration, it is possible to provide a fundus analyzer that can acquire time series data of the fundus of the subject's eye, reduce the burden on the subject, and can stably analyze the fundus. Is possible.

  In the fundus analysis apparatus according to the embodiment, the time-series data may be a time-series image of the fundus acquired in a period including an irradiation period of light with a predetermined wavelength on the fundus.

  According to such a configuration, photoreceptor distribution information can be generated based on time-series images of the fundus before and after the bleaching reaction.

  In the fundus analysis apparatus according to the embodiment, the distribution information may be information representing the distribution of the type of photoreceptor.

  According to such a configuration, it is possible to specify the distribution of photoreceptor types based on time-series data of the fundus.

  In the fundus analysis apparatus according to the embodiment, the analysis unit may include a specifying unit (specifying unit 221A), an associating unit (positioning unit 221B), and a change calculating unit (change calculating unit 221C). The specifying unit specifies a plurality of photoreceptor regions corresponding to the plurality of photoreceptors by analyzing each of the plurality of data included in the time series data. The associating unit associates the plurality of photoreceptor regions identified by the identifying unit among the plurality of data. A change calculation part calculates | requires a time-sequential change for every photoreceptor area | region matched by the matching part.

  According to such a configuration, it is possible to accurately obtain a time series change for each photoreceptor region from time series data of the fundus, and to obtain a photoreceptor distribution with high accuracy.

  In the fundus analysis apparatus according to the embodiment, the distribution information generation unit may include a classification unit (classification unit 222A). The classification unit classifies a plurality of photoreceptor regions based on the time series change for each photoreceptor region calculated by the change calculation unit.

  According to such a configuration, the photoreceptor region is classified based on the time-series change of the response of the photoreceptor to the light stimulus calculated for each photoreceptor region. And the fundus can be analyzed stably.

  In addition, the fundus analysis apparatus according to the embodiment may include a display control unit (display control unit 201A) that causes the display unit (UI unit 230) to display a map representing the classification result by the classification unit.

  According to such a configuration, it is possible to provide a fundus analyzing apparatus capable of displaying on the display means a map representing the photoreceptor classification result obtained stably while reducing the burden on the subject.

  In addition, the fundus analysis apparatus according to the embodiment may include a display control unit (display control unit 201A) that causes the display unit (UI unit 230) to display a histogram based on the classification result by the classification unit.

  According to such a configuration, it is possible to provide a fundus analyzing apparatus capable of displaying on the display means a histogram based on the photoreceptor classification result obtained stably while reducing the burden on the subject.

  In the fundus analysis device according to the embodiment, the photoreceptor may include a cone.

  According to such a configuration, it is possible to provide a fundus analysis apparatus that can reduce the burden on the subject and can stably generate the distribution information of the cones.

  Further, in the fundus analysis apparatus according to the embodiment, the time series change of the reaction may include a time series change of the luminance.

  According to such a configuration, the distribution information of the photoreceptor is generated based on the time series change of the brightness of the photoreceptor with respect to the light stimulus obtained from the time series data of the fundus of the eye to be examined. It is possible to reduce the burden on the examiner and to stably analyze the fundus.

<Modification>
The embodiment described above is merely an example for carrying out the present invention. A person who intends to implement the present invention can make arbitrary modifications, omissions, additions and the like within the scope of the present invention.

  In the above-described embodiment, the case where the configuration of the optical system 100 is the configuration illustrated in FIG. 1 has been described, but the configuration of the optical system according to the embodiment is not limited to this. For example, in the configuration illustrated in FIG. 1, the light source 111 and the bleaching light source 196 may be configured by a common light source.

  In the above-described embodiment, the case where the time-series data is a time-series image acquired by AO-SLO (Adaptive Optics-SLO) has been described, but the embodiment is not limited to this. The time series data according to the embodiment may be an image acquired by a fundus camera.

  In the above-described embodiment, the case where the fundus analysis apparatus includes the optical system 100 has been described. However, the configuration of the fundus analysis apparatus according to the embodiment is not limited to this. For example, the fundus analysis apparatus according to the embodiment may include the control unit 200, the image forming unit 210, and the data processing unit 220, and the optical system 100 may be provided outside the fundus analysis apparatus.

  In the above-described embodiment, the case of classifying the L cone and the M cone has been described, but the embodiment is not limited to this. For example, S cones and rods may be classified.

  In the above-described embodiment, the case where the classification of the photoreceptor type and the like is performed based on the time series change of the response of the photoreceptor to the light stimulus has been described. However, the fundus analysis apparatus according to the embodiment is limited to this. It is not a thing. The fundus analysis apparatus according to the embodiment may classify the type of photoreceptor based on the time-series change of the response of the photoreceptor to electrical stimulation.

100 optical system 110 first irradiation system 120 light guide system 140 first detection system 150 second detection system 160 third detection system 170 anterior ocular segment illumination system 180 fixation system 190 second irradiation system 200 control unit 201 main control unit 201A Display control unit 202 Storage unit 210 Image forming unit 220 Data processing unit 221 Analysis unit 221A Identification unit 221B Positioning unit 221C Change calculation unit 222 Distribution information generation unit 222A Classification unit 230 UI unit

Claims (9)

Analyzing the time series of the response of the photoreceptor to the light stimulus by analyzing the time series data of the fundus of the subject eye,
A distribution information generation unit that generates distribution information of the photoreceptor based on the time series change;
Including
The distribution information includes the number of all photoreceptors, the number of each photoreceptor type, the ratio of the number of the second type of the photoreceptor to the number of the first type of the photoreceptor, or a predetermined reference A fundus analysis apparatus including information indicating a determination result with respect to the number of all photoreceptors based on a value or the number of each photoreceptor type. An irradiation unit for irradiating the fundus with light of a predetermined wavelength;
A time-series data acquisition unit for acquiring the time-series data in a period including an irradiation period of light of the predetermined wavelength;
The fundus analysis apparatus according to claim 1, comprising: The fundus analysis apparatus according to claim 1, wherein the time-series data is a time-series image of the fundus acquired in a period including an irradiation period of light having a predetermined wavelength with respect to the fundus. The analysis unit
A specifying unit for specifying a plurality of photoreceptor regions corresponding to a plurality of photoreceptors by analyzing each of the plurality of data included in the time series data;
An association unit for associating the plurality of photoreceptor regions identified by the identification unit between the plurality of data;
A change calculation unit for obtaining the time-series change for each photoreceptor region associated by the association unit;
The fundus analysis apparatus according to any one of claims 1 to 3, further comprising: The distribution information generation unit includes a classification unit that classifies the plurality of photoreceptor regions based on the time-series change for each of the photoreceptor regions calculated by the change calculation unit. Item 5. A fundus analysis apparatus according to Item 4. The fundus analysis apparatus according to claim 5, further comprising a display control unit that causes a display unit to display a map representing a classification result by the classification unit. The fundus analysis apparatus according to claim 5, further comprising: a display control unit that causes a display unit to display a histogram based on a classification result by the classification unit. The fundus analyzer according to any one of claims 1 to 7, wherein the photoreceptor includes a cone. The fundus analysis apparatus according to any one of claims 1 to 8, wherein the time-series change in the reaction includes a time-series change in luminance.

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