JP2019084392A - Tear film thickness measurement apparatus and method - Google Patents

Abstract

To more accurately measure the thickness of a tear film by making variable, an incident angle of light with which the tear film is irradiated.SOLUTION: Light from a wide-band wavelength sweeping light source 31 is reflected by a galvanometer mirror 33 and a cornea is irradiated with the reflected light. By the wide-band wavelength sweeping light source 31, reflected light from the cornea is, through the galvanometer mirror 33 and a half mirror 32, detected by a detector 34 such as a photodiode, and the thickness of a tear film on the cornea is measured by a distribution information acquisition unit 44. An image collection unit 30 can obtain a distribution of reflectance for each wavelength by, for example, irradiating the identical region on the cornea with light having a plurality of wavelengths and detecting the amount of reflected light of the irradiation light, and thickness of the tear film of the irradiated region can be measured by the distribution information acquisition unit 44.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a tear film thickness measuring device and method.

For example, U.S. Pat. No. 5,075,019 "In systems and methods for performing tear film structure measurement and evaporation rate measurement, the broadband light source illuminates the tear film, and the spectrometer measures at least one point of the tear film. Measure the spectrum of each of the reflected light from “H” (see summary).
Further, Patent Document 2 describes an ophthalmologic examination apparatus for improving the reliability of type evaluation of dry eye (paragraph 0004), and Patent Document 3 describes “the accuracy and accuracy of the tear liquid examination. An ophthalmologic examination apparatus for achieving improvement (paragraph 0005) is described.

International Publication No. WO2015-132788 Japanese Patent Application No. 2016-185076 Japanese Patent Application No. 2016-185077

However, in the prior art, since the tear film is spherical, correction is performed on the premise that the shape of the cornea is spherical with a predetermined radius of curvature. However, there are individual differences in the curvature of the cornea and there is also a deviation from the spherical shape, which may cause an error in the measurement results.
In view of the above points, the present invention makes the incident angle of light irradiated to the tear film variable, and makes the measurement light incident along the normal to the measurement site based on the measurement result of the corneal shape, The purpose is to measure the thickness of the tear film layer more accurately regardless of the shape of the cornea to be examined.

According to a first solution of the invention:
Tear film thickness measuring device,
Light source,
An image acquisition unit,
A distribution information acquisition unit,
A light flux redirecting member,
A control processing unit,
Equipped with
The control processing unit controls the light flux redirecting member to cause light to be incident on the tear film in a direction normal to the surface of the subject's eye or cornea with the incident angle of the measurement light.
The image collecting unit changes the wavelength of the light source, irradiates at least the central part of the cornea of the eye to be examined, and captures the reflected image.
The distribution information acquisition unit obtains a reflectance at each wavelength of at least the central part of the cornea from the image captured by the image collection unit, obtains a spectral reflection spectrum, and analyzes the obtained spectral reflection spectrum to obtain a tear film. Determine thickness value, correlate color with layer thickness,
The distribution information acquisition unit changes the wavelength of the light source to R, G, and B, and superimposes the R, G, and B cornea images obtained by imaging a predetermined measurement range of the entire cornea or the cornea, respectively. Obtain a color image and convert the color of each region of the color image into layer thickness based on the correlation of color and layer thickness;
The distribution information acquisition unit creates and displays the layer thickness of each part in the form of a map.
There is provided a tear film thickness measuring device characterized in that

According to a second solution of the invention:
It is a tear film thickness measuring method, and
Controlling the light flux redirecting member to cause light to enter the tear film in a direction normal to the surface of the subject's eye or cornea with the incident angle of measurement light;
The wavelength of the light source is changed, and at least the central part of the cornea of the eye to be examined is irradiated, and this reflected image is imaged,
From the captured image, the reflectance at each wavelength of at least the central part of the cornea is obtained to obtain a spectral reflection spectrum, the obtained spectral reflection spectrum is analyzed to obtain a tear layer thickness value, and a correlation between color and layer thickness is obtained. Ask for
The color image is obtained by changing the wavelength of the light source to R, G, B, and superimposing the R, G, B corneal images obtained by photographing the entire cornea or a predetermined measurement range of the cornea respectively. Convert the color of each area of the color image into layer thickness, based on the correlation between
Make the layer thickness of each part map and display it,
A tear film thickness measuring method is provided.

  According to the present invention, the thickness of the tear film can be measured more accurately by individually setting the incident angle and the focus position of the light irradiated to the tear film.

Schematic which represents the structure of an ophthalmologic examination apparatus. FIG. 2 is a schematic diagram for explaining the configuration of an image acquisition unit. The flowchart showing the operation | movement of an ophthalmologic examination apparatus. FIG. 10 is a schematic view for explaining another configuration of the image acquisition unit. FIG. 10 is a schematic view for explaining still another configuration of the image acquisition unit. The flowchart showing the operation | movement for producing tear fluid thickness distribution information.

  Exemplary embodiments of the invention will be described with reference to the drawings. The contents of the documents cited in this specification and the other known techniques can be incorporated into the embodiments. (For example, refer to Patent Document 2 and Patent Document 3)

  The ophthalmologic examination apparatus (a tear film thickness measurement device) of the embodiment measures the thickness of the tear film on the cornea of the eye to be examined.

The ophthalmologic examination apparatus of this embodiment can measure the thickness of the tear film which is a thin film on a cornea by irradiating measurement light to a cornea and obtaining reflected light. The ophthalmologic examination apparatus of the present embodiment collects one or more images representing tears on the cornea by photographing the anterior segment of the eye to be examined. Furthermore, the image may be acquired by scanning in one or two dimensions. Also, time-series images may be collected.
The time-series image includes a group of images acquired at different times, and typically, a group of frames obtained by moving image shooting at a predetermined frame rate, or repeatedly photographing the anterior segment at predetermined time intervals. It may be a still image group obtained.
Hereinafter, although a time-series image is mainly described as an example, the present invention and / or the present embodiment can be applied to one or more images as described above other than the time-series image.

  The frontal image may be an image representing an interference pattern due to surface reflection and back surface reflection of a tear film (eg, oil layer).

  The ophthalmologic examination apparatus of the embodiment may have a function of capturing an eye to be examined (a function of collecting (time-series) images). In addition to or instead of this function, the ophthalmologic examination apparatus according to the embodiment has a function (function to receive (time-series) image) acquiring an image (time-series) from another device, recording medium, etc. You may be equipped.

  The function of collecting (time-series) images is realized by, for example, a known configuration for providing the function of a slit lamp microscope, a known configuration for providing the function of the OCT apparatus, etc. (image acquisition unit) .

  The configuration as a slit lamp microscope includes, for example, an illumination optical system that projects illumination light onto an eye to be examined, and an imaging optical system that detects return light of illumination light from the anterior segment with an image sensor. The illumination optical system can project slit light and includes a mechanism for changing the slit width. Furthermore, a mechanism is provided to change the relative position (the relative orientation of both optical axes) of the illumination optical system and the imaging optical system. In addition, a data processing system that processes an image obtained by the image sensor and a control system that performs various controls are provided.

  (Time-series) The function of receiving an image is, for example, from another device (image archiving system, slit lamp microscope, OCT device, etc.) via a communication line such as a local area network (LAN), the Internet, or a private line. A sequence is realized by a communication device for receiving an image, a data reader for reading data from a recording medium, and the like (image receiving unit).

  The processing functions (a calculation function, a data processing function, an image processing function, a control function, etc.) in the ophthalmologic examination apparatus according to the embodiment include, for example, hardware such as a processor and a storage device, a calculation program, an image processing program, a control program, etc. It is realized by the cooperation with software. Note that part of the hardware may be provided in an external device capable of communicating with the ophthalmologic examination apparatus. Also, at least a portion of the software may be pre-stored on the ophthalmologic examination apparatus and / or may be pre-stored on the external apparatus.

First Embodiment
<Constitution>
An exemplary embodiment of an ophthalmic examination apparatus is described. In the present embodiment, an ophthalmologic examination apparatus provided with a function (image acquisition unit) for acquiring (time-series) images will be described.

  The example of a structure of the ophthalmologic examination apparatus of this embodiment is shown in FIG. The ophthalmologic examination apparatus 1 collects a (time-series) image by repeatedly photographing the eye to be examined, analyzes each of a plurality of images included in the (time-series) image, and specifies a tear tear region.

  The ophthalmologic examination apparatus 1 can display (time-series) images and information obtained therefrom on the display device 2. As an example of information obtained from (time-series) images, there are tear film thickness distribution (thickness map) and the like. The display device 2 may be part of the ophthalmologic examination apparatus 1 or may be an external apparatus connected to the ophthalmologic examination apparatus 1.

  The ophthalmologic examination apparatus 1 includes a control unit 10, a storage unit 20, an image collection unit 30, a data processing unit 40, and an operation unit 50.

<Control unit 10>
The control unit 10 controls each unit of the ophthalmologic examination apparatus 1. The control unit 10 includes a processor. The “processor” is, for example, a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (for example, a simple programmable logic device (SPLD), a complex programmable logic device (CPLD)). Or circuit such as FPGA (Field Programmable Gate Array). The control unit 10 can realize the function according to the embodiment by, for example, reading and executing a program stored in a storage circuit or a storage device (storage unit 20, external device or the like).

  In addition, the control unit 10 may include a communication device for transmitting and receiving data via a communication line such as a LAN, the Internet, or a dedicated line.

<Display control unit 11>
The control unit 10 includes a display control unit 11. The display control unit 11 executes control for displaying information on the display device 2. The display control unit 11 can perform processing (generation, processing, combination, and the like) on information displayed on the display device 2. The processing may be performed by linking the display control unit 11 with other elements (other elements of the control unit 10, the data processing unit 40, etc.).

<Storage unit 20>
The storage unit 20 stores various information.

<Image acquisition unit 30>
The image collecting unit 30 collects one or more images representing tears on the cornea by capturing the anterior segment of the subject's eye. Furthermore, the image may be acquired by scanning in one or two dimensions. Also, time-series images may be collected. The image collection unit 30 can collect (time-series) images representing the movement of tears on the cornea by repeatedly photographing the subject's eye.

FIG. 2 is a schematic diagram for explaining the configuration of the image acquisition unit. The image collecting unit 30 includes an optical system for performing imaging, a drive system, a control system, and a processing system. For example, the image acquisition unit 30 includes a broadband wavelength swept light source 31, a half mirror 32, a galvano mirror 33, a photodiode 34, a control processing unit 35, a lens, and the like.
The broadband wavelength swept light source 31 may be, for example, a white light source including near infrared radiation combined with a spectrometer (spectrometer) such as a grating or LVF (Linear Variable Filter) to have wavelength selectivity. Examples of the white light source include a halogen lamp, a xenon lamp, and a supercontinuum light source. A light source driver (not shown) may be built in the broadband wavelength swept light source 31 or may be externally attached.
The control processing unit 35 controls the broadband wavelength swept light source 31 and the galvano mirror 33, detects a signal from the photodiode 34, and collects an image.
The image collecting unit 30 selectively emits light of a specific wavelength in the visible to near-infrared wavelength range, for example, from the broadband wavelength swept light source 31. The light from the broadband wavelength swept light source 31 is reflected by the galvano mirror 33 and is irradiated to the cornea. The reflected light from the cornea is detected by the broadband wavelength swept light source 31 through the galvano mirror 33 and the half mirror 32 by the detector 34 such as a photodiode, and the distribution information acquisition unit 44 measures the thickness of the tear film on the cornea. Ru. The image collecting unit 30 can, for example, irradiate light of a plurality of wavelengths to the same site on the cornea and detect the amount of reflected light to obtain the distribution of reflectance for each wavelength, and the distribution information acquiring unit At 44, the thickness of the tear film at the irradiation site can be measured. Further, the image collecting unit 30 scans the light flux on the cornea with the galvano mirror 33, and the distribution information acquiring unit 44 can obtain a plurality of regions on the cornea or a one-dimensional or two-dimensional tear film.

FIG. 4 is a schematic view for explaining another configuration of the image acquisition unit.
The galvano mirror 33 can scan in one or two dimensions. The galvano mirror 33 has a drive mechanism that moves back and forth with respect to the subject's eye in addition to variable direction due to rotation, thereby making the incident direction of measurement light on the subject's eye variable and causing light to enter the tear film. Can. In this case, light can be incident from the normal direction of the spherical surface of the eye or cornea.
In addition to the galvano mirror (galvano scanner) 33, an appropriate reflection direction variable member such as a reflection direction variable mirror can be used.

Furthermore, FIG. 5 is a schematic view for explaining still another configuration of the image acquisition unit. (Here, reference numeral 33 is called a scanner.)
The light from the wavelength sweeping type light source 31 passes through the lens and the half mirror 32, is reflected by the mirror, and reaches the scanner 33. The scanner 33 is capable of changing the angle of a light beam reflected by a galvano mirror or the like, and is two-dimensional by combining two scanners (mirrors) that change in the plane (y axis) and in the plane orthogonal to the plane (X axis). Enables scanning in the plane. The light reflected at an arbitrary angle by the mirror of the scanner 33 passes through the dichroic mirror and the objective lens and is irradiated to the cornea to be examined. Here, since the scanner 33 and the curvature center position of the cornea to be examined are arranged to be substantially conjugate, the light beam deflected by the scanner 33 is incident along the normal line of the cornea. A light beam incident along the normal of the cornea (perpendicular to the surface of the cornea) is reflected from the cornea (the interface of the tear fluid) and returns to the scanner 33 through the objective lens. The light beam reflected by the scanner 33 is reflected by a mirror and a half mirror, and is condensed on a stop by a lens. The luminous flux transmitted through the stop is detected by a PD (photodiode) 34. Here, the light source, the surface of the cornea, and the stop are disposed conjugately.

  The broad-band wavelength-swept light source 31 includes continuous or discrete wavelengths from at least the visible light region to the near-infrared region, and can selectively irradiate light of individual wavelengths to the eye. Alternatively, light from a white light source such as an incandescent lamp, a xenon lamp, or a super continuum light source can be used as substantially monochromatic light of individual wavelengths using a spectrometer or a color filter. The PD 34 has sufficient sensitivity at each wavelength in the measurement wavelength range (visible to near infrared), and the characteristics of sensitivity (spectral sensitivity) for each wavelength are known. The spectral sensitivity of the PD 34 may be known by calibration or the like. The cornea of the eye to be examined and the light receiving unit of the camera are optically conjugated, and an image of the cornea forms an image on the light receiving unit of the camera.

The optical system from the light source 31 to the PD 34 is housed in a housing, and the corneal apex of the eye to be examined coincides with the optical axis of the objective lens (X, Y directions) and is constant from the objective lens to the corneal apex (Z direction ) Do alignment. As a method of detecting the state of alignment, a known method is used. When the alignment state of X, Y and Z is within the allowable range, the alignment is completed, and the control processing unit 35 issues a trigger signal to start measurement (auto start). Alternatively, measurement may be triggered by pressing the measurement switch or the like by the operator (manual start).
The blink may be monitored by the camera 34, and the measurement may be started using this as a trigger.

  When the measurement is started, first, the angle of the scanner 33 is adjusted to the angle (0 °) at which the measurement light irradiates the cornea along the optical axis of the objective lens, and a specific substantially single wavelength The wavelength range is narrow) to irradiate the cornea to be examined, and the reflected light is received by the PD 34. The wavelength is swept (changed) to acquire the light quantity at each wavelength. The light reception amount of the PD 34 acquired at each wavelength is multiplied by the spectral sensitivity of the PD 34 at each wavelength to obtain a reflectance distribution for each wavelength of the cornea. By performing spectrum analysis on the obtained spectral distribution, the thickness of each of the oil / fat layer, aqueous layer and mucin layer of tears can be determined.

  The tear film thickness can be determined from the spectral distribution of the pixels corresponding to each region by changing the angle of the scanner 33 and performing the same process on the regions other than the corneal apex as well. . Since there is a correlation between the angle of the scanner 33 and the region on the cornea, the reflectance at each wavelength is recorded at each region, so combining the obtained signals produces a color image of the cornea (the cornea with a color camera It is possible to reproduce the image when observed.

When observing the time series change of the tear film continuously, the first measurement (arbitrary one measurement) is performed by the above method to obtain the thickness (absolute value) of each tear film layer, and the subsequent measurement is for the first measurement. You only need to get relative change. In this case, a change in color (interference color) at each site on the cornea relative to the first time may be observed.
Change the wavelength of the light source to three wavelengths of R (near 600 nm), G (near 500 nm), B (near 400 nm) at each angle (each part on the cornea) of scanner 33 and superimpose reflected light amount data Thus, it is possible to obtain a color image, and by acquiring and comparing the color images in time series, it is possible to know the relative temporal change of the tear film. Since the tear film thickness (absolute value) is determined in the first measurement, the tear film thickness (absolute value) at each time can be obtained by comparison with this. Although it is possible to carry out the first measurement every time, it is necessary to obtain reflectance spectral distribution for a wide wavelength range, so it takes time for one measurement. On the other hand, since only three images (RGB) can be acquired for one measurement for the second and subsequent measurements, the measurement time can be significantly shortened, and changes in tear film thickness at short time intervals can be obtained. It can be measured. Continuously acquire R image, G image, B image at equal intervals (R, G, B, R, G, B, R, B, ...) and combine the obtained image with the previous two images By obtaining a color image, it is not necessary to acquire three new images each time, and the measurement interval can be shortened.

  The thickness distribution of the tear film can be shown by measuring the thickness of the tear film at each region on the obtained cornea, creating a pseudo color thickness map in which the thickness is converted to color, and displaying it on the screen. . By arranging and displaying the thickness map at each time on the screen, changes over time can be confirmed. It is possible to present as a pseudo-moving image by switching and displaying the images for each time to the same part on the screen. A portion below the designated thickness may be emphasized and displayed, or the area of the portion may be obtained and displayed.

  With this configuration, since the SLO has almost the same configuration as that of the SLO, the multifunction peripheral with the SLO can be achieved easily by sharing most of the parts.

(Correction of corneal curvature error)
In order to efficiently acquire the corneal reflection of the incident light beam, it is desirable that the light beam be perpendicularly incident on each part of the cornea. In addition, in order to obtain high resolution tear layer thickness data, it is necessary to keep the surface of the cornea and the aperture conjugate. It is configured as an average corneal radius of curvature (e.g. r7.7 mm). However, in fact, there are individual differences in the radius of curvature of the cornea, and they are distributed in the range of about r6 mm to 9 mm, and the actual cornea has an aspheric shape in which the radius of curvature increases (loosely) from the center toward the periphery It is. Furthermore, it may be deviated from the spherical surface such as corneal astigmatism and keratoconus. When alignment is completed so that the cornea apex and the aperture stop become conjugate by the Z alignment signal with respect to the ideal r7.7 sphere, the scanner and the cornea center (r7.7 mm) are configured to be conjugate. Yes (or vice versa). However, if the radius of curvature of the cornea deviates from 7.7 mm, the relationship between the corneal apex and the corneal curvature center collapses, so either one is displaced from the expected position. Therefore, it becomes difficult to obtain an optimal result.

(Platide method)
Around the objective lens, a placido plate having a plurality of concentric light transmitting portions is disposed on a light shielding plate. The placido plate is illuminated by a light source (near infrared LED or the like) disposed on the back surface (surface opposite to the eye to be examined), and becomes a concentric light source to illuminate the cornea to be examined. The luminous flux reflected by the cornea produces a multi-ring virtual image due to the corneal curvature. The image of the virtual image is reflected by a dichroic mirror and imaged by a camera, and the distribution of the corneal shape is obtained by a known method from changes in the size and shape of each ring image. By performing correction based on the shape of the obtained cornea on tear film thickness data, it is possible to obtain a tear film thickness with high accuracy.

(OCT method)
The apparatus has an anterior segment OCT apparatus capable of acquiring an anterior segment tomographic layer (not shown). The OCT measurement light scans the anterior segment with a scanner through an objective lens. The scanning method includes radiation scan, raster scan and the like. The anterior segment cross-sectional image (including at least the corneal surface) is acquired, and the cross-sectional image is analyzed to determine the corneal shape.

  In addition, the modality for collecting (time-series) images may be arbitrary, and may include a front image acquisition unit.

  The front image collection unit is configured to acquire a front image of an anterior segment (cornea etc.), and collects (time-series) images consisting of a series of front images (front image group). The front image acquisition unit has, for example, the same configuration as that of a conventional digital slit lamp microscope.

<Data processing unit 40>
The data processing unit 40 performs various data processing. For example, the data processing unit 40 performs image processing and image analysis. The data processing unit 40 includes a distribution information acquisition unit 44.

<Distribution Information Acquisition Unit 44>
The distribution information acquisition unit 44 acquires distribution information of the thickness of the tear fluid by analyzing each of the plurality of images included in the (time-series) image.

  In the case of a fluorescent contrast image using a fluorescent dye such as fluorescein, it is possible to create distribution information by estimating the thickness of tear fluid based on the fluorescence intensity (pixel value) as in the prior art. Moreover, it is also possible to create distribution information by estimating the thickness of tear fluid based on the interference pattern by surface reflection and back surface reflection of a tear fluid layer (for example, oil layer) similarly to the past.

  The distribution information acquisition unit 44 inputs a collected image from the image collection unit 30, and acquires tear fluid thickness distribution information based on the image. When (time-series) images are obtained and segmentation is applied to each of a plurality of three-dimensional images included therein, tear fluid thickness distribution information corresponding to each three-dimensional image is acquired.

  The distribution information acquisition unit 44 obtains the thickness of the tear film at each measurement point within the scan range based on (at least one of) the identified oil reservoir area and liquid zone area. The thickness of the tear film may be, for example, any of the thickness of the oil layer region, the thickness of the liquid layer region, and the thickness of the entire tear solution. Here, the thickness of the liquid layer region may be the thickness of the liquid layer containing the mucin layer, or may be the thickness of the liquid layer not containing the mucin layer. In the latter case, the thickness of the mucin layer can also be determined.

  By such treatment, for example, the distance between the surface of the oil layer (the boundary between the oil layer and the air) and the back surface (the boundary between the oil layer and the liquid layer) or the front of the liquid layer (the boundary with the liquid layer of the oil layer) And the back surface (the boundary between the liquid layer and the cornea), the distance between the front surface of the oil layer and the back surface of the liquid layer, and the like are calculated.

  The calculation of the thickness at each measurement point is, for example, a process of counting the number of pixels corresponding to the tear film along a predetermined measurement direction, and the distance corresponding to the number of pixels and the pixel pitch obtained thereby And (distance).

  Here, the direction in which the number of pixels is counted (the above measurement direction) is arbitrary. For example, the A line direction in scanning or the normal direction at each position on the corneal surface can be applied as the measurement direction. The process of identifying the normal direction at each position of the corneal surface includes, for example, curved surface approximation of the corneal surface, identification of a tangent plane at each position, and identification of a normal to each tangent plane.

  The distribution information acquisition unit 44 can also apply processing (flating) for planarizing the specified predetermined area (for example, the corneal surface) to the three-dimensional image. Flattening facilitates calculation of the thickness. Also, by displaying a flattened image, the thickness distribution can be easily grasped.

  The distribution information acquisition unit 44 can also specify a tear destruction region based on the acquired tear thickness distribution information. The failure region is, for example, one of a region in which the oil layer is broken (a region in which the oil layer region is not detected) and a region in which the liquid layer is broken (a region in which the liquid layer region is not detected). . In the area where the entire tear fluid is destroyed, neither the oil layer nor the liquid layer is detected.

  In a typical example, the distribution information acquisition unit 44 can specify a portion where the thickness of the oil reservoir area is equal to or less than a predetermined threshold as the area where the oil reservoir is broken. In addition, the distribution information acquisition unit 44 can specify a portion where the thickness of the liquid layer area is equal to or less than the predetermined threshold as the area in which the liquid layer is broken. In addition, the distribution information acquiring unit 44 can specify a portion in which the thickness of the tear fluid region (the combined region of the oil layer region and the liquid layer region) is equal to or less than a predetermined threshold as a region where the entire tear fluid layer is destroyed.

<Operation unit 50>
The operation unit 50 is used by the user to input an instruction to the ophthalmic examination apparatus 1. The operation unit 50 may include a known operation device used for an ophthalmologic apparatus or a computer. For example, the operation unit 50 may include a mouse, a touch pad, a trackball, a keyboard, a pen tablet, an operation panel, a joystick, a button, a switch, and the like. In addition, the operation unit 50 may include a touch panel. In this case, the control unit 10 can display a GUI for operating the ophthalmologic examination apparatus 1 on the touch panel.

Front Image Acquisition Unit 60
The front image acquisition unit 60 acquires a front image of the anterior segment (cornea etc.). The process for acquiring a front image is optional. In the first example, the front image acquisition unit 60 may include a configuration for photographing the anterior segment. For example, the front image acquisition unit 60 may include an optical system of a slit lamp microscope, an optical system of a fundus camera, and the like.

  In the second example, the front image acquisition unit 60 may include a configuration for acquiring a front image of an anterior segment of the subject's eye from an external device. For example, the front image acquisition unit 60 may include a communication device for transmitting and receiving data via a communication line such as a LAN, the Internet, or a dedicated line. In this case, the front image acquisition unit 60 may acquire, for example, a patient ID, a DICOM tag, or the like as a search query for the front image of the anterior segment of the subject eye stored in the electronic medical record system or the image archiving system. it can.

  The registration between the image acquired by the image acquisition unit 30 and the front image acquired by the front image acquisition unit 60 can be performed. The registration is, for example, a process of detecting a characteristic part (corneal apex, pupil, pupil center, pupil center of gravity, iris, iris center, iris center of gravity, etc.) from both images and both images based on both feature parts. It can be done through the process of aligning.

  Similarly, registration can be performed between various maps such as the distribution map of tear film thickness, the distribution map of the fracture region, the distribution map of the evaluation result, and the front image acquired by the front image acquisition unit 60. This registration is performed, for example, using the result of the registration of the three-dimensional image on which the map is based and the front image.

<Operation>
FIG. 3 shows a flowchart showing the operation of the ophthalmologic examination apparatus.
Several examples of operations that the exemplary ophthalmic examination apparatus can perform are described. The flow of processing executed in this example is shown in FIG. It is assumed that preliminary processing such as input of patient ID and the like, alignment of the optical system with respect to the eye to be examined, focus adjustment of the optical system, optical path length adjustment, and setting of a scan range has already been performed.

(S3: Create tear film thickness distribution information)
(For details, refer to Figure 6 and its explanation.)
First, as described in the above-mentioned “(image collecting unit 30)” and the like, the image collecting unit 30 repeatedly captures the eye to be examined to collect (time-series) images representing the movement of tears on the cornea Do. Typically, at least one of fluorescence imaging and interference imaging can be performed.
Note that one or more images representing tears on the cornea are collected by imaging the anterior segment of the subject's eye. Furthermore, the image may be acquired by scanning in one or two dimensions.

  The display control unit 11 can display the collected image on the display device 2. The image to be displayed is an image obtained by applying desired rendering to a three-dimensional image, and may be, for example, a front image such as a projection image or a shadowgram, or a tomographic image such as a B-scan image. It may be a pseudo three-dimensional image such as a volume rendering image.

  When time-series images are collected, one or more three-dimensional images included in the time-series images can be rendered, and one or more rendered images obtained thereby can be displayed on the display device 2. When displaying a plurality of rendering images, it is possible to arrange them according to time series. Also, it is possible to switch and display a plurality of rendered images in chronological order.

  In addition, when a time-series image is collected, a blink image can be specified from among a series of three-dimensional images constituting the time-series image. Furthermore, the last blink image or the next image of the series of blink images can be set as the image at the start of open eye (the above-mentioned reference image).

  Subsequently, the distribution information acquisition unit 44 creates tear fluid thickness distribution information based on the acquired image.

  When a time-series image is collected, the distribution information acquisition unit 44 creates tear fluid thickness distribution information from the segmentation result for each of the plurality of images included in the time-series image. Thereby, a plurality of tear fluid thickness distribution information corresponding to a plurality of images included in the time-series image can be obtained. The plurality of tear film thickness distribution information represents temporal changes in tear film thickness distribution, that is, dynamics of tears.

(S4: Acquire the front image of the anterior segment)
Next, for example, the front image acquisition unit 60 captures the anterior eye portion, accesses the electronic medical record system or the like, or renders the image acquired in step S3, Get the front image.

  The timing for acquiring the front image may be arbitrary. For example, the front image of the anterior segment can be acquired by accessing the electronic medical record system or the like before or after step S3 or by photographing the anterior segment. Alternatively, the front image of the anterior segment can be acquired by rendering the image acquired in step S3 at an arbitrary timing after step S3.

(S5: Display a composite image of the tear film thickness distribution image and the front image)
Subsequently, the display control unit 11 (and the data processing unit 40) forms an image (tear fluid thickness distribution image) based on the tear fluid thickness distribution information created in step S3, and this tear fluid thickness distribution image and the step The front image acquired in S4 is combined and displayed on the display device 2. The tear film thickness distribution image is, for example, a pseudo color map in which the thickness value of each point represented by the tear film thickness distribution information is expressed in a pseudo color.

  In one example, the combined display of the tear fluid thickness distribution image and the front image includes image processing for combining the tear fluid thickness distribution image and the front image, and control for displaying a composite image formed thereby. In another example, the composite display includes control of overlappingly displaying the tear film thickness distribution image and the front image by using a layer display function or the like. A display image obtained by overlapping two (or more) images by display control in this way is also an example of a composite image. In the composite display, registration of the tear film thickness distribution image and the front image can be performed. This registration is performed, for example, through registration of a three-dimensional image based on the tear film thickness distribution image and a front image.

When a plurality of images or time-series images are collected, it is possible to display on the display device 2 a composite image of a tear film thickness distribution image and a front image based on one or more three-dimensional images included therein. When displaying a plurality of composite images, it is possible to arrange them according to time series. Also, it is possible to switch and display a plurality of composite images in chronological order.
(Time-series image)
In order to acquire a time-series image in FIG. 3, for example, the processes of steps S3 and S4 are repeatedly performed a predetermined number of times or time, and the acquired image (data) is stored in the storage unit 20 as a time-series image. The display control unit 11 (and the data processing unit 40) stores the time series image (data) read from the storage unit 20 as a plurality of still images or moving images on the display device 2 in step S5. Just do it.

FIG. 6 shows a flowchart representing an operation for creating tear fluid thickness distribution information. This flowchart shows an example of a detailed flowchart of step S3 of FIG.
In addition, regarding the thickness measurement of a thin film and a tear film layer, the well-known or well-known method which was described, for example in the following internet homepages or literature can be used.
Https: // www. hamamatsu. com / jp / en / technology / innovation / spectroscopic / index. html
International Publication No. 2016/147782 Fogt et al. “Interferometric measurement of tear film thickness by use of spectral oscillations”, J. Opt. Soc. Am. A / Vol. 15, No. 1 / January 1998, pp.268-275

The tear film thickness measurement according to the present embodiment will be described below.
In general, when light (white light or the like) enters the tear film, multiple reflections occur inside the layer, and the phase difference between the multiple reflected lights is determined by the wavelength of light and the optical path length. here,
Optical path length = distance along which light reciprocates in tear film layer × refractive index of tear fluid.
As described above, the color of light reflected is correlated with the thickness of the tear film (note that it is assumed that the refractive index of tears is unknown for each individual, so a predetermined value and a predetermined value should be used. Will be used). In general, the correlation between the color of light and the thickness of the tear film is a linear relationship, and the following equation may be mentioned as an example.
2nd = (m + (1/2)) λ
Here, n: refractive index, d: thickness of tear film, m: integer, λ: wavelength (corresponding to color)

However, even if the "color" is known, the "film thickness" can not be specified unless the spectral distribution is known. Therefore, if it is possible to measure both the spectral distribution and the “color” in a certain area (in this example, at least the central portion of the cornea such as the corneal apex) and obtain the “layer thickness” from the spectral distribution at this time, “ The relationship between color and layer thickness can be obtained.
In the present embodiment, the relationship between “color” and “layer thickness” is obtained by measuring the spectral distribution (spectral reflection spectrum) at least at the central part of the cornea. Then, the “layer thickness” is estimated from the “color” (obtained from the RGB color image) of the other part based on this relationship.
In addition, you may use as a reference the spectral distribution (spectral reflection spectrum) measured not only in a cornea center part but in a predetermined predetermined | prescribed position suitably.

Each step will be described below.
S101: Light source unit wavelength sweeping When measurement is started, the image acquisition unit 30 changes (sweeps) the wavelength of the light source 31 under the control of the control processing unit 35, and the specific substantially single wavelength (the wavelength range is narrow) Light is emitted to at least the central part of the cornea of the eye to be examined, and the reflected image is captured by the camera 34. The image acquisition unit 30 causes the control processing unit 35 to sweep (change) the wavelength in step S101, and outputs the image acquired at each wavelength to the distribution information acquisition unit 44, and stores the image in the storage unit 20. The acquired image also includes an image at three wavelengths of R (approximately 600 nm), G (approximately 500 nm), and B (approximately 400 nm).
S102 Acquisition of Spectral Reflection Distribution at Central Corneal Region The distribution information acquiring unit 44 obtains the reflectance at each wavelength of at least the central corneal region from the image input from the image acquisition unit 30. For example, the distribution information acquisition unit 44 obtains the reflectance distribution for each wavelength of the cornea by multiplying the luminance value of at least the pixel at the central part of the cornea of each image acquired at each wavelength by the spectral sensitivity of a known camera at each wavelength. . The distribution information acquisition unit 44 stores the acquired reflectance distribution in the storage unit 20.

S103 Layer Thickness Calculation by Spectrum Analysis The distribution information acquisition unit 44 analyzes the obtained spectral reflection spectrum to obtain a tear film thickness value. The spectral distribution from the tear film is a characteristic spectrum dependent on the film thickness, so that the film thickness can be determined by analyzing this spectrum. As an analysis method, for example, analysis by a curve fitting method (a method of obtaining a thickness at which the difference between measured values of the spectrum and the theoretical value (eg, the square of the difference, etc.) becomes minimum) or analysis by fast Fourier transform (FFT) An appropriate analysis method such as can be used.
In addition to the thickness of the entire tear film layer, the distribution information acquisition unit 44 can appropriately determine the thickness of each of the oil / fat layer of tear fluid, the aqueous layer, the mucin layer, etc. as the thickness of the entire tear film layer. .
S104 Color Image Correlation Calculation The distribution information acquiring unit 44 obtains the correlation between the color and the layer thickness from the reflection spectrum. The distribution information acquisition unit 44 stores data of correlation between color and layer thickness in the storage unit 20.
For example, “layer thickness” is determined in step S103, and “color” is already obtained in steps S101 and S102 in three wavelengths of R (near 600 nm), G (near 500 nm), and B (near 400 nm). Therefore, it can be determined by obtaining a color image by superimposing these photographed cornea images. Thereby, for example, m of the above-mentioned formula “2nd = (m + (1⁄2)) λ” can be specified, and the correlation between the color (wavelength) and the layer thickness can be obtained.

-Wide area photography of the cornea with S105 R light Next, the distribution information acquisition unit 44 performs the same processing for each pixel also with respect to the region other than the corneal apex, thereby obtaining the tear film from the spectral distribution of the pixels corresponding to each region. The thickness can be determined and the distribution of tear fluid thickness can be determined. Here, since the camera 34 is not a color camera (for example, a so-called black-and-white camera), the “color” on the cornea can not be observed directly, but the wavelength of the light source 31 is R (near 600 nm), G (near 500 nm) , B (approximately 400 nm), and by superimposing the photographed cornea images, a color image can be obtained.
First, the image collecting unit 30 sets the light source color of the light source 31 to R, and obtains an image of the entire cornea (measurement range). The image acquisition unit 30 outputs the obtained image to the distribution information acquisition unit 44 and stores the image in the storage unit 20. Do.
S106 Wide Area Wide Area Photographing with G Light Next, the image collecting unit 30 sets the light source color of the light source 31 to G and obtains an image of the entire cornea (measurement range). The image acquisition unit 30 outputs the obtained image to the distribution information acquisition unit 44 and stores the image in the storage unit 20.
S107 Wide Area Corneal Photographing with B Light Next, the image collecting unit 30 sets the light source color of the light source 31 to B and obtains an image of the entire cornea (measurement range). The image acquisition unit 30 outputs the obtained image to the distribution information acquisition unit 44 and stores the image in the storage unit 20.
S108 Color image creation by RGB image Next, the distribution information acquisition unit 44 refers to the storage unit 20 and obtains a color image (color of each area) from the R image, G image, and B image obtained by the image acquisition unit 30. And are stored in the storage unit 20. Since the distribution information acquisition unit 44 records the images at each wavelength of visible light, a color image of the cornea (when the cornea is observed with a color camera) is obtained by superimposing the images at each wavelength at a determined ratio. Image) can be reproduced.

S109 Color image layer thickness conversion The distribution information acquisition unit 44 refers to the storage unit 20 and determines the “color” of each area of the color image as “layer thickness” based on the correlation between color and layer thickness obtained in step S104. Convert (convert) to
S110 Layer Thickness Map Display The distribution information acquisition unit 44 creates the “layer thickness” of each part in the form of a map, and causes the display control unit 11 to display the “layer thickness” on the display device 22. For example, the thickness distribution of the tear film can be shown by creating a pseudo color thickness map in which the tear film thickness at each site on the cornea obtained is converted into color and displaying it on the screen. In addition, by displaying the thickness map at each time on the screen, it is possible to confirm a temporal change. In addition, it is possible to present as a pseudo-moving image by switching and displaying an image for each time to the same part on the screen. In addition, a portion below the designated thickness may be emphasized and displayed, or the area of the portion may be obtained and displayed.

  Note that the image collection unit 30 and / or the distribution information acquisition unit 44 stores the acquired, output, and / or input image, and each data such as the correlation between color and layer thickness in the storage unit 20 at an appropriate timing. And / or can be read out from the storage unit 20 and can be displayed on the display device 2 by the display control unit 11. In addition, in steps S105, S106, and S107, the acquisition order of each image of R, G, and B can be determined as appropriate.

(Time series processing)
Thereafter, when performing time-series measurement, the distribution information acquisition unit 44, the image collection unit 30, and the like loop-process step S105 and subsequent steps.
That is, when acquiring a time-sequential image, it is obtained by creating a layer thickness time-sequential map one by one by obtaining a color image by repeating step S105 or subsequent ones of FIG. However, it takes time to obtain images of three sheets (RGB) constantly and obtain a layer thickness map of one sheet, and it may be considered that the tear film changes during that time. Therefore, in the present embodiment, each image is acquired as follows. That is,
(I) A layer thickness map of the first sheet is obtained from the first R image (R1), the first G image (G1), and the first B image (B1).
(Ii) Next, for the second layer thickness map, the second R image (R2) is acquired, and the first G image (G1) and the B image (B1) already acquired are Obtained from the first R image (R2).
(Iii) Furthermore, the third layer thickness map acquires the second G image (G2), and the first B image (B1) and the second R image (R2) already acquired And G image (G2).
As described above, if only one color image is updated and a map is continuously created, the update processing becomes 1/3 compared to acquiring three color images each time. In addition, the acquisition order of each image of R, G, B can be determined suitably.

(FIG. 3, a modified example of "S4: Obtain a front image of the anterior segment")
Since the image of the anterior segment is already acquired as a color image in step S108 of FIG. 4, it is not necessary to reacquire it in step S4 of FIG. In this case, step S4 in FIG. 3 is omitted, and in the “display composite image of tear film thickness distribution image and front image” step S5 in FIG. 3, the distribution information acquisition unit 44 performs step S108 in FIG. The layer thickness map obtained in step S110 of FIG. 4 may be superimposed and displayed on the anterior segment image obtained in the above.

As described above, in the present embodiment, the thickness of the tear film is measured more accurately by turning the reflection direction variable mirror by a predetermined angle and changing the incident angle of light irradiated to the tear film. Can. Furthermore, by rotating the reflection direction variable mirror by a predetermined angle and moving it back and forth, for example, light can be incident from the normal direction of the tear film which is a spherical surface, and the thickness of the tear film can be measured more accurately. Can.
Also, in FIGS. 2 to 5 and the like of the present embodiment, an example is shown in which the reflection direction of light is made variable by the reflection direction variable member such as the Galvano mirror (or scanner) 33, but this is not limitative. Instead of the galvano mirror (or scanner) 33, a light transmission direction variable member may be used as a device configuration that transmits light. As described above, the direction of the light flux can be controlled by using an appropriate light flux direction change member such as the reflection direction variable member or the transmission direction variable member.

  The configuration described above is merely an example for suitably implementing the present invention. Therefore, any modification (omission, substitution, addition, etc.) within the scope of the present invention can be appropriately applied.

(Example of configuration)
Below, the structural example of this invention and / or this Embodiment is shown.
[Configuration Example 1]
Tear film thickness measuring device,
A light source unit, a detection unit, a control processing unit, and a light flux changing member whose traveling direction is controlled by the control processing unit, and by scanning the anterior segment of the eye to be examined, tears on the cornea An image acquisition unit for acquiring an image representing the liquid;
A distribution information acquisition unit for acquiring tear film thickness distribution information based on the image collected by the image collection unit;
A display control unit that causes a display unit to display a distribution image of the thickness of the tear fluid acquired by the distribution information acquisition unit;
Equipped with
The light source emits light of a predetermined wavelength in a visible to near-infrared wavelength range under the control of the control processing unit,
The light flux direction change member has a reflection direction determined by the control of the control reflection unit, reflects light from the light source, and irradiates the cornea.
The detection unit detects the reflected light from the cornea through the light flux direction change member,
The control processing unit obtains an image of tear fluid on the cornea from the signal detected by the detection unit, and outputs the image to the distribution information acquisition unit.
Tear film thickness measuring device.

[Configuration Example 2]
The tear film thickness measuring device described in Configuration Example 1, wherein
The light flux redirecting member is further configured to be driven to change the distance to the eye to be examined,
The tear film thickness measuring device, wherein the control processing unit adjusts an incident angle to an eye by controlling a distance and an angle to an eye to be examined.

[Configuration Example 3]
The tear film thickness measuring device described in Configuration Example 2;
The control processing unit is further characterized by controlling the light flux redirecting member to cause light to be incident on the tear film in a direction normal to the surface of the subject's eye or cornea with the incident angle of measurement light. Tear film thickness measuring device.

[Configuration Example 4]
The tear film thickness measuring device according to any one of configuration examples 1 to 3, wherein
The image collection unit emits light of a plurality of wavelengths to the same site on the cornea, and detects the amount of reflected light thereof.
The tear film thickness measuring device, wherein the distribution information acquiring unit obtains a distribution of reflectance for each wavelength, and measures a thickness of a tear film at an irradiation site.

[Configuration Example 5]
The tear film thickness measuring device according to any one of the structural examples 1 to 4, wherein
The apparatus for measuring a thickness of a tear film according to claim 1, wherein the image collecting unit scans the light flux on the cornea with the light flux redirecting member to obtain tear film thicknesses at a plurality of regions on the cornea.

[Configuration Example 6]
The tear film thickness measuring device according to any one of configuration examples 1 to 5, wherein
The image collecting unit changes the wavelength of the light source, irradiates at least the central part of the cornea of the eye to be examined, and captures the reflected image.
The distribution information acquisition unit obtains a reflectance at each wavelength of at least the central part of the cornea from the image captured by the image collection unit, obtains a spectral reflection spectrum, and analyzes the obtained spectral reflection spectrum to obtain a tear film. Determine thickness value, correlate color with layer thickness,
The distribution information acquisition unit changes the wavelength of the light source to R, G, B, and superimposes the photographed cornea images on each other to obtain a color image, and based on the correlation between color and layer thickness, each color image Convert the area color to layer thickness,
The distribution information acquisition unit creates the layer thickness of each part in the form of a map, and displays the layer thickness by the display control unit.
A tear film thickness measuring device characterized in that.

[Configuration Example 7]
The tear film thickness measuring device described in Configuration Example 6, wherein
At the first timing of the time series,
The image collection unit determines the colors of the light source to R, G, and B, respectively, captures a predetermined measurement range, and acquires an R image, a G image, and a B image.
The distribution information acquisition unit obtains a color image of the cornea at a first timing by overlapping the R image, the G image, and the B image at a predetermined ratio,
At the second timing of the time series,
The image collecting unit determines the color of the light source to any one of R, G, and B, and captures an image by capturing a predetermined measurement range.
The distribution information acquisition unit is configured to overlap the image newly photographed with any one light source color and the other two light source color images already photographed at a predetermined ratio. Get a color image of the timing cornea,
A tear film thickness measuring device characterized in that.

[Configuration Example 8]
The tear film thickness measuring device according to any one of configuration examples 1 to 7, wherein
The light source is a broadband wavelength swept light source, or a light source having wavelength selectivity, including a white light source including near-infrared radiation and a grating, LVF (Linear Variable Filter), or other spectrometer. Tear film thickness measuring device.

[Configuration Example 9]
The tear film thickness measuring device according to any one of configuration examples 1 to 8, comprising:
It further comprises a front image acquisition unit for acquiring a front image of the cornea,
The display control unit causes the display unit to display a composite image of the distribution image of the tear fluid thickness acquired by the distribution information acquisition unit and the front image acquired by the front image acquisition unit. Tear film thickness measuring device.

[Configuration Example 10]
The tear film thickness measuring device according to any one of configuration examples 1 to 9,
The tear film thickness measuring device, wherein the distribution information acquiring unit further specifies a tear damage region based on the distribution information.

[Configuration Example 11]
A tear film thickness measuring method in a tear film thickness measurement apparatus, which
The tear film thickness measuring device is
The tear solution on the cornea is scanned by scanning the anterior segment of the subject's eye, including a light source, a detection unit, a control processing unit, and a light flux direction changing member whose reflection direction is controlled by the control processing unit. An image acquisition unit for acquiring an image to be represented;
A distribution information acquisition unit for acquiring tear film thickness distribution information based on the image collected by the image collection unit;
A display control unit that causes a display unit to display a distribution image of the thickness of the tear fluid acquired by the distribution information acquisition unit;
Equipped with
The light source emits light of a predetermined wavelength in a visible to near-infrared wavelength range under the control of the control processing unit,
The light flux direction change member has a reflection direction determined by the control of the control reflection unit, reflects light from the light source, and irradiates the cornea.
The detection unit detects the reflected light from the cornea through the light flux direction change member,
The control processing unit obtains an image of tear fluid on the cornea from the signal detected by the detection unit, and outputs the image to the distribution information acquisition unit.
Tear film thickness measurement method.

Reference Signs List 1 ophthalmologic examination apparatus 2 display device 10 control unit 11 display control unit 20 storage unit 30 image collection unit 40 data processing unit 44 distribution information acquisition unit 50 operation unit

Claims (7)

Tear film thickness measuring device,
Light source,
An image acquisition unit,
A distribution information acquisition unit,
A light flux redirecting member,
A control processing unit,
Equipped with
The control processing unit controls the light flux redirecting member to cause light to be incident on the tear film in a direction normal to the surface of the subject's eye or cornea with the incident angle of the measurement light.
The image collecting unit changes the wavelength of the light source, irradiates at least the central part of the cornea of the eye to be examined, and captures the reflected image.
The distribution information acquisition unit obtains a reflectance at each wavelength of at least the central part of the cornea from the image captured by the image collection unit, obtains a spectral reflection spectrum, and analyzes the obtained spectral reflection spectrum to obtain a tear film. Determine thickness value, correlate color with layer thickness,
The distribution information acquisition unit changes the wavelength of the light source to R, G, and B, and superimposes the R, G, and B cornea images obtained by imaging a predetermined measurement range of the entire cornea or the cornea, respectively. Obtain a color image and convert the color of each region of the color image into layer thickness based on the correlation of color and layer thickness;
The distribution information acquisition unit creates and displays the layer thickness of each part in the form of a map.
A tear film thickness measuring device characterized in that.
The tear film thickness measuring device according to claim 1, wherein
At the first timing of the time series,
The image acquisition unit determines the colors of the light source to R, G, and B respectively, and images a predetermined measurement range of the whole cornea or the cornea, respectively, to obtain an R image, a G image, and a B image. Acquired,
The distribution information acquisition unit obtains a color image of the cornea at a first timing by overlapping the R image, the G image, and the B image at a predetermined ratio,
At the second timing of the time series,
The image collecting unit determines the color of the light source to any one of R, G, and B, and captures an image by capturing a predetermined measurement range.
The distribution information acquisition unit is configured to overlap the image newly photographed with any one light source color and the other two light source color images already photographed at a predetermined ratio. Get a color image of the timing cornea,
A tear film thickness measuring device characterized in that.
The tear film thickness measuring device according to claim 1 or 2, wherein
The light flux redirecting member is further configured to be driven to vary the distance to the eye to be examined.
The tear film thickness measuring device, wherein the control processing unit adjusts an incident angle to an eye by controlling a distance and an angle to an eye to be examined.
The tear film thickness measuring device according to any one of claims 1 to 3, wherein
The apparatus for measuring a thickness of a tear film according to claim 1, wherein the image collecting unit scans the light flux on the cornea with the light flux redirecting member to obtain tear film thicknesses at a plurality of regions on the cornea.
The tear film thickness measuring device according to any one of claims 1 to 4, wherein
The tear film thickness measuring device according to claim 1, wherein the light source is a light source having a wavelength selectivity, including a white light source including near-infrared radiation and a grating, an LVF (Linear Variable Filter), or another spectrometer.
The tear film thickness measuring device according to any one of claims 1 to 5, wherein
The distribution information acquiring unit further includes a liquid layer region, an oil layer region, or a portion where the thickness of a combined region of the liquid layer region and the oil layer region is a predetermined threshold or less. Alternatively, the tear film thickness measuring device is characterized in that it is specified as a rupture region of the tear fluid region.
It is a tear film thickness measuring method, and
Controlling the light flux redirecting member to cause light to enter the tear film in a direction normal to the surface of the subject's eye or cornea with the incident angle of measurement light;
The wavelength of the light source is changed, and at least the central part of the cornea of the eye to be examined is irradiated, and this reflected image is imaged,
From the captured image, the reflectance at each wavelength of at least the central part of the cornea is obtained to obtain a spectral reflection spectrum, the obtained spectral reflection spectrum is analyzed to obtain a tear layer thickness value, and a correlation between color and layer thickness is obtained. Ask for
The color image is obtained by changing the wavelength of the light source to R, G, B, and superimposing the R, G, B corneal images obtained by photographing the entire cornea or a predetermined measurement range of the cornea respectively. Convert the color of each area of the color image into layer thickness, based on the correlation between
Make the layer thickness of each part map and display it,
The tear film thickness measuring method characterized by the above.

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