WO2010134278A1

WO2010134278A1 - Anterior ocular segment observation device

Info

Publication number: WO2010134278A1
Application number: PCT/JP2010/003164
Authority: WO
Inventors: 弓掛和彦
Original assignee: 株式会社トプコン
Priority date: 2009-05-20
Filing date: 2010-05-10
Publication date: 2010-11-25
Also published as: JP5486215B2; JP2010268916A

Abstract

Disclosed is an anterior ocular segment observation device for observing the state of a corneal endothelium in detail. The anterior ocular segment observation device (100) creates a three-dimensional image of the anterior ocular segment of an eye to be examined using an OCT of full-field type. An image region identifying unit (242) analyzes the three-dimensional image and identifies the corneal endothelium region corresponding to the corneal endothelium of the anterior ocular segment. An abnormality determining unit (246) analyzes an image region including the corneal endothelium region and a region around the corneal endothelium and determines whether or not there is an abnormality of the boundary surface of the corneal endothelium, the layers within the cornea, and corneal endothelium cells as an abnormality of the corneal endothelium. A storage unit (244) stores the result of the abnormality determination therein, and the abnormality determining unit (246) compares the new result of the abnormality determination about the eye to be examined with the past result of the determination stored in the storage unit (244) and obtains temporal variation information relating to the corneal endothelium. The storage unit (244) stores disease information (245) therein in advance, and the abnormality determining unit (246) identifies the name of the disease corresponding to the result of the abnormality determination on the basis of the disease information (245).

Description

Anterior segment observation device

The present invention relates to an anterior ocular segment observation apparatus that forms an image of the anterior ocular segment of an eye to be examined using optical coherence tomography (Optical Coherence Tomography).

In recent years, optical image measurement technology that forms an image of the surface and inside of an object to be measured using light has attracted attention. Since the optical image measurement technique does not have invasiveness to the human body unlike conventional X-ray CT, it is expected to be applied particularly in the medical field. Among them, the application in the ophthalmology field has made remarkable progress along with dentistry and dermatology.

As a representative technique of optical image measurement technology, there is a technique called optical coherence tomography (optical coherence tomography method: OCT). According to this method, since an interferometer is used, measurement with high resolution and high sensitivity is possible. In addition, since weak broadband light is used as illumination light, there is also an advantage that safety to the subject is high.

As an apparatus (OCT apparatus) using OCT, for example, there is one described in Patent Document 1. The OCT apparatus generates interference light by superimposing light (signal light) passing through the cornea (signal light) and light passing through the reference object (reference light), and forms an image of the cornea based on the detection result of the interference light To do. The image obtained in this way is an image of a cross section substantially orthogonal to the traveling direction of the signal light. Such a method is called a full-field type or an en-face type.

The full field type OCT apparatus is characterized by being able to acquire high magnification and high resolution images. When this is applied to the anterior ocular segment observation, it is possible to observe, for example, the corneal microstructure (cells, etc.). The cornea has a five-layer structure including a corneal epithelium, a Bowman layer (Bowman film), a corneal stroma layer, a Desme membrane, and a corneal endothelium in order from the surface side.

As other devices capable of observing the fine structure of the cornea, a slit lamp (slit lamp microscope) and a specular microscope are known.

For example, as shown in Patent Document 2, a slit lamp is a device that acquires an image of a corneal cross section by irradiating slit light to a cornea and cutting out a part of the cornea as an optical slice. It is also used for observation of corneal endothelial cells.

The specular microscope is an apparatus derived from a slit lamp, for example, as shown in Patent Document 3, and includes an optical system for observing a specular reflection image of slit light at a higher magnification than the slit lamp, and observes the corneal endothelium. Suitable for In clinical settings, a specular microscope is used to measure the density, size, size variation, etc. of corneal endothelial cells.

Here, the cornea (particularly the corneal endothelium and the vicinity thereof) will be described. The cornea maintains transparency by adjusting the amount of water by the pumping function of corneal endothelial cells, that is, the function of discharging the water in the cornea to the anterior chamber.

However, corneal endothelial cells are not regenerated in vivo, and cells lost due to injury or the like are complemented by deformation and expansion of surrounding cells, so the number of corneal endothelial cells may gradually decrease with age. Are known. In bullous keratopathy and the like, the cell density is usually reduced to about 2500 to 3000 cells / mm ² and the pump function is weakened, resulting in corneal edema and turbidity. It is known that edema tends to occur when the cell density is less than 1000 cells / mm ^2, and turbidity easily occurs when the cell density is less than 500 cells / mm ² . The only way to deal with corneal turbidity is to deal with corneal transplantation. In addition, corneal endothelial cells are originally hexagonal, but it is known that the number of hexagonal cells decreases due to deformation and expansion accompanying cell loss.

Furthermore, it is also known that the decrease of corneal endothelial cells may be accelerated by wearing contact lenses. Thus, in corneal medical care, observation of corneal endothelial cells over time is very important.

Also, for corneal endothelium diseases, it is also important to observe the state of the sites before and after that. For example, the Descemet's membrane located in front of the corneal endothelium is linear ABZ (Antient Banded Zone) with a high electron density in the front-rear direction (depth direction) and PNBZ (homogeneous electron density) in the electron microscope findings. It is divided into “Positioner Non-Banded Zone”. The thickness of ABZ is almost constant (about 3 μm) throughout its lifetime. In addition, it is known that the thickness of the Descemet's membrane is changed by PNBZ produced by the corneal endothelium (increases to about 6 μm at the age of 60). It can be judged whether it is natural or not.

Also, on the posterior surface of the corneal endothelium, graft rejection to corneal endothelial cells and adhesion of specific deposits observed in corneal endotheliitis may be observed. As for the deposit, if the type can be specified, a non-invasive (or minimally invasive) biopsy with a light burden on the patient can be adopted. In general, identifying the cause of a disease is extremely important in treatment.

In the cornea, a collagen-like substance called PCL (Position Collagenous Layer) accumulates locally between the Descemet's membrane and corneal endothelial cells, and is observed as a hook-like projection on the posterior surface of the cornea.

JP 2009-22502 A JP 2008-259544 A Japanese Unexamined Patent Publication No. 7-79923

As mentioned above, ridges, lines, maps, etc. are known to be observed in many diseases, but with specular microscopes, a specular image of slit light is observed. Therefore, when there is a three-dimensional structural abnormality such as a Descemet's wrinkle or a droplet cornea, specularly reflected light (light reflected in a direction different from the illumination light) may not be detected. As a result, an image in which the undetected portion is blacked out (that is, there is no information) is obtained. Therefore, at present, it is only possible to observe the state of the cells depicted in the image of the detectable part and the size and distribution of the black part. The slit lamp also detects the light reflected in the direction different from the illumination light, and the same problem occurs.

In addition, specular microscopes and slit lamps are configured to detect light reflected in a different direction from the illumination light, so that the parts present at different positions in the depth direction (different depth positions) are orthogonal to the depth direction (horizontal There is also a problem that the image is observed in a direction shifted. In addition, since the amount of reflected light is proportional to the difference in refractive index between the front and back of the reflecting surface, the amount of reflected light is reduced and the image may become unclear.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an anterior ocular segment observation apparatus that enables detailed observation of the state of the anterior ocular segment, particularly the corneal endothelium and its vicinity. It is to provide.

In order to solve the above-described problem, the invention according to claim 1 divides a light beam into signal light and reference light, and the signal light passing through the anterior eye part of the eye to be examined and the reference light path are used. An optical system that generates and detects interference light by superimposing reference light, a changing unit that changes the optical path length of the reference light and / or the optical path length of the signal light, and the optical path length is changed by the changing unit And forming means for forming a three-dimensional image of the anterior segment based on the interference light detected by the optical system, and analyzing the formed three-dimensional image to form a corneal endothelium of the anterior segment. A specifying unit for specifying a corresponding corneal endothelium region; and a determination unit for analyzing the image region including the specified corneal endothelium region and its neighboring region to determine abnormality of the corneal endothelium. This is an anterior ocular segment observation device.

The invention according to claim 2 is the anterior ocular segment observation device according to claim 1, wherein the specifying unit analyzes a tomogram in a predetermined cross section of the three-dimensional image to obtain the corneal endothelium. An area is specified.

The invention according to claim 3 is the anterior ocular segment observation device according to claim 1, wherein the specifying unit is configured to input the signal light to the anterior segment based on the three-dimensional image. Including a tomographic image forming means for forming a tomographic image in a cross-section parallel to the corneal endothelium, and analyzing the pixel values of the pixels constituting the formed tomographic image to identify the corneal endothelium region.

Further, the invention according to claim 4 is the anterior ocular segment observation device according to claim 3, wherein the determination unit is configured to determine a boundary of the corneal endothelium based on a pixel value of a pixel constituting the image region. Boundary region specifying means for specifying a boundary region in the tomographic image corresponding to a plane is included, and the abnormality is determined based on the shape of the specified boundary region.

The invention according to claim 5 is the anterior ocular segment observation device according to claim 4, wherein the determination unit analyzes an arrangement of pixels constituting the boundary region and performs unevenness on the boundary surface. And an irregularity detecting means for detecting the abnormality, and determining the abnormality based on the detected irregularity.

The invention according to claim 6 is the anterior ocular segment observation device according to claim 3, wherein the determining means is configured to determine the anterior segment of the anterior segment based on the pixel values of the pixels constituting the image region. Including a layer region specifying means for specifying a layer region in the tomographic image corresponding to a predetermined layer, obtaining a thickness of the specified layer region, and determining the abnormality based on the thickness. Features.

The invention according to claim 7 is the anterior ocular segment observation device according to claim 3, wherein when it is determined that an abnormality of the corneal endothelium exists, the determination means configures the image region. An image region in the tomographic image corresponding to the PNBZ layer of the Descemet's membrane of the anterior ocular segment is determined based on the pixel value of the pixel to be obtained, the thickness of the specified image region is determined, and the determined thickness And determining whether the abnormality is congenital or acquired based on the above.

The invention according to claim 8 is the anterior ocular segment observation device according to claim 1, wherein the specifying unit is configured to input the signal light to the anterior segment based on the three-dimensional image. Including a tomographic image forming means for forming a tomographic image in a cross section orthogonal to the corneal endothelium, and analyzing the pixel values of the pixels constituting the formed tomographic image to identify the corneal endothelium region.

The invention according to claim 9 is the anterior ocular segment observation device according to claim 8, wherein the determination means configures the corneal endothelium based on a pixel value of a pixel constituting the image region. Cell region specifying means for specifying a plurality of cell regions in the corneal endothelial region corresponding to the corneal endothelial cells to be performed, and evaluation means for obtaining evaluation information on the state of the corneal endothelial cells based on the specified cell regions And determining the abnormality based on the obtained evaluation information.

The invention according to claim 10 is the anterior ocular segment observation device according to claim 9, wherein the evaluation means uses the cell density, the maximum cell area, the minimum cell area, and the average cell area as the evaluation information. And at least one of an area standard deviation, a cell area variation coefficient, a hexagonal cell region appearance rate, and a cell area histogram.

The invention according to claim 11 is the anterior ocular segment observation device according to claim 1, wherein the determination means includes storage means for storing a determination result of the abnormality of the corneal endothelium, and the eye to be examined A new abnormality determination result is compared with the stored past determination result, and aging information of the corneal endothelium is obtained based on the comparison result.

The invention according to claim 12 is the anterior ocular segment observation device according to claim 1, wherein the determination means includes storage means for previously storing disease information that associates a disease name with an abnormality of the corneal endothelium. A disease name corresponding to the determination result of the abnormality of the corneal endothelium is specified based on the disease information.

The invention according to claim 13 divides a light beam into signal light and reference light, and superimposes the signal light passing through the anterior eye portion of the eye to be examined and the reference light passing through the reference light path. An optical system that generates and detects interference light, a changing unit that changes an optical path length of the reference light and / or an optical path length of the signal light, and a detection that is performed by the optical system while changing the optical path length by the changing unit. Forming means for forming a three-dimensional image of the anterior segment based on the interference light, and analyzing a tomographic image at each of a plurality of cross sections of the formed three-dimensional image, so that the cornea of the anterior segment Identifying means for identifying a corneal endothelium region corresponding to the endothelium, and determining an abnormality of the corneal endothelium by analyzing the image region including the identified corneal endothelium region and its neighboring region for each of the plurality of tomographic images Determination means and the plurality Display means for displaying a tomographic image is determined as the abnormal among the tomographic image, an eye observation apparatus before, characterized in that it comprises a.

The anterior ocular segment observation apparatus according to the present invention performs measurement while changing the optical path length of reference light or signal light to form a three-dimensional image of the anterior ocular segment, and uses full-field type OCT. is there. Furthermore, the anterior ocular segment observation device according to the present invention analyzes the formed three-dimensional image to identify the corneal endothelium region, and analyzes the image region including the corneal endothelium region and its neighboring region to analyze abnormalities of the corneal endothelium. Determine.

According to the present invention, since full-field type OCT is used, there is no problem with specular reflection light such as a specular microscope, and therefore there is no inconvenience that a part of an image is blacked out. In addition, according to the present invention, unlike the specular microscope, etc., it is configured to detect reflected light that travels in the direction opposite to the illumination light irradiation direction, so that parts existing at different depth positions are observed to be shifted in the horizontal direction. There is no inconvenience. Further, according to the present invention, the abnormality of the corneal endothelium is determined by analyzing the image area including the corneal endothelium region corresponding to the corneal endothelium of the anterior eye portion and the vicinity thereof, so that the abnormality of the corneal endothelium is determined. Can be automatically determined, and the accuracy and efficiency of observation of the anterior segment can be improved. Therefore, according to the present invention, it is possible to observe in detail the state of the anterior segment of the eye to be examined, particularly the state of the corneal endothelium and its vicinity.

In addition, the anterior ocular segment observation apparatus according to the present invention identifies a corneal endothelium region by analyzing tomographic images at each of a plurality of cross sections of a three-dimensional image of the anterior ocular segment formed using full-field type OCT. Then, for each tomographic image, an image region including the corneal endothelium region and its neighboring region is analyzed to determine abnormality of the corneal endothelium, and a tomographic image determined to be abnormal among a plurality of tomographic images is displayed. It is configured.

According to the present invention, there is no inconvenience that a part of an image is blackened out due to a problem with specular reflection light, and there is no inconvenience that parts existing at different depth positions are observed while being shifted in the horizontal direction. Furthermore, since the corneal endothelium is determined to be abnormal for a plurality of tomographic images, and the tomographic image determined to be abnormal is displayed, the examiner mainly observes the site determined to be abnormal. Thus, it is possible to improve the accuracy and efficiency of anterior segment observation. Therefore, according to the present invention, it is possible to observe in detail the state of the anterior segment of the eye to be examined, particularly the state of the corneal endothelium and its vicinity.

It is the schematic showing an example of the whole structure of embodiment of the anterior ocular segment observation apparatus concerning this invention. It is a schematic block diagram showing an example of the structure of the control system of embodiment of the anterior ocular segment observation apparatus concerning this invention. It is a schematic block diagram showing an example of the structure of the control system of embodiment of the anterior ocular segment observation apparatus concerning this invention. It is the schematic showing an example of a structure of the control system of embodiment of the anterior ocular segment observation apparatus concerning this invention. It is the schematic for demonstrating embodiment of the anterior ocular segment observation apparatus concerning this invention.

An example of an embodiment of the anterior ocular segment observation device according to the present invention will be described. This anterior ocular segment observation apparatus is used for observing the anterior ocular segment of a subject's eye with cell-level resolution. In particular, this anterior ocular segment observation apparatus is used for observing the corneal endothelium and the vicinity thereof (Desme's membrane, anterior chamber, etc.). As this vicinity, a range necessary for treating the corneal endothelium can be appropriately set.

The anterior segment represents the region from the cornea to the front of the lens. However, the anterior ocular segment observation apparatus can also acquire an image of a site (rear eye segment) behind the front surface of the crystalline lens by moving the reference mirror as described later.

[Constitution]
An example of the configuration of the anterior segment observation apparatus according to this embodiment is shown in FIG. The anterior ocular segment observation apparatus 100 is a full-field type OCT apparatus similar to the apparatus described in Patent Document 1.

A full-field type OCT apparatus irradiates a cornea with signal light having a predetermined beam diameter, and detects interference light obtained by causing the signal light passing through the cornea and reference light to interfere with each other with a two-dimensional photosensor array. Thus, a device for acquiring a two-dimensional image of the cornea region corresponding to the beam diameter of the signal light.

Full-field OCT devices are compared with anterior segment observation devices (slit lamps, specular microscopes, etc.) other than OCT devices, and other types of OCT devices (time domain type, Fourier domain type, swept source type, etc.). High resolution.

The eye E is arranged in a state suitable for measurement. For example, when the eye E is a living eye, jelly, liquid, or the like for reducing the change in the refractive index at the boundary can be applied to the eye E. Moreover, you may make it measure by mounting | wearing the living eye with the attachment which has the same effect | action. On the other hand, when the eye E is an isolated eye, the eye E can be placed in a liquid immersion state in order to reduce the change in the refractive index at the boundary.

The anterior ocular segment observation apparatus 100 includes a light source unit 1. The light source unit 1 outputs a non-polarized broadband light M. Although not shown, the light source unit 1 includes a halogen lamp, an optical fiber bundle that guides light output from the halogen lamp, and a Kohler illumination optical system for uniformly illuminating the irradiation field of the output light. And so on. The non-polarized broadband light M output from the light source unit 1 has a predetermined beam diameter.

The light source is not limited to the halogen lamp, and may be any light source that outputs non-polarized broadband light. For example, an arbitrary thermal light source (a light source based on black body radiation) such as a xenon lamp can be applied. The light source may be a laser light source that outputs broadband light with random polarization. Here, non-polarized light means a polarization state including linearly polarized light, circularly polarized light, and elliptically polarized light. Random polarization means a polarization state having two linearly polarized light components orthogonal to each other and the power of each linearly polarized light component changes randomly in time (see, for example, JP-A-7-92656). Hereinafter, only the case of non-polarized light will be described in detail, but in the case of random polarized light, the same effect can be obtained with the same configuration.

Now, the broadband light M output from the light source unit 1 includes light of various bands. The filter 2 is a filter that transmits only a predetermined band of the non-polarized broadband light M. The band to be transmitted is determined by the resolution, measurement depth, and the like, and is set to a band having a center wavelength of about 760 nm and a wavelength width of about 100 nm, for example. In this case, an image with a resolution of about 2 μm can be acquired in each of the depth direction of the eye E (z direction shown in FIG. 1) and the direction orthogonal to the depth direction (horizontal direction). The light transmitted through the filter 2 is also referred to as broadband light M. In this specification, the −z direction may be referred to as a forward direction, and the + z direction may be referred to as a backward direction.

The non-polarized broadband light M transmitted through the filter 2 is divided into two by a beam splitter 3 such as a half mirror. That is, the reflected light from the beam splitter 3 forms the signal light S, and the light transmitted through the beam splitter 3 forms the reference light R.

The signal light S is focused on the eye E by the objective lens 11 while maintaining the non-polarized state. The signal light S is applied to the cornea Ec with a predetermined beam diameter. At this time, the incident direction of the signal light LS with respect to the eye E is the + z direction (depth direction). The signal light LS irradiated to the eye E is reflected and scattered on the surface and inside of the eye E. This reflected light or scattered light returns to the beam splitter 3 via the objective lens 11.

On the other hand, the non-polarized reference light R generated by the beam splitter 3 passes through the wave plate (λ / 4 plate) 4 and the polarizing plate 5 and is reflected by the reflection mirror 6. Further, the reference light R passes through the glass plate 7 and is focused on the reflecting surface of the reference mirror 9 by the objective lens 8. The reference light R reflected by the reference mirror 9 returns to the beam splitter 3 via the same optical path in the reverse direction.

At this time, the reference light R, which was initially unpolarized, is converted into circularly polarized light by passing through the wave plate 4 and the polarizing plate 5 twice. The glass plate 7 is a dispersion correction optical element that minimizes the influence of dispersion that occurs in the optical path of the signal light S and the optical path of the reference light R (both arms of the interferometer).

The reference mirror 9 is movable by the reference mirror moving mechanism 10 in the traveling direction of the reference light R, that is, in the direction orthogonal to the reflecting surface of the reference mirror 9 (in the direction of a double-sided arrow in FIG. 1). The reference mirror moving mechanism 10 includes drive means such as a piezo element and a pulse motor.

The optical path length of the reference light R (reference optical path length) is changed by moving the reference mirror 9 in this way. The reference optical path length is a reciprocal distance between the beam splitter 3 and the reference mirror 9. By changing the reference optical path length, images at various depth positions of the cornea Ec can be selectively acquired. That is, the interference light L includes the shape information of the site at the depth position of the cornea Ec where the optical path length of the signal light S (signal optical path length) is equal to the reference optical path length, and the interference light L is detected and detected at the depth position. An image is formed. The reference mirror moving mechanism 10 is an example of the “changing unit” in the present invention.

In this embodiment, the reference optical path length is changed. However, the signal optical path length may be changed. In that case, a mechanism capable of changing the distance between the apparatus optical system and the eye E is provided. Examples of this mechanism include a stage that moves the apparatus optical system in the z direction and a stage that moves the eye E in the z direction. It is also possible to apply a configuration in which both the reference optical path length and the signal optical path length can be changed.

The signal light S that has passed through the eye E and the reference light R that has passed through the reference mirror 9 are superimposed by the beam splitter 3 to generate interference light L. The interference light L includes an S-polarized component and a P-polarized component. The interferometer including the light source unit 1, the beam splitter 3, the objective lens 8, the reference mirror 9, the objective lens 11 and the like, and the

CCDs

16 and 17 constitute an example of the “optical system” of the present invention.

The interference light L generated by the beam splitter 3 passes through the aperture stop 12 and becomes focused light by the imaging lens (group) 13. The S-polarized component L1 of the interference light L that has become focused light is reflected by the polarization beam splitter 14 and detected by a CCD (image sensor) 16. On the other hand, the P-polarized light component L2 of the interference light L passes through the polarization beam splitter 14, is reflected by the reflection mirror 15, and is detected by the CCD (image sensor) 17.

Each

CCD

16, 17 has a two-dimensional light receiving surface. The S-polarized component L1 and the P-polarized component L2 are applied to the light receiving surfaces of the

CCDs

16 and 17 with a predetermined beam diameter, respectively.

The CCD 16 that has detected the S-polarized component L1 sends a detection signal to the computer 20. Similarly, the CCD 17 that has detected the P-polarized component L <b> 2 sends a detection signal to the computer 20.

Since the reference light R that is the source of the interference light L is circularly polarized and the signal light S is non-polarized, the S-polarized component L1 and the P-polarized component L2 have a phase difference of 90 degrees (π / 2). ing. Therefore, a detection signal _{C A} output from the CCD 16, the detection signal _{C B} outputted from the CCD17 has a phase difference of 90 degrees can be expressed by the following equation.

Here, (x, y) represents coordinates in an arbitrary two-dimensional coordinate system set in the horizontal direction. I _s (x, y) represents the intensity of the signal light S, and I _r (x, y) represents the intensity of the reference light R. Δφ (x, y) represents the initial phase difference. Each detection signal C _A , C _B includes a background light component (non-interference component, DC component) I _s (x, y) + I _r (x, y). Furthermore, the detection signal C _A comprises an interfering component (AC component) consisting of cos component, the detection signal C _B includes the interference component (AC component) consisting sin component.

As can be seen from the equations (1) and (2), each of the detection signals C _A and C _B has only the space (the x direction and the y direction orthogonal to the z direction) as variables, and the time is a variable. Not including as. That is, the interference signal according to the present embodiment includes only a spatial change.

[Control system configuration]
The configuration of the control system of the anterior segment observation apparatus 100 will be described. 2A and 2B show an example of the configuration of the control system of the anterior segment observation apparatus 100. FIG.

The computer 20 includes a control unit 21, a display unit 22, an operation unit 23, and a signal processing unit 24.

(Control part)
The control unit 21 controls each unit of the anterior segment observation apparatus 100. For example, the control unit 21 performs control of turning on / off the light source unit 1, controlling the reference mirror moving mechanism 10, controlling the exposure time of the

CCDs

16 and 17, and controlling display processing by the display unit 22.

The control unit 21 includes a microprocessor such as a CPU and a storage device such as a RAM, a ROM, and a hard disk drive. A computer program (not shown) for device control is stored in advance in the ROM and hard disk drive. The above control by the control unit 21 is executed by the microprocessor operating according to this computer program.

Further, the control unit 21 may include a communication device for performing data communication with an external device. Communication devices include LAN cards and modems. Thereby, the control part 21 can acquire various information from an external database, or can register information in a database. In addition, information can be acquired from an ophthalmic apparatus such as an examination apparatus, or information can be transmitted to the ophthalmic apparatus.

(Display section)
The display unit 22 is controlled by the control unit 21 to display various information. The display unit 22 includes an arbitrary display device such as an LCD or a CRT display.

(Operation section)
The operation unit 23 is used by an operator to operate the anterior ocular segment observation apparatus 100 and input various kinds of information. The operation unit 23 includes an arbitrary operation device and an input device such as a mouse, a keyboard, a joystick, a trackball, and a dedicated control panel.

(Signal processing part)
The signal processing unit 24 executes various signal processing and image processing. The signal processing unit 24 includes a microprocessor such as a CPU, a RAM, a ROM, a hard disk drive, and the like. A computer program for causing the microprocessor to execute various processes described later is stored in advance in the ROM and the hard disk drive. The signal processing unit 24 includes an image forming unit 241, an image region specifying unit 242, a storage unit 244, and an abnormality determination unit 246.

(Image forming part)
The image forming unit 241 forms horizontal images at various depth positions of the anterior segment of the eye E based on the detection signals C _A and C _B output from the

CCDs

16 and 17. Furthermore, the image forming unit 241 forms a three-dimensional image of the anterior segment based on these horizontal images. The image forming unit 241 is an example of the “forming unit” in the present invention.

Here, a specific example of processing for forming an anterior eye image will be described. When the operator performs a predetermined measurement start operation using the operation unit 23, the control unit 21 turns on the light source unit 1. In this operation example, the light source unit 1 is turned on and the continuous light of the broadband light M is output.

Next, the control unit 21 controls the reference mirror moving mechanism 10 to set the optical path length of the reference light R to the first optical path length. The control unit 21 controls the exposure time of the

CCDs

16 and 17. The CCDs 16 and 17 output interference light detection signals C _A and C _B , respectively.

Subsequently, the control unit 21 controls the reference mirror moving mechanism 10 to switch the optical path length of the reference light R to the second optical path length. The control unit 21 controls the exposure times of the

CCDs

16 and 17 to output new detection signals C _A ′ and C _B ′.

Here, the first optical path length and the second optical path length are such that the detection signal C _A and the detection signal C _A ′ have a phase difference of 180 degrees (π), and the detection signal C _B and the detection signal C _B. Is set in advance so as to be a distance interval having a phase difference of 180 degrees (π). Since the detection signals C _A and C _B have a phase difference of 90 degrees, the four detection signals C _A , C _B , C _A ′, and C _B ′ for each phase difference of 90 degrees are obtained by the pair of measurements described above. Will be obtained.

The image forming unit 241 adds the detection signals C _A and C _A ′ (phase difference 180 degrees) and divides the sum by 2 to obtain the background light component I _s (x, y) + I _r (x, y ) Is calculated. This calculation process may be performed using the detection signals C _B and C _B ′ (phase difference 180 degrees).

Further, the image forming unit 241 obtains an interference component (cos component, sin component) by dividing the background light component I _s (x, y) + I _r (x, y) from the detection signals C _A and C _B. Then, the image forming unit 241 forms an image in a cross section in the xy direction (horizontal direction) by calculating the square sum of the interference components of the detection signals C _A and C _B. This process may be performed using the detection signals C _A ′ and C _B ′ (phase difference 180 degrees).

The control unit 21 sequentially performs the above-described pair of measurements while sequentially changing the optical path length of the reference light R, thereby sequentially obtaining xy cross-sectional images (horizontal tomographic images) at various depth positions of the anterior segment. Form. In this embodiment, in particular, horizontal tomographic images of the Descemet's membrane and corneal endothelium are acquired.

In this process, the control unit 21 controls the

CCDs

16 and 17 to output detection signals at a predetermined frame rate and at the same timing, and also refers to the frame rate and the exposure timing of each

CCD

16 and 17. The change timing of the optical path length of the light R is synchronized.

At this time, it is desirable to set the exposure time of each

CCD

16, 17 to be shorter than the frame interval (the reciprocal of the frame rate). For example, the frame rate of the

CCDs

16 and 17 is set to 30 f / s, and the exposure time is set to about 30 to 50 μs.

Further, by using the broadband light M having a center wavelength of about 760 nm and a wavelength width of about 100 nm, an image with a resolution of about several μm can be acquired. For example, assuming that the wavelength of the broadband light M is Gaussian and the refractive index of the eye E is n = 1.33, the theoretical value of resolution is about 1.8 μm.

The horizontal tomographic image of the anterior segment acquired in this way is stored in the storage unit 244, for example. Further, the control unit 21 causes the display unit 22 to display a horizontal tomographic image in response to an operation using the operation unit 23, for example.

When a plurality of horizontal tomographic images having different depth positions are obtained, the image forming unit 241 performs a known complement process for complementing pixels between adjacent horizontal tomographic images, thereby performing a three-dimensional image (such as volume data). Called). Volume data is image data defined by voxels that are three-dimensional pixels. This three-dimensional image is acquired for a region in the cornea including the corneal endothelium and the vicinity thereof (Desme's membrane, anterior chamber, etc.).

Also, the image forming unit 241 selects voxels located in the cross section along the depth direction from the volume data, and forms a tomographic image (vertical tomographic image) along the depth direction based on these voxels.

Also, instead of volume data, it is also possible to form a three-dimensional image (called stack data or the like) obtained by arranging a plurality of horizontal tomographic images in one three-dimensional coordinate system. A vertical tomographic image can be formed based on the stack data.

Note that the cross-sectional position in the depth direction in the three-dimensional image can be automatically designated, or the cross-sectional position can be designated manually by the operator. As an example of the former case, the cross-sectional positions can be set at predetermined intervals. It is also possible to automatically set a cross-sectional position designated in the past. Further, a predetermined cross-sectional position (for example, a cross-section passing through the corneal apex) may be automatically set. On the other hand, as an example of the latter case, for example, a pseudo three-dimensional image obtained by rendering volume data is displayed on the display unit 22, and the cross-sectional position is displayed on the pseudo three-dimensional image using the operation unit 23. Can be configured to set.

It should be noted that instead of forming a vertical tomographic image having a cross section orthogonal to the horizontal tomographic image that is formed first, it is also possible to form a tomographic image that intersects the horizontal tomographic image at an arbitrary angle. For example, it is possible to form a tomographic image along the radial direction of the cornea Ec. It is also possible to form a horizontal tomographic image at a depth position between adjacent horizontal tomographic images formed first based on the complemented voxels in the volume data.

That is, when a cross-sectional position is specified for a three-dimensional image such as volume data or stack data, a pixel (voxel, pixel) on the two-dimensional cross section is selected, and the selected pixel is moved along the two-dimensional cross section. A tomographic image is formed by arranging. By such processing, a tomographic image corresponding to an arbitrary cross section of the anterior segment can be formed. Note that the processing for forming a tomographic image from the three-dimensional image as described above is executed by the tomographic image forming unit 243 of the image region specifying unit 242.

(Image area identification part)
The image region specifying unit 242 analyzes the three-dimensional image formed by the image forming unit 241 and specifies a corneal endothelium region corresponding to the corneal endothelium of the anterior eye portion of the eye E to be examined. The specified corneal endothelium region only needs to include at least a part of the corneal endothelium of the anterior segment. Note that an image region (near region) corresponding to the Descemet's membrane or the anterior chamber is located near the corneal endothelium region in the three-dimensional image.

The image area specifying unit 242 may specify, for example, an image area (including a corneal endothelium area and a neighboring area) set in advance according to a site where the abnormality determination process is performed. As a specific example, when a part of the anterior segment that is the target of the abnormality determination process is specified in advance (automatic or manual), the image region specifying unit 242 specifies an image region in a range corresponding to the specified portion. The image area specifying unit 242 is an example of the “specifying unit” of the present invention.

The image area specifying unit 242 can also specify a target image area by analyzing the 3D image (volume data or stack data) itself, or a tomographic image (vertical tomographic image or horizontal tomographic image) based on the 3D image. The target image area can also be specified by analyzing. It is also possible to specify a target image region by analyzing a horizontal tomographic image that is the basis of a three-dimensional image.

Note that, when a three-dimensional image region is specified by analyzing a three-dimensional image, a target image region can be obtained by designating a cross section of the three-dimensional image region. In addition to a vertical tomographic image and a horizontal tomographic image, a tomographic image in a cross section in an arbitrary direction can be analyzed to specify a target image region.

Hereinafter, a specific example of the processing of the image area specifying unit 242 will be described. As described above, the target image region includes a corneal endothelium region corresponding to the corneal endothelium. Therefore, it is necessary to specify the corneal endothelium region in the analysis target image.

As an example of this process, there is a method of specifying a corneal endothelium region based on a positional relationship with a characteristic part of the anterior segment. Examples of the characteristic portion include the corneal surface, the corneal back surface, the front lens surface, and the iris. When applying this processing example, information that records the standard positional relationship (distance, direction) between the feature region and the corneal endothelium is stored in the storage unit 244 in advance, and the feature region in the image is specified. Then, it is possible to specify the corneal endothelium region in the image based on this characteristic part, the above information, and the measurement magnification (depending on the refractive power of the lens such as the objective lens).

It is also possible to grasp the fine structure of cells and the like by analyzing the pixels constituting the image to be analyzed, and specify the corneal endothelium region based on this fine structure.

An example of this processing will be described. By the way, the corneal endothelial cell is a monolayer cell located in the deepest part of the cornea. Corneal endothelial cells are uniformly arranged in a paving stone shape. The shape of corneal endothelial cells is generally a 5-7 heptagon, and most are hexagons. Corneal endothelial cells usually have a diameter of about 20 μm and an area of about 300 to 350 μm ² .

The image area specifying unit 242 first extracts an image area (cell area) of a cell depicted in the tomographic image based on the pixel values of the pixels constituting the tomographic image (horizontal tomographic image). In general, in an image acquired by applying full-field type OCT, a cell boundary region has high luminance, and a cell internal region has low luminance. This is due to the fact that the scattering at the cell boundary region is larger than the scattering at the inner region. The image region specifying unit 242 performs threshold processing based on such characteristics to specify an image region corresponding to a cell boundary region, and thereby extracts a cell region.

Note that the process of extracting a cell region is not limited to the above example, and any known technique for extracting a predetermined image region in an image can be applied. For example, binarization processing or filter processing can be used.

The pixel value is a luminance value in the case of a monochrome image and an RGB value in the case of a color image. An image acquired by the OCT apparatus is generally a monochrome image. A pseudo color image may be formed based on the distribution of luminance values.

Subsequently, the image region specifying unit 242 analyzes the cell region extracted by the above processing, and generates cell information indicating the form (size or shape) of the cell region. The cell size is calculated with reference to the measurement magnification of the image. The measurement magnification is set at the time of image acquisition. If the magnification is known, a scale of distance (unit distance) and a pixel interval in the image can be acquired. The diameter and circumference of the cell region can be easily calculated based on the unit distance and the pixel interval. In addition, for example, the area of the cell region is obtained by counting the number of pixels included in the unit area to obtain the unit area pixel number, and counting the number of pixels in the cell region. It can be calculated by dividing. It is also possible to obtain the area by performing a normal integration operation.

Further, the shape of the cell region can be specified based on the arrangement of pixels constituting the image region corresponding to the boundary region of the cell specified in the above processing. In addition, the shape of a cell (such as a cross-sectional shape in the horizontal direction) can be obtained based on this wire model by creating a wire model by thinning an image region corresponding to a cell boundary region, for example. Note that such a wire model generally includes a boundary region of a plurality of cells. The boundary area of a single cell can be specified by searching a loop-shaped image area that does not include a part of the wire model inside.

Further, the shape can be determined by, for example, calculating a differential coefficient at each position on the loop-shaped image region, or using a pattern matching process or the like.

When determining whether or not the cell depicted in the horizontal tomographic image is a corneal endothelial cell, for example, it is determined whether or not the shape of each specified cell region is a substantially hexagonal shape (for example, with a template image having a hexagonal shape). When the substantially hexagonal cell region is present in a predetermined ratio or more, it is determined that the tomographic image is an image of the corneal endothelium. By such processing, it is possible to specify an image region including a corneal endothelium region.

Further, a statistical value (average value or the like) of the size of the specified cell region is obtained, and it may be determined whether the average value is within a predetermined range (preset based on the size). It is possible to specify an image area. In addition, even if it is determined by pattern matching or the like whether the plurality of specified cell regions have a characteristic arrangement of corneal endothelium (a cobblestone-like substantially uniform arrangement), the target image area can be specified. Is possible.

The image region specifying unit 242 performs the above-described processing on each of a plurality of horizontal tomographic images having different depth positions, and determines whether each horizontal tomographic image is a corneal endothelium image. A group of horizontal tomographic images determined as images of the corneal endothelium corresponds to the corneal endothelium region. Further, the horizontal tomographic image existing in front (−z direction) of the corneal endothelium region is a neighborhood region corresponding to the front side vicinity (Desme membrane etc.) of the corneal endothelium. Further, the horizontal tomographic image existing behind the corneal endothelium region is a neighborhood region corresponding to the posterior vicinity of the corneal endothelium (such as the anterior chamber).

Thus, when the corneal endothelium region and the vicinity region are specified based on the horizontal tomographic image, the depth range (z coordinate value) of the corneal endothelium region is obtained. Based on this z coordinate value, it is possible to specify a corneal endothelium region in a vertical tomographic image or a three-dimensional image.

In the above example, the case of a horizontal tomographic image has been described in detail. However, a corneal endothelium region or the like can be specified by analyzing a vertical tomographic image or a three-dimensional image. For example, it is possible to specify a corneal endothelium region by analyzing a three-dimensional aspect (volume, shape, arrangement, etc.) of a cell region in a three-dimensional image based on pixel values.

As for the vertical tomographic image, it is possible to specify the corneal endothelium region by analyzing the two-dimensional aspect (cross-sectional area, shape, arrangement, etc.) of the cell region based on the pixel value. Further, the pixel values of the pixels constituting the vertical tomographic image are analyzed, and the boundary region between the layers is specified by obtaining adjacent pixels whose pixel values change rapidly. Thereby, a boundary region between the corneal endothelium region and the image region corresponding to the Descemet's membrane, a boundary region between the corneal endothelium region and the image region corresponding to the anterior chamber, and the like are specified. Note that which layer is the corneal endothelium region can be determined based on the aforementioned cell information. It is also possible to specify a corneal endothelium region by storing a range of pixel values peculiar to the corneal endothelium region in advance and specifying a pixel group having a pixel value included in this range.

(Memory part)
The storage unit 244 stores various types of information. The storage unit 244 is an example of the “storage unit” in the present invention. The information stored in the storage unit 244 includes the image formed by the image forming unit 241, the image region specified by the image region specifying unit 242 (its coordinate values and the image itself), and the tomographic image forming unit 243. There are tomographic images, subject information (medical chart information, etc.).

In addition, the disease information 245 is stored in the storage unit 244 in advance. The disease information 245 is information that associates a disease name with an abnormality of the corneal endothelium. An example of the disease information 245 is shown in FIG. The disease information 245 associates findings (abnormalities in morphology) of various parts of the anterior segment with disease names.

In the disease information 245 of FIG. 3, there are columns indicating the tendency of findings (for example, “light”, “irregular”, etc.), but in actual disease information, these columns include partial thresholds and allowable values. Numerical information such as range is recorded. Such numerical information is preset based on, for example, statistical values (average value, standard deviation, etc.) of many findings acquired clinically.

In addition, regarding the findings regarding the presence of a specific substance such as a cellular degeneration or a collagen-like substance, the description of the lesion or the specific substance in the image (pixel value, size, number, density, etc.) is recorded.

As findings recorded in the disease information 245, for example, it is possible to refer to various documents in addition to “Corner Clinic 2nd Edition” (Medical Shoin, 2003) supervised by Shinzo Manabe et al. In addition, it is possible to update the disease information 245 appropriately with reference to new research results and papers.

In the disease information 245, the following columns are provided as the target sites of the findings: “endothelial cells” representing corneal endothelial cells; “endothelial front” representing the front surface of the corneal endothelium (boundary surface with the Descemet's membrane) The “rear endothelium” representing the posterior surface of the corneal endothelium (interface with the anterior chamber); the “endothelial thickness” representing the thickness of the corneal endothelium; the “Desme membrane”; the “Desme film thickness” representing the thickness of the Desme membrane; “Cornea thickness” representing the thickness of the cornea Ec. Furthermore, as a finding, a column of “binocular / unicular” indicating whether each disease generally occurs in both eyes or one eye is provided.

Note that the columns provided in the findings are not limited to the above. For example, other parts of the anterior segment (corner angle, etc.), genetic information (name of disease affected by parent, etc.), subject information (gender, age, medical history, medication history, presence / absence of wearing contact lenses, etc.) ) And the like, it is possible to set columns appropriately according to the disease name to be identified.

In addition, the following columns are provided for disease names: “droplet cornea”; “Fuchs” representing Fuchs corneal endothelial dystrophy; “CHED” representing congenital hereditary corneal endothelial dystrophy; “PPCD” representing “Position Corneal Vessel” “PCV”; “IEC” representing iris-corneal endothelial syndrome; “trauma at delivery”; “congenital glaucoma”. The column provided for the disease name is not limited to the above, and any disease name related to the anterior segment (particularly the corneal endothelium) can be provided.

Here, while briefly explaining the corneal endothelium and Descemet's membrane, each of the above diseases will be explained briefly. The findings associated with each disease name are based on the following explanation and clinical results.

The cell density of corneal endothelial cells is 5000 to 6000 cells / mm ^{2 at} the time of birth and about 3000 cells / mm ² at the age of 2 years. In the twenties, the cell density is about 3000 cells / mm ² , the coefficient of variation (CV value) is around 0.25, and the appearance ratio of hexagonal cells (hexagon cell rate) is 65 to 70%. In the 70s, the cell density is about 2500 cells / mm ² , the CV value is around 0.30, and the hexagonal cell rate is around 60%. In addition, these values are significantly different in long-term contact lens wearers compared to healthy people of the same age. Moreover, it is thought that CV value and a hexagonal cell rate have a correlation with the function of a corneal endothelium. In addition, corneal turbidity is considered to occur due to malfunction when the cell density is 500 cells / mm ² or less. At present, the only treatment for turbidity is corneal transplantation.

The following is known about the Desme membrane. First, the thickness of ABZ is about 3 μm and does not change throughout life. On the other hand, PNBZ increases in thickness with age (for example, approximately 6 μm at 60 years old), which is thought to be produced by the endothelium after the embryonic period. By determining the abnormality of ABZ and PNBZ, it can be estimated whether the abnormality of the corneal endothelium is congenital or acquired. This estimation process can be carried out, for example, by determining to which layer the morphological abnormality (irregularity) such as unevenness or tearing of the layer extends.

Explain clinical findings. When observed with a vertical tomographic image, the corneal endothelium is observed as a smooth surface with a slightly steeper curvature than the corneal epithelium. In addition, when the surface of the corneal endothelium is irregular, or when adhesion of precipitate (rear deposits) or iris pigment (iris pigment) is recognized, it is considered that there is some cause for damaging the corneal endothelium. At this time, PCV is also an important finding.

Surface irregularities can be determined from, for example, the amount of displacement from the base curve of the surface. The base curve will be described with reference to FIG. The surface of the corneal endothelium (anterior surface or posterior surface) is originally drawn to create a smooth arc in a vertical tomogram. On the other hand, the surface U shown in FIG. 4 has irregular portions V such as irregularities and wrinkles. The base curve BC is an estimation of the original shape (smooth arc shape) of the surface U, that is, the shape when the irregular portion V does not exist.

The base curve BC is set, for example, as follows: By analyzing the pixel values of the pixels constituting the tomographic image as described above, the boundary region (plane U) between the corneal endothelium region and its neighboring region is determined. Extracting; calculating a differential coefficient (primary differential, secondary differential, etc.) at each point of the surface U; obtaining a feature point (vertex, inflection point, etc.) on the surface U based on the calculated differential coefficient; An irregular portion V is identified based on the number and position of these feature points; an arcuate region is obtained by extending a smooth arc-shaped portion excluding the identified irregular portion V. This arcuate region is the base curve BC.

The method of obtaining the base curve BC is not limited to the above, and for example, by pattern matching or difference processing between a template image imitating the original cross-sectional shape of the surface U and an image of the surface U extracted from the tomographic image. It is also possible to obtain the base curve BC. The base curve BC can be obtained in the same manner for irregularities caused by the presence of deposits.

Also, when obtaining an irregularity of the two-dimensional image (curved surface image) of the surface U depicted in the three-dimensional image and the base curve BC, the same processing, that is, using a two-dimensional template image, 2 It is possible to use a dimensional differential coefficient. In addition, fraud and base curves can be obtained for surfaces other than the corneal endothelium by the same process.

In addition, when there is an abnormality in the corneal endothelium, the Desme membrane is often accompanied by an abnormality. Therefore, in diagnosis of the corneal endothelium, it is important to refer to not only the corneal endothelium itself but also the state of the Desme membrane. In particular, the presence or absence of wrinkles of Descemet's membrane, retrocorneal membrane (a membrane material on the back surface), guttata (spots) or the like is important. These abnormalities can be detected by the amount of displacement from the base curve of the front and back surfaces of the Descemet's membrane and corneal endothelium.

In the diagnosis of corneal endothelium, unilateral or bilateral abnormalities are important information. In general, in the case of a binocular abnormality, primary is strongly suspected, and in the case of a secondary disease, it is mostly a unilateral abnormality.

Also, the presence or absence of corneal parenchymal lesions and inflammation of the anterior chamber is also important information. In the absence of corneal parenchymal edema or anterior chamber inflammation, there are suspicions of primary minor cases, in particular, corneal corneal, Fuchs corneal endothelial dystrophy, posterior polymorphic dystrophy, and Posterior Corneal Vesicle.

Droplet cornea is a primary and binocular disease, such as the local accumulation of collagen-like substances between the Descemet's membrane and the corneal endothelium (frontal corneal endothelium) and the ridge-like projections on the posterior surface of the corneal endothelium. Findings are seen. In addition, corneal endothelial cells are often irregularly shaped, and large and small (variation in size) are observed. On the other hand, the corneal thickness and the number of corneal endothelial cells (cell density) are often normal.

Fuchs corneal endothelial dystrophy is a primary, binocular, autosomal dominant hereditary disease that is common in middle-aged women. Connective tissue of about 4-5 μm is produced in corneal endothelial cells, and the thickness of the Descemet's membrane increases (about 8-10 μm). Observations include the following: Spider-like protrusions into the anterior chamber; layered rods; rods in layered connective tissue; layered bonds without rods Organization. Atheromatous processes become thin and irregular by squeezing corneal endothelial cells. This can be grasped by irregularities in the front and back surfaces of the Descemet's membrane and corneal endothelium and the thickness of the Descemet's membrane and corneal endothelium. In addition, since the size of corneal endothelial cells becomes remarkable and the original hexagonal shape is lost, it is possible to determine an abnormality based on the coefficient of variation, the hexagonal cell rate, and the like.

Congenital hereditary corneal endothelial dystrophy is a primary disease, and in its findings, a beaded white line is seen in the posterior Descemet's membrane and corneal endothelial cells. In the corneal endothelium, there are a portion where the cell is deficient and a portion which is thinned and contains pigment granules and looks like corneal epithelial cells. Such an abnormality can be grasped, for example, by measuring a displacement amount or thickness from the base curve of the front and back surfaces of the Descemet's membrane or corneal endothelium. In addition, according to the anterior ocular segment observation apparatus 100, unlike a specular microscope, it is possible to distinguish between a defect and a protrusion.

Posterior polymorphic dystrophy is a primary and binocular disease. About 2 to 20 blister-like small circular lesions are gathered, and a grayish white circle halo surrounds them. In addition, there are cases where blisters are not obvious and map-like lesions and dense grayish white turbidity occur, and there are wide undulated strip-like lesions and thickening of the Descemet's membrane. Such an abnormality can be grasped by measuring the amount of displacement and the thickness of the Descemet's membrane and corneal endothelium from the front and back base curves.

Posture Corneal Vesicle is a primary and unilateral disease that is usually asymptomatic and often found by ophthalmic medical examination. Findings include vesicles and band-like lesions on the posterior surface of the Descemet's membrane and corneal endothelium. Most zonal lesions run horizontally. Such an abnormality can be grasped by measuring the amount of displacement and the thickness of the Descemet's membrane and corneal endothelium from the front and back base curves.

Iris-corneal endothelial syndrome is a disease which is primary and unilateral and has abnormalities in the corneal endothelium, anterior chamber corner and iris. The findings include degeneration of corneal endothelial cells, a decrease in the number of corneal endothelium, and a loss of corneal endothelium, and a thick layered tissue (PCL) of collagen-like substance produced from the corneal endothelial cells is observed on the rear surface of the Descemet's membrane. Such an abnormality can be grasped by measuring the amount of displacement and the thickness of the Descemet's membrane and corneal endothelium from the front and back base curves.

Delivery trauma is a secondary disease that results in rupture of the Descemet's membrane and corneal endothelium due to pressure on the cornea during delivery. As a finding, rupture of a strip-like desme film that runs linearly is observed. Such findings are similar to those of congenital glaucoma, but in congenital glaucoma, rupture of the Descemet's membrane is binocular and not linear.

The disease information 245 is set based on the findings of various diseases as described above. At that time, as described above, a displacement amount from the base curve, a threshold value such as a thickness, and an allowable range are determined and recorded in the disease information 245. In addition, a lesion mode (description mode in an image) based on the above findings is determined and recorded in the disease information 245. In the disease information 245 shown in FIG. 3, “irregular, large / small, normal number of cells” and the like are recorded in the columns corresponding to “droplet cornea” and “endothelial cells”. In the columns corresponding to “Fuchs” and “endothelial cells”, “connective tissue (4 to 5 μm), stratified rod, stratified tissue, hexagonal cell rate is low” and the like are recorded. In the column corresponding to “Fuchs” and “Desme film thickness”, “thickening (8 to 10 μm)” or the like is recorded. In the column corresponding to “CHED” and “endothelial cell”, “there is a defective part, and there are epithelial cell-like findings due to pigment granules” and the like are recorded. In the column corresponding to “CHED” and “Desme film”, “beaded bead-like white line” is recorded. In the column corresponding to “PPCD” and “endothelial cells”, “unclear bullous lesions, map-like lesions, turbidity, zonal lesions” and the like are recorded. In the column corresponding to “PCV” and “back surface of endothelium” and the column corresponding to “PCV” and “Desme membrane”, “bullous lesion, band lesion” and the like are recorded, respectively. In the column corresponding to “IEC” and “endothelial cell”, “cell degeneration, number reduction, defect” and the like are recorded. Further, “PCL (collagen-like substance)” is recorded in the column corresponding to “IEC” and “Desme membrane”. In the column corresponding to “trauma during delivery” and “desme membrane”, “rupture (straight, strip)” or the like is recorded. In the column corresponding to “congenital glaucoma” and “desme membrane”, “rupture (non-linear)” or the like is recorded.

(Abnormality judgment unit)
The abnormality determining unit 246 analyzes the image region specified by the image region specifying unit 242, and determines an abnormality of the corneal endothelium. This process may determine whether or not there is an abnormality, or may determine the degree of abnormality. The abnormality determination unit 246 and the storage unit 244 constitute an example of the “determination unit” of the present invention.

The abnormality determination unit 246 includes a boundary region specifying unit 247, a base curve specifying unit 248, a boundary shape analyzing unit 249, a layer region specifying unit 250, a layer region analyzing unit 251, a cell region specifying unit 252, a cell state analyzing unit 253, A change analysis unit 254 and a disease specifying unit 255 are included.

(Boundary area identification part, base curve identification part, boundary shape analysis part)
When the corneal endothelium region is specified by the image region specifying unit 242 for a plurality of tomographic images (particularly vertical tomographic images), the boundary region specifying unit 247, the base curve specifying unit 248, and the boundary shape analyzing unit 249 Abnormality of the corneal endothelium is determined based on the image. Hereinafter, this determination process will be described.

The boundary region specifying unit 247 specifies a boundary region in each vertical tomographic image corresponding to the boundary surface of the corneal endothelium of the cornea Ec. The boundary area specifying unit 247 is an example of the “boundary area specifying means” of the present invention.

In order to specify the boundary region, the boundary region specifying unit 247 analyzes the pixel values of the pixels constituting the image region including the corneal endothelium region specified by the image region specifying unit 242 and its neighboring region. In this analysis processing, for example, by using the analysis result described above by the image region specifying unit 242, an image region (endothelial front boundary) corresponding to the front surface of the corneal endothelium (boundary surface with the Descemet's membrane) in each vertical tomographic image. Region) or an image region (endothelial posterior boundary region) corresponding to the posterior surface (boundary surface with the anterior chamber) is specified.

At this time, both the endothelial front boundary region and the endothelial rear boundary region may be specified, or only one of them may be specified. The specified boundary region is set in advance according to, for example, an abnormality detection target. Moreover, you may make it specify both or one side always.

The base curve specifying unit 248 and the boundary shape analyzing unit 249 determine abnormality of the boundary region based on the shape of the boundary region specified by the boundary region specifying unit 247. An example of this abnormality determination process will be described.

When the surface U as shown in FIG. 4 is specified as the boundary region, the base curve specifying unit 248 determines the base curve BC based on the surface U. The process for obtaining the base curve BC has been described above. The boundary shape analysis unit 249 detects the unevenness (irregular portion V) of the surface U with respect to the base curve BC. The base curve specifying unit 248 and the boundary shape analyzing unit 249 constitute an example of the “unevenness detecting unit” of the present invention.

Further, the boundary shape analysis unit 249 obtains a displacement amount of the irregular portion V with respect to the base curve BC. This displacement amount is, for example, an irregular portion V with respect to the base curve BC, such as a maximum separation distance between the base curve BC and the irregular portion V, a width of the irregular portion V, an area of an image region surrounded by the base curve BC and the irregular portion V, and the like. This is a physical quantity that characterizes the displacement of.

The boundary shape analysis unit 249 determines whether the amount of displacement is within a predetermined allowable range. The boundary shape analysis unit 249 determines that the boundary region has no abnormality if the displacement amount is within the allowable range, and determines that there is an abnormality if the amount of displacement is outside the allowable range.

Also, the boundary shape analysis unit 249 can determine the degree of abnormality in the boundary region based on the absolute value of the displacement amount, the displacement of the displacement amount with respect to a predetermined allowable range or threshold value, and the like.

(Layer region identification part, Layer region analysis part)
When the corneal endothelium region is specified by the image region specifying unit 242 for each of a plurality of tomographic images (particularly vertical tomographic images), the layer region specifying unit 250 and the layer region analyzing unit 251 Based on the thickness of the layer region in each vertical tomographic image corresponding to the predetermined layer, the abnormality of the predetermined layer and further the abnormality of the corneal endothelium are determined. Here, the abnormality of the layer region is related to the abnormality of the corneal endothelium.

In order to perform this abnormality determination, the layer region specifying unit 250 specifies a layer region in each vertical tomographic image corresponding to a predetermined layer of the anterior segment. The layer region specifying unit 250 is an example of the “layer region specifying unit” of the present invention.

In order to identify the layer region in the vertical tomographic image, the layer region identifying unit 250 analyzes the pixel values of the pixels constituting the image region including the corneal endothelium region identified by the image region identifying unit 242 and its neighboring region. Do. In this analysis processing, for example, by using the analysis result described above by the image region specifying unit 242, a layer region corresponding to a corneal endothelium region and a Descemet's membrane (all layers, ABZ layer, PNBZ layer) in each vertical tomographic image. , Layer regions such as the cornea (all layers) are identified. The layer region is specified, for example, by specifying its front and back surfaces.

At this time, a layer region corresponding to one layer may be specified, or a layer region corresponding to each of two or more layers may be specified. The specified layer region is set in advance according to, for example, an abnormality detection target. Further, the predetermined layer region may be always specified.

The layer region analysis unit 251 obtains the thickness of the identified layer region. The thickness of the layer region can be calculated based on, for example, the interval between adjacent pixels based on the OCT image measurement magnification obtained in advance and the number of pixels between the front surface and the rear surface of the layer region. It is also possible to obtain the thickness by calculating the difference between the depth position of the front boundary and the depth position of the rear boundary of the layer region. Further, the difference between the position of the reference mirror 9 when the horizontal tomographic image including the pixels on the front boundary is acquired and the position of the reference mirror 9 when the horizontal tomographic image including the pixels on the rear boundary is acquired is calculated. By doing so, the thickness of the layer region can also be obtained.

Furthermore, the layer region analysis unit 251 determines whether the obtained layer region thickness is within a predetermined allowable range. Then, the layer region analysis unit 251 determines that the predetermined layer (and thus the corneal endothelium) has no abnormality if the thickness is within the allowable range, and determines that there is an abnormality if the thickness is outside the allowable range.

Further, the layer region analysis unit 251 can also determine the degree of abnormality in the predetermined layer based on the absolute value of the thickness, the deviation of the thickness with respect to a predetermined allowable range or threshold value, and the like.

(Cell area identification part, cell state analysis part)
When the corneal endothelium region is specified by the image region specifying unit 242 for each of a plurality of tomographic images (particularly horizontal tomographic images), the cell region specifying unit 252 and the cell state analyzing unit 253 detect abnormalities of the corneal endothelium (cells). judge.

For this purpose, the cell region specifying unit 252 analyzes the pixel values of the pixels that form the image region including the corneal endothelium region specified by the image region specifying unit 242 and its neighboring regions, and configures the corneal endothelium of the eye E to be examined. A plurality of cell regions in the corneal endothelial region corresponding to the corneal endothelial cell to be identified are specified. This process can be executed in the same manner as the cell area extraction process described above by the image area specifying unit 242. In addition, when the cell region has already been extracted by the image region specifying unit 242, the cell region specifying unit 252 can use the result of this extraction processing. The cell area specifying unit 252 is an example of the “cell area specifying means” of the present invention.

The cell state analyzing unit 253 analyzes the state of the corneal endothelial cell based on the plurality of cell regions specified by the cell region specifying unit 252 and thereby determines the abnormality of the corneal endothelium. Hereinafter, an example of the abnormality determination process will be described.

The cell state analyzing unit 253 first obtains evaluation information on the state of the corneal endothelial cell based on the plurality of cell regions specified by the cell region specifying unit 252. In this processing, for example, evaluation information similar to that of the specular microscope, that is, cell density, maximum cell area, minimum cell area, average cell area, standard deviation of area, coefficient of variation of cell area, appearance rate of hexagonal cell region A histogram of the cell area is required.

The cell density represents the number of cell regions included in a predetermined area (1 mm ² ). For example, the cell density can be set based on a plurality of specified cell regions and an image region of a predetermined area in a horizontal tomogram (magnification). ).

The maximum cell area represents the maximum value of the areas of the plurality of specified cell regions, and can be obtained, for example, by calculating the area of each cell region and comparing the size.

The minimum cell area represents the minimum value of the areas of the plurality of specified cell regions, and can be obtained in the same manner as the maximum cell area, for example.

The average cell area is an average value of the areas of a plurality of specified cell regions, and can be calculated by a normal statistical calculation.

The area standard deviation is a standard deviation of areas of a plurality of specified cell regions, and can be calculated by a normal sugar solution calculation.

The variation coefficient of the cell area is a statistic (the CV value described above) indicating a relative error with respect to the average cell area, and is obtained by dividing the area standard deviation by the average cell area.

The appearance rate of the hexagonal cell region is the aforementioned hexagonal cell rate. For example, it is determined whether each identified cell region is a hexagonal shape, and the number of the cell regions determined to be hexagonal shapes is divided by the total number. Can be calculated.

The cell area histogram is information representing the frequency of each cell area and can be obtained by normal statistical calculation.

In an actual examination, at least one of the above evaluation information is required according to the type of disease. It is also possible to obtain other types of evaluation information. Such a cell state analysis unit 253 constitutes an example of the “evaluation means” of the present invention.

Furthermore, the cell state analysis unit 253 determines the abnormality of the corneal endothelium based on the calculated evaluation information. Therefore, for example, an allowable range for each piece of evaluation information is set in advance (stored in the storage unit 244), and the cell state analysis unit 253 determines that each piece of evaluation information obtained based on a plurality of cell regions It is determined whether it is included in the allowable range. When it is determined that it is included, it is determined that there is no abnormality, and when it is determined that it is not included, it is determined that there is an abnormality. It is also possible to determine the degree of abnormality based on the deviation of the evaluation information with respect to the allowable range.

(Aging analysis unit)
The determination result obtained by the abnormality determination unit 246 is stored in the storage unit 244 in association with, for example, a patient ID, left and right eye information, and examination date information. Here, the left and right eye information is information for identifying whether the eye to be examined is the left eye or the right eye.

Whether the eye E to be examined is the left eye or the right eye (right and left eye information) may be manually input by an operator, for example, or when the apparatus optical system moves on the stage, the optical system You may determine automatically based on the position of the left-right direction. The patient ID may be manually input by an operator or may be automatically acquired with reference to the subject's electronic medical record, for example. The inspection date information may be manually input by an operator or may be automatically acquired with reference to the timekeeping function of the computer 20, for example.

When the abnormality of the corneal endothelium is determined for the eye E, the temporal change analysis unit 254 searches the storage unit 244 for past determination results of the eye E. In this search process, for example, the temporal change analysis unit 254 selects a determination result related to the subject by collating the patient ID, and determines the determination result of the eye E from the selected determination results based on the left and right eye information. select.

Furthermore, the temporal change analysis unit 254 selects the determination result obtained in the previous examination based on the examination date / time information from the selected judgment result of the eye E. In this process, for example, the latest date / time is specified from the examination date / time information associated with the past determination result of the eye E, and the determination result associated with the examination date / time information representing the latest date / time is selected. Is.

It should be noted that the selected determination result is not limited to that of the previous inspection, and may be any past determination result. It is also possible to select two or more determination results.

The temporal change analysis unit 254 compares the new abnormality determination result obtained in this examination with the past determination result retrieved from the storage unit 244, and based on the result, the corneal endothelium of the eye E to be examined is compared. Find time-varying information. The time-dependent change information is information representing a time-dependent change in the state of the corneal endothelium (for example, the presence / absence or degree of abnormality). The process for obtaining the temporal change information is executed as follows, for example.

When one past determination result is retrieved, the temporal change analysis unit 254 obtains, for example, a new change in the determination result with respect to the past determination result and uses it as the temporal change information.

Further, when two or more past determination results are retrieved, the temporal change analysis unit 254 creates, for example, a graph representing the temporal changes of a plurality of past determination results and new determination results, and uses them as the temporal change information. . It is also possible to designate an arbitrary region in each OCT image to be analyzed for change over time based on positional information such as an abnormal part and to calculate the amount of change over time of various parameters in the specified region. At this time, a temporal change amount may be obtained for the entire measurement region of the OCT image by sequentially designating a region of a predetermined unit size set in advance for each OCT image. Furthermore, displaying information (such as a message) that calls attention when the calculated amount of change over time is equal to or greater than a predetermined threshold may lead to early detection of an abnormality.

As described above, information (position information) indicating the position can be given to the detected abnormal part. By referring to this position information, it is possible to compare the same parts as described above, and it is possible to detect a change in the degree of abnormality, a movement of a place, and the like. Further, by comparing such identical parts, a newly appearing abnormality can be detected, or the disappearance of an abnormality existing in the past can be detected, so that more detailed abnormality detection can be performed.

(Disease Identification Department)
As described above, the disease information 245 is stored in the storage unit 244 in advance (see FIG. 3). Based on the disease information 245, the disease identification unit 255 identifies a disease name corresponding to the determination result of the abnormality of the corneal endothelium. The specified disease name is a candidate for a disease that is suspected of having the eye E to be examined.

An example of processing executed by the disease identification unit 255 will be described. The disease information 245 is information that associates a disease name with an abnormality of the corneal endothelium. As described above, the abnormality determination unit 246 determines whether or not there are various abnormalities of the corneal endothelium. For example, the abnormality determination unit 246 includes an abnormality of the corneal endothelial cell, an abnormality of the front or rear surface of the corneal endothelium, an abnormality of the thickness of the corneal endothelium (endothelium thickness), an abnormality of the Desme film, and a thickness of the Desme film (Desme film thickness). Abnormalities, corneal thickness (corneal film thickness) abnormality, and the like are determined. It is also possible to determine whether the abnormality is binocular or unilateral by examining both eyes of the subject.

The disease identification unit 255 collates the abnormality determination result by the abnormality determination unit 246 with the findings corresponding to each disease name in the disease information 245, and determines the disease name that may cause the corneal endothelium of the eye E to be affected. Identify.

At this time, the disease name may be specified when determination results for all findings are applicable, or the disease name may be specified when determination results for some findings are applicable. .

For example, findings corresponding to the droplet cornea include binocular, irregular corneal endothelial cells, collagen-like substances on the front surface of the corneal endothelium, ridges on the posterior surface of the corneal endothelium, and normal corneal thickness. At this time, when determination results corresponding to all of these are obtained, “droplet cornea” can be specified as a disease name that may be affected. In addition, when a determination result corresponding to only a part of these findings is obtained, “droplet cornea” may be specified as a disease name that may be affected.

In addition, it is possible to determine the possibility of morbidity depending on how many findings among a plurality of findings corresponding to a certain disease name are obtained. For example, when a determination result corresponding to one or two of the findings corresponding to the keratoconus is obtained, it is determined that “the possibility of morbidity is low”, and a determination result corresponding to three is obtained. If it is determined that the possibility of morbidity is moderate, and if a determination result corresponding to four or five is obtained, it can be determined that the possibility of morbidity is high. It is also possible to weight each finding and determine the possibility of morbidity by the total value of the weights.

The control unit 21 causes the display unit 22 to display the determination result by the abnormality determination unit 246. At this time, items determined to be abnormal and their contents may be individually displayed. It is also possible to display an anterior image (tomographic image, three-dimensional image, etc.) of the eye E. In particular, together with the abnormality determination result, the image used for the abnormality determination can be displayed. It is also possible to display abnormal time-dependent information, the specified disease name, and the like. The doctor makes the final diagnosis, and the displayed information has the meaning of diagnosis support.

[Action / Effect]
The operation and effect of the anterior segment observation apparatus 100 configured as described above will be described.

The anterior ocular segment observation apparatus 100 forms a three-dimensional image of the anterior ocular segment of the eye E using full field type OCT. Further, the anterior ocular segment observation apparatus 100 analyzes the formed three-dimensional image, identifies a corneal endothelium region corresponding to the corneal endothelium of the anterior ocular segment, and includes an image including the identified corneal endothelium region and its neighboring region. The region is analyzed to determine abnormalities of the corneal endothelium.

The types of abnormalities determined by the anterior ocular segment observation apparatus 100 include abnormalities at the interface of the corneal endothelium, abnormalities in the corneal layer, abnormalities in corneal endothelial cells, and the like. Further, according to the anterior ocular segment observation apparatus 100, it is also possible to obtain information on temporal changes in abnormalities of the corneal endothelium, and specify a disease name that may cause the eye E to be affected based on the abnormality determination result. You can also.

According to such an anterior ocular segment observation apparatus 100, since full-field type OCT is used, there is no problem with specular reflection light like a specular microscope or the like, and therefore a part of the image falls out black. There is no inconvenience.

In addition, according to the anterior ocular segment observation device 100, unlike a specular microscope, etc., it is configured to detect reflected light that travels in a direction opposite to the direction of illumination light irradiation, so that parts existing at different depth positions are shifted in the horizontal direction. There is no inconvenience of being observed.

Furthermore, according to the anterior ocular segment observation apparatus 100, it is possible to determine abnormality of the corneal endothelium based on the image area including the corneal endothelium area and its vicinity area. Therefore, it is possible to automatically determine the presence or absence and degree of abnormality of the corneal endothelium, and it is possible to improve the accuracy of the anterior ocular segment observation and the efficiency.

According to such an anterior ocular segment observation apparatus 100, detailed observation of the state of the anterior segment of the eye E, particularly the corneal endothelium and the vicinity thereof (Desme's membrane, anterior chamber, etc.) is possible.

[Modification]
The content described above is merely an example of the anterior segment observation apparatus according to the present invention. A person who intends to implement the present invention can make arbitrary modifications within the scope of the gist of the present invention.

As described above, the PNBZ layer of the Descemet's membrane can be used to determine whether the abnormality (disease) of the corneal endothelium is congenital or acquired. An example of this determination process will be described.

For each abnormality (disease name), thickness threshold information for distinguishing between congenital and acquired is created in advance and stored in the storage unit 244. This threshold information can be created based on a large number of clinical data, for example.

When it is determined that an abnormality of the corneal endothelium exists, the abnormality determination unit 246 analyzes the pixel values of the pixels constituting the image region including the corneal endothelium region specified by the image region specifying unit 242 and generates the PNBZ layer. An image region in each corresponding tomographic image is specified. Further, the abnormality determination unit 246 obtains the thickness of the image area corresponding to the PNBZ layer, and determines whether the abnormality is congenital or acquired based on the thickness. This determination process is executed by comparing the obtained thickness with threshold information.

According to this modification, it is possible to automatically estimate whether the detected abnormality is congenital or acquired, so that it is possible to improve the accuracy of the anterior segment observation, improve the efficiency, etc. Detailed observation of the state is possible. In addition, it is possible to use the acquired determination result of congenital or acquired for various processes (for example, the process which specifies a disease name) in said embodiment.

The anterior ocular segment observation apparatus according to the present invention may be configured to determine an abnormality of the corneal endothelium for each of the tomographic images in a plurality of cross sections of the three-dimensional image and display the tomographic image determined to be abnormal.

In this modification, a three-dimensional image of the anterior segment is formed by the same optical system, changing means, and forming means as in the above embodiment.

The specifying means of this modification forms tomographic images (horizontal tomographic images and vertical tomographic images) at a plurality of cross sections of this three-dimensional image in the same manner as the image region specifying unit 242 of the above embodiment. Furthermore, this specifying means performs an analysis process similar to that of the image region specifying unit 242 to each tomographic image, and specifies a corneal endothelium region corresponding to the corneal endothelium.

The determination means of the present invention determines an abnormality of the corneal endothelium by analyzing an image region including the specified corneal endothelium region and its neighboring region for each tomographic image. This process is executed in the same manner as the abnormality determination unit 246 of the above embodiment.

Thereby, the plurality of tomographic images are divided into a group of tomographic images determined to be abnormal and a group of tomographic images not determined to be abnormal. This grouping may be performed on the basis of the presence or absence of abnormality, or may be performed on the basis of the degree of abnormality. That is, the former is divided into a group of tomographic images determined to have an abnormality and a group of tomographic images determined to have no abnormality, and the latter is determined to have an abnormality exceeding a predetermined degree. The tomographic image group is divided into a group of tomographic images determined to have an abnormality of a predetermined level or less (including those determined to have no abnormality).

The group of tomographic images determined to be abnormal is displayed on the display means. This display means is the same as the display unit 22 in the above embodiment. The tomographic images belonging to the group are displayed on the display means by the same microprocessor as the control unit 21.

At this time, all tomographic images determined to be abnormal may be displayed at a time, or a part (one or more) of tomographic images may be displayed. In the former case, thumbnails of all tomographic images may be created and displayed. In the latter case, the tomographic images may be sequentially switched and displayed in a slide show format, or the tomographic images may be switched and displayed in accordance with an operator instruction (using the operation unit 23).

According to this modification, similarly to the above-described embodiment, there is no inconvenience that a part of the image is blackened out due to a problem with specular reflection light, and parts existing at different depth positions are observed shifted in the horizontal direction. There is no inconvenience.

Furthermore, according to this modified example, the corneal endothelium is determined to be abnormal for a plurality of tomographic images, and the tomographic image determined to be abnormal is displayed, so that the examiner is determined to have an abnormality. Can focus on the affected area. Thereby, it is possible to improve the accuracy and efficiency of anterior segment observation. Thus, according to this modification, detailed observation of the state of the anterior segment of the eye to be examined, particularly the corneal endothelium and the vicinity thereof, is possible.

In the above-described embodiment, the configuration capable of determining the abnormality of the boundary surface of the corneal endothelium, the abnormality of the corneal layer, and the abnormality of the corneal endothelial cell has been described. However, at least one of these abnormalities can be determined. It is also possible.

Further, in the above-described embodiment, it is possible to obtain time-dependent change information of corneal endothelium abnormality or to specify a disease name that may cause the subject eye, but only one of these processes Can be configured to be executable, or a configuration that does not execute both of these processes can be employed.

In addition, regarding abnormalities in which deposits accumulate on the posterior surface of the cornea, the conventional technique could not identify the type of deposit by image observation, so a predetermined treatment instrument was inserted into the eyeball, and the deposit was collected from the anterior chamber. Were cultured and observed with an optical microscope or the like. Such a method places a heavy burden on the patient, and it takes a long time to specify the type.

According to the anterior ocular segment observation device according to the present invention, it is possible to solve such a problem. Therefore, for each type of deposit, the fine structure of the deposit (features such as shape, size, and arrangement in the OCT image) and the accumulation mode of the deposit are converted into data in advance and stored as deposit information. This deposit information is information that associates the type of deposit with the fine structure and accumulation mode of the deposit.

In an actual examination, a three-dimensional image of the anterior segment of the eye to be examined is acquired, an image area corresponding to the posterior corneal surface (rear corneal endothelium) is specified in the three-dimensional image, and this image area corresponds to a deposit. It is determined whether there is an image area (deposition object area) to be performed. This determination process is executed by the method using the base curve described in the above embodiment, for example.

If there is a deposit area, the pixel values of the pixels included in the deposit area are analyzed to determine the fine structure and accumulation mode of the deposit, and the type of deposit based on the fine structure and the deposit information Is identified.

By executing such processing, the type of deposit can be specified by image observation, so that the burden on the patient can be greatly reduced and the type of deposit can be specified in a short time.

The anterior ocular segment observation apparatus can be configured to display a tomographic image determined to be abnormal among tomographic images in a plurality of cross sections of a three-dimensional image. The anterior ocular segment observation apparatus according to this modification forms, for example, a three-dimensional image of the anterior ocular segment in the same manner as in the above embodiment.

Next, the anterior ocular segment observation apparatus according to this modified example identifies a corneal endothelium region by analyzing tomographic images at a plurality of cross sections of the three-dimensional image of the anterior ocular segment. This process is executed, for example, in the same manner as the image area specifying unit 242 of the above embodiment.

Subsequently, the anterior ocular segment observation apparatus according to this modification determines an abnormality of the corneal endothelium by analyzing the image region including the specified corneal endothelium region and its neighboring region for each tomographic image of the three-dimensional image. This process is executed, for example, in the same manner as the abnormality determination unit 246 of the above embodiment.

Furthermore, the anterior ocular segment observation apparatus according to this modification displays a tomographic image determined to be abnormal among the plurality of tomographic images. These tomographic images are displayed on the display unit 22 by the control unit 21, for example.

According to such a modification, since full-field type OCT is used, there is no problem with specular reflection light, and there is no inconvenience that part of the image is blackened out. Moreover, according to this modification, since the reflected light that travels in the direction opposite to the illumination light irradiation direction is detected, there is no inconvenience that parts existing at different depth positions are observed shifted in the horizontal direction. Further, according to this modified example, the corneal endothelium is determined to be abnormal for a plurality of tomographic images, and the tomographic images determined to be abnormal are displayed. It is possible to focus on the site determined to be present, thereby improving the accuracy of the anterior ocular segment observation and improving the efficiency. Therefore, according to this modification, detailed observation of the state of the anterior eye portion of the eye to be examined, particularly the corneal endothelium and its vicinity is possible.

In the above embodiment, the polarization characteristic of the reference light R is converted. However, the polarization characteristic of the signal light S may be converted. In that case, a wavelength plate, a polarizing plate, and a glass plate are provided on the optical path of the signal light S.

In the above-described embodiment, the polarization characteristics are converted using the wave plate and the polarizing plate, but any optical element capable of converting the polarization characteristics can be used. In the above configuration, the reference light R is converted into circularly polarized light. However, the reference light R or the signal light S can be converted into arbitrary polarization characteristics (linearly polarized light, elliptically polarized light). is there.

In the above embodiment, the dispersion generated in both arms of the interferometer is corrected using a glass plate, but a dispersion correcting optical element such as an optical element of any form capable of correcting the dispersion is applied. Is also possible.

In the above embodiment, the interference light L is detected using the

CCDs

16 and 17, but an arbitrary two-dimensional photosensor array such as a CMOS can be applied instead of the CCD.

In the above embodiment, the continuous light of the broadband light is used and the exposure time of the

CCDs

16 and 17 is shortened to deal with the movement of the eye E. However, the present invention is limited to such a configuration. It is not a thing.

For example, an optical chopper is disposed on the optical path of broadband light (continuous light), the broadband light is periodically blocked by the optical chopper to generate pulsed broadband light, and each pulse is detected by the

CCDs

16 and 17. You may do it.

It should be noted that the broadband light blocking period by the optical chopper is about 1 ms, which is longer than the exposure time (about 30 to 50 μs). Therefore, it is desirable to control the exposure time when the eye E moves quickly.

Further, for example, a wide-band light composed of flash light may be output using a light source such as a xenon lamp, and each flash light may be detected by the

CCDs

16 and 17.

In the above-described embodiment, two detection signals C _A and C _B (C _A ′ and C _B ′) having a phase difference of 90 degrees are acquired by one measurement. / 2 plates may be used to acquire two detection signals with a phase difference of 180 degrees. In this case, the first optical path length and the second optical path length of the reference light R are such that the detection signal obtained by the first detection process and the detection signal obtained by the second detection process have a phase difference of 90 degrees. The distance is set in advance so as to be a proper distance interval. Thereby, four detection signals for every 90 degrees of phase difference can be acquired.

In the above embodiments and the like, the optical image measurement apparatus provided with the Michelson interferometer has been described, but other interferometers such as a Mach-Zehnder type can naturally be employed.

In addition, by providing an optical fiber (bundle) in a part of the interferometer and using it as a light guide member, the degree of freedom in device design can be increased, the device can be made compact, or the arrangement of objects to be measured The degree of freedom can be increased.

The anterior ocular segment observation device according to the present invention may be an arbitrary combination of the configurations of the above-described embodiments and modifications. By combining these configurations, an anterior ocular segment observation apparatus having at least an operation / effect combining the operations / effects peculiar to each configuration is formed.

DESCRIPTION OF SYMBOLS 100 Anterior ocular segment observation apparatus 1 Light source unit 2 Filter 3 Beam splitter 4 Wavelength plate 5 Polarizing plate 6, 15 Reflection mirror 7

Glass plate

8, 11 Objective lens 9 Reference mirror 10 Reference mirror moving mechanism 12 Aperture stop 13 Imaging lens 14

Polarization Beam splitter

16, 17 CCD
20 Computer 21 Control unit 22 Display unit 23 Operation unit 24 Signal processing unit 241 Image forming unit 242 Image region specifying unit 243 Tomographic image forming unit 244 Storage unit 245 Disease information 246 Abnormality determining unit 247 Boundary region specifying unit 248 Base curve specifying unit 249 Boundary shape analysis unit 250 Layer region specifying unit 251 Layer region analyzing unit 252 Cell region specifying unit 253 Cell state analyzing unit 254 Time course analysis unit 255 Disease specifying unit

Claims

An optical system that splits a light beam into signal light and reference light, and generates and detects interference light by superimposing the signal light passing through the anterior segment of the eye to be examined and the reference light passing through the reference optical path; ,
Changing means for changing the optical path length of the reference light and / or the optical path length of the signal light;
Forming means for forming a three-dimensional image of the anterior segment based on the interference light detected by the optical system while changing the optical path length by the changing means;
A specifying unit for analyzing the formed three-dimensional image and specifying a corneal endothelium region corresponding to the corneal endothelium of the anterior segment;
Analyzing the image region including the identified corneal endothelium region and its vicinity region, and determining means for determining abnormality of the corneal endothelium,
An anterior ocular segment observation device comprising:
The specifying means analyzes a tomographic image at a predetermined cross section of the three-dimensional image, and specifies the corneal endothelium region.
The anterior ocular segment observation apparatus according to claim 1.
The specifying means includes tomographic image forming means for forming a tomographic image in a cross section parallel to the incident direction of the signal light with respect to the anterior ocular segment based on the three-dimensional image, and constitutes the formed tomographic image Analyzing the pixel value of the pixel to identify the corneal endothelium region;
The anterior ocular segment observation apparatus according to claim 1.
The determination means includes boundary area specifying means for specifying a boundary area in the tomographic image corresponding to a boundary surface of the corneal endothelium based on a pixel value of a pixel constituting the image area, and the specified boundary Determining the abnormality based on the shape of the region;
The anterior ocular segment observation apparatus according to claim 3.
The determination unit includes an unevenness detection unit that analyzes an array of pixels constituting the boundary region and detects unevenness on the boundary surface, and determines the abnormality based on the detected unevenness.
The anterior ocular segment observation apparatus according to claim 4.
The determination unit includes a layer region specifying unit that specifies a layer region in the tomographic image corresponding to a predetermined layer of the anterior segment based on a pixel value of a pixel constituting the image region. Determining the thickness of the layer region, and determining the abnormality based on the thickness,
The anterior ocular segment observation apparatus according to claim 3.
When it is determined that an abnormality of the corneal endothelium is present, the determining means determines whether the tomographic image corresponding to the PNBZ layer of the Descemet's membrane of the anterior eye part is based on the pixel values of the pixels constituting the image region. Identifying the image area, determining the thickness of the specified image area, and determining whether the abnormality is congenital or acquired based on the determined thickness,
The anterior ocular segment observation apparatus according to claim 3.
The specifying unit includes a tomographic image forming unit that forms a tomographic image in a cross section orthogonal to the incident direction of the signal light with respect to the anterior segment based on the three-dimensional image, and configures the formed tomographic image Analyzing the pixel value of the pixel to identify the corneal endothelium region;
The anterior ocular segment observation apparatus according to claim 1.
The determination means, based on pixel values of pixels constituting the image area, cell area identification means for identifying a plurality of cell areas in the corneal endothelial area corresponding to the corneal endothelial cells constituting the corneal endothelium; Evaluation means for obtaining evaluation information of the state of the corneal endothelial cell based on the plurality of specified cell regions, and determining the abnormality based on the obtained evaluation information,
The anterior ocular segment observation apparatus according to claim 8.
The evaluation means includes, as the evaluation information, a cell density, a maximum cell area, a minimum cell area, an average cell area, an area standard deviation, a cell area variation coefficient, an appearance rate of a hexagonal cell region, and a cell area histogram. Ask for at least one of
The anterior ocular segment observation apparatus according to claim 9.
The determination unit includes a storage unit that stores a determination result of the abnormality of the corneal endothelium, compares a determination result of a new abnormality for the eye to be examined with the stored determination result of the past, and the comparison result Based on aging information of the corneal endothelium based on,
The anterior ocular segment observation apparatus according to claim 1.
The determination unit includes a storage unit that stores in advance disease information that associates a disease name with an abnormality of the corneal endothelium, and identifies a disease name corresponding to the determination result of the abnormality of the corneal endothelium based on the disease information.
The anterior ocular segment observation apparatus according to claim 1.
An optical system that splits a light beam into signal light and reference light, and generates and detects interference light by superimposing the signal light passing through the anterior segment of the eye to be examined and the reference light passing through the reference optical path; ,
Changing means for changing the optical path length of the reference light and / or the optical path length of the signal light;
Forming means for forming a three-dimensional image of the anterior segment based on the interference light detected by the optical system while changing the optical path length by the changing means;
Analysis means for analyzing tomograms in a plurality of cross sections of the formed three-dimensional image, and specifying means for specifying a corneal endothelium region corresponding to the corneal endothelium of the anterior segment;
For each of the plurality of tomographic images, a determination unit that analyzes the image region including the identified corneal endothelium region and a region near the corneal endothelium region to determine abnormality of the corneal endothelium;
Display means for displaying the tomographic image determined to be abnormal among the plurality of tomographic images;
An anterior ocular segment observation device comprising: