JP2020199106A - Ophthalmologic information processing apparatus, ophthalmologic apparatus, ophthalmologic information processing method, and program - Google Patents

Abstract

To provide a new technology to accurately specify a shape of a tissue of an eye to be examined in a wide range.SOLUTION: An ophthalmologic information processing apparatus includes an acquisition unit, a tissue specification unit, and a specification unit. The acquisition unit acquires a tomographic image of an eye to be examined formed based on scan data acquired by executing OCT measurement for the eye to be examined. The tissue specification unit acquires first shape data indicating a shape of a tissue of the eye to be examined in a first measurement range by subjecting the tomographic image to segmentation processing. The specification unit acquires second shape data indicating a shape of a tissue of the eye to be examined in a second measurement range different from the first measurement range based on the first shape data.SELECTED DRAWING: Figure 1

Description

The present invention relates to an ophthalmic information processing device, an ophthalmic device, an ophthalmic information processing method, and a program.

In recent years, one of the causes of myopia progressing is that the focal point of the peripheral visual field is located on the back side (sclera side) of the retinal surface, so that the retina may extend to the back side and myopia may progress. Has been reported (for example, Non-Patent Document 1).

In order to suppress the progression of such myopia, eyeglasses and contact lenses have been developed that move the focal position of the central visual field to the front side (cornea side) by increasing the refractive power of the peripheral visual field. In addition, refractive surgery such as wavefront-guided LASIK, which is performed based on pre-measured wavefront aberrations, is also performed. Therefore, in such high-performance refraction correction, it is required to accurately measure the refractive power of the peripheral visual field.

In addition, several types of eyeball shapes have been confirmed (for example, Non-Patent Document 2).

There are also types of such eyeball shapes that are common in myopia, and it is considered effective to measure the shape change with the progression of myopia and feed back the measurement results to the coping method for the progression of myopia. Be done.

Earl L. Smith et al. , “Reactive peripheral hyperactive defocus alters central refractive development in infant monkeys”, Vision Research, September 2009, September 2009. 2386-2392 Pavan K Verkicharla et al. , “Eye happe and retinal shape, and their reduction to peripheral refraction”, Optics & Physiological Optics, 32 (2012), pp. 184-199

In a general ophthalmic apparatus, since the fixation target is projected on the measurement optical axis, the refractive power near the fovea centralis of the retina is measured. In this case, it is conceivable to obtain the refractive power of the peripheral visual field from the refractive power in the vicinity of the fovea in consideration of the shape of the tissue in the fundus or the like (shape of the eyeball).

Conventional ophthalmic devices can measure the shape of tissues such as the fundus of the eye using, for example, optical coherence tomography (OCT). However, the range in which the shape of the tissue can be specified is determined by the measurement range of OCT. Generally, the measurement range of OCT is narrower than the range of the above-mentioned desired peripheral visual field. Therefore, the range in which the shape of the structure can be specified with high accuracy becomes narrow, and it is difficult to obtain the refractive power of the peripheral visual field with high accuracy.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a new technique for identifying the shape of a tissue of an eye to be examined with high accuracy in a wide range.

The first aspect of some embodiments is the acquisition unit for acquiring a tomographic image of the eye to be inspected formed based on scan data obtained by performing OCT measurement on the eye to be inspected, and the tomographic image. A tissue identification unit that acquires first shape data representing the shape of the tissue of the eye to be inspected in the first measurement range by performing segmentation processing on the subject, and the first measurement range based on the first shape data. It is an ophthalmologic information processing apparatus including a specific unit for obtaining second shape data representing the shape of the tissue of the eye to be inspected in a different second measurement range.

In the second aspect of some embodiments, in the first aspect, at least a part of the second measurement range overlaps with the first measurement range.

In a third aspect of some embodiments, in the first or second aspect, the second measurement range includes the first measurement range.

In the fourth aspect of some embodiments, in any of the first to third aspects, the specific portion performs extrapolation processing based on the first shape data, whereby the second measurement range. The second shape data in the above is obtained.

In the fifth aspect of some embodiments, in any one of the first to third aspects, the specific portion identifies an approximate curve of the first shape data, and the specified approximate curve is used to identify the approximate curve. 2 Obtain shape data.

In the sixth aspect of some embodiments, in the fifth aspect, the specific unit obtains the second shape data by performing distortion correction processing on the approximate curve in a predetermined range of the second measurement range. Ask.

In the seventh aspect of some embodiments, in any one of the first to third aspects, the specific unit acquires the corrected shape data by performing the actual shape correction on the first shape data. The second shape data is obtained based on the shape of the ellipse obtained by performing the ellipse fitting process on the acquired corrected shape data.

In the eighth aspect of some embodiments, in the sixth aspect, the specific part performs the distortion correction process based on the standard data of the eye.

In a ninth aspect of some embodiments, in any of the first to eighth aspects, the tissue comprises a predetermined layer region in the fundus.

The tenth aspect of some embodiments is based on the refraction power obtained by objectively measuring the eye to be inspected and the second shape data acquired by the specific portion in the eleventh aspect. A calculation unit for calculating the refractive power of the peripheral region of the region including the fovea centralis of the eye to be inspected is included based on a parameter representing the optical characteristics of the eye to be inspected corresponding to the shape of the tissue.

The eleventh aspect of some embodiments includes an optical system for performing the OCT measurement on the eye to be inspected, and an ophthalmologic information processing apparatus according to any one of the first to tenth aspects. It is an ophthalmic device.

The twelfth aspect of some embodiments is an acquisition step of acquiring a tomographic image of the eye to be inspected formed based on scan data obtained by performing OCT measurement on the eye to be inspected, and the tomographic image. On the other hand, the tissue identification step of acquiring the first shape data representing the shape of the tissue of the eye to be inspected in the first measurement range by performing the segmentation process is different from the first measurement range based on the first shape data. This is an ophthalmic information processing method including a specific step of obtaining second shape data representing the shape of the tissue of the eye to be inspected in the second measurement range.

In the thirteenth aspect of some embodiments, in the twelfth aspect, the specific step obtains the second shape data in the second measurement range by performing extrapolation processing based on the first shape data. Ask.

The fourteenth aspect of some embodiments is the refraction power obtained by objectively measuring the eye to be inspected in the twelfth or thirteenth aspect and the second shape acquired in the specific step. A calculation step of calculating the refractive power of the peripheral region of the region including the fovea centralis of the eye to be inspected is included based on the parameters representing the optical characteristics of the eye to be inspected corresponding to the shape of the tissue based on the data.

A fifteenth aspect of some embodiments is a program that causes a computer to perform each step of the ophthalmic information processing method according to any of the twelfth to fourteenth aspects.

It is possible to arbitrarily combine the configurations according to the above-mentioned plurality of aspects.

According to the present invention, it is possible to provide a new technique for identifying the shape of the tissue of the eye to be inspected with high accuracy in a wide range.

It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation of the ophthalmic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation of the ophthalmic apparatus which concerns on embodiment. It is a flowchart which shows an example of the operation of the ophthalmic apparatus which concerns on embodiment. It is a flowchart which shows an example of the operation of the ophthalmic apparatus which concerns on embodiment. It is the schematic for demonstrating the operation of the ophthalmic apparatus which concerns on embodiment.

An example of an ophthalmic information processing apparatus, an ophthalmic apparatus, an ophthalmic information processing method, and an embodiment of a program according to the present invention will be described in detail with reference to the drawings. In addition, the description contents of the document cited in this specification and any known technique can be incorporated into the following embodiments.

The ophthalmic information processing apparatus according to the embodiment acquires a tomographic image of the eye to be inspected. The tomographic image is obtained, for example, by performing optical coherence tomography (OCT) on the eye to be examined using an external ophthalmic apparatus. The ophthalmic information processing device analyzes the acquired tomographic image to obtain shape data (first shape data) representing the shape of a predetermined tissue, and from the obtained shape data of the first measurement range, obtains the first measurement range. It is possible to specify (estimate, predict) shape data (second shape data) in different second measurement ranges. Specifically, the ophthalmic information processing apparatus uses the shape data of the first measurement range in the direction intersecting (specifically, orthogonal to) the measurement optical axis of the optical system for executing OCT as the first measurement range. It is possible to specify the shape data in a different second measurement range (measurement range in the direction intersecting the measurement optical axis). In some embodiments, at least a portion of the second measurement range overlaps the first measurement range. In some embodiments, the second measurement range includes the first measurement range. In some embodiments, the second measurement range is a non-overlapping range with the first measurement range.

Hereinafter, a case where the shape data in the second measurement range including the first measurement range is specified from the shape data in the first measurement range will be mainly described.

In some embodiments, the shape of the layered region is specified by the one-dimensional, two-dimensional, or three-dimensional shape data of the predetermined layered region obtained by analyzing the tomographic image. The ophthalmic apparatus according to some embodiments includes the above-mentioned ophthalmic information processing apparatus and realizes the function of the ophthalmic information processing apparatus.

As described above, the ophthalmic information processing apparatus according to the embodiment obtains the shape of the tissue in the second measurement range different from the first measurement range from the tomographic image or shape data in the first measurement range which is the OCT measurement range. As a result, it becomes possible to identify the shape of the tissue of the eye to be inspected with high accuracy in a range wider than the first measurement range. In some embodiments, the shape data in the first measurement range is subjected to statistical processing (for example, averaging processing) or high-sensitivity component removal processing (low-sensitivity component extraction processing) for misalignment. New shape data representing the true shape of the tissue is obtained, and the shape of the tissue in the second measurement range is obtained from the obtained new shape data.

The shape of the tissue in the eye to be inspected includes the shape of the tissue in the anterior segment of the eye and the shape of the tissue in the posterior segment of the eye. The shape of the tissue in the anterior segment includes the shape of the cornea, iris, crystalline lens, ciliary body, zonule of Zinn, or angle. The shape of the tissue in the posterior segment of the eye includes the shape of the fundus (a predetermined layer region in the fundus). Hereinafter, as the shape of the tissue according to the embodiment, the shape of a predetermined layer region in the fundus will be described as an example. In some embodiments, it is possible to specify the shape of the layered region in the fundus as the shape of the fundus. Layer regions in the fundus include the inner limiting membrane, nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, outer limiting membrane, photoreceptor layer, retinal pigment epithelial layer, and choroid. , Sclera, interface of each layer region, etc. However, the following embodiments can be applied to the shape of any part of the eyeball other than the fundus.

Further, in the following embodiments, the shape data representing the shape of the fundus may be referred to as a shape profile. The shape profile is data representing a change in shape in a predetermined one-dimensional direction, two-dimensional direction, or three-dimensional direction.

The ophthalmologic information processing apparatus according to some embodiments calculates (estimates) the refractive power of the peripheral region outside the region including the fovea centralis in the fundus using the shape of the fundus identified as described above. For example, an ophthalmologic information processing apparatus calculates the refractive power of the peripheral region outside the region including the fovea based on the refractive power of the region including the fovea centralis of the eye to be inspected and the shape of the specified fundus.

The ophthalmic information processing apparatus according to the embodiment can calculate the refractive index in the above region using parameters of an eyeball model such as a known model eye (parameters representing the optical characteristics of the eyeball). Parameters include axial length data, anterior chamber depth data, crystalline lens shape data representing the shape of the crystalline lens (lens curvature, lens thickness, etc.), and corneal shape data representing the shape of the cornea (corneal radius of curvature, corneal thickness, etc.). is there. The ophthalmic information processing device constructs a new eye model by replacing some of the parameters of the eye model with the measured values of the eye to be inspected, and calculates the refractive index of the above region using the constructed new eye model. Is possible. In some embodiments, the above parameters are obtained from an electronic medical record system, a medical image archiving system, an external device, or the like.

The ophthalmic information processing method according to the embodiment includes one or more steps for realizing a process executed by a processor (computer) in the ophthalmic information processing apparatus according to the embodiment. The program according to the embodiment causes a processor to execute each step of the ophthalmic information processing method according to the embodiment.

In the present specification, the “processor” is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (for example, a SPLD (Simple Program)) It means a circuit such as Programmable Logic Device), FPGA (Field Programmable Gate Array)). The processor realizes the function according to the embodiment by reading and executing a program stored in a storage circuit or a storage device, for example.

In this specification, images acquired by OCT may be collectively referred to as OCT images. Further, the measurement operation for forming an OCT image may be referred to as OCT measurement, the scan for performing OCT measurement may be referred to as OCT scan, and the data obtained by the OCT scan may be referred to as scan data.

Hereinafter, a case where the ophthalmic apparatus according to the embodiment includes an ophthalmic information processing apparatus will be described. The ophthalmic apparatus acquires a tomographic image of the eye to be inspected by performing OCT on the eye to be inspected. However, the ophthalmic information treatment apparatus according to the embodiment may be configured to acquire scan data (OCT data), a tomographic image, a shape profile described later, and the like from an external ophthalmic apparatus.

The ophthalmic apparatus according to some embodiments includes an OCT apparatus and is configured to align the eye under test with an optical system for performing OCT. Ophthalmic devices according to some embodiments further include objective refraction measuring devices. Ophthalmic devices according to some embodiments include devices (communication interfaces, input / output interfaces, etc.) that receive data from external devices and recording media.

That is, the ophthalmic apparatus according to the embodiment may be, for example, any of the following: (A) An inspection apparatus including an objective refraction measuring apparatus (refraction measuring unit) and an OCT apparatus (OCT unit): (B). An inspection device that does not include an objective refraction measuring device (refraction measuring unit) and includes an OCT device (OCT unit); (C) Neither an objective refraction measuring device (refraction measuring unit) nor an OCT device (OCT unit) is included. Information processing device.

In the following, the left-right direction (horizontal direction) orthogonal to the optical axis (measurement optical axis, inspection optical axis) of the device optical system of the ophthalmic apparatus is defined as the x direction, and the vertical direction (vertical direction) orthogonal to the optical axis is defined as the y direction. The direction of the optical axis (depth direction, front-back direction) is the z direction.

<Composition>
1 to 5 show a configuration example of the ophthalmic apparatus according to the embodiment. FIG. 1 is a functional block diagram showing a configuration example of the ophthalmic apparatus 1 according to the embodiment. FIG. 2 is a functional block diagram showing a configuration example of the data processing unit 70 of FIG. FIG. 3 is a functional block diagram showing a configuration example of the alignment processing unit 71 of FIG. FIG. 4 is a functional block diagram showing a configuration example of the specific unit 722 of FIG. FIG. 5 is a functional block diagram showing a configuration example of the calculation unit 73 of FIG.

The ophthalmic apparatus 1 is an inspection apparatus including an objective refraction measuring apparatus (refraction measuring unit) and an OCT apparatus (OCT unit). The ophthalmic apparatus 1 includes a measuring unit 10, a control processing unit 50, a moving mechanism 90, and an imaging unit 100. The measuring unit 10 includes a refraction measuring unit 20, an OCT unit 30, an alignment light projection unit 40, and beam splitters BS1 and BS2. The control processing unit 50 includes an image forming unit 60, a data processing unit 70, and a control unit 80.

(Refraction measuring unit 20)
The refraction measuring unit 20 objectively measures the refraction power of the eye E to be inspected under the control of the control unit 80. The refraction measuring unit 20 includes an optical system provided with one or more optical members for performing objective refraction measurement. The refraction measuring unit 20 has, for example, the same configuration as a known refractometer. Although not shown, a typical refractometer includes a projection system and a light receiving system as disclosed in JP-A-2016-07774.

The projection system of the refraction measuring unit 20 projects the light emitted from the light source onto the fundus Ef of the eye E to be inspected. The projection system projects light from a light source onto the fundus Ef through a collimating lens, a focusing lens, a relay lens, a pupil lens, a perforated prism, an eccentric prism, an objective lens, or the like.

The light receiving system of the refraction measuring unit 20 receives the reflected light from the fundus Ef into an objective lens, an eccentric prism, a perforated prism, another pupil lens, another relay lens, another focusing lens, a conical prism, an imaging lens, and the like. It is projected onto the image pickup element through. As a result, the ring pattern image formed on the image pickup surface of the image pickup device is detected.

In some embodiments, the refraction measuring unit 20 is configured to project ring-shaped light onto the fundus Ef and detect a ring pattern image formed by the reflected light from the fundus Ef. In some embodiments, the refraction measuring unit 20 projects a bright spot onto the fundus Ef, converts the reflected light from the fundus Ef into a ring-shaped light, and forms a ring pattern formed by the converted ring-shaped light. It is configured to detect an image.

(OCT section 30)
The OCT unit 30 receives control from the control unit 80, applies an OCT scan to the eye E to be inspected, and acquires OCT data (scan data). The OCT data may be interference signal data, reflection intensity profile data obtained by applying a Fourier transform to the interference signal data, or image data obtained by imaging the reflection intensity profile data.

The OCT method that can be performed by the OCT unit 30 is typically a Fourier domain OCT, and may be either a spectral domain OCT or a swept source OCT. The swept source OCT divides the light from the variable wavelength light source into the measurement light and the reference light, and superimposes the return light of the measurement light projected on the eye to be examined with the reference light to generate interference light, and generates interference light. This is a method of forming reflection intensity profile data by performing Fourier transform or the like on the detection data (interference signal data) detected by an optical detector and collected according to the sweeping of the wavelength and the scanning of the measurement light. On the other hand, the spectral domain OCT divides the light from the low coherence light source (broadband light source) into the measurement light and the reference light, and superimposes the return light of the measurement light projected on the eye to be examined with the reference light to generate interference light. Then, the spectral distribution of the interference light is detected by a spectroscope, and the detection data (interference signal data) by the spectroscope is subjected to Fourier transform or the like to form reflection intensity profile data. That is, the swept source OCT is an OCT method for acquiring the spectral distribution by time division, and the spectral domain OCT is an OCT method for acquiring the spectral distribution by spatial division.

The OCT unit 30 includes an optical system provided with one or more optical members for performing OCT measurement. The OCT unit 30 has, for example, the same configuration as a known OCT device. Although not shown, a typical OCT apparatus includes a light source, an interference optical system, a scanning system, and a detection system, as disclosed in Japanese Patent Application Laid-Open No. 2016-07774.

The light output from the light source is divided into measurement light and reference light by the interference optical system. The reference light is guided to the reference arm. The measurement light is projected onto the eye E (for example, fundus Ef) to be inspected through the measurement arm. The measuring arm is provided with a scanning system. The scanning system includes, for example, an optical scanner, and can deflect the measurement light one-dimensionally or two-dimensionally. Optical scanners include one or more galvano scanners. The scan system deflects the measurement light according to a predetermined scan mode.

The control unit 80, which will be described later, can control the scan system according to the scan mode. Scan modes include line scan, raster scan (three-dimensional scan), circle scan, concentric scan, radial scan, cross scan, multi-cross scan, spiral scan and the like. A line scan is a scan pattern that follows a linear trajectory. A raster scan is a scan pattern consisting of a plurality of line scans arranged parallel to each other. The circle scan is a scan pattern that follows a circular locus. A concentric scan is a scan pattern consisting of a plurality of circle scans arranged concentrically. A radial scan is a scan pattern consisting of a plurality of line scans arranged in a radial pattern. A cross scan is a scan pattern consisting of two line scans arranged orthogonally to each other. A multi-cross scan is a scan pattern consisting of two line scan groups orthogonal to each other (for example, each group contains five lines parallel to each other). A spiral scan is a scan pattern that extends spirally from the center.

The measurement light projected on the fundus Ef is reflected and scattered at various depth positions (layer boundaries, etc.) of the fundus Ef. The return light of the measurement light from the eye E to be inspected is combined with the reference light by the interference optical system. The return light of the measurement light and the reference light generate interference light according to the principle of superposition. This interference light is detected by the detection system. The detection system typically includes a spectroscope in the spectral domain OCT and a balanced photodiode and a data acquisition system (DAQ) in the swept source OCT.

(Alignment light projection unit 40)
The alignment light projection unit 40 projects the alignment light for aligning the eye to be inspected E with the measurement unit 10 (OCT unit, device optical system) to the eye to be inspected E. The alignment light projection unit 40 includes an alignment light source and a collimator lens. The optical path of the alignment light projection unit 40 is coupled to the optical path of the refraction measurement unit 20 by the beam splitter BS2. The light output from the alignment light source is reflected by the beam splitter BS2 via the collimator lens and projected onto the eye E to be inspected through the optical path of the refraction measuring unit 20.

In some embodiments, as disclosed in Japanese Patent Application Laid-Open No. 2016-077744, the light reflected by the cornea Ec (anterior segment) of the eye E to be inspected passes through the optical path of the refraction measuring unit 20 to the refraction measuring unit 20. It is guided to the light receiving system of.

An image (bright spot image) based on the reflected light from the cornea Ec of the eye E to be inspected is included in the anterior segment image acquired by the photographing unit 100. For example, the control processing unit 50 displays the front eye portion image including the bright spot image and the alignment mark on the display screen of the display unit (not shown). When manually performing XY alignment (alignment in the vertical and horizontal directions), the user can perform an operation of moving the optical system so as to guide a bright spot image within the alignment mark. When manually performing Z alignment (alignment in the front-rear direction), the user can perform an operation of moving the optical system while referring to the image of the anterior segment displayed on the display screen of the display unit. When performing automatic alignment, the control unit 80 controls the movement mechanism 90 so that the displacement between the alignment mark and the position of the bright spot image is canceled, so that the measurement unit 10 (optical system) with respect to the eye E to be inspected. ) Is moved relative to each other. Further, the control unit 80 controls the movement mechanism 90 so as to satisfy a predetermined alignment completion condition based on the position of a predetermined portion (for example, the center position of the pupil) of the eye E to be inspected and the position of the bright spot image. It is possible to move the measuring unit 10 (optical system) relative to the eye E to be inspected.

(Beam splitter BS1)
The beam splitter BS1 coaxially couples the optical path of the optical system (interference optical system, etc.) of the OCT unit 30 with the optical path of the optical system (projection system and light receiving system) of the refraction measuring unit 20. For example, a dichroic mirror is used as the beam splitter BS1.

(Beam splitter BS2)
The beam splitter BS2 coaxially couples the optical path of the optical system of the alignment light projection unit 40 with the optical path of the optical system (projection system and light receiving system) of the refraction measurement unit 20. For example, a half mirror is used as the beam splitter BS2.

In some embodiments, the ophthalmic apparatus 1 has a function (fixation projection system) of presenting a fixation target for guiding the line of sight of the subject E to the subject E under the control of the control unit 80. .. The fixation target may be an internal fixation target presented to the eye E to be inspected, or an external fixation target presented to the companion eye. In some embodiments, the optical path of the fixation projection system is coaxial with the optical path of the interference optical system of the OCT unit 30 due to an optical path coupling member (for example, a beam splitter) arranged between the OCT unit 30 and the beam splitter BS1. It is configured to be combined with.

Under the control of the control unit 80, the projection position of the fixation target on the fundus Ef by the fixation projection system can be changed. In some embodiments, the fixation target is projected onto the measurement optical axis of the coaxially coupled optical system of the refraction measuring unit 20 and the optical system of the OCT unit 30. In some embodiments, the fixation target is projected off the measurement optical axis at the fundus Ef.

(Photographing unit 100)
The imaging unit 100 includes one or more anterior segment cameras for photographing the anterior segment of the eye E to be inspected. The photographing unit 100 acquires an anterior segment image which is a front image of the eye E to be inspected. In some embodiments, at least one anterior segment illumination light source (such as an infrared light source) is provided in the vicinity of one or more anterior segment cameras. For example, for each anterior segment camera, an anterior segment illumination light source is provided in each of the upper vicinity and the lower vicinity thereof.

The ophthalmic apparatus 1 can align the measuring unit 10 (optical system) with respect to the eye E to be inspected by using the front image acquired by the photographing unit 100. In some embodiments, the ophthalmologic apparatus 1 identifies the three-dimensional position of the eye E to be inspected by analyzing the frontal image obtained by photographing the anterior segment of the eye to be inspected E, and the identified three-dimensional shape. Positioning is performed by relatively moving the measuring unit 10 based on the position. In some embodiments, the ophthalmic apparatus 1 aligns the feature position of the eye E to be inspected and the position of the image formed by the alignment light projected by the alignment light projection unit 40 so as to cancel the displacement. ..

As described above, the photographing unit 100 includes one or more front eye cameras. When the photographing unit 100 includes a single anterior segment camera, the ophthalmologic apparatus 1 analyzes the acquired front image and analyzes a plane (horizontal direction (X direction) and a vertical direction perpendicular to the optical axis of the measuring unit 10). The two-dimensional position of the eye to be inspected E in the plane defined by (Y direction) is specified. In this case, the ophthalmic apparatus 1 is provided with an alignment optical system for specifying the position of the eye E to be inspected in the direction of the optical axis of the measuring unit 10. Examples of such an alignment optical system include an optical optical system disclosed in Japanese Patent Application Laid-Open No. 2016-0777474. The ophthalmic apparatus 1 uses such an alignment optical system to specify the three-dimensional position of the eye E to be inspected from the position of the eye E to be inspected in the direction of the (measurement) optical axis of the measuring unit 10 and the above two-dimensional position. It is possible to do.

When the photographing unit 100 includes two or more anterior segment cameras, the two or more anterior segment cameras photograph the anterior segment of the eye E to be inspected from different directions. Two or more anterior segment cameras can image the anterior segment substantially simultaneously from two or more different directions. “Substantially at the same time” means that, for example, in imaging with two or more anterior segment cameras, a shift in imaging timing to the extent that eye movements can be ignored is allowed. Thereby, an image when the eye E to be inspected is in substantially the same position (orientation) can be acquired by two or more anterior eye cameras. As disclosed in, for example, Japanese Patent Application Laid-Open No. 2013-248376, the ophthalmic apparatus 1 analyzes the acquired front image to identify the feature position of the eye E to be inspected, and positions two or more anterior eye cameras. The three-dimensional position of the eye E to be inspected is specified from the characteristic position of the eye E to be inspected.

Shooting with two or more front eye cameras may be moving image shooting or still image shooting. In the case of moving image shooting, it is possible to realize substantially simultaneous anterior segment shooting as described above by controlling the shooting start timing to be adjusted, and controlling the frame rate and the shooting timing of each frame. .. On the other hand, in the case of still image shooting, this can be realized by controlling the shooting timing to be adjusted.

In the following, it is assumed that the photographing unit 100 includes two front eye cameras. Each of the two anterior segment cameras is provided at a position deviated from the measurement optical axis (optical axis of the OCT unit 30), for example, as disclosed in Japanese Patent Application Laid-Open No. 2013-248376. In some embodiments, one of the two front eye cameras is an image sensor in the light receiving system of the refraction measuring unit 20.

(Control processing unit 50)
The control processing unit 50 executes various calculations and various controls for operating the ophthalmic apparatus 1. The control processing unit 50 includes one or more processors and one or more storage devices. Examples of the storage device include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), and a solid state drive (SSD). Various computer programs are stored in the storage device, and the calculation and control according to this example are realized by operating the processor based on the various computer programs.

(Image forming unit 60)
The image forming unit 60 forms an image (tomographic image, etc.) of the eye E to be examined based on the scan data obtained by executing the OCT on the eye E to be examined. The image forming unit 60 constructs OCT data (typically image data) based on the detection data by the detection system of the OCT unit 30. The image forming unit 60 applies filtering, fast Fourier transform (FFT), and the like to the detection data in the same manner as the conventional OCT data processing, so that the reflection in each A line (path of measurement light in the eye E to be inspected) is reflected. Build intensity profile data. Further, the image forming unit 60 constructs the image data (A scan data) of each A line by applying the imaging process (image representation) to the reflection intensity profile data. In some embodiments, the function of the image forming unit 60 is realized by a processor.

In some embodiments, at least part of the function of the image forming unit 60 is provided in the OCT unit 30.

(Data processing unit 70)
The data processing unit 70 executes various data processing. The data processing unit 70 can construct B scan data by arranging a plurality of A scan data according to the scan mode by the scan system. In some embodiments, the data processing unit 70 performs superposition processing of two or more B scan data. The data processing unit 70 can construct stack data by arranging a plurality of B scan data according to the scan mode by the scan system. The data processing unit 70 can construct volume data (voxel data) from the stack data. The data processing unit 70 can render stack data or volume data. Rendering techniques include volume rendering, multi-section reconstruction (MPR), surface rendering, and projection.

The data processing unit 70 can execute a process for aligning the measurement unit 10 with respect to the eye E to be inspected. As processing for performing alignment, analysis processing of the front image of the eye E to be inspected obtained by using the photographing unit 100, calculation processing of the position of the eye E to be inspected, calculation processing of displacement of the measurement unit 10 with respect to the eye E to be inspected, etc. There is.

In addition, the data processing unit 70 acquires shape data (shape profile) representing the shape of the fundus Ef of the eye to be inspected E from the tomographic image of the eye to be inspected E obtained by executing OCT measurement after the alignment. From the shape data, it is possible to generate shape data representing the shape of the fundus Ef in a range different from the OCT measurement range. For example, the shape data is OCT shape data obtained by performing a segmentation process on a tomographic image as an OCT image. As a result, shape data representing the shape of the fundus Ef is acquired in a range wider than the OCT measurement range in which the tomographic image was acquired.

Further, the data processing unit 70 uses the specified shape of the fundus Ef (shape data representing the shape of the fundus Ef in a range wider than the OCT measurement range) to refract the peripheral region of the region including the fovea centralis of the eye E to be inspected. It is possible to calculate the frequency.

As shown in FIG. 2, such a data processing unit 70 includes an alignment processing unit 71, an analysis unit 72, and a calculation unit 73.

(Alignment processing unit 71)
As described above, the alignment processing unit 71 executes a process for aligning the measurement unit 10 with respect to the eye E to be inspected. In some embodiments, the alignment processing unit 71 corrects the distortion of the captured image obtained by the anterior segment camera, and executes the process for performing the above alignment using the distorted captured image. To do. In this case, the alignment processing unit 71 corrects the distortion of the captured image based on the aberration information stored in advance in the storage unit provided in the control processing unit 50 or the data processing unit 70. This process is performed, for example, by a known image processing technique based on a correction factor for correcting distortion.

As shown in FIG. 3, the alignment processing unit 71 includes a Purkinje image identification unit 71A, a pupil center identification unit 71B, and a movement target position determination unit 71C.

(Purkinje image identification part 71A)
The Purkinje image is formed by projecting the alignment light onto the anterior segment of the eye E to be examined by the alignment light projection unit 40. The Pulkinje image is formed at a position displaced from the apex of the cornea in the optical axis direction (z direction) of the measuring unit 10 by a distance of half the radius of curvature of the cornea.

The anterior segment to which the alignment light is projected is photographed substantially simultaneously by the two anterior segment cameras. The Purkinje image specifying unit 71A identifies a Purkinje image (an image region corresponding to a Purkinje image) by analyzing each of the two captured images acquired substantially at the same time by the two front eye cameras. This specific process includes, for example, a threshold value process related to a pixel value for searching for a bright spot (high-luminance pixel) corresponding to a Purkinje image, as in the conventional case. Thereby, the image area in the captured image corresponding to the Purkinje image is specified.

The Purkinje image identification unit 71A can determine the position of a representative point in the image region corresponding to the Purkinje image. The representative point may be, for example, the center point or the center of gravity point of the image region. In this case, the Purkinje image specifying unit 71A can obtain, for example, an approximate circle or an approximate ellipse at the periphery of the image region, and can obtain the center or the center of gravity of the approximate circle or the approximate ellipse.

Each of the two captured images (anterior segment image) is an image obtained by photographing the anterior segment from an oblique direction. A pupil region and a Purkinje image are depicted in each captured image. The Purkinje image specifying unit 71A identifies the Purkinje image in the two captured images.

Here, the two captured images are images acquired by photographing from a direction different from the optical axis of the measuring unit 10 (objective lens). When the XY alignment is substantially aligned, the Purkinje images in the two captured images are formed on the optical axis of the measuring unit 10.

Since the viewing angles (angles of the measuring unit 10 with respect to the optical axis) of the two anterior eye cameras are known and the imaging magnification is also known, the ophthalmic apparatus 1 (based on the positions of the Pulkinje images in the two captured images) The relative position (three-dimensional position in the real space) of the Pulkinje image formed in the anterior segment of the eye with respect to the photographing unit 100) can be obtained.

Further, based on the relative position (amount of deviation) between the characteristic position of the eye E to be inspected and the Pulkiner image in each of the two captured images, the position between the characteristic position of the eye E to be inspected and the Pulkiner image formed in the anterior segment of the eye The relative position can be obtained.

The Purkinje image specifying unit 71A specifies the position of the Purkinje image specified as described above. The position of the Purkinje image may include at least a position in the x direction (x coordinate value) and a position in the y direction (y coordinate value), and may further include a position in the z direction (z coordinate value).

(Pupil center specific part 71B)
The pupil center specific portion 71B analyzes each captured image (or an image corrected for distortion) obtained by the anterior segment camera, and thereby, in the captured image corresponding to a predetermined feature position of the anterior segment. Identify the location. In this embodiment, the pupil center of the eye E to be inspected is identified. The center of gravity of the pupil may be obtained as the center of the pupil. It can also be configured to specify a feature position other than the center of the pupil (center of gravity of the pupil).

The pupil center specifying portion 71B identifies an image region (pupil region) corresponding to the pupil of the eye E to be inspected based on the distribution of pixel values (luminance values, etc.) of the captured image. Since the pupil is generally expressed with a lower brightness than other parts, the pupil region can be specified by searching the low-brightness image region. At this time, the pupil region may be specified in consideration of the shape of the pupil. That is, it can be configured to specify the pupil region by searching for a substantially circular and low-luminance image region.

Next, the pupil center specifying portion 71B specifies the center position of the specified pupil region. Since the pupil is substantially circular as described above, the contour of the pupil region can be specified, the center position of the approximate ellipse of this contour can be specified, and this can be used as the center of the pupil. Further, the center of gravity of the pupil region may be obtained, and the position of the center of gravity may be set as the center of the pupil.

Even when other feature positions are applied, it is possible to specify the feature positions based on the distribution of pixel values of the captured image in the same manner as described above.

The pupil center identification portion 71B is a three-dimensional position of the pupil center of the eye E to be inspected based on the positions of the two anterior eye cameras (and the imaging magnification) and the positions of the pupil centers in the two identified captured images. To identify.

For example, the resolution of an image captured by two anterior segment cameras is expressed by the following equation.

Resolution in the xy direction (planar resolution): Δxy = H × Δp / f
Resolution in the z direction (depth resolution): Δz = H × H × Δp / (B × f)

Here, "B" represents the distance (baseline length) between the two anterior segment cameras, and "H" represents the distance between the baselines of the two anterior segment cameras and the center of the pupil of the eye E to be inspected (base line length). The shooting distance) is represented, “f” represents the distance (screen distance) between each front eye camera and its screen plane, and “Δp” represents the pixel resolution.

The pupil center identification portion 71B is formed by applying a known trigonometry to the positions of the two anterior segment cameras (known) and the positions corresponding to the pupil centers in the two captured images. Calculate the three-dimensional position of.

(Movement target position determination unit 71C)
The movement target position determining unit 71C moves the measuring unit 10 (device optical system) based on the position of the Purkinje image specified by the Purkinje image specifying unit 71A and the pupil center position specified by the pupil center specifying unit 71B. Determine the target position. For example, the movement target position determination unit 71C obtains the difference between the specified Purkinje image position and the specified pupil center position, and determines the movement target position so that the obtained difference satisfies the predetermined alignment completion condition. To do.

The control unit 80, which will be described later, can control the movement mechanism 90 based on the movement target position determined by the movement target position determination unit 71C.

(Analysis Unit 72)
As shown in FIG. 2, the analysis unit 72 includes a layer region identification unit 721 and a specific unit 722. The layer region identification unit 721 identifies a predetermined layer region (predetermined tissue) in the acquired tomographic image of the eye E to be inspected. The specific portion 722 specifies the shape of the fundus Ef based on the predetermined layer region specified by the layer region specific portion 721.

(Layer area identification unit 721)
The layer region identification unit 721 identifies a predetermined layer region of the fundus Ef by analyzing the tomographic image of the eye E to be inspected. The layer regions of the fundus Ef include the inner limiting membrane, nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, outer limiting membrane, photoreceptor layer, retinal pigment epithelial layer, There are choroids, sclera, and interfaces in each layer area.

The process of identifying a given layer region from a tomographic image typically includes a segmentation process. The segmentation process is a known process for identifying a partial region in a tomographic image. The layer region identification unit 721 performs a segmentation process based on, for example, the brightness value of each pixel in the tomographic image. That is, each layer region of the fundus Ef has a characteristic reflectance, and the image region corresponding to these layer regions also has a characteristic brightness value. The layer area specifying unit 721 can specify a target image area (layer area) by executing a segmentation process based on these characteristic luminance values.

The layer area specifying unit 721 outputs data representing the shape of the specified predetermined layer area as a shape profile of the layer area. In some embodiments, the shape profile is one-dimensional, two-dimensional, or three-dimensional shape data representing the shape of the fundus Ef in at least one of the x, y, and z directions.

For example, the layer region identification unit 721 can specify the retinal pigment epithelial layer (or OS-RPE interface).

(Specific part 722)
The identification unit 722 specifies the shape of the fundus Ef from the shape data (shape profile) obtained by the layer region identification unit 721. Specifically, the specific unit 722 refers to the above-mentioned OCT measurement range from the shape data of the predetermined layer region in the predetermined OCT measurement range (xy direction) obtained from the tomographic image acquired by executing the OCT measurement. The shape data representing the shape of the layer region is specified in a range (xy direction) different from the above. In some embodiments, the identification unit 722 is one-dimensional (two-dimensional or three-dimensional) in a measurement range wider than the OCT measurement range from a shape profile representing the shape of the layer region in one dimension (two-dimensional or three-dimensional) in the OCT measurement range. Generate a new shape profile that represents the shape of the layered region (three-dimensional).

As shown in FIG. 4, such a specific unit 722 includes a model construction unit 722A and a model expansion unit 722B.

(Model Construction Department 722A)
The model construction unit 722A constructs a shape profile model representing the shape of the layer region in the OCT measurement range specified by the layer region identification unit 721. The model is a model in which the specified layer region can be extended to a range different from the OCT measurement range. As such a model, a mathematical model that mathematically expresses the shape profile, a model that conceptualizes or abstracts the shape profile and expresses it as a principal component corresponding to the shape, and a conceptual or abstract shape profile. There is one shape model selected from a plurality of known shape models. Mathematical models include approximate expressions (for example, polynomials) in which the position in the direction intersecting the measurement optical axis is a variable. For the method of acquiring the main component corresponding to the shape, for example, "Quantitative Evaluation of Changes in Eyeball Shape in Polypropylene and Myopic Changes Based On Elliptic Fiber. No. 12, pp. 8585-8591) and the like. The conceptualization or abstraction of the shape profile includes a thinning process of the shape profile data.

In some embodiments, the model building unit 722A builds an estimation model that estimates the shape in a range different from the OCT measurement range from the shape profile described above. In general, it can be said that there is a statistically significant correlation between the shape of the fundus Ef, the refractive index of the eye E to be examined, and the intraocular parameter representing the structure of the eye E to be examined in the eye. Therefore, a shape profile representing the shape of a predetermined layer region within the OCT measurement range in the fundus Ef corresponding to the shape of the fundus Ef, the refractive index of the eye E to be inspected, and the intraocular parameters of the eye E to be inspected (for example, the axial length). ) Is used as teacher data, and a machine learning using a known machine learning algorithm such as a neural network is used to construct an estimation model that can output highly accurate shape data representing a shape in a range different from the OCT measurement range. It is possible. In some embodiments, the shape profile, the refractive power of the eye E to be examined, the measured values of the intraocular parameters of the eye E to be examined, and the subject's information (eg, age, gender, history, etc.) are taught. An estimation model is constructed as data.

By using any of the above models, as will be described later, the shape data in a predetermined range is expanded (predicted and estimated) as shape data in a range different from the range, and the shape in a range different from the range is highly accurate. It becomes possible to identify.

In the following, a case where the model building unit 722A mainly builds a mathematical model of a shape profile representing the shape of the layer region in the OCT measurement range will be described.

For example, the model construction unit 722A uses a polynomial (approximate curve) as a variable for the component of the relative position of the measurement optical axis of the OCT unit 30 with respect to the eye E to be inspected, based on the alignment reference position of the optical system with respect to the eye E to be inspected. Fit. Assuming that the above variable is d and the coefficients of each degree of the polynomial are c0, c1, ..., The polynomial f (d) corresponding to the shape profile is expressed by the following equation.

f (d) = c0 + c1 × d + c2 × d ² + c3 × d ³ + c4 × d ⁴ + ...

The coefficients c0, c1, ... Are determined so that the error between the shape profile and the polynomial is minimized. In the above equation, the component representing the slope corresponds to the primary component of d (that is, c1 × d). The component representing the curvature corresponds to the secondary component of d (c2 × d ² ). Components representing the distortion is equivalent to the tertiary component of ^d (c3 × d ^3).

In some embodiments, the model building unit 722A models the shape profile obtained by the layer region specifying unit 721 using an arbitrary approximation curve such as a spline curve.

In some embodiments, the model building unit 722A builds a model of the shape profile using, for example, an elliptical fitting process (including a circular fitting process). In this case, the model construction unit 722A acquires the correction shape profile (correction shape data) by performing the actual shape correction on the shape profile obtained by the layer region identification unit 721, and the acquired correction shape profile is obtained. The shape profile model is constructed by performing the ellipse fitting process. Here, the actual shape correction means the correction from the position of the OCT coordinate system to the position of the real space coordinate system to the real space at the time of OCT measurement. In the real space coordinate system, it is a coordinate system in which the optical distortion in the OCT measurement is removed. As an elliptical fitting process, for example, "Posterior Eye Shape Measurement With Retinal OCT Combined to MRI" (Anthony N. Kuo et al., IOVS, Special Issue, p. 19-. There are other methods.

In this case, the model building unit 722A performs a known circle fitting process on the corrected shape profile so that at least a part of the circumference is one or more circles (or the circumference thereof) along the shape of the predetermined layer region. Part of) is identified. For example, the model construction unit 722A performs a known circle fitting process using the least squares method and partial differentiation with the center position and radius of the circle as unknowns for each predetermined range of the correction shape profile to obtain an approximate circle in the range. Identify. The approximate circle is specified by the center position and the radius. By repeating the above circle fitting process, the model construction unit 722A can specify two or more approximate circles within a desired range of the correction shape profile. The model building unit 722A builds a model of the above (corrected) shape profile using the center positions and radii of two or more specified approximate circles.

In some embodiments, the model building unit 722A uses an ellipse or aspherical surface obtained by performing an elliptical fitting process or an aspherical surface fitting process on the corrected shape profile obtained by the layer region specifying unit 721. Build a model. For example, an aspherical equation using a conic constant is used for the aspherical fitting process.

When constructing a model of a shape profile using a plurality of known shape models, the model building unit 722A identifies a portion of the shape profile within an allowable error range from the shape model, and identifies the selected shape model. Build a model of the shape profile using the information and the parameters that represent the identified part.

(Model expansion unit 722B)
The model expansion unit 722B expands the model of the shape profile constructed by the model construction unit 722A to specify a shape in another new measurement range different from the measurement range from the shape profile of a predetermined measurement range. The model extension unit 722B can generate a shape profile representing the shape in the specified new measurement range. That is, the model expansion unit 722B outputs a shape profile in a range different from the above-mentioned predetermined measurement range (for example, a shape profile in a range wider than the predetermined measurement range).

The model expansion unit 722B extends the model by applying the model of the shape profile constructed by the model construction unit 722A to a range outside the OCT measurement range, so that the fundus Ef or the like in a range wider than the OCT measurement range can be obtained. It is possible to specify the shape. In some embodiments, the model extension unit 722B uses a model of the shape profile constructed by the model construction unit 722A and extrapolates the shape profile to cover a wider range than the OCT measurement range. Identify the shape of the fundus Ef and the like.

For example, when the shape profile is modeled by using the equation obtained by polynomial approximation by the model construction unit 722A, the model extension unit 722B uses the obtained equation to form the shape profile in a range different from the OCT measurement range. (Extension processing). Specifically, the model extension unit 722B uses the above polynomial f (d) constructed by the model construction unit 722A, and uses the shape profile represented by f (d) corresponding to the variable d in the new measurement range. To generate. That is, by extending the approximate curve represented by f (d) to the outside of the OCT measurement range, a shape profile in a range wider than the OCT measurement range can be obtained.

For example, when the shape profile is modeled using the center positions and radii of two or more approximate circles obtained by circle fitting by the model construction unit 722A, the model extension unit 722B is the center of two or more approximate circles. The position and radius are used to determine the shape profile in a range different from the OCT measurement range. Specifically, the model expansion unit 722B is the center position of the approximate circle in the new measurement range according to the change between the center position and the radius of two or more approximate circles in the OCT measurement range constructed by the model construction unit 722A. And the radius are specified, and the shape profile represented by the center position and radius of the specified approximate circle is output.

For example, when the shape profile is modeled by the shape model obtained by conceptualizing or abstracting by the model construction unit 722A, the model expansion unit 722B uses the obtained shape model to obtain the shape profile outside the OCT measurement range. Ask. Specifically, the model expansion unit 722B applies the data of the shape model constructed by the model construction unit 722A to the outside of the OCT measurement range, and generates a shape profile outside the OCT measurement range.

6 and 7 show an operation explanatory diagram of the specific unit 722 according to the embodiment. FIG. 6 shows an operation explanatory diagram of the model construction unit 722A. FIG. 7 shows an operation explanatory diagram of the model expansion unit 722B. In FIGS. 6 and 7, the horizontal axis represents the above variable d (for example, the position in the x direction, the scan position), and the vertical axis represents the depth position (for example, the position in the z direction).

The layer region identification unit 721 acquires a shape profile showing a change in the shape of a predetermined layer region (for example, the retinal pigment epithelial layer) by performing a segmentation process on the acquired tomographic image (for example, FIG. 6). Shape profile PF1). The shape profile PF1 is, for example, shape data representing a change in the depth direction of a predetermined layer region in an OCT measurement range of ± 3.0 [mm] with respect to an alignment reference position. The model construction unit 722A acquires a polynomial as shown in the above polynomial f (d) by, for example, polynomial approximation of the shape profile PF1 shown in FIG.

The model expansion unit 722B expands the shape profile PF1 shown in FIG. 6 and outputs a shape profile PF2 representing a change in the depth direction of a predetermined layer region in a range wider than the OCT measurement range. Specifically, the model extension unit 722B applies the above polynomial f (d) to a range of ± 12.0 [mm] with respect to the alignment reference position to generate the shape profile PF2 as shown in FIG. To do.

In some embodiments, the model extension unit 722B (or specific unit 722) is a polynomial (or approximation represented by the polynomial) obtained in a predetermined range of a range outside the OCT measurement range (second measurement range). It is possible to obtain a new shape profile by performing distortion correction processing on the curve). In some embodiments, the model expansion unit 722B (or specific unit 722) performs distortion correction processing on the shape profile in a predetermined range of the OCT measurement range, and extends the shape profile after the distortion correction processing to perform OCT. It is possible to obtain a new shape profile in the range outside the measurement range. The distortion correction process is a process for correcting distortion that becomes large mainly in the peripheral portion due to aberration of the optical system or the like.

In this case, the model expansion unit 722B can perform distortion correction processing based on standard eye data (known model eye data). As a result, it is possible to specify the shape of the fundus or the like in a range wider than the OCT measurement range by extrapolation processing while correcting the amount of large distortion in the peripheral portion.

In the model construction unit 722A and the model expansion unit 722B, an appropriate shape profile (shape data) and correction shape profile are selected according to the model.

(Calculation unit 73)
The calculation unit 73 obtains the refractive power obtained by objectively measuring the eye E to be inspected, and the calculated refractive power and the shape of the fundus Ef specified by the specific unit 722 (expanded by the model expansion unit 722B). The refractive power of the peripheral region of the region including the fovea centralis of the eye E to be inspected is calculated based on the shape profile. In some embodiments, the calculation unit 73 is based on the power of refraction obtained and the parameters representing the optical properties of the eye to be inspected corresponding to the shape of the fundus Ef specified by the specific unit 722. The refractive power of the peripheral region of the region including the fovea is calculated. The calculation unit 73 constructs an eyeball model based on the parameters representing the optical characteristics of the eye to be inspected corresponding to the shape of the fundus Ef specified by the specific unit 722, and is based on the constructed eyeball model and the obtained refractive power. It is possible to calculate the refractive power of the above peripheral region.

As shown in FIG. 5, the calculation unit 73 includes a refractive power calculation unit 73A, an eyeball model construction unit 73B, and a peripheral refractive power calculation unit 73C.

(Refractive power calculation unit 73A)
The refraction power calculation unit 73A processes the output from the image sensor of the light receiving system of the refraction measurement unit 20 to calculate the refraction power.

In some embodiments, the refractive index calculation unit 73A performs a process of specifying an elliptical shape by approximating the ring pattern image acquired by the image sensor to an ellipse, and adjusting the focus on the specified elliptical shape and a focusing lens. The process of obtaining the refractive index (measurement data) based on the diopter of the minute is executed.

In some embodiments, the refractive index calculation unit 73A obtains the brightness distribution in the image in which the ring pattern image acquired by the imaging element is drawn, and obtains the position of the center of gravity of the ring pattern image from the obtained brightness distribution. It is specified as a process, a process of obtaining a brightness distribution along a plurality of scanning directions radially extending from the obtained position of the center of gravity, and a process of specifying a ring pattern image from the obtained brightness distributions along a plurality of scanning directions. The process of obtaining the approximate ellipse of the ring pattern image and the process of calculating the luminance by substituting the major axis and the minor axis of the obtained approximate ellipse into a known equation are executed.

In some embodiments, the refractive power calculation unit 73A obtains the deviation (positional deviation, deformation, etc.) from the reference pattern of the ring pattern image acquired by the image sensor, and obtains the refractive power from this deviation. Perform processing and.

In some embodiments, the spherical power S, the astigmatic power C, and the astigmatic axis angle A are calculated as the refractive powers. In some embodiments, the equivalent spherical power SE (= S + C / 2) is calculated as the refractive power.

(Eyeball model construction unit 73B)
The eyeball model building unit 73B builds an eyeball model. The eyeball model building unit 73B can build a new eyeball model by applying parameters acquired separately to an eyeball model such as a known model eye.

The eye model construction unit 73B can construct a new eye model by applying the intraocular distance of the eye E to be inspected obtained by OCT measurement or the like as an actual measurement parameter to an eye model such as a known model eye. It is possible. In this case, the data processing unit 70 can execute a calculation process for obtaining the size (layer thickness, volume, etc.) of the tissue and the distance between predetermined parts. For example, the data processing unit 70 identifies the peak position of the detection result (interference signal) of the interference light corresponding to a predetermined part in the eye by analyzing the scan data or the tomographic image, and the distance between the specified peak positions. The intraocular distance is calculated based on. In some embodiments, the data processor 70 is an intraocular distance (interlayer distance) based on the number of pixels present between the two layer regions obtained by the segmentation process and a predetermined pixel spacing correction value. )Ask. The measurement of the intraocular distance is performed along a predetermined direction. The measurement direction of the intraocular distance may be, for example, a direction determined by an OCT scan (for example, a traveling direction of the measurement light) or a direction determined based on scan data (for example, a direction orthogonal to a layer). Further, the distance data may be distance distribution data between two layer regions, or statistical values calculated from the distance distribution data (for example, mean, maximum value, minimum value, median value, mode, variance, standard). Deviation) or distance data between representative points of each layer region. The intraocular distance that can be calculated by the data processing unit 70 includes the axial length, the corneal thickness, the depth of the anterior chamber, the lens thickness, the vitreous cavity length, the retina film thickness, and the choroid film thickness. Further, the data processing unit 70 can calculate various parameters representing the optical characteristics of the eyeball by using the obtained intraocular distance.

In some embodiments, the identification unit 722 (or eye model construction unit 73B) is capable of identifying the shape of the fundus Ef using the constructed eye model. For example, the specific unit 722 specifies the shape (actual shape) of the fundus Ef by obtaining the difference in the depth position between the central region and the peripheral region of the fundus Ef.

(Peripheral refraction power calculation unit 73C)
Peripheral refractive power calculation unit 73C calculates the refractive power of the peripheral region outside the central region including the fovea centralis in the fundus Ef. At this time, the peripheral refractive power calculation unit 73C calculates the refractive power of the peripheral region based on the refractive power of the central region obtained by the refraction measuring unit 20 and the shape of the fundus Ef specified by the specific unit 722. .. Peripheral refractive power calculation unit 73C can calculate the refractive power of the peripheral region by using the parameters of the eyeball model constructed by the eyeball model construction unit 73B.

In some embodiments, the function of the data processing unit 70 is realized by one or more processors. In some embodiments, the functions of the alignment processing unit 71, the analysis unit 72, and the calculation unit 73 are realized by a single processor. In some embodiments, the functions of each part of the alignment processing unit 71 are realized by a single processor. In some embodiments, the function of the analyzer 72 is realized by a single processor. In some embodiments, the functions of each part of the calculation unit 73 are realized by a single processor. In some embodiments, at least a portion of the data processing unit 70 is provided in the refraction measuring unit 20 or the OCT unit 30.

(Control unit 80)
The control unit 80 controls each unit of the ophthalmic apparatus 1. The control unit 80 includes a storage unit (not shown) and can store various types of information. The information stored in the storage unit includes a program for controlling each unit of the ophthalmic apparatus 1, information on the subject, information on the eye to be inspected, measurement data obtained by the measurement unit 10, and processing results by the data processing unit 70. and so on. The function of the control unit 80 is realized by the processor.

The control unit 80 can control a display device (not shown). The display device functions as a part of the user interface and displays information under the control of the control unit 80. The display device may be, for example, a liquid crystal display (LCD) or an organic light emitting diode (OLED) display.

The control unit 80 can control the ophthalmologic device 1 according to a signal from an operation device (not shown). The operating device functions as part of the user interface. The operating device may include various hardware keys (joysticks, buttons, switches, etc.) provided in the ophthalmic apparatus 1. Further, the operation device may include various peripheral devices (keyboard, mouse, joystick, operation panel, etc.) connected to the ophthalmic device 1. The operating device may also include various software keys (buttons, icons, menus, etc.) displayed on the touch panel.

(Movement mechanism 90)
The moving mechanism 90 moves the head portion containing the optical systems (device optical systems) such as the refraction measuring unit 20, the OCT unit 30, the alignment light projection unit 40, the beam splitter BS1 and BS2 in the vertical and horizontal directions and the front-rear direction. It is a mechanism for. The moving mechanism 90 is controlled by the control unit 80 and can move the measuring unit 10 relative to the eye E to be inspected. For example, the moving mechanism 90 is provided with an actuator that generates a driving force for moving the head portion and a transmission mechanism that transmits the driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is composed of, for example, a combination of gears and a rack and pinion. The control unit 80 controls the moving mechanism 90 by sending a control signal to the actuator.

Control over the moving mechanism 90 is used in alignment. For example, the control unit 80 acquires the current position of the measurement unit 10 (device optical system). The control unit 80 receives the information representing the content of the movement control of the movement mechanism 90 and acquires the current position of the measurement unit 10. In this case, the control unit 80 controls the moving mechanism 90 at a predetermined timing (when the device is started, when the patient information is input, etc.) to move the measuring unit 10 to a predetermined initial position. After that, the control unit 80 records the control content each time the moving mechanism 90 is controlled. As a result, a history of control contents can be obtained. As the optical system position acquisition unit, the control unit 80 acquires the control contents up to the present with reference to this history, and obtains the current position of the measurement unit 10 based on the control contents.

In some embodiments, each time the control unit 80 controls the moving mechanism 90, the current position of the measuring unit 10 is sequentially obtained in response to the control content. In some embodiments, the ophthalmic apparatus 1 is provided with a position sensor that detects the position of the measuring unit 10, and the control unit 80 acquires the current position of the measuring unit 10 based on the detection result of the position sensor.

The control unit 80 can control the movement mechanism 90 based on the current position acquired as described above and the movement target position determined by the movement target position determination unit 71C. As a result, the measuring unit 10 can be moved to the moving target position. For example, the control unit 80 obtains the difference between the current position and the movement target position. This difference value is, for example, a vector value whose start point is the current position and whose end point is the movement target position. This vector value is, for example, a three-dimensional vector value represented by the xyz coordinate system.

In some embodiments, control over the moving mechanism 90 is used in tracking. Tracking is to move the device optical system according to the eye movement of the eye E to be inspected. When tracking is performed, alignment and focus adjustment are performed in advance. Tracking is a function of maintaining a suitable positional relationship in which alignment and focus are achieved by making the position of the optical system of the device follow the movement of the eyeball.

The control processing unit 50 or the data processing unit 70 is an example of the "ophthalmic information processing device" according to the embodiment. The OCT unit 30, the image forming unit 60, an external device (external ophthalmic device), or a device (communication interface, input / output interface, etc.) that receives data from a recording medium is an example of the “acquisition unit” according to the embodiment. .. The shape profile obtained by the layer region specifying unit 721 is an example of the "first shape data" according to the embodiment. The layer area identification unit 721 is an example of the “organization identification unit” according to the embodiment. The shape profile obtained by the model expansion unit 722B is an example of "second shape data" according to the embodiment. The specific unit 722 or the model extension unit 722B is an example of the "specific unit" according to the embodiment. The calculation unit 73 or the peripheral refractive power calculation unit 73C is an example of the “calculation unit” according to the embodiment.

<Operation example>
The operation of the ophthalmic apparatus 1 according to the embodiment will be described.

8 and 9 show an example of the operation of the ophthalmic apparatus 1. FIG. 8 shows a flow chart of an operation example of the ophthalmic apparatus 1. FIG. 9 shows a flow chart of an operation example of step S3 of FIG. The storage unit of the control unit 80 stores a computer program for realizing the processes shown in FIGS. 8 and 9. The control unit 80 executes the processes shown in FIGS. 8 and 9 by operating according to this computer program.

(S1: Alignment)
First, the control unit 80 executes alignment.

For example, the control unit 80 controls the alignment light projection unit 40 to project the alignment light onto the eye E to be inspected. At this time, the fixation light flux is projected onto the eye E to be examined by a fixation projection system (not shown) at a predetermined projection position (for example, a projection position on the measurement optical axis). The control unit 80 specifies, for example, the movement amount and movement direction of the measurement unit 10 from the displacement between the position of the pupil center and the position of the Purkinje image in the captured image acquired by the imaging unit 100, and the specified movement amount and movement. The movement mechanism 90 is controlled based on the direction, and the measurement unit 10 is aligned with the eye E to be inspected. The control unit 80 repeatedly executes this process until a predetermined alignment completion condition is satisfied.

(S2: Objective refraction measurement)
Next, the control unit 80 controls an fixation projection system (not shown) to project the fixation target on the measurement optical axis of the optical system of the refraction measurement unit 20 in the fundus Ef (central fixation). After that, the control unit 80 executes objective refraction measurement by controlling the refraction measurement unit 20 in a state where the fixation target is projected on the measurement optical axis of the optical system of the refraction measurement unit 20.

The refractive power calculation unit 73A calculates the refractive power of the central region including the fovea centralis of the eye E to be inspected by analyzing the ring pattern image formed by the reflected light of the light projected on the fundus Ef of the eye E to be inspected.

(S3: Specify the shape of the fundus)
Subsequently, the control unit 80 executes a process of specifying the shape of the fundus Ef of the eye E to be inspected. In this embodiment, the control unit 80 controls the OCT unit 30 in a state where the fixation target is projected on the measurement optical axis of the optical system of the refraction measurement unit 20 (OCT unit 30) to perform OCT measurement (OCT). Scan) is executed.

In step S3, shape data representing the shape of the fundus Ef is acquired as described above. The details of step S3 will be described later.

(S4: Calculate peripheral refractive power)
Subsequently, the control unit 80 causes the peripheral dioptric power calculation unit 73C to calculate the refractive power of the peripheral region outside the central region including the fovea obtained in step S2. Therefore, the control unit 80 causes the eyeball model building unit 73B to build the eyeball model.

Specifically, the eyeball model construction unit 73B acquires the Highweight data [pixel] of a predetermined layer region from the shape data obtained in step S3. The hight data corresponds to the distance in the depth direction from the predetermined reference position in the tomographic image. The eyeball model building unit 73B acquires the distance [mm] of the Highweight data by using the pixel spacing correction value [mm / pixel] defined by the optical system and which is unique to the device. Further, the eyeball model building unit 73B builds an eyeball model using the acquired Height data as fundus shape data.

FIG. 10 shows an operation explanatory view of the eyeball model construction unit 73B according to the embodiment. FIG. 10 schematically shows some of the parameters of the eyeball model.

The eyeball model construction unit 73B is an eyeball composed of a predetermined corneal radius of curvature (for example, 7.7 mm) and a predetermined axial length (for example, 24.2 mm) by using the parameters of an eyeball model such as a Gullstrand model eye. Build a model.

As shown in FIG. 10, the eye model construction unit 73B sets a device-specific pivot point Pv between the cornea Ec and the fundus Ef in the eye model. Typically, a position corresponding to the pupil position (for example, a position 3 mm posterior to the corneal Ec) located at a position optically conjugate with the optical scanner constituting the scanning system is set as the pivot point Pv. Ru. The equidistant (equal optical path length) position (ELS) with respect to the pivot point Pv corresponds to a flat position in the tomographic image obtained by OCT measurement.

In the eyeball model, since the axial length AL and the distance Lp from the anterior surface (posterior surface) of the cornea to the pivot point Pv are known, the distance (AL-Lp) from the pivot point Pv to the fundus Ef is known. When the radius of curvature of the fundus Ef is equal to the distance (AL-Lp), it corresponds to the flat position in the tomographic image as described above, so that the eyeball model construction unit 73B uses the distance [mm] of the obtained Height data. It is possible to specify the shape of the fundus Ef (for example, the radius of curvature).

Therefore, the eyeball model construction unit 73B obtains the difference in height (fundus shape difference data) Δh [mm] of the peripheral region with respect to the central region (fovea centralis). The difference Δh may be obtained for each A line in the tomographic image, or may be fitted by an arbitrary function such as a polynomial or an aspherical expression (polynomial including a conic constant).

Next, the peripheral refractive power calculation unit 73C defines the eyeball refractive power of the entire eye system in order to relate the fundus shape and the refractive power. In a typical eye model (Gullstrand model eye (precision model eye, accommodative dormant state)), the optical power of the whole eye system is 58.64 [diopter]. In terms of air equivalent length, the focal length of the whole eye system is "1000 / 58.64 = 17.05" [mm]. The unit [mm] information obtained using the pixel spacing correction value usually represents the distance in the living tissue, so the focal length of the whole eye system in the living tissue is calculated by multiplying the refractive index. It is calculated. Assuming that the equivalent refractive index of the whole eye system is n = 1.38, the focal length ft of the whole eye system in the living tissue is “1000 / 58.64 × 1.38 = 23.53” [mm].

The peripheral refractive power calculation unit 73C calculates the difference ΔD of the eyeball refractive power at the position of the difference Δh in the height of the peripheral region with respect to the central region (fovea centralis) according to the equation (1). The difference ΔD corresponds to the difference in the refractive power of the eyeball relative to the central region including the fovea centralis.

For example, when Δh = 0.1 [mm] (tissue), ΔD = 0.18 [diopter].

As shown in the equation (2), the peripheral refractive power calculation unit 73C obtains the refractive power SEp of the peripheral region by applying the difference ΔD of the equation (1) to the equivalent spherical power SE of the central region.

Peripheral refraction power calculation unit 73C may obtain the refraction power of the peripheral region in the tomographic image for each A line, or may be fitted by an arbitrary function.

In some embodiments, the peripheral power calculation unit 73C calculates the power of refraction at each of the plurality of parts of the peripheral region of the region including the fovea centralis of the eye to be inspected, and obtains the calculated statistical values of the plurality of powers of refraction. calculate. In some embodiments, the plurality of refractive powers is the refractive powers of a plurality of sites having a line-symmetrical or point-symmetrical relationship with respect to the region including the fovea in the peripheral region. In some embodiments, the statistic is the mean, maximum, minimum, median, or mode of the plurality of refractive powers.

This completes the operation of the ophthalmic apparatus 1 (end).

In step S3 of FIG. 8, as shown in FIG. 9, the process of specifying the shape of the fundus Ef of the eye E to be inspected is executed.

(S11: Start projection of alignment light)
When the process of step S3 is started, the control unit 80 controls the alignment light projection unit 40 to start the projection of the alignment light to the eye E to be inspected, as in step S1.

In step S11 as well, similarly to step S1, the fixation light flux is projected onto the eye E to be examined by a fixation projection system (not shown) at a predetermined projection position (for example, a projection position on the measurement optical axis).

(S12: Alignment)
The control unit 80 specifies the movement amount and movement direction of the measurement unit 10 from the displacement between the position of the pupil center and the position of the Purkinje image in the captured image acquired by the imaging unit 100, and sets the movement amount and movement direction to the specified movement amount and direction. Based on this, the moving mechanism 90 is controlled to align the measuring unit 10 with respect to the eye E to be inspected.

(S13: Alignment completed?)
The control unit 80 determines whether or not the predetermined alignment completion condition is satisfied. The alignment completion conditions are that the positions of the optical axis of the measuring unit 10 in the x and y directions coincide with the positions of the moving target position in the x and y directions, and that the distance in the z direction becomes a predetermined operating distance. including. In some embodiments, the predetermined working distance is the working distance of the measuring unit 10 (objective lens).

When it is determined that the predetermined alignment completion condition is not satisfied (S13: N), the operation of the ophthalmic apparatus 1 shifts to step S12. When it is determined that the predetermined alignment completion condition is satisfied (S13: Y), the operation of the ophthalmic apparatus 1 shifts to step S14.

(S14: OCT measurement)
When it is determined in step S13 that the predetermined alignment completion condition is satisfied (S13: Y), the control unit 80 controls the OCT unit 30 to perform an OCT scan on a predetermined site in the fundus Ef. By executing it, OCT measurement is executed. The predetermined site is the fovea centralis or its vicinity. The OCT scan includes a radial scan and the like.

(S15: Forming a tomographic image)
Subsequently, the control unit 80 causes the image forming unit 60 to form a tomographic image of the eye E to be inspected based on the scan data obtained in step S14.

(S16: Segmentation process)
Next, the control unit 80 causes the layer region identification unit 721 to specify a predetermined layer region (for example, the retinal pigment epithelial layer) by performing a segmentation process on the tomographic image formed in step S15. As a result, shape data (shape profile) of a predetermined layer region is acquired.

(S17: Model construction process)
Next, the control unit 80 controls the model construction unit 722A to construct a model of the shape data in the OCT measurement range obtained in step S16. The model construction unit 722A acquires a polynomial (for example, the above-mentioned polynomial f (d)) by, for example, polynomial approximation of the shape data.

(S18: model expansion processing)
The control unit 80 applies the polynomial acquired in step S17 to a range outside the OCT measurement range, and causes the model extension unit 722B to generate shape data in a new range. The model extension unit 722B uses the above polynomial f (d) to specify the shape of a predetermined range outside the OCT measurement range, and outputs it as a shape profile representing the shape of the specified predetermined layer region. .. In step S4 of FIG. 8, the profile output in step S18 is used as data representing the shape of a predetermined layer region (for example, the retinal pigment epithelial layer) corresponding to the shape of the fundus Ef.

This completes the process of step S3 in FIG. 8 (end).

<Modification example>
The configuration and operation of the ophthalmic apparatus according to the embodiment are not limited to those described above.

[First modification]
In step S4, the eyeball model construction unit 73B measures the measured data of the eye to be inspected E (for example, axial length, corneal shape, anterior chamber depth, crystalline lens curvature, and crystalline lens thickness) among the parameters of the eyeball model such as the Gullstrand model eye. A new eye model may be constructed by replacing at least one of the values). In some embodiments, the measured data is obtained from an external measuring device or electronic medical record system. In some embodiments, axial length, anterior chamber depth, lens curvature, and lens thickness are determined from scan data obtained by the OCT unit 30.

For example, the peripheral refractive index calculation unit 73C (or data processing unit 70) uses the constructed new eyeball model to perform ray tracing processing on a ray that is incident from the cornea Ec, passes through the pupil, and reaches the fundus Ef. (For example, pupil diameter = φ4). In the ray tracing process, the position of the object point is set to a position corresponding to a far point obtained from the refractive power (equivalent spherical power SE) in the central region acquired in step S2. The far point distance L from the corneal Ec to the position corresponding to the far point is "-1000 / SE" [mm].

First, the peripheral refractive power calculation unit 73C performs ray tracing processing on the central region. Since the measured data is applied to the eyeball model as described above, there is a possibility that the light beam does not converge at the fundus Ef even in the central region. In this case, the peripheral refractive power calculation unit 73C fine-tunes the parameters of the eyeball model so that the light rays converge in the central region (the surface of the fundus Ef is the best image plane).

Next, the peripheral refractive power calculation unit 73C performs light ray tracing processing on the peripheral region using the eyeball model whose parameters have been finely adjusted (that is, an incident angle is provided with respect to the measurement optical axis passing through the rotation point of the eye). Track the rays of light). Peripheral refraction power calculation unit 73C performs ray tracing processing while changing the distance to the object point to obtain the distance to the object point where the light beam converges at the fundus Ef in the peripheral region. The obtained distance to the object point corresponds to the distance point distance Lp in the peripheral region. Peripheral refractive power calculation unit 73C can obtain the refractive power SEp [diopter] of the peripheral region by using the equation (3).

Peripheral refraction power calculation unit 73C performs ray tracing processing while changing the incident angle in a predetermined incident angle range, and obtains the refractive power SEp of the peripheral region for each incident angle (angle of view). The refractive power of the peripheral region may be a discrete value for each incident angle, or may be fitted by an arbitrary function within the incident angle range.

In this modification, since the eyeball model is finely adjusted so that the light rays converge in the fundus Ef shape in the central region, the obtained refractive power of the peripheral region corresponds to the relative refractive power of the central region.

[Second modification]
In the above embodiment or a modification thereof, the model construction unit 722A constructs a model of the shape profile obtained by the layer region identification unit 721, and the model expansion unit 722B extends the constructed model to the OCT measurement range. Although the case of specifying a predetermined layer region in a range different from the above has been described, the configuration according to the embodiment is not limited to this.

The shape profile obtained by the layer region specifying portion 721 may be affected by an alignment error (misalignment). Therefore, in this modification, the model construction unit 722A constructs a model of a new shape profile obtained by statistically processing the shape profile obtained by the layer region identification unit 721.

The ophthalmic information processing apparatus according to this modified example acquires a plurality of tomographic images of the eye E to be inspected. A plurality of tomographic images can be obtained, for example, by repeatedly performing OCT on the eye E to be inspected using an external ophthalmic apparatus. The layer region identification unit 721 analyzes each of the acquired tomographic images to acquire a plurality of shape profiles of a predetermined tissue, and a new shape representing the true shape of the tissue from the acquired plurality of shape profiles. Identify the profile. In this case, the specific unit 722 (or model construction unit 722A) specifies a shape profile representing a true shape by performing statistical processing on a plurality of shape profiles. Statistical processing includes averaging processing, median calculation processing, mode calculation processing, maximum likelihood calculation processing, maximum value calculation processing, minimum value calculation processing, and the like. Statistical processing may include representative value selection processing.

In this modification, the model building unit 722A builds a model of the shape profile after statistical processing. Similar to the above embodiment, the model expansion unit 722B extends the constructed model to specify a predetermined layer region in a range different from the OCT measurement range.

According to this modification, the influence of the amount of misalignment (alignment error amount) of the optical system for performing OCT on the eye E to be inspected is reduced, and the shape of the tissue of the eye to be inspected is specified with high reproducibility and high accuracy. It becomes possible to do. Therefore, the shape of the tissue in a range different from the OCT measurement range can be specified with higher accuracy.

In some embodiments, the model building unit 722A performs the above statistical processing on a plurality of models constructed using the plurality of tomographic images to acquire a new model. The model expansion unit 722B performs the model expansion processing as described above on the model acquired by the statistical processing.

In some embodiments, the model expansion unit 722B statistically processes the shape profile outside the OCT measurement range obtained by the model expansion processing on the constructed model for a plurality of tomographic images, and the shape profile after the statistical processing. Is output.

[Third variant]
In the second modification of the above embodiment, the case where the influence of the misalignment amount is reduced by statistical processing has been described, but the configuration according to the embodiment is not limited to this.

The shape profile obtained by analyzing the tomographic image shows a high-sensitivity component with a large fluctuation and a small fluctuation with respect to a change (small change) in the position of the optical system for executing OCT with respect to the eye E to be inspected. Contains low-sensitivity components. In some embodiments, the identification unit 722 (or model construction unit 722A) identifies the low-sensitivity component from the shape profile obtained by analyzing the tomographic image and extracts the identified low-sensitivity component to form a tissue. Identify a shape profile that represents the true shape of. In some embodiments, the identification section 722 identifies a sensitive component from the shape profile obtained by analyzing the tomographic image and removes the sensitive component from the shape profile to represent the true shape of the tissue. Identify the profile.

Here, the high-sensitivity component means a component of the shape profile whose fluctuation is large with respect to a slight change in alignment error. The low-sensitivity component means a component of the shape profile whose fluctuation is small with respect to a slight change in alignment error.

In some embodiments, the shape profile is approximated by an equation represented by a high sensitivity component and a low sensitivity component. In some embodiments, the shape profile is approximated by an equation represented by a high-sensitivity component, a low-sensitivity component, and other components.

Further, when the shape profile is expressed with the relative position of the measurement optical axis of the OCT unit 30 with respect to the eye E to be examined as a variable with the alignment reference position as a reference, the asymmetric component of the shape profile is a high-sensitivity component. On the other hand, the symmetric component of the shape profile is a low sensitivity component. The high-sensitivity component includes an odd-order component of the variable of the above polynomial f (d). Examples of high-sensitivity components include a component representing inclination and a component representing distortion. The low-sensitivity component includes an even-order component of the variable of the above polynomial f (d). Examples of low-sensitivity components include components that represent curvature.

In the above polynomial f (d), the component representing the slope corresponds to the first-order component of d (that is, c1 × d). The component representing the curvature corresponds to the secondary component of d (c2 × d ² ). Components representing the distortion is equivalent to the tertiary component of ^d (c3 × d ^3).

In this modification, the model building unit 722A builds a model having a shape profile composed of the extracted low-sensitivity components or a shape profile from which the high-sensitivity components have been removed. Similar to the above embodiment, the model expansion unit 722B extends the constructed model to specify a predetermined layer region in a range different from the OCT measurement range.

According to this modification, the influence of the amount of misalignment (alignment error amount) of the optical system for performing OCT on the eye E to be inspected is reduced, and the shape of the tissue of the eye to be inspected is specified with high reproducibility and high accuracy. It becomes possible to do. Therefore, the shape of the tissue in a range different from the OCT measurement range can be specified with higher accuracy.

[effect]
The ophthalmic apparatus according to the embodiment and the control method thereof will be described.

The ophthalmic information processing apparatus (control processing unit 50, or data processing unit 70) according to some embodiments can be obtained from an acquisition unit (OCT unit 30, image forming unit 60, external device (external ophthalmic device), or recording medium. It includes a device (communication interface, input / output interface, etc.) for receiving data, an organization identification unit (layer area identification unit 721), and a specific unit (722, model expansion unit 722B). The acquisition unit acquires a tomographic image of the eye to be inspected formed based on the scan data obtained by performing OCT measurement on the eye to be inspected (E). The tissue identification unit acquires the first shape data (shape profile) representing the shape of the tissue of the eye to be inspected in the first measurement range (OCT measurement range) by performing a segmentation process on the tomographic image. Based on the first shape data, the specific unit obtains the second shape data representing the shape of the tissue of the eye to be inspected in the second measurement range different from the first measurement range.

According to such a configuration, the second measurement different from the first measurement range is obtained from the first shape data representing the shape of the tissue in the first measurement range obtained by performing the segmentation processing on the tomographic image of the eye to be inspected. Second shape data representing the shape of the tissue in the range is acquired. As a result, it becomes possible to accurately identify the shape of the tissue of the eye to be inspected not only in the first measurement range but also in a wider range.

In the ophthalmic information processing apparatus according to some embodiments, at least a part of the second measurement range overlaps with the first measurement range.

According to such a configuration, the second measurement range is wider than the first measurement range. Therefore, it is possible to identify the shape of the tissue of the eye to be inspected with high accuracy in a range wider than the first measurement range.

In the ophthalmic information processing apparatus according to some embodiments, the second measurement range includes the first measurement range.

According to such a configuration, the second measurement range is wider than the first measurement range. Therefore, it is possible to identify the shape of the tissue of the eye to be inspected with high accuracy in a range wider than the first measurement range.

In the ophthalmic information processing apparatus according to some embodiments, the specific unit obtains the second shape data in the second measurement range by executing the extrapolation process based on the first shape data.

According to such a configuration, the extrapolation process is executed based on the first shape data in the first measurement range, so that the second shape data in the second measurement range is obtained. The shape of the tissue of the eye to be inspected can be specified with high accuracy in a range wider than the first measurement range.

In the ophthalmic information processing apparatus according to some embodiments, the specific unit specifies an approximate curve of the first shape data, and obtains the second shape data using the specified approximate curve.

According to such a configuration, the shape of the tissue in the second measurement range is specified from the approximate curve of the first shape data in the first measurement range. Therefore, a simple process is performed in a range wider than the first measurement range. It becomes possible to identify the shape of the tissue of the eye to be inspected with high accuracy.

In the ophthalmic information processing apparatus according to some embodiments, the specific unit obtains the second shape data by performing distortion correction processing on the approximate curve in a predetermined range of the second measurement range.

According to such a configuration, since the distortion-corrected second shape data is obtained in a predetermined range of the second measurement range, the distortion of the shape of the tissue of the eye to be inspected in the periphery is corrected, and the tissue of the eye to be inspected is corrected. It becomes possible to specify the shape of the above with high accuracy.

In the ophthalmic information processing apparatus according to some embodiments, the specific unit acquires the correction shape data by performing the actual shape correction on the first shape data, and performs ellipse fitting processing on the acquired correction shape data. The second shape data is obtained based on the shape of the ellipse obtained by performing the above.

According to such a configuration, the shape of the ellipse obtained by performing the actual shape correction on the first shape data in the first measurement range and performing the ellipse fitting process on the shape data after the actual shape correction is performed. The shape of the tissue in the second measurement range is specified. As a result, it becomes possible to identify the shape of the tissue of the eye to be inspected with high accuracy in a range wider than the first measurement range by a simple process.

In the ophthalmic information processing apparatus according to some embodiments, the specific unit performs distortion correction processing based on standard data of the eye.

According to such a configuration, by performing distortion correction corresponding to the standard data of the eye, it becomes possible to identify the shape of the tissue of the eye to be inspected with high accuracy while reflecting the standard structure of the eye. ..

In the ophthalmic information processing apparatus according to some embodiments, the tissue comprises a predetermined layer area in the fundus.

With such a configuration, it is possible to specify the shape of the fundus of the eye to be inspected with high accuracy not only in the first measurement range but also in a wider range.

The ophthalmic information processing apparatus according to some embodiments has a subject corresponding to the refractive index obtained by objectively measuring the eye to be inspected and the shape of the tissue based on the second shape data acquired by the specific portion. A calculation unit (peripheral refractive index calculation unit 73C) for calculating the refractive index of the peripheral region of the region including the central fossa of the eye to be inspected is included based on the parameters representing the optical characteristics of the eye examination.

According to such a configuration, it is possible to acquire the refractive power of the peripheral region of the region including the fovea with high accuracy according to the shape of the fundus of the eye to be inspected.

The ophthalmic apparatus (1) according to some embodiments includes an optical system (an optical system included in the OCT unit 30) for performing OCT measurement on the eye to be inspected, and ophthalmic information processing according to any one of the above. Including the device.

According to such a configuration, it becomes possible to provide an ophthalmic apparatus capable of identifying the shape of the tissue of the eye to be inspected with high accuracy not only in the first measurement range but also in a wider range.

The ophthalmologic information processing methods according to some embodiments include an acquisition step of acquiring a tomographic image of the eye to be inspected formed based on scan data obtained by performing OCT measurement on the eye to be inspected (E). It differs from the first measurement range based on the tissue identification step of acquiring the first shape data representing the shape of the tissue of the eye to be inspected in the first measurement range by performing segmentation processing on the tomographic image and the first shape data. Includes a specific step of obtaining second shape data representing the shape of the tissue of the eye to be inspected in the second measurement range.

According to such a method, the second measurement different from the first measurement range is obtained from the first shape data representing the shape of the tissue in the first measurement range obtained by performing the segmentation processing on the tomographic image of the eye to be inspected. Second shape data representing the shape of the tissue in the range is acquired. As a result, it becomes possible to identify the shape of the tissue of the eye to be inspected with high accuracy not only in the first measurement range but also in a wider range.

In the ophthalmic information processing method according to some embodiments, the specific step obtains the second shape data in the second measurement range by performing extrapolation processing based on the first shape data.

According to such a method, the extrapolation process is executed based on the first shape data in the first measurement range, so that the second shape data in the second measurement range is obtained. The shape of the tissue of the eye to be inspected can be specified with high accuracy in a range wider than the first measurement range.

The ophthalmic information processing methods according to some embodiments correspond to the refractive index obtained by objectively measuring the eye to be inspected and the shape of the tissue based on the second shape data acquired in the specific step. A calculation step is included in which the refractive index of the peripheral region of the region including the central fossa of the optometry is calculated based on the parameters representing the optical characteristics of the optometry.

According to such a method, it is possible to obtain the refractive power of the peripheral region including the fovea with high accuracy according to the shape of the fundus of the eye to be inspected.

The program according to some embodiments causes a computer to perform each step of the ophthalmic information processing method described in any of the above.

According to such a program, from the first shape data representing the shape of the tissue in the first measurement range obtained by performing the segmentation processing on the tomographic image of the eye to be inspected, the second measurement different from the first measurement range is performed. Second shape data representing the shape of the tissue in the range is acquired. As a result, it becomes possible to identify the shape of the tissue of the eye to be inspected with high accuracy not only in the first measurement range but also in a wider range.

<Others>
The embodiments shown above are merely examples for carrying out the present invention. A person who intends to carry out the present invention can make arbitrary modifications, omissions, additions, etc. within the scope of the gist of the present invention.

In some embodiments, a program is provided for causing a computer to execute not only the above-mentioned ophthalmic information processing method but also a control method for controlling the above-mentioned ophthalmic apparatus. Such a program can be stored in any computer-readable recording medium. Examples of the recording medium include semiconductor memory, optical disk, magneto-optical disk (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), magnetic storage medium (hard disk / floppy (registered trademark) disk / ZIP, etc.) and the like. Can be used. It is also possible to send and receive this program through a network such as the Internet or LAN.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Ophthalmic apparatus 10 Measuring unit 20 Refraction measuring unit 30 OCT unit 40 Alignment light projection unit 50 Control processing unit 60 Image forming unit 70 Data processing unit 71 Alignment processing unit 72 Analysis unit 721 Layer area identification unit 722 Specific unit 722A Model construction unit 722B Model expansion unit 73 Calculation unit 80 Control unit 90 Moving mechanism 100 Imaging unit BS1, BS2 Beam splitter E Eye to be inspected Ec Cornea Ef Fundus

Claims (15)

An acquisition unit that acquires a tomographic image of the eye to be inspected, which is formed based on scan data obtained by performing OCT measurement on the eye to be inspected.
A tissue identification unit that acquires first shape data representing the shape of the tissue of the eye to be inspected in the first measurement range by performing a segmentation process on the tomographic image.
Based on the first shape data, a specific part for obtaining the second shape data representing the shape of the tissue of the eye to be inspected in the second measurement range different from the first measurement range, and
Ophthalmic information processing device including. The ophthalmic information processing apparatus according to claim 1, wherein at least a part of the second measurement range overlaps with the first measurement range. The ophthalmic information processing apparatus according to claim 1 or 2, wherein the second measurement range includes the first measurement range. Any of claims 1 to 3, wherein the specific unit obtains the second shape data in the second measurement range by executing extrapolation processing based on the first shape data. The ophthalmic information processing apparatus according to paragraph 1. The specific unit according to any one of claims 1 to 3, wherein the approximate curve of the first shape data is specified, and the second shape data is obtained by using the specified approximate curve. The described ophthalmic information processing device. The ophthalmic information processing apparatus according to claim 5, wherein the specific unit obtains the second shape data by performing distortion correction processing on the approximate curve in a predetermined range of the second measurement range. .. The specific portion acquires correction shape data by performing actual shape correction on the first shape data, and performs ellipse fitting processing on the acquired correction shape data to obtain an ellipse shape. The ophthalmic information processing apparatus according to any one of claims 1 to 3, wherein the second shape data is obtained based on the above. The ophthalmic information processing apparatus according to claim 6, wherein the specific unit performs the distortion correction process based on standard data of the eye. The ophthalmic information processing apparatus according to any one of claims 1 to 8, wherein the tissue includes a predetermined layer region in the fundus. The refractive index obtained by objectively measuring the eye to be inspected and the parameter representing the optical characteristics of the eye to be inspected corresponding to the shape of the tissue based on the second shape data acquired by the specific portion. The ophthalmic information processing apparatus according to claim 9, further comprising a calculation unit for calculating the refractive index of the peripheral region of the region including the fovea centralis of the eye to be inspected. An optical system for performing the OCT measurement on the eye to be inspected,
The ophthalmic information processing apparatus according to any one of claims 1 to 10.
Ophthalmic equipment including. An acquisition step of acquiring a tomographic image of the eye to be inspected formed based on scan data obtained by performing OCT measurement on the eye to be inspected, and
A tissue identification step of acquiring first shape data representing the shape of the tissue of the eye to be inspected in the first measurement range by performing a segmentation process on the tomographic image.
A specific step of obtaining second shape data representing the shape of the tissue of the eye to be inspected in a second measurement range different from the first measurement range based on the first shape data, and
Ophthalmic information processing methods including. The ophthalmic information processing method according to claim 12, wherein the specific step obtains the second shape data in the second measurement range by executing extrapolation processing based on the first shape data. .. The refractive index obtained by objectively measuring the eye to be inspected, and the parameters representing the optical characteristics of the eye to be inspected corresponding to the shape of the tissue based on the second shape data acquired in the specific step. The ophthalmic information processing method according to claim 12 or 13, wherein the calculation step of calculating the refractive index of the peripheral region of the region including the fovea centralis of the eye to be inspected is included. A program comprising causing a computer to execute each step of the ophthalmic information processing method according to any one of claims 12 to 14.

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