JP7148114B2 - ophthalmic equipment - Google Patents

Description

The technology disclosed herein relates to an ophthalmic device. More specifically, the present invention relates to an ophthalmologic apparatus that captures a tomographic image of the anterior segment of an eye to be examined.

2. Description of the Related Art An ophthalmologic apparatus that captures a tomographic image of the anterior segment of an eye to be examined has been developed. For example, an ophthalmologic apparatus includes a measurement optical system that irradiates light from a light source into the eye to be examined and guides the reflected light, and a reference optical system that irradiates a reference surface with light from the light source and guides the reflected light. ing. During measurement, a tomographic image of the anterior segment of the subject's eye is generated from interference light obtained by synthesizing the reflected light guided by the measurement optical system and the reflected light guided by the reference optical system. For example, Patent Literature 1 discloses an example of an ophthalmic apparatus.

JP 2016-41162 A

Since this type of ophthalmologic apparatus generates a tomographic image of the anterior segment of the subject's eye, it is possible to observe the state of each part (for example, the crystalline lens) of the anterior segment. However, each part of the anterior segment is composed of a plurality of tissues. In order to diagnose an eye to be examined, it is required to grasp the state of tissue in each part of the anterior segment of the eye. The present specification provides an ophthalmologic apparatus capable of generating an image that allows easy understanding of the tissue state of each region of the anterior segment.

The ophthalmologic apparatus disclosed in this specification includes an imaging unit that captures a tomographic image of the anterior segment of an eye to be examined, and a computing unit. The calculation unit detects a boundary between tissues in a tomographic image of the anterior segment of the eye to be inspected captured by the imaging unit, and performs boundary detection processing to detect the boundary between tissues in the tomographic image of the anterior segment of the eye to be inspected. An extraction process for extracting a tissue defined by a boundary or a specific area set in the vicinity of the tissue, and front image generation for generating a front image of the specific area using image data of the specific area extracted by the extraction process. It is configured to be able to execute processing.

In the ophthalmic apparatus described above, by detecting boundaries between tissues, it is possible to extract only specific regions such as tissues demarcated by the detected boundaries and the vicinity of the detected boundaries. Also, the front image can be generated using only the image data of the extracted specific region. As a result, a front image composed only of a specific region such as tissue (for example, cortex, capsule, etc.) that constitutes the crystalline lens is generated. For this reason, it becomes easier to observe a portion that is difficult to recognize due to the presence of areas other than the specific area in a normal front image, and the state of the specific area can be observed with high accuracy.

1 is a diagram showing a schematic configuration of an optical system of an ophthalmologic apparatus according to an embodiment; FIG. FIG. 2 is a diagram showing a schematic configuration of a scanning-alignment optical system; 1 is a block diagram showing a control system of an ophthalmologic apparatus according to an embodiment; FIG. 4 is a flow chart showing an example of processing for measuring the anterior segment of a normal eye to be examined (an eye to be examined in which an intraocular lens is not inserted). FIG. 4 is a diagram for explaining a radial scan method; FIG. 4 is a diagram for explaining a raster scan method; FIG. 4 is a schematic diagram showing a state in which a boundary between tissues of the crystalline lens is detected in a tomographic image; FIG. 4 is a diagram for explaining the procedure for creating an en-face image of the anterior cortex, (a) showing a tomographic image of the lens, and (b) showing an en-face image of the anterior cortex. Schematic diagram showing a colored two-dimensional tomographic image of a nucleus. The figure which shows an example of the image displayed on a touch panel. 4 is a flow chart showing an example of processing for measuring the anterior segment of an eye into which a toric intraocular lens is inserted. FIG. 4 is a diagram for explaining the process of capturing a tomographic image of the anterior segment of the eye by raster scanning based on the corneal shape of the subject's eye, (a) showing a corneal shape map of the subject's eye, and (b) showing the cornea. The scan direction along the strong principal axis of the eye to be examined calculated from the shape map is shown. FIG. 10 is a tomographic image showing a state in which the boundary between the tissue in the subject's eye and the toric intraocular lens is detected. En-face image consisting only of the near-surface region of the toric intraocular lens. The figure which shows an example of the analysis result displayed on a touch panel.

The main features of the embodiments described below are listed. It should be noted that the technical elements described below are independent technical elements, and exhibit technical usefulness alone or in various combinations, and are limited to the combinations described in the claims as filed. not a thing

(Feature 1) The ophthalmologic apparatus disclosed in the present specification includes a display unit that displays a tomographic image of the anterior segment of the subject's eye captured by the imaging unit, and a tomographic image that is operated by the examiner and displayed on the display unit. and a specific area setting unit that sets the specific area in the above. The calculation unit may generate a front image of the specific area set by the specific area setting unit. According to such a configuration, by setting the specific region by the inspector, it is possible to extract the site that the inspector wants to observe, and to generate a front image composed only of the site desired by the inspector. . This allows the inspector to accurately observe the desired site.

(Feature 2) In the ophthalmologic apparatus disclosed in this specification, the calculation unit is configured to be able to further execute analysis processing for analyzing the state within the specific region based on the front image generated by the front image generation processing. may According to such a configuration, the calculation unit analyzes the state of the specific area using the front image composed only of the specific area. Since there is no region other than the specific region in the generated front image, for example, the state of turbidity in the specific region can be analyzed with high accuracy.

(Feature 3) In the ophthalmologic apparatus disclosed in the present specification, the boundary detection processing detects the boundary between the inserted toric intraocular lens and the tissue of the eye to be examined in the tomographic image of the eye to be examined in which the toric intraocular lens is inserted. You may The extraction process may extract a specific region set near the boundary between the inserted toric intraocular lens and the tissue of the eye to be examined. The calculation unit may be configured to be capable of further executing toric axis direction calculation processing for calculating the toric axis direction of the toric intraocular lens based on the front image generated by the front image generation processing. According to such a configuration, by extracting a specific region set near the boundary between the tissue of the eye to be examined and the toric intraocular lens, a front image composed only of the region near the surface of the toric intraocular lens can be obtained. generated. This enables accurate observation of the surface of the toric intraocular lens. In addition, by using a front image composed only of the area near the surface of the toric intraocular lens, for example, a mark indicating the toric axis direction of the toric intraocular lens can be easily detected. can be easily calculated. This makes it possible to accurately grasp the insertion position of the toric intraocular lens.

(Feature 4) In the ophthalmologic apparatus disclosed in the present specification, the imaging unit sets the scanning direction based on the corneal shape of the subject's eye, and captures a tomographic image of the anterior segment of the subject's eye for use in boundary detection processing. You may According to such a configuration, by setting the scanning direction when capturing a tomographic image based on the corneal shape of the eye to be inspected, it is possible to image the eye to be inspected in accordance with the condition of the eye to be inspected, such as astigmatism. can. As a result, the toric axis direction of the toric intraocular lens can be calculated more accurately.

(Feature 5) In the ophthalmologic apparatus disclosed in the present specification, the imaging unit may capture a tomographic image of the anterior segment of the subject's eye using a raster scan method. The scanning direction of the raster scanning method may be a direction substantially parallel to the strong principal radius of the cornea of the subject's eye. According to such a configuration, by setting the scanning direction in a direction substantially parallel to the strong principal axis of the cornea of the subject's eye, the scanning direction substantially coincides with the toric axis of the toric intraocular lens. Therefore, it is possible to prevent the mark or the like indicating the toric axis direction from being shifted, and the axial direction of the intraocular lens can be calculated more accurately.

(Feature 6) The ophthalmologic apparatus disclosed in the present specification provides a display in which a corneal shape map indicating the corneal shape and an image indicating the toric axis direction of the toric intraocular lens calculated by the toric axis direction calculation process are displayed in an overlapping manner. A part may be further provided. With such a configuration, it is possible to easily grasp the displacement of the inserted toric intraocular lens in the toric axis direction.

The ophthalmologic apparatus 1 according to the embodiment will be described below. The ophthalmologic apparatus 1 captures a tomographic image of the anterior segment of the subject's eye E using optical coherence tomography (OCT). As shown in FIG. 1, the ophthalmologic apparatus 1 includes a light source 10, an interference optical system 14 that causes interference between the reflected light reflected from the eye E to be examined and the reference light, and a K-clock generator that generates a K-clock signal. It has 50.

The light source 10 is a wavelength swept light source, and the wavelength of the emitted light changes in a predetermined cycle. When the wavelength of the light emitted from the light source 10 changes, of the light reflected from each part in the depth direction of the eye to be inspected E, the reflected light causing interference with the reference light corresponds to the wavelength of the emitted light. The reflection position changes in the depth direction of the eye E to be examined. Therefore, by measuring the interference light while changing the wavelength of the emitted light, it is possible to specify the position of each part (for example, the cornea, the lens, etc.) inside the eye E to be examined.

Light output from the light source 10 is input to the fiber coupler 12 through an optical fiber. The light input to the fiber coupler 12 is demultiplexed by the fiber coupler 12 and output to the fiber coupler 16 and the K-clock generator 50 through the optical fiber. The K-clock generator 50 will be described later.

The interference optical system 14 includes a measurement optical system that irradiates the inside of the eye E to be inspected with light from the light source 10 and generates reflected light, a reference optical system that generates reference light from the light from the light source 10, and a measurement optical system. It is composed of a balance detector 40 for detecting interference light obtained by synthesizing the guided reflected light and the reference light guided by the reference optical system.

The measurement optical system is composed of a fiber coupler 16, a circulator 18, and a scanning-alignment optical system 20. FIG. Light output from the light source 10 and input to the fiber coupler 16 via the fiber coupler 12 is demultiplexed into measurement light and reference light at the fiber coupler 16 and output. The measurement light output from the fiber coupler 16 is input to the circulator 18 through the optical fiber. The measurement light input to the circulator 18 is output to the scanning-alignment optical system 20 . The scanning-alignment optical system 20 irradiates the subject's eye E with the measurement light output from the circulator 18 and outputs reflected light from the subject's eye E to the circulator 18 . The reflected light input to the circulator 18 is input to one input port of the fiber coupler 38 . The scanning-alignment optical system 20 will be detailed later.

A reference optical system comprises a fiber coupler 16 , a circulator 22 and a reference section 24 . The reference light output from the fiber coupler 16 is input to the circulator 22 through the optical fiber. The reference light input to the circulator 22 is output to the reference section 24 . The reference section 24 is composed of collimator lenses 26 and 28 and a reference mirror 30 . The reference light output to the reference section 24 is reflected by the reference mirror 30 via the collimator lenses 26 and 28 and output from the reference section 24 via the collimator lenses 26 and 28 again. The reference light output from the reference unit 24 is output to the circulator 22 . The collimator lens 28 and the reference mirror 30 are configured to move forward and backward with respect to the collimator lens 26 by a second driving device 54 (see FIG. 3). The second driving device 54 moves the collimator lens 28 and the reference mirror 30 to change the optical path length of the reference optical system. Thereby, the optical path length of the reference optical system can be adjusted so as to substantially match the optical path length of the measurement optical system. The reference light input to the circulator 22 is input to the other input port of the fiber coupler 38 via the polarization controller 36 . The polarization controller 36 is an element that controls polarization of reference light input to the fiber coupler 38 . The polarization controller 36 can be of a paddle type, an in-line type, or the like, which is used in known ophthalmologic apparatuses, so detailed description thereof will be omitted.

The fiber coupler 38 combines the input reflected light from the eye to be inspected E and the reference light to generate interference light. The fiber coupler 38 splits the generated interference light into two interference lights with a phase difference of 180 degrees, and inputs them to the balance detector 40 . The balance detector 40 performs differential amplification and noise reduction processing on the two interference lights that are input from the fiber coupler 38 and whose phases differ by 180 degrees, and converts them into electrical signals (interference signals). Balance detector 40 outputs an interference signal to computing device 60 .

Here, the configuration of the scanning-alignment optical system 20 will be described with reference to FIG. The scanning-alignment optical system 20 includes a scanning optical system, an anterior segment imaging system, a fixation target optical system, and an alignment optical system.

As shown in FIG. 2, the scanning optical system comprises a collimator lens 102, a galvanometer scanner 104, a hot mirror 106 and an objective lens . The measurement light output from the circulator 18 (see FIG. 1) is output to the galvanometer scanner 104 via the collimator lens 102 . The galvanometer scanner 104 is configured to be tilted by a first driving device 52 (see FIG. 3). is scanned. The measurement light emitted from the galvanometer scanner 104 is applied to the hot mirror 106 and reflected at an angle of 90 degrees. The measurement light applied to the hot mirror 106 is applied to the subject's eye E via the objective lens 108 . Reflected light from the subject's eye E is input to the circulator 18 via the objective lens 108 , the hot mirror 106 , the galvanometer scanner 104 and the collimator lens 102 , contrary to the above.

The anterior segment imaging system includes two illumination light sources 110 , an objective lens 108 , a hot mirror 106 , a cold mirror 112 , an imaging lens 114 , a CCD camera 116 and an optical controller 118 . The two illumination light sources 110 irradiate the front surface of the eye E with illumination light in the visible light region. Reflected light from the subject's eye E passes through the objective lens 108 , the hot mirror 106 , the cold mirror 112 and the imaging lens 114 and is input to the CCD camera 116 . As a result, a front image of the subject's eye E is captured. The captured image data is image-processed by the optical control unit 118 and displayed on the touch panel 56 .

The fixation target optical system includes a fixation target light source 120 , cold mirrors 122 and 124 , a relay lens 126 , a half mirror 128 , a cold mirror 112 , a hot mirror 106 and an objective lens 108 . Light from fixation target light source 120 passes through cold mirrors 122 and 124 , relay lens 126 and half mirror 128 and is reflected by cold mirror 112 . The light reflected by the cold mirror 112 passes through the hot mirror 106 and the objective lens 108 and illuminates the eye E to be examined. By having the subject fixate the light from the fixation target light source 120, it is possible to prevent the eyeball (that is, the subject's eye E) from moving as much as possible.

The alignment optical system is composed of an XY-direction position detection system and a Z-direction position detection system. The XY-direction position detection system is used to detect the XY-direction position of the subject's eye E (specifically, the corneal vertex) (that is, vertical and horizontal positional deviation with respect to the ophthalmologic apparatus 1). The Z-direction position detection system is used to detect the position of the corneal vertex of the subject's eye E in the front-back direction (Z-direction).

The XY direction position detection system includes an XY position detection light source 130, a cold mirror 124, a relay lens 126, a half mirror 128, a cold mirror 112, a hot mirror 106, an objective lens 108, an imaging lens 132, A position sensor 134 is provided. The XY position detection light source 130 emits alignment light for position detection. Alignment light emitted from the XY position detection light source 130 is reflected by the cold mirror 124 , passes through the relay lens 126 and half mirror 128 , and is reflected by the cold mirror 112 . The light reflected by the cold mirror 112 passes through the hot mirror 106 and the objective lens 108 and irradiates the anterior segment (cornea) of the eye E to be examined.

Since the corneal surface of the eye E to be inspected is spherical, the alignment light is reflected by the corneal surface so as to form a bright spot image inside the corneal vertex of the eye E to be inspected. The reflected light from the corneal surface enters the objective lens 108 and is reflected by the cold mirror 112 via the hot mirror 106 . Reflected light reflected by the cold mirror 112 is reflected by the half mirror 128 and is input to the position sensor 134 via the imaging lens 132 . The position of the corneal vertex (that is, the position in the X direction and the Y direction) is detected by the position sensor 134 detecting the position of the bright spot.

A detection signal from the position sensor 134 is input to the arithmetic unit 60 via the optical control unit 118 . In this case, the position sensor 134 and the anterior segment imaging system are aligned, and a predetermined (regular) image acquisition position of the corneal vertex (position to be tracked when obtaining a tomographic image) is set. there is The normal image acquisition position of the corneal vertex is, for example, a point that coincides with the center position of the captured image of the CCD camera 116 . Based on the detection by the position sensor 134, the computing device 60 calculates the amount of positional deviation of the detected corneal vertex (bright spot) with respect to the normal image acquisition position in the X direction and the Y direction.

The Z-direction position detection system includes a Z-position detection light source 140 , an imaging lens 142 and a line sensor 144 . The Z-position detection light source 140 irradiates the subject's eye E with detection light (slit light or spot light) from an oblique direction. Oblique reflected light from the cornea of the subject's eye E is incident on the line sensor 144 via the imaging lens 142 . At this time, the incident position of the reflected light incident on the line sensor 144 differs depending on the position of the subject's eye E in the front-rear direction (Z direction) with respect to the ophthalmologic apparatus 1 . Therefore, the position of the subject's eye E in the Z direction with respect to the ophthalmologic apparatus 1 is detected by detecting the incident position of the reflected light. A detection signal from the line sensor 144 is input to the arithmetic device 60 .

A K-clock generator 50 (see FIG. 1) generates a sample clock (K-clock ) to optically generate the signal. The generated K-clock signal is then output toward the arithmetic device 60 . As a result, the computation device 60 samples the interference signal based on the K-clock signal, thereby suppressing the distortion of the interference signal and preventing deterioration of the resolution. In this embodiment, the interference signal sampled at the timing defined by the K-clock signal is input to the arithmetic unit 60, but the configuration is not limited to this. For example, the arithmetic unit 60 may perform a process of scaling data sampled at regular time intervals with respect to a previously known function indicating frequency with respect to sweep time or a sweep profile acquired at the same time. Note that the interference optical system 14 and the K-clock generator 50 are an example of the "imager".

Next, the configuration of the control system of the ophthalmologic apparatus 1 of this embodiment will be described. As shown in FIG. 3 , the ophthalmologic apparatus 1 is controlled by an arithmetic device 60 . The arithmetic unit 60 is configured by a microcomputer (microprocessor) including a CPU, ROM, RAM, and the like. The computing device 60 includes a light source 10, a first driving device 52, a second driving device 54, an illumination light source 110, a fixation target light source 120, an XY position detection light source 130, a Z position detection light source 140, Optical controller 118, line sensor 144, balance detector 40, K-clock generator 50, and touch panel 56 are connected.

The computing device 60 controls the ON/OFF of the light source 10 and drives the galvanometer scanner 104 and the reference unit 24 by controlling the first driving device 52 and the second driving device 54 . Further, the computation device 60 receives an interference signal corresponding to the intensity of the interference light detected by the balance detector 40 and a K-clock signal generated by the K-clock generator 50 . Arithmetic unit 60 samples the interference signal from balance detector 40 based on the K-clock signal. Then, the arithmetic unit 60 performs Fourier transform on the sampled interference signal to obtain the respective regions (eg, cornea, anterior chamber, lens, etc.) and tissues (eg, lens nucleus, cortex, capsule, etc.) of the eye E to be examined. Identify the location of Data and calculation results input to the arithmetic device 60 are stored in a memory (not shown).

Further, the computing device 60 controls ON/OFF of the illumination light source 110 , fixation target light source 120 , and XY position detection light source 130 . The computing device 60 receives the front image of the subject's eye E photographed by the CCD camera 116 and processed by the optical controller 118, and the corneal vertex (bright spot) detected by the position sensor 134 via the optical controller 118. Enter the location of Based on the input front image of the eye E to be inspected and the position of the corneal vertex (bright point), the computing device 60 calculates the displacement amount of the corneal vertex (bright point) in the XY direction. The computing device 60 receives the detection signal from the line sensor 144 and calculates the amount of deviation of the subject's eye E from the ophthalmologic apparatus 1 in the Z direction. The computing device 60 calculates the amount of positional deviation of the corneal vertex (bright spot) in the X and Y directions detected by the XY direction position detection system and the positional deviation of the subject's eye E in the Z direction detected by the Z direction position detection system. Based on the amount, the main body driving section (not shown) is controlled so as to set all the displacement amounts to 0, and the main body of the ophthalmologic apparatus 1 is moved with respect to the holding base (not shown).

Furthermore, the computing device 60 controls the touch panel 56 . The touch panel 56 is a display device that provides the examiner with various types of information about the measurement results and analysis results of the eye to be examined E, and is a user interface that receives instructions and information from the examiner. For example, the touch panel 56 can display an image of each tissue of the crystalline lens of the subject's eye E or an intraocular lens generated by the arithmetic device 60, an analysis result, and the like. Also, the touch panel 56 can input various settings of the ophthalmologic apparatus 1 . Although the ophthalmologic apparatus 1 of this embodiment includes the touch panel 56, the configuration is not limited to this. Any configuration may be used as long as the above information can be displayed and input, and a monitor and an input device (for example, a mouse, a keyboard, etc.) may be provided.

Processing for measuring the anterior segment of the subject's eye E using the ophthalmologic apparatus 1 will be described with reference to FIGS. 4 to 15. FIG. The ophthalmologic apparatus 1 can measure the anterior segment of the subject's eye E and analyze each tissue of the anterior segment (for example, each tissue constituting the crystalline lens). For example, by analyzing the lens for each tissue, the opacity state of the lens can be analyzed in detail. Further, the ophthalmologic apparatus 1 can measure the anterior segment of the subject's eye E into which an intraocular lens (IOL, hereinafter also referred to as "IOL") is inserted, and analyze the IOL insertion position and the like. Hereinafter, an eye to be examined having a crystalline lens into which an IOL is not inserted may be referred to as a "normal eye to be examined" in order to distinguish it from an eye into which an IOL is inserted. As examples of measurement of the eye to be examined E by the ophthalmologic apparatus 1, processing for measuring a normal anterior segment of the eye to be examined E and processing for measuring an anterior segment of the eye to be examined E into which an IOL is inserted will be described below.

First, an example of normal processing for measuring the anterior segment of the subject's eye E will be described with reference to FIGS. 4 to 10. FIG. More specifically, a process for analyzing each tissue of the lens of the eye E to be inspected and grasping the opacity state of the lens in detail will be described.

As shown in FIG. 4, first, the computing device 60 acquires a tomographic image of the anterior segment of the subject's eye E (S12). The process of acquiring a tomographic image of the anterior segment of the eye E to be examined is performed according to the following procedure. First, when an examiner inputs an instruction to start examination from the touch panel 56 , the arithmetic device 60 aligns the eye E to be examined and the ophthalmologic apparatus 1 . Alignment is performed based on the amount of deviation in the XY and Z directions detected by the alignment optical system. Specifically, the computing device 60 calculates the amount of positional deviation of the corneal vertex (bright spot) in the X and Y directions detected by the XY direction position detection system, and the positional deviation of the subject's eye E detected by the Z direction position detection system. The main body of the ophthalmologic apparatus 1 is moved with respect to a holding table (not shown) so that the amount of positional deviation in the Z direction becomes zero.

When the alignment is completed, the computing device 60 captures a tomographic image of the anterior segment of the eye E to be examined. In this embodiment, the measurement of the anterior segment of the subject's eye E in step S12 is performed by a radial scan method. Thereby, a tomographic image of the anterior segment is acquired over the entire region. That is, as shown in FIG. 5, the B-scanning direction is set in the radial direction from the corneal vertex of the subject's eye E, and the C-scanning direction is set as the circumferential direction to capture the tomographic image. In the present embodiment, tomographic images are taken radially in 128 directions (specifically, in 128 directions at equal intervals in the circumferential direction) by a radial scan method. The arithmetic unit 60 stores the acquired (captured) tomographic image data into a memory. Note that the method for capturing a tomographic image of the lens is not limited to the radial scan method. It is sufficient if a tomographic image of the crystalline lens can be acquired over the entire area, and for example, as shown in FIG. 6, it may be captured by a raster scan method. That is, the B-scanning direction may be set in the horizontal direction with respect to the eye E to be examined, and the C-scanning direction may be set in the vertical direction to capture the tomographic image.

When the tomographic image of the anterior segment of the subject's eye E is acquired in step S12, the computing device 60 detects the boundary between the tissues of the lens based on the luminance information included in each piece of interference signal information (S14). As shown in FIG. 7, the arithmetic unit 60 calculates the boundary L1 between the anterior capsule and the anterior chamber (that is, the front surface of the lens), the boundary L2 between the anterior capsule and the cortex, and the boundary L3 between the cortex and the nucleus. , L4, the boundary L5 between the cortex and the posterior capsule, and the boundary L6 between the posterior capsule and the vitreous body (that is, the posterior surface of the lens). That is, when the measurement light passes through the inside of the crystalline lens, it is partially reflected at each of the boundaries L1 to L6 of each tissue. The interference signal information includes reflected light components reflected at these boundaries L1 to L6. In step S14, boundaries L1 to L6 between tissues in the lens are detected based on these signal components included in the interference signal information.

Next, the arithmetic unit 60 extracts each tissue defined by the boundaries L1 to L6 between the tissues of the lens detected in step S14 (S16). Each tissue of the lens includes an anterior capsule, cortex, nucleus, and posterior capsule. In a tomographic image, the cortex is often divided by the nucleus into an anterior chamber side (upper side in FIG. 7) and a vitreous body side (lower side in FIG. 7). Therefore, hereinafter, of the cortices divided by the nucleus, the cortex located on the anterior chamber side may be referred to as the "anterior cortex", and the cortex located on the vitreous side may be referred to as the "posterior cortex". Therefore, as each tissue of the lens, the anterior capsule, anterior cortex, nucleus, posterior cortex, and posterior capsule can be specified from the anterior chamber side to the vitreous body side. In step S16, the arithmetic unit 60 extracts the area defined by the boundaries L1 and L2 as the anterior capsule, the area defined by the boundaries L2 and L3 as the anterior cortex, and the area defined by the boundaries L3 and L4. is extracted as the nucleus, the area between boundaries L4 and L5 is extracted as the posterior cortex, and the area defined by boundaries L5 and L6 is extracted as the posterior capsule.

Next, the computing device 60 creates a two-dimensional image of each tissue extracted in step S16 (S18). A two-dimensional image is created as a front image by extracting only the anterior capsule, the anterior cortex, the posterior cortex, and the posterior capsule among the above-described tissues. On the other hand, the nucleus is created as a tomographic image. In the conventional method of observation using a slit lamp microscope, an examiner observes the state of the nucleus using a slit lamp. In this case, the examiner observes the nucleus in a state similar to a tomographic image. On the other hand, in the conventional method, for tissues other than the nucleus (anterior capsule, anterior cortex, posterior cortex, and posterior capsule), the fundus of the subject's eye E is irradiated with illumination light, and the reflected light from the fundus is used for transillumination. Observed by law. In this case, the examiner observes tissues other than the nucleus (anterior capsule, anterior cortex, posterior cortex, and posterior capsule) in a state close to a frontal image. When creating a two-dimensional image of each tissue, the two-dimensional image of the nucleus is used as a tomographic image, and the two-dimensional images of other tissues (anterior capsule, anterior cortex, posterior cortex, and posterior capsule) are used as frontal images. Accordingly, the examiner can diagnose each tissue in a state close to the conventional observation method.

Here, the creation of the frontal image will be described using the anterior cortex as an example. The computing device 60 uses the region (the region between boundaries L2 and L3) specifying the anterior cortex extracted from each tomographic image to create a frontal image composed only of the anterior cortex. The front image is, for example, an En-face image. Specifically, for the three-dimensional data, the maximum value and average value are calculated in the depth direction for each A-scan, and the three-dimensional data is compressed into a two-dimensional en-face image.

For example, as shown in FIG. 8A, the computing device 60 averages the brightness in the depth direction indicated by the arrow for each A-scan in the region between the boundaries L2 and L3 specifying the anterior cortex. Then, as shown in FIG. 8(b), the arithmetic device 60 displays the averaged brightness as dots to create an en-face image. For the anterior capsule, posterior cortex, and posterior capsule, the arithmetic unit 60 also creates an en-face image displaying only the anterior capsule, posterior cortex, or posterior capsule in the same procedure as for the anterior cortex. In order to construct an En-face image composed only of a specific tissue (eg, anterior cortex), tissues other than the tissue (eg, anterior cortex) in the En-face image (eg, anterior capsule, nucleus, posterior cortex) and posterior capsule) are not superimposed and displayed. Therefore, the examiner can easily and accurately grasp the state of the tissue.

Next, generation of a two-dimensional tomographic image of the nucleus will be described. The arithmetic device 60 colors the tomographic image of the nucleus using a plurality of colors based on the luminance information. The tomographic images used at this time are a horizontal tomographic image and a plurality of tomographic images adjacent to the tomographic image in the circumferential direction (in this embodiment, ±1.4 degrees and ±2.8 degrees with respect to the tomographic image). A total of four tomographic images captured in the direction of ) may be averaged to remove speckle noise. For example, in a region where opacity occurs in the nucleus, the brightness of the tomographic image is high, and the greater the degree of opacity, the higher the brightness. Therefore, the luminance information of each pixel is replaced with the hue so that the color changes as the luminance increases. For example, pixels with low luminance are colored green, and as the luminance increases, the color gradually changes from green to yellow. Then, the color is changed from yellow to red as the brightness increases. For example, if the cataract is advanced (eg, WHO classification grade 4 or higher), the pixel is replaced with red. By coloring the tomographic image of the nucleus in this way, pixels having the same luminance information in the tomographic image are colored with the same color.

In the nucleus, turbidity is more likely to occur in the central portion of the cross section than in the outer peripheral portion. Therefore, in the tomographic image of the subject's eye E in which the cataract is progressing, if each pixel is replaced with the hue described above, the central portion of the nucleus is colored red, and gradually approaches green from the central portion toward the outer peripheral portion. colored in color. For example, as shown in FIG. 9, when cataract progresses in the nucleus, in the tomographic image, the centralmost region R1 is colored red, and the region R2 adjacent to the outside of region R1 is colored orange. The region R3, which is colored, is colored yellow and the outermost region R4 is colored green.

When viewed using a conventional slit lamp microscope, the nuclei are observed in different colors depending on the progress of the cataract. That is, when the degree of cataract progression is low, the nucleus is observed as a color close to white. By coloring the nucleus based on the luminance information as described above, the examiner can grasp the state of the nucleus with a color close to that obtained by the conventional observation method. In this embodiment, the luminance information of each pixel is replaced with the hue. However, based on the average value of the luminance information including the luminance information around the pixel, the pixel is replaced with the set hue. good too. Also, in this embodiment, each pixel is colored using a hue that changes from green to red, but the color used when replacing luminance information is not particularly limited. For example, the colors observed using a conventional slit-lamp microscope (i.e., white, yellow, brown) may be substituted to convert the image to an image equivalent to that observed using a slit-lamp microscope. .

In this embodiment, the arithmetic unit 60 extracts the anterior capsule, anterior cortex, nucleus, posterior cortex, and posterior capsule, and generates two-dimensional images (en-face images, colored tomographic images) of each. However, it is not limited to such a configuration. The computing device 60 may extract only the tissue specified by the examiner from among the above tissues, and generate only the two-dimensional image of the specified tissue.

Next, each tissue is graded based on the two-dimensional image created in step S18 (S20). For example, grading is performed based on WHO classification.

Specifically, the cortex (anterior cortex and posterior cortex) is classified based on the opacity rate (%) in the circumference of the en-face image. In addition, opacity in the center of the cortex is classified according to the presence or absence of opacity within 3 mm from the center of the pupil. For example, in the en-face image 74 (see FIG. 10) of the anterior cortex, it is assumed that the ratio of opacity to the circumference is calculated to be approximately 30%. According to the WHO classification, when the percentage of circumferential opacity in the cortex is 25% or more and less than 50%, it is classified as Grade 2. Assume that it is determined that the en-face image 74 of the anterior cortex has opacity within 3 mm of the center of the pupil. In this case, in step S20, the anterior cortex is classified as Grade 2 and with opacification in the center of the anterior cortex.

In addition, the nucleus is classified so as to correspond to the grading method determined by comparison with the reference photograph of WHO classification. Specifically, the nucleus is graded based on which WHO classification reference photograph corresponds to the nucleus brightness information (that is, the color colored in step S18) in the tomographic image. For example, in the colored tomographic image 82 of the nucleus (see FIG. 10), assume that the central portion of the nucleus is colored yellow. When a nucleus is colored yellow in a tomographic image, it is assumed that the pixel corresponds to the color of the opacity site in reference photograph 2 (grade 1) in the reference photograph of WHO classification. In this case, the nucleus is classified as grade 1 in step S20.

As for the posterior capsule, the posterior capsule is classified based on the opacity size (mm). For example, in the En-face image 78 (see FIG. 10) of the posterior capsule, the opacity size is calculated to be approximately 4 mm. According to the WHO classification, if the size of the turbidity is 3 mm or more, it is classified as grade 3. Therefore, in step S20, the posterior capsule is classified as Grade 3.

Finally, the computing device 60 outputs the two-dimensional image generated in step S18 to the touch panel 56 (S22). For example, FIG. 10 shows an example of a two-dimensional image displayed on the touch panel 56. As shown in FIG. As shown in FIG. 10, the touch panel 56 displays an en-face image 72 of the anterior capsule, an en-face image 74 of the anterior cortex, an en-face image 76 of the posterior cortex, and an en-face image of the posterior capsule. 78 and a tomographic image 82 in which the nucleus is colored are displayed. Further, as shown in FIG. 10, the tomographic image 80 obtained in step S12 may be displayed on the touch panel 56 together with the two-dimensional images 72 to 78, 82 created in step S18. Thus, by displaying a two-dimensional image created for each tissue, the condition of the lens can be observed in detail and with high accuracy.

Next, an example of processing for measuring the anterior segment of the subject's eye E into which the IOL is inserted will be described with reference to FIGS. 11 to 15. FIG. Specifically, a process for analyzing the anterior ocular segment of the subject's eye E into which the toric IOL is inserted and grasping the toric axis angle of the inserted toric IOL will be described. On the surface of the toric IOL, marks M indicating the position of the toric axis (hereinafter also referred to as axis marks M) are marked on both ends of the toric IOL on the weak principal axis (that is, the periphery of the toric IOL). (See FIG. 14). In order to correct the astigmatism of the subject's eye E using the toric IOL, it is necessary to fix the toric IOL within the subject's eye E so that the weak principal axis of the toric IOL substantially coincides with the strong principal axis of the subject's eye E. There is That is, the two axis marks M of the inserted toric IOL need to be positioned on the strong principal axis of the eye E to be examined. Therefore, the axis mark M of the toric IOL inserted in the subject's eye E is detected, and it is analyzed whether or not the toric IOL is fixed at an accurate position.

As shown in FIG. 11, first, the computing device 60 measures the corneal shape of the subject's eye E (S42). Measurement of the corneal shape of the subject's eye E can be performed by various methods. For example, the corneal shape of the eye E to be examined is obtained from a tomographic image of the anterior segment of the eye E to be examined. That is, a tomographic image of the anterior segment of the subject's eye E is obtained in the same manner as in step S12 described above. Note that the tomographic image used for measuring the corneal shape may be captured by the radial scan method or the raster scan method, as in step S12. Next, the computing device 60 calculates the corneal shape of the eye E to be examined from each of the tomographic images (for example, 16 images) of the eye E to be examined. Specifically, the shape of the anterior corneal surface is calculated from each tomographic image, the radius of curvature at each position on the anterior corneal surface is calculated from the calculated shape of the anterior corneal surface, and the refractive power at each position is calculated from the radius of curvature. Thus, a corneal power map (see FIG. 12(a)) showing the distribution of the corneal power of the eye E to be examined is calculated. In the above example, the radius of curvature was calculated from the shape of the anterior surface of the cornea, but the radius of curvature may be calculated from the shape of the anterior and posterior surface of the cornea. Also, the corneal shape of the eye E to be examined may be acquired from the reflected image of the pattern light projected onto the corneal surface of the eye E to be examined. That is, the computing device 60 projects concentric circular pattern light onto the corneal surface of the eye E to be examined, and captures a reflected image from the corneal surface. Next, the computing device 60 measures the corneal shape of the subject's eye E based on the photographed reflected image. In the above example, a tomographic image of the anterior segment of the subject's eye E is acquired, and the corneal shape is calculated from the acquired tomographic image, but the configuration is not limited to this. Since the corneal shape of the subject's eye E hardly changes in a short period of time, for example, a corneal shape map calculated for the same subject's eye E may be obtained. The computing device 60 calculates a strong principal radial line 90 (see FIG. 13) of the subject's eye E based on the measured (or acquired) corneal shape map.

Next, the arithmetic device 60 captures a tomographic image of the subject's eye E using a raster scan method (S44). As described above, in the raster scan method, the B scan direction is set horizontally with respect to the subject's eye E (see FIG. 6). As shown in FIG. 12(b), in step S44, when a tomographic image of the eye to be examined E is captured by the raster scan method, the B scan direction is set parallel to the strong principal axis 90 of the eye to be examined E calculated in step S42. direction.

If the toric IOL is fixed at the correct position within the eye E to be examined, that is, if the toric IOL is fixed such that the toric axis of the toric IOL substantially coincides with the strong principal axis 90 of the eye E to be examined, 2 All of the axis marks M marked at the locations are positioned on the strong principal axis 90 of the eye E to be examined. Further, since the toric IOL is fixed so that the axis mark M is positioned on the strong principal axis 90 of the eye E to be examined, even if the toric axis of the toric IOL is fixed in a deviated state, the axis mark M is likely to be located near the strong principal radial line 90 of the eye E to be examined. By capturing a tomographic image with the B scan direction set in a direction parallel to the strong principal axis 90 of the eye to be examined E, both of the axis marks M marked at two locations are captured in one tomographic image. or taken over multiple images taken closely spaced in time. When taking a tomographic image of the entire eye E to be inspected, a plurality of images are taken, so it takes time from the start to the end of the taking. During this time, the subject's eye E may move. For this reason, for example, when a tomographic image is captured with the B-scan direction set to a direction perpendicular to the strong principal axis 90 of the eye to be examined E, the axis mark M marked on one end moves from the time when the image is captured to the other end. The time difference until the time when the marked axis mark M is photographed increases, and the possibility that the subject's eye E moves during that time increases. If the subject's eye E moves while the two axis marks M are being photographed, the toric axis direction of the toric IOL cannot be accurately grasped. By photographing the two axis marks M at the same time or by reducing the time difference between the photographing of the two axis marks M, the subject's eye E moves until both the two axis marks M are photographed. can be suppressed, and the toric axis direction of the toric IOL can be accurately grasped.

Next, the computing device 60 detects the boundary between the tissue in the eye E to be examined and the toric IOL (S46). Since the anterior capsule, cortex, and nucleus are removed when the IOL is inserted, the anterior segment of the eye into which the IOL is inserted consists of the cornea, anterior chamber, IOL, and posterior capsule from anterior to posterior. Existing. As shown in FIG. 13, the arithmetic unit 60 detects a boundary L7 between the anterior chamber and the toric IOL (that is, the anterior surface of the toric IOL) and a boundary L8 between the toric IOL and the posterior capsule (that is, the posterior surface of the toric IOL). do. When the measurement light passes through the inserted toric IOL, it is partially reflected at each of the anterior and posterior surfaces of the toric IOL. The interference signal information includes reflected light components reflected at these boundaries L7 and L8. Therefore, in step S46, boundaries L7 and L8 between the tissue of the subject's eye E and the toric IOL are detected based on these signal components included in the interference signal information.

Next, the arithmetic device 60 extracts regions near the boundaries L7 and L8 detected in step S46 (S48). At this time, the range of the region is set in advance so that the surface of the toric IOL is included in the extracted region. Specifically, for each pixel of the boundary L7 detected in step S46, the arithmetic unit 60 extracts a range from a position on the front side by a predetermined length to a position on the rear side by a predetermined length. . This allows extraction of a region including the surface of the toric IOL. A region near the boundary L8 is similarly extracted. By setting the region to be extracted so as to include the surface of the toric IOL, the axis mark M marked on the surface of the toric IOL is included in the extracted region. In this embodiment, a region near the surface on the front side and a region near the surface on the rear side of the toric IOL are extracted, but the configuration is not limited to this. For example, in order to analyze the state of the entire toric IOL, a region between boundaries L7 and L8 detected in step S46 may be extracted. The region extracted in step S48 is configured so that it can be set in advance by the inspector, so that the region desired by the inspector can be extracted.

Next, the computing device 60 creates a front image (for example, an En-face image) for each area extracted in step S48 (S50). That is, an en-face image (see FIG. 14) composed only of the area near the surface on the front side of the toric IOL and an en-face image composed only of the area near the surface on the back side of the toric IOL were created. be. Note that the method of creating the En-face image is the same as the method used in step S18 described above, so detailed description thereof will be omitted. In step S50, an en-face image consisting only of the area near the front side surface of the toric IOL and an en-face image consisting only of the area near the back surface side of the toric IOL are created. Therefore, in each En-face image, portions other than the region (for example, tissues of the eye E to be examined (anterior chamber, posterior capsule, vitreous body, etc.) and portions other than the surface of the toric IOL) are not superimposed and displayed. . Therefore, the examiner can easily and accurately observe the surface of the toric IOL. Also, the axis mark M of the toric IOL is marked on either the anterior surface or the posterior surface. The axis mark M can be detected with higher accuracy by separately forming the region near the front surface of the toric IOL and the region near the rear surface of the toric IOL.

Next, the arithmetic device 60 analyzes the toric axis of the toric IOL (S52). As described above, the en-face image composed only of the area near the front surface side of the toric IOL created in step S50 and the en-face image composed only of the area near the back surface side of the toric IOL. , an axis mark M is displayed. The arithmetic device 60 detects the two axis marks M of the toric IOL from the En-face image created in step S50, and calculates the angle of the toric axis of the toric IOL inserted into the eye E to be examined. It should be noted that in either the En-face image created in step S50, which is composed only of the area near the front surface side of the toric IOL, or the En-face image composed only of the area near the back surface side of the toric IOL, If no axial mark M is detected, the position of the toric IOL haptics 94 (see FIG. 15) may be detected. Haptics 94 are the portions that protrude from the periphery of the IOL for securing the IOL. By detecting the position of haptics 94, the position of axis mark M can be predicted. Therefore, if the axis mark M cannot be detected from the front image created in step S50, the position of the haptics 94 is detected, and based on the position of the axis mark M predicted from the detected position of the haptics 94, , the angle of the toric axis of the toric IOL may be calculated. Further, the computing device 60 calculates the deviation amount (angle) of the toric axis of the toric IOL with respect to the strong principal radial line 90 of the eye E to be examined.

Finally, the computing device 60 outputs the analysis result to the touch panel 56 (S54). For example, FIG. 15 shows an example of the analysis result displayed on the touch panel 56. As shown in FIG. As shown in FIG. 15, the touch panel 56 displays an image in which the corneal shape map of the subject's eye E acquired in step S42 and the toric axis 92 of the toric IOL are superimposed and displayed. By superimposing the corneal shape map of the subject's eye E and the toric axis 92 of the toric IOL in this manner, the amount of angular deviation of the toric axis 92 of the toric IOL inserted into the subject's eye E can be easily evaluated. be able to.

In this embodiment, in step S44, the B scanning direction of the raster scanning method is set based on the corneal shape, but the present invention is not limited to such a configuration. For example, the B scan direction of the raster scan method may be set based on the astigmatic axis of the intermediate translucent body of the eye E to be examined. Specifically, the total refractive power of the eye E to be examined is calculated or obtained, and the astigmatic component of the total refractive power of the eye E to be examined is calculated. Then, the corneal astigmatism component is removed from the total refractive power of the eye E to be examined, and the astigmatic axis of the intermediate translucent body of the eye E to be examined is calculated. The computing device 60 sets the B-scanning direction of the raster scanning method so as to substantially coincide with the calculated astigmatic axis of the intermediate translucent body of the eye E to be inspected, and captures a tomographic image of the eye E to be inspected. In the subject's eye E into which the toric IOL has been inserted, the toric axis substantially coincides with the toric axis of the toric IOL when the corneal astigmatism component is removed from the total refractive power. That is, in the subject's eye E into which the toric IOL is inserted, the astigmatic axis of the intermediate translucent body and the toric axis substantially coincide. When the toric IOL is fixed in the subject's eye E in a state where the toric axis of the toric IOL deviates greatly from the strong principal axis of the cornea, the B scan direction is set parallel to the strong principal axis 90 of the subject's eye E. If it is set to the direction, the toric axis direction and the B scan direction are greatly deviated. By setting the B-scan direction based on the astigmatic axis of the intermediate translucent body, it is possible to scan in a direction substantially coinciding with the toric axis of the toric IOL. Therefore, even if the toric axis deviates from the corneal strong principal radius, the astigmatic toric axis direction of the toric IOL can be accurately grasped.

Although specific examples of the technology disclosed in this specification have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. In addition, the technical elements described in this specification or in the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

10: Light source 14: Interference optical system 20: Scanning-alignment optical system 24: Reference part 40: Balance detector 50: K-clock generator 52: First driving device 54: Second driving device 56: Touch panel 60: Arithmetic device 90: strong principal axis of eye to be examined 92: toric axis of toric IOL E: eye to be examined M: axis mark

Claims (6)

an imaging unit that captures a tomographic image of the anterior segment of the eye to be inspected;
and a computing unit,
The calculation unit is
a boundary detection process for detecting a boundary between tissues in a tomographic image of the anterior segment of the eye to be inspected captured by the imaging unit;
an extraction process for extracting a tissue defined by the boundary detected by the boundary detection process or a specific region set in the vicinity of the tissue from a tomographic image of the anterior segment of the eye to be inspected;
front image generation processing for generating a front image of the specific region using the image data of the specific region extracted by the extraction processing, and
the boundary detection processing detects a boundary between the inserted toric intraocular lens and the tissue of the eye to be examined in a tomographic image of the eye to be examined, into which the toric intraocular lens is inserted;
The extraction process extracts a specific region set near a boundary between the inserted toric intraocular lens and the tissue of the eye to be examined,
the specific region includes the surface of the toric intraocular lens;
The ophthalmologic apparatus , wherein the computing unit is configured to be capable of further executing a toric axis direction calculation process for calculating a toric axis direction of the toric intraocular lens based on the front image generated by the front image generation process . a display unit for displaying a tomographic image of the anterior segment of the subject's eye captured by the imaging unit;
a specific region setting unit operated by an examiner to set the specific region in the tomographic image displayed on the display unit;
2. The ophthalmologic apparatus according to claim 1, wherein said calculation unit generates a front image of said specific area set by said specific area setting unit. 3. The ophthalmology clinic according to claim 1, wherein said calculation unit is configured to be capable of further executing analysis processing for analyzing a state within said specific region based on the front image generated by said front image generation processing. Device. 4. The photographing unit according to any one of claims 1 to 3, wherein the photographing unit sets a scanning direction based on a corneal shape of the eye to be examined, and photographs a tomographic image of an anterior segment of the eye to be examined for use in the boundary detection processing. 10. An ophthalmic device according to claim 1 . The imaging unit captures a tomographic image of the anterior segment of the eye to be inspected by a raster scan method,
5. The ophthalmologic apparatus according to claim 4 , wherein the scanning direction of the raster scanning method is a direction substantially parallel to the strong principal axis of the cornea of the subject's eye. 6. The display unit according to claim 4 , further comprising a display unit that displays a corneal shape map indicating the corneal shape and an image indicating the toric axis direction of the toric intraocular lens calculated by the toric axis direction calculating process in an overlapping manner. ophthalmic equipment.

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