JP2024076492A - Ophthalmic Equipment - Google Patents

Abstract

[Problem] To obtain a more appropriate shape of anterior ocular tissue. [Solution] The present invention includes a cross-sectional imaging optical system that projects imaging light onto the anterior ocular segment of a test eye and receives return light from the anterior ocular segment of the test eye that has been optically cut by the imaging light to obtain a cross-sectional image of the anterior ocular segment of the test eye, a deviation detection means that detects deviation of the test eye, including the rotational direction of the test eye, when obtaining the cross-sectional image of the anterior ocular segment, relative to a predetermined alignment state between the test eye and the cross-sectional imaging optical system, and a processing means that performs image processing on the anterior ocular segment cross-sectional image obtained by the cross-sectional imaging optical system to obtain a predetermined shape of the anterior ocular tissue, and a processing means that corrects the obtained shape of the anterior ocular tissue based on the detection result of the deviation, including the rotational direction of the test eye, by the deviation detection means. [Selected Figure] Figure 2

Description

The present disclosure relates to an ophthalmic device that obtains the shape of the anterior segment tissue of a subject's eye.

As an ophthalmic device for obtaining the shape of the anterior segment of a test eye, for example, a device is known that projects a slit light onto the anterior segment of the test eye, obtains a cross-sectional image of the anterior segment using a Scheimpflug camera, and analyzes the shape of the anterior segment tissues such as the anterior and posterior surfaces of the cornea (see, for example, Patent Document 1). In addition, an optical coherence tomography (OCT) is sometimes used as a device for obtaining a cross-sectional image of the anterior segment.

JP 2012-249768 A

When acquiring an anterior segment cross-sectional image, if the position or orientation of the subject's eye deviates from the specified alignment state, it is necessary to correct the results of image processing of the anterior segment cross-sectional image in order to obtain the appropriate shape of the anterior segment tissue. However, in the past, only consideration was given to vertical deviation of the subject's eye, and no consideration was given to rotational (rotational) deviation of the subject's eye.

In view of the above-mentioned conventional techniques, the technical objective of the present disclosure is to provide an ophthalmic device capable of obtaining a more appropriate shape of anterior segment tissue.

The ophthalmic device provided by a typical embodiment of the present disclosure is characterized in that it includes a cross-sectional imaging optical system that projects imaging light onto the anterior segment of the test eye and receives return light from the anterior segment of the test eye that has been optically cut by the imaging light to obtain a cross-sectional image of the anterior segment of the test eye, a deviation detection means that detects a deviation of the test eye, including the rotational direction of the test eye, when the anterior segment cross-sectional image is obtained, relative to a predetermined alignment state between the test eye and the cross-sectional imaging optical system, and a processing means that performs image processing on the anterior segment cross-sectional image obtained by the cross-sectional imaging optical system to obtain a predetermined shape of the anterior segment tissue, and a processing means that corrects the shape of the anterior segment tissue obtained based on the detection result of the deviation, including the rotational direction of the test eye, by the deviation detection means.

FIG. 1 is an external view of an ophthalmologic apparatus. FIG. 2 is a schematic diagram showing an optical system of an ophthalmic apparatus. 1 is an example of a reference image of the front of the anterior segment. 11 is an example of a cross-sectional image of the anterior segment acquired at a certain scanning position in the Y direction. 11A and 11B are diagrams illustrating an example of a scanning position in the Y direction with respect to a subject's eye. 1 is an example of a height distribution map of the posterior corneal surface. 13 is an example of a front image acquired when no deviation of the subject's eye occurs. 11A and 11B are diagrams for explaining a method of detecting a deviation of the subject's eye in the Y direction and correcting the shape of corneal tissue. 11A and 11B are diagrams for explaining a method of detecting a deviation of the subject's eye in the X direction and correcting the shape of corneal tissue. 11A and 11B are diagrams for explaining a method of detecting a deviation of the subject's eye in a rotational direction and correcting the shape of corneal tissue.

[overview]
Hereinafter, one exemplary embodiment will be described with reference to the drawings. Note that the items grouped in <> below can be used independently or in conjunction with each other.

For example, an ophthalmic device (e.g., ophthalmic device 10) includes a cross-sectional imaging optical system (e.g., cross-sectional imaging optical system 300), a deviation detection means (e.g., control unit 50), and a processing means (e.g., control unit 50).

For example, the ophthalmic device may be equipped with a frontal imaging optical system (e.g., the frontal imaging optical system 200). For example, the frontal imaging optical system acquires a frontal image of the anterior part of the subject's eye. For example, the ophthalmic device may be equipped with an index projection optical system (e.g., the alignment index projection optical system 400). For example, the ophthalmic device may be equipped with a fixation target presenting optical system (e.g., the fixation target presenting optical system 150). For example, the ophthalmic device may be equipped with a scanning means (e.g., the alignment driving unit 13).

<Cross-section imaging optical system>
For example, the cross-sectional photographing optical system is an optical system for acquiring a cross-sectional image of the anterior segment of the subject's eye. For example, photographing light is projected onto the anterior segment of the subject's eye, and return light from the anterior segment of the subject's eye that is optically cut by the photographing light is received to capture a cross-sectional image of the anterior segment of the subject's eye. For example, the cross-sectional photographing optical system may include a light projecting optical system (e.g., the light projecting optical system 300a) that projects photographing light onto the anterior segment of the subject's eye, and a light receiving optical system (e.g., the light receiving optical system 300b) that captures a cross-sectional image of the anterior segment of the subject's eye. For example, the light projecting optical system may project slit light as the photographing light. In this case, the light receiving optical system may have a lens system (e.g., the lens system 322) and a photodetector (e.g., the image sensor 321) that are arranged in a Scheimpflug relationship with the light section caused by the slit light.

<Scanning Means>
For example, the scanning means scans the photographing light from the cross-section photographing optical system in a predetermined direction so that anterior-segment cross-sectional images are obtained at multiple sites of the anterior segment of the subject eye. For example, when the photographing light is slit light, the scanning means may raster scan the slit light. For example, raster scanning may be scanning the slit light in a direction perpendicular to the longitudinal direction of the slit light. In this case, the scanning means may scan the slit light by moving the cross-section photographing optical system in the scanning direction of the slit light. Alternatively, the scanning means may rotate and scan the slit light. In this case, the scanning means may scan the slit light by rotating the cross-section photographing optical system around the optical axis of the projection of the slit light.

<Displacement Detection Means>
For example, the deviation detection means detects deviation including at least the rotational direction of the test eye when the anterior ocular segment cross-sectional image is acquired with respect to a predetermined alignment state between the test eye and the cross-sectional photographing optical system. For example, the deviation detection means may detect deviation of the test eye based on a reference image of the front of the anterior ocular segment acquired in a predetermined alignment state between the test eye and the cross-sectional photographing optical system and the front image of the anterior ocular segment at the time of acquisition of the anterior ocular segment cross-sectional image. For example, the deviation detection means may detect deviation of the test eye based on positional changes between a feature point of the anterior ocular segment in the reference image and a feature point of the anterior ocular segment in the front image of the anterior ocular segment at the time of acquisition of the anterior ocular segment cross-sectional image.

For example, the deviation detection means may include a deviation direction discrimination means for discriminating whether the deviation of the subject's eye when acquiring the anterior eye cross-sectional image is a deviation in the rotational direction or a deviation in the planar direction. For example, the planar direction may be the up-down, left-right, and vertical directions (XY directions) of the subject's eye. The deviation of the subject's eye in the planar direction in the up-down, left-right, and vertical directions occurs when the subject's face moves in the up-down, left-right, and vertical directions while the line of sight of the subject's eye is parallel to the optical axis (e.g., optical axis L1) of the projection optical system of the imaging light. For example, when the imaging light of the cross-sectional imaging optical system is slit light, the planar direction may be a direction perpendicular to the longitudinal direction of the slit light and a direction along the longitudinal direction of the slit light. For example, the deviation of the subject's eye in the planar direction may include a tilt in the left-right direction of the subject's eye (in other words, the axis of the eye tilts) caused by the subject's face tilting in the left-right direction while the line of sight of the subject's eye is parallel to the optical axis of the projection optical system of the imaging light.

For example, the deviation detection means may process an anterior eye front image obtained by a front imaging optical system to detect the gaze direction of the subject's eye, and detect a deviation in the rotational direction of the subject's eye based on the detected gaze direction. For example, the deviation detection means may detect a feature point of the anterior eye in an anterior eye front image, and detect the gaze direction of the subject's eye based on a change in position of the detected feature point. Note that, for example, the pupil position or iris pattern may be used as the feature point of the anterior eye.

For example, the deviation detection means may detect whether the gaze direction of the test eye has changed based on a comparison of a first positional relationship between the pupil position (e.g., pupil center) and the corneal center of the test eye in a reference image of the front of the anterior eye, and a second positional relationship between the pupil position and the corneal center in the frontal image of the anterior eye at the time the anterior eye cross-sectional image is acquired.

For example, the deviation detection means may detect the deviation of the test eye in the planar direction based on a change in the positional relationship between a feature point of the anterior segment in a reference image of the front of the anterior segment and a feature point of the anterior segment in the front image of the anterior segment at the time of acquiring the anterior segment cross-sectional image. For example, the pupil position is typically used as the feature point of the anterior segment. For example, the iris pattern of the test eye may be used as the feature point of the anterior segment.

When the imaging light is scanned, the frontal image of the anterior eye when the anterior eye cross-sectional image is acquired can be the frontal image of the anterior eye acquired at each scanning position of the imaging light, and the deviation of the examined eye can be detected at each scanning position. For example, the pupil position can be detected using various methods such as the pupil center or the pupil edge.

For example, the corneal center of the test eye may be detected based on an index (e.g., a corneal reflection bright spot in a Purkinje image) projected onto the cornea of the test eye by an index projection optical system.

<Processing Means>
For example, the processing means performs image processing on the anterior ocular cross-sectional image acquired by the cross-sectional photographing optical system to acquire the shape of a predetermined anterior ocular tissue (e.g., corneal tissue). Then, for example, the processing means corrects the acquired shape of the anterior ocular tissue based on the detection result of the deviation of the subject eye, including the rotation direction, by the deviation detection means. This makes it possible to obtain a more appropriate shape of the anterior ocular tissue. For example, it is possible to obtain the corneal shape appropriately and with high accuracy. The anterior ocular tissue acquired by the processing means may include a crystalline lens.

For example, when the imaging light (e.g., slit light) is scanned by the scanning means, the processing means may perform image processing on the anterior segment cross-sectional images acquired at each scanning position of the imaging light to acquire the distribution shape of the anterior segment tissue (e.g., corneal tissue). For example, the processing means may acquire a map of at least one of the height distributions of the anterior corneal surface, the posterior corneal surface, and the corneal thickness as the distribution shape of the anterior segment tissue. Also, for example, the processing means may acquire the corneal radius of curvature as shape information of the anterior segment tissue.

For example, when the imaging light (e.g., slit light) is scanned by the scanning means, the processing means may correct the shape of the anterior eye tissue obtained for each scanning of the imaging light based on the detection result of the deviation of the test eye by the deviation detection means. This makes it possible to obtain a more accurate corneal tissue shape by correcting the anterior eye cross-sectional images obtained at each scanning position of the imaging light to the appropriate position without using the images at the incorrect position. In particular, when the imaging light is scanned, it takes time to scan the imaging light, and there is a high possibility that the test eye will move during this time. For this reason, it is effective to correct the anterior eye shape based on the detection of the deviation of the test eye.

For example, the processing means may change the correction method for the acquired shape of the anterior eye tissue based on the result of discrimination by the deviation detection means (e.g., deviation direction discrimination means) of whether the deviation is in the rotational direction or in the planar direction of the subject's eye. This allows the anterior eye shape to be corrected more appropriately according to the deviation in the rotational direction and the deviation in the planar direction of the subject's eye, and a more accurate corneal tissue shape can be obtained.

For example, if a deviation in the planar direction of the subject's eye is detected, the processing means may correct the shape of the anterior eye tissue by shifting the anterior eye cross-sectional image in the direction opposite to the deviation direction based on the detected deviation in the planar direction. For example, if a deviation in the rotational direction of the subject's eye is detected, the processing means may correct the shape of the anterior eye tissue by at least tilting the anterior eye cross-sectional image based on the detected rotation angle of the subject's eye. Furthermore, for example, the processing means may correct the shape of the anterior eye tissue by shifting the anterior eye cross-sectional image in the direction opposite to the rotation direction of the subject's eye based on the rotation angle of the subject's eye.

The processing means may acquire at least the shape of the cornea as the shape of the anterior segment tissue, and may perform correction processing of at least one of the corneal posterior surface shape and the corneal thickness if there is deviation of the subject's eye when acquiring the anterior segment cross-sectional image. This makes it possible to provide more accurate analysis information, particularly when calculating at least one of the corneal posterior surface shape and the corneal thickness.

[Example]
<Overall composition>
1 is an external view of an ophthalmic apparatus 10. For example, the ophthalmic apparatus 10 includes at least a measurement unit 11, a base 12, an alignment drive unit 13, a face support unit 15, a monitor 16, and a control unit 50.

The measurement unit 11 includes a measurement system and an imaging system used to examine the subject's eye. In this embodiment, the optical system shown in FIG. 2 is arranged. The alignment drive unit 13 changes the positional relationship of the measurement unit 11 with respect to the subject's eye. For example, the alignment drive unit 13 moves the measurement unit 11 three-dimensionally with respect to the base 12, thereby moving the measurement unit 11 in the X direction (left-right direction), Y direction (up-down direction), and Z direction (front-back direction) with respect to the subject's eye. The face support unit 15 is used to fix the subject's face in front of the measurement unit 11. The face support unit 15 is fixed to the base 12, and fixes the subject's eye by supporting the subject's face.

<Optical system>
2 is a schematic diagram showing the optical system of the ophthalmic apparatus 10. As an example, the ophthalmic apparatus 10 includes a cross-sectional imaging optical system 300, a fixation target presenting optical system 150, a front imaging optical system 200, and an alignment index projecting optical system 400. The ophthalmic apparatus 10 may additionally include a measurement optical system 100 and a Placido ring optical system 250. The ophthalmic apparatus 10 also includes half mirrors 501, 502, and 503 that branch and combine the optical paths of the optical systems, an objective lens 505, and the like.

<Measurement optical system>
For example, the measurement optical system 100 uses an optical system that objectively measures the ocular refractive power of the test eye E. For example, the values of the spherical power (S), cylindrical power (C), and astigmatism axis angle (A) of the test eye E are obtained as the measurement results of the ocular refractive power. For example, the measurement optical system 100 has a projection optical system 100a and a light receiving optical system 100b. For example, the projection optical system 100a has a measurement light source and projects a spot-shaped measurement light onto the fundus of the test eye E through the center of the pupil of the test eye E. The light receiving optical system 100b has an image sensor and extracts the reflected light beam of the measurement light beam reflected from the fundus in a ring shape through the peripheral part of the pupil and receives it on the image sensor. The ring image formed on the image sensor is analyzed to derive the ocular refractive power (each value of S, C, and A).

The light receiving optical system 100b may be equipped with a so-called Shack-Hartmann wavefront sensor. In this case, the wavefront aberration of the test eye is measured, and the distribution of eye refractive power at different positions in the pupil of the test eye is obtained.

<Fixation target presentation optical system>
The fixation target presenting optical system 150 presents a fixation target to the subject's eye E. The fixation target is presented on the optical axis of the objective lens 505. The fixation target presenting optical system 150 is used to fixate the subject's eye E.

For example, the fixation target presenting optical system 150 includes at least a light source 151 that emits visible light, and a fixation target plate 155. The fixation target plate 155 may be disposed at a position conjugate with the fundus. The fixation light beam from the light source 151 passes through the fixation target plate 155 and lens 156 on the optical axis L2, and then passes through the half mirror 503. It also passes through lens 504, passes through the half mirror 502, and is reflected by the half mirror 501, becoming coaxial with the optical axis L1. The fixation light beam further passes through the objective lens 505 to reach the fundus.

The fixation target plate 155 can be moved in the direction of the optical axis L2 by the drive unit 161, and the fixation target presenting optical system 150 is used to apply fogging and accommodative load to the subject's eye when the ocular refractive power is measured by the measurement optical system 100. When the ocular refractive power is measured, the drive unit 161 also moves the measurement light source of the projection optical system 100a, the image sensor of the light receiving optical system 100b, etc., together with the fixation target plate 155 in the direction of the optical axis.

<Frontal shooting optical system>
The front photographing optical system 200 is used to capture a front image of the anterior segment of the test eye E. For example, the front photographing optical system 200 includes an image sensor 205. The image sensor 205 may be disposed at a pupil conjugate position of the anterior segment of the test eye. As the front image, an observation image of the anterior segment may be acquired. In addition, the index image projected onto the cornea of the test eye by the alignment index projection optical system 400 is captured by the image sensor 205, and the observation image captured by the image sensor 205 is used for alignment, etc.

<Placido Ring Optical System>
The Placido ring optical system 250 is used to project a pattern index (e.g., a Placido ring pattern) onto the subject's eye. The Placido ring optical system 250 includes, for example, a light source 251, a light guide plate 252, and a Placido plate 253. The Placido plate 253 is disposed closer to the subject's eye than the objective lens 505. The Placido plate 53 has a plurality of Placido ring patterns formed on a light-transmitting plate. For example, the Placido plate 53 has a large number of black-painted light-shielding parts and unpainted light-transmitting parts 53b formed alternately in a concentric circle shape around the optical axis L1. The light guide plate 252 is disposed behind the Placido plate 253. The light guide plate 252 is formed of, for example, a plate of transparent resin such as acrylic resin. The light source 251 is disposed in a ring shape behind the light guide plate 252. The light source 251 is, for example, an LED that emits infrared light or visible light. Light emitted from a light source 251 is guided to a light guide plate 252 and illuminates a placido plate 253 from behind, so that a placido ring pattern is projected onto the cornea of the subject's eye.

The Placido ring pattern projected onto the cornea of the test eye is photographed by the frontal photographing optical system 200, and the photographed ring pattern image is subjected to image processing to analyze the shape distribution of the anterior corneal surface.

The placido ring optical system 250 may have an internal placido optical system. An opening is formed in the center of the placido plate 253 to allow the imaging light to pass through. This opening causes the placido ring pattern in the center to be missing. To compensate for this, the internal placido optical system is used to obtain a more detailed corneal shape. For example, the internal placido optical system is positioned behind the objective lens 505 (the side away from the subject's eye) so as to be coaxial with the optical axis L1. The internal placido optical system projects the placido ring pattern onto the subject's eye.

<Cross-section imaging optical system>
The cross-section photographing optical system 300 is used to photograph a cross-sectional image of the anterior segment of the eye. The cross-section photographing optical system 300 includes a light projecting optical system 300a and a light receiving optical system 300b.

The projection optical system 300a is coaxial with the projection optical axis (optical axis L1) of the measurement light in the measurement optical system 100, and projects slit light, which is an example of imaging light, onto the anterior segment. The projection optical system 300a has a light source 311 and a slit 312. The light source 311 may be an SLD light source, an LED light source, or other light source. In this embodiment, red visible light or near-infrared light having a peak wavelength between 650 nm and 800 nm is used as the imaging light. For example, the light source 311 emits light having a peak wavelength at 735 nm. The slit 312 may be located at a pupil conjugate position.

In this embodiment, the cross section through which the slit light passes in the anterior segment is called the "cutting surface." The cutting surface is the object surface of the cross-sectional imaging optical system. In this embodiment, the slit 312 is positioned so that the slit light is projected onto the anterior segment so as to optically cut the anterior segment in the horizontal direction (X direction). Therefore, in this embodiment, the horizontal plane (XZ cross section) including the optical axis L1 is set as the cutting surface. In this embodiment, the cutting surface is formed at least between the anterior surface of the cornea and the posterior surface of the crystalline lens.

The light receiving optical system 300b includes a lens system 322 and an image sensor 321, which is an example of a photodetector. In the light receiving optical system 300b, the lens system 322 and the image sensor 321 are arranged in a Scheimpflug relationship with a cutting surface set in the anterior eye. That is, the optical arrangement is such that the extension planes of the cutting surface, the main plane of the lens system 322, and the imaging surface of the image sensor 321 intersect at a single intersection line (single axis). The image sensor 321 receives return light (reflected light or scattered light) from the anterior eye segment that has been optically cut by the slit light. Then, a cross-sectional image of the anterior eye segment is acquired based on a signal from the image sensor 321.

In such a cross-sectional imaging optical system 300, the imaging light beam from the light source 311 becomes a slit light beam through the slit 312 on the optical axis L3, passes through the lens 313, and is reflected by the half mirror 503 to become coaxial with the optical axis L2. The imaging light beam also passes through the lens 504, passes through the half mirror 502, and is reflected by the half mirror 501 to become coaxial with the optical axis L1. The imaging light beam further passes through the objective lens 505 to reach the anterior eye. The return light from the cut surface formed in the anterior eye reaches the image sensor 321 through the lens 322. The lens system 322 is coated (wavelength selection filter) to cut the wavelengths of the light sources (light source 401, point light source 421, point light source 431) of the alignment target projection optical system 400 and transmit the wavelength of the imaging light of the light source 311. This prevents the alignment light from becoming noise when the anterior eye cross section is photographed.

<Alignment target projection optical system>
The alignment index projection optical system 400 is used to align (position) the measurement unit 11 (an optical system including the cross-sectional imaging optical system 300) with respect to the subject's eye E. The alignment index projection optical system 400 projects an alignment index onto the cornea of the subject's eye. The alignment index projection optical system 400 includes a first index projection optical system 400A and a second index projection optical system 400B.

The first target projection optical system 400A projects a target for aligning the measurement unit 11 in the XY direction with respect to the test eye. The first target projection optical system 400A includes a light source 401 that emits near-infrared light (for example, 900 to 1000 nm), a collimator lens 403, and a half mirror 405. The light emitted from the light source 401 is made into a substantially parallel beam by the collimator lens 403, and is reflected by the half mirror 405 to be coaxial with the optical axis L1, and is projected from the front direction of the test eye E. Then, a corneal reflection bright spot (target image) of the Purkinje image is formed at the center of the cornea by reflection from the cornea of the test eye. This corneal reflection bright spot is imaged by the image sensor 205 of the front imaging optical system 200, and the alignment state of the measurement unit 11 in the XY direction with respect to the test eye is detected based on the imaged corneal reflection bright spot.

The first index projection optical system 400A may be a ring-shaped light source arranged around the optical axis L1. In this case, a Mayer ring index is projected onto the cornea of the test eye, and the corneal center is detected based on the center of the Mayer ring image formed by reflection from the cornea of the test eye. The Mayer ring image may also be used to measure the shape of the anterior corneal surface. In the case of the Mayer ring image, the values of the corneal curvature, the degree of astigmatism, and the astigmatism axis angle in the area where the Mayer ring index is projected are obtained as the shape of the anterior corneal surface.

The second index projection optical system 400B projects an index for aligning the measurement unit 11 in the Z direction with respect to the subject's eye. The second index projection optical system 400B includes a point light source 421 for projecting an index at a finite distance, and a point light source 431 for projecting an index at infinity via a collimator lens. The point light source 421 and the point light source 431 emit infrared light (e.g., 900 to 1000 nm). The point light source 421 and the point light source 431 are respectively arranged symmetrically up and down and left and right with respect to the optical axis L1.

The index image by the second index projection optical system 400B is captured by the image sensor 205 of the front imaging optical system 200. Then, the control unit 50 moves the measurement unit 11 in the front-rear direction so that, for example, the interval between the index images (Purkinje images) by the symmetrical point light source 421 and the interval between the index images (Purkinje images) by the symmetrical point light source 431 are captured at a predetermined ratio, thereby performing alignment adjustment in the Z direction.

<Control system>
The control unit 50 controls the entire ophthalmic apparatus 10. The control unit 50 is connected to various electrical elements such as the image sensor 205, the image sensor 321, the image sensor of the measurement optical system 100, the light sources of the optical system, the monitor 16, the alignment drive unit 13, and the like. The control unit 50 also processes the anterior ocular cross-sectional image and other various examination results acquired by the measurement unit 11. The monitor 16 functions as a touch panel that also serves as an operation unit. The monitor 16 also displays the measurement results of the subject's eye E (anterior ocular cross-sectional image, corneal shape measurement results, etc.) on the screen. The control unit 50 is also connected to a memory 52, which is an example of a storage device. The memory 52 stores the front anterior ocular image acquired by the image sensor 205, the anterior ocular cross-sectional image acquired by the image sensor 321, the measurement results, and the like. The memory 52 also stores various control programs.

In this embodiment, the alignment drive unit 13 is used as a scanning means for scanning the slit light in a direction perpendicular to the longitudinal direction of the slit light so that anterior eye cross-sectional images can be obtained at multiple locations. That is, in this embodiment, the slit light from the projection optical system 300a is projected onto the anterior eye so as to optically cut the horizontal direction (X direction) of the subject's eye, so the alignment drive unit 13 scans the slit light by controlling the measurement unit 11 to move in the Y direction. Note that in a configuration in which the slit light is projected onto the anterior eye so as to optically cut the vertical direction (Y direction) of the subject's eye, the alignment drive unit 13 is controlled to move the measurement unit 11 in the X direction.

<Control operation>
The operation of the ophthalmologic apparatus 10 having the above-mentioned configuration will be described. In this embodiment, a case where a continuous measurement mode is set in which eye refractive power measurement, photographing of a Placido ring pattern image, and photographing of an anterior eye segment cross-sectional image are performed in sequence will be described. The measurement mode is set in advance on the setting screen of the monitor 16. Of course, each measurement and photographing can be set to be performed independently.

<Alignment>
First, the measurement unit 11 is aligned with the subject's eye E. The examiner instructs the subject to place his or her face on the face support unit 15. The control unit 50 starts presenting a fixation target and acquiring an anterior eye observation image.

For example, the control unit 50 controls the driving of the alignment drive unit 13 based at least on the front image of the anterior eye acquired through the front photographing optical system 200, and adjusts the subject's eye E and the ophthalmic device 10 to a predetermined positional relationship. More specifically, the control unit 50 processes the front image of the anterior eye acquired by the front photographing optical system 200, and detects the alignment state of the measurement unit 11 (optical axis L1) in the XY direction with respect to the corneal apex based on the index (corneal reflection bright spot) projected on the cornea of the subject's eye by the light source 401 of the first index projection optical system 400A. Then, the control unit 50 controls the driving of the alignment drive unit 13, and moves the measurement unit 11 in the XY direction so that the alignment state in the XY direction falls within a predetermined tolerance range. The control unit 50 also detects the alignment state in the Z direction (front-back direction) based on the interval between the index images by the second index projection optical system 400B. Then, the control unit 50 controls the driving of the alignment drive unit 13 to move the measurement unit 11 in the Z direction so that the alignment state in the Z direction falls within a predetermined tolerance range. The examiner may manually adjust the alignment of the measurement unit 11 with respect to the subject's eye E. For example, the examiner moves the measurement unit 11 by observing a front image of the anterior segment displayed on the monitor 16 and operating a switch displayed on the screen of the monitor 16. When the alignment is completed, the line of sight of the subject's eye and the optical axis L1 are approximately aligned and placed in a parallel positional relationship.

<Eye Refractive Index Measurement>
Once the alignment is complete, the ocular refractive power of the test eye E is measured by the measurement optical system 100. Measurement light from the projection optical system 100a is projected onto the fundus of the test eye E, and the measurement light beam reflected from the fundus is extracted in a ring shape via the periphery of the pupil, causing a ring image to be received by the image sensor of the light receiving optical system 100b. The control unit 50 obtains measurement results of the spherical power (S), cylindrical power (C), and astigmatic axis angle (A) of the test eye E by analyzing the captured ring image.

When measuring eye refractive power, a preliminary measurement is performed before the actual measurement. The fixation target plate 155 is moved to a conjugate position with respect to the fundus of the subject's eye E based on the spherical power of the preliminary measurement, and then the fixation target plate 155 is moved so as to add a cloud to the subject's eye E. The actual measurement is then performed with the subject's eye E being clouded.

<Photographing the Placido Ring Pattern Statue>
Next, the alignment state of the measurement unit 11 with respect to the subject's eye is confirmed, and an image of the Placido ring pattern is captured when the alignment is complete. The subject's eye is caused to fixate on the fixation target. The control unit 50 turns on the light source 251 of the Placido ring optical system 250, and the Placido ring pattern image projected onto the subject's eye's cornea is captured by the frontal imaging optical system 200. The Placido ring pattern image acquired by the imaging element 205 is stored in the memory 52. The control unit 50 performs image processing and analysis on the captured Placido ring pattern image to obtain a detailed shape map of the anterior corneal surface.

<Capturing cross-sectional images of the anterior eye segment>
Next, a cross-sectional image (Scheimpflug image) of the anterior segment of the subject's eye is captured. Here, a case will be described in which the slit light projected onto the anterior segment of the subject's eye by the light projection optical system 300a is scanned in the Y direction (a direction perpendicular to the longitudinal direction of the slit light). In this embodiment, the slit light scans by moving the measurement unit 11 in the Y direction by the alignment drive unit 13. During the slit light scan, the subject's eye is made to fixate on a fixation target presented by the fixation target presenting optical system 150.

First, when capturing a cross-sectional image, the alignment of the measurement unit 11 with respect to the subject's eye is completed (in this embodiment, the optical axis L1 is aligned with the corneal apex of the subject's eye), and a reference image ES of the front of the anterior eye is captured by the front imaging optical system 200 and stored in the memory 52. At this time, a cross-sectional image of the anterior eye using slit light in the alignment completed state may also be captured at the same time and stored in the memory 52.

Figure 3 is an example of a reference image ES of the front of the anterior eye. In the anterior eye front image, a corneal reflection bright spot (Purkinje image) appears, which is an index image by the light source 401 of the first index projection optical system 400A. This corneal reflection bright spot is image processed and detected as the corneal center KC. When alignment is complete, the corneal center KC coincides with the shooting center LO where the optical axis L1 is located. The corneal center KC detected here also coincides with the corneal apex. Note that if a Mayer ring is used for alignment, the center of the Mayer ring image may be detected as the corneal center KC.

In addition, the front image of the anterior eye is processed to detect the characteristic points of the subject's eye. For example, the pupil EP of the subject's eye in the front image of the anterior eye is processed to detect the pupil center PC. Note that the position of the pupil center PC of the subject's eye in the front image does not necessarily coincide with the position of the corneal center KC, but in the example of the reference image ES in FIG. 3, the position of the pupil center PC and the position of the corneal center KC are shown in a coincident state for ease of explanation. That is, in the example of FIG. 3, the pupil center PC and the corneal center KC are located at the shooting center LO (the intersection of the central axis Xo and the central axis Yo of the shooting image). Note that the index images of the point light source 421 and the point light source 431 of the second index projection optical system 400B also appear in the front image of the anterior eye, but are omitted from the example of FIG. 3.

The scanning of the slit light is performed, for example, by moving the position of the optical axis L1 of the measurement unit 11 in the Y direction from an upper position to a lower position of the subject's eye at a constant speed. Then, for example, cross-sectional images of the anterior segment by the slit light are acquired at predetermined time intervals (for example, 33 ms (0.033 seconds)) while the measurement unit 11 is moving downward. The acquired cross-sectional images of the anterior segment are associated with the scanning position in the Y direction and stored in the memory 52. In addition, at the same timing as the acquisition of each cross-sectional image, a frontal image of the anterior segment acquired by the frontal imaging optical system 200 is also stored in the memory 52.

Figure 4 shows an example of a cross-sectional image of the anterior segment acquired at a scanning position in the Y direction. The cross-sectional image of the anterior segment includes at least the anterior corneal surface KF and the posterior corneal surface KR. It also includes the crystalline lens.

Figure 5 is a diagram for explaining an example of scanning positions in the Y direction for the test eye. Figure 5(a) shows the state of a cut surface in the YZ direction of the cornea of the test eye, and Figure 5(b) shows a view of the test eye from the front. For example, as shown in Figure 5(a), assume that cross-sectional images CI1 to CI7 (CI1, CI2, CI3, CI4, CI5, CI6, CI7) corresponding to scanning positions H1 to H7 (H1, H2, H3, H4, H5, H6, H7) in the Y direction are obtained. Note that in Figure 5, for convenience of explanation, seven scanning positions are shown, but if the test eye is scanned in one second, for example, cross-sectional images at 30 scanning positions are obtained. Each scanning position in the Y direction can be obtained based on control information of the motor that moves the measurement unit 11 in the Y direction.

The control unit 50 performs image processing on each cross-sectional image CI1 to CI7 to determine the positions of the anterior corneal surface KF and the posterior corneal surface KR, which are examples of the shape distribution of the corneal tissue at each scanning position. Next, the control unit 50 acquires (creates) a map of the height distribution of at least one of the anterior corneal surface KF, the posterior corneal surface KR, and the corneal thickness by arranging the positions of the anterior corneal surface KF and the posterior corneal surface KR at each scanning position in correspondence with the scanning positions H1 to H7. The control unit 50 may also acquire the corneal radius of curvature as shape information of the anterior eye tissue.

The height distribution map between each scanning position for the anterior corneal surface KF and the posterior corneal surface KR can be obtained by interpolating so that each position is connected smoothly and continuously. A corneal thickness distribution map can be obtained from the distribution map of the anterior corneal surface KF and the distribution map of the posterior corneal surface KR. For example, the distribution maps of the anterior corneal surface KF, the posterior corneal surface KR, and the corneal thickness are represented as color-coded color maps, contour maps, etc., and displayed on the monitor 16. Figure 6 is an example of a height distribution map GK of the posterior corneal surface KR. The height distribution of the posterior corneal surface KR is represented as a color-coded color map. Similarly, a distribution map of the corneal thickness, etc. is also created and displayed on the monitor 16.

In addition, if a detailed shape distribution of the anterior corneal surface is obtained by capturing an image of the Placido ring pattern, the position of the anterior corneal surface KF obtained by cross-sectional photography can be matched to the position of the anterior corneal surface in the shape distribution, thereby creating a corneal thickness distribution map.

Here, when each cross-sectional image (CI1 to CI7) is obtained at each scanning position of the slit light, it takes, for example, 1 to 2 seconds, and the subject's eye may move during this time. Therefore, when the control unit 50 creates a shape distribution map of the corneal tissue based on the cross-sectional images corresponding to each scanning position, it detects the deviation (movement) of the subject's eye based on the reference image ES of the front image stored in the memory 52 and the front image acquired at each scanning position where the cross-sectional image was acquired. Then, when the control unit 50 detects the deviation of the subject's eye, when creating the shape distribution map of the corneal tissue, it corrects the shape distribution of the corneal tissue based on the detected deviation of the subject's eye. Note that the deviation of the subject's eye may not only be in the planar direction, but also in the rotational direction due to a change in the line of sight. Note that the planar direction is the left-right and up-down direction of the subject's eye (XY direction in this embodiment), in other words, the direction perpendicular to the longitudinal direction of the slit light and the direction along the longitudinal direction of the slit light.

<Detection of the presence or absence of deviation of the examined eye>
Regarding the deviation in the rotational direction of the subject's eye, the control unit 50 processes the front image obtained at each scanning position to detect a change in the gaze direction of the subject's eye. For example, the control unit 50 detects whether the gaze direction of the subject's eye has changed at each scanning position based on a comparison between a first positional relationship between the pupil position (e.g., pupil center PC) and the corneal center KC in the reference image ES of the front of the anterior eye and a second positional relationship between the pupil position and the corneal center KC in the front image of the anterior eye obtained at each scanning position (H1 to H7). In this embodiment, the pupil center PC is used as the pupil position. The pupil position can be detected by various methods, such as using the pupil center or the pupil edge.

In addition, with regard to the planar deviation of the subject's eye, for example, the control unit 50 detects the planar deviation of the subject's eye at each scanning position based on the positional relationship between the pupil position (feature point of the anterior eye) in the reference image ES of the front of the anterior eye and the pupil position (feature point of the anterior eye) in the front image of the anterior eye acquired at each scanning position (H1 to H7). Note that the pupil position is one of the feature points of the anterior eye, and the iris pattern may be used as a feature point of the anterior eye.

Figure 7 is an example of a front image EY3 acquired by the front imaging optical system 200 when there is no change in the line of sight of the test eye (i.e., no deviation in the rotational direction of the test eye) and no deviation in the planar direction during cross-sectional imaging at scanning position H3 in Figure 5. Note that on the left side of the front image EY3 in Figure 7, the state of the cut surface of the test eye's cornea in the YZ direction is shown as a reference diagram. In Figure 7, optical cutting of the anterior segment of the test eye by slit light is performed in the X direction at the position of the imaging center LO.

In this example of the front image EY3, the positional relationship between the pupil center PC and the corneal center KC is the same as the positional relationship between the pupil center PC and the corneal center KC in the reference image ES. Also, in the example of the front image EY3, the line of sight of the test eye and the optical axis L1 (the optical axis of the projection optical system 300a) are parallel. Therefore, the line of sight of the test eye when capturing a cross-sectional image at the scanning position H3 is detected as having not changed since the alignment was completed.

On the other hand, the pupil center PC of the front image EY3 is located a distance DY3 below the pupil center PC of the reference image ES (i.e., the shooting center LO) in the Y direction. If this distance DY3 is the expected distance at the scanning position H3, the subject's eye is detected as not deviated in the Y direction when cross-sectional imaging is performed at the scanning position H3. Note that the distance DY3 is obtained based on the positional relationship of the pupil center PC to the shooting center LO in the reference image ES and the position information of the scanning position H3. Furthermore, the pupil center PC of the front image EY3 is located in the same position as the reference image ES in the X direction, and the subject's eye is detected as not deviated in the X direction when cross-sectional imaging is performed at the scanning position H3.

<When there is deviation in the planar direction>
Regarding the planar deviation of the test eye, for example, the control unit 50 determines the planned pupil position at each scanning position based on a reference image ES of the front of the anterior eye, and detects the planar deviation (Y direction and X direction) of the test eye at each scanning position based on a comparison between this and the pupil position in the frontal image of the anterior eye acquired at each scanning position.

Figure 8 is a diagram explaining the detection of deviation of the test eye in the Y direction when acquiring an anterior segment cross-sectional image, and the method of correcting the shape of the corneal tissue. Figure 8(a) is an example of a front image EY3a acquired when the test eye is deviated upward in the Y direction by a deviation amount Δy during cross-sectional imaging at scanning position H3. Note that, on the left side of the front image EY3a, the state of the cut surface of the test eye's cornea in the YZ direction is shown as a reference diagram.

In the case of the front image EY3a, the positional relationship between the pupil center PC and the corneal center KC is the same as in the reference image EY3 (in the embodiment, the pupil center PC and the corneal center KC are in the same position), but the position of the pupil center PC relative to the shooting center LO in the Y direction is different from the distance DY3, and is a distance DY3a. Therefore, the deviation amount Δy is obtained by subtracting the distance DY3a from the distance DY3 (Δy = DY3 - DY3a).

Then, when the control unit 50 performs image processing on each cross-sectional image at each scanning position to create a shape distribution of the corneal tissue, as shown in FIG. 8(b), it places the cross-sectional image CI3 obtained at scanning position H3 at position H3a, which is shifted downward from scanning position H3 by the deviation amount Δy. This creates a shape distribution of the corneal tissue in which the deviation of the subject's eye in the Y direction has been corrected. In addition, by placing the cross-sectional image CI3 obtained at scanning position H3 at an appropriate position, rather than an inappropriate position, an appropriate shape distribution of the corneal tissue can be obtained.

Figure 9 is a diagram explaining the detection of deviation of the test eye in the X direction when acquiring an anterior eye cross-sectional image, and the method of correcting the shape of the corneal tissue. Figure 9 (a) is an example of a front image EY3b acquired when the test eye is deviated to the right in the X direction by a deviation amount Δx during cross-sectional imaging at scanning position H3. In this case, the positional relationship between the pupil center PC and the corneal center KC is the same as in the front image EY3 (in the embodiment, the pupil center PC and the corneal center KC are in the same position), but the position of the pupil center PC relative to the imaging center LO is shifted to the right in the X direction by the deviation amount Δx. Therefore, the deviation amount Δx can be obtained by calculating the distance of the pupil center PC from the imaging center LO in the X direction.

Then, when the control unit 50 performs image processing on each cross-sectional image at each scanning position to create a shape distribution of the corneal tissue, as shown in FIG. 9(b), it positions the cross-sectional image CI3 obtained at scanning position H3 at a position shifted by the deviation amount Δx in the opposite direction to the deviation direction of the test eye. This creates a shape distribution of the corneal tissue in which the deviation of the test eye in the X direction has been corrected.

When the subject's eye is deviated in both the Y direction and the X direction, the above-mentioned deviation amounts Δy and Δx may be obtained, respectively. Then, the cross-sectional image at the scanning position where the deviation was detected may be positioned at a position shifted based on the detected deviation amounts Δy and Δx.

<When there is deviation in the rotation direction>
Fig. 10 is a diagram for explaining a method of detecting deviation of the test eye in the rotational direction and correcting the corneal tissue shape. Fig. 10(a) shows a cut surface of the test eye cornea in the YZ direction when the test eye is rotated upward in the Y direction at an angle α. Fig. 10(b) is an example of a front image ER3 acquired when the test eye is deviated upward in the Y direction at an angle α during cross-sectional photography at the scanning position H3. The angle α is the angle of inclination of the line of sight LS with respect to the direction of the optical axis L1.

In the example of the front image ER3 in FIG. 10(b), the pupil center PC and the corneal center KC are not in the same position, but are separated by a distance DA in the Y direction. That is, while the pupil center PC and the corneal center KC were in the same positional relationship in the reference image ES, the positional relationship between the pupil center PC and the corneal center KC in the front image acquired at scanning position H3 has changed to a state in which they are separated by a distance DA in the Y direction. As a result, it is detected that the line of sight LS of the test eye is tilted in the Y direction from a parallel relationship with the optical axis L1, and a rotational deviation of the test eye has occurred.

In FIG. 10(a), if the corneal curvature radius is R, the anterior chamber depth distance is ACD, and the distance DA obtained from the front image is used as the movement amount of the pupil center PC, the rotation angle α, which is the deviation in the rotational direction of the test eye, can be obtained by the following formula.

sin α=DA/(R−ACD)
For example, the corneal curvature radius R can be obtained by processing a cross-sectional image of the anterior eye taken at the completion of alignment and calculating the shape of the anterior corneal surface. Alternatively, it may be obtained from the analysis results of the anterior corneal surface shape using the Placido ring pattern. The anterior chamber depth distance ACD is the distance from the corneal apex to the anterior surface of the crystalline lens, and is also obtained based on a cross-sectional image of the anterior eye taken at the completion of alignment. The above method of calculating the rotation angle α is one example, and various other calculation methods are possible.

When a rotational deviation of the subject's eye is detected, the control unit 50 corrects the corneal tissue shape in a manner different from that for the case of a planar deviation when creating the shape distribution of the corneal tissue. This is because, as shown in FIG. 10(a), the cross-sectional shape obtained at the scanning position H3 is a cross-sectional shape that is inclined at an angle α with respect to the original cross-sectional shape. When creating the shape distribution of the corneal tissue by image processing each cross-sectional image at each scanning position, the control unit 50 inclines the cross-sectional image CI3 obtained at the scanning position H3 by an angle α and places it at a position H3R shifted in the opposite direction to the rotational direction of the subject's eye, as shown in FIG. 10(c). The shift position H3R of the cross-sectional image CI3 can be obtained based on the angle α. For example, the shift position H3R can be mathematically obtained from the relationship in FIG. 10(a) based on the angle α, the distance DA, the scanning position H3, etc.

By carrying out the above-described correction process based on the detection of the rotational deviation of the subject's eye, a more accurate corneal tissue shape can be obtained without using the cross-sectional image CI3 obtained at scanning position H3 in an incorrect position.

The subject's eye fixates the fixation target even while the measurement unit 11 is moving to scan the slit light in the Y direction (or X direction). When the diopter of the subject's eye is 0D (diopter), the fixation target is placed at infinity in the eye refractive power measurement by the measurement optical system 10, so the gaze direction of the subject's eye does not change even while the measurement unit 11 is moving. On the other hand, when the diopter of the subject's eye is other than 0D, for example, the fixation target is placed near, so the gaze direction of the subject's eye that fixates on it may change as the measurement unit 11 is moved in the Y direction (or X direction). Even in this case, the position of the cross-sectional image acquired at each scanning position is corrected by detecting the deviation in the rotational direction of the subject's eye as described above, so that an appropriate corneal tissue shape can be obtained.

Note that in FIG. 10, an example is described in which the gaze direction LS of the test eye changes in the Y direction, but even when the gaze direction LS changes in the X direction, the deviation in the gaze direction and rotation of the test eye can be detected by a similar method. In the case of rotation in the X direction, the corneal tissue shape can be corrected by returning the cross-sectional image obtained at the scanning position by the detected rotation angle. In addition, when the gaze direction LS of the test eye changes in a combined manner in the Y and X directions, the corneal tissue shape can be corrected by combining correction in the Y direction and correction in the X direction.

As described above, when the shape of the anterior eye tissue (e.g., corneal tissue) is obtained by performing image processing on the anterior eye cross-sectional image, the shape of the anterior eye tissue is corrected based on the detection of the deviation of the subject eye, including the direction of rotation, so that a more appropriate shape of the anterior eye tissue can be obtained. In particular, by performing the above-described correction process when calculating at least one of the corneal posterior surface shape and the corneal thickness, more accurate analysis information of the corneal tissue shape can be provided.

<Example of transformation>
Although typical embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments shown here, and various modifications are possible.

For example, in the above embodiment, a case where imaging light (e.g., slit light) is scanned is described, but the correction of the anterior eye tissue shape based on the detection of the rotational and planar deviations of the subject's eye can also be applied when imaging light is not scanned.

In the above embodiment, the slit light is scanned in the planar direction of the Y or X direction by the cross-sectional imaging optical system 300, but the slit light may be scanned in the rotational direction by rotating the cross-sectional imaging optical system 300 around the optical axis of the slit light projection (optical axis L1). In this case, the light receiving optical system 300b may be configured to rotate around the optical axis L1 together with the light projection optical system 300a. Even when the slit light is scanned in the rotational direction, the calculation of the anterior eye tissue shape is corrected based on the detection of the deviation in the rotational direction and planar direction of the subject eye, using the same concept as described above.

The cross-sectional imaging optical system 300 projects slit light onto the subject's eye and uses an imaging system arranged in a Scheimpflug relationship, but is not limited to this. The cross-sectional imaging optical system 300 may be configured to obtain an anterior cross-sectional image, and may use, for example, an OCT optical system of an optical coherence tomography.

In the above description, a typical example of detecting deviation of the subject's eye is to capture a front image of the anterior eye using the front imaging optical system 200 that is coaxial with the optical axis L1 of the projection light of the cross-sectional imaging optical system 300, and to use a feature point of the anterior eye in the captured front image (e.g., pupil position), but this is not limited to the above. For example, the front imaging optical system 200 may be an optical system that captures the anterior eye of the subject's eye from two or more different directions and obtains two or more front images. In this case, the control unit 50 may process each front image captured from different directions to detect a feature point of the anterior eye (e.g., pupil position), detect the line of sight of the subject's eye based on the position change of the detected feature point of the anterior eye, and detect deviation of the subject's eye in the rotational direction based on this. In addition to the pupil, the iris pattern may be used to detect the feature point of the subject's eye.

In addition, in the above, the detection of the deviation in the planar direction of the subject's eye is exemplified by the translation in the XY direction, but the inclination of the subject's eye (the face tilts up and down in the left-right direction and the eye axis tilts) may also be included. For example, the control unit 50 detects common feature points of the anterior eye (e.g., iris pattern) in the reference image ES of the front anterior eye image and the front anterior eye image at the time of acquiring the cross-sectional image, and detects the eye inclination angle β (not shown) based on the change in the detected feature points. Alternatively, a face camera may be used to detect the inclination angle β. For example, the face camera is arranged in the ophthalmic device 10 so as to capture the subject's face including the subject's left and right eyes. The control unit 50 detects the eye inclination angle β by comparing the image captured by the face camera in a predetermined alignment state with the image captured by the face camera at the time of acquiring the cross-sectional image. Then, the control unit 50 corrects the acquired anterior eye tissue shape based on the inclination angle β. For example, the cross-sectional image can be corrected by tilting it by an angle β in the opposite direction to the detected tilt direction.

In the above, the corneal tissue shape is taken as an example of the shape of the anterior eye tissue acquired by the processing means (control unit 50), but since the anterior eye cross-sectional image captured by the cross-sectional imaging optical system 300 also includes the crystalline lens, the shape of the crystalline lens may also be acquired. In this case, too, the acquired crystalline lens shape is corrected based on the detection results of the deviation including the rotational direction of the subject's eye, using a concept similar to that of the correction of the corneal shape.

REFERENCE SIGNS LIST 10 Ophthalmic apparatus 13 Alignment driving unit 50 Control unit 52 Memory 150 Fixation target presenting optical system 200 Front photographing optical system 300 Cross-sectional photographing optical system 300a Light projecting optical system 300b Light receiving optical system 321 Image pickup element 400 Alignment target projecting optical system

Claims (5)

a cross-sectional photographing optical system that projects photographing light onto an anterior segment of the subject's eye and receives return light from the anterior segment of the subject's eye that has been optically cut by the photographing light to obtain a cross-sectional image of the anterior segment of the subject's eye;
a deviation detection means for detecting a deviation of the subject's eye, including a rotation direction of the subject's eye, when the anterior eye cross-sectional image is acquired, with respect to a predetermined alignment state between the subject's eye and the cross-section photographing optical system;
a processing means for performing image processing on the anterior ocular segment cross-sectional image acquired by the cross-section photographing optical system to acquire a predetermined shape of the anterior ocular segment tissue, the processing means correcting the acquired shape of the anterior ocular segment tissue based on a detection result of the deviation including the rotation direction of the subject's eye by the deviation detection means;
An ophthalmic apparatus comprising: 2. The ophthalmic apparatus of claim 1,
the deviation detection means includes a deviation direction discrimination means for discriminating whether a deviation of the subject's eye when the anterior eye cross-sectional image is acquired is a deviation in a rotational direction or a deviation in a planar direction,
The ophthalmologic apparatus according to claim 1, wherein the processing means changes a method of correcting the shape of the anterior eye tissue based on a result of the determination by the deviation direction determining means. 3. The ophthalmic apparatus according to claim 1,
a front photographing optical system for obtaining a front image of an anterior segment of a subject's eye;
an ophthalmic apparatus characterized in that the deviation detection means processes a front image of the anterior eye obtained by the front photographing optical system to detect a gaze direction of the test eye, and detects deviation of the test eye in the rotational direction based on the detected gaze direction. In the ophthalmic apparatus according to any one of claims 1 to 3,
a scanning means for scanning the imaging light so that the anterior ocular segment cross-sectional images are obtained at a plurality of sites of the anterior ocular segment of the subject eye;
The ophthalmologic apparatus according to claim 1, wherein the processing means corrects the shape of the anterior eye tissue to be acquired based on the detection result of the deviation by the deviation detection means for each scanning of the imaging light. In the ophthalmic apparatus according to any one of claims 1 to 4,
The ophthalmologic apparatus according to claim 1, wherein the processing means acquires at least a shape of the cornea as the shape of the anterior eye tissue, and processes at least one of a shape of the posterior corneal surface and a thickness of the cornea as the correction.