JP2024133180A - Ophthalmic Equipment - Google Patents

Abstract

[Problem] Acquiring information about a subject's eye in an appropriate alignment state. [Solution] An ophthalmic apparatus according to an embodiment includes an information acquisition unit that acquires information about the subject's eye by repeating corneal endothelial cell photography at a first time interval, an alignment unit that performs alignment, and a determination unit that determines whether the alignment is complete. When corneal endothelial cell photography is being repeatedly performed at the first time interval in parallel with the alignment, in response to the determination unit determining that the alignment is complete, the information acquisition unit performs corneal endothelial cell photography that interrupts the repetition of corneal endothelial cell photography at the first time interval at a timing different from the multiple photography timings at the first time interval, thereby acquiring multiple corneal endothelial cell images including corneal endothelial cell images obtained by the corneal endothelial cell photography repeatedly performed in parallel with the alignment and corneal endothelial cell images obtained by the interrupt corneal endothelial cell photography. [Selected Figure] Figure 4

Description

The present invention relates to an ophthalmic device.

Ophthalmic devices optically acquire information about the subject's eye, such as characteristics and images of the subject's eye. In many ophthalmic devices, the information about the subject's eye is acquired after the optical system is aligned with respect to the subject's eye. Alignment is performed, for example, by referring to the position of an image of a bright spot projected onto the subject's eye. Typically, alignment is performed in the left-right direction (X direction) and up-down direction (Y direction), as well as in the front-back direction (Z direction).

JP 2016-43143 A

When obtaining information about the subject's eye after alignment in this way, it is desirable to perform the examination after alignment is complete and before the subject's eye moves. In particular, in ophthalmic devices that require extremely high alignment precision, such as corneal endothelial cell imaging devices (specular microscopes), even a slight movement of the subject's eye can cause the device to enter an inappropriate alignment state.

The object of the present invention is to provide an ophthalmic device capable of acquiring information about a subject's eye in an appropriate alignment state.

The ophthalmic device according to the embodiment includes an information acquisition unit that acquires information about the test eye by repeatedly performing an examination of the test eye using an optical system at a first time interval, an alignment unit that aligns the optical system with the test eye, and a determination unit that determines whether the alignment is complete. When the information acquisition unit is repeatedly performing the examination at the first time interval in parallel with the alignment, and the determination unit determines that the alignment is complete, the information acquisition unit performs an examination that interrupts the repetition of the examination at the first time interval.

The ophthalmic apparatus according to the embodiment makes it possible to obtain information about the subject's eye in an appropriate alignment state.

1 is a schematic diagram illustrating an example of the configuration of an ophthalmologic apparatus according to an embodiment. 1 is a schematic diagram illustrating an example of the configuration of an ophthalmologic apparatus according to an embodiment. 5 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. 5A and 5B are schematic diagrams for explaining an example of the operation of the ophthalmologic apparatus according to the embodiment.

The ophthalmic device according to the embodiment has an alignment function that moves the optical system to a position suitable for examining the subject's eye, and generates information about the subject's eye by optically acquiring data on the subject's eye after alignment. The examination includes subjective examination and objective examination. Examples of subjective examination include distance vision examination, near vision examination, contrast examination, and glare examination. Objective examination includes objective measurement for measuring the characteristics of the subject's eye and photography for acquiring an image of the subject's eye. Examples of objective measurement include objective refraction measurement, corneal shape measurement, axial length measurement, and intraocular pressure measurement. Examples of photography include corneal endothelial cell photography, anterior segment photography, fundus photography (fundus camera, scanning laser ophthalmoscope, etc.), optical coherence tomography (OCT), etc.

The optical axis of the optical system of the ophthalmic device according to the embodiment may be inclined with respect to the front-to-back direction (Z direction). The direction and angle of this inclination may be arbitrary. Furthermore, the direction and angle of inclination may be fixed, or the direction and/or angle of inclination may be variable. In the latter case, a sensor and/or software for detecting the direction and/or angle of inclination may be provided, and the detected information may be used for control and calculation.

In the following embodiment, an ophthalmic device in which the optical axis of the optical system is tilted relative to the front-to-rear direction is described, but it is also possible to apply a configuration similar to the following embodiment to an ophthalmic device in which the optical axis of the optical system is arranged parallel to the front-to-rear direction.

<composition>
An example of the external configuration of an ophthalmic apparatus according to an embodiment is shown in Fig. 1. The ophthalmic apparatus 1 includes a base 2, a stand 3, a head unit 4, a face receiving unit 5, a joystick 8, and a display unit 10.

The platform 3 is mounted on the base 2. When the joystick 8 is operated, the platform 3 moves up and down, front and back, and left and right relative to the base 2. Typically, when the joystick 8 is rotated around its axis, the platform 3 moves up and down, and when the joystick 8 is tilted, the platform 3 moves forward and backward and left and right.

The head unit 4 houses various optical systems and mechanisms. The head unit 4 is mounted on the stand 3 and is moved up and down, forward and backward, and left and right relative to the stand 3 by an electric mechanism described below.

The face support unit 5 includes a chin rest 6 and a forehead rest 7 for fixing the subject's face. The joystick 8 is provided on the stand 3. The display unit 10 is provided on the back of the head unit 4 (the side facing the front side where the subject's eye is placed) and includes a touch panel. Various graphical user interfaces (GUIs) are displayed on this touch panel.

An external device 11 is connected to the ophthalmic device 1. The external device 11 may be any device, and the connection mode (communication form, etc.) between the ophthalmic device 1 and the external device 11 may also be any device. Examples of the external device 11 include a lens meter for measuring the optical characteristics of a lens, a reader/writer for a recording medium, a hospital information system (HIS) server, a DICOM server, a doctor's terminal, a mobile terminal, a server or terminal of the manufacturer of the ophthalmic device 1, a cloud server, etc.

An example of the internal configuration of the ophthalmic device 1 is shown in FIG. 2. The ophthalmic device 1 includes an optical unit 20, a Z alignment system 30, a movement mechanism 40, a data processing unit 50, a user interface 60, and a control unit 70.

(Optical unit 20)
The optical unit 20 includes, for example, various optical elements for measuring characteristics of the subject's eye E, various optical elements for photographing the subject's eye E, and a mechanism for moving some of the optical elements. The optical unit 20 is stored in the head unit 4. In this embodiment, the optical unit 20 includes an inspection optical system 21, an observation optical system 22, and an XY alignment system 23.

The XY alignment system 23 is provided in an optical path branched off from the optical path of the observation optical system 22 by a beam splitter 24 such as a half mirror. The optical path of the inspection optical system 21 and the optical path of the observation optical system 22 are combined by a beam splitter 25 such as a half mirror or a dichroic mirror, and this combined optical path OP is guided to the subject's eye E via an objective lens 26.

The axis of the composite optical path OP (the optical axis of the optical system) is inclined upward (+Y direction) at an angle θ with respect to the front-to-back direction (Z direction). Note that the inclination direction of the optical axis is not limited to upward, and may be any direction with respect to the Z direction (e.g. downward, left, right, etc.). Furthermore, the angle θ may be fixed or variable. If it is fixed, the value of the angle θ is arbitrary, and is set to 5 degrees, for example. If it is variable, the range of the angle θ is arbitrary. In this case, the inclination direction may also be arbitrarily variable.

Note that the optical path of the inspection optical system 21 and the optical path of the observation optical system 22 may not be combined. For example, when the ophthalmic device 1 has a function as a corneal endothelial cell imaging device (see, for example, the above-mentioned cited document), the inspection optical system 21 includes an illumination optical system and a photographing optical system whose optical axes are arranged in different directions, as well as an observation optical system whose optical axis is arranged in a different direction from the optical axes of both the illumination optical system and the photographing optical system. The optical axis of this observation optical system is typically arranged along the Z direction. Therefore, the optical axis of the inspection optical system 21 (the optical axis of the illumination optical system and the optical axis of the photographing optical system) is arranged in a different direction from the Z direction. In this way, there may be two or more optical axes of the inspection optical system 21. In that case, it is sufficient that at least one of the two or more optical axes is inclined with respect to the Z direction.

(Inspection optical system 21)
The examination optical system 21 is an optical system for acquiring information on the subject's eye E. The information acquired by the examination optical system 21 includes measurement data acquired by any ophthalmic measurement method and/or imaging data (image data, data collected to form image data, etc.) acquired by any ophthalmic imaging method (ophthalmic modality). The examination optical system 21 includes an optical system corresponding to the type of measurement and/or imaging that can be performed. The type of measurement and/or imaging that can be performed by the examination optical system 21 is not limited to one, and may be two or more. The examination optical system 21 may be configured to be able to perform any ophthalmic measurement and/or any ophthalmic imaging.

For example, the ophthalmic device 1 functions as one or more of the following devices: a corneal endothelial cell imaging device, an OCT device, a fundus camera, a slit lamp, an SLO, a refractometer, a keratometer, a tonometer, a perimeter, etc.

An example will be described. When the ophthalmic device 1 has the function of a corneal endothelial cell imaging device, the examination optical system 21 includes a corneal endothelial cell illumination optical system (slit light illumination optical system) and a corneal endothelial cell imaging optical system, similar to conventional corneal endothelial cell imaging devices (see, for example, the above-mentioned cited documents). The image acquired by the examination optical system 21 is sent to the data processing unit 50.

As another example, when the ophthalmic device 1 has a function as an OCT device, the examination optical system 21 includes the following components, similar to a general OCT device: a light source (low coherence light source, wavelength swept light source, etc.); an interference optical system that splits the light output from the light source into measurement light and reference light and causes the return light of the measurement light from the subject's eye E to interfere with the reference light; and a detection unit (spectroscope, balanced photodetector, etc.) that detects the interference light generated by the interference optical system. The data collected by the examination optical system 21 is sent to the data processing unit 50.

The examination optical system 21 may be provided with a configuration for providing functions associated with the examination. For example, a fixation optical system may be provided for projecting a visual target (fixation target) for fixating the subject's eye E onto the fundus Ef.

(Observation optical system 22)
The observation optical system 22 captures video (and still images) of the subject's eye E. The observation optical system 22 includes various lenses (imaging lenses, focusing lenses, relay lenses, etc.) and optical elements other than lenses (apertures, imaging elements (CCD image sensors, CMOS image sensors, etc.)). The observation optical system 22 may also include a light source. This light source emits, for example, infrared light (near-infrared light) and/or visible light. In this embodiment, infrared light is used to capture video of the anterior segment.

The observation optical system 22 may be configured to include two or more cameras. For example, two cameras are provided at different positions on the front surface (the surface facing the subject) of the optical unit 20. The two cameras are then used to photograph the anterior segment from different directions. In other words, the two cameras perform stereo photography of the anterior segment. The ophthalmic device 1 is capable of determining position information of the anterior segment based on two images acquired by the two cameras substantially simultaneously.

(XY alignment system 23)
The XY alignment system 23 irradiates the test eye E with light (infrared light) to perform alignment in directions perpendicular to the optical axis of the combined optical path OP of the inspection optical system 21 and the observation optical system 22 (left-right direction (X direction) and up-down direction (Y direction)).

The XY alignment system 23 includes a light source (infrared light source) provided in an optical path branched off from the optical path of the observation optical system 22 by the beam splitter 24. The light output from this light source is reflected by the beam splitters 24 and 25, passes through the objective lens 26, and is irradiated onto the subject's eye E. The light reflected by the cornea Ec passes through the objective lens 26, is reflected by the beam splitter 25, passes through the beam splitter 24, and is detected by the image sensor of the observation optical system 22.

The image of the reflected light detected in this manner (bright spot image) is depicted in the anterior eye image obtained by the observation optical system 22 and is used as an index for performing XY alignment (XY alignment index, second index). The control unit 70 can display the anterior eye image including the XY alignment index on the display unit 61 (display unit 10, etc.). At this time, the control unit 70 can superimpose an image (alignment mark) indicating the acceptable range of alignment deviation on the anterior eye image.

When performing manual XY alignment, the user moves the head unit 4 (optical unit 20) so as to guide the XY alignment index into the alignment mark.

When performing automatic alignment, the data processing unit 50 calculates the displacement of the XY alignment index relative to the alignment mark. Furthermore, the control unit 70 controls the movement of the head unit 4 (optical unit 20) in the XY directions so that the displacement calculated by the data processing unit 50 is cancelled.

Instead of detecting the XY alignment index using the observation optical system 22, it is also possible to detect the XY alignment index using, for example, a dedicated photodetector (such as a PSD sensor).

(Z alignment system 30)
The Z alignment system 30 moves integrally with the optical unit 20. The Z alignment system 30 irradiates the subject's eye E with light for performing alignment in the front-back direction (Z direction) with respect to the subject's eye E, and detects the return light. Light output from a Z alignment light source (infrared light source) 31 is irradiated onto the cornea Ec, reflected by the cornea Ec, and imaged on a line sensor 33 by an imaging lens 32.

When the relative position between the subject's eye E and the optical unit 20 changes in the Z direction, the projection position of the light onto the line sensor 33 changes. The projected image onto the line sensor 33 is used as an index for performing Z alignment (Z alignment index, first index). The data processing unit 50 calculates the displacement in the Z direction of the corneal apex, corneal endothelium, etc. of the subject's eye E based on the projection position of the Z alignment index onto the line sensor 33. The control unit 70 controls the movement of the head unit 4 in the Z direction so that the calculated displacement is cancelled.

Note that in conventional technology, movement in the Z direction and movement in the XY directions according to the tilt angle θ are alternated, but in this embodiment, the head unit 4 is moved in a direction according to the tilt angle θ (the direction of the optical axis of the inspection optical system 21).

(Moving mechanism 40)
The moving mechanism 40 is a mechanism for moving the optical unit 20 (the head section 4). The moving mechanism 40 can move the optical unit 20 three-dimensionally. The moving mechanism 40 includes a mechanism for electrically moving the optical unit 20 (for example, a mechanism for moving the head section 4 relative to the mount 3). In addition to or instead of such an electric mechanism, the moving mechanism 40 may include a mechanism for manually moving the optical unit 20 (for example, a mechanism for moving the mount 3 relative to the base 2).

The movement mechanism 40 may be provided with a left-right movement mechanism 40X for moving the optical unit 20 in the left-right direction (X direction), a vertical movement mechanism 40Y for moving the optical unit 20 in the up-down direction (Y direction), and a front-rear movement mechanism 40Z for moving the optical unit 20 in the front-rear direction (Z direction).

Each of the left-right movement mechanism 40X, the up-down movement mechanism 40Y, and the front-back movement mechanism 40Z is equipped with an actuator. The actuator includes, for example, a pulse motor. The actuator generates a driving force under the control of the control unit 70. The movement mechanism 40 includes a transmission mechanism for transmitting the driving force output by the actuator to move the optical unit 20.

The control unit 70 controls at least one of the three actuators according to a predefined computer program. The control unit 70 also controls at least one of the three actuators based on an operation signal input from the operation unit 62 of the user interface 60.

(Data Processing Unit 50)
The data processing unit 50 processes information acquired by the ophthalmologic apparatus 1 and information input from the outside. For example, the data processing unit 50 executes processing related to alignment. In this embodiment, a first control amount calculation unit 51 and a second control amount calculation unit 52 are provided as elements for executing Z alignment. Furthermore, the data processing unit 50 executes known processing for XY alignment.

The data processing unit 50 also performs various data processing operations, such as processing data acquired by the inspection optical system 21 and processing images acquired by the observation optical system 22. The data processing unit 50 includes a processor, a storage device, software (computer program), and the like for performing such processing.

(First Control Amount Calculation Unit 51)
The first control amount calculation unit 51 calculates the control amount of the forward/backward movement mechanism 40Z based on the Z alignment index. The control amount may be any amount that can be used to control the movement mechanism 40. For example, if the actuator included in the movement mechanism 40 is a pulse motor, the number of pulses sent to the pulse motor (pulse count) may be used as the control amount. Alternatively, the distance by which the optical unit 20 is moved may be used as the control amount.

In this embodiment, the projected image of the Z alignment system 30 onto the line sensor 33 is used as the Z alignment index. The first control amount calculation unit 51 determines the position of the test eye E (corneal apex, corneal endothelium, etc.) in the Z direction based on the projected position of the Z alignment index onto the line sensor 33.

Here, the position in the row of light detection elements included in the line sensor 33 (address of the light detection element) is previously associated with a position in the Z direction. Based on the output signal from the line sensor 33, the first control amount calculation unit 51 identifies the projection position of the Z alignment index, that is, the address of the element that detects the reflected light from the subject's eye E. Then, the position in the Z direction corresponding to the identified address is obtained. This processing related to Z alignment is the same as in the conventional method.

(Second Control Amount Calculation Unit 52)
The second control amount calculation unit 52 calculates at least one of the control amount (X control amount) of the left/right movement mechanism 40X and the control amount (Y control amount) of the up/down movement mechanism 40Y based on the control amount (Z control amount) calculated by the first control amount calculation unit 51.

The control amount calculated by the second control amount calculation unit 52 is a control amount according to the direction of inclination of the optical axis of the inspection optical system 21 relative to the Z direction. In this embodiment, as shown in FIG. 2, the optical axis of the composite optical path OP is inclined in the Y direction, so the Y control amount is calculated. Below, an example of processing for calculating the Y control amount (and/or the X control amount) from the Z control amount calculated by the first control amount calculation unit 51 is described.

As a first example of a process for determining a Y control amount from a Z control amount, correspondence information created in advance can be referenced. The correspondence information is stored in advance in, for example, the control unit 70 or the data processing unit 50. Alternatively, the correspondence information may be stored in advance in the external device 11 and referenced. The element (storage unit) in which the correspondence information is stored may include, for example, any of a semiconductor memory, a magnetic storage device, an optical storage device, and a magneto-optical disk.

The correspondence information is, for example, table information in which a Y control amount is associated with each of a plurality of values of the Z control amount. In such table information, for example, the values of the Z control amount 0, ΔZ ₁ , ΔZ ₂ , ΔZ ₃ , ..., ΔZ _N-1 , ΔZ _N are associated with the values of the Y control amount 0, ΔY ₁ , ΔY ₂ , ΔY ₃ , ..., ΔY _N-1 , ΔY _N (ΔZ _n < ΔZ _n+1 , ΔY _n < ΔY _n+1 ). Here, the relationship between ΔZ _n and ΔY _n is determined based on the inclination angle θ of the optical axis of the inspection optical system 21 (the optical axis of the composite optical path OP) with respect to the Z direction. Specifically, ΔY _n for ΔZ _n is calculated by the relational expression ΔY _n = ΔZ _n × tan θ (n = 1, 2, ..., N).

The correspondence information is not limited to discrete information such as the table information described above. For example, a graph that continuously represents the relationship between the Z control amount value and the Y control amount value can be used as the correspondence information. This is, for example, a graph with the Z control amount value ΔZ on the horizontal axis and the Y control amount value ΔY on the vertical axis. Such a graph can be obtained by the relational equation ΔY = ΔZ × tan θ.

When the tilt angle θ is variable, correspondence information can be prepared for each of a plurality of values (discrete values) θ ₁ , θ ₂ , ..., θ _K of the tilt angle θ. For example, table information can be created in which the Z control amount value ΔZ _n (θ _k ) is associated with the Y control amount value ΔY _n (θ _k ) for each tilt angle θ = θ _k (k = 1, 2, ..., K). Here, the Z control amount value ΔZ _n (θ _k ) and the Y control amount value ΔY _n (θ _k ) satisfy the relational expression ΔY _n (θ _k ) = ΔZ _n (θ _k ) × tan θ _k . In addition, by using a similar relational expression, a graph can be created for each tilt angle θ = θ _k (k = 1, 2, ..., K).

Alternatively, it is also possible to prepare correspondence information that takes into account continuous changes in the tilt angle θ. For example, for the tilt angle θ, which is a continuous variable, table information can be created in which the Z control amount value ΔZ _n (θ) is associated with the Y control amount value ΔY _n (θ). Here, the Z control amount value ΔZ _n (θ) and the Y control amount value ΔY _n (θ) satisfy the relational expression ΔY _n (θ) = ΔZ _n (θ) × tan θ. Furthermore, by using a similar relational expression, it is also possible to create correspondence information as a family of functions with the tilt angle θ, which is a continuous variable, as an index.

The correspondence information is not limited to table information or graphs. In addition, correspondence information in which an X control amount is associated with a Z control amount can be created in the same manner as correspondence information in which a Y control amount is associated with a Z control amount.

The second control amount calculation unit 52 can calculate the Y control amount (and/or the X control amount) based on the Z control amount calculated by the first control amount calculation unit 51 and the corresponding information.

When the corresponding information is table information, the second control amount calculation unit 52 first selects the value of the Z control amount in the table information corresponding to the Z control amount calculated by the first control amount calculation unit 51. In the table information, the values of the Z control amount are discrete. When a value equal to the Z control amount calculated by the first control amount calculation unit 51 is included in the table information, this value is selected. The selected value is adopted as the Y control amount.

If the table information does not include a value equal to the Z control amount calculated by the first control amount calculation unit 51, the second control amount calculation unit 52 selects, for example, a value closest to the Z control amount calculated by the first control amount calculation unit 51. Alternatively, it is also possible to select the largest value among values smaller than the Z control amount calculated by the first control amount calculation unit 51, or to select the smallest value among values larger than the Z control amount calculated by the first control amount calculation unit 51. The selected value is adopted as the Y control amount corresponding to the Z control amount calculated by the first control amount calculation unit 51.

When the correspondence information is a (continuous) graph, the second control amount calculation unit 52 identifies a coordinate on the coordinate axis (e.g., horizontal axis) of the Z control amount corresponding to the Z control amount calculated by the first control amount calculation unit 51, and identifies a coordinate on the coordinate axis (e.g., vertical axis) of the Y control amount associated with the coordinate by the graph. The value indicated by the identified coordinate is adopted as the Y control amount corresponding to the Z control amount calculated by the first control amount calculation unit 51.

A second example of the process for calculating the Y control amount from the Z control amount will be described. In this example, when the Z control amount is calculated by the first control amount calculation unit 51, the second control amount calculation unit 52 calculates the Y control amount (and/or the X control amount) corresponding to this Z control amount based on the tilt angle θ of the optical axis of the inspection optical system 21. In other words, in this example, the Y control amount (and/or the X control amount) corresponding to the Z control amount is calculated each time.

Specifically, the second control amount calculation unit 52 uses trigonometry to calculate the Y control amount (and/or the X control amount) based on the Z control amount and the tilt angle θ calculated by the first control amount calculation unit 51. Here, as in the first example, the trigonometric relational equation "(Y control amount) = (Z control amount) × tan θ" can be used. In this example, such a relational equation is stored in advance in the control unit 70, the data processing unit 50, the external device 11, etc.

(Examined eye information generation unit 53)
The subject's eye information generating unit 53 acquires subject's eye information based on data acquired by the optical unit 20 (e.g., the examination optical system 21). The type of acquired subject's eye information corresponds to the function of the ophthalmologic apparatus 1. do.

As an example, when a corneal endothelial cell image is obtained by the optical unit 20, that is, when the ophthalmic device 1 functions as a corneal endothelial cell imaging device, any known technology in the field, including the above-mentioned cited documents, can be used. Typically, the subject's eye information generating unit 53 can execute the following processes: correction of the corneal endothelial cell image (contrast correction, brightness correction, sharpening, etc.); processing for selecting the optimal image from multiple images acquired in succession; processing for generating a panoramic image from images of different regions; processing for analyzing images to determine the density of corneal endothelial cells; processing for generating an image showing the contours of corneal endothelial cells.

As another example, when OCT data is collected by the optical unit 20, that is, when the ophthalmic device 1 functions as an OCT device, any known technology in the field can be used. Typically, the subject eye information generating unit 53 forms a tomographic image based on the collected OCT data. For example, the subject eye information generating unit 53 performs signal processing on the spectral distribution based on the sampling result for each A-line to form a reflection intensity profile for each A-line, as in the conventional swept-source OCT, and images and arranges these A-line profiles along the scan line. The above signal processing includes noise removal (noise reduction), filter processing, FFT (Fast Fourier Transform), and the like. The subject eye information generating unit 53 may also perform image processing and analysis processing on the tomographic image. For example, the subject eye information generating unit 53 may be configured to perform creation of three-dimensional image data (stack data, volume data, etc.) based on raster scan data, rendering of the three-dimensional image data, image correction, image analysis based on an analysis application, and the like.

(User Interface 60)
The user interface 60 includes a display unit 61 and an operation unit 62. The display unit 61 includes the display unit 10, and operates under the control of the control unit 70. The operation unit 62 is used to operate the ophthalmic apparatus 1 and input information. The display unit 61 and the operation unit 62 do not need to be configured as separate devices. For example, it is possible to use a device in which a display function and an operation function are integrated, such as a touch panel.

(Control unit 70)
The control unit 70 includes a processor, a storage device, a communication interface, software, etc. The control unit 70 performs various controls in the ophthalmologic apparatus 1. For example, the control unit 70 executes control of the inspection optical system 21, control of the observation optical system 22, control of the XY alignment system 23, control of the Z alignment system 30, control of the movement mechanism 40 (individual control and/or coordinated control of the left-right movement mechanism 40X, the up-down movement mechanism 40Y, and the front-back movement mechanism 40Z, etc.), control of the data processing unit 50, control of the display unit 61, etc. The control unit 70 includes an alignment control unit 71, a determination unit 72, and an inspection control unit 73.

(Alignment control unit 71)
The alignment control unit 71 executes control for XY alignment and Z alignment. In XY alignment, the alignment control unit 71 causes the XY alignment system 23 to generate an XY alignment index. The data processing unit 50 calculates the displacement of the XY alignment index (for example, an image of the XY alignment index depicted in the anterior eye image obtained by the observation optical system 20) relative to the alignment mark. The alignment control unit 71 executes movement control of the head unit 4 (optical unit 20) in the XY directions so that the displacement calculated by the data processing unit 50 is canceled. Such displacement calculation and movement control are repeatedly executed at time intervals according to the frame rate of the anterior eye image.

In Z alignment, the alignment control unit 71 causes the Z alignment system 30 to generate a Z alignment index. Furthermore, the alignment control unit 71 controls the movement mechanism 40 to move the optical unit 20 along the optical axis of the composite optical path OP based on the Z alignment index (e.g., a projected image onto the line sensor 33). In this embodiment, the alignment control unit 71 controls the front-rear movement mechanism 40Z based on the Z control amount acquired by the first control amount calculation unit 51 and the up-down movement mechanism 40Y (and/or the left-right movement mechanism 40X) based on the Y control amount (and/or the X control amount) acquired by the second control amount calculation unit 52 in parallel, thereby realizing the movement of the optical unit 20 along the optical axis of the composite optical path OP.

In such Z alignment, the alignment control unit 71 can substantially match the start timing of control of the forward/backward movement mechanism 40Z based on the Z control amount with the start timing of control of the up/down movement mechanism 40Y (and/or left/right movement mechanism 40X) based on the Y control amount (and/or X control amount). Furthermore, the alignment control unit 71 can substantially match the end timing of control of the forward/backward movement mechanism 40Z based on the Z control amount with the end timing of control of the up/down movement mechanism 40Y (and/or left/right movement mechanism 40X) based on the Y control amount (and/or X control amount).

Such coordinated control is realized by adjusting the movement speed in the forward/backward direction (Z direction) and the movement speed in the up/down direction (or left/right direction, or a movement direction including both up/down and left/right components). For example, if the movement distance in the Z direction is _DZ , the movement distance in the Y direction is _DY , and the movement speed in the Z direction is _VZ , then the movement speed in the Y direction _VY can be set by the following formula: _VY = _VZ × ( _DY / _DZ ).

(Determination unit 72)
The determination unit 72 determines whether the alignment is complete. In a typical example of XY alignment, the data processing unit 50 calculates the displacement of the XY alignment index relative to the alignment mark. The determination unit 72 compares the amount of this displacement with a predefined threshold. If the amount of displacement exceeds the threshold, it is determined that the XY alignment is not complete, and the XY alignment is continued. If the amount of displacement is equal to or less than the threshold, it is determined that the XY alignment is complete. That is, the XY alignment is performed so that the amount of displacement of the XY alignment index relative to the alignment mark is equal to or less than the threshold.

In Z alignment, the position of the Z alignment index in the line sensor 33 (the position of the photodetection element that contributed to the generation of the Z alignment index among the photodetection element row included in the line sensor 33) is referenced. The determination unit 72 can determine whether or not Z alignment is complete based on the displacement relative to the position of the line sensor 33 that corresponds to a proper Z alignment state (for example, the photodetection element located at the center of the photodetection element row), that is, the position (address) of the photodetection element that contributed to the formation of the Z alignment index. Alternatively, the Z control amount calculated by the first control amount calculation unit 51 can be compared with a default threshold value, and it can be determined that Z alignment is complete when the Z control amount is equal to or less than the threshold value.

In a typical example, Z alignment is performed after XY alignment. In this case, in response to the determination unit 72 determining that XY alignment has been completed, the alignment control unit 71 ends control for XY alignment and starts control for Z alignment. Furthermore, in response to the determination unit 72 determining that Z alignment has been completed, the alignment control unit 71 ends Z alignment, and the inspection control unit 73 described below starts inspection.

(Test control unit 73)
The examination control unit 73 receives the determination result that the alignment is completed from the determination unit 72, and controls the examination optical system 21 to acquire data of the subject's eye E. In a typical example, the examination control unit 73 causes the examination optical system 21 to start acquiring data upon completion of the Z alignment.

The processor refers to a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or a programmable logic device (e.g., an SPLD (Simple Programmable Logic Device), a CPLD (Complex Programmable Logic Device), or an FPGA (Field Programmable Gate Array)). The processor realizes the functions according to the embodiment by, for example, reading and executing a computer program stored in a memory circuit or a memory device.

Actions
A description will now be given of the operation of the ophthalmic apparatus 1. An example of the operation of the ophthalmic apparatus 1 is shown in FIG.

(S1: Start photographing the anterior segment)
First, the control unit 70 starts photographing the anterior eye segment by controlling the observation optical system 22. Frames sequentially output from the observation optical system 22 are sent to the data processing unit 50 via the control unit 70. In parallel with this, the control unit 70 can cause the display unit 61 to display a moving image of the anterior eye segment.

(S2: Start generating alignment indices)
Next, the alignment control unit 71 controls the XY alignment system 23 and the Z alignment system 30 to generate an XY alignment index and a Z alignment index. The light output from the XY alignment system 23 is reflected by the cornea Ec and is depicted as a bright point image in the frame of the anterior eye image. The control unit 70 sequentially transfers the frame of the anterior eye image to the data processing unit 50.

The light output from the Z alignment light source 31 is reflected by the cornea Ec and projected onto the line sensor 33 by the imaging lens 32. The line sensor 33 inputs a detection signal to the control unit 70 at a predetermined time interval. The control unit 70 sequentially transfers this detection signal to the data processing unit 50.

In this example, Z alignment is performed after XY alignment. Therefore, only XY alignment indices may be generated during XY alignment, and only Z alignment indices may be generated during Z alignment.

(S3: Perform XY alignment)
The alignment control unit 71, the data processing unit 50, and the movement mechanism 40 perform XY alignment based on the XY alignment index whose generation has started in step S2. That is, the data processing unit 50 determines the deviation in the XY directions by referring to the XY alignment index, and the alignment control unit 71 controls the left-right movement mechanism 40X and/or the up-down movement mechanism 40Y to cancel this deviation. The XY alignment is performed, for example, so that the displacement of the XY alignment index relative to the alignment mark is equal to or smaller than a preset value. The determination unit 72 determines whether the XY alignment is completed.

(S4, S5: Perform Z alignment)
When the XY alignment in step S3 is completed, the alignment control unit 71, the data processing unit 50, and the moving mechanism 40 execute Z alignment based on the Z alignment index whose generation started in step S2.

In other words, the data processing unit 50 determines the deviation in the Z direction by referring to the Z alignment index, and the alignment control unit 71 controls the forward/backward movement mechanism 40Z to cancel this deviation, while controlling the up/down movement mechanism 40Y (and/or left/right movement mechanism 40X) to correct the deviation in the Y direction (and/or X direction) that accompanies the movement in the Z direction. Here, the deviation in the Y direction (and/or X direction) that accompanies the movement in the Z direction is due to the angle θ between the Z direction and the optical axis of the composite optical path OP.

In this embodiment, the first control amount calculation unit 51 of the data processing unit 50 calculates the Z control amount based on the Z alignment index, and the second control amount calculation unit 52 calculates the Y control amount based on this Z control amount and the above correspondence information or the above relational expression. The alignment control unit 71 can set the movement speed in the Z direction (Z movement speed) and the movement speed in the Y direction (Y movement speed) based on the Z control amount and Y control amount calculated by the data processing unit 50. The alignment control unit 71 controls the front-back movement mechanism 40Z based on the Z control amount and the Z movement speed, and controls the up-down movement mechanism 40Y based on the Y control amount and the Y movement speed, in parallel. This causes the optical unit 20 to move along the optical axis of the composite optical path OP.

Z alignment is performed, for example, so that the Z alignment index is obtained at a predetermined position of the line sensor 33 (a predetermined light detection element in the row of light detection elements included in the line sensor 33). Whether or not the Z alignment is completed is determined by the determination unit 72 (S5).

(S6: Perform inspection)
When it is determined that the Z alignment is completed (S5: Yes), the examination control unit 73 executes control of the examination optical system 21 to acquire data of the subject's eye E. As a result, the examination (measurement, photography, etc.) is started substantially simultaneously with the completion of the alignment. Thus, in this embodiment, the completion of the alignment (Z alignment) is used as an examination start trigger.

An example of such processing will be described with reference to Fig. 4. In this example, the inspection or the operation therefor is repeatedly performed at a predetermined time interval (inspection timing shown in Fig. 4). For example, in corneal endothelial cell photography, an imaging device (CCD image sensor, CMOS image sensor, etc.) repeatedly photographs at a predetermined rate. Such repetitive operations are performed in parallel with Z alignment. The time interval of the inspection or the operation therefor is represented as _ΔT1 .

The alignment confirmation timing shown in Fig. 4 indicates the timing at which the process of determining whether or not Z alignment is complete is repeatedly executed. The time interval of the determination process is represented as _ΔT2 . In this example, it is assumed that Z alignment is completed at time t = _t0 (the "OK" time shown in Fig. 4).

In a conventional ophthalmic device, control is performed so that the examination is performed at the examination timing t= _t1 , which arrives immediately after the time t= _t0 when the Z alignment is completed. For example, the time interval _ΔT1 in typical corneal endothelial cell photography is 33 milliseconds. Therefore, the examination (capturing the photographed image of the corneal endothelial cell) starts at a timing nearly 33 milliseconds after the Z alignment is completed. Therefore, there is a possibility that the alignment state may be shifted during this time. In other words, the difference (Δt= _t1 - _t0 ) between the time t= _t0 when the Z alignment is completed and the time t= _t1 when the examination starts is an obstacle to performing the examination appropriately.

In contrast, in the ophthalmologic apparatus according to this embodiment, the examination control unit 73 causes the examination optical system 21 to perform an examination, triggered by the completion of Z alignment. In the example shown in FIG. 4, the examination control unit 73 sends an instruction to start the examination to the examination optical system 21 in response to the completion of Z alignment (time t=t ₀ ). The time required for this process is set to Δt _a =t _a -t _0. The time Δt _a required to transmit such a signal is sufficiently short, and is at least shorter than Δt. Therefore, the time from the completion of Z alignment to the start of the examination is shorter than in the past, and the possibility of the alignment state being shifted between the completion of Z alignment and the start of the examination is reduced.

The acquired test data (measurement data, image data, etc.) is stored in the storage device of the control unit 70. The test data can also be sent to the external device 11. This completes the processing for this operation example.

<Action and Effects>
The operation and effects of the ophthalmic apparatus according to the embodiment will be described.

The ophthalmologic apparatus according to the embodiment includes an information acquisition unit, a movement mechanism, an index generation unit, a first control unit, a determination unit, and a second control unit.

The information acquisition unit includes an optical system that irradiates light onto the test eye and detects the return light. In one example, the optical axis of the optical system may be inclined with respect to the front-to-back direction (Z direction). That is, the optical axis of the optical system may be arranged non-parallel to the front-to-back direction (may intersect with the front-to-back direction). In another example, the optical axis of the optical system may be arranged parallel to the front-to-back direction. The information acquisition unit acquires test eye information based on data obtained by the optical system. In the above embodiment, the optical system includes the examination optical system 21, and the information acquisition unit includes a test eye information generation unit 53. Also, in the above embodiment, the optical axis of the optical system is the optical axis of the composite optical axis OP.

The moving mechanism moves the optical system. In one example, the moving mechanism can move the optical system in the front-to-back direction (Z direction) and in directions perpendicular to the front-to-back direction (X direction, Y direction) relative to the subject's eye. In the above embodiment, the moving mechanism includes a moving mechanism 40, and the movement in the front-to-back direction is performed by a front-to-back moving mechanism 40Z, while the movement in the direction perpendicular to the front-to-back direction is performed by a left-to-right moving mechanism 40X and a up-to-down moving mechanism 40Y.

The index generating unit generates an index for alignment. For example, the index generating unit generates a first index (Z alignment index) for alignment in the front-rear direction. In the above embodiment, the index generating unit includes a Z alignment system 30.

The first control unit performs alignment by controlling the movement mechanism based on the index generated by the index generation unit. If the optical axis of the optical system is inclined with respect to the front-to-rear direction, the first control unit can control the movement mechanism to move the optical system along the optical axis in Z alignment. In the above embodiment, the alignment control unit 71 and the data processing unit 50 function as the first control unit.

The determination unit determines whether alignment is complete. For example, the determination unit can determine whether alignment using the first index (Z alignment) is complete. In the above embodiment, this corresponds to the determination unit 72.

The second control unit causes the optical system to acquire data in response to the determination unit determining that alignment is complete. In the above embodiment, this corresponds to the inspection control unit 73.

According to such an ophthalmic apparatus of the embodiment, data on the subject's eye can be acquired when the alignment is completed. For example, when synchronous control is performed so that the information acquisition unit can acquire data at a predetermined time interval, in the conventional technology, there is a risk that the subject's eye may move during this time interval. On the other hand, in the ophthalmic apparatus of the embodiment, for example, immediately after the alignment is completed, the synchronous control of the information acquisition unit is interrupted, so that the optical system can acquire data. Therefore, it is possible to perform an examination quickly after the alignment is completed, compared to the conventional case where the user inputs a trigger for data acquisition or the case where the synchronous control of the information acquisition unit is limited. Therefore, according to the ophthalmic apparatus of the embodiment, it is possible to acquire information on the subject's eye in an appropriate alignment state.

In the embodiment, the index generating unit can generate a second index (XY alignment index) for alignment in a direction perpendicular to the front-rear direction. In the above embodiment, the index generating unit includes an XY alignment system 23 in addition to the Z alignment system 30.

The first control unit can control the movement mechanism to move the optical system in a direction perpendicular to the front-to-rear direction based on the second index, and then control the movement mechanism to move the optical system along the optical axis based on the first index. In other words, Z alignment can be performed after XY alignment. In this case, the determination unit can be configured to detect the completion of XY alignment and move on to Z alignment.

The determination unit determines whether the alignment based on the first index (Z alignment) performed after the alignment based on the second index (XY alignment) has been completed. When it is determined that the Z alignment has been completed, the second control unit controls the optical system to acquire data of the subject's eye.

With this configuration, after first aligning the positions in the X and Y directions, Z alignment can be performed so that this preferred positional relationship is maintained. Then, once Z alignment has been completed (i.e., once alignment has been achieved in all of the X, Y, and Z directions), inspection can be performed.

In addition, in alignment using the first index (Z alignment), when the optical system is moved along the direction of the optical axis inclined relative to the front-to-back direction, it is possible to reduce the shaking that occurs in the optical system (ophthalmic device) compared to conventional Z alignment operations that alternate between movement in the Z direction and the associated correction of displacement in the X and Y directions.

In other words, in conventional ophthalmic devices, movement in the Z direction and movement in the XY directions to correct the associated misalignment are repeatedly repeated, causing shaking when the movement starts and stops. Furthermore, the repeated movement and stopping can amplify the shaking. Moreover, the alternating movement in different directions causes irregular and complex shaking. In contrast, with the ophthalmic device of the embodiment, the optical system is moved in a direction that corrects the misalignment in the XY directions associated with movement in the Z direction (i.e., the direction along the optical axis), making it possible to suppress shaking.

As a typical configuration example of such an embodiment, the movement mechanism may include a front-rear movement mechanism (e.g., front-rear movement mechanism 40Z) for moving the optical system in the front-rear direction, a left-right movement mechanism (e.g., left-right movement mechanism 40X) for moving the optical system in the left-right direction relative to the test eye, and a up-down movement mechanism (e.g., up-down movement mechanism 40Y) for moving the optical system in the up-down direction relative to the test eye.

The tilt direction of the optical axis relative to the front-back direction (Z direction) (e.g., the direction indicated by the tilt angle θ) may be the left-right direction (X direction), the up-down direction (Y direction), or a combined direction of the left-right direction and the up-down direction. In other words, the tilt direction of the optical axis may be any direction on the XY plane.

The first control unit may include a first calculation unit (e.g., a first control amount calculation unit 51) and a second calculation unit (e.g., a second control amount calculation unit 52). The first calculation unit calculates a control amount (Z control amount) of the forward/backward movement mechanism based on a first index (Z alignment index). The second calculation unit calculates a control amount of at least one of the left/right movement mechanism and the up/down movement mechanism based on the control amount calculated by the first calculation unit.

Furthermore, the movement mechanism can control the forward/backward movement mechanism based on the control amount calculated by the first calculation unit, and control at least one of the left/right movement mechanism and the up/down movement mechanism based on the control amount calculated by the second calculation unit, in parallel.

In a typical example of a configuration for determining the X control amount and/or the Y control amount from the Z control amount, the first control unit includes a storage unit in which correspondence information is stored in advance that indicates the correspondence between the control amount of the forward/backward movement mechanism and at least one of the control amounts of the left/right movement mechanism and the up/down movement mechanism. The correspondence information may be, for example, table information or a graph. Furthermore, the correspondence information may be prepared for one or more values of the tilt angle θ. In the above embodiment, the storage unit is provided, for example, in the control unit 70, the data processing unit 50, the external device 11, etc. The second calculation unit can determine at least one of the control amounts of the left/right movement mechanism and the up/down movement mechanism based on the control amount determined by the first calculation unit and the correspondence information.

In another typical example, the second calculation unit can use trigonometry to determine the control amount of at least one of the left-right movement mechanism and the up-down movement mechanism based on the control amount determined by the first calculation unit and the tilt angle of the optical axis relative to the front-rear direction. At this time, a calculation formula based on trigonometry (for example, a relational formula between the Z control amount and the Y control amount (and/or the X control amount)) is prepared and stored in advance in the control unit 70, the data processing unit 50, the external device 11, etc.

In an embodiment, the first control unit can substantially simultaneously start and substantially simultaneously end control of the forward/backward movement mechanism and control of at least one of the left/right movement mechanism and the up/down movement mechanism.

This configuration reduces the number of movements and stops, further reducing shaking.

The embodiment described above is merely one example for implementing the present invention. Anyone who wishes to implement the present invention may make any modifications, omissions, additions, etc. within the scope of the gist of the present invention.

Reference Signs List 1 Ophthalmic apparatus 20 Optical unit 21 Examination optical system 22 Observation optical system 23 XY alignment system 30 Z alignment system 40 Movement mechanism 40X Left-right movement mechanism 40Y Up-down movement mechanism 40Z Front-rear movement mechanism 51 First control amount calculation unit 52 Second control amount calculation unit 53 Tested eye information generation unit 70 Control unit 71 Alignment control unit 72 Determination unit 73 Examination control unit

Claims (4)

an information acquiring unit that acquires information about the subject's eye by repeatedly photographing corneal endothelial cells of the subject's eye at a first time interval using an optical system;
an alignment unit that aligns the optical system with the subject's eye;
a determination unit that determines whether the alignment is completed,
The information acquisition unit is
an examination optical system for acquiring a plurality of corneal endothelial cell images including corneal endothelial cell images obtained by the corneal endothelial cell photographing performed repeatedly in parallel with the alignment and corneal endothelial cell images obtained by the corneal endothelial cell photographing performed at the interruption, the corneal endothelial cell photographing being performed at a timing different from the plurality of photographing timings at the first time interval in response to the determination unit determining that the alignment is completed while the corneal endothelial cell photographing is being performed repeatedly in parallel with the alignment and the corneal endothelial cell images obtained by the interrupted corneal endothelial cell photographing.
An ophthalmic apparatus comprising: The ophthalmic apparatus according to claim 1 , wherein the determination unit repeatedly determines whether the alignment is completed at a second time interval. The ophthalmologic apparatus according to claim 1 , wherein an optical axis of the examination optical system is arranged parallel to a front-rear direction. The ophthalmologic apparatus according to claim 1 , wherein an optical axis of the examination optical system is inclined with respect to a front-rear direction.

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