JP2022040228A - Ophthalmologic apparatus and pupil state measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmologic apparatus and a pupil state measuring method that can secure accuracy of a measurement result of objective measurement and are effective for investigating a cause of an error at the time of objective measurement.

SOLUTION: An ophthalmologic apparatus includes: an eye characteristic measuring part for objectively measuring eye characteristics of an eye to be examined of a subject; at least two imaging parts for imaging the anterior eye part of the eye to be examined from different directions substantially simultaneously while the eye characteristics are being measured by the eye characteristic measuring part; a pupil state measuring part for measuring a pupil state of the eye to be examined on the basis of at least two images of images captured by the at least two imaging parts; and a control part for causing the at least two imaging parts to execute imaging of the anterior eye part of the eye to be examined, and causing the pupil state measuring part to execute measurement of the pupil state of the eye to be examined based on the at least two images.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an ophthalmic apparatus and a method for measuring a pupil condition, and more particularly to an ophthalmic apparatus for measuring a pupil condition of an eye to be inspected and a method for measuring a pupil condition.

Patent Document 1 discloses an ocular optical characteristic measuring device including an objective ocular refractive power measuring system (30). In Patent Document 1, an image of the anterior segment of the subject at a target setting position is acquired by an optical power measuring system (30) and a photoelectric detector (37), and the pupil diameter of the subject is determined from the image of the anterior segment of the eye. Calculate. Then, based on the pupil diameter and the like, the aperture aperture of the projection optical system (2) that projects the measured light beam onto the eye to be inspected and the aperture stop of the light receiving optical system (3) that receives the reflected light from the eye to be inspected are selected. An optotype image is acquired by a photoelectric detector (21) via a projection optical system (2) and a light receiving optical system (3) (from [0046] to [0057] in Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-263802

In the conventional ophthalmic apparatus, when the optical characteristics of the eye to be inspected such as the refractive power are objectively measured, it is not possible to measure the state of the pupil of the eye to be inspected during the objective measurement. If miosis of the subject's eye occurs during objective measurement, the measured luminous flux may be blocked by the iris, and if miosis of the subject's eye occurs during objective measurement, the accuracy of the measured value can be ensured. There was a problem that it could not be done. Further, in objective measurement, an error may occur due to miosis of the eye to be inspected, but it has been difficult to determine the cause of this error with a conventional ophthalmic apparatus.

Patent Document 1 discloses that the measurement of the refractive power of the eye to be inspected and the acquisition of the anterior eye portion image used for calculating the pupil diameter are performed by the same photoelectric detector (37). The measurement of the refractive power and the acquisition of the image of the anterior eye portion during the measurement of the refractive power cannot be performed simultaneously by the same photoelectric detector (37).

In addition, Patent Document 1 describes that the front eye portion image may be photographed by the projection optical system (2) and the light receiving optical system (3) (Patent Document 1 [0058]). However, when the refractive power measurement and the imaging of the anterior segment of the eye are performed using different optical systems, there is a problem that the equipment becomes complicated, large in size, and cost increases because a plurality of cameras are required. rice field.

The present invention has been made in view of such circumstances, and it is possible to ensure the accuracy of the measurement result of the objective measurement, and it is an ophthalmic apparatus effective for investigating the cause of the error in the objective measurement. And, an object of the present invention is to provide a method for measuring a pupil condition.

In order to solve the above problems, the ophthalmic apparatus according to the first aspect of the present invention includes an eye characteristic measuring unit for objectively measuring the eye characteristics of the subject's eye, and an eye characteristic measuring unit. Based on at least one image taken by at least two imaging units and at least one imaging unit that captures the anterior segment of the eye under test from different directions substantially simultaneously during the measurement. The pupil condition measurement unit that measures the pupil condition of the eye to be examined and the anterior eye portion of the eye to be examined are photographed by at least two imaging units, and the pupil condition of the eye to be examined is measured based on at least one image. It is provided with a control unit to be executed by the unit.

According to the first aspect, since the state of the pupil during the objective measurement can be detected, the accuracy of the measurement result of the objective measurement can be ensured. Further, according to the first aspect, by measuring the pupil state by using the two imaging units provided for alignment, it is possible to avoid the complicated, large-sized and cost-up of the device.

In the first aspect, the ophthalmic apparatus according to the second aspect of the present invention is a distance detecting unit that detects the distance between the eye characteristic measuring unit and the eye to be inspected based on the images taken by the two imaging units. Further prepare.

The ophthalmic apparatus according to the third aspect of the present invention is a storage unit that stores the measurement result of the eye characteristic by the eye characteristic measurement unit and the measurement result of the pupil state by the pupil condition measurement unit in the first or second aspect. Further prepare.

According to the third aspect, an optometrist (eg, an ophthalmologist, a nurse, an orthoptist, etc.) has a state of the pupil during objective measurement stored in a memory unit at the time of analysis of the measurement result of eye characteristics. Can be referred to. This makes it possible to investigate the cause of the error in measuring the eye characteristics and to ensure the accuracy of the measurement result.

In the ophthalmic apparatus according to the fourth aspect of the present invention, in any one of the first to third aspects, the pupil state measuring unit determines the pupil state, the diameter of the pupil in each meridian direction of the eye to be inspected, and the eye to be inspected. At least one of the eccentricities of the pupil with respect to the apex of the cornea is measured.

In the ophthalmic apparatus according to the fifth aspect of the present invention, in any one of the first to fourth aspects, the control unit controls the eye characteristics measured by the eye characteristics measuring unit while the eye characteristics are measured by at least two imaging units. The image of the anterior eye portion and the measurement of the pupil state of the eye to be inspected based on at least one image among the images captured by at least two imaging units are executed.

According to the fifth aspect, it becomes possible to measure the change with time of the pupil state at the time of measuring the eye characteristics.

In any one of the first to fifth aspects, the ophthalmic apparatus according to the sixth aspect of the present invention notifies the pupil state based on the pupil state of the eye to be inspected during the measurement of the eye characteristics by the eye characteristic measuring unit. Further, a determination unit for determining whether or not the determination unit is provided, and a notification unit for performing notification when the determination unit determines that notification is performed.

In the ophthalmic apparatus according to the seventh aspect of the present invention, in the sixth aspect, the determination unit determines the pupil diameter in at least one meridian direction measured by the pupil state measuring unit from the diameter of the measured luminous flux. When it is equal to or less than the threshold value of, it is determined that the notification is performed.

In the ophthalmic apparatus according to the eighth aspect of the present invention, in the sixth or seventh aspect, the determination unit is the center position of the pupil of the eye to be inspected with respect to the alignment reference position of the pupil of the eye to be inspected measured by the pupil state measurement unit. When the deviation is equal to or greater than the second threshold value determined from the diameter of the measured luminous flux, it is determined that the notification is performed.

Whether or not the ophthalmic apparatus according to the ninth aspect of the present invention performs measurement based on the pupil diameter of the eye to be inspected before the start of measurement of eye characteristics by the eye characteristic measuring unit in any of the first to eighth aspects. A determination unit for determining the above is further provided, and the control unit stops the measurement of the eye characteristics by the eye characteristic measurement unit.

In the ninth aspect, the ophthalmic apparatus according to the tenth aspect of the present invention further includes a notification unit for notifying that the measurement is stopped when the determination unit determines that the measurement is stopped.

The method for measuring the state of the pupil according to the eleventh aspect of the present invention includes an eye characteristic measuring step for objectively measuring the eye characteristics of the subject's eye, and at least two imaging units during the measurement of the eye characteristics. The pupil state of the eye to be inspected is analyzed by analyzing at least one image out of an imaging step of photographing the anterior segment of the eye to be inspected from different directions substantially simultaneously and an image taken by at least two imaging units. It is provided with a measurement step for measuring the eye characteristics and a step for executing an imaging step and a measurement step during the measurement of eye characteristics.

The pupil state measuring method according to the twelfth aspect of the present invention further includes, in the eleventh aspect, a storage step of storing the measurement result of the eye characteristics and the measurement result of the pupil state in the storage unit.

In the eleventh or twelfth aspect of the method for measuring the state of the pupil according to the thirteenth aspect of the present invention, the imaging step and the measuring step are repeatedly executed during the measurement of the eye characteristics.

According to the present invention, since the state of the pupil during objective measurement can be detected, it is possible to ensure the accuracy of the measurement result of objective measurement. Further, according to the present invention, by measuring the pupil state using two imaging units provided for alignment, it is possible to avoid complication, size increase and cost increase of the device.

FIG. 1 is an external view showing an ophthalmic apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing an optical system of an eye examination unit according to an embodiment of the present invention. FIG. 3 is a block diagram showing an ophthalmic apparatus according to an embodiment of the present invention. FIG. 4 is a diagram showing a state in which a stereo camera is mirror-converted with respect to a mirror. FIG. 5 is a top view showing the positional relationship between the eye to be inspected and the stereo camera after the reflection conversion. FIG. 6 is a side view showing the positional relationship between the eye to be inspected and the stereo camera after the reflection conversion. FIG. 7 is a diagram showing an image of an eye to be inspected. FIG. 8 is a flowchart showing a pupil state measuring method according to an embodiment of the present invention.

Hereinafter, embodiments of the ophthalmic apparatus and the pupillary state measurement method according to the present invention will be described with reference to the accompanying drawings.

[Overview of ophthalmic appliances]
FIG. 1 is an external view showing an ophthalmic apparatus according to an embodiment of the present invention.

The ophthalmic apparatus 10 according to the present embodiment is an apparatus capable of performing both objective measurement of the subject's eye and subjective eye examination by the optometry unit 100 (100L and 100R). In the following description, the subject and the optometrist are also referred to as "operators".

As shown in FIG. 1, the ophthalmic apparatus 10 according to the present embodiment includes an optometry table 12, an optometry unit 100 (100L and 100R), and a user interface (UI) 200.

The optometry table 12 is a table whose height can be adjusted according to the body shape and the like of the subject.

A columnar support portion 14 is attached to the optometry table 12 substantially perpendicular to the surface of the optometry table 12. The support portion 14 is configured to be expandable and contractible. By expanding and contracting the support portion 14 according to the body shape and the like of the subject, it is possible to adjust the heights of the eye examination portions 100L and 100R.

An arm portion 16 is attached to the upper end portion of the support portion 14. The arm portion 16 is rotatable around the support portion 14. A hanging portion 18 is attached to the arm portion 16, and eye examination portions 100L and 100R are suspended from the hanging portion 18. The subject or the optometrist can make the eye examination portions 100L and 100R face the subject by rotating the eye examination portions 100L and 100R with respect to the support portion 14.

The suspension unit 18 has a built-in first drive unit 20 (see FIG. 3) for moving the eye examination units 100L and 100R. The operator can move the eye examination units 100L and 100R by operating the first drive unit 20 using the UI 200. The operator can adjust the angles and intervals of the eye examination units 100L and 100R according to the positions and intervals of the left and right eyes of the subject by the first drive unit 20.

The optometry unit 100 (100L and 100R) includes an optical system for measuring and inspecting the left and right eyes of the subject, respectively, and has a binocular simultaneous objective refraction measurement and a subjective eye examination function. When the subject supports the face on the face support portion 24 (see FIG. 3), the left and right eyes are faced directly to the optometry windows of the optometry portions 100L and 100R so that various measurements can be performed. It has become.

The UI 200 includes an operation unit for receiving an operation input from an operator and a display unit for displaying a measurement result by the ophthalmic apparatus 10. In the example shown in FIG. 1, the touch panel display 202 and the controller 204 are shown as the UI 200.

The touch panel display 202 includes a graphical user interface (GUI) for accepting operations, a display screen for displaying measurement results by the ophthalmic apparatus 10, and a touch panel for accepting operations by the operator on the surface of the display screen. It is provided. The touch panel may be any of a matrix switch, a resistance film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and a capacitance method.

The controller 204 includes an operation member (operation button, switch, etc.) that accepts the operation of the operator.

The type of UI 200 is not limited to the touch panel display 202 and the controller 204. The UI 200 may include a pointing device such as a mouse, a keyboard for inputting characters, and the like in place of or in addition to these.

Next, the configurations of the eye examination units 100L and 100R according to the present embodiment will be described. Since the eye examination units 100L and 100R are symmetrical, the eye examination unit 100R for the right eye will be described below, and the description of the eye examination unit 100L for the left eye will be omitted.

FIG. 2 is a diagram showing an optical system of the eye examination unit 100R according to the present embodiment. In the following description, a three-dimensional Cartesian coordinate system is used in which the X direction is the horizontal direction (horizontal direction), the Y direction is the vertical direction (vertical direction), and the Z direction is the direction perpendicular to the XY direction. Here, the Z direction substantially coincides with the line-of-sight direction.

As shown in FIG. 2, the eye examination unit 100R includes a mirror (deflection member) 104, an alignment optical system 106, a stereo camera 108 (cameras (photographing units) 108A and 108B), an objective lens 110, and a measurement optical system 112. Each of these configurations is housed in the ophthalmoscope housing 102.

A substantially circular optometry window 102A is formed in the optometry portion housing 102. A plate-shaped member that transmits light (for example, a member having a relatively high transparency such as white plate glass) may be fitted in the optometry window 102A.

The mirror 104 (deflection member) is arranged on the back side (-Z side) with respect to the optometry window 102A. The mirror 104 is arranged so as to be located in front of the subject when the subject E faces the optometry window 102A, and the right end (+ X side) is on the back side of the optometry window 102A. It is tilted so that it is on the (-Z side). In the present embodiment, the mirror 104 is used as the deflection member, but instead of the mirror 104, an optical member such as a prism capable of deflecting light may be used.

The alignment optical system 106 is arranged in the measurement optical system 112 and includes a light source (for example, a light emitting diode (LED)) and a light projecting lens. The light emitted from this light source is applied to the mirror 104 as parallel light through the objective lens 110. The light emitted to the mirror 104 is reflected by the mirror 104 and is applied to the eye E to be inspected. As a result, the alignment index image is projected on the eye E to be inspected.

The stereo camera 108 includes two or more cameras mounted at different locations in the eye examination unit 100R. The anterior segment of the eye E to be inspected is photographed from different directions substantially simultaneously. By analyzing the positions (feature sites) of the feature points in the two or more anterior eye portion images taken by the stereo camera 108, the positional relationship between the eye to be inspected E and the optometry portion 100R can be obtained. The eye examination unit 100R can be aligned with the eye to be inspected E.

Here, as the feature point on the anterior segment of the eye, a corneal reflex image (Pulkinje image) of the index luminous flux projected on the cornea of the anterior segment of the eye is used, but the present invention is not limited to this, and the center of the pupil or the like may be used.

In the example shown in FIG. 2, the stereo camera 108 is composed of the cameras 108A and 108B of 2, but the number of cameras and the installation location are not limited to the example shown in FIG. One of the cameras 108A and 108B may be arranged in the measurement optical system 112. When the stereo camera 108 is composed of three or more cameras, a part of the stereo camera 108 may be arranged in the measurement optical system 112.

The measurement optical system 112 includes a configuration for measuring the characteristics of the eye E to be inspected. In addition to the alignment optical system 106, the measurement optical system 112 projects an optotype on the eye subject E via the objective lens 110 and the mirror 104, or measures the target eye E via the objective lens 110 and the mirror 104. It includes a projection optical system for projecting light and a light receiving optical system 113 for receiving reflected light.

FIG. 3 is a block diagram showing an ophthalmic apparatus according to the present embodiment.

(Processor 120)
The processor 120 executes various types of information processing. In the present specification, the "processor" is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (for example, a SPLD (Simple Programmable Logic Device), a CPLD (Complex). It means a circuit such as Programmable Logic Device) and FPGA (Field Programmable Gate Array).

The processor 120 realizes the function according to the embodiment, for example, by reading and executing a program stored in a storage circuit or a storage device. At least a portion of the storage circuit or storage device may be included in the processor 120. Further, at least a part of the storage circuit and the storage device may be provided outside the processor 120. The processing that can be executed by the processor 120 will be described later. The processor 120 includes a control unit 122, a storage unit 124, and a data processing unit 126.

(Control unit 122)
The control unit 122 controls each unit of the ophthalmic apparatus 10. In particular, the control unit 122 controls the eye examination units 100L and 100R, the first drive unit 20, and the second drive unit 22. The control that can be executed by the control unit 122 will be described later.

(Storage unit 124)
The storage unit 124 stores various data. As the storage unit 124, for example, a device including a magnetic disk such as an HDD (Hard Disk Drive), a device including a flash memory such as an eMMC (embedded Multi Media Card), an SSD (Solid State Drive), or the like can be used. The data stored in the storage unit 124 includes data (measurement data, imaging data, etc.) acquired by the light receiving optical system of the measurement optical system 112, information on the subject and the eye E to be inspected, and the like. Various computer programs and data for operating the ophthalmic apparatus 10 may be stored in the storage unit 124. Various data used and referred to in the processing described later are stored in the storage unit 124. The storage unit 124 includes the above-mentioned storage circuit and storage device.

(Data processing unit 126)
The data processing unit 126 executes various data processing. In particular, the data processing unit 126 analyzes the captured image acquired by the stereo camera 108.

(Eye examination unit 100)
The eye examination units 100L and 100R store a configuration for measuring and photographing the eye to be inspected E and a configuration for preparing the measurement and imaging thereof. The former includes measurement optical system and the latter includes alignment optical system. The eye examination units 100L and 100R may be provided with a configuration for focusing the measurement optical system 112. Further, the eye examination portions 100L and 100R may include a light source (anterior eye portion illumination light source) for illuminating the anterior eye portion of the eye to be inspected E.

(Measurement optical system 112)
The measurement optical system 112 (eye characteristic measurement unit) includes a configuration for measuring the characteristics of the eye to be inspected E. The measurement optical system 112 has a configuration corresponding to the functions (measurement function, photographing function, etc.) provided by the ophthalmic apparatus 10. For example, in addition to the alignment optical system 106, the measurement optical system 112 is provided with a light source, an optical element (optical member, an optical device), an actuator, a mechanism, a circuit, a display device, a light receiving element, an image sensor, and the like. The configuration of the measurement optical system 112 may be similar to that of the conventional ophthalmic apparatus. The measurement optical system 112 projects an optotype image onto the eye to be inspected E through the objective lens 110 and the mirror 104, projects the measurement light onto the eye to be inspected E through the objective lens 110 and the mirror 104, and receives light. The optical system 113 makes it possible to receive the reflected light. When the measurement optical system 112 has a function of objectively measuring the refractive power of the eye to be inspected, for example, a known optical system of a reflex meter is arranged.

The measurement optical system 112 may be provided with a configuration for providing functions incidental to the inspection. For example, a fixative optical system may be provided that presents an optotype to fix or fog the eye E to be inspected.

(Alignment optical system 106)
The alignment optical system 106 includes a light source and a projection lens, and projects a light flux onto the eye E to be inspected. The light source included in the alignment optical system 106 is arranged in the measurement optical system 112 and projects a parallel light flux onto the cornea of the eye E to be inspected along the optical axis of the objective lens 110. As a result, an index for alignment is projected onto the cornea of the eye E to be inspected. This index is detected as a virtual image (Purkinje image) due to corneal surface reflection. The alignment using the index includes at least the optical axis alignment in the optical axis direction of the measurement optical system 112. Alignment using the index may include XY alignment in the X and Y directions.

In the present embodiment, the optical axis of the measurement optical system 112 is bent by the mirror 104, and the optical axis of the measurement optical system 112 substantially coincides with the Z axis at the position of the mirror image of the measurement optical system 112 with respect to the mirror 104. It is configured to do. Therefore, the alignment of the measurement optical system 112 in the optical axis direction corresponds to Z alignment. In the following description, the alignment of the measurement optical system 112 in the optical axis direction is referred to as Z alignment.

Z alignment is performed by analyzing two or more captured images obtained substantially simultaneously by the stereo camera 108. XY alignment is performed by analyzing two or more captured images obtained by the stereo camera 108.

XY alignment is performed based on the position of the Purkinje image (index image) drawn on two or more captured images in the XY direction. The XY alignment is performed by manually or automatically moving the eye examination unit 100R so as to guide the index image within the allowable range (alignment mark) of the alignment deviation.

In the case of manual alignment, the control unit 122 displays two or more captured images and an alignment mark on the UI 200 (touch panel display 202). The operator operates the UI 200 to move the eye examination unit 100R by the first drive unit 20, and moves the index image within the allowable range of alignment deviation (alignment mark).

In the case of auto-alignment, the data processing unit 126 calculates the displacement of the index image with respect to the alignment mark. The control unit 122 moves the eye examination unit 100R in the XY direction so as to cancel the displacement calculated by the data processing unit 126.

(Stereo camera 108)
The stereo camera 108 includes two or more cameras mounted at different locations in the eye examination unit 100R. Each camera of the stereo camera 108 is, for example, a video camera that shoots a moving image at a predetermined frame rate. Each camera receives the light reflected by the mirror 104 and photographs the anterior eye portion of the eye E to be inspected from different directions substantially simultaneously.

In the example shown in FIG. 2, the cameras 108A and 108B of 2 are provided. Further, the cameras 108A and 108B are arranged at positions deviating from the optical path of the measurement optical system 112, respectively.

The cameras 108A and 108B may be provided below (-Y side) the optical path of the measurement optical system 112. As a result, the reflected light of the luminous flux (index) projected on the anterior eye portion (for example, the cornea) of the eye E to be inspected is less likely to be eclipsed by the eyelashes and eyelids.

The number of cameras included in the stereo camera 108 may be any number of 2 or more, but any number of cameras may be used as long as the front eye portion of the eye to be inspected E can be photographed substantially simultaneously from two different directions. Further, one of the cameras included in the stereo camera 108 may be arranged coaxially with the measurement optical system 112.

Here, "substantially simultaneously" means that in shooting with two or more cameras of the stereo camera 108, a deviation in shooting timing to the extent that eye movements can be ignored is allowed. By photographing the anterior segment of the eye E to be examined from different directions substantially simultaneously with two or more cameras of the stereo camera 108, two or more images taken when the eye E to be inspected is in the same position (orientation) are acquired. Will be possible.

Further, the shooting by the stereo camera 108 may be a moving image shooting or a still image shooting, but in the present embodiment, a case where the moving image shooting is performed will be described. In the case of moving image shooting, the anterior eye portion of the eye E to be inspected is photographed "substantially simultaneously" by each camera by controlling the shooting start timing to be adjusted and the frame rate and the shooting timing of each frame. can do. On the other hand, in the case of still image shooting, by controlling so as to match the shooting timing of each camera included in the stereo camera 108, it is possible to shoot the anterior eye portion of the eye E to be inspected "substantially simultaneously" by each camera. ..

(Face support part 24)
The face support portion 24 includes a member for supporting the face of the subject. For example, the face support portion 24 includes a forehead pad on which the forehead of the subject is abutted and a chin rest on which the chin of the subject is placed. The face support portion 24 may be provided with only one of the forehead rest and the chin rest, and may be provided with a member other than these.

(1st drive unit 20 and 2nd drive unit 22)
The first drive unit 20 moves the eye examination units 100L and 100R under the control of the control unit 122. The first drive unit 20 can move the eye examination units 100L and 100R three-dimensionally, respectively. The first drive unit 20 includes, for example, a mechanism for moving the eye examination units 100L and 100R in the X direction, a mechanism for moving in the Y direction, and a mechanism for moving in the Z direction, as in the conventional case. including. Further, the first drive unit 20 may include a rotation mechanism for rotating the eye examination units 100L and 100R in a plane (horizontal plane, vertical surface, etc.) including the Z axis of the eye examination units 100L and 100R, respectively.

The second drive unit 22 moves the face support unit 24 under the control of the control unit 122. The second drive unit 22 can move the face support unit 24 three-dimensionally. The second drive unit 22 includes, for example, a mechanism for moving the face support portion 24 holding at least one of the subject's forehead and chin, and a mechanism for moving the face support portion 24 in the Y direction. , Includes a mechanism for moving in the Z direction. Further, the second drive unit 22 may include a rotation mechanism for changing the direction of the face support unit 24 (or a member included therein). When a plurality of members are provided on the face support portion 24, the second drive portion 22 may be configured to move these members individually. For example, the second drive unit 22 may be configured to move the forehead rest and the chin rest individually. The ophthalmology device 10 may include only one of the first drive unit 20 and the second drive unit 22, or may include both.

The user interface (UI200) provides functions for exchanging information between the ophthalmic appliance 10 and its user, such as information display, information input, and operation instruction input. The UI 200 provides an output function and an input function. Examples of configurations that provide an output function include a display device such as a flat panel display, an audio output device, a print output device, and a data writer that writes to a recording medium. Examples of configurations that provide input functions include operating levers, buttons, keys, pointing devices, microphones, data writers, and the like. The UI 200 may also include a graphical user interface (GUI) for inputting and outputting information.

In the present embodiment, the UI 200 includes a touch panel display 202 in which an output function and an input function are integrated, and a controller 204.

(Details of data processing unit 126)
The details of the data processing unit 126 will be described. The data processing unit 126 includes an index image detecting unit 128 and a position specifying unit 130.

(Index image detection unit 128)
The index image detection unit 128 detects the index image drawn on each captured image by analyzing two or more captured images obtained substantially simultaneously by the stereo camera 108.

When the cameras 108A and 108B shoot a moving image, the index image detection unit 128 detects the index image from each frame. The index image detection unit 128 detects the index image by analyzing the pixel value of the captured image. When the captured image is a luminance image, the index image detection unit 128 identifies an image region (pixel) corresponding to the indicator image based on the distribution of the luminance values in the captured image. This process includes, for example, a process of selecting a pixel having a luminance value higher than a predetermined threshold value. When the captured image is a color image, the index image detection unit 128 includes, for example, a process of selecting a pixel having a luminance value higher than a predetermined threshold value, or a process of selecting a pixel representing a predetermined color.

(Positioning part 130)
The position specifying unit 130 identifies the position of the eye E to be inspected based on two or more index images detected from two or more captured images acquired substantially simultaneously by the stereo camera 108.

The position specifying unit 130 calculates at least the distance between the eye to be inspected E and the measurement optical system 112 in the Z direction. Z alignment is executed based on this calculation result. Further, the position specifying unit 130 may calculate the displacement between the eye to be inspected E and the measurement optical system 112 in the XY direction. XY alignment is executed based on this calculation result.

Next, the process executed by the position specifying unit 130 according to the present embodiment will be described with reference to FIGS. 4 to 6.

FIG. 4 shows a state in which the cameras 108A and 108B are mirror-converted with respect to the mirror 104, respectively. Hereinafter, the cameras 108A'and 108B' after the reflection conversion will be described.

FIG. 5 is a top view showing the positional relationship between the eye E to be inspected and the cameras 108A'and 108B' after the reflection conversion, and FIG. 6 is a side view.

The distance (baseline length) between the cameras 108A'and 108B' in the XY direction is represented by "B". The distance (index image distance) between the baselines of the cameras 108A'and 108B'and the index image P is represented by "H". The distance (screen distance) between each camera 108A'and 108B'and its screen plane is represented by "f". Generally, when the index luminous flux is projected as a parallel luminous flux with respect to the eye E to be inspected, the index image (Pulkiner image) P is located at a position displaced in the + Z direction from the corneal surface by half of the radius of curvature of the cornea of the eye E to be inspected. It is formed.

In such an arrangement state, the resolution of the images captured by the cameras 108A'and 108B' is expressed by the following equation. Here, Δp represents the pixel resolution.

Resolution in XY direction: ΔXY = H × Δp / f
Resolution in the Z direction: ΔZ = H × H × Δp / (B × f)
The position specifying unit 130 is a known trigonometry in which the arrangement relationship shown in FIGS. 5 and 6 is taken into consideration with respect to the positions (known) of the cameras 108A'and 108B' and the positions of the index images P in the two captured images. By applying, the position of the index image P, that is, the position of the eye to be inspected E is specified. The identified position includes at least a position in the Z direction and may further include a position in the XY direction.

The position of the eye E to be inspected specified by the position specifying unit 130 is sent to the control unit 122. The control unit 122 has the first drive unit 20 and the second drive unit 22 so as to match the distance between the eye to be inspected E and the measurement optical system 112 in the Z direction with the working distance based on the Z position of the eye to be inspected E. Control at least one of them. Further, the control unit 122 has at least one of the first drive unit 20 and the second drive unit 22 so as to align the optical axis of the measurement optical system 112 with the axis of the eye E to be inspected based on the XY position of the eye E to be inspected. To control. The working distance means a predetermined distance between the eye E to be inspected for measuring by the measuring optical system 112 and the measuring optical system 112.

As described above, the position specifying unit 130 can obtain the position of the index image P (Purkinje image) as the position of the eye to be inspected E (approximate position thereof). Further, the position specifying unit 130 can obtain the position of the cornea (vertex) of the eye E to be inspected based on the position of the specified index image P and the radius of curvature of the cornea measured separately. In the state where the XYZ alignment is correct, it is considered that the corneal apex is arranged at a position displaced in the −Z direction by half of the radius of curvature of the cornea from the index image P. Therefore, by subtracting the value of half of the radius of curvature of the cornea from the Z coordinate value of the index image P, the Z coordinate value of the corneal apex (XYZ coordinate value including it) can be obtained.

The radius of curvature of the cornea can be an average radius of curvature r8 mm, but an actual value can also be used as long as the radius of curvature of the cornea of the eye to be examined can be obtained.

The measurement of the radius of curvature of the cornea is performed using a keratometer or a corneal topographer. When the ophthalmic apparatus 10 does not have the function of measuring the radius of curvature of the cornea, the measured value of the radius of curvature of the cornea obtained in the past is input to the ophthalmic apparatus 10. The position specifying unit 130 obtains the position of the corneal apex using this measured value. On the other hand, when the ophthalmic apparatus 10 has a function of measuring the radius of curvature of the cornea, for example, the radius of curvature of the cornea can be measured after performing the alignment, and the alignment can be performed again using the obtained measured value. Further, even when the ophthalmic apparatus 10 has a function of measuring the radius of curvature of the cornea, it is possible to use the measured value of the radius of curvature of the cornea obtained in the past.

(Pupil condition measurement unit 132)
Next, a method of measuring the pupil state will be described with reference to FIG. 7. FIG. 7 is a diagram showing an image of the eye E to be inspected.

As shown in FIG. 7, in the present embodiment, first, the pupil state measuring unit 132 detects the pupil edge L1 from at least one image among the images taken by the stereo camera 108, and determines the boundary coordinates of the pupil E1. calculate. The pupil edge L1 can be detected, for example, based on the difference in brightness between the pupil E1 and the iris E2 in the image of the eye E to be inspected.

In the present embodiment, since the image taken by the stereo camera 108 is used, the viewing angles of the cameras 108A and 108B are taken into consideration when calculating the boundary coordinates of the pupil E1.
In the examples shown in FIGS. 2 and 4, the cameras 108A and 108B are arranged substantially symmetrically in the horizontal direction (X direction) with respect to the front direction of the eye, and thus are caused by the viewing angle in the X direction. In order to remove the deformation (distortion) of the image of the eye, for example, a projection transformation is performed to convert a trapezoidal (or quadrilateral) image obtained by looking at a square from an oblique direction into a square.

Further, when the cameras 108A and 108B are arranged so as to be offset in the Y direction with respect to the front direction of the eye E to be inspected in order to prevent vignetting due to eyelashes or the like, the same conversion is performed in the Y direction as well.

The projection transformation in the X direction and the projection transformation in the Y direction may be performed individually, or may be a composite transformation in which both projection transformations are combined.

Next, the pupil state measuring unit 132 approximates the boundary coordinates of the pupil by an ellipse, and calculates the center, major axis, and minor axis of the pupil approximate ellipse. First, the pupil state measuring unit 132 obtains the coefficients a, b, c, d and h in the general formula [Equation 1] of the ellipse from the boundary coordinates of the pupil by the least squares method.

Next, the pupil state measuring unit 132 obtains the center coordinates of the pupil approximate ellipse by [Equation 2] from the coefficients in the general formula [Equation 1] of the ellipse.

Next, the pupil state measuring unit 132 obtains the inclination angle θ with respect to the X axis of the ellipse by [Equation 3], and obtains the axial lengths of the major axis and the minor axis of the pupil approximate ellipse. In the pupil approximation ellipse, the axis length Ax of the axis tilted by θ with respect to the X axis (hereinafter referred to as the axis in the X direction) and the axis orthogonal to the axis in the X axis direction (hereinafter referred to as the axis in the Y direction). The axial length Ay of is obtained by [Equation 4].

At the same time, the pupil state measuring unit 132 calculates the displacement amount of the center of the pupil with respect to the corneal apex (alignment reference position) obtained by the alignment index.

Next, the flow of the process of measuring the pupil state will be described with reference to FIG. FIG. 8 is a flowchart showing a pupil state measuring method according to an embodiment of the present invention.

In the example shown in FIG. 8, an example in which the pupil state measuring unit 132 repeatedly measures the pupil diameter during objective measurement will be described, but the present invention is not limited thereto. For example, the pupil diameter may be measured only once, and in this case, the presence / absence of miosis and the presence / absence of eccentricity may be determined by comparison with the reference value of the pupil diameter. Further, the measurement results of the pupil diameter and the eccentricity may be output in a format that can be visually recognized by the optometrist, or the miosis or the eccentricity may be automatically detected by the control unit 122. ..

As shown in FIG. 8, after the alignment is completed, first, when the input of the instruction for objective measurement of the refractive power of the eye E to be inspected is received by the UI200 (step S1), the objective refractive power measurement is started and the objective refractive power measurement is started. (Step S10: Refractive power measurement step), measurement of the pupillary state of the eye E to be inspected is started (steps S20 to S32). The objective refractive power measurement and the pupil state measurement are performed by inputting an end instruction from the UI 200 (Yes in step S12 and Yes in step S28) or by ending the objective refractive power measurement (Yes in step S14 and Yes in step S30). Yes) to end.

The pupil state measuring unit 132 measures the pupil state of the eye E to be inspected every predetermined time (for example, 1 to several milliseconds) as an objective refractive power measurement (step S10) (steps S20 to S30).

In step S20, first, the pupil state measuring unit 132 photographs the anterior segment of the eye E to be inspected by the cameras 108A and 108B (imaging step), and performs a projective conversion according to the viewing angle of each camera 108A and 108B. Applies to part images. Next, the pupil state measuring unit 132 obtains the boundary coordinates of the pupil from the anterior eye portion image after the projective conversion, approximates the pupil to an ellipse, and measures the pupil state by [Equation 1] to [Equation 5] (measurement). Process). The pupil state measuring unit 132 stores the measurement results of the pupil diameter and the eccentricity amount in the storage unit 124 (step S22).

Next, the control unit 122 functions as a determination unit for determining whether or not to notify the change in the pupil state (step S24). In step S24, the control unit 122 may use, for example, (1) when the pupil diameter in at least one meridian of the eye to be inspected is equal to or less than the first threshold value, or (2) the pupil diameter in the minor axis direction is the first threshold value. In the following cases, it may be determined that the notification is performed. Further, in step S24, the control unit 122 determines that, for example, (3) notification is performed when the eccentricity (deviation) of the center of the pupil of the subject to be examined exceeds the reference value (second threshold value) with respect to the alignment reference position. You may try to do it. Here, the first and second threshold values can be determined, for example, based on the diameter of the measured luminous flux emitted from the measurement optical system 112 to the eye to be inspected. The conditions for whether or not to perform notification are not limited to the above (1) to (3).

If it is determined to notify (Yes in step S24), the notification is performed (step S26), and the process proceeds to step S28. The notification in step S26 can be performed by various means, but for example, it may be performed by the display on the display screen of the UI 200, or may be performed by using the voice from the speaker.

During the objective refractive power measurement, the measurement of the pupillary state is repeatedly performed at predetermined time intervals (for example, the interval between movements of the eye E to be inspected, several milliseconds) (step S32). Then, it ends when the end instruction is input from the UI 200 (Yes in step S12 and Yes in step S28) or when the objective refractive power measurement ends (Yes in step S14 and Yes in step S30). At the end, the measurement result of the refractive power is stored in the storage unit 124 together with the measurement result of the pupil state (change history of the pupil state) (step S2: storage step).

In the present embodiment, the notification is performed based on the measurement result of the pupillary state during the objective refractive power measurement, but the pupillary state of the eye to be inspected is measured before the start of the objective refractive power measurement. Based on the measurement result, the control unit 122 may stop the measurement of the objective refractive power by the measurement optical system 112. In this case, the measurement may be notified to the effect that the measurement is stopped, or the measurement may be stopped after receiving the operation input from the optometrist or the like after the notification. For example, in FIG. 8, the cycle of steps S20 to S32 may be executed at least once before the start of step S10. The criteria for determining the discontinuation of measurement may be the same as in step S24.

According to the present embodiment, the pupil state in the eye to be inspected during the objective measurement is measured, and the measurement result of the refractive power by the objective measurement and the change history of the pupil state during the objective measurement are stored in association with each other. It is possible. As a result, the state of the pupil during the objective measurement can be detected, so that the accuracy of the measurement result of the refractive power by the objective measurement can be ensured. Further, according to the present embodiment, when an error occurs in the objective measurement, it is possible to investigate the cause of the error from the measurement result of the pupil state. Further, according to the present embodiment, by measuring the pupil state using two cameras 108A and 108B provided for alignment, it is possible to realize simplification, miniaturization and cost reduction of the device. ..

10 Ophthalmology equipment 20 1st drive unit 22 2nd drive unit 24 Face support unit 100, 100L, 100R Eye examination unit 104 Mirror (deflection member)
106 Alignment Optical System 108A, 108B Camera 120 Processor

Claims (8)

An eye characteristic measurement unit that objectively measures the eye characteristics of the subject's eye,
During the measurement of the eye characteristics by the eye characteristic measuring unit, at least two imaging units that photograph the anterior eye portion of the eye to be inspected from different directions substantially simultaneously.
A pupil state measuring unit that measures the pupil state of the eye to be inspected based on at least two images among the images taken by the at least two photographing units.
A control unit that causes the at least two imaging units to perform imaging of the anterior eye portion of the eye to be inspected, and causes the pupil condition measuring unit to perform measurement of the pupil state of the eye to be inspected based on the at least two images.
An ophthalmic device equipped with. A determination unit for determining whether or not to notify the pupil state based on the pupil state of the eye to be inspected during the measurement of the eye characteristics by the eye characteristic measurement unit.
When the determination unit determines that the notification is to be performed, the notification unit that performs the notification and the notification unit
The ophthalmic apparatus according to claim 1. A claim that the determination unit determines to perform the notification when the pupil diameter in at least one meridian direction measured by the pupil state measurement unit is equal to or less than a first threshold value determined from the diameter of the measured luminous flux. 2. The ophthalmic apparatus according to 2. When the determination unit has a deviation of the center position of the pupil of the eye to be inspected with respect to the alignment reference position of the pupil of the eye to be inspected measured by the pupil state measurement unit to be equal to or larger than the second threshold value determined from the diameter of the measured luminous flux. The ophthalmic apparatus according to claim 2 or 3, wherein it is determined that the notification is performed. An eye characteristic measurement process that objectively measures the eye characteristics of the subject's eye,
During the measurement of the eye characteristics, an imaging step of photographing the anterior eye portion of the eye to be inspected from different directions substantially simultaneously by using at least two imaging units.
A measurement step of analyzing at least two images among the images taken by the at least two imaging units to measure the pupillary state of the eye to be inspected.
During the measurement of the eye characteristics, the step of executing the imaging step and the measuring step, and
A method for measuring the state of the pupil. A determination step of determining whether or not to notify the pupil state based on the pupil state of the eye to be inspected during the measurement of the eye characteristics in the eye characteristic measurement step.
When it is determined in the determination step that the notification is to be performed, the notification step of performing the notification and the notification step of performing the notification
5. The method for measuring a pupil state according to claim 5. 6. The sixth aspect of the present invention, wherein the determination step determines that the notification is performed when the pupil diameter in at least one meridian direction measured by the measurement step is equal to or less than the first threshold value determined from the diameter of the measured luminous flux. Pupil condition measurement method. When the determination step is equal to or greater than the second threshold value determined from the diameter of the measured luminous flux, the deviation of the center position of the pupil of the subject to be examined with respect to the alignment reference position of the pupil of the subject to be examined measured by the measurement step is equal to or greater than the diameter of the measured luminous flux. The method for measuring a pupil state according to claim 6 or 7, wherein it is determined to perform the notification.

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