CN113143199A

CN113143199A - Strabismus inspection apparatus

Info

Publication number: CN113143199A
Application number: CN202110479257.XA
Authority: CN
Inventors: 杜煜
Original assignee: Shanghai Qingyan Technology Co ltd
Current assignee: Shanghai Qingyan Technology Co ltd
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2021-07-23
Anticipated expiration: 2041-04-30
Also published as: CN113143199B

Abstract

The invention provides an oblique vision inspection device, which is characterized by comprising: visual target; the image shooting and processing module comprises at least 2 near-infrared cameras and at least 2 near-infrared light sources and is used for continuously shooting images of the eye area; a pupil midline calculation module; and after the alpha and beta are obtained by calculation, the strabismus measurement module judges that strabismus exists if the sizes of the alpha and beta are not equal. The invention has the beneficial effects that: the inspection process is quick and convenient, the time of doctors and examinees can be saved, the inspection result is objective and quantitative, and the method is not only suitable for adults, but also suitable for children and infants.

Description

Strabismus inspection apparatus

Technical Field

The invention relates to strabismus examination equipment, and belongs to the technical field of ophthalmic medical instruments.

Background

Strabismus is a common disease in ophthalmology. If the squint patient can not diagnose and treat in time in the childhood, the appearance is not only influenced, but also visual dysfunction such as amblyopia, double vision, confused vision and the like is easy to cause after the adult.

Currently, the clinically common strabismus examination method is the covering method (cover test) or the corneal reflection method (Hirschberg test).

The main process of the screening method is as follows: enabling the patient to watch the sighting marks, enabling the doctor to cover one eye of the examined person by using the eye covering plate, and observing whether eyeballs of the opposite eyes move or not; then the eye covering plate is removed, and whether the eyeballs covered by the eyes move or not after the eye covering plate is removed is observed. Or covering one eye with an eye shading plate, then rapidly moving to the other eye, repeating for many times, and observing whether the eyeballs move. If the degree of strabismus needs to be measured quantitatively, the triangular prisms with different degrees need to be matched with a covering method for inspection. The masking method requires repeated manual operations by a doctor for many times, and requires the doctor to visually observe the eyeball movement of the examinee, which takes much time. Meanwhile, the examinee needs to keep fit for a long time, and if the examinee is a young child, the cooperation is difficult to be successfully and accurately finished.

The main processes of corneal mapping examination are: let the examinee point of fixation light source, the doctor judges whether squint according to the position that the examinee's eye cornea reflection point deviates from the pupil center, and estimates the degree of squint. The drawback of corneal mapping is that it is not accurate enough and can lead to false positives.

Disclosure of Invention

The purpose of the invention is: a quick and effective strabismus inspection apparatus is provided.

In order to achieve the above object, according to an aspect of the present invention, there is provided an strabismus inspection apparatus, including:

visual target;

the image shooting and processing module comprises at least 2 near-infrared cameras and at least 2 near-infrared light sources and is used for continuously shooting images of the eye area; the image shooting and processing module also comprises an image processing function, and the image processing function is used for carrying out image processing calculation on the shot image of the area; when a left eye image is shot, the image shooting and processing module obtains a left eye pupil center three-dimensional coordinate and each cornea reflection point center three-dimensional coordinate of a left eye through an image processing function; when a right eye image is shot, the image shooting and processing module obtains a right eye pupil center three-dimensional coordinate and each cornea reflection point center three-dimensional coordinate of the right eye through an image processing function; the relative positions of the image shooting and processing module and the sighting target are known;

the pupil center line calculation module is used for calculating the three-dimensional coordinates of the left eye pupil center and the three-dimensional coordinates of each cornea reflection point center of the left eye to obtain the left eye pupil center line; calculating the three-dimensional coordinates of the center of the pupil of the right eye and the three-dimensional coordinates of the centers of all cornea reflection points of the right eye to obtain the pupil center line of the right eye;

the strabismus measurement module is used for enabling the visual targets to be visible for the two eyes of the examinee and enabling the examinee to watch the visual targets; let the left eye pupil center P_lAs a starting point, the ray pointing to the external direction of the eyeball along the middle line of the pupil of the left eye is P_lU; let the left eye pupil center P_lAs a starting point, the ray pointing to the direction of the position C of the sighting mark is P_lC; defining ≈ α as: at the center P of the left eye pupil_lAs a vertex, with a ray P_lU as the starting edge, with ray P_lC is the angle of the terminal edge; let the center P of the right eye pupil_rAs a starting point, the ray pointing in the direction outside the eyeball along the center line of the pupil of the right eye is P_rV; let the center P of the right eye pupil_rAs a starting point, the ray pointing to the direction of the position C of the sighting mark is P_rC; defining ≈ β as: with the center P of the right eye pupil_rAs a vertex, with a ray P_rV is the starting edge, with ray P_rC is the angle of the terminal edge; after the dominant strabismus measuring module calculates and obtains the alpha and beta, if the sizes of the alpha and beta are not equal, the dominant strabismus measuring module judges that dominant strabismus exists.

Preferably, the head three-dimensional coordinate system measuring device further comprises a head three-dimensional coordinate system measuring module, wherein the head three-dimensional coordinate system is established by identifying the characteristic points of the head and calculating the three-dimensional space coordinates of the characteristic points, the X coordinate axis is the left-right direction of the head, the Y coordinate axis is the up-down direction of the head, the Z coordinate axis is the front-back direction of the head, and the origin is at any point of a left-right symmetrical plane of the head;

the strabismus display measuring module obtains the projection angle theta of the angle alpha on the XZ plane in the head three-dimensional coordinate system₁And obtaining the projection of the YZ plane of the < alpha in the three-dimensional coordinate system of the head

The method comprises the steps that a squint measurement module obtains the projection angle theta of the angle beta on an XZ plane in a three-dimensional head coordinate system₂And obtaining the projection of the YZ plane of the < beta in the three-dimensional head coordinate system

The measuring module for displaying squinting is used for comparing the angleθ₁Sum theta₂Direction of or comparison with

And

in the direction of (a) < theta >₁Sum theta₂Not in the opposite direction, or

And

if the directions are not the same, the squint measuring module judges that the squint exists.

The method comprises the steps that a squint measurement module obtains the projection angle theta of the angle beta on an XZ plane in a three-dimensional head coordinate system₂And obtaining the projection of the YZ plane of the < beta in the three-dimensional head coordinate system as

The measuring module for displaying squint compares &₁Sum theta₂Or comparing

And

if theta₁Sum theta₂Not of equal size but of opposite direction, or if

And

if the sizes are not the same and the directions are the same, the strabismus measuring module judges that the strabismus exists.

Preferably, the measuring device further comprises a head bilateral symmetry plane measuring module for measuring a three-dimensional plane equation of the head bilateral symmetry plane;

is arranged to pass through the center P of the left eye pupil_lAnd a line perpendicular to the bilateral symmetry plane of the head intersects the bilateral symmetry plane of the head at W_lPoint, set straight line P_l-W_lPass through the center P of the left eye pupil_lAnd point W_lIs a straight line P_l-W_lA plane is determined by the pupil midline of the left eye and is defined as a left plane, and the left plane is obtained by the strabismus measurement module; definition of [ theta ]_lComprises the following steps: at the center P of the left eye pupil_lAs a vertex, with a ray P_lU as the starting edge, with ray P_lThe projection of C on the left plane is the angle of the final edge, and the oblique display measuring module obtains the angle theta_l(ii) a Definition of

Comprises the following steps: at the center P of the left eye pupil_lAs a vertex, with a ray P_lThe projection of C on the left plane is taken as the initial edge, and the ray P is taken_lC is the angle of the terminal edge, and the measurement module for the strabismus is used for obtaining

Is arranged to pass through the center P of the right eye pupil_rAnd a line perpendicular to the bilateral symmetry plane of the head intersects the bilateral symmetry plane of the head at W_rPoint, then straight line P_r-W_rTo pass through the pupil center P of the right eye_rAnd point W_rIs a straight line P_r-W_rAnd the central line of the pupil of the right eye defines a plane, which is defined as the right plane and is marked with slantThe vision measurement module obtains the right plane; definition of [ theta ]_rComprises the following steps: with the center P of the right eye pupil_rAs a vertex, with a ray P_rV is the starting edge, with ray P_rC, taking the projection of the right plane as the angle of the final edge, and obtaining an angle theta by an oblique display measuring module_r(ii) a Definition of

Comprises the following steps: with the center P of the right eye pupil_rAs a vertex, with a ray P_rC projection on the right plane is taken as the initial edge, and the ray P is taken_rC is the angle of the terminal edge, and the measurement module for the strabismus is used for obtaining

The measuring module for displaying squint compares &_lSum theta_rOr comparing

And

if theta_lSum theta_rNot in the opposite direction, or if

And

Preferably, the head bilateral symmetry plane measuring module is further included, and a three-dimensional plane equation of the head bilateral symmetry plane can be measured;

is arranged to pass through the center P of the left eye pupil_lAnd a line perpendicular to the bilateral symmetry plane of the head intersects the bilateral symmetry plane of the head at W_lPoint, set straight line P_l-W_lPass through the center P of the left eye pupil_lAnd point W_lIs a straight line P_l-W_lA plane is determined by the pupil midline of the left eye and is defined as a left plane, and the strabismus measurement module obtains the left plane; definition of [ theta ]_lComprises the following steps: at the center P of the left eye pupil_lAs a vertex, with a ray P_lU as the starting edge, with ray P_lThe projection of C on the left plane is the angle of the final edge, and the oblique display measuring module obtains the angle theta_l(ii) a Definition of

Is arranged to pass through the center P of the right eye pupil_rAnd a line perpendicular to the bilateral symmetry plane of the head intersects the bilateral symmetry plane of the head at W_rPoint, then straight line P_r-W_rPass through the center P of the right eye pupil_rAnd point W_rIs a straight line P_r-W_rA plane is determined by the central line of the pupil of the right eye and is defined as a right plane, and the right plane is obtained by the strabismus measurement module; definition of [ theta ]_rComprises the following steps: with the center P of the right eye pupil_rAs a vertex, with a ray P_rV is the starting edge, with ray P_rC, taking the projection of the right plane as the angle of the final edge, and obtaining an angle theta by an oblique display measuring module_r(ii) a Definition of

The measuring module for displaying squint compares &_lSum theta_rOr comparing

And

if theta_lSum theta_rNot of equal size but opposite in direction, or if

And

if the sizes are not the same and the directions are not the same, the squint measuring module judges that the squint exists.

Preferably, the strabismus measurement module is further configured to determine a strabismus: setting two eyes as an eye A and an eye B respectively, and enabling the eye B to see the sighting mark and the eye A to not see the sighting mark when the sighting mark is judged to be sighted by the sighting mark measuring module; in the process that the examinee changes the binocular fixation optotype into the B-eye monocular fixation optotype, if the heterophoria measuring module detects that the center line of the pupil of the B eye moves, the heterophoria measuring module judges that the B eye is the heterophoria eye; if the squinting measurement module detects that the central line of the pupil of the eye B does not move in the process, the squinting measurement module judges that the eye A is the squinting eye.

Preferably, the strabismus measurement module is further configured to calculate strabismus and strabismus direction:

one of the two eyes is known to be the oblique eye, and the other eye is known to be the non-oblique eye;

if the strabismus measurement module judges that the left eye is the strabismus eye: setting the projection of the & ltbeta & gt on an XZ plane in the three-dimensional head coordinate system as & lttheta & gt₂The projection of YZ plane in the three-dimensional coordinate system of the head is

The strabismus measuring module is used for measuring the center P of the left eye pupil_lAs a center of rotation, the ray P_lU is along a plane parallel to the XZ plane according to the sum of ° theta₂Rotate in opposite direction to &₂Angle of the same size, resulting in ray P_lU'; then, the strabismus measuring module uses the left eye pupil center P_lThe ray P is taken as the rotation center_lU' along a plane parallel to the YZ plane, according to the sum

Rotate in the same direction as

Angle of the same size, resulting in ray P_lU'; the measuring module for the strabismus obtains the center P of the pupil of the left eye_lAs a vertex, with a ray P_lU' as the starting edge, with ray P_lC is the angle of the final edge, namely the squint angle, the size of the squint angle is the squint degree, and the direction of the squint angle is the squint direction;

if the strabismus display measuring module judges that the right eye is the strabismus: setting the projection of the & lt alpha on the XZ plane in the three-dimensional head coordinate system as & lt theta₁The component of YZ plane in the three-dimensional coordinate system of the head is

The measuring module for the strabismus uses the center P of the right eye pupil_rAs a center of rotation, the ray P_rV is along a plane parallel to the XZ plane according to the sum of ° theta₁Rotate in opposite direction to &₁Angle of the same size, resulting in ray P_rV'; then, the measuring module for the strabismus uses the center P of the right eye pupil_rThe ray P is taken as the rotation center_rV' along a plane parallel to the YZ plane, according to the sum

Rotate in the same direction as

Angle of the same size, resulting in ray P_rV'; the measuring module for the strabismus obtains the center P of the pupil of the right eye_rAs a vertex, with a ray P_rV' is the starting edge, with ray P_rAnd C is the angle of the final edge, namely the squint angle, the size of the squint angle is the squint degree, and the direction of the squint angle is the squint direction.

Preferably, the strabismus measuring module is further configured to calculate strabismus;

setting the projection of the & ltbeta & gt on an XZ plane in the three-dimensional head coordinate system as & lttheta & gt₂The projection of YZ plane in the three-dimensional coordinate system of the head is

Rotate in the same direction as

Angle of the same size, resulting in ray P_lU'; the strabismus measurement module calculates to obtain a ray P_lU' and ray P_lThe size of the included angle C is taken as the strabismus;

or, the projection of the & lt alpha on an XZ plane in the three-dimensional head coordinate system is & lt theta 1, and the component of a YZ plane in the three-dimensional head coordinate system is

Rotate in the same direction as

Angle of the same size, resulting in ray P_rV'; the strabismus measurement module calculates to obtain a ray P_rV' and ray P_rThe size of the angle C is taken as the strabismus.

Preferably, the strabismus measurement module is further configured to calculate strabismus degree and strabismus direction;

if the strabismus measurement module judges that the left eye is strabismus, the strabismus measurement module carries out ray P_lU is according to sum theta along the left plane_rRotate in opposite direction to &_rAngle of the same size, resulting in ray P_lU₁(ii) a Then, the strabismus measuring module uses the left eye pupil center P_lThe ray P is taken as the rotation center_lU₁In a direction perpendicular to the left plane according to the sum

Rotate in the same direction as

Angle of the same size, resulting in ray P_lU₂(ii) a The measuring module for the strabismus obtains the center P of the pupil of the left eye_lAs a vertex, with a ray P_lU₂Starting with a ray P_lC is the angle of the final edge, namely the squint angle, the size of the squint angle is the squint degree, and the direction of the squint angle is the squint direction;

if the strabismus measurement module judges that the right eye is the strabismus eye, the strabismus measurement module carries out ray P_rV is according to sum theta along the left plane_lRotate in opposite direction to &_lAngle of the same size, resulting in ray P_rV₁(ii) a Then, the measuring module for the strabismus uses the center P of the right eye pupil_rThe ray P is taken as the rotation center_rV₁In a direction perpendicular to the right plane according to the sum

Rotate in the same direction as

Angle of the same size, resulting in ray P_rV₂(ii) a The measuring module for the strabismus obtains the center P of the pupil of the right eye_rAs a vertex, with a ray P_rV₂Starting with a ray P_rAnd C is the angle of the final edge, namely the squint angle, the size of the squint angle is the squint degree, and the direction of the squint angle is the squint direction.

Preferably, the strabismus measurement module is further configured to calculate strabismus;

the strabismus measuring module is used for measuring rays P_lU is according to sum theta along the left plane_rRotate in opposite direction to &_rAngle of the same size, resulting in ray P_lU₁(ii) a Then, the strabismus measuring module uses the left eye pupil center P_lThe ray P is taken as the rotation center_lU₁In a direction perpendicular to the left plane according to the sum

Rotate in the same direction as

Angle of the same size, resulting in ray P_lU₂(ii) a The strabismus measurement module calculates to obtain a ray P_lU₂And ray P_lThe size of the included angle C is taken as the strabismus;

or the strabismus measurement module measures the ray P_rV is according to sum theta along the left plane_lRotate in opposite direction to &_lAngle of the same size, resulting in ray P_rV₁(ii) a Then, the strabismusThe measuring module uses the center P of the right eye pupil_rThe ray P is taken as the rotation center_rV₁In a direction perpendicular to the right plane according to the sum

Rotate in the same direction as

Angle of the same size, resulting in ray P_rV₂(ii) a The strabismus measurement module calculates to obtain a ray P_rV₂And ray P_rThe size of the angle C is taken as the strabismus.

Preferably, the position of the optotype is fixed;

the system also comprises a heterophoria measuring module, two eyes are respectively an eye A and an eye B, if the heterophoria measuring module does not measure that the examinee has heterophoria, the examinee keeps watching the sighting mark, then the eye A is shielded by a material which is opaque to visible light and transparent to near infrared light, and the image shooting and processing module detects the pupillary midline of the two eyes of the examinee in real time; if the heterophoria measuring module judges that the central line of the A eye pupil moves and the central line of the B eye pupil does not move in the shielding process, the heterophoria measuring module judges that heterophoria exists, and the strabismus degree of the heterophoria is the rotating angle of the central line of the A eye pupil.

Preferably, the visual target display device further comprises a display module capable of displaying the visual target, the position of the visual target display is fixed, and the display module is switched among the following three display modes:

the first display mode is as follows: displaying the optotypes visible to both eyes;

and a second display mode: displaying the optotype visible only to the left eye;

and a third display mode: displaying the optotype visible only to the right eye;

the display module is used for judging the squint, the display module firstly works in a first display mode to display visual targets visible to both eyes, if the display module judges the squint exists, the visual targets displayed by the display module are switched to a second display mode from the first display mode, the positions of the visual targets are unchanged, and the examinees can watch the visual targets; the image shooting and processing module detects the pupillary midline of two eyes of the examinee in real time, and if the mydriasis measuring module judges that the pupillary midline of the two eyes of the examinee does not move in the process of switching from the display mode I to the display mode II, the right-eye mydriasis is judged; if the central lines of the pupils of the two eyes of the examinee are judged to move by the strabismus measuring module in the process of switching from the first display mode to the second display mode, the strabismus of the left eye is judged;

or the sighting target displayed by the display module is switched to a display mode III from the display mode, and the position of the sighting target is unchanged, so that the examinee can watch the sighting target; the image shooting and processing module detects the pupillary midline of two eyes of a detected person in real time, and if the pupillary midline of the two eyes of the detected person is not moved in the process of switching from the first display mode to the third display mode, the strabismus measuring module judges the strabismus of the left eye; if the central lines of the pupils of the two eyes of the examinee are judged to move by the strabismus measuring module in the process of switching from the display mode I to the display mode III, judging that the right eye is strabismus;

the system also comprises a heterophoria measuring module, and if the heterophoria measuring module does not measure that the examined person has heterophoria, the heterophoria measuring module is operated;

the sighting target displayed by the display module is switched to a second display mode from the display mode, and the position of the sighting target is unchanged, so that the examinee can watch the sighting target; the image shooting and processing module detects the pupillary midline of two eyes of the examinee in real time, and if the pupillary midline of the two eyes of the examinee is not moved in the process of switching from the display mode I to the display mode II, the heterophoria measuring module judges that no heterophoria exists; if the central line of the left eye pupil of the examinee is not moved and the central line of the right eye pupil is moved in the process of switching from the first display mode to the second display mode, the heterophoria is judged to exist, and the strabismus degree is the angle of rotation of the central line of the right eye pupil;

or the sighting target displayed by the display module is switched to the display mode three from the display mode, and the position of the sighting target is unchanged, so that the examinee can keep watching the sighting target; the image shooting and processing module detects the pupillary midline of two eyes of the examinee in real time, and if the pupillary midline of the two eyes of the examinee is not moved in the process of switching from the display mode I to the display mode III, the heterophoria measuring module judges that no heterophoria exists; if the central line of the pupil of the right eye of the examinee is not moved and the central line of the pupil of the left eye is moved in the process of switching from the first display mode to the third display mode, the heterophoria is judged to exist, and the strabismus degree is the rotating angle of the central line of the pupil of the left eye.

Preferably, the display module is a display device capable of displaying visible light with two different wavelengths, or a naked eye 3D display device, or a polarization display device, or a shutter display device.

Preferably, the sighting mark is a lamp capable of emitting light.

Preferably, the sighting mark is a lamp capable of emitting white light;

still include a visible light camera, be located with the position that the sighting mark distance is close, when carrying out the inspection of the strabismus, when the sight is fixed at to the person of examinee's eyes, shoot with this visible light camera to eyes in step.

Preferably, the visual target is three closely arranged lamps, wherein one lamp can emit white light and one lamp can emit light with a wavelength lambda₁A lamp emitting light of wavelength lambda₂Of visible light, λ₁Is not equal to lambda₂；

The filter also comprises two optical filters, wherein the left optical filter can transmit light with the wavelength of lambda₁The right filter can transmit the visible light and the near infrared light with the wavelength of lambda₂Visible light and near infrared light.

Preferably, the device further comprises a distance sensor for prompting the distance between the strabismus examination device and the subject in real time.

Preferably, the strabismus inspection device is a portable handheld device; the number of the near-infrared cameras is 2, and the near-infrared cameras are symmetrically distributed on the left side and the right side of the strabismus inspection equipment; the number of the near-infrared light sources is 2, and the near-infrared light sources are symmetrically distributed on the left side and the right side of the strabismus examination.

Preferably, the strabismus inspection equipment is portable handheld strip-shaped equipment, and the sighting mark is located at the midpoint of the strabismus inspection equipment; the number of the near-infrared cameras is 2, the near-infrared cameras are distributed on two sides of the strabismus inspection equipment and have the same distance with the midpoint of the strabismus inspection equipment; the number of the near infrared light sources is 2, the near infrared light sources are distributed on two sides of the strabismus inspection equipment and have the same distance with the midpoint of the strabismus inspection equipment; the sighting target, the 2 near-infrared cameras and the 2 near-infrared light sources are distributed on the same straight line.

Preferably, the strabismus examination equipment is head-mounted, and at least two near-infrared cameras and at least two near-infrared lamps are arranged near the left eye and can shoot the left eye; the at least two near-infrared cameras and the at least two near-infrared lamps are arranged near the right eye, and the right eye can be shot; the head-mounted device can measure the relative position of the optotypes in real time.

The invention has the beneficial effects that: the inspection process is quick and convenient, the time of doctors and examinees can be saved, the inspection result is objective and quantitative, and the method is not only suitable for adults, but also suitable for children and infants.

Drawings

FIG. 1 is a schematic diagram showing the positions of the components of the apparatus according to the first embodiment;

FIG. 2 is a schematic diagram showing the relative positions of the display, 2 cameras, 2 light sources, and left and right eyes according to the first embodiment;

FIG. 3 is a schematic diagram of the three-dimensional positioning principle of the pupil center by the two-camera system;

FIG. 4 is a schematic diagram of the pupil centerline calculation;

FIG. 5 is a schematic view of the visual axis and the pupil center line of a subject with no strabismus when viewing the target with both eyes;

FIG. 6(a) is a schematic diagram of the visual axis and the pupil center line when the examinee with strabismus left eye views the target in both eyes;

fig. 6(b) is a schematic diagram of ═ α and ≤ β when the eyes of the subject with strabismus on the left eye see the eyes;

fig. 7 is a schematic diagram of judging whether there is a strabismus by comparing the directions of ≈ α and ≥ β;

FIG. 8 is a schematic diagram of a portable, handheld, strabismus inspection device including a beacon light;

FIG. 9 is a schematic diagram of a portable, handheld, strabismus inspection device including three sighting target lights.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example one

As shown in fig. 1, the strabismus examination device provided by the embodiment includes a visual target, an image capturing and processing module, a pupil center line calculating module, and a strabismus measuring module. Wherein the optotypes are displayed on the display 1. The system also comprises an electronic computer 2, and an image processing algorithm of the image shooting and processing module 7, a pupil middle line calculating module and a strabismus measuring module are programs running on the electronic computer 2.

In this embodiment, the image capturing and processing module 7 includes 2 near-infrared cameras, namely a left camera 3 and a right camera 4, and further includes 2 near-infrared LED point light sources with a light emitting wavelength of 940nm, namely a left light source 5 and a right light source 6, which are located outside the near-infrared cameras. The image capture and processing module 7 is located below the display 1, with the camera and light source housed in the housing. The relative positions of the 2 near-infrared cameras and the 2 near-infrared light sources are fixed and known. The relative position between the image capture and processing module 7 and the display 1 in this embodiment is fixed and known, and the size of the display 1 is known. The relative positional relationship of the left camera 3, the right camera 4, the left light source 5, the right light source 6, the left eye 8 and the right eye 9 in the image capturing and processing module 7 is shown in fig. 2.

The operation of the equipment comprises the following specific steps:

taking a subject with strabismus as an example, the left eye is the strabismus eye, and the right eye is the non-strabismus eye. Strabismus, also known as dominant strabismus, is a deviation in eye position that cannot be controlled by the fusion mechanism. The examinee sits in front of the apparatus disclosed in the present embodiment with his eyes facing the display 1. The visual target C is displayed on the display 1, the visual target C is a small circular dot and is located in the center of the display 1, and the visual target C can be seen by both eyes of the examinee. Let the subject look at optotype C.

(II) calculating the pupil central line of the left eye and the pupil central line of the right eye by using a pupil central line calculating module

The two near infrared cameras in the image capture and processing module 7 can capture images containing the eye area. The binocular camera system composed of the left camera 3 and the right camera 4 can perform the calculation of the three-dimensional space coordinates based on the parallax information of the same object.

As shown in fig. 3, with the center P of the right eye pupil_rThree-dimensional space coordinate P_rThe (X, Y, Z) calculation method is taken as an example, the three-dimensional space coordinate takes the optical center E of the left camera 3 as an origin, the straight line where the connecting line EI from the optical center of the left camera 3 to the optical center of the right camera 4 is located is the X axis, the straight line where the optical axis EH of the left camera 3 is located is the Z axis, and the Y axis is perpendicular to the XZ plane (not shown in the figure). The distance between the left camera 3 and the right camera 4 is T, F is the center of the imaging plane of the left camera 3, and J is the center of the imaging plane of the right camera 4. Pupil center P of right eye_rThe imaging point on the left camera 3 is G and the imaging point on the right camera 4 is K. Because the size of the imaging plane of the camera is known, the X-axis distance between a certain imaging point and the center of the imaging plane is easy to calculate. The distance between the G point and the F point on the projection in the X-axis direction is GF, and the distance between the K point and the J point on the projection in the X-axis direction is JK.

Let EF ═ IJ ═ f.

Obtaining an equation (r) and an equation (c) according to a similar triangle principle as follows:

because the equations (r) and (r) have only two unknown quantities x and z, and the other values GF, JK, f, T are known, the solution can be found:

in the same way, according to the pupil center P of the right eye_rThe distance between the imaging point and the center of the imaging plane in the Y-axis direction (the distance is Δ Y) is used to obtain the pupil center P of the right eye_rY-axis coordinate Y:

such that the right eye pupil center P_rThree-dimensional space coordinate P_r(x, y, z) are calculated. The same method can calculate the center P of the left eye pupil_lThree-dimensional space coordinates of

The outer side of the pupil has a spherical corneal surface. The outer surface of the cornea of the human eye is regarded as a convex mirror, and the point light source forms a virtual image on the other side of the convex mirror through the reflection of the convex mirror. Based on optical imaging principles, it is known that the position of the virtual image is determined by the position of the light source and the convex mirror, independent of the position of the observer (i.e. independent of the position of the camera). In addition, a spatial straight line formed by connecting the point light source and the virtual image passes through the spherical center of the spherical surface where the convex mirror is located.

As shown in fig. 4, when the examinee gazes at the optotype C, taking the right eye as an example, based on the optical principle of the point light source convex mirror reflection imaging and the binocular vision principle, the three-dimensional spatial positions of two near-infrared point light sources are set to R₁And R₂The outer surface of the cornea can be calculatedThe three-dimensional space position of the virtual images of the two near-infrared reflecting points is R₁' and R₂'。R₁-R₁' connection and R₂-R₂The connecting line of the' intersects with the spherical center O of the spherical surface on which the outer surface of the cornea is positioned_c. In addition, the pupil center P of the right eye has been measured in the previous step_rThree-dimensional coordinates of (a). Connecting the pupil center P of the right eye_rAnd the center of sphere O_cIs the right eye pupil midline.

The same method can calculate the center P of the left eye pupil_lAnd a three-dimensional linear equation of the midline of the left eye pupil.

(III) judging whether the strabismus exists by using a strabismus measuring module

As shown in fig. 5, the left and right eye visual axes are shown by solid lines and the left and right eye pupil center lines are shown by dashed lines, if a person has no strabismus in both eyes, when the person looks at the optotype C in both eyes, both the left eye visual axis and the right eye visual axis will intersect the point C. The midline of the pupil is the axis of symmetry of the eyeball. Most of the human eyes have their visual axes not completely coincident with the pupil midline, and the included angle between the pupil midline and the visual axis is Kappa angle (e.g. Kappa angle is zero if the visual axes are completely coincident with the pupil midline). According to the principle of physiological symmetry of the left and right eyes, the left and right Kappa angles are equal in size and opposite in direction (the opposite direction means that when looking from top to bottom, if the relative rotation direction of the pupil center line and the visual axis of one eye is clockwise, the relative rotation direction of the pupil center line and the visual axis of the other eye is counterclockwise).

As shown in fig. 6(a), since the examinee in the present embodiment is strabismus for the left eye and non-strabismus for the right eye, when the examinee simultaneously observes the optotype C with both eyes, the visual axis of the right eye intersects with the position of the optotype C, and since the left eye is strabismus, the straight line on which the visual axis of the left eye intersects with the position of the optotype C, and the visual axis of the left eye intersects with the display plane at the point D; the left eye pupil midline intersects the display plane at point U, and the right eye pupil midline intersects the display plane at point V. Since the relative positions of the left and right cameras in the image capture and processing module and the optotype C are known, the three-dimensional spatial coordinates of the optotype C are known. As shown in FIG. 6(b), let us say the center P of the pupil of the left eye_lAs a starting point, the ray pointing to the external direction of the eyeball along the middle line of the pupil of the left eye is P_lU; let the left eye pupil center P_lAs a starting point, the ray pointing to the direction of the position C of the sighting mark is P_lC; defining ≈ α as: at the center P of the left eye pupil_lAs a vertex, with a ray P_lU as the starting edge, with ray P_lC is the corner of the terminal edge. Let the center P of the right eye pupil_rAs a starting point, the ray pointing in the direction outside the eyeball along the center line of the pupil of the right eye is P_rV; let the center P of the right eye pupil_rAs a starting point, the ray pointing to the direction of the position C of the sighting mark is P_rC; defining ≈ β as: with the center P of the right eye pupil_rAs a vertex, with a ray P_rV is the starting edge, with ray P_rC is the corner of the terminal edge.

If both eyes of the detected person have no strabismus, the sizes of the alpha and the beta are equal and are both equal to the size of the Kappa angle. Therefore, if the sizes of the alpha and beta are not equal, the condition that the detected person has the strabismus can be judged. Considering that the measured error and the eyeball have a certain degree of jitter, an angle threshold value can be set, and the absolute value of the angle difference between the alpha and the beta can be considered to be equal when the absolute value is smaller than the angle threshold value. The angle threshold may generally be set to a range between 1 ° and 3 °. The present embodiment sets the angle threshold to 2 °. In the present embodiment, as an example from fig. 6(b), the size of ℃.,. beta.is measured to be 12 °, 5 °, and the absolute value of the angular difference is 7 °, which is greater than the angular threshold value, and thus it is determined that the subject has a strabismus.

For most patients with strabismus, the strabismus can cause the sizes of the alpha and the beta to be unequal, but for some special conditions, the sizes of the alpha and the beta of the patients with strabismus are equal. As shown in fig. 7, when one subject watches optotype C with both eyes, the visual axis of the left eye and the display plane intersect at point D', obviously the left eye is marked with strabismus, and the size of ≈ α is just equal to ≈ β. Therefore, in order to further improve the accuracy of judging the strabismus, the invention can also judge whether the strabismus exists by comparing the directions of the alpha and the beta.

For example, one way to compare the ≈ α and ═ β directions is:

the equipment also comprises a head three-dimensional coordinate system measuring module which can establish a head three-dimensional coordinate system by identifying the characteristic points of the head and calculating the three-dimensional space coordinates of the characteristic points. In this embodiment, the head three-dimensional coordinate system measurement module is a program running on the electronic computer 2, and performs three-dimensional space positioning on each feature point of the head of the subject by using a binocular camera formed by two near-infrared cameras in the device, and the identification of each feature point of the head may use a commonly used face recognition algorithm. The center point of the temporal canthus of the left eye and the temporal canthus of the right eye is used as the origin of a three-dimensional head coordinate system, the direction in which the origin points to the temporal canthus of the left eye is used as the direction of the X axis of the three-dimensional head coordinate system, the direction in which the origin points to the opposite direction of the center point of the chin is the direction of the Y axis, and the direction in which the origin points to the front of the head in a direction perpendicular to the XY plane is the direction of the Z axis. The projection of the angle alpha on the XZ plane measured by the strabismus measurement module is angle theta₁The projection of the angle alpha on the YZ plane is

The projection of the angle beta on the XZ plane measured by the strabismus measuring module is angle theta₂The projection of the angle beta on the YZ plane is

If theta₁Sum theta₂Not in the opposite direction, or

And

if the directions are not the same, the squinting is judged to be present. In this way, for the example of fig. 7, it can be measured that the XZ plane projection of izeand the XZ plane projection of izeare not opposite in direction but in the same direction (the left eye pupil center line is clockwise with respect to the left eye visual axis, and the right eye pupil center line is also clockwise with respect to the right eye visual axis), so that it can be determined that the subject has strabismus.

In addition, the projection size and the projection direction of the alpha and the beta on the XZ plane and the YZ plane can be simultaneously comparedAnd (3) direction. If theta₁Sum theta₂Not of equal size but of opposite direction, or

And

if the sizes are not the same and the directions are the same, the squinting is judged to be present.

In this embodiment, the strabismus measurement module can also determine which eye strabismus. When having checked and confirm that the person of being examined is for showing the strabismus, if need further judge which eyes are the strabismus, the doctor can let the person of being examined two eyes watch the sighting mark earlier, then shelter from arbitrary one eye with the eye shielding plate of opaque visible light, then observe whether the eye that does not shelter from takes place to remove in another one, judge. For example, the examinee is allowed to watch the optotype with both eyes, then the left eye is shielded, so that only the right eye can see the optotype, and if the right eye moves at the moment, the right eye is indicated as the strabismus eye; if the right eye does not move, the left eye is shown as an oblique eye. If the right eye is blocked, only the left eye can see the sighting mark, and if the left eye moves at the moment, the left eye is the oblique eye; if the left eye does not move, the right eye is shown as an oblique eye. Besides the doctor visually observing whether the unshielded eyes move, the image shooting and processing module 7 of the device can be used for judging whether the pupil centers of the unshielded eyes move or not, or the pupil center line calculating module is used for judging whether the pupil center lines of the unshielded eyes move or not. In this way, in the present embodiment, it can be determined that the oblique eye of the subject is the left eye.

In this embodiment, the strabismus display measuring module in the strabismus checking device may further calculate strabismus degree and strabismus direction. Because the left eye of the detected person is the squinting eye, the component of the angle beta on the XZ plane of the head three-dimensional coordinate system is set as angle theta₂The component in the YZ plane being

Setting the projection of the & lt beta on the XZ plane of the head three-dimensional coordinate system as & lt theta₂The projection of the YZ plane in the three-dimensional head coordinate system is

At the center P of the left eye pupil_lAs a center of rotation, the ray P_lU is along a plane parallel to XZ according to sum theta₂Rotate in opposite directions (for example, clockwise and anticlockwise from top to bottom) and theta₂Angle of the same size, resulting in ray P_lU'; then the center P of the left eye pupil_lThe ray P is taken as the rotation center_lU' along a plane parallel to YZ, according to sum

Rotate in the same direction (e.g., both clockwise and both counterclockwise when viewed from left to right) and

angle of the same size, resulting in ray P_lU'; with P_lAs a vertex, with a ray P_lU' as the starting edge, with ray P_lC is the angle of the terminal edge, namely the squint angle, the size of the squint angle is the squint degree, and the direction of the squint angle is the squint direction. In this embodiment, ray PlC is directly to the right (nasal) of ray PlU ", indicating that the patient is in oblique view. The angle unit can also be converted into a corresponding prism degree unit according to the squint degree angle and the distance of the sighting mark.

For some cases, for example, the examinee is not matched with the shielding monocular for examination due to the reason of being young, and therefore, which eye is the strabismus eye cannot be judged, and the strabismus measuring module can directly calculate the strabismus degree. For example, let the projection of ≦ β on the XZ plane of the three-dimensional head coordinate system be ≦ θ₂The projection of the YZ plane in the three-dimensional head coordinate system is

At the center P of the left eye pupil_lAs a center of rotation, the ray P_lU is along a plane parallel to XZ according to sum theta₂Rotate in opposite directions (for example, clockwise and anticlockwise from top to bottom) and theta₂Same sizeAngle, get ray P_lU'; then the center P of the left eye pupil_lThe ray P is taken as the rotation center_lU' along a plane parallel to YZ, according to sum

angle of the same size, resulting in ray P_lU'; by the center P of the eye pupil_lAs a vertex, with a ray P_lU' as the starting edge, with ray P_lThe angle at which C is the terminal edge is in strabismus. In this method, since it is unknown which eye is an oblique eye, only the magnitude of the degree of strabismus can be calculated, and the direction of strabismus cannot be determined.

It should be noted that although the optotype used in the present embodiment is an image displayed on the display 1, the optotype used in the present apparatus may be used as long as the relative positions of the optotype and the image capturing and processing module 7 are known. For example, the optotypes may also be printed or printed two-dimensional images; small objects that can be three-dimensional; may be a small light that emits light; may be a pattern projected by a projector. In addition, the sighting target image displayed by the display 1 can also be a flashing image or animation, so that the attention of young and active children can be better attracted; the display position of the sighting target image can also be moved, only the real-time position of the sighting target image display is controlled by a program on the equipment, and the relative positions of the sighting target image and the image shooting and processing module 7 are known. The sighting target can be displayed at different positions to carry out strabismus examination in different directions; the squint inspection in different directions can be carried out through the whole mobile equipment; different orientations of the strabismus examination can also be performed by having the subject turn the head. The device can also be a portable small device, the size of the device is similar to a tablet personal computer or a mobile phone, a miniaturized image shooting and processing module is integrated, the sighting target is displayed on a display screen, and an image processing algorithm of the image shooting and processing module, a pupil midline calculating module and a strabismus measuring module are programs running on the portable device.

Example two

The strabismus examination equipment disclosed by the embodiment comprises a sighting target, an image shooting and processing module, a pupil midline calculating module and a strabismus measuring module. The working principle and the embodiment of the sighting target, the image shooting and processing module and the pupil center line calculating module are similar.

The equipment also comprises a head bilateral symmetry plane measuring module which can measure a three-dimensional plane equation of the head bilateral symmetry plane. The left and right planes of head symmetry, also known as the midsagittal plane of the head, are symmetric about the left and right planes of symmetry for the left and right halves of the human head. One way that can be used to measure the bilateral symmetry plane of the head is to fix the head of the subject with a head fixation device so that the left and right eyes are at the same height and the distance between the left and right eyes and the midpoint of the 2 near-infrared cameras in the image capture and processing module is the same and the 2 near-infrared camera connecting lines are parallel to the two eye connecting lines. Thus, the left-right symmetrical plane of the head is the middle vertical plane of the connecting line segment of the 2 near-infrared cameras. It can also be measured by a binocular camera in the image capture and processing module. For example, one calculation that may be used is: the binocular camera formed by two near-infrared cameras in the equipment is used for carrying out three-dimensional space positioning on each feature point of the head of the examinee, and the identification of each feature point of the head can use a common face identification algorithm. And taking the midperpendicular of the connecting line segment of the temporal canthus of the left eye and the temporal canthus of the right eye as a head bilateral symmetry plane.

The head bilateral symmetry plane measuring module can also measure the head bilateral symmetry plane through a binocular camera in the image shooting and processing module. For example, one calculation that may be used is: the head bilateral symmetry plane measuring module is a program running on a computer, and carries out three-dimensional space positioning on each feature point of the head of a detected person through a binocular camera formed by two near-infrared cameras in the image shooting and processing module, and the identification of each feature point of the head can use a common face identification algorithm. And taking the midperpendicular of the connecting line segment of the temporal canthus of the left eye and the temporal canthus of the right eye as a head bilateral symmetry plane.

Taking the subject with strabismus as an example in the first embodiment, the left eye is the strabismus eye, and the right eye is the non-strabismus eye.

In the strabismus measuring module, the central point P of the pupil of the left eye is arranged_lAnd a line perpendicular to the bilateral symmetry plane of the head intersects the bilateral symmetry plane of the head at W_lPoint, set straight line P_l-W_lPass through the center P of the left eye pupil_lAnd point W_lIs a straight line P_l-W_lAnd the left eye pupil midline defines a plane, defined as the left plane; definition of [ theta ]_lComprises the following steps: at the center P of the left eye pupil_lAs a vertex, with a ray P_lU as the starting edge, with ray P_lThe projection of C on the left plane is the corner of the terminal edge; definition of

Comprises the following steps: at the center P of the left eye pupil_lAs a vertex, with a ray P_lThe projection of C on the left plane is taken as the initial edge, and the ray P is taken_lC is the corner of the terminal edge.

Is arranged to pass through the center P of the right eye pupil_rAnd a line perpendicular to the bilateral symmetry plane of the head intersects the bilateral symmetry plane of the head at W_rPoint, then straight line P_r-W_rPass through the center P of the right eye pupil_rAnd point W_rIs a straight line P_r-W_rAnd the right eye pupil center line define a plane, defined as the right plane; definition of [ theta ]_rComprises the following steps: with the center P of the right eye pupil_rAs a vertex, with a ray P_rV is the starting edge, with ray P_rC, the projection on the right plane is the corner of the terminal edge; definition of

Comprises the following steps: with the center P of the right eye pupil_rAs a vertex, with a ray P_rC projection on the right plane is taken as the initial edge, and the ray P is taken_rC is the corner of the terminal edge.

If theta_lSum theta_rNot in the opposite direction, or

And

if the directions are not the same, the squinting is judged to be present.

Can also compare the angle theta at the same time_lSum theta_rIf & lt theta & gt_lSum theta_rNot of equal size but opposite in direction, or

And

if the sizes are not the same and the directions are not the same, the squinting is judged to be present.

According to the steps, the squint judging module of the equipment can judge that the detected person is squint.

In this embodiment, the strabismus measurement module can also determine which eye strabismus is. The doctor can let the person of being examined look at the sighting mark with two eyes earlier, then shelter from arbitrary one eye with the eye shielding plate of opaque visible light, then observe whether another eye takes place to remove, judges. For example, the examinee is allowed to watch the optotype with both eyes, then the left eye is shielded, so that only the right eye can see the optotype, and if the right eye moves at the moment, the right eye is indicated as the strabismus eye; if the right eye does not move, the left eye is shown as an oblique eye. If the right eye is blocked, only the left eye can see the sighting mark, and if the left eye moves at the moment, the left eye is the oblique eye; if the left eye does not move, the right eye is shown as an oblique eye. Except that the doctor observes whether the unshielded eyes move or not by naked eyes, the image shooting and processing module of the equipment can be used for judging whether the pupil centers of the unshielded eyes move or not, or the pupil center line calculating module is used for judging whether the pupil center lines of the unshielded eyes move or not. In this way, in the present embodiment, it can be determined that the oblique eye of the subject is the left eye.

In this embodiment, the strabismus display measuring module in the strabismus checking device may further calculate strabismus degree and strabismus direction. Will ray P_lU is according to sum theta along the left plane_rIn the opposite direction (e.g. from top to bottom)To look at a clockwise direction and a counterclockwise direction) and theta_rAngle of the same size, resulting in ray P_lU₁(ii) a Then the center P of the left eye pupil_lThe ray P is taken as the rotation center_lU₁In a direction perpendicular to the left plane according to the sum

angle of the same size, resulting in ray P_lU₂(ii) a At the center P of the left eye pupil_lAs a vertex, with a ray P_lU₂Starting with a ray P_lC is the angle of the terminal edge, namely the squint angle, the size of the squint angle is the squint degree, and the direction of the squint angle is the squint direction. For example, the ray P_lC on ray P_lU₂Right and right (nasal) indicate that the patient is in oblique view. The angle unit can also be converted into a corresponding prism degree unit according to the squint degree angle and the distance of the sighting mark.

For some cases, for example, the examinee is not matched with the shielding monocular for examination due to the reason of being young, and therefore, which eye is the strabismus eye cannot be judged, and the strabismus measuring module can directly calculate the strabismus degree. For example, the ray P_lU is according to sum theta along the left plane_rRotate in opposite directions (for example, clockwise and anticlockwise from top to bottom) and theta_rAngle of the same size, resulting in ray P_lU₁(ii) a Then the center P of the left eye pupil_lThe ray P is taken as the rotation center_lU₁In a direction perpendicular to the left plane according to the sum

angle of the same size, resulting in ray P_lU₂(ii) a Ray P_lU₂And ray P_lThe included angle C is the squint degree.

EXAMPLE III

Phoria, also known as scotopic strabismus, or phoria, is a potential eye deviation that can be controlled by the fusion mechanism, which occurs only when fusion is broken. The equipment can perform the examination of heterophoria besides the examination of heterophoria.

The present embodiment discloses an oblique vision inspection apparatus. The position of the sighting target display is fixed, and the sighting target display device further comprises an image shooting and processing module, a pupil midline calculating module, a strabismus measuring module and a strabismus measuring module. The system also comprises an electronic computer, and the image processing algorithm of the image shooting and processing module, the pupil center line calculating module, the strabismus measuring module and the strabismus measuring module are programs running on the electronic computer. The working principle and the embodiment of the image processing algorithm of the image shooting and processing module, the pupil center line calculating module and the strabismus measuring module are similar.

If the dominant strabismus measurement module does not measure the dominant strabismus of the detected person, the equipment operates the heterophoria measurement module. The method comprises the steps that two eyes are respectively an eye A and an eye B, an examinee keeps watching a visual target, then the eye A is shielded by a material which is opaque to visible light and transparent to near infrared light, the image shooting and processing module detects the pupil center lines of the two eyes of the examinee in real time, if the pupil center line of the eye A moves and the pupil center line of the eye B does not move in the shielding process, the fact that the oblique vision exists is judged, and the oblique vision degree of the oblique vision is the rotating angle of the pupil center line of the eye A.

In this embodiment, the visual target is a white "+" character displayed in the center of the display, and the strabismus measurement module does not measure the strabismus of the subject according to the steps of the first embodiment or the second embodiment. The examinee keeps watching the sighting marks, then the doctor covers the left eye of the examinee by a black acrylic eye shielding plate which is opaque to visible light and transparent to near infrared light, in the covering process, the image shooting and processing module detects the pupillary midline of two eyes of the examinee in real time, and the measuring result is that the pupillary midline of the left eye moves towards the temporal side and the pupillary midline of the right eye does not move. Therefore, the heterophoria measuring module judges that heterophoria exists, the direction of the heterophoria is external heterophoria, and the angle of the heterophoria is the angle of rotation of the central line of the left eye pupil. The angle of heterophoria can also be converted into a triangular prism.

Example four

The strabismus examination device disclosed by the embodiment comprises a display module capable of displaying a sighting target, wherein the display position of the sighting target is fixed, and the display module can be switched among the following three display modes:

the first display mode is as follows: displaying a visual target visible to both eyes;

and a second display mode: displaying a optotype visible only to the left eye;

and a third display mode: the optotype visible only to the right eye is displayed.

The system also comprises an image shooting and processing module, a pupil midline calculating module, a strabismus measuring module and a strabismus measuring module. The system also comprises an electronic computer, and the image processing algorithm of the image shooting and processing module, the pupil center line calculating module, the strabismus measuring module and the strabismus measuring module are programs running on the electronic computer. The working principle and the embodiment of the image processing algorithm of the image shooting and processing module, the pupil center line calculating module and the strabismus measuring module are similar.

For example, the display module is a display, and the display may only display green optotypes, may only display red optotypes, and may also display white optotypes. The examinee wears a pair of red and green glasses (left green and right red) which can transmit near infrared light. When displaying a green icon, only the left eye can see the icon; when the red sighting mark is displayed, only the right eye can see the sighting mark; when the white sighting mark is displayed, the sighting mark can be seen by two eyes.

The display module can also be a naked eye 3D display device, can display visual targets visible only by the left eye, can display visual targets visible only by the right eye, and can display visual targets visible by both eyes.

The display module can also be a polarization display device, the examinee wears corresponding polarization glasses, and the polarization display device can display the optotypes only visible for the left eye, can display the optotypes only visible for the right eye, and can display the optotypes visible for both eyes.

The display module can also be a shutter display device, the examinee wears corresponding shutter glasses, and the shutter display device can display the visual target only visible for the left eye, can display the visual target only visible for the right eye, and can display the visual target visible for both eyes.

In this embodiment, a display capable of displaying green, red and white optotypes is used, and the steps of checking the dominant strabismus and the heterophoria are as follows:

firstly, a white sighting mark is displayed on a display, and the sighting mark is watched by the eyes of a detected person. If the strabismus measurement module judges that the strabismus exists, the sighting mark displayed by the displayer is switched from white to green, and the position of the sighting mark is unchanged, so that the examinee can keep watching the sighting mark. At the moment, the examinee wears red and green glasses, only the left eye can see the green optotype, and the right eye cannot see the green optotype. The image shooting and processing module detects the pupillary midline of two eyes of the examinee in real time, and if the pupillary midline of the two eyes of the examinee does not move in the process of switching from the white sighting mark to the green sighting mark, the right-eye strabismus is judged; if the pupil center lines of the two eyes of the examinee move in the process of switching from the white sighting mark to the green sighting mark, the strabismus of the left eye is judged.

Or, if the strabismus measuring module judges that strabismus exists, the sighting mark displayed by the display is switched from white to red, and the position of the sighting mark is unchanged, so that the examinee can keep watching the sighting mark. If the pupillary midline of the two eyes of the examinee does not move in the process of switching from the white sighting mark to the red sighting mark, judging that the left eye is squinted; if the pupil center lines of the two eyes of the examinee move in the process of switching from the white sighting mark to the red sighting mark, the right-eye strabismus is judged.

And (II) if the white sighting marks are displayed on the display and the dominant strabismus measuring module does not measure the dominant strabismus of the detected person, the equipment operates the heterophoria measuring module. The sighting target displayed by the display is switched from white to green, and the position of the sighting target is unchanged, so that the examinee can keep watching the sighting target. The image shooting and processing module detects the pupillary midline of two eyes of the examinee in real time, and if the pupillary midline of the two eyes of the examinee does not move in the process of switching from the white sighting mark to the green sighting mark, the absence of the heterophoria is judged; if the left eye pupil midline of the examined person does not move and the right eye pupil midline moves in the process of switching from the white sighting mark to the green sighting mark, the examined person is judged to have the heterophoria. The strabismus of heterophoria is the angle of rotation of the right eye pupil midline in the process of switching the white sighting mark to the red sighting mark. The angle of heterophoria can be changed into a triangular prism.

Or the sighting mark displayed on the display is switched from white to red, and the position of the sighting mark is unchanged, so that the examinee can keep watching the sighting mark. If the pupillary midline of both eyes of the examined person does not move in the process of switching from the white sighting mark to the red sighting mark, judging that no heterophoria exists; if the middle line of the pupil of the right eye of the examinee does not move and the middle line of the pupil of the left eye moves in the process of switching from the white sighting mark to the red sighting mark, the examinee is judged to have heterophoria, and the strabismus degree of the heterophoria is the rotating angle of the middle line of the pupil of the left eye in the process of switching from the white sighting mark to the red sighting mark. The angle of heterophoria can also be converted into a triangular prism.

EXAMPLE five

The strabismus examination equipment disclosed by the embodiment comprises a sighting target, an image shooting and processing module, a pupil midline calculating module and a strabismus measuring module.

To facilitate carrying by the doctor, the strabismus examination device may be a portable handheld device. For example, the device can be flat, the number of the near-infrared cameras is 2, and the near-infrared cameras are symmetrical left and right relative to the center line of the device; the number of the near-infrared light sources is 2, and the near-infrared light sources are symmetrical left and right relative to the center line of the equipment. The device may also be strip-shaped, as shown in fig. 8, with the sighting mark located at the midpoint of the device; the number of the near-infrared cameras 11 is 2, and the near-infrared cameras are symmetrical left and right relative to the midpoint of the equipment; the number of the near infrared light sources 12 is 2, and the near infrared light sources are symmetrical to the middle point of the equipment. The sighting target, the near-infrared camera 11 and the near-infrared light source 12 are distributed on the same straight line. In this embodiment, the device is a portable handheld strip device, and the length is 20 cm. Wherein the visual target is a white lamp which is an LED lamp 10 and is positioned at the midpoint of the equipment.

The sighting target lamp can also twinkle to attract the attention of the examinee when the strabismus examination is carried out.

The device may also include a visible light camera located in close proximity to the white LED light 10. When the equipment is used for the strabismus examination, when the eyes of the examinee watch the sight marks, the eyes can be synchronously photographed by the visible light camera, and the photos are stored. The picture is equivalent to the traditional cornea mapping method for taking a picture and can be used as a reference for diagnosis by a doctor.

The device may also include a distance sensor to prompt the doctor or subject to perform the examination within a suitable distance range. For example, if the required distance is 33cm, the distance sensor can feed back whether the distance meets the requirement to the doctor in real time by means of voice prompt or distance information display and the like. The distance measuring mode of the distance sensor can be laser distance measuring, ultrasonic distance measuring, binocular camera optical distance measuring and the like.

The device can also comprise a handle, which is convenient for a doctor to carry out examination by holding the handle.

The device can also comprise a USB interface, the device is connected with the computer through a USB line and is powered through the USB, and the image of the device is transmitted to the computer in real time through the USB for image processing, display and storage. The image processing algorithm of the image shooting and processing module, the pupil center line calculating module and the strabismus measuring module are programs running on a computer.

The equipment can also comprise an embedded computing module, and an image processing algorithm of the image shooting and processing module, a pupil midline computing module and a strabismus measuring module are programs on the embedded computing module. The device also comprises a wireless data transmission module used for transmitting the result data measured by the equipment in real time. A battery is also included for powering the device.

The working principle and the embodiment of an image processing algorithm of an image shooting and processing module, a pupil center line calculating module and a strabismus measuring module in the equipment are similar. Therefore, whether the person being examined has the strabismus can be detected through the equipment, and if the person being examined has the strabismus, which eyes are the strabismus eyes can be further judged, and the direction and the strabismus degree of the strabismus are also judged. The equipment is small in size, convenient to carry, low in cost and particularly suitable for rapid screening in occasions such as hospitals, schools, communities and families.

EXAMPLE six

The strabismus examination equipment disclosed by the embodiment comprises a sighting target, an image shooting and processing module, a pupil midline calculating module and a strabismus measuring module. As shown in fig. 9, the visual target is three visual target lamps, namely a white lamp 13-1, a green lamp 13-2 and a red lamp 13-3, and the three lamps are LED lamps which are closely arranged and are all positioned at the center of the equipment. Other components of the device are similar to those of the fifth embodiment. A pair of red and green glasses (left green and right red) is also provided for the subject to wear, the glasses being transparent to near infrared light. Besides the examination of the heterophoria, the equipment of the embodiment also comprises a heterophoria measuring module, and can be used for examining the heterophoria. The checking steps are as follows:

firstly, a white lamp on the device is turned on, and other lamps are turned off, so that the white lamp can be watched by the eyes of the examinee. If the squint measuring module judges that there is the squint, the white light of equipment goes out, and green light is bright simultaneously, lets the person being examined keep watching the sighting target lamp. At the moment, the examinee wears the red and green glasses, only the left eye can see the green light, and the right eye cannot see the green light. The image shooting and processing module detects the pupillary midline of two eyes of the examinee in real time, and if the pupillary midline of the two eyes of the examinee does not move in the process of switching from the white light to the green light, the right-eye strabismus is judged; if the eyes of the examinee move in the process of switching from the white light to the green light, the left eye is judged to have strabismus.

Or, if the squint measuring module judges that there is the squint, the white light of equipment goes out, and the red light is bright simultaneously, lets the person being examined keep watching the sighting target lamp. If the pupillary midline of both eyes of the examinee does not move in the process of switching from the white light to the red light, judging that the left eye shows strabismus; if the white light is switched to the red light, the pupillary midlines of the two eyes of the examinee move, and the right-eye strabismus is judged.

And (II) if the dominant strabismus measuring module does not measure the dominant strabismus of the detected person when a white lamp on the equipment is on, the equipment operates the heterophoria measuring module. The white light of the equipment is turned off, and the green light is turned on at the same time, so that the examinee can keep watching the sighting target lamp. The image shooting and processing module detects the pupillary midline of two eyes of the examinee in real time, and if the pupillary midline of the two eyes of the examinee does not move in the process of switching from the white light to the green light, the absence of the heterophoria is judged; if the left eye pupil midline of the examinee does not move and the right eye pupil midline moves in the process of switching from white light to green light, the examinee is judged to have heterophoria. The strabismus of heterophoria is the angle of rotation of the midline of the pupil of the right eye in the process of switching from white light to red light. The angle of heterophoria can be changed into a triangular prism.

Or the white light of the equipment is turned off, and the red light is turned on at the same time, so that the examinee can keep watching the sighting target lamp. If the pupillary midline of both eyes of the examinee does not move in the process of switching from white light to red light, judging that no heterophoria exists; if the middle line of the pupil of the right eye of the examinee does not move and the middle line of the pupil of the left eye moves in the process of switching from the white light to the red light, the examinee is judged to have heterophoria, and the strabismus degree of the heterophoria is the angle of rotation of the middle line of the pupil of the left eye in the process of switching from the white light to the red light. The angle of heterophoria can also be converted into a triangular prism.

EXAMPLE seven

The apparatus disclosed in this embodiment is a head-mounted device, for example, a spectacle-type device. The left glasses frame is provided with two micro cameras and two near infrared light sources to shoot the left eyes, and the right glasses frame is provided with two micro cameras and two near infrared light sources to shoot the right eyes to form an image shooting and processing module. In this embodiment, the optotype is a printed fixed-position pattern. The headset can measure the three-dimensional position of the optotype in real time, so that the relative positions of the headset and the optotype in three-dimensional space are known.

The image processing algorithm of the image shooting and processing module, the pupil midline calculation module and the strabismus measurement module are programs running on a computer or an embedded system.

Let the examinee watch the optotypes with both eyes, which is introduced by the first embodimentThe binocular camera measuring method can measure the pupil center line of the left eye through the two miniature cameras and the two near-infrared light sources on the left eye frame, and calculate to obtain the ray P_lThe equation of U; because the head-mounted equipment can measure the three-dimensional position of the target, the ray P can be obtained by calculation_lC equation; by ray P_lU and ray P_lC can obtain the alpha. Similarly, the pupil center line of the right eye can be measured through the two micro cameras and the two near-infrared light sources on the right glasses frame, and the ray P is obtained through calculation_rThe equation of V; because the head-mounted equipment can measure the three-dimensional position of the target, the ray P can be obtained by calculation_rC equation; by ray P_rV and ray P_rC can obtain < beta >. And if the sizes of the alpha and the beta are not equal, judging that the strabismus exists.

Whether squinting exists can also be judged by comparing the directions of the alpha and the beta and the projection sizes of different planes of the head three-dimensional coordinate system. The middle point of the head-mounted device is taken as the original point of the head three-dimensional coordinate system, the direction of the original point pointing to the left side of the head-mounted device is the direction of the X axis of the head three-dimensional coordinate system, the direction of the original point pointing to the upper side of the head-mounted device is the direction of the Y axis of the head three-dimensional coordinate system, and the direction of the original point perpendicular to the XY plane and pointing to the right front side of the head-mounted device is the direction of the Z.

Setting the projection of the & alpha on the XZ plane as & theta₁The projection of the angle alpha on the YZ plane is

Setting the projection of the & lt beta on the XZ plane as & lt theta₂The projection of the angle beta on the YZ plane is

If theta₁Sum theta₂Not in the opposite direction, or

And

if the directions are not the same, the squinting is judged to be present.

In addition, the projection size and direction of ≤ α and ≤ β on XZ plane and YZ plane can be simultaneously compared. If theta₁Sum theta₂Not of equal size but of opposite direction, or

And

The strabismus measurement module can also judge which eyes strabismus. The doctor can let the person of being examined look at the sighting mark with two eyes earlier, then shelter from arbitrary one eye with the eye shield that does not pass through visible light, then observe whether the eye that does not shelter from in addition takes place to remove, judges. For example, the examinee is allowed to watch the optotype with both eyes, then the left eye is shielded, so that only the right eye can see the optotype, and if the right eye moves at the moment, the right eye is indicated as the strabismus eye; if the right eye does not move, the left eye is shown as an oblique eye. If the right eye is blocked, only the left eye can see the sighting mark, and if the left eye moves at the moment, the left eye is the oblique eye; if the left eye does not move, the right eye is shown as an oblique eye. Except that the doctor observes whether the unshielded eyes move or not by naked eyes, the image shooting and processing module of the equipment can be used for judging whether the pupil centers of the unshielded eyes move or not, or the pupil center line calculating module is used for judging whether the pupil center lines of the unshielded eyes move or not.

The apparatus may further comprise a heterophoria measurement module. And if the strabismus measuring module does not measure that the examined person has strabismus, operating the strabismus measuring module. The method comprises the steps that any one eye is shielded by an eye shielding plate which cannot transmit visible light, the image shooting and processing module detects the pupil central lines of two eyes of a detected person in real time, if the pupil central lines of the eyes which are not shielded do not move in the shielding process, and the pupil central lines of the eyes which are shielded move, the detected person is judged to have the heterophoria. The strabismus degree of heterophoria is the angle of rotation of the midline of the pupil of the eye to be shielded during the shielding process. The angle of heterophoria can also be converted into a triangular prism.

In addition, the head-mounted device may be a Virtual Reality (VR), Augmented Reality (AR), or the like.

Claims

1. An strabismus inspection apparatus, comprising:

visual target;

the strabismus measurement module is used for enabling the visual targets to be visible for the two eyes of the examinee and enabling the examinee to watch the visual targets; let the left eye pupil center P_lAs a starting point, the ray pointing to the external direction of the eyeball along the middle line of the pupil of the left eye is P_lU; let the left eye pupil center P_lAs a starting point, the ray pointing to the direction of the position C of the sighting mark is P_lC; defining ≈ α as: at the center P of the left eye pupil_lAs a vertex, with a ray P_lU as the starting edge, with ray P_lC is the angle of the terminal edge; let the center P of the right eye pupil_rAs a starting point, the ray pointing in the direction outside the eyeball along the center line of the pupil of the right eye is P_rV; let the center P of the right eye pupil_rAs a starting point, a ray pointing to the direction of C where the sighting mark is locatedLine is P_rC; defining ≈ β as: with the center P of the right eye pupil_rAs a vertex, with a ray P_rV is the starting edge, with ray P_rC is the angle of the terminal edge; after the dominant strabismus measuring module calculates and obtains the alpha and beta, if the sizes of the alpha and beta are not equal, the dominant strabismus measuring module judges that dominant strabismus exists.

2. The strabismus inspection apparatus according to claim 1, further comprising a head three-dimensional coordinate system measuring module for establishing a head three-dimensional coordinate system by identifying the feature points of the head and calculating the three-dimensional spatial coordinates of the feature points, wherein the X coordinate axis is the head left-right direction, the Y coordinate axis is the head up-down direction, the Z coordinate axis is the head front-back direction, and the origin is at any point of the head left-right symmetric plane;

The measuring module for displaying squint compares &₁Sum theta₂Direction of or comparison with

And

And

3. The strabismus inspection apparatus according to claim 1, further comprising a head three-dimensional coordinate system measuring module for establishing a head three-dimensional coordinate system by identifying the feature points of the head and calculating the three-dimensional spatial coordinates of the feature points, wherein the X coordinate axis is the head left-right direction, the Y coordinate axis is the head up-down direction, the Z coordinate axis is the head front-back direction, and the origin is at any point of the head left-right symmetric plane;

And

if theta₁Sum theta₂Not of equal size but of opposite direction, or if

And

4. The strabismus inspection device of claim 1, further comprising a head bilateral symmetry plane measurement module for measuring a three dimensional plane equation of the head bilateral symmetry plane;

Is arranged to pass through the center P of the right eye pupil_rAnd a line perpendicular to the bilateral symmetry plane of the head intersects the bilateral symmetry plane of the head at W_rPoint, then straight line P_r-W_rTo pass through the pupil center P of the right eye_rAnd point W_rIs a straight line P_r-W_rA plane is determined by the central line of the pupil of the right eye and is defined as a right plane, and the right plane is obtained by the strabismus measurement module; definition of [ theta ]_rComprises the following steps: with the center P of the right eye pupil_rAs a vertex, with a ray P_rV is the starting edge, with ray P_rC projection on right plane is angle of terminal edge, and perspective is shownQuantity module obtains angle theta_r(ii) a Definition of

The measuring module for displaying squint compares &_lSum theta_rOr comparing

And

if theta_lSum theta_rNot in the opposite direction, or if

And

5. The strabismus inspection apparatus of claim 1, further comprising a head bilateral symmetry plane measurement module capable of measuring a three-dimensional plane equation of the head bilateral symmetry plane;

The measuring module for displaying squint compares &_lSum theta_rOr comparing

And

if theta_lSum theta_rNot of equal size but opposite in direction, or if

And

6. An apparatus according to any one of claims 1 to 5, wherein the strabismus measurement module is further configured to determine the strabismus: setting two eyes as an eye A and an eye B respectively, and enabling the eye B to see the sighting mark and the eye A to not see the sighting mark when the sighting mark is judged to be sighted by the sighting mark measuring module; in the process that the examinee changes the binocular fixation optotype into the B-eye monocular fixation optotype, if the heterophoria measuring module detects that the center line of the pupil of the B eye moves, the heterophoria measuring module judges that the B eye is the heterophoria eye; if the measuring module of the strabismus detects that the pupil center line of the pupil of the eye B does not move in the process, the measuring module of the strabismus judges that the eye A is the strabismus eye.

7. An apparatus according to claim 2, 3 or 6, wherein the strabismus measurement module is further configured to calculate a strabismus degree and a strabismus direction:

The strabismus measuring module is used for measuring the center P of the left eye pupil_lAs a center of rotation, the ray P_lU along a plane parallel to the XZ plane, according to sum∠θ₂Rotate in opposite direction to &₂Angle of the same size, resulting in ray P_lU'; then, the strabismus measuring module uses the left eye pupil center P_lThe ray P is taken as the rotation center_lU' along a plane parallel to the YZ plane, according to the sum

Rotate in the same direction as

Rotate in the same direction as

Angle of the same size, resulting in ray P_rV'; what is needed isThe measuring module for the strabismus obtains the center P of the pupil of the right eye_rAs a vertex, with a ray P_rV' is the starting edge, with ray P_rAnd C is the angle of the final edge, namely the squint angle, the size of the squint angle is the squint degree, and the direction of the squint angle is the squint direction.

8. The strabismus inspection device of claim 2 or 3, wherein the strabismus measurement module is further configured to calculate strabismus;

Rotate in the same direction as

or, the projection of the & lt alpha on the XZ plane in the head three-dimensional coordinate system is & lt theta₁The component of YZ plane in the three-dimensional coordinate system of the head is

Rotate in the same direction as

9. An apparatus according to claim 4, 5 or 6, wherein the strabismus measurement module is further configured to calculate a strabismus degree and a strabismus direction;

Rotate in the same direction as

Rotate in the same direction as

10. An apparatus according to claim 4 or 5, wherein the strabismus measurement module is further configured to calculate a strabismus degree;

the strabismus measuring module is used for measuring rays P_lU is according to sum theta along the left plane_rRotate in opposite direction to &_rAngle of the same size, resulting in ray P_lU₁(ii) a Then, the strabismus measuring module is used for measuring the center of the left eye pupilP_lThe ray P is taken as the rotation center_lU₁In a direction perpendicular to the left plane according to the sum

Rotate in the same direction as

or the strabismus measurement module measures the ray P_rV is according to sum theta along the left plane_lRotate in opposite direction to &_lAngle of the same size, resulting in ray P_rV₁(ii) a Then, the measuring module for the strabismus uses the center P of the right eye pupil_rThe ray P is taken as the rotation center_rV₁In a direction perpendicular to the right plane according to the sum

Rotate in the same direction as

11. The strabismus inspection device of any one of claims 1 to 10,

the position of the sighting mark is fixed;

12. An apparatus according to any one of claims 1 to 10, further comprising a display module capable of displaying the optotype, the position at which the optotype is displayed being fixed, the display module being switched between three display modes:

13. The strabismus inspection apparatus of claim 12, wherein the display module is a display device capable of displaying visible light of two different wavelengths, or a naked eye 3D display device, or a polarization display device, or a shutter display device.

14. An apparatus according to any one of claims 1 to 10, wherein the optotype is a light-emitting lamp.

15. An apparatus according to claim 14, wherein the optotype is a lamp capable of emitting white light;

16. An apparatus according to claim 14, wherein the optotypes are three closely spaced lamps, one of which emits white light and one of which emits light of wavelength λ₁A lamp emitting light of wavelength lambda₂Of visible light, λ₁Is not equal to lambda₂；

17. A strabismus examination device as claimed in any one of claims 1 to 16, further comprising a distance sensor for real time indication of the distance of the strabismus examination device and the subject.

18. An apparatus according to any one of claims 1 to 17, wherein the apparatus is a portable handheld apparatus; the number of the near-infrared cameras is 2, and the near-infrared cameras are symmetrically distributed on the left side and the right side of the strabismus inspection equipment; the number of the near-infrared light sources is 2, and the near-infrared light sources are symmetrically distributed on the left side and the right side of the strabismus examination.

19. The strabismus inspection device of any one of claims 1 to 17, wherein the strabismus inspection device is a portable handheld strip device, the optotype being located at a midpoint of the strabismus inspection device; the number of the near-infrared cameras is 2, the near-infrared cameras are distributed on two sides of the strabismus inspection equipment and have the same distance with the midpoint of the strabismus inspection equipment; the number of the near infrared light sources is 2, the near infrared light sources are distributed on two sides of the strabismus inspection equipment and have the same distance with the midpoint of the strabismus inspection equipment; the sighting target, the 2 near-infrared cameras and the 2 near-infrared light sources are distributed on the same straight line.

20. The strabismus inspection device of claim 1, wherein the strabismus inspection device is head-mounted, having at least two of the near infrared cameras and at least two of the near infrared lamps near the left eye, capable of capturing the left eye; the at least two near-infrared cameras and the at least two near-infrared lamps are arranged near the right eye, and the right eye can be shot; the head-mounted device can measure the relative position of the optotypes in real time.