Intermittent external strabismus quantification method

Abstract

According to the intermittent external strabismus quantification method, after sight line calibration is completed, three-dimensional unit vectors of the gazing directions of the left eye and the right eye are measured and obtained, and according to the three-dimensional unit vectors, the two-eye gathering and divergence degrees in different states are calculated and obtained; the method comprises the following steps of: obtaining a threshold reference value of the binocular coherence and divergence by presetting a binocular reference pupil distance and a reference sight distance and combining the binocular coherence and divergence in different states; constructing a fitting model through the threshold reference value, and judging whether dominant outward inclination occurs at any sight distance at different time points or not; the method comprises the following steps: presetting eye use environment parameters corresponding to each time point, and carrying out statistics to obtain dominant outer skew frequencies and skew amplitudes of each sight distance at different time points; compared with the prior art, the method has the advantages that the reference interpupillary distance, the reference sight distance and the acquired binocular divergence in different states are preset, the threshold reference value of the binocular divergence is determined, the fitting model is constructed, the eye use environment parameters are introduced, and the dominant outer skew frequency and the skew amplitude meeting the conditions are acquired through statistics.

Description

Technical Field

[0001] The present invention relates to the technical field of ophthalmology detection, and particularly to a method for quantifying intermittent exotropia. Background Art

[0002] Patients with intermittent exotropia usually show monocular outward deviation when their mental attention is not concentrated, they are fatigued, looking at a distance, or when binocular fusion is broken. Clinical symptoms such as diplopia, visual fatigue, and squinting one eye in the sun may occur. As the disease progresses, not only will there be serious damage to binocular visual function, but it may also have a serious impact on the mental health and social life of the patient.

[0003] Currently, the clinical assessment methods for intermittent exotropia mainly include quantitatively measuring the strabismus angle using the prism alternate cover test, evaluating the control ability of intermittent exotropia patients using relevant scales, and examining the binocular single vision function of patients. Among them, the results measured by the prism alternate cover test at different viewing distances are currently the main basis for judging the classification of intermittent exotropia patients, the selection of treatment plans, and the preoperative surgical design in clinical practice.

[0004] However, it should be noted that there are obvious deficiencies in the clinical application of the alternate cover test based on prisms. First, this method requires the prism to be accurately placed in front of the eyes during the examination, and has a relatively high requirement for the cooperation of the examinee; second, this method highly depends on the professional quality and practical experience of the examiner, and the examination results are highly subjective; more importantly, this method cannot reflect the eye position deviation of patients under natural living scenarios based on different light intensities and eye use distances. In addition, intermittent exotropia also has the characteristics that the strabismus angle is variable and the occurrence frequency is difficult to accurately grasp.

[0005] Therefore, providing a method that can accurately and efficiently quantify the spontaneous deviation angle and spontaneous deviation frequency of intermittent exotropia patients in different living scenarios is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for quantifying intermittent exotropia, which has clear logic, is safe, effective, reliable, and easy to operate, and can effectively improve the accuracy and efficiency of quantifying intermittent exotropia.

[0007] Based on the above purpose, the technical solution provided by the present invention is as follows: A method for quantifying intermittent exotropia, comprising the following steps: After completing the calibration of the line of sight, obtain the three-dimensional unit vectors of the fixation directions of each eye; According to the three-dimensional unit vectors of the fixation directions of each eye, obtain the binocular convergence and divergence in different states; Preset the binocular reference interpupillary distance and reference viewing distance, and obtain the binocular convergence threshold reference value according to the binocular convergence in different states, the binocular reference interpupillary distance and the reference viewing distance; Determine whether there is manifest exotropia at any viewing distance at different time points according to the fitting model constructed based on the binocular convergence threshold reference value; Preset the eye use environment parameters for each time point, and obtain the manifest exotropia frequency and the magnitude of the deviation at each viewing distance at different time points according to the eye use environment parameters for each time point.

[0008] Preferably, the three-dimensional unit vector of the fixation direction of each eye is specifically: ; , where X is the horizontal direction, Y is the vertical direction, Z is the fixation depth, R is the right eye, and L is the left eye.

[0009] Preferably, the obtaining of the binocular convergence in different states according to the three-dimensional unit vector of the fixation direction of each eye includes the following steps: Calculate and obtain the horizontal eye position of the left eye and the horizontal eye position of the right eye at each time point according to a preset formula; Calculate and obtain the binocular convergence in different states according to the horizontal eye position of the left eye and the horizontal eye position of the right eye; The binocular convergence in different states includes: normal eye position convergence and manifest deviation eye position convergence.

[0010] Preferably, the preset formula is: ; , where is defined as the left eye adducting and the right eye abducting, is defined as the left eye abducting and the right eye adducting; The formula for calculating and obtaining the convergence between the left eye and the right eye is specifically: ; where is the convergence between the left eye and the right eye.

[0011] Preferably, the presetting of the binocular reference interpupillary distance and the reference viewing distance, and the obtaining of the binocular convergence threshold reference value according to the binocular convergence in different states, the binocular reference interpupillary distance and the reference viewing distance include the following steps: Obtain the theoretical value of the normal eye position convergence according to the binocular reference interpupillary distance and the reference viewing distance; Introduce a regression parameter to adjust the theoretical value of the normal eye position convergence divergence to obtain a reference value for the normal eye position convergence divergence; Obtain the reference values of the manifest deviation eye position convergence divergence at different viewing distances, and obtain the reference value of the binocular convergence divergence threshold according to the reference value of the normal eye position convergence divergence and the reference values of the manifest deviation eye position convergence divergence at different viewing distances.

[0012] Preferably, the formula for the theoretical value of the normal eye position convergence divergence is: ) ; Wherein, is the theoretical value of the normal eye position convergence divergence, is the binocular reference pupil distance, is the reference viewing distance; The formula for the reference value of the normal eye position convergence divergence is: ; Wherein, is the reference value of the normal eye position convergence divergence at the viewing distance of d, and are both regression parameters.

[0013] Preferably, the step of obtaining the reference values of the manifest deviation eye position convergence divergence at different viewing distances, and obtaining the reference value of the binocular convergence divergence threshold according to the reference value of the normal eye position convergence divergence and the reference values of the manifest deviation eye position convergence divergence at different viewing distances includes the following steps: Obtain the reference values of the manifest deviation eye position convergence divergence at the first viewing distance and the second viewing distance; Obtain the first deviation amplitude and the second deviation amplitude according to the reference value of the normal eye position convergence divergence and the reference values of the manifest deviation eye position convergence divergence at the first viewing distance and the second viewing distance; Compare the magnitudes of the first deviation amplitude and the second deviation amplitude, and select the minimum deviation amplitude; Obtain the reference value of the binocular convergence divergence threshold according to the minimum deviation amplitude and the reference value of the normal eye position convergence divergence.

[0014] Preferably, the formulas for obtaining the first deviation amplitude and the second deviation amplitude are: ; ; Wherein, and are the first tilt amplitude and the second tilt amplitude respectively, and are the reference values of the normal eye position convergence divergence at the first viewing distance and the second viewing distance respectively, and The reference values of the convergence and divergence of the manifest deviation eye position at the first viewing distance and the second viewing distance respectively; The formula for obtaining the reference value of the binocular convergence and divergence threshold is: ; Wherein, is the reference value of the binocular convergence and divergence threshold, is the reference value of the normal eye position convergence and divergence at the viewing distance of d, is the minimum value of the deviation amplitude among the first tilt amplitude and the second tilt amplitude.

[0015] Preferably, the fitting model constructed according to the reference value of the binocular convergence and divergence threshold to determine whether there is manifest exotropia at any viewing distance at different time points includes the following steps: Set the model parameters of the fitting model according to the reference value of the binocular convergence and divergence threshold, and construct a single-peak Gaussian curve fitting model and a double-peak Gaussian curve fitting model respectively; Determine the optimal curve fitting model according to the preset fitting evaluation index; When the double-peak Gaussian curve fitting model is the best, it is defined that there is manifest exotropia at any viewing distance at different time points; When the single-peak Gaussian curve fitting model is the best, it is defined that there is no manifest exotropia at any viewing distance at different time points.

[0016] Preferably, the formula of the single-peak Gaussian curve fitting model is: ; ; Wherein, , , are all model parameters of the fitting model, is the reference value of the binocular convergence and divergence threshold; The formula of the double-peak Gaussian curve fitting model is: ; ; Wherein, , , , , , are all model parameters of the fitting model, is the reference value of the binocular convergence and divergence threshold.

[0017] The intermittent exotropia quantification method provided by the present invention measures and obtains the three-dimensional unit vectors of the fixation directions of the left and right eyes after completing the line-of-sight calibration, and calculates the binocular convergence and divergence degrees in different states based on these three-dimensional unit vectors; by presetting the binocular reference pupil distance and reference viewing distance, and combining the binocular convergence and divergence degrees in different states, a reference value of the binocular convergence and divergence threshold is obtained; a fitting model is constructed through this threshold reference value to determine whether there is manifest exotropia at any viewing distance at different time points; by presetting the eye use environment parameters corresponding to each time point, the frequency of manifest exotropia and the magnitude of the deviation amplitude at each viewing distance at different time points are statistically obtained.

[0018] Compared with the prior art, this method determines the reference value of the binocular convergence and divergence threshold by presetting the reference pupil distance and reference viewing distance and the obtained binocular convergence and divergence degrees in different states, constructs a fitting model, introduces the eye use environment parameters, and statistically obtains the frequency of manifest exotropia and the magnitude of the deviation amplitude under the qualified conditions. Brief Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 It is a flowchart of an intermittent exotropia quantification method provided by an embodiment of the present invention; Figure 2 It is a flowchart of step S2 provided by an embodiment of the present invention; Figure 3 It is a flowchart of step S3 provided by an embodiment of the present invention; Figure 4 It is a flowchart of step B3 provided by an embodiment of the present invention; Figure 5 It is a flowchart of step S4 provided by an embodiment of the present invention; Figure 6 It is a convergence angle-time frequency distribution diagram in the free activity state provided by an embodiment of the present invention; Figure 7 It is a schematic diagram of the Gaussian fitting model provided by an embodiment of the present invention. Detailed Description of the Embodiments

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] The embodiments of the present invention are written in a progressive manner.

[0023] The embodiments of the present invention provide a method for quantifying intermittent exotropia at any viewing distance. It mainly solves the technical problems in the prior art, such as the difficulty in monitoring the full-time scenario and the full range during the quantification of intermittent exotropia, as well as the low accuracy and efficiency.

[0024] As Figure 1 shown, a method for quantifying intermittent exotropia includes the following steps: A method for quantifying intermittent exotropia includes the following steps: S1. After completing the line-of-sight calibration, obtain the three-dimensional unit vectors of the fixation directions of each eye. S2. According to the three-dimensional unit vectors of the fixation directions of each eye, obtain the binocular vergences in different states. S3. Preset the binocular reference interpupillary distance and reference viewing distance, and obtain the reference value of the binocular vergence threshold according to the binocular vergences, binocular reference interpupillary distance and reference viewing distance in different states. S4. Determine whether there is manifest exotropia at any viewing distance at different time points according to the fitting model constructed based on the reference value of the binocular vergence threshold. S5. Preset the eye use environment parameters for each time point, and obtain the manifest exotropia frequency and deviation amplitude size at each viewing distance at different time points according to the eye use environment parameters for each time point.

[0025] In step S1, after the staff completes the line-of-sight calibration using a wearable eye tracker when the subject is in a state without manifest exotropia, obtain the three-dimensional unit vectors of the fixation directions of each eye. In this embodiment, the specific process of obtaining the three-dimensional unit vectors of the fixation directions of each eye is as follows: Let the subject fixate on visual targets in multiple specific directions while keeping the head still, collect the corneal and pupil reflection characteristics corresponding to each specific fixation direction, and combine the principle of pupil-corneal tracking method and the method of image processing to obtain the mapping relationship between the corneal and pupil reflection characteristics and the fixation direction. Combine the corneal and pupil reflection characteristics in each frame of the real-time collected image to obtain the three-dimensional unit vectors of the fixation directions of each eye. In step S2, the vergence between the left and right eyes in different states is calculated based on the three-dimensional unit vectors of the gaze directions of each eye, that is, the difference in horizontal eye positions. In step S3, by presetting a reference interpupillary distance and a reference viewing distance, and combining the binocular vergence in different states, a reference value of the binocular vergence threshold is calculated and obtained. In step S4, a fitting model is constructed through the reference value of the binocular vergence threshold to determine whether there is monocular manifest exotropia at any viewing distance at different time points. In step S5, the eye use environment parameters at each time point are set in advance, and the manifest exotropia frequency and the magnitude of the deviation amplitude at each viewing distance at different time points are statistically obtained. In this embodiment, the eye use environment is classified with the viewing distance (d: near distance 50 cm, medium distance 50 - 600 cm, far distance > 600 cm) and the ambient light intensity (l: low light intensity 0 - 500 lux, high light intensity > 500 lux) as elements; it is mainly divided into six categories: near viewing distance (d1) + low light intensity (l1), near viewing distance (d1) + high light intensity (l2), medium viewing distance (d2) + low light intensity (l1), medium viewing distance (d2) + high light intensity (l2), far viewing distance (d3) + low light intensity (l1), far viewing distance (d3) + high light intensity (l2)); according to the classification of the eye use environment to which each time point belongs, the time-frequency distribution diagrams of the vergence angle under different conditions are respectively statistically obtained, and finally the manifest exotropia occurrence frequency and the magnitude of the deviation amplitude at any light intensity and viewing distance can be obtained.

[0026] Preferably, the three-dimensional unit vectors of the gaze directions of each eye are specifically: ; , where X is the horizontal direction, Y is the vertical direction, Z is the gaze depth, R is the right eye, and L is the left eye.

[0027] In the actual application process, the gaze directions of the left and right eyes are represented by the three-dimensional unit vectors formed with the left eye in terms of direction.

[0028] Such as Figure 2 shown, preferably, step S2 includes the following steps: A1. Calculate and obtain the horizontal eye position of the left eye and the horizontal eye position of the right eye at each time point according to a preset formula. A2. Calculate and obtain the binocular vergence in different states according to the horizontal eye position of the left eye and the horizontal eye position of the right eye. The binocular vergence in different states includes: the vergence at the normal eye position and the vergence at the manifest deviation eye position.

[0029] Preferably, the preset formula is: ; , in, Defined as left eye turning inward and right eye turning outward, It was defined as left eye abduction and right eye endoversion; The formula for calculating the vergence between the left eye and the right eye is: ; in, is the vergence between the left and right eyes.

[0030] In steps A1 and A2, the horizontal eye position of the left eye and the horizontal eye position of the right eye are calculated through the horizontal direction of the left eye and the right eye and the gaze depth (the vertical distance between the eyeball and the gaze object). After obtaining the horizontal eye position of the left eye and the right eye, the difference between the horizontal eye positions of the left eye and the right eye is calculated, which is the binocular vergence. Further calculation is made for the vergence of the eye position when in a normal state and the vergence of the eye position when a manifest deviation state occurs.

[0031] like Figure 3 As shown, preferably, step S3 includes the following steps: B1. Obtain the theoretical value of normal eye position vergence based on the reference pupil distance and reference visual distance of both eyes; B2. Introduce regression parameters to adjust the theoretical value of normal eye position vergence to obtain the reference value of normal eye position vergence; B3. Obtain reference values ​​of vergence of manifest deviation eyes at different viewing distances, and obtain reference values ​​of binocular vergence thresholds based on the reference values ​​of normal eye vergence and the reference values ​​of manifest deviation eyes at different viewing distances.

[0032] In steps B1 to B3, the reference pupil distance of both eyes is preset as PD, the reference visual distance is d, and when defining the orthotropia of both eyes (O, orthotropia), the theoretical value of the normal eye position convergence is When monocular exotropia occurs, the reference value of the manifest deviation eye position convergence is Due to factors such as instrument errors and individual differences of the subjects, the actual eye position measurement value will usually deviate from the theoretical value. Therefore, the regression parameter , Get the theoretical value of normal eye position vergence and get the reference value of normal eye position vergence ; According to the reference value of normal eye position vergence and the reference value of manifest deviation eye position vergence at different viewing distances, the reference value of binocular vergence threshold is calculated .

[0033] In this embodiment, the line of sight ( ) is 40cm, and 600cm corresponds to the vergence when both eyes are in the right position , , thus fitting the parameters β1 and β 0 value, and then the reference value of the convergence and divergence of any viewing distance of the subject can be obtained through calculation at .

[0034] Preferably, the formula for the theoretical value of the convergence and divergence of the normal eye position is: ) ; wherein, is the theoretical value of the convergence and divergence of the normal eye position, is the binocular reference pupillary distance, is the reference viewing distance; The formula for the reference value of the convergence and divergence of the normal eye position is: ; wherein, is the reference value of the convergence and divergence of the normal eye position at the viewing distance d, and are both regression parameters.

[0035] As Figure 4 shown, preferably, step B3 includes the following steps: C1. Obtain the reference values of the manifest deviation eye position convergence and divergence at the first viewing distance and the second viewing distance; C2. Obtain the first deviation amplitude and the second deviation amplitude according to the reference value of the normal eye position convergence and divergence and the reference values of the manifest deviation eye position convergence and divergence at the first viewing distance and the second viewing distance; C3. Compare the magnitudes of the first deviation amplitude and the second deviation amplitude, and select the minimum deviation amplitude; C4. Obtain the reference value of the binocular convergence and divergence threshold according to the minimum deviation amplitude and the reference value of the normal eye position convergence and divergence.

[0036] In steps C1 to C4, the reference values of the manifest deviation eye position convergence and divergence are obtained through a quantization device at the preset first viewing distance and the second viewing distance, combined with the reference value of the normal eye position convergence and divergence, and the deviation amplitude formula, to obtain the first deviation amplitude and the second deviation amplitude; compare the magnitudes of the first deviation amplitude and the second deviation amplitude, and select the minimum deviation amplitude; combine with the reference value of the normal eye position convergence and divergence to obtain the reference value of the binocular convergence and divergence threshold.

[0037] In this embodiment, by alternately covering one eye, the binocular convergence and divergence () corresponding to the eye position manifest deviation when the viewing distances are 40 cm and 600 cm are measured respectively . . Subsequently, and are obtained, and the minimum value of the two is taken as This value represents the minimum amount of deviation amplitude at the near and far viewing distances. Any value greater than this can be determined as a deviation occurring.

[0038] Preferably, the formulas for obtaining the first deviation amplitude and the second deviation amplitude are: ; ; where, and are the first tilt amplitude and the second tilt amplitude respectively, and are the reference values of normal eye position convergence and divergence at the first viewing distance and the second viewing distance respectively, and are the reference values of manifest deviation eye position convergence and divergence at the first viewing distance and the second viewing distance respectively; The formula for obtaining the reference value of the binocular convergence and divergence threshold is: ; where, is the reference value of the binocular convergence and divergence threshold, is the minimum value of the deviation amplitude among the first tilt amplitude and the second tilt amplitude.

[0039] As Figure 5 shown, preferably, step S4 includes the following steps: D1. Set the model parameters of the fitting model according to the reference value of the binocular convergence and divergence threshold, and construct a single-peak Gaussian curve fitting model and a double-peak Gaussian curve fitting model respectively; D2. Determine the optimal curve fitting model according to the preset fitting evaluation index; D31. When the double-peak Gaussian curve fitting model is optimal, it is defined that there is a manifest exotropia at any viewing distance at different time points; D32. When the single-peak Gaussian curve fitting model is optimal, it is defined that there is no manifest exotropia at any viewing distance at different time points.

[0040] In steps D1 to D31, the model parameters of the fitting model are set through the reference value of the binocular convergence and divergence threshold, the convergence and divergence of the eye position at any viewing distance are statistically counted time point frequency distribution, and the single-peak and double-peak Gaussian curve fittings are respectively performed on the formed eye position convergence and divergence time point frequency distribution diagrams, and the fitting evaluation index - corrected determination coefficient of the two fitting curves is compared; the optimal fitting curve is selected according to this index. When the double-peak Gaussian is optimal, it indicates a manifest exotropia, and vice versa, it indicates no spontaneous exotropia; ; ; in, represents the sample size, represents the number of parameters in the model, Representative Observations, The model predicts values, is the mean of the observations.

[0041] Furthermore, the incidence of exotropia is defined as If manifest exotropia occurs: ; If this does not happen,

[0042] The size of the binocular convergence angle when spontaneous deviation occurs is recorded as ; and we can also get the skew amplitude .

[0043] Preferably, the formula of the unimodal Gaussian curve fitting model is: ; ; in, , , are the model parameters of the fitted model, is the binocular convergence threshold reference value; The formula for the bimodal Gaussian curve fitting model is: ; ; in, , , , , , are the model parameters of the fitted model, is the reference value of binocular convergence threshold.

[0044] Furthermore, the present invention also provides a specific example to verify the effect of the present method, as follows: A patient with intermittent exotropia was recruited from a hospital. In addition to intermittent exotropia and refractive errors, other eye diseases and systemic diseases, the patient's eye control score was 2 points (Newcastle Control Score, NCS), and the results of the prism alternating cover measurement were: 40cm: -2 △ , 6m: -20 △; The eye movement data of both eyes in the frontal position (30 s), monocular occlusion (30 s), and free movement state (20 min) were collected using a certain wearable eye tracker in the environments of (d1 + l1) and (d3 + l1) respectively. The sampling frequency of the eye tracker was set at 60 Hz. According to the above method for calculating the interocular convergence divergence, the obtained convergence divergence angle-time frequency distribution graph of the patient in the free movement state is as Figure 6 shown; After performing single-peak and double-peak Gaussian fitting on the obtained convergence divergence-time point frequency distribution graph respectively and comparing the goodness of fit, the Gaussian fitting model is as Figure 7 shown; where the abscissa is the binocular convergence divergence ( ), the ordinate is the occurrence frequency corresponding to each convergence divergence, and the area under the curve within the range of its convergence divergence [-∞, is the total duration of manifest exotropia occurring during this examination period. The percentage of the area under this curve in the total area is the incidence rate of manifest exotropia during this examination period It is known that is 6.60°, is 1.09°. Combining with the Gaussian fitting model, it can be judged that there is no deviation in near vision indoors (d1 + l1), and manifest exotropia occurs in far vision indoors (d3 + l1). The deviation occurrence frequency ( ) is 65.86%; the deviation angle size ( ) during spontaneous deviation is -15.95°; the deviation amplitude during deviation is 18.10°.

[0045] In the embodiments provided in the present application, it should be understood that the disclosed method can be implemented in other ways. The system embodiments described above are only illustrative. For example, the division of modules is only a logical function division. In actual implementation, there can be other division methods, such as: multiple modules or components can be combined, or can be integrated into another system, or some features can be ignored, or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, and can be electrical, mechanical, or other forms.

[0046] In addition, in each embodiment of the present invention, each functional module can be all integrated in one processor, or each module can be separately used as a device alone, or two or more modules can be integrated in one device; each functional module in each embodiment of the present invention can be implemented in the form of hardware, or in the form of a combination of hardware and software functional units.

[0047] Those of ordinary skill in the art will understand that all or part of the steps of implementing the above method embodiments can be completed by program instructions and related hardware. The foregoing program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, they perform the steps including the above method embodiments; and the foregoing storage medium includes: various media such as removable storage devices, read-only memory (ROM), magnetic disks, or optical discs that can store program codes.

[0048] As shown in this application and the claims, unless the context clearly indicates an exception, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. A method or device may also include other steps or elements. An element defined by the statement "comprising one..." does not exclude the existence of another identical element in the process, method, article, or device that includes the element.

[0049] If a flowchart is used in this application, the flowchart is used to illustrate the operations performed by the system according to the embodiments of this application. It should be understood that the operations before or after may not necessarily be executed precisely in sequence. On the contrary, they can be executed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or several operations can be removed from these processes.

[0050] The above has introduced in detail a method for quantifying intermittent exotropia provided by the present invention. The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for quantifying intermittent exotropia, characterized in that: The steps include: After completing the sight line calibration, obtain the three-dimensional unit vector of each eye's gaze direction; Obtain binocular vergence in different states according to the three-dimensional unit vector of the gaze direction of each eye; Preset a binocular reference pupil distance and a reference visual distance, and obtain a binocular vergence threshold reference value according to the binocular vergence in different states, the binocular reference pupil distance and the reference visual distance; Determining whether there is explicit exotropia at any viewing distance at different time points according to the fitting model constructed by the binocular convergence threshold reference value; The eye environment parameters at each time point are preset, and the explicit exotropia frequency and the deflection amplitude at each viewing distance at different time points are obtained according to the eye environment parameters at each time point.

2. The intermittent exotropia quantification method according to claim 1, characterized in that: The three-dimensional unit vector of the gaze direction of each eye is specifically: ； ， Among them, X is the horizontal direction, Y is the vertical direction, Z is the gaze depth, R is the right eye, and L is the left eye.

3. The intermittent exotropia quantification method according to claim 1, characterized in that: The step of obtaining binocular convergence in different states according to the three-dimensional unit vector of the gaze direction of each eye comprises the following steps: Calculate and obtain the horizontal eye position of the left eye and the horizontal eye position of the right eye at each time point according to a preset formula; Calculating and acquiring binocular convergence in different states according to the left eye horizontal eye position and the right eye horizontal eye position; The binocular vergence in different states includes: normal eye position vergence and manifest deviation eye position vergence.

4. The intermittent exotropia quantification method according to claim 3, characterized in that: The preset formula is: ； ， in, Defined as left eye inward and right eye outward, It was defined as left eye abduction and right eye endoversion; The formula for calculating the vergence between the left eye and the right eye is specifically: ； in, is the vergence between the left and right eyes.

5. The intermittent exotropia quantification method according to claim 4, characterized in that: The preset binocular reference pupil distance and reference visual distance, and obtaining a binocular vergence threshold reference value according to the binocular vergence in different states, the binocular reference pupil distance and reference visual distance, include the following steps: According to the binocular reference pupil distance and the reference viewing distance, obtaining the normal eye position vergence theoretical value; Introducing a regression parameter to adjust the normal eye position vergence theoretical value to obtain a normal eye position vergence reference value; Obtaining the reference value of the vergence of the manifest deviated eye position at different viewing distances, and obtaining the reference value of the binocular vergence threshold according to the reference value of the normal eye position vergence and the reference value of the manifest deviated eye position at different viewing distances.

6. The intermittent exotropia quantification method according to claim 5, characterized in that: The formula for the theoretical value of normal eye position vergence is: ) ； in, is the theoretical value of normal eye position vergence, Refer to the pupil distance for both eyes, is the reference sight distance; The formula for the reference value of normal eye position vergence is: ； in, is the reference value of normal eye position vergence at viewing distance d, and are regression parameters.

7. The intermittent exotropia quantification method according to claim 5, characterized in that: The method of obtaining the reference value of the manifest deviation eye position vergence at different viewing distances, and obtaining the binocular vergence threshold reference value according to the reference value of the normal eye position vergence and the reference value of the manifest deviation eye position vergence at different viewing distances, comprises the following steps: Obtaining reference values ​​of the manifest deviation eye position vergence at a first viewing distance and a second viewing distance; Obtaining a first deflection amplitude and a second deflection amplitude according to the normal eye position vergence reference value and the manifest deviation eye position vergence reference values ​​at the first viewing distance and the second viewing distance; Compare the first deflection amplitude and the second deflection amplitude, and select the minimum deflection amplitude; The binocular vergence threshold reference value is acquired according to the minimum deflection amplitude and the normal eye position vergence reference value.

8. The intermittent exotropia quantification method according to claim 7, characterized in that: The formula for obtaining the first deflection amplitude and the second deflection amplitude is: ； ； in, and are the first tilt amplitude and the second tilt amplitude respectively, and They are the reference values ​​of normal eye position vergence at the first and second viewing distances, respectively. and They are the reference values ​​of the manifest deviation eye position vergence at the first visual distance and the second visual distance respectively; The formula for obtaining the binocular convergence threshold reference value is: ； in, is the binocular convergence threshold reference value, is the reference value of normal eye position convergence at viewing distance d, is the minimum value of the deflection amplitude between the first tilt amplitude and the second tilt amplitude.

9. The intermittent exotropia quantification method according to claim 1, characterized in that: The fitting model constructed according to the binocular convergence threshold reference value is used to determine whether there is explicit exotropia at any viewing distance at different time points, including the following steps: The model parameters of the fitting model are set according to the binocular convergence threshold reference value, and a single-peak Gaussian curve fitting model and a double-peak Gaussian curve fitting model are constructed respectively; Determine the optimal curve fitting model according to the preset fitting evaluation index; When the bimodal Gaussian curve fitting model is optimal, it is defined that there is explicit exotropia at any viewing distance at different time points; When the single-peak Gaussian curve fitting model is optimal, it is defined that there is no explicit exotropia at any viewing distance at different time points.

10. The intermittent exotropia quantification method according to claim 9, characterized in that: The formula of the unimodal Gaussian curve fitting model is: ； ； in, , , are the model parameters of the fitted model, is the binocular convergence threshold reference value; The formula of the bimodal Gaussian curve fitting model is: ； ； in, , , , , , are the model parameters of the fitted model, is the reference value of binocular convergence threshold.

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