A Quantification Method for Intermittent Exotropia

Abstract

The present invention provides a method for quantifying intermittent exotropia. After completing gaze calibration, the three-dimensional unit vectors of the left and right eye gaze directions are measured. Based on these three-dimensional unit vectors, binocular vergence under different conditions is calculated. A reference binocular vergence threshold is obtained by presetting a reference interpupillary distance and a reference viewing distance, combined with binocular vergence under different conditions. A fitting model is constructed using this threshold to determine whether explicit exotropia occurs at any viewing distance at different time points. Furthermore, the frequency and magnitude of explicit exotropia at each viewing distance at different time points are statistically determined by presetting the corresponding eye environment parameters for each time point. Compared to existing methods, this method uses the presetting reference interpupillary distance and reference viewing distance, along with the binocular vergence under different conditions, to determine the reference binocular vergence threshold, construct a fitting model, and incorporate eye environment parameters to statistically determine the frequency and magnitude of explicit exotropia under the conditions.

Description

Technical Field

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

[0002] Patients with intermittent exotropia typically experience an outward deviation of one eye when they are distracted, fatigued, looking far away, or when binocular fusion is disrupted. Symptoms include diplopia, visual fatigue, and squinting in sunlight. As the disease progresses, binocular vision is severely impaired and can have a serious impact on the patient's mental health and social life.

[0003] Current clinical assessment methods for intermittent exotropia include quantitative measurement of strabismus angle using the alternating prism cover test, assessment of the patient's ability to control intermittent exotropia using relevant scales, and examination of the patient's binocular vision. The results of the alternating prism cover test at different viewing distances are currently the primary basis for clinical classification of intermittent exotropia patients, selection of treatment options, and preoperative surgical planning.

[0004] However, it is worth noting that the alternating cover test based on a prism has obvious shortcomings in clinical application. First, this method requires the prism to be accurately placed in front of the eyes during the examination, which requires a high degree of cooperation from the examinee; second, this method relies heavily on the examiner's professional quality and practical experience, and the examination results are highly subjective; more importantly, this method cannot reflect the patient's eye deviation in natural life scenes based on different light intensities and eye distances. In addition, intermittent exotropia is also characterized by the variability of the strabismus angle and the difficulty in accurately grasping the frequency of occurrence.

[0005] Therefore, providing a method that supports accurate and efficient quantification of the spontaneous deviation angle and spontaneous deviation frequency of patients with intermittent exotropia in different life 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 objectives, the technical solutions provided by the present invention are as follows:

[0008] A method for quantifying intermittent exotropia comprises the following steps:

[0009] After completing the gaze calibration, obtain the three-dimensional unit vector of each eye's gaze direction;

[0010] Obtain binocular vergence in different states according to the three-dimensional unit vector of the gaze direction of each eye;

[0011] Presetting a binocular reference pupil distance and a 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 the reference visual distance;

[0012] determining whether there is manifest exotropia at any viewing distance at different time points according to a fitting model constructed based on the binocular vergence threshold reference value;

[0013] The eye environment parameters at each time point are preset, and the frequency and amplitude of the explicit exotropia at each viewing distance at different time points are obtained according to the eye environment parameters at each time point.

[0014] Preferably, the three-dimensional unit vector of the gaze direction of each eye is specifically:

[0015] ;

[0016] ,

[0017] 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.

[0018] Preferably, obtaining binocular vergence in different states according to the three-dimensional unit vector of the gaze direction of each eye comprises the following steps:

[0019] Calculate the left eye horizontal position and the right eye horizontal position at each time point according to a preset formula;

[0020] Calculating binocular convergence in different states according to the left eye horizontal eye position and the right eye horizontal eye position;

[0021] The binocular vergence in different states includes: normal eye position vergence and manifest deviation eye position vergence.

[0022] Preferably, the preset formula is:

[0023] ;

[0024] ,

[0025] in, Defined as left eye turning inward and right eye turning outward, It is defined as the left eye turning outward and the right eye turning inward;

[0026] The formula for calculating the vergence between the left eye and the right eye is specifically:

[0027] ;

[0028] in, is the vergence between the left and right eyes.

[0029] Preferably, 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, comprise the following steps:

[0030] Obtaining the normal eye position vergence theoretical value according to the binocular reference pupil distance and the reference viewing distance;

[0031] Introducing a regression parameter to adjust the normal eye position vergence theoretical value to obtain a normal eye position vergence reference value;

[0032] Obtaining reference values of eye position vergence for manifest deviation at different viewing distances, and obtaining the binocular vergence threshold reference value according to the reference value of normal eye position vergence and the reference values of eye position vergence for manifest deviation at different viewing distances.

[0033] Preferably, the formula for the theoretical value of normal eye position vergence is:

[0034] ) ;

[0035] in, is the theoretical value of normal eye vergence, The reference pupil distance for both eyes, is the reference sight distance;

[0036] The formula for the reference value of normal eye position vergence is:

[0037] ;

[0038] in, is the reference value of normal eye convergence at viewing distance d, and are regression parameters.

[0039] Preferably, the step of obtaining the reference value of eye vergence for manifest deviation at different viewing distances and obtaining the binocular vergence threshold reference value according to the reference value of normal eye vergence and the reference value of eye vergence for manifest deviation at different viewing distances comprises the following steps:

[0040] Obtaining reference values of manifest eye deviation vergence at a first viewing distance and a second viewing distance;

[0041] 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;

[0042] Comparing the first deflection amplitude and the second deflection amplitude, and selecting the minimum deflection amplitude;

[0043] The binocular vergence threshold reference value is obtained according to the minimum deflection amplitude and the normal eye position vergence reference value.

[0044] Preferably, the formula for obtaining the first deflection amplitude and the second deflection amplitude is:

[0045] ;

[0046] ;

[0047] in, and are the first tilt amplitude and the second tilt amplitude respectively, and They are the reference values of normal eye position convergence at the first and second viewing distances, respectively. and They are the reference values of manifest eye deviation vergence at the first and second visual distances respectively;

[0048] The formula for obtaining the binocular convergence threshold reference value is:

[0049] ;

[0050] in, is the reference value of binocular convergence threshold, is the reference value of normal eye convergence at viewing distance d, It is the minimum value of the deflection amplitude between the first tilt amplitude and the second tilt amplitude.

[0051] Preferably, the fitting model constructed based on the binocular vergence threshold reference value is used to determine whether there is manifest exotropia at any viewing distance at different time points, comprising the following steps:

[0052] The model parameters of the fitting model were set according to the reference value of binocular convergence threshold, and a single-peak Gaussian curve fitting model and a double-peak Gaussian curve fitting model were constructed respectively;

[0053] Determine the optimal curve fitting model based on the preset fitting evaluation index;

[0054] When the bimodal Gaussian curve fitting model is optimal, it is defined as the presence of manifest exotropia at any viewing distance at different time points;

[0055] 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.

[0056] Preferably, the formula of the unimodal Gaussian curve fitting model is:

[0057] ;

[0058] ;

[0059] in, , , are the model parameters of the fitted model, is the reference value of binocular convergence threshold;

[0060] The formula of the bimodal Gaussian curve fitting model is:

[0061] ;

[0062] ;

[0063] in, , , , , , are the model parameters of the fitted model, is the reference value of binocular convergence threshold.

[0064] The intermittent exotropia quantification method provided by the present invention measures and obtains the three-dimensional unit vectors of the gaze directions of the left and right eyes after completing line of sight calibration. Based on the three-dimensional unit vectors, binocular vergence in different states is calculated. By presetting a binocular reference pupil distance and a reference viewing distance, binocular vergence threshold reference values are obtained in combination with the binocular vergence in different states. A fitting model is constructed using the threshold reference values to determine whether explicit exotropia exists at any viewing distance at different time points. By presetting the eye environment parameters corresponding to each time point, the frequency and magnitude of explicit exotropia at each viewing distance at different time points are statistically obtained.

[0065] Compared with the existing technology, this method determines the reference value of binocular vergence threshold by presetting the reference pupil distance and reference viewing distance and obtaining binocular vergence under different states, constructs a fitting model, introduces eye environment parameters, and statistically obtains the frequency and amplitude of explicit exotropia under the conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0067] Figure 1 A flowchart of a method for quantifying intermittent exotropia provided by an embodiment of the present invention;

[0068] Figure 2 A flowchart of step S2 provided in an embodiment of the present invention;

[0069] Figure 3 A flowchart of step S3 provided in an embodiment of the present invention;

[0070] Figure 4 A flowchart of step B3 provided in an embodiment of the present invention;

[0071] Figure 5 A flowchart of step S4 provided in an embodiment of the present invention;

[0072] Figure 6 A frequency distribution diagram of vergence angle-time in a free-motion state provided by an embodiment of the present invention;

[0073] Figure 7 A schematic diagram of a Gaussian fitting model provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0074] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0075] The embodiments of the present invention are written in a progressive manner.

[0076] The present invention provides a method for quantifying intermittent exotropia at any viewing distance, which primarily addresses the technical issues in the prior art of intermittent exotropia quantification, such as difficulty in full-time and full-distance monitoring, and low accuracy and efficiency.

[0077] like Figure 1 As shown, a method for quantifying intermittent exotropia comprises the following steps:

[0078] A method for quantifying intermittent exotropia comprises the following steps:

[0079] S1. After completing the gaze calibration, obtain the three-dimensional unit vector of each eye's gaze direction;

[0080] S2. Obtain binocular vergence under different states based on the three-dimensional unit vector of each eye's gaze direction;

[0081] S3 preset binocular reference pupil distance and reference viewing distance, according to the binocular vergence in different states, binocular reference pupil distance and reference viewing distance, obtain binocular vergence threshold reference value;

[0082] S4. Determine whether explicit exotropia exists at any viewing distance at different time points based on a fitting model constructed using binocular vergence threshold reference values;

[0083] S5. Preset the eye environment parameters at each time point, and obtain the frequency and amplitude of explicit exotropia at each viewing distance at different time points based on the eye environment parameters at each time point.

[0084] In step S1, the staff uses a wearable eye tracker to complete the gaze calibration of the subject without manifest exotropia, and obtains the three-dimensional unit vector of the gaze direction of each eye;

[0085] In this embodiment, the specific process of obtaining the three-dimensional unit vector of each eye's gaze direction is:

[0086] The subject is instructed to keep their head still and gaze at visual targets in multiple specific directions. The corneal and pupil reflection features corresponding to each specific gaze direction are collected. The mapping relationship between the corneal and pupil reflection features and the gaze direction is obtained by combining the principles of pupil-corneal tracking and image processing. The three-dimensional unit vector in the gaze direction of each eye is obtained by combining the corneal and pupil reflection features in each frame of the real-time image collection.

[0087] In step S2, the vergence between the left and right eyes in different states, i.e., the difference in horizontal eye position, is calculated based on the three-dimensional unit vector of each eye's gaze direction;

[0088] In step S3, a binocular vergence threshold reference value is calculated by presetting a reference pupil distance and a reference viewing distance and combining binocular vergence in different states;

[0089] In step S4, a fitting model is constructed using binocular vergence threshold reference values to determine whether monocular manifest exotropia exists at any viewing distance at different time points;

[0090] In step S5, the eye environment parameters at each time point are set in advance, and the frequency and magnitude of the apparent exotropia at each viewing distance at different time points are statistically obtained;

[0091] In this embodiment, the eye environment is classified based on viewing distance (d: near distance 50 cm, middle distance 50-600 cm, far distance > 600 cm) and ambient light intensity (l: low light intensity 0-500 lux, high light intensity > 500 lux). The classification is mainly divided into six categories: near viewing distance (d1) + low light intensity (l1), near viewing distance (d1) + high light intensity (l2), middle viewing distance (d2) + low light intensity (l1), middle viewing distance (d2) + high light intensity (l2), far viewing distance (d3) + low light intensity (l1), and far viewing distance (d3) + high light intensity (l2). According to the eye environment classification to which each time point belongs, the time frequency distribution diagram of the convergence angle under different conditions is statistically analyzed respectively, and finally the frequency of occurrence and the magnitude of the deviation of manifest exotropia under any light intensity and viewing distance can be obtained.

[0092] Preferably, the three-dimensional unit vector of the gaze direction of each eye is specifically:

[0093] ;

[0094] ,

[0095] 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.

[0096] In actual application, the direction and the left eye form a three-dimensional unit vector to represent the gaze direction of the left and right eyes.

[0097] like Figure 2 As shown, preferably, step S2 includes the following steps:

[0098] A1. Calculate 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;

[0099] A2. Calculate binocular vergence under different conditions based on the left and right eye horizontal eye positions.

[0100] Binocular vergence in different states includes normal eye position vergence and manifest deviation eye position vergence.

[0101] Preferably, the preset formula is:

[0102] ;

[0103] ,

[0104] in, Defined as left eye turning inward and right eye turning outward, It is defined as the left eye turning outward and the right eye turning inward;

[0105] The formula for calculating the vergence between the left eye and the right eye is:

[0106] ;

[0107] in, is the vergence between the left and right eyes.

[0108] In steps A1 and A2, the horizontal eye position of the left eye and the horizontal eye position of the right eye are calculated using the horizontal directions of the left eye and the right eye and the depth of gaze (the vertical distance between the eyeball and the object being gazed). After obtaining the horizontal eye position of the left eye and the horizontal eye position of 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. The vergence of the eye position when in a normal state and the vergence of the eye position when a manifest deviation occurs are further calculated.

[0109] like Figure 3 As shown, preferably, step S3 includes the following steps:

[0110] B1. Obtain the theoretical value of normal eye vergence based on the reference pupil distance and reference visual distance of both eyes;

[0111] B2. Introducing regression parameters to adjust the theoretical value of normal eye position vergence to obtain a reference value of normal eye position vergence;

[0112] B3. Obtain reference values for vergence of manifest deviation eyes at different viewing distances. Based on the reference values for vergence of normal eye position and the reference values for vergence of manifest deviation eyes at different viewing distances, obtain reference values for binocular vergence thresholds.

[0113] 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 (O, orthotropia), the theoretical value of normal eye position convergence is When monocular exotropia occurs, the reference value of the vergence of the manifest deviation eye position is Due to factors such as instrument errors and individual differences of subjects, the actual eye position values will usually deviate from the theoretical values. Therefore, the regression parameter , Get the theoretical value of normal eye position vergence and the reference value of normal eye position vergence According to the reference value of normal eye position convergence and the reference value of manifest deviation eye position convergence at different viewing distances, the reference value of binocular convergence threshold is calculated. .

[0114] In this embodiment, the viewing distance ( ) is 40cm, and 600cm corresponds to the vergence when both eyes are in the right position. , , thus fitting the parameters β 1 and β 0, and then the visual distance of the subject can be calculated Next reference value.

[0115] Preferably, the formula for the theoretical value of normal eye position vergence is:

[0116] ) ;

[0117] in, is the theoretical value of normal eye vergence, The reference pupil distance for both eyes, is the reference sight distance;

[0118] The formula for the reference value of normal eye position vergence is:

[0119] ;

[0120] in, is the reference value of normal eye convergence at viewing distance d, and are regression parameters.

[0121] like Figure 4 As shown, preferably, step B3 includes the following steps:

[0122] C1. Obtain reference values of manifest eye deviation vergence at the first and second viewing distances;

[0123] C2. Obtaining a first deviation amplitude and a second deviation amplitude based on a normal eye vergence reference value and a manifest deviation eye vergence reference value at a first viewing distance and a second viewing distance;

[0124] C3. Compare the first and second skew amplitudes and select the minimum skew amplitude;

[0125] C4. Obtain a binocular vergence threshold reference value based on the minimum deviation amplitude and the normal eye position vergence reference value.

[0126] In steps C1 to C4, a quantification device is used to obtain a reference value of the manifest deviation eye position vergence at a preset first viewing distance and a second viewing distance. The reference value of the normal eye position vergence and the deflection amplitude formula are combined to obtain a first deflection amplitude and a second deflection amplitude. The first deflection amplitude and the second deflection amplitude are compared to select the minimum deflection amplitude. The reference value of the binocular vergence threshold is obtained by combining the normal eye position vergence reference value.

[0127] In this embodiment, the viewing distance ( ) is 40cm, and the eye position deviation corresponding to 600cm is obvious ( ) , Then we get and , take the minimum of the two This value represents the minimum amount of deflection at near and far viewing distances. Any value greater than this value It can be determined that deflection has occurred.

[0128] Preferably, the formula for obtaining the first deflection amplitude and the second deflection amplitude is:

[0129] ;

[0130] ;

[0131] in, and are the first tilt amplitude and the second tilt amplitude respectively, and They are the reference values of normal eye convergence at the first and second viewing distances, and They are the reference values of manifest eye deviation vergence at the first and second visual distances respectively;

[0132] The formula for obtaining the reference value of binocular convergence threshold is:

[0133] ;

[0134] in, is the binocular convergence threshold reference value, It is the minimum value of the deflection amplitude between the first tilt amplitude and the second tilt amplitude.

[0135] like Figure 5 As shown, preferably, step S4 includes the following steps:

[0136] D1. Setting model parameters of the fitting model based on the binocular convergence threshold reference value, and constructing a unimodal Gaussian curve fitting model and a bimodal Gaussian curve fitting model respectively;

[0137] D2. Determine the optimal curve fitting model based on the preset fitting evaluation indicators;

[0138] D31. When the bimodal Gaussian curve fitting model is optimal, it is defined as the presence of manifest exotropia at any viewing distance at different time points;

[0139] D32. When the unimodal Gaussian curve fitting model is optimal, it is defined as the absence of explicit exotropia at any viewing distance at any time point.

[0140] In step D1 to step D31, the model parameters of the fitting model are set by the binocular convergence threshold reference value, and the eye position convergence at any viewing distance is counted. Time point frequency distribution, the formed eye position vergence time point frequency distribution diagram was fitted with single peak and double peak Gaussian curves, and the fitting evaluation index of the two fitting curves - the correction determination coefficient ; Based on this index, the optimal fitting curve is selected. When the bimodal Gaussian curve is optimal, it indicates the occurrence of manifest exotropia, otherwise it indicates the absence of spontaneous exotropia;

[0141] ;

[0142] ;

[0143] in, represents the number of samples, represents the number of parameters in the model, Representative observations, The model predicts values, is the mean of the observations.

[0144] Furthermore, the incidence of exotropia is defined as If manifest exotropia occurs:

[0145] ;

[0146] If this does not happen,

[0147] The size of the binocular convergence angle when spontaneous deviation occurs is recorded as ; and we can also get the skew amplitude .

[0148] Preferably, the formula of the unimodal Gaussian curve fitting model is:

[0149] ;

[0150] ;

[0151] in, , , are the model parameters of the fitted model, is the reference value of binocular convergence threshold;

[0152] The formula for the bimodal Gaussian curve fitting model is:

[0153] ;

[0154] ;

[0155] in, , , , , , are the model parameters of the fitted model, is the reference value of binocular convergence threshold.

[0156] Furthermore, the present invention also provides a specific example to verify the effect of this method, as follows:

[0157] A patient with intermittent exotropia was recruited from a hospital. In addition to intermittent exotropia and refractive error, other eye diseases and systemic diseases, the patient's eye position control score (Newcastle Control Score, NCS) was 2 points, and the results of the prism alternating cover measurement were: 40cm: -2 △ , 6m: -20 △ A wearable eye tracker was used to collect eye movement data in the (d1+l1) and (d3+l1) environments, respectively, under the conditions of binocular alignment (30s), monocular cover (30s), and free movement (20min). The sampling frequency of the eye tracker was set to 60Hz. According to the above interocular vergence calculation method, the vergence angle-time frequency distribution diagram of the patient in the free movement state was obtained as shown below. Figure 6 As shown;

[0158] The obtained vergence-time frequency distribution diagram was fitted with single-peak and double-peak Gaussian fitting respectively and the goodness of fit was compared to obtain the Gaussian fitting model as follows: Figure 7 As shown;

[0159] The horizontal axis is the binocular convergence ( ), the vertical axis is the frequency of occurrence corresponding to each vergence, and the vergence is calculated in [-∞, The area under the curve within the range of ] is the total duration of manifest exotropia during the examination period, and the percentage of the area under the curve to the total area is the incidence rate of manifest exotropia during the examination period.

[0160] Already known is 6.60°, is 1.09°. Combining with the Gaussian fitting model, it can be determined that there is no deviation in indoor near vision (d1+l1), and there is obvious exotropia in indoor far vision (d3+l1). The frequency of deviation ( ) is 65.86%; the deflection angle during spontaneous deflection ( ) is -15.95°; when the deflection occurs, the deflection amplitude is 18.10°.

[0161] In the embodiments provided in this application, it should be understood that the disclosed methods can be implemented in other ways. The system embodiments described above are merely illustrative. For example, the division of modules is merely a logical function division. In actual implementation, there may 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 components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0162] In addition, all functional modules in the embodiments of the present invention may be integrated into one processor, or each module may be a separate device, or two or more modules may be integrated into one device; the functional modules in the embodiments of the present invention may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0163] Those skilled in the art will understand that all or part of the steps of the above-mentioned method embodiment can be completed by program instructions and related hardware. The aforementioned program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, the steps of the above-mentioned method embodiment are executed; and the aforementioned storage medium includes: mobile storage devices, read-only memories (ROM), magnetic disks or optical disks, and other media that can store program codes.

[0164] As used in this application and the claims, unless the context clearly indicates an exception, the terms "a," "an," "an," and / or "the" are not intended to refer to the singular and may include the plural, unless the context clearly indicates otherwise. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements. The phrase "comprises a..." does not preclude the presence of additional identical elements in the process, method, product, or apparatus that includes the elements.

[0165] If a flow chart is used in this application, the flow chart is used to illustrate the operations performed by the system according to the embodiments of the application. It should be understood that the previous or subsequent operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. At the same time, other operations can be added to these processes, or one or more operations can be removed from these processes.

[0166] The above describes in detail a method for quantifying intermittent exotropia provided by the present invention. The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be construed in the widest possible manner 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 gaze 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; Presetting a binocular reference pupil distance and a 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 the reference visual distance; determining whether there is manifest exotropia at any viewing distance at different time points according to a fitting model constructed based on the binocular vergence threshold reference value; The eye environment parameters at each time point are preset, and the frequency and amplitude of the explicit exotropia 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, wherein: 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, wherein: The step of obtaining binocular vergence in different states according to the three-dimensional unit vector of the gaze direction of each eye comprises the following steps: Calculate the left eye horizontal position and the right eye horizontal position at each time point according to a preset formula; Calculating 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, wherein: The preset formula is: ； ， in, Defined as left eye turning inward and right eye turning outward, It is defined as the left eye turning outward and the right eye turning inward; 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, wherein: The preset binocular reference pupil distance and reference viewing distance, and obtaining a binocular vergence threshold reference value according to the binocular vergence in different states, the binocular reference pupil distance and reference viewing distance, include the following steps: Obtaining the normal eye position vergence theoretical value according to the binocular reference pupil distance and the reference viewing distance; Introducing a regression parameter to adjust the normal eye position vergence theoretical value to obtain a normal eye position vergence reference value; Obtaining reference values of eye position vergence for manifest deviation at different viewing distances, and obtaining the binocular vergence threshold reference value according to the reference value of normal eye position vergence and the reference values of eye position vergence for manifest deviation at different viewing distances.

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

7. The intermittent exotropia quantification method according to claim 5, wherein: 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 normal eye position vergence reference value and the manifest deviation eye position vergence reference value at different viewing distances, comprises the following steps: Obtaining reference values of manifest eye deviation 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; Comparing the first deflection amplitude and the second deflection amplitude, and selecting the minimum deflection amplitude; The binocular vergence threshold reference value is obtained according to the minimum deflection amplitude and the normal eye position vergence reference value.

8. The intermittent exotropia quantification method according to claim 7, wherein: The formula for obtaining the first skew amplitude and the second skew 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 convergence at the first and second viewing distances, respectively. and They are the reference values of manifest eye deviation vergence at the first and second visual distances 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 convergence at viewing distance d, It 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, wherein: The method of determining whether there is manifest exotropia at any viewing distance at different time points using a fitting model constructed based on the binocular vergence threshold reference value comprises the following steps: The model parameters of the fitting model were set according to the reference value of binocular convergence threshold, and a single-peak Gaussian curve fitting model and a double-peak Gaussian curve fitting model were constructed respectively; Determine the optimal curve fitting model based on the preset fitting evaluation index; When the bimodal Gaussian curve fitting model is optimal, it is defined as the presence of manifest 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, wherein: The formula of the unimodal Gaussian curve fitting model is: ； ； in, , , are the model parameters of the fitted model, is the reference value of binocular convergence threshold; 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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