Journal of Pediatric Ophthalmology and Strabismus

Original Article Supplemental Data

Comparison Between Parental Observations and Clinical Evaluation Findings in Korean Pediatric Patients With Intermittent Exotropia

Wonyung Son, MD; Won Jae Kim, MD

Abstract

Purpose:

To compare parental observations with the clinical evaluation findings in pediatric patients with intermittent exotropia and evaluate the clinical factors associated with the parental observations.

Methods:

This prospective study included either one or both parents of pediatric patients with intermittent exotropia who visited the clinic between January and May 2019. The parental observations were assessed through a questionnaire that included questions on the age of onset, usually deviated eye, degree of awareness, and frequency of exotropia. These findings were compared with those of the clinical evaluations, including the amount of ocular deviation and level of control.

Results:

A total of 100 parents (mean age: 39.7 years; 78 women) of 95 pediatric patients (mean age: 8.2 years; 47 girls) with intermittent exotropia participated in the study. The parental observation and clinical evaluation findings on the usually deviated eye showed good concordance (74%). The degree of parental awareness did not show any association with the amount of deviation. However, it showed a statistically significant increase associated with the worsening level of distance control (P = .04). The parental observations of the frequency of exotropia significantly increased with the worsening of the level of near (P = .037) and overall (P = .019) control.

Conclusions:

Parental observations are more likely to correlate with the level of control than with the amount of ocular deviation in pediatric patients with intermittent exotropia.

[J Pediatr Ophthalmol Strabismus. 2020;57(3):199–203.]

Abstract

Purpose:

To compare parental observations with the clinical evaluation findings in pediatric patients with intermittent exotropia and evaluate the clinical factors associated with the parental observations.

Methods:

This prospective study included either one or both parents of pediatric patients with intermittent exotropia who visited the clinic between January and May 2019. The parental observations were assessed through a questionnaire that included questions on the age of onset, usually deviated eye, degree of awareness, and frequency of exotropia. These findings were compared with those of the clinical evaluations, including the amount of ocular deviation and level of control.

Results:

A total of 100 parents (mean age: 39.7 years; 78 women) of 95 pediatric patients (mean age: 8.2 years; 47 girls) with intermittent exotropia participated in the study. The parental observation and clinical evaluation findings on the usually deviated eye showed good concordance (74%). The degree of parental awareness did not show any association with the amount of deviation. However, it showed a statistically significant increase associated with the worsening level of distance control (P = .04). The parental observations of the frequency of exotropia significantly increased with the worsening of the level of near (P = .037) and overall (P = .019) control.

Conclusions:

Parental observations are more likely to correlate with the level of control than with the amount of ocular deviation in pediatric patients with intermittent exotropia.

[J Pediatr Ophthalmol Strabismus. 2020;57(3):199–203.]

Introduction

The observational findings of parents are important for the early detection of pediatric strabismus.1 However, previous studies have demonstrated that the observational findings of parents may differ from those of clinicians in patients with strabismus.2,3 Intermittent exotropia is the most common type of strabismus among the Asian population. Previous studies on parental observations of strabismus included patients with various types of strabismus.2,4,5 There has been no study comparing the parental observations and clinical evaluation findings solely in patients with intermittent exotropia. The purpose of this study was to compare the parental observations with the clinical evaluation findings in pediatric patients with intermittent exotropia and to determine the clinical factors associated with the parental observations.

Patients and Methods

This study was performed in accordance with the tenets of the Declaration of Helsinki and was approved by the institutional review board of Yeungnam University Medical Center. The use of anonymized patient data requirement for informed consent was waived by the board. This was a prospective study in which one or both parents of pediatric patients with intermittent exotropia who first visited our clinic between January and May 2019 were enrolled. Parents of children with the basic type of exotropia, which was defined as when the difference between the distance and near angle was within 10 prism diopters (PD), were included in this study. Parents of patients with an ocular deviation of less than 18 PD, concomitant vertical deviation, prior history of strabismus surgery, or any neurological impairments were excluded. The foreign parents who could not understand the Korean questionnaire were also excluded from the study.

Parental Observations

Parental observations were assessed using a questionnaire that was developed by the authors based on the previously used scoring system of exotropia6 (Table A, available in the online version of this article). It consisted of one open-ended question and three multiple-choice questions. The questionnaire was in Korean and was provided to parents who accompanied pediatric patients at their initial visit. It included questions regarding the parental observations on the age of onset, usually deviated eye, degree of awareness, and frequency of the exotropia. The survey questionnaire was performed before clinical examinations. The parents were not assisted or instructed while completing the questionnaire.

Questionnaire for Evaluating Parental Observations of Pediatric Patients With Intermittent Exotropia

Table A:

Questionnaire for Evaluating Parental Observations of Pediatric Patients With Intermittent Exotropia

Clinical Evaluations

Clinical evaluations included the measurement of the amount of ocular deviation and the level of control. The amount of deviation was measured using an alternate prism cover test at 6-m and 33-cm fixation. The level of control was measured using the Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) control scoring system.7 This control system was constructed by incorporating scales for both distance and near evaluation (5-point scales: 0 to 4 in each), yielding a total score ranging from 0 to 8. A higher score indicated a poorer level of control. All clinical examinations were performed by one clinician (WJK). Stereoacuity measurements were performed using the Lang I test (LANG-STEREOTEST AG, Küsnacht, Switzerland) and Stereo Fly Stereotest (Stereo Optical Co., Chicago, IL) when the patient was able to cooperate and complete the test.

Statistical Analysis

We compared the parental observational findings with the clinical evaluation findings using the chi-square test and linear-by-linear association. Data were analyzed using SPSS statistical software, version 20.0 (IBM Corporation, Armonk, NY). A P value less than .05 was considered statistically significant.

Results

A total of 100 parents of 95 pediatric patients with intermittent exotropia completed the questionnaires. The basic characteristics of the included parents and pediatric patients are shown in Table 1. The mean age of the parents was 39.7 years and two-thirds of them were women. The mean age of the patients was 8.2 years (range: 2 to 15 years).

Basic Characteristics of Included Parents (n = 100) and Pediatric Patients (n = 95) With Intermittent Exotropia

Table 1:

Basic Characteristics of Included Parents (n = 100) and Pediatric Patients (n = 95) With Intermittent Exotropia

The mean amount of deviation was 27.58 PD at distance and 29.63 PD at near. The mean control score was 2.7 at distance, 1.9 at near, and 4.6 when combined. The mean age of onset of the exotropia based on the parental observations was 6 years (range: 0 to 12 years); 99 of 100 parents answered this question. The concordance rate on the usually deviated eye between the parental observation and the clinical evaluation findings was 74%.

With respect to the degree of parental awareness of the exotropia, 76 parents reported a high degree and 24 reported a low degree of awareness. The mean age of onset of the exotropia was 5.5 years (range: 0 to 12 years) in patients whose parents reported a high degree of awareness and 7.7 years (range: 2 to 12 years) in patients whose parents reported a low degree of awareness (P = .002, t test).

The mean amount of deviation showed no significant difference between the parents with a high awareness and those with a low awareness. In the comparison between the degree of parental awareness and the amount of deviation, there was no statistically significant threshold of parental awareness according to the amount of deviation (all thresholds from 25 to 45 PD, all P > .05, chi-square test). However, the patients whose parents reported a high degree of awareness had a worse level of control at distance (mean control score at distance: 2.8 for high awareness, 2.2 for low awareness, P = .039, t test). In the comparison between the degree of parental awareness and the level of control, the degree of awareness showed a statistically significant increase associated with the increase of the distance control score (Figure 1, P = .040, linear-by-linear association). It indicated that the degree of parental awareness increased with a worsening level of control at distance.

The association between the parental degree of awareness and the level of control at distance. The level of control was measured using the Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) control scoring system. Higher scores indicate poorer levels of control. The degree of awareness significantly increased with the increase of the distance control score (P = .040, linear-by-linear association). It indicated that the degree of parental awareness increased with a poorer level of control at distance.

Figure 1.

The association between the parental degree of awareness and the level of control at distance. The level of control was measured using the Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) control scoring system. Higher scores indicate poorer levels of control. The degree of awareness significantly increased with the increase of the distance control score (P = .040, linear-by-linear association). It indicated that the degree of parental awareness increased with a poorer level of control at distance.

The comparison between the parental observation of the frequency of exotropia and the level of control is presented in Figure 2. The parental observation of the frequency of exotropia significantly increased with an increasing score for near control (P = .037, linear-by-linear association). It indicated that the parental observation of the frequency of exotropia increased with a poorer level of control at near. In addition, it also increased with an increasing score for distance control; however, this correlation was not statistically significant (P = .089, linear-by-linear association). The parental observation of the frequency of exotropia increased with an increasing overall score for control (P = .019).

The association between the parental observation of the frequency of exotropia and the level of control at near, distance, and overall. The level of control was measured using the Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) control scoring system. Higher scores indicated poorer levels of control. The parental observation of the frequency of exotropia significantly increased with higher scores for near control (P = .037, linear-by-linear association). It also increased with higher scores for distance control; however, these correlations were not statistically significant (P = .089). Furthermore, the parental observation of the frequency of exotropia increased with higher scores for overall control (P = .019). This indicated that the parental observation of the frequency of exotropia increased with poorer levels of control at near and overall.

Figure 2.

The association between the parental observation of the frequency of exotropia and the level of control at near, distance, and overall. The level of control was measured using the Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) control scoring system. Higher scores indicated poorer levels of control. The parental observation of the frequency of exotropia significantly increased with higher scores for near control (P = .037, linear-by-linear association). It also increased with higher scores for distance control; however, these correlations were not statistically significant (P = .089). Furthermore, the parental observation of the frequency of exotropia increased with higher scores for overall control (P = .019). This indicated that the parental observation of the frequency of exotropia increased with poorer levels of control at near and overall.

Other factors including age at the first visit, gender, and results of stereotest did not show any association with parental observations (all factors, P > .05).

Discussion

Parents are usually the first to notice the abnormal ocular deviation in their child and may be the main observer.1,8 Previous studies showed that the parental observations of strabismus did not correspond with the clinical diagnoses.2,3 Han and Lim2 reported that the overall concordance rate between parental reports and clinical diagnoses was 67%, and that exotropia was more reliably detected by parents than esotropia. The observers' backgrounds can significantly influence their ability to detect strabismus.4,5 The Newcastle Control Score, a scoring system used to quantify the level of control on a numeric scale, has a home control score based on the parental reports.6 However, another office-based control scale excludes the parental reports of exotropia because the error in the parental observation could profoundly alter the overall score and subsequent management.9

Previous studies investigating the parental observations of strabismus included patients with different types of strabismus.2,4,5 Intermittent exotropia is the most common type of strabismus among the Asian population, particularly in Koreans. Patients with intermittent exotropia may show a variable amount of deviation and level of control in daily life; thus, the observational findings of parents can differ from those of clinicians. However, no study has ever compared the parental observations with the clinical evaluation findings solely in patients with intermittent exotropia. In addition, we compared the parental observations with both the amount of deviation and the level of control, which are the main clinical factors affecting the manifestation of exotropia, to determine which of these factors is more associated with the parental observations. The parental observations were assessed using questions with two or four simple answer options, and not using a wide range scale.

Based on the results of our study, parental observations of exotropia are more likely to correlate with the level of control than with the amount of deviation. Therefore, clinicians should be aware that the parental observations can differ from their findings according to the level of control, even in pediatric patients with a large amount of deviation.

The manifestation of intermittent exotropia is usually variable and it can be affected not only by the amount of exotropia, but also by the level of control.10,11 Previous studies have suggested a deviation of 12 to 16 PD as a threshold for detecting exotropia; however, these studies assessed the degree of awareness using photography and could not reflect the effect of the level of control on the observation.4,5 The manifestation of exotropia and parental observations can vary in daily life according to the level of control. Children with a greater amount of deviation and a good level of control can easily hide the exotropia, and parents may not easily notice it. Conversely, a small amount of exodeviation but a poor level of control may be more likely to be noticed by the parents.10

The degree of parental awareness did not significantly correlate with the amount of deviation. The mean amount of deviation showed no significant difference between the parents with a high awareness and those with a low awareness. Interestingly, patients whose parents reported a low degree of awareness had a wide range of ocular deviation, even as large as 45 PD. However, the patients whose parents reported a low level of awareness had a better level of control at distance. The observational findings of parents may differ from those of clinicians in pediatric patients with a good level of control, even in those with a large amount of deviation. Similarly, a previous study by Han and Lim2 showed that the concordance rate of parental observations was higher at greater amounts of ocular deviation (≥ 30 PD). This may be because their study included patients with different types of strabismus and because the frequency of deviation was evaluated based only on the parental observation, without a comparison with the objective clinical findings.

The parental observation of the frequency of exotropia was more associated with the level of control at near and the level of overall control scores than with that at distance; it was increased in cases with a poorer level of near and overall control. Similarly, the study by Lim et al.12 showed that poorer office-based control scores at near were correlated with poorer parental mean health-related quality of life and psychological health-related quality of life scores. It may be because patients with exotropia that is poorly controlled at near are more likely to be noticed by their parents. We postulated that parents usually have face-to-face conversations with their child. Therefore, the exotropia is more easily and more frequently noticed by the parents in patients with poor control at near.

The patients whose parents reported a high degree of awareness showed earlier onset of exotropia compared with the patients whose parents reported a low degree of awareness. These patients had a worse level of control at distance. We suspect that a worse level of control might lead to earlier onset of exotropia that would be more likely to be observed by their parents.

The current study has some limitations. First, the variability of the level of control in patients with exotropia could have affected the results of this study.13 The level of control can vary throughout the day, even within minutes. In this study, we analyzed the level of control measured at one time point, the first visit. Future studies should include the mean level of control based on measurements from several time points. Second, the interindividual difference in facial features can affect the parental observation of exotropia. The eyelid contour and position can result in a difference in the observations of strabismus, such as in the case of pseudoesotropia in infants with an epicanthic fold.14 Third, our results may not reflect the effect of ethnic background in the detection of exotropia. The ethnic background can affect the observations of strabismus.5 However, this study only included Korean parents who could understand the questionnaire in Korean.

This is the first study to compare the parental observations with the clinical evaluation findings in pediatric patients with intermittent exotropia. The parental observation and clinical evaluation findings on the usually deviated eye showed good concordance. The parental observations were more likely to correlate with the level of control than with the amount of deviation in these patients. The degree of parental awareness was correlated with the level of control at distance. The parental observation of the frequency of exotropia significantly increased with a poorer level of control at near and overall control.

References

  1. Rosner J. Parents as screeners for strabismus in their children. J Vis Impair Blind. 1988;82(5):193–194.
  2. Han KE, Lim KH. Discrepancies between parental reports and clinical diagnoses of strabismus in Korean children. J AAPOS. 2012;16(6):511–514.
  3. Kim WJ, Kim MM. Subsequent strabismus surgeries in patients with no prior medical records. Indian J Ophthalmol. 2018;66(10):1451–1455.
  4. Larson SA, Keech RV, Verdick RE. The threshold for the detection of strabismus. J AAPOS. 2003;7(6):418–422.
  5. Chan KW, Deng L, Weissberg EM. Detection of strabismus by non-health care professionals in an ethnically diverse set of images. JAMA Ophthalmol. 2016;134(1):30–36.
  6. Haggerty H, Richardson S, Hrisos S, et al. The Newcastle Control Score: a new method of grading the severity of intermittent distance exotropia. Br J Ophthalmol. 2004;88(2):233–235.
  7. Kim H, Kim DH, Ahn H, et al. Proposing a new scoring system in intermittent exotropia: towards a better assessment of control. Can J Ophthalmol. 2017;52:235–239.
  8. Lecouturier J, Clarke MP, Errington G, et al. Treating childhood intermittent distance exotropia: a qualitative study of decision making. BMC Ophthalmol. 2015;15:112. doi:10.1186/s12886-015-0087-y. [CrossRef]
  9. Mohney BG, Holmes JM. An office-based scale for assessing control in intermittent exotropia. Strabismus. 2006;14(3):147–150.
  10. Kim WJ, Kim MM. Variability of preoperative measurements in intermittent exotropia and its effect on surgical outcome. J AAPOS. 2017;21(3):210–214.
  11. Kushner BJ. Exotropia. In: Kushner BJ. Strabismus. Gewerbestrasse, Switzerland: Springer; 2017:73–95.
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  14. Wang DH, Chang JH. Relationship between cornea and lid margin position on the appearance of strabismus. Optom Vis Sci. 2015;92(7):815–822.

Basic Characteristics of Included Parents (n = 100) and Pediatric Patients (n = 95) With Intermittent Exotropia

CharacteristicValue
Parents
  Mean ± SD age (range), y39.7 ± 4.5 (28 to 50)
  Male:female22:78
Patients
  Mean ± SD age (range), y8.2 ± 2.5 (2 to 15)
  Gender (male:female)48:47
  Mean onset of exotropia (range), y6.0 ± 3.0 (0 to 12)
Clinical evaluation findings
  Amount of ocular deviation (range), PD
    Distance27.58 ± 6.68 (20 to 50)
    Near29.63 ± 7.19 (20 to 50)
  Level of control, control score (range)a
    Distance2.7 ± 1.2 (0 to 4)
    Near1.9 ± 1.3 (0 to 4)
    Overall4.6 ± 2.1 (0 to 8)
  Results of stereotest
    Lang I test, passed (%)85/90 (94.4)
    Stereo Fly Stereotest (≤ 100 arcsec, %)81/88 (92.0)

Questionnaire for Evaluating Parental Observations of Pediatric Patients With Intermittent Exotropia

Choose one option, or describe any problems you experience that we have not addressed. Express only your own observations or impressions.
1. Onset of exotropia: When did you first notice the exotropia (outward deviation of eye) in your child?
2. Which eye of your child is usually deviated ?   1) Right eye  2) Left eye   3) Both eyes  4) I don't know
3. Degree of awareness: How easy was it for you to notice the exotropia in your child when it manifest?  1) Low, it was not easily noticeable   (including the cases of incidental diagnosis of exotropia during routine eye check-ups, where parents were not able to notice the exotropia but others had noticed it)   2) High, it was easily noticeable
4. Frequency of exotropia: How frequently do you notice the exotropia in your child in daily life?   1) Rarely (once or twice daily)  2) Intermittently, less than 50% of the day   3) Intermittently, more than 50% of the day  4) Constantly
Authors

From the Department of Ophthalmology, Yeungnam University Medical Center, Daegu, Republic of Korea.

The authors have no financial or proprietary interest in the materials presented herein.

Correspondence: Won Jae Kim, MD, Department of Ophthalmology, Yeungnam University Medical Center, Daegu, Republic of Korea. E-mail: eyekwj@gmail.com

Received: December 13, 2019
Accepted: March 13, 2020

10.3928/01913913-20200326-02

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