ABSTRACT The Korean Intermittent Exotropia Multicenter Study (KIEMS) was a retrospective, cross-sectional and multicenter study for the investigation of intermittent exotropia involved 65

strabismus specialists from 53 institutions in Korea. Purpose of this study was to present ophthalmologic findings of intermittent exotropia from the KIEMS. Consecutive patients with

intermittent exotropia of ≥ 8 prism diopters (PD) at distance or near fixation were included. Best-corrected visual acuity, cycloplegic refraction data, angles of deviation at several

cardinal positions, ocular dominance, fusion control, oblique muscle function, and binocular sensory outcomes were collected. A total of 5385 participants (2793 females; age 8.2 years) were

near than at distance fixation. Good stereopsis at 40 cm was observed in 49.3% in Titmus stereo test (≤ 60 arcsec) and in 71.0% in Randot stereo test (≤ 63 arcsec). Intermittent exotropia

was mostly diagnosed in childhood and patients with the condition showed relatively good binocular functions. This study may provide objective findings of intermittent exotropia in a most

reliable way, given that the study included a large study population and investigated comprehensive ophthalmology examinations. SIMILAR CONTENT BEING VIEWED BY OTHERS BINOCULAR FUNCTION IN

PATIENTS WITH INTERMITTENT EXOTROPIA ACCOMPANIED BY UNILATERAL CONGENITAL PTOSIS Article Open access 31 October 2022 CLINICAL CHARACTERISTICS AND RISK FACTORS OF ACUTE ACQUIRED CONCOMITANT

ESOTROPIA IN LAST 5 YEARS: A RETROSPECTIVE CASE–CONTROL STUDY Article 24 January 2022 CLINICAL FEATURES AND CHANGE IN INCIDENCE OF ACUTE ACQUIRED COMITANT ESOTROPIA: A 15-YEAR SINGLE-CENTRE

STUDY IN SOUTH KOREA Article 01 February 2024 INTRODUCTION Intermittent exotropia is an outward drifting of either eye in a latent or intermittent form1,2. It is a predominant form of

strabismus in East Asian countries3,4,5,6, including Korea7,8, and is also common in the United States9 and some European countries10. Although many clinical studies have been conducted on

this common disease entity, many questions remain unanswered11. The interpretations of the results of many clinical studies on intermittent exotropia have been confusing owing to variable

study settings, different study protocols, and the clinical variability of this condition12. Mostly, previous studies focused on the surgical results and included patients with relatively

large angle of exotropia requiring surgery13,14,15,16,17, which might exclude the clinical findings of relatively small angle intermittent exotropia. Also, those studies reported various

types of stereoacuity, binocularity, ocular dominance and fusion control tests11,12, which were not interchangeable for comparison. Most ophthalmologic examinations for diagnosis of

intermittent exotropia depended largely on the examiners’ skill because those examinations can be performed only manually. To obtain comprehensive and convincing information about the

clinical characteristics of intermittent exotropia, a large-scale study, regardless of clinical considerations, such as age, amount of exotropia angle, and necessity of surgical

intervention, is needed. Also, the ophthalmologic examinations need to be conducted by strabismus specialists using a standardized protocol. The Korean Intermittent Exotropia Multicenter

Study (KIEMS) is a large-scale nationwide and multicenter study investigating the clinical features of intermittent exotropia using a standardized protocol. It was initiated by the Korean

Association of Pediatric Ophthalmology and Strabismus (KAPOS), whose members are strabismus specialists. The KIEMS is one of the largest clinical studies on intermittent exotropia to date

and is expected to present the overall features, including the subjective and objective features, of intermittent exotropia. This study was conducted to present the objective ophthalmologic

findings from the KIEMS. RESULTS BASELINE CHARACTERISTICS OF PARTICIPANTS A total of 5385 participants were included in this study with age of 8.2 ± 7.6 years (mean ± standard deviation;

range, 0.3–106.7 years). The age distribution of all participants has been previously described18. The mean spherical equivalent (SE) was – 0.57 ± 1.89 diopters (D) (range, + 7.0 to − 12.88

D) in the right eye and -0.61 ± 1.96 D (range, + 8.75 to − 14.00 D) in the left eye (_P_ = 0.666, paired t-test). The non-dominant eye at distance fixation tended to be more myopic than the

dominant eye (SE: − 0.60 ± 1.98 vs. − 0.47 ± 1.74 D, _P_ < 0.001, paired t-test) (Table 1). Of the 5385 participants, 2793 (51.9%) were females and 2592 (48.1%) were males, showing a

slight female predominance. Male participants were older than female participants (8.6 ± 7.3 vs. 7.8 ± 7.8 years, independent t-test, _P_ < 0.001). According to the mean SE, the right and

left eyes of male participants were more myopic than those of female participants (independent t-test, _P_ < 0.001). Hyperopia (mean SE >  + 1 D), emmetropia (≤ + 1 and ≥ − 1 D), and

myopia (< − 1 D) were observed in 12.0% (507/4219), 55.4% (2338/4219), and 32.6% (1374/4219) participants, respectively. The mean exodeviation angle in the primary position at distance

fixation was 23.2 ± 9.0 PD in males, which was smaller than that in females (23.7 ± 8.6 PD) (independent t-test, _P_ = 0.036). With respect to the mean exodeviation angle at near fixation,

no sex difference was observed (25.0 ± 9.4 vs. 25.1 ± 9.3 PD, independent t-test, _P_ = 0.543). ANGLES OF EXODEVIATION The mean angle of exodeviation in the primary position was 23.5 ± 8.8

(range, 0–85) PD at distance fixation and 25.0 ± 9.3 (range, 0–90) PD at near fixation. Basic-type exotropia (difference between distant and near angles ≤ 10 PD), convergence

insufficiency-type exotropia (near–distant angle < 10 PD), and divergence excess-type exotropia (distant–near angle > 10 PD) were observed in 86.2% (4599/5331), 9.4% (500/5331), and

4.4% (232/5331), respectively. Participants with convergence insufficiency-type exotropia were older than those with basic- and divergence excess-type exotropia (independent t-test,

Bonferroni corrected _P_ < 0.001). The exodeviation angles in the secondary and head-tilted positions were smaller than those in the primary position (Table 2, paired t-test, _P_ < 

0.001). Lateral incomitance was present in 2.3% (95/4164) in right gaze and in 2.0% (83/4166) in left gaze. Lateral incomitance in both right gaze and left gaze was present in 1.5%

(63/4163). The A and V patterns of exotropia were observed in 0.9% (35/3889) and 1.1% (44/3889), respectively. OCULAR DOMINANCE AND FUSION CONTROL Ocular dominance in the right or left eye

was present in 51.7% (29.1% for the right eye, 22.6% for the left eye, 2407/4655) at distance fixation and in 39.0% (22.1% for the right eye, 16.9% for the left eye, 1725/4422) at near

fixation. Alternating ocular dominance was observed in 48.3% (2248/4655) and 61.0% (2697/4422) at distance and near fixation, respectively. The ratio of alternating ocular dominance was

significantly higher at near than at distance fixation (_P_ < 0.001, Pearson’s chi-square test). In the assessment of fusion control, the proportion of participants with good and fair

control was 27.6% (1336/4835) and 41.6% (2010/4835) at distance fixation and 42.6% (1977/4641) and 37.1% (1723/4641) at near fixation, respectively. The proportion of participants who showed

poor fusion control was 30.8% (1489/4835) at distance fixation and 20.3% (941/4641) at near fixation. Fusion control was better at near than at distance fixation (_P_ < 0.001, Pearson’s

chi-square test). ASSOCIATED STRABISMUS Inferior oblique overaction (IOOA) was present in 25.5% of the participants (1092/4278), whereas superior oblique overaction (SOOA) was observed in

only 6.0% (249/4120). Bilateral IOOA and SOOA (15.5% and 3.4%, respectively) were more common than unilateral IOOA and SOOA (10.0% and 2.6%, respectively). In contrast, inferior and superior

oblique under actions were relatively rare (0.4% and 2.5%, respectively) (Table 3). Vertical deviation of ≥ 5 PD in the primary position was present in 4.9% (266/5385) (Table 1).

Dissociated vertical deviation was present in 0.6% of the participants (35/5385) (Table 1). SENSORY STATUS EVALUATIONS In the Worth four-dot test at 6 m, 49.6% of the participants

(1924/3881) saw four lights, which was interpreted as “fusion” if normal retinal correspondence existed; 35.7% (1385/3881) saw two or three lights, recorded as “suppression”; and 14.7%

(572/3881) saw five lights, recorded as “diplopia.” Histograms of the Titmus (circles) and Randot stereo test results at 40 cm are shown in Fig. 1A and B. “Good stereopsis,” defined as ≤ 60

arcsec in the Titmus stereotest and as ≤ 63 arcsec in the Randot stereo test, was observed in 49.3% (1657/3358) and 71.0% (697/982), respectively. DISCUSSION This study described the

objective examination findings from the KIEMS, which is one of the largest clinical studies on intermittent exotropia to date. Although many previous studies on the clinical characteristics

of intermittent exotropia have been conducted, the KIEMS is expected to provide the most comprehensive and reliable overview of the clinical spectra of intermittent exotropia in terms of

sample size and study parameters. In this study, the number of female participants (51.9%) was comparable to that of male participants (48.1%). In a previous population-based cohort study

including participants aged < 19 years in the United States, a female predominance (64.1%) was reported19. Another multicenter cohort study in the United Kingdom also reported a slight

female predominance (55.9%) in children aged < 12 years with untreated intermittent exotropia20. In contrast, in Singaporean4 and Chinese5 population-based studies in children aged < 6

 years (mostly of Chinese ethnicity), the prevalence of exotropia showed no sex difference when compared with the general population. In addition, a previous population-based study in Korea

reported that sex was not significantly associated with clinically significant intermittent exotropia (≥ 15 PD) in adolescence7. Studies in Asian countries including our study have found no

sex predominance in the prevalence of intermittent exotropia, whereas Western studies tended to show a female predominance. Future studies with age or ethnicity standardization are needed to

clarify the sex differences in intermittent exotropia. In this study, basic-type exotropia (86.2%) was the predominant type followed by convergence insufficiency-type (9.4%) and divergence

excess-type (4.4%) exotropia when classified based on a ≥ 10 PD difference between the distant and near exotropia angles. Patients with the convergence insufficiency type were older than

those with the other two types. Similarly, a recent study in Korea reported that basic-type exotropia was the most prevalent type (79.2%) in 355 patients with exotropia14. A population-based

study from China reported a 74.7% prevalence of basic-type exotropia in 166 patients with intermittent exotropia aged 3–6 years5. Rutstein and Corliss also reported basic-type exotropia as

the most common type in 73 patients21. A study from Singapore reported that divergence excess-type exotropia had a higher prevalence (59.5%) than basic-type exotropia (27%) in 453 patients

with intermittent exotropia; however, the authors speculated that some patients with basic-type exotropia may have been inadvertently classified to the divergence excess type, as the

children were not routinely patched to eliminate tenacious proximal fusion22. However, Burian and Franceschetti observed basic-type exotropia in 33% and convergence insufficiency-type

exotropia in 55% of 237 prospectively collected consecutive patients, although they used stricter standards in classifying cases as convergence insufficiency-type exotropia23. Kushner and

Morton observed divergence excess-type exotropia in 48.5%, which was the most prevalent type, although it included 80 patients (39.6% of the total participants) with simulated divergence

excess (within a distant–near angle difference of 10 PD after 1 h of monocular patching), and basic-type exotropia in 38.6% of 202 patients with intermittent exotropia24. They reported that

convergence insufficiency-type exotropia was more common in older participants, consistent with the current study (Table 4). The proportion of intermittent exotropia types may be affected by

the inclusion criteria used or the clinical characteristics of the participants. Alternating ocular dominance (48.3% at distance, 61.0% at near) was more common than right or left dominance

(29.1% for the right eye and 22.6% for the left eye at distance; 22.1% for the right eye and 16.9% for the left eye at near) in this study. The proportion of alternating ocular dominance at

near fixation was larger than that at distance fixation. Similarly, fusion control was better under the near viewing condition than under the distant viewing condition in this study.

Previous studies investigating fusion control in patients with intermittent exotropia showed similar results25,26,27. In monocular dominance, there is a preference for one eye over the other

eye under the binocular viewing condition, whereas no such preference exists in alternating ocular dominance28. It is well known that patients with intermittent exotropia rarely manifest

amblyopia in either eye (if amblyopia occurs, it mostly manifests in the non-dominant eye) because the eyes can remain aligned at least in the near fixation condition29. Therefore, the

result of this study confirmed that patients with intermittent exotropia show good binocular interaction. More than 60% of the participants saw four or five lights in the distant Worth

four-dot test, which suggests that patients with intermittent exotropia have relatively good binocular function at distant fixation, in which the sensory function of one eye does not

overwhelm that of the other eye; however, seeing four lights in the test does not necessarily mean that the participants had central foveal fusion30. Monocular suppression was observed in 

< 40% of the patients, evenly in each eye. In the Titmus stereotest at 40 cm, approximately 50% of the participants showed good stereopsis of ≤ 60 arcsec, reflecting central fusion at

near fixation. Moreover, in the Randot stereoacuity test at near fixation, > 70% of the participants showed ≤ 63 arcsec of stereopsis. Romanchuk et al. reported that 72.5% of their 109

patients showed better stereopsis than 60 arcsec in the Titmus stereo test even after ≥ 9 years follow-up from the initial visit31. Similarly, Mohney et al. reported that 63% of 152 patients

showed 60 arcsec or better stereopsis in the Randot stereo test in a Pediatric Eye Disease Investigator Group study32. It is well known that patients with intermittent exotropia have

relatively good near stereopsis1. The participants in this study can be assumed to have similarly good binocular functions, as previously reported. This study should be viewed in the light

of its limitations. Owing to the retrospective study design, data collection could not be performed as strictly as in a prospective study, which may have inevitably biased the patient

selection or data collection process. Moreover, data were collected from 65 strabismus specialists from 53 different institutions and the circumstances of ophthalmologic examinations may

have been different among the investigators, possibly affecting the study results. Despite efforts to reduce variability through the use of a standardized protocol and standardized case

report forms, this study had the same limitations as many other multicenter studies. In conclusion, this large observational study that included 5385 participants reported the objective

findings of intermittent exotropia. In most of the study participants, intermittent exotropia was diagnosed during childhood (age, 8.2 ± 7.6 years). Basic-type exotropia was the most common

type, followed by the convergence insufficiency and divergence excess types. In the assessment of fusion control, good to fair control was observed in 69.2% at distance fixation and in 79.8%

at near fixation, and “good stereopsis” (\(\le\) 60 arcsec in the Titmus stereotest and ≤ 63 arcsec in the Randot stereo test) was observed in 49.3% and 71.0%, respectively. This study

potentially provides the most reliable information on the general clinical spectra of intermittent exotropia thus far, given the large study size and the coordination among many specialized

investigators. Future studies using the KIEMS data are expected to provide more information about various aspects of intermittent exotropia. METHODS The KIEMS is a nationwide, retrospective,

observational, cross-sectional, and multicenter study. The protocol of the KIEMS has been described elsewhere18. Briefly, the study was conducted as a collaboration among 65 strabismus

specialists who were members of KAPOS and affiliated with 53 institutions in Korea. The medical records of patients who visited the eye clinic of each institution for the first time between

March 1, 2019, and February 29, 2020, were reviewed. Participants with intermittent exotropia with ≥ 8 prism diopters (PD) at distance fixation (at 6 m) or near fixation (33 cm) in the prism

and alternate cover test (PACT), regardless of age, were included in this study. Participants who had previous strabismus surgery history were excluded. Participants were excluded if they

had signs of incomitant strabismus, ocular conditions affecting vision or prior ocular surgical history, chromosomal anomalies, or systemic disorders such as congenital anomalies or

neurologic disorders. The KIEMS protocol conformed to the tenets of the Declaration of Helsinki. The protocol was approved by the Institutional Review Board of Kim’s Eye Hospital (KEH

2020-05-007) and by each participating institution. The requirement for informed consent was waived by the Institutional Review Board of Kim’s Eye Hospital because the study used

retrospectively collected clinical data and the data were accessed anonymously. The KIEMS collected data from subjective questionnaires completed by patients or guardians and from the

results of objective ophthalmologic examinations conducted by strabismus specialists. In this study, we collected and analyzed the following objective data from ophthalmologic examinations

in the KIEMS: age, sex, best-corrected visual acuity, refractive errors measured using cycloplegic refraction with 1% cyclopentolate hydrochloride (Cyclogyl; Alcon Lab. Inc., Fort Worth, TX,

USA) and 1% tropicamide (Mydriacyl, Alcon Lab. Inc.), angles of deviation in PACT (in the primary, secondary, and head-tilted positions under distant [6 m] and near [33 cm] viewing

conditions using accommodative targets with the patients’ best optical correction), and associated strabismus (e.g., dissociated vertical deviation, vertical deviation, and oblique muscle

dysfunction). Vertical deviation was defined as hypertropia/hypotropia of ≥ 5 PD in the primary position. Lateral incomitance was defined as a decrease in the exo-angle of ≥ 20% in the right

or left gaze, as compared with that in the primary position. “A” pattern exotropia was defined as a condition in which the exotropia angle at down gaze was higher by ≥ 10 PD than that at up

gaze. Likewise, “V” pattern exotropia was defined as a condition in which the exotropia angle at up gaze was higher by ≥ 15 PD than that at down gaze. Right or left ocular dominance was

determined to be present when the right or left eye had a shorter duration of dissociation during the uncover test, and alternating ocular dominance was identified when the duration of

dissociation was similar between the two eyes. Fusion control under the distant and near viewing conditions was also investigated and classified as follows: good control, when ocular fusion

was disrupted only after the cover test at distance fixation and was rapidly regained without blinking or fixating ocular movements; fair control, when ocular fusion was regained only after

blinking or fixating movements after disruption with cover testing at distance fixation; and poor control, when ocular fusion was spontaneously broken without fusion disruption or was not

regained despite blinking or refixation33. For sensory status evaluation, the Worth four-dot test (Richmond Products, Albuquerque, NM, USA) under the distant viewing condition and either the

Titmus stereotest (Stereo Optical Co., Inc., Chicago, IL, USA) or Randot stereotest (Vision Assessment Corporation, Elk Grove Village, IL, USA) under the near viewing condition were

performed. Stereoacuity of ≤ 60 arcsec in the Titmus stereotest or ≤ 63 arcsec in the Randot stereo test was defined as “good stereopsis.” More detailed findings of the ophthalmologic

examinations are provided in an article describing the KIEMS methodology18. Statistical analysis was performed using SPSS (version 21.0; IBM Corporation, Armonk, NY, USA). Statistical

significance was set at _P_ < 0.05. Bonferroni correction was applied to the _P_ value for subgroup analyses. Mean ages were compared between male and female participants using an

independent t-test. Exodeviation angles in the secondary positions and in the right and left head-tilted positions, compared with the exodeviation angle in the primary position, were

analyzed using a paired t-test. The differences in the ratios of ocular dominance and fusion control at distant and near fixation conditions were compared using Pearson’s chi-square test.

DATA AVAILABILITY Data supporting the findings of the current study are available from the corresponding author upon reasonable request. CHANGE HISTORY * _ 14 FEBRUARY 2023 A Correction to

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Multicenter Study (KIEMS) was initiated and financially supported by the Korean Association of Pediatric Ophthalmology and Strabismus. AUTHOR INFORMATION Author notes * A list of authors and

their affiliations appears at the end of the paper. AUTHORS AND AFFILIATIONS * Department of Ophthalmology, Kim’s Eye Hospital, Seoul, Korea Dae Hee Kim, Seung-Hee Baek, Dae Hee Kim, 

Seung-Hee Baek, Dae Hee Kim, Ungsoo S. Kim & Daye Choi * Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea Jae

Ho Jung, Jae Ho Jung & Seong-Joon Kim * Department of Ophthalmology, Chungbuk National University College of Medicine, Chungbuk National University Hospital, Cheongju, Korea Mi Young

Choi & Mi Young Choi * Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea Jeong-Min Hwang, Hee Kyung

Yang, Jeong-Min Hwang & Hee Kyung Yang * Department of Ophthalmology, Pusan National University School of Medicine, Yangsan Pusan National University Hospital, Yangsan, Korea Su Jin Kim 

& Su Jin Kim * Department of Ophthalmology, Chungnam National University College of Medicine, Chungnam National University Hospital, Daejeon, Korea Yeon-hee Lee & Yeon-hee Lee *

Department of Ophthalmology, Yonsei University College of Medicine, Severance Eye Hospital, Seoul, Korea Sueng-Han Han & Sueng-Han Han * Department of Ophthalmology, Hallym University

College of Medicine, Kangnam Sacred Heart Hospital, 1, Singil-Ro, Yeongdeungpo-Gu, Seoul, 07441, Republic of Korea Dong Gyu Choi, Dong Gyu Choi & Dong Gyu Choi * Department of

Ophthalmology, Pusan National University Hospital, Busan, Korea Hee-young Choi, Hee-young Choi & Hyeshin Jeon * Department of Ophthalmology, Asan Medical Center, Seoul, Korea Hyun Taek

Lim, Hyun Taek Lim & Hyosook Ahn * Department of Ophthalmology, Seoul St. Mary’s Hospital, Seoul, Korea Shin Hae Park & Sun Young Shin * Department of Ophthalmology, Jeonbuk National

University Hospital, Jeonju, Korea Haeng-Jin Lee * Department of Ophthalmology, Daegu Catholic University Medical Center, Daegu, Korea Sook-Young Kim * Department of Ophthalmology, Keimyung

University DongSan Hospital, Daegu, Korea Dong Cheol Lee, Se-Youp Lee, Se-Youp Lee & Dong Cheol Lee * Department of Ophthalmology, Nune Eye Hospital, Seoul, Korea Hyo Jung Gye & 

Yoonae A. Cho * Department of Ophthalmology, Soonchunhyang University Cheonan Hospital, Cheonan, Korea So Young Kim * Department of Ophthalmology, Nune Eye Hospital, Daegu, Korea Jihyun Park

 & Mirae Kim * Department of Ophthalmology, Dong-A University Hospital, Busan, Korea Won Yeol Ryu & Won Yeol Ryu * Department of Ophthalmology, Siloam Eye Hospital, Seoul, Korea Hye

Sung Park * Department of Ophthalmology, Gachon University Gil Medical Center, Incheon, Korea Hae Jung Paik * Department of Ophthalmology, Hallym University Sacred Heart Hospital, Anyang,

Korea Joo Yeon Lee * Department of Ophthalmology, Samsung Changwon Hospital, Changwon, Korea Shin Yeop Oh * Department of Ophthalmology, Inje University Haeundae Paik Hospital, Busan, Korea

Soo Jung Lee * Department of Ophthalmology, Ajou University Hospital, Suwon, Korea Seung Ah Chung * Department of Ophthalmology, Inje University Sanggye Paik Hospital, Seoul, Korea Jin Choi

* Department of Ophthalmology, Samsung Medical Center, Seoul, Korea Sei Yeul Oh & Kyung-Ah Park * Department of Ophthalmology, Korea University Ansan Hospital, Ansan, Korea Young-Woo Suh

* Department of Ophthalmology, Bucheon St. Mary’s Hospital, Bucheon, Korea Nam Yeo Kang * Department of Ophthalmology, Eunpyeong St. Mary’s Hospital, Seoul, Korea Hae Ri Yum * Department of

Ophthalmology, Sungmo Eye Hospital, Busan, Korea Sun A. Kim * Department of Ophthalmology, Soonchunhyang University Seoul Hospital, Seoul, Korea Hyuna Kim & Songhee Park * Department of

Ophthalmology, Gangnam Severance Hospital, Seoul, Korea Jinu Han * Department of Ophthalmology, Hangil Eye Hospital, Incheon, Korea Hyunkyung Kim * Department of Ophthalmology, Bundang CHA

Medical Center, Seongnam, Korea Helen Lew * Department of Ophthalmology, Wonju Severance Christian Hospital, Wonju, Korea Sang Hoon Rah * Department of Ophthalmology, Kangwon National

University Hospital, Chuncheon, Korea Yung-Ju Yoo * Department of Ophthalmology, Ewha Womans University Mokdong Hospital, Seoul, Korea Key Hwan Lim & Key Hwan Lim * Daegu Premier Eye

Center, Daegu, Korea Jung Ho Lee * Department of Ophthalmology, SMG-SNU Boramae Medical Center, Seoul, Korea Hokyung Choung * Department of Ophthalmology, Konkuk University Medical Center,

Seoul, Korea Hyun Jin Shin * Department of Ophthalmology, Kangbuk Samsung Hospital, Seoul, Korea So Young Han * Department of Ophthalmology, Chonnam National University Hospital, Gwangju,

Korea Hwan Heo * Department of Ophthalmology, Saevit Eye Hospital, Goyang, Korea Soochul Park * Magok Dream Light Eye Clinic, Seoul, Korea Sung Eun Kyung * Department of Ophthalmology, Kosin

University Gospel Hospital, Busan, Korea Changzoo Kim * Department of Ophthalmology, Nowon Eulji Medical Center, Seoul, Korea Eun Hye Jung * Department of Ophthalmology, Hanyang University

Guri Hospital, Guri, Korea Eun Hee Hong * Department of Ophthalmology, Hanyang University Hospital, Seoul, Korea Han Woong Lim & Han Woong Lim * Department of Ophthalmology, Hallym

University Kangdong Sacred Heart Hospital, Seoul, Korea Youn Joo Choi * Department of Ophthalmology, Chungang University Hospital, Seoul, Korea Nam Ju Moon * Department of Ophthalmology,

Korea Cancer Center, Goyang, Korea In Jeong Lyu * Department of Ophthalmology, Dongguk University Hospital, Gyeongju, Korea Soon Young Cho Authors * Dae Hee Kim View author publications You

can also search for this author inPubMed Google Scholar * Jae Ho Jung View author publications You can also search for this author inPubMed Google Scholar * Mi Young Choi View author

publications You can also search for this author inPubMed Google Scholar * Jeong-Min Hwang View author publications You can also search for this author inPubMed Google Scholar * Su Jin Kim

View author publications You can also search for this author inPubMed Google Scholar * Yeon-hee Lee View author publications You can also search for this author inPubMed Google Scholar *

Sueng-Han Han View author publications You can also search for this author inPubMed Google Scholar * Dong Gyu Choi View author publications You can also search for this author inPubMed 

Google Scholar CONSORTIA THE KOREAN ASSOCIATION OF PEDIATRIC OPHTHALMOLOGY AND STRABISMUS (KAPOS) * KIEMS WRITING COMMITTEE (LISTED IN ALPHABETICAL ORDER OF LAST NAME) * Seung-Hee Baek * , 

Hee-young Choi * , Dong Gyu Choi * , Dae Hee Kim * , Dong Cheol Lee * , Se-Youp Lee * , Han Woong Lim * , Hyun Taek Lim * , Key Hwan Lim * , Won Yeol Ryu *  & Hee Kyung Yang * KIEMS

INVESTIGATORS IN THE KAPOS (LISTED IN THE ORDER OF NUMBER OF PATIENTS CONTRIBUTED BY EACH INVESTIGATOR) * Hee-young Choi * , Hyun Taek Lim * , Jae Ho Jung * , Seung-Hee Baek * , Mi Young

Choi * , Jeong-Min Hwang * , Su Jin Kim * , Yeon-hee Lee * , Sueng-Han Han * , Shin Hae Park * , Haeng-Jin Lee * , Sook-Young Kim * , Se-Youp Lee * , Hyo Jung Gye * , So Young Kim * , Sun

Young Shin * , Jihyun Park * , Won Yeol Ryu * , Hye Sung Park * , Dae Hee Kim * , Hae Jung Paik * , Dong Gyu Choi * , Joo Yeon Lee * , Hee Kyung Yang * , Shin Yeop Oh * , Soo Jung Lee * , 

Seung Ah Chung * , Jin Choi * , Sei Yeul Oh * , Mirae Kim * , Young-Woo Suh * , Nam Yeo Kang * , Hae Ri Yum * , Sun A. Kim * , Hyuna Kim * , Jinu Han * , Yoonae A. Cho * , Hyunkyung Kim * , 

Helen Lew * , Dong Cheol Lee * , Sang Hoon Rah * , Yung-Ju Yoo * , Key Hwan Lim * , Hyosook Ahn * , Ungsoo S. Kim * , Jung Ho Lee * , Hokyung Choung * , Seong-Joon Kim * , Hyeshin Jeon * , 

Hyun Jin Shin * , So Young Han * , Hwan Heo * , Soochul Park * , Songhee Park * , Sung Eun Kyung * , Changzoo Kim * , Kyung-Ah Park * , Eun Hye Jung * , Eun Hee Hong * , Han Woong Lim * , 

Daye Choi * , Youn Joo Choi * , Nam Ju Moon * , In Jeong Lyu *  & Soon Young Cho CONTRIBUTIONS Design and conduct of the study (D.H.K., J.H.J., M.Y.C., J-M.H., S.J.K., Y-h.L., S.-H.H.,

D.G.C.); collection of data (D.H.K., J.H.J., M.Y.C., J-M.H, S.J.K., Y-h.L., S.-H.H., D.G.C.); analyses and interpretation of data (D.H.K, J.H.J., M.Y.C., J-M.H., S.J.K., Y-h.L., S.-H.H.,

D.G.C.); writing the manuscript (D.H.K., D.G.C.); critical revision of the manuscript (D.H.K., J.H.J., M.Y.C., J.-M.H, S.J.K., Y-h.L., S.-H.H., D.G.C.); and final approval of the manuscript

(D.H.K., J.H.J., M.Y.C., J.-M.H., S.J.K., Y-h.L., S.-H.H., D.G.C.). CORRESPONDING AUTHORS Correspondence to Dong Gyu Choi, Dong Gyu Choi or Dong Gyu Choi. ETHICS DECLARATIONS COMPETING

INTERESTS The authors declare no competing interests. ADDITIONAL INFORMATION PUBLISHER'S NOTE Springer Nature remains neutral with regard to jurisdictional claims in published maps and

institutional affiliations. The original online version of this Article was revised: The original version of the Article contained errors in the Consortia author list of The Korean

Association of Pediatric Ophthalmology and Strabismus (KAPOS), where author names Dong Gyu Choi and Dae Hee Kim were duplicated in the KIEMS writing committee, and Jae Ho Jung, Mi Young

Choi, Jeong Min Hwang, Su Jin Kim, Yeon hee Lee, Sueng Han Han and Dong Gyu Choi were duplicated in KIEMS investigators in the KAPOS. RIGHTS AND PERMISSIONS OPEN ACCESS This article is

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cross-sectional study of ophthalmologic examination findings in 5385 Koreans presenting with intermittent exotropia. _Sci Rep_ 13, 1329 (2023). https://doi.org/10.1038/s41598-023-28015-2

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