Journal of Pediatric Ophthalmology and Strabismus

Original Article Supplemental Data

Duane's Retraction Syndrome in a Cohort of South African Children: A 20-Year Clinic-Based Review

Annalien Steyn, MBChB, Dip Ophth(SA); Rhian Grötte, MBBS, FRCSE, FRCOphth; Christopher Tinley, MBChB, FRCOphth (London)

Abstract

Purpose:

To describe the clinical features of Duane's retraction syndrome in a cohort of South African children and to analyze the differences between ethnic groups.

Methods:

A retrospective case series of 120 patients seen between 1997 and 2017 at a tertiary referral center in Cape Town, South Africa.

Results:

Type 2 Duane's retraction syndrome was most common in black children (54%), whereas type 1 was predominant in mixed race (68%) and white (94%) children. In this cohort, 63% of black children with Duane's retraction syndrome were boys, whereas 69% of white children and 59% of mixed race children were girls. Left eye involvement was the most common in all ethnic groups (44%), followed by right eye (41%) and bilateral (14%) involvement. The average age at presentation was 34.2 months (range: 1 to 144 months). Strabismus in primary position was present in 57 patients (46%), of whom 39% had esotropia and 61% had exotropia. A deviation in the primary position was more common in black (71%) children than in mixed race (39%) or white (41%) children. Ametropia was found in 94 patients (79%), amblyopia was present in 15 patients (13%), and 41 patients (34%) underwent surgery.

Conclusions:

This is the first study to provide robust data on the profile of pediatric Duane's retraction syndrome in the three main ethnic groups in South Africa, and it showed clear ethnic differences. Among black children, boys are affected more often, the proportion with type 2 Duane's retraction syndrome is more frequent, and surgery is required more often. Among white and mixed race children, girls are affected more often and type 1 Duane's retraction syndrome is predominant.

[J Pediatr Ophthalmol Strabismus. 2019;56(4):248–253.]

Abstract

Purpose:

To describe the clinical features of Duane's retraction syndrome in a cohort of South African children and to analyze the differences between ethnic groups.

Methods:

A retrospective case series of 120 patients seen between 1997 and 2017 at a tertiary referral center in Cape Town, South Africa.

Results:

Type 2 Duane's retraction syndrome was most common in black children (54%), whereas type 1 was predominant in mixed race (68%) and white (94%) children. In this cohort, 63% of black children with Duane's retraction syndrome were boys, whereas 69% of white children and 59% of mixed race children were girls. Left eye involvement was the most common in all ethnic groups (44%), followed by right eye (41%) and bilateral (14%) involvement. The average age at presentation was 34.2 months (range: 1 to 144 months). Strabismus in primary position was present in 57 patients (46%), of whom 39% had esotropia and 61% had exotropia. A deviation in the primary position was more common in black (71%) children than in mixed race (39%) or white (41%) children. Ametropia was found in 94 patients (79%), amblyopia was present in 15 patients (13%), and 41 patients (34%) underwent surgery.

Conclusions:

This is the first study to provide robust data on the profile of pediatric Duane's retraction syndrome in the three main ethnic groups in South Africa, and it showed clear ethnic differences. Among black children, boys are affected more often, the proportion with type 2 Duane's retraction syndrome is more frequent, and surgery is required more often. Among white and mixed race children, girls are affected more often and type 1 Duane's retraction syndrome is predominant.

[J Pediatr Ophthalmol Strabismus. 2019;56(4):248–253.]

Introduction

Duane's retraction syndrome is a congenital cranial disinnervation disorder. Its characteristic findings include a variety of horizontal motility deficits, accompanied by globe retraction and palpebral fissure narrowing on attempted adduction. It comprises between 1% and 5% of all strabismus syndromes.1,2 Duane's retraction syndrome is classically reported as a sporadic syndrome, with a left-sided and female predominance.3

Various classifications of Duane's retraction syndrome have been suggested,2 and the most commonly used is the Huber classification based on electromyogram findings.4 This classification divides Duane's retraction syndrome into type 1 (marked limitation of abduction), type 2 (marked limitation of adduction), and type 3 (limitation of both abduction and adduction).

The epidemiology of Duane's retraction syndrome seems to vary according to geographical and genetic factors. DeRespinis et al.3 published the first epidemiological data on Duane's retraction syndrome in Americans, and found a 58% female majority, with type 1 being the most common (78%), followed by type 3 (15%) and type 2 (7%). A French study also found a female preponderance and type 1 to be most common.5 However, in a previous study of 75 South African black children, the majority of children with Duane's retraction syndrome were boys (68%) and type 2 was the most common.6

Most reports have emanated from studies on largely white populations in North America and Europe.1–3,5,6 Little is known about the distribution and etiology of Duane's retraction syndrome in children of other ethnic groups and, in particular, data from Africa are sparse. Therefore, the aim of this study was to review all cases of Duane's retraction syndrome presenting to a tertiary pediatric eye clinic in South Africa during a 20-year period.

Patients and Methods

This study was a retrospective, descriptive case series in which the records of all patients diagnosed as having Duane's retraction syndrome at the Red Cross War Memorial Children's Hospital between 1997 and 2017 were reviewed. Patients with incomplete data were excluded. Ethical approval was obtained from University of Cape Town's Institutional Review Board and the research followed the tenets of the Declaration of Helsinki.

The Red Cross War Memorial Children's Hospital in Cape Town, South Africa, is a large, government-administered, tertiary pediatric referral center that treats children younger than 13 years. The hospital serves the populations from the Western (6.3 million) and Northern (1.2 million) Cape Provinces.7 The ethnic distributions in the Western and Northern Capes are similar, with approximately 50% mixed race, 30% black, and 20% white.7 The majority of patients seen at our hospital are of mixed race or black ethnicity. White children and other ethnic groups often have health insurance and are largely managed within the private sector.8

Our mixed race group is heterogeneous with two distinct origins. The first group is made up of descendants of early intermarriages between European settlers and black natives. The second group (the Cape Malays) has historical and genetic ties with ancestors from South-East Asia. For economic reasons, the black population has gradually migrated to the western Cape and belongs mainly to the Xhosa-speaking tribe.9

All patients with Duane's retraction syndrome were referred by local primary health care providers, general practitioners, or hospital pediatricians. They were evaluated by a consultant pediatric ophthalmologist. During evaluation, each child underwent a comprehensive medical history and ocular and orthoptic examination. Data collected included age at presentation, presence of a family history of strabismus, any associated congenital or ocular abnormalities, type and laterality of Duane's retraction syndrome, deviation in primary position, abnormal head posturing, presence of up or down shoots, visual acuity, refraction, presence of amblyopia, whether surgery was performed, and the type of surgery.

A Pearson chi-square test was used to determine if there were any statistically significant differences between proportions and ethnicity.

Results

A total of 120 patients were identified during the 20-year study period. Eighty patients were mixed race, 24 were black, and 16 were white.

In our group, 65 (54%) were female. Type 1 was the most common (63%), followed by type 2 (22%) and type 3 (15%). Left eye involvement was slightly more common than right eye involvement (46% vs 40%, respectively). Bilateral involvement was present in 14%.

The average age at presentation was 34.2 months (range: 1 to 144 months). Five patients (4.2%) had a positive family history of strabismus and 1 patient (0.8%) had a family history of Duane's retraction syndrome. One patient was a twin and the other twin did not have Duane's retraction syndrome. Twelve patients (1%) had associated congenital systemic abnormalities: 5 Goldenhar's syndrome, 4 congenital heart defects (2 of these had esophageal atresia together with the congenital heart defects), 3 cleft palate, 1 club foot, 1 dysmorphism, and 1 hydrocephalus.

Ocular examination revealed a deviation in primary gaze in 53 patients (43%). Subset analysis showed a deviation in primary gaze mainly in type 2 (74%), followed by type 3 (56%) and then type 1 (37%). Esotropias comprised 42% of patients (22 of 53), whereas exotropias comprised 58% of patients (31 of 53). All of the patients with esotropia had type 1 Duane's retraction syndrome. The distribution of patients with exotropia was 20 patients with type 2 (57%) and 11 patients with type 3 (26%).

Data regarding abnormal head position, presence of up and down shoots, refractive errors, and amblyopia, as present in different types, are shown in Table 1.

Comparison of Epidemiological Differences Between Types of Duane's Retraction Syndrome

Table 1:

Comparison of Epidemiological Differences Between Types of Duane's Retraction Syndrome

A total of 41 patients (34%) underwent surgery. The indications for surgery were a deviation in primary gaze, abnormal head posture, and up or down shoots. Two patients required a second surgical procedure.

Bilateral cases were predominantly male (59%), with an incidence of deviation in primary gaze of 82% of patients (14 of 17). Surgery was required in 59% of patients (10 of 17).

Subset analysis revealed variation between children of different ethnic groups (Table 2). In our black children, males were more common (P = .22), type 2 was most prevalent (P = .043), and surgery was required more frequently (P = .009).

Comparison of Epidemiological Differences per Ethnicity

Table 2:

Comparison of Epidemiological Differences per Ethnicity

Discussion

Several epidemiological studies show a marked variation in the clinical features of Duane's retraction syndrome worldwide. These studies are summarized in Table A (available in the online version of this article).3,6,10–19

Previous Epidemiological Studies on Duane's Retraction Syndrome

Table A:

Previous Epidemiological Studies on Duane's Retraction Syndrome

The results from our cohort corroborate findings from a previous study of black South African children with a male preponderance for Duane's retraction syndrome.6 Young6 primarily researched the Zulu ethnic group. The Zulu group has close ties to the Xhosa-speaking tribes, and they have similar origins in the Nguni people. The Nguni are said to have migrated to the Great Lakes region from North Africa before continuing on down south. Due to their common origin, their languages and cultures show marked similarities.9 Zang10 and Park et al.11 found an equal incidence of males and females of Asian descent in China and Korea. All other reports show a female predominance ranging from 55% to 63%.12–19

In most reports, type 1 is the most common, followed by type 3 and then type 2.2–4 In our series, type 1 was the most common (62%), but there were more patients with type 2 (23%) than type 3 (15%). However, our type distribution showed ethnic differences. In our black population, type 2 was the most common (54%), followed by type 1 (33%) and type 3 (14%). These results are also aligned with Young's study of black South African children6 because her results showed a majority of type 2 (58%), followed by type 1 (33%) and then type 3 (9%). No other epidemiological studies have found a type 2 majority. In our mixed race population, there was a large majority of type 1 (68%), whereas type 2 (17%) was slightly more common than type 3 (15%). This may be a reflection of their South-East Asian descent, because other studies from South-East Asian populations showed comparable results. Shrestha and Sharma15 showed that in Nepal, type 1 is most common by a large margin (73%) and that type 2 (15%) is more common than type 3 (12%). Sarfraz et al.19 showed similar results in patients from Pakistan (68%, 20%, and 10%) and Anvari et al.13 showed the same pattern in Iran (87%, 6.5%, and 5.7%).

In our study, bilateral cases of Duane's retraction syndrome comprised 10% in mixed race children, 21% in black children, and 25% in white children. The mixed race findings are in keeping with the 12% bilaterally in India reported by Mohan et al.14 and Kekunnaya et al.,16 as well as the 14% reported by Khan et al.12 in Saudi Arabia and Shawky et al.17 in Egypt. The 21% prevalence of bilateral cases in our black population is in keeping with the findings of Young,6 in which a higher incidence of bilateral cases (33%) was present among black South Africans. Although our numbers were small, we had a high incidence of bilateral cases in our white patients (25%) and Mehel et al.18 in France found the incidence of bilateral disease in their series to be 21.7%.

The average age of presentation varies worldwide from 10 months to 13.84 years, with no statistical difference in the time of presentation of different subtypes.11,14,16 In our setting, the average age at presentation was 34.2 months, with no significant difference in the age of presentation of the different subtypes.

Family history was present in 0.05% in our series. Other series showed that a positive family history for Duane's retraction syndrome and/or strabismus ranges from 0.03% to 10%.4,7,16,19 Sevel and Kasser20 reported three successive generations in South Africa with bilateral Duane's retraction syndrome, suggesting an autosomal dominant inheritance in that family. No other studies describe a heritable mode of transmission of Duane's retraction syndrome and our series supports this notion.21

Congenital systemic abnormalities were present in 1% of patients, whereas congenital ocular abnormalities were present in 0.4% of patients. All of the observed systemic and ocular associations in our patients have been described previously.21,22 Zhang10 and Park et al.11 found a 12% incidence of crocodile tears, whereas Kekunnaya et al.16 found cataract to be their most common ocular association.

Refractive error in the current study was predominantly hypermetropia (74%), with myopia being much less common (0.05%). Hypermetropia is reported to be present in 30% to 80% of patients with Duane's retraction syndrome.21

Amblyopia was found in 12.5% of patients in our study. In other research, amblyopia was documented in 3% to 25% of cases.16,23,24 There was no difference in the incidence of amblyopia according to types and laterality, and this is in keeping with previous reports.

A horizontal deviation in primary position was present in 46% of our cases, with bilateral Duane's retraction syndrome being the most common (82.4%), followed by type 2, type 3, and then type 1 (74%, 56%, and 37%). There are marked geographical differences in the incidence of horizontal deviation in primary gaze in Duane's retraction syndrome, with reports varying from 13.6% to 90.2%.11,13–16,19 The higher incidence of horizontal strabismus in bilateral cases (82% vs 44%) is in keeping with the findings of Mohan et al.,14 Khan and Oystreck,25 and Zanin et al.,26 whereas Kekunnaya et al.16 reported an equal incidence in horizontal strabismus in unilateral and bilateral cases. Only O'Malley et al.27 reported a higher incidence in unilateral cases.

Vertical deviations in the form of up or down shoots were present in 48% of our cases. The incidence of vertical deviations ranges from 12.8% to 61%.10,11,13,16,19 We found vertical deviations were most common in type 3 (81%), followed by type 2 (70%) and then type 1 (34%). Kekunnaya et al. also found an 80% incidence of up and down shoots in type 3.16

An abnormal head posture was found in 50% of cases. This ranges in the literature from 16.7% to 76%.10–11,13,16,18,19 Type 2 had significantly more face turn than type 1 or type 3 and this contrasts with the findings of Kekunnaya et al., where a face turn was significantly less common in type 2.16

Surgery was performed in 34% of cases. Analyzed by subset, type 3 required surgery most often (69%), followed by types 2 (29%) and 1 (29%). Previous reports showed with statistical significance that patients with type 2 Duane's retraction syndrome required surgery more frequently.16,19,27 In the current study, patients with type 3 required surgery most often, and all surgeries for type 3 were at least partially indicated by the presence of up or down shoots (81%).

Limitations of this study largely surround its retrospective, clinic-based design. Incidence rates of Duane's retraction syndrome cannot be inferred because it is not population-based. It is possible that a proportion of the children with Duane's retraction syndrome within the population served by our institution did not present to the clinic and were therefore not included. Unavoidable inaccuracies arose in history-taking due to language barriers, and we relied on caregivers' recollections of the onset of deviation, without the aid of photographs. Nevertheless, this study is the first to provide robust data on the profile of pediatric Duane's retraction syndrome in the three main South African ethnic groups. We found clear ethnic differences in Duane's syndrome in our cohort.

In black children, boys are more commonly affected than girls, the incidence of type 2 Duane's retraction syndrome is more frequent than types 1 and 3, and surgery is required more often. In mixed race children, type 2 is more common than type 3. In mixed race and white children, females and type 1 predominate, following North American and European trends. Further population-based studies on the epidemiology of Duane's retraction syndrome in children are needed to clarify the role of race as a potential risk factor.

References

  1. Gurwood AS, Terringo CA. Duane's retraction syndrome: literature review. Optometry. 2000;71:722–726.
  2. Kekunnaya R, Negaalur M. Duane retraction syndrome: causes, effects and management strategies. Clin Ophthalmol. 2017;11:1917–1930. doi:10.2147/OPTH.S127481 [CrossRef]
  3. DeRespinis PA, Caputo AR, Wagner RS, Guo S. Duane's retraction syndrome. Surv Ophthalmol. 1993;38:257–288. Erratum in: Surv Ophthalmol. 1996;40:423. doi:10.1016/0039-6257(93)90077-K [CrossRef]
  4. Huber A. Electrophysiology of the retraction syndromes. Br J Ophthalmol. 1974;58:293–300. doi:10.1136/bjo.58.3.293 [CrossRef]
  5. Zanin E, Gambarelli N, Denis D. Distinctive clinical features of bilateral Duane retraction syndrome. J AAPOS. 2010;14:293–297. doi:10.1016/j.jaapos.2010.02.010 [CrossRef]
  6. Young S. Characteristics of Duane's retraction syndrome at a clinic in South Africa. Surv Ophthal. 1997;42:295. doi:10.1016/S0039-6257(97)90028-X [CrossRef]
  7. Lehohla P. Census 2011: census in brief. Pretoria, South Africa: Statistics South Africa; 2012. http://www.statssa.gov.za/census/census_2011/census_products/Census_2011_Census_in_brief.pdf
  8. Lalloo R, Myburgh NG, Smith MJ, Solanki GC. Access to health care in South Africa: the influence of race and class. S Afr Med J. 2004;94:639–642.
  9. Beck RB. The History of South Africa, 2nd ed. Santa Barbara, CA: Greenwood; 2014.
  10. Zhang F. Clinical features of 201 cases with Duane's retraction syndrome. Chin Med J (Engl). 1997;110:789–791.
  11. Park WH, Son DH, Yoon SW, Baek SH, Kong SM. The clinical features of Korean patients with Duane's retraction syndrome. Korean J Ophthalmol. 2005;19:132–135. doi:10.3341/kjo.2005.19.2.132 [CrossRef]
  12. Khan AO, Oystreck DT, Wilken K, Akbar F. Duane's retraction syndrome on the Arabian Peninsula. Strabismus. 2007;15:205–208. doi:10.1080/09273970701632023 [CrossRef]
  13. Anvari F, Hatef E, Mohammadi SF, Eskandari A. Duane's retraction syndrome, a case series from Iran. Int Ophthalmol. 2008;28:275–280. doi:10.1007/s10792-007-9125-y [CrossRef]
  14. Mohan K, Sharma A, Pandav SS. Differences in epidemiological and clinical characteristics between various types of Duane retraction syndrome in 331 patients. J AAPOS. 2008;12:567–580. doi:10.1016/j.jaapos.2008.04.015 [CrossRef]
  15. Shrestha GS, Sharma AK. Duane's retraction syndrome: a retrospective review from Kathmandu, Nepal. Clin Exp Optom. 2012;95:19–27. doi:10.1111/j.1444-0938.2011.00635.x [CrossRef]
  16. Kekunnaya R, Gupta A, Sachdeva V, et al. Duane retraction syndrome: series of 441 cases. J Pediatr Ophthalmol Strabismus. 2012;49:164–169. doi:10.3928/01913913-20111101-01 [CrossRef]
  17. Shawky D, Gaballa K, El Basha M. Duane retraction syndrome, Egyptian study. Adv Ophthalmol Vis Syst. 2015;3:00089.
  18. Mehel E, Quere MA, Lafenant F, Pechereau A. Epidemiological and clinical aspects of Stilling-Turk-Duane syndrome [article in French]. J Fr Ophtalmol. 1996;19:533–542.
  19. Sarfraz S, Nuzhat S, Khan A. Duane's syndrome: surgical outcome and non ophthalmologic associations. J Ayub Med Coll Abbottabad. 2014;26:328–330.
  20. Sevel D, Kassar BS. Bilateral Duane syndrome: occurrence in three successive generations. Arch Ophthalmol. 1974;91:492–494. doi:10.1001/archopht.1974.03900060506017 [CrossRef]
  21. Kekunnaya R, Negalur M. Duane retraction syndrome: causes, effects and management strategies. Clin Ophthalmol. 2017;11:1917–1930. doi:10.2147/OPTH.S127481 [CrossRef]
  22. Assaf AA. Congenital innervation dysgenesis syndrome (CID)/congenital cranial disinnervation disorders (CCDDs). Eye (Lond). 2001;25:1251–1261. doi:10.1038/eye.2011.38 [CrossRef]
  23. Tredici TD, van Noorden GK. Are anisometropia and amblyopia common in Duane's syndrome?J Pediatr Ophthalmol Strabismus. 1985;22:23–25.
  24. Kirkham TH. Anisometropia and amblyopia in Duane's syndrome. Am J Ophthalmol. 1970;69:774–777. doi:10.1016/0002-9394(70)93419-7 [CrossRef]
  25. Khan AO, Oystreck D. Clinical characteristics of bilateral Duane syndrome. J AAPOS. 2006;10:198–201. doi:10.1016/j.jaapos.2006.02.001 [CrossRef]
  26. Zanin E, Gambarelli N, Denis D. Distinctive clinical features of bilateral Duane retraction syndrome. J AAPOS. 2010;14:293–297. doi:10.1016/j.jaapos.2010.02.010 [CrossRef]
  27. O'Malley ER, Helveston EM, Ellis FD. Duane's retraction syndrome-plus. J Pediatr Ophthalmol Strabismus. 1982;19:161–165.

Comparison of Epidemiological Differences Between Types of Duane's Retraction Syndrome

CharacteristicType 1Type 2Type 3
No.752718
Age (months)39.929.733.9
Male28 (37%)18 (67%)8 (44%)
Female47 (63%)9 (33%)10 (56%)
Right eye27 (36%)10 (37%)11 (61%)
Left eye36 (48%)14 (52%)5 (28%)
Bilateral12 (16%)3 (11%)2 (11%)
Esotropia22 (29%)00
Exotropia020 (74%)11 (61%)
Hypermetropia44 (59%)19 (70%)13 (72%)
Myopia1 (1%)2 (7%)3 (17%)
Amblyopia10 (13%)3 (1%)2 (11%)
Face turn32 (43%)18 (67%)9 (50%)
Up or down shoots25 (33%)19 (70%)15 (83%)
Surgery22 (29%)8 (30%)11 (61%)

Comparison of Epidemiological Differences per Ethnicity

CharacteristicBlackMixed RaceWhite
No.248116
Male:Female62.5%41%31%
Type 133%68%94%
Type 254%17%6%
Type 314%15%0%
Right:Left29%47%25%
Bilateral21%10%25%
Deviation in primary position71%39.5%44%
Exotropia82%60%14%
Esotropia18%40%86%
Abnormal head posture58%51%38%
Surgery33%15%37.5%

Previous Epidemiological Studies on Duane's Retraction Syndrome

CountrySouth AfricaSouth AfricaUSAChinaKoreaSaudi ArabiaIranIndiaNepalIndiaEgyptFrancePakistan
AuthorSteynYoung6DeRespinis4Zang10Park11Khan12Anvari13Mohan14Shresta15Kekhunnaya16Shawky17Mehel18Sarfraz19
Date2018199719931997200520072005200820122012201519962014
Number12075201784041283314144119815541
Bilat %14331831471251214212
Left eye %453559668378656868587266
Right eye %413123142223272028723
Females %5432.558505155606058.552485463
Males %4667.542504945404041.548524637
Type 1 %62.5337891.58678877373837368
Type 2 %22.55872474152520
Type 3 %1591512196111232210
Deviation in primary %44411465596590
AHP %494016.771606576
Shoots %49201513244861
Surgery %3440714763
Amblyopia %135272710101533
Systemic abn %1631115
Ocular abn %0.41212814
Fam hx %0.51086
Authors

From the Department of Ophthalmology, Red Cross War Memorial Children's Hospital, Cape Town, South Africa; and the Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.

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

Correspondence: Annalien Steyn, MBChB, Dip Ophth(SA), Red Cross War Memorial Children's Hospital, Klipfontein Road, Rondebosch, Cape Town, Western Cape 7700, South Africa. E-mail: annalienlerm@gmail.com

Received: February 05, 2019
Accepted: March 26, 2019

10.3928/01913913-20190416-01

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