Kerala Journal of Ophthalmology

: 2020  |  Volume : 32  |  Issue : 1  |  Page : 87--88

Concerns in the surgical treatment of intermittent exotropia

Sanitha Sathyan 
 Department of Ophthalmology, Chaithanya Eye Institute, Kochi; Vettam Eye Clinic, Mulanthuruthy, Ernakulam, Kerala, India

Correspondence Address:
Dr. Sanitha Sathyan
Vettam Eye Clinic, Perumpilly, Mulanthuruthy, Ernakulam - 682 314, Kerala


Management of intermittent exotropia raises several concerns, regarding the indication for surgery, timing of the surgery, and the type of surgical procedure. This article attempts to highlight the controversial aspects of surgical management of intermittent exotropia and the consensus, in light of current evidence.

How to cite this article:
Sathyan S. Concerns in the surgical treatment of intermittent exotropia.Kerala J Ophthalmol 2020;32:87-88

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Sathyan S. Concerns in the surgical treatment of intermittent exotropia. Kerala J Ophthalmol [serial online] 2020 [cited 2020 Jul 13 ];32:87-88
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Full Text

Exotropia is one of the most common types of strabismus in children,[1],[2] especially in Asian populations. Intermittent exotropia X(T) is the most common subtype of exotropia.[2],[3],[4] Despite being a prevalent form of strabismus, the management of intermittent exotropia remains controversial. The natural history of X(T) remains unclear, and many studies have shown that a considerable percentage of patients who were delayed immediate surgery showed improvement in the ocular alignment in the long term.[5],[6],[7] A recent randomized control study concluded that in intermittent exotropes between 3 and 10 years of age, for whom the surgery was not immediately considered, stereoacuity deterioration or progression to constant exotropia over 3 years was uncommon. The study also showed that exotropia control, stereoacuity, and magnitude of deviation remained stable or improved slightly at 3 years.[8] Results of this longitudinal study favor delaying surgical intervention in many cases with X(T) and call for change in practice patterns in the management of X(T).

The second controversy is regarding the assessment of fusional control in cases with X (T). The measurement of the amount of deviation is more or less standardized using prisms. However, determination of the grade of fusional control remains problematic and often results in suboptimal surgical results. The Newcastle score was designed to provide a better guide to assess the control in cases with intermittent exotropia. However, the home control part in Newcastle score is based upon recall by the parents and may be subjective, inaccurate, or biased.[9] Therefore, another score solely based upon office control has been designed.[10] However, in the practical scenario, the decision to operate remains the choice of a surgeon and is difficult to define objectively, unlike the case of esotropias, where the indications are clearer. The choice of methods to assess the fusional control in X(T) needs to be better defined.

The third controversy is regarding the timing of surgery in X(T). The main goals of surgery in intermittent exotropia are to preserve binocularity[11] and to improve psychosocial quality of life.[12],[13],[14],[15],[16],[17] The decision to operate is mainly based on four aspects: increasing angle of exodeviation, deteriorating control of X(T), decrease in stereopsis for near or distance, and quality of life. This problem also adds to the timing of surgery for intermittent exotropia. Early surgery is recommended by some authors to preserve binocularity and to achieve optimum results.[11],[18],[19],[20] Many other surgeons advocate delayed surgery for fear of overcorrections.[21],[22],[23] A few others have concluded that age at surgery does not affect the surgical outcome.[24],[25],[26],[27],[28] The consensus regarding the appropriate age for surgical intervention still remains unanswered.

Planned initial overcorrection in the surgery for X (T) was supported by some studies. They argued that the long-term alignment was better when slight overcorrection is planned and that the overcorrection would resolve within 6 weeks of surgery.[26],[29],[30],[31] However, a few others did not find that overcorrection beneficial.[18],[32]

These controversies in the management of X (T) remain unsettled and lack consensus at the practice level.

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Conflicts of interest

There are no conflicts of interest.


1Chia A, Dirani M, Chan YH, Gazzard G, Au Eong KG, Selvaraj P, et al. Prevalence of amblyopia and strabismus in young Singaporean Chinese children. Invest Ophthalmol Vis Sci 2010;51:3411-7.
2Yu CB, Fan DS, Wong VW, Wong CY, Lam DS. Changing patterns of strabismus: A decade of experience in Hong Kong. Br J Ophthalmol 2002;86:854-6.
3Mohney BG, Huffaker RK. Common forms of childhood exotropia. Ophthalmology 2003;110:2093-6.
4Goseki T, Ishikawa H. The prevalence and types of strabismus, and average of stereopsis in Japanese adults. Jpn J Ophthalmol 2017;61:280-5.
5Rutstein RP, Corliss DA. The clinical course of intermittent exotropia. Optom Vis Sci 2003;80:644-9.
6Chia A, Seenyen L, Long QB. A retrospective review of 287 consecutive children in Singapore presenting with intermittent exotropia. J AAPOS 2005;9:257-63.
7Romanchuk KG, Dotchin SA, Zurevinsky J. The natural history of surgically untreated intermittent exotropia-looking into the distant future. J AAPOS 2006;10:225-31.
8Pediatric Eye Disease Investigator Group, Writing Committee, Mohney BG, Cotter SA, Chandler DL, Holmes JM, et al. Three-year observation of children 3 to 10 years of age with untreated intermittent exotropia. Ophthalmology 2019;126:1249-60.
9Haggerty H, Richardson S, Hrisos S, Strong NP, Clarke MP. The Newcastle Control Score: A new method of grading the severity of intermittent distance exotropia. Br J Ophthalmol 2004;88:233-5.
10Mohney BG, Holmes JM. An office-based scale for assessing control in intermittent exotropia. Strabismus 2006;14:147-50.
11Pratt-Johnson JA, Tillson G. Management of Strabismus and Amblyopia: A Practical Guide. New York, Stuttgart: Thieme; 1994. p. 128.
12Sim B, Yap GH, Chia A. Functional and psychosocial impact of strabismus on Singaporean children. J AAPOS 2014;18:178-82.
13Hatt SR, Leske DA, Liebermann L, Mohney BG, Brodsky MC, Yamada T, et al. Associations between health-related quality of life and the decision to perform surgery for childhood intermittent exotropia. Ophthalmology 2014;121:883-8.
14Hatt SR, Leske DA, Holmes JM. Comparison of quality-of-life instruments in childhood intermittent exotropia. J AAPOS 2010;14:221-6.
15Mojon-Azzi SM, Kunz A, Mojon DS. Strabismus and discrimination in children: Are children with strabismus invited to fewer birthday parties? Br J Ophthalmol 2011;95:473-6.
16Paysse EA, Steele EA, McCreery KM, Wilhelmus KR, Coats DK. Age of the emergence of negative attitudes toward strabismus. J AAPOS 2001;5:361-6.
17Satterfield D, Keltner JL, Morrison TL. Psychosocial aspects of strabismus study. Arch Ophthalmol 1993;111:1100-5.
18Pratt-Johnson JA, Barlow JM, Tillson G. Early surgery in intermittent exotropia. Am J Ophthalmol 1977;84:689-94.
19Abroms AD, Mohney BG, Rush DP, Parks MM, Tong PY. Timely surgery in intermittent and constant exotropia for superior sensory outcome. Am J Ophthalmol 2001;131:111-6.
20Asjes-Tydeman WL, Groenewoud H, van der Wilt GJ. Timing of surgery for primary exotropia in children. Strabismus 2006;14:191-7.
21Edelman PM, Brown MH, Murphree AL, Wright KW. Consecutive esodeviation. Then what? Am Orthopic J 1988;38:111-6.
22Richardson S. When is surgery indicated for distance exotropia? Br Orthoptic J 2001;58:24-9.
23Noorden VG. Some aspects of exotropia. In: Presented at Wilmers Residents' Association. Baltimore: John Hopkins Hospital; 1966.
24Beneish R, Flanders M. The role of stereopsis and early postoperative alignment in long-term surgical results of intermittent exotropia. Can J Ophthalmol 1994;29:119-24.
25Folk ER. Surgical results in intermittent exotropia. AMA Arch Ophthalmol 1956;55:484-7.
26Ing MR, Nishimura J, Okino L. Outcome study of bilateral lateral rectus recession for intermittent exotropia in children. Ophthalmic Surg Lasers 1999;30:110-7.
27Richard JM, Parks MM. Intermittent exotropia. Surgical results in different age groups. Ophthalmology 1983;90:1172-7.
28Stoller SH, Simon JW, Lininger LL. Bilateral lateral rectus recession for exotropia: A survival analysis. J Pediatr Ophthalmol Strabismus 1994;31:89-92.
29Keech RV, Stewart SA. The surgical overcorrection of intermittent exotropia. J Pediatr Ophthalmol Strabismus 1990;27:218-20.
30Koo NK, Lee YC, Lee SY. Clinical study for the undercorrection factor in intermittent exotropia. Korean J Ophthalmol 2006;20:182-7.
31Scott WE, Keech R, Mash AJ. The postoperative results and stability of exodeviations. Arch Ophthalmol 1981;99:1814-8.
32Maruo T, Kubota N, Sakaue T, Usui C. Intermittent exotropia surgery in children: Long term outcome regarding changes in binocular alignment. A study of 666 cases. Binocul Vis Strabismus Q 2001;16:265-70.