- Author: Mounir Bashour, MD, PhD, CM, FRCSC, FACS; Chief Editor: Hampton Roy, Sr, MD more...
The term congenital exotropia is typically reserved for patients presenting in the first year of life with a large, constant angle.
However, as Hunter et al (2001) state, no published study provides a rationale for this restrictive definition. In their study, they evaluated differences between infants, aged younger than 1 year, with constant exotropia versus intermittent exotropia at presentation. They found that "half of infantile exotropia patients may present with intermittent exotropia, with similar clinical outcomes regardless of presentation." In their study, surgical intervention resulted in successful alignment in most cases. More than half the patients developed measurable stereopsis, but none achieved bifixation.
In a 2008 study of 12 patients with intermittent exotropia treated with bilateral lateral rectus recession, stereoacuity, as seen in the late follow-up period, measured at 40 arcsec in 2 patients, 100 arcsec in 3 patients, 140-400 arcsec in 2 patients, and none in 5 patients.
True congenital exotropia (with a fixed exotropia) is an extremely rare form of strabismus and may occur with systemic disease in as many as 60% of patients. Patients with craniofacial syndromes, ocular albinism, midline defects, and cerebral palsy may present with congenital exotropia.
See related CME at Highlights of the American Association for Pediatric Ophthalmology and Strabismus Annual Meeting.
The pathophysiology is unknown, although strabismus does occur in families, suggesting a multifactorial autosomal dominant pattern with incomplete penetrance.
A good recent review of risk factors and genetics in common comitant strabismus can be found here.
Congenital exotropia is extremely rare in the United States.
The worldwide incidence of congenital exotropia is unknown.
There is a higher incidence of amblyopia in congenital exotropia than in other forms of exotropia.
No known racial predisposition to congenital exotropia exists.
No known sexual predilection exists.
Congenital exotropia presents in infants younger than 6 months. Children who are born premature are at higher risk of developing strabismus; however, congenital exotropia does not occur at a higher rate in premature children.
Hunter DG, Kelly JB, Buffenn AN, et al. Long-term outcome of uncomplicated infantile exotropia. J AAPOS. 2001 Dec. 5(6):352-6. [Medline].
Saunders RA, Trivedi RH. Sensory results after lateral rectus muscle recession for intermittent exotropia operated before two years of age. J AAPOS. 2008 Apr. 12(2):132-5. [Medline].
Maconachie GD, Gottlob I, McLean RJ. Risk factors and genetics in common comitant strabismus: a systematic review of the literature. JAMA Ophthalmol. 2013 Sep. 131(9):1179-86. [Medline].
Kim E, Kim JH, Hwang JM, Choi BS, Jung C. MR Imaging of Congenital or Developmental Neuropathic Strabismus: Common and Uncommon Findings. AJNR Am J Neuroradiol. 2012 May 17. [Medline].
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Matsuo T, Yamane T, Ohtsuki H. Heredity versus abnormalities in pregnancy and delivery as risk factors for different types of comitant strabismus. J Pediatr Ophthalmol Strabismus. 2001 Mar-Apr. 38(2):78-82. [Medline].
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von Noorden GK. Binocular Vision and Binocular Motility: Theory and Management of Strabismus. 1996.
Wright KW, Buckley EG, Del Monte MA. Pediatric Ophthalmology and Strabismus. 1995.