You are in: eMedicine Specialties > Ophthalmology > EXTRAOCULAR MUSCLES Exotropia, CongenitalArticle Last Updated: Oct 31, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: Mounir Bashour, MD, CM, FRCS(C), PhD, FACS, Assistant Professor of Ophthalmology, McGill University; Clinical Assistant Professor of Ophthalmology, Sherbrooke University; Medical Director, Cornea Laser and Lasik MD Mounir Bashour is a member of the following medical societies: American Academy of Ophthalmology, American Association for Pediatric Ophthalmology and Strabismus, American College of International Physicians, American College of Surgeons, American Medical Association, American Society of Cataract and Refractive Surgery, American Society of Mechanical Engineers, American Society of Ophthalmic Plastic and Reconstructive Surgery, Biomedical Engineering Society, Canadian Medical Association, Canadian Ophthalmological Society, Contact Lens Association of Ophthalmologists, International College of Surgeons US Section, Ontario Medical Association, Quebec Medical Association, and Royal College of Physicians and Surgeons of Canada Coauthor(s): C Corina Gerontis, MD, Consulting Staff, Departments of Pediatrics and Ophthalmology, Schneider Children's Hospital/Long Island Jewish Medical Center Editors: Gerhard W Cibis, MD, Clinical Professor, Director of Pediatric Ophthalmology Service, Department of Ophthalmology, University of Kansas, Kansas City; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; J James Rowsey, MD, Former Director of Corneal Services, St Luke's Cataract and Laser Institute, Florida; Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri; Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences Author and Editor Disclosure Synonyms and related keywords: congenital exotropia, XT, strabismus INTRODUCTIONSection 2 of 9
  BackgroundThe 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.1 In their study, they evaluated differences between infants, aged younger than 1 year, with constant exotropia versus intermittent exotropia at presentation.1 They found that "half of infantile exotropia patients may present with intermittent exotropia, with similar clinical outcomes regardless of presentation."1 In their study, surgical intervention resulted in successful alignment in most cases.1 More than half the patients developed measurable stereopsis, but none achieved bifixation.1 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.2 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. PathophysiologyThe pathophysiology is unknown, although strabismus does occur in families, suggesting a multifactorial autosomal dominant pattern with incomplete penetrance. FrequencyUnited StatesCongenital exotropia is extremely rare in the United States. InternationalThe worldwide incidence of congenital exotropia is unknown. Mortality/MorbidityThere is a higher incidence of amblyopia in congenital exotropia than in other forms of exotropia. RaceNo known racial predisposition to congenital exotropia exists. SexNo known sexual predilection exists. AgeCongenital 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. CLINICALSection 3 of 9
HistoryBy definition, children present when they are younger than 12 months with a constant outward deviation of the eyes. Physical
CausesThere is a familial predisposition suggestive of an autosomal dominant pattern with incomplete penetrance. DIFFERENTIALSSection 4 of 9
Exotropia, Acquired Oculomotor Nerve Palsy
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