title: Laterality of amblyopia.
abstract: OBJECTIVE
  To determine the frequency of unilateral amblyopia in right versus left eyes among children younger than 18 years.
  
  
  METHODS
  Analysis of data collected in randomized clinical trials conducted by the Pediatric Eye Disease Investigator Group.
  
  
  METHODS
  The laterality of the amblyopic eye was analyzed in 2635 subjects younger than 18 years who participated in 9 multicenter prospective, randomized treatment trials. Eligibility criteria for these clinical trials included unilateral amblyopia associated with strabismus, anisometropia, or both, with visual acuity between 20/40 and 20/400. Logistic regression was used to assess the association of baseline and demographic factors with the laterality of amblyopia.
  
  
  RESULTS
  Among subjects with anisometropic amblyopia (with or without strabismus), amblyopia was present more often in left than right eyes, with a relative prevalence of 59% in left eyes (95% confidence interval, 57% to 62%; P < .001 from a test of proportion, 50%). However, among subjects with strabismic-only amblyopia, there was no laterality predilection (relative prevalence of 50% in left eyes; 95% confidence interval, 47% to 54%; P = .94).
  
  
  CONCLUSIONS
  Anisometropic amblyopia, with or without strabismus, occurs more often in left eyes than right eyes. This finding of amblyopia laterality may be related to microtropia, sighting dominance, or other forms of ocular dominance; developmental or neurological factors; laterality in the development of refractive error; or a combination thereof.
authors.affiliation: Zanvyl Krieger Children's Eye Care Center, The Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD, USA. pedig@jaeb.org
authors.forename: Michael
authors.initials: M
authors.lastname: Repka
authors.forename: Kurt
authors.initials: K
authors.lastname: Simons
authors.forename: Raymond
authors.initials: R
authors.lastname: Kraker
mesh_terms: D000293:Adolescent; D000550:Amblyopia / Q000453:epidemiology / Q000503:physiopathology*; D015858:Anisometropia / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D007839:Functional Laterality; D006801:Humans; D015995:Prevalence; D011446:Prospective Studies; D013285:Strabismus / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology
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