title: Development of refractive error and strabismus in children with Down syndrome.
abstract: OBJECTIVE
  To investigate the development of refractive errors and strabismus in a cohort of children with Down syndrome.
  
  
  METHODS
  Data for 55 children with Down syndrome who are participating in this longitudinal study of visual development, first examined by us when aged less than 2 years and on at least two other occasions, were analyzed. Mohindra retinoscopy was used to measure refractive error. Ocular alignment was assessed using the Hirschberg test and, when possible, the cover test.
  
  
  RESULTS
  Despite the high prevalence of large refractive errors in children with Down syndrome, longitudinal data showed that these are not always present in early infancy. Twenty-one (38%) of the children were emmetropic throughout the study. Of the 24 children with a significant refractive error at the outset, only 6 (25%) showed emmetropization. The others retained or increased their refractive errors. The remaining 10 children were emmetropic at the outset, but then had a significant refractive error develop. There is a high prevalence of strabismus in children with Down syndrome (29% of the total group), which cannot be attributed to the presence of hypermetropia or anisometropia.
  
  
  CONCLUSIONS
  The retention or development of infantile refractive errors in many children with Down syndrome indicates a failure of emmetropization. All children were at risk of strabismus whatever the refractive error. The findings have implications for timing of screening programs.
authors.affiliation: Department of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom.
authors.forename: Mary
authors.initials: M
authors.lastname: Cregg
authors.forename: J Margaret
authors.initials: JM
authors.lastname: Woodhouse
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Stewart
authors.forename: Valerie H
authors.initials: VH
authors.lastname: Pakeman
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Bromham
authors.forename: Helen L
authors.initials: HL
authors.lastname: Gunter
authors.forename: Lidia
authors.initials: L
authors.lastname: Trojanowska
authors.forename: Margaret
authors.initials: M
authors.lastname: Parker
authors.forename: William I
authors.initials: WI
authors.lastname: Fraser
mesh_terms: D004314:Down Syndrome / Q000150:complications* / Q000503:physiopathology; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000150:complications* / Q000503:physiopathology; D012307:Risk Factors; D013285:Strabismus / Q000150:complications* / Q000503:physiopathology