title: Profile of refractive errors in cerebral palsy: impact of severity of motor impairment (GMFCS) and CP subtype on refractive outcome.
abstract: OBJECTIVE
  To describe refractive status in children and young adults with cerebral palsy (CP) and relate refractive error to standardized measures of type and severity of CP impairment and to ocular dimensions.
  
  
  METHODS
  A population-based sample of 118 participants aged 4 to 23 years with CP (mean 11.64 +/- 4.06) and an age-appropriate control group (n = 128; age, 4-16 years; mean, 9.33 +/- 3.52) were recruited. Motor impairment was described with the Gross Motor Function Classification Scale (GMFCS), and subtype was allocated with the Surveillance of Cerebral Palsy in Europe (SCPE). Measures of refractive error were obtained from all participants and ocular biometry from a subgroup with CP.
  
  
  RESULTS
  A significantly higher prevalence and magnitude of refractive error was found in the CP group compared to the control group. Axial length and spherical refractive error were strongly related. This relation did not improve with inclusion of corneal data. There was no relation between the presence or magnitude of spherical refractive errors in CP and the level of motor impairment, intellectual impairment, or the presence of communication difficulties. Higher spherical refractive errors were significantly associated with the nonspastic CP subtype. The presence and magnitude of astigmatism were greater when intellectual impairment was more severe, and astigmatic errors were explained by corneal dimensions. Conclusions. High refractive errors are common in CP, pointing to impairment of the emmetropization process. Biometric data support this
  
  
  CONCLUSIONS
  In contrast to other functional vision measures, spherical refractive error is unrelated to CP severity, but those with nonspastic CP tend to demonstrate the most extreme errors in refraction.
authors.affiliation: Vision Science Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, United Kingdom.
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Saunders
authors.forename: Julie-Anne
authors.initials: JA
authors.lastname: Little
authors.forename: Julie F
authors.initials: JF
authors.lastname: McClelland
authors.forename: A Jonathan
authors.initials: AJ
authors.lastname: Jackson
mesh_terms: D000293:Adolescent; D001699:Biometry; D002547:Cerebral Palsy / Q000145:classification / Q000453:epidemiology / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D019957:Motor Skills Disorders / Q000145:classification / Q000453:epidemiology / Q000503:physiopathology*; D009660:Northern Ireland; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000145:classification / Q000453:epidemiology / Q000503:physiopathology*; D012042:Registries; D042262:Retinoscopy; D012720:Severity of Illness Index; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult