title: Measuring the Quality of Life of Visually Impaired Children: First Stage Psychometric Evaluation of the Novel VQoL_CYP Instrument.
abstract: OBJECTIVE
  To report piloting and initial validation of the VQoL_CYP, a novel age-appropriate vision-related quality of life (VQoL) instrument for self-reporting by children with visual impairment (VI).
  
  
  METHODS
  Participants were a random patient sample of children with VI aged 10-15 years. 69 patients, drawn from patient databases at Great Ormond Street Hospital and Moorfields Eye Hospital, United Kingdom, participated in piloting of the draft 47-item VQoL instrument, which enabled preliminary item reduction. Subsequent administration of the instrument, alongside functional vision (FV) and generic health-related quality of life (HRQoL) self-report measures, to 101 children with VI comprising a nationally representative sample enabled further item reduction and evaluation of psychometric properties using Rasch analysis. Construct validity was assessed through Pearson correlation coefficients.
  
  
  RESULTS
  Item reduction through piloting (8 items removed for skewness and individual item response pattern) and validation (1 item removed for skewness and 3 for misfit in Rasch) produced a 35-item scale, with fit values within acceptable limits, no notable differential item functioning, good measurement precision, ordered response categories and acceptable targeting in Rasch. The VQoL_CYP showed good construct validity, correlating strongly with HRQoL scores, moderately with FV scores but not with acuity.
  
  
  CONCLUSIONS
  Robust child-appropriate self-report VQoL measures for children with VI are necessary for understanding the broader impacts of living with a visual disability, distinguishing these from limited functioning per se. Future planned use in larger patient samples will allow further psychometric development of the VQoL_CYP as an adjunct to objective outcomes assessment.
authors.affiliation: Population, Policy and Practice Programme, Life Course Epidemiology and Biostatistics Section, University College London (UCL) Institute of Child Health, London, United Kingdom (United Kingdom).|Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom.
authors.forename: Valerija
authors.initials: V
authors.lastname: Tadić
authors.affiliation: Department of Psychology, Goldsmiths, University of London, London, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cooper
authors.affiliation: Population, Policy and Practice Programme, Life Course Epidemiology and Biostatistics Section, University College London (UCL) Institute of Child Health, London, United Kingdom (United Kingdom).|Ulverscroft Vision Research Group, London, United Kingdom.
authors.forename: Phillippa
authors.initials: P
authors.lastname: Cumberland
authors.affiliation: Warwick Medical School, University of Warwick, Coventry, United Kingdom.
authors.forename: Gillian
authors.initials: G
authors.lastname: Lewando-Hundt
authors.affiliation: Population, Policy and Practice Programme, Life Course Epidemiology and Biostatistics Section, University College London (UCL) Institute of Child Health, London, United Kingdom (United Kingdom).|National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom.|Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom.|Ulverscroft Vision Research Group, London, United Kingdom.
authors.forename: Jugnoo S
authors.initials: JS
authors.lastname: Rahi
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D008131:London; D008297:Male; D010865:Pilot Projects; D011594:Psychometrics / Q000379:methods* / Q000706:statistics & numerical data; D011788:Quality of Life; D057566:Self Report; D014786:Vision Disorders / Q000523:psychology*; D019987:Persons with Visual Disabilities / Q000523:psychology / Q000706:statistics & numerical data