title: Development of the functional vision questionnaire for children and young people with visual impairment: the FVQ_CYP.
abstract: OBJECTIVE
  To develop a novel age-appropriate measure of functional vision (FV) for self-reporting by visually impaired (VI) children and young people.
  
  
  METHODS
  Questionnaire development.
  
  
  METHODS
  A representative patient sample of VI children and young people aged 10 to 15 years, visual acuity of the logarithm of the minimum angle of resolution (logMAR) worse than 0.48, and a school-based (nonrandom) expert group sample of VI students aged 12 to 17 years.
  
  
  METHODS
  A total of 32 qualitative semistructured interviews supplemented by narrative feedback from 15 eligible VI children and young people were used to generate draft instrument items. Seventeen VI students were consulted individually on item relevance and comprehensibility, instrument instructions, format, and administration methods. The resulting draft instrument was piloted with 101 VI children and young people comprising a nationally representative sample, drawn from 21 hospitals in the United Kingdom. Initial item reduction was informed by presence of missing data and individual item response pattern. Exploratory factor analysis (FA) and parallel analysis (PA), and Rasch analysis (RA) were applied to test the instrument's psychometric properties.
  
  
  METHODS
  Psychometric indices and validity assessment of the Functional Vision Questionnaire for Children and Young People (FVQ_CYP).
  
  
  RESULTS
  A total of 712 qualitative statements became a 56-item draft scale, capturing the level of difficulty in performing vision-dependent activities. After piloting, items were removed iteratively as follows: 11 for high percentage of missing data, 4 for skewness, and 1 for inadequate item infit and outfit values in RA, 3 having shown differential item functioning across age groups and 1 across gender in RA. The remaining 36 items showed item fit values within acceptable limits, good measurement precision and targeting, and ordered response categories. The reduced scale has a clear unidimensional structure, with all items having a high factor loading on the single factor in FA and PA. The summary scores correlated significantly with visual acuity.
  
  
  CONCLUSIONS
  We have developed a novel, psychometrically robust self-report questionnaire for children and young people-the FVQ_CYP-that captures the functional impact of visual disability from their perspective. The 36-item, 4-point unidimensional scale has potential as a complementary adjunct to objective clinical assessments in routine pediatric ophthalmology practice and in research.
authors.affiliation: Medical Research Council Centre of Epidemiology for Child Health, Centre for Paediatric Epidemiology and Biostatistics, University College London Institute of Child Health, London, United Kingdom; Ulverscroft Vision Research Group, 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: Medical Research Council Centre of Epidemiology for Child Health, Centre for Paediatric Epidemiology and Biostatistics, University College London Institute of Child Health, London, United Kingdom; Great Ormond Street Hospital for Children NHS Foundation Trust, 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: Medical Research Council Centre of Epidemiology for Child Health, Centre for Paediatric Epidemiology and Biostatistics, University College London Institute of Child Health, London, United Kingdom; National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and University College London 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. Electronic address: j.rahi@ucl.ac.uk.
authors.forename: Jugnoo S
authors.initials: JS
authors.lastname: Rahi
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D001766:Blindness / Q000503:physiopathology*; D002648:Child; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D011594:Psychometrics; D011788:Quality of Life; D057566:Self Report; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D006113:United Kingdom; D015354:Vision, Low / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*; D019987:Persons with Visual Disabilities