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Development of the 25-item Cardiff Visual Ability Questionnaire for Children (CVAQC)
  1. Jyoti Khadka,
  2. Barbara Ryan,
  3. Tom H Margrain,
  4. Helen Court,
  5. J Margaret Woodhouse
  1. School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
  1. Correspondence to Dr J Margaret Woodhouse, School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4LU, UK; woodhouse{at}


Aims To develop and validate a short questionnaire to assess self-reported visual ability in children and young people with a visual impairment.

Methods A list of 121 items was generated from 13 focus groups with children and young people with and without a visual impairment. A long 89-item questionnaire was piloted with 45 visually impaired children and young people using face-to-face interviews. Rasch analysis was used to analyse the response category function and to facilitate item removal ensuring a valid unidimensional scale. The validity and reliability of the short questionnaire were assessed on a group of 109 visually impaired children (58.7% boys; median age 13 years) using Rasch analysis and intraclass correlation coefficient (ICC).

Results The final 25-item questionnaire has good validity and reliability as demonstrated by a person separation index of 2.28 and reliability coefficient of 0.84. The items are well targeted to the subjects with a mean difference of −0.40 logit between item and person means, and an ICC of 0.89 demonstrates good temporal stability.

Conclusion The Cardiff Visual Ability Questionnaire for Children (CVAQC) is a short, psychometrically robust and a self-reported instrument that works to form a unidimensional scale for the assessment of the visual ability in children and young people with a visual impairment.

  • Child health (paediatrics)
  • children and young people
  • intraclass correlation coefficient
  • low vision aid, questionnaire
  • Rasch analysis
  • visual impairment
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  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval All the procedures adhered to the tenets of the Declaration of Helsinki. Ethics approval was obtained separately for the focus groups, pilot and the main study for validity assessment from the School Human Research Ethical Committee at Cardiff University.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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