Author(s): Khadka J, Ryan B, Margrain TH, Court H, Woodhouse JM, Khadka J, Ryan B, Margrain TH, Court H, Woodhouse JM
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Abstract 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.
This article was published in Br J Ophthalmol
and referenced in Optometry: Open Access