Development and validation of the 21-item Children’s Vision for Living Scale (CVLS) by Rasch analysis
Bokhary, Kholoud . 2013
Background: The aim was to develop and validate an instrument called the ‘Children’s
Vision for Living Scale’ (CVLS) for the assessment of vision-related quality of life in Saudi
Arabian children with and without amblyopia.
Methods: A 43-item child self-report questionnaire was initially developed based on interviews
with children with amblyopia, their parents and eye-care professionals, and a literature
review. Following a process that involved the removal of redundant items, 28 items remained
and were piloted on children aged five to 12 years with and without amblyopia (n = 48
amblyopic, n = 53 non-amblyopic) living in Saudi Arabia. Rasch analysis was applied to
determine whether the 28-item questionnaire fitted the Rasch model. Rasch analysis was
used to assess the validity and reliability of the questionnaire. Principal components analysis
(PCA) was used to check dimensionality. A 21-item questionnaire resulting from this process
was administered in children with (n = 81) and without (n = 82) amblyopia in Saudi Arabia
for further validation.
Results: The final 21-item questionnaire had good validity and reliability as demonstrated
by person separation of 2.02, person reliability of 0.80 (mean square and standard deviation:
infit = 1.01 0.39; outfit = 1.01 0.40) and item reliability of 0.93 (item infit range = 1.33
to 0.78; item outfit range = 0.78 to 1.30). The mean difference between person and item
scores of 0.33 0.53 logits (scale range, 2 to -2) indicates that the items are well targeted to
the populations. The PCA (dimensionality measures) shows the percentage of variance
explained by measures equal to 26.4 per cent (modelled 26.9 per cent) and an eigenvalue of
the first contrast of 2.5, which demonstrated good stability.
Conclusion: The 21-item CVLS is a valid uni-dimensional child self-report instrument for
the assessment of the impact of amblyopia on vision-related quality of life in children with
and without amblyopia living in Saudi Arabia.
Background: The aim was to develop and validate an instrument called the ‘Children’s
Vision for Living Scale’ (CVLS) for the assessment of vision-related quality of life in Saudi
…