The impact of vision impairment questionnaire: An assessment of its domain structure using confirmatory factor analysis and rasch analysis

Abstract

PURPOSE. To assess and validate the subscale structure of the 28-item Impact of Visual Impairment (IVI) Scale by using confirmatory factor analysis (CFA) and Rasch analysis for use as an outcome measure. METHODS. Three hundred nineteen participants completed the IVI questionnaire, and the responses then were subjected to Rasch analysis by RUMM2020 software. With the person estimates for each item, CFA was used to assess two hypothesized structures: three-and four-factor models. The subscales of the model with the best fit were then further validated by Rasch analysis. RESULTS. CFA supported a three-factor model that included items from the emotional well-being, reading and accessing informat..