Visual Activities Questionnaire: Assessment of subscale validity for cataract surgery outcomes

Abstract

Purpose: To examine the psychometric properties of the Visual Activities Questionnaire (VAQ) and each of its subscales in a modern cataract population using Rasch analysis and if flawed, to revise the VAQ and create a valid measure that maximizes its measurement properties. Setting: Flinders Eye Centre, Flinders Medical Centre, Adelaide, Australia. Methods: Patients with cataract in 1 or both eyes drawn from the surgical waiting list were mailed the 33-item VAQ for self-administration. The following were examined for the entire questionnaire and each subscale: whether items measured a single construct (unidimensionality), the behavior of response categories, the ability to differentiate betw..