Validation of Catquest-9SF questionnaire in a Chinese cataract population.

PURPOSE: To develop and validate a Chinese version of the Catquest-9SF questionnaire in a cataract population. METHODS: The Catquest-9SF Questionnaire was translated and back translated into Chinese. Preoperative patients were recruited at a tertiary eye hospital and their demographic information and visual acuity were documented. Psychometric properties of the Catquest-9SF, including ordered thresholds, the ability to distinguish between different strata of person ability, absence of misfitting items, unidimentionality, differential item functioning (DIF) and construct validity were tested, using Rasch analysis. RESULTS: A total of 102 patients (100% response rate) were enrolled. The participants'mean age was 70.2 year (SD = 12.1) and 46.9% were female. Rasch analysis showed that this version of the questionnaire had ordered response thresholds and was free of DIF. The items fit a single overall construct and unidimensional by principal components analysis of the residuals. Patients with visual impairment had significantly poorer Rasch scores on the Catquest-9SF (mean change, -2.5, p = 0.035, compared with non-visually impaired patients). CONCLUSION: The Chinese version of Catquest-9SF is a valid and reliable questionnaire for assessing the visual disability outcomes of Chinese patients with cataract, and it may be recommended for routine clinical use