Validation and application of Catquest-9SF in various populations: A systematic review

Abstract

Cataract is a common cause of reversible blindness. Visual acuity alone is not enough to assess appropriateness for surgery, prioritization, and outcomes. Catquest-9SF questionnaire evaluates patients' self-assessed visual function as related to daily tasks. We summarize and assess the validity of Catquest-9SF as a patient-reported outcome questionnaire to determine its suitability for clinical use. Thirteen studies with sample sizes ranging 102-10,886 (total n = 15,289) undertaken from 2009 to 2018 were included. Catquest-9SF showed unidimensionality, ordered response thresholds, and acceptable precision in all studies. Nine studies had significant mistargeting (range 0.66 to -2.04); the tasks being easy relative to the respondent ability in most studies. Two studies had misfitting items. We conclude Catquest-9SF is a valid and reliable tool to measure visual function in patients with cataract in various populations. Because results can be population specific, it is recommended that Catquest-9SF be validated in a new population before it is incorporated in routine practice.

Keywords: Catquest-9SF; Rasch analysis; cataract; cataract surgery; patient-reported outcome; questionnaire; validation; visual function.