Assessment of cataract surgery outcome using the modified catquest short-form instrument in China

Purpose: To assess cataract surgery outcome using the Rasch scaled Chinese version of the Catquest short-form. Methods: The Chinese translated and culturally adapted version of the Catquest-9SF was interviewer-administered to patients, pre and post cataract surgery. Rasch analysis was performed on the baseline data to revise the Catquest. For the surgical outcome assessment, we stacked pre- and post-surgical Catquest data to demonstrate improvement in visual function scores and responsiveness of the instrument to cataract surgery. Results: A total of 247 cataract patients (median age, 70 yrs; male 51.0%) completed the Catquest 9SF at baseline.The Catquest-9SF possessed adequate measurement precision of 2.15. No disordering of response categories were observed and all the items perfectly fit to the Rasch model except item 7 (outfit >1.5). A slight reduction in precision was observed after removing misfitting item 7 (Catquest-8SF-CN), but the precision value was well above the acceptable value of 2.00. Notably, the instrument was well targeted (mean person location 0.30), demonstrated no evidence of multidimensionality and DIF. At 12 months post-surgery, 74 (30%) patients came for follow-up and completed the Catquest. There was a significant improvement in the Catquest scores post cataract surgery with a considerably large effect size. Conclusion: The Catquest-8SF-CN demonstrated promising Rasch based psychometric properties and was highly responsive to cataract surgery.