title: Translation, cultural adaptation, and Rasch analysis of the visual function (VF-14) questionnaire.
abstract: OBJECTIVE
  To translate, culturally adapt, and validate the original and previously validated shorter versions of the Visual Function Index (VF-14) questionnaire in a Chinese population.
  
  
  METHODS
  The VF-14 was completed by patients with cataract. The analysis was carried out in three phases: phase I, testing whether the VF-14 and its valid shorter versions,VF-8R and VF-11R, form valid scales in Chinese settings using Rasch analysis; phase II, developing completely new Chinese versions of the VF-14; phase III, testing whether the previously validated shorter versions of the VF-14 could be applied in a Chinese population. This was tested by assessing the agreement between the new Chinese (developed in phase II) and the previously validated shorter versions of the VF-14 using Bland-Altman plots.
  
  
  RESULTS
  A total of 456 patients (median age, 70 years; range, 40-92 years; females, 58%) completed the Chinese translated version of the VF-14. The VF-14 and the VF-11R demonstrated good Rasch based psychometric properties when a grossly misfitting item was removed. The VF-8R formed a valid scale without any modification. The scores of the VF-11R and the Chinese shorter version (VF-11RChin) showed very good agreement, with a mean difference of -0.18 logits and 95% limits of agreement between 0.11 and -0.47.
  
  
  CONCLUSIONS
  The Chinese translated VF-14, VF-11R, and VF-8R were valid and could be applied to assess cataract outcomes in Chinese settings. The existing shorter version had good agreement with the new Chinese version, which signifies that there was no need to develop a different version of the VF-14 in China.
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China National Health and Medical Research Council Centre for Clinical Eye Research, Discipline of Optometry and Vision Science, Flinders University of South Australia, Bedford Park, South Australia, Australia.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Khadka
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Jinhai
authors.initials: J
authors.lastname: Huang
authors.affiliation: St. Erik Eye Hospital, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Kaziwe
authors.initials: K
authors.lastname: Mollazadegan
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Gao
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Haisi
authors.initials: H
authors.lastname: Chen
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Sifang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Qinmei
authors.initials: Q
authors.lastname: Wang
authors.affiliation: National Health and Medical Research Council Centre for Clinical Eye Research, Discipline of Optometry and Vision Science, Flinders University of South Australia, Bedford Park, South Australia, Australia.
authors.forename: Konrad
authors.initials: K
authors.lastname: Pesudovs
mesh_terms: D000223:Adaptation, Psychological / Q000502:physiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000453:epidemiology* / Q000523:psychology / Q000534:rehabilitation; D002681:China / Q000453:epidemiology; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D014175:Translating; D014785:Vision, Ocular
keywords: Rasch analysis; VF-14; cross-cultural validation; patient-reported outcomes; psychometric properties