The refractive status and vision profile: Rasch analysis of subscale validity

Vijaya Gothwal, Thomas Wright, David Elliott, Konrad Pesudovs

    Research output: Contribution to journalArticle

    14 Citations (Scopus)

    Abstract

    PURPOSE: To determine whether the eight subscales of the Refractive Status and Vision Profile (RSVP) questionnaire provide valid measurement. METHODS: Two hundred patients, recruited from a refractive surgery clinic and general optometric practice, self-administered the 42-item RSVP questionnaire. Psychometric properties investigated included measurement of a single construct (unidimensionality), item fit to construct, measurement precision (represented by person separation), targeting of item difficulty to patient's quality of life (QOL), and differential item functioning. RESULTS: Only two subscales ("concern" and "driving") showed adequate person separation, indicating that they could discriminate patients' QOL. However, both demonstrated poor targeting (7.02 logits for "driving" and 1.11 logits for "concern"). One-third of items in each subscale suffered from differential item functioning. CONCLUSIONS: None of the RSVP subscales are valid for assessment of QOL in patients with refractive error, thereby indicating the RSVP should be considered as a single questionnaire without subscales.

    Original languageEnglish
    Pages (from-to)912-915
    Number of pages4
    JournalJournal of Refractive Surgery
    Volume26
    Issue number11
    DOIs
    Publication statusPublished - 1 Nov 2010

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