Calibrating the Impact of Vision Impairment (IVI): Creation of a Sample-Independent Visual Function Measure for Patient-Centered Outcomes Research.

ABSTRACT:

Purpose

Provide item calibrations estimated for the Impact of Vision Impairment (IVI) questionnaire by pooling data from several studies of people with vision impairment (VI) representing a variety of countries and causes of VI.

Methods

Eight data sets from six principal investigators representing responses to IVI items from 2867 VI patients were pooled for analysis. Eligible patients were 18 years or older and from Australia, India, and the United States. Rasch analysis, using the Andrich Rating Scale Model (Winsteps version 3.65), was performed on preintervention IVI responses to estimate item and person measures, reliability coefficients, and response category thresholds. Differential item functioning (DIF) analysis and analysis of variance (ANOVA) were used to examine th

SUBMITTER: Goldstein JE 

PROVIDER: S-EPMC6314226 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature