Assessing participation in daily living and the effectiveness of rehabiliation in age related macular degeneration patients using the impact of vision impairment scale

Abstract

Purpose: To assess if the Impact of Vision Impairment (IVI) is a valid instrument to measure participation in daily activities and rehabilitation in patients with age-related macular degeneration (AMD) and varying levels of visual impairment. Methods: Participants, recruited from a public eye hospital and low vision centers, completed the IVI questionnaire. The IVI and its three subscales were assessed for fit to the Rasch model. Unidimensionality, item fit, response category performance, and targeting of items to patients were assessed. Confirmatory factor analysis (CFA) was used to assess the three-factor model of the IVI in this sample of AMD patients. Results: 219 patients (mean ± SD age..