The impact of vision impairment on vision-specific quality of life in Germany.

PURPOSE: To validate the German-translated Impact of Vision Impairment (IVI) questionnaire, a vision-specific quality of life (QoL) scale, and determine the relationship between the severity of vision impairment, ocular conditions, and VRQoL.
METHODS: This cross-sectional study was clinic based, with 184 patients with low vision recruited from an outpatient clinic at a German eye hospital. Participants underwent a clinical examination and completed the German IVI scale. The validity of the IVI scale was assessed using Rasch analysis. The main outcome measure was the overall functional and emotional score provided by the IVI.
RESULTS: Overall, there were more female (n = 111, 60.3%) than male participants. Participants' mean ± SD age and visual acuity in the better eye were 69.0 ± 15.5 years and. 0.41 ± 0.35 logMAR, respectively. The main cause of vision loss was age-related macular degeneration (n = 54, 29.3%). Rasch analysis demonstrated the validity of the German IVI to assess VRQoL through two subscales: vision-specific functioning and emotional well-being. In adjusted multivariate analysis models, those with mild or moderate/severe vision impairment reported significantly poorer vision-specific functioning (mean change, -6.5, P = 0.018 and -11.98, P < 0.001 for mild and moderate to severe VI, respectively) and emotional well-being (mean change, -2.35; P = 0.043 and -3.13, P = 0.004 for mild and moderate/severe VI respectively) compared with non-visually impaired patients.
CONCLUSIONS: Using a psychometrically valid German IVI, even mild vision impairment was independently associated with poor VRQoL. These findings reinforce the importance of early preventative and rehabilitative efforts to prevent longitudinal deterioration in vision loss.