Abstract
Purpose :
Compared to people without vision loss, people with visual impairment (VI) often experience severe symptoms of fatigue which impact activities of daily living. Previously, we found that depression was strongly associated with fatigue. In addition to VI severity, we investigated which other factors related to the VI are also associated with fatigue.
Methods :
In a cross-sectional study, we collected questionnaire data among 220 Dutch low vision service patients. Measured constructs were fatigue (Fatigue Assessment Scale, Modified Fatigue Impact Scale), vision-related mobility (Low Vision Quality of Life subscale) and vision-specific symptoms (latent variable eye-strain & light disturbance), depression (Patient Health Questionnaire) and adaptation to vision loss (AVL-9) which were analyzed using item response theory. To test (in)direct effects of VI severity (mild/moderate, severe, blindness) on fatigue, we investigated whether abovementioned variables mediated the association, using structural equational modeling in Mplus.
Results :
People with severe VI (reference group) experienced a significantly higher severity and impact of fatigue compared to those with mild/moderate VI (c1: β=-0.50, 95% bias-corrected confidence interval [BC CI] [-0.86, -0.16]) or blindness (c2: β=-0.44, 95% BC CI [-0.80, -0.07]). Vision-specific symptoms and depression mediated the association between the two vision loss severity comparisons and fatigue. Vision-related mobility was only identified as a mediator between the mild/moderate and severe VI contrast in the association with fatigue. Moreover, depression (β=0.65, p<0.001) and vision-specific symptoms (β=0.19, p=0.023) were directly associated with fatigue, independent of VI severity. AVL was not predictive of fatigue while controlling for the other variables in the model. The final model explained 60% of the variance.
Conclusions :
The association between VI severity and fatigue shows an inverted-U shape. The complexity of this relationship is partly explained by the consequences of VI, in particular by vision-related problems such as eye strain and light disturbance, mobility problems and depressed mood, but also by the severity of the disability itself, where blindness and its impact on vision-specific symptoms seem to mitigate fatigue symptoms.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.