Abstract
Purpose :
More than half of visually impaired adults experience severe fatigue, which for many has a profound impact on daily life. To understand whether fatigue is a generic or disease-specific problem in adults with vision loss, the aim was to identify factors that explain fatigue, compared to fatigue in adults with normal sight.
Methods :
In a cross-sectional study, data was collected from patients who were registered at low vision rehabilitation services in the Netherlands (N=247, mean age 57.1±14.3, 62% female) and compared to normally sighted controls (N=233) of which five age-matched random selections were taken (N=151, mean age 55.1±11.5, 71% female). Fatigue was defined as a latent variable with two indicators: “severity” (Fatigue Assessment Scale) and “impact” (Modified Fatigue Impact Scale). Explanatory variables such as sociodemographic and (mental) health-related factors were assessed by telephone (patients) and online (controls). Questionnaire data were prepared with item response theory models. Structural equational models were performed in Mplus to identify paths explaining fatigue in patients and, subsequently, in controls.
Results :
In patients, factors associated directly with fatigue were depression (β=0.723, p<0.001), perceived health (β=-0.158, p=0.004), coping (accommodative coping: ability to adjust personal goals, β=0.116, p=0.030) and somatic comorbidity (β=0.311, p=0.001). The association between self-efficacy and fatigue (β=-0.228, p<0.001) was mediated by depression, coping and perceived health. The association between sleep disorder and fatigue (β=0.656, p<0.001) was mediated by depression and perceived health. Explained variance was 64% in patients, and 58% in controls after removal of sleep disorder. Associations between coping or comorbidity and fatigue were not significant in controls.
Conclusions :
In both samples, depression had the strongest association with fatigue. The associations between perceived health or self-efficacy and fatigue were generic in participants with and without vision loss. In turn, comorbidity, sleep disorders and coping seem to be specific determinants of fatigue in patients with vision loss. These common and specific factors should be addressed in interventions to reduce fatigue. In a future analysis we will focus on the influence of additional vision-specific problems (e.g. glare, cognitive burden, acceptance of vision loss) on fatigue.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.