The following is a summary of “Multiple mediating effects of vision-specific factors and depression on the association between visual impairment severity and fatigue: a path analysis study,” published in the August 2024 issue of Psychiatry by Schakel et al.

Severe fatigue is the most common symptom in individuals with visual impairment, emotional functioning, cognition, work capacity, and daily activities. Among these, depression is one of the significant determinants of fatigue. 

Researchers conducted a retrospective study to explore the association between visual impairment severity and fatigue in adults with low vision. They investigated direct and indirect relationships, considering vision-specific factors and depression as potential mediators.

They collected data from 220 Dutch individuals with low vision by telephone interviews. Fatigue was defined as a latent variable based on severity and impact on daily life. Potential mediators included vision-related symptoms, adaptation to vision loss, and depression. Hypothesized structural equation models were constructed in Mplus to test (in) direct effects of visual impairment severity (mild/moderate, severe, blindness) on fatigue through the variables mentioned above.

The result showed a 60% variance in fatigue and revealed an effect of visual impairment severity on fatigue. Patients with severe visual impairment had significantly higher fatigue symptoms compared to those with mild/moderate visual impairment (β=-0.50, 95% bias-corrected confidence interval [BC CI] [-0.86, -0.16]) and those with blindness (β=-0.44, 95% BC CI [-0.80, -0.07]). Eye strain & light disturbance, depression, and vision-related mobility mediated the fatigue difference between the severe and mild/moderate visual impairment categories. The fatigue difference between the severe visual impairment and blindness categories was solely explained by eye strain & light disturbance. Moreover, depressive symptoms (β=0.65, P < 0.001) and eye strain & light disturbance (β=0.19, P= 0.023) were directly associated with fatigue independent of visual impairment severity.

They concluded with certainty an inverted-U-shaped relationship between visual impairment severity and fatigue in patients with low vision. 

Source: bmcpsychiatry.biomedcentral.com/articles/10.1186/s12888-024-06014-5#Abs1