Fig. 1

Three boxplots show the significant interdependence between the absolute number of caring hours per week and the visual acuity (Kruskal-Wallis p-value <0.01). A visual acuity of >0.3 caused on average 4.3 ± 4.4, a visual acuity of ≤0.3 - >0.1 caused on average 5.6 ± 5.9 and a visual acuity of ≤0.1 caused on average 11.9 ± 14.2 caring hours per week