Impaired visual attention and numerical processing in children with anisometropic amblyopia and after visual acuity recovery

Amblyopia affects more than visual acuity. To compare the performances of visual selective attention and numerical processing in children with anisometropic amblyopia and children with normal vision, and investigate whether performance would be improved after visual acuity recovery, we performed 3 visual attention tasks (identifying number location task, numerical comparison task, and specific number comparison task) in children with anisometropic amblyopia, children who had recovered from anisometropic amblyopia, and children with normal vision in 6-8 and 9-11 years groups. The numerical processing ability, visual selective attention, and numerical distance effect were assessed by their reaction time of different tasks. The amblyopia group showed significantly worse visual selective attention than control group. However, the recovered amblyopic group showed worse visual selective attention compared to control group only in 9-11 years group. Children aged 6-8 had a greater numerical distance effect than 9-11 in control group, while there were no significant differences between different age groups in amblyopia and recovered amblyopic children. These findings suggest children with anisometropic amblyopia have not only defective visual selective attention but also different age-related patterns of numerical distance effect. Moreover, the improvement of visual selective attention after early stage of visual acuity recovery is better at younger age.