Shape of magnifiers affects controllability in children with visual impairment

PurposeThis study aimed to examine the controllability of cylinder-shaped and dome-shaped magnifiers in young children with visual impairment.MethodsThis study investigates goal-directed arm movements in low-vision aid use (stand and dome magnifier-like object) in a group of young children with visual impairment (n=56) compared to a group of children with normal sight (n=66). Children with visual impairment and children with normal sight aged 4-8years executed two types of movements (cyclic and discrete) in two orientations (vertical or horizontal) over two distances (10cm and 20cm) with two objects resembling the size and shape of regularly prescribed stand and dome magnifiers.ResultsThe visually impaired children performed slower movements than the normally sighted children. In both groups, the accuracy and speed of the reciprocal aiming movements improved significantly with age. Surprisingly, in both groups, the performance with the dome-shaped object was significantly faster (in the 10cm condition and 20cm condition with discrete movements) and more accurate (in the 20cm condition) than with the stand-shaped object.ConclusionFrom a controllability perspective, this study suggests that it is better to prescribe dome-shaped than cylinder-shaped magnifiers to young children with visual impairment.