Shape of magnifiers affects controllability in children with visual impairment.
OBJECTIVE
This study aimed to examine the controllability of cylinder-shaped and dome-shaped magnifiers in young children with visual impairment.


METHODS
This 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 4-8 years executed two types of movements (cyclic and discrete) in two orientations (vertical or horizontal) over two distances (10 cm and 20 cm) with two objects resembling the size and shape of regularly prescribed stand and dome magnifiers.


RESULTS
The 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 10 cm condition and 20 cm condition with discrete movements) and more accurate (in the 20 cm condition) than with the stand-shaped object.


CONCLUSIONS
From a controllability perspective, this study suggests that it is better to prescribe dome-shaped than cylinder-shaped magnifiers to young children with visual impairment.
Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.|Bartiméus, Institute for the Visually Impaired, Zeist, The Netherlands.
Joyce
J
Liebrand-Schurink
Bartiméus, Institute for the Visually Impaired, Zeist, The Netherlands.|Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
F Nienke
FN
Boonstra
VU Medical Centre Amsterdam, Amsterdam, The Netherlands.
Ger H M B
GH
van Rens
Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.
Antonius H N
AH
Cillessen
Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
Ruud G J
RG
Meulenbroek
Department of Developmental Psychology, University of Groningen, Groningen, The Netherlands.
Ralf F A
RF
Cox
D002648:Child; D002675:Child, Preschool; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D009885:Ophthalmology / Q000295:instrumentation*; D011597:Psychomotor Performance / Q000502:physiology*; D011932:Reading; D012682:Sensory Aids; D015354:Vision, Low / Q000503:physiopathology* / Q000534:rehabilitation*; D014792:Visual Acuity / Q000502:physiology; D019987:Persons with Visual Disabilities / Q000534:rehabilitation*
accuracy; children; controllability; low-vision aids; magnifier; speed; visual impairment