Deficits of spatial localization in children with strabismic amblyopia.
BACKGROUND
Besides loss of visual acuity and binocularity, spatial localization deficits (comprising both increased spatial uncertainty and spatial distortions) are an important feature of strabismic amblyopia. Although they have been extensively investigated in adult amblyopes, there are still many open questions concerning their substrate and relationship to clinical parameters. Our aim was to develop a procedure for assessing vertical alignment, which enabled us to find out whether children with strabismic amblyopia had similar spatial localization deficits, and their relation to the children's clinical condition.


METHODS
Vertical alignment was assessed in children by comparing the visual direction in space of three loci along the vertical meridian, separated by 5 deg of visual angle. We tested alignment in the amblyopic and dominant eyes of 32 strabismic and in both eyes of 35 control children from 4.5 to 10 years, together with a careful orthoptic examination.


RESULTS
In the amblyopic eyes, increased uncertainty and systematic distortions outside the normal range occurred. Large angles of deviation and pathological fixation patterns were necessary, but not sufficient conditions for gross spatial deficits to occur. The fellow dominant eyes showed spatial localization similar to normal eyes.


CONCLUSIONS
Children with strabismic amblyopia exhibited localization deficits and relationship to clinical data similar to those in adult amblyopes. These data are important for further investigations about the substrate, plasticity and the clinical relevance of perceptual distortions.
Fronius
Maria
M
Max Planck Institute for Brain Research, Frankfurt/Main, Germany. fronius@em.uni-frankfurt.de
Sireteanu
Ruxandra
R
Zubcov
Alina
A
D000550:Amblyopia / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D023882:Dominance, Ocular; D006801:Humans; D010468:Perceptual Disorders / Q000175:diagnosis*; D010469:Perceptual Distortion; D013028:Space Perception; D013285:Strabismus / Q000175:diagnosis*; D014787:Vision Tests / Q000379:methods; D015348:Vision, Binocular; D014792:Visual Acuity