Abstract
Abstract: :
Purpose:Controversial statements have been published about the dominant eyes of amblyopes: from "impaired function" to even "supernormal function". Testing different visual functions or testing groups of observers not matched in age or in previous training with psychophysical tasks may have contributed to these discrepancies. Our aim was to compare spatial localization and visual acuity in the dominant eyes of children with strabismic amblyopia with a group of age matched control children with normal vision. Methods:Vertical alignment of 3 stimuli separated by 5 deg of visual angle (see Fronius et al., Strabismus 8, 243-249, 2000) and visual acuity (single and crowded Lanolt rings) were tested in the dominant eyes of 32 children with strabismic amblyopia (4,5 to 10 years old) and in 32 age matched children with normal or corrected to normal vision. Both groups were inexperienced in psychophysical testing. To check for the impact of occlusion,19 amblyopic children were followed prospectively during 6 to 12 months of occlusion therapy. Results: Acuity and spatial localization showed improvement over the tested age span in both groups. Spatial localization was not significantly different between the two groups (P>0,05). However, visual acuity was significantly reduced in the dominant eyes of the amblyopes (P<0,01), most markedly in the younger children and in the crowded acuity test. No impact of occlusion treatment on the function of the dominant eyes was observed during 6 months of occlusion. However, after longer occlusion, subtle distortions appeared in the spatial localization of some of the dominant eyes. Conclusions: Both control children and the dominant eyes of amblyopic children showed development of visual acuity and spatial localization. However, while vertical alignment of the dominant eyes was in the normal range, visual acuity was impaired. Development of both functions and reduced acuity in the dominant eyes of amblyopes might be relevant for performance of these children in their every-day life, e.g. for the acquisition of reading skills in elementary school.
Keywords: amblyopia • visual acuity • space perception