Abstract
Abstract: :
Purpose: Both psychophysical and anatomical studies have shown that strabismus resulting in amblyopia affects the normal development of fibers within the posterior corpus callosum. The purpose of the present study was to determine how strabismus may affect the transfer of information between the two cerebral hemispheres across the corpus callosum in human subjects. Methods: Seven strabismic amblyopes and 10 control subjects were tested using two different procedures. The first involved using two alternative forced choices about the relative size, width, and position of simple visual targets presented either within or between the two visual half-fields. The second involved using simple reaction times to visual stimuli to calculate cross-callosal transmission times. Results: Frequency of seeing curves plotted for the data from the forced choice procedures demonstrated that the Just Noticeable Differences in the strabismic group were significantly greater only when the judgements required cross-callosal transmission of information. In the normal control group there were no differences between the two conditions. The data from the reaction time procedure also indicated longer overall cross-callosal transmission times for the strabismic subjects. In addition, targets presented to the amblyopic eye showed slower over all response times. Conclusions: Strabismus with amblyopia may result in slowed or abnormal cross-callosal transmission of visual information. This finding supports numerous anatomical and electrophysiological studies on strabismus and the resulting abnormal development of the posterior corpus callosum in early life.
Keywords: amblyopia • strabismus • strabismus: diagnosis and detection