Three groups of subjects were included in this study. Group 1 had typically developing children from five to nine years with heterophoria less than 6PD. Group 2 had 19 children aged five to nine years with intermittent distance exotropia. Group 3 had 17 naïve young adults and children with near exophoria less than 6PD. Near and distance stimulus accommodative convergence to accommodation (AC/A) assessment with gradient prism cover test after 30 minutes of monocular occlusion was undertaken with a lab method of assessment. Results showed a poor or non-existent correlation between near and distance clinical AC/A ratios. Strong and significant associations were found for lab response convergence accommodation to convergence (CA/A) ratio and near clinical stimulus AC/A ratio. This suggests the near AC/A may reflect accommodative response to change in vergence cues following dissociation of prism cover test and disruption of vergence accommodation. 

The clinical near gradient stimulus AC/A ratio correlates better with the response CA/C ratio than with the response AC/A ratio.
Horwood AM, Riddell PM.
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Fiona Rowe (Prof)

Institute of Population Health, University of Liverpool, UK.

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