Convergence-accommodation relationships. Description of a simple clinical test and its application to the evaluation of isoflurophate (DFP) therapy.

Introduction The purpose of this study is first to describe a simple test for studying the relationship between the stimulus to accommodation and the accommodative convergence at a fixed near distance, and second to illustrate by case reports the value of graphic analyses of this relationship in classifying oculomotor anomalies and in evaluating various forms of therapy. Previous Investigations The ophthalmological literature of 50 or more years ago includes papers describing the use of graphs to depict relationships between convergence and accommodation and amplitudes of relative fusional convergence and divergence. This early work has been reviewed by Morgan. 1 In recent years two simpler procedures have been used, particularly in research laboratories of physiological optics, to study the changes in convergence induced by changes in accommodation. In most cases only normal subjects without ocular symptoms have been studied. The two procedures may be designated as the variable-distance method and the