Evaluation Of The Reflex Fusion Test As A Means Of Screening Binocular Vergence Disorders.

The time required to complete a step vergence eye movement was investigated. The stimulus for the vergence response was binocular retinal image disparity created by horizontal prism. The reflex fusion test was used to stimulate divergence and convergence responses. These responses were timed with fixation directed at both distance and near. Specifically, the stimuli were 6^ BI at distance, lO^ BO at distance, lO^ BI at near, and 15^ BO at near, each installment being performed once. It was suspected that those subjects who failed to complete the vergence eye movement or who required more time to complete the vergence movement would also show latent binocular misalignments such as those classified as Duane-White Syndromes. It was discovered that all subjects who failed to complete a vergence eye movement had binocular motor system disorders. Subjects who were able to complete each step vergence task, but required greater than 3.0s on two or more of the four tasks also were found to have binocular motor disorder. When heterophoria existed, it took longer to complete step vergence movements in the direction which opposed the phoria seventy percent of the time. The effectiveness of this sequence of reflex fusion
tests as a screening method was surveyed.