Disparity-induced vergence joined with saccadic eye movements: Possible use in the rehabilitation of intermittent exotropia

Disparity-induced vergence was studied in combination with saccadic eye movements. The increase in vergence speed obtained in these cases is known. The variations of the saccadic and postsaccadic eye movements among different tests were studied to estimate the normal subject's capability to pre-program both version and vergence in order to reach a sensorial fusion of the target as fast as possible. Training with a repetitive stimulus decreased the time necessary to realize the disjunctive movement and the latency of convergence. The presence of short and long alternated disjunctive movements since the beginning of the test support the idea that a pre-programming of the vergence component is immediately possible, even if repeated stimulations are not used. Consequently, cases of intermittent exotropia could be treated by means of an optical exercise able to increase the patient's ability to pre-program, in all dynamic visual conditions, the vergence component with the saccade. In this way, the decompensation of latent strabismus can be made faster.