Evaluation of Binocular Vision Therapy Efficacy by 3D Video-Oculography Measurement of Binocular Alignment and Motility.

Objective: To evaluate two cases of intermittent exotropia treated by vision therapy the efficacy of the treatment by complementing the clinical examination with a 3D videooculography to register and to evidence the potential applicability of this technology for such purpose.

Methods: We report the binocular alignment changes occurring after vision therapy in a woman of 36 years with an intermittent exotropia of 25 prism diopters at far and 18 PD at near and a child of 10 years with 8 PD of intermittent exotropia in primary position associated to 6 PD of left eye hypotropia. Both patients presented good visual acuity with correction in both eyes. Instability of ocular deviation was evident by VOG analysis, revealing also the presence of vertical and torsional components. Binocular vision therapy was prescribed and performed including different types of vergence, accommodation, and consciousness of diplopia training.

Results: After therapy, excellent ranges of fusional vergence and a to-the-nose near point of convergence were obtained.The 3D VOG examination confirmed the compensation of the deviation with a high level of stability of binocular alignment. Significant improvement could be observed after therapy in the vertical and torsional components that were found to become more stable. Patients were very satisfied with the outcome obtained by vision therapy.

Conclusion: 3D-VOG is a useful technique for providing an objective register of the compensation of the ocular deviation and the stability of the binocular alignment achieved after vision therapy in cases of intermittent exotropia, providing a detailed analysis of vertical and torsional improvements.