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

Objective: To evaluate two cases of intermittent exotropia (IX(T)) treated by vision therapy the efficacy of the treatment by complementing the clinical examination with a 3-D video-oculography 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 IX(T) of 25 prism diopters (Δ) at far and 18 Δ at near and a child of 10 years with 8 Δ of IX(T) in primary position associated to 6 Δ 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 3-D VOG examination (Sensoro Motoric Instruments, Teltow, Germany) 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 IX(T), providing a detailed analysis of vertical and torsional improvements.

Análisis de la eficacia de la terapia visual en el tratamiento de la exotropía intermitente mediante videooculografía 3D

Objetivo: Evaluar la eficacia del tratamiento en 3 casos de exotropia intermitente (XT(i)) mediante ejercicios de terapia visual, completando la exploración clínica con Videooculografia-30 y evidenciar la potencial aplicabilidad de esta tecnología para dicho propósito. Métodos: Exponemos los cambios ocurridos tras ejercicios de terapia visual en una mujer de 36 años con XT(i) de -25 dioptrías prismáticas (dp) de lejos y 18 dp de cerca; Un niño de 10 años de edad con 8 dp de XT(i) en posición primaria, asociados a +6 dp de hipotropia izquierda; y un hombre de 63 años con XT(i) de 6 dp en posición primaria asociada a +7 dp de hipertropia derecha. Todos los pacientes presentaron buena agudeza visual corregida en ambos ojos. La inestabilidad de la desviación ocular se evidenció mediante análisis de VOG-30, revelando la presencia de components verticales y torsionales. Se realizaron ejercicios de terapia visual, incluyendo diferentes tipos de ejercicios de vergencias, acomodación y percepción de la diplopía. Resultados: Tras la terapia visual se obtuvieron excelentes rangos de vergencias fusionales y de punto próximo de convergencia («hasta la nariz»). El examen mediante VOG-3D (Sensoro Motoric lnstruments, Teltow, Germany) confirmó la compensación de la desviación con estabilidad del alineamiento ocular. Se observó una significativa mejora después de la terapia en los components verticals y torsionales, lo cuales se hicieron más estables. Los pacientes se mostraron muy satisfechos de los resultados obtenidos. Conclusión: La VOG-3D es una técnica útil para dotamos de un método objetivo de registro de la compensación y estabilidad de la desviación ocular después de realizar ejercicios de terapia visual en casos de XT(i), ofreciéndonos un detallado análisis de la mejoría de los components verticales y torsionales.

Fixation pattern analysis with microperimetry in nystagmus patients

Objective: To assess the usefulness of microperimetry (MP) as an additional objective method for characterizing the fixation pattern in nystagmus. Design: Prospective study. Participants: Fifteen eyes of 8 subjects (age, 12–80 years) with nystagmus from the Lluís Alcanyís Foundation (University of Valencia, Spain) were included. Methods: All patients had a comprehensive ophthalmologic examination including a microperimetric examination (MAIA, CenterVue, Padova, Italy). The following microperimetric parameters were evaluated: average threshold (AT), macular integrity index (MI), fixating points within a circle of 1° (P1) and 2° of radius (P2), bivariate contour ellipse area (BCEA) considering 63% and 95% of fixating points, and horizontal and vertical axes of that ellipse. Results: In monocular conditions, 6 eyes showed a fixation classified as stable, 6 eyes showed a relatively unstable fixation, and 3 eyes showed an unstable fixation. Statistically significant differences were found between the horizontal and vertical components of movement (p = 0.001), as well as in their ranges (p < 0.001). Intereye comparison showed differences between eyes in some subjects, but only statistically significant differences were found in the fixation coordinates X and Y (p < 0.001). No significant intereye differences were found between microperimetric parameters. Between monocular and binocular conditions, statistically significant differences in the X and Y coordinates were found in all eyes (p < 0.02) except one. No significant differences were found between MP parameters for monocular or binocular conditions. Strong correlations of corrected distance visual acuity (CDVA) with AT (r = 0.812, p = 0.014), MI (r = –0.812, p = 0.014), P1 (r = 0.729, p = 0.002), horizontal diameter of BCEA (r = –0.700, p = 0.004), and X range (r = –0.722, p = 0.005) were found. Conclusions: MP seems to be a useful technology for the characterization of the fixation pattern in nystagmus, which seems to be related to the level of visual acuity achieved by the patient.