Purpose: To evaluate the factors involved in the development of consecutive exotropia (XTc), and the surgical procedures used for its treatment.
Patients and methods: A retrospective study on 30 patients who underwent surgery for XTc was carried out in our Department. The following characteristics were studied prior to surgery: anamnesis, refraction, deviation angle measurement, detection of amblyopia and diplopia prior to the operation, abnormal head posture rotations and presence of any vertical deviation and anisotropy. The surgical technique used was individually considered for each patient and included bilateral lateral rectus recessions and/or unilateral medial rectus advancement to its/their original insertion site.
Results: Before surgery, 53.33% of our patients showed amblyopia, 66.66% of them showed rotation limitation, 46.66% showed dissociated vertical deviation (DVD), 20% had abnormal head posture and 10% diplopia. <<Good>> results (residual deviation of 10 prism diopters or less) were obtained in 70% of our patients. More than half of our cases were corrected with one single procedure.
Conclusions: The presence of amblyopia, rotation limitations and vertical deviations (DVD and/or alphabetical syndromes) were found to be the most common factors in the development of a XTc in our study. The results indicate that a residual angle less than 10 prism diopters is obtained in 70% of our patients. The technique of choice is a bilateral lateral rectus muscle recession for deviations up to 35 prism diopters. The association of an advancement of one or both medial rectus muscles is necessary when the initial deviation exceeds 35 prism diopters.