Results of Monocular Surgery Under Peribulbar Anesthesia for Large-Angle Horizontal Strabismus

OBJECTIVE To evaluate the results of monocular surgery under peribulbar anesthesia for large-angle horizontal strabismus. INTRODUCTION Monocular surgery may preserve some muscles if a repeat operation is required, may help to avoid the exposure of the dominant eye to the inherent risks of a surgical procedure and may reduce surgical time. METHODS We evaluated ninety-two consecutive patients who underwent monocular surgery under peribulbar anesthesia for large-angle horizontal strabismus (angle of 40 prism diopters or greater). Patients were divided into group 1- esotropia and group 2 -exotropia. The postoperative follow-up was at 6 months, when the residual deviation was evaluated. In cases of residual deviations of over 15 PD (prism diopter), a second procedure was indicated. RESULTS In all patients with preoperative deviations up to 60 PD, residual deviations were under 15 PD. Some patients with preoperative deviations of 65 PD (two in group 1 and four in group 2) and all patients with deviations over 65 PD had residual deviations over 15 PD. The 13 patients who underwent a second procedure experienced successful outcomes. Our ROC curve analysis showed that the cutoff point for obtaining a successful surgical result was 62.5 PD. No patient presented with a major limitation in respect of ocular movement. CONCLUSIONS Monocular surgery under peribulbar anesthesia can be an alternative for horizontal large-angle strabismus given deviations of up to 60 PD. Monocular surgery did not result in successful outcomes for deviations of over 65 PD.