Discriminant analysis of acquired esotropia surgery. Predictor variables for short- and long-term outcomes

In a retrospective study, a computer-based stepwise discriminant analysis was used to create a biostatistical model of the results of surgery in acquired esotropia. One hundred seventy-two patients who had bilateral medial rectus muscle recession as an initial operative procedure with at least 6 months postoperative follow-up were studied. The outcome groups for the discriminant analysis were based on the ocular deviation 6 weeks after the first surgery and at the patient's last visit, or the presence or absence of stereopsis at the last visit. With respect to the two predominant ocular deviation groups (Esotropia or Success) 6 weeks after surgery, 11 independent variables were analyzed; those determined to be prognostic of the outcome grouping were refractive error of the left eye and preoperative deviation, in that order. With respect to ocular deviation at last visit, 146 patients were followed for over 2 years and were last examined when over 5 years of age; of the 12 independent variables analyzed, postoperative deviation at 6 weeks, refractive error of the right eye, and age of onset were predictive. With respect to stereopsis, 126 patients had similar follow-up; of the 11 independent variables analyzed, only postoperative deviation at 6 weeks was prognostic. The results indicate that in patients with acquired esotropia the postoperative deviation is the most important prognostic factor for both the maintenance of ocular alignment and the status of stereopsis; refractive error and the age of onset of the esotropia influence the ocular alignment at the last visit.