Preferred postoperative alignment after congenital esotropia surgery.

A total of 117 patients with congenital esotropia who underwent muscle surgery were included in our study and were followed for a minimum of three years. Only those patients who were orthotropic or were within +/- 10 prism diopters (PD) of orthotropia six months postoperatively were included. Of the 117 patients, 101 patients (86%) remained orthotropic or within +/- 10 PD of orthotropia three years postoperatively, but 13 patients (11%) developed consecutive exotropia (greater than 10 PD). Five years after surgery, 17 of 68 patients (25%) had consecutive exotropia (greater than 10 PD). Our study demonstrates that despite satisfactory postoperative alignment, there is a steady progression towards exotropic drift over long-term follow-up. Our study also suggests that a preferred alignment shortly after congenital esotropia surgery is within 10 PD of esotropia since all of the patients who had consecutive exotropia (greater than 10 PD) were either orthotropic or exotropic (less than or equal to 10 PD) six months after surgery.