Current clinical practice is to defer surgery for congenital esotropia until 6 to 12 months of age. Assuming that characteristics of congenital esotropia at 2 to 4 months of age can be identified to predict which cases will require surgery, then a trial will be warranted to determine whether performing earlier surgery enhances the development of binocular vision. The potential benefit to very early surgery is supported by neurophysiologic research, which has shown that (1) congenital esotropes may be born with the innate ability to develop binocular vision, (2) there is a critical period for development of normal binocular function within the first few months of life that is dependent on alignment of the visual axes of the two eyes, and (3) ocular misalignment alone, regardless of its mechanism, without a coexisting primary cortical fusion deficit, can account for abnormal development of binocular vision. Clinical reports have demonstrated that surgical correction of the esotropia between 6 and 12 months of age provides for enhanced development of stereoacuity compared with later surgery. However, there are limited data on the outcomes in infants who had surgical correction before age 6 months.