Congenital esotropia is the most common form of childhood strabismus. Despite its common occurrence, limited information is available about its early clinical course. Such data are needed to determine the earliest age at which surgery can be safely performed without concern that the esotropia is likely to resolve spontaneously. Although the term congenital esotropia implies that the esotropia is present at birth, in many cases the esotropia actually develops sometime during the first few months of life. It is well recognized that congenital esotropia persisting through 6 months of age rarely if ever resolves spontaneously and therefore requires surgical correction. However, it is not clear how often congenital esotropia occurs and then resolves (at an earlier age such that surgery is not necessary) before surgery is required.