In Europe, early surgery for infantile esotropia is defined as surgery before 2 years of age for a strabismus of onset before 4 months. Subject to great controversy, the principal argument concerns binocularity, for some authors attainable with early surgery, for others an unreachable goal. In 2003, the European multicentric "Early versus Late Infantile Strabismus Surgery Study" compared the results of 2 groups of patients at 6 years of age, one having undergone early surgery, between the 6 (th) and the 24 (th) month of life (n = 231), the other later, between the 32 (nd) and the 60 (th) month of life (n = 301). Although slightly better in the early surgery group, the level of binocular functions in the vast majority of cases does not exceed that of subnormal or anomalous binocularity, while to achieve an equivalent postoperative angle the number of operations required was greater with early surgery. Aside from the above-mentioned study, cases of normal binocular single vision have long been reported after early surgery on both sides of the Atlantic. In North America it is sometimes believed that the earlier the surgery, the better the binocularity, some authors advising very early surgery, before 6 months of age. However, such reasoning is open to controversy since extremely early intervention increases the risk of including cases where the diagnosis is not fully established, in particular certain intermittent forms of strabismus that would explain some of the excellent binocular results. The virtue of being preventive rather than curative does not, however, offset the non-negligible fact that very early surgery does increase the risk of a greater number of operations. Indeed, very early surgery raises more questions than it answers, and the best age at surgery remains a subject open to debate.