Infantile onset esotropia is a non-accomodative esotropia starting within the first six months of life with adduction overshooting and variable angle, with or without non accommodative convergence excess. Amblyopia may be associated in 35% to 48% of cases. It may be associated with manifest or latent nystagmus. For the majority of strabismus encountered in children; it has been recommended that, the strabismus can be corrected by simple bilateral ocular muscle surgery, however in infantile onset esotropia, it has been noted that, this approach might not be satisfactory because of the angle variability and the challenging non accommodative convergence excess which might occur in those cases. So in most of cases with infantile onset esotropia a supplementary horizontal surgery is common after the first operation.