Evidence-based Nomenclature for Classification, Diagnosis, and Management of Infantile Exotropia

Despite extensive research on clinical characteristics, patient management, and surgical outcomes of intermittent exotropia, there remains significant confusion regarding the nomenclature system for infantile exotropia, which develops before 12 months of age. Additionally, there still is a controversy over whether infantile exotropia represents the phenotypic counterpart of infantile esotropia or early-onset intermittent exotropia. In this article, we critically review the previous nomenclature systems and propose some modifications to the current classifications of infantile exotropia. These include three diagnostic categories: primary infantile exotropia, early-onset intermittent exotropia, and secondary infantile exotropia. Stereopsis is valuable for differentiation between primary infantile exotropia and early-onset intermittent exotropia. However, further research is needed for more precise descriptions of their clinical features, optimal surgical timing, and proper management.