Anisometropia in children: Current understanding and clinical implications

Abstract: Anisometropia in children, defined as an interocular refractive difference of at least 1.0 diopter, is a major risk factor for unilateral amblyopia and a significant disruptor of binocular vision. The underlying structural cause is typically asymmetric axial growth, reflecting a breakdown in the normally coordinated process of emmetropization. This narrative review summarizes current evidence on its epidemiology, pathophysiology, associated factors, and management. The condition follows a dynamic age-related pattern: it is prevalent in infancy, declines during early childhood as emmetropization progresses, and rises again during school years and adolescence in parallel with increasing rates of myopia. Genetic predisposition, altered visual feedback, and environmental exposures have been implicated. Reported associated factors include high baseline refractive error, short working distance during near tasks, ocular dominance, and unilateral conditions such as congenital nasolacrimal duct obstruction. Hyperopic anisometropia is particularly amblyogenic because of its early onset and persistent blur. Management centers on prompt optical correction above amblyogenic thresholds to balance visual input, combined with amblyopia therapy when required. In myopic anisometropia, evidence-based myopia-control strategies, such as topical atropine, orthokeratology, and specialized spectacle designs, play an important role in slowing progression and reducing interocular differences. Pediatric anisometropia is both a clinical challenge and a valuable model for studying refractive development. Future longitudinal studies are needed to clarify mechanisms and optimize preventive and therapeutic strategies.