Smartphone-Associated Acute Acquired Comitant Esotropia: A Contemporary Review

Abstract The widespread adoption of smartphones has been increasingly linked to the emergence of smartphone-associated acute acquired comitant esotropia (SAACE), especially in adolescents and young adults. This narrative review synthesises current evidence on the epidemiology, pathophysiology, clinical features, diagnostic challenges, and management strategies of SAACE. SAACE is thought to originate from sustained near fixation at reduced viewing distances, which places excessive demand on convergence mechanisms while limiting divergence and accommodation relaxation. Although myopia frequently coexists, SAACE may occur across refractive spectra, underscoring behavioural strain rather than refractive error as the primary aetiology. Patients typically present with sudden-onset diplopia and comitant esodeviation—often more pronounced at distance fixation—yet retain substantial binocular potential due to their mature binocular systems. First-line management emphasises behavioural modification, specifically restricting smartphone use and improving visual hygiene. In mild to moderate cases, prism lenses, cycloplegic drops, and botulinum toxin A injections may further support alignment recovery. Persistent or large-angle deviations often require surgical correction, preferably guided by a prism adaptation test to optimise outcomes. Prognosis is favourable in patients who present early and maintain good stereoacuity, while delayed intervention and excessive screen use correlate with poorer outcomes. Based on current literature, ophthalmologists should maintain vigilance for SAACE in patients with new-onset diplopia and heavy digital device exposure. Further research is needed to define safe screen-use thresholds, long-term visual outcomes, and standardised guidelines for management.