Prevalence of convergence insufficiency among Spanish school children aged 6 to 14 years.

Clinical Relevance: Convergence insufficiency (CI) at an early age can lead to learning difficulties affecting school performance. The aim of this study was to examine the prevalence of CI in a non-clinical population of Spanish children using well defined clinical criteria and to determine whether sex is a risk factor.

Methods: Visual acuity and binocular vision tests were performed in 628 children aged 6-14 years (mean age 9.