Amblyopia is a neurodevelopmental disorder that aff ects at least 2% of most populations and can lead to permanently reduced vision if not detected and treated within a specifi c period in childhood. Whole-population screening of children younger than 5 years is applied in many countries. The substantial diversity in existing programmes refl ects their heterogeneous implementation in the absence of the complete evidence base that is now a pre-requisite for instituting screening. The functional importance of amblyopia at an individual level is unclear as data are scarce, but in view of the high prevalence the population-level eff ect might be notable. Screening of all children aged 4–5 years (eg, at school entry) confers most benefi t and addresses inequity in access to timely treatment. Screening at younger ages is associated with increased risk of false-positive results, and at older ages with poor outcomes for children with moderate to severe amblyopia. We suggest that the real-life adverse eff ects of amblyopia should be characterised and screening and diagnosis should be standardised.

Amblyopia is a neurodevelopmental disorder that aff ects at least 2% of most populations and can lead to permanently reduced vision if not detected and treated within a specifi c period in childhood. Whole-population screening of children younger than 5 years is applied in many countries. The subs...