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Amblyopia treatment outcomes after preschool screening v school entry screening: observational data from a prospective cohort study
  1. C Williams1,2,
  2. K Northstone1,
  3. R A Harrad2,
  4. J M Sparrow2,
  5. I Harvey3,
  6. and the ALSPAC Study Team*
  1. 1Division of Child Health, University of Bristol, Bristol, UK
  2. 2Bristol Eye Hospital, Lower Maudlin Street, Bristol BS1 2LX, UK
  3. 3School of Medicine, Health Policy and Practice, University of East Anglia, Norwich NR4 7TJ, UK
  1. Correspondence to: Miss C Williams, Division of Child Health, ALSPAC Study, 24 Tyndall Avenue, Bristol BS8 1TQ, UK; Cathy.Williams{at}


Background/aims: Preschool screening for amblyopia has controversially been abandoned in some localities within the United Kingdom, on the basis that there is no clear evidence of benefit to support its continuation. Data collected within a birth cohort study were used to examine visual outcomes at 7½ years in children who did or did not receive preschool vision screening.

Methods: Monocular logMAR visual acuity with and without a pinhole was assessed by orthoptists. Contemporary records were used to identify children who had been offered and/or received preschool screening.

Results: Of 6081 children, 24.9% had been offered preschool screening and 16.7% had attended. The prevalence of amblyopia was approximately 45% lower in the children who received preschool screening than in those who did not (1.1% v 2.0%, p = 0.05). The mean acuity in the worse seeing eyes after patching treatment was better for amblyopic children who received preschool screening than for those who did not; 0.14 v 0.20 logMAR (p <0.001). These effects did not persist in an intention to screen analysis.

Conclusions: Preschool screening at 37 months was associated with an improved treatment outcome for individuals with amblyopia. However, the improvement was clinically small and disappeared when considering all children offered screening rather than only those who received it. Further research is needed into improving the effectiveness of vision screening for preschool children, while in the interim these data do not conflict with current recommendations for school entry screening by orthoptists.

  • prospective cohort study
  • amblyopia
  • screening

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  • * Members of the team are listed in the acknowledgements.

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