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Sampling and measurement methods for a study of childhood refractive error in a UK population
  1. L O'Donoghue1,
  2. K J Saunders2,
  3. J F McClelland2,
  4. N S Logan3,
  5. A R Rudnicka4,
  6. B Gilmartin5,
  7. C G Owen6
  1. 1School of Biomedical Sciences, University of Ulster, Coleraine, UK
  2. 2University of Ulster, Coleraine, UK
  3. 3Aston University, Ophthalmic Research Group, Birmingham, UK
  4. 4St George's, University of London, London, UK
  5. 5Aston University, Ophthalmic Research Group, Birmingham, UK
  6. 6St George's, University of London, London, UK
  1. Correspondence to Lisa O'Donoghue, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine BT52 1SA, UK; l.odonoghue{at}


Background There is a paucity of data describing the prevalence of childhood refractive error in the United Kingdom. The Northern Ireland Childhood Errors of Refraction study, along with its sister study the Aston Eye Study, are the first population-based surveys of children using both random cluster sampling and cycloplegic autorefraction to quantify levels of refractive error in the United Kingdom.

Methods Children aged 6–7 years and 12–13 years were recruited from a stratified random sample of primary and post-primary schools, representative of the population of Northern Ireland as a whole. Measurements included assessment of visual acuity, oculomotor balance, ocular biometry and cycloplegic binocular open-field autorefraction. Questionnaires were used to identify putative risk factors for refractive error.

Results 399 (57%) of 6–7 years and 669 (60%) of 12–13 years participated. School participation rates did not vary statistically significantly with the size of the school, whether the school is urban or rural, or whether it is in a deprived/non-deprived area. The gender balance, ethnicity and type of schooling of participants are reflective of the Northern Ireland population.

Conclusions The study design, sample size and methodology will ensure accurate measures of the prevalence of refractive errors in the target population and will facilitate comparisons with other population-based refractive data.

  • Myopia
  • refractive error
  • epidemiology
  • methods

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  • Linked article 176040

  • Funding College of Optometrists, London, UK; Northern Ireland Optometric Society, Dromore, Co. Down,UK

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the University of Ulster Research Ethics Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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