title: Cost-effectiveness of screening and correcting refractive errors in school children in Africa, Asia, America and Europe.
abstract: OBJECTIVE
  To estimate the costs and effects of alternative strategies for annual screening of school children for refractive errors, and the provision of spectacles, in different WHO sub-regions in Africa, Asia, America and Europe.
  
  
  METHODS
  We developed a mathematical simulation model for uncorrected refractive error, using prevailing prevalence and incidence rates. Remission rates reflected the absence or presence of screening strategies for school children. All screening strategies were implemented for a period of 10 years and were compared to a situation were no screening was implemented. Outcome measures were life years adjusted for disability (DALYs), costs of screening and provision of spectacles and follow-up for six different screening strategies, and cost-effectiveness in international dollars per DALY averted. Epidemiological information was derived from the burden of disease study from the World Health Organization (WHO). Cost data were derived from large databases from the WHO. Both univariate and multivariate sensitivity analyses were performed on key parameters to determine the robustness of the model results.
  
  
  RESULTS
  In all regions, screening of 5-15 years old children yields most health effects, followed by screening of 11-15 years old, 5-10 years old, and screening of 8 and 13 years old. Screening of broad-age intervals is always more costly than screening of single-age intervals, and there are important economies of scale for simultaneous screening of both 5-10 and 11-15-year-old children. In all regions, screening of 11-15 years old is the most cost-effective intervention, with the cost per DALY averted ranging from I$67 per DALY averted in the Asian sub-region to I$458 per DALY averted in the European sub-region. The incremental cost per DALY averted of screening 5-15 years old ranges between I$111 in the Asian sub-region to I$672 in the European sub-region.
  
  
  CONCLUSIONS
  Considering the conservative study assumptions and the robustness of study conclusions towards changes in these assumptions, screening of school children for refractive error is economically attractive in all regions in the world.
authors.affiliation: International Health Unit, Department of Public Health, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands. r.baltussen@sg.umcn.nl
authors.forename: Rob
authors.initials: R
authors.lastname: Baltussen
authors.forename: Jeroen
authors.initials: J
authors.lastname: Naus
authors.forename: Hans
authors.initials: H
authors.lastname: Limburg
mesh_terms: D000293:Adolescent; D000349:Africa / Q000453:epidemiology; D001208:Asia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003362:Cost-Benefit Analysis; D005060:Europe / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008403:Mass Screening / Q000191:economics*; D012030:Refractive Errors / Q000175:diagnosis* / Q000453:epidemiology; D012574:Schools; D014481:United States / Q000453:epidemiology