title: [Epidemiologic study of refractive errors in schoolchildren in socioeconomically deprived regions in Tunisia].
abstract: OBJECTIVE
  This study's purpose was to estimate the prevalence of common refractive errors in schoolchildren in low socioeconomic regions in Tunisia and to assess their effect on school performance.
  
  
  METHODS
  This was a cross-sectional study done from November 1999 to January 2000 within the context of health care screening campaigns carried out by volunteer ophthalmologists and opticians in low-end socioeconomic regions in Tunisia. The concerned population was schoolchildren living in the cities of Tunis and Tabarka (North), Kerkena (Center), and Tozeur (South). We examined a total of 708 children with a mean age of 11.9 +/-3.21 years (from 6 to 20 years) and a sex ratio of 0.84. A cycloplegic refraction examination was performed on all the children. Statistical analyses with the chi squared test and the Fisher exact test allowed us to calculate the prevalence of the refractive errors totally and separately as well as the distribution according to age, sex, and region. We also searched for a possible relation between refractive errors and academic failure.
  
  
  RESULTS
  Among the 708 children, 57.2% [CI(95)=53.4-60] had refractive errors, of which 31.6% [CI(95)=28.2-35.2] were hyperopic, whereas 9.1% [CI(95)=7.1-11.5] were myopic. Astigmatism was found in 16.4% [CI(95)=13.7-19.3]. The prevalence of myopia was significantly higher after the age of fourteen. It increased significantly with age (P=0.0003). The prevalence of hyperopia was significantly higher between the ages of 8 and 11 (P=0.0004). Hyperopic astigmatism was significantly more frequent between 6 and 9 years of age (P=0.001). There was no significant difference regarding sex. However, the distribution of the refractive errors by region showed a significantly high level of myopia in Tunis, Kerkena, and Tozeur. This difference disappeared with increasing age. The study of the effect of these refractive errors on school performance of these children from poor areas showed a significant association between all types of refractive errors and academic failure, with an odds ratio of 2.13 for all types of refractive errors, 2.69 for hyperopia, 2.87 for myopia, and 2.73 for astigmatism.
  
  
  CONCLUSIONS
  This study showed the prevalence of refractive errors in a poor population of schoolchildren and emphasized the importance of such examinations. The ability of a child to participate in the educational experience is at least partially dependent on good vision.
authors.affiliation: Institut Hédi Rais d'ophtalmologie de Tunis, Service B, France.
authors.forename: T
authors.initials: T
authors.lastname: Ayed
authors.forename: M
authors.initials: M
authors.lastname: Sokkah
authors.forename: O
authors.initials: O
authors.lastname: Charfi
authors.forename: L
authors.initials: L
authors.lastname: El Matri
mesh_terms: D000293:Adolescent; D001251:Astigmatism / Q000453:epidemiology; D002648:Child; D006801:Humans; D008403:Mass Screening / Q000706:statistics & numerical data; D009216:Myopia / Q000453:epidemiology; D011203:Poverty; D015995:Prevalence; D012030:Refractive Errors / Q000453:epidemiology*; D014416:Tunisia / Q000453:epidemiology