title: Are children with myopia more intelligent? A literature review.
abstract: OBJECTIVE
  Refractive errors are a serious worldwide problem. So far a few papers have described the relationship between refractive errors and intelligence. However, based on the growing interest into the relationship between refractive errors and intelligence quotient (IQ) we decided to present and discuss the latest results of the clinical studies on that subject.
  
  
  METHODS
  A review of the literature concerning the relationship between refractive errors and IQ was done.
  
  
  RESULTS
  In 1958 Nadell and Hirsch found that children in America with myopia have a higher IQ. A similar relationship has been described by other researchers from the USA, the Czech Republic, Denmark, Israel, New Zealand, and Singapore. In other related studies, it was reported that myopic children regardless of their IQ gain better school achievements--table 1. It was also observed that schoolchildren with hyperopia have a lower IQ and gain worse school achievements--table 2. Several hypotheses explaining the relationship between refractive errors and intelligence have been published. Recently, Saw et al. concluded that higher IQ may be associated with myopia, independent of books read per week, in schoolchildren. According to them "the association between genetically driven IQ and myopia of hereditary predisposition could be forged because of a pleiotropic relationship between IQ and myopia in which the same causal factor is reflected in both genetic traits. There may be similar genes affecting eye size or growth (associated with myopia) and neocortical size (possibly associated with IQ)".
  
  
  CONCLUSIONS
  The conducted clinical observations suggest that children with myopia may have a higher IQ. This relationship is most probably determined by genetic and environmental factors.
authors.affiliation: Katedra i Klinika Okulistyki Pomorskiej Akademii Medycznej w Szczecinie al. Powstańców Wlkp. 72, 70-111 Szczecin.
authors.forename: Damian
authors.initials: D
authors.lastname: Czepita
authors.forename: Ewa
authors.initials: E
authors.lastname: Lodygowska
authors.forename: Maciej
authors.initials: M
authors.lastname: Czepita
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology; D007361:Intelligence Tests / Q000706:statistics & numerical data*; D008297:Male; D009216:Myopia / Q000453:epidemiology*