title: "With the rule" astigmatism is not the rule in the elderly. Reykjavik Eye Study: a population based study of refraction and visual acuity in citizens of Reykjavik 50 years and older. Iceland-Japan Co-Working Study Groups.
abstract: OBJECTIVE
  To study refractive state and visual acuity in citizens of Reykjavik 50 years and older.
  
  
  METHODS
  1700 persons were randomly selected from the national population census. 1379 could be located and qualified whereof 1045 participated. Evaluation of refraction was performed using Nidek ARK 900 autorefracto-keratometer. Visual acuity was tested on a Snellen chart.
  
  
  RESULTS
  The prevalence of hypermetropia increases with age by 0.3 D in five years. The prevalence of "against the rule" astigmatism increased on average 5.3% and oblique 3.9% in five years. Analysis of corneal astigmatism measured by keratometer shows an "against the rule" change with age.
  
  
  CONCLUSIONS
  Hypermetropia increases by age. The prevalence of astigmatism increases and the axis turns to "against the rule". The changes in total astigmatism and corneal astigmatism is almost parallel which might indicate that the "against the rule" change is related to changes in the cornea.
authors.affiliation: Department of Ophthalmology, University of Iceland.
authors.forename: E
authors.initials: E
authors.lastname: Gudmundsdottir
authors.forename: F
authors.initials: F
authors.lastname: Jonasson
authors.forename: V
authors.initials: V
authors.lastname: Jonsson
authors.forename: E
authors.initials: E
authors.lastname: Stefánsson
authors.forename: H
authors.initials: H
authors.lastname: Sasaki
authors.forename: K
authors.initials: K
authors.lastname: Sasaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001251:Astigmatism / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology / Q000503:physiopathology; D007055:Iceland / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000453:epidemiology / Q000503:physiopathology; D015995:Prevalence; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology