title: Risk of bilateral visual impairment in individuals with amblyopia: the Rotterdam study.
abstract: BACKGROUND
  The excess risk of bilateral visual impairment (BVI; bilateral visual acuity <0.5) among individuals with amblyopia is an argument for screening for amblyopia, but data are scarce.
  
  
  METHODS
  The risk was estimated by determining the incidence of BVI in the Rotterdam Study, a population-based cohort of subjects aged 55 years or over (n = 5220), including 192 individuals with amblyopia (3.7%). Using a multistate lifetable, the lifetime risk and excess period spent with BVI were determined.
  
  
  RESULTS
  The relative risk of BVI for amblyopes was 2.6 (95% confidence interval 1.4-4.5). For individuals with amblyopia, the lifetime risk of BVI was 18%, whereas they lived on average 7.2 years with BVI. For non-amblyopic individuals, these figures were 10% and 6.7 years, respectively.
  
  
  CONCLUSIONS
  Amblyopia nearly doubles the lifetime risk of BVI and affected individuals spent an extra six months with BVI. This study provides data for future cost-effectiveness analyses.
authors.affiliation: Department of Epidemiology and Biostatistics, Erasmus Medical Center, Rotterdam, the Netherlands. r.vanleeuwen@erasmusmc.nl
authors.forename: Redmer
authors.initials: R
authors.lastname: van Leeuwen
authors.forename: Marinus J C
authors.initials: MJ
authors.lastname: Eijkemans
authors.forename: Johannes R
authors.initials: JR
authors.lastname: Vingerling
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.forename: Paulus T V M
authors.initials: PT
authors.lastname: de Jong
authors.forename: Huib J
authors.initials: HJ
authors.lastname: Simonsz
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000550:Amblyopia / Q000150:complications* / Q000503:physiopathology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D013997:Time Factors; D015354:Vision, Low / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D014792:Visual Acuity