title: Factors associated with second eye cataract surgery.
abstract: OBJECTIVE
  To analyse the clinical and sociodemographic characteristics associated with second eye cataract surgery.
  
  
  METHODS
  An observational, longitudinal study of patients scheduled for first eye cataract surgery that did not involve a combined procedure was carried at two teaching hospitals and one non-teaching hospital in Barcelona, Spain. Patients were followed for 2 years after first eye cataract surgery to assess whether and when they had undergone second eye cataract surgery. Clinical characteristics, perceived health characteristics (perceived visual function and overall health status), and sociodemographic characteristics were compared between two patient groups-those with surgery in only one eye and those who had undergone surgery in both eyes by the end of the 2 year follow up period.
  
  
  RESULTS
  Of the 242 patients studied, 125 (51.7%) underwent second eye surgery during the 2 year observation period. Patients with visual acuity 6/18 (0.3) or worse in the second eye compared with those with visual acuity over 6/12 (0.5) and patients younger than 65 years compared with patients aged 65-74 were more likely to undergo second eye surgery (adjusted odds ratio 3.9 and 1. 8, respectively). 52 (44.5%) patients in the only one eye surgery group had a visual acuity less than 6/18 (0.3) in the second eye.
  
  
  CONCLUSIONS
  Worse visual acuity in the second eye and younger ages are strongly associated with both eyes cataract surgery. There may be a potential increase of demand for this procedure in the near future since almost half of the patients with only one eye surgery presented a low visual acuity in the second eye.
authors.affiliation: Health Services Research Unit, Institut Municipal d'Investigació Mèdica, Barcelona, Spain.
authors.forename: X
authors.initials: X
authors.lastname: Castells
authors.forename: J
authors.initials: J
authors.lastname: Alonso
authors.forename: C
authors.initials: C
authors.lastname: Ribó
authors.forename: D
authors.initials: D
authors.lastname: Nara
authors.forename: A
authors.initials: A
authors.lastname: Teixidó
authors.forename: M
authors.initials: M
authors.lastname: Castilla
mesh_terms: D000368:Aged; D002386:Cataract / Q000503:physiopathology*; D002387:Cataract Extraction / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D018579:Patient Selection; D018709:Statistics, Nonparametric; D014792:Visual Acuity