title: Correction of visual impairment by cataract surgery and improved survival in older persons: the Blue Mountains Eye Study cohort.
abstract: OBJECTIVE
  We assessed whether correction of visual impairment (VI) by cataract surgery was associated with improved long-term survival in an older Australian population.
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  In the Blue Mountains Eye Study, 354 participants, aged ≥ 49 years, had both cataract and VI or had undergone cataract surgery before baseline examinations. They were subsequently examined after 5- and 10-year follow-ups.
  
  
  METHODS
  Associations between the mortality risk and the surgical correction of VI (visual acuity [VA] <20/40, attributable to cataract) were assessed in Cox proportional hazard regression models, after multivariate adjustment, using time-dependent variables for the study factor.
  
  
  METHODS
  All-cause mortality.
  
  
  RESULTS
  The 15-year crude mortality of participants who had undergone cataract surgery at baseline with no subsequent VI (71.8%) was relatively similar to that in participants with cataract-related VI who had not yet undergone surgery (79.4%). However, after adjusting for age and sex, participants who underwent cataract surgery before baseline or during follow-up and no longer had VI had significantly lower long-term mortality risk (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.46-0.77) than participants with VI due to cataract who had not undergone cataract surgery. This lower mortality risk in the group with surgically corrected VI (HR, 0.54; 95% CI, 0.41-0.73) persisted after further adjustment for smoking, body mass index, home ownership, qualifications, poor self-rated health, the presence of poor mobility, hypertension, diabetes, self-reported history of angina, myocardial infarction, stroke, cancer, asthma, and arthritis. This finding remained significant (HR, 0.55; 95% CI, 0.41-0.73) after additional adjustment for the number of medications taken (continuous variable) and the number (≥ 5 vs. <5) of comorbid conditions (poor mobility, hypertension, diabetes, angina, myocardial infarction, stroke, cancer, asthma, or arthritis) as indicators of frailty.
  
  
  CONCLUSIONS
  Surgical correction of VI due to cataract was associated with significantly better long-term survival of older persons after accounting for known cataract and mortality risk factors, and indicators of general health. Whether some uncontrolled factors (frailty or general health) could have influenced decisions not to perform cataract surgery in some participants is unknown. However, this finding strongly supports many previous reports linking VI with poor survival.
  
  
  BACKGROUND
  Proprietary or commercial disclosure may be found after the references.
authors.affiliation: Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, Sydney, Australia.
authors.forename: Calvin Sze-un
authors.initials: CS
authors.lastname: Fong
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
authors.forename: Elena
authors.initials: E
authors.lastname: Rochtchina
authors.forename: Erdahl T
authors.initials: ET
authors.lastname: Teber
authors.forename: Thomas
authors.initials: T
authors.lastname: Hong
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000150:complications; D002387:Cataract Extraction; D002423:Cause of Death; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009517:New South Wales / Q000453:epidemiology; D016016:Proportional Hazards Models; D015996:Survival Rate; D014786:Vision Disorders / Q000209:etiology / Q000401:mortality* / Q000534:rehabilitation*; D014792:Visual Acuity / Q000502:physiology; D019987:Persons with Visual Disabilities / Q000534:rehabilitation*