title: Prevalence of cataract surgery and postoperative visual outcome in Greater Beijing: the Beijing Eye Study.
abstract: OBJECTIVE
  To determine the prevalence of cataract surgery and the postoperative visual outcome in the adult Chinese population living in rural and urban regions of Greater Beijing.
  
  
  METHODS
  Population-based study.
  
  
  METHODS
  The Beijing Eye Study 2006 included 3251 subjects (73.3%) (aged 45+ years) of 4439 subjects who participated in the 2001 survey and returned for reexamination.
  
  
  METHODS
  The prevalence of surgical pseudophakia/aphakia was assessed, and postoperative visual acuity and reasons for decreased postoperative vision were examined. Visual impairment was defined by a presenting visual acuity (PVA) <6/18 or a best-corrected visual acuity (BCVA) <6/18.
  
  
  METHODS
  Prevalence of cataract surgery, lens status, and causes of visual impairment.
  
  
  RESULTS
  Of the 3215 (98.9% of 3251) subjects for whom data on the lens status were available, 92 (41 male, 133 eyes) had undergone cataract surgery in 1 or both eyes (prevalence rate, 2.86%; 95% confidence interval [CI], 2.28-3.44). In multivariate analysis, this rate was statistically associated with higher age (P<0.001), presence of angle-closure glaucoma (P = 0.02), and higher level of hemorrhagic retinopathy (P<0.001). The prevalence of postoperative visual impairment was 27/133 (20.3%), as defined by a PVA <6/18, and 14/133 or 10.5%, as defined by a BCVA <6/18. Aphakia (odds ratio [OR], 6.71; P = 0.02) and rural residence (OR, 4.05; P = 0.01) were significantly associated with postoperative visual impairment. The most common causes of postoperative visual impairment were uncorrected refractive error followed by hemorrhagic retinopathy and posterior capsule opacification. By comparing 2001 with 2006, the rate of cataract surgery increased, and the rate of postoperative visual impairment decreased significantly (P = 0.049).
  
  
  CONCLUSIONS
  In the adult population of Greater Beijing, approximately 3% of the population aged 45+ years underwent cataract surgery, the prevalence of which was associated with age, angle-closure glaucoma, and hemorrhagic retinopathy. One of 10 subjects who underwent cataract surgery had a BCVA visual of less than 6/18, and 1 of 5 subjects had a PVA of less than 6/18. Low postoperative visual acuity was associated with rural region, undercorrection of refractive error, and hemorrhagic retinopathy.
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Ya Xing
authors.initials: YX
authors.lastname: Wang
authors.forename: Jost B
authors.initials: JB
authors.lastname: Jonas
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001036:Aphakia, Postcataract / Q000453:epidemiology*; D044466:Asian People / Q000706:statistics & numerical data*; D002387:Cataract Extraction / Q000706:statistics & numerical data*; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D019654:Lens Implantation, Intraocular; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D019591:Pseudophakia / Q000453:epidemiology*; D012424:Rural Population / Q000706:statistics & numerical data*; D014505:Urban Population / Q000706:statistics & numerical data*; D014792:Visual Acuity / Q000502:physiology*; D014794:Visual Fields; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data