title: Prevalence and causes of corneal blindness.
abstract: BACKGROUND
  The study aimed to assess the prevalence and causes of corneal blindness in a rural northern Chinese population.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  The cluster random sampling method was used to select the sample.
  
  
  METHODS
  This population-based study included 11 787 participants of all ages in rural Heilongjiang Province, China. These participants underwent a detailed interview and eye examination that included the measurement of visual acuity, slit-lamp biomicroscopy and direct ophthalmoscopy. An eye was considered to have corneal blindness if the visual acuity was <9/18 because of corneal diseases.
  
  
  METHODS
  The main outcome measure was prevalence rates of corneal blindness and low vision.
  
  
  RESULTS
  Among the 10 384 people enrolled in the study, the prevalence of corneal blindness is 0.3% (95% confidence interval 0.2-0.4%). The leading cause was keratitis in childhood (40.0%), followed by ocular trauma (33.3%) and keratitis in adulthood (20.0%). Age and illiteracy were found to be associated with an increased prevalence of corneal blindness.
  
  
  CONCLUSIONS
  Blindness because of corneal diseases in rural areas of Northern China is a significant public health problem that needs to be given more attention.
authors.affiliation: The First Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Haijing
authors.initials: H
authors.lastname: Wang
authors.forename: Yaoguang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Li
authors.forename: Tiebin
authors.initials: T
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001766:Blindness / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D065306:Corneal Injuries; D003318:Corneal Opacity / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D003430:Cross-Sectional Studies; D004522:Educational Status; D005131:Eye Injuries / Q000150:complications; D005260:Female; D006801:Humans; D007223:Infant; D007634:Keratitis / Q000150:complications; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012424:Rural Population / Q000706:statistics & numerical data; D017678:Sex Distribution; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
keywords: blindness; corneal diseases; population-based; rural area