title: Prevelence and causes of visual impairment and blindness in older adults in an area of India with a high cataract surgical rate.
abstract: BACKGROUND
  The cataract surgical rate (CSR) in Gujarat, India is reported to be above 10,000 per million population. This study was conducted to investigate the prevalence and causes of vision impairment/blindness among older adults in a high CSR area.
  
  
  METHODS
  Geographically defined cluster sampling was used in randomly selecting persons >or= 50 years of age in Navsari district. Subjects in 35 study clusters were enumerated and invited for measurement of presenting and best-corrected visual acuity and an ocular examination. The principal cause was identified for eyes with presenting visual acuity < 20/32.
  
  
  RESULTS
  A total of 5158 eligible persons were enumerated and 4738 (91.9%) examined. Prevalence of presenting visual impairment < 20/63 to 20/200 in the better eye was 29.3% (95% confidence interval [CI]: 27.5-31.2) and 13.5% (95% CI: 12.0-14.9) with best correction. The prevalence of presenting bilateral blindness (< 20/200) was 6.9% (95% CI: 5.7-8.1), and 3.1% (95% CI: 2.5-3.7) with best correction. Presenting and best-corrected blindness were both associated with older age and illiteracy; gender and rural/urban residence were not significant. Cataract in one or both eyes was the main cause of bilateral blindness (82.6%), followed by retinal disorders (8.9%). Cataract (50.3%) and refractive error (35.4%) were the main causes in eyes with vision acuity < 20/63 to 20/200, and refractive error (86.6%) in eyes with acuity < 20/32 to 20/63.
  
  
  CONCLUSIONS
  Visual impairment and blindness is a significant problem among the elderly in Gujarat. Despite a reportedly high CSR, cataract remains the predominant cause of blindness.
authors.affiliation: International Centre for Eye Health, London School of Hygiene & Tropical Medicine, London. GVS.Murthy@ishtm.ac.uk
authors.forename: Gudlavalleti V S
authors.initials: GV
authors.lastname: Murthy
authors.forename: Praveen
authors.initials: P
authors.lastname: Vashist
authors.forename: Neena
authors.initials: N
authors.lastname: John
authors.forename: Gopal
authors.initials: G
authors.lastname: Pokharel
authors.forename: Leon B
authors.initials: LB
authors.lastname: Ellwein
mesh_terms: D000368:Aged; D001766:Blindness / Q000453:epidemiology* / Q000209:etiology; D002386:Cataract / Q000150:complications / Q000453:epidemiology*; D002387:Cataract Extraction / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012030:Refractive Errors / Q000150:complications / Q000453:epidemiology; D012164:Retinal Diseases / Q000150:complications / Q000453:epidemiology; D015354:Vision, Low / Q000453:epidemiology* / Q000209:etiology; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*