title: Population-based study of presbyopia in rural Tanzania.
abstract: OBJECTIVE
  To determine the prevalence of presbyopia in a rural African population.
  
  
  METHODS
  Cross-sectional prevalence study.
  
  
  METHODS
  One thousand seven hundred nine persons age 40 years and older who resided in 3 villages and randomly selected neighborhoods of Kongwa town, Tanzania.
  
  
  METHODS
  Eligible persons were refracted and given best distance correction. Near vision was tested and corrected to the nearest 0.5 diopter. Presbyopia was defined as at least 1 line of improvement on a near visual acuity chart with an addition of a plus lens.
  
  
  RESULTS
  A total of 61.7% of eligible participants were presbyopic. A higher prevalence of presbyopia was associated with increased age, female gender, higher educational level, and residence in town (odds ratio = 3.09; 95% confidence interval: 2.46-3.90). The odds of developing presbyopia increased 16% per year of age from age 40 to 50, but the increase was nonsignificant at 1% per year after age 50. More severe presbyopia was associated with female gender and less with education.
  
  
  CONCLUSIONS
  This study provides the first population-based data on prevalence of presbyopia in a large, random sample of older Africans and suggests a high rate of presbyopia. Presbyopia plateaus after age 50, and it is more common in females. In addition, the 3-fold increased odds in town versus village dwellers was unexpected and suggests that research of other factors, including environmental factors, is warranted.
authors.affiliation: Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Burke
authors.forename: Ilesh
authors.initials: I
authors.lastname: Patel
authors.forename: Beatriz
authors.initials: B
authors.lastname: Munoz
authors.forename: Andrew
authors.initials: A
authors.lastname: Kayongoya
authors.forename: Wilson
authors.initials: W
authors.lastname: McHiwa
authors.forename: Alison W
authors.initials: AW
authors.lastname: Schwarzwalder
authors.forename: Sheila K
authors.initials: SK
authors.lastname: West
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D003430:Cross-Sectional Studies; D004522:Educational Status; D005139:Eyeglasses / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011159:Population Surveillance; D011305:Presbyopia / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D015995:Prevalence; D012029:Refraction, Ocular; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data*; D012737:Sex Factors; D013636:Tanzania / Q000453:epidemiology; D015351:Vision Screening; D014792:Visual Acuity