title: Prevalence of glaucoma in a rural East African population.
abstract: OBJECTIVE
  To determine the prevalence of glaucoma in an adult population in rural central Tanzania.
  
  
  METHODS
  Six villages were randomly selected from eligible villages in the Kongwa district, and all residents more than 40 years of age were enumerated and invited to a comprehensive eye examination including presenting visual acuity, refraction, automated 40-point Dicon (San Diego, CA) suprathreshold screening field test, Tono-Pen (Bio-Rad, Inc., Boston, MA) intraocular pressure (IOP) measurement, and standardized examination by an ophthalmologist of anterior segment, optic nerve head, and retina after pupil dilation. Gonioscopy and Glaucoma-Scope (Ophthalmic Imaging Systems, Sacramento, CA) optic disc imaging were performed on those with IOP higher than 23 mm Hg and cup-to-disc ratio (c/d) more than 0.6 and on a 20% random sample of participants.
  
  
  RESULTS
  Of 3641 eligible persons, 3268 (90%) underwent ophthalmic examination. The prevalence of glaucoma of all types was 4.16% (95% confidence interval [CI] = 3.5, 4.9%). Primary open-angle glaucoma (OAG) was diagnosed in 3.1% (95% CI = 2.5, 3.8%), primary angle-closure glaucoma (ACG) in 0.59% (95% CI = 0.35, 0.91%), and other forms of glaucoma in 0.49%. The prevalence of glaucoma was found to be sensitive to changes in the diagnostic criteria.
  
  
  CONCLUSIONS
  The high prevalence of OAG in this group was similar to that of African-derived persons in the United States but less than in African-Caribbean populations. ACG was more prevalent in east Africans than suggested by anecdotal reports.
authors.affiliation: Dana Center for Preventive Ophthalmology and the Glaucoma Service, Wilmer Ophthalmologic Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Buhrmann
authors.forename: H A
authors.initials: HA
authors.lastname: Quigley
authors.forename: Y
authors.initials: Y
authors.lastname: Barron
authors.forename: S K
authors.initials: SK
authors.lastname: West
authors.forename: M S
authors.initials: MS
authors.lastname: Oliva
authors.forename: B B
authors.initials: BB
authors.lastname: Mmbaga
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis / Q000453:epidemiology*; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000453:epidemiology*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology; D015995:Prevalence; D011897:Random Allocation; D012424:Rural Population / Q000706:statistics & numerical data*; D013636:Tanzania / Q000453:epidemiology; D014794:Visual Fields