Prevalence of glaucoma in a rural east African population

PURPOSE. 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 enumerate d and invited to a comprehensive eye examination including presenting visua l acuity, refraction, automated 40-point Dicon (San Diego, CA) suprathresho ld screening field test, Tone-Pen (Bio-Rad, Inc., Boston, MA) intraocular p ressure (IOP) measurement, and standardized examination by an ophthalmologi st of anterior segment, optic nerve head, and retina after pupil dilation. Gonioscopy and Glaucoma-Scape (Ophthalmic Imaging Systems, Sacramento, CA) optic disc imaging were performed on those with IOP higher than 23 mm Hg an d cup-to-disc ratio (c/d) more than 0.6 and on a 20% random sample of parti cipants. RESULTS. Of 3641 eligible persons, 3268 (90%) underwent ophthalmic examinat ion. The prevalence of glaucoma of all types was 4.16% (95% confidence inte rval [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 criteri a. CONCLUSIONS. The high prevalence of OAG in this group was similar to that o f African-derived persons in the United States but less than in African-Car ibbean populations. ACG was more prevalent in east Africans than suggested by anecdotal reports.