Prevalence of the different types of age-related cataract in an African population

N. Congdon, Sheila K West, R. R. Buhrmann, A. Kouzis, Beatriz Munoz, H. Mkocha

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PURPOSE. To describe the prevalence of different types of cataract and their association with visual acuity in a Tanzanian population aged 40 years and older. METHODS. A prevalence survey for lens opacity, glaucoma, and visual impairment was carried out on all residents age 40 and older of six villages in Kongwa, Tanzania. One examiner graded the lens for presence of nuclear (NSC), posterior subcapsular (PSC), and cortical cataract (CC), using the new WHO Simplified Cataract Grading System. Visual acuity was measured in each eye, both presenting and best corrected, using an illiterate E chart. RESULTS. The proportion of eligible subjects participating was 90% (3268/3641). The prevalence of cataract was as follows: NSC, 15.6%; CC, 8.8%; and PSC, 1.9%. All types of cataract increased with age, from NSC, 1.7%; CC, 2.4%; and PSC, 0.4% for those aged 40 to 49 years to NSC, 59.2%; CC, 23.5%; and PSC, 5.9% for those aged 70 years and older (P2 test for trend). Cataract prevalence was higher among women than men for NSC (P=0.0001), but not for CC (P=0.15) or PSC (P=0.25), after adjusting for age. Prevalence rates of visual impairment (BCVA

Original languageEnglish (US)
Pages (from-to)2478-2482
Number of pages5
JournalInvestigative Ophthalmology and Visual Science
Issue number11
Publication statusPublished - 2001
Externally publishedYes


ASJC Scopus subject areas

  • Ophthalmology

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