Glaucoma in Zulus: a population-based cross-sectional survey in a rural district in South Africa

To determine the prevalence and the main types of glaucoma in a representative adult population in rural Zululand, and to describe the distribution of glaucoma-related variables in healthy subjects and those with glaucoma.

A population-based, cross-sectional study.

Hlabisa district, Northern KwaZulu-Natal Province, South Africa.

Resident individuals of Zulu ethnic origin, 40 years or older.

Glaucoma was diagnosed by means of strict objective criteria, based on binocular indirect ophthalmoscopic optic disc appearances validated by results of disc photography and threshold visual field testing.

From an eligible sample of 1115 subjects, 1005 (90.1%) were examined in the survey. The adjusted prevalence of glaucoma of all types was 4.5%, and primary open-angle glaucoma accounted for 2.7%. Secondary glaucoma occurred with an adjusted prevalence of 1.7%, of which the principal contributors were exfoliative and aphakic glaucoma. The prevalence of primary angle-closure glaucoma was low. Normal tension (intraocular pressure, < or =21 mm Hg) was measured in 16 (57.1%) of 28 cases of primary open-angle glaucoma. Age- and sex-adjusted prevalence of bilateral blindness was 3.2%, which was exclusively due to glaucoma in 9 (22.0%) of 41 cases.

Primary and secondary glaucoma constitute a significant public health problem in rural Zululand. The prevalence and types of glaucoma vary among different black populations.