THE PREVALENCE OF PRIMARY ANGLE-CLOSURE GLAUCOMA AND OPEN-ANGLE GLAUCOMA IN MAMRE, WESTERN CAPE, SOUTH-AFRICA

Objective: To determine the prevalence of primary angle closure glauco ma in the so-called Cape people of mixed ethnic background. Design: A population-based prevalence study. Settings: Mamre, a village near Cap e Town, South Africa. Participants: Individuals aged 40 years or older . Historically, their ancestors were Southeast Asians and indigenous A fricans and, to a lesser extent, Europeans. Of a total of 1194 people, 987 (82.7%) were examined. Main Outcome Measure: Primary angle closur e glaucoma was diagnosed in individuals with previous acute or intermi ttent symptoms of angle closure and in individuals with an ''occludabl e'' angle and an intraocular pressure of greater than 21 mm Hg or a gl aucomatous visual field. Main Results: An age-related trend toward hyp ermetropia was found, which was greatest in women older than age 50 ye ars. Gonioscopy identified Shaffer grade 1 angles in 89 (9%) of 987 su bjects. The prevalence of primary angle closure glaucoma was 2.3% (23 subjects) and increased with age in both sexes. Women were affected mo re than four times as often as men and the sex difference persisted ac ross all age groups. In comparison, the prevalence of primary open ang le glaucoma was 1.5% (15 subjects). Primary glaucoma (angle closure pl us open angle) was the leading cause of bilateral blindness in the com munity, with a prevalence rate of 0.5% (five subjects). Conclusions: T his study identified primary angle closure glaucoma as a significant p ublic health problem in the Western Cape Province. Because of the ethn ic background of the people studied, these findings may also apply to the populations of Southeast Asia.