Exfoliation syndrome in black South Africans

Abstract

Background: Data on exfoliation syndrome (XFS) in Africans are scarce.

Objective: To determine the prevalence and clinical features of XFS among black South Africans.

Design: Random cross-sectional samples of the black population aged 40 years or older from 2 districts in South Africa: Hlabisa, in northern KwaZulu-Natal Province, and Temba, North West Province.

Methods: Standardized examination, including slitlamp biomicroscopy with pupil dilatation, gonioscopy, pachymetry, tonometry, binocular indirect ophthalmoscopy, and visual field testing.

Results: Among 1840 participants, the prevalence of XFS was 7.7% (95% confidence interval, 5.4%-10.5%) in Hlabisa and 6.0% (95% confidence interval, 4.1%-8.4%) in Temba. The prevalence increased with age, with 18.9% (Hlabisa) and 16.5% (Temba) of those 70 or older affected. The clinical appearance was similar to that reported in other ethnic groups. Exfoliative glaucoma accounted for approximately one fourth of open-angle glaucoma cases (OAG). Open-angle glaucoma was associated with XFS; the age-adjusted and sex-adjusted odds ratios were 2.3 (95% confidence interval, 1.0-5.2) and 2.8 (95% confidence interval, 1.2-6.3) for Hlabisa and Temba, respectively. The relationship with OAG was absent when adjusting for intraocular pressure. Exfoliative glaucoma was characterized in this predominantly untreated population by high intraocular pressure and severe visual loss. Among subjects with XFS and OAG, 16 of 18 were blind in 1 or both eyes.

Conclusions: Exfoliation syndrome occurs at a high prevalence among black South Africans and incurs a moderate increase in risk of glaucoma. In this untreated population, this increased risk was dependent on raised intraocular pressure. Open-angle glaucoma in association with XFS appears to be associated with a poor prognosis.