Prevalence and types of glaucoma among an indigenous African population in southwestern Nigeria.

Purpose

To determine the prevalence and identify the types of glaucoma in the Akinyele district of Oyo State in southwestern Nigeria.

Methods

Residents of Akinyele district of Oyo State in southwestern Nigeria aged 40 years and older were randomly selected in a stratified manner. All participants underwent comprehensive ophthalmic examination, including visual acuity assessment, anterior segment biomicroscopy, IOP measurement, gonioscopy, optic nerve head and disc evaluation, and central visual field assessment. Glaucoma was diagnosed using the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) classification scheme.

Results

A sample of 811 subjects (90% response rate) was examined. The crude prevalence of all forms of glaucoma was 7.3% (95% confidence interval [CI] 5.5%-9.1%) with an age and sex standardized rate of 6.9% (95% CI 6.88%-6.92%). Primary open angle glaucoma was found in 6.2% (95% CI 4.5%-7.8%) and primary angle closure glaucoma in 0.2% (95% CI 0.0%-0.6%). Secondary glaucoma accounted for 0.9% of the cases, with couching and neovascular process being the main causes (0.2% each). Prevalence of glaucoma increased significantly with increasing age (P for trend < 0.05).

Conclusions

The high prevalence of glaucoma (7.3%) in the Akinyele district in southwestern Nigeria is comparable with those in predominantly black populations in the Akwapim-South district of Ghana and Barbados. Primary open angle glaucoma remains the most prevalent form of glaucoma.