Eight-Year Incidence of Open-Angle Glaucoma in the Tema Eye Survey

To determine the incidence of open-angle glaucoma (OAG) and its risk factors in the Tema Eye Survey in Ghana, West Africa.

Longitudinal, observational population-based study.

One thousand two hundred five of 1500 participants 40 years of age or older selected randomly from 5603 participants originally drawn from the population and who had undergone a baseline examination.

All participants underwent baseline and follow-up ophthalmologic examinations 8 years apart. Glaucoma diagnosis was determined based on the International Society for Geographical and Epidemiologic Ophthalmology criteria.

Incidence and odds ratio (OR).

The response rate was 80.3%. Of 1101 nonglaucomatous participants at baseline who had complete follow-up data, 4.6% (95% confidence interval [CI], 3.7%-5.2%) demonstrated OAG over the 8-year period, or 0.58% (95% CI, 0.4%-0.8%) per year. The 8-year incidence increased with age from 3.1% in those 40 to 49 years old to 7.0% in those 60 to 69 years old. Baseline risk factors for incident OAG were male gender (OR, 2.1; 95% CI, 1.1-4.0; P = 0.025), older age relative to those 40 to 49 years old (those 50-50 years old: OR, 2.6; 95% CI, 1.2-5.7; those 60-69 years old: OR, 4.3; 95% CI, 2.0-8.8; and for those 70 years of age and older: OR, 6.3; 95% CI, 2.6-15.4; all P < 0.001), higher intraocular pressure (IOP; OR, 1.4; 95% CI, 1.1-1.8; P < 0.001), larger vertical cup-to-disc ratio (OR, 5.8; 95% CI, 5.2-6.6; P < 0.001), and thinner central cornea (OR, 1.2; 95% CI, 1.03-1.5; P = 0.013). A separate analysis performed with central corneal thickness-based IOP correction did not change the outcome of the associative model of incident glaucoma.

The incidence of OAG is higher in this population than reported in nonblack populations outside Africa. This is important not only in Ghana and probably other West African countries but also wherever people of the West African diaspora reside. These data enhance our understanding of the epidemiologic factors of OAG in this setting and may serve as reference for public health policy and planning.