Design of a pilot study of glaucoma in Barbados.

In Barbados, West Indies, open-angle glaucoma is a major cause of blindness, presenting early and with advanced visual loss. This report describes the design of a pilot project that evaluated the feasibility of an epidemiologic study to measure glaucoma prevalence and ascertain risk factors in this population. A major goal of the pilot project was to test the proposed sampling and recruitment methods for the larger study. The pilot project identified a random national sample of 300 persons ≥ 35 years, 100 from each of three geographic strata, who were invited to participate in a comprehensive interview and ophthalmologic examination. Because the pilot study was still ongoing at the time of this report, data are available only on the first 172 persons in the sample; 88 percent of those contacted were eligible for the study and 97 percent agreed to participate without any differential participation by geographic area. Preliminary data on the first 170 persons examined show that 20 to 25 percent of participants had best corrected visual acuity of 20/40 or worse; about 10 percent had intraocular pressure >21 mmHg; over 20 percent had cup-disc ratios of ≥0.5; and ten persons had open-angle glaucoma.