Glaucoma in Zulus

Abstract

To determine the prevalence and the main types of glaucoma in a representative adult population in rural Zululand, and to describe the distribution of glaucoma-related variables in healthy subjects and those with glaucoma.

Prevalence of Glaucoma in an Urban West African Population

“…However, because this criterion alone produced a high rate of false-positive results, the cutoff for referral was changed to a CDR greater than 0.725 part way through the study. This decision was supported by known statistically normal upper limits for CDRs in other African glaucoma prevalence studies that reliably determined CDRs 18,20–22 and results from the current study indicating that a vertical CDR (VCDR) of 0.725 represented the 97.5th percentile cutoff in this population.…”

“…A nonrandomly collected survey of 1843 Ghanaians 30 years and older found a similar result. 17 In developing regions in Africa and South Asia, the percentage of undiagnosed glaucoma in the population studied has been reported to be greater than 90% 17,20–22,39–41 compared with studies in developed countries, which reveal the rate of undiagnosed glaucoma to be approximately 50% to 75%. 3–5,33–38 It is unclear whether this is related to differences in methods for identifying glaucoma or overall access to eye care professionals in developing vs developed countries or to improved efforts to screen high-risk populations in the developing world.…”

“…3 The South African urban and rural surveys found a higher age-adjusted prevalence of all glaucomas in men than in women but the prevalence of POAG failed to reach statistical significance. 21,22 In the St Lucia study, 4 no difference was found in POAG prevalence by sex. Study results could vary because of differences in sample sizes, diagnostic criteria, population structures, or participation rates by age and sex.…”

“…18 There have been 3 well-conducted glaucoma surveys performed in sub-Saharan Africa 19 that were randomly sampled, were population based, and had case definitions that did not include elevated intraocular pressure (IOP) 18 : 1 in Kongwa, Tanzania, East Africa 20 and 2 in South Africa. 21,22 However, these studies yielded lower prevalences of glaucoma than those found in studies of people of African descent conducted in North America, 3–5 possibly because of the genetic heterogeneity of groups of people of African descent and the fact that most African Americans and Afro-Caribbeans are descendants of West and not East or Southern Africa. Given the considerable genetic heterogeneity in sub-Saharan African people, 23–25 it is unlikely that existing studies from East and South Africa are generalizable to all sub-Saharan African populations, such as West Africa.…”

Incidence of visual loss in rural southwest Uganda

“…Data from several studies in Africa indicate that glaucoma may be as common in Africa as in African-Americans. [20][21][22] We estimated that glaucoma had an incidence rate of 0.4 per 1000 person years, accounting for 3.6% of incident cases. However, our estimate of glaucoma is probably conservative since we included only people with established visual loss, a relatively late sequel of glaucoma.…”