Exfoliation syndrome in sub-Saharan Africa

The goal of this review is to estimate the burden of exfoliation syndrome (XFS) and exfoliation glaucoma (XFG) in sub-Saharan Africa and to identify the gaps in knowledge of disease prevalence in this region. PubMed, Medline, African Journals Online and Google engine search were carried out using the following terms "pseudoexfoliation" or "exfoliation syndrome Africa", "pseudoexfoliation" or "exfoliation syndrome" + "glaucoma Africa," "glaucoma prevalence Africa," "pattern of glaucoma presentation Africa," "pseudoexfoliation" or "exfoliation syndrome" + "cataract Africa," "ophthalmic conditions Africa." Studies were included if they described the proportion or prevalence/incidence of XFG and XFS in sub-Saharan Africa or if they investigated lysyl oxidase-like 1 (LOXL1) variants in XFS among Africans. 22 papers were identified and classified as clinic-based studies (n = 16) and population-based (n = 4) studies. Two other studies were considered important, and therefore, included in the review. Clinic-based studies demonstrate that XFS is a common cause of glaucoma, as is true in many other parts of the world. Furthermore, XFS often co-exists with cataract and climatic droplet keratopathy. Its prevalence ranged from 5.1 to 7.7 % in patients >40 years in population-based studies, a value that is considerably higher than that reported in African Americans. XFS was strongly associated with increasing age in the prevalence studies. The burden of XFS in sub-Saharan Africa is high. More investigation is needed to determine why clinic-based studies report virtually no XFS in some countries (Ghana and Tanzania), while nearby countries report greater proportions (Nigeria and Ethiopia).