Despite current beliefs, the degenerative eye condition age-related macular degeneration is a common cause of vision impairment and blindness in sub-Saharan Africa, requiring an urgent review of vision services, according to a study by international researchers published in this week's PLOS Medicine.
Researchers from Kenya, Rwanda, and the UK, currently led by Andrew Bastawrous from the International Eye Centre at the London School of Hygiene & Tropical Medicine, found that age-related macular degeneration (a gradual deterioration of part of the retina) was the cause of blindness in 10% of people aged over 50 years in the Nakuru district of Kenya, which includes members of all 42 tribes residing in Kenya.
The researchers reached these conclusions by doing detailed eye examinations in randomly selected groups of 50 people aged over 50 years in the Nakuru District of Kenya between 2007 and 2008.
The authors found that the detection of age-related macular degeneration varied according to the type of eye examination: among the 3304 people who were examined by digital photography, 1.2% had advanced age-related macular degeneration and 11.2% had an earlier stage of the disease. When using the slit lamp technique, the standard tool used by an ophthalmologist, of the 4312 people examined, 6.7% were in the early stages of age-related macular degeneration and 0.7% had an advanced stage of the condition. Overall, the authors found that the rate of the condition increased with age but that slit lamp examination missed identifying the condition by a factor of 1.7 in relation to digital imaging, a more sophisticated technique.
Importantly, the authors found that in the people with any form of age-related macular degeneration, a quarter had some visual impairment and overall, 10% of blindness was caused by the condition.
The authors say: "Despite the long held belief that age-related macular degeneration is not a public health concern in Africa, this study provides evidence not only that age-related macular degeneration is as prevalent as in some other world regions, 12.4% in this population, but also that it is an important problem contributing to both visual impairment and blindness in Africa."
They continue: "Low vision services remain a hugely neglected area of care on the African continent; strengthening these services might be a cost-effective use of limited resources in the interim period."
The authors add: "There is a need to train African-based ophthalmologists to improve recognition and treatment of age-related macular degeneration, particularly neovascular age-related macular degeneration, and a need for research to support the development of treatment programmes that are affordable and deliverable in Africa."
Funding: This study was supported by funding from: British Council for the Prevention of Blindness (BCPB) and the Fred Hollows Foundation (to WM). AB is funded by a Medical Research Council and Fight for Sight Fellowship and is in receipt of an International Glaucoma Association Award Fellowship and funding from BCPB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Citation: Mathenge W, Bastawrous A, Peto T, Leung I, Foster A, et al. (2013) Prevalence of Age-Related Macular Degeneration in Nakuru, Kenya: A Cross-Sectional Population-Based Study. PLoS Med 10(2): e1001393. doi:10.1371/journal.pmed.1001393
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International Centre for Eye Health
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London School of Hygiene