Frequency and causes of visual impairment in people attending outreach clinics in Zambia

Preventable visual impairment and blindness represent significant global public health challenges. Expanding access to high-volume eye care services in underserved areas may reduce visual impairment and blindness. Visual impairment negatively impacts quality of life, education, and employability, but is often treatable with management following a basic eye examination. Access to basic eyecare in Zambia is limited. Vision Action, a UK-based non-governmental organisation, facilitates eyecare services in Zambia to reduce rectifiable visual impairment by supporting government outreach clinics in underserved communities. This study examines the frequency of presenting visual impairment, uncorrected refractive error, and ocular pathology among outreach clinic attendees in Zambia. A retrospective analysis of outreach clinic records between 2012 and 2015 was performed. The available data include patient demographics, presenting symptoms, presenting level of vision, and classification of any ocular pathology present. Levels of visual impairment were categorised according to the World Health Organization's classification for blindness and visual impairment. Data from 5809 patients were collected (58.5% female, mean age = 41.9 years, SD = 20.7 years). Presenting vision, in the better eye, was classified as ‘moderate visual impairment’ in 14.2% (<i>n</i> = 766), ‘severe visual impairment’ in 0.3% (<i>n</i> = 15) and ‘blind’ in 4.3% (<i>n</i> = 234) of individuals. Uncorrected refractive error was responsible for 62.4% and 57.0% of blindness and severe visual impairment, respectively. Cataract, corneal scarring, and glaucoma were the most common non-refractive ocular pathologies associated with visual impairment. Uncorrected refractive error is the leading cause of blindness and visual impairment in patients presenting to outreach clinics in Zambia and is particularly significant in a predominantly working-age population. Outreach clinics are an effective method of detecting and treating correctable visual impairment in this population. However, there is a need to expand and enhance primary eyecare services to reduce the burden of visual impairment, through management of uncorrected refractive error.