Prevalence and associated factors of vision loss in the South African National Health and Nutrition Examination Survey (SANHANES-1)

BACKGROUND: Vision loss is a major public health concern that significantly affects developing countries, including South Africa. Although existing literature have reported on the prevalence, causes, and impact of vision loss on the quality of life of affected individuals (children and adults) in parts of South Africa, there is no evidence of the prevalence and associated factors of vision loss in the general population. Hence, this study aimed to determine the prevalence of vision loss and its associated factors in South Africa using a population-based survey. METHODS: Secondary analyses were conducted using data from the South African National Health and Nutrition Examination Survey (SANHANES-1), a population-based national health survey conducted from 2011 to 2012. Vision loss was defined as presenting visual acuity (PVA) worse than Snellen 6/12 in the better eye. Visual acuity was assessed by clinicians and participants' subjective response to vision-related questions. Univariate and multiple logistic regression models were used to examine the association of the independent variables with vision loss. RESULTS: The analytic sample comprised 4346 individuals with a mean age of 39.1 years. Female sex accounted for 55.6% of the participants. The prevalence of vision loss among participants was 9.2% (95% CI: 7.7-10.9). Older age (45-54 years, OR = 2.99, p < 0.001; 55-64 years, OR = 5.78, p < 0.001 and ≥ 65 years, OR = 5.12, p < 0.001), female sex (OR = 1.50, p = 0.016), and previous diabetes diagnosis (OR = 2.28, p = 0.001) were significantly associated with increased odds of vision loss. Further, secondary school education (OR = 0.71, p = 0.031), white ethnicity (OR = 0.11, p = 0.007), residing in Mpumalanga province (OR = 0.12, p < 0.001) and having never had an eye examination (OR = 0.56, p = 0.003) were significantly associated with reduced odds of vision loss. CONCLUSION: Almost one in ten participants had vision loss. Adopting strategies targeted at reducing barriers to the utilization of eye care services will promote early detection and management of blinding conditions, and thereby, decrease the burden of vision loss in South Africa.