Prevalence of Presbyopia in Rural Tanzania: A Population–Based Study

Abstract

Abstract: : Purpose: Presbyopia is the most common physiologic ocular change beyond the age of 40; however, little is known about the prevalence of presbyopia in African populations, and no data exist in rural populations. The present population–based study describes the prevalence of presbyopia in rural Tanzania. Methods: A complete sample of 3 villages, and random sample of one town in the Kongwa District of Tanzania were examined. 844 town–dwellers and 865 village–dwellers aged 40 years and older were refracted and given best distance correction. Near vision was tested and corrected to the nearest 0.5 diopter. Presbyopia was defined as at least one line improvement on near visual acuity chart with addition of plus lens. Results: 61.7% of eligible participants were presbyopic. Multivariate analysis showed higher prevalence of presbyopia was associated with increased age, female gender, higher educational level, and residence in town (Odds ratio for residence= 3.09, 95% CI=2.46–3.90). The risk of presbyopia increased 16% per year of age from age 40 to 50, but non–significantly at 1% per year after age 50. More severe presbyopia was associated with female vs. male gender (mean 1.48 vs. 1.37 D, respectively, age–adjusted p–value=0.0013) and less education vs. secondary education (mean 1.47 vs. 1.17 D, respectively, age–adjusted p–value=0.03) . There was no association with refractive status or best–corrected distance acuity. Conclusions: The present study provides the first population–based data on prevalence of presbyopia in a large, random sample of older Africans and suggests a high rate of presbyopia in the adult population. Presbyopia plateaus after age 50 and is more common in females. Additionally, the finding of a three–fold increased risk in town versus village dwellers was unexpected and suggests that research into other factors, including environmental, is warranted.

Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • visual acuity • aging