Myopic and hyperopic refractive error in adults: an overview.

This article provides an overview of the recent epidemiologic findings on myopic and hyperopic refractive error in adults. Refractive errors are common conditions with high costs associated with their correction and a cause of public health and economic concerns. Myopia and hyperopia, the most common types of refractive error, are complex multifactorial conditions with prevalences that vary across populations of different ancestral origins. Recent studies have demonstrated consistently that longitudinal changes in refractive error occur and may be part of an aging process. A cohort effect also has been demonstrated in some populations, indicating that observed changes may be due to both longitudinal changes and changes across birth cohorts. The increase in myopia at older ages appears to be due to associations with other ocular conditions such as cataract. This overview highlights major findings from recent population-based studies of persons 40 years and older on 1) the importance of uncorrected refractive error as a cause of visual impairment and 2) the epidemiology of myopic and hyperopic refractive error, regarding their prevalence, changes over time and longitudinally and associated factors. Suggestions for future directions and opportunities to advance the understanding of the epidemiology of refractive errors in adults are offered.