Myopia: a growing global problem with sight-threatening complications

Globally, myopia is the leading cause of distance refractive error, affecting 1.45 billion or 27% of the world’s population in 2010 (myopia being defined as more than or equal to 0.50 D of myopia).1 The number of people with myopia is expected to continue to rise both in absolute numbers and as a percentage of the population.2 In certain age groups in several Asian countries, the prevalence of myopia is over 80%. Among late teenagers and young adults in Korea, Taiwan and China the prevalence is now between 84% and 97%.3–5 In addition to the increase in prevalence, there is evidence of a rise in the severity of myopia.3 A study by Vitale et al.6 in the United States found that the prevalence of moderate myopia, defi ned as between –2.00 D and –7.9 D, nearly doubled (from 11.4% in 1971–1972 to 22.4% in 1999–2004), and that the prevalence of high myopia, which was defi ned as more than 8.00 D of myopia for this study, had increased eightfold during the same period (from 0.2% to 1.6%). The global prevalence of high myopia (commonly defi ned as greater than or equal to 5.00 D of myopia) was 2.9% (224 million people) in 2010.7