By Thomas John Naduvilath, PhD
Brien Holden Vision Institute
Given the already high prevalence of myopia in many parts of the world, estimates of the future prevalence of myopia is critical for understanding and deploying resources to tackle the burden. In this article, the authors conducted: a) a systematic review and meta-analysis to understand the prevalence of myopia up to 2010 and b) estimated the temporal trends of global and regional prevalence of myopia and high myopia to 2050.
Review of 145 studies from 1995 to 2015 was undertaken. Myopia was defined as spherical equivalent (SE) of -0.5D or worse and high myopia was SE -5D or worse. Data on myopia prevalence by age (5-year age groups) and region (urban-rural) data were grouped to the 21 Global Burden of Disease regions. Thereafter, future temporal trends in prevalence were estimated using a 2-part linear function that included age and baseline prevalence.
The results indicate that in 2010, 28.3% and 4.0% of the global population were myopic and high myopic respectively and in 2050, will rise to affect 49.8% (4.8 billion people) and 9.8% (938 million people) of the global population respectively. Said simply, in 2050, 1 of every 2 persons will have myopia and 1 of every 10 persons will have high myopia. Significantly, regional differences are found, with high-income countries of Asia-Pacific recording the highest prevalence (48.8%) in 2010 and estimated to continue to have the highest prevalence (66.4%) in 2050. Similarly, East & Southeast Asian countries are also estimated to have prevalence >60% in 2050 whereas North America is estimated to have prevalence over 50%.
Furthermore, the study reports a significant future shift in age specific prevalence. In 2000, myopia prevalence was greater in the younger population (15-39 yrs) compared to the rest. Fast forward to 2050, myopia prevalence is estimated to be high across all ages from 15 to 79 years due to aging of the current generation of myopes combined with the future generation of younger myopes.
This future rise in myopia prevalence has significant implications for provision of eye care services and management of myopia. It is suggested that if the trends continue, myopia could become the leading cause of blindness worldwide by 2050.
Although there were some limitations to the analysis, such as paucity of prevalence data or varying definitions for myopia, the article provides a clear evidence for a rising global prevalence of myopia.
Purpose: Myopia is a common cause of vision loss, with uncorrected myopia the leading cause of distance vision impairment globally. Individual studies show variations in the prevalence of myopia and high myopia between regions and ethnic groups, and there continues to be uncertainty regarding increasing prevalence of myopia.
Methods: We performed a systematic review and meta-analysis of the prevalence of myopia and high myopia and estimated temporal trends from 2000 to 2050 using data published since 1995. The primary data were gathered into 5-year age groups from 0 to 100, in urban or rural populations in each country, standardized to definitions of myopia of -0.50 diopter (D) or less and of high myopia of -5.00 D or less, projected to the year 2010, then meta-analyzed within Global Burden of Disease (GBD) regions. Any urban or rural age group that lacked data in a GBD region took data from the most similar region. The prevalence data were combined with urbanization data and population data from United Nations Population Department (UNPD) to estimate the prevalence of myopia and high myopia in each country of the world. These estimates were combined with myopia change estimates over time derived from regression analysis of published evidence to project to each decade from 2000 through 2050.
Results: We included data from 145 studies covering 2.1 million participants. We estimated 1406 million people with myopia (22.9% of the world population; 95% confidence interval [CI], 932-1932 million [15.2% – 31.5%]) and 163 million people with high myopia (2.7% of the world population; 95% CI, 86-387 million [1.4% – 6.3%]) in 2000. We predict by 2050 there will be 4758 million people with myopia (49.8% of the world population; 3620-6056 million [95% CI, 43.4% – 55.7%]) and 938 million people with high myopia (9.8% of the world population; 479-2104 million [95% CI, 5.7% – 19.4%]).
Conclusions: Myopia and high myopia estimates from 2000 to 2050 suggest significant increases in prevalences globally, with implications for planning services, including managing and preventing myopia related ocular complications and vision loss among almost 1 billion people with high myopia.
Source: Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S. (2016). Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology; 123(5):1036-42.
Graphs: Figure 1: Graph showing GBD regions with estimated high (>55%) and low (<30%) myopia prevalence by 2050