Myopia increasing in Europe

May 20, 2015

The incidence of myopia in Europe is increasing and the condition is more prevalent in those born more recently than in older generations, according to a meta-analysis of population-based, cross-sectional studies from the European Eye Epidemiology (E3) Consortium.

The incidence of myopia in Europe is increasing and the condition is more prevalent in those born more recently than in older generations, according to a meta-analysis of population-based, cross-sectional studies from the European Eye Epidemiology (E3) Consortium.

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The meta-analysis, which was led by researchers at King's College London, examined the results of 15 studies totaling more than 60,000 individuals. It was published in Ophthalmology.

The major finding was that while about one-quarter (24.3%) of the overall European population suffers from myopia, the condition is nearly twice as common in younger people: nearly one-half (47%) of those of aged between 25 and 29 years have myopia.

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In their meta-analysis of 61,946 adults, the researchers obtained noncycloplegic refraction, year of birth, and highest educational level achieved from all of the participants. For the purposes of this analysis, myopia was defined as a mean spherical equivalent of ≤−0.75 diopters.

The researchers performed a random-effects meta-analysis of age-specific myopia prevalence. Sequential analyses were stratified by year of birth and by the participants’ highest level of education attained.

Next: The findings

 

Their findings:

• The overall myopia prevalence was 24.3% (95% confidence interval [CI], 20.1–28.5); the age-standardized prevalence of myopia in Europe was 30.6% (95% CI, 30.3–30.8).

• The age-stratified analyses revealed a prevalence in young adults aged 25 to 29 years of 47.2% (95% CI, 41.8–52.5) compared to a prevalence of 27.5% (95% CI, 23.5–31.5) in those aged 55 to 59 years.

• Gender was not a factor in prevalence of myopia.

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• Although there is a significant cohort effect for increasing prevalence of myopia among more recent birth decades, the trend does not appear to be a new phenomenon: age-standardized myopia prevalence was from 17.8% (95% CI, 17.6–18.1) among those born between 1910 and 1939 compared to 23.5% (95% CI, 23.2–23.7) among those born between 1940 and 1979.

• Myopia prevalence increased with higher education levels. The age-standardized prevalence for those who completed primary education was 25.4% (CI, 25.0–25.8), compared to 29.1% (CI, 28.8–29.5) for those who completed secondary education and 36.6% (CI, 36.1–37.2) for those who completed higher education.

• Education levels did not fully explain the cohort effect; rather, individual associations of educational level and birth cohort had an additive effect on myopia prevalence.

Next: Assessment

 

The researchers noted that although factors associated with increased education, such as less time spent outdoors, more time spent studying, and increased use of computers, tablets, and smartphones may help explain the correlation between myopia and educational levels, the rising levels of education are not solely to blame. They suggested that more research is required to see if changing trends in childhood outdoor exposure and educational practices are affecting myopia prevalence. They noted that a number of factors increase the risk for myopia, including family history.

They concluded that the increasing prevalence of myopia has implications for both the health care system and the economy.

“Increasing levels of myopia carry significant clinical and economic implications, with more people at risk of the sight-threatening complications associated with high myopia,” the researchers wrote. “The major strength of our study is the large sample size contributing to the prevalence estimates, providing a unique opportunity to estimate the burden of refractive error in middle and older aged individuals across Europe. This is beneficial for planning of clinical services and raises awareness, for both clinicians and economists, of the future potential issues of rising myopia levels and associated visual impairment.”

The E3 Consortium is a collaborative network of epidemiological studies of common eye diseases in adults across Europe. Refractive data were available for 61,946 participants from 15 population-based studies performed between 1990 and 2013.