Purpose
To examine the prevalence of myopia in Europe, investigate whether it is becoming more common, and to explore whether this can be explained by increasing levels of education.
Methods
Refractive error data were analysed from 13 population-based cohorts of the E3 Consortium, collected between 1990 and 2012. Mean spherical equivalent (SE) of the two eyes was calculated. Participants reporting cataract, retinal detachment or laser refractive surgery were excluded. Myopia was defined as ≤-0.75 D and high myopia as ≤-6 D. Sequential random effect meta-analyses were performed with age stratification. Geographical differences were examined according to the United Nations Geoscheme. The effects of birth year and education level were investigated, stratifying participants into primary (<16 leaving education), secondary (16-19) or higher education (≥ 20).
Results
SE was available for 58,999 subjects with median cohort ages 44-78 years, 57.9% female and minimal ethnic variation (99% European ancestry). Overall myopia prevalence was 23.8% (95% CI 19.3-28.4) with high myopia affecting 2.1%. Myopia was more common in younger subjects; 42.3% (95% CI 38.7-45.9) aged 20-30 years, compared to 29.0% (95% CI 24.8-33.2) aged 50-60. Prevalence of myopia did not differ by geographical area. A cohort effect for rising myopia prevalence was apparent; in those aged 55-60 born between 1930-39, 22.6% (95% CI 20.2-25.0) were myopic, increasing to 25.4% (95% CI 23.9-26.9) if born between 1940-49 and to 33.0% (95% CI 30.3-35.7) if born between 1950-59. Education level and birth year both affected myopia prevalence [Figure 1]; compared to a reference group of primary education and 1930-39 birth year, participants with higher education had a two-fold increase in myopia prevalence and a three-fold increase in those with higher education and born between 1950 and 1959.
Conclusions
A quarter of subjects in population-based cohorts across Europe are myopic, higher in younger subjects. There appears to be a cohort effect of increasing myopia prevalence. Education is strongly associated with myopia and education levels have risen, but the length of time in education does not fully explain the cohort effect. Further research is required to investigate if the cohort effect is explained by changes in educational experience and other factors.
Keywords: 605 myopia •
463 clinical (human) or epidemiologic studies: prevalence/incidence •
464 clinical (human) or epidemiologic studies: risk factor assessment