Myopia is an eye defect resulting from the focus of light in front of, instead of on, the retina. This causes distant objects to be blurry, while close objects appear normal.
The eye condition is a leading cause of visual impairment worldwide. Symptoms may include headaches and eye strain.
Researchers from the University of Bristol and Cardiff University set out to determine whether education is a direct (causal) risk factor for myopia, or myopia is a causal risk factor for more years in education.
The researchers say their study provides “strong evidence” that more time spent in education is a risk factor for myopia, and that the findings “have important implications for educational practices”.
According to the report, many studies have reported strong links between education and myopia, but it is not clear whether increasing exposure to education causes myopia.
Using a technique called Mendelian randomisation, the researchers analysed 44 genetic variants associated with myopia and 69 genetic variants associated with years of schooling for 67,798 men and women aged 40 to 69 years from the UK Biobank database.
In a linked editorial, Ian Morgan at the Australian National University and colleagues say the evidence suggests that it is not only genes but environmental and social factors that may have major effects on myopia.
“Early onset allows more time for myopia to progress to high and potentially pathological myopia,” they warn, adding that education systems “must change to help protect the visual health of future generations”.
The study was published by the BMJ.