Are More Educated People More Likely To Be Short-sighted?

New UK research has found that individuals who spend more time in education could have a greater risk of becoming short-sighted.

Carried out by researchers at the University of Bristol and Cardiff University, the study set out to determine whether education is a direct (causal) risk factor for short-sightedness, also known as myopia, or whether myopia is a causal risk factor for more years in education. The team gathered data from 67,798 men and women aged 40 to 69 years who were taking part in UK Biobank, a large, long-term study which looks at conditions such cardiovascular disease (CVD) and cancer incidence in thousands of UK residents.

The researchers analyzed the data for 44 genetic variants associated with myopia and 69 genetic variants associated with years of schooling using a technique called Mendelian randomization. This type of analysis gives more reliable results, therefore if an association is found it is more likely to suggest a direct relationship. After taking into account potentially influential factors, the team found that every additional year of education was associated with more myopia, or more specifically, a refractive error of -0.27 diopters a year.

This would mean that a UK university graduate with 17 years of education would, on average, be at least -1 diopter more myopic than someone who left school at 16 with 12 years of education, a level of myopia that would require glasses for driving. However, there was little evidence to suggest that myopia was a causal factor for staying in education for longer.

The researchers did note that their study had some limitations, for example participants taking part in UK Biobank are known to be more highly educated, have healthier lifestyles, and report fewer health problems compared with the general UK population, which may have affected the results. However, they added that there was still little evidence that this could explain their findings, and that the study provides "strong evidence" that more time spent in education is a risk factor for myopia. "Early onset allows more time for myopia to progress to high and potentially pathological myopia," they warned, adding that education systems "must change to help protect the visual health of future generations."

Myopia is a leading cause of visual impairment worldwide. Currently, 30-50% of adults in the United States and Europe are myopic, with levels of 80-90% reported in school leavers in some East Asian countries. A linked editorial also added that in East Asia almost 50% of children are myopic by the end of primary school compared with less than 10% in a study of British children, possibly due to a combination of intense educational pressure early in childhood and little time for outdoor play. Evidence has already shown that outdoor light can have a protective effect against the development of the condition.

A study published just last month by the University of Edinburgh which looked at more than 300,000 participants also found that needing to wear glasses is linked to a higher level of intelligence.