Studies have been observational in nature since exposing children to different levels of education in clinical trials would be unethical. The research involved more than 67,000 people from the United Kingdom who were between the ages of 40 and 69 years old.
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 proposes that a UK University graduate with 17 years in training would be one dioptre more myopic than a person who left school at 16 with 12 years of education.
Myopia, or short-sightedness, is a leading cause of visual impairment worldwide.
Many studies have reported strong links between education and myopia, but it is not clear whether increasing exposure to education causes myopia, myopic children are more studious, or socioeconomic position leads to myopia and higher levels of education. The difference is enough to mean needing glasses for driving.
Exactly how increasing levels of education cause myopia can not be known from MR analyses, although there are possible clues from recognised environmental risk factors. Young Jewish boys from these communities had a much higher rate of myopia than young girls as they received a less, comparatively.
They point to East Asia, where early intense educational pressures combined with little time for play outdoors has led to nearly 50% of children being myopic by the end of primary school, compared with less than 10% in a study of British children.
A new research based on genetic data reveals that spending more time studying in school can indeed have a negative effect on people's eyesight.
"Given the benefits of time spent open air on psychological well being and the safety it gives in opposition to weight problems and continual illnesses, we would all profit from spending extra time outdoors". They acknowledge that the people in their database were generally healthier than the general population, which could lead to bias.
The study, after taking into account a number of influential factors suggested that for every additional year of education was associated with more myopia. It is not known whether "Bright Light" classrooms provide protection against myopia and replicate the effects of increasing time spent outdoors and the research team suggest that future studies could look at whether this intervention works against myopia. But there was insufficient evidence that this could explain the findings.