Video: Hitting the books hurts your eyesight

Myopia - more commonly known as short-sightedness - is a visual condition that means you have trouble seeing into the distance. It’s very common, affecting at least 10 per cent of people (with estimates in several countries, including parts of Asia, significantly higher). It often runs in families, but environmental factors can influence the development of short-sightedness too. Spending a lot of time reading or watching screens, as well as limited exposure to the outdoors and natural light, can make myopia more likely. Of course, you spend a lot of time reading when you’re studying. Does that then mean that people with a higher educational attainment are more likely to have myopia?

That’s what researchers in this British study sought to find out. Several studies had suggested there was an association between how many years someone studied and their likelihood of developing myopia, but this study went further, attempting to see if there was a causal link between the two. Among 70,000 people, it looked at their eyesight and years of study - but also considered genetic factors that might make them more likely to have bad eyesight and to pursue higher education (for example, genetic variants linked to higher intelligence). Then, using a sophisticated mathematical model, they were able to check the extent to which years of education drove the risk of short-sightedness higher.

Unsurprisingly, they found that higher levels of education are associated with myopia. But more than that, the study showed that every year spent in higher education caused more short-sightedness. It wasn’t as strong as the causal links between certain genes and myopia, but it was still present - and it was definitely higher education causing myopia, and not the other way round.

Implications

So does this mean you should abandon study to protect your eyesight? We hope not - especially when higher learning’s equally been shown to have a host of benefits, including delaying the onset of dementia. But the authors suggest that since myopia often starts young, it’s important to do what you can with children to protect their eyesight. This area needs more research, but limiting screen time and ensuring kids spend enough time outside have been linked with improved outcomes when it comes to eyesight health.

References

Mountjoy, et al. (2018). Education and myopia: assessing the direction of causality by mendelian randomisation. BMJ doi: 10.1136/bmj.k2022.