Myopia is on the rise in UK children and the number of myopic children has doubled in the past 50 years. Speaking of the world, it is estimated that by 2050 half of the world’s population will suffer from myopia. However, if we talk about the causes of myopia, one of the reasons may be family and the other related to the environment, which may be due to the fact that the child stays inside for a long time.
In most people, myopia develops from a mixture of genetic and environmental factors. But there is some evidence that the modern lifestyle can also be a cause of myopia. Although scientists are still not sure exactly why this is happening. For example, research suggests that the time a child spends outside the home can play a significant role in their risk of developing nearsightedness.
Researchers still don’t know why
Most studies show that children who spend more time outside the home are less likely to develop nearsightedness. Likewise, children who spend more time outside the home during school hours have a lower rate of onset of myopia than children who do not spend time outside the home. But researchers still don’t know why. One theory is that higher levels of light outside than inside cause more dopamine to be released in our retinal receptors (the nerves that process light signals in the eye), making myopia less sensitive.
Another suggestion is that a lot of physical activity that children usually do outside of the home prevents the development of visual impairment in their eyes. However, studies also show that its effect is much less. It has also been suggested that what we see inside and outside the home can also be a factor in vision loss. For example, one study suggests that just an indoor environment and looking at walls can lead to visual impairment. Perhaps this is why myopia is more common in urban areas.
However, more research is needed to understand this. Modern way of life It is true that in the modern way of life, we often have to spend a lot of time indoors. For example, the school leaving age is now higher than ever and the number of high school students has also increased, forcing children to spend more time in formal education, which can be a cause of visual impairment. . However, it is still unclear which aspects of formal education increase the risk of visual impairment. Reading for long hours, watching things very closely, spending more time indoors, and using the screen more can all be responsible for this.
Children spend at least 40 minutes a day outside the home
Meanwhile, a study suggests that reading a book at a distance of more than 25cm from the eyes may increase the risk of developing visual impairment, although the effect of reading on the development of vision loss has been observed. turned out to be very weak. There are also different risk factors for visual impairment from high screen use in children – perhaps because screen use is difficult to predict and control over long term use. Despite this, more research is needed to understand whether it’s okay to blame the excessive use of screens for the high rates of vision loss, and if the answer is yes, then why.
Given the risk factors for developing vision loss, there are now also concerns that restrictions on staying at home during the pandemic and learning at home could worsen children’s vision. While there are no studies on its effect on children in the UK, preliminary results elsewhere suggest the outbreak may cause more children to develop visual impairment – but there is speculation that the effect will be less. It remains to be seen whether the pandemic can lead to a permanent increase in vision loss. Right now, the best advice for reducing the risk of visual impairment in children is to spend at least 40 minutes a day outdoors.
Author: Nima Ghorbani Mojrad, Senior Lecturer in Optometry, University of Bradford