Myopia — the medical term for short-sightedness or near-sightedness — is on the rise. Globally, around a third of people were short-sighted in 2020, according to the World Health Organization (WHO). But projections indicate that 3.4 billion people will be short-sighted by 2030, or about 4 in 10, rising to half the population by 2050.
Short-sightedness may not appear to be a significant problem initially – after all, the symptoms are easily corrected with glasses or contact lenses. But Myopia is the leading cause of vision impairment and the second highest cause of blindness.
Current trends indicate that the severity of myopia is increasing, too, leading to high myopia, which is associated with developing macular degeneration, cataracts and even glaucoma retinal detachment.
Worse still, children are developing myopia at a younger age, increasing their chances of developing high myopia and its associated problems.
Then there’s the cost to communities.
Myopia can create a financial burden on countries, with more than $200 billion of global productivity losses every year. And if left uncorrected, it negatively impacts the quality of life and contributes to poor academic performance in children.
But why are cases of myopia on the rise, and what can be done to slow or even reverse it?
Growing up indoors
The rapid increase in myopia cases around the world rules out any genetic reasons, which has left scientists to explore more environmental factors for answers. And the answers appear to be centred around education — or a side effect of it — and spending time outdoors.
The older you are, the more likely you were to have spent more time playing outside as a child. But many 21st century children are experiencing a vastly different childhood from their parents, with increasing numbers of people living in cities and parents are more likely to keep their children inside for reasons of safety.
COVID-19 has certainly not helped either, and during lockdowns, children spent even less time outdoors than they had before, and more time on screens. This had the effect of accelerating myopia progression, especially in younger children.
Singapore understands the problem better than most — having some of the highest levels of near-sightedness in the world — and has undertaken numerous studies since 2001 to resolve the growing issue. As well as the usual efforts to encourage regular check-ups for children as young as pre-school level, the guidance is also to spend time doing activities outdoors, which “can prevent or delay the onset of myopia”.
Why does being outdoors help your vision?
Researchers are still working out exactly why being outdoors in natural lights helps prevent myopia. It could be to do with light intensity — the sun’s light is brighter than most indoor lighting, which could promote better eye growth.
It could also be linked to dopamine, which is released into the eye when sunlight comes into contact with the retina. The dopamine helps to inhibit the eye from growing too long, which is instrumental in reducing the chances of developing myopia.
Or it could be linked to Vitamin D synthesis that is triggered when going outdoors, which also inhibits myopia.
How much time outdoors makes a difference?
One recent study asked primary schools in Shanghai, China to allocate an additional 40-80 minutes of extra outdoor time for test groups, while a control group continued their existing habits of just over two hours a day outside on average. After two years, the incidence of myopia dropped in the test groups by 11-16% compared with the control group.
Time in nature can build children’s confidence, teach responsibility, and improve happiness and concentration levels, while reducing anxiety. Even if we do not fully understand the reasons behind why being outside is so beneficial for our eyes, it is one more advantage in an already long line of health benefits to enjoying the great outdoors.
This article was originally published in the World Economic Forum.
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