Short-sightedness is on the rise - including among kids. Here's what can be done

Myopia – the medical term for short-sightedness or near-sightedness – is on the rise. And perhaps most worryingly, this trends also affects children.

Around 2.6 billion people were short-sighted in 2020, according to the World Health Organization (WHO), which anticipates that this figure will rise to 3.4 billion by 2030.

Meanwhile, a third of children and adolescents globally are affected by myopia, according to a recent study published in the British Journal of Ophthalmology (BJO).

Short-sightedness initially may not appear to be a significant problem – after all, the symptoms are easily corrected with glasses or contact lenses. But myopia is in fact a leading cause of vision impairment and can lead to blindness.

Current trends indicate that the severity of myopia is increasing, too, leading to something called 'high myopia', which is when myopia progresses to the point of putting a person at risk of macular degeneration, cataracts and even glaucoma retinal detachment.

Children are developing myopia at a younger age, increasing their chances of developing high myopia and its associated problems. The BJO study found that short-sightedness in children tripled between 1990 and 2023, and that the increase was 'particularly notable' after the COVID-19 pandemic.

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.

The BJO study found that developing countries were predicted to have 40% of people short-sighted by 2050. The World Economic Forum's Global Health and Healthcare Strategic Outlook aims to address health disparities of this kind. It sets out a vision for 2035 based on four pillars of equitable access, healthcare-systems transformation, technological innovation and environmental sustainability, with equity as the foundational goal.

But why are cases of myopia on the rise - and what can be done to slow, or even reverse, the trend?

The rapid increase in myopia around the world rules out genetic causes, which has led scientists to search for answers among environmental factors. Some of the answers appear to be related to education – or a side-effect of it – and spending time indoors.

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 more likely to keep their children inside for reasons of safety.

COVID-19 has not helped: during lockdowns, young people spent even less time outdoors and more time on screens. This had the effect of accelerating myopia progression, especially in younger children.

Singapore understands the problem better than most. It has some of the highest levels of near-sightedness in the world and has undertaken numerous studies since 2001 to resolve the 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'.

Researchers are still working out exactly why being outdoors in natural light 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 myopia.

Or it could be linked to Vitamin D synthesis, which is triggered by spending time in natural light, and this also inhibits myopia.

One study asked primary schools in Shanghai, China to allocate an additional 40-80 minutes of outdoor time for test groups, while a control group continued their existing habits of just over two hours a day outside. After two years, the incidence of myopia dropped in the test groups by 11-16% compared with the control group.

"There is something about being outside that is a real benefit to children," said Daniel Hardiman-McCartney, clinical adviser from the UK College of Optometrists, in an interview with the BBC. Whether it's due to sunlight, exercise or the opportunity for children's eyes to focus on distant objects, the benefits for eyesight are clear. So much so that myopia experts recommend that children (particularly those aged seven to nine) spend at least two hours a day outside.