More people are developing myopia. Could screen time be to blame? Photo / Getty Images
More people are developing myopia. Could screen time be to blame? Photo / Getty Images
THREE KEY FACTS
The global myopia rate tripled between 1990 and 2023, with significant risks of blindness by 2050.
Experts warn myopia should be viewed as a disease, increasing risks for ocular conditions like retinal detachment.
Key factors include lack of outdoor time and excessive “near-work”, especially in children.
Every morning – shortly after checking my phone and shortly before brushing my teeth – I pull down my lower eyelids in turn and smush a contact lens on to each of my eyeballs. I’m pretty good at this by now and can do it without a mirror.
After a heartbreaking diagnosis when I was 12 – and a genuinely tragic first pair of glasses – my vision declined throughout my teenage years, finally stabilising at -4.5 dioptres, which means that objects come into focus at 22.22cm (ie. one metre divided by 4.5) in front of my face.
My eyeballs are the wrong shape. They grew into eggs instead of perfect 24mm spheres. My increased axial length – that’s the distance from my corneas in the front to my retinas at the back – means that objects come into focus in the wrong place. Without contacts or glasses, everything is underwater.
Like most of my fellow myopes (people who are short-sighted), I have come to view this as a mild hindrance but a manageable one – as long as I keep up my £15 ($33) monthly direct debit to Specsavers. It hadn’t occurred to me until I began speaking to the world’s leading myopia experts that I suffer from a disease. Least of all a preventable disease. Least of all a disease that if left to spread at its current rate will result in millions of people going blind.
Too much screen time can increase the risk of myopia in children. Photo / 123rf
It sounds alarmist and yet when you look at the numbers, alarm feels appropriate. Necessary, even. The global myopia rate tripled between 1990 and 2023, according to a recent study in the British Journal of Ophthalmology. The World Health Organization predicts that by 2050, half of the world will need glasses and 10% will be high myopic (that’s a -6 dioptre prescription or higher), which carries severe risks of complications and even blindness.
“Myopia should absolutely be viewed less as an inconvenience and should take its proper place as a disease,” says Dr Donald Mutti, professor in optometry at Ohio State University. “Not all myopic eyes have the pathologies that threaten vision,” he stresses. “But it’s absolutely the case that myopia increases risk for ocular disease.”
Ocular diseases include cataracts, glaucoma, and the two that cause the experts most concern. One is retinal detachment, which is when vitreous fluid – the jelly inside your eyeballs – begins to leak and pushes the retina away at the back, “a bit like a bubble in wallpaper” as a leaflet from Moorfields Eye Hospital in London helpfully puts it.
Moorfields has been handing out a lot of such leaflets recently. Amid a “substantial” increase in retinal detachment surgery, the hospital recently reported a sharp increase in the proportion of myopes undergoing the treatment – from less than 10% in 2012 to more than 40% in 2023 – with the steepest rise among younger patients.
“If your retina detaches, you lose vision,” explains Dr Annegret Dahlmann-Noor, the paediatric ophthalmologist who led the Moorfields study. “It starts in the periphery and moves towards the centre and if it gets to the point where it affects your central vision, then usually recovery is not complete. We’ve seen some teenagers and people in their early 20s present with retinal detachments. It’s a trend we can see.”
The other condition that “really destroys” your vision, as she puts it, is macular degeneration. This is now the leading cause of blindness in working age people in China, explains Dr Jan Roelof Polling, who is part of the myopia working group at the Erasmus University Medical Centre in Rotterdam.
“As your eyeballs grow longer, it puts the tissues under strain,” he says. “The stretching is okay when you’re young. But when you’re older you lose collagen – and there’s lots of collagen in the eye. So now the eye is stretched but it has holes in it.”
The condition that “really destroys” your vision is macular degeneration. Photo / 123RF
Again, this is a condition that once mainly affected older people but is now hitting ever-younger patients. Unlike retinal detachment, there’s not a lot that can be done about it.
You can have injections into the eyeball to take the bleed away but that’s about it,” says Polling. “One-third of all high myopes develop myopic macular degeneration, which almost always results in visual impairment or blindness.”
One-third of all “high myopes” ... If you scale that up, you begin to see the cause for alarm. The world population is expected to be 10 billion by 2050. One-tenth of that is one billion. One-third of that is 333 million. That’s a USA of blindness.
“That’s why we’re starting to worry now,” says Polling. “You only have to look at China, where 80-90% of people have myopia and a significant proportion become blind or visually impaired within their working careers. It’s a huge worry and a huge expense for families. This will become a much bigger problem.”
At this point, you’re hopefully wondering why. Why has the world’s sight deteriorated so badly? The current estimate is that 15-20% of British teenagers are myopic, but our data-gathering isn’t nearly as good as it is in East Asia and Singapore, where this is already recognised as a dire catastrophe. In Singapore, the “myopia capital of the world”, around 80% of adults are myopic. In Seoul, South Korea, the condition affects 96.5% of 19-year-old males.
This is where we are heading, stresses Dahlmann-Noor. “We analysed hundreds of data sets last year. We used to have a rigid algorithm to find out what the underlying problem was when a 5-year-old already had myopia. We would do our diagnostic tests and we would reliably be able to find something wrong, genetically, metabolically, whatever.
“Now? If we do the same tests as before, we find children with myopia who don’t have a thing wrong with them. They only have myopia. So there is a trend for the onset of myopia to be earlier. And there is a trend for children with simple myopia coming into our NHS clinics at an earlier age.”
There is a strong genetic component to myopia. If both of your parents need glasses, you probably will too; rates of myopia are also higher in certain Asian and Afro-Caribbean populations than in white people. Still, none of this explains the rapid recent increase.
It isn’t the gene pool that’s changed, says Dahlmann-Noor: “But what has changed very dramatically are our lifestyles. We don’t simply inherit our genes from our parents – we inherit their lifestyles too.”
And here there are two factors of particular concern. One is that children are not spending nearly as much time in daylight as they need to. Daylight is thought to stimulate the release of dopamine in the retina which inhibits eyeball growth. Given that we evolved as an outdoor species but now spend around 90% of our lives indoors (that’s more time than the average whale spends underwater by the way) the idea that our eyes are struggling to cope with our low-light interiors isn’t so surprising.
The other factor is that children are spending too long engaged in “near-work”, ie. concentrating on things too close to their face and thus squeezing their eyeballs into the wrong shape from an early age.
Since myopia develops while the eyeball is still growing, the crucial window is in childhood. Hence the standard advice for children is known as the 20/20/2 rule: for every 20 minutes of near-work, spend 20 seconds focusing on something in the distance; and most importantly, spend two hours outside each day. Also, go and get your eyes tested.
So environment plays a crucial role. Much of the blame for the shockingly high rates of myopia in East Asia (notably in urban areas) seems to come down to the highly competitive education system. East Asian children start school earlier in life, work longer days, receive far more homework, and spend very little time outdoors. Similarly, in Singapore, children spend as little as half an hour a day outside (and the weather is actually nice in Singapore). One of the few East Asian countries to have seen a decline in myopia rates in recent years is Taiwan, which in 2010 introduced a policy known as Tian-Tian 120, which encourages schools to incorporate 120 minutes of time outdoors into their daily schedules.
You would think that less homework, more breaks is a message that most schoolchildren could get behind. But, it’s not solely schoolwork that’s to blame – children’s leisure time has shifted too. China also tops the global chart of hours spent playing video games each week (12.4 hours compared to the UK’s 7.2). And one of the things that Polling has noticed from studying Dutch teenagers is that it’s no longer principally the academic children who need glasses – it’s everyone.
“There has long been an association with education and myopia,” he says. “It used to be that the kids with glasses were the ones who went on to study at university – and the kids who played soccer stayed without glasses. That’s changed with people born after 2000. Everyone is on their phone.”
Dahlmann-Noor is reluctant to draw conclusions before the link between early eyeball development and devices has been more rigorously researched. However, she does stress that if children only had access to phones when they were 16 or 17, the effects on their eyesight wouldn’t be nearly as bad.
“That’s when the eyeball has reached its final state. But I have families coming into the consultation rooms who clip a smartphone on to their child’s pushchair and have Peppa Pig running. Why does a 1-year-old need to have Peppa Pig on a smartphone? But these things have invaded everyone’s private space and we don’t even notice them any more.”
We are by now fairly used to the idea that phones have made a generation of teenagers anxious, depressed, sleep-deprived, narcissistic, susceptible to terrible influencers – and the rest. The American social psychologist Jonathan Haidt lays out the evidence in grim detail in his bestseller, The Anxious Generation, and if you’re on any parental WhatsApp groups, you’ll be aware of his thesis: the wide adoption of the smartphone in 2010 plus a gradual erosion of unstructured outdoor play has prompted a teenage mental health catastrophe, resulting in higher rates of suicide and self-harm, particularly among teenage girls.
Nonetheless, the idea that these same forces might literally be destroying our children’s ability to see things clearly – might even eventually blind them – is not one that I’ve seen discussed, even in the most tech-phobic parental forums. And yet: one Danish study found double the risk of myopia in 16 to 17-year-olds who used electronic devices over six hours a day. Chinese studies have correlated axial length with time spent on both computers and phones and found that yes, there is a link.
It should be stressed, however, that experts are cautious about pushing the thesis too hard. Dahlmann-Noor points out that the myopia trend long predates smartphones. Concentrating on anything close to your face can be bad for your eyesight. Your child could be copying out The Book of Common Prayer, she could be performing a mindful colouring exercise, she could be playing Tetris on a Game Boy in 1992 or she could be doomscrolling TikTok. The eyeball would be under the same strain.
Moreover, it’s generally agreed that near-work is secondary to time outdoors as a determining factor. “If you’re looking at school-age kids from 6 or 7 or so, we have not found that near-work has the influence that people often think it does,” says Mutti. “It just doesn’t show up as that significant a factor in cohort or longitudinal studies.”
Mutti has been collecting data on behavioural patterns and myopia since 1989 and he is convinced that time outdoors is the significant factor. “It’s pretty clear that kids are spending less time outdoors than they used to,” he says. “When I was a kid, my mom would encourage us to get out of the house: ‘Come back when it’s dinner time’. But indoors is just a lot more entertaining than it used to be. Parents have more concerns about unsupervised kids running wild on the streets.”
Many of these are perfectly rational, I’d add. I’d love my children to play outside more. But my immediate urban environment is designed for cars, not children. There are very few activities for even older children to safely do outdoors that don’t require parental supervision and/or cash.
And it’s not as if time spent on screens and time spent outdoors are unrelated. If my eldest is playing football with his mates, he is, perforce, not playing Roblox. If my youngest is watching Bluey while I get some work done, this is almost certainly happening indoors.
And it’s the youngest I should be most worried about, says Mutti. Even as a “near-work sceptic”, he is extremely concerned about the effect of screens on the very young. “To me, the preponderance of evidence is not in favour of near-work being so important in school-age kids,” he says. “But could near-work influence a young child’s eyes? A pre-schooler’s eyes? That’s a valuable question to ask. In my research on refractive development, there are strong effects of near-focusing on the development of infants’ eyes – maybe into the toddler years.”
He demonstrates this to his students with balloons. “The focusing muscles act as a mechanical, tensing force at the front of the eye. If you put a squeeze around the balloon in the front, it elongates at the back. So it’s not hard to see how near-focusing could change the shape of an infant’s eye. That makes me very concerned about how toddlers are spending their time.”
And here is an “absolute difference” brought on by technology. “You no longer have to be able to read to be an intense near-worker as a toddler,” he says. “If you watch small children, they love their iPads. They’re very adept at swiping and scrolling and finding their next video even at age 2. I’m concerned about that. The intense use of electronic devices among toddlers.”
Polling adds that just because it’s harder to find a direct link between myopia and screens, it doesn’t mean it doesn’t exist. “It’s relatively straightforward to measure light exposure or even simply how much time a child is outside. It’s much harder to measure focal distance.”
But either way, it hardly seems surprising that myopia rates rapidly accelerated during the Covid-19 pandemic, during which children were both locked up indoors and forced to look at screens. Neither I nor my 11-year-old have forgotten the torture of his Year 1 Zoom lessons. Indeed, the pandemic period of 2020 to 2023 saw a “notable” increase in myopia rates. One recent Scottish study found a 42% rise in the incidence of myopia. And a recent study in Hong Kong found that myopia rates in 6 to 8-year-olds had doubled during the Covid-19 pandemic: 25% of 6-year-olds and 46% of 8-year-olds were myopic.
And it’s worth stressing again that the earlier myopia presents itself, the worse it will be. “It’s difficult because you don’t see immediate effects,” says Polling. “You need a lot of exposure from a very young age and then, at the age of eight, you finally become myopic.”
Some parents with mild myopia aren’t too concerned if their child is diagnosed with a similar prescription, he says. But if you’re -3D at 8 you are basically certain to be -6D or above at 18. And the macular degeneration might arrive in your 40s or 50s. “These windows are precious and fleeting,” says Polling. “If we can delay the onset of myopia until 12 instead of 10, that’s a huge difference.”
What’s interesting – okay, what’s maddening – is that when you bring this sort of thing up with parents, they will often treat screens as a symptom of myopia as opposed to a cause. As in: “Oh yes I’ve noticed that Rosa always holds the phone up close to her face when she’s watching cartoons in bed.”
Here is an account from an online myopia community from a parent panicking about the results of their 3-year-old’s first eye examination: “He would watch TV up close (but most kids seem to) but also watch the phone up close with his head tilted to one eye …” It’s almost as if we accept it as inevitable. A bit of genetic bad luck. As opposed to something we might actually do something about.
The difficulty for ophthalmologists comes with framing a condition that will be perfectly manageable for most people and may not present any complications as a matter of urgency until decades down the line. The costs involved might focus minds: 60 years of a £15 a month contact lens prescription is £10,800.
As might the risks. A few years ago, I contracted acute keratitis from dirty contact lenses. This is an infection of the cornea that can lead to blindness – and honestly, the pain was unbelievable. It was like having sandpaper and chilli alternately rubbed into my right eye and the cure was almost as torturous. I had to apply eye drops every 30 minutes for 48 hours. I have been scrupulous about contact lens hygiene ever since.
But that’s the thing about eyes. You take them for granted until you don’t. “I speak to people who have macular degeneration in their 40s and 50s,” says Dahlmann-Noor. “They are incredibly bitter. They say: ‘I just wish someone had warned me that this was on the cards.’” It’s certainly enough to be a serious long-term worry for the NHS.
Still, Dahlmann-Noor expresses some optimism. “For all my life, there was nothing you could do about the growth of the eyeball. You’d go and have your eyes measured, you’d get your new glasses, and that was it. But now myopia has become such a problem that there has been a lot of research and there are finally treatments.”
It is not possible to stop or reverse the onset of myopia. But it is possible to slow it down. Corrective glasses and contact lenses work by creating a second image shell in front of the retina, which pulls the image forward and counteracts the elongation of the eyeball. These have been shown to slow the progression of myopia by 40-50%.
Then there are atropine eye drops, which are already widely prescribed in Asia (sometimes to pre-myopic infants) and are likely to become available in the UK this year. However, neither of these remedies will be immediately available on the NHS – and the costs of corrective lenses are often prohibitive.
There are factors that are beyond the control of medics. “These Big Tech companies need to start taking care of kids’ health,” says Polling. “They need to make their apps less addictive. And to warn parents not to give children phones before the age of 6 and keep them to a minimum after that.”
Given the extreme indifference tech companies have so far displayed towards the welfare of children, you’d have to say they are extremely unlikely to do that without being legally obliged to do so. “Now, I’m sorry, that’s not very optimistic!” he laughs. “But there is something children can do,” he stresses. “Just play outdoors.”
