An international portrait of myopia

The discussion was part of a series of webinars organised by the Singapore National Eye Centre and titled Myopia Dialogues.

This session was moderated by associate professor Audrey Chia and Dr Loh Kai Lyn from the Singapore National Eye Centre’s Myopia Centre.

Chia shared that a common fear is that the myopia epidemic, which started in countries such as Taiwan, Singapore, Hong Kong and South Korea in the 1980s, will start to spread worldwide. In 2016, Brien Holden et al predicted that 50% of the world’s population would become myopic by the year 2050.

Among a range of topics – including myopia levels in panellists’ own nations and the flow on effects for secondary care – panellists addressed the question of whether Holden’s prediction would come to fruition. Below OT presents a summary of the discussion.

From low to growing levels of myopia in India

Professor Rohit Saxena, of the All India Institute of Medical Sciences in New Delhi, shared that over the past decade there has been an increase in the proportion of children with myopia in India.

“Particularly post-COVID, we are seeing a very significant rise,” he said.

Saxena shared that as populations have become more educated, and digital device use has increased, there has been a rapid growth in time spent on near work.

In one semi-urban area near Delhi myopia rates rose from 7% in 2001 to 13% in 2013.

“A recent evaluation in that same area now shows a prevalence of around 21%” he said.

All panellists were asked to reflect on a prediction from a 2016 study by Brien Holden et al that half of the world’s population could be myopic by 2050.

Saxena shared that a decade ago he would not have thought that half of India’s population would be myopic by 2050.

However, the Indian population is now experiencing an “exponential increase” in myopia levels – including in rural areas, where around 60% of children live.

“It’s possible that we might hit 50% and if that’s true for India – I think it would really start being true for the entire world,” he said.

A burden on secondary care in China and Taiwan

Dr Xiangui He, of the Shanghai Eye Disease Prevention and Treatment Center, shared that myopia levels began to rise in China in the 1980s.

“Over the past 40 years, the myopia rate among high school graduates has risen rapidly and has now reached around 80%” she said.

The research centre director shared that myopic maculopathy has surpassed cataracts as the leading cause of adult blindness in the central urban area of Shanghai.

Myopia in focus

The AOP and OT have partnered with CooperVision to explore issues surrounding myopia through our Myopia guide series. Read more online.

“Our team found that the overall prevalence of myopic maculopathy among people over 50 years old with high myopia is as high as 66%” she said.

Professor Wu Pei Chang, of the Kaohsiung Chang Gung Memorial Hospital, shared that the prevalence of myopia in Taiwan is “very high.”

He observed that in Taiwan, as in many countries with an early influx of myopia levels, more than 80% of young adults and those entering middle age are myopic, with around 20% experiencing high myopia.

This has translated into a growth in complications associated with myopia. Wu highlighted that myopic maculopathy is now the most common cause of blindness in older people.

“The burden of pathology is very heavy in Taiwan. There are many patients with retinal detachments in the emergency room,” he shared.

Wu highlighted that the rate of retinal detachments among people in their 20s in Taiwan is 10 times higher than among people in their 20s in the Netherlands.

A note on Europe

Professor Andrzej Grzybowski, from the University of Warmia and Mazury in Poland, outlined that while there has been an increase in myopia rates within Europe, the pattern has been mixed.

“There is a huge accumulation of evidence that the prevalence of myopia in Southeast Asia increased significantly in the recent decades,” he said,

“Regarding Europe and North America, we have also noticed an increase in myopia but it does not follow the same dynamic,” Grzybowski shared.

We've got to concentrate our efforts in getting kids outdoors in the pre-schools and the early primary school years

A lack of a standard definition of myopia and studies that use non-cycloplegic refraction have limited the epidemiological evidence available within Europe.

Grzybowski also shared his view on the Holden prediction that half of the world’s population will be myopic by 2050.

“I think that it might be accurate for some parts of the world, but probably not for the whole world. I don’t think Europe will follow the same pattern of development and prevalence as we see in Asia,” he said.

Nature v nurture

Professor Kathryn Rose, of the University of Technology Sydney, highlighted evidence supporting the view that lifestyle plays a more significant role in the development of myopia than genetics.

She noted that the Sydney myopia study found lower rates of myopia among children of Japanese, Chinese, Singaporean and Korean origin who were living in Sydney, than among children living in Japan, China, Singapore and Korea.

However, this group of Australian children still had higher rates of myopia than European Caucasian children living in Sydney.

“Parents do bring their lifestyle with them, and we certainly see it in the behaviour of the children around schooling and parental pressure on those children to do additional academic classes outside school time,” Rose shared.

Professor Ian Morgan, of the Australian National University, shared that cycloplegic data on myopia levels among young adults in Europe found only around 20–30% had myopia.

“I think the only part of the world which the [Brien Holden et al] projection holds for is east Asia,” he said.

Public health messages

Morgan stressed that the research suggests outdoor time protects against the development of myopia.

He believes that there should be a strong public health message encouraging outdoor time to be included within schooling environments.

“What is crucially important is the balance that children have between the amount of near work they are doing and the time spent outdoors,” Morgan said.

“Once their near work hours start to exceed their hours of time outdoors, that’s when they start to develop myopia. The more that imbalance grows, the more likely they are to be myopic,” he said.

Morgan noted that while digital device use may play a role in the development of myopia, it is unlikely that this is intrinsic to this technology.

“Everybody you know is blaming digital devices just because they see children holding them, but they're probably not a direct cause. They may well be a new form of near work for children, and equally an inhibitor for going outdoors,” he said.

He added that it was important not to overlook the role of parental myopia.

“I think parents who are myopic should be encouraged to have their children tested young, and they should also be encouraged to get their child outside,” he said.

Morgan emphasised the importance of acting early to prevent myopia.

“We've got to concentrate our efforts in getting kids outdoors in the pre-schools and the early primary school years, and I think that's the best way to move forward in terms of a public health approach,” he said.

Indoor-centric lifestyles in Singapore

Professor Saw Seang Mei, of the Singapore Eye Research Institute, shared that many children in Singapore have “indoor-centric” lifestyles – a factor that is likely to be driving high myopia rates in the nation.

“The challenge has been to encourage children to spend more time outdoors,” Saw highlighted.

Recent research tested the light levels that a child-sized mannequin was exposed to across different settings. The study found that light levels outdoors, both with and without sun protection, were 100 times greater than indoor light.

Saw shared that even under a tree with a hat and sunglasses on, the light levels were sufficient to have a protective effect.

“The good news is that your child doesn’t have to be baking in the sun,” she said.

“They just need to be outdoors – in the shade and with sun-protection if required,” Saw added.

Main image: panellists at the Singapore National Eye Centre’s Myopia Dialogues webinar on 31 July.