An international portrait of myopia

The discussion was part of a series of webinars organised by the Singapore National Eye Centre entitled Myopia dialogues.

This session was moderated by Associate Professor Audrey Chia and Dr Loh Kai Lyn from the Myopia Centre, Singapore National Eye Centre.

Chia shared that a common fear is that the myopia epidemic that began in the 1980s in countries like Taiwan, Singapore, Hong Kong and South Korea could spread worldwide. In 2016, Brien Holden et al predicted that 50% of the world's population would be short-sighted by 2050.

Among a number of topics – including levels of myopia in the panellists’ home countries and the knock-on effects on secondary care – the panellists considered whether Holden’s prediction would come true. Below OT provides a summary of the discussion.

From low to rising myopia in India

Professor Rohit Saxena of the All India Institute of Medical Sciences in New Delhi said the proportion of myopic children in India has increased over the last decade.

“Especially after COVID, we are seeing a very significant increase,” he said.

Saxena shared that with the increasing educational level of the population and the increasing use of digital devices, the time spent on close work has also increased significantly.

In a semi-urban area near Delhi, the myopia rate increased from 7% in 2001 to 13% in 2013.

“A recent evaluation in the same area now shows a prevalence of about 21%,” he said.

All panelists were asked to reflect on a prediction from a 2016 study by Brien Holden. et al that by 2050, half of the world's population could be short-sighted.

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

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

“It is possible that we can reach 50%, and if that is true for India, then I believe it will soon be true for the whole world,” he said.

A burden on secondary care in China and Taiwan

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

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

The head of the research center said that myopic maculopathy has overtaken cataracts as the leading cause of blindness in adults in the central Shanghai area.

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

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

He noted that in Taiwan, as in many countries where myopia increases at an early age, over 80 percent of young and middle-aged adults are nearsighted and about 20 percent suffer from severe myopia.

This has led to an increase in complications related to myopia. Wu stressed that myopic maculopathy is now the leading cause of blindness in the elderly.

“The disease burden in Taiwan is very high. There are many patients with retinal detachments in the emergency room,” he reported.

Wu stressed that the rate of retinal detachment among people in their twenties in Taiwan is ten times higher than among people in their twenties in the Netherlands.

A note on Europe

Professor Andrzej Grzybowski of the University of Warmia and Mazury in Poland explained that although there has been an increase in myopia cases in Europe, the pattern is inconsistent.

“There is considerable evidence that myopia has increased significantly in Southeast Asia over the past few decades,” he said.

“We have also seen an increase in myopia in Europe and North America, but the dynamics there are not as strong,” says Grzybowski.

We need to focus our efforts on getting preschool and elementary school children out into the outdoors.

The lack of a standard definition of myopia and studies using non-cycloplegic refraction limit the epidemiological evidence available in Europe.

Grzybowski also expressed his view on Holden's prediction that half the world's population will be nearsighted by 2050.

“I think that may be true in some parts of the world, but probably not the whole world. I don't think Europe is following the same pattern of development and spread as Asia,” he said.

Nature vs. 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 found that the Sydney Myopia Study found lower rates of myopia among children of Japanese, Chinese, Singaporean and Korean descent living in Sydney than among children living in Japan, China, Singapore and Korea.

However, the rate of myopia in this group of Australian children was still higher than in European-Caucasian children in Sydney.

“Parents bring their lifestyle with them, and we see that clearly in children’s behavior toward school and the pressure parents put on those children to attend additional academic classes outside of school hours,” Rose says.

Professor Ian Morgan of the Australian National University said that data on cycloplegia for myopia in young adults in Europe showed that only about 20 to 30% of them were short-sighted.

“I think the only part of the world where the [Brien Holden et al] The forecast applies to East Asia,” he said.

Public health messages

Morgan emphasized that research suggests that spending time outdoors protects against the development of myopia.

In his view, the public health message should be made clear and a case should be made for integrating outdoor teaching into the school day.

“The key is to find a balance between the amount of close work children do and the amount of time they spend outdoors,” Morgan said.

“Once their working hours exceed the time they spend outdoors, myopia sets in. The greater this imbalance becomes, the more likely they are to be nearsighted,” he said.

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

“Everyone you know blames digital devices just because they see kids holding them, but they're probably not the direct cause. They could be a new form of close-up work for kids and deter them from going outside,” he said.

He added that it is important not to overlook the role of parental shortsightedness.

“I think short-sighted parents should be encouraged to get their children tested early, and they should also be encouraged to go outside with their children,” he said.

Morgan stressed the importance of taking early action to prevent myopia.

“We need to focus our efforts on getting preschool and elementary school-aged children outdoors. I believe that is the best way forward from a public health perspective,” he said.

Indoor-centric lifestyle in Singapore

Professor Saw Seang Mei of the Singapore Eye Research Institute explained that many children in Singapore have an “internally centered” lifestyle – a factor that likely contributes to the country’s high rate of myopia.

“The challenge was to encourage children to spend more time outdoors,” Saw stressed.

A recent study tested the light intensity to which a child doll was exposed in different environments. The study found that the light intensity outdoors, both with and without sun protection, was 100 times higher than indoors.

Saw said that even under a tree with a hat and sunglasses, the light intensity is sufficient to provide protection.

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

“You just need to be outside – in the shade and with sun protection if necessary,” Saw added.

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