Shortsighted Taiwan may have lessons for the world as a preventable disease skyrockets

Up to 90% of young people in Taiwan have myopia but eye experts say the growing global trend can be reversed. In the final days of their eight-week bootcamp, dozens of young Taiwanese conscripts are being tested on an obstacle course. The men in full combat kit are crawling underneath rows of razor wire and through bunkers as controlled explosions blast columns of dirt into the air. Pink and green smoke blooms in a simulated gas attack, requiring the conscripts to quickly don gas masks so they can rush the zone. But it’s here where many of them pause, stopping the assault drill to spend precious seconds removing their glasses so the masks will fit.

The conscripts mostly look to be in their early 20s. Statistics suggest that means anywhere up to 90% of them have some degree of myopia, otherwise known as shortsightedness. Taiwan has one of the world’s highest rates of myopia, alongside most of east Asia and Singapore. As well as the platoons of soldiers in spectacles, there are plenty of other signs. Optometry shops are everywhere – just around Taipei there are more than 40 outlets of Own Days, a chain which tests customers’ eyesight and makes prescription eyewear on-site within an hour. Laser eye surgeons advertise the latest tech, relatively cheaply, to a virtual production line of patients each day. And if you were to visit the front desk of a hospital in Taiwan, instead of pens chained to the counter, you’d probably find a pair of glasses.

“Eye health is the most important sensory organ in our body. Every day we wake up and need to use our eyes,” says Dr Wu Pei-chang, a leading Taiwanese researcher of the subject and director of the Myopia Treatment and Prevention Center at Kaohsiung hospital.

Myopia is a preventable disease in which abnormal elongation of the eyeball causes light to focus in front of the retina instead of on its surface. The distortion level is measured in diopters, and high myopia (when the distortion has progressed past -5.00 diopters) can lead to blindness if left untreated. The most crucial time is childhood, while a child’s eyes are still developing. “Once they onset myopia the progression is very fast,” says Wu.

For decades science said myopia was a genetic condition, but from the 1960s and 70s an explosion in rates in east Asian countries – which were concurrently undergoing massive economic and educational expansion – upended that thinking. By the 1990s rates of myopia in Taiwan, Hong Kong, South Korea and Singapore had risen from about 20% to more than 80%. China, initially delayed by the Cultural Revolution, soon joined them.

Governments studied the phenomenon extensively, but it turned out to be quite simple. Myopia is now known to be linked to excessive “nearwork”, like reading, studying and computer work. And more recent studies have found that increased outdoor time is a crucial protective factor.

That’s why scientists say the rates are so high in east Asia and Singapore, where the cultures heavily emphasise high educational outcomes, with extensive study time favoured by parents over outdoor play. It’s now a problem that is spreading around the world. A study published in September in the British Journal of Ophthalmology found global rates of myopia tripled between 1990 and 2023. By 2050, almost half the world’s population is projected to have it, with corresponding earlier onset, faster progression and greater severity.

Taiwan’s rates are still high but government and social programs have shown measurable success and experts say it is well past its peak. As rates rise in the west, it may have lessons to share. Wu, himself shortsighted, was a young resident when he started to notice an alarming number of his patients and colleagues also had myopia, with many facing serious complications of the disease’s advanced progression. It became his life’s work. In 2004 a paper found that high myopia was the number one cause of irreversible blindness in Taiwan. Lobbied by Wu, who was now on national advisory boards, the government enacted new policies including twice-yearly testing of school students, and improved treatment options. But the rates were still increasing.

“The eyes are developing rapidly [in childhood],” says Prof Ian Morgan, a leading expert in the field, from Australian National University. “The myopia has until around the age of 18 to 20 before it stabilises. So if a kid becomes myopic at the age of six, they still have about 14 years for it to get worse.”.

A few years later, two studies – including one from Australia led by Morgan – offered a lightbulb moment for Taiwan. Both found that the more time kids spent outdoors, the less likely they were to have myopia. Wu ran his own trials, finding similar results. It led to a 2010 government initiative “Tian-tian 120” (120 every day), calling for all children to spend at least two hours outside a day as a “protective factor”.