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.

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.