SPEAKER_06: Amazing, fascinating stories of inventions, ideas and innovations. Yes, this is the podcast about the things that have helped to shape our lives. Podcasts from the BBC World Service are supported by advertising.
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SPEAKER_07: 50 things that made the modern economy with Tim Harford.
SPEAKER_04: You can't afford to be slapdash when you're making a spacecraft. At Lockheed Martin, it used to take a technician two painstaking days to measure 309 locations for certain fasteners on a particular curved panel. But according to Shelley Peterson, the aerospace company's head of emerging technologies, the same job now takes little more than two hours. That changed. The technician started wearing glasses. And not just any old glasses, specifically the Microsoft HoloLens. It looks like a bulky set of safety goggles and it layers digital information over the real world. In this case, it scans the curved panel, makes its calculations and shows the technician exactly where each fastener should go. Productivity experts are gushing about augmented reality devices such as the HoloLens and Google Glass. Many jobs after all involve frequent pauses to consult a screen that tells us what to do next. With smart specs, we can see those instructions while we keep working. It saves a vital few seconds in getting information from internet to brain. A thousand years ago, information travelled rather more slowly. In Cairo, in the 1010s, the Basra-born polymath Hassan ibn al-Haytham wrote his masterwork, the Book of Optics. It took two centuries for his insights to be translated out of Arabic. He understood vision better than anyone before him. Some earlier scholars, for example, had argued that the act of seeing must involve some kind of rays being emitted from the eye. By careful experiment, ibn al-Haytham proved them wrong. Light comes into the eyes. Before ibn al-Haytham, optical devices had been cumbersome. The Roman writer Seneca magnified text using a clear glass bowl of water. But the gradual spread of knowledge inspired new ideas. Sometime in the late 1200s came the world's first pair of reading glasses. Who made them is lost to history, but they probably lived in northern Italy. By 1301, eyeglasses for reading were popular enough to feature in the rulebook of the Guild of Venetian Crystal Workers. But historians' biggest clue to the origin of eyeglasses comes from a sermon in 1306 by Juan Friar Giordano da Pisa. The invention was now 20 years old, he told his congregation in Florence. It was, he enthused, one of the most useful devices in the world. He was right. Reading strained the eyes at the best of times. Medieval buildings weren't famed for their big windows, and artificial light was dim and expensive. As we age, it gets harder to focus on close-up objects. Middle-aged monks and scholars, notaries and merchants, were simply out of luck. Friar Giordano was 50. One could imagine why he appreciated his spectacles so much. But they were useful only to the small minority who could read. When the printing press came along, glasses reached a bigger market. The first specialist spectacle shop opened in Strasbourg in 1466. Manufacturers branched out from concave lenses, which help people to see close up. They learned how to grind convex lenses, which help people focus on things that are far away. Put concave and convex lenses together, and you have the basic ingredients for a microscope or a telescope. Both inventions emerged from the spectacle shops of the Netherlands around the year 1600, opening whole new worlds to scientific study. Nowadays, we take glasses for granted, in the developed world at least. In less developed countries, however, the picture is very different, and only recently did we get a clearer view. Historically, the World Health Organization collected data only on how many people have really serious problems with their vision. Many more can see well enough to muddle through daily life, but would still benefit from spectacles. But how many? The world's leading lens maker, Esselor, decided to find out, no doubt for entirely selfless reasons. In 2012 came the answer. Around the world, two and a half billion people need glasses and don't have them. That's an eye-popping figure, but serious people think it's credible. And many of those 2.5 billion may have no idea that glasses could help them. In 2017, researchers visited a tea plantation in Assam, India. They tested the vision of hundreds of tea pickers aged 40 or over, and gave a simple $10 pair of reading glasses to half of those who needed them. They then compared how much extra tea was picked by those who wore the glasses and those who didn't. Those with glasses averaged about 20% more tea. The older they were, the more their tea picking improved. The tea pickers are paid by how much tea they pick. Before the study, not one owned glasses. By the end, hardly any wanted to give them back. How widely we can extrapolate from this study is hard to say. Picking tea may reward visual acuity more than some other jobs. Still, even conservative estimates put the economic losses from poor eyesight into the hundreds of billions of dollars. And that's before you think about people's quality of life, or children struggling at school. One randomised trial concludes that giving kids glasses could be equivalent to an extra half year of schooling. And the need is growing. Presbyopia, or long-sightedness, comes with age. But among children, there's now a global epidemic of myopia, or short-sightedness. Researchers aren't sure why, though it may have to do with kids spending less time outdoors. What would it take to correct the world's vision? Clearly, more eye doctors would help. The number varies widely from country to country. Greece, for example, has one ophthalmologist for about 5,000 people. In India, it's one per 70,000. In some African countries, it's one per million. But while serious eye problems demand skilled professionals, people whose needs are more easily fixable could be reached by other workers. In Rwanda, a charity trained nurses to do site checks. Researchers found they did them well, over 90% of the time. How about teachers? I've worn glasses since primary school, when my teacher saw me squinting at the blackboard and told my mother to take me to an optician. Another study backs up the idea. After just a couple of hours training, teachers at schools in rural China could identify most children who needed glasses and didn't have them. It shouldn't be rocket science to roll out 13th-century technology. One wonders what Freya Giordano would make of a world in which we build spacecraft in augmented reality but haven't yet helped a couple of billion people fix their fuzzy views of actual reality. He'd probably tell us where to focus.
SPEAKER_07: For more on the origin of glasses, see A History of Reading by Alberto Mengele. For a full list of our sources, please see bbcworldservice.com slash 50things.
SPEAKER_05: Hello, this is Jacqui Leonard from the Global News Podcast. And this week with the UK and you, still in turmoil over Brexit, we're bringing you a very special episode. Over the last couple of years, the BBC's Brexit cast has been one of the most popular podcasts in Britain. It's the political equivalent of going to your local aquarium and pressing
SPEAKER_03: your face up against the glass. And the kind of the political piranhas are just the other side of the screen. It's presented by some of our leading political reporters. It's not
SPEAKER_07: going to happen in a rush. And I would imagine there'll be quite some posturing. But it's
SPEAKER_05: got an irreverent and entertaining tone that has appealed to listeners who are both fascinated and bewildered by Brexit. I was being told by the end of the week, but people have told
SPEAKER_02: me so many things that turn out to not be true. I don't believe anyone anymore. Over
SPEAKER_05: the last few weeks, listeners to the Global News Podcast from around the world have been sending in their Brexit questions. We don't want this, we don't want this and we don't
SPEAKER_06: know what we want. And in our special episode, we will be putting them to the Brexit cast
SPEAKER_05: team. What are they going to say? You guys must know. So for a global perspective on Brexit with answers from people who are living and breathing this stuff at the moment, hop over to the Global News Podcast feed and look for the Global News Brexit cast. Anything
SPEAKER_00: could happen. We know that. Search for Global News Podcast in all the usual poddy places
SPEAKER_05: and you will find the Global News Brexit cast a little way down our feed. I think this is
SPEAKER_03: it.
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