Optometry researchers estimate that about half of the global population will need corrective lenses to offset myopia by 2050 if current rates continue – up from 23% in 2000 and less than 10% in some countries.
The associated health care costs are huge. In the United States alone, spending on corrective lenses, eye tests, and related expenses may be as high as US$7.2 billion a year.
What explains the rapid growth in myopia?
I’m a vision scientist who has studied visual perception and perceptual defects. To answer that question, first, let’s examine what causes myopia – and what reduces it.
How myopia develops
While having two myopic parents does mean you’re more likely to be nearsighted, there’s no single myopia gene. That means the causes of myopia are more behavioral than genetic.
Optometrists have learned a great deal about the progression of myopia by studying visual development in infant chickens. They do so by putting little helmets on baby chickens. Lenses on the face of the helmet cover the chicks’ eyes and are adjusted to affect how much they see.
Just like in humans, if visual input is distorted, a chick’s eyes grow too large, resulting in myopia. And it’s progressive. Blur leads to eye growth, which causes more blur, which makes the eye grow even larger, and so on.
Two recent studies featuring extensive surveys of children and their parents provide strong support for the idea that an important driver of the uptick in myopia is that people are spending more time focusing on objects immediately in front of our eyes, whether a screen, a book or a drawing pad. The more time we spend focusing on something within arm’s length of our faces, dubbed “near work,” the greater the odds of having myopia.
🌟🌟GP🌟🌟 Let’s dive into history and find it. Throughout history, countless women worldwide have made significant contributions to society, breaking barriers and paving the way for future generations. In this blog post, I am trying to honour a few of these extraordinary women and their enduring legacies. 1. Marie Curie: The Pioneer of Radioactivity “Marie […]
In 1956, my uncle John F. Kennedy, then a U.S. senator, wrote a book that is probably more famous for its great title than its contents. It was called Profiles in Courage. And it was about eight U.S. senators who JFK felt had made particularly courageous contributions to American history.
For a while now, I have been thinking about what courage means to me. While growing up with my father, Ted Kennedy, in the Senate, and then serving in the House of Representatives myself for many years, I saw quite a bit of bravery in politics. But the truth is, the most courageous people I know qualify not for what they do in public, but what they are able to endure and rise above in private. This is especially true of people who struggle every day with mental illness, or addiction, or both, or who help loved ones or family members in their struggles.
The details and daily dramas of these struggles usually remain private, hidden. And even when people discuss them publicly, it’s often in a brief or very cautious way—enough to admit to having a diagnosis or a problem, or “issues,” in order to support advocacy, but rarely enough to inform a public that wants and needs to understand what living with these illnesses is like every day. When I was younger, and first outed for substance use disorder treatment in the tabloids by someone I was in rehab with, I thought this was all harder for people in the public eye. But I have since learned better: we all live with the same stigma, and pay the same price for our silence.
We often quote the statistic that, at any given time, at least a quarter of all Americans struggle with mental illness, substance use disorder, or both. And while these are still sometimes viewed as two separate illnesses—because two distinct worlds developed to address them—I can tell you as someone who has them both that they are best understood and treated together as one complex continuum of diseases of the brain and mind.
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Then Senator John F. Kennedy autographs a copy of his book ‘Profiles in Courage’ for a group of young men and women. Corbis—Getty Images
The strongest force in the universe is called, aptly, the strong force. We never get to witness its fearsome power because it works only across subatomic distances, where it binds quarks together inside protons and neutrons and joins those nucleons into atomic nuclei. Of the four basic forces of nature, the strong force is by far the most potent—it’s 100 trillion trillion trillion times stronger than the force of gravity. It’s also the most mysterious.
Despite knowing roughly how it compares with the other forces, scientists don’t know precisely how strong the strong force is. The other three forces—gravity, the electromagnetic force, and the weak nuclear force (responsible for some radioactivity)—are much better measured. The strength of electromagnetism, for example, denoted by its “coupling constant,” has been measured with the same precision as the distance between New York and Los Angeles, to within a few hair breadths. Yet the strong force’s coupling constant, called αs (“alpha s”), is by far the least understood of these quantities. The precision of the best measurements of αs is 100 million times worse than that of the electromagnetic measurement.
Even this level of (un)certainty is known only in the simplest domain of the strong force theory, at very high energies involved only in some of the rarest and most extreme events in nature. At the lower energies relevant to the world around us, the strong force earns its name by becoming truly intense, and concrete information on αs in this range is scarce. Until recently, no one had made any experimental measurements of αs at this scale. Theoretical predictions for its value were unhelpful, covering the entire span from zero to infinity.
The strong force’s might makes it difficult to study in lots of ways. The theory describing how it works, called quantum chromodynamics, is so complicated we can’t use it to make direct calculations or precise predictions. One of the reasons for this complexity is that the carrier of the strong force—a particle called the gluon—interacts with itself. Electromagnetism, in comparison, is simple because its carrier, the photon, is chargeless. But the gluon carries the strong force’s version of charge, called color, and its self-interactions quickly get out of hand. So despite its importance to nuclear physics and building the material world, the strong force is not unconditionally loved by researchers. Instead many look at the domain where the strong force is truly strong as a “Terra Damnata,” a realm to avoid at all costs.
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In October 2022 a bird with the code name B6 set a new world record that few people outside the field of ornithology noticed. Over the course of 11 days, B6, a young Bar-tailed Godwit, flew from its hatching ground in Alaska to its wintering ground in Tasmania, covering 8,425 miles without taking a single break. For comparison, there is only one commercial aircraft that can fly that far nonstop, a Boeing 777 with a 213-foot wingspan and one of the most powerful jet engines in the world. During its journey, B6—an animal that could perch comfortably on your shoulder—did not land, did not eat, did not drink, and did not stop flapping, sustaining an average ground speed of 30 miles per hour 24 hours a day as it winged its way to the other end of the world.
Many factors contributed to this astonishing feat of athleticism—muscle power, a high metabolic rate, and a physiological tolerance for elevated cortisol levels, among other things. B6’s odyssey is also a triumph of the remarkable mechanical properties of some of the most easily recognized yet enigmatic structures in the biological world: feathers. Feathers kept B6 warm overnight while it flew above the Pacific Ocean. Feathers repelled rain along the way. Feathers formed the flight surfaces of the wings that kept B6 aloft and drove the bird forward for nearly 250 hours without failing.
One might expect that considering all the time humans have spent admiring, using, and studying feathers, we would know all their tricks by now. Yet insights into these marvelous structures continue to emerge. Over the past decade, other researchers and I have been taking a fresh look at feathers. Collectively we have made surprising new discoveries about almost every aspect of their biology, from their evolutionary origins to their growth, development, and aerodynamics.
Among the creatures we share the planet with today, only birds have feathers. It makes sense, then, that for centuries scientists considered feathers a unique feature of birds. But starting in the 1990s, a series of bombshell fossil finds established that feathers were widespread among several lineages of the bipedal, carnivorous dinosaurs known as theropods and that birds had inherited these structures from their theropod ancestors. The discovery of feathered nonbird dinosaurs sent researchers scrambling to understand the origin and evolution of feathers, especially their role in the dawn of flight. We now know many dinosaurs had feathers, and protofeathers probably go all the way back to the common ancestor of dinosaurs and their flying reptile cousins, the pterosaurs. Bristles, fuzzy coverings, and other relatively simple featherlike structures probably decorated a wide array of dinosaurs—many more than we have been lucky enough to find preserved as fossils.
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Bar-tailed Godwits undertake the longest nonstop migration of any land bird in the world. rockptarmigan/Getty Images
Film and Writing Festival for Comedy. Showcasing best of comedy short films at the FEEDBACK Film Festival. Plus, showcasing best of comedy novels, short stories, poems, screenplays (TV, short, feature) at the festival performed by professional actors.
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Bar-tailed Godwits undertake the longest nonstop migration of any land bird in the world. rockptarmigan/Getty Images
James' World 2 