Why is myopia increasing?
I have worn eyeglasses since the second grade. I not only suffer from myopia in one eye, I have a severe astigmatism in the other. The stigmatism means that contact lenses have never been an option for me, and thus I've had a lifelong experience with eyeglass technology. My first set of glasses had lenses of actual glass. I can still remember the revelation that my first pair of polymer lenses were. So light… and so easily scratched.
Myopia in my case is genetic, my mother's glasses were thick enough to be compared to thickness of the bottoms of the old glass Coke bottles (and yes that reference likely gives an idea of how old the writer is.) The state of myopia is in flux it would seem. Myopia rates in Asia have been skyrocketing for years. The standard reason proffered typically is the vast amount of reading and schoolwork that Asian school children do. Incident rates of myopia is rising in the US and Europe as well, with roughly 50% of children becoming myopic. This increased incidence cannot be explained with genetics.
More myopia, more eyeglasses
Rates of myopia interest LWRAS because a significant percentage of eyeglass lenses are coated with optical coatings, and the optical coatings market has been of internet for almost two decades (note: The optical Coatings reports were written for BCC Research, and thus that analysis cannot be presented on this site.) Rates of myopia in Asia have been greater than the rest of the world for a number of years. The standard reasoning for this discrepancy was that Asian school kids do much more homework than students elsewhere.
East Asia has been gripped by an unprecedented rise in myopia, also known as short-sightedness. Sixty years ago, 10–20% of the Chinese population was short-sighted. Today, up to 90% of teenagers and young adults are. In Seoul, a whopping 96.5% of 19-year-old men are short-sighted.
However, roughly 50% of youth in US and Europe are also affected with myopia. They used to think it was reading too many books, now they are thinking that it’s too much time indoors. Genetics can play a role too. But in populations whose lifestyle changed and became more indoors, eyesight deteriorated, and that’s not genes. The idea reading harms the eyes is old, Johannes Kepler blamed reading for his poor eyes.
It was a study of kids in California that found the ASSOCIATION of outdoor time and eye health. An Australian study found the same association. However, not everyone is on board with the idea that its time indoors. To offset the effect, it wasn’t necessary to play or do sports either. You just needed to be outside— or maybe you just needed to have natural light? It might light INTENSITY, not being outside that matters. It’s a good argument for windows and skylights.
Based on epidemiological studies, Ian Morgan, a myopia researcher at the Australian National University in Canberra, estimates that children need to spend around three hours per day under light levels of at least 10,000 lux to be protected against myopia. This is about the level experienced by someone under a shady tree, wearing sunglasses, on a bright summer day. (An overcast day can provide less than 10,000 lux and a well-lit office or classroom is usually no more than 500 lux.) Three or more hours of daily outdoor time is already the norm for children in Morgan's native Australia, where only around 30% of 17-year-olds are myopic. But in many parts of the world — including the United States, Europe and East Asia — children are often outside for only one or two hours.
So it’s not more time outside (though that’s a fine recommendation) it’s brighter lighting that’s needed and/or MORE WINDOWS. Basically after some quick research (for instance here) it seems that you want to be as near to the window as possible, and depending on the direction of the sun you can get up to 5000 lux. 1000 lux is probably more typical, and it’s nothing like what you can get from going outside, even if you stick to the shade. The numbers here are a bit different. Here’s a very expensive solution (that uses coatings).