- Have you ever had a discussion at work where people were talking about their vision?
“I’m a minus two.”
“Oh that’s not too bad. I’m a minus five. I’m practically blind, haha.”
Then the whole group usually chimes in describing their particular visual defect. In fact, it’s almost rare to find someone that doesn’t have a problem with their eyesight.
When you stop to think about it for a second, isn’t that odd? Strong eyesight, believed to give primates the ability to detect snakes, among other things, is a hallmark of the human species. And yet, it seems that many people have trouble seeing as they should. In fact, almost 75% of the US population wears some kind of corrective lens, up from 57% in 2001.
What’s going on here?
We’re Getting Older
Scientists have a few theories for why vision problems seem to be getting worse among the population. For one, we are getting older and our vision deteriorates as we age.
Natural Selection for Eyesight Is No Longer Needed (Maybe)
Another theory suggests that strong vision is no longer important to our survival because we can correct the problem with glasses. Therefore, evolutionary pressures no longer weed out visual defects from the gene pool.
Other researchers have discredited this theory, however, arguing that the growth rate of people with vision problems far outpaces the speed at which we typically observe such evolutionary changes in humans.
Time Spent Indoors Harms Vision
To me, at least, the most convincing argument seems to be that, besides genetics, the human eye needs natural light in childhood to develop properly. As more people live in cities and stay indoors, they don’t get enough sunlight to foster strong vision.
A study that compared ethnically-Chinese children in Singapore and Australia found that only 3.3% of Australian children developed near-sightedness compared to 29% of the group from Singapore, despite the parents of both groups exhibiting about the same proportion of near-sightedness. Between both groups, the researchers found that time spent outdoors was the largest factor in predicting whether a child would eventually develop vision problems. The children from Australia spent over four times more time outdoors per week compared to the children from Singapore.
More research has been supporting this theory, suggesting that our change in lifestyle as a species may be contributing to our vision problems.
Why Do So Many People Need Braces?
And our vision isn’t the only place where modern environmental conditions may be negatively affecting our development. Between 50%-70% of children in the US get braces nowadays, but poorly aligned teeth weren’t a problem for our ancient hunter-gatherer ancestors. In fact, most skulls of hunter gatherers in museums have jaw structures that would make Hollywood stars jealous!
The problem seems to stem from ancient dietary changes and technological innovations. As our ancient ancestors settled down and began to cook more frequently, their jaws no longer needed to work as hard to chew the soft, cut-up food we’ve come to enjoy today. Unfortunately for us, (but perhaps fortunately for our orthodontists) our jaws evolved to rely on chewing tough food to grow properly. Without it, our jaw and facial structures may never reach their proper size causing our teeth to become misaligned.
And the problem has only been getting worse over time. Another study found that medieval peasants in Norway had poor alignment in their teeth 36% of the time compared to 65% of modern Norweigans located in the same graveyard.
Trouble Adapting to the Modern World
Besides problems with our vision and teeth, the rise of other alignments, such as depression, anxiety, obesity, and autoimmune diseases have all been linked, in part, to the radical environmental changes that have come along with modern life. Luckily, modern life also produces scientific knowledge that helps us counteract some of these problems–but the rise of these issues should emphasize the importance of going outside, eating right, and getting plenty of exercise. Our bodies rely on it!
