Ok I get we all look at small letters and images on screens and paper these days. Is this why in the last 150 years or so millions and millions of humans need spectacles? Is it because we are meant to be looking at things from a distance rather than nearby so our eyes haven’t caught up?
In: Biology
It’s reading and it’s living indoors
Being inside and reading cause nearsightedness.
This is why glasses are basically universal in East Asia
There’s a fair amount of evidence that bright light during infancy and childhood reduces the possibility of myopia (near sightedness), so the fact we have gone from living outdoors on the plains of Africa to living mostly indoors may have some effect, but it’s still not clear how large of an effect this actually is
I’m legally blind. I wouldn’t be able to leave my house or even watch TV or read books without my glasses. I need to hold objects mere inches from my face to see it clearly.
I would of been eaten by a bear or something 500 years ago lol
I don’t have any scientific evidence lined up to back this, but I strongly suspect our modern society is the main cause of poor eyesight. Spending multiple hours per day focused on a screen or other object relatively close to your face (most likely) weakens your eyesight. Back in the day, people who spent all day reading or writing books needed glasses but the average population didn’t.
Besides all the answers about what *causes* more nearsightedness, there’s also no more evolutionary selection against it. Assume it was very genetic, the ancient people which needed glasses just died much sooner because of all kinds of dangers, and then have fewer nearsighted children.
Today, a kid with glasses has the same survival chances as one without. At least in a developed country.
I am very nearsighted. I grew up learning how to identify people by body shape and how they moved. Their have also been studies showing nearsighted people see movement better. I wear glasses constantly but I can and do go without them when I have a headache or just want to lay in bed.
It turns out that childhood exposure to sunshine is critical for the development of our vision. Kids need to be outside to prevent myopia; the artificial light we currently use just doesn’t cut it: too dim and not enough of the right frequencies of light.
The switch to universal schooling meant that kids were spending large parts of the daytime under roofs and artificial light. The recent change to helicopter parenting and kids addicted to screens mean that they are spending even less time outside. (In my youth, we put blame on reading too many books, but it turns out that the problem was too much time inside reading.)
Myopia was less of a problem for our ancestors because they spent their entire lives outside under the sun.
https://www.canr.msu.edu/news/the_benefit_of_daylight_for_our_eyesight
The latest research shows the need for glasses is strongly linked to lack of periodic exposure to bright sunlight and UV, particularly during the developing years. It has nothing to do with watching TV or computer screens.
As to how we got by in the past: Basically you didn’t. I just read diaries from the original south pole expeditions: those who couldn’t see long distance basically were excluded from becoming navigators and had to be put under the care of a navigator, and those who couldn’t see short distance were basically excluded from book-work/reading/writing etc. You see the same thing in writings of the Romans. Eye tests were mandatory for a lot of positions.
Our ancestors very rarely got back pain because they didn’t sit for 10+ hours a day.
Our ancestors had healthier teeth without brushing because their food was fibrous and required 10x more chewing.
Our ancestors didn’t need glasses when they lived outside and didn’t stare at books/screens for hours straight.
Reading glasses were invented in 1286 in Italy.
So many people in this thread are assuming rates of poor vision are the same now as they were in the past.
This is NOT true.
For example, 41.6% of Americans were nearsighted in 2004. 25 percent of Americans were nearsighted in 1971. That’s a 66% increase in ~30 years.
Our ancestors from the 1800s and prior had, on average, much better vision than we do today.
Scientists are still working out the causes, but there seems to be a positive association between educational attainment and poor vision. One other theory I see mentioned is reduced exposure to natural sunlight in childhood – children who spend more time outdoors have a lower chance of becoming nearsighted.
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