So I just had Lasik on my eyes so I have been thinking about my nearsightedness a lot lately. My vision prior to surgery was horrible (in the 20/200 range, or 7.5 diopters in my right eye and 5.5 in my left). I couldn’t even see the big E on the chart. And as I have talked to people it is clear I am far from alone. Countless people who I know have equally bad if not worse vision. This started me thinking, how could I or any of them ever have survived in the caveman and cavewoman days? (and I would like to point out that spell checker accepted caveman as OK but does not recognize cavewoman. A bit sexist I would say. Cavewoman power!). There is no way with my old vision I could have hunted or even foraged effectively. My spears would never have hit their targets and I would likely have been picking up rocks and rabbit droppings thinking they were berries. So clearly this must be increasing due to environmental reasons. And indeed studies show that rates of myopia (near sightedness) are on the rise.
The reason for this seems obvious to me. In the last thousand years and much more so in the last 100 years we have started spending more and more time indoors. We are now at a point where by far the majority of our life is spent indoors. It is great being in climate control and out of the elements but our eyes rarely have to fix on anything more than 30 feet away. And they can’t look much further than that because there is likely a wall in the way. I have learned through my research into the human body how amazingly adaptive it is. So it seems like our brain and our eyes have adjusted to live at 30 feet or less. Adapt to looking at things up close at the expense of looking at things far away which rarely happens. And this would explain why in most people vision is normal at birth and early childhood and it is not until elementary school or later that glasses are needed.
Indeed a study was done in 2008 in the journal Opthamology by faculty at the University of Sydney, Australia that showed that higher levels of time spent outside by children decreased the risk for nearsightedness. And it did not seem that exercise seemed to make a difference, just time outside.
This I think leads to a much-needed study. We have to quantify how much time needs to be spent outside to hopefully eliminate the risk for nearsightedness. We already have so many reasons to turn off the TV and gets kids outside, but it might be even more convincing to have a recommendation for X number of hours outside to keep vision strong and avoid the need for glasses. No surgery, no drugs, just playing outside.