It isn’t just my imagination, and it isn’t just in any one nation. Nearsightedness impacts around every second person in the US and Europe, up from half that 50 years ago. If you think that’s shocking, it is more pronounced in Asia, for instance in China where 10-20% were shortsighted in 1960 compared to 90% today. The numbers in Seoul are even more shocking: 96.5% of 19 year old men were shortsighted in a 2012 study.
Although twin studies have shown that genetics plays a role in nearsightedness, genetic changes could not happen fast enough to explain these dramatic increases occurring within only a few generations. Instead, environmental and lifestyle factors must be “pushing” people so far in the direction of nearsightedness that not only those with a strong genetic predisposition are becoming nearsighted.
So what’s going on? Is this informational poster from Singapore onto something?
Well, yes and no. Yes, going outside more and using fewer handheld devices can help, but playing at the playground might not necessarily help. A study published in 2007, looking at 514 children with healthy vision in 1989, until 2001, found that hours spent reading or on the computer were themselves not significant to the development of shortsightedness (myopia), but time spent doing activities outside was. Further studies looking at the role of physical activity levels found that it was being outside, not moving around, that mattered.
Experiments with rhesus monkeys found that reducing the light levels the monkeys experience to “indoor” light levels (which are over 10x less than outside) significantly increased the levels of shortsightedness (myopia). It is the shift towards city and indoor life that is fueling the dramatic increase in shortsightedness. It was the presence of real sunlight, objects at varying distances, and the quick refocusing of the eye to different distances, that likely staves off a shift towards nearsightedness.
Is it possible to fix nearsightedness, once the body has adjusted to a life of close objects? Well, so far laser surgery has offered the highest chances of success, although it appears no one has experimented with attempts to retrain the eye. Despite the fact that this seems unlikely, I certainly won’t say its impossible, and if you want to try it out then there is certainly no risk (just don’t drive, obviously). For all of us who don’t need glasses: we should thank our luck and continue to get outside and look out into the distance.