Researchers think that our vision is deteriorating because we are not home enough.
Myopia is more common than ever, and if the trend continues, in 2050 one in two people will be myopic.
This is the conclusion reached by a research team supported by the Brien Holden Vision Institute after an analysis of global data.
The scientists compared data from 145 smaller myopia studies in a total of 2.1 million subjects.
They found that the number of myopia worldwide has increased from around 1.5 billion in 2000 to 2 billion now.
If the number of nearsighted people continues to rise according to the scientists' prediction, there will be 4.75 billion nearsighted by 2050 - probably half the world's population at that time.
Go out more
We may have to find the explanation in our modern lifestyle, where we mainly stay indoors.
The researchers cannot demonstrate a direct link between computer work and myopia, but they can prove that a two-hour stay in the open air significantly reduces the risk of developing myopia.
They explain that it is not certain what exactly causes the positive effect of a stay outside the home. It is possible that we look further outside, or that the sunlight generates a favorable chemical reaction in the eye.
Two hours is enough
The positive effect, however, is beyond dispute, they swear.
"... It is generally accepted that it has a protective effect to spend at least two hours a day outside," Kovin Naidoo tells the Huffington Post.
If you spend only two hours a day outside, it doesn't really matter what you do the rest of the day. The negative effect of an office job or study where you have to read a lot is therefore compensated by two hours in the open air.
This also explains why myopia is very common among Asian children, who often study all day long and are not encouraged to play outside.
In many Asian countries, more than 80 percent of young adults are now myopic.