Already earlier, researchers have seen a connection between the amount of time we spend in front of screens and the risk of developing nearsightedness. But the results have varied somewhat, and in some studies, it has been seen that time in front of computers, but not phones, seems to increase the risk.
Now, researchers from, among others, South Korea, have gone through the collected research in the area and seen that screen use overall can be linked to nearsightedness. In total, they have looked at 45 different studies with over 335,000 participants up to 18 years old.
Dose effect
They found that every extra hour spent in front of digital screens per day increases the risk of developing nearsightedness by 21 percent. The largest risk increase was seen between one and four hours of screen time per day. Those who used screens for four hours per day had almost twice as high a risk of developing nearsightedness as those who used screens for one hour per day. After four hours, the risk increase leveled out.
The researchers, who have published their results in Jama Network Open, note that it may be other activities, such as reading books, and genetic factors that also lie behind the risk increase. But since more and more people are becoming nearsighted as various forms of screens take up an increasingly large part of our time, they believe it is likely that there is a connection.
Take seriously
They write that since the use of smartphones globally has increased from 22 percent in 2014 to 69 percent in 2023, the connection may be worth taking seriously.
The advice for avoiding negative effects on vision is to take breaks. The eye needs to exercise focusing on things far away. Even daylight has in investigations been shown to be able to reduce the risk of nearsightedness.
A common tip is the so-called 20-20-20 rule. It means that during the time in front of a screen, you should look 20 meters away every 20 minutes, and keep the gaze for 20 seconds. In this way, the eye muscles get a chance to relax.
