The longer children look at screens, the higher their risk of nearsightedness.
Researchers have discovered that for every hour spent staring at a screen, the risk of developing nearsightedness in children increases significantly.
In light of this situation, experts are warning that young children need to limit their exposure to electronic devices and should spend more time playing outdoors.
Myopia, a condition where the eyeball is longer than normal, making it difficult to see distant objects clearly, is becoming increasingly common globally. According to projections, by 2050, up to 40% of children and adolescents worldwide may suffer from this refractive error.
Although genetic factors play a certain role in the development of nearsightedness, scientists emphasize that living environment and lifestyle habits are also contributing factors that increase the risk.
In particular, limited exposure to natural outdoor light and spending too much time focusing on close objects, such as when using electronic devices, are factors that may explain the link between screen use and increased rates of myopia.
Recently, researchers in South Korea conducted a large-scale analysis, synthesizing data from 45 studies with over 335,000 participants worldwide.
What they found was alarming: in the group of children, adolescents, and young adults, an average of one hour of screen time per day could increase the risk of developing myopia by up to 21%.
Professor Chris Hammond, an ophthalmologist at King's College London (UK), suggests that, based on the current rate of myopia at around 15% among 12- to 13-year-old British children, new research indicates that the risk of developing myopia could increase by 18% if children use screens for one hour a day, and even skyrocket to 27% if that time extends to four hours.
Beyond just the risk of developing nearsightedness, the South Korean research team also warned that for those who already have nearsightedness, adding an extra hour of screen time each day could increase the risk of worsening nearsightedness by up to 54%.
Upon further analysis, scientists found that the risk of nearsightedness increased significantly with screen time. Compared to non-users, those who used screens for one hour a day were 5% more likely to develop nearsightedness.
This number spikes to 97% if screen time extends to four hours per day. However, after the four-hour threshold, the rate of increase begins to slow down. Notably, the research team found no clear link to the risk of myopia if children use screens for less than one hour per day, suggesting that there may be a certain "safe threshold."
However, the study still has some limitations. Some data are based on self-reported myopia, not accounting for other close-up viewing activities outside of using devices, and accurately measuring screen time remains a challenge. Furthermore, this association is only a correlation; it cannot be definitively stated that screen use is a direct cause of myopia.
In the report, the research team further noted that the use of the devices mainly takes place indoors, meaning reduced exposure to natural light, a factor believed to help protect the eyes, thereby contributing to an increased risk of myopia.
Professor Hammond agreed, stating that the development of myopia is a complex interplay of many factors. However, he emphasized: "This large-scale analysis, along with studies during the Covid-19 lockdown, clearly shows that children being confined indoors and spending too much time in front of screens is a dangerous 'combo' for their developing eyes."
Also expressing support for the research, Professor Rupert Bourne from Anglia Ruskin University (UK) said that the most worrying aspect is that severe myopia can lead to many serious eye conditions, threatening long-term vision.
He said, "These findings could form the basis for educational strategies and public health policies aimed at responding to the growing 'myopia epidemic'."
