How much screen time is harmful to kids?
Children and their phones are inseparable today, and all that reading and playing games on their handheld devices may be harming their eyes.
“Screen time” refers to the amount of time a person spends staring at the digital displays of computers, tablets, and smartphones. Many studies find children routinely engage in more than two hours of screen time per day. And it’s very likely most kids actually spend significantly more time staring at screens than their parents think they do.
A study says that 30% of parents find their children experience at least one of the following symptoms after spending more than two hours of screen time per day-
- Neck/shoulder pain
- Eye strain, dry or irritated eyes
- Reduced attention span
- Poor behavior
Any of these symptoms could potentially affect academic performance and social interactions.
The rapid rise of myopia, or nearsightedness, worldwide has been linked to increased use of and exposure to electronic devices.
In Singapore, for example, 65% of students in Primary 6 are myopic. In the United States and Europe, where myopia rates traditionally have been lower, around half of the young adults now suffer from myopia compared with 25% in the 1970s.
The LED screens of computers and portable digital devices emit a broad spectrum of visible light. Most of these light rays are harmless, but a portion of the light emitted by these screens is relatively high-energy visible light called “blue light.”
Blue light has shorter wavelengths and higher energy than other visible light rays. And laboratory research suggests that certain bands of blue light may be harmful to the light-sensitive retina of the eye over time.
Blue light also plays an important role in regulating our body’s circadian rhythm. This is basically an internal clock running in our brain and cycles between alertness and sleepiness at regular intervals over a 24-hour period. It’s also called our sleep/wake cycle.
Too much exposure to blue light at the wrong time of day can disrupt a person’s normal sleep/wake cycle, which can have serious health consequences.
Possible risks from too much screen time for kids can be categorized as immediate or long-term.
Immediate risks from too much screen time generally occur relatively soon after repeated blue light exposure. Many of these risks are associated with circadian rhythm disruption caused by staring at digital screens well into the night, which can make it much harder to fall asleep at a normal time.
Sleep disruption can be especially problematic for children, leading to daytime drowsiness and poor performance in school because. Disruption of the sleep/wake cycle also can eventually lead to weight gain and obesity-related health problems.
The simple truth is that the long-term risks of incremental blue light exposure from frequent use of digital devices are not yet known. This is because previous generations have not been exposed to comparable levels of blue light from digital devices from childhood.
It will probably take several decades before the long-term effects of extensive screen time for kids are better understood. But there is already some related research that suggests it may be wise to limit blue light exposure starting at an early age.