Study Links Excessive Screen Time in Childhood to Rising Cases of Myopia
Screen addiction – whether it’s a cell phone, computer or tablet – is a growing concern. And if it was already a growing problem before 2020, after the pandemic the addiction exploded. The WHO (World Health Organization) recommends that children up to 5 years of age should not spend more than one hour a day in passive activities in front of a smartphone, computer or TV screen. But the reality is that only 1/3 of children between 2 and 5 years of age actually comply with the maximum daily suggested times. For those under 2 years of age, the situation is even worse: less than 1/4 follow the recommendation.
The age at which the eyes are fully formed is undetermined, but it is a fact that at least the first few years of life are crucial for their formation. Rosa Maria Graziano, an ophthalmologist at the University of São Paulo School of Medicine, explains: “In the first five years of life, the eye grows a lot. In compensation, the cornea and the lens, which are more curved, need to flatten. So, there is a significant amount of change in children’s refraction in these first few years.”
Inside the cornea, there is a muscle called the ciliary muscle, which has the function of focusing on nearby objects. When we look far away or without focus, the muscle is relaxed. However, when we focus on a nearby object, the ciliary muscle makes an effort to adjust vision. “When you use near vision, you make the lens need to change its degree, and for this, it needs a ciliary muscle to make a movement, an accommodative effort, so that the image stays focused,” says Rosa Maria. In practice, there is no difference between using screens and doing other activities that focus the eyes closely, such as reading a book or writing.
The problem is that, while in childhood, without excessive screen time, children would go outdoors and alternate between activities that required them to look at objects up close and at a distance, today the situation is no longer the same. With the eye still developing, overstimulating the lens and ciliary muscle can cause later complications. The consequence is usually myopia, a condition in which the ability to focus on distant objects is impaired.
Practical consequences
Especially after the pandemic, computers, cell phones and televisions became an integral part of children’s lives; even school hours began to be mediated by screens. The consequence was a sudden increase in myopia in children: according to a study by the American Medical Association, the increase in myopia diagnoses among 6-year-old children was 28.8% in 2020 and 36.2% in 2021.
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The importance of paying attention to this goes far beyond simply seeing well. Impaired vision, especially in children, can affect many different areas of life. The ophthalmologist comments on a case she experienced in her clinic: “I have seen children who were treated as having ADHD, even with Ritalin, and in fact, they had a high degree of myopia, which is why they got tired [of concentrating on the activity]. Before they had a headache or eye pain, they would stop doing it.”
Children are not the only ones affected by screens. Although they do not suffer from the degree of variation as children do, since their eyes are already more developed, adults are not immune to the tendency to spend their lives with their eyes glued to something. Regardless of age, spending uninterrupted periods of time focusing on something very close causes the body to wear out. “The muscle that moves the lens for close-up vision is just as much a muscle as the leg muscle or the arm muscle: it also gets tired. This is one of the reasons why people who work with computers all the time end up with greater visual fatigue at the end of the day than if they had taken breaks,” explains Rosa Maria.
Furthermore, she states that our bodies instinctively adapt our eyes to blink less when there is a focused focus. When our vision is relaxed, “you blink about 15, 16 times a minute, and that lubricates your cornea. When you are focusing on an object to read or to look at a screen, whenever you are focusing your eyes, your brain tells you not to blink. You automatically reduce the number of times you blink to five, six times a minute.” The consequences are red, irritated eyes at the end of the day.
What to do
In the case of children, the ophthalmologist recommends that they have periodic check-ups at odd-numbered years: at 1, 3, 5 and 7 years of age. If health or financial conditions make this impossible, she asks that they have an exam at least at age 5. If the child shows signs of hyperactivity, distraction, difficulty completing activities or mental fatigue, a visit to the ophthalmologist is recommended at any age.
In general, both children and adults are advised to take breaks to rest their eyes while working on the computer or paperwork. According to the American Society of Ophthalmology, the ideal is to take 1-minute breaks every 20 minutes. But Rosa Maria says that, to accommodate what is possible, going to the bathroom, drinking some water or doing anything that allows your eyes to close and relax momentarily every hour is much better than nothing.