Screen time for children: how much is ok?

• There is a link between extended periods of screen time and the development of myopia in children.
• Excessive digital screen time is also linked to dry eye syndrome, digital eyestrain, and poor head and neck postures which can cause pain.
• Children are recommended to have no more than 2 hours of sedentary, recreational screen time a day. This means leisure screen time, outside of school work.
• Teaching children rules such as ‘the elbow rule’ and ‘the 20/20 rule’ help them to form good visual habits.

Using digital devices for learning, homework and leisure time can be in many forms, such as laptop computers, tablets and hand-held smartphone devices. Research shows that screen time can be beneficial to kids when balanced with other activities away from the screens.

Spending too much time on screens is a concern for parents as excessive use can impact development of good vision as well as physical and mental health outcomes.

Children exposed to screens before age 3 are more likely to have developed myopia by pre-school age.¹ Myopia is an eye condition which causes blurred far vision, and is also known as short-sightedness or near-sightedness.

Once myopia develops in children, it typically deteriorates every few to several months. Myopia is a significant concern to quality of life in children and teenagers, and poses a risk to long-term eye health.

When it comes to healthy visual development, the challenge of screens is likely to be the duration of use and how close they are held to the face. Digital devices such as mobile phones and tablets are typically held closer to the eyes than a book.

The mechanism is not completely determined yet, but further research has shown that increased digital device time does lead to more myopia in children, and even more when combined with computer use.²

This association also exists for other types of up-close work, such as reading. Closer reading distances and longer duration without a break appear to be more strongly linked with myopia than just the activity of reading itself.³

A 2011 study published in the Journal of Paediatrics suggested 47% of children were spending more than two hours a day on screen time for entertainment,⁵ and by 2019 that number had skyrocketed to 98% in the US.⁶

More recent research showed that children aged 6 to 10 years increased their amount of leisure time spent on screens more than any other age group during the COVID lockdowns, and that this had impacts on diet, mental health, eye health and physical activity.⁷

A report from early 2022 found that children aged 8 to 12 years now spend 5-and-a-half hours per day on screen media, compared to an average of 4 hours 44 minutes per day in 2019.

The World Health Organization has made specific recommendations on screen time for children aged 4 and under, in relation to physical activity and sleep guidelines. It has produced guidelines on physical activity for children aged 5 and older and adults, but not on screen time. This recommendation becomes more complex in school-aged children, where screens are increasingly used in formal education settings.

This means that limiting screen time which is purely for entertainment is important. When families pay attention to their media consumption at home, and parents monitor their children’s digital access, the amount of screen time reduces along with positive improvements in sleep and school performance.⁸

Screen time can encourage sedentary (immobile) behavior, which can have numerous impacts on physical and mental health in children. The World Health Organization recommends the following physical activity guidelines for children aged 5 to 17 years:

• At least an average of 60 minutes per day of moderate-to-vigorous intensity, mostly aerobic, physical activity, across the week
• Incorporate vigorous-intensity aerobic activities, as well as those that strengthen muscle and bone, at least 3 days a week
• Limit the amount of time spent being sedentary, particularly the amount of recreational screen time

Research is indicating that 'co-viewing' screen-based content with your child can have positive benefits. This leads to 'active mediation' of the digital media to which children are exposed, offering opportunities for screen time to helpful to social and language development.

Examples of co-viewing include:

• Watching a TV program with a child and talking about what is being seen, singing along, or asking them to repeat words or content out aloud
• Screen time together which involves playing or creating interactions
• Discussing the content afterwards.

From an eye health point of view, putting content onto a TV screen instead of a tablet or smaller digital device reduces the demand on the visual system. This can also make it easier for parents to monitor digital content as it is easier to glance at from a distance and to hear, when doing other tasks.

Video-chatting is another example of 'quality' screen time which can foster relationships and increase language skills. This is the exception-to-the-rule of recommendations limiting all screen time in babies and toddlers.

Parents can feel less able to monitor screen content as children get older, but in younger children it is especially important. One study found that children aged 5 to 8 years were unable to identify potential dangers in online content to be able to employ internet safety behaviours.⁹

Research points to the value of open family discussion on digital media usage, including setting time- and activity-related goals.⁸

When it comes to eye health and reducing the risks of myopia, there are three simple rules which you can teach your children on screen time.

1. The elbow rule. This is where your child should try to keep an elbow-to-wrist distance between anything they are viewing up close, and their eyes. Try it yourself, and show them at home – make a fist, put it next to your eyes, and where your elbow sits is the closest any screen or book should get to your eyes when reading. This helps to avoid very close viewing distances (less than 20cm) which are associated with increased visual effort and development of myopia.¹⁰ 
2. The 20/20 rule. This is where your child aims to take a break from reading every 20 minutes, for 20 seconds. He or she should look across the room for those 20 seconds, to relax the focussing muscles in the eyes before recommencing reading or screen time. This is to avoid prolonged time spent in close-up vision - more than 45 minutes without a break has been linked to myopia.¹⁰
3. The two-hour rule. This is limiting leisure or recreational screen time, outside of school work, to less than 2 hours per day.

There are other effects that screen usage can have on vision and eye health. These can affect children, teenagers and adults with heavy screen usage.

1. Dry eyes: When using a screen, viewing at closer distances and when concentrating, we tend to blink less. This causes the front part of the eye that normally keeps the eye wet, healthy and comfortable (the tear film) to dry out. Children who spend more time on their smartphone are more likely to have dry eyes,¹¹ which can cause blurry vision and discomfort, and interfere with comfortable contact lens wear. It is important this is managed well with your optometrist or eye doctor, as ‘dry eye’ sounds simple to fix, but can often be a complex and long-term condition.
2. Digital eyestrain: Your child may complain of headaches, itchy eyes or sore eyes after extended periods of time spent using a screen, especially screens held very close. These are symptoms of digital eyestrain, which has become more common in children, especially due to screen-based remote learning during the COVID pandemic.¹² Digital eye strain can be due to a combination of dry eye symptoms, undiagnosed vision problems or other issues like glare sensitivity. Adhering to the Elbow rule, the 20/20 rule and the two hour rule will help alleviate these symptoms.

Blue-light blocking coatings on spectacle lenses (glasses) can reduce eye strain for some people, when spending a lot of time looking at back-lit screens.

There is a small amount of evidence that they can improve sleep quality in adults with self-reported insomnia, but may not have an effect in those with normal sleep patterns. Claims about these coatings protecting the health of the retina have not been supported by evidence.^13,14

The best advice is to pick this type of coating for your child if they feel more comfortable looking through it at a screen.

• Set screen timers. This is easy to do in digital device settings, and can be customized to lock out of certain apps after certain duration or times of day, including setting passcodes for access.
• Enable the 'Screen Distance' setting on iPhones and iPads - to help you monitor screen viewing distance and prevent viewing at closer than 30cm. Read more in our article: Why the iPhone and iPad 'Screen Distance' setting should be enabled for children.
• For other devices download MyopiaApp. Myopiaapp measures how closely the device is being held, and darkens the screen if it’s held too close, revealing the screen again when it’s held back at the ideal distance or further. Developed by an international partnership of scientists and optometrists, early research on this app has shown it effectively modifies screen time behavior, making a dramatically positive difference to the demand placed on the eyes.
• Be a good screen time role model yourself. Set your own timers and check in on your own habits. There is a strong link between parental screen time and that of their children.¹⁵ Set up screen-free times in the family day (eg. meal times) and screen-free places in the family home (eg. the dinner table and kids’ bedrooms).