Author: Vanessa Thai
Developmental and Behavioural Optometrist
Central Health Southside – Child Development Team
Digital screens have become an integral part of children’s daily lives, as they are extensively used for both educational and recreational purposes. This article aims to explore the impact of screen time on visual development and eye health in children, as well as provide recommendations for effectively managing it.
How Much Screen Time?
The World Health Organization (WHO) provides the following guidelines for screen time in young children:
- 0 to 2 years: No screen time, except for live video
- 2 years: No more than 1 hour per day, with less time
- 3 to 4 years: No more than 1 hour per
For children aged 2-4 years, it is recommended to limit screen time to 1 hour per day, preferably with parental involvement. Co-watching and engaging in activities like reading together can support language development and learning.
What Is Blue Light?
Blue light is present in our environment, emitted by the sun, artificial lighting, and digital screens. In moderation, it serves beneficial purposes, such as regulating sleep-wake cycles, mood, and cognitive performance. However, excessive exposure in close proximity, particularly from digital devices, may lead to premature ageing of the eyes and visual strain.
What Effects Can Screen Time Have on Children?
Prolonged screen time in young children can have negative effects on normal development, including active play, learning, attention skills, and eye movement abilities. It is associated with higher rates of obesity and global mortality and contributes to developmental delays, such as slower language development, reduced motor skills, communication difficulties, poor social skills, and cognitive challenges. Research shows that preschoolers who spend more than two hours per day on screens have an increased risk of developing ADHD.
The World Health Organization (WHO) highlights the importance of physical activity, sufficient sleep, and reducing sedentary behaviour for young children. Using screens too close to bedtime negatively impacts sleep quality, which is crucial for child development.
Preschool-aged children who have been regularly exposed to screens are at a higher risk of developing myopia. There is increasing research indicating the link between screen time and myopia development in children under 10 – the crucial stage of visual development, and this link continues even in the teenage years.
Children commonly look at screens at close distances and blink less frequently while concentrating. As a result, the tear film responsible for maintaining eye moisture begins to dry out leading to blurry vision and discomfort.
Also known as Computer Vision Syndrome (CVS), digital eyestrain is characterised by symptoms such as headaches, eyestrain, irritation, blurred distance vision after screen use, dry/red/itchy eyes, and glare. CVS is caused by the visual demands imposed by screen use, including focusing at a fixed distance for extended periods, maintaining long periods of attention, and looking at a bright flickering screen.
Reading from screens is more challenging for the visual system, leading to slower reading rates and increased eye strain symptoms. Poor posture while using screens can increase the risk of eyestrain and musculoskeletal pain. CVS is becoming more prevalent among children due to increased screen use, especially during the COVID-19 pandemic.
Managing Screen Time
Co-viewing screen-based content with children can have positive benefits, promoting social and language development. Putting content on a TV screen instead of smaller devices reduces visual strain and allows for easier parental monitoring. Video chatting can also be considered quality screen time for fostering relationships, social development, and language skills.
Ensuring that the room lighting is similar to the screen brightness can help reduce visual stress. Alternating periods of intense screen viewing with outdoor activities that require distance vision can also aid in visual development.
Working Distance & Taking Breaks
Our eyes are naturally more at ease when focusing on objects that are farther away, typically beyond a distance of six meters. To minimise eyestrain, it is important to teach children good visual habits – one being the “Harmon Distance” which refers to the recommended adult forearm’s distance between the eyes and screens.
Another good visual habit is following the 20-20-2 rule by taking a 2-minute break every 20 minutes to look at something in the distance at least 20 feet away to help relax and reset the eyes.
Blue-Light Blocking Glasses
Overexposure to blue light can have negative effects, but more research is needed to fully understand the extent of these effects. Blue-light blocking coatings on glasses may reduce eye strain for some individuals, so it is advisable to choose these coatings if they make your child more comfortable while using screens.
Apple has a “Screen Distance” setting for iPhones and iPads, which automatically alerts users if the device is held too close to the face. This feature aims to protect children from the potential risks associated with viewing screens too closely for extended periods.
Research has shown that holding screens too close and for too long increases the risk of developing myopia and can lead to eyestrain and discomfort. By enabling the “Screen Distance” setting, parents can help their children maintain a safe viewing distance and potentially reduce the risk of myopia and other eye-related issues. There are no known disadvantages to enabling this setting, and it aligns with the recommended “Harmon distance” for screen viewing distance.
A behavioural optometrist can assess focus and eye alignment systems, evaluate the ability of the binocular vision system to maintain visual attention and provide solutions such as computer glasses, vision therapy, visual hygiene advice, or drops for dry eyes to manage digital eyestrain. Regular eye tests are recommended to ensure optimal visual system functioning.