Parents are likely to have come across the term "blue light" more than once if they have been researching the effect of excessive screen time on health. This form of light has been found to have a disruptive effect on our sleep as well as our children’s sleep. While it may seem hard to believe, the verdict (and science) is out on the exact relationship shared between blue light and sleep quality.

The effects of blue light on sleep

Blue light is essentially light of a particular wave length out of the entire spectrum of light. This means digital devices are not the only source of blue light as it can occur naturally as well (with sunlight for example). However, artificial light sources such as those from digital devices and fluorescent light bulbs have been found to be more concentrated in blue light than any other sources. What exactly is so special about blue light that makes it so disruptive to sleep?

• Effects on melatonin production

Blue light has such a profound impact on your child’s sleep simply because it directly affects your child’s body production of the sleep hormone melatonin. So how does blue light affect this important sleep hormone? Melatonin is responsible for making your child feel sleepy, and blue light suppresses the production of this important hormone. This is why sunlight wakes your child up naturally in the morning and your child tend to feel sleepier in dark environments. Even though digital screens are such a small light source compared to natural sunlight, it still has significant effects on children’s sleep cycle. This is because their brain perceives blue light through the melanopsin receptors behind their retina, so all the blue light from their devices can reach their brain.

• Effects on circadian rhythm

Blue light’s role in maintaining melatonin levels in your child’s body makes it a huge factor in controlling their body’s circadian rhythm. Your circadian rhythm is responsible for telling their body when it’s time to sleep and wake up, so any disturbances to this cycle will have an effect on their sleep. As a result, your child may experience difficulty falling asleep or even staying asleep.

In short, blue light interferes with your child’s sleep in two ways – first by disrupting your child’s body production of sleep-inducing hormones, and second by throwing your child’s body natural circadian rhythm off-balance. By negatively affecting the quality of your child’s sleep, blue light exposure can prove to be really detrimental to your child’s health. Apart from sleep-related issues, there are two other negative side effects of blue light exposure that are just as worrying.

​​Other consequences of blue light exposure

1. Digital eye strain

Children get a lot of blue light exposure via their digital devices and this can lead to strained eyes, where your child’s eyes feel sore and dry and their vision becomes less clear. Along with the physical aches associated with spending long hours in front of a digital screen, this can lead to a lot of physical discomfort.

2. Increased risk of macular degeneration

The consequences of blue light exposure go beyond just a mere eye irritation and can even lead to serious vision-related problems. Prolonged exposure to blue light over time can cause cell damage in your child’s retina and make them more susceptible to macular degeneration, a problem that may lead to a permanent loss of vision.

5 ways to minimise your child’s blue light exposure

1. Put their devices away at least two hours before bedtime

Since the blue light emitted by their digital devices will affect their sleep, the easiest solution to the problem is to stop them from using their devices in the hours leading up to their bedtime. The less screen time your child engages in, the better. However, if going device-free is honestly impractical, don’t worry: studies have found that your child can continue using your devices up to two hours before bedtime, after which their melatonin production will be affected. It may be hard to abstain from their favourite devices, but two hours is a reasonable target to aim for!

2. Adjust screen brightness and turn on night light filters

The simple act of lowering your child’s screen brightness can play a significant part in reducing their blue light exposure. Lowered screen brightness means less blue light, so your melatonin levels won't be disrupted as much. When their night-light filters are on, they will get an extra layer of protection - the longer wavelengths in the night-lights are less harmful to their melatonin production. You can even download special light altering filters that will change the blue light into orange or red light, both of which have less melatonin-blocking effects.

3. Use devices with smaller screens

The amount of blue light children exposes themselves to is proportional to the size of their device's screen and the distance between said screen and their eyes. You can easily minimise your child’s blue light exposure by getting your child to use devices with a smaller screen (such as a smartphone instead of a laptop) and viewing the screen from a further distance.

4. Change your home lights to warm lights or “smart” lights

Apart from changing the way your child uses digital devices, you can also modify the lights at home to make them more sleep-friendly. Warm lights don’t affect melatonin levels the way bright lights do, so get some night lamps with warm lights or invest in “smart” lights that automatically switch to warmer shades at night.