I have been asked a lot lately about Blue Light and screen time and potential problems with vision and eyes especially with Children. The piece below if from an Association of Optometrists leaflet : Screen Time – Facts for Parents.
Screen time — facts for parents
Most parents worry how much time their child is spending on
digital devices. Here are some facts about screen time.
What is blue light?
Sunlight contains red, orange, yellow, green and blue
light rays. Combined, this spectrum of coloured light
rays creates what we call ‘white light’ or sunlight.
Depending on where they fall on the spectrum, light
rays have long wavelengths (with less energy) or short
wavelengths (with more energy).
Blue light is a high-energy visible light and has shorter
wavelengths. It is known as blue light because it is
on the violet-blue band of the spectrum. Blue light
is naturally present in sunlight but is also something
we can see from screens such as TVs, computers,
smartphones and tablets.
Can blue light damage my child’s eyes?
There is currently no scientific evidence that blue light
causes damage to the eyes. However, there is evidence
to suggest that carrying out near tasks, involving
looking at something close-up, such as using mobile
devices, screen time and reading a book, can increase
eye strain for those who do this for long periods of time.
What is digital eye strain?
Digital eye strain happens when a lot of time is
spent using near vision, for example, reading on
screen or playing online games. Digital eye strain
does not cause permanent damage to your eyes but
can be uncomfortable. One of the main symptoms
is temporary blurred vision but other signs such as
sore and tired eyes, dry eye and headaches are also
associated with digital eye strain.
Can blue light affect my child’s sleep pattern?
Using screens close to bedtime may contribute
to poorer sleep, which may mean your child’s
concentration levels are lower during the day. This
may be because blue light is linked to the suppression
of the hormone melatonin which makes us feel sleepy.
However, there is a range of other factors linked to
Can blue light filtered lenses help?
Some people report that lens coatings that filter blue
light make their eyes feel more comfortable or are
helpful before bed, but there is no clear scientific
evidence to support this. There is also no evidence
that these kinds of coatings prevent eye disease.
Why have I heard that blue light is harmful to eye health?
Several studies have been carried out into the effects
of blue light, and research in this area is still ongoing.
Some past studies have revealed that exposure
to blue light can lead to changes in animals’ eyes.
However, because the time and intensity of exposure
to blue light in these studies was far more than that
of natural daylight and that of screens, this does not
show that blue light is harmful to eyes.
Is there a link between screen time and short-sightedness?
Short-sightedness, or myopia, is increasing
throughout the world. Family history, ethnic
background, environment (living indoors, in cities)
and carrying out near tasks, such as screen use,
have all been linked to the development of myopia.
However, there is no clear evidence to suggest that
screen time alone is the direct cause. But, there is
good evidence to suggest that children who spend
more time outdoors are at lower risk of developing
Some Tips to help keep your child’s eyes healthy
Get them outdoors — regular play and exercise can help prevent or
reduce the development of myopia (short-sightedness). Studies show two
hours of outdoor activity a day is ideal.
Using night settings, if your device has them, may help children sleep
by reducing the amount of blue light given off by the screen during
Make sure digital devices are turned off at least an hour before bedtime.
Book your child in for a sight test every two years, from the age of three,
or more often if your optometrist recommends it.