Spending long hours in front of a computer screen or devouring Netflix each evening is a daily habit for many of us. And if you believe the hype, the blue light emitted from our electronic devices is robbing us of sleep and causing an epidemic of digital eye strain.
Enter blue light blocking glasses, which claim to fix our sleep and alleviate the symptoms of sore, tired eyes for good. But do they work? We take a look at the evidence.
Experts aren't concerned about environmental exposure to blue light – including that emitted from screens.
What is blue light and is it harmful?
Blue light is part of the electromagnetic spectrum, and most of the exposure we get to it is from sunlight. It's also artificially emitted from our digital devices and LED light bulbs.
As blue light is close to UV light in the spectrum – and we know the risks that UV light pose to the skin and the eyes – it's been the focus of many studies, says Dr Nisha Sachdev, ophthalmologist and director at the Australian Society of Ophthalmologists.
"However, I don't believe there's any evidence to suggest that normal environmental exposure to blue light, including that emitted from digital screens, causes any measurable damage to our eyesight," she says.
Optometrist Luke Arundel from Optometry Australia agrees. "The level of blue light exposure from computer screens and mobile devices is less than that absorbed when you step out into natural sunlight – and is below the international safety limits," he says. "So at this stage, we don't need to worry about computers or phones 'frying' our eyes."
Can blue light cause digital eye strain?
It's a question worth asking, given digital eye strain is thought to affect millions of people globally.
In the US alone, a 2016 survey found 65% of adult respondents reported symptoms of digital eye strain – which typically includes dry, irritated eyes, blurred vision and headaches resulting from prolonged use of computers or other devices. But experts are sceptical that blue light is to blame.
"We're a very digital society and this reliance on screens is a relatively new phenomenon in the last 5–10 years," says Dr Sachdev. "And indeed, this year with everyone working from home, I've seen many patients present with symptoms of digital eye strain.
This year with everyone working from home, I've seen many patients present with symptoms of digital eye strainDr Nisha Sachdev, ophthalmologist and director at the Australian Society of Ophthalmologists
"However, I think that the ocular issues we're increasingly seeing are not so much related to blue light but rather to spending hours on digital devices and not blinking as much, which affects lubrication of the eye. Wearing contact lenses for more than the recommended eight hours in one session doesn't help either."
Arundel adds that there have been limited smaller studies and anecdotal evidence linking blue light to eye strain.
"Researchers have shown that high intensities of blue light can damage retinal cells but the majority of this research has been conducted in laboratories or on animal models," he explains.
"More evidence is needed as to whether blue light exposure specifically causes eye strain and research is ongoing in this area."
Blue light may have an impact on your sleep/wake cycle.
What about the links between blue light and sleep?
There have been a number of studies on the effects of blue light exposure in the evenings from LED lights or screens, including that it may interfere with melatonin production, which may have an impact on sleep/wake cycles.
However, it's not known if this leads to adverse health effects, and it continues to be the subject of research, according to Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).
"Good sleep is a result of multiple factors and not influenced solely due to blue light from screen use," says Arundel.
"But limiting exposure to blue light by reducing screen brightness, using night-time apps such as F.Lux and Apple Nightshift and turning devices off at least an hour before bed are strongly recommended for a good night's rest."
What are blue light blocking glasses?
Blue light blocking glasses have special coatings that filter out the blue light that's emitted from electronic devices such as TVs, computer screens, tablets and smartphones. Some of these devices – such as smartphones and tablets – have blue light filters built in that you can 'switch on' which claim to do the same thing.
The glasses or blue-blocking lenses are routinely touted by eyewear companies to help with digital eye strain – and anecdotal evidence is mixed. Some consumers say they don't help much, but in a CHOICE report in 2015 on blue light blocking glasses, some trialists said after using the glasses they 'probably' or 'maybe' slept better.
Do the glasses actually work?
If you're using blue light-blocking glasses to help with digital eye strain, then there's currently limited high-level evidence they work for that purpose. Current lenses may block 6% to 43% of blue light, but blocking all blue light during the day could have other negative effects.
"Blue light, of which the biggest source is the sun, naturally suppresses the body's production of melatonin, which tells our body to wake up," says Arundel.
"Blue light is beneficial during the day because it boosts attention, reaction times and mood – it's actually essential for our general health and wellbeing, so blocking all blue light during the day may adversely affect your body clock or circadian rhythms."
Blue light is beneficial during the day because it boosts attention, reaction times and moodDr Luke Arundel, optometrist, Optometry Australia
What about night-time wearing? Well, a 2017 University of Houston study found that participants who wore the glasses three hours before bed while using digital devices or watching TV experienced a 58% increase in their nightly melatonin levels. However, this was a small study of 22 people.
Other studies have been done to determine whether blue light blocking glasses have other health benefits, adds Dr Sachdev.
"These were small studies, and overall there was a lack of evidence to support using blue-blocking lenses in order to improve visual performance, alleviate eye fatigue or conserve macular health.
"A 2018 study suggested that wearing blue light blocking glasses for one hour before bed may improve sleep quality and alleviate insomnia symptoms, but that would also be the equivalent to having no digital time for an hour prior to sleep."
Book a comprehensive eye exam before investing in blue light blocking glasses.
Do blue light glasses help with headaches and migraines?
If you suffer headaches or migraines after long hours staring at a computer, it makes sense to wonder if blue light is to blame. But is it?
"There's no evidence that blue light blocking glasses will help ward off headaches or migraines," says Dr Sachdev.
"A migraine is more likely to be exacerbated by the brightness of your screen or because you're not taking regular breaks, than exposure to blue light."
Arundel agrees that many things can contribute to eye strain or headaches – which need to be ruled out before you invest in blue blocking filters.
"A comprehensive eye examination with an optometrist will look at your focusing system, whether you need prescription lenses, your eye coordination and whether you have dry eye syndrome."
Are blue light glasses good for night driving?
If you're having issues with night driving, this is a different issue to using blue light blocking glasses to filter out blue light from screens
"At night there's more contrast in the light so we're really talking about contrast sensitivity here," says Dr Sachdev, "and there's no evidence that blue light glasses will help with night-time driving.
"Generally, we find there's often an organic cause for night-time driving difficulties, such as cataracts, that people don't realise they've got. So if you're having difficulties driving at night you need a full ocular examination to rule out any issues that may be causing it."
Where to get blue light glasses
Keen to try blue light blocking glasses anyway? You can buy blue blocking lenses from optometrists – Oscar Wylee will add a blue light blocking filter to any of its frames for $80, while OPSM's BlueGuard lenses will set you back $50 on top of your selected lenses.
Just be aware there is currently no specific Australian standard for blue light filtering glasses or screen protectors, according to the Royal Australian and New Zealand College of Ophthalmologists (RANZCO).
Other ways to reduce eye strain
We'd struggle to lift weights at the gym for hours at a time – but we expect our eye muscles to function perfectly under extreme workloads without a break, says Arundel.
"Even for someone with perfect vision, eye muscles will become sore, tired and fatigued with 'overuse'," he explains.
"A good habit to adopt to avoid this is the 20/20 rule, where every 20 minutes you should look up and into the distance for 20 seconds, to give your eye muscles a break."
Dr Sachdev also recommends keeping hydrated, using lubricating eye drops and turning down the brightness of your screen.
"I've done it myself on all my devices as well as the computers throughout my clinic – and it really does help," she says.