Blue light and sleep
Sean Cain, a sleep researcher and associate professor of psychology at Monash University, says Australian people are increasingly exposed to artificial blue light as a "health problem."
Exposure to blue light at bedtime can affect our sleeping capacity in three ways: by suppressing melatonin production in our body (helping us to sleep), raising alertness and influencing the internal time of our body (or circadian rhythm).
"Although it may be 11:00, you signal the clock that it is a day that it is several hours before, and then it is harder to sleep," explains Professor Cain.
There is also evidence that exposure to blue light can affect the quality of sleep you have during the night: a study by Swiss scientists in 2013 found that exposure to blue light is even at relatively low levels (ie sitting in a room lit by a standard LED bulb) sleep (the healthiest sleep) that man did earlier at night.
Because it's not just a problem your phone is causing. Although people are exposed to less blue light every day than we would get out of the sun while living mostly outdoor lifestyles centuries ago, our exposure is now through artificial sources in unnatural times, especially when the sun falls.
"Most Australians have a lot of blue light in their environment because of the decision to switch to more energy-efficient LEDs," says Professor Cain.
"That's okay because we saved some money on energy, but replaced the light that had less influence on our internal clocks. Now we have these LEDs that are very blue enriched and we have them in our houses within reach beds."
Can Blue Light Damage Eyes?
The short answer to this question is: yes, but probably not at the levels you have put to it.
Much of the marketing around blue lenses is focused on using the screen during the day – Bailey Nelson's website claims their filter "helps reduce eye strain and fatigue caused by screens and devices," while the blue light Oscar Wylee is "for those spending their days ahead of the computer screen "- and how it can supposedly lead to eye strain.
However, Melbourne optometrist and Optometrist Australia spokesperson Sophie Koh says that more evidence is needed on whether exposure to blue light has a specific eye strain, as a result of "limited, smaller studies and unofficial evidence".
"Research is being done in this area and there are a number of other components that contribute to digital eye strain or" computer vision syndrome "," he says.
As for more serious eye problems, it is unlikely that this could be caused by your smart phone.
A New Zealand governmental scientific organization report of 2018, Royal Society Te Apārangi, found that while retinal damage could occur after a high intensity of exposure to blue light, it would require a level of blue light much larger than that emitted by the LED screen.
With this proof, Koh says "at this stage … you do not have to worry that computers or phones will" erase "our retina."
"Recent research has shown that, even under extreme conditions, blue-light exposure from computer screens and mobile devices is less than absorbed by natural daylight, which is below international safety limits," he says.
Blue glasses: is it worth the investment?
If you are worried that you will be sitting at your computer all day, Koh recommends looking for an optometrist to avoid common vision problems such as uncorrected refractive errors (which may be prescribed) or dry eye.
There are other measures, such as the 20-20-20 rule – every 20 minutes on the screen and at least 20 meters (6 meters) within 20 seconds – or using an application such as F.lux or Apple Night Shift to filtered the blue light on the phone, which may be useful.
But if you are trying to improve the quality of your sleep, Professor Cain says he will be "very supportive" to someone who wears a blue-glass jar filter in the evening, especially by inserting glasses at the same time each night to encourage the body to develop a regular circadian rhythm.
However, he warned that during the day he would have glasses with strong blue-light filters, as this could "potentially" affect alertness.
"It was not tested directly, but we know that blue light is warned during the day, so exposure to a lot of blue light during the day can be quite good, not only because it alerts you, but [also] gives the body a strong signal that it is a day, "he says.
"If you block it, you are in a situation where there is not enough signal for your clock to distinguish between today and the night. I think it would be a terrible idea to wear these things all day long."
And if you want to buy glasses with blue light so you can write in the early hours of the morning, try to: In the end, no special glasses will quench the phone you will give to your bedtime.
"Obviously, if you use the device in a way that makes you more active – if you are looking at working emails or worried about the next day – it will be harder to fall asleep."
Mary Ward is deputy editor Sydney Morning Herald and Age.