Blue light and sleep
Sean Kane, a sleep researcher and assistant professor of psychology at Monash University, says the growing effect of Australians on artificial blue light is a “health problem.”
Exposure to blue light before bedtime can affect our ability to sleep in three ways: by suppressing the production of melatonin in the body (which helps us sleep), by increasing our alertness and affecting our body's internal clock (or circadian rhythm).
"Despite the fact that it may be 11 pm, you give a signal to your watch that it is daytime, that it is a few hours earlier, and then it is more difficult to fall asleep," explains Associate Professor Cain.
There is also evidence that exposure to blue light can affect the quality of sleep that you have throughout the night: a study by Swiss researchers in 2013 showed that exposure to blue light even at relatively low levels (i.e., sitting in a room, illuminated by a standard LED light), can reduce the amount of slow-wave sleep (the most restorative type of sleep) in a person at the beginning of the night.
Because problems arise not only with your phone. Although people are exposed to less blue light every day than we could get from the sun, living mostly outdoors a few centuries ago, our exposure now occurs through artificial sources in unnatural time, especially in indoor lighting, when the sun sets.
“Most Australians have a lot of blue light in the environment because of the decision to switch to more energy-efficient LEDs,” says Associate Professor Cain.
“It's good to save some money on energy, but it replaced the light, which less affected our internal clocks. Now we have these LEDs, which are very rich in blue, and we turn them on in our homes all the way up into bed. "
Can blue light damage your eyes?
The short answer to this question is yes, but probably not at the levels at which you are exposed to it.
Much of the marketing of blue light lenses focuses on using the screen throughout the day — Bailey Nelson's website claims that their filter “helps reduce eye fatigue and fatigue caused by screens and devices,” while Oscar Wiley's blue light lens designed for those who spend their days in front of the computer screen ”- and how it could supposedly lead to eye strain.
However, Melbourne optometrist and Optometry Australia representative Sophie Co says that more evidence is needed on whether blue light, in particular eye strain, is a concept that emerged as a result of "limited, small studies and unconfirmed data."
“Research in this area is ongoing, and there are many other components that contribute to digital eye strain or“ computer vision syndrome, ”she says.
As for more serious problems with vision, this is unlikely to be caused by the habit of your smartphone.
A report by the Royal Society Te Apārangi, a New Zealand government research organization for 2018, showed that although retinal damage may occur after exposure to high intensity blue light, this would require a blue light level much higher than the level emitted by the LED screen.
With this proof, Ko says: "at this stage … we don’t need to worry about computers or phones" roasting "our retina."
“Recent studies have shown that even under extreme conditions, the level of blue light from computer screens and mobile devices is lower than that of natural daylight, and this is below international safety limits,” she says.
Blue light glasses: are they worth the investment?
If you are worried that your eyes may hurt when you are sitting at your computer all day, Koch recommends that you seek advice from an optometrist to rule out such common eye problems as uncorrected refractive errors (which can be corrected with a prescription) or dry eyes.
There are other measures, such as following the rule of 20-20-20 – every 20 minutes, look up from the screen and at a distance of at least 20 feet (six meters) at a distance of 20 seconds – or use an application such as F.lux or Apple Night Shift to filter the blue light on your smartphone, which can be useful.
But if you are mainly seeking to improve the quality of your sleep, Associate Professor Cain says that he will “greatly support” someone wearing glasses with a blue light filter in the evenings, especially wearing glasses at the same time every night to encourage the body to develop regular circadian rhythm.
However, he cautions against wearing glasses with strong blue light filters during the day, as this can “potentially” affect vigilance.
"This has not been verified directly, but we know that blue light signals during the day, so exposure to a large amount of blue light during the day can be very useful, not only to alert you, but [also] giving your body a strong signal that this is the day, "he says.
“If you block it, you will find yourself in a situation where your watch does not have enough signal to determine the difference between day and night. I think it would be a terrible idea to always wear these things of the day. "
And, if you want to buy glasses with blue light to send text messages in the early hours, keep dreaming: ultimately, no special glasses will beat your phone until you go to bed.
“Obviously, if you use devices in a way that makes you more active — if you are looking at working emails or are worried about the next day, it will be harder for you to fall asleep.”
Mary Ward is the deputy editor of The Sydney Morning Herald and The Age.