The Dangers of Artificial Blue Light: Fact or Fiction?

A deep dive into blue light research and its findings

Within my household, there’s no greater point of debate than the appropriate screen brightness level of digital devices. My obsession with reducing the intensity to a notch above darkness seems to cause my partner physical pain, as the action is often met with intense squinting and a groan.

In my defence, my vigilance is likely the product of repeated warnings of prolonged screen exposure. Since the advent of smartphones, we’ve been cautioned about the negative effects of artificial blue light emitted from screens. Heeding these warnings, I decided to err on the side of caution when I purchased my new prescription glasses last spring, splurging for blue light protection.

But in the months since this purchase, I’ve been left wondering: how harmful, if at all, is artificial blue light? I dug deep in search of a definitive answer to this question—for you and for me.

What is blue light?

Blue light is one of the colours that can be perceived by the human eye along the visible light spectrum; it is located near violet at the high-energy end. Exposure to large amounts of high-energy light, such as invisible ultraviolet (UV) rays, has a higher potential to cause retinal damage, skin damage, and circadian rhythm disruption.

While the biggest source of blue light is the sun, it’s artificially emitted from the screens of electronic devices and LED lights, which have readily replaced incandescent bulbs due to their reduced environmental impact.

Is blue light harmful to the eyes?

According to informal surveys, Canadians spend an average total of 70 days a year on their phones, making the topic of blue light consumption and its effect on our eye health worth examining. But according to research, Canadians can breathe a sigh of relief.

Recent research findings examining the effects of artificial blue light have concluded there is no evidence to suggest that it is harmful to the general population. In fact, they note that some studies found screens emit less than 10 percent of the blue light hazard limit set by the International Commission on Non-Ionizing Radiation Protection.

But don’t increase your screen brightness just yet—these publications also observed a serious lack of high-quality and long-term research into the topic. One of these reviews, published by the European Scientific Committee on Health, Environmental and Emerging Risks (SCHEER), calls for the situation to be monitored closely.

But if blue light isn’t to blame, then what’s causing the discomfort we feel following prolonged periods in front of a screen?

The American Academy of Ophthalmology says you’re likely suffering from computer vision syndrome, an ailment caused by uninterrupted and overly focused periods of screen time. Also known as digital eye strain, it can cause headaches, dry or watery eyes, blurry vision, and eye soreness or irritation.

Keeping your eyes healthy

The Mediterranean diet and other foods rich in lutein and zeaxanthin help to promote eye health. Other vitamins and minerals found to contribute to healthy vision include:

vitamin C
vitamin E
zinc

Does blue light affect the quality of our sleep?

Our body’s circadian rhythm uses light to regulate our sleep-wake cycle. During the day, light helps to suppress our melatonin secretion, keeping us alert and functional. But when we’re exposed to light at night, the resulting suppression of melatonin production can prevent us from falling and staying asleep.

While blue light has been singled out as the main culprit in sleep disruption, two new studies also point the finger at yellow light.

A 2023 study conducted on humans found that there was no difference in participant’s circadian rhythms after being exposed to both blue and yellow light. When a previous study tested the same effects on mice, research showed that yellow light was more detrimental to their circadian rhythm than blue light.

So, what’s the verdict?

While current research negates the harmful effects of artificial blue light, the jury is still out on its long-term dangers. As for my enhanced glasses, there is no evidence to support the protective benefits of blue-blocking lenses.

While current research gives my partner the upper hand in future debates over screen brightness levels, I can take solace in the fact that I’ll no longer need to hear as many groans.

Blue light and children

As we grow, our eyes become less sensitive to light. Given their young age and larger pupil size, children are more sensitive to the effects of light on their eyes. A recent study examining melatonin suppression in preschool-aged children found that bright light of a single intensity in the hour before bedtime had a strong effect on the suppression of melatonin, which can cause sleep problems.

When it comes to blue light, SCHEER’s review found that while emissions may not be harmful, bright blue LEDs in toys may induce retinal tissue damage.

This article was originally published in the December 2024 issue of alive magazine.