In my home, the debate over the ideal brightness level for screens is a constant struggle. My tendency to dim the screens to almost complete darkness seems to physically torment my partner, who often reacts with squinting and groans.
To my defense, my concern likely stems from the countless warnings we’ve heard about the potential hazards of extended screen exposure. Since smartphones have become prevalent, we’ve been alerted to the possible dangers of artificial blue light emitted by screens. Taking these warnings seriously, I decided to invest in blue light-filtering prescription glasses when I bought a new pair last spring.
However, I’ve found myself questioning the actual harm, if any, posed by artificial blue light. So, I set out to uncover a conclusive answer for both of us.
Understanding Blue Light
Blue light is a part of the visible light spectrum, found near the violet end, characterized by its high energy. While the sun is the primary source of blue light, artificial sources include the screens of our devices and LED lighting, which have replaced traditional incandescent bulbs due to their eco-friendliness.
Is Blue Light Dangerous for Our Eyes?
With Canadians spending an average of 70 days annually on their phones, it’s crucial to explore the implications of blue light on eye health. Fortunately, recent studies suggest that there is no clear evidence linking artificial blue light to eye damage in the general population. Some findings indicate that screens emit under 10% of the blue light hazard threshold defined by the International Commission on Non-Ionizing Radiation Protection.
However, it’s important not to get too comfortable; these studies also highlight a notable absence of high-quality, long-term research on this subject. One review by the European Scientific Committee on Health, Environmental and Emerging Risks stresses the need for ongoing monitoring of this issue.
If blue light isn’t the culprit, what could be causing the discomfort from long hours of screen use? The American Academy of Ophthalmology suggests it’s likely a case of computer vision syndrome, also known as digital eye strain. This condition can manifest as headaches, dry or watery eyes, blurred vision, and overall eye discomfort.
Maintaining Eye Health
Adopting a Mediterranean diet and consuming foods rich in lutein and zeaxanthin can support eye health. Other essential vitamins and minerals for optimal vision include:
- Vitamin C
- Vitamin E
- Zinc
Does Blue Light Impact Sleep Quality?
Our circadian rhythm relies on light to manage our sleep-wake cycle. In daylight, light suppresses melatonin production, keeping us alert. However, exposure to light at night can inhibit melatonin and disrupt sleep. While blue light is commonly blamed for sleep issues, recent studies have also identified yellow light as a factor.
A 2023 study involving human participants found no significant difference in circadian rhythms when exposed to either blue or yellow light. However, a prior study using mice indicated that yellow light might have a more negative effect on their circadian rhythms compared to blue light.
What’s the Conclusion?
While current research does not substantiate the harmful effects of artificial blue light, its long-term risks remain uncertain. As for my new glasses, the evidence supporting the efficacy of blue light-blocking lenses is lacking.
This gives my partner the upper hand in our ongoing discussions about screen brightness, but at least I can take comfort in the fact that I’ll hear fewer groans from now on.
Impact of Blue Light on Children
As we age, our eyes become less susceptible to light. Younger individuals, especially children with larger pupils, are more sensitive to light’s effects. A recent study indicated that bright light exposure in the hour leading up to bedtime significantly suppressed melatonin in preschool-aged children, leading to sleep disturbances.
Furthermore, a review by the European Scientific Committee on Health cautioned that while blue light exposure may not be harmful, bright blue LED lights in toys could cause retinal damage.
This article originally appeared in the February 2025 issue of alive magazine.
