Blue Light (not so) Special: A Two-Minute Tech Read

Ian Bryant | Jun 24, 2019

You’ve likely heard talk about the negatives of “blue light” from the screens that surround us.

How harmful is that blue light and do we need to stay away from it?
The human body runs on a timer called the Circadian Rhythm. This is the body’s most optimal schedule and deviating from this schedule can affect one’s mental — and even physical — health. This rhythm is guided by one major thing: light, and specifically natural light. Natural light changes colors throughout the day, warm in the morning and evenings and cool during the day. The notion of  “temperatures” of light were created by William Kelvin in the mid 1800’s. He discovered that heating a block of carbon made the carbon glow in different colors at different temperatures. During the day when light is at its most blue (6500k and higher) it boosts attention, reaction times, and mood — and it also suppresses melatonin, thus keeping us awake and active. In the evening, when the natural light changes to a warmer (4000k and lower) temp, the body’s circadian rhythm changes and the body starts to produce melatonin, making us relaxed, tired, and eventually ready for sleep. People working night shifts will have to work harder by creating their own atmosphere to support these colors and keep with their own rhythm.

The Electronic Culprits

LCD and LED screens like those on our computers, tablets, phones, and TVs can emit light well above 6500k. Looking at our computers during the day is not going to change our circadian rhythm, but looking at them at night can change that rhythm  and start to cause  problems. It may not be noticeable immediately, but over time this exposure can start to cause unwanted effects. According to the ANSES Opinion research paper linked below, blue light is able not only to disrupt the circadian rhythm, but can also affect the duration and quality of sleep and cognitive performance in general.  We can make changes to keep this from happening.

Those Changes Are …

The hard answer that no one wants to hear is simply this: We shouldn’t use any of these devices two hours before going to bed. Manufacturers are getting it and some now have options for “night mode.” This mode shifts the color temperature of the display to a lower, warmer temperature keeping the blue (higher kelvin) temperature away from the eyes. Another body of research suggests that light intensity in the evenings can affect one’s rhythm. As little as 8 lux (about double the light intensity of a night light) when it is dark can cause disruptions and even damage to the eyes. The forgotten or unnoticed culprits are the millions of LED light bulbs (above 6000k) that are currently in houses all around the world. Those should not be used in the evenings or should be removed and replaced with warmer bulbs or “smart” bulbs that can change their colors throughout the day manually or automatically.

In short, there are fixes to this particular technological problem — but sometimes turning off and unplugging can be the best option.
On eye damage from LED light
The ANSES opinion
NOTE: This Emerging Trends piece is brought to you by CEDIA’s Technology Advisory Council and Technology Application & Innovation department.