It’s All About The Blue Light
Stepping into direct sunlight, flipping a light switch, turning on our laptop or phone… all of these actions result in our eyes being exposed to a variety of visible (and often invisible) light rays.
What is blue light?
Sunlight contains red, orange, yellow, green and blue light rays, depending on the energy and wavelength of the individual rays. Combined, this spectrum of coloured light rays creates “white light” or sunlight.
Without getting too complicated, there is an inverse relationship between the wavelength of light rays and their energy. Rays that have relatively long wavelengths contain less energy, and those with short wavelengths have more energy. Rays on the red end of the visible light spectrum have longer wavelengths and, thus, less energy. Rays on the blue end have shorter wavelengths and more energy.
Around a third of all visible light is considered high-energy visible (HEV) or “blue” light.
A few things to know about blue light:
It’s everywhere - Sunlight is the main source of blue light but there are also many man-made/indoor sources. Most notably, the screens of computers, tablets & smartphones emit significant amounts of blue light. The amount of HEV light these devices emit is only a fraction of that emitted by the sun. Yet the amount of time we spend using these devices and the proximity of these screens to our faces pose serious concerns about the possible long-term effects of these sources of blue light on our eye health
Our eyes aren’t good at blocking it - Virtually all HEV light passes through the cornea and lens and reaches the retina
May increase the risk of macular degeneration - Studies show that too much exposure to HEV light can damage light-sensitive cells in the retina
It increases digital eye strain - Blue light scatters more easily than other visible light, so it’s not as easily focused. When we look at devices that emit a lot of blue light, this unfocused visual “noise” reduces contrast and can contribute to digital eye strain
It impacts our sleep cycle - Some blue light exposure is essential for good health. Research shows HEV light boosts alertness, memory and cognitive function, and even elevates mood. It’s also vital for regulating circadian rhythm — our body’s natural wake / sleep cycle. Too much blue light late at night (e.g. reading a tablet / phone at bedtime) can disrupt this cycle, potentially causing sleepless nights
So if, like me, you are frequently looking at screens I really recommend a blue light filter on your screens and protective blue-light blocking glasses to reduce blue light exposure (and help us all look a little more intelligent while we’re at it!). There are many glasses options nowadays (without prescription) and I really love mine which are from @ambr
