Protecting Your Eyes from Harmful Blue Light
By now, you've probably heard the buzz about harmful blue light and ways to block it. But what exactly is blue light and how damaging is it to our eyes? Visible light is a little more complex than we may think.
From being outside in the sun, turning on a light indoors to looking at digital devices results in our eyes being exposed to a variety of visible (and sometimes invisible) light rays that can have different effects. Rays on the red end of the visible light spectrum have longer wavelengths and have less energy. Rays on the blue end of the spectrum have shorter wavelengths and more energy. The rays just beyond the red end of the visible light spectrum are called infrared; they're warming, but invisible. On the other end of the spectrum, blue light rays with the shortest wavelengths are sometimes called blue-violet or violet light. This is why the invisible rays just beyond the visible light spectrum are referred to as ultraviolet (UV) rays. UV rays have higher energy than visible light rays, which is how we get those gorgeous suntans. But, too much exposure can cause those painful sunburns and can even lead to skin cancer. On the other hand, UV rays (in moderation) have some benefits, like supplying our bodies with vitamin D.
Like ultraviolet light, blue light has both benefits and dangers. Blue light is everywhere; it's practically unavoidable. Sunlight is the main source and being outdoors is where most of us get exposed to it. Indoor blue light can be found in fluorescent and LED lights and flat screen tvs. Computers, tablets, cell phones and other digital devices also emit significant amounts of blue light. While the amount of light these devices emit is only a fraction of that emitted by the sun, it's the amount of TIME we spend using these devices and how CLOSE we hold them to our face that's causing concern for the long-term effects on our eyes.
The adult human eye is very effective at blocking UV rays from reaching the retina, which is found at the back of the eyeball. However, the same can't be said about blue light; virtually all visible blue light passes through the eye and reaches the retina. Because blue light is penetrating all the way to the retina, too much exposure can cause damage to the light-sensitive cells, which ultimately can lead to macular degeneration. Also, high-energy blue light scatters easier than other visible light and is not as easily focused. When we're staring at devices that emit high amounts of blue light, this unfocused visual "noise" reduces contrast, which is what contributes to eye strain and fatigue.
Not all blue light is bad, though. Research shows that some blue light exposure boosts alertness, helps memory and cognitive function and elevates mood. Also, blue light is important in regulating our body's natural awake/sleep cycle. Exposure to blue light during the day helps maintain a good cycle, but too much blue light late at night can disrupt this cycle, which can cause sleepless nights and daytime fatigue.
So, how do we protect our eyes from this harmful blue light? By wearing a lens with blue-blocking technology, such as Thera Blue. Thera Blue is a lens designed to filter out between 80-85% of the damaging blue light rays that would otherwise pass right through the lens to our eyes. Check out our Facebook page to see a quick demonstration of a lens without vs. a lens with this blue-blocking technology! Thera Blue is available in a wide range of lens designs and is also available on sun lenses. Make sure to ask for this on your next pair of eyewear!
Don't need a prescription? You can find non-prescription "computer" glasses pretty much anywhere these days-just make sure they're good quality! There are also filters available that block blue light from reaching your eyes without affecting the visibility of the screen.
-Jen
*Facts from - allaboutvision.com