All About Blue Light and Your Eyes

I don’t know about you, but screen time in our house has skyrocketed during this quarantine time. Not only for myself, but also for my two kids. I’m spending more hours working on my computer and the kids are doing most of their schoolwork on a screen – reading, math, and meetings with their teachers. I know it’s necessary, but I want to make sure I’m doing what I can to protect their young, vulnerable eyes.

What is Blue Light?

Light is measured in nanometers – a unit of measurement equivalent to one billionth of a meter. Visible light tends to run between 400 and 780 nanometers, and blue light ranges from 400 to 500 nanometers. The low end of that, around 400 to 450 nanometers, is where the eye damage can occur because it has more energy per photon of light than other colors in the visible spectrum. The higher end of the blue light spectrum, somewhere between 459 and 484 nanometers, impacts the sleep cycle.

Where Are You Exposed to Blue Light?

The vast majority of our blue light exposure comes from the sun, but other sources include:

  • Fluorescent light
  • LED lighting
  • CFL (compact fluorescent light) bulbs
  • Flat screen LED TVs
  • All our digital devices: smartphones, tablets, and computer monitors.
  • Blue light exposure you receive from screens is small compared to the amount of exposure from the sun. However, because of the close proximity of the screen to your eyes and the length of time spent looking at them, we are gradually being exposed to more and more blue light for longer periods of time.

Is Blue Light Exposure Harmful?

Low amounts of exposure to blue lights have not been proven harmful; however, overexposure can cause problems with eye health. It’s similar to exposure to the sun – a minimal amount is a good source of vitamin D and helps regulate our sleep patterns, and too much damages the skin.

When it comes to screen time via digital devices, the jury is still out regarding exactly how much exposure is too much. People have only been using smartphones and tablets for eight-plus years, and the damage from blue light takes time to accumulate. It’s a little early to tell exactly how much damage can be caused by overexposure to blue light just from our devices.

What Are the Effects of Blue Light Overexposure on The Eyes?

Short-term overexposure to blue light is associated with eye fatigue, blurred vision, burning eyes, headaches and sleep disorders.

A more serious and long-term issues is age-related macular degeneration (AMD). The Schepens Eye Institute reports, “the blue rays of the spectrum seem to accelerate AMD more than other rays of the spectrum.”  

The macula is the center part of the retina. It allows us to see color and highly detailed images at the center of our field of vision. When overexposure to blue light happens, the waste products (ie: oxidative buildup) aren’t carried away fast enough and we start to get drusen (small yellow deposits under the retina) and other complications. Macular degeneration can result in wavy or blurred vision, and if the condition worsens, central vision may be completely lost or worse, cause a person to become legally blind. Aside from wearing sunglasses and blue-light blocker glasses, here are nutrients you can eat to support your eye health. 

Eye Health at Any Age

Obviously, we want to protect our eyes throughout our entire lifetime, not just when we get older. Did you know the majority of our ultraviolet exposure to blue light and ultraviolet light, up to 80 percent, takes place before the age of twenty?? I had no idea! This makes it so important for kiddos to wear sunglasses when outdoors, wear blue-light blockers when they’re looking at screens, and shut down those screens before bedtime.

Here are the best foods for healthy eyes at any age. Here is the best supplement for Eye health!

Blue Light and Sleep

Going to sleep and waking at the same time each day creates a rhythm for your body. Studies show artificial, bright light can disrupt brain activity and alter sleep hormones like melatonin. This keeps us awake at night. Anybody looking at their laptop or smartphone right before bed is overexposing themselves to blue light at the very time of day they should be powering down their eyes and minds.

We recommend everybody, adults and kids, take a break and turn their screens off, ideally two hours before bedtime. Everybody is different, but two hours is a good rule of thumb—and minimally one hour. It’s really important, particularly for kids, because their eyes allow a lot more blue light in.

Your bedroom should be a quiet, peaceful, blue-light free haven.

Blue Light Exposure is Different For Kids

Children are particularly susceptible to blue light exposure for a few different reasons. First, like adults, they’re also spending time on digital devices. Second, kiddos tend to spend more time outdoors than most adults so they get more blue light from the sun. Third, because the structure of kids’ eyes is different, they absorb more blue light than adults. Children’s pupils are much bigger, and the pupil is like a doorway that opens up and lets light into the eye. Also, a child’s lens, the structure within the eye that does the focusing when we’re looking from far away to up close, is very clear when we’re young, along with the vitreous gel that fills the eye. These clearer structures absorb less blue light and allow a lot more blue and ultraviolet light to reach the back of the eye.

Do Blue Light Filtering Lenses Work?

Blue light glasses can be useful at night when blue light from screens can disrupt natural sleep patterns. Our bodies associate blue light with daytime, so being exposed to it when you’re trying to go to bed pushes our internal clock later so it’s harder to fall asleep and harder to wake up in the morning.

While isolated at home and spending more time on electronics, this may be a good time to invest in blue-light blocking glasses and to look for non-tech related activities to do in the evening, like puzzles, crosswords, or reading an actual book (not an ebook!).

Kelly Harrington, MS, RDN

Registered Dietitian Nutritionist for Healthy Goods



  1. Ratnayake K et al. Blue light excited retinal intercepts cellular signaling. Scientific Reports. 05 Jul 2018. 
  2. Chang AM et al. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Jan 27, 2015. v. 112 no. 4:1232-1237. 

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