All About Blue Light and Your Eyes

Screens are a big part of daily life—whether for work, school, or entertainment. With so much screen time, it's important to understand how blue light impacts eye health and sleep quality.

What is Blue Light?

Light is measured in nanometers (nm), with visible light ranging from 400 and 780 nm. Blue light ranges from 400 to 500 nm, with the lower end (400 to 450 nm) 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 (459 and 484 nm), influences your sleep cycle.

Where Are You Exposed to Blue Light?

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

  • Fluorescent light
  • LED lighting
  • CFL (compact fluorescent light) bulbs
  • Flat screen LED TVs
  • All our digital devices: smartphones, tablets, and computer monitors.

While blue light exposure from screens is minimal compared to the sun, the close proximity and duration of screen use increase the risk of overexposure.

Is Blue Light Exposure Harmful?

In moderation, blue light is beneficial, helping regulate sleep-wake cycles. However, excessive exposure—especially from screens—may contribute to:

  • Eye strain and fatigue

  • Blurred vision

  • Headaches

  • Sleep disturbances

Long-Term Effects of Blue Light on Eye Health

One major eye health concern 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's responsible for sharp central vision, can suffer oxidative damage from prolonged blue light exposure, potentially leading to vision loss.

The macula 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.

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Protecting Your Eyes at Any Age

Eye health starts young—about 80% of lifetime UV and blue light exposure occurs before age 20. Children’s eyes absorb more blue light due to their larger pupils and clearer lenses, increasing their risk.

Ways to protect your eyes:

  • Wear sunglasses outdoors

  • Use blue-light filtering glasses for screens

  • Limit screen time before bed

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.

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Blue Light and Sleep Disruption

Your body’s internal clock, or circadian rhythm, relies on light cues. Blue light at night disrupts melatonin production, delaying sleep and making it harder to wake up refreshed. To promote better sleep:

  • Power down screens 1-2 hours before bedtime

  • Use dim, warm lighting in the evening

  • Keep bedrooms free of artificial light sources

Blue Light Exposure is Different For Kids

Children are particularly susceptible to blue light exposure. 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 Glasses Work?

Blue-light filtering glasses may help reduce strain and improve sleep quality, especially when used in the evening. Combining them with screen-free nighttime activities—like reading a physical book or doing puzzles—can further support eye health and rest.

With screen time increasing, protecting eye health and sleep patterns is more important than ever. Small adjustments—such as wearing blue-light-blocking glasses, adjusting screen settings, and limiting evening exposure—can make a big difference for both kids and adults.

Kelly Harrington, MS, RDN

Registered Dietitian Nutritionist for Healthy Goods

 

References:

  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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