First It Was Sleep, Now Your Eyes: Another Warning About Blue Light | KERA News

First It Was Sleep, Now Your Eyes: Another Warning About Blue Light

Jul 1, 2019

New scientific evidence suggests the blue light coming from LED lighting may be harmful to your eyes. There are preventive steps you can take. But a local ophthalmologist thinks it’s not cause for worry.

The blue light from LED lighting is similar to what comes from electronic devices like cell phones and computers.

“A lot of the difference is just based on intensity,” said Dr. Zachary Robertson. He's an ophthalmologist with Parkland Hospital and an assistant professor of Ophthalmology at UT Southwestern Medical Center. “Our smartphones, our tablets our computers do often rely on LED technology or something similar, and they do emit blue light. But the intensity is not as great as LED headlights coming at you or some of the other things that we use LED for.”

INTERVIEW HIGHLIGHTS

What is blue light? "Blue light is sort of the high end, the high energy level, of the visible light spectrum. And it sort of goes from blue all the way down to red. We see blue light every day. That's sort of why the sky is blue. It's because the high energy blue light is refracted by the air molecules and water in the sky. That's really not a new thing. You know we've had blue light around forever. LEDs, however, are fairly new and they tend to produce energy more in the spectrum of blue light. So it's more of a shifted light source toward blue even though to our eyes it may look white or it may look some other variant in color." 

The new study uses the term “phototoxic”: "Phototoxicity occurs when high energy light hits the retina and damages the internal workings of the cells, in the cells that live beneath the retina. And that's true for a number of light sources. A lot of these studies that look at short term damage from high intensity blue light are not done in humans. It's done in a lab setting. And so how that translates directly and what that really means for 'screen time' is still sort of up in the air."

Why "phototoxicity" here isn't as scary as it sounds: "The concern is how much additional blue light are we getting based on our LCD [TVs] or our phones or our tablets. And right now, the long-term, low-level exposure from those devices has been studied to be about the equivalent of a cloudy day in the UK in the dead of winter. So we're still not talking about a whole lot of blue light. All of the studies to date demonstrate that there's no significant evidence that shows that reducing that with blue blocking glasses or filters really changes eye fatigue eye strain or retinal toxicity." 

Any real cause for worry? "People who use their phones or tablets right before bed are getting more blue light exposure than they otherwise would, and in the night. And that may decrease their melatonin production and decrease their ability to fall asleep quickly. I think that is the, at least much more real, imminent risk of LED exposure in blue light exposure is the changes to our sleeping behavior. We don't really know yet fully how that's going to affect the retina."

Protective steps we can take: 

  • Limit screen time as much as possible but not to the extent that you're scared of your screen,
  • Use sunglasses and UV blocking while you're outside 
  • Eat a healthy diet of green leafy vegetables and colorful fruits and vegetables promote retinal health. 

RESOURCES:

Blue Light has a Dark Side

LED lights damage eyes and disturb sleep, European health authority warns

Blue-Light Hazard and LEDs: Fact or Fiction?

Effects of blue light on the circadian system and eye physiology