Does it seem like everyone is talking about blue light these days? There’s a reason for it. If you’re reading this on one of your screens (smartphone, laptop, tablet), you’re exposing your eyes to blue light now, though that might be a bit simplified. Blue light is just one colour on the light spectrum that we’re exposed to on a daily basis. Even the sun and indoor lights have some level of blue light, it’s just a matter of figuring out how to manage it. But back to the screens for a minute. As we spend more time staring at monitors, iPads, and smartphones, we increase the amount of blue light we’re exposed to — and that’s where blue light filtering glasses might help.

What is blue light anyway?

For starters, blue light doesn’t actually appear blue to the naked eye. “Blue light is the portion of the visible light spectrum with the shortest wavelengths (400 to 500 nanometers or nm) and with the highest energy, hence it is often referred to as high-energy visible (HEV) light,” according to Dr. David Friess, OD, FAAO, of the Eyesafe Vision Health Advisory Board. The eye does not block blue light well. The cornea and lens block UV rays from reaching the back of the eye (the retina). Blue light passes through these structures and can reach the retina.

Blue light exposure may increase the risk of macular degeneration and does contribute to digital eye strain. “There are also two primary domains of blue light highlighted,” Friess says. One kind of blue light damages cells of the retina, while other blue light affects our wake/sleep cycle.” This “good” blue light “appears to contribute to physical and emotional health,” he says.

What does blue light do to your eyes?

Blue light is everywhere, and it can throw off our natural body clocks. “We get constant exposure to blue light from ambient sunlight, computer screens, tablets and mobile phones,” said Dr. Rohit Varma, MD, MPH, founding director of Southern California Eyecare and Vision Research Institute. “The brain associates blue light as daytime, so if a person is exposed to blue light for long periods of time during the night, blue light makes it more difficult for us to fall asleep at night and wake up in the morning,” Varma said. While there’s no definitive information on the exact amount of blue light you can be exposed to before showing serious side effects, “long-term exposure to screen light can have some intense serious side effects,” said Caroline Dubreuil, product marketing manager for EyeBuyDirect. “Headaches, disorientation and loss of sleep are just the start of it” said Dubreuil, whose website, like many eyewear retailers, sells blue light blocking glasses.

Benefits of blue light lens coatings

All that screen time may be causing digital eye strain. “There are many causes for eye strain,” said Dr. Raj K. Maturi, MD, a spokesman for the American Academy of Ophthalmology. “Blue light is just one of them.” Maturi said being too close to your screen doesn’t help: “We strain our eye muscles when looking at such a close target.” Late-night screen time throws off sleep patterns, because blue light affects melatonin (the sleep hormone) levels. How? Decreased light at night signals the body to generate sleep hormones like melatonin. Blue light disrupts these signals, and less melatonin is generated. For some, blue light filtering glasses are a great way to combat the eye strain and sleeplessness that come with excessive screen time.

The key takeaway:

Do you need blue light lenses? Maybe. The way you choose to protect your eyes from harmful blue light isn’t as important as consistently doing just that.

Next week’s post will be Part 2 of this article