Understanding Blue Light and Its Effects

May 14, 2023

Screens have become a necessity in our work and social lives over the past several years. More screen time means significantly higher blue light exposure.

Associated symptoms are increased eye strain and sleep disruption. Is blue light truly the cause?

We’ve delved deep into the topic of blue light, including potential dangers, the viability of protective glasses and tips to reduce your exposure.

What is Blue Light?

Blue light is one of the several colours on the visible light spectrum, others include:

  • Red
  • Orange
  • Yellow
  • Green
  • Indigo
  • Violet

Each colour in the spectrum gives off a different wavelength and energy level. Blue light has shorter wavelengths and therefore higher energy than other colours.

When referring to blue light we’re typically talking about screens being the source, however, this is not always the case. About one third of all visible light is blue light, emitting from sunlight, fluorescent lights, smartphones and tablets.

Potential Dangers of Blue Light

Sleep disruption: Blue light can disrupt your circadian rhythm. According to a 2019 study from Chronobiology International, exposure to blue light for two hours at night suppresses production of melatonin, the hormone that brings on drowsiness and sleep. Blue light can trick your body into believing it is daytime, making sleep more difficult.

Eye strain: According to UC Davis Health, digital eye strain can be caused by prolonged exposure to screens, as blue light scatters more easily than other lights, reducing contrast. Blue light is not the only issue here, the way in which we use screens is the main problem. “When we’re on these devices, we become zombies,” says Tamiesha Frempong, MD, an ophthalmologist with Mount Sinai Hospital in New York City. “We don’t blink as much as we do in normal conversation, and so the eyes dry out.”. The discomfort we feel from digital eye strain is typically temporary, subsiding after stepping away from the screen.

While not ideal, eye strain from blue light likely won’t cause permanent damage or muscular degeneration. “There’s no evidence that blue light causes damage to the eyes,” Dr. Frempong says.

Are Blue Light Glasses Effective?

As our understanding of blue light and its potential dangers improves, we have seen an introduction of blue light glasses into the market. These glasses have a special feature designed to block blue light from our devices.

Research so far has not found these glasses to be particularly effective. A systematic review from 2017 in Ophthalmic and Physiological Optics found a lack of evidence that blue-blocking lenses help sleep or eye strain. Similarly, the American Academy of Ophthalmology doesn’t recommend the glasses, as there is yet to be sufficient evidence that blue light damages eyes to begin with.

The effects can differ from person to person. You can try blue light glasses and see slight relief from some symptoms of digital eye strain, however there is yet to be proof of significant positive effects.

Tips for Reducing Exposure

Cut down on screen time: Taking regular breaks from your device will greatly help in reducing the harmful effects of blue light exposure. Every 20 minutes, look away from your screen and focus on an object far in the distance for at least 20 seconds.

Take a break from blue light at night: Try to stay clear of devices 2-3 hours before bed. This can help stop blue light from affecting your body’s release of the sleep hormone melatonin. Try reading a book!

Use a filter on your device: Many devices (laptops, phones, e-readers etc.) have a night mode option. This option will turn your device from a bright, blue light to a darker, warmer yellow colour output. Night mode will help ease digital eyestrain and may even help you sleep better.

Consider the lights in your house: Dim, warm-coloured lights are best to avoid unnecessary exposure to blue light.

If you’re interested in learning more about eye health, we interviewed qualified Optical Dispenser and Technician Jason Smith in our blog “Why is Optical Health Important?”, read more here.

Do you have any tips to help combat blue light exposure? Reach out, we’d love to know!

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