The truth about blue light exposure

Our eyes are one of the most metabolically active organs in our bodies and are susceptible to oxidative stress — an imbalance between free radicals and antioxidants in the body, which can lead to negative health impacts. When it comes to eye (and general) health, we increasingly hear about the effects of ‘blue light’, but is it all hype or is exposure creating a ticking timebomb?

Among other sources, blue light exposure comes from digital devices. Screen time has been on the rise for the last 20 years. According to survey data from the Employer and Eye Care Provider Screen Time Survey 2020 (conducted by UnitedHealthcare Vision for Eyesafe) and published in the Screen Time Report 2020, that figure exceeds 13 hours per day. Device use has increased even more since the report’s publication, thanks to both working and lifestyle changes ushered in by the pandemic. For individuals and organisations, understanding the effects of blue light exposure and the measures that can be taken to reduce risk has never been more important.

What is blue light?

Blue light is part of the visible light spectrum and makes up the wavelengths between 415 and 455 nanometres. Unsurprisingly, it is literally blue, but the way it affects our eyes is arguably more interesting than its colour. Blue light is the highest energy light that reaches the retina and allows for high oxidation potential. In passing through the cornea and lens, blue light forces the retina (the light-sensitive layer at the back of the eye) to process it.

The good

Despite the wellness movement’s focus on the negative side of blue light, it’s not all bad. In fact, some exposure to blue light is critical to our health and wellbeing.

The largest source of blue light is the sun and exposure is essential to regulate our circadian rhythm — the body’s natural sleep and wake cycle. Exposure to the sun’s blue light in the morning increases our cortisol levels and helps us wake up. It also boosts alertness, helps memory and cognitive function and elevates mood. For anyone who has ever experienced low spirits or struggled to keep focus in winter when the days are short and we spend less time in the sunlight, the impact of underexposure to blue light is clear.

But, as with most things in life, the issue is finding the right balance and avoiding ‘too much’ exposure.

The bad

Too much blue light, or exposure at the wrong time of day, can contribute to circadian rhythm disruption. According to the findings in the Screen Time Report 2020, 78% of employers are concerned about blue light exposure through screen time through phones and other mobile devices including laptops and notebooks, as well as PC monitors. The symptoms most associated with excessive exposure and reported by workers include:

• headache (63%)
• blurred vision (55%)
• dry eyes (50%)
• sleep disruption (36%)
• reduced productivity at work (32%).
   

The Eyesafe organisation brings together experts in healthcare and technology to reshape consumer electronics and the industry’s understanding of device usage, screen time and the impacts of blue light-emitting devices. It estimates that by 2050, five billion people will have myopia (short-sightedness) due to excessive blue light exposure — the majority of these will be young adults. Children are at higher risk of blue light retinal damage, as their lens absorbs less short-wavelength light than an adult’s, allowing more blue light to reach their retina.

Can blue light glasses help?

Blue light glasses can help control the temperature light emitted from a TV, phone or laptop screen. Not all are created equal, of course, so it is advisable to test them. Effective blue light glasses should completely block blue coloured light, meaning you would not see the flashing blue light of a police car when wearing them.

Limiting blue light exposure

One of the key issues with blue light exposure is the relatively short distance between our eyes and our screens. Rather than stay continuously focused all day, it’s helpful to take regular breaks in order to promote vision longevity and prevent blue light burnout. For every 20 minutes of screen use, users should avert their eyes and look at something five or six metres away for at least 20 seconds.

At home, it is recommended that bedrooms remain device-free, blue light-free zones, with warm-coloured lighting and no scrolling before sleep. The ‘night mode’ setting on most smartphones and tablets can be customised to your personal sleep schedule, as can apps for laptops and notebooks.

When in the workplace, exposure may be unavoidable, but many monitors and smart devices now include eye protection technology designed to prevent blue light exposure and damage, so it’s worth investigating available options.

Image credit: iStock.com/Viacheslav Peretiatko