Have you ever been told that you need blue-light blocking lenses or else the light from your digital devices will harm your eyes?
Well, in a nutshell, “blue light from electronic devices is not going to increase the risk of macular degeneration or harm any other part of the eye” says Harvard Health , and there is little evidence to show that using such lenses prevent digital eye-strain based on a double-blind test .
We could have just showed you some images of people getting eye strain and sell you some magical lenses.
But nope, we are not gonna do that.
‘The Time Is Always Right To Do What Is Right’
– Martin Luther King Jr.
The Sun = Blue Light. And all other light really.
Blue light is one component of the visible light spectrum, which includes the colours that you’ll see in a rainbow – remember ROYGBIV anyone? Naturally, the brighter the light, the more blue light we can expect. The sun is a powerful source of light – measuring about 1600000000 nits, while mobile phone screens come in at about 500 nits . So, we are more likely to be exposed to more blue-light (and all other light) from the sun than from our digital devices.
Visible light ranges from 380nm to 750nm (or 400nm to 700nm, depending on which website you’re reading).
At the lower end of the wavelength spectrum, there is more energy. If we go even further down beyond Violet light, we have Ultra-Violet, X-rays, and Gamma rays, which we know are harmful. If we go higher up the spectrum beyond Red light, we get Infrared, which is what your TV remote puts out for you to control the channels.
Blocking Ultra-Violet and Violet
Hence, our lenses are made to block not just Ultra-Violet light which is invisible, but also part of Violet light which is visible. Our High Energy Visible (HEV) 420 lenses, which comes as a default for our single-vision eyeglasses package, blocks most of violet light from 400nm to 420nm. Violet light, being close to Ultra-Violet (100nm to 400nm), has higher energy compared to the other colours in the visible light spectrum, and can be harmful in larger amounts , hence the need for it, especially if spending more time outdoors in daylight.
No need to block non-existant death rays from phone
We do not use the “blue-light blocking” lenses with a blue-coating to ‘prevent eye strain from using digital devices’, as they simple reduce the amount of blue-light passing through, and there is little evidence to support using blue-light filtering lenses to prevent digital eye strain . The American Academy of Ophthalmology does not recommend any special blue-light blocking eyewear for computer use . However, blue-coatings are available as an option if you prefer it.
But my eyes feel tired after staring at my computer!
Take a break, blink, have a drink, and walk around. Your eyes can get tired after excessive near work (visual fatigue), be made worse due to dry eyes as we tend to blink less when we are focused. Other ‘computer vision syndromes’ can be a result of poor posture or lighting, or even screen flicker.
But someone told me their lenses block 90% of blue light!
Blue light is well in the visible spectrum (unlike ultra-violet which is invisible to the human eye), so removing most of the blue light will just make things look really yellow.
So think twice if someone tells you that blocking blue light means no more headaches, no more dry eyes, and no more fatigue! 🙂
 (Harvard Health, 2019)
 (Rosenfield et. al., 2020)
 (Herman, 2010 ; Morrison, 2018)
 (Sapkota, 2016 ; Youn, 2009 ; Grimm, 2001)
 (Vimont, 2021)