Most of us now live our lives lit by low energy artificial light, such as LEDs and compact fluorescent bulbs. We also use smartphones, tablets, computer screens and TVs for large parts of the day. All of these light sources operate in the bluer end of the light spectrum, leading to a significant shift in the wavelength of light entering the eye. You may have heard that blue light can cause ocular damage and disturb sleep patterns, and that using special blue light blocking lenses can 'protect' you from these 'hazards'. However, these claims are often disputed and recent court cases and GOC fitness to practice hearings show the level of confusion surrounding the subject. So what do you really need to know and what can you ignore...
What is blue light?
Most of us know the harm that ultraviolet light (UV) can cause, we all use sun cream on holiday to protect our skin from damage. However, blue light (also known as High Energy Visible or HEV light) exists just beyond UV on the electromagnetic spectrum. The longer wavelength of this HEV light means it can penetrate further into the eye than UV light, reaching and potentially damaging, the important receptor cells of the retina.
Where does blue light come from?
Blue light actually sits at the edge of the visible spectrum of light, so most light that enters the eye will contain wavelengths of blue light to some extent. However, certain sources of light have higher levels of blue light. Sunlight, LEDs and compact fluorescent light all contain peaks of blue light. So exposure to sunlight as well as the use of smartphones, tablets and many modern TVs and screens will increase blue light absorption at the retina.
How significant is the risk to eye health?
First, the good news. The International Commission on Non-Ionising Radiation Protection (ICNIRP) has concluded that exposure to blue light from phones, tablets and other common artificial light has little to no risk of retinal damage. It is however worth noting that the risk increases as the distance to the light source is reduced, so don't hold your phone too close (we're looking at all you short-sighted people right now!) and move your desk lamp a little further away.
The not so good news is that sunlight poses a higher risk. Unsurprisingly, sunlight has a peak of all wavelengths of light across the electromagnetic spectrum, including HEV light. There is growing evidence that exposure to certain wavelengths of blue light is damaging to retinal cells and that it is cumulative over time. We are now fairly certain that exposure to sunlight is a risk factor for Age-related Macula Degeneration (AMD).
What can we do about it?
Back to the good news. The simple way to protect your eyes from harmful HEV light is by wearing blue light blocking glasses that filter these wavelengths of light. There are various spectacle lenses now available that protect the retinal cells from HEV light, to a greater of lesser extent. The best lens I know of currently is the Lutina range from Tokai, one of our two main suppliers. Lutina is a clear lens alternative that offers 94% protection from this harmful light, while still allowing the important visible light through to give us clear vision.
One word of caution, most sunglasses offer little or no protection from HEV light. The use of sunglasses is important for UV filtration, to protect the skin around our eyes, as well as the cornea and crystalline lens. But virtually no UV light reaches the retina. The higher energy HEV light is not absorbed by sunglass lenses. Fortunately, Lutina is also available as a tinted lens, so we can offer blue light blocking sunglasses with this higher protection as well.
Hopefully this clears up the subject of blue light a bit. If you want any further information on the subject of blue light, eye health and eye protection then please get in touch. If you would like to find out more about Lutina please visit us in store and we'd be happy to have a chat.
Reference: The information above was adapted from an article written by Donald Cameron and published in the etCETera journal.