In the past, the only meter emitter of UV light and Blue light that we had to contend to was the sun. Today, the sun is still the biggest emitter of damaging UV radiation and HEV, High energy visible light, also known as blue light, but the sun is no longer the only source of blue light.
Science has proven that blue light damages our eyes, specifically our retinas over time. This high energy light may also contribute to or hazed the unset of Age Related Macular Degeneration. It´s not just the sun that we need to worry about anymore, now we have invited blue light indoors.
Our environments are loaded with man made sources with artificial blue lights that can impact our vision. Everything from artificial lighting sources, to our digital devices: Computer screens, flat screens televisions, cfl light bulbs, smartphones and tablets, even ordinary fluorescent light bulbs, all emit damaging high energy blue light. And as this blue light enters the eye, it makes its way to the back to the eye, directly to the macula, and throw photooxidation it damages our retina.
Blue light is the highest energy light that actually makes it to the back of the eye in any significant amount. The blue light spectrum ranges from 400 to 500. The highest energy wave length which creates the greatest damages is 400 to 440 nanometers.
A tiny amount of UV light does reach the eye and is primarily absorbed by the front of the human lens and never reaches the retina. There is a very small window of transmission of UV at 320 nanometers that reaches the retina in very young children, but as we mature that disappears.
The back of the eye, the macula, where AMD forms is thought by many researches to be affected by blue light, which along with other factors, can create cumulative effect which contribute to this generative disease.
So this begs the question: Is all visible light harmful? Not all of it.
When we look at the visible light spectrum, we can see that on the red end of the spectrum, the wavelengths are much longer and have less energy. Just above the visible light, are radio waves, which are slightly longer. The energy level is lower, which is why it´s difficult to use a cellphone in an elevator, the energy level isn't high enough to penetrate, however if we look at the other end of the spectrum we can see UV and HEV lights, and here the wavelengths are much shorter and have much more energy. This high energy is what makes this wavelengths potentially dangerous. For instance, we know that extended exposures to UV radiation can cause sunburn.
High Energy Visible Light which is blue light, is in close proximity to UV light, and this is the visible light that we are so concerned about today.
We now experience this light indoors, and that time when we were never exposed to it before, like evening hours and bedtime, the constant presence of this wave length in our modern environment has held professionals and retina specialist worried about its potential for damage and contribution to AMD.
Imagine an old car, left out in the weather, over the first few years the cars paint washes away in the open air, think of this as the first stage of macular degeneration. If we left that car in the weather for a few more years, the exposed metal begins to rust, that's the second stage and it leads to dry AMD. If we leave the car outdoors even longer, the rust will join together and destroy the structure of the car and it will completely collapse. This is stage 3, or wet AMD, and it often leads to functional blindness.