Why using GOOD sunglasses are necessary, and not just on sunny days.
To protect your eyes from UV with Sunglasses it is important to understand UV.
Light is a very complex phenomenon, and we only see a portion of it which we call visible light. Visible light range from 400nm (nanometers) to 740nm of wavelength. Violet has the shortest wavelength and has the highest energy, while red has the longest wavelength and has the lowest energy within the visible spectrum.
This visible light is what enables us to see everything around us when it enters our eyes. But just like visible light can penetrate our eyes the invisible portion of the electromagnetic spectrum can also enter our eyes. Luckily for us, the majority of very dangerous electromagnetic spectrum like X-Ray and Gamma Rays do not penetrate our atmosphere.
But UV still penetrates the atmosphere and can also enter our eyes, and this is where GOOD sunglasses are an investment to the health of your eyes.
So what is UV?
UV is the portion of the Electromagnetic Spectrum with wavelengths just shorter than Violet and range from 10 to 400 nm shorter than visible light. Because UV has high energy it mostly causes damage to our skin but the eye is no exception.
UV is further classified into 3 types, UV-A, UV-B and UV-C.
Firstly, UV-A is known for Aging.
Secondly, UV-B is known for Burning (skin burn).
Lastly, UV-C is known for Cancer (dangerous and can cause cancer).
UV-A has the lowest energy, but it can still penetrate the eye and the lens and even reach the retina. UV-A is linked to Cataract formation and can cause Macular Degeneration.
UV-B has higher energy than UV-A and 100% of it gets absorbed by the cornea. This is why it is highly unlikely that UV-B causes Macular Degeneration but there are some links to Cataract formation. UV-B triggers the production of the formation of Melanin in the skin but high exposure to UV-B can lead to higher risks of skin cancer. On the eyes, UV-B exposure leads to pterygium and acute photokeratitis.
UV-C his the highest energy of the different types of UV and mostly gets filtered out by the Ozone layer.
What is a GOOD pair of Sunglasses?
A pair of sunglasses that filters out UV-A, UV-B and UV-C are all good sunglasses. The filtering of these UV rays happens through the coatings on the lens or the lens material itself.
When to wear these GOOD Sunglasses?
Even though most people only wear their sunglasses when they feel the sun is bright outside or in the summer times, it is important to wear your GOOD Sunglasses whenever you are exposed to sunlight. Even when it is cloudy outside, UV rays still penetrate the clouds and cause damage.
All the major sunglass manufacturers put in a lot of time and money to have their lenses protect you from the harmful UV-Rays. They have to go through a number of tests to be able to label the product as UV protection.
