This is a fast video demonstration of how you can test your sunglasses if they have UV protection at home.
Get a UV flashlight.
Go to a semi-dark room and shine the light on money banknote so you can see the symbols only visible with UV light.
Shine the light directly through your glasses (like in a demo video) if you can’t see the lines or symbols your glasses are 100% UV protected.
If you still can see the symbols DO NOT wear the glasses – ask for a refund.
What is happening?
When you are shining the light directly through the glasses they block the UV light completely. As the UV light can’t pass the UV reactive fibers in the banknote do get any direct UV light and they do not shine.
Eyes and the sun
Too much sun can damage the eyes. As with skin damage, it is the ultraviolet (UV) radiation from the sun which causes problems. Damage to the eyes from UV radiation is cumulative, meaning it builds up over our lifetime and can have a permanent effect on our eyes and eyesight.
UV radiation is invisible to us and is composed of 3 main wavelengths: UVA, UVB and UVC. UVB rays are mostly absorbed by the cornea (the outermost layer on the front of the eye) and so do not penetrate through to the retina, unlike UVA radiation which passes through the cornea to the lens and retina of the eye. UVC radiation is filtered out by the earth’s atmosphere.
As well as from the sun, UV radiation is emitted in very high amounts by solariums and sunbeds.