get how sensitive can feel your ears

Material, is used to make bulletproof glass is the same thing, is used in the manufacture of shatterproof glasses or sunglasses. This is just an ordinary plastics (polycarbonate) - but it is a very strong material. The lens is made of polycarbonate, don't you worry that you may your eyes damaged in an accident, or (more common) case, if the glasses fall break lens.
Prescription lenses can be quite thick and heavy, if they are made of optical glass, which is used for another reason for the production of plastic lenses. No matter how strong you are prescribed, plastic lens can be compressed, is a very light. This means the wearer look better (not enlarge eye looking for "coke bottle" from behind) and more comfortable. Don't you know the optical glass weighs more than two times as much plastic? If you have to wear a pair of heavy glasses, you will know the pressure point your nose how uncomfortable and painful, can get how sensitive can feel your ears.
Everyone knows what they should not leave their sunglasses and / or prescription glasses (shadow) crossed in the car. This is because the sun warming glasses (if they are a standard made out of plastic), they can ruin so many, in the thermal softening and melting. However, polycarbonate is quite resistant. If you accidentally let them cook on the dashboard, at least not damaged lenses (although you may need a new pair of frames). You want some time on the computer, watch TV time limit. If you spend all day looking at the computer screen, your eyes can be very nervous. Your eyes need rest, so you want to make sure you get enough sleep, in the evening time.
There are many things you can do, to protect your eyes, it comes from the elements of nature, to one of the most basic things to protect them. Sunglasses during the day you can protect your eyes from the cold dry wind, and harmful rays from the sun.