Polycarbonate, also known as poly, was invented by the aerospace industry for gear used on the Apollo space shuttle (helmet visors etc.). It is an impact resistant material that is highly recommended for rimless, safety glasses and sports eyewear. Poly is known for its resistance to chipping or shattering and is 40 times more resistant than FDA requirements. However, once polycarbonate is severely scratched it may loose its impact resistance qualities.
Poly is a flexible material that needs a hard coat to protect it from easily scratching, but also has a natural UV protective nature. However, some patients may be hyper sensitive to the chromatic aberration poly has when using the peripheral viewing area leading to afish bowl effect.