1.56 high impact resistant lens has been categorized as one of safety lens, and there are 5 major benefits comparing with PC lens.

1. Weight: It has lighter weight comparing with Polycarbonate (PC)  
2. Optical: It has much higher Abbe value (44) comparing with PC (29) so Its material is crystal clear  
3. Resistance: It has more Impact and chemical resistane comparing with PC material. Even the 200g iron ball drops from the height of 1.27m onto the center of the lens, it won't be broken.
4. Its UV block is 400nm.
5. It can be dyed very easily, while PC lens can't.

More importantly, Its material is suitable for rimless frame because the material has very high tensile strength, comparing with PC material that alway crack after drilling.