 PPG named the material Trivex because of its three main performance properties, superior optics, ultra light weight, and extreme strength.Trivex is a relative newcomer that possesses the UV-blocking properties and shatter resistance of polycarbonate while at the same time offering far superior optical quality (i.e., higher Abbe value) and a slightly lower density.Its lower refractive index of 1.532 vs. polycarbonate's 1.586 may result in slightly thicker lenses depending upon the prescription.