Question: what are the materials used in making lens?
Answer: Hard Resin (plastic) Conventional hard resin lenses are half the weight of glass lenses and can be tinted to almost any color and density. ... 
Lighter, Thinner Lenses. ... 
Lenses That Darken in the Sun. ... 
Polycarbonate. ... 
Glass. ... 
Single Vision Lenses. ... 
Aspheric Lenses. ... 
Flat Top Bifocals.