18K Golden Eyeglasses Invite a friend Share $10 and 50% off on frames new arrivals get free photochromic lenses free rx glasses this is a real gift
Help Center

Plastic Lenses Material (CR-39) ( Helpful:0 ) Back »

*Refractive index (nd): 1.498 (standard)
*Abbe value (Vd): 59.3
*Density: 1.31 g/cm³
*UV cutoff: 355 nm

 

The lens is light weight compared to glass, and may be made in just about any prescription, though many people with higher prescriptions prefer to use Hi-Index Lenses. The higher the index, the thinner the lenses. Plastic lenses are great for prescription sunglasses due to their tintability factor and you can virtually tint a plastic lens to any color under the rainbow.

 

Developed by PPG during WWII, CR-39, also known as plastic or hard resin, serves as a much lighter lens material (approximately 50% lighter) than glass. CR-39, however, is far less scratch resistant and often must be coated to improve its scratch resistant characteristics.

 

Pros

Lighter than glass
Readily tintable
Less likely to fog

 

Cons

Susceptible to scratching (correctable by coating)
Lower index of refraction makes it less suitable for higher powered prescriptions

Was this answer helpful? Yes(0)

Recommended Glasses at Cheap Prices For You

My Style