Lens Materials.

Glass Lenses

Glass

Although glass is the heaviest of the lens materials, it is often the choice in harsh environments.  Glass retains its shape when exposed to cold or hot temperatures.  Glass is more scratch resistant than most plastics and provides the best clarity in vision.
Plastic Lenses

Plastic

Plastic lenses are half the weight of glass lenses and have excellent optical quality.  The CR-39 plastic remains a popular low cost lens for daily use, but can be quite heavy in higher power prescriptions.

Polycarbonate Lenses

Polycarbonate

Polycarbonate lenses are up to 10 times more impact-resistant than plastic or glass lenses.  They are lighweight and provide 100% protection from teh sun's UV rays.  Polycarbonate lenses are a good choice for comfort, durable, and outdoor applications.
 

Trivex Lenses

Trivex

Trivex is a newer lens material developed in 2001. Like polycarbonate, Trivex is thin, lightweight, and more impact-resistant than CR-39 plastic or glass lenses.  Trivex, however, has less chromatic aberration than polycarbonate lenses producing crisper optics.

 

Hi-Index Lenses

Hi-Index

Hi-Index lenses are thinner than polycarbonate and Trivex lenses.  This material is recommended for those who require a strong eyeglass prescription to correct nearsightedness, farsightedness and/or astigmatism. Hi-index lenses are the most asthetically pleasing lenses, especially in thin frames.