They can be made with CR-39, polycarbonate, or high-index lenses. Trivex lenses ($200 for single vision, $400 for progressives) are more scratch-resistant than either CR-39 or polycarbonate lenses.

The frames are fitted with lightweight and shatterproof polycarbonate so there’s no issue here with robustness. Equinox Blue Light — $66 Image used with permission by copyright holder ...

New lenses turn invisible infrared light into visible images, a study found. Humans can now see in the dark -- and even with their eyes closed -- using nanotechnology contact lenses that turn ...