Ask Adventure Network. Glass lenses offer better optics and are more scratch-resistant.
Plastic lenses are more shatterproof.
Lenses that filters out infrared light will reduce eye fatigue from intense sun conditions. Wrapped lens to shed wind and debris. Hydrophilic nosepiece to minimize slipping. Polycarbonate or plastic lenses to save weight. Be warned that sport glasses with extreme wraps or curves to the lens make it more difficult for your doctor to grind a lens that will not distort.