A survey by the Bureau of Labor Statistics found that 3 out of 5 workers injured, had no eye protection. Eye protection should be worn whenever there is a danger of flying particles, chemicals, dusts and mists, molten metal splash or spatter, or blood and infectious materials.
Most lenses are either glass, plastic, or polycarbonate.
Glass lenses provide good scratch resistance, withstand chemicals, and allow for prescriptions. But glass is heavy and can be uncomfortable. Plastic and polycarbonate lenses are light weight, are less likely to fog, and protect against welding splatter. These lenses are not as scratch resistant as glass. Polycarbonate lenses are superior to glass and plastics in strength and impact resistance.