Welding goggles protect a welder's eyes from sparks, heat, UV light and infrared light. While arc welding requires a full welding helmet, some types of welding require only welding goggles. Welding goggles have filters that darken the lens and prevent retina burns caused by UV and infrared light. Higher filter numbers mean greater protection. Lenses can also be anti-fog to maintain vision during temperature and humidity changes.