Grinding sparks, cut-off wheel fragments, chipping slag and chemical splashes all reach the eye faster than a blink, and the damage is often permanent.
Safety glasses are rated to ANSI Z87.1. The standard Z87 marking means the eyewear passed basic impact testing; Z87+ means it passed high-velocity impact testing, which is the relevant rating for grinding and cutting. Lenses should be polycarbonate, which is far more impact-resistant than glass or acrylic.
Lens tint follows the task. Clear lenses for general work and indoor use. Grey and brown tints reduce glare outdoors. Mirror coatings reduce glare and radiant heat. Light amber and yellow lenses increase contrast in low light and are used in dull or indoor conditions. Welding-specific glasses are shaded for light torch and cutting work where a full helmet is not needed.
Fit matters as much as rating. Wraparound styles protect from the side; goggles seal around the eye and are required for chemical splash and fine dust. Over-the-glass styles fit over prescription eyewear. Fogging is the main reason people take eye protection off, so anti-fog coating is worth having.
