Eye-protectors are worn to keep dust, splinters or chemicals out of eyes. Eye-protectors have plastic lenses, possibly prescription lenses, with integrated or attached side caps that are specially designed and tested for protection against flying particles in accordance with BS-EN 166. In terms of fitting, it is important to ensure there is not too much or too little space between the eye-protectors and the face. Too much space reduces the protection provided by eye-protectors. Too little space may result in the eye-protectors misting up during strenuous work.