General Face mask
When using a twist-knot wire-brush, cutting or grinding disk on a hand-held grinder (typically a 100 or 115mm type), it is essential that a full face mask is used. Only last weekend I heard of a case of a disc breaking and removing part of someone's face. It's not JUST the eyes when using powerful hand-held grinders. Additonally, even with twist-knot wire-brushes, particles being thrown off can be red-hot when considerable pressure is applied.
This is a Uvex (French) mask and goggles that is BS rated and can be bought from Axminster Tools/Screwfix etc. Believe I paid about £15, and has served me well, having taken quite a few large chunks of metal and floods of that white VW underseal blasted at it.