In our experience with forensic disciplines, we have identified a number of tasks where eye protection should be mandatory. These range from routine housekeeping duties, to working with solvents and chemicals in analytical labs, hazardous light sources, and firing ranges.
Keep eye protection in sight when mixing or using chemicals and cleaning solutions, and any job that can produce a splash.
Goggles are used to guard against splash hazards like mixing or using chemicals and cleaning solutions. Many goggles are designed with venting to prevent fogging during use but these are not suitable against splashes or very fine dust. We tested a set recently where if you were splashed on the forehead, the liquid was directed to the eyes by the vents. So be careful in your selection.
Face shields offer an extra level of protection; however, they should always be used with either safety glasses or goggles as splashes, particles, or chemicals can get around the shield and into the eyes. Also, it is a common tendency to lift face shields to check the work progress thus leaving the eyes unprotected if used alone.
From: Keeping Safety in Sight by The Safety Guys