Once upon a time I noticed that something was scratching the inside of
my eyelid. Went to doctor who pulled a small splinter of steel from my
eyeball.
OK. no big deal. But the doctor said, "You have a rust spot on your
pupil which will have to be removed."  This after only having that
splinter overnite.  The rust forms quickly.  Was sent to the
opthalmologist who strapped my head into a frame, put in some numzit,
and proceeded to grind out the rust spot with a rotary grinder. Now I
can assure you that this is a proceedure that you definitely do not want
to undergo.
You really do want to wear safety glasses.

Jim Thompson