As I do most of my roaming alone, I usually have in my pocket a tiny mirror with which to help myself if a "red pepper" gnat flies into my eye, or something else of the sort happens, when I am miles from help.
If a foreign body lodges beneath the lower eyelid, there is little or no pain; but if beneath the upper lid, or if embedded in the eyeball, a man is quite out of action until the thing is removed. If the offender cannot be seen, it is probably under the upper lid. When a man is alone, the best he can do in such a case is to pull the upper lid over the lower and hold it so until the tears have a chance to wash the irritating particle away. Close the nostril on the other side, and blow your nose hard. Do not rub the eye, for that might embed the thing.
In examining another person's eye, first have him look up while you press the lower lid down. If the particle is under the upper lid, have him sit down with head bent backward. Stand behind him, place a match across the upper lid half an inch from its edge, and turn the lid up and back over the match.
After a foreign substance has been removed, a few drops of olive oil or castor oil will soothe the eye. This is the best treatment, too, if there is a splinter that you are unable to remove by careful picking.
The best wash for inflamed eyes is boric acid in as little water as is required to dissolve it.