The most common eye accident is a piece of dirt under the eye lid. If it does not come out with a few blinks it is wise not to blink any more but turn the eye lid and remove the dirt.
If no obvious piece of dirt is visible it is good to wipe the conjunctival surface with a wet cotton swab. The piece may be very small or translucent. If the sensation of foreign body in the eye does not disappear it is best to contact an eye doctor. Quite often the irritating piece is so small that it is found only with a microscope.
Sometimes a drop of a chemical happens to get into the eye. All chemicals should be rinsed away immediately. In places where chemicals are used people should always use goggles and have rinsing solution at hand. Artificial tear fluid is a convenient rinsing solution in the first aid kit for travelling. It is a perfect 'first aid' during long flight when the tear layer on the cornea becomes too thin and uneven.