Eye pain, worsening redness, light sensitivity, discharge, a gritty feeling that will not go away, or a sudden change in vision should be checked. New flashes of light or a sudden shower of floaters also need prompt attention. If you wear contacts, remove them before calling.
Some injuries cannot wait for a clinic. For chemical splashes, penetrating injuries, severe trauma, or sudden vision loss with stroke-like symptoms such as weakness, facial drooping, or difficulty speaking, call 911 or go to the nearest hospital emergency department. Rinse a chemical splash with clean water while help is on the way.