Getting unexpectedly splashed or sprayed in the eye by substances, other than clean, harmless water can be frightening and harmful. Some substances burn or sting but are fairly harmless in the long run, while others can cause serious injury. The basic makeup of the chemical involved makes all the difference, such as whether it is acidic or alkaline in composition.
As a general rule, acids can cause considerable redness and burning but can be washed out fairly easily.
Substances or chemicals that are basic (alkali) are much more serious but may not seem so because they do not cause as much immediate eye pain or redness as acids. Some examples of alkali substances are oven cleaners, toilet bowl cleaners, bleach, hair dye, mortar, paint, whitewash, and other household cleaners.