Most chemicals just cause temporary stinging and irritation (for example, alcohol or hydrocarbons such as those in hairsprays are safe). However, acids and alkalis splashed into the eye can severely damage the cornea (clear part of the eye). All should be treated as emergencies until your healthcare provider or a Poison Control Center expert tells you otherwise.
Immediate and thorough flooding of the eye with tap water is needed to prevent damage to the cornea. Do this as quickly as possible. Either hold your child's face up under a gently running water tap or have your child lie down and continuously pour lukewarm water into the eye from a pitcher or glass. If there is no water handy, use milk. It is very important to hold the eyelids open during this process. For most chemicals, you should flush the eye for 15 to 30 minutes. Call your child's provider IMMEDIATELY after flushing the eye with water.