Causes

• Viral conjunctivitis (part of a cold) is the main cause. Almost always involves both eyes.
• Allergic conjunctivitis from pollens
• Mild chemical conjunctivitis from irritants (e.g., sunscreen, soap, chlorinated pool water, smoke, or smog)
• Irritants transferred by touching the eye may just involve one eye (e.g., food or plant resins on the fingers)