A subconjunctival hemorrhage (sub-kun-JUNK-tih-vul HEM-uh-ruj) occurs when a tiny blood vessel breaks just underneath the clear surface of your eye (conjunctiva). The conjunctiva can't absorb blood very quickly, so the blood gets trapped. You may not even realize you have a subconjunctival hemorrhage until you look in the mirror and notice the white part of your eye is bright red.

A subconjunctival hemorrhage often occurs without any obvious harm to your eye. Even a strong sneeze or cough can cause a blood vessel to break in the eye. You don't need to treat it. Your symptoms may worry you. But a subconjunctival hemorrhage is usually a harmless condition that disappears within two weeks or so.